Line 124: | Line 124: | ||
− | + | <h2><a name='header-n2' class='md-header-anchor '></a>Introduction</h2><p> In this model, we simplify the actual biology process into basic model that only remains input molecule, promotor, transcription gene, mRNA, goal protein and output molecule from both dynamic perspective and responding ability. In developed model, we consider different conditions including the population growth, diffusion of signal and decay of signal molecules in cells. which will have influence on our block. Finally, we completely construct the model of our block, which will instruct our experiment results and using of our system. Moreover, this model does some basic researches on population and new measurement methods. </p><h3><a name='header-n5' class='md-header-anchor '></a>Aim</h3><ol start='' ><li>Develop the dynamic model of genetic expression, which consider the influence of population of E.coli, diffusion of signal molecule and decay of signal molecules.</li><li>Solve the problem on parameter fitting in our experiments results.</li><li>Give a measurement method on determing the efficiency of signal converter.</li><li>Use both theoritical simulation and experiments results to indicate the main factor affecting the growth of E.coli.</li></ol><h3><a name='header-n19' class='md-header-anchor '></a>Symbol</h3><table><thead><tr><th>Symbol</th><th>Meaning</th></tr></thead><tbody><tr><td>$v_{generate}$</td><td>The generation efficency of mRNA</td></tr><tr><td>$[X]$</td><td>The concentration of substance $X$</td></tr><tr><td>$g_{X}$</td><td>The generation rate of substance $X$</td></tr><tr><td>$\phi_{X}$</td><td>The decay rate of substance $X$</td></tr><tr><td>$V_{\max}$</td><td>The maximum rate of generation</td></tr><tr><td>$C_{saturated}$</td><td>The saturated concentration</td></tr><tr><td>$N_{\max}$</td><td>The maximum population</td></tr><tr><td>$r$</td><td>Growth rate of E.coli</td></tr><tr><td>$[S]_t$</td><td>Function of signal molecule decay</td></tr><tr><td>$R(t)$</td><td>Function of mRNA generate</td></tr></tbody></table><h3><a name='header-n54' class='md-header-anchor '></a>Assumption</h3><ol start='' ><li>mRNA and proteins will decay following Poisson distribution (equivalent to birth-and-death process)</li><li>All combinations of two proteins are considered as quick reactions (Only control by thermodynamics)</li><li>The constitutive promoter has a constant rate to transcript proteins.</li><li>All raw materials inside cells can be considered as constants.</li></ol> | |
− | \frac{d([mRNA])}{dt}=v_{generate}-\phi_{mRNA}[mRNA]\\ | + | |
− | \frac{d([protein])}{dt}=g_{protein}[mRNA]-\phi_{protein}[protein] | + | <h3><a name='header-n68' class='md-header-anchor '></a>Basic Model</h3> |
− | + | $$ \begin{aligned} \frac{d([mRNA])}{dt}&=v_{generate}-\phi_{mRNA}[mRNA]\\ \frac{d([protein])}{dt}&=g_{protein}[mRNA]-\phi_{protein}[protein]\end{aligned} $$ | |
+ | |||
+ | <p> In these equations, $v_{generate}$ refers to the efficiency of mRNA transcription. $\phi$ refers to the degradation rate of mRNA and protein. </p><p> The property of $v<em>{generate}$ depends on the promoter and the concentration of inducer molecule. If the promoter is pcons, $v</em>{generate}$ is a constant. Otherwise, it will have a sensitive response to different concentration of inducer molecule. This reponse can be expressed as following form:</p><div contenteditable="false" class="mathjax-block md-end-block" id="mathjax-n73" cid="n73" mdtype="math_block"><span class="MathJax_Preview"></span><span class="MathJax_SVG_Display" style="text-align: center;"><span class="MathJax_SVG" id="MathJax-Element-2-Frame" tabindex="-1" style="font-size: 100%; display: inline-block;"><svg xmlns:xlink="http://www.w3.org/1999/xlink" width="39.102ex" height="5.612ex" viewBox="0 -1560 16835.6 2416.4" role="img" focusable="false" style="vertical-align: -1.989ex;"><defs><path stroke-width="1" id="E2-MJMATHI-76" d="M173 380Q173 405 154 405Q130 405 104 376T61 287Q60 286 59 284T58 281T56 279T53 278T49 278T41 278H27Q21 284 21 287Q21 294 29 316T53 368T97 419T160 441Q202 441 225 417T249 361Q249 344 246 335Q246 329 231 291T200 202T182 113Q182 86 187 69Q200 26 250 26Q287 26 319 60T369 139T398 222T409 277Q409 300 401 317T383 343T365 361T357 383Q357 405 376 424T417 443Q436 443 451 425T467 367Q467 340 455 284T418 159T347 40T241 -11Q177 -11 139 22Q102 54 102 117Q102 148 110 181T151 298Q173 362 173 380Z"></path><path stroke-width="1" id="E2-MJMATHI-67" d="M311 43Q296 30 267 15T206 0Q143 0 105 45T66 160Q66 265 143 353T314 442Q361 442 401 394L404 398Q406 401 409 404T418 412T431 419T447 422Q461 422 470 413T480 394Q480 379 423 152T363 -80Q345 -134 286 -169T151 -205Q10 -205 10 -137Q10 -111 28 -91T74 -71Q89 -71 102 -80T116 -111Q116 -121 114 -130T107 -144T99 -154T92 -162L90 -164H91Q101 -167 151 -167Q189 -167 211 -155Q234 -144 254 -122T282 -75Q288 -56 298 -13Q311 35 311 43ZM384 328L380 339Q377 350 375 354T369 368T359 382T346 393T328 402T306 405Q262 405 221 352Q191 313 171 233T151 117Q151 38 213 38Q269 38 323 108L331 118L384 328Z"></path><path stroke-width="1" id="E2-MJMATHI-65" d="M39 168Q39 225 58 272T107 350T174 402T244 433T307 442H310Q355 442 388 420T421 355Q421 265 310 237Q261 224 176 223Q139 223 138 221Q138 219 132 186T125 128Q125 81 146 54T209 26T302 45T394 111Q403 121 406 121Q410 121 419 112T429 98T420 82T390 55T344 24T281 -1T205 -11Q126 -11 83 42T39 168ZM373 353Q367 405 305 405Q272 405 244 391T199 357T170 316T154 280T149 261Q149 260 169 260Q282 260 327 284T373 353Z"></path><path stroke-width="1" id="E2-MJMATHI-6E" d="M21 287Q22 293 24 303T36 341T56 388T89 425T135 442Q171 442 195 424T225 390T231 369Q231 367 232 367L243 378Q304 442 382 442Q436 442 469 415T503 336T465 179T427 52Q427 26 444 26Q450 26 453 27Q482 32 505 65T540 145Q542 153 560 153Q580 153 580 145Q580 144 576 130Q568 101 554 73T508 17T439 -10Q392 -10 371 17T350 73Q350 92 386 193T423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 180T152 343Q153 348 153 366Q153 405 129 405Q91 405 66 305Q60 285 60 284Q58 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E2-MJMATHI-72" d="M21 287Q22 290 23 295T28 317T38 348T53 381T73 411T99 433T132 442Q161 442 183 430T214 408T225 388Q227 382 228 382T236 389Q284 441 347 441H350Q398 441 422 400Q430 381 430 363Q430 333 417 315T391 292T366 288Q346 288 334 299T322 328Q322 376 378 392Q356 405 342 405Q286 405 239 331Q229 315 224 298T190 165Q156 25 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 114 189T154 366Q154 405 128 405Q107 405 92 377T68 316T57 280Q55 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E2-MJMATHI-61" d="M33 157Q33 258 109 349T280 441Q331 441 370 392Q386 422 416 422Q429 422 439 414T449 394Q449 381 412 234T374 68Q374 43 381 35T402 26Q411 27 422 35Q443 55 463 131Q469 151 473 152Q475 153 483 153H487Q506 153 506 144Q506 138 501 117T481 63T449 13Q436 0 417 -8Q409 -10 393 -10Q359 -10 336 5T306 36L300 51Q299 52 296 50Q294 48 292 46Q233 -10 172 -10Q117 -10 75 30T33 157ZM351 328Q351 334 346 350T323 385T277 405Q242 405 210 374T160 293Q131 214 119 129Q119 126 119 118T118 106Q118 61 136 44T179 26Q217 26 254 59T298 110Q300 114 325 217T351 328Z"></path><path stroke-width="1" id="E2-MJMATHI-74" d="M26 385Q19 392 19 395Q19 399 22 411T27 425Q29 430 36 430T87 431H140L159 511Q162 522 166 540T173 566T179 586T187 603T197 615T211 624T229 626Q247 625 254 615T261 596Q261 589 252 549T232 470L222 433Q222 431 272 431H323Q330 424 330 420Q330 398 317 385H210L174 240Q135 80 135 68Q135 26 162 26Q197 26 230 60T283 144Q285 150 288 151T303 153H307Q322 153 322 145Q322 142 319 133Q314 117 301 95T267 48T216 6T155 -11Q125 -11 98 4T59 56Q57 64 57 83V101L92 241Q127 382 128 383Q128 385 77 385H26Z"></path><path stroke-width="1" id="E2-MJMAIN-28" d="M94 250Q94 319 104 381T127 488T164 576T202 643T244 695T277 729T302 750H315H319Q333 750 333 741Q333 738 316 720T275 667T226 581T184 443T167 250T184 58T225 -81T274 -167T316 -220T333 -241Q333 -250 318 -250H315H302L274 -226Q180 -141 137 -14T94 250Z"></path><path stroke-width="1" id="E2-MJMAIN-5B" d="M118 -250V750H255V710H158V-210H255V-250H118Z"></path><path stroke-width="1" id="E2-MJMATHI-78" d="M52 289Q59 331 106 386T222 442Q257 442 286 424T329 379Q371 442 430 442Q467 442 494 420T522 361Q522 332 508 314T481 292T458 288Q439 288 427 299T415 328Q415 374 465 391Q454 404 425 404Q412 404 406 402Q368 386 350 336Q290 115 290 78Q290 50 306 38T341 26Q378 26 414 59T463 140Q466 150 469 151T485 153H489Q504 153 504 145Q504 144 502 134Q486 77 440 33T333 -11Q263 -11 227 52Q186 -10 133 -10H127Q78 -10 57 16T35 71Q35 103 54 123T99 143Q142 143 142 101Q142 81 130 66T107 46T94 41L91 40Q91 39 97 36T113 29T132 26Q168 26 194 71Q203 87 217 139T245 247T261 313Q266 340 266 352Q266 380 251 392T217 404Q177 404 142 372T93 290Q91 281 88 280T72 278H58Q52 284 52 289Z"></path><path stroke-width="1" id="E2-MJMAIN-5D" d="M22 710V750H159V-250H22V-210H119V710H22Z"></path><path stroke-width="1" id="E2-MJMAIN-29" d="M60 749L64 750Q69 750 74 750H86L114 726Q208 641 251 514T294 250Q294 182 284 119T261 12T224 -76T186 -143T145 -194T113 -227T90 -246Q87 -249 86 -250H74Q66 -250 63 -250T58 -247T55 -238Q56 -237 66 -225Q221 -64 221 250T66 725Q56 737 55 738Q55 746 60 749Z"></path><path stroke-width="1" id="E2-MJMAIN-3D" d="M56 347Q56 360 70 367H707Q722 359 722 347Q722 336 708 328L390 327H72Q56 332 56 347ZM56 153Q56 168 72 173H708Q722 163 722 153Q722 140 707 133H70Q56 140 56 153Z"></path><path stroke-width="1" id="E2-MJMATHI-56" d="M52 648Q52 670 65 683H76Q118 680 181 680Q299 680 320 683H330Q336 677 336 674T334 656Q329 641 325 637H304Q282 635 274 635Q245 630 242 620Q242 618 271 369T301 118L374 235Q447 352 520 471T595 594Q599 601 599 609Q599 633 555 637Q537 637 537 648Q537 649 539 661Q542 675 545 679T558 683Q560 683 570 683T604 682T668 681Q737 681 755 683H762Q769 676 769 672Q769 655 760 640Q757 637 743 637Q730 636 719 635T698 630T682 623T670 615T660 608T652 599T645 592L452 282Q272 -9 266 -16Q263 -18 259 -21L241 -22H234Q216 -22 216 -15Q213 -9 177 305Q139 623 138 626Q133 637 76 637H59Q52 642 52 648Z"></path><path stroke-width="1" id="E2-MJMATHI-6D" d="M21 287Q22 293 24 303T36 341T56 388T88 425T132 442T175 435T205 417T221 395T229 376L231 369Q231 367 232 367L243 378Q303 442 384 442Q401 442 415 440T441 433T460 423T475 411T485 398T493 385T497 373T500 364T502 357L510 367Q573 442 659 442Q713 442 746 415T780 336Q780 285 742 178T704 50Q705 36 709 31T724 26Q752 26 776 56T815 138Q818 149 821 151T837 153Q857 153 857 145Q857 144 853 130Q845 101 831 73T785 17T716 -10Q669 -10 648 17T627 73Q627 92 663 193T700 345Q700 404 656 404H651Q565 404 506 303L499 291L466 157Q433 26 428 16Q415 -11 385 -11Q372 -11 364 -4T353 8T350 18Q350 29 384 161L420 307Q423 322 423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 181Q151 335 151 342Q154 357 154 369Q154 405 129 405Q107 405 92 377T69 316T57 280Q55 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E2-MJMAIN-22C5" d="M78 250Q78 274 95 292T138 310Q162 310 180 294T199 251Q199 226 182 208T139 190T96 207T78 250Z"></path><path stroke-width="1" id="E2-MJMAIN-31" d="M213 578L200 573Q186 568 160 563T102 556H83V602H102Q149 604 189 617T245 641T273 663Q275 666 285 666Q294 666 302 660V361L303 61Q310 54 315 52T339 48T401 46H427V0H416Q395 3 257 3Q121 3 100 0H88V46H114Q136 46 152 46T177 47T193 50T201 52T207 57T213 61V578Z"></path><path stroke-width="1" id="E2-MJMAIN-2212" d="M84 237T84 250T98 270H679Q694 262 694 250T679 230H98Q84 237 84 250Z"></path><path stroke-width="1" id="E2-MJMATHI-3F5" d="M227 -11Q149 -11 95 41T40 174Q40 262 87 322Q121 367 173 396T287 430Q289 431 329 431H367Q382 426 382 411Q382 385 341 385H325H312Q191 385 154 277L150 265H327Q340 256 340 246Q340 228 320 219H138V217Q128 187 128 143Q128 77 160 52T231 26Q258 26 284 36T326 57T343 68Q350 68 354 58T358 39Q358 36 357 35Q354 31 337 21T289 0T227 -11Z"></path><path stroke-width="1" id="E2-MJMATHI-6B" d="M121 647Q121 657 125 670T137 683Q138 683 209 688T282 694Q294 694 294 686Q294 679 244 477Q194 279 194 272Q213 282 223 291Q247 309 292 354T362 415Q402 442 438 442Q468 442 485 423T503 369Q503 344 496 327T477 302T456 291T438 288Q418 288 406 299T394 328Q394 353 410 369T442 390L458 393Q446 405 434 405H430Q398 402 367 380T294 316T228 255Q230 254 243 252T267 246T293 238T320 224T342 206T359 180T365 147Q365 130 360 106T354 66Q354 26 381 26Q429 26 459 145Q461 153 479 153H483Q499 153 499 144Q499 139 496 130Q455 -11 378 -11Q333 -11 305 15T277 90Q277 108 280 121T283 145Q283 167 269 183T234 206T200 217T182 220H180Q168 178 159 139T145 81T136 44T129 20T122 7T111 -2Q98 -11 83 -11Q66 -11 57 -1T48 16Q48 26 85 176T158 471L195 616Q196 629 188 632T149 637H144Q134 637 131 637T124 640T121 647Z"></path><path stroke-width="1" id="E2-MJMAIN-2B" d="M56 237T56 250T70 270H369V420L370 570Q380 583 389 583Q402 583 409 568V270H707Q722 262 722 250T707 230H409V-68Q401 -82 391 -82H389H387Q375 -82 369 -68V230H70Q56 237 56 250Z"></path></defs><g stroke="currentColor" fill="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><use xlink:href="#E2-MJMATHI-76" x="0" y="0"></use><g transform="translate(485,-150)"><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-67" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-65" x="480" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-6E" x="947" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-65" x="1547" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-72" x="2014" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-61" x="2465" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-74" x="2995" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-65" x="3356" y="0"></use></g><use xlink:href="#E2-MJMAIN-28" x="3288" y="0"></use><use xlink:href="#E2-MJMAIN-5B" x="3678" y="0"></use><use xlink:href="#E2-MJMATHI-78" x="3956" y="0"></use><use xlink:href="#E2-MJMAIN-5D" x="4529" y="0"></use><use xlink:href="#E2-MJMAIN-29" x="4807" y="0"></use><use xlink:href="#E2-MJMAIN-3D" x="5475" y="0"></use><g transform="translate(6531,0)"><use xlink:href="#E2-MJMATHI-56" x="0" y="0"></use><g transform="translate(583,-150)"><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-6D" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-61" x="878" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-78" x="1408" y="0"></use></g></g><use xlink:href="#E2-MJMAIN-22C5" x="8837" y="0"></use><use xlink:href="#E2-MJMAIN-28" x="9338" y="0"></use><g transform="translate(9727,0)"><g transform="translate(120,0)"><rect stroke="none" width="4849" height="60" x="0" y="220"></rect><g transform="translate(60,716)"><use xlink:href="#E2-MJMAIN-28" x="0" y="0"></use><use xlink:href="#E2-MJMAIN-31" x="389" y="0"></use><use xlink:href="#E2-MJMAIN-2212" x="1112" y="0"></use><use xlink:href="#E2-MJMATHI-3F5" x="2112" y="0"></use><use xlink:href="#E2-MJMAIN-29" x="2519" y="0"></use><use xlink:href="#E2-MJMAIN-22C5" x="3131" y="0"></use><g transform="translate(3631,0)"><use xlink:href="#E2-MJMATHI-78" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-6E" x="809" y="513"></use></g></g><g transform="translate(741,-686)"><use xlink:href="#E2-MJMATHI-6B" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-6E" x="737" y="408"></use><use xlink:href="#E2-MJMAIN-2B" x="1268" y="0"></use><g transform="translate(2269,0)"><use xlink:href="#E2-MJMATHI-78" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E2-MJMATHI-6E" x="809" y="408"></use></g></g></g></g><use xlink:href="#E2-MJMAIN-2B" x="15038" y="0"></use><use xlink:href="#E2-MJMATHI-3F5" x="16039" y="0"></use><use xlink:href="#E2-MJMAIN-29" x="16446" y="0"></use></g></svg></span></span><script type="math/tex; mode=display" id="MathJax-Element-2"> | ||
v_{generate}([x])=V_{max}·(\frac{(1-\epsilon)·x^n}{k^n+x^n}+\epsilon) | v_{generate}([x])=V_{max}·(\frac{(1-\epsilon)·x^n}{k^n+x^n}+\epsilon) | ||
</script></div><p> $k$ refers to the dissociation constant and $x$ refers to the concentration of inducer concentration. $\epsilon$ refers to the leakage of genetic expression.</p><p> In comparision, for NOR GATE, the repression of inducer molecule can be expressed as similar form:</p><div contenteditable="false" class="mathjax-block md-end-block" id="mathjax-n78" cid="n78" mdtype="math_block"><span class="MathJax_Preview"></span><span class="MathJax_SVG_Display" style="text-align: center;"><span class="MathJax_SVG" id="MathJax-Element-3-Frame" tabindex="-1" style="font-size: 100%; display: inline-block;"><svg xmlns:xlink="http://www.w3.org/1999/xlink" width="38.144ex" height="6.079ex" viewBox="0 -1409.3 16423.1 2617.5" role="img" focusable="false" style="vertical-align: -2.806ex;"><defs><path stroke-width="1" id="E3-MJMATHI-76" d="M173 380Q173 405 154 405Q130 405 104 376T61 287Q60 286 59 284T58 281T56 279T53 278T49 278T41 278H27Q21 284 21 287Q21 294 29 316T53 368T97 419T160 441Q202 441 225 417T249 361Q249 344 246 335Q246 329 231 291T200 202T182 113Q182 86 187 69Q200 26 250 26Q287 26 319 60T369 139T398 222T409 277Q409 300 401 317T383 343T365 361T357 383Q357 405 376 424T417 443Q436 443 451 425T467 367Q467 340 455 284T418 159T347 40T241 -11Q177 -11 139 22Q102 54 102 117Q102 148 110 181T151 298Q173 362 173 380Z"></path><path stroke-width="1" id="E3-MJMATHI-67" d="M311 43Q296 30 267 15T206 0Q143 0 105 45T66 160Q66 265 143 353T314 442Q361 442 401 394L404 398Q406 401 409 404T418 412T431 419T447 422Q461 422 470 413T480 394Q480 379 423 152T363 -80Q345 -134 286 -169T151 -205Q10 -205 10 -137Q10 -111 28 -91T74 -71Q89 -71 102 -80T116 -111Q116 -121 114 -130T107 -144T99 -154T92 -162L90 -164H91Q101 -167 151 -167Q189 -167 211 -155Q234 -144 254 -122T282 -75Q288 -56 298 -13Q311 35 311 43ZM384 328L380 339Q377 350 375 354T369 368T359 382T346 393T328 402T306 405Q262 405 221 352Q191 313 171 233T151 117Q151 38 213 38Q269 38 323 108L331 118L384 328Z"></path><path stroke-width="1" id="E3-MJMATHI-65" d="M39 168Q39 225 58 272T107 350T174 402T244 433T307 442H310Q355 442 388 420T421 355Q421 265 310 237Q261 224 176 223Q139 223 138 221Q138 219 132 186T125 128Q125 81 146 54T209 26T302 45T394 111Q403 121 406 121Q410 121 419 112T429 98T420 82T390 55T344 24T281 -1T205 -11Q126 -11 83 42T39 168ZM373 353Q367 405 305 405Q272 405 244 391T199 357T170 316T154 280T149 261Q149 260 169 260Q282 260 327 284T373 353Z"></path><path stroke-width="1" id="E3-MJMATHI-6E" d="M21 287Q22 293 24 303T36 341T56 388T89 425T135 442Q171 442 195 424T225 390T231 369Q231 367 232 367L243 378Q304 442 382 442Q436 442 469 415T503 336T465 179T427 52Q427 26 444 26Q450 26 453 27Q482 32 505 65T540 145Q542 153 560 153Q580 153 580 145Q580 144 576 130Q568 101 554 73T508 17T439 -10Q392 -10 371 17T350 73Q350 92 386 193T423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 180T152 343Q153 348 153 366Q153 405 129 405Q91 405 66 305Q60 285 60 284Q58 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E3-MJMATHI-72" d="M21 287Q22 290 23 295T28 317T38 348T53 381T73 411T99 433T132 442Q161 442 183 430T214 408T225 388Q227 382 228 382T236 389Q284 441 347 441H350Q398 441 422 400Q430 381 430 363Q430 333 417 315T391 292T366 288Q346 288 334 299T322 328Q322 376 378 392Q356 405 342 405Q286 405 239 331Q229 315 224 298T190 165Q156 25 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 114 189T154 366Q154 405 128 405Q107 405 92 377T68 316T57 280Q55 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E3-MJMATHI-61" d="M33 157Q33 258 109 349T280 441Q331 441 370 392Q386 422 416 422Q429 422 439 414T449 394Q449 381 412 234T374 68Q374 43 381 35T402 26Q411 27 422 35Q443 55 463 131Q469 151 473 152Q475 153 483 153H487Q506 153 506 144Q506 138 501 117T481 63T449 13Q436 0 417 -8Q409 -10 393 -10Q359 -10 336 5T306 36L300 51Q299 52 296 50Q294 48 292 46Q233 -10 172 -10Q117 -10 75 30T33 157ZM351 328Q351 334 346 350T323 385T277 405Q242 405 210 374T160 293Q131 214 119 129Q119 126 119 118T118 106Q118 61 136 44T179 26Q217 26 254 59T298 110Q300 114 325 217T351 328Z"></path><path stroke-width="1" id="E3-MJMATHI-74" d="M26 385Q19 392 19 395Q19 399 22 411T27 425Q29 430 36 430T87 431H140L159 511Q162 522 166 540T173 566T179 586T187 603T197 615T211 624T229 626Q247 625 254 615T261 596Q261 589 252 549T232 470L222 433Q222 431 272 431H323Q330 424 330 420Q330 398 317 385H210L174 240Q135 80 135 68Q135 26 162 26Q197 26 230 60T283 144Q285 150 288 151T303 153H307Q322 153 322 145Q322 142 319 133Q314 117 301 95T267 48T216 6T155 -11Q125 -11 98 4T59 56Q57 64 57 83V101L92 241Q127 382 128 383Q128 385 77 385H26Z"></path><path stroke-width="1" id="E3-MJMAIN-28" d="M94 250Q94 319 104 381T127 488T164 576T202 643T244 695T277 729T302 750H315H319Q333 750 333 741Q333 738 316 720T275 667T226 581T184 443T167 250T184 58T225 -81T274 -167T316 -220T333 -241Q333 -250 318 -250H315H302L274 -226Q180 -141 137 -14T94 250Z"></path><path stroke-width="1" id="E3-MJMAIN-5B" d="M118 -250V750H255V710H158V-210H255V-250H118Z"></path><path stroke-width="1" id="E3-MJMATHI-78" d="M52 289Q59 331 106 386T222 442Q257 442 286 424T329 379Q371 442 430 442Q467 442 494 420T522 361Q522 332 508 314T481 292T458 288Q439 288 427 299T415 328Q415 374 465 391Q454 404 425 404Q412 404 406 402Q368 386 350 336Q290 115 290 78Q290 50 306 38T341 26Q378 26 414 59T463 140Q466 150 469 151T485 153H489Q504 153 504 145Q504 144 502 134Q486 77 440 33T333 -11Q263 -11 227 52Q186 -10 133 -10H127Q78 -10 57 16T35 71Q35 103 54 123T99 143Q142 143 142 101Q142 81 130 66T107 46T94 41L91 40Q91 39 97 36T113 29T132 26Q168 26 194 71Q203 87 217 139T245 247T261 313Q266 340 266 352Q266 380 251 392T217 404Q177 404 142 372T93 290Q91 281 88 280T72 278H58Q52 284 52 289Z"></path><path stroke-width="1" id="E3-MJMAIN-5D" d="M22 710V750H159V-250H22V-210H119V710H22Z"></path><path stroke-width="1" id="E3-MJMAIN-29" d="M60 749L64 750Q69 750 74 750H86L114 726Q208 641 251 514T294 250Q294 182 284 119T261 12T224 -76T186 -143T145 -194T113 -227T90 -246Q87 -249 86 -250H74Q66 -250 63 -250T58 -247T55 -238Q56 -237 66 -225Q221 -64 221 250T66 725Q56 737 55 738Q55 746 60 749Z"></path><path stroke-width="1" id="E3-MJMAIN-3D" d="M56 347Q56 360 70 367H707Q722 359 722 347Q722 336 708 328L390 327H72Q56 332 56 347ZM56 153Q56 168 72 173H708Q722 163 722 153Q722 140 707 133H70Q56 140 56 153Z"></path><path stroke-width="1" id="E3-MJMATHI-56" d="M52 648Q52 670 65 683H76Q118 680 181 680Q299 680 320 683H330Q336 677 336 674T334 656Q329 641 325 637H304Q282 635 274 635Q245 630 242 620Q242 618 271 369T301 118L374 235Q447 352 520 471T595 594Q599 601 599 609Q599 633 555 637Q537 637 537 648Q537 649 539 661Q542 675 545 679T558 683Q560 683 570 683T604 682T668 681Q737 681 755 683H762Q769 676 769 672Q769 655 760 640Q757 637 743 637Q730 636 719 635T698 630T682 623T670 615T660 608T652 599T645 592L452 282Q272 -9 266 -16Q263 -18 259 -21L241 -22H234Q216 -22 216 -15Q213 -9 177 305Q139 623 138 626Q133 637 76 637H59Q52 642 52 648Z"></path><path stroke-width="1" id="E3-MJMATHI-6D" d="M21 287Q22 293 24 303T36 341T56 388T88 425T132 442T175 435T205 417T221 395T229 376L231 369Q231 367 232 367L243 378Q303 442 384 442Q401 442 415 440T441 433T460 423T475 411T485 398T493 385T497 373T500 364T502 357L510 367Q573 442 659 442Q713 442 746 415T780 336Q780 285 742 178T704 50Q705 36 709 31T724 26Q752 26 776 56T815 138Q818 149 821 151T837 153Q857 153 857 145Q857 144 853 130Q845 101 831 73T785 17T716 -10Q669 -10 648 17T627 73Q627 92 663 193T700 345Q700 404 656 404H651Q565 404 506 303L499 291L466 157Q433 26 428 16Q415 -11 385 -11Q372 -11 364 -4T353 8T350 18Q350 29 384 161L420 307Q423 322 423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 181Q151 335 151 342Q154 357 154 369Q154 405 129 405Q107 405 92 377T69 316T57 280Q55 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E3-MJMAIN-22C5" d="M78 250Q78 274 95 292T138 310Q162 310 180 294T199 251Q199 226 182 208T139 190T96 207T78 250Z"></path><path stroke-width="1" id="E3-MJMAIN-31" d="M213 578L200 573Q186 568 160 563T102 556H83V602H102Q149 604 189 617T245 641T273 663Q275 666 285 666Q294 666 302 660V361L303 61Q310 54 315 52T339 48T401 46H427V0H416Q395 3 257 3Q121 3 100 0H88V46H114Q136 46 152 46T177 47T193 50T201 52T207 57T213 61V578Z"></path><path stroke-width="1" id="E3-MJMAIN-2212" d="M84 237T84 250T98 270H679Q694 262 694 250T679 230H98Q84 237 84 250Z"></path><path stroke-width="1" id="E3-MJMATHI-3F5" d="M227 -11Q149 -11 95 41T40 174Q40 262 87 322Q121 367 173 396T287 430Q289 431 329 431H367Q382 426 382 411Q382 385 341 385H325H312Q191 385 154 277L150 265H327Q340 256 340 246Q340 228 320 219H138V217Q128 187 128 143Q128 77 160 52T231 26Q258 26 284 36T326 57T343 68Q350 68 354 58T358 39Q358 36 357 35Q354 31 337 21T289 0T227 -11Z"></path><path stroke-width="1" id="E3-MJMAIN-2B" d="M56 237T56 250T70 270H369V420L370 570Q380 583 389 583Q402 583 409 568V270H707Q722 262 722 250T707 230H409V-68Q401 -82 391 -82H389H387Q375 -82 369 -68V230H70Q56 237 56 250Z"></path><path stroke-width="1" id="E3-MJMATHI-6B" d="M121 647Q121 657 125 670T137 683Q138 683 209 688T282 694Q294 694 294 686Q294 679 244 477Q194 279 194 272Q213 282 223 291Q247 309 292 354T362 415Q402 442 438 442Q468 442 485 423T503 369Q503 344 496 327T477 302T456 291T438 288Q418 288 406 299T394 328Q394 353 410 369T442 390L458 393Q446 405 434 405H430Q398 402 367 380T294 316T228 255Q230 254 243 252T267 246T293 238T320 224T342 206T359 180T365 147Q365 130 360 106T354 66Q354 26 381 26Q429 26 459 145Q461 153 479 153H483Q499 153 499 144Q499 139 496 130Q455 -11 378 -11Q333 -11 305 15T277 90Q277 108 280 121T283 145Q283 167 269 183T234 206T200 217T182 220H180Q168 178 159 139T145 81T136 44T129 20T122 7T111 -2Q98 -11 83 -11Q66 -11 57 -1T48 16Q48 26 85 176T158 471L195 616Q196 629 188 632T149 637H144Q134 637 131 637T124 640T121 647Z"></path></defs><g stroke="currentColor" fill="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><use xlink:href="#E3-MJMATHI-76" x="0" y="0"></use><g transform="translate(485,-150)"><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-67" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-65" x="480" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6E" x="947" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-65" x="1547" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-72" x="2014" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-61" x="2465" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-74" x="2995" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-65" x="3356" y="0"></use></g><use xlink:href="#E3-MJMAIN-28" x="3288" y="0"></use><use xlink:href="#E3-MJMAIN-5B" x="3678" y="0"></use><use xlink:href="#E3-MJMATHI-78" x="3956" y="0"></use><use xlink:href="#E3-MJMAIN-5D" x="4529" y="0"></use><use xlink:href="#E3-MJMAIN-29" x="4807" y="0"></use><use xlink:href="#E3-MJMAIN-3D" x="5475" y="0"></use><g transform="translate(6531,0)"><use xlink:href="#E3-MJMATHI-56" x="0" y="0"></use><g transform="translate(583,-150)"><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6D" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-61" x="878" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-78" x="1408" y="0"></use></g></g><use xlink:href="#E3-MJMAIN-22C5" x="8837" y="0"></use><use xlink:href="#E3-MJMAIN-28" x="9338" y="0"></use><g transform="translate(9727,0)"><g transform="translate(120,0)"><rect stroke="none" width="4436" height="60" x="0" y="220"></rect><g transform="translate(1153,676)"><use xlink:href="#E3-MJMAIN-31" x="0" y="0"></use><use xlink:href="#E3-MJMAIN-2212" x="722" y="0"></use><use xlink:href="#E3-MJMATHI-3F5" x="1723" y="0"></use></g><g transform="translate(60,-717)"><use xlink:href="#E3-MJMAIN-31" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6E" x="707" y="557"></use><use xlink:href="#E3-MJMAIN-2B" x="1247" y="0"></use><use xlink:href="#E3-MJMAIN-28" x="2248" y="0"></use><g transform="translate(2637,0)"><g transform="translate(120,0)"><rect stroke="none" width="524" height="60" x="0" y="220"></rect><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-78" x="84" y="583"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6B" x="110" y="-560"></use></g></g><g transform="translate(3402,0)"><use xlink:href="#E3-MJMAIN-29" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6E" x="550" y="408"></use></g></g></g></g><use xlink:href="#E3-MJMAIN-2B" x="14626" y="0"></use><use xlink:href="#E3-MJMATHI-3F5" x="15627" y="0"></use><use xlink:href="#E3-MJMAIN-29" x="16033" y="0"></use></g></svg></span></span><script type="math/tex; mode=display" id="MathJax-Element-3"> | </script></div><p> $k$ refers to the dissociation constant and $x$ refers to the concentration of inducer concentration. $\epsilon$ refers to the leakage of genetic expression.</p><p> In comparision, for NOR GATE, the repression of inducer molecule can be expressed as similar form:</p><div contenteditable="false" class="mathjax-block md-end-block" id="mathjax-n78" cid="n78" mdtype="math_block"><span class="MathJax_Preview"></span><span class="MathJax_SVG_Display" style="text-align: center;"><span class="MathJax_SVG" id="MathJax-Element-3-Frame" tabindex="-1" style="font-size: 100%; display: inline-block;"><svg xmlns:xlink="http://www.w3.org/1999/xlink" width="38.144ex" height="6.079ex" viewBox="0 -1409.3 16423.1 2617.5" role="img" focusable="false" style="vertical-align: -2.806ex;"><defs><path stroke-width="1" id="E3-MJMATHI-76" d="M173 380Q173 405 154 405Q130 405 104 376T61 287Q60 286 59 284T58 281T56 279T53 278T49 278T41 278H27Q21 284 21 287Q21 294 29 316T53 368T97 419T160 441Q202 441 225 417T249 361Q249 344 246 335Q246 329 231 291T200 202T182 113Q182 86 187 69Q200 26 250 26Q287 26 319 60T369 139T398 222T409 277Q409 300 401 317T383 343T365 361T357 383Q357 405 376 424T417 443Q436 443 451 425T467 367Q467 340 455 284T418 159T347 40T241 -11Q177 -11 139 22Q102 54 102 117Q102 148 110 181T151 298Q173 362 173 380Z"></path><path stroke-width="1" id="E3-MJMATHI-67" d="M311 43Q296 30 267 15T206 0Q143 0 105 45T66 160Q66 265 143 353T314 442Q361 442 401 394L404 398Q406 401 409 404T418 412T431 419T447 422Q461 422 470 413T480 394Q480 379 423 152T363 -80Q345 -134 286 -169T151 -205Q10 -205 10 -137Q10 -111 28 -91T74 -71Q89 -71 102 -80T116 -111Q116 -121 114 -130T107 -144T99 -154T92 -162L90 -164H91Q101 -167 151 -167Q189 -167 211 -155Q234 -144 254 -122T282 -75Q288 -56 298 -13Q311 35 311 43ZM384 328L380 339Q377 350 375 354T369 368T359 382T346 393T328 402T306 405Q262 405 221 352Q191 313 171 233T151 117Q151 38 213 38Q269 38 323 108L331 118L384 328Z"></path><path stroke-width="1" id="E3-MJMATHI-65" d="M39 168Q39 225 58 272T107 350T174 402T244 433T307 442H310Q355 442 388 420T421 355Q421 265 310 237Q261 224 176 223Q139 223 138 221Q138 219 132 186T125 128Q125 81 146 54T209 26T302 45T394 111Q403 121 406 121Q410 121 419 112T429 98T420 82T390 55T344 24T281 -1T205 -11Q126 -11 83 42T39 168ZM373 353Q367 405 305 405Q272 405 244 391T199 357T170 316T154 280T149 261Q149 260 169 260Q282 260 327 284T373 353Z"></path><path stroke-width="1" id="E3-MJMATHI-6E" d="M21 287Q22 293 24 303T36 341T56 388T89 425T135 442Q171 442 195 424T225 390T231 369Q231 367 232 367L243 378Q304 442 382 442Q436 442 469 415T503 336T465 179T427 52Q427 26 444 26Q450 26 453 27Q482 32 505 65T540 145Q542 153 560 153Q580 153 580 145Q580 144 576 130Q568 101 554 73T508 17T439 -10Q392 -10 371 17T350 73Q350 92 386 193T423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 180T152 343Q153 348 153 366Q153 405 129 405Q91 405 66 305Q60 285 60 284Q58 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E3-MJMATHI-72" d="M21 287Q22 290 23 295T28 317T38 348T53 381T73 411T99 433T132 442Q161 442 183 430T214 408T225 388Q227 382 228 382T236 389Q284 441 347 441H350Q398 441 422 400Q430 381 430 363Q430 333 417 315T391 292T366 288Q346 288 334 299T322 328Q322 376 378 392Q356 405 342 405Q286 405 239 331Q229 315 224 298T190 165Q156 25 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 114 189T154 366Q154 405 128 405Q107 405 92 377T68 316T57 280Q55 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E3-MJMATHI-61" d="M33 157Q33 258 109 349T280 441Q331 441 370 392Q386 422 416 422Q429 422 439 414T449 394Q449 381 412 234T374 68Q374 43 381 35T402 26Q411 27 422 35Q443 55 463 131Q469 151 473 152Q475 153 483 153H487Q506 153 506 144Q506 138 501 117T481 63T449 13Q436 0 417 -8Q409 -10 393 -10Q359 -10 336 5T306 36L300 51Q299 52 296 50Q294 48 292 46Q233 -10 172 -10Q117 -10 75 30T33 157ZM351 328Q351 334 346 350T323 385T277 405Q242 405 210 374T160 293Q131 214 119 129Q119 126 119 118T118 106Q118 61 136 44T179 26Q217 26 254 59T298 110Q300 114 325 217T351 328Z"></path><path stroke-width="1" id="E3-MJMATHI-74" d="M26 385Q19 392 19 395Q19 399 22 411T27 425Q29 430 36 430T87 431H140L159 511Q162 522 166 540T173 566T179 586T187 603T197 615T211 624T229 626Q247 625 254 615T261 596Q261 589 252 549T232 470L222 433Q222 431 272 431H323Q330 424 330 420Q330 398 317 385H210L174 240Q135 80 135 68Q135 26 162 26Q197 26 230 60T283 144Q285 150 288 151T303 153H307Q322 153 322 145Q322 142 319 133Q314 117 301 95T267 48T216 6T155 -11Q125 -11 98 4T59 56Q57 64 57 83V101L92 241Q127 382 128 383Q128 385 77 385H26Z"></path><path stroke-width="1" id="E3-MJMAIN-28" d="M94 250Q94 319 104 381T127 488T164 576T202 643T244 695T277 729T302 750H315H319Q333 750 333 741Q333 738 316 720T275 667T226 581T184 443T167 250T184 58T225 -81T274 -167T316 -220T333 -241Q333 -250 318 -250H315H302L274 -226Q180 -141 137 -14T94 250Z"></path><path stroke-width="1" id="E3-MJMAIN-5B" d="M118 -250V750H255V710H158V-210H255V-250H118Z"></path><path stroke-width="1" id="E3-MJMATHI-78" d="M52 289Q59 331 106 386T222 442Q257 442 286 424T329 379Q371 442 430 442Q467 442 494 420T522 361Q522 332 508 314T481 292T458 288Q439 288 427 299T415 328Q415 374 465 391Q454 404 425 404Q412 404 406 402Q368 386 350 336Q290 115 290 78Q290 50 306 38T341 26Q378 26 414 59T463 140Q466 150 469 151T485 153H489Q504 153 504 145Q504 144 502 134Q486 77 440 33T333 -11Q263 -11 227 52Q186 -10 133 -10H127Q78 -10 57 16T35 71Q35 103 54 123T99 143Q142 143 142 101Q142 81 130 66T107 46T94 41L91 40Q91 39 97 36T113 29T132 26Q168 26 194 71Q203 87 217 139T245 247T261 313Q266 340 266 352Q266 380 251 392T217 404Q177 404 142 372T93 290Q91 281 88 280T72 278H58Q52 284 52 289Z"></path><path stroke-width="1" id="E3-MJMAIN-5D" d="M22 710V750H159V-250H22V-210H119V710H22Z"></path><path stroke-width="1" id="E3-MJMAIN-29" d="M60 749L64 750Q69 750 74 750H86L114 726Q208 641 251 514T294 250Q294 182 284 119T261 12T224 -76T186 -143T145 -194T113 -227T90 -246Q87 -249 86 -250H74Q66 -250 63 -250T58 -247T55 -238Q56 -237 66 -225Q221 -64 221 250T66 725Q56 737 55 738Q55 746 60 749Z"></path><path stroke-width="1" id="E3-MJMAIN-3D" d="M56 347Q56 360 70 367H707Q722 359 722 347Q722 336 708 328L390 327H72Q56 332 56 347ZM56 153Q56 168 72 173H708Q722 163 722 153Q722 140 707 133H70Q56 140 56 153Z"></path><path stroke-width="1" id="E3-MJMATHI-56" d="M52 648Q52 670 65 683H76Q118 680 181 680Q299 680 320 683H330Q336 677 336 674T334 656Q329 641 325 637H304Q282 635 274 635Q245 630 242 620Q242 618 271 369T301 118L374 235Q447 352 520 471T595 594Q599 601 599 609Q599 633 555 637Q537 637 537 648Q537 649 539 661Q542 675 545 679T558 683Q560 683 570 683T604 682T668 681Q737 681 755 683H762Q769 676 769 672Q769 655 760 640Q757 637 743 637Q730 636 719 635T698 630T682 623T670 615T660 608T652 599T645 592L452 282Q272 -9 266 -16Q263 -18 259 -21L241 -22H234Q216 -22 216 -15Q213 -9 177 305Q139 623 138 626Q133 637 76 637H59Q52 642 52 648Z"></path><path stroke-width="1" id="E3-MJMATHI-6D" d="M21 287Q22 293 24 303T36 341T56 388T88 425T132 442T175 435T205 417T221 395T229 376L231 369Q231 367 232 367L243 378Q303 442 384 442Q401 442 415 440T441 433T460 423T475 411T485 398T493 385T497 373T500 364T502 357L510 367Q573 442 659 442Q713 442 746 415T780 336Q780 285 742 178T704 50Q705 36 709 31T724 26Q752 26 776 56T815 138Q818 149 821 151T837 153Q857 153 857 145Q857 144 853 130Q845 101 831 73T785 17T716 -10Q669 -10 648 17T627 73Q627 92 663 193T700 345Q700 404 656 404H651Q565 404 506 303L499 291L466 157Q433 26 428 16Q415 -11 385 -11Q372 -11 364 -4T353 8T350 18Q350 29 384 161L420 307Q423 322 423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 181Q151 335 151 342Q154 357 154 369Q154 405 129 405Q107 405 92 377T69 316T57 280Q55 278 41 278H27Q21 284 21 287Z"></path><path stroke-width="1" id="E3-MJMAIN-22C5" d="M78 250Q78 274 95 292T138 310Q162 310 180 294T199 251Q199 226 182 208T139 190T96 207T78 250Z"></path><path stroke-width="1" id="E3-MJMAIN-31" d="M213 578L200 573Q186 568 160 563T102 556H83V602H102Q149 604 189 617T245 641T273 663Q275 666 285 666Q294 666 302 660V361L303 61Q310 54 315 52T339 48T401 46H427V0H416Q395 3 257 3Q121 3 100 0H88V46H114Q136 46 152 46T177 47T193 50T201 52T207 57T213 61V578Z"></path><path stroke-width="1" id="E3-MJMAIN-2212" d="M84 237T84 250T98 270H679Q694 262 694 250T679 230H98Q84 237 84 250Z"></path><path stroke-width="1" id="E3-MJMATHI-3F5" d="M227 -11Q149 -11 95 41T40 174Q40 262 87 322Q121 367 173 396T287 430Q289 431 329 431H367Q382 426 382 411Q382 385 341 385H325H312Q191 385 154 277L150 265H327Q340 256 340 246Q340 228 320 219H138V217Q128 187 128 143Q128 77 160 52T231 26Q258 26 284 36T326 57T343 68Q350 68 354 58T358 39Q358 36 357 35Q354 31 337 21T289 0T227 -11Z"></path><path stroke-width="1" id="E3-MJMAIN-2B" d="M56 237T56 250T70 270H369V420L370 570Q380 583 389 583Q402 583 409 568V270H707Q722 262 722 250T707 230H409V-68Q401 -82 391 -82H389H387Q375 -82 369 -68V230H70Q56 237 56 250Z"></path><path stroke-width="1" id="E3-MJMATHI-6B" d="M121 647Q121 657 125 670T137 683Q138 683 209 688T282 694Q294 694 294 686Q294 679 244 477Q194 279 194 272Q213 282 223 291Q247 309 292 354T362 415Q402 442 438 442Q468 442 485 423T503 369Q503 344 496 327T477 302T456 291T438 288Q418 288 406 299T394 328Q394 353 410 369T442 390L458 393Q446 405 434 405H430Q398 402 367 380T294 316T228 255Q230 254 243 252T267 246T293 238T320 224T342 206T359 180T365 147Q365 130 360 106T354 66Q354 26 381 26Q429 26 459 145Q461 153 479 153H483Q499 153 499 144Q499 139 496 130Q455 -11 378 -11Q333 -11 305 15T277 90Q277 108 280 121T283 145Q283 167 269 183T234 206T200 217T182 220H180Q168 178 159 139T145 81T136 44T129 20T122 7T111 -2Q98 -11 83 -11Q66 -11 57 -1T48 16Q48 26 85 176T158 471L195 616Q196 629 188 632T149 637H144Q134 637 131 637T124 640T121 647Z"></path></defs><g stroke="currentColor" fill="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><use xlink:href="#E3-MJMATHI-76" x="0" y="0"></use><g transform="translate(485,-150)"><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-67" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-65" x="480" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6E" x="947" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-65" x="1547" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-72" x="2014" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-61" x="2465" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-74" x="2995" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-65" x="3356" y="0"></use></g><use xlink:href="#E3-MJMAIN-28" x="3288" y="0"></use><use xlink:href="#E3-MJMAIN-5B" x="3678" y="0"></use><use xlink:href="#E3-MJMATHI-78" x="3956" y="0"></use><use xlink:href="#E3-MJMAIN-5D" x="4529" y="0"></use><use xlink:href="#E3-MJMAIN-29" x="4807" y="0"></use><use xlink:href="#E3-MJMAIN-3D" x="5475" y="0"></use><g transform="translate(6531,0)"><use xlink:href="#E3-MJMATHI-56" x="0" y="0"></use><g transform="translate(583,-150)"><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6D" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-61" x="878" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-78" x="1408" y="0"></use></g></g><use xlink:href="#E3-MJMAIN-22C5" x="8837" y="0"></use><use xlink:href="#E3-MJMAIN-28" x="9338" y="0"></use><g transform="translate(9727,0)"><g transform="translate(120,0)"><rect stroke="none" width="4436" height="60" x="0" y="220"></rect><g transform="translate(1153,676)"><use xlink:href="#E3-MJMAIN-31" x="0" y="0"></use><use xlink:href="#E3-MJMAIN-2212" x="722" y="0"></use><use xlink:href="#E3-MJMATHI-3F5" x="1723" y="0"></use></g><g transform="translate(60,-717)"><use xlink:href="#E3-MJMAIN-31" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6E" x="707" y="557"></use><use xlink:href="#E3-MJMAIN-2B" x="1247" y="0"></use><use xlink:href="#E3-MJMAIN-28" x="2248" y="0"></use><g transform="translate(2637,0)"><g transform="translate(120,0)"><rect stroke="none" width="524" height="60" x="0" y="220"></rect><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-78" x="84" y="583"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6B" x="110" y="-560"></use></g></g><g transform="translate(3402,0)"><use xlink:href="#E3-MJMAIN-29" x="0" y="0"></use><use transform="scale(0.707)" xlink:href="#E3-MJMATHI-6E" x="550" y="408"></use></g></g></g></g><use xlink:href="#E3-MJMAIN-2B" x="14626" y="0"></use><use xlink:href="#E3-MJMATHI-3F5" x="15627" y="0"></use><use xlink:href="#E3-MJMAIN-29" x="16033" y="0"></use></g></svg></span></span><script type="math/tex; mode=display" id="MathJax-Element-3"> |
Revision as of 05:33, 31 October 2017
Model
Introduction
In this model, we simplify the actual biology process into basic model that only remains input molecule, promotor, transcription gene, mRNA, goal protein and output molecule from both dynamic perspective and responding ability. In developed model, we consider different conditions including the population growth, diffusion of signal and decay of signal molecules in cells. which will have influence on our block. Finally, we completely construct the model of our block, which will instruct our experiment results and using of our system. Moreover, this model does some basic researches on population and new measurement methods.
Aim
- Develop the dynamic model of genetic expression, which consider the influence of population of E.coli, diffusion of signal molecule and decay of signal molecules.
- Solve the problem on parameter fitting in our experiments results.
- Give a measurement method on determing the efficiency of signal converter.
- Use both theoritical simulation and experiments results to indicate the main factor affecting the growth of E.coli.
Symbol
Symbol | Meaning |
---|---|
$v_{generate}$ | The generation efficency of mRNA |
$[X]$ | The concentration of substance $X$ |
$g_{X}$ | The generation rate of substance $X$ |
$\phi_{X}$ | The decay rate of substance $X$ |
$V_{\max}$ | The maximum rate of generation |
$C_{saturated}$ | The saturated concentration |
$N_{\max}$ | The maximum population |
$r$ | Growth rate of E.coli |
$[S]_t$ | Function of signal molecule decay |
$R(t)$ | Function of mRNA generate |
Assumption
- mRNA and proteins will decay following Poisson distribution (equivalent to birth-and-death process)
- All combinations of two proteins are considered as quick reactions (Only control by thermodynamics)
- The constitutive promoter has a constant rate to transcript proteins.
- All raw materials inside cells can be considered as constants.
Basic Model
$$ \begin{aligned} \frac{d([mRNA])}{dt}&=v_{generate}-\phi_{mRNA}[mRNA]\\ \frac{d([protein])}{dt}&=g_{protein}[mRNA]-\phi_{protein}[protein]\end{aligned} $$ In these equations, $v_{generate}$ refers to the efficiency of mRNA transcription. $\phi$ refers to the degradation rate of mRNA and protein.
The property of $v{generate}$ depends on the promoter and the concentration of inducer molecule. If the promoter is pcons, $v{generate}$ is a constant. Otherwise, it will have a sensitive response to different concentration of inducer molecule. This reponse can be expressed as following form:
$k$ refers to the dissociation constant and $x$ refers to the concentration of inducer concentration. $\epsilon$ refers to the leakage of genetic expression.
In comparision, for NOR GATE, the repression of inducer molecule can be expressed as similar form:
For specific concerntration, $v_{generate}$ is a constant, otherwise it is a function of $[x]$
The generated protein is used to produce new signal molecule, which play a role as enzyme. Different from Michaelis-Menten equation, our protein (in other words, enzyme) will degradate while producing new siginal molecule, So this fact should be considered into our fundmental model.
Mathematical expression for producing new signal molecule:
Developed Model
Growth of E.coli
In the developed model, we first take the growth of E.coli into consideration. The growth of E.coli can not only fluctuate the concentration of both reactants and products, but also an important variable in calculate final concentration of products. This model is based on this two fundamental relation:
Correspondingly, it is same to equation for mRNA expression:
$N{E.coli}$ is a function used to show the population of E.coli, $V{E.coli}$ refers to the volume of every E.coli, as a constant. So we can divide out the constant $V_{E.coli}$ on both sides of every equations, and take derivative formula:
Simplify this equation into following form:
$N_{E.coli}$ is satisfied to following equation:
$r$ refers to growth rate of E.coli and $N{\max}$ refers to the limits of E.coli population. Since $N{\max}$ and $N_{t=0}$are constants, so we define following parameter:
And $\frac{N'}{N}$ equals:
From our experiments, we find there are another two possible factors affecting the production of our system. First one is diffusion of signal molecule at initial time, the other one is the decay of signal molecule with the time flying.
Diffusion of signal molecule at initial time
The concentration of signal is always considered to diffuse into E.coli very rapidly. But from our data, we find that the initial part of our dynamic curve is not fitting to our basic model. Our basic model indicates that the rate of generating will decrease with the time flying, but the experiment shows that the velocity will have a short rise at initial time and then decrease as the way predicted by basic model. Therefore, we take process of diffusion into consideration. Because at very beginning, the concentration of signal in E.coli is very low, and then it will rise by diffusion, so the efficiency of production will rise according to time in a short time period.
We suppose the initial concentration difference between inside of E.coli and outside is $\Delta c(0)$, also we know the time for E.coli to balence this difference:
So the generating efficency comes to:
And we will use this formula to simulate initial state.
The demo is shown above which is a Log linear plot. X-axis refers to the time, Y-axis refers to the generating efficiency. We can easily figure out the concentration will rapidly get to steady state and remains to a constant. Therefore, it will only affect the inital transcription efficiency.
Decay of signal molecule
In basic model, we consider the decay of signal can be neglected because we found there's no significant difference between concentration in vitro. But actually when we meature the rough concentration in the LB with E.coli, we found that the concentration has a linear deacrease through time, which we should take consideration into our model.
The decay can be shown as following equation:
And the $v_{generate}$ becomes to:
To illustrate the change taken by the decompose of signal molecule, we can see following simulation curves:
X-axis refers to time. We find the efficiency will not be disturbed greatly at initial time, and will have a rapid decrease when the concentration equals to the half of origin. This property shows that we should control the reaction time otherwise the production will decay without production with the time going by. So the main purpose of this model is to predict when we dilute the input signal solution to obtain the maximum of protein to convert out signal.
Extra model
This part will discuss an interesting model on how the signal molecule affect the growth and population. The reason why we care about this question is that we measured the OD600 under different circumstance and found some special relation between the concentration and the population. In breif, with the rise of concentration, the population will decrease. We wonder the mechanism and propse two hypothesis:
The signal molecule is toxic to E.coli, so the population will decrease related to the increase of concentration linearly.
The signal molecule induce the synthesis of GFP which occupy the substance that is originally used for growth. It indicates that if the GFP is produced, then the population will be at low level, otherwise the population will be at normal level.
In our model, we indicates the second hypothesis is more realistic.
Model of parameter fitting and simulation
Hill equation
To get the parameter of Hill equation through our data, we tranfer Hill equation to following form:
In this form, we can get easily get a linear relation between our input concerntration and output GFP. The question is how to find out $V_{max}$ in this equation because this value determine the reprocessed data of output. Another question is, due to the large scale of our data, to ease the workload of proceesing such data. To meet the needs of these two question, first we let each output data substract the minimum among all output data, and define the ratio between each processed output data and the maximum of all output data as the standard output. (NOTICE: The minimum data of this output data set can be the control.)As following shows:
The elements in $SY_{output}$ fit following equation:
We define the value of $\frac{V{max}}{\max{Youtput}-\min{Y{output}}}$ as a parameter $PV_{max}$. So the equation we actually simulate is following one:
We use Mathematica as fitting tools, the following code is shown:
outputdata = {output1, output2, output3, output4, output5,output6};
Processeddata = (outputdata - Min[outputdata])/(Max[outputdata] -
Min[outputdata]) // N;
data' = {{Log10[10^(-9)], Processeddata[[1]]}, {Log10[10^(-8)],
Processeddata[[2]]}, {Log10[10^(-7)],
Processeddata[[3]]}, {Log10[10^(-6)],
Processeddata[[4]]}, {Log10[10^(-5)], Processeddata[[5]]},{Log10[10^(-4)], Processeddata[[6]]}};
data = {{data'[[1, 1]], data'[[1, 2]]}, {data'[[2, 1]],
data'[[2, 2]]}, {data'[[3, 1]], data'[[3, 2]]}, {data'[[4, 1]],
data'[[4, 2]]}, {data'[[5, 1]], data'[[5, 2]]}, {data'[[6, 1]], data'[[6, 2]]}};
solu = Flatten[
Solve[Log10[(y*PVmax)/(1 - (y*PVmax))] == n*x - n*logk, y]];
fitparameter = (FindFit[data, y /. solu, {PVmax, logk, n}, x])
fit = y /. solu /. fitparameter;
Show[ListPlot[data, PlotStyle -> Red], Plot[fit, {x, -10, 0}]]
Example and its output is shown (NOTICE: This example is the fitting curve of the Tra with its limited five data. Actually most of our data, except for tra, has six inputs and outputs, so the original code, which is shown above, has six outputs. When we use this code, we can just import outputs into "outputdata" list and run this programm. ):
outputdata = {16141, 6812, 32977, 362525, 959405};
Processeddata = (outputdata - Min[outputdata])/(Max[outputdata] -
Min[outputdata]) // N;
data' = {{Log10[10^(-9)], Processeddata[[1]]}, {Log10[10^(-8)],
Processeddata[[2]]}, {Log10[10^(-7)],
Processeddata[[3]]}, {Log10[10^(-6)],
Processeddata[[4]]}, {Log10[10^(-5)], Processeddata[[5]]}};
data = {{data'[[1, 1]], data'[[1, 2]]}, {data'[[2, 1]],
data'[[2, 2]]}, {data'[[3, 1]], data'[[3, 2]]}, {data'[[4, 1]],
data'[[4, 2]]}, {data'[[5, 1]], data'[[5, 2]]}};
solu = Flatten[
Solve[Log10[(y*PVmax)/(1 - (y*PVmax))] == n*x - n*logk, y]];
fitparameter = (FindFit[data, y /. solu, {PVmax, logk, n}, x])
fit = y /. solu /. fitparameter;
Show[ListPlot[data, PlotStyle -> Red], Plot[fit, {x, -10, 0}]]
Then we can get the meaningful parameter from these data quickly and easily.
Simulation of Signal Producing
The Efficiency of Signal Converter
How we can measure the working efficiency of our signal converter is an important question for us. As we all know, the reason why we use GFP to reflect the efficiency of promoter is that we can measure fluoresence easily and establish the quantity relationship between GFP expression and input signal concentration. But when it comes to some other products such as small molecule, they are hard to measure exactly. We use LC-MS to indicate the production of our signal converter roughly, but this data is too rough to instruct our following work. So we will use our model to obtain the parameter of converter indirectly by following experiments and deduction from model.
We symbol $S1,S2$ as the concentrations of two signal molecules, signal one and signal two, $GFP$ as the result of fluroesence intensity.
We propose two experiments. First one is using signal two to induce the expression of GFP. We take its results as standard curve. The other experiment is using signal one to obtain signal two, and we use signal two to induce the expression of gene. Also we will have following data:
From our model we know the relationship among $S1,S2$ and $GFP$ at steady state as following:
From the parameter fitting model, we can determine all parameters in $GFP-S_2$ curve. Therefore, we can use this curve and data of GFP from second experiment to obtain the input signal two concentration.
So we have the data $[S2]i$ related to input concentration of signal one, so we can get the relation through using parameter-fitting model would get the parameter of $S1-S2$ curve finally.
x-axis refers to Log of input signal molecular concentration; y-axis refers to the relative GFP expression.
x-axis refers to Log of signal one molecular concentration; y-axis refers to signal two molecular concentration. This curve indicates the effciency of signal converter, which low concentrations of input signal generate less output signal and high concentrations of input signal generate high output signal concentrations of input signal. And there exists a significant drop between low expression and high expression. It is absolutely what we want!
Rough schematic diagram
This is the concentration curve of protein related to time
This is the concentration curve of protein complex related to time
This is the concentration curve of producing signal molecule related to time
Simulation of NOR GATE
Rough schematic diagram
This is the concentration curve of produced signal molecule related to time
Theoretical Calculation of Modeling
Solution to ODE
The core of our model is to solve following equation and find parameters from experiments:
The solution can be decomposed to two parts:
From fisrt equation we will get:
How can we use the solution to first equation to solve second equation? The answer is to transfer constant $C$ into a function related to $t$. And the derivative will become to following formula:
Therefore, the solution to second equation is:
The difficulty is how we can use such a complex function in next differential equation? Actually we probably cannot get the analytic result of the integral, so it seems impossible to get an exact function for protein concentration. Fortunately, there are still some special properties in our function which wll help us to get a relative solution.
We start from the function of mRNA. Since $P(t)$ is a constant in our first equation, we can directly give the result:
Now we solve following differetial equation:
Or for simplicity, we use:
According to the differential operator method, we get:
For $R(t)$, we write the general form:
When we take derivation:
Furthermore:
REMARK:
Therefore we get:
The first summation is simple:
Second summation is really complex, so we must do some approximation:
Therefore we get a approximation of protein's concentration:
Solution to Our Model
Details of Developed Model
Growth of E.coli
We combine this solution with our equation, and then we get:
We suppose that:
Therefore we get:
As a special case, this is used to decribe if the growth of E.coli is at a steady state:
Then we get a simple formula:
Further more, we define:
Consider the inital value of mRNA, we get following relation:
Now let's have a look on this special function and related integration:
We can hardly get an analytic solution to this integration theoritically, but we can do some transformation on $N_c(t)$, which helps us solve this problem partly according to this fact:
So we suppose:
From the biological perspective, this indicates the initial population of E.coli has been more than the half of maximum population, this assumption roughly fits our experiments. This condition promises following equation:
So we will have:
And:
Therefore:
Before we use this formula to obtain the expression of protein's concentration, we should analyze and simplify it.
Property i :
For the first part:
For the second part:
Therefore:
Property ii :
So we finally get:
Now we use this formula to solve following ODE:
From previous calculate we could guess the approximate solution to protein's concentration will be following form:
Or we can appromixately consider this formula as:
$\kappa$ is a parameter used to reflect the fact comprehensively.
Finally we get:
This result indicates the generated protein concentration has a direct relation with input signal molecule concentration. More importantly, we use Hill equation to describe the final product concentration induced by different concentration of input signal molecule is approperiate.
In our case, after renewing with fresh LB solution, the protein will degradate and never generate new. So another dofferential equation is needed to describe this situation:
The initial value of this equation is:
Then the function will be:
Diffusion of signal molecule at initial time
Review
We suppose the initial concentration difference between inside of E.coli and outside is $\Delta c(0)$, also we know the time for E.coli to balence this difference:
So the generating efficency comes to:
And we will use this formula to give the initial state.
How to solve?
First we have following relations in mathematics:
These two equation indicate a group of equivalent infinitesimal, which we can use to do approximation in our problem. The approximation can be done as following way by using two properties:
For simplicity, we can rewrite into a simple equation:
And the ODE for mRNA can be written into:
Solution:
Correspondingly, the function of protein is:
The simulation curve for an arbitraty number:
We can see the initial slope of the curve is rasing to a point and then decrease gradually which is highly fixed to the experiment result we get.
Decay of signal molecule
Review
In basic model, we consider the decay of signal can be neglected because we found there's no significant difference between concentration in vitro. But actually when we meature the rough concentration in the LB with E.coli, we found that the concentration has a linear deacrease through time, which we should take consideration into our model.
The decay can be shown as following equation:
And the $v_{generate}$ becomes to:
According to the solution we deduced before, we have:
Surely the first step is to confirm this equation gives a reasonable result. Through using following mathematics conclution, we can approximately consider the integral as a summation:
We assume $a=0$ which has no effect to the formula but has its biological meaning, which is the starting timepoint. So we have:
Which
We use matlab to obtain a rough curve. X-axis refers to time.
This is a important result because it indicates that the production will not always increase with the time going. Actually, there exists a so-called "best time" to process next step in our system. For example, this peak can determine when we dilute input signal to get output signal as much as possible.
Red stars refers to "best time" according to different input concentration from upstream block.
*matlab code:
n = [];
fn = [];
for i=1:T/dt
n = [n i];
t = exp(-a*i*dt);
sum=0;
for j=0:i
sum = sum + (Vm-(j*dt)^n)*exp(a*dt*j)*dt/(k^n+(Vm-(dt*j)^n));
end
y = t*sum+\phi* (Vm - dt*i)^(n-1)/(k^n + (Vm - dt*i)^n)^2;
fn = [fn y];
end
plot(n,fn);
max(fn);
This matlab code shows how we draw the curves and how to find maximum.
Signal Producing
Review
In last part, we gives a approximate value of the protein we will get from our system:
If we consider the decay of molecule, then we rewrite equation above as:
Which:
For simpilicity, we define the final production of goal protein as
Analyse
Now we focus on the differential equation related to the signal production:
In this equation set, $[E]$ equals to the concentration of protein.
Finally we have:
And the initial state:
Therefore:
Finally we get:
NOR Gate
This result can easily transit to NOR gate, because from mathematical perspective, the different places are initial values and another form of Hill equation. To describe the mechanism of NOR gate, we supposed that the whole system remains at steady state. (In other word, all concentrations remain as constants.)
We get:
Furthermore we get:
With the relation:
Also we have:
Extra model
Review
Model of E.coli population:
$N_{E.coli}$ is satisfied to following equation:
$r$ refers to growth rate of E.coli and $N{\max}$ refers to the limits of E.coli population. Since $N{\max}$ and $N_{t=0}$are constants, so we define following parameter:
Two hypothesis:
- The signal molecule is toxic to E.coli, so the population will decrease related to the increase of concentration linearly.
- The signal molecule induce the synthesis of GFP which occupy the substance that is originally used for growth. It indicates that if the GFP is produced, then the population will be at low level, otherwise the population will be at normal level.
Analyse
To show the difference between these two hypothesis, we give following equation:
Hypothesis 1:
$\gamma$ refers to the death rate caused by toxic substance,$[S]$ refers to the concentration of signal molecule and $[S]_{critical}$ refers to the critical point which means all E.coli are dead:
Therefore:
X-axis refers to the time and Y-axis refers to the growth curves. Different curves refer to different concentrations.
Hypothesis 2:
$\beta$ refers to the ratio of limiting the growth of E.coli, which fits to following equation:
The reason we use the efficiency of mRNA generation is because this ratio determines how many GFP will be finally produced. For example, if the ratio is high, the production of GFP will be at high level, which also means the most of substance are used to produce GFP instead of growth of E.coli.
Therefore:
X-axis refers to the time and Y-axis refers to the growth curves. Different curves refer to different concentrations. Low concentration refers to high population and high concentration refers to low population.
From our data, we found the result showed that hypothesis two was more realistic.
The experiment shows an obvious difference between low concentration and high concentration which fitts to the hypothesis two.
But we also cannot eliminate the hypthesis one, because the curves of low concentration go to steady state but the high concentration go slightly down. If we use hypothesis two to explain this phenomemon, that is: The production of GFP highly occupy the resource and leave little resource for the growth of E.coli even cannot mantain the population at the steady state. If we use hypothesis one, then the result is obvious that signal molecule is toxic to E.coli which causes unavoidable death of E.coli. So further study is required.