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1.
Chemosphere ; 336: 139284, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37348613

RESUMO

Selenastrum capricornutum efficiently degrades benzo(a)pyrene (BaP) but few proteins related to BaP degradation have been identified in this microalgae. So far, it has only been suggested that it could degrade BaP via the monooxygenase and/or dioxygenase pathways. To know more about this fact, in this work, cultures of S. capricornutum incubated with BaP were used to obtain the molecular weights (MWs) of proteins existing in its extra- and cellular extracts by electrophoresis and UPLC-ESI(+)-TOF MS analysis. The results of this proteomic approach indicated that BaP markedly induces the MWs: 6-20, 30, 45, and 65 kDa in cells; 6-20, 30.3, 38-45, and 55 kDa in liquid medium. So, these proteins could be related to BaP biodegradation. An identified protein with monooxygenase activity and rubredoxins (Rds) show to be related to BaP degradation: Rds could participate, together with the monooxygenase in the electron transfer during the formation of monohydroxylated-BaP metabolites. Rds may be also associated with a dioxygenase system that degrades BaP to form dihydrodiol-BaP metabolites. A multi-pass membrane protein was identified too, and it can regulate the transport of molecules like enzymes from inside the cell to the outside environment. At the same time, the presence of a dihydrolipoamide acetyltransferase validated the stress caused by the exposure to BaP. It is noteworthy that these findings provide valuable and original information on the characterization of the proteins of S. capricornutum cultures degrading BaP, whose enzymes have so far not been known. It is important to highlight that the functions of the identified proteins can help in understanding the metabolic and environmental behavior of this microalgae, and the extracts containing the degrading enzymes could be utilized in bioremediation applications.


Assuntos
Clorofíceas , Clorófitas , Dioxigenases , Clorófitas/metabolismo , Benzo(a)pireno/metabolismo , Proteômica , Clorofíceas/metabolismo , Oxigenases de Função Mista/metabolismo , Dioxigenases/metabolismo , Espectrometria de Massas
2.
Drug Dev Ind Pharm ; 46(12): 2041-2050, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33121271

RESUMO

OBJECTIVE: The present investigation was aimed to evaluate the hepatoprotective potential of ethanolic extract of Psidium guajava (P. guajva) and its isolated quercetin fraction on carbon tetrachloride (CCl4)-induced hepatotoxicity. MATERIALS AND METHODS: The rats were divided into 6 groups and each group contained 6 rats. CCl4 (1.5 ml/kg b.w.) was used to induce the hepatotoxicity. Ethanolic extract of P. guajava (300 mg/kg b.w.), isolated quercetin fraction (20 mg/kg b.w.) were used as a treatment and silymarin (25 mg/kg b.w.) was used as a standard drug. After the study period, the liver tissues were collected and evaluate the levels of liver functional markers, mitochondrial enzymes, histopathological analysis and the expressions of inflammatory markers. RESULTS: The levels of liver functional markers were increased and protein, albumin and A/G ratio levels were decreased and the decreased levels of mitochondrial enzymes were noted in CCl4-induced rats and the levels were restored near to normal significantly when the administration ethanolic extract of P. guajava, isolated quercetin fraction and silymarin. The normal architecture of liver tissues were altered and the mRNA expressions were up-regulated in CCl4-induced rats and the liver tissues were normalized and the mRNA and protein expressions were down-regulated near to normal significantly when the administration of ethanolic extract of P. guajava, isolated quercetin fraction and silymarin. CONCLUSION: From these results, the isolated quercetin fractions have better activity than that of the ethanolic extract of P. guajava leaves. Hence, the isolated quercetin may be used as the safest drug for hepatotoxicity in future.


Assuntos
Tetracloreto de Carbono/química , Doença Hepática Induzida por Substâncias e Drogas , Psidium , Silimarina , Animais , Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Fígado , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Ratos , Silimarina/farmacologia
3.
PeerJ ; 8: e9202, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32509464

RESUMO

BACKGROUND: Bisphosphonate therapy has become a popular treatment for osteoporosis, Paget's disease, multiple myeloma, osteogenesis imperfecta, myocardial infarction, and cancer despite its serious side effects. Bisphosphonate-induced molecular signaling changes in cells are still not clearly elucidated. METHODS: As bisphosphonates are primarily engulfed by macrophages, we treated RAW 264.7 cells (a murine macrophage cell line) with pamidronate and investigated global protein expressional changes in cells by immunoprecipitation high performance liquid chromatography (IP-HPLC) using 218 antisera. RESULTS: Pamidronate upregulated proliferation-activating proteins associated with p53/Rb/E2F and Wnt/ß-catenin pathways, but downregulated the downstream of RAS signaling, pAKT1/2/3, ERK-1, and p-ERK-1, and subsequently suppressed cMyc/MAX/MAD network. However, in situ proliferation index of pamidronate-treated RAW264.7 cells was slightly increased by 3.2% vs. non-treated controls. Pamidronate-treated cells showed increase in the expressions of histone- and DNA methylation-related proteins but decrease of protein translation-related proteins. NFkB signaling was also suppressed as indicated by the down-regulations of p38 and p-p38 and the up-regulation of mTOR, while the protein expressions related to cellular protection, HSP-70, NRF2, JNK-1, and LC3 were upregulated. Consequently, pamidronate downregulated the protein expressions related to immediate inflammation,cellular differentiation, survival, angiogenesis, and osteoclastogenesis, but upregulated PARP-1 and FAS-mediated apoptosis proteins. These observations suggest pamidronate affects global protein expressions in RAW 264.7 cells by stimulating cellular proliferation, protection, and apoptosis but suppressing immediate inflammation, differentiation, osteoclastogenesis, and angiogenesis. Accordingly, pamidronate appears to affect macrophages in several ways eliciting not only its therapeutic effects but also atypical epigenetic modification, protein translation, RAS and NFkB signalings. Therefore, our observations suggest pamidronate-induced protein expressions are dynamic, and the affected proteins should be monitored by IP-HPLC to achieve the therapeutic goals during treatment.

4.
Biochem Biophys Res Commun ; 525(4): 921-927, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32173524

RESUMO

Although several studies have implied that a hypoxic environment may be a factor that influences muscle hypertrophy, scant attention has been paid to the effect of oxygen molecules on the morphological characteristics of muscle. The purpose of the present study was to examine the effect of semisevere (i.e., 5%) to moderate (i.e., 10% or 15%) hypoxic environments on the morphological characteristics of skeletal muscle and the associated mechanisms. C2C12 skeletal muscle cells were divided into various groups, namely, the normoxia group (20.9% O2) and hypoxia groups (5% O2, 10% O2, and 15% O2), and cell growth and the expression of associated proteins in the hypoxia groups were compared with those in the normoxia group. The myotube diameter and cell differentiation index were determined on day 6 by immunocytochemical analyses. The expression of proteins associated with muscle cell differentiation (MyoD and myogenin) and muscle hypertrophy (mTOR and p70s6K) were analyzed by Western blotting. We found that compared with normoxia, a 5% oxygen environment inhibited differentiation and caused muscle atrophy. However, compared with normoxia, a 10% oxygen environment promoted muscle differentiation, and 10% oxygen and 15% oxygen environments induced muscle hypertrophy. Compared with normoxia, a 10% oxygen environment promoted myogenin and the expression of mTOR, p70s6K, and the metabolic signal AMPK. We concluded that a hypoxic environment, if not too severe, may promote muscle differentiation and hypertrophy by increasing the expression of proteins associated with muscle cell differentiation and hypertrophy.


Assuntos
Músculo Esquelético/patologia , Animais , Diferenciação Celular/efeitos dos fármacos , Hipóxia Celular , Linhagem Celular , Proliferação de Células , Camundongos , Músculo Esquelético/crescimento & desenvolvimento , Músculo Esquelético/metabolismo , Proteína MyoD/metabolismo , Mioblastos Esqueléticos/metabolismo , Mioblastos Esqueléticos/patologia , Miogenina/metabolismo , Oxigênio/metabolismo , Oxigênio/farmacologia , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Serina-Treonina Quinases TOR/metabolismo
6.
Dose Response ; 17(3): 1559325819871755, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31516401

RESUMO

The aim of the current study is to assess the effectiveness of milk thistle seeds (Mth) in combination with Taraxacum officinale (Tof) and/or Camellia sinensis (Csin) against tetrachloromethane (Tcm) renotoxicity in rats. Tetrachloromethane was injected in a single dose, followed by 1-month treatments with Mth, Tof, and Csin alone or in combination. Serum urea, uric acid, and creatinine levels were significantly increased matched with the control group. Masson trichrome stain revealed increase in the deposition of fibrous tissue in the interstitium between the tubules and the renal corpuscles. Immunohistochemical analysis of kidney tissues revealed that Tcm induced an increase in the immune response of tumor growth factor ß (TGF-ß) and Janus kinase (JAK) protein expressions and cysteine-aspartic acid protease 3 (caspase 3), while B-cell lymphoma 2 (Bcl2) was downregulated. Treatment with the antioxidants in question either alone or in combination ameliorated all kidney function parameters and showed mild immune reactivity toward TGF-ß and JAK protein expressions in blood vessels and glomeruli in the kidney tissues and downregulated caspase 3 and activated Bcl2 protein expression. The combination regimen of the 3 antioxidants showed the most significant renoprotective effect. This was also confirmed histopathologically. It was concluded that the antioxidant mixture is considered as a promising candidate toward renal dysfunction and immune reactivity induced by Tcm and other toxicants.

7.
DNA Cell Biol ; 38(9): 955-961, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31361513

RESUMO

The chromatin-remodeling complex ATRX/DAXX is one of the major epigenetic factors that controls heterochromatin maintenance due to its role in histone deposition. ATRX is involved in nucleosome configuration and maintenance of higher order chromatin structure, and DAXX is a specific histone chaperone for H3.3 deposition. Dysfunctions in this complex have been associated with telomere shortening, which influences cell senescence. However, data about this complex in brain tissue related to aging are still scarce. Therefore, in the present study, we analyzed ATRX and DAXX expressions in autopsied human brain specimens and the telomere length. A significant decrease in gene and protein expressions was observed in the brain tissues from the elderly compared with those from the young, which were related to short telomeres. These findings may motivate further functional analysis to confirm the ATRX-DAXX complex involvement in telomere maintenance and brain aging.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Envelhecimento/genética , Encéfalo/metabolismo , Proteínas Nucleares/genética , Proteína Nuclear Ligada ao X/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/crescimento & desenvolvimento , Proteínas Correpressoras , Humanos , Pessoa de Meia-Idade , Chaperonas Moleculares , Proteínas Nucleares/metabolismo , Homeostase do Telômero , Proteína Nuclear Ligada ao X/metabolismo
8.
J Cancer Res Ther ; 15(2): 426-436, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30964122

RESUMO

AIMS AND METHODS: Retrospectively, this paper compared the differences of the Epstein-Barr virus (EBV)-encoded small RNAs (EBERs), protein expression and gene mutations of tumor suppressor gene p53 (TP53) in keratinized nasopharyngeal squamous cell carcinoma (KNSCC) and nonKNSCC, and the relationships between pathological features and the prognosis of patients were analyzed. RESULTS: The positive rate of EBERs hybridization and TP53 expressions was 76.3% and 52.2%, respectively, while the mutation rate of TP53 gene was 39.6%. Logistic regression analysis showed direct relationships between the subtypes of nasopharyngeal squamous cell carcinoma (NPSCC) and EBERs-positive, or frequent consumption of pickled food. Overall survival rates of patients with positive TP53 expression, the TP53 gene mutations, vascular invasions, organ metastases, lymph node metastasis, and clinical recurrence were significantly lower than those of patients without those symptoms. The poorer prognosis was related to regularly drinking and the advanced age. According to the Cox regression analysis, we found that the main prognostic factors of NPSCC patients were the aging, recurrence, TP53 gene mutations, especially exon 7 or 8 mutations. CONCLUSIONS: We concluded that there were the correlations between NPSCC subtypes with EBV infection and frequent intaking of pickled food, while aging, clinical recurrence, and TP53 gene mutations were independent predictors for the poor prognosis of nasopharyngeal carcinoma.


Assuntos
Carcinoma de Células Escamosas/etiologia , Carcinoma de Células Escamosas/mortalidade , Infecções por Vírus Epstein-Barr/complicações , Herpesvirus Humano 4 , Neoplasias Nasofaríngeas/etiologia , Neoplasias Nasofaríngeas/mortalidade , Proteína Supressora de Tumor p53/genética , Adulto , Idoso , Biomarcadores Tumorais , Carcinoma de Células Escamosas/diagnóstico , Linhagem Celular Tumoral , Suscetibilidade a Doenças , Infecções por Vírus Epstein-Barr/virologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Hibridização In Situ , Masculino , Pessoa de Meia-Idade , Mutação , Neoplasias Nasofaríngeas/diagnóstico , Gradação de Tumores , Prognóstico , Recidiva , Fatores de Risco , Carga Tumoral
9.
Open Access Maced J Med Sci ; 7(22): 3733-3736, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32127964

RESUMO

AIM: The objective of the study was to evaluate protein expression in NIH 3T3 cells that are treated with virgin coconut oil (VCO) and hydrolysed of virgin coconut oil (HVCO) in vitro. METHODS: Coconut oil used in this study was virgin coconut oil (VCO) and VCO hydrolysed by Rhizomucor miehei (HVCO). NIH 3T3 cells (5x105 cells/well) were seeded in nine wells and incubated for overnight, then divided into three groups. Each group consisted of three wells. Group one without treatment, group two added VCO, and group three added HVCO and then incubated for overnight. One well in each group was added MMP-9, PDGF-BB, and TGF-ß1 and incubated one hour. Finally, expressions of MMP-9, PDGF-BB, and TGF-ß1 were detected using immunocytochemistry method. RESULTS: The results of the study showed that VCO and HVCO increased protein expressions of MMP-9, PDGF-BB, and TGF-ß1. Percentage of MMP-9 expressions treated by VCO increased from 2.89 ± 0.07 to 28.16 ± 0.34, PDGF-BB from 28.11 ± 0.13 to 48.53 ± 0.49, and TGF-ß1 from 4.19 ± 0.08 to 18.41 ± 0.54. Percentage of MMP-9 expressions treated by HVCO increased from 2.89 ± 0.07 to 55.40 ± 0.94, PDGF-BB from 28.11 ± 0.13 to 61.65 ± 0.42, and TGF-ß1 from 4.19 ± 0.08 to 36.35 ± 0.67. CONCLUSION: VCO and HVCO increase the expression of MMP-9, PDGF-BB, dan TGF-ß1 in NIH3T3 cells and therefore, coconut oil active in the wound healing process. HVCO is more than active than VCO.

10.
Maxillofac Plast Reconstr Surg ; 40(1): 44, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30613574

RESUMO

BACKGROUND: Coffee extract has been investigated by many authors, and many minor components of coffee are known, such as polyphenols, diterpenes (kahweol and cafestol), melanoidins, and trigonelline, to have anti-inflammatory, anti-oxidant, anti-angiogenic, anticancer, chemoprotective, and hepatoprotective effects. Therefore, it is necessary to know its pharmacological effect on hepatocytes which show the most active cellular regeneration in body. METHODS: In order to determine whether coffee extract has a beneficial effect on the liver, 20 C57BL/6J mice were intraperitoneally injected once with dialyzed coffee extract (DCE)-2.5 (equivalent to 2.5 cups of coffee a day in man), DCE-5, or DCE-10, or normal saline (control), and then followed by histological observation and IP-HPLC (immunoprecipitation high performance liquid chromatography) over 24 h. RESULTS: Mice treated with DCE-2.5 or DCE-5 showed markedly hypertrophic hepatocytes with eosinophilic cytoplasms, while those treated with DCE-10 showed slightly hypertrophic hepatocytes, which were well aligned in hepatic cords with increased sinusoidal spaces. DCE induced the upregulations of cellular proliferation, growth factor/RAS signaling, cellular protection, p53-mediated apoptosis, angiogenesis, and antioxidant and protection-related proteins, and the downregulations of NFkB signaling proteins, inflammatory proteins, and oncogenic proteins in mouse livers. These protein expression changes induced by DCE were usually limited to the range ± 10%, suggesting murine hepatocytes were safely reactive to DCE within the threshold of physiological homeostasis. DCE-2.5 and DCE-5 induced relatively mild dose-dependent changes in protein expressions for cellular regeneration and de novo angiogenesis as compared with non-treated controls, whereas DCE-10 induced fluctuations in protein expressions. CONCLUSION: These observations suggested that DCE-2.5 and DCE-5 were safer and more beneficial to murine hepatocytes than DCE-10. It was also found that murine hepatocytes treated with DCE showed mild p53-mediated apoptosis, followed by cellular proliferation and growth devoid of fibrosis signaling (as determined by IP-HPLC), and subsequently progressed to rapid cellular regeneration and wound healing in the absence of any inflammatory reaction based on histologic observations.

11.
Cell Physiol Biochem ; 42(4): 1623-1634, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28738356

RESUMO

BACKGROUND/AIMS: The study aims to determine the effects of thermal preconditioning on tendon adhesion by regulating the expression of heat shock protein 72 (HSP72) in rat models. METHODS: Sixty male Wistar rats were collected and randomly assigned into the thermal preconditioning and control groups. During the 4th and 8th weeks following surgery, 15 rats were sacrificed in each period respectively, and their tendon adhesion was observed and evaluated. Biomechanical testing was performed to measure the tensile strength and gliding distance of tendons. Hematoxylin-eosin (HE) was used to observe the morphological structure of the tendons. Immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to detect the HSP72, fibroblast growth factor-2 (FGF-2), fibroblast growth factor receptor-1 (FGFR-1), ß-catenin, epithelial cell adhesion molecule (EPCAM), Tenomodulin and scleraxis protein expressions. Pearson correlation analysis was applied to analyze the correlation between HSP72 expression and tendon adhesion. RESULTS: At the 4th week after surgery, we found no differences in the tendon adhesion scores or mRNA and protein expressions of HSP72 between the thermal preconditioning and control groups. However, after the 8th week after surgery, the thermal preconditioning group had a lower tendon adhesion score and higher mRNA and protein expressions of HSP72 than the control group. During the same period, we found longer gliding distance and higher expression levels of FGF-2, FGFR-1, ß-catenin, Tenomodulin and scleraxis, but lower EPCAM expression in the thermal preconditioning group. Pearson correlation analysis indicated that HSP72 mRNA and protein expression levels were negatively correlated with tendon adhesion. CONCLUSIONS: These findings provide evidence that thermal preconditioning may alleviate tendon adhesions via upregulation of HSP72 expression.


Assuntos
Proteínas de Choque Térmico HSP72/genética , Hipertermia Induzida/métodos , Tendões/metabolismo , Aderências Teciduais/genética , Aderências Teciduais/prevenção & controle , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fator 2 de Crescimento de Fibroblastos/genética , Fator 2 de Crescimento de Fibroblastos/metabolismo , Regulação da Expressão Gênica , Proteínas de Choque Térmico HSP72/agonistas , Proteínas de Choque Térmico HSP72/metabolismo , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Ratos , Ratos Wistar , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Tendões/cirurgia , Resistência à Tração , Aderências Teciduais/metabolismo , beta Catenina/genética , beta Catenina/metabolismo
12.
Cytotechnology ; 68(3): 429-41, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-25371010

RESUMO

Advancements in cell cultures are occurring at a rapid pace, an important direction is culturing cells in 3D conditions. We demonstrate the usefulness of agarose hydrogels in obtaining 3 dimensional aggregates of three cell lines, A549, MCF-7 and Sp2/0. The differences in culture phases, susceptibility to cisplatin-induced cytotoxicity are studied. Also, the 3D aggregates of the three cell lines were reverted into 2D cultures and the protein profile differences among the 2D, 3D and revert cultures were studied. The analysis of protein profile differences using UniProt data base further augment the usefulness of agarose hydrogels for obtaining 3D cell cultures.

13.
Int J Clin Exp Pathol ; 8(3): 2737-45, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26045779

RESUMO

We aimed to investigate the role of Notch1/Hes signaling pathway in the pathogenesis of abnormal ossification of hip ligament in patients with ankylosing spondylitis (AS). 22 AS patients scheduled for artificial hip arthroplasty were randomly chosen as AS group. As controls, we used 4 patients diagnosed with transcervical fracture who underwent hip replacement surgery. Notch1 and Hes mRNA expressions were detected by real-time fluorescent quantitative polymerase chain reaction (RFQ-PCR). Immunohistochemistry (IHC) was used to detect Notch1 and Hes protein expression. Correlation analyses of Notch-l and Hes with AS-related clinical factors were conducted with spearman's correlation analysis and partial correlation analysis. RFQ-PCR results showed significant differences in Notch1 and Hes mRNA expressions between AS group and the control group (all P<0.05). IHC analysis further indicated positive nuclear signals of Notch1 and Hes protein, indicating functional activation of the Notch1 and Hes pathways. Semi-quantitative IHC showed a higher Notch1 and Hes expression levels in AS group compared to the control group (all P<0.05). Correlation analysis suggested that Hes protein expression was positively associated with the clinical course of the disease in AS patients. In conclusion, Notch1 and Hes overexpression was clearly detected in hip joint ligaments of AS patients, Hes protein expression was associated with the clinical course of AS. Taken together, we suggest that signaling pathways mediated by Notch1-Hes may contribute to ligament ossification of hip joints in AS patients.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/análise , Articulação do Quadril/química , Proteínas de Homeodomínio/análise , Ligamentos Articulares/química , Receptor Notch1/análise , Transdução de Sinais , Espondilite Anquilosante/metabolismo , Adulto , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Estudos de Casos e Controles , Feminino , Articulação do Quadril/patologia , Proteínas de Homeodomínio/genética , Humanos , Imuno-Histoquímica , Ligamentos Articulares/patologia , Masculino , Pessoa de Meia-Idade , Ossificação Heterotópica , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Receptor Notch1/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Espondilite Anquilosante/diagnóstico , Espondilite Anquilosante/genética
14.
Proc Natl Acad Sci U S A ; 110(46): 18531-6, 2013 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-24167288

RESUMO

Cell-to-cell variations in protein abundance in clonal cell populations are ubiquitous in living systems. Because protein composition determines responses in individual cells, it stands to reason that the variations themselves are subject to selective pressures. However, the functional role of these cell-to-cell differences is not well understood. One way to tackle questions regarding relationships between form and function is to perturb the form (e.g., change the protein abundances) and observe the resulting changes in some function. Here, we take on the form-function relationship from the inverse perspective, asking instead what specific constraints on cell-to-cell variations in protein abundance are imposed by a given functional phenotype. We develop a maximum entropy-based approach to posing questions of this type and illustrate the method by application to the well-characterized chemotactic response in Escherichia coli. We find that full determination of observed cell-to-cell variations in protein abundances is not inherent in chemotaxis itself but, in fact, appears to be jointly imposed by the chemotaxis program in conjunction with other factors (e.g., the protein synthesis machinery and/or additional nonchemotactic cell functions, such as cell metabolism). These results illustrate the power of maximum entropy as a tool for the investigation of relationships between biological form and function.


Assuntos
Proteínas de Bactérias/metabolismo , Quimiotaxia/fisiologia , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Escherichia coli/fisiologia , Proteínas de Membrana/metabolismo , Modelos Biológicos , Transdução de Sinais/fisiologia , Fenômenos Biofísicos , Entropia , Proteínas Quimiotáticas Aceptoras de Metil
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