Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 90
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
PLoS Genet ; 20(6): e1011335, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38913742

RESUMEN

The outer membrane of gram-negative bacteria is a barrier to chemical and physical stress. Phospholipid transport between the inner and outer membranes has been an area of intense investigation and, in E. coli K-12, it has recently been shown to be mediated by YhdP, TamB, and YdbH, which are suggested to provide hydrophobic channels for phospholipid diffusion, with YhdP and TamB playing the major roles. However, YhdP and TamB have different phenotypes suggesting distinct functions. It remains unclear whether these functions are related to phospholipid metabolism. We investigated a synthetic cold sensitivity caused by deletion of fadR, a transcriptional regulator controlling fatty acid degradation and unsaturated fatty acid production, and yhdP, but not by ΔtamB ΔfadR or ΔydbH ΔfadR. Deletion of tamB recuses the ΔyhdP ΔfadR cold sensitivity further demonstrating the phenotype is related to functional diversification between these genes. The ΔyhdP ΔfadR strain shows a greater increase in cardiolipin upon transfer to the non-permissive temperature and genetically lowering cardiolipin levels can suppress cold sensitivity. These data also reveal a qualitative difference between cardiolipin synthases in E. coli, as deletion of clsA and clsC suppresses cold sensitivity but deletion of clsB does not. Moreover, increased fatty acid saturation is necessary for cold sensitivity and lowering this level genetically or through supplementation of oleic acid suppresses the cold sensitivity of the ΔyhdP ΔfadR strain. Together, our data clearly demonstrate that the diversification of function between YhdP and TamB is related to phospholipid metabolism. Although indirect regulatory effects are possible, we favor the parsimonious hypothesis that YhdP and TamB have differential phospholipid-substrate transport preferences. Thus, our data provide a potential mechanism for independent control of the phospholipid composition of the inner and outer membranes in response to changing conditions based on regulation of abundance or activity of YhdP and TamB.


Asunto(s)
Proteínas de Escherichia coli , Fosfolípidos , Fosfolípidos/metabolismo , Fosfolípidos/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Transporte Biológico/genética , Cardiolipinas/metabolismo , Cardiolipinas/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Frío , Escherichia coli K12/genética , Escherichia coli K12/metabolismo , Regulación Bacteriana de la Expresión Génica , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Ácidos Grasos/metabolismo , Proteínas de Transferencia de Fosfolípidos/genética , Proteínas de Transferencia de Fosfolípidos/metabolismo
2.
Artículo en Inglés | MEDLINE | ID: mdl-37910294

RESUMEN

Cancer is a major public health concern because it is one of the main causes of morbidity and mortality worldwide. As a result, numerous studies have reported the development of new therapeutic compounds with the aim of selectively treating cancer while having little negative influence on healthy cells. In this context, earthworm coelomic fluid has been acknowledged as a rich source of several bioactive substances that may exhibit promising anticancer activity. Therefore, the objective of the present review is to evaluate the findings of the reported studies exploring the antitumor effects of coelomic fluid in the context of its possible utilization as a natural therapeutic agent to cure different types of cancer. The possible mechanisms underlying the coelomic fluid's anticancerous potential as well as the possibility for future development of cutting-edge therapeutic agents utilizing coelomic fluid-derived natural bioactive compounds to treat cancer disorders have been discussed along with future challenges. In addition, the feasibility of encapsulation of bioactive compounds derived from coelomic fluid with nanomaterials that could be further explored to attain more effective anticancer competence is discussed.

3.
Endocr Pract ; 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39025301

RESUMEN

OBJECTIVE: In male congenital hypogonadotropic hypogonadism (CHH), it was observed that lower dose human gonadotropic hormone (hCG) can maintain normal intratesticular testosterone levels. We propose this study to compare the low-dose hCG, follicle stimulating hormone (FSH), and Testosterone (T) [LFT Regimen] to conventional treatment to induce virilization and fertility. DESIGN: This open-label randomized pilot study was conducted from June 2020 to December 2021. SUBJECTS AND OUTCOME MEASURES: CHH were randomly assigned to either the LFT regimen (Group A)-low-dose hCG (500U thrice per week), FSH (150U thrice per week), and T(100 mg biweekly) or conventional therapy(GroupB) with high hCG dose(2000U thrice per week) and the same FSH dose. The hCG dosage was titrated to reduce anti-mullerian hormone (AMH) by 50% and normalization of plasma T in groups A and B, respectively. The primary objective was to compare the percentage of individuals who achieved spermatogenesis between the two groups. RESULTS: Out of 30 patients, 23 (76·7%) subjects achieved spermatogenesis, and the median time was 12 (9-14·9) months. There was no difference in achieving spermatogenesis between the two groups (64·3% vs 7·5%,P = 0·204), and even the median time for spermatogenesis was similar (15months vs 12months,P = 0·248). Both groups had nonsignificant median plasma AMH at spermatogenesis, [6·6 ng/ml (3·3-9·76) vs4·41 ng/ml (2·3-6·47), P = 0·298]. Similarly, the median plasma Inhibin B at spermatogenesis between groups were comparable [152·4 pg/ml (101·7-198·0) vs49·1 pg/ml (128·7-237·3), P = 0·488]. CONCLUSIONS: A reasonable approach to induce fertility in male CHH is to initiate combination therapy using FSH, low-dose hCG targeting AMH <6·9 ng/ml, along with T to achieve normal range. Monitoring AMH could serve as a proxy indicator of spermatogenesis.

4.
Curr Microbiol ; 81(8): 222, 2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38874817

RESUMEN

In the present scenario, growing population demands more food, resulting in the need for sustainable agriculture. Numerous approaches are explored in response to dangers and obstacles to sustainable agriculture. A viable approach is to be exploiting microbial consortium, which generate diverse biostimulants with growth-promoting characteristics for plants. These bioinoculants play an indispensable role in optimizing nutrient uptake efficiency mitigating environmental stress. Plant productivity is mostly determined by the microbial associations that exist at the rhizospheric region of plants. The engineered consortium with multifunctional attributes can be effectively employed to improve crop growth efficacy. A number of approaches have been employed to identify the efficient consortia for plant growth and enhanced crop productivity. Various plant growth-promoting (PGP) microbes with host growth-supporting characteristics were investigated to see if they might work cohesively and provide a cumulative effect for improved growth and crop yield. The effective microbial consortia should be assessed using compatibility tests, pot experimentation techniques, generation time, a novel and quick plant bioassay, and sensitivity to external stimuli (temperature, pH). The mixture of two or more microbial strains found in the root microbiome stimulates plant growth and development. The present review deals with mechanism, formulation, inoculation process, commercialization, and applications of microbial consortia as plant bioinoculants for agricultural sustainability.


Asunto(s)
Agricultura , Productos Agrícolas , Consorcios Microbianos , Desarrollo de la Planta , Agricultura/métodos , Productos Agrícolas/microbiología , Microbiología del Suelo , Raíces de Plantas/microbiología , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/genética , Rizosfera , Plantas/microbiología , Microbiota
5.
Curr Microbiol ; 81(8): 251, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38954017

RESUMEN

A new area of biotechnology is nanotechnology. Nanotechnology is an emerging field that aims to develope various substances with nano-dimensions that have utilization in the various sectors of pharmaceuticals, bio prospecting, human activities and biomedical applications. An essential stage in the development of nanotechnology is the creation of nanoparticles. To increase their biological uses, eco-friendly material synthesis processes are becoming increasingly important. Recent years have shown a lot of interest in nanostructured materials due to their beneficial and unique characteristics compared to their polycrystalline counterparts. The fascinating performance of nanomaterials in electronics, optics, and photonics has generated a lot of interest. An eco-friendly approach of creating nanoparticles has emerged in order to get around the drawbacks of conventional techniques. Today, a wide range of nanoparticles have been created by employing various microbes, and their potential in numerous cutting-edge technological fields have been investigated. These particles have well-defined chemical compositions, sizes, and morphologies. The green production of nanoparticles mostly uses plants and microbes. Hence, the use of microbial nanotechnology in agriculture and plant science is the main emphasis of this review. The present review highlights the methods of biological synthesis of nanoparticles available with a major focus on microbially synthesized nanoparticles, parameters and biochemistry involved. Further, it takes into account the genetic engineering and synthetic biology involved in microbial nanobiosynthesis to the construction of microbial nanofactories.


Asunto(s)
Nanopartículas , Nanotecnología , Nanotecnología/métodos , Nanopartículas/química , Bacterias/metabolismo , Bacterias/genética , Biotecnología/métodos , Biología Sintética/métodos , Nanoestructuras/química
6.
Semin Cancer Biol ; 86(Pt 2): 1179-1189, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-34302959

RESUMEN

Gynecologic cancers, starting in the reproductive organs of females, include cancer of cervix, endometrium, ovary commonly and vagina and vulva rarely. The changes in the composition of microbiome in gut and vagina affect immune and metabolic signaling of the host cells resulting in chronic inflammation, angiogenesis, cellular proliferation, genome instability, epithelial barrier breach and metabolic dysregulation that may lead to the onset or aggravated progression of gynecologic cancers. While microbiome in gynecologic cancers is just at horizon, certain significant microbiome signature associations have been found. Cervical cancer is accompanied with high loads of human papillomavirus, Fusobacteria and Sneathia species; endometrial cancer is reported to have presence of Atopobium vaginae and Porphyromonas species and significantly elevated levels of Proteobacteria and Firmicutes phylum bacteria, with Chlamydia trachomatis, Lactobacillus and Mycobacterium reported in ovarian cancer. Balancing microbiome composition in gynecologic cancers has the potential to be used as a therapeutic target. For example, the Lactobacillus species may play an important role in blocking adhesions of incursive pathogens to vaginal epithelium by lowering the pH, producing bacteriocins and employing competitive exclusions. The optimum or personalized balance of the microbiota can be maintained using pre- and probiotics, and fecal microbiota transplantations loaded with specific bacteria. Current evidence strongly suggest that a healthy microbiome can train and trigger the body's immune response to attack various gynecologic cancers. Furthermore, microbiome modulations can potentially contribute to improvements in immuno-oncology therapies.


Asunto(s)
Neoplasias de los Genitales Femeninos , Microbiota , Probióticos , Humanos , Femenino , Vagina/microbiología , Lactobacillus , Microbiota/genética , Neoplasias de los Genitales Femeninos/etiología , Neoplasias de los Genitales Femeninos/terapia , Probióticos/uso terapéutico
7.
BMC Plant Biol ; 23(1): 552, 2023 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-37940862

RESUMEN

In this study, we investigated the intricate interplay between Trichoderma and the tomato genome, focusing on the transcriptional and metabolic changes triggered during the late colonization event. Microarray probe set (GSE76332) was utilized to analyze the gene expression profiles changes of the un-inoculated control (tomato) and Trichoderma-tomato interactions for identification of the differentially expressed significant genes. Based on principal component analysis and R-based correlation, we observed a positive correlation between the two cross-comaparable groups, corroborating the existence of transcriptional responses in the host triggered by Trichoderma priming. The statistically significant genes based on different p-value cut-off scores [(padj-values or q-value); padj-value < 0.05], [(pcal-values); pcal-value < 0.05; pcal < 0.01; pcal < 0.001)] were cross compared. Through cross-comparison, we identified 156 common genes that were consistently significant across all probability thresholds, and showing a strong positive corelation between p-value and q-value in the selected probe sets. We reported TD2, CPT1, pectin synthase, EXT-3 (extensin-3), Lox C, and pyruvate kinase (PK), which exhibited upregulated expression, and Glb1 and nitrate reductase (nii), which demonstrated downregulated expression during Trichoderma-tomato interaction. In addition, microbial priming with Trichoderma resulted into differential expression of transcription factors related to systemic defense and flowering including MYB13, MYB78, ERF2, ERF3, ERF5, ERF-1B, NAC, MADS box, ZF3, ZAT10, A20/AN1, polyol sugar transporter like zinc finger proteins, and a novel plant defensin protein. The potential bottleneck and hub genes involved in this dynamic response were also identified. The protein-protein interaction (PPI) network analysis based on 25 topmost DEGS (pcal-value < 0.05) and the Weighted Correlation Gene Network Analysis (WGCNA) of the 1786 significant DEGs (pcal-value < 0.05) we reported the hits associated with carbohydrate metabolism, secondary metabolite biosynthesis, and the nitrogen metabolism. We conclude that the Trichoderma-induced microbial priming re-programmed the host genome for transcriptional response during the late colonization event and were characterized by metabolic shifting and biochemical changes specific to plant growth and development. The work also highlights the relevance of statistical parameters in understanding the gene regulatory dynamics and complex regulatory networks based on differential expression, co-expression, and protein interaction networks orchestrating the host responses to beneficial microbial interactions.


Asunto(s)
Hypocreales , Solanum lycopersicum , Transcriptoma , Solanum lycopersicum/genética , Perfilación de la Expresión Génica , Proteínas de Plantas/genética
8.
BMC Microbiol ; 23(1): 54, 2023 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-36864373

RESUMEN

BACKGROUND: Trichoderma asperellum and T. harzianum were assessed in this study as a potential biological control against Colletotrichum truncatum. C. truncatum is a hemibiotrophic fungus that causes anthracnose disease in chilli thereby affecting plant growth and fruit yield. Scanning electron microscope (SEM) technique showed the beneficial interaction between chilli root-Trichoderma spp. inducing the plant growth promotion, mechanical barrier, and defense network under C. truncatum challenged conditions. METHODS: Seeds bio-primed with T. asperellum, T. harzianum, and T. asperellum + T. harzianum promoted the plant growth parameters and strengthening of physical barrier via lignification on the wall of vascular tissues. Seed primed with bioagents were used for exploring the molecular mechanism of defense response in pepper against anthracnose to assess the temporal expression of six defense genes in the Surajmukhi variety of Capsicum annuum. QRT-PCR demonstrated induction of defense responsive genes in chilli pepper bioprimed with Trichoderma spp. such as plant defensin 1.2 (CaPDF1.2), superoxide dismutase (SOD), ascorbate peroxidase (APx), guaiacol peroxidase (GPx), pathogenesis related proteins PR-2 and PR-5. RESULTS: The results showed that bioprimed seeds were assessed for T. asperellum, T. harzianum, and T. asperellum + T. harzianum-chilli root colonization interaction under in vivo conditions. The results of the scanning electron microscope revealed that T. asperellum, T. harzianum and T. asperellum + T. harzianum interact with chilli roots directly via the development of plant-Trichoderma interaction system. Seeds bio-primed with bioagents promoted the plant growth parameters, fresh and dry weight of shoot and root, plant height, leaf area index, number of leaves, stem diameter and strengthening of physical barrier via lignification on the wall of vascular tissues and expression of six defense related genes in pepper against anthracnose. CONCLUSIONS: Application of T. asperellum and T. harzianum and in combination of treatments enhanced the plant growth. Further, as seeds bioprimed with T. asperellum, T. harzianum and in combination with treatment of T. asperellum + T. harzianum induced the strengthening of the cell wall by lignification and expression of six defense related genes CaPDF1.2, SOD, APx, GPx, PR-2 and PR-5 in pepper against C. truncatum. Our study contributed for better disease management through biopriming with T. asperellum, T. harzianum and T. asperellum + T. harzianum. The biopriming possess enormous potential to promote plant growth, modulate the physical barrier, and induced the defense related genes in chilli pepper against anthracnose.


Asunto(s)
Capsicum , Colletotrichum , Hypocreales , Colletotrichum/genética , Alcanfor
9.
Phys Rev Lett ; 130(22): 220201, 2023 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-37327437

RESUMEN

Nonlocality, as established by the seminal Bell's theorem, is considered to be the most striking feature of correlations present in spacelike separated events. Its practical application in device independent protocols, such as secure key distribution, randomness certification, etc., demands identification and amplification of such correlations observed in the quantum world. In this Letter we study the prospect of nonlocality distillation, wherein, by applying a natural set of free operations (called wirings) on many copies of weakly nonlocal systems, one aims to generate correlations of higher nonlocal strength. In the simplest Bell scenario, we identify a protocol, namely, logical OR-AND wiring, that can distill nonlocality to a significantly high degree starting from arbitrarily weak quantum nonlocal correlations. As it turns out, our protocol has several interesting facets: (i) it demonstrates that a set of distillable quantum correlations has nonzero measure in the full eight-dimensional correlation space, (ii) it can distill quantum Hardy correlations by preserving its structure, (iii) it shows that (nonlocal) quantum correlations sufficiently close to the local deterministic points can be distilled by a significant amount. Finally, we also demonstrate efficacy of the considered distillation protocol in detecting postquantum correlations.

10.
Int J Mol Sci ; 24(2)2023 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-36674611

RESUMEN

Plants experience different stresses, i.e., abiotic, or biotic, and to combat them, plants re-program the expression of growth-, metabolism-, and resistance-related genes. These genes differ in their synonymous codon usage frequency and show codon usage bias. Here, we investigated the correlation among codon usage bias, gene expression, and underlying mechanisms in rice under abiotic and biotic stress conditions. The results indicated that genes with higher expression (up- or downregulated) levels had high GC content (≥60%), a low effective number of codon usage (≤40), and exhibited strong biases towards the codons with C/G at the third nucleotide position, irrespective of stress received. TTC, ATC, and CTC were the most preferred codons, while TAC, CAC, AAC, GAC, and TGC were moderately preferred under any stress (abiotic or biotic) condition. Additionally, downregulated genes are under mutational pressure (R2 ≥ 0.5) while upregulated genes are under natural selection pressure (R2 ≤ 0.5). Based on these results, we also identified the possible target codons that can be used to design an optimized set of genes with specific codons to develop climate-resilient varieties. Conclusively, under stress, rice has a bias towards codon usage which is correlated with GC content, gene expression level, and gene length.


Asunto(s)
Uso de Codones , Oryza , Oryza/genética , Codón/genética , Mutación , Aclimatación
11.
Genes Immun ; 23(1): 47-50, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34635809

RESUMEN

The rapid expansion of coronavirus SARS-CoV-2 has impacted various ethnic groups all over the world. The burden of infectious diseases including COVID-19 are generally reported to be higher for the Indigenous people. The historical knowledge have also suggested that the indigenous populations suffer more than the general populations in the pandemic. Recently, it has been reported that the indigenous groups of Brazil have been massively affected by COVID-19. Series of studies have shown that many of the indigenous communities reached at the verge of extinction due to this pandemic. Importantly, South Asia also has several indigenous and smaller communities, that are living in isolation. Till date, despite the two consecutive waves in India, there is no report on the impact of COVID-19 for indigenous tribes. Since smaller populations experiencing drift may have greater risk of such pandemic, we have analysed Runs of Homozygosity (ROH) among South Asian populations and identified several populations with longer homozygous segments. The longer runs of homozygosity at certain genomic regions may increases the susceptibility for COVID-19. Thus, we suggest extreme careful management of this pandemic among isolated populations of South Asia.


Asunto(s)
COVID-19 , Humanos , India , Lingüística , Pandemias , SARS-CoV-2
12.
Physiol Mol Biol Plants ; 27(3): 535-541, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33854282

RESUMEN

In salt-prone areas, plant growth and productivity is adversely affected. In the present study, the ZT1-ZT6 transgenic tomato lines having BcZAT12 gene under the regulatory control of the stress inducible Bclea1 promoter were exposed to three salinity levels (50, 100 and 200 mM) at the four leaf stage for 10 days. The transgenic lines showed improved growth in stem height, leaf area, root length and shoot length under saline conditions, as compared to control. Moreover, ZT1 and ZT5 lines showed lower electrolyte leakage and decreased hydrogen peroxide formation, in combination with elevated relative water content, proline and chlorophyll levels. The enzyme activity of catalase was also enhanced in ZT1 and ZT5. These results poses the present lines as an attractive alternative for tomato cultivation in salinity-affected areas.

13.
Phys Rev Lett ; 125(15): 150502, 2020 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-33095608

RESUMEN

In a network, a channel introduces correlations to the parties that aim to establish a communication protocol. We present a framework of nonlocal network coding by exploiting a Bell scenario and show the usefulness of nonlocal and quantum resources in network coding. Two-sender and two-receiver interference channels are considered, for which network coding is characterized by two-input and four-outcome Bell scenarios. It is shown that nonsignaling correlations lead to strictly higher channel capacities than quantum correlations in general. This also holds true for quantum and local correlations: network coding with quantum resources shows a strictly higher channel capacity than local ones. It turns out, however, that more nonlocality does not necessarily imply a higher channel capacity. The framework can be generally applied to network communication protocols.

14.
Neuroendocrinology ; 110(5): 422-429, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31269501

RESUMEN

Germinomas are highly immunogenic tumors eliciting a strong peri-tumoral immune response that can spillover into the surrounding healthy tissues. This phenomenon can also occur in intracranial germinomas, manifesting as secondary hypophysitis. Herein, we report a case of 12-year-old-girl presenting with polyuria and polydispsia. She had central diabetes insipidus (CDI) and panhypopituitarism. Imaging revealed a sellar-suprasellar mass with infundibular stalk thickening. Transphenoidal biopsy revealed epithelioid granulomas with immunostaining negative for germinomatous cells. Other causes of hypophysitis were ruled out. Accordingly, she was diagnosed as primary granulomatous hypophysitis and treated with high-dose corticosteroids. Three years later she again presented with headache, vomiting and diminution of vision. Imaging showed a heterogeneous, solid-cystic peripheral rim-enhancing lesion at the same location with involvement of hypothalamus, ependyma and pineal gland. Cerebrospinal fluid beta-human chorionic gonadotropin was markedly elevated, confirming the diagnosis of an intracranial germ cell tumor. She was started on chemotherapy; however, she succumbed to febrile neutropenia. We performed a literature search and found 18 anecdotal cases of secondary hypophysitis associated with intracranial germinomas. There was a slight male preponderance (male:female 5:4). Two-thirds of the cases were below 18 years of age. Polyuria was the most common presenting manifestation (83%). CDI and panhypopituitarism were seen in 89 and 78% cases, respectively. Imaging evidence of pituitary stalk thickening was seen in 12 cases (67%), while pituitary enlargement and/or sellar mass were reported in 11 cases (61%). Pineal involvement was extremely rare, being reported in only 1 case, implying the predilection of suprasellar (rather than pineal) germinomas in causing secondary hypophysitis. Histologically, 82% had lymphocytic hypophysitis, while 18% had granulomatous hypophysitis. Initially, the diagnosis of germinoma was missed in 60% of the cases who were wrongly treated with corticosteroids. To conclude, physicians should make it a dictum that all children and adolescents presenting with CDI and pituitary stalk thickening should be rigorously screened for an underlying intracranial germinoma before labeling them as primary hypophysitis.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Germinoma/diagnóstico , Granuloma/diagnóstico , Hipofisitis/diagnóstico , Hipopituitarismo/diagnóstico , Adolescente , Niño , Femenino , Humanos , Masculino
16.
Appl Environ Microbiol ; 84(23)2018 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-30217849

RESUMEN

The genome of Azospirillum brasilense encodes five RpoH sigma factors: two OxyR transcription regulators and three catalases. The aim of this study was to understand the role they play during oxidative stress and their regulatory interconnection. Out of the 5 paralogs of RpoH present in A. brasilense, inactivation of only rpoH1 renders A. brasilense heat sensitive. While transcript levels of rpoH1 were elevated by heat stress, those of rpoH3 and rpoH5 were upregulated by H2O2 Catalase activity was upregulated in A. brasilense and its rpoH::km mutants in response to H2O2 except in the case of the rpoH5::km mutant, suggesting a role for RpoH5 in regulating inducible catalase. Transcriptional analysis of the katN, katAI, and katAII genes revealed that the expression of katN and katAII was severely compromised in the rpoH3::km and rpoH5::km mutants, respectively. Regulation of katN and katAII by RpoH3 and RpoH5, respectively, was further confirmed in an Escherichia coli two-plasmid system. Regulation of katAII by OxyR2 was evident by a drastic reduction in growth, KatAII activity, and katAII::lacZ expression in an oxyR2::km mutant. This study reports the involvement of RpoH3 and RpoH5 sigma factors in regulating oxidative stress response in alphaproteobacteria. We also report the regulation of an inducible catalase by a cascade of alternative sigma factors and an OxyR. Out of the three catalases in A. brasilense, those corresponding to katN and katAII are regulated by RpoH3 and RpoH5, respectively. The expression of katAII is regulated by a cascade of RpoE1→RpoH5 and OxyR2.IMPORTANCEIn silico analysis of the A. brasilense genome showed the presence of multiple paralogs of genes involved in oxidative stress response, which included 2 OxyR transcription regulators and 3 catalases. So far, Deinococcus radiodurans and Vibrio cholerae are known to harbor two paralogs of OxyR, and Sinorhizobium meliloti harbors three catalases. We do not yet know how the expression of multiple catalases is regulated in any bacterium. Here we show the role of multiple RpoH sigma factors and OxyR in regulating the expression of multiple catalases in A. brasilense Sp7. Our work gives a glimpse of systems biology of A. brasilense used for responding to oxidative stress.


Asunto(s)
Azospirillum brasilense/enzimología , Catalasa/genética , Regulación Bacteriana de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Proteínas de Choque Térmico/metabolismo , Proteínas Represoras/metabolismo , Factor sigma/metabolismo , Factores de Transcripción/metabolismo , Azospirillum brasilense/genética , Azospirillum brasilense/metabolismo , Catalasa/metabolismo , Proteínas de Choque Térmico/genética , Peróxido de Hidrógeno/metabolismo , Estrés Oxidativo , Regiones Promotoras Genéticas , Proteínas Represoras/genética , Factor sigma/genética , Factores de Transcripción/genética
17.
Neurol India ; 66(5): 1351-1358, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30233002

RESUMEN

PURPOSE: Endocrinal insufficiency caused by vasculotoxic snake envenomation is under-recognized and is mostly confined to a specific geographic area. We conducted a prospective study to determine the prevalence and pattern of pituitary-target gland insufficiencies caused by snake envenomation. MATERIALS AND METHODS: The hormonal evaluation of patients who had suffered from vasculotoxic snake envenomation was done at baseline and at 6 months of follow-up. Those patients with a documented hormonal insufficiency underwent magnetic resonance imaging (MRI) of the hypothalamo-pituitary area. The severity of envenomation was assessed by the acute physiology and chronic health evaluation II (APACHE-II) score, the sepsis-related organ failure assessment (SOFA) score, and the snake bite severity score (SBSS) for all patients. RESULTS: Seventy-six patients were seen during the study period, of which 60 were available for a repeat hormonal evaluation at 6 months, with the majority of patients belonging to the middle age group (mean age, 37.6 ± 14.9 years). The mean lag period at presentation was 32 ± 20 h. Thirty-five patients (46.1%) had coagulopathy, 20 patients (26.3%) had acute kidney injury (AKI), and 8 of 76 patients (10.5%) needed renal replacement therapy (RRT) in the form of hemodialysis. Six patients (out of 41 with vasculotoxic bites) developed chronic hypopituitarism, which was in continuation with the acute hypopituitarism that they developed. Growth hormone and glucocorticoid deficiencies were the most common endocrinopathies observed. The occurrence of hypopituitarism was observed only in patients with a vasculotoxic snake bite (due to Russell's viper); coagulopathy, renal insufficiency, or any of the scoring tools did not predict the occurrence of hypopituitarism. CONCLUSION: Acute asymptomatic and chronic symptomatic or asymptomatic hypopituitarism are important sequelae of viper bite in a small proportion of patients and can occur in the presence of normal pituitary imaging. Routine prospective pituitary hormone screening should be done in all patients within the first 6 months of envenomation by the vasculotoxic snakebite as chronic pituitary dysfunction can often occur in these patients.


Asunto(s)
Hipopituitarismo/etiología , Hipófisis/fisiopatología , Mordeduras de Serpientes/complicaciones , Adulto , Animales , Femenino , Humanos , Hipopituitarismo/diagnóstico por imagen , Hipopituitarismo/fisiopatología , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Hipófisis/diagnóstico por imagen , Estudios Prospectivos , Daboia , Mordeduras de Serpientes/diagnóstico por imagen , Mordeduras de Serpientes/fisiopatología , Sobrevivientes , Adulto Joven
18.
Plant Cell Physiol ; 58(2): 287-297, 2017 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-27837096

RESUMEN

Alternative sigma factors belonging to Group 3 are thought to play an important role in the adaptation of cyanobacteria to environmental challenges by altering expression of genes needed for coping with such stresses. In this study, the role of an alternative sigma factor, SigJ, was analyzed in the filamentous nitrogen-fixing cyanobacterium, Anabaena sp. PCC 7120 by knocking down the expression of the sigJ gene (alr0277) employing an antisense RNA-mediated approach. In the absence of any stress, the knock-down (KD0277) or the wild-type strain both grew similarly. Upon exposure to high-intensity light, KD0277 showed substantially reduced bleaching of its pigments, higher photosynthetic activity and consequently better survival than the wild type. KD0277 also showed an enhanced accumulation of two carotenoids, which were identified as myxoxanthophyll and keto-myxoxanthophyll. Further, KD0277 was more tolerant to ammonium-triggered photodamage than the wild type. Moreover, PSII was better protected against photodamage in KD0277 than in the wild type. Down-regulation of sigJ in Anabaena PCC 7120, however, reduced its ability to cope with desiccation. This study demonstrates that down-regulation of the sigJ gene in Anabaena PCC 7120 differentially affects its ability to tolerate two environmentally relevant stresses, i.e. high-intensity light and desiccation.


Asunto(s)
Anabaena/metabolismo , Proteínas Bacterianas/metabolismo , Factor sigma/metabolismo , Anabaena/genética , Anabaena/efectos de la radiación , Proteínas Bacterianas/genética , Desecación , Regulación Bacteriana de la Expresión Génica/genética , Regulación Bacteriana de la Expresión Génica/fisiología , Regulación Bacteriana de la Expresión Génica/efectos de la radiación , Luz , Factor sigma/genética
19.
Neurol India ; 65(6): 1312-1316, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29133707

RESUMEN

BACKGROUND: Patients with acromegaly have 2-3 times the expected mortality rates primarily due to cardiovascular risks. Echocardiographic studies showing improvement of cardiac function following transsphenoidal surgery (TSS) are limited. MATERIALS AND METHODS: All patients with acromegaly underwent preoperative echocardiography and tissue Doppler (Philips i33, 3D ECHO) for assessment of cardiac indices. In the prospective group of patients, echocardiography was repeated after 6 months of surgery. In the retrospective group of patients, echocardiography was performed for left ventricular diastolic dysfunction and ejection fraction. Biochemical cure was confirmed at least after 6 months by glucose-suppressed plasma growth hormone (GH) concentrations (GH-OGTT) of less than 0.4 ng/ml, random GH of less than 1 ng/ml, and normal age-corrected insulin-like growth factor (IGF-1) values. RESULTS: In the prospective group (38 patients), there was a significant decrease in the left ventricular mass (LVM) and LVM index (LVMI) in patients who were cured as well as in patients with postoperative growth hormone (GH) 1-5 ng/ml. In the prospective group, LVMI completely normalized in 2 and a new-onset deterioration was detected in 1 patient (who was not cured) and improved in 8 others. Left ventricular systolic function was abnormal at baseline in 18 (47.3%) patients, which normalized in 11 (61.1%) patients postoperatively, and in 7 patients, it improved significantly although it did not normalize completely. There was also a significant improvement in the left ventricular ejection fraction (P = 0.01). Post TSS, in patients with GH-OGTT >5 ng/ml, there was no significant decrease in the LVM, LVMI and ejection fraction (EF). In the retrospective group, 62 patients were analyzed for a change in the EF with a mean follow-up of 20.3 months. There was a significant improvement in the left ventricular EF in patients who were cured (P < 0.001). CONCLUSION: Reduction in growth hormone levels and insulin-like growth factor type 1 can decrease the LVM and LVMI, which directly or indirectly contributes to the improvement in diastolic as well as systolic function and probably mortality.


Asunto(s)
Acromegalia/cirugía , Cardiomiopatías/cirugía , Factor I del Crecimiento Similar a la Insulina/metabolismo , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estudios Retrospectivos , Resultado del Tratamiento
20.
J Bacteriol ; 198(21): 2955-2964, 2016 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-27551017

RESUMEN

Carotenoids constitute an important component of the defense system against photooxidative stress in bacteria. In Azospirillum brasilense Sp7, a nonphotosynthetic rhizobacterium, carotenoid synthesis is controlled by a pair of extracytoplasmic function sigma factors (RpoEs) and their cognate zinc-binding anti-sigma factors (ChrRs). Its genome harbors two copies of the gene encoding geranylgeranyl pyrophosphate synthase (CrtE), the first critical step in the carotenoid biosynthetic pathway in bacteria. Inactivation of each of two crtE paralogs found in A. brasilense caused reduction in carotenoid content, suggesting their involvement in carotenoid synthesis. However, the effect of crtE1 deletion was more pronounced than that of crtE2 deletion. Out of the five paralogs of rpoH in A. brasilense, overexpression of rpoH1 and rpoH2 enhanced carotenoid synthesis. Promoters of crtE2 and rpoH2 were found to be dependent on RpoH2 and RpoE1, respectively. Using a two-plasmid system in Escherichia coli, we have shown that the crtE2 gene of A. brasilense Sp7 is regulated by two cascades of sigma factors: one consisting of RpoE1and RpoH2 and the other consisting of RpoE2 and RpoH1. In addition, expression of crtE1 was upregulated indirectly by RpoE1 and RpoE2. This study shows, for the first time in any carotenoid-producing bacterium, that the regulation of carotenoid biosynthetic pathway involves a network of multiple cascades of alternative sigma factors. IMPORTANCE: Carotenoids play a very important role in coping with photooxidative stress in prokaryotes and eukaryotes. Although extracytoplasmic function (ECF) sigma factors are known to directly regulate the expression of carotenoid biosynthetic genes in bacteria, regulation of carotenoid biosynthesis by one or multiple cascades of sigma factors had not been reported. This study provides the first evidence of the involvement of multiple cascades of sigma factors in the regulation of carotenoid synthesis in any bacterium by showing the regulation of a gene encoding geranylgeranyl pyrophosphate synthase (crtE2) by RpoE1→RpoH2→CrtE2 and RpoE2→RpoH1→CrtE2 cascades in A. brasilense It also provides an insight into existence of an additional cascade or cascades regulating expression of another paralog of crtE.


Asunto(s)
Azospirillum brasilense/metabolismo , Proteínas Bacterianas/metabolismo , Carotenoides/biosíntesis , Factor sigma/metabolismo , Azospirillum brasilense/genética , Proteínas Bacterianas/genética , Vías Biosintéticas , Regulación Bacteriana de la Expresión Génica , Regiones Promotoras Genéticas , Factor sigma/genética , Transcripción Genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA