RESUMO
How the HIF-1 (Hypoxia-Inducible) transcription factor drives and coordinates distinct responses to low oxygen across diverse cell types is poorly understood. We present a multi-tissue single-cell gene-expression atlas of the hypoxia response of the nematode Caenorhabditis elegans . This atlas highlights how cell-type-specific HIF-1 responses overlap and diverge among and within neuronal, intestinal, and muscle tissues. Using the atlas to guide functional analyses of candidate muscle-specific HIF-1 effectors, we discovered that HIF-1 activation drives downregulation of the tspo-1 ( TSPO, Translocator Protein) gene in vulval muscle cells to modulate a hypoxia-driven change in locomotion caused by contraction of body-wall muscle cells. We further showed that in human cardiomyocytes HIF-1 activation decreases levels of TSPO and thereby alters intracellular cholesterol transport and the mitochondrial network. We suggest that TSPO-1 is an evolutionarily conserved mediator of HIF-1-dependent modulation of muscle and conclude that our gene-expression atlas can help reveal how HIF-1 drives cell-specific adaptations to hypoxia.
RESUMO
Pigeon pea (Cajanus cajan) is widely cultivated for its nutritional and medicinal value yet remains an orphan crop as productivity has not been improved because of a lack of genome and non-coding genome information. Non-coding RNAs, like miRNAs and long non-coding RNAs (lncRNAs), are involved in regulation of growth, metabolism, development, and stress response, and have a critical role in post-transcriptional gene regulation (PTGR). We attempted to elucidate the roles of miRNAs and lncRNAs in pigeon pea through experimental validation of computationally predicted miRNAs and lncRNAs and targets of miRNAs on mRNAs. We experimentally validated 20 miRNAs and 11 lncRNAs. We predicted cleavage sites of three miRNA targets: serine/threonine-protein kinase, polygalacturonase, beta-galactosidase. We identified 469 targets of 265 miRNAs and their functional annotations using computational methods. We built a miRNA-mRNA-lncRNA network model, with the miRNAs targeting both mRNAs and lncRNAs, to obtain information on the interplay of these three molecules. A confirmed interaction through experimental validation was established between miRNA, namely cca-miR1535a targeting the mRNA for beta-galactosidase, as well as the lncRNA cca-lnc-020033. Our findings increase knowledge of the non-coding genome of pigeon pea and their roles in PTGR and in improving agronomic traits of this pulse crop.
Assuntos
Cajanus , Regulação da Expressão Gênica de Plantas , MicroRNAs , RNA Longo não Codificante , RNA Mensageiro , RNA de Plantas , Cajanus/genética , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/genéticaRESUMO
Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (â¼0.063% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.
Assuntos
Planeta Terra , Ecossistema , Regiões Antárticas , RNA Ribossômico 16S , Sistema SolarAssuntos
COVID-19 , Humanos , COVID-19/epidemiologia , Pandemias , Atenção à Saúde , SARS-CoV-2 , Índia/epidemiologiaRESUMO
Uterine leiomyomas, or fibroids, are common, benign tumors for which hysterectomy is the only definitive treatment. The extracellular matrix of fibroids is disorganized and stiffer than the surrounding myometrial tissue. To understand how stiffness affects fibroid cells, patient-matched fibroid and myometrial cells were cultured on substrates with stiffnesses varying from 0.2 to 150 kPa. Fibroid cells grew more slowly than myometrial cells overall, and only the myometrial cells altered their growth rate in response to stiffness. In both cell types, cell proliferation decreased with inhibition of PI3K and increased with inhibition of IGF-1. The cellular area was greater for the fibroid cells. The only significant effect of stiffness on the cell area was between the 0.2 and 64 kPa substrates, and this was true for both cell types. To investigate intracellular stiffness, intracellular particle tracking microrheology was used. Fibroid cells exhibited a more than 100-fold increase in elastic modulus at a frequency of 1 Hz in response to the addition of external stress, while myometrial cells showed little change in elastic modulus. Overall, the responses of both cells followed similar trends in response to stiffness and inhibitors, although the response was attenuated in the fibroid cells. The changes that were demonstrated by the change in intracellular stiffness with response to compression suggest that other mechanical forces may provide insight into differences in the two cell types.
Assuntos
Leiomioma , Neoplasias Uterinas , Feminino , Humanos , Neoplasias Uterinas/metabolismo , Sinais (Psicologia) , Leiomioma/metabolismo , Miométrio/metabolismo , HisterectomiaRESUMO
BACKGROUND: Surgical site infection (SSI) is the most common complication of abdominal surgery, with substantial costs to patients and health systems. Heterogeneity in costing methods in existing SSI studies makes multi-country comparison challenging. The objective of the study was to assess the costs of SSI across middle-income countries. METHODS: Centres from a randomized controlled trial assessing interventions to reduce SSI (FALCON, ClinicalTrials.gov, NCT03700749NCT) were sampled from two upper-middle- (India, Mexico) and two lower-middle- (Ghana, Nigeria) income countries. The Key resource use In Wound Infection (KIWI) study collected data on postoperative resource use and costs from consecutive patients undergoing abdominal surgery with an incision >5 cm (including caesarean section) that were recruited to FALCON between April and October 2020. The overall costs faced by patients with and without SSI were compared by operative field contamination (clean-contaminated vs contaminated-dirty), country and timing (inpatient vs outpatient). FINDINGS: A total of 335 patients were included in KIWI; SSI occurred in 7% of clean-contaminated cases and 27% of contaminated-dirty cases. Overall, SSI was associated with an increase in postoperative healthcare costs by 75.3% (412 international Euros) after clean-contaminated surgery and 66.6% (331) after contaminated-dirty surgery. The highest and lowest cost increases were in India for clean-contaminated cases (517) and contaminated-dirty cases (223), respectively. Overall, inpatient costs accounted for 96.4% of the total healthcare costs after clean-contaminated surgery and 92.5% after contaminated-dirty surgery. CONCLUSION: SSI was associated with substantial additional postoperative costs across a range of settings. Investment in health technologies to reduce SSI may mitigate the financial burden to patients and low-resource health systems.
Assuntos
Países em Desenvolvimento , Infecção da Ferida Cirúrgica , Feminino , Humanos , Gravidez , Cesárea/efeitos adversos , Coleta de Dados , Fatores de Risco , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/prevenção & controle , Infecção da Ferida Cirúrgica/etiologiaRESUMO
Data on stool form and defecation frequency which are a prerequisite for defining normal bowel habit are lacking in Bangladesh. This observational cross sectional study was designed to find out defecation frequency and stool form among general population in Bangladesh. This study was performed in the Department of Gastroenterology, Shaheed Suhrawardy Medical College Hospital, Dhaka, Bangladesh from July 2017 to June 2018. Apparently healthy 1090 respondents were evaluated for predominant stool form (Bristol chart) and frequency. Data on demographic and life-style were collected. The study population consisted of 1090 respondents, among them, 65.13% male and 34.87% female and mean age of them was 40.20±12.39 years. Most of the people 874(80.2%) passed stool between 12-14 times per week followed by 111(10.2%) less than 3 stools per week, 95(8.7%) passed more than 14 stools per week and 10(0.9%) between 3-12 stools per week, p<0.001. Most people passed predominantly Bristol type IV stool- 610(56.0%); followed by type III- 274(25.1%). Other stool forms were: type I- 52(4.8%), type II- 59(5.4%), type V- 31(2.8%), type VI- 33(3.0%), type VII- 31(2.8%), p<0.001. In regard to the physical activity, most of the respondents (70.0%) are physically active whereas about 13.0% are sedentary and about 17.0% are physically intermediate between the two, p<0.001. In the case of dietary habit, most of the participants are non-vegetarian (82.5%) and the remaining are vegetarian (11.1%) and occasional non vegetarian (6.4%), p<0.001. Median stool frequency in the studied population was 14 per week and predominant form was Bristol type IV. Older age was associated with lesser stool frequency, particularly among female subjects.
Assuntos
Defecação , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Bangladesh , Fezes , Estudos TransversaisRESUMO
This paper attempts to describe the outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (COVID-19) via an epidemic model. This virus has dissimilar effects in different countries. The number of new active coronavirus cases is increasing gradually across the globe. India is now in the second stage of COVID-19 spreading, it will be an epidemic very quickly if proper protection is not undertaken based on the database of the transmission of the disease. This paper is using the current data of COVID-19 for the mathematical modeling and its dynamical analysis. We bring in a new representation to appraise and manage the outbreak of infectious disease COVID-19 through SEQIR pandemic model, which is based on the supposition that the infected but undetected by testing individuals are send to quarantine during the incubation period. During the incubation period if any individual be infected by COVID-19, then that confirmed infected individuals are isolated and the necessary treatments are arranged so that they cannot taint the other residents in the community. Dynamics of the SEQIR model is presented by basic reproduction number R 0 and the comprehensive stability analysis. Numerical results are depicted through apt graphical appearances using the data of five states and India.
RESUMO
The animal model deals with the species other than the human, as it can imitate the disease progression, its' diagnosis as well as a treatment similar to human. Discovery of a drug and/or component, equipment, their toxicological studies, dose, side effects are in vivo studied for future use in humans considering its' ethical issues. Here lies the importance of the animal model for its enormous use in biomedical research. Animal models have many facets that mimic various disease conditions in humans like systemic autoimmune diseases, rheumatoid arthritis, epilepsy, Alzheimer's disease, cardiovascular diseases, Atherosclerosis, diabetes, etc., and many more. Besides, the model has tremendous importance in drug development, development of medical devices, tissue engineering, wound healing, and bone and cartilage regeneration studies, as a model in vascular surgeries as well as the model for vertebral disc regeneration surgery. Though, all the models have some advantages as well as challenges, but, present review has emphasized the importance of various small and large animal models in pharmaceutical drug development, transgenic animal models, models for medical device developments, studies for various human diseases, bone and cartilage regeneration model, diabetic and burn wound model as well as surgical models like vascular surgeries and surgeries for intervertebral disc degeneration considering all the ethical issues of that specific animal model. Despite, the process of using the animal model has facilitated researchers to carry out the researches that would have been impossible to accomplish in human considering the ethical prohibitions.
RESUMO
This paper is devoted to answering some questions using a mathematical model by analyzing India's first and second phases of the COVID-19 pandemic. A new mathematical model is introduced with a nonmonotonic incidence rate to incorporate the psychological effect of COVID-19 in society. The paper also discusses the local stability and global stability of an endemic equilibrium and a disease-free equilibrium. The basic reproduction number is evaluated using the proposed COVID-19 model for disease spread in India based on the actual data sets. The study of nonperiodic solutions at a positive equilibrium point is also analyzed. The model is rigorously studied using MATLAB to alert the decision-making bodies to hinder the emergence of any other pandemic outbreaks or the arrival of subsequent pandemic waves. This paper shows the excellent prediction of the first wave and very commanding for the second wave. The exciting results of the paper are as follows: (i) psychological effect on the human population has an impact on propagation; (ii) lockdown is a suitable technique mathematically to control the COVID spread; (iii) different variants produce different waves; (iv) the peak value always crosses its past value.
Assuntos
COVID-19 , COVID-19/epidemiologia , COVID-19/prevenção & controle , Controle de Doenças Transmissíveis/métodos , Humanos , Pandemias/prevenção & controle , SARS-CoV-2 , VacinaçãoRESUMO
The forecasting of the nature and dynamics of emerging coronavirus (COVID-19) pandemic has gained a great concern for health care organizations and governments. The efforts aim to to suppress the rapid and global spread of its tentacles and also control the infection with the limited available resources. The aim of this work is to employ real data set to propose and analyze a compartmental discrete time COVID-19 pandemic model with non-linear incidence and hence predict and control its outbreak through dynamical research. The Basic Reproduction Number ( R 0 ) is calculated analytically to study the disease-free steady state ( R 0 < 1 ), and also the permanency case ( R 0 > 1 ) of the disease. Numerical results show that the transmission rates α > 0 and ß > 0 are quite effective in reducing the COVID-19 infections in India or any country. The fitting and predictive capability of the proposed discrete-time system are presented for relishing the effect of disease through stability analysis using real data sets.
RESUMO
Hydrocephalus (HCP) is occurred when there is inequality in the formation and absorption of CSF to such a level which causes accumulation of fluid and causing raised intracranial pressure. Hydrocephalus is the most frequent neurosurgical problem encountered in the paediatric age group. CSF diversion surgically is needed as treatment for certain condition. Endoscopic third ventriculostomy (ETV) and Ventriculo-peritoneal shunt (VPS) are most widely used CSF diversion procedure. Therefore, this study was conducted for comparing the surgical outcome of ETV and VP shunt in obstructive hydrocephalus. This is a prospective experimental study conducted in the Department of Neurosurgery, Dhaka Medical College and Hospital (DMCH) and Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from January 2017 to December 2019. Paediatric patients of both sex and 6 months to 18 years of age with obstructive hydrocephalus undergone endoscopic third ventriculostomy (ETV) or ventriculo-peritoneal shunt (VP shunt) were included after fulfilling inclusion and exclusion criteria. The patients divided into two groups (Group A and Group B). The Group A included 30 patients who treated by Endoscopic third ventriculostomy and the Group B include 30 patients, who was treated by Ventriculo-peritoneal shunt. Surgical outcome was analyzed in two procedures separately. In Group A (ETV group) symptomatic improvement, GCS score improves earlier and post-operative complications relatively less than Group B (VP shunt group). But in VP shunt group 3 months follow up reveals- improvement of papilledema, Occipital frontal circumference (OFC) regression and fontanelle size improvement was more than that of ETV group. This study concluded with suggesting that Endoscopic third ventriculostomy (ETV) is technologically superior surgical technique than VP shunt. Though ETV showed relatively more immediate procedural failure and intraventricular hemorrhage but long-term outcome is better and also associated with lower incidence of infection and re-operation in comparison to VP shunt.
Assuntos
Hidrocefalia , Terceiro Ventrículo , Bangladesh , Criança , Drenagem , Humanos , Hidrocefalia/cirurgia , Estudos Prospectivos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Color detection is used by animals of diverse phyla to navigate colorful natural environments and is thought to require evolutionarily conserved opsin photoreceptor genes. We report that Caenorhabditis elegans roundworms can discriminate between colors despite the fact that they lack eyes and opsins. Specifically, we found that white light guides C. elegans foraging decisions away from a blue-pigment toxin secreted by harmful bacteria. These foraging decisions are guided by specific blue-to-amber ratios of light. The color specificity of color-dependent foraging varies notably among wild C. elegans strains, which indicates that color discrimination is ecologically important. We identified two evolutionarily conserved cellular stress response genes required for opsin-independent, color-dependent foraging by C. elegans, and we speculate that cellular stress response pathways can mediate spectral discrimination by photosensitive cells and organisms-even by those lacking opsins.
Assuntos
Caenorhabditis elegans/fisiologia , Caenorhabditis elegans/efeitos da radiação , Visão de Cores , Comportamento Alimentar , Animais , Aprendizagem da Esquiva , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/fisiologia , Sequência Conservada , Escherichia coli , Luz , Proteínas de Membrana/genética , Proteínas de Membrana/fisiologia , Proteínas Quinases/genética , Proteínas Quinases/fisiologia , Pseudomonas aeruginosa/metabolismo , Piocianina/metabolismo , Piocianina/toxicidadeRESUMO
Onchocerciasis is a neglected tropical disease (NTD) caused by Onchocerca Diesing 1841 (Spirurida: Onchocercidae) nematodes transmitted by blackflies. It is associated with poverty and imposes a significant health, welfare and economic burden on many tropical countries. Current methods to visualize infections within the vectors rely on invasive methods. However, using micro-computed tomography techniques, without interference from physical tissue manipulation, we visualized in three dimensions for the first time an L1 larva of an Onchocerca species within the thoracic musculature of a blackfly, Simulium damnosum s.l. Theobald 1903 (Diptera: Simuliidae), naturally infected in Ghana. The possibility that thicker peritrophic membranes in savannah flies could account for their lower parasite loads was not supported, but there were limits to our analysis. While there were no statistically significant differences between the mean thicknesses of the peritrophic membranes, in the anterior, dorsal and ventral regions, of forest and savannah blackflies killed 34-48 min after a blood-meal, the thickness of the peritrophic membrane in the posterior region could not be measured. Micro-computed tomography has the potential to provide novel information on many other parasite/vector systems and impactful images for public engagement in health education.
Assuntos
Oncocercose , Simuliidae , Animais , Florestas , Insetos Vetores , Onchocerca , Oncocercose/veterinária , Microtomografia por Raio-XRESUMO
OBJECTIVE: To assess the effect of tranexamic acid on intra-operative bleeding and surgical field visualisation. METHODS: Fifty patients undergoing various endoscopic ear surgical procedures, including endoscopic tympanoplasty, endoscopic atticotomy or mastoidectomy, endoscopic ossiculoplasty, and endoscopic stapedotomy, were randomly assigned to: a study group that received tranexamic acid or a control group which received normal saline. The intra-operative bleeding and operative field visualisation was graded using the Das and Mitra endoscopic ear surgery bleeding and field visibility score, which was separately analysed for the external auditory canal and the middle ear. RESULTS: The Das and Mitra score was better (p < 0.05) in the group that received tranexamic acid as a haemostat when working in the external auditory canal; with respect to the middle ear, no statistically significant difference was found between the two agents. Mean values for mean arterial pressure, heart rate and surgical time were comparable in both groups, with no statistically significant differences. CONCLUSION: Tranexamic acid appears to be an effective haemostat in endoscopic ear surgery, thus improving surgical field visualisation, especially during manipulation of the external auditory canal soft tissues.
Assuntos
Antifibrinolíticos/uso terapêutico , Meato Acústico Externo/cirurgia , Endoscopia/métodos , Procedimentos Cirúrgicos Otológicos/métodos , Ácido Tranexâmico/uso terapêutico , Adolescente , Adulto , Pontos de Referência Anatômicos/cirurgia , Perda Sanguínea Cirúrgica/prevenção & controle , Método Duplo-Cego , Meato Acústico Externo/anatomia & histologia , Feminino , Hemostasia Cirúrgica/métodos , Humanos , Período Intraoperatório , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Objective: To identify high risk HPV associations by evaluating linked p16 overexpression and also the expression of p53 and RARß together with histopathology for risk categorization of cervical pre-neoplastic lesions. Materials and Methods: Immunohistochemical staining was performed on 100 cases of cervical pre- neoplastic lesions for expression of biomarkers like p16, p53 and RARß for comparison with haematoxylin/eosin (HE) findings. All the experimentally generated data were statistically analyzed. Results: In this study 70% cases showed overexpression of p16INK4A increasing progressively from CIN I to CIN II but reduced in CIN III (p <0.01). p53 oncoprotein expression was seen in 51% cases, again with increments from CIN I to CIN II with slight reduction in CIN III (p<0.01). Some 24% cases showed negative immunoreactivity for the putative tumor suppressor gene RARß (p>0.05). Conclusion: Our study provides support for the idea that p16 can be used to identify associations with HPV , as well as having potential along with p53 and RARß for categorizing cervical pre-neoplastic cases having a higher risk of neoplastic conversion. Thus it may be concluded that accurate risk categorization can be achieved with the help of genetic markers as well as histopathology.
Assuntos
Biomarcadores Tumorais/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Infecções por Papillomavirus/complicações , Lesões Pré-Cancerosas/patologia , Receptores do Ácido Retinoico/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Neoplasias do Colo do Útero/patologia , Adulto , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/virologia , Lesões Pré-Cancerosas/metabolismo , Lesões Pré-Cancerosas/virologia , Medição de Risco , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/virologia , Adulto Jovem , Displasia do Colo do Útero/metabolismo , Displasia do Colo do Útero/patologia , Displasia do Colo do Útero/virologiaRESUMO
BACKGROUND: Accurate prediction of mastectomy skin flap viability is vital as necrosis causes significant morbidity, potentially compromising results and delaying oncological management. Traditionally assessed by clinical judgement, a more objective evaluation can be provided using intraoperative imaging modalities. This systematic review aimed to compare all intraoperative techniques for assessment of mastectomy flap viability. METHODS: A systematic literature review was performed using MEDLINE and Embase databases. Primary outcomes reported included specificity, sensitivity and predictive values of each test, and mean rates of mastectomy flap necrosis and reoperation. Secondary outcomes included cost analysis. RESULTS: Some 18 studies were included. Designs were prospective cohort study (8), retrospective case series (4), prospective case series (3), retrospective case-control study (1), prospective pilot trial (1) and cost analysis study (1). The studies compared indocyanine green angiography (ICGA) (16 studies) and fluorescein dye angiography (FA) (3 studies) with clinical judgement. Sensitivity and specificity were highest for ICGA (5 studies) ranging from 38 to 100 and 68 to 91 per cent respectively. Both methods overpredicted necrosis. Mean rates of flap necrosis and reoperation decreased with ICGA (7·9 and 5·5 per cent respectively) and FA (3 and 0 per cent) compared with clinical judgement (19·4 and 12·9 per cent). Two studies were designed to define numerical parameters corresponding to perfusion using intraoperative techniques. Two studies performed a cost analysis for ICGA; one claimed a cost benefit and the other advocated its use in high-risk patients only. CONCLUSION: ICGA and FA are potentially useful tools for mastectomy flap assessment. However, the predictive accuracy is subject to the specific settings and model of equipment used. Current recommendations support their use in high-risk patients.
RESUMO
Management of viral diseases relies on definite and sensitive detection methods. Citrus yellow mosaic virus (CYMV), a double stranded DNA virus of the genus Badnavirus, causes yellow mosaic disease in citrus plants. CYMV is transmitted through budwood and requires a robust and simplified indexing protocol for budwood certification programme. The present study reports development and standardization of an isothermal based recombinase polymerase amplification (RPA) assay for a sensitive, rapid, easy, and cost-effective method for detection and diagnosis of CYMV. Two different oligonucleotide primer sets were designed from ORF III (coding for polyprotein) and ORF II (coding for virion associated protein) regions of CYMV to perform amplification assays. Comparative evaluation of RPA, PCR and immuno-capture recombinase polymerase amplification (IC-RPA) based assays were done using purified DNA and plant crude sap. CYMV infection was efficiently detected from the crude sap in RPA and IC-RPA assays. The primer set used in RPA was specific and did not show any cross-amplification with banana streak MY virus (BSMYV), another Badnavirus species. The results from the present study indicated that RPA assay can be used easily in routine indexing of citrus planting material. To the best of our knowledge, this is the first report on development of a rapid and simplified isothermal detection assay for CYMV and can be utilized as an effective technique in quarantine and budwood certification process.
Assuntos
Citrus/virologia , Vírus do Mosaico/isolamento & purificação , Doenças das Plantas/virologia , Recombinases/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The present study was undertaken to determine the mechanism of antibacterial activity of a polyphenolic fraction, composed of mainly catechin and isorhamnetin, previously isolated from Kombucha, a 14-day fermented beverage of sugared black tea, against the enteropathogen Vibrio cholerae N16961. Bacterial growth was found to be seriously impaired by the polyphenolic fraction in a dose-dependent manner. Scanning Electron Microscopy demonstrated morphological alterations in bacterial cells when exposed to the polyphenolic fraction in a concentration-dependent manner. Permeabilization assays confirmed that the fraction disrupted bacterial membrane integrity in both time- and dose-dependent manners, which were proportional to the production of intracellular reactive oxygen species (ROS). Furthermore, each of the polyphenols catechin and isorhamnetin showed the ability to permeate bacterial cell membranes by generating oxidative stress, thereby suggesting their role in the antibacterial potential of Kombucha. Thus, the basic mechanism of antibacterial activity of the Kombucha polyphenolic fraction against V. cholerae involved bacterial membrane permeabilization and morphological changes, which might be due to the generation of intracellular ROS. To the best of our knowledge, this is the first report on the investigation of antibacterial mechanism of Kombucha, which is mostly attributed to its polyphenolic content. SIGNIFICANCE AND IMPACT OF THE STUDY: The emergence of multidrug-resistant Vibrio cholerae strains has hindered an efficient anti-Vibrio therapy. This study has demonstrated the membrane damage-mediated antibacterial mechanism of Kombucha, a popular fermented beverage of sugared tea, which is mostly attributed to its polyphenolic content. This study also implies the exploitation of Kombucha as a potential new source of bioactive polyphenols against V. cholerae.