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BACKGROUND: Coronaviruses have the potential to cross species barriers. To learn the molecular intersections among the most common coronaviruses of domestic and close-contact animals, we analyzed representative coronavirus genera infecting mouse, rat, rabbit, dog, cat, cattle, white-tailed deer, swine, ferret, mink, alpaca, Rhinolophus bat, dolphin, whale, chicken, duck and turkey hosts; reference or complete genome sequences were available for most of these coronavirus genera. Protein sequence alignments and phylogenetic trees were built for the spike (S), envelope (E), membrane (M) and nucleocapsid (N) proteins. The host receptors and enzymes aminopeptidase N (APN), angiotensin converting enzyme 2 (ACE2), sialic acid synthase (SAS), transmembrane serine protease 2 (TMPRSS2), dipeptidyl peptidase 4 (DPP4), cathepsin L (and its analogs) and furin were also compared. RESULTS: Overall, the S, E, M, and N proteins segregated according to their viral genera (α, ß, or γ), but the S proteins of alphacoronaviruses lacked conservation of phylogeny. Interestingly, the unique polybasic furin cleavage motif found in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) but not in severe acute respiratory syndrome coronavirus (SARS-CoV) or Middle East respiratory syndrome coronavirus (MERS-CoV) exists in several ß-coronaviruses and a few α- or γ-coronaviruses. Receptors and enzymes retained host species-dependent relationships with one another. Among the hosts, critical ACE2 residues essential for SARS-CoV-2 spike protein binding were most conserved in white-tailed deer and cattle. CONCLUSION: The polybasic furin cleavage motif found in several ß- and other coronaviruses of animals points to the existence of an intermediate host for SARS-CoV-2, and it also offers a counternarrative to the theory of a laboratory-engineered virus. Generally, the S proteins of coronaviruses show crossovers of phylogenies indicative of recombination events. Additionally, the consistency in the segregation of viral proteins of the MERS-like coronavirus (NC_034440.1) from pipistrelle bat supports its classification as a ß-coronavirus. Finally, similarities in host enzymes and receptors did not always explain natural cross-infections. More studies are therefore needed to identify factors that determine the cross-species infectivity of coronaviruses.
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COVID-19 , Enfermedades de los Bovinos , Ciervos , Enfermedades de los Perros , Coronavirus del Síndrome Respiratorio de Oriente Medio , Enfermedades de los Roedores , Enfermedades de los Porcinos , Animales , COVID-19/veterinaria , Bovinos , Perros , Hurones , Ratones , Coronavirus del Síndrome Respiratorio de Oriente Medio/genética , Filogenia , Conejos , Ratas , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , PorcinosRESUMEN
BACKGROUND: The poultry industry in Egypt has been suffering from endemic highly pathogenic avian influenza (HPAI) virus, subtype H5N1 since 2006. However, the emergence of H9N2, H5N8, and H5N2 in 2011, 2016, and 2019 respectively, has aggravated the situation. Our objective was to evaluate how effective are the mitigation strategies by a Quantitative Risk Assessment (QRA) model which used daily outbreak data of HPAI-H5N1 subtype in Egypt, stratified by different successive epidemic waves from 2006 to 2016. RESULTS: By applying the epidemiologic problem-oriented approach methodology, a conceptual scenario tree was drawn based on the knowledgebase. Monte Carlo simulations of QRA parameters based on outbreak data were performed using @Risk software based on a scenario-driven decision tree. In poultry farms, the expected probability of HPAI H5N1 prevalence is 48% due to failure of mitigation strategies in 90% of the time during Monte Carlo simulations. Failure of efficacy of these mitigations will raise prevalence to 70% with missed vaccination, while failure in detection by surveillance activities will raise it to 99%. In backyard poultry farms, the likelihood of still having a high HPAI-H5N1 prevalence in different poultry types due to failure of passive and active surveillance varies between domestic, mixed and reservoir. In mixed poultry, the probability of HPAI-H5N1 not detected by surveillance was the highest with a mean and a SD of 16.8 × 10-3 and 3.26 × 10-01 respectively. The sensitivity analysis ranking for the likelihood of HPAI-H5N1 in poultry farms due to missed vaccination, failure to be detected by passive and active surveillance was examined. Among poultry farms, increasing vaccination by 1 SD will decrease the prevalence by 14%, while active and passive surveillance decreases prevalence by 12, and 6%, respectively. In backyard, the active surveillance had high impact in decreasing the prevalence by 16% in domestic chicken. Whereas the passive surveillance had less impact in decreasing prevalence by 14% in mixed poultry and 3% in domestic chicken. CONCLUSION: It could be concluded that the applied strategies were not effective in controlling the spread of the HPAI-H5N1 virus. Public health officials should take into consideration the evaluation of their control strategies in their response.
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Pollos , Subtipo H5N1 del Virus de la Influenza A , Vacunas contra la Influenza/administración & dosificación , Gripe Aviar/prevención & control , Enfermedades de las Aves de Corral/prevención & control , Animales , Pollos/virología , Brotes de Enfermedades/prevención & control , Brotes de Enfermedades/veterinaria , Egipto/epidemiología , Gripe Aviar/epidemiología , Gripe Aviar/virología , Modelos Biológicos , Método de Montecarlo , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/virología , Prevalencia , Medición de RiesgoRESUMEN
Fish processing industries generate large quantities of fish scales as processing waste, if not treated leading to environmental pollution. Fish scales are hard to degrade, hence cause difficulty in waste management. In this context present study was made to utilize fish scales as substrate for the production of alkaline protease by Bacillus altitudinis GVC11 and subsequently amino acid rich aqua hydrolyzate. B. altitudinis GVC11 efficiently utilized five types of fish scales as substrates and produced maximum alkaline protease using Labeo rohita (28,150 U/mL) followed by Catla catla (23,320 U/mL) at 48 h and Cyprinus carpio (17,146 U/mL) Mugil cephalus (18,917 U/mL), Cirrhinus mrigala (12,430 U/mL) at 72 h. The HPLC analysis of protein hydrolyzate obtained after fermentation was enriched in essential amino acids, leucine, isoleucine, phenylalanine, lysine and non-essential amino acids, tyrosine, arginine and cysteine which can be used as animal feed supplement and organic fertilizer.
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Dengue is the most rapidly spreading mosquito-borne viral disease in the world, and as a larger proportion of the population is being affected, more unusual manifestations are being reported. Very few studies have documented unusual manifestations of dengue in South India. This prospective study was undertaken from July 2011 to June 2013 to document rare manifestations of dengue fever in 175 hospitalized patients. The clinical diagnosis was confirmed by the detection of NS1Ag, dengue IgM, or IgG by ELISA and/or a RT-PCR and CDC real-time PCR for dengue virus (DENV) RNA. The daily profiles of the hematological and biochemical investigations were followed and recorded. Unusual and rare manifestations of dengue were documented for 115 patients (66 %). Hepatitis was observed in 70 % of the cases. Pleural effusion was seen in 11 %, acute renal failure in 10 %, neurological complications such as encephalitis in 7.4 %, myocarditis in 9 %, and bleeding gastric ulcers in 3.4 % of the cases. DENV serotype 2 was more prevalent in patients with unusual manifestations of dengue in our study. The WHO classification system does not include unusual and rare manifestations; hence, it is essential to be aware of these manifestations and closely monitor them for better clinical management and outcome of patients.
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Dengue/complicaciones , Dengue/epidemiología , Brotes de Enfermedades , Centros de Atención Terciaria , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antivirales/sangre , Dengue/mortalidad , Virus del Dengue/genética , Virus del Dengue/inmunología , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , India/epidemiología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , ARN Viral/sangre , ARN Viral/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Serotipificación , Adulto JovenRESUMEN
We analyzed the length of the CAG repeats of the androgen receptor gene in Indian women with breast cancer, and compared the data with that of other populations across the world in an attempt to find a potential pattern of association. The study was undertaken on 1,408 individuals comprising 747 breast cancer patients and 661 control individuals recruited from three southern states of India: Andhra Pradesh, Tamil Nadu, and Karnataka. The comparison revealed no difference in mean length of the repeat between cases and controls in any of the three groups or in the analysis of pooled data. No significant difference between pre- and post-menopausal cases in any of the three groups or in the analysis of pooled data was observed. Most of the studies to date support either positive association (longer repeats--increased disease risk) or no association, and only 2 out of 20 studies reported negative association (inverse correlation between repeat length and disease risk). Comparison of these data with those from other populations revealed several interesting facts. Particularly notable is that repeat length shows association with breast cancer risk in a population-specific manner with most of the studies on American and Canadian women showing positive association, whereas those on Australian and Israeli women showing no association. Only one study had been conducted on other populations including Asians/South Asians; this restricted us from finding any patterns of association in these populations.
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Neoplasias de la Mama/genética , Estudios de Asociación Genética , Polimorfismo Genético , Receptores Androgénicos/genética , Secuencias Repetidas en Tándem , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Andrógenos/genética , Femenino , Predisposición Genética a la Enfermedad , Humanos , India , Persona de Mediana Edad , Factores de RiesgoRESUMEN
A serine alkaline protease from a newly isolated alkaliphilic Bacillus altitudinis GVC11 was purified and characterized. The enzyme was purified to homogeneity by acetone precipitation, DEAE-cellulose anion exchange chromatography with 7.03-fold increase in specific activity and 15.25% recovery. The molecular weight of alkaline protease was estimated to be 28 kDa by SDS PAGE and activity was further assessed by zymogram analysis. The enzyme was highly active over a wide range of pH 8.5 to 12.5 with an optimum pH of 9.5. The optimum temperature of purified enzyme was 45 °C and Ca(2+) further increased the thermal stability of the enzyme. The enzyme activity was enhanced by Ca(2+) and Mg(2+) and inhibited by Hg(2+). The present study is the first report to examine and describe production of highly alkaline protease from Bacillus altitudinis and also its remarkable dehairing ability of goat hide in 18 h without disturbing the collagen and hair integrity.
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Bacillus/enzimología , Proteínas Bacterianas/química , Endopeptidasas/química , Curtiembre/métodos , Animales , Biotecnología/métodos , Calcio/química , Electroforesis en Gel de Poliacrilamida , Fermentación , Cabras , Cabello , Concentración de Iones de Hidrógeno , Iones , Magnesio/química , Mercurio/química , TemperaturaRESUMEN
The objective of this study was to evaluate the effect of varying levels of hempseed meal supplementation on antibody and cell-mediated immune responses, as well as the expression of some of the important immunoregulatory cytokines. Treatments consisted of hempseed meal supplementation at 0 (control), 10, 20, and 30% of the total diet. Goats were randomly assigned to one of the four treatments n = 10. Cell-mediated immune response was evaluated on day 59 of the feeding period by measuring skinfold thickness at 24 h following intradermal injection of phytohemagglutinin. A significant increase in skinfold thickness was observed with increasing levels of supplementation as compared to that of the control group. Serum antibody titers to chicken ovalbumin were not significantly different between treatment groups. Cytokine concentrations of IL-6 increased linearly with increasing level of supplementation (p < 0.05), contrarily to the linear decrease that was observed for TNF-α (p < 0.05). Although IL-2 tended to increase with the 10 and 30% levels of supplementation (p < 0.07), the result was not significant, and no significant differences were obtained with respect to IL-4 concentrations. Cytokine gene expression values measured by RT-PCR, however, demonstrated some significant differences. HSM supplementation had no significant effect on the expression of IL-2 or IL-6. However, significant differences were observed with the 30% supplementation for IL-4 and TNF-α as compared to that of the control group (p < 0.05). IL-4 was down regulated for the 10 and 20% treatment groups but was upregulated for the 30% treatment group. TNF-α was downregulated in the 10% but upregulated for the 20 and 30% treatment groups. No significant differences were observed for the serum cortisol concentration or white blood cell counts. These results suggested that hempseed meal supplementation may improve cell-mediated immune response while having no effect on antibody-mediated immune response. However, more research needs to be conducted to determine the most efficacious inclusion rate.
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In this study we isolated and screened drought tolerant Pseudomonas isolates from arid and semi arid crop production systems of India. Five isolates could tolerate osmotic stress up to -0.73 MPa and possessed multiple PGP properties such as P-solubilization, production of phytohormones (IAA, GA and cytokinin), siderophores, ammonia and HCN however under osmotic stress expression of PGP traits was low compared to non-stressed conditions. The strains were identified as Pseudomonas entomophila, Pseudomonas stutzeri, Pseudomonas putida, Pseudomonas syringae and Pseudomonas monteilli respectively on the basis of 16S rRNA gene sequence analysis. Osmotic stress affected growth pattern of all the isolates as indicated by increased mean generation time. An increase level of intracellular free amino acids, proline, total soluble sugars and exopolysaccharides was observed under osmotic stress suggesting bacterial response to applied stress. Further, strains GAP-P45 and GRFHYTP52 showing higher levels of EPS and osmolytes (amino acids and proline) accumulation under stress as compared to non-stress conditions, also exhibited higher expression of PGP traits under stress indicating a relationship between stress response and expression of PGP traits. We conclude that isolation and screening of indigenous, stress adaptable strains possessing PGP traits can be a method for selection of efficient stress tolerant PGPR strains.
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Ósmosis , Reguladores del Crecimiento de las Plantas/metabolismo , Plantas/microbiología , Pseudomonas/metabolismo , Microbiología del Suelo , Amoníaco/metabolismo , India , Ácidos Indolacéticos/metabolismo , Desarrollo de la Planta , Plantas/metabolismo , Pseudomonas/crecimiento & desarrollo , Pseudomonas/aislamiento & purificación , Sideróforos/metabolismo , Estrés FisiológicoRESUMEN
Pectin rich wastes and waste dump yard soils were screened and eighty pectinolytic fungal isolates were obtained by enrichment culturing and ruthenium red plate assay. Eight isolates with higher zones of pectin hydrolysis were selected and tested for polygalacturonase production. One isolate identified as Aspergillus awamori MTCC 9166 with highest polygalacturonase activity was tested for utilization of raw pectins for enzyme production. Polygalacturonase production was high in raw pectin sources like Orange peel (16.8 U/ml) Jack fruit rind (38 U/ml) Carrot peel (36U/ml) and Beet root peel (24U/ml). Selected Aspergillus awamori MTCC 9166 was found to be having good polygalacturonase, xylanase, cellulase and weak amylase and protease activities. This isolate with multi-enzyme production could have application for enzymes production and degradation of fruit and vegetable waste in the process of urban waste disposal.
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ß-d-fructofuranosidase is one of the most important enzymes of the food industry especially due to its application in preparation of soft centered candies, confectioneries and to produce fructose syrups. Although several bacteria and filamentous fungi are reported for its production, yeasts are the most preferred source for this enzyme. In the present study mineral nutrients were screened for their effect on yeast growth and the enzyme production using Plackett-Burman design. Of the 11 nutrients screened, three variables (KH(2)PO(4), FeCl(3) and CoCl(2)) were significantly effecting yeast growth while six variables, i.e. KH(2)PO(4), CaCl(2), MnSO(4), Na(2)MoO(4), ZnSO(4) and CoCl(2) had significant effect on enzyme production.
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Long endemicity of the Highly Pathogenic Avian Influenza (HPAI) H5N1 subtype in Egypt poses a lot of threats to public health. Contrary to what is previously known, outbreaks have been circulated continuously in the poultry sectors all year round without seasonality. These changes call the need for epidemiological studies to prove or deny the influence of climate variability on outbreak occurrence, which is the aim of this study. This work proposes a modern approach to examine the degree to which the HPAI-H5N1disease event is being influenced by climate variability as a potential risk factor using generalized estimating equations (GEEs). GEE model revealed that the effect of climate variability differs according to the timing of the outbreak occurrence. Temperature and relative humidity could have both positive and negative effects on disease events. During the cold seasons especially in the first quarter, higher minimum temperatures, consistently show higher risks of disease occurrence, because this condition stimulates viral activity, while lower minimum temperatures support virus survival in the other quarters of the year with the highest negative effect in the third quarter. On the other hand, relative humidity negatively affects the outbreak in the first quarter of the year as the humid weather does not support viral circulation, while the highest positive effect was found in the second quarter during which low humidity favors the disease event.
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Brotes de Enfermedades/veterinaria , Subtipo H5N1 del Virus de la Influenza A/patogenicidad , Gripe Aviar/epidemiología , Animales , Cambio Climático , Egipto/epidemiología , Aves de Corral , Factores de RiesgoRESUMEN
[This corrects the article DOI: 10.1371/journal.pone.0240442.].
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Lactic acid, an enigmatic chemical has wide applications in food, pharmaceutical, leather, textile industries and as chemical feed stock. Novel applications in synthesis of biodegradable plastics have increased the demand for lactic acid. Microbial fermentations are preferred over chemical synthesis of lactic acid due to various factors. Refined sugars, though costly, are the choice substrates for lactic acid production using Lactobacillus sps. Complex natural starchy raw materials used for production of lactic acid involve pretreatment by gelatinization and liquefaction followed by enzymatic saccharification to glucose and subsequent conversion of glucose to lactic acid by Lactobacillus fermentation. Direct conversion of starchy biomass to lactic acid by bacteria possessing both amylolytic and lactic acid producing character will eliminate the two step process to make it economical. Very few amylolytic lactic acid bacteria with high potential to produce lactic acid at high substrate concentrations are reported till date. In this view, a search has been made for various amylolytic LAB involved in production of lactic acid and utilization of cheaply available renewable agricultural starchy biomass. Lactobacillus amylophilus GV6 is an efficient and widely studied amylolytic lactic acid producing bacteria capable of utilizing inexpensive carbon and nitrogen substrates with high lactic acid production efficiency. This is the first review on amylolytic bacterial lactic acid fermentations till date.
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Fermentación , Ácido Láctico/metabolismo , Lactobacillus/metabolismo , Almidón/metabolismo , Lactobacillus/enzimología , Lactobacillus/ultraestructura , Almidón/ultraestructura , Especificidad por SustratoRESUMEN
Five bacterial strains with phosphate-solubilizing ability and other plant growth promoting traits increased the plant biomass (20-40%) by paper towel method. Glasshouse and field experiments were conducted using two efficient strains Serratia marcescens EB 67 and Pseudomonas sp. CDB 35. Increase in plant biomass (dry weight) was 99% with EB 67 and 94% with CDB 35 under glasshouse conditions. Increase in plant biomass at 48 and 96 days after sowing was 66% and 50% with EB 67 and 51% and 18% with CDB 35 under field conditions. Seed treatment with EB 67 and CDB 35 increased the grain yield of field-grown maize by 85% and 64% compared to the uninoculated control. Population of EB 67 and CDB 35 were traced back from the rhizosphere of maize on buffered rock phosphate (RP) medium and both the strains survived up to 96 days after sowing.
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Fosfatos/metabolismo , Pseudomonas/metabolismo , Serratia marcescens/metabolismo , Microbiología del Suelo , Zea mays/microbiología , Biomasa , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Pseudomonas/crecimiento & desarrollo , Pseudomonas/aislamiento & purificación , Semillas/crecimiento & desarrollo , Semillas/microbiología , Serratia marcescens/crecimiento & desarrollo , Serratia marcescens/aislamiento & purificación , Zea mays/crecimiento & desarrolloRESUMEN
Saccharomyces cerevisiae which cannot utilize lysine as a sole nitrogen source is shown to metabolize a Lysine 3 Cr(3+) (1:1) complex synthesized, as a combined nitrogen and carbon source. It induces rapid uptake of lysine and prevents loss of viability, in contrast with free lysine. That complexation with trivalent chromium has the effect of profoundly influencing intracellular distribution and metabolism of the liganded amino acid is demonstrated.
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L(+) Lactic acid fermentation was studied by Lactobacillus amylophilus GV6 under the influence of inexpensive nitrogen sources (red lentil-RL, and Baker's yeast cells-YC) and starch by response surface methodology (RSM). Central composite rotatable design (CCRD) was employed to determine maximum lactic acid production at optimum values for process variables RL, YC and incubation period (IP) and a satisfactory fit model was realized. Lactic acid production was significantly affected by RL and IP interactions as well as by independent variables RL and YC. Maximum lactic acid production of 13.5 g/15.2g starch was obtained with RL 0.8%, YC 1% and IP of 48 h, with 92% lactic acid yield efficiency (g lactic acid produced/g substrate utilized) and 40% increase (from 50 g to 92 g/100 g starch utilized) in lactic acid production. This is the first report on response optimization in direct fermentation of starch to lactic acid using inexpensive nitrogen sources substituting peptone and yeast extract in anaerobic submerged fermentation by amylolytic lactic acid bacteria (LAB).
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Ácido Láctico/metabolismo , Lactobacillus/metabolismo , Nitrógeno/metabolismo , Almidón/metabolismo , Anaerobiosis , Fermentación , Lens (Planta)/química , Lens (Planta)/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismoRESUMEN
An effecient feather-degrading bacterium was isolated from poultry dumping yard and identified as Bacillus pumilus GRK based on 16S rRNA sequencing. Complete feather degradation (98.3±1.52%) with high keratinase production (373±4 U/ml) was observed in 24h under optimized conditions (substrate 1% (w/w); inoculum size 4% (v/v); pH 10; 200rpm at 37°C) with feathers as sole carbon and nitrogen source in tap water. The fermented broth was enriched with amino acids like tryptophan (221.44µg/ml), isoleucine (15.0µg/ml), lysine (10.81µg/ml) and methionine (7.24µg/ml) suggesting its potential use as feed supplement. The keratinase produced was a detergent stable serine protease and its activity was further enhanced by Ca+2 and Mg+2. Bacillus pumilus GRK keratinase was successfully utilised as bioadditive in detergent formulations for removing the blood stains from cloth without affecting its fiber and texture.
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Bacillus pumilus , Plumas , Péptido Hidrolasas , Animales , Bacillus , Detergentes , Concentración de Iones de Hidrógeno , ARN Ribosómico 16SRESUMEN
Biosurfactants are secondary metabolites with surface active properties and have wide application in agriculture, industrial and therapeutic products. The present study was aimed to screen bacteria for the production of biosurfactant, its characterization and development of a cost effective media formulation for iturin A production. A total of 100 bacterial isolates were isolated from different rhizosphere soil samples by enrichment culture method and screened for biosurfactant activity. Twenty isolates were selected for further studies based on their biosurfactant activity [emulsification index (EI%), emulsification assay (EA), surface tension (ST) reduction] and antagonistic activity. Among them one potential isolate Bacillus sp. RHNK22 showed good EI% and EA with different hydrocarbons tested in this study. Using biochemical methods and 16S rRNA gene sequence, it was identified as Bacillus amyloliquefaciens. Presence of iturin A in RHNK22 was identified by gene specific primers and confirmed as iturin A by FTIR and HPLC. B. amyloliquefaciens RHNK22 exhibited good surface active properties and antifungal activity against Sclerotium rolfsii and Macrophomina phaseolina. For cost-effective production of iturin A, 16 different agro-industrial wastes were screened as substrates, and Sunflower oil cake (SOC) was favouring high iturin A production. Further, using response surface methodology (RSM) model, there was a 3-fold increase in iturin A production (using SOC 4%, inoculum size 1%, at pH 6.0 and 37 °C temperature in 48 h). This is the first report on using SOC as a substrate for iturin A production.
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A novel genomic and plasmid target-based PCR platform was developed for the detection of Salmonella serovars Heidelberg, Dublin, Hadar, Kentucky, and Enteritidis. Unique genome loci were obtained through extensive genome mining of protein databases and comparative genomic analysis of these serovars. Assays targeting Salmonella serovars Hadar, Heidelberg, Kentucky, and Dublin had 100% specificity and sensitivity, whereas those for Salmonella Enteritidis had 97% specificity and 88% sensitivity. The limits of detection for Salmonella serovars Heidelberg, Kentucky, Hadar, Enteritidis, and Dublin were 12, 9, 40, 13, and 5,280 CFU, respectively. A sensitivity assay was also performed by using milk artificially inoculated with pooled Salmonella serovars, yielding a detection limit of 1 to10 CFU/25 mL of milk samples after enrichment. The minimum DNA detected using the multiplexed TaqMan assay was 75.8 fg (1.53 × 101 genomic equivalents [GE]) for Salmonella Heidelberg, 140.8 fg (2.8 × 101 GE) for Salmonella Enteritidis, and 3.48 pg (6.96 × 102 GE) for Salmonella Dublin. PCR efficiencies were 89.8% for Salmonella Heidelberg, 94.5% for Salmonella Enteritidis, and 75.5% for Salmonella Dublin. Four types of 30 pasteurized milk samples were tested negative by culture techniques and with a genus-specific Salmonella invA gene PCR assay. Among 30 chicken samples similarly tested, 12 (40%) were positive by both culture and the invA PCR. Testing of these 12 samples with the serovar-specific PCR assay detected single and mixed contamination with Salmonella Kentucky, Salmonella Enteritidis, and Salmonella Heidelberg. Five unique primers were designed and tested by multiplex conventional PCR in conjunction with the use of the multiplex TaqMan assay with three of the primers. The diagnostic assays developed in this study could be used as tools for routine detection of these five Salmonella serovars and for epidemiological investigations of foodborne disease outbreaks.
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Beneficial aspects of endophytic microorganisms have motivated researchers to explore plant endophytic world. The present study was aimed to isolate and characterize the seed-borne endophytic bacteria from diverse maize genotypes. Eighty maize seed endophytic bacteria (MSEB), isolated from 30 maize genotypes, were characterized using polyphasic approach. The dendrograms and phylogenetic tree generated on the basis of ARDRA analysis and metabolic profiling of endophytic bacteria revealed genotypic and biochemical diversity among MSEB. The 16S rDNA sequence analysis revealed Bacillus as the most dominant encountered genus affiliated with Phylum Firmicutes. Few isolates belonged to genus Staphylococcus, whereas one isolate was identified as Corynebacterium sp. under Phylum Actinobacteria. Majority of the MSEB isolates exhibited antagonism against phytopathogenic fungi, production of ammonia, and secretion of lytic enzymes; some isolates also exhibited indole acetic acid production, the traits of which can be helpful in endophytic establishment and advantageous to the host plant. Besides, many MSEB exhibited tolerance to salinity (10%), osmotic stress (40% PEG6000), and temperature (60 °C), indicating their possible application under stress conditions. Endophytic nature of the selected MSEB isolates was confirmed by tracking their presence in shoots, leaves, and roots of the host seedlings with the help of biochemical marker (rifampicin resistance). Thus, the MSEB identified in the present study can be explored as potential bioinputs for improving plant growth and productivity under stressed conditions, besides helping in understanding the plant-endophyte interactions.