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The present work was designed to isolate and characterise the actinobacteria in the Polar Front region of the Southern Ocean waters and species of Nocardiopsis and Streptomyces were identified. Among those, the psychrophilic actinobacterium, Nocardiopsis dassonvillei PSY13 was found to have good cellulolytic activity and it was further studied for the production and characterisation of cold-active cellulase enzyme. The latter was found to have a specific activity of 6.36 U/mg and a molar mass of 48 kDa with a 22.9-fold purification and 5% recovery at an optimum pH of 7.5 and a temperature of 10 °C. Given the importance of psychrophilic actinobacteria, N. dassonvillei PSY13 can be further exploited for its benefits, meaning that the Southern Ocean harbours biotechnologically important microorganisms that can be further explored for versatile biotechnological and industrial applications.

BackgroundIn the present study, hexane: methanol (50:50) leaf extract of Marisela minuta has been evaluated for its chemical composition, antioxidant effect and the antimicrobial mechanism of action against food borne pathogenic bacteria.ResultsThe phytochemical evaluation of extract by GC/MS revealed the major abundance of benzoic acid-4-ethoxyethyl ester (43.39%) and farnesol acetate (18.42%). The extract exhibited potential antioxidant and free radical scavenging properties with promising antibacterial activities against the test pathogens with Pseudomonas aeruginosa being the most susceptible with maximum inhibition zone (17 mm) and IC50 value of 125 µg, respectively. The significant (p < 0.05) increase in intracellular super oxide dismutase (SOD), protein leakage, extracellular alkaline phosphatase and lactate dehydrogenase in treated test pathogens suggested an increase in oxidative stress reveling the mechanism of action of phytochemicals. Scanning electron microscopy analysis of treated pathogens also showed swollen and distorted cells. The bioactive molecules in the extract were efficiently docked with virulent enzymes and farnesol acetate showed best energy value of − 5.19 and − 4.27 kcal/mol towards Topoisomerase IV and SHV-2 respectively. Benzoic acid-4-ethoxyethyl ester showed best binding against TEM-72 with low binding energy value of − 4.35 kcal/mol.ConclusionDue to its antioxidant and antibacterial properties, the leaf extract of M. minuta may act as promising natural additives to prevent food spoilage bacteria.

A total of five pectin-rich banana peels, including those of two Musa paradisiaca cultivars (nendran and kadali) and three Musa acuminata varieties (matti, palayankodan, and robusta), were used for pectinase production by Aspergillus flavus via solid-state fermentation (SSF). Comparative analysis revealed highest pectin content in the palayankodan peel (18.09 ± 0.29%). The palayankodan peel variety presented 135 ± 2.2 U/gds pectinase activity in SSF using A. flavus, whereas robusta peels presented 108 ± 1.9 U/gds pectinase activity in SSF. A one-factor-at-a-time experiment was performed, and the variables moisture, pH, and fermentation period affected enzyme production. A central composite design was used to optimize pectinase production in SSF via three prominent variables (moisture content, pH, and fermentation period). The experimental result was statistically significant (p<0.01), and twofold enzyme production was achieved. The crude pectinase was extracted from the fermented medium and used as a clarifying agent. The pectinase-treated orange juice presented a decreased turbidity compared to the untreated control. The amount of total sugar and total suspended solids was reduced, whereas the total pH increased. Therefore, the A. flavus strain can be utilized for large-scale production of pectinase, which could meet the growing industry demands.

Few studies have examined the effects of feeding total mixed ration (TMR) versus roughage and concentrate separately (SF) on ruminant methane production. Therefore, this study compared differences in methane production, ruminal characteristics, total tract digestibility of nutrients, and rumen microbiome between the two feeding methods in Holstein steers. A total six Holstein steers of initial bodyweights 540 ± 34 kg were divided into two groups and assigned to a same experimental diet with two different feeding systems (TMR or SF) in a crossover design with 21 d periods. The experimental diet contained 73% concentrate and 27% forage and were fed twice a day. The total tract digestibility of crude protein, neutral detergent fibre, and organic matter were not affected by the two different feeding systems. Steers fed TMR emitted more methane (138.5 vs. 118.2 L/d; P < 0.05) and lost more gross energy as methane energy (4.0 vs. 3.5% gross energy intake; P = 0.005) compared to those fed SF. Steers fed TMR had greater (P < 0.05) total volatile fatty acid (VFA), ammonia-N concentrations and propionate proportion of total VFA at 1.5 h, whereas lower after that compared to steers fed SF. The greater (P < 0.05) acetate: propionate ratio at 4.5 h for steers fed TMR reflected the shift of H2 sink from propionate towards acetate synthesis. The lower (P < 0.05) isobutyrate and isovalerate proportions of total VFA observed in steers fed TMR implies decrease in net consumption of H2 for microbial protein synthesis compared to SF. There were no differences in both major bacterial and archaeal diversity between TMR and SF, unlike several minor bacterial abundances. The minor groups such as Coprococcus, Succiniclasticum, Butyrivibrio, and Succinivibrio were associated with the changes in ruminal VFA profiles or methanogenesis indirectly. Overall, these results indicate that SF reduces methane emissions from ruminants and increases propionate proportion of total VFA without affecting total tract digestion compared to TMR. There were no evidences that the response differed due to different major underlying microbial population.

The study aim was to optimise the C/N ratio, improve the compost quality, reduce pathogenic bacteria load in the compost, and improve guava yield. Vegetable wastes were mixed with cow dung, grasses, and food wastes in ratios of 4:3:2:1 (w/w) for achieving a C/N ratio of approximately 37. Co-composting is an important strategy because the mixture of bulking agents can help achieve optimal composting conditions. Experimental results were obtained from a pilot-scale rotary drum reactor with forced aeration. In the reactor, the temperature increased during the thermophilic phase (58±2 °C) and decreased after 10 days (54±2 °C). The pH values moderately increased, then decreased, and were near to neutral after maturation. The results indicated that co-composting of bio-wastes at a C/N ratio of 37.6%±1.02% could be effectively decomposed to reduce the residuals to just 13.6%±1.05% after 28 days. The microbial population increased in both mesophilic and thermophilic stages and decreased at the end of the composting, reflecting stability. The stable compost was applied to the growth of guava plant, and the yield was calculated. The organic compost improved plant growth, fruit yield, and enriched phytochemical compounds in the fruit and peels. The phytochemical compounds improved antioxidant activity in the guava fruits.

The present study aimed to identify the cervical microbes that are associated with HPV negativity, HPV clearance and HPV persistence and to assess the microbes’ longitudinal associations as related to HPV infection dynamics among Korean women. We enrolled 41 women with 107 samples, and classified them according to the HPV infection dynamics: HPV negativity (21 samples, 10 subjects), HPV clearance (42 samples, 15 subjects), and HPV persistence (44 samples, 16 subjects). Cervical swabs were collected at the baseline and six-month-interval follow-up visits. HPV positivity was determined by HPV DNA HC2 assay, and the microbiome was analyzed using 16SrRNA pyrosequencing, linear discriminant analysis effect size and multivariate logistic analysis. In the multivariate logistic analysis results, Lactobacillus crispatus (multivariate OR (mOR) = 8.25, 95% CI 2.13~32.0) was predominant in the HPV-negative group. We observed that Eubacterium eligens (mOR = 11.5, 95% CI 1.31~101.4), Gardnerella vaginalis (mOR = 17.0, 95% CI 2.18–131.8), and Ureaplasma urealyticum (mOR = 7.42, 95% CI 1.3–42.46) had the strongest associations with HPV clearance, and Lactobacillus johnsonii (mOR = 16.4, 95% CI 1.77–152.2) with HPV persistence. Overall, greater diversity was observed in HPV-persistence than in HPV-negative women. Our findings suggest that the presence and prevalence of a specific cervical microbiome are factors involved in HPV dynamics.

Lignocellulosic residues (guava leaves, cabbage leaves, pineapple peels, pomegranate peels, orange peels, banana pseudostem, and wheat bran) were used for the production of laccase (LaC) and lignin peroxidase (LiP) via solid-state fermentation (SSF) by fungi (Cerrena unicolor and Loweporus lividus). The results revealed that banana pseudostems presented higher LaC and LiP activities (49.8±1.4 U/g and 7.8±0.24 U/g, respectively) than other agricultural residues did. Banana pseudostems presented increased amounts of lignin (21±0.28%), cellulose (42.8±0.92%), and hemicelluloses (22.3±0.14%), which stimulated enzyme production. The data revealed that glucose (a carbon source), ammonium sulfate (a nitrogen source), an inducer (polysorbate 80, 0.15%), a pH of 4.5, and a 60% moisture content were optimal for LaC and LiP production. Two-level full factorial designs revealed that the variables moisture, pH, polysorbate 80, and glucose significantly influenced LaC and LiP production (p<0.001). A central composite design was applied to optimize the medium components, and glucose and polysorbate 80 influenced LaC and LiP production. The optimized medium (4.82 pH, 0.13% polysorbate 80, and 0.57% glucose) improved LaC (151.9 U/g) and LiP (19.2 U/g) production. The crude enzyme was used to decolorize the dyes. The degradation rates of acid yellow, bromo-chloroform purple, and reactive black 5 were >82%.

Peels from Citrus sinensis and C. limon were used for the preparation of essential oils. The hydrodistilled citrus peels presented various compounds, including cyclohexene, 1-methyl-4-(1-methylethenyl)-, (S)- (91.8%) and 7-methyl-3-methylene-1,6-octadiene(3.40%). Compared with the essential oils isolated from C. limon, the C. sinensis essential oil showed maximum radical scavenging activity, with an IC50 value of 4.31 µg/mL. Bacillus subtilis growth was generally inhibited by essential oils, and the zone of inhibition was 21 ± 1 mm, while the zone of inhibition was 20 ± 2 mm against Escherichia coli. The minimum inhibitory concentration ranged from 12 ± 1 to 128 ± 2.6 µg/mL. Similarly, essential oils presented lower minimum bactericidal concentrations against Bacillus subtilis, followed by Escherichia coli. The antimicrobial activity was tested using packed samples of fresh-cut guava fruit stored under refrigeration. The essential oil-treated guava fruit presented a decreased viable cell count. After 2 days of C. sinensis and C. limon essential oil treatment, the reduction in B. subtilis was approximately 1.7 log CFU/g compared with that of the control. In cut fruits treated with L. monocytogenes, the essential oils significantly reduced the bacterial population, and a 7 log CFU/g reduction was achieved after 8 days of treatment (p<0.05).

Diabetes Mellitus is a metabolic disease that leads to microvascular complications like Diabetic retinopathy (DR), a major cause of blindness worldwide. Current medications for DR are expensive and report multiple side effects; therefore, an alternative medication that alleviates the disease condition is required. An interventional approach targeting the vascular endothelial growth factor (VEGF) remains a treatment strategy for DR. Anti-VEGF medicines are being investigated as the main therapy for managing vision-threatening complications of DR, such as diabetic macular oedema. Therefore, this study investigated the effect of flavonoid naringenin (NG) from citrus fruits on inhibiting early DR in zebrafish. When exposed to 130 mM glucose, the zebrafish larvae developed a hyperglycaemic condition accompanied by oxidative stress, cellular damage, and lipid peroxidation. Similarly, when adult zebrafish were exposed to 4% Glucose, high glucose levels were observed in the ocular region and massive destruction in the retinal membrane. High glucose upregulated the expression of VEGF. In comparison, the co-exposure to NG inhibited oxidative stress and cellular damage and restored the glutathione levels in the ocular region of the zebrafish larvae. NG regressed the glucose levels and cellular damage along with an inhibition of macular degeneration in the retina of adult zebrafish and normalized the overexpression of VEGF as a promising strategy for treating DR. Therefore, intervention of NG could alleviate the domestication of alternative medicine in ophthalmic research.

Numerous conventional methods are available for analyzing various water quality parameters to determine the water quality index. However, ongoing surveillance is necessary for large bodies of water. A water quality monitoring system supports a robust surface and groundwater ecosystem. Various tactics are used to improve aquatic habitats: identification of the precise chemical pollutants released into the aquatic environment; advancements in assessing ecological effects; and working on ways to enhance water quality through informing the public, communities, businesses, etc. In order to save the marine ecosystem and those who entirely depend on these enormous bodies of water, it is also crucial to continuously handle many data sets of water quality metrics. To predict the water quality index, this review paper provides an overview of water quality monitoring, the modeling and numerous sensors employed, and various artificial intelligence approaches. Various water quality models were proposed to assess pH, a few components, and alkalinity. Additionally, handling raw information for surface and groundwater quality metrics was studied using artificial intelligence techniques like neural networks.