Patterns and determinants of the global herbivorous mycobiome.

Despite their role in host nutrition, the anaerobic gut fungal (AGF) component of the herbivorous gut microbiome remains poorly characterized. Here, to examine global patterns and determinants of AGF diversity, we generate and analyze an amplicon dataset from 661 fecal samples from 34 mammalian species, 9 families, and 6 continents. We identify 56 novel genera, greatly expanding AGF diversity beyond current estimates (31 genera and candidate genera). Community structure analysis indicates that host phylogenetic affiliation, not domestication status and biogeography, shapes the community rather than. Fungal-host associations are stronger and more specific in hindgut fermenters than in foregut fermenters. Transcriptomics-enabled phylogenomic and molecular clock analyses of 52 strains from 14 genera indicate that most genera with preferences for hindgut hosts evolved earlier (44-58 Mya) than those with preferences for foregut hosts (22-32 Mya). Our results greatly expand the documented scope of AGF diversity and provide an ecologically and evolutionary-grounded model to explain the observed patterns of AGF diversity in extant animal hosts.

Effect of altitude and solvent on Psidium guajava Linn. leaves extracts: phytochemical analysis, antioxidant, cytotoxicity and antimicrobial activity against food spoilage microbes.

BACKGROUND: Guava (Psidium guajava Linn.) has been traditionally used in the treatment of a wide range of diseases due to its rich content of secondary metabolites. AIM: This study was aimed to evaluate the effect of altitude and solvent systems on guava leaves crude extract's phenolics and flavonoid content, antioxidant, antimicrobial, and toxicity nature. METHODS: Guava leaves were collected from three different geographical locations in Nepal while solvents with an increasing polarity index were used for extraction. The yield percentage of extracts was calculated. Total Phenolic Content, Total Flavonoid Content, and antioxidant activity were determined by the Folin-Ciocalteu method, Aluminium chloride colorimetric method, and DPPH (2,2'-Diphenyl-1-picrylhydrazyl) assay respectively. The quantification of fisetin and quercetin was performed using the HPLC with method validation. The antimicrobial activity of the extracts was tested against bacteria and fungus isolated from spoiled fruits and vegetables and identified through 16s and 18s rRNA sequencing. Finally, Brine Shrimp Lethality Assay (BSLA) was used for testing the toxicity of the extracts. RESULTS: The phenolic and total flavonoid content was found to be higher in ethanol extract (331.84 mg GAE/g dry extract) and methanol extract (95.53 mg QE/g dry extract) from Kuleshwor respectively. Water extract of guava leaves from Kuleshwor (WGK) did not show significantly different antioxidant activity when compared to methanol and ethanol extracts. Fisetin and quercetin were higher in WGK (1.176 mg/100 g) and (10.967 mg/100 g) dry extract weight respectively. Antibacterial activity against food spoilage bacteria was dose-dependent and found to be highest for all the extracts from different solvents and altitudes at higher concentrations (80 mg/ml). Similarly, methanol and ethanol guava extracts from all locations showed antifungal activity against Geotrichum candidum RIBB-SCM43 and Geotrichum candidum RIBB-SCM44. WGK was found to be non-toxic. CONCLUSION: Our study concludes that the antioxidant and antimicrobial activity of WGK was found to be similar statistically to that of methanol and ethanol extracts of Bishnupur Katti and Mahajidiya. These results suggest the possibility of using water as a sustainable solvent to extract natural antioxidant and antimicrobial compounds which can further be used as natural preservatives to extend the shelf life of fruits and vegetables.

Maculosin, a non-toxic antioxidant compound isolated from Streptomyces sp. KTM18.

CONTEXT: Streptomyces species are prolific sources of bioactive secondary metabolites known especially for their antimicrobial and anticancer activities. OBJECTIVE: This study sought to isolate and characterize antioxidant molecules biosynthesized by Streptomyces sp. KTM18. The antioxidant potential of an isolated compound and its toxicity were accessed. MATERIALS AND METHODS: The compound was purified using bioassay-guided chromatography techniques. Nuclear magnetic resonance (NMR) experiments were carried out for structure elucidation. The antioxidant potential of the isolated compound was determined using DPPH free radical scavenging assay. The toxicity of the isolated compound was measured using a brine shrimp lethality (BSL) assay. RESULTS: Ethyl acetate extract of Streptomyces sp. KTM18 showed more than 90% inhibition of DPPH free radical at 50 µg/mL of the test concentration. These data were the strongest among 13 Streptomyces isolates (KTM12-KTM24). The active molecule was isolated and characterized as maculosin (molecular formula, C14H16N2O3 as determined by the [M + H]+ peak at 261.1259). The DPPH free radical scavenging activity of pure maculosin was higher (IC50, 2.16 ± 0.05 µg/mL) than that of commercial butylated hydroxyanisole (BHA) (IC50, 4.8 ± 0.05 µg/mL). No toxicity was observed for maculosin (LD50, <128 µg/mL) in brine shrimp lethality assay (BSLA) up to the compound's antioxidant activity (IC50) concentration range. The commercial standard, berberine chloride, showed toxicity in BSLA with an LD50 value of 8.63 ± 0.15 µg/mL. CONCLUSIONS: Maculosin may be a leading drug candidate in various cosmetic and therapeutic applications owing to its strong antioxidant and non-toxic properties.

Draft Genome Sequence of the Sattazolin-Producing Strain Pseudonocardia sp. C8, Isolated from a Mud Dauber Wasp Nest in Nepal.

Here, we report a 6.2-Mbp draft genome sequence of the bacterium Pseudonocardia sp. strain C8, which gave insight into the complete secondary metabolite production capacity of the strain and hinted that the strain possibly represents a new species.

Draft Genome Sequence of Nonomuraea sp. Strain C10, a Producer of Brartemicin, Isolated from a Mud Dauber Wasp Nest in Nepal.

Nonomuraea sp. strain C10 produces the cytotoxic natural product brartemicin. Here, we report its draft genome sequence to get insight into brartemicin biosynthesis and to enable genome mining for novel secondary metabolites.