Natural Products and Antiviral Resistance

Viral diseases are minacious with the potential for causing pandemics and treatment is complicated because of their inherent ability to mutate and become resistant to drugs. Antiviral drug resistance is a persistent problem that needs continuous attention by scientists, medical professionals, and government agencies. To solve the problem, an in-depth understanding of the intricate interplay between causes of antiviral drug resistance and potential new drugs specifically natural products is imperative in the interest and safety of public health. This review delves into natural product as reservoir for antiviral agents with the peculiar potentials for addressing the complexities associated with multi-drug resistant and emerging viral strains. An evaluation of the mechanisms underlying antiviral drug activity, antiviral drug resistance is addressed, with emphasis on production of broad-spectrum antiviral agents from natural sources. There is a need for continued natural product-based research, identification of new species and novel compounds.

A New Species of the Genus Tylototriton(Amphibia: Urodela: Salamandridae) from Eastern Himalaya

A new species of the genus Tylototriton is described from eastern Himalaya based on molecular and morphological comparisons. The new species is diagnosable from the closely-related species by having light brown colouration in dorsal region in life, flat and blunt snout, greatly separated dorsolateral bony ridges on head and straightthick tailfin. In addition to head morphology, the new species is also morphologically distinguishable from its closelyrelated species Tylototriton shanorum by having 16 dorsal warts and average smaller Snout Vent Length（SVL）.

Description of a New Species of Amolops Cope, 1865(Amphibia: Ranidae) from Nepal and Nomenclatural Validation of Amolops nepalicus Yang, 1991

A new species,Amolops mahabharatensis sp.nov.,is described from Mahabharat range(middle mountain)of Nepal.The new species is a member of the A.marmoratus group and is distinguished from its congeners using morphological and molecular data.The new species is diagnosed by having numerous warts on dorsum and flanks,dorsal body greyish olivebrown/light brown,presence of vomerine teeth series,presence of a pair of subgular vocal sacs in males and tadpole withⅢ:5+5/1+1:Ⅱ–labial tooth row.In addition,evidenced by the phylogenetic and morphological analyses in this study,Amolops nepalicus is shown to be a valid species.A molecular phylogenetic analysis based on 16 S ribosomal gene for six members of the A.marmoratus group suggested that the new species is sister to a clade containing A.nepalicus and A.panhai.The uncorrected genetic divergences between the new species and its closest congeners A.nepalicus,A.panhai and A.marmoratus based on 16 S rRNA gene were 10.5%,11.6%,and 8.6%respectively.The new species showed wide distribution in the Mahabharat range of Nepal.

A New Species of Megophryid Frog of the Genus Scutiger from Kangchenjunga Conservation Area, Eastern Nepal

This study investigated the systematics of the megophryid genus Scutiger from eastern and western Nepal using molecular and morphological data. Our results support two divergent lineages, one of which has nuptial spines on the dorsal surface of the first three fingers while the other has spines only on the dorsal surface of the first two fingers. The Ghunsa lineage from eastern Nepal shows significant morphological and molecular differences to other species of genus Scutiger and is here described as a new species. Based on the molecular analysis, the Muktinath lineage from western Nepal is confirmed to be Scutiger boulengeri and represents a species complex widespread throughout the Himalayan region. The newly described taxon is endemic to the eastern Himalayas and currently known only from the Ghunsa valley, Taplejung district, Nepal.

A Complete Embryonic Developmental Table of Microhyla fissipes(Amphibia,Anura,Microhylidae)

Access to embryonic developmental stages is essential basic work for understanding how organisms develop. In this study, seven egg clutches（range 209–564 eggs） of ornamented pygmy frog Microhyla fissipes（Amphibia, Anura, Microhylidae） were obtained from seven breeding pairs in laboratory. One egg clutch of them was observed for the embryonic development, and the staging table of normal development was constructed based on morphological and physiological characteristics. Forty-five developmental stages were defined for M. fissipes, and two major developmental periods were designated： 1） early embryonic development period（stages 1–28）, from fertilization to operculum completion stage, lasted for 82.6 hours at water temperature（WT） 23–25℃; 2） larval development period（stages 29–45）, from operculum completion to tail complete absorption stage, took 38 days at WT 22–26.5℃, showing that the embryos of this species develop rapidly. In addition, the tadpoles were transparent, which is similar to those in field. These characteristics suggest that M. fissipes would be a good model to study developmental biology, adaptive mechanisms from aquatic to terrestrial phases, environmental toxicology, and human disease.

An Integrative Taxonomy of Amphibians of Nepal:An Updated Status and Distribution

Amphibians are declining worldwide.At the same time,each year many species of amphibians are described,indicating that biological diversity on Earth remains poorly understood.This is especially true for mountainous regions,such as the Himalayas,which are also regarded as a biodiversity hotspot.However,it is most likely that the current diversity of amphibians in Nepal is highly underestimated.Amphibian inventories by the past researchers primarily used phenotypic characters as the basis for species identification.However,the application of molecular systematics methods to taxonomic studies has successfully uncovered the taxonomic status of several cryptic taxa.This study used both molecular(16 S rDNA sequences)and morphological comparisons and estimated the diversity of amphibians from Nepal.This study reports the occurrence of 38 species of amphibians based on both molecular and morphological comparisons.Among them,three species were recorded for the first time in Nepal.This study also invalids the taxonomic status of Sphaerotheca paschima.This study highlights the importa nce of integrative taxonomic approaches that help to resolve the current taxonomic ambiguities of Nepalese amphibians.

Characterization of glucose isomerase-producing bacteria and optimization of fermentation conditions for producing glucose isomerase using biomass

Glucose isomerase(GI)is an enzyme with high potential applications.Characterization of GI producing bacteria with interesting properties from an industrial point of view is essential.Bacillus sp.,Paenarthrobacter sp.,Chryseobacterium sp.,Hymenobacter sp.,Mycobacterium sp.,and Stenotrophomonas sp.were isolated from soil samples.Optimization of enzyme production yield was investigated in various fermentation conditions using response surface methodology.All isolates exhibited maximum GI activity at 40℃,pH 6–8 after 4 days of incubation.A mixture of peptone/yeast extract or tryptone/peptone enhanced higher enzyme production.The same trend was observed in fermentation medium containing 1%xylose or 2%–2.5%wheat straw.This study advanced the knowledge of these bacterial isolates in promoting wheat straw as feedstock for the bio-based industry.