In this study, we investigated the diversity of fungal endophytes associated with Pinus wallichiana from the Western Himalayas, with emphasis on comparison of endophytic communities harbored by the stem and needle tissues of the host and their antimicrobial potential. A total number of 130 isolates, comprising of 38 different genera, were recovered from 210 fragments of the plant. Among the isolated fungi, only a single isolate, Tritirachium oryzae, belonged to the Phylum Basidiomycota whereas the rest belonged to Ascomycota. Dothideomycetes was the dominant class with the highest isolation frequency of 49.2 %. The most frequent colonizers of the host were Alternaria spp., Pestalotiopsis spp., Preussia spp., and Sclerostagonospora spp. The diversity and species richness were higher in needle tissues than in the stems. Antimicrobial activities were displayed by extracts from a total number of 22 endophytes against one or more pathogens. Endophytes designated as P1N13 (Coniothyrium carteri), P2N8 (Thielavia subthermophila), P4S6b (Truncatella betulae), P7N10 (Cochliobolus australiensis), and P8S4 (Tritirachium oryzae) were highly active against Candida albicans. Broad spectrum antimicrobial activities were obtained with the extracts of P8-S4 (Tritirachium oryzae) and P5-N26 (Coniochaeta gigantospora) that were potentially active against the Gram-positive and Gram-negative bacteria as well as the fungal pathogen, Candida albicans. The most prominent antagonistic activity against fungal pathogens was shown by P8-S4 (Tritirachium oryzae), P5-N31a (Truncatella spadicea), and P5-N20 (Fusarium larvarum). Our findings indicate that Pinus wallichiana harbors a rich endophytic fungal community with potential antimicrobial activities. Further studies are needed to understand the ecology and evolutionary context of the associations between the Himalayan pine and its endophytes.
Influenza virus surface glycoprotein hemagglutinin (HA) is an excellent and chief target that elicits neutralizing antibodies during vaccination or natural infection. Its HA2 subunit (stem domain) is most conserved as compared to HA1 subunit (globular head domain). Current influenza vaccine relies on globular head domain that provides protection only against the homologous vaccine strains, rarely provides cross-protection against divergent strains, and needs to be updated annually. There is an urge for a truly universal vaccine that provides broad cross-protection against different subtype influenza A viruses along with influenza B viruses and need not be updated annually. Antibodies against the stem domain of hemagglutinin (HA) are able to neutralize a wide spectrum of influenza virus strains and subtypes. These stem-specific antibodies have great potential for the development of universal vaccine against influenza viruses. In this review, we have discussed the stem-specific cross-reactive antibodies and heterosubtypic protection provided by them. We have also discussed their epitope-based DNA vaccine and their future prospects in this scenario.
The COVID-19 pandemic has caused huge socio-economic losses and continues to threat humans worldwide. With more than 4.5 million deaths and more than 221 million confirmed COVID-19 cases, the impact on physical, mental, social and economic resources is immeasurable. During any novel disease outbreak, one of the primary requirements for effective mitigation is the knowledge of clinical manifestations of the disease. However, in absence of any unique identifying characteristics, diagnosis/prognosis becomes difficult. It intensifies misperception and leads to delay in containment of disease spread. Numerous clinical research studies, systematic reviews and meta-analyses have generated considerable data on the same. However, identification of some of the distinct clinical signs and symptoms, disease progression biomarkers and the risk factors leading to adverse COVID-19 outcomes warrant in-depth understanding. In view of this, we assessed 20 systematic reviews and meta-analyses with an intent to understand some of the potential independent predictors/biomarkers/risk factors of COVID-19 severity and mortality.
The 2009 influenza pandemic A(H1N1)pdm09 of swine origin and the continued circulation of highly pathogenic avian H5N1 strain in humans are stark reminders of the unpredictable nature of the influenza virus. Experiences from the 1918 and 20th century influenza pandemics helped immensely in the preparation of a better response for A(H1N1)pdm09. The explosive pattern of the 1918 pandemic makes it a benchmark for pandemic planning and preparedness today. Its similarities with the 2009 pandemic makes it even more intriguing, and it is a great surprise that the two strains, separated by a period of 91 years, share such similar features. This review is an attempt to summarize the literature describing the important features of the 1918 and 2009 pandemics. This may provide a better understanding for the early detection and control of influenza pandemics in the future.
Nonstructural protein 1 (NS1) of influenza A viruses counteracts the host immune response against the influenza viruses by not only inhibiting the nuclear export and maturation of host cell messenger RNA (mRNA), but by also blocking the double-stranded RNA-activated protein kinase-mediated inhibition of viral RNA translation. Reduction of NS1 gene product in the host cell may be a potent antiviral strategy to provide protection against the influenza virus infection. We used small interfering RNAs (siRNAs) synthesized against the viral mRNA to down regulate the NS1 gene and observed its effect on inhibition of virus replication. When NS1 gene-specific siRNA were transfected in Madin Darby canine kidney (MDCK) cells followed by influenza A virus infection, approximately 60% inhibition in intracellular levels of NS1 RNA was observed. When siRNA was administered in BALB/c mice, 92% reduction in the levels of NS1 gene expression in mice lungs was observed. A significant reduction in the lung virus titers and cytokine levels was also detected in the presence of siRNAs as compared with the untreated control. The study was validated by the use of selectively disabled mutants of each set of siRNA. Our findings suggest that siRNA targeted against NS1 gene of influenza A virus can provide considerable protection to the virus-infected host cells and may be used as potential candidates for nucleic acid-based antiviral therapy for prevention of influenza A virus infection.
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