A new class of 5-HT2B antagonists possesses favorable potency,selectivity, and rat pharmacokinetic properties

We have been exploring the potential of 5-HT_2B antagonists as a therapy for chronic heart failure. To assess the potential of this therapeutic approach, we sought compounds possessing the following attributes: (a) potent and selective antagonism of the 5-HT_2B receptor, (b) low impact of serum proteins on potency, and (c) desirable pharmacokinetic properties. This Letter describes our investigation of a biphenyl benzimidazole class of compounds that resulted in 5-HT_2B antagonists possessing the above attributes. Improving potency in a human serum albumin shift assay proved to be the most significant SAR discovery.     

Mitochondrial degeneration and not apoptosis is the primary cause of embryonic lethality in ceramide transfer protein mutant mice

Ceramide transfer protein (CERT) functions in the transfer of ceramide from the endoplasmic reticulum (ER) to the Golgi. In this study, we show that CERT is an essential gene for mouse development and embryonic survival and, quite strikingly, is critical for mitochondrial integrity. CERT mutant embryos accumulate ceramide in the ER but also mislocalize ceramide to the mitochondria, compromising their function. Cells in mutant embryos show abnormal dilation of the ER and degenerating mitochondria. These subcellular changes manifest as heart defects and cause severely compromised cardiac function and embryonic death around embryonic day 11.5. In spite of ceramide accumulation, CERT mutant mice do not die as a result of enhanced apoptosis. Instead, cell proliferation is impaired, and expression levels of cell cycle–associated proteins are altered. Individual cells survive, perhaps because cell survival mechanisms are activated. Thus, global compromise of ER and mitochondrial integrity caused by ceramide accumulation in CERT mutant mice primarily affects organogenesis rather than causing cell death via apoptotic pathways.     

Identification of quantitative trait loci for agronomically important traits and their association with genic-microsatellite markers in sorghum

The identification of quantitative trait loci (QTLs) affecting agronomically important traits enable to understand their underlying genetic mechanisms and genetic basis of their complex interactions. The aim of the present study was to detect QTLs for 12 agronomic traits related to staygreen, plant early development, grain yield and its components, and some growth characters by analyzing replicated phenotypic datasets from three crop seasons, using the population of 168 F₇ RILs of the cross 296B × IS18551. In addition, we report mapping of a subset of genic-microsatellite markers. A linkage map was constructed with 152 marker loci comprising 149 microsatellites (100 genomic- and 49 genic-microsatellites) and three morphological markers. QTL analysis was performed by using MQM approach. Forty-nine QTLs were detected, across environments or in individual environments, with 1–9 QTLs for each trait. Individual QTL accounted for 5.2–50.4% of phenotypic variance. Several genomic regions affected multiple traits, suggesting the phenomenon of pleiotropy or tight linkage. Stable QTLs were identified for studied traits across different environments, and genetic backgrounds by comparing the QTLs in the study with previously reported QTLs in sorghum. Of the 49 mapped genic-markers, 18 were detected associating either closely or exactly as the QTL positions of agronomic traits. EST marker Dsenhsbm19, coding for a key regulator (EIL-1) of ethylene biosynthesis, was identified co-located with the QTLs for plant early development and staygreen trait, a probable candidate gene for these traits. Similarly, such exact co-locations between EST markers and QTLs were observed in four other instances. Collectively, the QTLs/markers identified in the study are likely candidates for improving the sorghum performance through MAS and map-based gene isolations.     

Fusobacterium necrophorum: a ruminal bacterium that invades liver to cause abscesses in cattle

Fusobacterium necrophorum, a Gram-negative, rod-shaped, and an aerotolerant anaerobe, is a normal inhabitant of the rumen of cattle. The organism is in ruminal contents and adherent to the ruminal wall. Its role in ruminal fermentation is to metabolize lactic acid and degrade feed and epithelial proteins. The ruminal concentration is higher in grain-fed than forage-fed cattle. From the rumen, the organism gains entry into the portal circulation and is trapped in the liver to cause abscesses. The organism is an opportunistic pathogen and a primary causative agent of liver abscesses, an economically important disease of grain-fed cattle. Liver abscesses are often secondary to ruminal acidosis and rumenitis in grain-fed cattle. Two subspecies of F. necrophorum, subsp. necrophorum (biotype A) and subsp. funduliforme (biotype B), are recognized that can be differentiated based on morphological, biochemical, biological and molecular characteristics. The subsp. necrophorum is more virulent and is isolated more frequently from infections than the subsp. funduliforme. Several toxins or secreted products have been implicated as virulence factors. The major factors contributing to ruminal colonization and invasion into the liver are hemagglutinin, endotoxin and leukotoxin, of which leukotoxin is the protective antigen. In some conditions, the organism synergistically interacts with Arcanobacterium pyogenes, a facultative anaerobic organism and a secondary etiologic agent, to cause liver abscesses.     

A systematic review and meta-analysis on the prevalence of infectious diseases of Duck: A world perspective

The Indian poultry industry is one of the fast-growing sectors of which duck farming plays an important role. Duck population in India is 33.51 million that is concentrated towards north-east and southern parts of the country who rears mainly for eggs and meat. Duck diseases are of great concern as they badly affect the financial status of the small, landless farmers. Databases such as Google Scholar, PubMed, J gate were used to search articles between 2000 and 2019 that showed the prevalence of viral, bacterial, and parasitic duck diseases. R open source software was used to derive forest plots by statistical analysis. Pooled prevalence estimates of duck diseases worldwide was found to be 20% (95%-CI:15–26). Also, continent-wise analysis of all duck diseases has revealed highest prevalence in North America, followed by Asia, Africa, Europe,Oceania and South America. This prevalence of data would be helpful to the policymakers to develop appropriate intervention strategies to prevent and control diseases in their respective locations.     

Association of the functional KL-VS variant of Klotho gene with early-onset ischemic stroke

Genetic variants of Klotho have been reported to be associated with human longevity and atherosclerotic vascular events and risk factors. However, very few studies have explored their association with ischemic stroke. We hypothesized that the functional KL-VS and the exonic C1818T variants of Klotho gene may be associated with ischemic stroke in Indian population. We enrolled a total of 460 patients with ischemic stroke and 574 age- and gender-matched controls for the study. Genotyping was done by polymerase chain reaction and restriction fragment length polymorphism. Contrary to other Asian reports, KL-VS variant was polymorphic in our population, with a frequency distribution similar to that of Caucasians. The frequency distribution of the C1818T variant was similar to previously reports in Asians. A differential effect of age on association of Klotho KL-VS variant with ischemic stroke was observed. In subjects aged ≤40 years, the KL-VS homozygotes, 352FF and 352VV, had ~1.5-fold (OR=1.57; 95% CI: 1.02-2.40, p=0.038) and ~3-fold (OR=3.29; 95%CI: 1.02-10.56, p=0.046) higher risk of stroke compared to heterozygotes, whereas in the older group (aged >40 years) no significant association was observed. The C1818T variant was not associated with ischemic stroke. We conclude that KL-VS homozygosity could contribute to early-onset stroke in India. Larger studies in other ethnic populations are warranted to determine the role of these gene variants in the etiology of stroke occurring in the young.     

Importance of AOX pathway in optimizing photosynthesis under high light stress: role of pyruvate and malate in activating AOX

The present study shows the importance of alternative oxidase (AOX) pathway in optimizing photosynthesis under high light (HL). The responses of photosynthesis and respiration were monitored as O₂ evolution and O₂ uptake in mesophyll protoplasts of pea pre‐incubated under different light intensities. Under HL (3000 µmol m^?2 s^?1), mesophyll protoplasts showed remarkable decrease in the rates of NaHCO₃‐dependent O₂ evolution (indicator of photosynthetic carbon assimilation), while decrease in the rates of respiratory O₂ uptake were marginal. While the capacity of AOX pathway increased significantly by two fold under HL, the capacity of cytochrome oxidase (COX) pathway decreased by >50% compared with capacities under darkness and normal light (NL). Further, the total cellular levels of pyruvate and malate, which are assimilatory products of active photosynthesis and stimulators of AOX activity, were increased remarkably parallel to the increase in AOX protein under HL. Upon restriction of AOX pathway using salicylhydroxamic acid (SHAM), the observed decrease in NaHCO₃‐dependent O₂ evolution or p‐benzoquinone (BQ)‐dependent O₂ evolution [indicator of photosystem II (PSII) activity] and the increase in total cellular levels of pyruvate and malate were further aggravated/promoted under HL. The significance of raised malate and pyruvate levels in activation of AOX protein/AOX pathway, which in turn play an important role in dissipating excess chloroplastic reducing equivalents and sustenance of photosynthetic carbon assimilation to balance the effects of HL stress on photosynthesis, was depicted as a model.     

A multiplex PCR procedure for the detection of six major virulence genes in Escherichia coli O157:H7

A multiplex PCR procedure that detects six major virulence genes, fliC, stx1, stx2, eae, rfbE, and hlyA, in Escherichia coli O157:H7 was developed. Analyses of the available sequences of the six major virulence genes and the published primers allowed us to develop the six-gene, multiplex PCR protocol that maintained the specificity of each primer pair. The resulting six bands for fliC, stx1, stx2, eae, rfbE, and hlyA were even and distinct with product sizes of 949, 655, 477, 375, 296, and 199 bp, respectively. The procedure was validated with a total of 221 E. coli strains that included 4 ATCC, 84 cattle, and 57 human E. coli O157:H7 strains as well as 76 non-O157 cattle and human E. coli strains. The results of all 221 strains were similar to the results generated by established multiplex PCR methods that involved two separate reactions to detect five virulence genes (stx1, stx2, eae, fliC, and hlyA). Specificity of the O antigen was indicated by amplification of only O157, and not O25, O26, O55, O78, O103, O111, O127, and O145 E. coli serotypes. Sensitivity tests showed that the procedure amplified genes from a fecal sample spiked with a minimum of 10⁴ CFU/g (10 cells/reaction) of E. coli O157. After a 6-h enrichment of E. coli O157-spiked samples, a sensitivity level of 10 CFU/g was achieved.