Estradiol-17beta-hydroxysteroid dehydrogenase activity in preimplantation rat embryos

In previous studies (1–3), we have shown that Δ⁵ -3β-hydroxysteroid dehydrogenase (3β-HSD) activity in rat embryos begins on Day 4 of pregnancy (Day 1 = day of finding spermatozoa in the vagina), it peaks on Day 5, and sharply declines on Day 6. The present study investigated the presence of estradiol-17β-hydroxysteroid dehydrogenase (17β-HSD) in rat embryos recovered on Days 4, 5 and 6. The pattern of the 17β-HSD activity was similar to that of 3β-HSD. Thus, the present results strengthen our previous contention that rat morulae and blastocysts synthesize steroid hormones; moreover, the results suggest that one of the hormones synthesized is estrogen.     

Structural Insights into the Induced-fit Inhibition of Fascin by a Small-Molecule Inhibitor

Tumor metastasis is responsible for ~ 90% of all cancer deaths. One of the key steps of tumor metastasis is tumor cell migration and invasion. Filopodia are cell surface extensions that are critical for tumor cell migration. Fascin protein is the main actin-bundling protein in filopodia. Small-molecule fascin inhibitors block tumor cell migration, invasion, and metastasis. Here we present the structural basis for the mechanism of action of these small-molecule fascin inhibitors. X-ray crystal structural analysis of a complex of fascin and a fascin inhibitor shows that binding of the fascin inhibitor to the hydrophobic cleft between the domains 1 and 2 of fascin induces a ~ 35^o rotation of domain 1, leading to the distortion of both the actin-binding sites 1 and 2 on fascin. Furthermore, the crystal structures of an inhibitor alone indicate that the conformations of the small-molecule inhibitors are dynamic. Mutations of the inhibitor-interacting residues decrease the sensitivity of fascin to the inhibitors. Our studies provide structural insights into the molecular mechanism of fascin protein function as well as the action of small-molecule fascin inhibitors.     

Kuepferia kanchii sp. nov. (Gentianaceae) from Sikkim Himalaya

Kuepferia kanchii D. Maity, Sentu K. Dey & Adr. Favre, a new species from Sikkim Himalaya, is described and illustrated. It differs from its close relative K. infelix (C. B. Clarke) Adr. Favre ( = Gentiana infelix C. B. Clarke) by having sessile and smaller flowers, and smaller floral parts. Kuepferia kanchii is further characterized by a white corolla with bluish green patches on the outside at the base of each corolla lobe, and a corolla tube flushed with light green inside towards the base, blue filaments, sessile stigma, smaller capsule, and trigonous–elongated, ca 0.8 mm long and curved seeds.     

Comparison among four triazole fungicides on growth and development of sheath blight of rice pathogen Rhizoctonia solani Kühn AG1-1A

The sheath blight of rice pathogen Rhizoctonia solani Kühn AG1-1A has long been known as a major crisis in global rice production. The present study aimed to compare the efficacy of four triazole fungicides at different doses on the growth and development of R. solani Kühn AG1-1A. Obtained results demonstrated inhibitory effects of all four fungicides on mycelial growth, sclerotia formation and biomass production of R. solani Kühn AG1-1A with significant variation among the treatment doses as well as fungicide molecules (p ≤ 0.05). At the respective EC₅₀ doses all four fungicides inhibited cell wall degrading enzymes viz. invertase, cellulase, polygalacturonase and pectin lyase, of the sheath blight pathogen. The extent of inhibition of the enzymes significantly varied among the fungicides. It is important to note that in spite of having common mode of action, all four triazole fungicides demonstrated significant variation in their fungicidal efficacy on R. solani Kühn AG1-1A.     

Eliminating accidental deviations to minimize generalization error and maximize replicability: Applications in connectomics and genomics

Replicability, the ability to replicate scientific findings, is a prerequisite for scientific discovery and clinical utility. Troublingly, we are in the midst of a replicability crisis. A key to replicability is that multiple measurements of the same item (e.g., experimental sample or clinical participant) under fixed experimental constraints are relatively similar to one another. Thus, statistics that quantify the relative contributions of accidental deviations—such as measurement error—as compared to systematic deviations—such as individual differences—are critical. We demonstrate that existing replicability statistics, such as intra-class correlation coefficient and fingerprinting, fail to adequately differentiate between accidental and systematic deviations in very simple settings. We therefore propose a novel statistic, discriminability, which quantifies the degree to which an individual’s samples are relatively similar to one another, without restricting the data to be univariate, Gaussian, or even Euclidean. Using this statistic, we introduce the possibility of optimizing experimental design via increasing discriminability and prove that optimizing discriminability improves performance bounds in subsequent inference tasks. In extensive simulated and real datasets (focusing on brain imaging and demonstrating on genomics), only optimizing data discriminability improves performance on all subsequent inference tasks for each dataset. We therefore suggest that designing experiments and analyses to optimize discriminability may be a crucial step in solving the replicability crisis, and more generally, mitigating accidental measurement error.     

Expression of Multiple Virus-derived Resistance Determinants in Transgenic Plants Does Not Lead to Additive Resistance Properties

Plants can be protected against infection by potyviruses by expressing different portions of potyviral genomes as transgenes. This strategy has proven effective with several potyvirus genes, including the Nla, Nlb, and coat protein coding regions. Given the effectiveness of separate potyvirus coding regions as determinants of resistance, we tested the hypothesis that combinations of potyvirus coding regions would provide additively greater protection of plants against potyviruses. For this, we compared transgenic plant lines that expressed either the coat protein (CP) or the Nla+Nlb+coat protein (NNC) coding regions from tobacco vein mottling virus (TVMV). We found that plants that carry the NNC gene combination were invariably less resistant to TVMV than were lines that contain a CP gene alone. Additionally, we found that NNC lines displayed virtually no resistance to tobacco etch virus (TEV), in contrast to the CP lines. We conclude that combining more than one virus-derived resistance determinant in a single construct is detrimental to the production of virus-resistant plants.     

Variation at 4 short tandem repeat loci in 8 population groups of India.

We have determined the nature and extent of variation at 4 STR loci (CSF1P0, TPOX, TH01, VWA) in 8 caste and tribal population groups of eastern and northern India. Large differences in allele frequencies among the groups were found. Average heterozygosities in all populations were high (approximately 80%). The overall extent of gene differentiation among the 8 groups was high (GST = 0.04). The nature of genomic affinities based on these 4 STR loci does not completely agree with our earlier finding based on classical genetic markers that geographic proximity of habitat has a greater influence on genetic similarity between populations than sociocultural proximity does.