Fine structural description of the compound eye of the Madagascar 'hissing cockroach'Gromphadorhina portentosa (Dictyoptera: Blaberidae)

The compound eyes of the wingless adults of the Madagascar ‘hissing cockroach’Gromphadorhina portentosa Sachum, 1853 were examined by light and electron microscopy. Each eye contains 2 400‐2 500 mostly hexagonal facets. However, irregularities affecting both shape and size of the ommatidia are relatively common, especially towards the margins of the eye. An individual ommatidium of this eucone type of apposition eye contains eight retinula cells, which give rise to a centrally‐fused, tiered rhabdom. The distal end of the latter is funnel‐shaped and accommodates the proximal end of the cone in its midst. Further below, the rhabdom (then formed by the rhabdomeres of four retinula cells) assumes a squarish profile with microvilli aligned in two directions at right‐angle to each other. Cross sections through the proximal regions of the rhabdom display triangular rhabdom outlines and microvilli (belonging to 3‐4 retinula cells different from those involved in the squarish more distal rhabdom) that run in three directions inclined to one another by 120°. Overall the organization of the eye conforms to the orthopteroid pattern and particularly closely resembles that of the American cockroach Periplaneta americana. However, since G. portentosa possesses fewer ommatidia, this could be a consequence of its inability to fly. On the other hand, the large size of the facets and the voluminous rhabdoms suggest considerable absolute sensitivity and an ability to detect the plane of linearly polarized light. Based on the pattern of microvillus orientations in combination with the crepuscular lifestyle G. portentosa leads and the habitat it occurs in, the prediction is made that this insect uses its green receptors for e‐vector discrimination in the environment of down‐welling light that reaches the forest floor.     

GyrI: a counter-defensive strategy against proteinaceous inhibitors of DNA gyrase

DNA gyrase is the target of two plasmid-encoded toxins CcdB and microcin B17, which ensure plasmid maintenance. These proteins stabilize gyrase–DNA covalent complexes leading to double-strand breaks in the genome. In contrast, the physiological role of chromosomally encoded inhibitor of DNA gyrase (GyrI) in Escherichia coli is unclear and its mechanism of inhibition has not been established. We demonstrate that the mode of inhibition of GyrI is distinct from all other gyrase inhibitors. It inhibits DNA gyrase prior to, or at the step of, binding of DNA by the enzyme. GyrI reduces intrinsic as well as toxin-stabilized gyrase–DNA covalent complexes. Furthermore, GyrI reduces microcin B17-mediated double-strand breaks in vivo, imparting protection to the cells against the toxin, substantiating the in vitro results. Thus, GyrI is an antidote to DNA gyrase-specific proteinaceous poisons encoded by plasmid addiction systems.     

In silico high-throughput virtual screening and molecular dynamics simulation study to identify inhibitor for AdeABC efflux pump of Acinetobacter baumannii

Emergence of multi-drug resistant strains of Acinetobacter baumannii has caused significant health problems and is responsible for high morbidity and mortality. Overexpression of AdeABC efflux system is one of the major mechanisms. In this study, we have focused on overcoming the drug resistance by identifying inhibitors that can effectively bind and inhibit integral membrane protein, AdeB of this efflux pump. We performed homology modeling to generate structure of AdeB using MODELLER v9.16 followed by model refinement using 3D-Refine tool and validated using PSVS, ProsaWeb, ERRAT, etc. The energy minimization of modeled protein was done using Protein preparation wizard application included in Schrodinger suite. High-throughput virtual screening of 159,868 medicinal compounds against AdeB was performed using three sequential docking modes (i.e. HTVS, SP and XP). Furthermore, absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis was done using QIKPROP. The selected 123 compounds were further analyzed for binding free energy by molecular mechanics (using prime MM-GBSA). We have also performed enrichment study (ROC curve analysis) to validate our docking results. The selected molecule and its interaction with AdeB were validated by molecular dynamics simulation (MDS) using GROMACS v5.1.4. In silico high-throughput virtual screening and MDS validation identified ZINC01155930 ((4R)-3-(cycloheptoxycarbonyl)-4-(4-etochromen-3-yl)-2-methyl-4,6,7,8-tetrahydroquinolin-5-olate) as a possible inhibitor for AdeB. Hence, it might be a suitable efflux pump inhibitor worthy of further investigation in order to be used for controlling infections caused by Acinetobacter baumannii.     

Preclinical Efficacy and Safety of a Human Embryonic Stem Cell-Derived Midbrain Dopamine Progenitor Product,MSK-DA01

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Distinct immunomodulatory properties of extracellular vesicles released by different strains of Acanthamoeba

Free living amoeba of the genus Acanthamoeba are opportunist protozoan involved in corneal, systemic, and encephalic infections in humans. Most of the mechanisms underlying intraspecies variations and pathogenicity are still unknown. Recently, the release of extracellular vesicles (EVs) by Acanthamoeba was reported. However, comparative characterization of EVs from distinct strains is not available. The aim of this study was to evaluate EVs produced by Acanthamoeba from different genotypes, comparing their proteases profile and immunomodulatory properties. EVs from four environmental or clinical strains (genotypes T1, T2, T4, and T11) were obtained by ultracentrifugation, quantitated by nanoparticle tracking analysis and analyzed by scanning and transmission electron microscopy. Proteases profile was determined by zymography and functional properties of EVs (measure of nitrite and cytokine production) were determined after peritoneal macrophage stimulation. Despite their genotype, all strains released EVs and no differences in size and/or concentration were detected. EVs exhibited a predominant activity of serine proteases (pH 7.4 and 3.5), with higher intensity in T4 and T1 strains. EVs from the environmental, nonpathogenic T11 strain exhibited a more proinflammatory profile, inducing higher levels of Nitrite, tumor necrosis factor alpha and interleukin-6 via TLR4/TLR2 than those strains with pathogenic traits (T4, T1, and T2). Preincubation with EVs treated with protease inhibitors or heating drastically decreased nitrite concentration production in macrophages. Those data suggest that immunomodulatory effects of EVs may reflect their pathogenic potential depending on the Acanthamoeba strains and are dependent on protease integrity.     

Microsatellite and Mitochondrial Diversity Analysis of Native Pigs of Indo-Burma Biodiversity Hotspot

Assessment of genetic diversity in indigenous animals is an important and essential task for animal genetic improvement studies as well as conservation decision-making. The genetic diversity and evolutionary relationships among geographically and phenotypically distinct three pig breeds/types native to Indo-Burma and Eastern Himalayan global biodiversity hotspots were determined by genotyping with a panel of 22 ISAG recommended microsatellite loci as well as sequencing partial MTRNR1gene. The mean number of alleles per locus, effective number of alleles and observed heterozygosity were found to be 11.27 ± 0.85, 5.29 ± 0.34, and 0.795 ± 0.01, respectively. The moderate F_ST value (0.115 ± 0.01) indicated a fair degree of genetic differentiation among the native breeds. The Nei’s unbiased genetic identity estimates indicated less genetic distance (0.2909) between Niang Megha and Tenyi Vo pigs than the both individually with Ghoongroo breed. The divergence time was also estimated from the microsatellite analysis. Analysis of MTRNR1gene revealed distinct clustering of native Indian pigs with Chinese pigs over European pigs. The study revealed the abundance of genetic variation within native Indian pigs and their relationships as well as genetic distances.     

Impact of urbanization on moth (Insecta: Lepidoptera: Heterocera) diversity across different urban landscapes of Delhi,India

The present study deals with the diversity of moths along with the contrasting six selected landscapes and three seasons in Delhi, India for the years 2015–16 and 2016–17. Among the 51 species of moths recorded, relative abundance of family Noctuidae (61%) was found to be the highest followed by Erebidae (21.6%) and Crambidae (13%). Species diversity was found to be the highest during pre-monsoon season, whereas among the study sites Dwarka not only had the highest relative abundance of moth species (26%) but also the highest biodiversity indexes. Prior to this study in Delhi, only documentation of this faunal group, mostly in the form of occasional observations or reporting or compilation of checklists were done which have their own significance. The findings of this study indicate the significance of the urban green areas in the city to support a wide array of moths.