COVID‐19 lockdown frees wildlife to roam but increases poaching threats in Nepal

To contain transmission of COVID‐19, lockdowns or strict restrictions of people''s mobility outside their residences were instituted in a majority of countries worldwide, including Nepal, where the first phase of nationwide lockdown was observed from 24 March to 21 July 2020. This sudden halt in human outdoor activities brought positive and negative impacts on forests and wildlife. We undertook a study to learn the impact of the COVID‐19 lockdown on wildlife and forests in the protected areas (PAs) of Nepal. Between July and September 2020, data on illegal activities recorded by the staff of PAs and also those reported by media were collected and analyzed. Key informant interviews (KII) were done with the park officers and security personnel by virtual communication (telephone, messenger app, and video call) to collect detailed information and for corroboration. The collected data were categorized into four groups: (a) wildlife killed, (b) wildlife injured, (c) arrest incidents related to forest crime, and (d) arrest incidents related to wildlife crime. Data from the fiscal year 2019–2020 were analyzed, comparing before lockdown and after. Among 20 PAs investigated during the lockdown, the study found substantial increases in wildlife death in two PAs, Banke National Park, and Bardia National Park. Similarly, Chitwan National Park (CNP) and Shivapuri Nagarjun National Park (SNNP) witnessed a rise in wildlife poaching. CNP and SNNP are located close to densely populated cities and also have human settlements in their peripheries. Wildlife was sighted freely roaming inside PAs during the lockdown, presumably because the absence of visitors and human activities during the lockdown decreased disturbance. Thus, the wildlife was enjoying the freedom of movement on the one hand, and on the other hand was threatened by poachers, many of whom were laid off from other activities and were taking advantage of the lapse in security.     

A Bayesian semiparametric approach for incorporating longitudinal information on exposure history for inference in case-control studies

In a typical case-control study, exposure information is collected at a single time point for the cases and controls. However, case-control studies are often embedded in existing cohort studies containing a wealth of longitudinal exposure history about the participants. Recent medical studies have indicated that incorporating past exposure history, or a constructed summary measure of cumulative exposure derived from the past exposure history, when available, may lead to more precise and clinically meaningful estimates of the disease risk. In this article, we propose a flexible Bayesian semiparametric approach to model the longitudinal exposure profiles of the cases and controls and then use measures of cumulative exposure based on a weighted integral of this trajectory in the final disease risk model. The estimation is done via a joint likelihood. In the construction of the cumulative exposure summary, we introduce an influence function, a smooth function of time to characterize the association pattern of the exposure profile on the disease status with different time windows potentially having differential influence/weights. This enables us to analyze how the present disease status of a subject is influenced by his/her past exposure history conditional on the current ones. The joint likelihood formulation allows us to properly account for uncertainties associated with both stages of the estimation process in an integrated manner. Analysis is carried out in a hierarchical Bayesian framework using reversible jump Markov chain Monte Carlo algorithms. The proposed methodology is motivated by, and applied to a case-control study of prostate cancer where longitudinal biomarker information is available for the cases and controls.     

Catfish (Clarias batrachus) serum lectin recognizes polyvalent Tn [alpha-D-GalpNAc1-Ser/Thr], Talpha [beta-D-Galp-(1-->3)-alpha-D-GalpNAc1-Ser/Thr], and II [beta-D-Galp(1-->4)-beta-D-GlcpNAc1-] mammalian glycotopes

A new calcium dependent GalNAc/Gal specific lectin was isolated from the serum of Indian catfish, Clarias batrachus and designated as C. batrachus lectin (CBL). It is a disulfide-linked homodecameric lectin of 74.65kDa subunits and the oligomeric form is essential for its activity. Binding specificity of CBL was investigated by enzyme-linked lectin-sorbent assay using a series of simple sugars, polysaccharides, and glycoproteins. GalNAc was more potent inhibitor than Gal; and alpha glycosides of both were more inhibitory than their beta counterparts. CBL showed maximum affinity for human tumor-associated Tn-antigens (GalNAcalpha1-Ser/Thr) at the molecular level and was 3.5 times higher than GalNAc. CBL interacted strongly with polyvalent Tn and Talpha (Galbeta1,3GalNAcalpha1-) as well as multivalent-II (Galbeta1,4GlcNAcbeta1-) antigens containing glycoproteins and intensity of inhibition was 10(3)-10(5) times more than monovalent ones. The overall specificity of CBL lies in the order of polyvalent Tn, Talpha and II>monovalent TnMe-alphaGalNAc>monovalent Talpha> Me-betaGalNAc>Me-alphaGal>monovalent T>GalNAc>monovalent F>monovalent II>Me-betaGal>Gal.     

Functional analysis of the essential GTP-binding-protein-coding gene cgtA of Vibrio cholerae

The cgtA gene, coding for the conserved G protein CgtA, is essential in bacteria. In contrast to a previous report, here we show by using genetic analysis that cgtA is essential in Vibrio cholerae even in a Delta relA background. Depletion of CgtA affected the growth of V. cholerae and rendered the cells highly sensitive to the replication inhibitor hydroxyurea. Overexpression of V. cholerae CgtA caused distinct elongation of Escherichia coli cells. Deletion analysis indicated that the C-terminal end of CgtA plays a critical role in its proper function.     

Workers of the primitively eusocial wasp <Emphasis Type="Italic">Ropalidia marginata</Emphasis> do not perceive their queen across a wire mesh partition

Queens of primitively eusocial wasps generally have active and behaviourally dominant queens who use physical aggression to suppress worker reproduction. Although a Ropalidia marginata queen is strikingly docile and behaviourally non-dominant, she is completely successful in maintaining reproductive monopoly. R. marginata queens must achieve such reproductive monopoly by some means other than overt physical aggression. Upon loss or removal of the queen, one of the workers (referred to as the potential queen) becomes extremely aggressive and will eventually go on to become the next queen of the colony, if the original queen is not returned. The fact that potential queens are not discernible in the presence of the queen but become obvious within minutes after removal of the queen raises the question of how workers in general and the potential queens in particular, perceive the presence or absence of their queens. Here, we have conducted experiments in which we separate half of the workers from their queen by a wire mesh screen and study their behavioural response to such separation. We demonstrate that the presence of the queen is not perceived across the wire mesh screen, which suggests that if the queen uses a pheromone to signal her presence, then that pheromone is not very volatile.     

Interaction of isoquinoline alkaloid palmatine with deoxyribonucleic acids: binding heterogeneity, and conformational and thermodynamic aspects

The binding heterogeneity, conformational aspects, and energetics of the interaction of the cytotoxic plant alkaloid palmatine have been studied with various natural and synthetic DNAs. The alkaloid binds to calf thymus and Escherichia coli DNA that have mixed AT and GC sequences in almost equal proportions with positive cooperativity, while, with Clostridium perfringens and Micrococcus lysodeikticus DNA with predominantly high AT and GC sequences, respectively, noncooperative binding was observed. On further investigation with synthetic DNAs, the binding was observed to be cooperative with polymers like poly(dA).poly(dT) and poly(dG).poly(dC) having poly(purine)poly(pyrimidine) sequences, while with polymers poly(dA-dT).poly(dA-dT), poly(dA-dC).poly(dG-dT) and poly(dG-dC).poly(dG-dC), which have alternating purine-pyrimidine sequences, a non-cooperative binding phenomenon was observed. This suggests the binding heterogeneity of palmatine to the two types of sequences of base pairs. Circular dichroism (CD) studies revealed that the binding induced conformational changes in all the DNAs, but more importantly, the bound alkaloid molecules acquired induced optical activity, and the extent was dependent on the AT content and showed AT base-pair specificity. Energetics of the interaction of the alkaloid studied by highly sensitive isothermal titration calorimetry revealed that the binding was in most cases exothermic and favored by both enthalpy and entropy changes, while, in the case of the homo and hetero AT polymers, the same was predominantly entropy-driven. This study defines base-pair-dependent heterogeneity, conformational aspects, and energetics of palmatine binding to DNA.     

We know that the wasps 'know': cryptic successors to the queen in Ropalidia marginata

Unlike other primitively eusocial wasps, Ropalidia marginata colonies are usually headed by remarkably docile and behaviourally non-dominant queens who are nevertheless completely successful in maintaining reproductive monopoly. As in other species, loss of the queen results in one of the workers taking over as the next queen. But unlike in other species, here, the queen's successor cannot be predicted on the basis of dominance rank, other behaviours, age, body size or even ovarian development, in the presence of the former queen. But the swiftness with which one and only one individual becomes evident as the potential queen led us to suspect that there might be a designated successor to the queen known to the wasps, even though we cannot identify her in the queen's presence. Here, we present the results of experiments that support such a 'cryptic successor' hypothesis, and thereby lend credence to the idea that queen (and potential queen) pheromones act as honest signals of their fertility, in R. marginata.     

Lectin-binding assay by polyethylene glycol 8000

A quantitative lectin-binding assay using a precipitation technique and polyethylene glycol 8000 (PEG) as a precipitating agent has been described. Carcinoscorpin, a sialic acid-binding lectin isolated from the hemolymph of Indian horseshoe crab, Carcinoscorpius rotunda cauda, and iodinated fetuin, a sialoglycoprotein, were appropriately incubated as the components of the binding assay. The specific interaction between these two components developed the lectin-glycoprotein-bound complex. This was subsequently precipitated by the addition of PEG together with a coprecipitant gamma-globulin. Radioactivity of the precipitated bound complex was estimated to quantify the binding. The formation of the bound complex was effectively inhibited by a specific sialodisaccharide, O-(N-acetylneuraminyl)-(2----6)-2-acetamido-2-deoxygalactitol, implying the specific interaction for such precipitation. The probable effect of PEG was to stabilize the bound complex, precipitating it along with added gamma-globulin. This was further evident from the prevention of dissociation of the bound complex and increased binding of glycoprotein to the immobilized lectin in the presence of PEG. The assay was also applicable to other sialoglycoproteins such as alpha 1-acid glycoprotein and human chorionic gonadotropin. Moreover, the method yielded a saturation plateau with a characteristic hyperbolic binding curve. The assay was simple, quick, safe, economic, and highly sensitive.     

Sub-cellular internalization and organ specific oral delivery of PABA nanoparticles by side chain variation

Background  

Organic nanomaterials having specific biological properties play important roles in in vivo delivery and clearance from the live cells. To develop orally deliverable nanomaterials for different biological applications, we have synthesized several fluorescently labelled, self-assembled PABA nanoparticles using possible acid side chain combinations and tested against insect and human cell lines and in vivo animal model. Flurophores attached to nanostructures help in rapid in vivo screening and tracking through complex tissues. The sub-cellular internalization mechanism of the conjugates was determined. A set of physio-chemical parameters of engineered nanoskeletons were also defined that is critical for preferred uptake in multiple organs of live Drosophila.