Characterization of casein and alpha lactalbumin of African elephant (Loxodonta africana) milk

The current research reports partial characterization of the caseins and alpha-lactalbumin (alpha-LA) of the African elephant with proposed unique structure-function properties. Extensive research has been carried out to understand the structure of the casein micelles. Crystallographic structure elucidation of caseins and casein micelles is not possible. Consequently, several models have been developed in an effort to describe the casein micelle, specifically of cow milk. Here we report the characterization of African elephant milk caseins. The kappa-caseins and beta-caseins were investigated, and their relative ratio was found to be approximately 1:8.5, whereas alpha-caseins were not detected. The gene sequence of beta-casein in the NCBI database was revisited, and a different sequence in the N-terminal region is proposed. Amino acid sequence alignment and hydropathy plots showed that the kappa-casein of African elephant milk is similar to that of other mammals, whereas the beta-casein is similar to the human protein, and displayed a section of unique AA composition and additional hydrophilic regions compared with bovine caseins. Elephant milk is destabilized by 62% alcohol, and it is speculated that the beta-casein characteristics may allow maintenance of the colloidal nature of the casein micelle, a role that was previously only associated with K-casein. The oligosaccharide content of milk was reported to be low in dairy animals but high in some other species such as humans and elephants. In the milk of the African elephant, lactose and oligosaccharides both occur at high levels. These levels are typically related to the content of alpha-LA in the mammary gland and thus point to a specialized carbohydrate synthesis, where the whey protein alpha-LA plays a role. We report the characterization of African elephant alpha-LA. Homology modeling of the alpha-LA showed that it is structurally similar to crystal structures of other mammalian species, which in turn may be an indication that its functional properties, such as lactose synthesis, should not be impaired

Superconducing Alloys with Weak and Strong Scattering: Anderson's Theorem and a Superconductor-Insulator Transition

We have studied the effects of strong impurity scattering on disordered superconductors beyond the low impurity concentration limit. By applying the full CPA to a superconductiong A-B binary alloy, we calculated the fluctuations of the local order parameters $\Delta_{A}, \Delta_{B}$ and charge densities, $n_{A}, n_{B}$ for weak and strong on site disorder. We find that for narrow band alloy s-wav e superconductors the conditions for Anderson's theorem are satisfied in general only for the case of particle-hole symmetry. In this case it is satisfied regardless whether we are in the weak or strong scattering regimes. Interestingly, we find that strong scattering leads to band splitting and in this regime for any band filling we have a critical concentration where a superconductor-insulator quantum phase transition occurs at T=0.Comment: 28 pages, 13 figure

Medical Student Engagement in a Virtual Learning Environment Positively Correlates with Course Performance and Satisfaction in Psychiatry

This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Introduction There has been a move to a “flipped classroom” (FC) in medical education. The FC promotes active learning and utilizes independent preparation prior to in-class sessions. Few studies have evaluated the effectiveness of the FC approach in medical education, specifically via virtual learning. The purpose of this study evaluates student and faculty perceptions of the FC approach and relationships between student engagement and performance. Method The first-year medical student psychiatry curriculum was redesigned with an FC approach and subsequently altered by COVID-19 to a virtual learning environment. A mixed-method approach was used to examine both qualitative assessment and quantitative performance data. Students and facilitators were invited to participate in surveys regarding the curriculum changes. Student performance data was collected via quizzes and examinations. Engagement was evaluated by student participation in National Board of Medical Examiners–style multiple-choice questions delivered via Top Hat®. Correlational analyses were used to evaluate associations between engagement and performance. T-tests were used to compare student satisfaction across 2019 and 2020. Results Performance on in-class questions was positively associated with class rank and performance (p < 0.005). More students were either satisfied or strongly satisfied (91.5%) in 2020 compared to 85.7% in 2019 (two-tailed t-test, p = 0.04). Most students (81.3%) preferred in-class questions to lectures. In 2020, 62.6% of student comments were positive regarding the psychiatry curriculum vs 33.3% in 2019. Over 61.5% of facilitators felt positive towards the changes. Conclusion Our results demonstrate a positive relationship between engagement and class performance. Students and facilitators positively perceived the approach, with students preferring in-class questions compared to lectures. Future research should evaluate overall performance on standardized tests, third-year clerkships, and number of students matching into psychiatry

Live-attenuated Mycobacterium tuberculosis vaccine MTBVAC versus BCG in adults and neonates: a randomised controlled, double-blind dose-escalation trial

Background: Infants are a key target population for new tuberculosis vaccines. We assessed the safety and immunogenicity of the live-attenuated Mycobacterium tuberculosis vaccine candidate MTBVAC in adults and infants in a region where transmission of tuberculosis is very high. Methods: We did a randomised, double-blind, BCG-controlled, dose-escalation trial at the South African Tuberculosis Vaccine Initiative site near Cape Town, South Africa. Healthy adult community volunteers who were aged 18–50 years, had received BCG vaccination as infants, were HIV negative, had negative interferon-¿ release assay (IGRA) results, and had no personal history of tuberculosis or current household contact with someone with tuberculosis were enrolled in a safety cohort. Infants born to HIV-negative women with no personal history of tuberculosis or current household contact with a person with tuberculosis and who were 96 h old or younger, generally healthy, and had not yet received routine BCG vaccination were enrolled in a separate infant cohort. Eligible adults were randomly assigned (1:1) to receive either BCG Vaccine SSI (5 × 105 colony forming units [CFU] of Danish strain 1331 in 0·1 mL diluent) or MTBVAC (5 × 105 CFU in 0·1 mL) intradermally in the deltoid region of the arm. After favourable review of 28-day reactogenicity and safety data in the adult cohort, infants were randomly assigned (1:3) to receive either BCG Vaccine SSI (2·5 × 105 CFU in 0·05 mL diluent) or MTBVAC in three sequential cohorts of increasing MTBVAC dose (2·5 × 103 CFU, 2·5 × 104 CFU, and 2·5 × 105 CFU in 0·05 mL) intradermally in the deltoid region of the arm. QuantiFERON-TB Gold In-Tube IGRA was done on days 180 and 360. For both randomisations, a pre-prepared block randomisation schedule was used. Participants (and their parents or guardians in the case of infant participants), investigators, and other clinical and laboratory staff were masked to intervention allocation. The primary outcomes, which were all measured in the infant cohort, were solicited and unsolicited local adverse events and serious adverse events until day 360; non-serious systemic adverse events until day 28 and vaccine-specific CD4 and CD8 T-cell responses on days 7, 28, 70, 180, and 360. Secondary outcomes measured in adults were local injection-site and systemic reactions and haematology and biochemistry at study day 7 and 28. Safety analyses and immunogenicity analyses were done in all participants who received a dose of vaccine. This trial is registered with ClinicalTrials.gov, number NCT02729571. Findings: Between Sept 29, 2015, and Nov 16, 2015, 62 adults were screened and 18 were enrolled and randomly assigned, nine each to the BCG and MTBVAC groups. Between Feb 12, 2016, and Sept 21, 2016, 36 infants were randomly assigned—eight to the BCG group, nine to the 2·5 × 103 CFU MTBVAC group, nine to the 2·5 × 104 CFU group, and ten to the 2·5 × 105 CFU group. Mild injection-site reactions occurred only in infants in the BCG and the 2·5 × 105 CFU MTBVAC group, with no evidence of local or regional injection-site complications. Systemic adverse events were evenly distributed across BCG and MTBVAC dose groups, and were mostly mild in severity. Eight serious adverse events were reported in seven vaccine recipients (one adult MTBVAC recipient, one infant BCG recipient, one infant in the 2·5 × 103 CFU MTBVAC group, two in the 2·5 × 104 CFU MTBVAC group, and two in the 2·5 × 105 CFU MTBVAC group), including one infant in the 2·5 × 103 CFU MTBVAC group treated for unconfirmed tuberculosis and one in the 2·5 × 105 CFU MTBVAC group treated for unlikely tuberculosis. One infant died as a result of possible viral pneumonia. Vaccination with all MTBVAC doses induced durable antigen-specific T-helper-1 cytokine-expressing CD4 cell responses in infants that peaked 70 days after vaccination and were detectable 360 days after vaccination. For the highest MTBVAC dose (ie, 2·5 × 105 CFU), these responses exceeded responses induced by an equivalent dose of the BCG vaccine up to 360 days after vaccination. Dose-related IGRA conversion was noted in three (38%) of eight infants in the 2·5 × 103 CFU MTBVAC group, six (75%) of eight in the 2·5 × 104 CFU MTBVAC group, and seven (78%) of nine in the 2·5 × 105 CFU MTBVAC group at day 180, compared with none of seven infants in the BCG group. By day 360, IGRA reversion had occurred in all three infants (100%) in the 2·5 × 103 CFU MTBVAC group, four (67%) of the six in the 2·5 × 104 CFU MTBVAC group, and three (43%) of the seven in the 2·5 × 105 CFU MTBVAC group. Interpretation: MTBVAC had acceptable reactogenicity, and induced a durable CD4 cell response in infants. The evidence of immunogenicity supports progression of MTBVAC into larger safety and efficacy trials, but also confounds interpretation of tests for M tuberculosis infection, highlighting the need for stringent endpoint definition. Funding: Norwegian Agency for Development Cooperation, TuBerculosis Vaccine Initiative, UK Department for International Development, and Biofabri

Nematode effector proteins: an emerging paradigm of parasitism

Phytonematodes use a stylet and secreted effectors to modify host cells and ingest nutrients to support their growth and development. The molecular function of nematode effectors is currently the subject of intense investigation. In this review, we summarize our current understanding of nematode effectors, with a particular focus on proteinaceous stylet-secreted effectors of sedentary endoparasitic phytonematodes, for which a wealth of information has surfaced in the past 10 yr. We provide an update on the effector repertoires of several of the most economically important genera of phytonematodes and discuss current approaches to dissecting their function. Lastly, we highlight the latest breakthroughs in effector discovery that promise to shed new light on effector diversity and function across the phylum Nematoda

HelmCoP: An Online Resource for Helminth Functional Genomics and Drug and Vaccine Targets Prioritization

A vast majority of the burden from neglected tropical diseases result from helminth infections (nematodes and platyhelminthes). Parasitic helminthes infect over 2 billion, exerting a high collective burden that rivals high-mortality conditions such as AIDS or malaria, and cause devastation to crops and livestock. The challenges to improve control of parasitic helminth infections are multi-fold and no single category of approaches will meet them all. New information such as helminth genomics, functional genomics and proteomics coupled with innovative bioinformatic approaches provide fundamental molecular information about these parasites, accelerating both basic research as well as development of effective diagnostics, vaccines and new drugs. To facilitate such studies we have developed an online resource, HelmCoP (Helminth Control and Prevention), built by integrating functional, structural and comparative genomic data from plant, animal and human helminthes, to enable researchers to develop strategies for drug, vaccine and pesticide prioritization, while also providing a useful comparative genomics platform. HelmCoP encompasses genomic data from several hosts, including model organisms, along with a comprehensive suite of structural and functional annotations, to assist in comparative analyses and to study host-parasite interactions. The HelmCoP interface, with a sophisticated query engine as a backbone, allows users to search for multi-factorial combinations of properties and serves readily accessible information that will assist in the identification of various genes of interest. HelmCoP is publicly available at: http://www.nematode.net/helmcop.html

The map-1 Gene Family in Root-Knot Nematodes, Meloidogyne spp.: A Set of Taxonomically Restricted Genes Specific to Clonal Species

Taxonomically restricted genes (TRGs), i.e., genes that are restricted to a limited subset of phylogenetically related organisms, may be important in adaptation. In parasitic organisms, TRG-encoded proteins are possible determinants of the specificity of host-parasite interactions. In the root-knot nematode (RKN) Meloidogyne incognita, the map-1 gene family encodes expansin-like proteins that are secreted into plant tissues during parasitism, thought to act as effectors to promote successful root infection. MAP-1 proteins exhibit a modular architecture, with variable number and arrangement of 58 and 13-aa domains in their central part. Here, we address the evolutionary origins of this gene family using a combination of bioinformatics and molecular biology approaches. Map-1 genes were solely identified in one single member of the phylum Nematoda, i.e., the genus Meloidogyne, and not detected in any other nematode, thus indicating that the map-1 gene family is indeed a TRG family. A phylogenetic analysis of the distribution of map-1 genes in RKNs further showed that these genes are specifically present in species that reproduce by mitotic parthenogenesis, with the exception of M. floridensis, and could not be detected in RKNs reproducing by either meiotic parthenogenesis or amphimixis. These results highlight the divergence between mitotic and meiotic RKN species as a critical transition in the evolutionary history of these parasites. Analysis of the sequence conservation and organization of repeated domains in map-1 genes suggests that gene duplication(s) together with domain loss/duplication have contributed to the evolution of the map-1 family, and that some strong selection mechanism may be acting upon these genes to maintain their functional role(s) in the specificity of the plant-RKN interactions

Characterisation of a Desmosterol Reductase Involved in Phytosterol Dealkylation in the Silkworm, Bombyx mori

Most species of invertebrate animals cannot synthesise sterols de novo and many that feed on plants dealkylate phytosterols (mostly C29 and C28) yielding cholesterol (C27). The final step of this dealkylation pathway involves desmosterol reductase (DHCR24)-catalysed reduction of desmosterol to cholesterol. We now report the molecular characterisation in the silkworm, Bombyx mori, of such a desmosterol reductase involved in production of cholesterol from phytosterol, rather than in de novo synthesis of cholesterol. Phylogenomic analysis of putative desmosterol reductases revealed the occurrence of various clades that allowed for the identification of a strong reductase candidate gene in Bombyx mori (BGIBMGA 005735). Following PCR-based cloning of the cDNA (1.6 kb) and its heterologous expression in Saccharomyces cerevisae, the recombinant protein catalysed reduction of desmosterol to cholesterol in an NADH- and FAD- dependent reaction

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation