Persistence to Unrewarding Feeding Locations by Honeybee Foragers (Apis mellifera): the Effects of Experience,Resource Profitability and Season

Honeybee foragers that find a profitable food source quickly establish spatiotemporal memories, which allow them to return to this foraging site on subsequent days. The aim of this study was to investigate how the previous experience of honeybee foragers at a feeding location affects their persistence at that location once food is no longer available. We hypothesised that persistence would be greater to locations that were more rewarding (closer to the hive, higher concentration of sucrose solution), for which a bee had greater prior experience (0.5‐h vs. 2‐h training access), and at times of the year of lower nectar availability in the environment. We studied individually marked worker bees from four colonies trained to sucrose‐solution feeders. Our results support most of these predictions. Persistence, measured both in duration and number of visits, was greater to locations that previously offered sucrose solution of higher concentration (2 m vs. 1 m ) or were closer to the hive (20 m vs. 450 m). Persistence was also greater in bees that had longer access at the feeder before the syrup was terminated (2 h vs. 0.5 h). However, contrary to our prediction, persistence was not higher in the season of the lowest nectar availability in the environment in the study year. In summary, honeybees show considerable persistence at foraging sites that ceased providing rewards. The decision to abandon a foraging site depends on the profitability the forager experienced when the foraging site was still rewarding.     

Partial trisomy 7q and monosomy 13q in a child with disorder of sex development: Phenotypic and genotypic findings

Terminal 7q duplication and terminal 13q deletion are two conditions with variable phenotypes including microcephaly, thumb a-/hypoplasia, cortical dysplasia, microphtalmia, intellectual disability and dysmorphic features. We describe a boy born to a mother with a reciprocal t (7;13) who combines both a terminal 7q33-qter duplication and terminal 13q33-qter deletion through the inheritance of a derivative chromosome 13 (der (13)). The patient presented with developmental delay, facial and non-facial dysmorphic features, hypertonia, genital abnormality and skeletal malformation but no thumb a-/hypoplasia or microphtalmia. Knowing the exact breakpoints of his chromosomal aberrations using high resolution array CGH (aCGH) and comparison of his phenotypes with those of 24 and 59 previously published cases of 7q duplication and 13q deletion, respectively, allow us to further narrow the size of the proposed critical regions for microcephaly, thumb a-/hypoplasia and hypo/hypertonia on chromosome 13.     

Strategic genome-scale prioritization of unique drug targets: A case study of Streptococcus gordonii

The current reach of genomics extends facilitated identification of microbial virulence factors, a primary objective for antimicrobial drug and vaccine design. Many putative proteins are yet to be identified which can act as potent drug targets. There is lack and limitation of methods which appropriately combine several omics ways for putative and new drug target identification. The study emphasizes a combined bioinformatic and theoretical method of screening unique and putative drug targets, lacking similarity with experimentally reported essential genes and drug targets. Synteny based comparison was carried out with 11 streptococci considering S. gordonii as reference genome. It revealed 534 non-homologous genes of which 334 were putative. Similarity search against host proteome, metabolic pathway annotation and subcellular localization predication identified 16 potent drug targets. This is a first attempt of several combinational approaches of similarity search with target protein structural features for screening drug targets, yielding a pipeline which can be substantiated to other human pathogens.     

Computational simulation of internal bone remodelling around dental implants: a sensitivity analysis

This study aimed to predict the distribution of bone trabeculae, as a density change per unit time, around a dental implant based on applying a selected mathematical remodelling model. The apparent bone density change as a function of the mechanical stimulus was the base of the applied remodelling model that describes disuse and overload bone resorption. The simulation was tested in a finite element model of a screw-shaped dental implant in an idealised bone segment. The sensitivity of the simulation to different mechanical parameters was investigated; these included element edge length, boundary conditions, as well as direction and magnitude of the implant loads. The alteration in the mechanical parameters had a significant influence on density distribution and model stability, in particular at the cortical bone region. The remodelling model could succeed to achieve trabeculae-like structure around osseointegrated dental implants. The validation of this model to a real clinical case is required.     

Production of avian influenza virus vaccine using primary cell cultures generated from host organs

The global availability of a therapeutically effective influenza virus vaccine during a pandemic remains a major challenge for the biopharmaceutical industry. Long production time, coupled with decreased supply of embryonated chicken eggs (ECE), significantly affects the conventional vaccine production. Transformed cell lines have attained regulatory approvals for vaccine production. Based on the fact that the avian influenza virus would infect the cells derived from its natural host, the viral growth characteristics were studied on chicken embryo-derived primary cell cultures. The viral propagation was determined on avian origin primary cell cultures, transformed mammalian cell lines, and in ECE. A comparison was made between these systems by utilizing various cell culture-based assays. In-vitro substrate susceptibility and viral infection characteristics were evaluated by performing hemagglutination assay (HA), 50 % tissue culture infectious dose (TCID₅₀) and monitoring of cytopathic effects (CPE) caused by the virus. The primary cell culture developed from chicken embryos showed stable growth characteristics with no contamination. HA, TCID₅₀, and CPE exhibited that these cell systems were permissive to viral infection, yielding 2–10 times higher viral titer as compared to mammalian cell lines. Though the viral output from the ECE was equivalent to the chicken cell culture, the time period for achieving it was decreased to half. Some of the prerequisites of inactivated influenza virus vaccine production include generation of higher vial titer, independence from exogenous sources, and decrease in the production time lines. Based on the tests, it can be concluded that chicken embryo primary cell culture addresses these issues and can serve as a potential alternative for influenza virus vaccine production.     

α-Tocopherol Modifies Lead Induced Functional Changes at Murine Neuromuscular Junction

Lead impacts neuromuscular junction and might induce skeletal muscle weakness. Antioxidants may prevent toxic actions of lead on muscle. In this study, resting membrane potentials, endplate potentials, miniature endplate potentials (MEPPs) and isometric twitch tensions were recorded to investigate effects of α-tocopherol (Vitamin E) on lead induced changes at murine dorsiflexor muscle. Moreover, levels of endplate nicotinic receptors were measured by receptor autoradiography. Forty rats were divided into four groups (lead alone, α-tocopherol, lead plus α-tocopherol and saline). Lead (1?mg/kg, i.p.), was administered daily for 2 weeks and α-tocopherol (100?mg/kg, i.p.) was given daily for 3 weeks. Lead treatment significantly reduced twitch tension (from 4.4±0.4 to 2.2±0.3?g) and delayed half time of decay. MEPP frequencies and quantal content were also significantly reduced after lead treatment. Pretreatment with α-tocopherol reversed twitch tension reduction (4.1±0.3?g) and modified lead induced delay in half time of decay. Similarly, α-tocopherol modified the negative actions of lead exposure on MEPP frequencies and quantal content. Receptor autoradiographic studies revealed significant increase of nicotinic receptor levels at the endplate region of flexor muscle in lead treated mice. However, animals treated with lead plus α-tocopherol showed significantly decreased levels of nicotinic receptors. α-Tocopherol appears to protect against lead induced neuromuscular dysfunction. These effects of α-tocopherol are possibly mediated via a free radical mechanism or modification of calcium homeostasis.     

The grape antioxidant resveratrol for skin disorders: promise, prospects, and challenges

Resveratrol, a phytoalexin antioxidant found in red grapes, has been shown to have both chemopreventive and therapeutic effects against many diseases and disorders, including those of the skin. Studies have shown protective effects of resveratrol against ultraviolet radiation-mediated oxidative stress and cutaneous damages including skin cancer. Because many of the skin conditions stem from ultraviolet radiation and oxidative stress, this antioxidant appears to have promise and prospects against a wide range of cutaneous disorders including skin aging and skin cancers. However, there are a few roadblocks in the way of this promising agent regarding its translation from the bench to the bedside. This review discusses the promise and prospects of resveratrol in the management of skin disorders and the associated challenges.     

Genome sequences of the biotechnologically important Bacillus megaterium strains QM B1551 and DSM319

Bacillus megaterium is deep-rooted in the Bacillus phylogeny, making it an evolutionarily key species and of particular importance in understanding genome evolution, dynamics, and plasticity in the bacilli. B. megaterium is a commercially available, nonpathogenic host for the biotechnological production of several substances, including vitamin B(12), penicillin acylase, and amylases. Here, we report the analysis of the first complete genome sequences of two important B. megaterium strains, the plasmidless strain DSM319 and QM B1551, which harbors seven indigenous plasmids. The 5.1-Mbp chromosome carries approximately 5,300 genes, while QM B1551 plasmids represent a combined 417 kb and 523 genes, one of the largest plasmid arrays sequenced in a single bacterial strain. We have documented extensive gene transfer between the plasmids and the chromosome. Each strain carries roughly 300 strain-specific chromosomal genes that account for differences in their experimentally confirmed phenotypes. B. megaterium is able to synthesize vitamin B(12) through an oxygen-independent adenosylcobalamin pathway, which together with other key energetic and metabolic pathways has now been fully reconstructed. Other novel genes include a second ftsZ gene, which may be responsible for the large cell size of members of this species, as well as genes for gas vesicles, a second β-galactosidase gene, and most but not all of the genes needed for genetic competence. Comprehensive analyses of the global Bacillus gene pool showed that only an asymmetric region around the origin of replication was syntenic across the genus. This appears to be a characteristic feature of the Bacillus spp. genome architecture and may be key to their sporulating lifestyle.