Nicotine self-medication of cognitive-attentional processing

This article selectively reviews research concerning nicotine's effects on cognition, including the neurobiological mechanism for these effects, task and experimental features that may be important for elucidating these effects, and why these effects may have amplified motivational significance among smokers with cognitive deficit. Nicotine has effects on various cognitive processes, though most studies in humans have focused on the amelioration of cognitive deficits experienced during drug withdrawal. The direct cognitive-enhancing effect of nicotine remains a controversial topic. The relationship between attentional and non-attentional cognitive effects of nicotine is discussed in the context of cognitive self-medication. Further research should include theory-driven examination of cognitive effects of nicotine, and develop targeted smoking cessation programs based on an improved understanding of the role of cognitive self-medication in high-risk individuals.     

Insights into the evolutionary origins of clostridial neurotoxins from analysis of the <Emphasis Type="Italic">Clostridium botulinum</Emphasis> strain A neurotoxin gene cluster

Background  

Clostridial neurotoxins (CNTs) are the most deadly toxins known and causal agents of botulism and tetanus neuroparalytic diseases. Despite considerable progress in understanding CNT structure and function, the evolutionary origins of CNTs remain a mystery as they are unique to Clostridium and possess a sequence and structural architecture distinct from other protein families. Uncovering the origins of CNTs would be a significant contribution to our understanding of how pathogens evolve and generate novel toxin families.     

Studies on the actin-binding protein HS1 in platelets

Background  

The platelet cytoskeleton mediates the dramatic change in platelet morphology that takes place upon activation and stabilizes thrombus formation. The Arp2/3 complex plays a vital role in these processes, providing the protrusive force for lamellipodia formation. The Arp2/3 complex is highly regulated by a number of actin-binding proteins including the haematopoietic-specific protein HS1 and its homologue cortactin. The present study investigates the role of HS1 in platelets using HS1^-/- mice.     

Does inbreeding affect the extinction risk of small populations?: predictions from Drosophila

A fundamental assumption underlying the importance of genetic risks within conservation biology is that inbreeding increases the extinction probability of populations. Although inbreeding has been shown to have a detrimental impact on individual fitness, its contribution to extinction is still poorly understood. We have studied the consequences of different levels of prior inbreeding for the persistence of small populations using Drosophila melanogaster as a model organism. To this end, we determined the extinction rate of small vial populations differing in the level of inbreeding under both optimal and stress conditions, i.e. high temperature stress and ethanol stress. We show that inbred populations have a significantly higher short‐term probability of extinction than non‐inbred populations, even for low levels of inbreeding, and that the extinction probability increases with increasing inbreeding levels. In addition, we observed that the effects of inbreeding become greatly enhanced under stressful environmental conditions. More importantly, our results show that the impact of environmental stress becomes significantly greater for higher inbreeding levels, demonstrating explicitly that inbreeding and environmental stress are not independent but can act synergistically. These effects seem long lasting as the impact of prior inbreeding was still qualitatively the same after the inbred populations had been expanded to appreciable numbers and maintained as such for approximately 50 generations. Our observations have significant consequences for conservation biology.     

Phenetic distances in the Drosophila melanogaster-subgroup species and oviposition-site preference for food components

Oviposition-site preferences (O.S.P.) have been investigated in females of six sibling species of the Drosophila melanogaster subgroup. O.S.P. were determined for standard food components and yeast genotypes. Females of all species showed a strong preference for complete medium and avoidance of pure agar as an egg-deposition site.Ecological trees of the species on the basis of rank correlations were constructed. In no-choice situations they agree with phylogenetic trees obtained by different means but in choice situations they do not agree too well.All species showed a high egg production on live yeast compared with standard medium (with killed yeast) and D. erecta females demonstrated discrimination between yeast genotypes. Niche breadth calculated from survival on the sterol mutant yeasts correlated fairly well with phylogenetic trees.     

PCR detection of psychrotolerant clostridia associated with deep tissue spoilage of vacuum-packed chilled meats

AIMS: To develop a practical molecular procedure that directly (without isolation) and specifically detects the presence of clostridia, which cause the deep tissue spoilage condition. METHODS AND RESULTS: A primer set was designed and a PCR amplification procedure developed to detect the presence of Clostridium algidicarnis and Cl. putrefaciens 16S rDNA gene fragments in meat. The procedure yielded amplicons of the expected size with homologous DNA templates, but failed to give PCR products with DNAs from 47 food clostridia and common meat spoilage micro-organisms. The minimum level of detection was 10(4) cfu g-1 for nonenriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, the presence of Cl. algidicarnis and/or Cl. putrefaciens was confirmed in a swab sample taken from the cartilage of an ovine stifle joint, which on opening exhibited strong offensive odours. CONCLUSIONS: The developed method can be used for rapid detection of clostridia causing deep tissue spoilage in commercial vacuum packs. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of deep tissue clostridial spoilage in commercial vacuum-packed chilled meats.     

Aquatic metagenomes implicate Thaumarchaeota in global cobalamin production

Cobalamin (vitamin B₁₂) is a complex metabolite and essential cofactor required by many branches of life, including most eukaryotic phytoplankton. Algae and other cobalamin auxotrophs rely on environmental cobalamin supplied from a relatively small set of cobalamin-producing prokaryotic taxa. Although several Bacteria have been implicated in cobalamin biosynthesis and associated with algal symbiosis, the involvement of Archaea in cobalamin production is poorly understood, especially with respect to the Thaumarchaeota. Based on the detection of cobalamin synthesis genes in available thaumarchaeotal genomes, we hypothesized that Thaumarchaeota, which are ubiquitous and abundant in aquatic environments, have an important role in cobalamin biosynthesis within global aquatic ecosystems. To test this hypothesis, we examined cobalamin synthesis genes across sequenced thaumarchaeotal genomes and 430 metagenomes from a diverse range of marine, freshwater and hypersaline environments. Our analysis demonstrates that all available thaumarchaeotal genomes possess cobalamin synthesis genes, predominantly from the anaerobic pathway, suggesting widespread genetic capacity for cobalamin synthesis. Furthermore, although bacterial cobalamin genes dominated most surface marine metagenomes, thaumarchaeotal cobalamin genes dominated metagenomes from polar marine environments, increased with depth in marine water columns, and displayed seasonality, with increased winter abundance observed in time-series datasets (e.g., L4 surface water in the English Channel). Our results also suggest niche partitioning between thaumarchaeotal and cyanobacterial ribosomal and cobalamin synthesis genes across all metagenomic datasets analyzed. These results provide strong evidence for specific biogeographical distributions of thaumarchaeotal cobalamin genes, expanding our understanding of the global biogeochemical roles played by Thaumarchaeota in aquatic environments.     

A novel autophagy modulator 6-Bio ameliorates SNCA/α-synuclein toxicity

Parkinson disease (PD) is a life-threatening neurodegenerative movement disorder with unmet therapeutic intervention. We have identified a small molecule autophagy modulator, 6-Bio that shows clearance of toxic SNCA/α-synuclein (a protein implicated in synucleopathies) aggregates in yeast and mammalian cell lines. 6-Bio induces autophagy and dramatically enhances autolysosome formation resulting in SNCA degradation. Importantly, neuroprotective function of 6-Bio as envisaged by immunohistology and behavior analyses in a preclinical model of PD where it induces autophagy in dopaminergic (DAergic) neurons of mice midbrain to clear toxic protein aggregates suggesting that it could be a potential therapeutic candidate for protein conformational disorders.     

<i>Trichoderma</i> spp. fostering growth on <i>Capsicum chinense</i> Jacq. seedlings and antagonistic against <i>Meloidogyne incognita</i>

Fourteen native strains of Trichoderma spp. from wildand agricultural pathosystems in the state of Yucatan, Mexico, with growth-promoting ability of Capsicum chinense Jacq. seedlings were evaluated and antagonistic effect of their filtrate against second-stage juveniles (J2) of Meloidogyne incognita. The strains Th05-02 and Th27-08 showed the best significant effects on plant hight variable increments 55.57 and 47.62%, theTh07-04 with 29.48% more root length, theTh02-01 and Th07-04 isolates increased from 48.71 to 84.61% in volume radical and 53.40% of total dry biomass. Statistical analysis (p≤0.001) of Th43 and Th43-13-14 filtrates caused 100% mortality at 24 and 48h. In the test of reversibility to 24 h after replacing the filtrates Th43-13, Th43-14, TH09-06 and TH20-07 by sterile distilled water, the J2 did not recover their viability, so they were considered as the best potential strains of Trichoderma spp. with antagonistic capacity in J2 of M.incognita.     

Immunogenicity and efficacy of a chimpanzee adenovirus-vectored Rift Valley Fever vaccine in mice

Background

Rift Valley Fever (RVF) is a viral zoonosis that historically affects livestock production and human health in sub-Saharan Africa, though epizootics have also occurred in the Arabian Peninsula. Whilst an effective live-attenuated vaccine is available for livestock, there is currently no licensed human RVF vaccine. Replication-deficient chimpanzee adenovirus (ChAd) vectors are an ideal platform for development of a human RVF vaccine, given the low prevalence of neutralizing antibodies against them in the human population, and their excellent safety and immunogenicity profile in human clinical trials of vaccines against a wide range of pathogens.

Methods

Here, in BALB/c mice, we evaluated the immunogenicity and efficacy of a replication-deficient chimpanzee adenovirus vector, ChAdOx1, encoding the RVF virus envelope glycoproteins, Gn and Gc, which are targets of virus neutralizing antibodies. The ChAdOx1-GnGc vaccine was assessed in comparison to a replication-deficient human adenovirus type 5 vector encoding Gn and Gc (HAdV5-GnGc), a strategy previously shown to confer protective immunity against RVF in mice.

Results

A single immunization with either of the vaccines conferred protection against RVF virus challenge eight weeks post-immunization. Both vaccines elicited RVF virus neutralizing antibody and a robust CD8⁺ T cell response.

Conclusions

Together the results support further development of RVF vaccines based on replication-deficient adenovirus vectors, with ChAdOx1-GnGc being a potential candidate for use in future human clinical trials.