Sustained exendin-4 secretion through gene therapy targeting salivary glands in two different rodent models of obesity/type 2 diabetes

Exendin-4 (Ex-4) is a Glucagon-like peptide 1 (GLP-1) receptor agonist approved for the treatment of Type 2 Diabetes (T2DM), which requires daily subcutaneous administration. In T2DM patients, GLP-1 administration is reported to reduce glycaemia and HbA1c in association with a modest, but significant weight loss. The aim of present study was to characterize the site-specific profile and metabolic effects of Ex-4 levels expressed from salivary glands (SG) in vivo, following adeno-associated virus-mediated (AAV) gene therapy in two different animal models of obesity prone to impaired glucose tolerance and T2DM, specifically, Zucker fa/fa rats and high fed diet (HFD) mice. Following percutaneous injection of AAV5 into the salivary glands, biologically active Ex-4 was detected in the blood of both animal models and expression persisted in salivary gland ductal cell until the end of the study. In treated mice, Ex-4 levels averaged 138.9±42.3 pmol/L on week 6 and in treated rats, mean circulating Ex-4 levels were 238.2±72 pmol/L on week 4 and continued to increase through week 8. Expression of Ex-4 resulted in a significant decreased weight gain in both mice and rats, significant improvement in glycemic control and/or insulin sensitivity as well as visceral adipose tissue adipokine profile. In conclusion, these results suggest that sustained site-specific expression of Ex-4 following AAV5-mediated gene therapy is feasible and may be useful in the treatment of obesity as well as trigger improved metabolic profile.     

Tracing the origins of widespread highland species: a case of Neogene diversification across the Mexican sierras in an endemic lizard

The evolutionary history of the Mexican sierras has been shaped by various geological and climatic events over the past several million years. The relative impacts of these historical events on diversification in highland taxa, however, remain largely uncertain owing to a paucity of studies on broadly‐distributed montane species. We investigated the origins of genetic diversification in widely‐distributed endemic alligator lizards in the genus Barisia to help develop a better understanding of the complex processes structuring biological diversity in the Mexican highlands. We estimated lineage divergence dates and the diversification rate from mitochondrial DNA sequences, and combined divergence dates with reconstructions of ancestral geographical ranges to track lineage diversification across geography through time. Based on our results, we inferred ten geographically structured, well supported mitochondrial lineages within Barisia. Diversification of a widely‐distributed ancestor appears tied to the formation of the Trans‐Mexican Volcanic Belt across central Mexico during the Miocene and Pliocene. The formation of filter barriers such as major river drainages may have later subdivided lineages. The results of the present study provide additional support for the increasing number of studies that suggest Neogene events heavily impacted genetic diversification in widespread montane taxa. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 382–394.     

Evolution of a complex disease resistance gene cluster in diploid Phaseolus and tetraploid Glycine

We used a comparative genomics approach to investigate the evolution of a complex nucleotide-binding (NB)-leucine-rich repeat (LRR) gene cluster found in soybean (Glycine max) and common bean (Phaseolus vulgaris) that is associated with several disease resistance (R) genes of known function, including Rpg1b (for Resistance to Pseudomonas glycinea1b), an R gene effective against specific races of bacterial blight. Analysis of domains revealed that the amino-terminal coiled-coil (CC) domain, central nucleotide-binding domain (NB-ARC [for APAF1, Resistance genes, and CED4]), and carboxyl-terminal LRR domain have undergone distinct evolutionary paths. Sequence exchanges within the NB-ARC domain were rare. In contrast, interparalogue exchanges involving the CC and LRR domains were common, consistent with both of these regions coevolving with pathogens. Residues under positive selection were overrepresented within the predicted solvent-exposed face of the LRR domain, although several also were detected within the CC and NB-ARC domains. Superimposition of these latter residues onto predicted tertiary structures revealed that the majority are located on the surface, suggestive of a role in interactions with other domains or proteins. Following polyploidy in the Glycine lineage, NB-LRR genes have been preferentially lost from one of the duplicated chromosomes (homeologues found in soybean), and there has been partitioning of NB-LRR clades between the two homeologues. The single orthologous region in common bean contains approximately the same number of paralogues as found in the two soybean homeologues combined. We conclude that while polyploidization in Glycine has not driven a stable increase in family size for NB-LRR genes, it has generated two recombinationally isolated clusters, one of which appears to be in the process of decay.     

Interspecific Competition and Speciation in Endoparasitoids

Ecological speciation occurs when inherent reproductive barriers to gene flow evolve between populations as a result of divergent natural selection. Frequency dependent effects associated with intraspecific resource competition are thought to be one important source of divergent selection facilitating ecological speciation. Interspecific competition may also play an important role in promoting population divergence. Although evidence for interspecific competition in nature is ubiquitous, there is currently little empirical data supporting its role in the speciation process. Here, we discuss two general models in which interspecific competition among species can promote ecological speciation among populations within a species. In both models, interspecific competition is the source of divergent selection driving adaption to different portions of the resource distribution, generating ecological reproductive isolation from other conspecific populations. We propose that the biology of endoparasitoids that attack phytophagous insects make model systems for studying the role of interspecific competition in ecological speciation. We describe details for one such system, the community of endoparasitic braconid wasps attacking Rhagoletis fruit flies, as a potential model for investigating competitive speciation. We conclude by hypothesizing that a model in which interspecific competition forces an inferior competitor to alternative fly hosts may be a common theme contributing to parasitoid diversification in the Rhagoletis-parasitoid system.     

Coproduction and ecological significance of naphthoquinones in carnivorous sundews (Drosera)

While the 1,4-naphthoquinone derivatives 7-methyljuglone (1) and plumbagin (2) possess a diverse and well documented array of biological activities, relatively little remains known about the functional significance of these compounds in planta and, in particular, their possible relation to carnivorous syndromes. In addition, the chemotaxonomic distribution of naphthoquinones (NQs) amongst species of Drosera L. is of phytopharmaceutical interest. Following the quantitative assessment of interspecific variation of 1 and 2 in 13 species and cultivars of Drosera, our findings demonstrate that these NQs are ubiquitously coproduced in, generally, species-specific ratios, and that 1 appears negatively associated with the occurrence of pigmentation in sundews. The prospective antifeedant function of 1 was evaluated in relation to allocation in various organs and ontogenetic phases of D. capensis L., revealing that significantly higher levels were accumulated in young and reproductive organs, most likely for defensive purposes. Investigation into the relationship between the biosynthesis of NQs and carnivory showed that production of 1 is optimally induced and localized in leaves in response to capture of insect prey. As a whole, these findings reveal the clear importance of this secondary metabolite in ecological interactions as well as holding implication for future bioactivity studies on the genus.     

Therapeutic ultrasound as a potential male contraceptive: power, frequency and temperature required to deplete rat testes of meiotic cells and epididymides of sperm determined using a commercially available system

Background

Carbamazepine (CBZ) is a first-line antiepileptic drug (AED), although it is also used for the treatments of psychiatric disorders and neuropathic pain. The CBZ utilization has been associated with male reproductive damage, including hormonal alterations, sexual dysfunction and reduction of sperm quality. The wide and long-term use of the CBZ is a common schedule in children and adolescents and alters the testosterone level in adult rats and humans. The objective of this work was to evaluate the CBZ side effects on the ventral prostate of rats from pre-puberty to sexual maturation, since the prostate is an androgen-dependent organ.

Methods

Twenty three day-old male albino Wistar rats received CBZ diluted in propylene glycol (20 mg/Kg/i.p via). The treatment lasted 20, 40 and 70 days, according to the different stages of the rat sexual maturation. At the end of each treatment period, ventral prostates were removed and histologically processed. The prostate sections were submitted to the histopathological, morphological and stereological analyses using image analysis system.

Results

Reductions of the glandular epithelium, glandular lumen and fibromuscular stroma volume of the ventral prostate were observed in adult rats treated with CBZ since the weaning. Triggering and degranulation of mast cells were observed in the fibromuscular stroma of prepubertal and pubertal CBZ treated rats.

Conclusions

The results suggest a direct effect of the CBZ on rat ventral prostate, evidenced by increase of mast cell and macrophage populations during pre-puberty and puberty causing a ventral prostate accentuated damage in the adult phase.     

Cysteine metabolism in an isolate of Lactobacillus sake: Plasmid composition and cysteine transport

Abstract Lactobacillus sake L13, an isolate from vacuum packaged beef is able to utilise cysteine as an energy source for growth in rich medium. This isolate segregates into two strains, one of which retains the ability to grow on cysteine (notated as strong cells) while the other grows only marginally (weak). Both strains possess cysteine desulfhydrase activity, but only one is able to actively transport cysteine (high affinity). Uptake is sensitive to inhibition by valinomycin, CCCP, nigericin and arsenate. Comparison of the two cell types indicates that there are two cysteine transport systems and that the alternative one is passive and of low affinity. Strong cells possess two plasmids (2.7 and 8.3 kb) while the weak strain has lost the plasmids. Curing of the strong cells results in plasmid loss and loss of the high affinity cysteine uptake system.     

Neuromuscular Organization for "Wing" Control in a Mollusc (Clione limacina) and a Bird (Columba livia): Parallels in Design

Flapping as a means of locomotion is shared by divergent groupsranging from pteropod molluscs to birds. The pteropod, Clionelimacina, exhibits two modes of locomotion, slow and fast swimming.The motor units which control swimming consist of small motoneuronsand relatively nonfatigable muscle fibers, while those involvedin fast swimming consistof large motoneurons and relativelyfatigable fibers (Satterlie et al., 1990).The pectoralis muscleof the pigeon, Columba livia, consists of two populations ofmuscle fibers distinguished by histochemistry and size. Cinematographicand electromyographic experiments suggest that the large fibersare used for takeoff and landing and the small fibers for levelflight (Dial et al., 1988). We have employed a suite of experimentaltechniques similar to those used for studies of the neuromuscularsystem of Clione to analyze a limited sample of motor unitsfrom the pectoralis of Columba. The peak tetanic tension andcontractile fatigue resistance during electrical stimulationof single alpha axons, functionally isolated from nerve filaments,was studied in 30 motor units. All units but one generated peaktetanic tensions which were less than 0.22% of whole muscletension. A high proportion (75%) of units demonstrated fatigueresistance, reflective of the demands of sustained flappingflight. These preliminary data suggest that the peripheral neuromuscularsystems of Clione and Columba share some common components forthe execution of at least two distinct modes of flapping locomotion.     

Patterns of Bat Fatalities at Wind Energy Facilities in North America

Abstract Wind has become one of the fastest growing sources of renewable energy worldwide, but widespread and often extensive fatalities of bats have increased concern regarding the impacts of wind energy development on bats and other wildlife. We synthesized available information on patterns of bat fatalities from a review of 21 postconstruction fatality studies conducted at 19 facilities in 5 United States regions and one Canadian province. Dominance of migratory, foliage- and tree-roosting lasiurine species (e.g., hoary bat [Lasiurus cinereus]) killed by turbines was consistent among studies. Bat fatalities, although highly variable and periodic, consistently peaked in late summer and fall, coinciding with migration of lasiurines and other species. A notable exception was documented fatalities of pregnant female Brazilian freetailed bats (Tadarida brasiliensis) in May and June at a facility in Oklahoma, USA, and female silver-haired bats (Lasionycteris noctivagans) during spring in Tennessee, USA, and Alberta, Canada. Most studies reported that fatalities were distributed randomly across turbines at a site, although the highest number of fatalities was often found near the end of turbine strings. Two studies conducted simultaneously in the same region documented similar timing of fatalities between sites, which suggests broader patterns of collisions dictated by weather, prey abundance, or other factors. None of the studies found differences in bat fatalities between turbines equipped with lighting required by the Federal Aviation Administration and turbines that were unlit. All studies that addressed relationships between bat fatalities and weather patterns found that most bats were killed on nights with low wind speed (<6 m/sec) and that fatalities increased immediately before and after passage of storm fronts. Weather patterns may be predictors of bat activity and fatality; thus, mitigation efforts that focus on these high-risk periods could reduce bat fatality substantially. We caution that estimates of bat fatality are conditioned by length of study and search interval and that they are biased in relation to how searcher efficiency, scavenger removal, and habitat differences were or were not accounted for. Our review will assist managers, biologists, and decision-makers with understanding unifying and unique patterns of bat fatality, biases, and limitations of existing efforts, and it will aid in designing future research needed to develop mitigation strategies for minimizing or eliminating bat fatality at wind facilities.