Fibre Optic SPR Sensor Using Functionalized CNTs for the Detection of SMX: Comparison with Enzymatic Approach

Plasmonics - A novel approach for the detection of sulfamethaxazole (SMX) based on fibre optic surface plasmon resonance (SPR) technique and functionalized carbon nanotubes (CNTs) is proposed for 0...     

Lactate dehydrogenase (LDH) gene duplication during chordate evolution: the cDNA sequence of the LDH of the tunicate Styela plicata

L-Lactate dehydrogenase (L-LDH, E.C. 1.1.1.27) is encoded by two or three loci in all vertebrates examined, with the exception of lampreys, which have a single LDH locus. Biochemical characterizations of LDH proteins have suggested that a gene duplication early in vertebrate evolution gave rise to Ldh-A and Ldh-B and that an additional locus, Ldh-C arose in a number of lineages more recently. Although some phylogenetic studies of LDH protein sequences have supported this pattern of gene duplication, others have contradicted it. In particular, a number of studies have suggested that Ldh-C represents the earliest divergence among vertebrate LDHs and that it may have diverged from the other loci well before the origin of vertebrates. Such hypotheses make explicit statements about the relationship of vertebrate and invertebrate LDHs, but to date, no closely related invertebrate LDH sequences have been available for comparison. We have attempted to provide further data on the timing of gene duplications leading to multiple vertebrate LDHs by determining the cDNA sequence of the LDH of the tunicate Styela plicata. Phylogenetic analyses of this and other LDH sequences provide strong support for the duplications giving rise to multiple vertebrate LDHs having occurred after vertebrates diverged from tunicates. The timing of these LDH duplications is consistent with data from a number of other gene families suggesting widespread gene duplication near the origin of vertebrates. With respect to the relationships among vertebrate LDHs, our data are not consistent with previous claims that Ldh-C represented the earliest divergence. However, the precise relationships among some of the main lineages of vertebrate LDHs were not resolved in our analyses.      

Phenotypic characterization of a genetically diverse panel of mice for behavioral despair and anxiety

Background

Animal models of human behavioral endophenotypes, such as the Tail Suspension Test (TST) and the Open Field assay (OF), have proven to be essential tools in revealing the genetics and mechanisms of psychiatric diseases. As in the human disorders they model, the measurements generated in these behavioral assays are significantly impacted by the genetic background of the animals tested. In order to better understand the strain-dependent phenotypic variability endemic to this type of work, and better inform future studies that rely on the data generated by these models, we phenotyped 33 inbred mouse strains for immobility in the TST, a mouse model of behavioral despair, and for activity in the OF, a model of general anxiety and locomotor activity.

Results

We identified significant strain-dependent differences in TST immobility, and in thigmotaxis and distance traveled in the OF. These results were replicable over multiple testing sessions and exhibited high heritability. We exploited the heritability of these behavioral traits by using in silico haplotype-based association mapping to identify candidate genes for regulating TST behavior. Two significant loci (-logp >7.0, gFWER adjusted p value <0.05) of approximately 300 kb each on MMU9 and MMU10 were identified. The MMU10 locus is syntenic to a major human depressive disorder QTL on human chromosome 12 and contains several genes that are expressed in brain regions associated with behavioral despair.

Conclusions

We report the results of phenotyping a large panel of inbred mouse strains for depression and anxiety-associated behaviors. These results show significant, heritable strain-specific differences in behavior, and should prove to be a valuable resource for the behavioral and genetics communities. Additionally, we used haplotype mapping to identify several loci that may contain genes that regulate behavioral despair.     

Cyclin B1 Overexpression Induces Cell Death Independent of Mitotic Arrest

Microtubule inhibitors are widely used in cancer chemotherapy. These drugs characteristically induce mitotic arrest and cell death but the mechanisms linking the two are not firmly established. One of the problems is that cancer cells vary widely in their sensitivity to these agents, and thus comparison of data from different systems is difficult. To alleviate this problem we sought to molecularly induce mitotic death and study its mechanisms, by expressing non-degradable cyclin B (R42A) in HeLa cells. However, this approach failed to induce significant mitotic arrest, Cdk1 activation, or phosphorylation of anti-apoptotic Bcl-2 proteins, all characteristics of cells treated with microtubule inhibitors. Furthermore, cyclin B1-R42A induced rapid cell death, and when expressed in synchronized cells, cell death occurred in G1 phase. Decreasing the plasmid concentration reduced transfection efficiency but restored mitotic arrest and eliminated non-specific death. These results show that inappropriate overexpression of cyclin B1 causes non-specific cell death and suggest caution in its use for the study of mitotic events.     

Gut microbiome-derived glycine lipids are diet-dependent modulators of hepatic injury and atherosclerosis

Oral and gut Bacteroidetes produce unique classes of serine-glycine lipodipeptides and glycine aminolipids that signal through host Toll-like receptor 2. These glycine lipids have also been detected in human arteries, but their effects on atherosclerosis are unknown. Here, we sought to investigate the bioactivity of bacterial glycine lipids in mouse models of atherosclerosis. Lipid 654 (L654), a serine-glycine lipodipeptide species, was first tested in a high-fat diet (HFD)-fed Ldlr^?/? model of atherosclerosis. Intraperitoneal administration of L654 over 7 weeks to HFD-fed Ldlr^?/? mice resulted in hypocholesterolemic effects and significantly attenuated the progression of atherosclerosis. We found that L654 also reduced liver inflammatory and extracellular matrix gene expression, which may be related to inhibition of macrophage activation as demonstrated in vivo by lower major histocompatibility complex class II gene expression and confirmed in cell experiments. In addition, L654 and other bacterial glycine lipids in feces, liver, and serum were markedly reduced alongside changes in Bacteroidetes relative abundance in HFD-fed mice. Finally, we tested the bioactivities of L654 and related lipid 567 in chow-fed Apoe^?/? mice, which displayed much higher fecal glycine lipids relative to HFD-fed Ldlr^?/? mice. Administration of L654 or lipid 567 for 7 weeks to these mice reduced the liver injury marker alanine aminotransferase, but other effects seen in Ldlr^?/? were not observed. Therefore, we conclude that conditions in which gut microbiome-derived glycine lipids are lost, such as HFD, may exacerbate the development of atherosclerosis and liver injury, whereas correction of such depletion may protect from these disorders.     

Evaluation of hypoglycemic therapeutics and nutritional supplementation for type 2 diabetes mellitus management: An insight on molecular approaches

Biotechnology Letters - This review aims to summarize the current management of type 2 diabetes principles, including oral hypoglycemic agents, types of insulin administration, diet maintenance,...     

Disruption in the autophagic process underlies the sensory neuropathy in dystonia musculorum mice

A homozygous mutation in the DST (dystonin) gene causes a newly identified lethal form of hereditary sensory and autonomic neuropathy in humans (HSAN-VI). DST loss of function similarly leads to sensory neuron degeneration and severe ataxia in dystonia musculorum (Dst^dt) mice. DST is involved in maintaining cytoskeletal integrity and intracellular transport. As autophagy is highly reliant upon stable microtubules and motor proteins, we assessed the influence of DST loss of function on autophagy using the Dst^dt-Tg4 mouse model. Electron microscopy (EM) revealed an accumulation of autophagosomes in sensory neurons from these mice. Furthermore, we demonstrated that the autophagic flux was impaired. Levels of LC3-II, a marker of autophagosomes, were elevated. Consequently, Dst^dt-Tg4 sensory neurons displayed impaired protein turnover of autophagosome substrate SQTSM1/p62 and of polyubiquitinated proteins. Interestingly, in a previously described Dst^dt-Tg4 mouse model that is partially rescued by neuronal specific expression of the DST-A2 isoform, autophagosomes, autolysosomes, and damaged organelles were reduced when compared to Dst^dt-Tg4 mutant mice. LC3-II, SQTSM1, polyubiquitinated proteins and autophagic flux were also restored to wild-type levels in the rescued mice. Finally, a significant decrease in DNAIC1 (dynein, axonemal, intermediate chain 1; the mouse ortholog of human DNAI1), a member of the DMC (dynein/dynactin motor complex), was noted in Dst^dt-Tg4 dorsal root ganglia and sensory neurons. Thus, DST-A2 loss of function perturbs late stages of autophagy, and dysfunctional autophagy at least partially underlies Dst^dt pathogenesis. We therefore conclude that the DST-A2 isoform normally facilitates autophagy within sensory neurons to maintain cellular homeostasis.     

Nectarless flowers: ecological correlates and evolutionary stability

In animal-pollinated flowers, the pollinators cannot detect the presence of nectar before entering flowers, and therefore flowers may cheat by not producing nectar. An earlier model suggested that a mixed strategy of producing nectarful and nectarless flowers would be evolutionarily stable. Here we compare nectarless flowers as a cheating strategy with three competing hypotheses namely "visit-more-flowers", "cross-pollination enhancement" and "better contact". We collected field data on 28 species of plants to test some of the differential predictions of the hypotheses. Nectarless flowers were detected in 24 out of 28 plant species. Correlations of percent nectarless flowers with floral and ecological variables support the cheater flower hypothesis. We further model the cost-benefits of cheating and show that an evolutionary stable ratio of nectarless to nectarful flowers can be reached. The equilibrium ratio is mainly decided by factors associated with pollinator density and pollinator learning.