Adrenalectomy alters the sensitivity of the central nervous system melanocortin system

Removal of adrenal steroids by adrenalectomy (ADX) reduces food intake and body weight in rodents and prevents excessive weight gain in many genetic and dietary models of obesity. Thus, glucocorticoids appear to play a key role to promote positive energy balance in normal and pathological conditions. By comparison, central nervous system melanocortin signaling provides critical inhibitory tone to regulate energy balance. The present experiments sought to test whether glucocorticoids influence energy balance by altering the sensitivity to melanocortin receptor ligands. Because melanocortin-producing neurons are hypothesized to be downstream of leptin in a key weight-reducing circuit, we tested rats for their sensitivity to leptin and confirmed reports that the hypophagic response to third ventricular (i3vt) leptin is increased in ADX rats and is normalized by glucocorticoid replacement. Next we tested rats for their sensitivity to the melanocortin agonist melanotan II and found that, as for leptin, ADX enhanced the hypophagic response via a glucocorticoid-dependent mechanism. The central nervous system melanocortin system is unique in that it includes the endogenous melanocortin receptor antagonist, AgRP. The orexigenic effect of i3vt AgRP was absent in ADX rats and restored by glucocorticoid replacement. We conclude that the potent weight-reducing effects of ADX likely involve heightened responsiveness to melanocortin receptor stimulation

FIDEL—a retrovirus-like retrotransposon and its distinct evolutionary histories in the A- and B-genome components of cultivated peanut

In this paper, we describe a Ty3-gypsy retrotransposon from allotetraploid peanut (Arachis hypogaea) and its putative diploid ancestors Arachis duranensis (A-genome) and Arachis ipaënsis (B-genome). The consensus sequence is 11,223 bp. The element, named FIDEL (Fairly long Inter-Dispersed Euchromatic LTR retrotransposon), is more frequent in the A- than in the B-genome, with copy numbers of about 3,000 (±950, A. duranensis), 820 (±480, A. ipaënsis), and 3,900 (±1,500, A. hypogaea) per haploid genome. Phylogenetic analysis of reverse transcriptase sequences showed distinct evolution of FIDEL in the ancestor species. Fluorescent in situ hybridization revealed disperse distribution in euchromatin and absence from centromeres, telomeric regions, and the nucleolar organizer region. Using paired sequences from bacterial artificial chromosomes, we showed that elements appear less likely to insert near conserved ancestral genes than near the fast evolving disease resistance gene homologs. Within the Ty3-gypsy elements, FIDEL is most closely related with the Athila/Calypso group of retrovirus-like retrotransposons. Putative transmembrane domains were identified, supporting the presence of a vestigial envelope gene. The results emphasize the importance of FIDEL in the evolution and divergence of different Arachis genomes and also may serve as an example of the role of retrotransposons in the evolution of legume genomes in general

A physical map of Brassica oleracea shows complexity of chromosomal changes following recursive paleopolyploidizations

<p>Abstract</p> <p>Background</p> <p>Evolution of the Brassica species has been recursively affected by polyploidy events, and comparison to their relative, <it>Arabidopsis thaliana</it>, provides means to explore their genomic complexity.</p> <p>Results</p> <p>A genome-wide physical map of a rapid-cycling strain of <it>B. oleracea </it>was constructed by integrating high-information-content fingerprinting (HICF) of Bacterial Artificial Chromosome (BAC) clones with hybridization to sequence-tagged probes. Using 2907 contigs of two or more BACs, we performed several lines of comparative genomic analysis. Interspecific DNA synteny is much better preserved in euchromatin than heterochromatin, showing the qualitative difference in evolution of these respective genomic domains. About 67% of contigs can be aligned to the Arabidopsis genome, with 96.5% corresponding to euchromatic regions, and 3.5% (shown to contain repetitive sequences) to pericentromeric regions. Overgo probe hybridization data showed that contigs aligned to Arabidopsis euchromatin contain ~80% of low-copy-number genes, while genes with high copy number are much more frequently associated with pericentromeric regions. We identified 39 interchromosomal breakpoints during the diversification of <it>B. oleracea </it>and <it>Arabidopsis thaliana</it>, a relatively high level of genomic change since their divergence. Comparison of the <it>B. oleracea </it>physical map with Arabidopsis and other available eudicot genomes showed appreciable 'shadowing' produced by more ancient polyploidies, resulting in a web of relatedness among contigs which increased genomic complexity.</p> <p>Conclusions</p> <p>A high-resolution genetically-anchored physical map sheds light on Brassica genome organization and advances positional cloning of specific genes, and may help to validate genome sequence assembly and alignment to chromosomes.</p> <p>All the physical mapping data is freely shared at a WebFPC site (<url>http://lulu.pgml.uga.edu/fpc/WebAGCoL/brassica/WebFPC/</url>; Temporarily password-protected: account: pgml; password: 123qwe123.</p

Sensing the fuels: glucose and lipid signaling in the CNS controlling energy homeostasis

The central nervous system (CNS) is capable of gathering information on the body’s nutritional state and it implements appropriate behavioral and metabolic responses to changes in fuel availability. This feedback signaling of peripheral tissues ensures the maintenance of energy homeostasis. The hypothalamus is a primary site of convergence and integration for these nutrient-related feedback signals, which include central and peripheral neuronal inputs as well as hormonal signals. Increasing evidence indicates that glucose and lipids are detected by specialized fuel-sensing neurons that are integrated in these hypothalamic neuronal circuits. The purpose of this review is to outline the current understanding of fuel-sensing mechanisms in the hypothalamus, to integrate the recent findings in this field, and to address the potential role of dysregulation in these pathways in the development of obesity and type 2 diabetes mellitus

ESTs in Plants: Where Are We Heading?

Expressed sequence tags (ESTs) are the most important resources for transcriptome exploration. Next-generation sequencing technologies have been generating gigabytes of genetic codes representing genes, partial and whole genomes most of which are EST datasets. Niche of EST in plants for breeding, regulation of gene expression through miRNA studies, and their application for adapting to climatic changes are discussed. Some of the recent tools for analysis of EST exclusive to plants are listed out. Systems biology though in its infancy in plants has influenced EST mapping for unraveling gene regulatory circuits, which is illustrated with a few significant examples. This review throws a glance at the evolving role of ESTs in plants

Evolution of extensively drug-resistant tuberculosis over four decades: whole genome sequencing and dating analysis of Mycobacterium tuberculosis isolates from KwaZulu-Natal.

CAPRISA, 2015.Abstract available in pdf

Cerebrospinal fluid and plasma leptin measurements: covariability with dopamine and cortisol in fasting humans.

Leptin (OB protein) is an important signal in the regulation of energy balance. Leptin levels correlate with adiposity, but also decrease acutely with caloric restriction and increase with refeeding. The brain is an established critical site of leptin function, yet little is known about leptin concentrations in the central nervous system relative to plasma levels, psychiatric diagnoses, and other endocrine parameters. Therefore, using a novel ultrasensitive leptin assay, we explored relationships of human plasma and cerebrospinal fluid (CSF) leptin levels to body mass index, smoking, posttraumatic stress disorder diagnosis, and levels of dopamine, monoamine metabolites, beta-lipotropin, glucocorticoid, and thyroid and cytokine hormones. A strong linear relation between CSF and plasma leptin levels in the am (r = 0.63; P &lt; 0.002) and afternoon (r = 0.90; P &lt; 0.0001) was revealed. CSF and plasma leptin concentrations decreased during a 12- to 20-h period of fasting. A strong association was found between plasma leptin and CSF dopamine levels (r = 0.74; P &lt; 0.01) as well as between CSF leptin levels and urinary free cortisol (r = 0.73; P &lt; 0.01). Both of these parameters covaried with leptin independently of adiposity, as estimated by body mass index. Implications for leptin transport, regulation, and its potential role in therapeutic strategies for obesity and diabetes are discussed