Diabetogenic diet-induced insulin resistance associates with lipid droplet proteins and adipose tissue secretome,but not with sexual dimorphic adipose tissue fat accumulation in Wistar rats

The role of sexual dimorphic adipose tissue fat accumulation in the development of insulin resistance is well known. However, whether vitamin A status and/or its metabolic pathway display any sex- or depot (visceral/subcutaneous)-specific pattern and have a role in sexual dimorphic adipose tissue development and insulin resistance are not completely understood. Therefore, to assess this, 5 weeks old Wistar male and female rats of eight from each sex were provided either control or diabetogenic (high fat, high sucrose) diet for 26 weeks. At the end, consumption of diabetogenic diet increased the visceral fat depots (p < 0.001) in the males and subcutaneous depot (p < 0.05) in the female rats, compared to their sex-matched controls. On the other hand, it caused adipocyte hypertrophy (p < 0.05) of visceral depot (retroperitoneal) in the females and subcutaneous depot of the male rats. Although vitamin A levels displayed sex- and depot-specific increase due to the consumption of diabetogenic diet, the expression of most of its metabolic pathway genes in adipose depots remained unaltered. However, the mRNA levels of some of lipid droplet proteins (perilipins) and adipose tissue secretory proteins (interleukins, lipocalin-2) did display sexual dimorphism. Nonetheless, the long-term feeding of diabetogenic diet impaired the insulin sensitivity, thus affected glucose clearance rate and muscle glucose-uptake in both the sexes of rats. In conclusion, the chronic consumption of diabetogenic diet caused insulin resistance in the male and female rats, but did not corroborate with sexual dimorphic adipose tissue fat accumulation or its vitamin A status.     

Glucose lowering effect of transgenic human insulin-like growth factor-I from rice: <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>studies

Background  

Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains.     

A comparative genomics study of genetic products potentially encoding ladderane lipid biosynthesis

Background  

The fatty acids of anaerobic ammonium oxidizing (anammox) bacteria contain linearly concatenated cyclobutane moieties, so far unique to biology. These moieties are under high ring strain and are synthesised by a presently unknown biosynthetic pathway.     

Tpl2 transduces CD40 and TNF signals that activate ERK and regulates IgE induction by CD40

Macrophages from Tpl2 knockout (Tpl2(-/-)) mice exhibit a defect in ERK activation by lipopolysaccharide (LPS). This impairs the nucleocytoplasmic transport of the tumor necrosis factor alpha (TNF-alpha) mRNA and prevents the induction of TNF-alpha by LPS. As a result, Tpl2(-/-) mice are resistant to LPS/D-galactosamine-induced shock. We demonstrate that Tpl2 is essential for ERK signals transduced by members of the TNF receptor superfamily, such as CD40 and the TNF receptor 1. Thus, ERK activation was impaired in Tpl2(-/-) B cells and macrophages stimulated with agonistic CD40 antibody or TNF-alpha, whereas the induction of other mitogen-activated protein kinases, such as JNK and p38, and the activation of NF-kappaB were unaffected. Tpl2 was recruited to a CD40/TRAF6 complex in response to CD40 stimulation. Moreover, TRAF6, which when overexpressed activates ERK, failed to do so in Tpl2(-/-) cells. The selective signaling defect resulting from the inactivation of Tpl2 allowed us to demonstrate that CD40-mediated ERK activation contributes to immunoglobulin production but is not essential for B-cell proliferation.     

Analysis of cardiac signals using spatial filling index and time-frequency domain

Background  

Analysis of heart rate variation (HRV) has become a popular noninvasive tool for assessing the activities of the autonomic nervous system (ANS). HRV analysis is based on the concept that fast fluctuations may specifically reflect changes of sympathetic and vagal activity. It shows that the structure generating the signal is not simply linear, but also involves nonlinear contributions. These signals are essentially non-stationary; may contain indicators of current disease, or even warnings about impending diseases. The indicators may be present at all times or may occur at random in the time scale. However, to study and pinpoint abnormalities in voluminous data collected over several hours is strenuous and time consuming.     

Epstein-Barr virus latent membrane protein 1 (LMP1) activates the phosphatidylinositol 3-kinase/Akt pathway to promote cell survival and induce actin filament remodeling

The Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) is an integral membrane protein that functions as a constitutively activated member of the tumor necrosis factor receptor family. Whereas LMP1 has been shown to activate the NF-kappaB and mitogen-activated protein kinase pathways, these effects alone are unable to account for the profound oncogenic properties of LMP1. Here we show that LMP1 can activate phosphatidylinositol 3-kinase (PI3K), a lipid kinase responsible for activating a diverse range of cellular processes in response to extracellular stimuli. LMP1 was found to stimulate PI3K activity inducing phosphorylation and subsequent activation of Akt, a downstream target of PI3K responsible for promoting cell survival. Treatment of LMP1-expressing cells with the PI3K inhibitor LY294002 resulted in decreased cell survival. The tumor necrosis factor receptor-associated factor-binding domain of LMP1 was found to be responsible for PI3K activation. The ability of LMP1 to induce actin stress-fiber formation, a Rho GTPase-mediated phenomenon, was also dependent on PI3K activation. These data implicate PI3K activation in many of the LMP1-induced phenotypic effects associated with transformation and suggests that this pathway contributes both to the oncogenicity of this molecule and its role in the establishment of persistent EBV infection.     

Evolution of transposable elements: an IS10 insertion increases fitness in Escherichia coli

Strains of Escherichia coli carrying Tn10, a transposon consisting of two IS10 insertion sequences flanking a segment encoding for a tetracycline-resistance determinant, gain a competitive advantage in chemostat cultures. All Tn10-bearing strains that increase in frequency during competition have a new IS10 insertion that is found in the same location in the genome of those strains. We mapped, by a gradient of transmission, the position of the new IS10 insertion. We examined 11 isolates whose IS10 insertion was deleted by recombinational crossing- over, and in all cases the competitive fitness of the isolates was decreased. These results show that the IS10-generated insertion increases fitness in chemostat cultures. We named the insertion fit::IS10 and suggest that transposable elements may speed the rate of evolution by promoting nonhomologous recombination between preexisting variations within a genome and thereby generating adaptive variation.      

Properties of the Glucose Transport System in Some Deep-Sea Bacteria

Many deep-sea bacteria are specifically adapted to flourish under the high hydrostatic pressures which exist in their natural environment. For better understanding of the physiology and biochemistry of these microorganisms, properties of the glucose transport systems in two barophilic isolates (PE-36, CNPT-3) and one psychrophilic marine bacterium (Vibrio marinus MP1) were studied. These bacteria use a phosphoenol-pyruvate:sugar phosphotransferase system (PTS) for glucose transport, similar to that found in many members of the Vibrionaceae and Enterobacteriaceae. The system was highly specific for glucose and its nonmetabolizable analog, methyl alpha-glucoside (a-MG), and exhibited little affinity for other sugars tested. The temperature optimum for glucose phosphorylation in vitro was approximately 20°C. Membrane-bound PTS components of deep-sea bacteria were capable of enzymatically cross-reacting with the soluble PTS enzymes of Salmonella typhimurium, indicating functional similarities between the PTS systems of these organisms. In CNPT-3 and V. marinus, increased pressure had an inhibitory effect on a-MG uptake, to the greatest extent in V. marinus. Relative to atmospheric pressure, increased pressure stimulated sugar uptake in the barophilic isolate PE-36 considerably. Increased hydrostatic pressure inhibited in vitro phosphoenolpyruvate-dependent a-MG phosphorylation catalyzed by crude extracts of V. marinus and PE-36 but enhanced this activity in crude extracts of the barophile CNPT-3. Both of the pressure-adapted barophilic bacteria were capable of a-MG uptake at higher pressures than was the nonbarophilic psychrophile, V. marinus.