Repeated oral administration of capsaicin increases anxiety-like behaviours with prolonged stress-response in rats

This study was conducted to examine the psycho-emotional effects of repeated oral exposure to capsaicin, the principal active component of chili peppers. Each rat received 1 mL of 0.02% capsaicin into its oral cavity daily, and was subjected to behavioural tests following 10 daily administrations of capsaicin. Stereotypy counts and rostral grooming were significantly increased, and caudal grooming decreased, in capsaicin-treated rats during the ambulatory activity test. In elevated plus maze test, not only the time spent in open arms but also the percent arm entry into open arms was reduced in capsaicin-treated rats compared with control rats. In forced swim test, although swimming duration was decreased, struggling increased in the capsaicin group, immobility duration did not differ between the groups. Repeated oral capsaicin did not affect the basal levels of plasma corticosterone; however, the stress-induced elevation of plasma corticosterone was prolonged in capsaicin treated rats. Oral capsaicin exposure significantly increased c-Fos expression not only in the nucleus tractus of solitarius but also in the paraventricular nucleus. Results suggest that repeated oral exposure to capsaicin increases anxiety-like behaviours in rats, and dysfunction of the hypothalamic-pituitary-adrenal axis may play a role in its pathophysiology.     

Effect of weight loss and exercise on angiogenic factors in the circulation and in adipose tissue in obese subjects

Background:

Vascular growth is a prerequisite for adipose tissue (AT) development and expansion. Some AT cytokines and hormones have effects on vascular development, like vascular endothelial growth factor (VEGF‐A), angiopoietin (ANG‐1), ANG‐2 and angiopoietin‐like protein‐4 (ANGPTL‐4).

Methods:

In this study, the independent and combined effects of diet‐induced weight loss and exercise on AT gene expression and proteins levels of those angiogenic factors were investigated. Seventy‐nine obese males and females were randomized to: 1. Exercise‐only (EXO; 12‐weeks exercise without diet‐restriction), 2. Hypocaloric diet (DIO; 8‐weeks very low energy diet (VLED) + 4‐weeks weight maintenance diet) and 3. Hypocaloric diet and exercise (DEX; 8‐weeks VLED + 4‐weeks weight maintenance diet combined with exercise throughout the 12 weeks). Blood samples and fat biopsies were taken before and after the intervention.

Results:

Weight loss was 3.5 kg in the EXO group and 12.3 kg in the DIO and DEX groups. VEGF‐A protein was non‐significantly reduced in the weight loss groups. ANG‐1 protein levels were significantly reduced 22‐25% after all three interventions (P < 0.01). The ANG‐1/ANG‐2 ratio was also decreased in all three groups (P < 0.05) by 27‐38%. ANGPTL‐4 was increased in the EXO group (15%, P < 0.05) and 9% (P < 0.05) in the DIO group. VEGF‐A, ANG‐1, and ANGPTL‐4 were all expressed in human AT, but only ANGPTL‐4 was influenced by the interventions.

Conclusions:

Our data show that serum VEGF‐A, ANG‐1, ANG‐2, and ANGPTL‐4 levels are influenced by weight changes, indicating the involvement of these factors in the obese state. Moreover, it was found that weight loss generally was associated with a reduced angiogenic activity in the circulation.     

Immunological activity of lipopolysaccharide of Helicobacter pylori on human peripheral mononuclear blood cells in comparison to lipopolysaccharides of other intestinal bacteria

Abstract Lipopolysaccharide of Helicobacter pylori was tested for its mitogenicity and for its ability to stimulate cytokine release in human peripheral blood mononuclear cells (PBMC) of healthy and H. pylori -infected blood donors. Mitogenicity in PBMC induced by H. pylori LPS was similar to that induced by Campylobacter jejuni lipopolysaccharide, but lower than that induced by Escherichia coli lipopolysaccharide in the H. pylori negative blood donor group. Furthermore, H. pylori LPS was able to induce tumour necrosis factor (TNF) interleukin 1 (IL-1) and interleukin 6 (IL-6) secretion of PBMC. Compared with the ability of C. jejuni and E. coli lipopolysaccharides to stimulate cytokine release, H. pylori lipopolysaccharide induced a significantly lower TNF and IL-1 secretion of PBMC than the other tested bacterial lipopolysaccharides. Similar amounts of IL-6 release were obtained by stimulation of PBMC with H. pylori and C. jejuni lipopolysaccharides, whereas a higher IL-6 release was measured by stimulation with E. coli lipopolysaccharide. The results of this study suggest that H. pylori lipopolysaccharide has a lower immunological activity than lipopolysaccharides of other intestinal bacteria. This is probably due to its unusual acylation and phosphorylation pattern of lipid A.     

Structural and functional characterization of the Zn(II) site in dimethylargininase-1 (DDAH-1) from bovine brain. Zn(II) release activates DDAH-1

L-N(omega),N(omega)-dimethylarginine dimethylaminohydrolase-1 (DDAH-1) is a Zn(II)-containing enzyme that, through hydrolysis of side-chain methylated l-arginines, regulates the activity of nitric-oxide synthase. Herein we report the structural and functional properties of the Zn(II)-binding site in DDAH-1 from bovine brain. Activity measurements of the native and metal-free enzyme have revealed that the endogenously bound Zn(II) inhibits the enzyme. Native DDAH-1 could be fully or partially activated using various concentrations of phosphate, imidazole, histidine, and histamine, a process that is paralleled by the release of Zn(II). The slow activation of the enzyme by the bulky complexing agents EDTA and 1,10-phenantroline suggests that the Zn(II)-binding site is partially buried in the protein structure. The apparent Zn(II)-dissociation constant of 4.2 nm, determined by 19F NMR using the chelator 5F-BAPTA (1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid), lies in the range of intracellular free Zn(II) concentrations. These results suggest a regulatory role for the Zn(II)-binding site. The coordination environment of the Zn(II) in DDAH-1 has been examined by Zn K-edge x-ray absorption spectroscopy. The extended x-ray absorption fine structure observed is consistent with Zn(II) being coordinated by 2 S and 2 N (or O) atoms. The biological implications of these findings are discussed.     

Preparation of nitrophorin 7(Δ1–3) from Rhodnius prolixus without start–methionine using recombinant expression in Escherichia coli

The heterologous recombinant expression of proteins in Escherichia coli without start–methionine is a common problem. The nitrophorin 7 heme properties and function strongly depend on the accurate N-terminal amino acid sequence. Leading protein expression into the periplasm by fusion with the leader peptide pelB yields functional protein; however, the folded protein sticks to the cell debris. Therefore, the periplasmic fraction was dissolved in guanidinium chloride and folded by a drop-in method. Separation from impurities including residual pelB–nitrophorin 7 required establishing an unconventional chromatographic technique using calcium-loaded Chelating Sepharose as cation exchanger and elution by a linear CaCl₂ gradient.     

Effect of chronic treatment with Rosiglitazone on Leydig cell steroidogenesis in rats: <Emphasis Type="Italic">In vivo</Emphasis> and <Emphasis Type="Italic">ex vivo</Emphasis> studies

Background  

The present study was designed to examine the effect of chronic treatment with rosiglitazone - thiazolidinedione used in the treatment of type 2 diabetes mellitus for its insulin sensitizing effects - on the Leydig cell steroidogenic capacity and expression of the steroidogenic acute regulatory protein (StAR) and cholesterol side-chain cleavage enzyme (P450scc) in normal adult rats.     

Effect of water stress on proline accumulation of genetically modified potatoes (Solanum tuberosum L.) generating fructans

This study aimed to investigate the effect of water stress on the accumulation of proline in the leaves of transgenic potato lines generating fructans. The results of the series of bifactorial experiments in 2002 and 2003 indicated an increase of the proline level in leaves of all potato lines examined under water deficit. In addition, an increase in proline concentration during plant development was observed. The proline content was related to leaf water potential and relative water content (RWC), which indicates that proline could be involved in osmoregulation of potato plants under the experimental conditions. Surprisingly, under water deficit, the proline level was lowest in most of the transgenic SST/FFT-lines, which generate fructan molecules with a high degree of polymerization. Therefore, a pleiotropic effect can not be excluded as the reason for the divergence in behavior of these transgenic lines. The present results suggest that the modification of carbohydrate metabolism, especially the high content of soluble carbohydrates, may affect water stress-induced proline accumulation.     

Insertion of an h-bonding residue into the distal pocket of the ferriheme protein nitrophorin 4: effect on nitriteiron coordination and nitrite disproportionation

Heme proteins are important entities for the metabolism of nitrite. Inspection of the structural features of the reported hemoprotein?nitrite crystal structures reveals that, except for nitrophorin 4 (NP4), H-bonding to the nitrite ligand is accomplished via histidine or arginine residues. These H-bonds probably play an important role for the nitrite coordination and/or reactivities. In nitrophorins, which catalyze the nitrite disproportionation reaction, such a residue is missing. Here, we report on the L130R mutant of the NP isoprotein NP4 that provides the Arg130 residue as part of the flexible G?H loop as a potential H-bonding residue in the distal heme pocket. Similar to the wild-type protein, nitrite remains N-bonded in the crystal structure of NP4(L130R). However, spectroscopic investigations show that, in solution, a second ligand-rotational orientation exists, which is in fast-exchange equilibrium with the normal, parallel ligand orientation. Moreover, the nitrite disproportionation is inhibited in NP4(L130R). Comparison with another, also less active mutant NP4(D30N) suggests that the displacement of H(2) O molecules from the heme cavity prevents the proton donation pathway through Asp30.     

First detection, isolation and molecular characterization of infectious salmon anaemia virus associated with clinical disease in farmed Atlantic salmon (Salmo salar) in Chile

Background  

Several forms of progressive retinal atrophy (PRA) segregate in more than 100 breeds of dog with each PRA segregating in one or a few breeds. This breed specificity may be accounted for by founder effects and genetic drift, which have reduced the genetic heterogeneity of each breed, thereby facilitating the identification of causal mutations. We report here a new form of PRA segregating in the Border Collie breed. The clinical signs, including the loss of night vision and a progressive loss of day vision, resulting in complete blindness, occur at the age of three to four years and may be detected earlier through systematic ocular fundus examination and electroretinography (ERG).     

三氧化二砷对食管癌细胞增殖和热休克蛋白70表达的影响

目的：研究三氧化二砷（As2O3）对食管癌细胞增殖和热休克蛋白70（HSP70）表达的影响。方法：通过相差显微镜、流式细胞术、免疫细胞化学染色和免疫印迹分析等方法观察As2O3对人食管癌细胞株EC1的作用效果和作用机制。结果：与对照组相比,经2μmol/L和5μmol/Las2O3作用的细胞出现明显的生长抑制,G2/M期细胞比例增加;2μmol/Las2O3作用48h后经Ecl细胞HSP70（heat shock protein70）及HSC70(heat shock cognate protein70)表达均增加。结论：As2O3诱导食管癌细胞G2/M期阻滞抑制细胞增殖和生长;HSP70的升高是细胞对As2O3作用后出现的应激反应,并与细胞周期阻滞相关。