Neocarzinostatin and auromomycin preferentially cleave simian virus 40 DNA and chromosomes at a number of discrete locations

Neocarzinostatin and auromomycin were shown to cleave simian virus 40 (SV40) DNA with preference for distinct regions of the viral genome. The positions cut by neocarzinostatin and auromomycin were similar, while micrococcal nuclease cleaved at positions other than those recognized by neocarzinostatin and auromomycin. Breaks were distributed throughout the viral genome and were not associated with any single type of genetic element. The limited number of locations in SV40 DNA that were preferentially cut by neocarzinostatin and auromomycin suggests that drug attack is directed by DNA structures other than the known trinucleotide sequence specificity of the drugs. Neocarzinostatin and auromomycin cut purified, cell-free, nuclear and intracellular chromosomal SV40 DNA at similar regions. The data indicate that there are regions in DNA that are hypersensitive to the drugs; the hypersensitivity may be determined by the microstructure of the DNA. The conformational change associated with the packing of the DNA into nucleosomes did not affect the microstructure of the sensitive region, nor did the shielding effect of nuclear proteins affect the drug's access to it. In addition, intracellular drug metabolism or other cellular factors did not alter the ability of drugs to interact at these sensitive regions.     

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.     

Assessing stimulus equivalence with a precursor to the relational evaluation procedure

Previous research has demonstrated that, after being trained on multiple match-to-sample (MTS) tasks (A-B, B-C), most human adults respond in accordance with symmetry (B-A, C-B) and equivalence (C-A) when measured with MTS tests and with a precursor to the Relational Evaluation Procedure (pREP). The latter procedure involves conditional go/no-go discrimination tasks, requiring subjects to press a bar during a 5s interval after the successive presentation of two same-class stimuli, and not to press after the presentation of two different-class stimuli (e.g. Ci -->Ai -->press, Ci -->Aj -->no press). The present study was an effort to replicate these findings. The study consisted of five experiments. Very few subjects evidenced pREP symmetry and equivalence unless they had (a) already demonstrated symmetry and equivalence in a MTS test before, or (b) received pREP pretraining with unrelated stimulus pairs and symmetry was tested before equivalence. Failures to show symmetry were always associated with pressing at or close to 50% of these trials. Failures to show equivalence were associated with pressing or not pressing on (almost) all trials. Current findings are similar to those obtained in equivalence studies involving MTS probes permitting the subjects not to respond to the designated comparisons.     

Functional interactions between Hsp90 and the co-chaperones Cns1 and Cpr7 in Saccharomyces cerevisiae

Hsp90 complexes contain a class of co-chaperones characterized by a tetratricopeptide repeat (TPR) domain, which mediates binding to a carboxyl-terminal EEVD region in Hsp90. Among Hsp90 TPR co-chaperones in Saccharomyces cerevisiae, only Cns1 is essential. The amino terminus of Cns1, which harbors the TPR domain, is sufficient for viability when overexpressed. In a screen for temperature-sensitive alleles of CNS1, we identified mutations resulting in substitutions of conserved residues in the TPR domain. Mutations in CNS1 disrupt in vitro and in vivo interaction with Hsp90 and reduce Hsp90 function, indicating that Cns1 is a bona fide co-chaperone. Genetic interactions between CNS1 and another Hsp90 co-chaperone, CPR7, suggest that the two co-chaperones share an essential role in the cell. Although both the TPR and the isomerase domains of the cyclophilin Cpr7 are required for viability of cns1 mutant cells, this requirement does not depend on the catalytic function of the isomerase domain. Instead, hydrophilic residues on the surface of this domain appear to be important for the common Cns1.Cpr7 function. Although both co-chaperones interact with Hsp90 primarily through the carboxyl terminus (EEVD), Cns1 and Cpr7 are mostly found in complexes distinct from Hsp90. EEVD is required for normal growth in cns1 mutant cells, demonstrating for the first time in vivo requirement for this conserved region of Hsp90. Overall, our findings reveal a considerable degree of complexity in the interactions not only between Hsp90 and its co-chaperones, but also among the co-chaperones themselves.