Tissue distribution of a plasmid DNA encoding Hsp65 gene is dependent on the dose administered through intramuscular delivery

In order to assess a new strategy of DNA vaccine for a more complete understanding of its action in immune response, it is important to determine the in vivo biodistribution fate and antigen expression. In previous studies, our group focused on the prophylactic and therapeutic use of a plasmid DNA encoding the Mycobacterium leprae 65-kDa heat shock protein (Hsp65) and achieved an efficient immune response induction as well as protection against virulent M. tuberculosis challenge. In the present study, we examined in vivo tissue distribution of naked DNA-Hsp65 vaccine, the Hsp65 message, genome integration and methylation status of plasmid DNA. The DNA-Hsp65 was detectable in several tissue types, indicating that DNA-Hsp65 disseminates widely throughout the body. The biodistribution was dose-dependent. In contrast, RT-PCR detected the Hsp65 message for at least 15 days in muscle or liver tissue from immunized mice. We also analyzed the methylation status and integration of the injected plasmid DNA into the host cellular genome. The bacterial methylation pattern persisted for at least 6 months, indicating that the plasmid DNA-Hsp65 does not replicate in mammalian tissue, and Southern blot analysis showed that plasmid DNA was not integrated. These results have important implications for the use of DNA-Hsp65 vaccine in a clinical setting and open new perspectives for DNA vaccines and new considerations about the inoculation site and delivery system.     

Induced lactic acid fermentation during the preservation stage of ripe olives from Hojiblanca cultivar

The influence of initial sodium chloride concentration (6 and 0%, w/v), acetic acid concentration (0.6, 0.3 and 0.0%, v/v), type of process (natural and inoculated), and storage system (anaerobic and aerobic) on the inducement of a lactic fermentation for the preservation stage of Hojiblanca cultivar ripe olives was investigated. The addition of 6% NaCl prevented colonization by lactic acid bacteria in all cases. A high level of acetic acid (0.6%) was effective in preserving olives for 2 months, although yeast growth was not inhibited for longer periods of storage. Natural growth of Lactobacillus plantarum did not occur. Inoculation with this micro-organism was effective only in the two treatments with tap water (with no NaCl) as the initial covering solution, although survival was reduced to a half of the added organisms when the initial pH was corrected with 0.3% acetic acid. In these two treatments pH quickly reached appropriate values (<4.0) for olive stabilization. Aerobic conditions led to low concentrations of carbon dioxide, without disturbing growth of lactic acid bacteria. Thus, the aerobic lactic acid fermentation, with tap water initially, was the most adequate preservation procedure for the storage of ripe olives prior to their oxidation treatment. Results of trials conducted on an industrial scale showed the same pattern and confirmed the viability of the new procedure.     

NOT EVERYTHING IS BLACK AND WHITE: COLOR AND BEHAVIORAL VARIATION REVEAL A CONTINUUM BETWEEN CRYPTIC AND APOSEMATIC STRATEGIES IN A POLYMORPHIC POISON FROG

Aposematism and crypsis are often viewed as two extremes of a continuum of visual conspicuousness to predators. Theory predicts that behavioral and coloration conspicuousness should vary in tandem along the conspicuousness spectrum for antipredator strategies to be effective. Here we used visual modeling of contrast and behavioral observations to examine the conspicuousness of four populations of the granular poison frog, Oophaga granulifera, which exhibits almost continuous variation in dorsal color. The patterns of geographic variation in color, visual contrast, and behavior support a gradient of overall conspicuousness along the distribution of O. granulifera. Red and green populations, at the extremes of the color distribution, differ in all elements of color, contrast, and behavior, strongly reflecting aposematic and cryptic strategies. However, there is no smooth cline in any elements of behavior or coloration between the two extremes. Instead populations of intermediate colors attain intermediate conspicuousness by displaying different combinations of aposematic and cryptic traits. We argue that coloration divergence among populations may be linked to the evolution of a gradient of strategies to balance the costs of detection by predators and the benefits of learned aversion.     

Allometry of reaching and contact structures in Kukulcania hibernalis (Araneae: Filistatidae)

Large part of the morphological diversity observed across taxa is attributed to the effect of sexual selection; and the static allometry of these structures vary largely from highly positive to negative, depending on their function, and position on the animal's body. In arthropods, information of how sexually selected contact and reaching male structures use during courtship scale on body size is scarce. We tested two complementary hypotheses: the reaching structure hypothesis and the contact‐function hypothesis, in the spider Kukulcania hibernalis. We used the length of the proximal segments of the male pedipalp to test the reaching structure hypothesis, and claw features to test the contact‐function hypothesis. Our results support both hypotheses. Small males have disproportionally longer pedipalps (highly negative allometry) than large males, increasing the probability of small‐bodied males to inseminate even large females. We also found that both distal contact and noncontact homologous structures scaled shallow (slope < 1) on body size, but allometry was significantly shallower for contact than for noncontact distal structures, providing support to the contact‐function hypothesis, and allowing teasing apart the effect of sexual selection on distal contact structures with dual functions.     

Role of the baroreceptor reflex in the early phases after removing the renal artery constriction in conscious renal hypertensive rats

Hemodynamic studies in unanesthetized rats with chronic one-kidney-Goldblatt hypertension showed a 25% increase in cardiac output and a 42% increase in peripheral resistance. Removal of renal artery constriction under either anesthesia and minor surgical trauma produced an immediate 20% drop in arterial pressure. At the end of the 6 observation period the pressure dropped 30% but still remained at a moderate hypertensive level. The hemodynamic measurement at that time suggested that the pressure drop was the result of a decrease in cardiac output. However, the data obtained 1 hour after removal of the constriction suggested that a vasodilating mechanism may also contribute to pressure normalization in the early phase of reversal of renal hypertension. In the sham-operated hypertensive rats the pressure remained unchanged, while the cardiac output dropped due to compensation by a proportional increase in peripheral resistance. In contrast, in the unclipped animals the same drop in cardiac output produced an equivalent fall in pressure because no change in peripheral resistance occurred. This was not due to an insufficiency of the baroreceptor reflex since bilateral splanchnicectomy performed at that time produced a striking hypotensive response, indicating an overactivity of the sympathetic system possibly due to the baroreceptor still reset to operate at a hypertensive level.