Assessing human impact despite uncertainty:viability of the northern spotted owl metapopulation in the northwestern USA

We demonstrate the effect of uncertainty (resulting from lack of information or measurement error) on the assessment of human impact, with an analysis of the viability of the northern spotted owl throughout its range in the United States. We developed a spatially-explicit, stage-structured, stochastic metapopulation model of the northern spotted owl throughout its range in the United States. We evaluated the viability of the metapopulation using measures such as risk of decline and time to extinction. We incorporated uncertainty in the form of parameter ranges, and used them to estimate upper and lower bounds on the estimated viability of the species. We analysed the effect of this type of uncertainty on the assessment of human impact by comparing the species' viability under current conditions and under an assumed loss of spotted owl habitat in the next 100 years. The ranges of parameters were quite large and resulted in a wide range of risks of extinction. Despite this uncertainty, the results were sensitive to parameters related to habitat loss: under all assumptions and combinations of parameters, the model predicted that habitat loss results in substantially higher risks of metapopulation decline. This result demonstrated that even with relatively large uncertainties, risk-based model results can be used to assess human impact reliably.     

Binding of lead ion to bovine serum albumin studied by ion selective electrode

The binding of Pb2+ to bovine serum albumin (BSA) at neutral pH was studied using lead ion selective electrode. The binding data was treated according to Scatchard Equation. The number of binding classes and the number of binding sites, intrinsic dissociation constants and stepwise binding constants for each class were determined. Two binding classes were found. Four binding sites in the first class and five binding sites in the second class were determined. Binding in the first class was stronger than in the second. Similar binding studies were carried out with heat treated BSA. It was found that not only the number of binding sites but also the strength of binding increases upon heat treatment.     

Stomatopods (Crustacea: Hoplocarida) from the Gulf of Tehuantepec, Mexico

A total of 1,173 specimens of Stomatopoda were captured in 27 localities at different depths (20 to 73 m) during three oceanographic cruises in the Mexican Pacific along the continental shelf of the states of Oaxaca and Chiapas. Seven species were identified of the families Eurysquillidae, Lysiosquillidae and Squillidae. Squilla hancocki and Squilla parva were the most abundant species and the most frequently found together. The relationships between total length and carapace length were obtained for these species, which show that males of S. hancocki have a longer carapace length than females having the same total length, whereas for S. parva the opposite occurs. Larger sizes than previously reported were obtained for Lysiosquilla panamica and Squilla mantoidea. Squilla bigelowi was recorded for the first time in the Gulf of Tehuantepec. All the species were found in the intermediate platform (25-60 m); E. veleronis, S. hancocki and S. parva extended their distributions to the external platform (60-120 m), and S. hancocki and S. parva reached the circalittoral zone (10-25 m).     

Vasoactive intestinal peptide inhibits degranulation and changes granular content of mast cells: a potential therapeutic strategy in controlling septic shock

Vasoactive intestinal peptide (VIP) has potent protective activity against sepsis and increases the survival rate of septic rats and mice. The present study was planned to evaluate the effect of VIP on mast cell activity, histamine and methylhistamine levels and oxidative stress in the liver and kidneys of septic rats. The effect of VIP was compared to that of nitric oxide synthesis inhibition, previously tested extensively in septic shock models, with doubtful benefit. The present study showed that endotoxic shock did not lead to oxidative stress in either liver or kidney of the rats. On the other hand, mast cells, based on their location, displayed functional heterogeneity to the septic insults. VIP possibly modulated the specific reactions of the tissues to mediators released from mast cells during septic shock. The most prominent effect of VIP as compared to nitric oxide synthesis inhibition was related to mast cells. In conclusion, the prevention of mast cell reactivity by VIP could be a potential therapeutic strategy in controlling septic shock.