Neurotransmitter mediation of morphine hypothermia in rats.

Subcutaneous (sc) injections of morphine (10 mg/kg) caused transient falls in body temperature of rats. The hypothermic responses to morphine were inhibited by the prior intracerebroventricular (icv) administration of methysergide or phentolamine. Methysergide treatment also prevented hypothermic responses to icv 5-hydroxytryptamine (5-HT), but not responses to icv norepinephrine or dopamine. Phentolamine inhibited responses to icv norepinephrine and dopamine, but not to 5-HT. Haloperidol, which inhibited responses to icv dopamine, did not alter the hypothermia induced by sc or icv morphine. The results indicate that both 5-HT and norepinephrine participate as central mediators of morphine-induced hypothermia.     

A quantitative measure of DNA curvature enabling the comparison of predicted structures

A growing body of data indicates that the equilibrium structures of some DNA fragments are curved and that curvature is sequence-directed. We describe a quantitative measure of DNA curvature that can be used for evaluating and comparing current proposed models for the molecular basis of DNA curvature. We demonstrate that this measure, in conjunction with any given prediction model, enables both the comparison of experimental data to predictions and the scanning of nucleotide sequence databases for potential curved regions.     

A program for computer-assisted scoring of Southern blots

SCORE, a program for computer-assisted scoring of Southern blots of clone DNA, retains the use of expert human judgment while taking over much of the drudgery of the scoring task. The primary functions of the program are to help make an aligned overlay of the fluorescence gel image and the autoradiogram blot image, to keep track of band and lane locations and to store the resulting data directly into a database. Use of SCORE has resulted in greatly increased efficiency and accuracy.     

Comparison of two introduction methods for African elephants (Loxodonta africana)

Managers must consider an animal's potential for aggression when they decide to change or form a captive social group formation. In this study we compared two introduction methods (termed “sequential” and “nonsequential” introductions) in African elephants to assess their effectiveness in managing aggression and minimizing stress. Both introduction methods included four phases: baseline, visual contact, limited tactile contact, and physical introduction. In the sequential introduction, these steps were followed sequentially, and empirical data were considered during decision‐making. In the nonsequential introduction, these steps were not followed sequentially, and decision‐making was based primarily on intuitive assessments by animal managers. Behavioral data and fecal corticoid concentrations were measured throughout both types of introduction. The behavior categories measured included active aggression, passive aggression, submissive behavior, undesirable/stress‐related behavior, and affiliative behavior. While the role of affiliative behavior was surprising, general behavior patterns were characterized by increases in behavior as animals progressed to the next phase of introduction regardless of introduction type. These increases then attenuated over time during each phase. Overall, less behavior was observed during the sequential introduction, as predicted. The data suggest that the sequential introduction managed aggression more effectively. Similar patterns were predicted for undesirable/stress‐related behavior and fecal corticoid concentration. Undesirable/stress‐related behavior was a poor predictor of observed behavior patterns. Although the patterns differed from those predicted, higher concentrations of fecal corticoids were measured during the nonsequential introduction and correlated significantly only with submissive behavior. While more investigation is warranted, the data indicate that the nonsequential introduction brought about an increased physiological response. Overall, the sequential introduction method appeared to manage aggression and stress better than the nonsequential technique. Every introduction is subject to factors that can influence success, such as staff experience, the design of the facility, and the animals' social histories. It is hoped that the rigorous sequential protocol will be a useful tool in the animal manager's “toolbox” for planning and implementing introductions. Applications of this introduction method are also discussed. Zoo Biol 23:109–126, 2004. © 2004 Wiley‐Liss, Inc.     

A substance from Heliothis virescens larvae stimulating larviposition by females of the tachinid,Archytas marmoratus

A chemical present in faeces, haemolymph, and whole bodies of larvae of Heliothis virescens stimulates females of the tachinid Archytas marmoratus to deposit maggots in the vicinity of the host. The larvipositional stimulant is soluble in water and in 0·1 N HCl and 0·1 N acetic acid and is insoluble in apolar solvents. Considerable activity is present in 0·1 N HCl extracts of acetone powders of whole H. virescens larvae. Larvipositional activity is destroyed by alkaline solutions. The activity of acidic extracts is greater than that of aqueous extracts when extracts are stored at 2°C for several days; however, extraction of the larvipositional stimulant is not necessarily more efficient with acidic extracts because there is no difference in the activity of the residues remaining after water and acid extraction. Thus, low pH appears to retard the decomposition of the larvipositional stimulant. Gel filtration, chromatography, and membrane filtration demonstrated that the compound has a molecular weight of 30,000 ± 5000. Rapid loss of activity during incubation with a proteinase (pepsin) indicates that the chemical is a protein. Larvipositional activity is present in larvae, pupae, pharate adults, and newly emerged adults of H. virescens. Most species of noctuids tested are highly active, and some activity is present in pyralid larvae. Very little or no activity is present in larvae of the beetle, Anthonomus grandis, or in Apis mellifera.