Variability in development of tolerance to repeated injections of low doses of dl-amphetamine in rats

Male albino rats received injections of saline for 5 days before and 5 days after a series of 10 daily injections of dl-amphetamine, 1 or 5 mg/kg, sc. Core temperatures were measured every 30 min for 4 h after each injection and feeding activity (on a CRF operant schedule) every 30 min throughout. After amphetamine at either 0800 or 2000 h, a dose-related hyperthermia, stereotypic behavior, and an initial inhibition of feeding occurred. This anorexia decreased over the 4-h post injection period only in the evening-injected rats receiving 5 mg/kg. Mean body weights of all groups continued to increase during amphetamine administration. Mean 24-h food intake tended to remain below that in the control period and the hyperthermic response did not change significantly in any group. Initially on withdrawal from amphetamine all groups showed 'rebound' feeding. Taken with earlier reports, these results suggest that tolerance development to amphetamine-induced anorexia, hyperthermia, and stereotypic behavior occurs at different rates and is dependent upon frequency, route, dose, time, the amphetamine used, and whether the diet was restricted.     

Commentary on Gressel's review

Transgenic Research -     

Sex Differences in Detecting Sexual Infidelity

Despite the importance of extrapair copulation (EPC) in human evolution, almost nothing is known about the design features of EPC detection mechanisms. We tested for sex differences in EPC inference-making mechanisms in a sample of 203 young couples. Men made more accurate inferences (φ_men = 0.66, φ_women = 0.46), and the ratio of positive errors to negative errors was higher for men than for women (1.22 vs. 0.18). Since some may have been reluctant to admit EPC behavior, we modeled how underreporting could have influenced these results. These analyses indicated that it would take highly sex-differentiated levels of underreporting by subjects with trusting partners for there to be no real sex difference. Further analyses indicated that men may be less willing to harbor unresolved suspicions about their partners’ EPC behavior, which may explain the sex difference in accuracy. Finally, we estimated that women underreported their own EPC behavior (10%) more than men (0%).     

A novel method for the on-line analysis of fermentation broth using a sampling device,microcentrifuge and HPLC

Summary This paper describes a novel system for on-line sampling and analysis of whole broth from a fermenter. The system comprises a steam sterilisable sampling device, high speed microcentrifuge and HPLC. We present results characterising the separation efficiency of the microcentrifuge under different conditions, and illustrate the system with glucose and acetate data from an Escherichia coli fermentation using the system. The on-line measurements have been confirmed by off-line analysis.     

Female preference for the pheromone of males with low fluctuating asymmetry in the Japanese scorpionfly (Panorpa japonica: Mecoptera)

Fluctuating asymmetry (FA) is denned as small, random deviationsfrom perfect bilateral symmetry in a bilaterally symmetricalmorphological trait. The relationship between FA in forewinglength of males and the relative sexual attractiveness of theirpair-formation pheromones was studied experimentally in theJapanese scorpionfly, Panorpa japonica. This is the first studyof the role of FA in pheromonal communication systems, and oneof only a few studies on the relationship between FA and sexualselection. Collectively, the results of four interrelated experimentsreveal that females prefer the pheromone of males of relativelylow FA in forewing length. The experimental manipulation offorewing FA of males by cutting wing lengths did not influencetheir olfactory attractiveness to females. In this case, femaleschose the male with the lowest premanipulation FA. Thus, naturalwing length FA apparently is correlated with inherent differencesbetween males that influence the properties of sex attractantmales produce. Female preference for low-FA males may be adaptiveas a result of material and/or genetic benefits received byfemales.     

On-line recognition of CO2 exit gas profiles for operational harvesting time of intracellular enzyme products from S. cerevisiae

This paper concerns the recognition of significant events in the trends from CO₂ exit gas profiles of a S.cerevisiae fermentation. Distinct changes in the on-line monitored variable, CO₂ exit gas concentration, are used to recognise identifiable phases of glucose depletion, biomass formation and the onset of intracellular enzyme production. Process automation for the harvesting of some intracellular enzyme products from S. cerevisiae is considered using on-line recognition of CO₂ exit gas peaks.     

Pape in Panorpa scorpionflies and a general rape hypothesis

The adaptive significance of heterosexual rape is difficult to demonstrate because (1) female coyness is difficult to distinguish from apparent rape, and (2) male fitness must be enhanced by rape. Male Panorpa scorpionflies inseminate unwilling females by securing the female's wings in an abdominal clamp. Panorpa rapists gain fitness through avoidance of risks of predation by web-building spiders associated with the more typical male behaviours of feeding females a dead insect or salivary secretion during copulation. Males should be most strongly selected to rape in species in which males provide resources important for female reproduction. In such species, the strength of selection on males to rape should exceed the strength of selection on females to prevent rape.