Enzymes of glycerolipid synthesis in small-intestinal mucosa of foetal and neonatal guinea pigs.

1. The activities of some enzymes of glycerolipid synthesis were measured in homogenates obtained from the intestinal scrapings of 62-66-day foetuses and 2- and 8-day-old guinea pigs. 2. The ratio of protein concentration/DNA concentration was significantly higher (P greater than 0.001) in homogenized tissue from the neonatal compared with the foetal guinea pigs. Enzyme activities were therefore expressed relative to both protein and to DNA. 3. The specific activities (relative to DNA) of palmitoyl-CoA synthetase, glycerol phosphate acyltransferase and phosphatidate phosphatase were higher in homogenized tissues from neonatal than in those from the foetal guinea pigs. These activities are probably involved more in cell proliferation than in the absorption and transport of triacylglycerol. Its activity was not significantly different in the foetal and neonatal guinea pigs when expressed relative to DNA but it was lower in the neonatal guinea pigs when expressed relative to protein. The entry of food into the intestine after birth is therefore not necessary for its activity.     

OESTROUS BEHAVIOUR, OVULATION AND THE FORMATION OF THE CORPUS LUTEUM IN THE AFRICAN ELEPHANT,

A female elephant was observed throughout most of oestrus, and was then shot. The cow was mated by many different bulls during the course of oestrus. Initially, there seemed to be little competition between bulls for the cow, but as oestrus wore on, fighting broke out amongst the bulls and one eventually appeared to establish mastery, driving the other bulls away. It was interesting that this master bull showed no discharge from his temporal glands.     

One-dimensional isoelectric focusing and immunoblotting of bovine major histocompatibility complex (BoLA) class I molecules and correlation with class I serology

One-dimensional isoelectric focusing followed by immunoblotting and development of the immunoblots with the monoclonal antibody HC-10, raised against denatured HLA class I heavy chains, was used to demonstrate biochemical variation in cattle MHC (BoLA) class I molecules. The bands obtained correlated well with BoLA-A specificities. Two or three bands were identified for the specificities w7, w8, w16, w18, w21, cph43 and cph49, whereas no bands were observed for the specificity w2. Two serologically indistinguishable subtypes of specificity w18 were identified.     

Influence of acoustics on the collective behaviour of a shoaling freshwater fish

1. Understanding how collective behaviour of animals is influenced by anthropogenic activity is important for their conservation in an increasingly urbanised world. River infrastructure, e.g. for transport and electricity generation, and associated construction and operation, produces sound that can disrupt ecological processes.
2. Adopting a reductionist manipulative experimental approach using Eurasian minnow (Phoxinus phoxinus) as a model shoaling species, we compared the response of individuals and groups of five fish to a broadband acoustic stimulus in a tank containing still water.
3. Four metrics were calculated 10 min immediately before (control–sound stimulus absent) and during the acoustic treatment: (1) swimming speed, (2) persistence of swim paths, (3) cohesion of the group, and (4) orientation of group members.
4. On presentation of the stimulus, groups exhibited a consistent escape response compared to individuals for which behaviour was more variable. Thereafter, individuals swam faster and their swim paths were less persistent than during the control; no difference was observed for groups. Conversely, group integrity became more cohesive and members were more likely to orient in a common direction during the treatment compared to the control.
5. This study provides insight into the importance of collective behaviour of fish in relation to antipredator-like response to anthropogenic noise. Short-term shifts in behaviour are context specific and depend on whether fish are members of a shoal or solitary. The results indicate the potential for negative impacts of unnatural sound on the ecology of shoaling species that inhabit engineered freshwater environments.