Relationship of chin spot size to dominance in the black-chinned mouthbrooding cichlid fish (Sarotherodon melanotheron)

Aggressive interactions of male Sarotherodon melanotheron were studied to determine the communicative value of chin spot size in relation to dominance. In addition, the effects of residency and size on the aggressiveness of this fish were determined. Two-factor analysis of variance was used for frequencies of each modal action pattern for residency and size. Results show that residency played a major role in the outcome of an aggressive interaction, whereas size had little effect. Dominance of each experimental fish was calculated using Barlow & Ballin's (1976) dominance index. A chin spot ratio was obtained by dividing the chin spot area by the total surface area of the individual fish. Simple linear regression was conducted to determine if dominance and chin spot size were correlated and a positive linear relationship was found to exist between the two variables.     

The herpes simplex virus 1 origin binding protein: a DNA helicase.

A recombinant herpes simplex 1 origin binding protein, the product of the herpes UL9 gene, has been overexpressed in mammalian cells and purified to near homogeneity. The origin binding protein shows DNA-dependent nucleoside 5'-triphosphatase and DNA helicase activities in addition to its origin binding activity. The ability to hydrolyze nucleoside 5'-triphosphates is influenced strongly by the structure and sequence of the DNA cofactor. The properties of the recombinant origin binding protein are identical to those of the protein synthesized in herpes simplex 1-infected mammalian cells.     

Genetic structure and relationships among anadromous and landlocked populations of rainbow smelt, Osmerus mordax, Mitchill, as revealed by mtDNA restriction analysis

Larvae of anadromous rainbow smelt originating in various spawning tributaries are retained in the St Lawrence estuary. We proposed that these smelt represent one population genetically differentiated from adjacent populations characterized by geographically distinct larval retention areas. We also analysed four landlocked populations to evaluate the phylogenetic basis of dwarf and normal-sized phenotypes and their relation to an adromous smelt. A phylogenetic distinction was revealed between anadromous and landlocked smelt, with only one of the two mtDNA phylogenetic groups of anadromous fish observed among landlocked smelt. Significant geographical heterogeneity in the distribution of mtDNA genotypes was observed among landlocked smelt, suggesting that dwarfism in smelt may be polyphyletic in origin. St Lawrence smelt were genetically identical but distinct from adjacent populations, supporting the proposition that population genetic structure reflects the number of larval retention zones rather than spawning sites.     

Fatty Acid Oxidation and Ketogenesis by Astrocytes in Primary Culture

The oxidation of the fatty acids octanoate and palmitate to CO2 and the ketone bodies acetoacetate and D-(-)-3-hydroxybutyrate was examined in astrocytes that were prepared from cortex of 2-day-old rat brain and grown in primary culture to confluence. Accumulation of acetoacetate (by mass) in the culture medium of astrocytes incubated with octanoate (0.3-0.5 mM) was 50-90 nmol C2 units h-1 mg of protein-1. A similar rate was obtained using radiolabeled tracer methodology with [1-14C]octanoate as labeled substrate. The results from the radiolabeled tracer studies using [1-14C]- and [7-14C]octanoate and [1-14C]-, [13-14C]-, and [15-14C]palmitate indicated that a substantial proportion of the omega-terminal four-carbon unit of these fatty acids bypassed the beta-ketothiolase step of the beta-oxidation pathway and the 3-hydroxy-3-methylglutaryl (HMG)-CoA cycle of the classic ketogenic pathway. The [14C]acetoacetate formed from the 1-14C-labeled fatty acids, obligated to pass through the acetyl-CoA pool, contained 50% of the label at carbon 3 and 50% at carbon 1. By contrast, the [14C]acetoacetate formed from (omega-1)-labeled fatty acids contained 90% of the label at carbon 3 and 10% at carbon 1, whereas that formed from the (omega-3)-labeled fatty acid contained 20% of the label at carbon 3 and 80% at carbon 1. These results indicate that acetoacetate is primarily formed either by the action of 3-oxo-acid-CoA transferase (EC 2.8.3.5) or acetoacetyl-CoA deacylase (EC 3.1.2.11) or both on acetoacetyl-CoA and not by the action of the mitochondrial HMG-CoA cycle involving HMG-CoA lyase (EC 4.1.3.4), which was readily detected, and HMG-CoA synthase (EC 4.1.3.5), which was barely measurable.     

Mate choice in lekking sage grouse revisited: the roles of vocal display, female site fidelity, and copying

In lekking sage grouse (Centrocercus urophasianus), femalesexhibit relatively unanimous mate choice for particular males,but a satisfactory explanation for this unanimity has been elusive.We present analyses of mating distributions from two leks over4 years that provide evidence for female choice based on differencesin vocal display performance of males, the locations at whichhens mated in the previous year, and the choices of other females(copying). The unanimity of female choice varied markedly amongleks and years in correlation with changes in the mean numbersof hens that mated at the same time and hence the opportunityto copy. The results confirm that hens assess phenotypic traitsof males directly but also indicate that the secondary tacticsof site fidelity and copying are often important componentsof female choice. The occurrence of these secondary tacticshas three implications: the variance in mating success amonglek males will be a poor predictor of the intensity of sexualselection on specific traits; female preferences may generatemore clustered dispersions of displaying males than predictedby hotspot settlement models; and direct assessment of malesby females may be difficult or costly, a conclusion that supportsadaptive models of sexual selection over a nonadaptive Fisherianprocess. [Behav Ecol 1991;2:165–180]