Unequivocal determination of sire allele origin for multiallelic microsatellites when only the sire and progeny are genotyped

The effect of a segregating economic trait locus (ETL) can be detected with the aid of a linked genetic marker, if specific alleles of each locus are in association among the individuals genotyped for the genetic marker. For dairy cattle this can be achieved by application of the ‘granddaughter design’. If only the sires and their sons are genotyped for the genetic markers, then the allele origin of sons having the same genotypes as their sires cannot be determined. Seven sires and 101 sons were genotyped for five microsatellites. The mean frequency of heterozygous sires was 77%. The mean number of alleles per locus was 8.2. Frequency of informative sons per locus ranged from 60% to 80% with a mean of 72%. With highly polymorphic microsatellites, at least 60% more grandsire families can be included in the analysis, and the number of sons assayed can be reduced by 40%, as compared to diallelic markers.     

Intraspecific variation in reproductive physiology and egg quality in the European Starling Sturnus vulgaris

Egg mass shows large intraspecific variation in birds and is repeatable within individuals. The mechanisms underlying this variation are unknown. We hypothesized that measures of egg quality (the mass of yolk protein, yolk lipid, and albumen protein) would be positively correlated with the plasma pools of the yolk precursor vitellogenin, and the masses of the oviduct, metabolic machinery (liver, heart, lungs, kidneys, gizzard, small intestine and pancreas), and endogenous stores of protein and lipid. We tested these predictions in European Starlings Sturnus vulgaris collected at the peak of egg production effort. In contrast to our predictions, both yolk protein and yolk lipid were negatively correlated with plasma vitellogenin levels. Albumen protein was positively related to oviduct mass, but other aspects of body composition failed to explain variation in egg quality. Hence, while we observed correlations between egg composition and peripheral systems (circulating precursor pools and the oviduct), we found no evidence that egg quality is determined by more general processes, i.e., the supply and processing of nutrients.     

Macrophage activation for antileishmanial defense by an apparently novel mechanism

Activation of macrophages by lymphokines (including interferon-gamma; IFN-gamma) is presently considered to be a major host defense mechanism against a number of intracellular microorganisms. In a series of earlier studies that made use of mice undergoing spontaneous resolution of footpad infections with Leishmania major, we obtained evidence suggesting that a subpopulation of Leishmania-sensitized lymph node T lymphocytes could activate antimicrobial effects in Leishmania-infected macrophages by an apparently lymphokine-independent mechanism. These effector lymphocytes are not cytotoxic to host cells, and their effects are antigen specific and genetically restricted. To more rigorously investigate this apparently novel mechanism of macrophage activation, we examined the effect of blocking lymphokine production with cyclosporin A (CSA) on the capacity of these effector lymphocytes to exert macrophage activating function. Although CSA blocked lymphokines that activate antileishmanial effects, it did not inhibit the antimicrobial capacity of the effector lymphocytes. We also confirmed that IFN-gamma is the major macrophage-activating lymphokine that induces antileishmanial effects; treatment of lymphokine-containing supernatants with anti-IFN-gamma antibody markedly reduced their antimicrobial effects. In contrast, treatment of effector lymphocytes with this antibody failed to reduce their macrophage-activating capacity. We conclude that there exists an apparently novel macrophage-activating mechanism for antimicrobial defense that is independent of soluble lymphokine mediators.     

Analysis of the Escherichia coli glycogen gene cluster suggests that catabolic enzymes are encoded among the biosynthetic genes

The nucleotide sequences of the Escherichia coli genome between the glycogen biosynthetic genes glgB and glgC, and 1170 bp of DNA which follows glgA have been determined. The region between glgB and glgC contains an open reading frame (ORF) of 1521 bp which we call glgX. This ORF is capable of coding for an M_r 56 684 protein. The deduced amino acid (aa) sequence for the putative product shows significant similarity to the E. coli glycogen branching enzyme, and to several different glucan hydrolases and transferases. The regions of sequence similarity include residues which have been reported to be involved in substrate binding and catalysis by taka-amylase. This suggests that the proposed product may catalyze hydrolysis or glycosyltransferase reactions. The cloned region which follows glgA contains an incomplete ORF (1149 bp), glgY, which appears to encode 383 aa of the N terminus of glycogen phosphorylase, based upon sequence similarity with the enzyme from rabbit muscle (47% identical aa residues) and with maltodextrin phosphorylase from E. coli (37% identical aa residues). Results suggest that neither ORF is required for glycogen biosynthesis. The localization of glycogen biosynthetic and degradative genes together in a cluster may facilitate the regulation of these systems in vivo.