Preimplantation screening for transgenesis using an embryonic specific promoter and green fluorescent protein

We report enrichment in the efficiency of generating mice transgenic for expression of a human protein in their milk using GFP-mediated preimplantation screening. The transgene array consisted of a functional gene (human alpha-1 antitrypsin under the control of the ovine BLG promoter) linked 5' to a reporter gene (GFP under the control of the murine Oct-4 promoter). GFP expression was detected in blastocysts by fluorescence microscopy and green and nongreen embryos were transferred to recipients in separate groups. In the first experiment, of seven pups that resulted from the transfer of blastocysts expressing GFP, five (71%) were transgenic. The experiment was repeated and of 12 pups that resulted from transfer of GFP-expressing blastocysts, 11 were transgenic (92%). The presence of the reporter cassette used for preimplantation screening did not affect the expression level of alpha-1-antitrypsin in the milk of the transgenic mice. In addition, in a related experiment wherein the GFP reporter gene was co-injected with a second mammary-specific transgene, pINC, no effect on transgene expression was observed. For mice transgenic for the mammary-specific gene alone, expression levels for four different lines were 192, 197, 382, and 415 microg/mL. For mice transgenic for both the mammary-specific transgene and the Oct4-GFP reporter cassette, expression levels for seven different lines were 282, 321, 468, 497, 499, 516, and 806 microg/mL.     

Reed bunting females increase fitness through extra-pair mating with genetically dissimilar males

Females of many socially monogamous species accept or even actively seek copulations outside the social pair bond. As females cannot increase the number of offspring with promiscuous behaviour, the question arises why they engage in extra-pair mating. We used microsatellite data to determine paternity, heterozygosity and genetic relatedness in the reed bunting (Emberiza schoeniclus), a species with high levels of extra-pair paternity (EPP). We found that extra-pair young (EPY) were more heterozygous than within-pair young (WPY). The high heterozygosity of the EPY resulted from a low genetic similarity between females and their extra-pair mates. EPY were heavier and larger when compared with their maternal half-siblings shortly before they left the nest. Recapture data indicated a higher fledgling survival of EPY compared with WPY. Our data suggest that reed bunting females increase the viability of their offspring and thus fitness through extra-pair mating with genetically dissimilar males.     

Relating protein pharmacology by ligand chemistry

The identification of protein function based on biological information is an area of intense research. Here we consider a complementary technique that quantitatively groups and relates proteins based on the chemical similarity of their ligands. We began with 65,000 ligands annotated into sets for hundreds of drug targets. The similarity score between each set was calculated using ligand topology. A statistical model was developed to rank the significance of the resulting similarity scores, which are expressed as a minimum spanning tree to map the sets together. Although these maps are connected solely by chemical similarity, biologically sensible clusters nevertheless emerged. Links among unexpected targets also emerged, among them that methadone, emetine and loperamide (Imodium) may antagonize muscarinic M3, alpha2 adrenergic and neurokinin NK2 receptors, respectively. These predictions were subsequently confirmed experimentally. Relating receptors by ligand chemistry organizes biology to reveal unexpected relationships that may be assayed using the ligands themselves.     

Polyparasitism with Schistosoma mansoni,geohelminths, and intestinal protozoa in rural Côte d'Ivoire

Single species infections with schistosomes, geohelminths, and intestinal protozoans are common over large parts of sub-Saharan Africa, and it is expected that polyparasitism affects a considerable proportion of the population, hence posing a great toll on public health. However, few investigations have been carried out to quantify the extent of polyparasitism. Here, a detailed assessment is reported for the epidemiology of Schistosoma mansoni, geohelminths, and intestinal protozoan infections, with particular emphasis on polyparasitism among 260 community members in rural C?te d'Ivoire. Schistosoma mansoni, Entamoeba coli, and hookworm were the predominant species with prevalences of 71.5, 64.6, and 51.9%, respectively. Only 8 individuals displayed no infection, whereas two-thirds of the population harbored 3 or more parasites concurrently. There were a series of significant pairwise parasite co-occurrences, e.g., between S. mansoni and hookworms and between S. mansoni and E. coli. It is concluded that polyparasitism in the population studied here was very common, which is probably the case also in other areas of rural C?te d'Ivoire and elsewhere in sub-Saharan Africa. These findings call for integrated approaches to effectively control multiple parasitic and protozoan infections.     

STUDIES ON LYSOSOMES : IV. Solubilization of Enzymes during Mitochondrial Swelling and Disruption of Lysosomes by Streptolysin S and Other Hemolytic Agents

Streptolysins S and O from hemolytic streptococci were found to induce mitochondrial swelling and the release of malic dehydrogenase from mitochondria; no other streptococcal products were as active. Mg⁺⁺, cyanide, dinitrophenol, bovine serum albumin, and antimycin all inhibited streptolysin-induced mitochondrial swelling; only the latter two agents prevented release of malic dehydrogenase from the particles. The streptolysins also solubilized beta-glucuronidase from the less numerous lysosomes of mitochondrial fractions. Vitamin A induced swelling of mitochondria with release of malic dehydrogenase and, at higher concentrations, release of beta-glucuronidase. In these effects, streptolysin S and vitamin A resembled cysteine and ascorbate, which induced swelling and lysis of mitochondria together with solubilization of enzymes. In contrast, mitochondrial swelling induced by such agents as phosphate, thyroxine, or substrates was not accompanied by release of enzymes. The release of enzymes from particles is suggested as a criterion for distinguishing "lytic" agents from those which induce mitochondrial swelling dependent upon electron transport. It was possible to dissociate effects on mitochondria and lysosomes in these experiments; less streptolysin was necessary to damage lysosomes than mitochondria; the converse was found with vitamin A. Injury to mitochondria resulted from the direct action of these agents, since the lysosomal enzymes released as a consequence of their action were not capable of inducing mitochondrial swelling or release of enzymes under the conditions studied.