A linkage map of the canine genome

A genetic linkage map of the canine genome has been developed by typing 150 microsatellite markers using 17 three-generation pedigrees, composed of 163 F2 individuals. One hundred and thirty-nine markers were linked to at least one other marker with a lod score > or = 3.0, identifying 30 linkage groups. The largest chromosome had 9 markers spanning 106.1 cM. The average distance between markers was 14.03 cM, and the map covers an estimated 2073 cM. Eleven markers were informative on the mapping panel, but were unlinked to any other marker. These likely represent single markers located on small, distinct canine chromosomes. This map will be the initial resource for mapping canine traits of interest and serve as a foundation for development of a comprehensive canine genetic map.     

Inhibition of phosphoinositide metabolism or chelation of intracellular calcium blocks FSH-induced but not spontaneous meiotic resumption in mouse oocytes

Mammalian oocytes are arrested at the diplotene phase of the first meiotic division until ovulation. In the mouse, germinal vesicle breakdown (GVBD) and progression to metaphase II is thought to be triggered by a positive signal originating in the follicular cells following stimulation by the luteinizing hormone (LH) surge. Isolated, fully grown oocytes can also undergo spontaneous reinitiation of meiosis in vitro in the absence of gonadotrophin stimulation. To investigate the mechanism of meiotic resumption, inhibitors of phosphoinositide metabolism and an intracellular calcium chelator were used during maturation in vitro under different conditions. In a series of experiments, isolated cumulus cell-oocyte complexes (COCs) maintained in meiotic arrest by hypoxanthine were induced to resume meiosis by treatment with follicle-stimulating hormone (FSH). Under these conditions, both LiCl and neomycin, which inhibit phosphoinositide hydrolysis, produced a dose-dependent inhibitory effect on meiotic resumption. Similar results were obtained when FSH-induced meiotic resumption was observed in the presence of the acetoxymethyl ester form of 1, 2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA/AM), an intracellular calcium chelator. In hypoxanthine-arrested oocytes, GVBD induced by epidermal growth factor (EGF), which mimics FSH action in in vitro maturation, was also repressed by LiCl and neomycin. Conversely, meiotic resumption triggered by a pulse of 8-bromo-cyclic adenosine monophosphate (8-Br cAMP) was not affected by these two inhibitors. In experiments in which oocytes were cultured under conditions which permit spontaneous meiotic maturation, resumption of meiosis was not affected by either inhibition of phosphoinositide hydrolysis or chelation of intracellular calcium. Therefore, it appears that meiotic resumption induced by hormone stimulation requires activation of the phosphoinositide pathway and mobilization of intracellular calcium. In contrast, spontaneous maturation probably occurs through a different mechanism because it is not affected by inhibition of this signaling pathway.     

The effect of sperm-mucus interaction test on the outcome of in vitro fertilization and ovulation induction combined with intrauterin insemination

The relationships between paroxysmal nocturnal hemoglobinuria (PNH), aplastic anemia (AA), and myelodysplastic syndrome (MDS) are not clear. Here we describe a patient, J20, who developed a reciprocal translocation of chromosome 12 and PNH during follow-up of AA. All metaphases in CD59-deficient bone marrow mononuclear cells had the translocation, whereas none of the CD59-deficient cells had it, indicating that the PNH clone coincided with a cell population bearing the chromosomal aberration. We found a somatic single-base deletion mutation in the PIG-A gene of this patient's peripheral blood cells. This is the first patient with PNH with a PNH clone containing a chromosomal translocation.     

In vivo assessment of hepatic-arterial and portal-venous components of liver perfusion: concise communication

An in vivo technique for assessment of the relative contributions of hepatic artery and portal vein to liver perfusion has been developed in the rat. Dynamic scintigrams have been obtained following i.v. bolus injection of Tc-99m sulfur colloid. Temporal separation of the arterial and venous phases has been verified by hepatic-arterial ligation and portacaval diversion. The former procedure abolishes the early arterial phase of normal uptake. Portacaval diversion similarly eliminates the delayed venous phase. Assessment of the individual components of liver perfusion is of promise in the investigation of hepatic dysfunction.     

PIXE analysis of Trojan gold jewelry

Technological advancements in the production of gold jewelry from the Troad in northwest Anatolia in the third millennium BC are investigated by PIXE. Results indicate a higher percentage of Cu at the interface between joined pieces of gold than exists elsewhere on the jewelry, away from joinings. The results indicate the probable use of copper salts as a flux in the manufacture of jewelry with granulation.     

Evaluation of malolactic-deficient strains of Lactobacillus plantarum for use in cucumber fermentations

In the fermentation of cucumbers, naturally occurring strains of Lactobacillus plantarum decarboxylate malic acid (MDC⁺) to form lactic acid and CO₂. Since CO₂ buildup in the brine contributes to bloater damage of the cucumbers, it is desirable to have strains of L. plantarum that do not decarboxylate malic acid (MDC^-1). Two MDC^- mutants, obtained by N-methyl-N′-nitro-N-nitrosoguanidine mutagenesis of different MDC⁺ strains, and their parent strains of L. plantarum wre evaluated in laboratory fermentations of filter-sterilized cucumber juice and of whole cucumbers as to growth rate, end-products, residual malic acid, and competitiveness with the natural flora. Effects of temperature (15 to 40°C) and NaCl concentration (0-6%) on growth in cucumber juice were determined. One MDC^-1 strain, designated MOP3-M6, was selected for further development because of its relative dominance in cucumber ferementations, high residual malic acid concentration after fermentation and greater salt tolerance as compared to its closest rival mutant culture. Growth lag and generation times averaged 1·6 and 1·2 times greater, respectively, for the MOP3-M6 mutant than its parent. However, this mutant may still have application as a starter culture for cucumber fermentation, particularly under relatively aseptic conditions.