Donor and recipient genotype and heterosis effects on survival and prenatal growth of transferred mouse embryos

Reciprocal embryo transfers amongst two inbred strains (C3HeB/FeJ and SWR/J) and their F1 cross (C3SWF1) were used to examine donor and recipient genotype and heterosis effects on survival and prenatal growth of mouse embryos. Among inbred strains, significant recipient genotype effects were detected for both embryo survival (P less than 0.01) and prenatal growth (P less than 0.05), while no donor genotype effects were observed. The recipient effect on overall embryo survival was due to a higher proportion of C3H recipients maintaining pregnancy to term than SWR recipients (P less than 0.01), rather than survival within litters. Irrespective of their own genotype, embryos developing in C3H uteri achieved larger body weights (P less than 0.01) and longer tail lengths (P less than 0.05) at birth than did embryos developing in SWR uteri. Recipient heterosis was not significant, while donor heterosis was significant for prenatal growth traits (P less than 0.001).     

SV40-transformed human lung fibroblasts secrete a 92-kDa type IV collagenase which is identical to that secreted by normal human macrophages

We have reported that SV40-transformed human lung fibroblasts secrete a 92-kDa metalloprotease which is not detectable in the parental cell line IMR-90. We now present the complete structure of this enzyme along with the evidence that it is identical to the 92-kDa metalloprotease secreted by normal human alveolar macrophages, phorbol ester-differentiated monocytic leukemia U937 cells, fibrosarcoma HT1080 cells, and cultured human keratinocytes. A similar, perhaps identical, enzyme can be released by polymorphonuclear cells. The preproenzyme is synthesized as a polypeptide of predicted Mr 78,426 containing a 19 amino-acid-long signal peptide and secreted as a single 92,000 glycosylated proenzyme. The purified proenzyme complexes noncovalently with the tissue inhibitor of metalloproteases (TIMP) and can be activated by organomercurials. Activation with phenylmercuric chloride results in removal of 73 amino acids from the NH2 terminus of the proenzyme, yielding an active form capable of digesting native types IV and V collagen. The in vitro substrate specificity of the enzyme using these substrates was indistinguishable from that of the 72-kDa type IV collagenase. The 92-kDa type IV collagenase consists of five domains; the amino-terminal and zinc-binding domains shared by all members of the secreted metalloprotease gene family, the collagen-binding fibronectin-like domain also present in the 72-kDa type IV collagenase, a carboxyl-terminal hemopexin-like domain shared by all known enzymes of this family with the exception of PUMP-1, and a unique 54-amino-acid-long proline-rich domain homologous to the alpha 2 chain of type V collagen.     

Effect of culture media onLactobacillus hydrophobicity and electrophoretic mobility

The hydrophobicity of six strains representing three species ofLactobacillus was measured using dextran-polyethylene glycol contact angle measurements. These ranged from 123.6° forLactobacillus casei douche to 26.2° forL. casei RC-17 under identical growth conditions. The results indicated that the nutritional environment affected bacterial hydrophobicity. Electrophoretic mobilities of the lactobacilli were also determined and found to be negative for all specimens, and to vary with growth media, especially when sugars were added to urine. The electrophoretic mobility histograms showed one main peak for all strains, exceptLactobacillus acidophilus T-13 which had two peaks, suggesting two morphological sizes or types within its population. In addition, strain T-13 was more positively charged than the other five strains after growth in agar, urine, and supplemented urine. The use of contact angle and electrophoretic mobility techniques allows examination of cell surface properties of lactobacilli that may have importance in the colonization of mucosal epithelia.     

Liquid Chromatographic Procedure for Fermentation Product Analysis in the Identification of Anaerobic Bacteria

High-performance liquid chromatography with a cation-exchange resin-packed column was used to determine fermentation products of several known and unknown Clostridium species. The column was operated at 30°C, and isocratic elution was done with 0.013 N H₂SO₄. Sample preparation for high-performance liquid chromatographic analysis required only membrane filtration. Glucose and formate were readily determined. Quantitative results were easily obtained. Chromatograms of eight unknown strains could be matched with chromatograms of at least one of the type culture strain chromatograms. In some cases, additional testing was necessary before identification could be made. The same conclusions were reached by parallel testing with gas chromatography to determine fermentation products. High-performance liquid chromatography is simple to apply and, under some conditions, is faster than gas chromatography for fermentation product analysis.     

A high risk twin study of combat-related PTSD comorbidity.

Combat-related posttraumatic stress disorder (PTSD) is highly comorbid with other mental disorders. However, the nature of the relationship between PTSD and other mental disorders remains unclear. A discordant high-risk twin design was used on data from a sub-sample of the male-male twin pair members of the Vietnam Era Twin Registry to examine whether patterns of comorbidity are consistent with a psychopathological response to combat exposure or reflect familial vulnerability to psychopathology. Mental disorders were assessed via the Mental Health Diagnostic Interview Schedule Version III - Revised. Discordant monozygotic within-pair comparisons revealed that PTSD probands had higher symptom counts and diagnostic prevalences of mood and anxiety disorders than their non-combat exposed co-twins. Monozygotic co-twins of PTSD probands had significantly more mood disorder symptoms than monozygotic co-twins of combat controls or dizygotic co-twins of veterans with PTSD. These findings suggest that a) major depression, generalized anxiety disorder and panic disorder are part of a post-combat response syndrome; b) a shared familial vulnerability also contributes to the association between PTSD and major depression, PTSD and dysthymia, and c) this shared vulnerability is mediated by genetic factors.     

Phylogenetic relationships of chemoautotrophic bacterial symbionts of Solemya velum say (Mollusca: Bivalvia) determined by 16S rRNA gene sequence analysis.

The protobranch bivalve Solemya velum Say (Mollusca: Bivalvia) houses chemoautotrophic symbionts intracellularly within its gills. These symbionts were characterized through sequencing of polymerase chain reaction-amplified 16S rRNA coding regions and hybridization of an Escherichia coli gene probe to S. velum genomic DNA restriction fragments. The symbionts appeared to have only one copy of the 16S rRNA gene. The lack of variability in the 16S sequence and hybridization patterns within and between individual S. velum organisms suggested that one species of symbiont is dominant within and specific for this host species. Phylogenetic analysis of the 16S sequences of the symbionts indicates that they lie within the chemoautotrophic cluster of the gamma subdivision of the eubacterial group Proteobacteria.     

An Experimental Evaluation of Genetic Correlation

Heritability and genetic correlations realized from both single-trait and antagonistic index selection were compared with paternal half-sib estimates. Primary attention was focused on the genetic correlation between six-week body weight and six-week tail length. Parameters realized from single-trait selection were in excellent agreement with paternal half-sib estimates. However, the realized genetic correlation between six-week body weight and six-week tail length obtained from index selection was significantly greater than the other estimates. Differential inbreeding levels and realized selection intensities were considered and rejected as being causative factors for these results. Linkage disequilibrium probably was not a factor either, as the base population had been randomly mated and randomly selected with a large effective population size for many generations. It was concluded that with antagonistic index selection, the pleiotropic effects of genes may be more powerful in retarding response in aggregate genotype than current theory would suggest. Replication of all selected and control lines allowed the use of between-line estimators of sampling variances of realized genetic parameters in the above comparisons. Generally, standard errors of realized genetic parameters were much smaller than corresponding paternal half-sib standard errors. Thus, selection was an efficient method of estimation.     

Partial purification of the glucocorticoid receptor from rat liver: a rapid, two-step procedure using DNA-cellulose.

Glucocorticoid receptor from rat liver was purified 1800-fold by a rapid two-step procedure using DNA-cellulose. The procedure is based on increasing the affinity of the glucocorticoid-receptor complex for DNA by heating the complex. During a first chromatography step, unheated glucocorticoid-receptor complex is separated from cytosol proteins that bind to DNA-cellulose with high affinity. During a second chromatographic step, heat-treated glucocorticoid-receptor complex is separated from proteins with low affinity for DNA. The partially purified complex is functionally competent in that it is taken up by isolated rat liver nuclei.