Factors affecting male-production in Hydatina

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Factors affecting male-production in Hydatina

     

Ethylene Oxide Gaseous Sterilization: II. Influence of Method of Humidification

The duration of the equilibration period between admission of water vapor and subsequent introduction of gaseous ethylene oxide to an evacuated sterilizer chamber was studied with respect to its effect on the inactivation of spores of Bacillus subtilis var. niger under simulated practical conditions. Introduction of a water-adsorbing cotton barrier between the spores and an incoming gas mixture of water vapor and ethylene oxide caused a marked increase in the observed thermochemical death time of the spore populations. This effect was negated by admission of water vapor one or more minutes prior to introduction of ethylene oxide gas. Increases in temperature and relative humidity of the system promoted passage of water vapor through the cotton barriers and diminished their effect.     

Phylogenetic diversification of immunoglobulin genes and the antibody repertoire

Immunoglobulins are encoded by a large multigene system that undergoes somatic rearrangement and additional genetic change during the development of immunoglobulin-producing cells. Inducible antibody and antibody-like responses are found in all vertebrates. However, immunoglobulin possessing disulfide-bonded heavy and light chains and domain-type organization has been described only in representatives of the jawed vertebrates. High degrees of nucleotide and predicted amino acid sequence identity are evident when the segmental elements that constitute the immunoglobulin gene loci in phylogenetically divergent vertebrates are compared. However, the organization of gene loci and the manner in which the independent elements recombine (and diversify) vary markedly among different taxa. One striking pattern of gene organization is the "cluster type" that appears to be restricted to the chondrichthyes (cartilaginous fishes) and limits segmental rearrangement to closely linked elements. This type of gene organization is associated with both heavy- and light-chain gene loci. In some cases, the clusters are "joined" or "partially joined" in the germ line, in effect predetermining or partially predetermining, respectively, the encoded specificities (the assumption being that these are expressed) of the individual loci. By relating the sequences of transcribed gene products to their respective germ-line genes, it is evident that, in some cases, joined-type genes are expressed. This raises a question about the existence and/or nature of allelic exclusion in these species. The extensive variation in gene organization found throughout the vertebrate species may relate directly to the role of intersegmental (V<==>D<==>J) distances in the commitment of the individual antibody-producing cell to a particular genetic specificity. Thus, the evolution of this locus, perhaps more so than that of others, may reflect the interrelationships between genetic organization and function.      

Inhibition of muscle force by vanadate.

Vanadate (Vi), an analogue of inorganic phosphate (Pi), is known to bind tightly with a long half life to the myosin MgATPase site, producing a complex which inhibits force. Both of these ligands bind to an actin.myosin.ADP state that follows the release of Pi in the enzymatic cycle, and their effects on muscle fibers and proteins in solution provide information on the properties of this state. The inhibition of active force generation began to occur at a [Vi] of 5 microM and was 90% complete at a [Vi] of 1 mM. Hill plots of the inhibition of force by Vi approximated that expected for a simple binding isotherm. Similar plots were obtained at both 25 degrees C and 5 degrees C. A simple binding isotherm is not expected to occur in a muscle fiber where steric constraints imposed by the intact filaments should introduce more complexity into the energetics of ligand binding. The inhibition of MgATPase activity for acto-subfragment-1 to 50% of controls occurred at a [Vi] which was only 20-fold higher than that required to inhibit force generation in fibers to the same level. Some models of actomyosin interactions would predict that the range of [Vi] required for complete force inhibition in fibers and the difference in the [Vi] required for inhibition in fibers and of myosin in solution would both be much larger.     

Cloning and characterization of cDNA encoding canine alpha-L-iduronidase. mRNA deficiency in mucopolysaccharidosis I dog.

alpha-L-Iduronidase is a lysosomal enzyme, the deficiency of which causes mucopolysaccharidosis I (MPS I); a canine MPS I colony has been bred to test therapeutic intervention. The enzyme was purified to apparent homogeneity from canine testis and found to consist of two electrophoretically separable proteins that had common internal peptides but differed at their amino termini. A 57-base oligonucleotide, corresponding to the most probable codons of the longest peptide, was used to screen a canine testis cDNA library. Three cDNAs were isolated, two of which lacked the 5'-end whereas the third was full-length except for a small internal deletion. The composite sequence encodes an open reading frame of 655 amino acids that includes all sequenced peptides. The amino terminus of the larger protein, glutamic acid 26, is at the predicted signal peptide cleavage site, whereas the amino terminus of the smaller protein is leucine 106. There are six potential N-glycosylation sites and a non-canonical polyadenylation signal, CTTAAA. A search of GenBank showed that the amino acid sequence of alpha-L-iduronidase has similarity to that of a bacterial beta-xylosidase. A full-length cDNA corresponding to the composite sequence was constructed (pcIdu) and inserted into the pSVL expression vector (pSVcIdu). Two days after Cos-1 cells were transfected with pSVcIdu, their intracellular and secreted level of alpha-L-iduronidase activity has increased 8- and 22-fold, respectively, over the endogenous activity. Fibroblasts of MPS I dogs, which have no alpha-L-iduronidase activity, lacked the normal alpha-L-iduronidase mRNA of 2.2 kilobases and contained instead a trace amount of a 2.8-kilobase species. Isolation and characterization of an expressible alpha-L-iduronidase cDNA represents the first step toward mutation analysis and replacement therapy.     

Purification and immunocytochemical localization of kafirins inSorghum bicolor (L. Moench) endosperm

Summary Kafirins are the storage proteins of sorghum and are found in protein bodies in the seed endosperm. They have been classified as -, -, and -kafirins according to differences in molecular weight, solubility, and structure. The kafirins were purified, amino acid composition was determined, and immunolocalization methods were used to determine the organization of the protein bodies and distribution of kafirins throughout the endosperm. All three groups of kafirins were low in lysine. -Kafirins and -kafirins were relatively high in cysteine, and -kafirins were relatively high in methionine. Transmission electron microscopy showed that protein bodies in the peripheral endosperm were spheroid with concentric rings and few darkly stained inclusions. In contrast, protein bodies of the central endosperm were irregularly shaped with a higher proportion of darkly stained material. The light staining regions of the protein bodies are composed primarily of -kafirins with minor portions of - and -kafirins. The dark staining regions, however, are composed primarily of - and -kafirins. Immunoelectron microscopy showed that protein bodies in the peripheral endosperm contain predominantly a-kafirin with minor amounts of - and -kafirin. Central endosperm protein bodies are also predominantly -kafirin, but have a higher proportion of -kafirin and -kafirin than the peripheral endosperm protein bodies.Abbreviations GAR-HRP Goat anti-rabbit horseradish peroxidase - IgG immunoglobulin G - 2-ME 2-mercaptoethanol - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - TBS Tris buffer saline - TBS-T Tris buffer saline with Tween - TBS-T-B Tris buffer saline with Tween and bovine serum albumin - TCA trichloroacetic acid - UV ultraviolet