The Detection of Hamster Connexins: A Comparison of Expression Profiles with Wild-Type Mouse and the Cancer-Prone Min Mouse

The open reading frames of 17 connexins from Syrian hamster (using tissues) and 16 connexins from the Chinese hamster cell line V79, were fully (Cx30, Cx31, Cx37, Cx43 and Cx45) or partially sequenced. We have also detected, and partially sequenced, seven rat connexins that previously were unavailable. The expression of connexin genes was examined in some hamster organs and cultured hamster cells, and compared with wild-type mouse and the cancer-prone Min mouse. Although the expression patterns were similar for most organs and connexins in hamster and mouse, there were also some prominent differences (Cx29 and 30.3 in testis; Cx31.1 and 32 in eye; Cx46 in brain, kidney and testis; Cx47 in kidney). This suggests that some connexins have species-specific expression profiles. In contrast, there were minimal differences in expression profiles between wild type and Min mice. Species-specific expression profiles should be considered in attempts to make animal models of human connexin-associated diseases.     

1-Alkyl-3-amino-5-aryl-1H-[1,2,4]triazoles: novel synthesis via cyclization of N-acyl-S-methylisothioureas with alkylhydrazines and their potent corticotropin-releasing factor-1 (CRF(1)) receptor antagonist activities.

Cyclizations of alkylhydrazines with N-acyl-S-methylisothioureas, readily synthesized from acyl chlorides, sodium thioisocyanate, dialkylamines then methyl iodide in a one-pot reaction, gave 1-alkyl-3-dialkylamino-5-phenyltriazoles 7 as major products. The regioisomers were assigned through the use of NOE NMR experiments. While bearing a N-bis(cyclopropyl)methyl-N-propylamino group, this series of compounds shows very good binding affinity on the human CRF₁ receptor. Among them, 1-methyl-3-[N-bis(cyclopropyl)methyl-N-propylamino]-5-(2,4-dichlorophenyl)-1H-[1,2,4]triazole 7a had the best binding affinity for the CRF₁ receptor (K_i=9 nM).     

Expression of heterologous genes for wall teichoic acid in Bacillus subtilis 168

Summary A localized region of low DNA sequence homology was revealed in two strains of Bacillus subtilis by a specific 100-fold reduction in transformation by W23 DNA of the tag1 locus, a teichoic acid marker of strain 168. Fifty nine rare recombinants, hybrid at this locus, had all acquired donor-specific phage resistance characters, while losing those specific to the 168 recipient. Chemical analysis of isolated cell walls showed that these modifications are associated with major changes in the wall teichoic acids. Genetic analysis demonstrated that determinants for the ribitol phosphate polymer of strain W23 had been transferred to 168, replacing those for the glycerol phosphate polymer in the recipient. All W23 genes coding for poly(ribitol phosphate) in the hybrids and those specifying anionic wall polymers in strain 168 are clustered near hisA. In addition to tag1, the region exchanged extends just beyond gtaA in some hybrids, whereas in others it may include the more distant gtaB marker, encompassing a region sufficient to contain at least 20 average-sized genes. Surface growth, flagellation, transformability and sporulation all appeared normal in hybrids examined. Recombinants without a major wall teichoic acid from either strain were not found, suggesting that an integral transfer of genes for poly(ribitol phosphate) from W23 had occurred in all hybrids isolated. We interpret these results as indicating an essential role for anionic wall polymers in the growth of B. subtillis.     

Genomic distribution of copia-like transposable elements in somatic tissues and during development of Drosophila melanogaster

The genomic distribution of elements of the copia, 412, B 104, mdg 1, mdg 4 and 1731 transposon families was compared by the Southern technique in DNA preparations extracted from brains, salivary glands and adult flies of two related Drosophila lines. The copia, 412 and mdg 1 sequences were also probed in DNA from sperm, embryos, and 1st and 2nd instar larvae. The homogeneity of the patterns observed shows that somatic transposition is unlikely to occur frequently. A correlation between mobility and the euchromatic or heterochromatic location of transposable elements is discussed. In addition, an explanation of the variable band intensities of transposable elements in Southern autoradiographs is proposed.     

Position Effect Variegation in Drosophila Melanogaster: Relationship between Suppression Effect and the Amount of Y Chromosome

Position effect variegation results from chromosome rearrangements which translocate euchromatic genes close to the heterochromatin. The euchromatin-heterochromatin association is responsible for the inactivation of these genes in some cell clones. In Drosophila melanogaster the Y chromosome, which is entirely heterochromatic, is known to suppress variegation of euchromatic genes. In the present work we have investigated the genetic nature of the variegation suppressing property of the D. melanogaster Y chromosome. We have determined the extent to which different cytologically characterized Y chromosome deficiencies and Y fragments suppress three V-type position effects: the Y-suppressed lethality, the white mottled and the brown dominant variegated phenotypes. We find that: (1) chromosomes which are cytologically different and yet retain similar amounts of heterochromatin are equally effective suppressors, and (2) suppression effect is positively related to the size of the Y chromosome deficiencies and fragments that we tested. It increases with increasing amounts of Y heterochromatin up to 60-80% of the entire Y, after which the effect reaches a plateau. These findings suggest suppression is a function of the amount of Y heterochromatin present in the genome and is not attributable to any discrete Y region.     

Transmission of a New Mycoplasma-Like Organism (MLO) from Cuscuta odorata (Ruiz et Pav.) to Herbaceous Plants and Attempts to its Elimination in the Vector

A new MLO-type, originating from a holoparasite plant Cuscuta odorata (Ruiz et Pav.) causing stunting and reduction of flower- and leaf size on Catharanthus roseus (L.) G. Don. (HEINTZ 1986) was transmitted to Apium graveolens L., Plantago major L., Bellis perennis L. and Cirsium japonicum hybrid. The observed symptoms on the test plants probably caused by the MLO have not yet been described in the literature. The symptomatology on these herbaceous plants gives further data in order to classify the MLO as a new one which is named Guscuta latent MLO (Cl-MLO). Attempts to transmit the pathogens by the leafboppers Euscelidius variegates (Kirschbaum) and Euscelis lineolatus (Brullé) failed. It also was impossible to elimmate the MLO completely from Cuscuta odorata by heat treatment and antibiotic application. However, we succeeded in eliminating the pathogens from Catharanthus roseus by heat treatment.     

Expression of endogenous receptors for neoglycoproteins, especially lectins, that allow fiber typing on formaldehyde-fixed, paraffin-embedded muscle biopsy specimens. A glycohistochemical, immunohistochemical, and glycobiochemical study

A panel of biotinylated (neo)glycoproteins was used for specific detection of endogenous sugar receptors, especially lectins, in formaldehyde-fixed, paraffin-embedded muscle biopsy specimens from human deltoid, quadriceps, and biceps muscles, tibial and quadriceps muscles of rat, and bovine masseter muscle. The glycohistochemical probes used consisted of conjugates of a labeled, histochemically inert carrier protein and various covalently linked, histochemically crucial sugar moieties. Specific binding of alpha-L-fucoside, beta-D-galactoside, beta-D-xyloside, and alpha-D-mannoside to muscle sections was detected, showing no species-specific differences. The presence of receptors for the N-acetylated sugars in natural glycoconjugates, and for sugars with a phosphate group, i.e., mannose-6-phosphate and galactose-6-phosphate, was demonstrated glycohistochemically. However, these binding specificities revealed species-specific differences, e.g., the absence of N-acetyl-D-galactosamine-specific receptors or galactose-6-phosphate-specific receptors in rat muscle. Other charged sugars included glucuronic acid and sialic acid, which bound only to ox and rat muscle or failed to reveal their respective receptors in all types of muscle investigated. This different extent of staining with anionic probes served as a further control to ascertain carbohydrate binding specificity. Positive glycohistochemical reaction developed within sarcomeres only at the level of A-bands. Granular staining was observed in the sarcoplasm among the myofibrils and also in the subsarcolemmal regions. Differences in expression of glycohistochemically detectable sugar receptors were noted between type 1, type 2A, and type 2B fibers. The molecular properties of one type of glycohistochemically detectable sugar receptor were inferred both immunohistochemically and biochemically. An antiserum against an endogenous beta-galactoside-specific lectin from muscle tissue localized this lectin within sections consistently similar to (neo)glycoproteins, detecting beta-galactoside-specific receptor(s). This similarity of binding patterns strongly supports the assumption that (neo)glycoproteins with beta-galactoside termini indeed bind to the respective endogenous lectin. The lectin-specific antiserum enabled us to ascertain that glycohistochemical fiber typing corresponds to enzyme histochemical typing. Moreover, biochemical purification using affinity chromatography and subsequent affinity elution revealed only the immunohistochemically detectable beta-galactoside-specific lectin. Consequently, use of a panel of neoglycoproteins, when frozen sections for histochemical analysis are not available, co