Plasmid-mediated drug resistance of shigellae in Kuwait

Of 153 clinical isolates of shigellae examined, 64.7% belonged toShigella flexneri, 18.9% toSh. sonnei, 11.8% toSh. boydii and 4.6% toSh. dysenteriae. Part of these isolates were resistant to sulfamethoxazole and streptomycin (88.2% each), ampicillin (66.70, tetracycline (63.40 and co-trimoxazole (43.10, with levels of resistance (MIC₅₀ and MIC₉₀) being invariably high. Resistance to three or more drugs (multidrug resistance) was seen in 77.8% of the isolates. All the 25 strains examined for transfer of resistance contained R-plasmids, both autotransferable and non-autotransferable (mobilized by transfer factor X). The frequency of transfer of different r-determinants varied from 2.7 · 10^–8 to 1.4 · 10.     

Versatile shuttle cloning vectors for the unicellular cyanobacterium Anacystis nidulans R2

Abstract 3 new shuttle cloning vectors for gene transfer into Escherichia coli and Anacystis nidulans have been constructed by utilizing the cyanobacterial origin of replication of the small plasmid pANS from A. nidulans . 2 of these new vectors, pXB7 (pDPL13 derivative) and pECAN8 (pUC8 derivative), convey ampicillin resistance, and transform A. nidulans with relatively high frequencies. Vector pXB7 has 10 unique cloning sites; pECAN8 contains 4 cloning sites within the lacZ gene permitting rapid detection of DNA inserts in the presence of Xgal. The third vector, pKBX, has a lower transformation frequency but adds kanamycin resistance as a selectable gene for shuttle vectors of cyanobacteria.     

Structural investigation of the capsular polysaccharide produced by a novel Klebsiella serotype (SK1). Location of O-acetyl substituents using NMR and MS techniques

The capsular polysaccharide of Klebsiella SK1 was investigated by methylation analysis, Smith degradation, and ¹H NMR spectroscopy. The oligosaccharides (P1 and P2) obtained by bacteriophage ΦSK1 degradation of the polymer were studied by methylation analysis, and 1D- and 2D-NMR spectroscopy. The resulting data showed that the patent repeating unit is a branched pentasaccharide having a structure identical to the revised structure recently proposed for Klebsiella serotype K8 capsular polysaccharide.

The 2D-NMR data showed that one third of the glucuronic acid residues in the SK1 polymer are acetylated at O-2, O-3, or O-4. FABMS studies confirmed the presence of monoacetylated glucuronic acid residues. Thus, the relationship between the Klebsiella K8 and SK1 polymers is akin to that found for Klebsiella polysaccharides K30 and K33, which have been typed as serologically distinct yet their structures differ only in the degree of acetylation.     

Biochemical evidence for multiple independent emetine resistance genes in Chinese hamster cells.

Hybridization-complementation studies indicated that mutations in multiple genes can render Chinese hamster cells resistant to the alkaloid translation inhibitor emetine. Two of the genes, emtA and emtB, recognized in Chinese hamster lung and ovary cell lines, respectively, are known to affect the ribosomes of the cells directly. Although mutations in a third gene, emtC, affect the translation apparatus of Chinese hamster peritoneal cells in vitro (Wasmuth et al., Mol. Cell. Biol. 1:58-65, 1981), the molecular product of the emtC locus remains to be determined. To study the molecular basis for genetic complementation among emetine-resistant Chinese hamster cell mutants, we analyzed ribosomal proteins elaborated by complementing, emetine-sensitive hybrid clones (EmtB X EmtA and EmtB X EmtC) and by emetine-resistant clones that segregated from the hybrids. The electrophoretic forms of ribosomal protein S14 (the emtB gene product) elaborated by these clones indicated that the EmtA and EmtC phenotypes are independent of the emtB locus and that the emtA and emtC loci are not chromosomally linked to emtB.     

Unprocessed Bran in Treatment of Diverticular Disease of the Colon

Seventy patients with diverticular disease of the colon were treated with a high-residue, low-sugar diet including unprocessed bran. Follow-up for an average of 22 months showed marked relief of symptoms in 62 patients. Bowel habit was restored towards normal and abdominal discomfort relieved. Only seven patients were unable to give up the use of laxatives. Eight patients did not tolerate the bran diet, and one of these needed surgical treatment. None of the 62 patients who took the diet needed surgery.     

Neonatal androgen and sexual behavior in female house mice

A series of experiments investigated masculine response potential in normal BDF₁ female mice and in females who had been injected with 100 μg of testosterone propionate on the day of birth. Sixty-five percent of BDF₁ females mounted females in estrus; ovariectomy lowered this response potential while injections of TP in adulthood raised masculine RP in both ovariectomized and intact females. Neonatally androgenized females with or without TP in adulthood exhibited the full range of masculine responses including the ejaculatory reflex. Comparisons of elements of sexual behavior are made between neonatally androgenized females and normal males.     

Identification of a new subpopulation of triad junctions isolated from skeletal muscle; Morphological correlations with intact muscle

Summary It has been previously recognized that a number of protocols may cause breakage of the triad junction and separation of the constituent organelles of skeletal muscle. We now describe a fraction of triad junctions which is refractory to the known protocols for disruption. Triads were passed through a French press and the dissociated organelles were separated on a sucrose density gradient, which was assayed for PN200-110, ouabain and ryanodine binding. Ryanodine binding showed a single peak at the density of heavy terminal cisternae. On the other hand, the PN200-110 and ouabain, which are external membrane ligands, bound in two peaks: one at the free transverse tubule region and the other at the light terminal cisternae. Similarly, a two peak pattern of PN200-110 and ouabain binding was observed when triad junctions were broken by the Ca²⁺-dependent protease, calpain, which selectively hydrolyzes the junctional foot protein. The light terminal cisternae vesicles were subjected to three different procedures of junctional breakage: French press, hypertonic salt treatment, and protease digestion using calpain or trypsin. The treated membranes were then centrifuged on density gradients. Only extensive trypsin digestion caused a partial shift of ouabain activity into the free transverse tubule region. These observations suggest that the triads are a composite mixture of breakage susceptible, weak, and breakage resistant, strong, triads. Scatchard analysis of PN200-110 suggests that the transverse tubules of strong triads contain a relatively high number of dihydropyridine receptors compared to those of weak triads. Thin section electron microscopic images of the strong triads comparable to those of intact muscle are presented.