Effects of PGE1 or PGE2 and/or acetazolamide on expulsion of Nippostrongylus brasiliensis from rats

PGE1 and PGE2 have been reported to enhance natural expulsion of Nippostrongylus brasiliensis, a nematode parasite, from the intestine of the rat. Mucus production may also be a key element of worm rejection. Our study attempts to determine if 1) PGE1 or PGE2 alter the normal course of infection with N. brasiliensis in rats, 2) a known mucous enhancing drug, acetazolamide, can augment the rate of worm expulsion, and 3) combinations of prostaglandins and acetazolamide affect N. brasiliensis in the rat. Rats were inoculated with approximately 1,000 infective larvae of N. brasiliensis. Animals were administered, intraduodenally, one of the following: 0.2 ml 0.9% NaCl; 0.2 ml 100% ethanol; 250 micrograms PGE1/0.2 ml 100% ethanol; 250 micrograms PGE2/0.2 ml 100% ethanol; 250 micrograms acetazolamide/0.2 ml 100% ethanol; 250 micrograms PGE1 or PGE2 + 250 micrograms acetazolamide/0.2 ml 100% ethanol. These solutions were given in a single bolus on day 6 postinoculation (PI) or twice daily on days 6-9 PI. Following these treatments the number of parasite ova per gram feces per day for days 6-10 PI and numbers of worms present at necropsy on day 10 PI were determined. Treatment with prostaglandins or acetazolamide or both failed to adversely affect egg deposition by adult female worms or the number of worms in the small intestine. These results do not support the involvement of prostaglandins in the expulsion of N. brasiliensis from the host intestine.     

Effect of ciprofloxacin on subcutaneous abscesses induced with Staphylococcus epidermidis and a foreign body implant in the mouse

Subcutaneous abscesses were induced in mice with Staphylococcus epidermidis strain G19-85 and a foreign body implant. The MIC of ciprofloxacin for this strain was 0.25 microgram/ml. The ciprofloxacin dosage, 120 mg/kg/day, was divided into three injections, administered to the mice subcutaneously at 8 h intervals. Serum concentration kinetics in normal mice (n = 50) were determined. The peak serum level of ciprofloxacin was 3.18 micrograms/ml at the 15 min sampling time; the trough level was 0.53 micrograms/ml at 8 h. Abscesses were found in 96% (n = 49) of the untreated, infected control mice. Three modes of treatment with ciprofloxacin were tested: (1) four prophylactic injections of ciprofloxacin prior to infection reduced abscess formation to 64% (p less than or equal to 0.0002, n = 50). (2) Eleven therapeutic injections, initiated 4 days after infection, reduced abscess formation to 86% (p less than or equal to 0.17, n = 49). (3) One prophylactic injection prior to surgery and five therapeutic injections after infection reduced abscess formation to 43% (p less than or equal to 0.0001, n = 49). Culture results correlated with the abscess formation rates.     

Observations on Membranes of Mycoplasma laidlawii Strain B

The cytoplasmic membrane of Mycoplasma laidlawii strain B is solubilized by anionic and nonionic detergents, succinylation, phospholipase A, alkaline phosphatase, trypsin, and chymotrypsin. Cationic detergents are without effect, as are chelating agents, even in the presence of high concentrations of monovalent cation. The detergent-solubilized membrane exhibits one peak in the analytical ultracentrifuge, but the sedimentation coefficient is dependent upon concentration of detergent. Simple dialysis does not remove all of the sodium dodecylsulfate except from lipid-depleted membrane particles. Membranes bind sodium dodecylsulfate but acetone powders of membranes do not. Sulfated alcohols with chain lengths of C(14) and C(16) are more tightly bound than dodecylsulfate. A constant amount of di- and trivalent cation is bound by the membrane upon aggregation. Only a portion of this cation is removable with chelating agents. No chelating agent is bound by these aggregates. A portion of the lipid-depleted membrane particles is solubilized by negatively charged lipids and detergents, giving rise to aggregates in the presence of divalent cation. Fractionations of detergent-solubilized membranes by preparative gel electrophoresis and ammonium sulfate were inconclusive. Density gradient centrifugation of succinylated membranes yielded at least five fractions which exhibited homogeneity by ultracentrifugation. Analytical gel electrophoresis of these fractions demonstrated heterogeneity. The composition of these five fractions suggested separation of protein from lipid.     

Growth yields of bacteria on selected organic compounds

Cell yields were determined for two bacterial soil isolants grown aerobically in minimal media on a variety of synthetic organic compounds. 1-Dodecanol, benzoic acid, phenylacetic acid, phenylglyoxylic acid, and diethylene, triethylene, and tetraethylene glycols were tested. Two “biochemicals,” succinate and acetate, were also tested for comparison. Yields were calculated on the basis of grams of cells obtained per mole of substrate utilized, gram atom of carbon utilized, mole of oxygen consumed, and equivalent of “available electrons” in the substrates. This latter value appears to be nearly constant at 3 g of cells per equivalent of “available electrons.” Yields predicted on this basis for other bacteria and for yeasts on other substrates are in fair agreement with reported values.     

Muramic Acid Assay in Sediments

An improved chromatographic assay for muramic acid which is sufficiently sensitive for marine sandy sediments is described; it involves acid hydrolysis, thin-layer chromatography, and gas-liquid chromatography.     

Rhabdospora thelohani Laguessé, 1895 (Apicomplexa): new host and geographic records with taxonomic considerations.

New fish species and geographic records for Rhabdospora thelohani Laguessé, 1895 (rodlet cells) are presented. Additionally, the ultrastructure of R. thelohani in Alburnoides bipunctatus ohridanus Karaman, Borostomias antarcticus (L?nnberg), Leuciscus cephalus albus Bonaparte and Rutilus rubilio (Bonaparte) is compared with that reported by other authors and with members of Subphylum Apicomplexa. The ultrastructure of R. thelohani was similar in all the fish species examined; however, the organism was not present in all members of any single species and had intertissue density variations. Rhabdospora thelohani is pyriform, averaging in size 7 X 12 micrometer, with a basal nucleus. The surface complex is composed of a layer (0.5 micrometer diameter) formed by microfilaments (9.3 nm) and an outer trilaminar membrane (9.3 nm). The cytoplasm contains structures identical to rhoptries, micronemes and subpellicular microtubules. Mitochondria, Golgi apparatus, and rough endoplasmic reticulum were not observed, althouth free ribosomes were present and arranged in a vesicular pattern. The observations suggest that the organism moves between cell of epithelial layers and is either released into a lumen intact or passively or actively discharges its contents into a lumen. Results from this study indicate that R. thelohani should be considered a member of Apicomplexa unless definitive evidence is presented to the contrary.     

Characterization of Bacteroides gingivalis by direct fluorescent antibody staining and cellular fatty acid profiles

Bacteroides gingivalis is a newly proposed species which includes strains isolated from the mouth. Thirteen strains of B. gingivalis isolated from three geographic locations in the United States and France were examined with direct fluorescent antibody staining and analysis of total cellular fatty acids and compared with 16 strains of B. asaccharolyticus of nonoral origin by the same methods. Bacteroides gingivalis strains reacted with the B. gingivalis conjugate (fluorescein isothiocyanate labeled antibody reagent) only, while the B, asaccharolyticus strains reacted with the B. asaccharolyticus conjugate only. The B. gingivalis strains showed negative fluorescence with fluorescein isothiocyanate conjugates for other black-pigmented Bacteroides species. The specificity of the B. gingivalis conjugate was demonstrated by its failure to stain 88 strains of aerobic and anaerobic bacteria other than B. gingivalis. The fatty acid profiles of B. gingivalis and B. asaccharolyticus were readily distinguishable. The B. gingivalis profile was also distinguishable from those of other pigmenting Bacteroides species on the basis of concentration ratios among the characteristic components. These results support the species separation of B. gingivalis and B. asaccharolyticus. Further, they indicate the usefulness of cellular fatty acid profiles as an adjunct to the use of specific fluorescent antibody conjugates for identification of Bacteroides species.