Relationship between bacterial counts and endotoxin concentrations in the air of wastewater treatment plants.

The relationship between bacterial counts and endotoxin concentrations in air samples was studied. Selective EMB medium favored the growth of a larger portion of airborne gram-negative bacteria than LES Endo or MacConkey medium and was a good predictor of the endotoxin levels determined with a chromogenic Limulus assay of the air of wastewater treatment plants. The bacterial counts determined with nonselective media correlated poorly with airborne endotoxin levels; however, R2A medium yielded higher viable bacterial counts than TYG medium. Direct counting by epifluorescence microscopy yielded the highest bacterial counts, but no correlation was obtained between total bacterial counts and endotoxin concentrations.     

Preparation of 14C-labeled algal samples for liquid scintillation counting

Four commonly used techniques for preparation of ¹⁴C-labeled algal samples on membranes for liquid scintillation counting were compared and a simple technique for apparent net assimilation measurement from aqueous samples was introduced. All four techniques yielded similar radioactivities from the test cultures and are thus suitable for measurements of ¹⁴C algal samples. The possibly carcinogenic solvent dioxane was not necessary with PCS scintillation cocktail for dissolving radioactivity from algae on filters.     

A colcemid-sensitive mechanism involved in regulation of chromosome movements during meiotic pairing

Active movements of the chromosomes may be needed in the process, where homologous chromosomes find each other during the meiotic pairing. Because the components of the cytoskeleton are generally believed to be responsible for all movements in living nonmuscle cells, we have analyzed the regulation of the movements of zygotene chromosomes in the male rat by using specific inhibitors of the assembly of the various components of the cytoskeleton. — Colcemid, an inhibitor of microtubule formation, completely inhibited the chromosome movements in vitro at a concentration of 1 g/ml. This was associated with a damage of the nuclear envelope revealed by the electron microscopic analysis. Another inhibitor of microtubule formation, vinblastine, was ineffective below the level of general toxicity (100 g/ml). A specific microfilament inhibitor, cytochalasin B was similarly ineffective. — The findings suggest the presence of a specific colcemid-sensitive mechanism in the nuclear envelope of the zygotene spermatocytes, which regulates the movements of the chromosomes during meiotic pairing.     

Analysis of permethylated hexopyranosyl-2-acetamido-2-deoxyhexitols by g.l.c.-m.s.

The major product obtained on acetonation of d-mannose with a 2-molar excess of isopropenyl methyl (or ethyl) ether is 4,6-O-isopropylidene-α-d-mannopyranose (3a), the product of kinetic acetonation: a larger excess of the reagent leads, to the 2,3:4,6-diisopropylidene acetal (6). The course of the reaction and side-products formed were examined in detail. The 1,2,3-triacetate of 3a was deacetonated to give α-d-mannopyranose 1,2,3-triacetate; similar reactions were performed on the β anomers. The 1-acetate of the diacetal 6 could be selectively deacetonated to give 1-O-acetyl-2,3-O-isopropylidene-α-d-mannopyranose. The reactions provide access to protected derivatives of d-mannose, and partially acylated derivatives, having modes of substitution different from those obtainable by classical acetonation procedures conducted under conditions of thermodynamic control.     

An increased frequency of chromosomal changes and SCE's in cultured blood lymphocytes of 12 subjects vaccinated against smallpox

Summary An increased frequency of chromosomal changes and sister chromatid exchanges was detected in 10 women 7 days after smallpox vaccination.     

Mineralization of carbon and nitrogen in acid forest soil treated with fast and slow-release nutrients

The effects of slow (apatite, biotite) and fast-release nutrients (P, K, Mg) on C and N mineralization in acid forest soil were studied. These nutrients were applied alone or together with urea or urea and limestone. The production of CO₂ in the soil samples taken one and three growing seasons after the application was lower in the soils treated with the fast-release nutrients than in the untreated soils. Similar reduction of microbial activity was not seen after the apatite and apatite+biotite treatments. In the first growing season, urea and urea+limestone enhanced CO₂ production, but after three growing seasons, the opposite was true. Apatite and apatite+biotite added together with urea did not compensate for the decreasing effect of urea on the CO₂ production. The addition of fast-release salts increased somewhat the concentration of NH _inf4 ^sup+ in the soil and more NH₄ ⁺ accumulated during laboratory incubation in the soil samples taken one growing season after the application. The urea addition immediately increased the concentrations of NH₄ ⁺ and of NO₃ ⁻ in the soil, but, three growing seasons after application, urea had only a slight increasing effect on mineral N content of the soil. Slow-release nutrients seem to have a more favourable effect than fast-release salts on nutrient turnover in acid forest soil.     

Expression and localization of androgen receptor-interacting protein-4 in the testis

Androgen receptor-interacting protein 4 (ARIP4) belongs to the SNF2 family of proteins involved in chromatin remodeling, DNA excision repair, and homologous recombination. It is a DNA-dependent ATPase, binds to DNA and mononucleosomes, and interacts with androgen receptor (AR) and modulates AR-dependent transactivation. We have examined in this study the expression and cellular localization of ARIP4 during postnatal development of mouse testis. ARIP4 was detected by immunohistochemistry in Sertoli cell nuclei at all ages studied, starting on day 5, and exhibited the highest expression level in adult mice. At the onset of spermatogenesis, ARIP4 expression became evident in spermatogonia, pachytene, and diplotene spermatocytes. Immunoreactive ARIP4 antigen was present in Leydig cell nuclei. In Sertoli cells ARIP4 was expressed in a stage-dependent manner, with high expression levels at stages II-VI and VII-VIII. ARIP4 expression patterns did not differ significantly in testes of wild-type, follicle-stimulating hormone receptor knockout, and luteinizing hormone receptor knockout mice. In testes of hypogonadal mice, ARIP4 was found mainly in interstitial cells and exhibited lower expression in Sertoli and germ cells. In vitro stimulation of rat seminiferous tubule segments with testosterone, FSH, or forskolin did not significantly change stage-specific levels of ARIP4 mRNA. Heterozygous ARIP4(+/-) mice were haploinsufficient and had reduced levels of Sertoli-cell specific androgen-regulated Rhox5 (also called Pem) mRNA. Collectively, ARIP4 is an AR coregulator in Sertoli cells in vivo, but the expression in the germ cells implies that it has also AR-independent functions in spermatogenesis.