Isolation and Antifungal Susceptibility of <Emphasis Type="Italic">Exophiala dermatitidis</Emphasis> Isolates from Human Stool Samples in Nigeria

We screened a total of 460 stool samples from humans with and without underlying disease for the black yeast and neurotrope, Exophiala dermatitidis using conventional and molecular identification procedures. Sixteen (3.5%) samples were positive. Twelve out of the sixteen positive samples where the fungus was recovered were from individuals who had diarrhoea at the moment of isolation. Two asymptomatic positive cases were within the age bracket of 21–30. Susceptibility testing of the strains using the CLSI M38 protocol suggests that almost all the strains were susceptible to amphotericin B, 5 fluorocytosine, itraconazole, fluconazole and voriconazole. Considering the health risk currently posed by this organism in Asia, especially among healthy younger subjects of the population and the scarcity of data on this fungus in Africa in general and Nigeria in particular, some recommendations were suggested.     

Statistical analysis of in situ hybridization data: derivation and use of the zmax test.

There are many situations in which grain distributions resulting from in situ hybridization of radioactively labeled probes to unique genes should be subjected to a statistical analysis. However, the problems posed by analysis of in situ hybridization data are not straightforward, and no completely satisfying method is currently available. We have developed a procedure in which the major and any number of minor site(s) of hybridization may be specifically located and the significance of each tested. This zmax procedure first tests the overall distribution for departure from randomness and then identifies significantly overlabeled whole chromosomes (or chromosome arms or other large segments), a process that may be repeated to pinpoint significantly overlabeled regions within these chromosomes. We describe in detail the derivation of the zmax statistic, present tables of significant zmax levels, and show with examples how zmax is used in tests of significance of in situ hybridization data.     

Effect of continuous application of manures and fertilizers on rhizosphere microflora in arecanut palm

Summary The rhizosphere microflora of arecanut palm under continuous application of organic manures and inorganic fertilizers was studied. The nutrients applied are 100 g N, 40 g P₂O₅ and 140 g K₂O/palm/year in the form of organics and inorganics. The application of organic manure increased the microbial population. The increase in microbial population was observed between the rhizosphere samples collected at 0–30cm and 30–60 cm depths. The surface cultivation of soil increased the microbial population.Trichoderma sp. andAspergillus sp. dominated in therhizosphere of arecanut palm. Contribution No. 208. Central Plantation Crops Research Institute, Vittal-574243, Karnataka, India.     

Soil and plant tests for available sulfur in wetland rice soils

Summary Soil tests, plant performance, and plant tissue analyses were used to study the availability of sulfur to wetland rice in 30 Philippine soils. The critical concentrations of available sulfur by the calcium phosphate, lithium chloride, ammonium acetate, and hydrochloric acid extractions were 9, 25, 30, and 5 mg/kg, respectively. The critical total sulfur limits were 0.11% in the shoot at maximum tillering 0.055% in the straw at maturity, and 0.065% in the grain. The critical N:S ratio was 15 in the shoot at maximum tillering, 14 in the straw at maturity, and 26 in the grain. The critical sulfate-sulfur limit was 150 mg/kg in the shoot at maximum tillering and 100 mg/kg in the straw at maturity. The critical sulfate-sulfur/total sulfur percentage ratio was 15% in the shoot at maximum tillering and the straw at maturity. Plant performance, judged by appearance and yield of dry matter, straw, and grain, was generally poorer in the sulfur deficient soils than in the other soils. Although the calcium phosphate and ammonium acetate methods gave a better correlation between plant performance and available sulfur than the others, all four methods separated sulfur-deficient soils from non-deficient ones. The hydrochloric acid method merits further study because it is simple and versatile.     

Human globin gene expression after gene transfer

Human globin genes can be transferred into mouse and human erythroid cells in culture, and can be appropriately expressed at the mRNA level in these cells. A plasmid containing a human beta globin gene is expressed in mouse erythroleukemia cells (MELC), and another containing a human epsilon or gamma gene is expressed in human erythroleukemia (K562) cells. A neomycin resistance (neoR) gene on the plasmids has been used to select for those cells containing the transferred globin genes; this selection may favor the expression of the globin genes by providing chromosomal positions requiring neoR expression. Analyzing clones resistant to G418, a neomycin analogue, demonstrated globin mRNA expression and induction. Retroviral vectors have also been used to transfer and appropriately express human beta genes in MELC. In addition, a plasmid containing a dihydrofolate reductase (DHFR) gene as well as neoR and beta globin genes has been used to amplify and express beta globin mRNA in MELC. These experiments suggest that high level appropriate expression of human beta globin genes is feasible and provides potentially useful approaches to the long-range goal of gene therapy for sickle cell anemia and beta thalassemia.     

Osteogenic precursor cells in repair osteogenesis

Histological and electron-microscopic radioautographic investigations of regenerating medullar tissue were performed in rabbits following curettage. Low differentiated connective tissue cells were shown to possess the highest proliferative activity. DNA synthesis mainly took place in low differentiated, endothelial and osteogenic cells. It is suggested that low differentiated cells take part in histogenesis of regenerating medullar tissue, including osteo- and angiogenesis.     

Fatty acid composition of Escherichia coli cells and their viability in air

Experiments on E. coli used as a model have revealed that fatty-acid composition is one of the characteristics which determine the viability of bacteria in the air. The viability of microbial cells in the air has been shown to increase with the increase of the pool of cyclopropane acids and the palmitic acid/palmitoleic acid ratio in the cells, irrespective of their genotype and the phase of their growth.     

Mechanism of action of N-acetylglucosaminyl-N-acetylmuramylalanyl-D-isoglutamine on the nonspecific anti-infection resistance of mice

The stimulating influence of glucose-containing muramyldipeptide (GMDP) on the nonspecific resistance of mice was shown to depend on the features of the pathogenesis of the infection. Thus, the intraperitoneal injection of GMDP increased the survival rate of mice infected with Escherichia coli, but had no stimulating effect on the resistance of the animals to Salmonella typhimurium natural infection in whose pathogenesis macrophages played an essential role. Experiments demonstrated that GMDP was capable of enhancing the ingestive function of macrophages, but did not increase their bactericidal activity with respect to this infection.