Extensive dermatophytoses caused by Trichophyton mentagrophytes and Microsporum canis in a patient with AIDS

Retrospective studies have shown the occurrence of episodes of deep or superficial fungal infections in 58 to 81% of HIV/AIDS patients as a result of impairment of cell immunity. We describe a case of disseminated cutaneous dermatophytoses caused by Trichophyton mentagrophytes and Microsporum canis in a patients with AIDS. Diagnostic and therapeutic problems in relation to this unsual presentation are emphasized as well as the importance of an early mycologic diagnosis to prescribe antifungal therapy.     

Distribution of intraventricularly injected horseradish peroxidase in cerebrospinal fluid compartments of the rat spinal cord

Summary The circulation of the cerebrospinal fluid along the central canal and its access to the parenchyma of the spinal cord of the rat have been analyzed by injection of horseradish peroxidase (HRP) into the lateral ventricle. Peroxidase was found throughout the central canal 13 min after injection, suggesting a rapid circulation of cerebrospinal fluid along the central canal of the rat spinal cord. It was cleared from the central canal within 2 h, in contrast with the situation in the brain tissue, where it remained in the periventricular areas for 4 h. In the central canal, HRP bound to Reissner's fiber and the luminal surface of the ependymal cells; it penetrated through the intercellular space of the ependymal lining, reached the subependymal neuropil, the basement membrane of local capillaries, and appeared in the lumen of endothelial pinocytotic vesicles. Furthermore, it accumulated in the labyrinths of the basement membrane contacting the basolateral aspect of the ependymal cells. In ependymocytes, HRP was found in single pinocytotic vesicles. The blood vessels supplying the spinal cord were classified into two types. Type-A vessels penetrated the spinal cord laterally and dorsally and displayed the tracer along their external wall as far as the gray matter. Type-B vessels intruded into the spinal cord from the medial ventral sulcus and occupied the anterior commissure of the gray matter, approaching the central canal. They represented the only vessels marked by HRP along their course through the gray matter. HRP spread from the wall of type-B vessels, labeling the labyrinths, the intercellular space of the ependymal lining, and the lumen of the central canal. This suggests a communication between the central canal and the outer cerebrospinal fluid space, at the level of the medial ventral sulcus, via the intercellular spaces, the perivascular basement membrane and its labyrinthine extensions.     

Degradation of 4-nitrobenzoate via 4-hydroxylaminobenzoate and 3,4-dihydroxybenzoate in Comamonas acidovorans NBA-10

Comamonas acidovorans NBA-10 was previously shown to degrade 4-nitrobenzoate via 4-hydroxylaminobenzoate and 3,4-dihydroxybenzoate. Washed cells, grown on a mixture of 4-nitrobenzoate and ethanol, stoichiometrically produced ammonium and 3,4-dihydroxybenzoate from 4-nitrobenzoate under anaerobic conditions provided ethanol was present. In cell extracts 4-hydroxylaminobenzoate was degraded to ammonium and 3,4-dihydroxybenzoate, but this activity was lost upon dialysis. No requirement for a cofactor was found, but rather reduced incubation conditions were necessary to restore enzyme activity. The 4-hydroxylamino-degrading enzyme was purified and the role of this novel type of enzyme in the degradation of nitroaromatic compounds is discussed.Abbreviation 4-ABA 4-aminobenzoate - 4-NBA 4-nitrobenzoate - 4-HABA 4-hydroxylaminobenzoate - 3,4-diHBA 3,4-dihydroxybenzoate     

Singlet oxygen induced mutation spectrum in mammalian cells.

In order to characterize the molecular nature of singlet oxygen (1O2) induced mutations in mammalian cells, a SV40-based shuttle vector (pi SVPC13) was treated with singlet oxygen arising from the thermal decomposition of the water-soluble endoperoxide of 3,3'-(1,4-naphthylidene) dipropionate (NDPO2). After the passage of damaged plasmid through monkey COS7 cells, the vector was shuffled into E. coli cells, allowing the screening of supF mutants. The mutation spectrum analysis shows that single and multiple base substitutions arose in 82.5% of the mutants, the others being rearrangements. The distribution of mutations within the supF gene is not random and some hotspots are evident. Most of the point mutations (98.4%) involve G:C base pairs and G:C to T:A transversion was the most frequent mutation (50.8%), followed by G:C to C:G transversion (32.8%). These results indicate that mutagenesis in mammalian cells, mediated by 1O2-induced DNA damage, is targeted selectively at guanine residues.     

NCI-H716 cells as a model for endocrine differentiation in colorectal cancer

In colonic neoplasms, endocrine differentiation is encountered not only in carcinoid tumors but also in adenocarcinomas, where endocrine cells may represent a distinct line of differentiation in the tumor. The significance of endocrine differentiation in colorectal cancer is not well established, partly because of the paucity of tumor cell lines which can serve as a model for studying endocrine differentiation. In this report we describe the properties of NCI-H716 cells, a cell line derived from a poorly differentiated adenocarcinoma of the caecum, under various in vitro conditions and as xenografts in athymic mice. Phenotypical properties were immunohistochemically assessed using a panel of differentiation related antibodies, and also by Northern blot analysis and by electron microscopy. Receptors for biogenic amines and peptide hormones were analyzed by ligand binding assay. These studies show that:

Different chromosomal localization of two adenylyl cyclase genes expressed in human brain

Summary Recently, we characterized a cDNA clone that encodes a human brain adenylyl cyclase (HBAC1). In the present study, we identified a second population of mRNA suspected to encode a new brain adenylyl cyclase (HBAC2). The amino acid sequence of HBAC2 displays significant homology with HBAC1 in the highly conserved adenylyl cyclase domain (250 aminio acids), found in the 3 cytoplasmic domain of all mammalian adenylyl cyclases. However, outside this domain, the homology is extremely low, suggesting that the corresponding mRNA originates from a different gene. We report here the first chromosomal localization of the adenylyl cyclase genes determined by in situ hybridization of human metaphase chromosomal spreads using human brain cDNA probes specific for each mRNA. The probe corresponding to HBAC1 exhibited a strong specific signal on chromosome 8q24, with a major peak in the band q24.2. In contrast, the HBAC2 probe hybridized to chromosome 5p15, with a major peak in the band p15.3. The two cDNAs hybridized at the two loci without any cross reactivity. Thus, in human brain, a heterogeneous population of adenylyl cyclase mRNAs is expressed, and the corresponding genes might be under the control of independent regulatory mechanisms.Abbreviations C catalytic part of adenylyl cyclase - BBAC bovine brain - HBAC human brain - ROAC rat olfactory - RLAC rat liver - RTAC rat testis adenylyl cyclase - G guanine nucleotide GTP binding protein (s, stimulatory; i, inhibitory)     

Peptidergic regulation of the Limulus midgut

1. The morphology and innervation of the midgut (intestine) in the horseshoe crab, Limulus polyphemus was investigated. The organization of this tissue was examined with routine histology. Radioimmunoassay, immunohistochemistry and high performance liquid chromatography were employed to detect, localize and identify peptidergic innervation of the midgut. The actions of synthetic and native proctolin-like and FMRFamide-like peptides were compared on the isolated midgut preparation. 2. Levels of proctolin and FMRFamide were determined in extracts of Limulus midgut tissue using radioimmunoassay. High levels of proctolin-like immunoreactivity (69.5 +/- 11.3 ng/g) were detected, while levels of FMRFamide-like immunoreactivity (0.8 +/- 0.2 ng/g) were less. Proctolin levels were equally distributed, while the levels of FMRFamide-like immunoreactivity exhibited an anterior bias. 3. Proctolin- and FMRFamide-like immunoreactivities in the Limulus midgut were localized with immunohistochemistry. Proctolin- and FMRFamide-immunoreactive elements were detected in intestinal nerve branches and individual fibers running along the surface of the midgut in whole-mount preparations. In sectioned tissue, staining for these peptides was observed throughout the midgut, typically associated with muscle bands and fibers. Only a few immunoreactive cell bodies were observed. 4. Proctolin, and several FMRFamide-like peptides produced distinct and opposing actions on the isolated Limulus midgut preparation. Proctolin elicited contracture and rhythmic contractions of this tissue, while FMRFamide and N-terminally extended analogs of FLRFamide relaxed gut tension. FMRFamide-like peptides partially reversed the excitatory actions of proctolin. 5. Proctolin- and FMRFamide-like peptides in Limulus midgut extracts were partially characterized with high performance liquid chromatography. One peak of proctolin-like activity was detected on a linear gradient of 18 to 31.5% acetonitrile. The native proctolin-like peptide produced excitatory actions on the isolated midgut preparation which were indistinguishable from those produced by synthetic proctolin. Several peaks of FMRFamide-like bioactivity (Busycon radula protractor muscle assay) were detected with a linear gradient of 5 to 30% acetonitrile. Fractions from two distinct peaks produced FMRFamide-like inhibitory effects on the isolated Limulus midgut preparation. These findings suggest a role for proctolin-like and FMRFamide-like peptides as regulators of intestinal motility in Limulus.     

Struvite precipitation by soil and fresh water bacteria

Struvite precipitation by 161 bacterial strains isolated from soil and fresh water was analyzed. The results showed that the ability to form struvite is not widespread among these bacteria. Struvite precipitation was influenced by environmental factors and could be enhanced by changing the experimental conditions. There was no clear relationship between the taxonomic status of a given strain and its ability to precipitate struvite. However, bacteria of the genusPseudomonas showed a greater tendency to precipitate struvite than organisms of the remaining genera studied, and five new genera were identified as struvite producers.     

Isolation and characterization of a recombination defective-dependent bacteriophage ofRhodobacter sphaeroides

A new virulent bacteriophage, designated RZ1, was isolated from a local pond on the facultative phototrophic bacteriumRhodobacter sphaeroides ZZ101. Electron microscopic studies revealed that, in general morphology, phage RZ1 resembles the bacteriophage ofEscherichia coli. The host range of phage RZ1 is limited to some strains ofR. sphaeroides. The phage genome consists of double-stranded DNA of about 44 kb lacking cohesive ends and seems to present terminal redundancy and cyclic permutation. RZ1 phage may carry out a lytic cycle only in recombination-defective mutants ofR. sphaeroides. Nevertheless, a derivative of the RZ1 phage, termed RW1, able to grow in recombination-proficient strains ofR. sphaeroides, has also been obtained. In vitro restriction analysis of both RZ1 and RW1 phages shows the presence of a rearrangement in their DNA. Generalized transduction of Str^r and Rif^r chromosomal markers has not been detected with either RZ1 or RW1 phages.