Legionella pneumophila in Cooling Towers: Fluctuations in Counts, Determination of Genetic Variability by Pulsed-Field Gel Electrophoresis (PFGE), and Persistence of PFGE Patterns

The concentrations of Legionella pneumophila in cooling towers may vary considerably over short periods of time, producing significant fluctuations throughout the year. Despite genetic variability, in small geographical areas the same indistinguishable pulsed-field gel electrophoresis patterns may be shared among different cooling towers and persist over time.     

traT gene sequences, serum resistance and pathogenicity-related factors in clinical isolates of Escherichia coli and other gram-negative bacteria

The R6-5 plasmid-specified outer membrane protein, TraT protein, has previously been shown to mediate resistance to bacterial killing by serum. Colony hybridization with a 700 bp DNA fragment carrying most of the traT gene was used to examine the prevalence of traT in Gram-negative bacteria, particularly strains of Escherichia coli, isolated from clinical specimens. traT was found in isolates of E. coli, Salmonella, Shigella and Klebsiella, but not in Pseudomonas, Aeromonas or Plesiomonas, nor in the few isolates of Enterobacter, Proteus, Acinetobacter, Citrobacter, Serratia or Yersinia that were examined. It was detected in a significantly higher proportion of the E. coli strains isolated from the blood of patients with bacteraemia/septicaemia or from faeces of patients with enteric infections (50-70%) than in that of strains isolated from normal faeces (20-40%). The incidence of traT in strains isolated from cases of urinary tract infections was variable. traT was found to be frequently associated with production of the K1 capsule and with the carriage of ColV plasmids, but not with the carriage of R plasmids, nor with serum resistance or the production of haemolysin.     

Residual beta-cell function in type II diabetes and evaluation of the hepatic insulin extraction

Insulin and C-peptide (free insulin and C-peptide in insulin-treated patients) were measured after glucose stimulation in nine Type II diabetics on chlorpropamide, eleven insulin-treated maturity-onset diabetics and in 8 normal controls. Dissociation between C-peptide and insulin response to glucose was observed in several diabetics. The relation between incremental molar areas under C-peptide and insulin curves, after glucose challenge (delta CPR - delta IRI/delta CPR) were used to evaluate the hepatic insulin extraction in all but the insulin-treated diabetics. The lower insulin requirements and better control of the short-duration insulin-treated maturity-onset diabetics in relation to the long-term ones could not be explained either by the residual insulin secretion or by the level of "insulin antibodies". The chlorpropamide-responsive patients presented higher insulin levels after the glucose challenge and a lower hepatic insulin extraction than the non-responsive ones.     

Mutants blocked in penicillin biosynthesis show a deletion of the entire penicillin gene cluster at a specific site within a conserved hexanucleotide sequence

The organization of the genes of the penicillin cluster has been studied in three different mutants of P. chrysogenum impaired in penicillin biosynthesis. The three blocked mutants (derived from the parental strain P. chrysogenum Bb-1) lacked the genes pcbAB, pcbC and penDE of the penicillin biosynthetic pathway and were unable to form isopenicillin N synthase and isopenicillin N acyltransferase. All strains were identified as P. chrysogenum derivatives by fingerprinting analysis with (GTG)_n as a probe. The borders of the deleted region were cloned and sequenced, showing the same junction point in the three mutants. The deleted DNA region was found to be identical to that described in P. chrysogenum npe10. The frequent deletion of the pen gene cluster at this point may indicate that this cluster is located in an unstable genetic region, flanked by hot spots of recombination, that is easily lost by mutagen-induced recombination.     

Experimental paracoccidioidomycosis of hamster inoculated in the cheek pouch

We compared the granuloma morphology and immune response of hamsters inoculated withParacoccidioides brasiliensis (Pb) into the cheek pouch, which lacks lymphatic drainage, and into the footpad, which is rich in lymphatics. Our objective was to better understand the modulation ofPb granuloma in an immunocompetent animal inoculated in an immunologically privileged site. The humoral immune response (ELISA) and cell mediated immunity (footpad test) became positive on days 7 and 14, respectively in animals inoculated into footpad and on days 35 and 60 in animals inoculated into the pouch. Typical epithelioid granulomas were observed at both sites on day 14. The number of fungi gradually decreased from the beginning of the experiment in footpad lesions, but only after day 35 in pouch granulomas, when cell mediated immunity was detectable. The results indicate that typical epithelioid paracoccidioidomycotic granulomas may develop in the absence of a detectable immune response; however, they are incapable of controlling fungal reproduction. Lack of lymphatic drainage delays the appearance of a detectable immune response, but with time fungi escape from the pouch, elicit an immune response and reach other organs. Our results further indicate the importance of the lymphatics in the pathogenesis of paracoccidioidomycosis.Abbreviations HCP hamster cheek pouch - Pb Paracoccidioides brasiliensis - Pbmycosis Paracoccidioidomycosis     

Dialysable leukocyte extracts modify the course of experimental paracoccidioidomycosis in the Syrian hamster

The effect of dialysable leukocyte extracts (DLE) obtained from hamsters immunized withParacoccidioides brasiliensis (immune DLE) and from non-immunized hamsters (non-immune DLE) was studied in hamsters inoculated withP. brasiliensis by the intratesticular route. Treatment with immune or non-immune DLE was started during the third week of infection and was repeated at 7, 11, 15 and 19 weeks. A group of untreated infected animals was used as control. Animals were submitted to the delayed hypersensitivity skin test toP. brasiliensis antigen (PbAg) in vivo and assayed in vitro by the macrophage migration inhibition test in the presence of Phytohemagglutinin (PHA) and PbAg and by immunodiffusion for specific antibody. The animals were sacrificed at 4, 8, 12, 16 and 20 weeks. The morphology and extension of the lesions were studied at the inoculation site, and in lymph nodes, lungs, liver, spleen and kidneys. In contrast to the controls, animals treated with both DLEs maintained a positive cell-mediated immune response throughout the experiment and developed less extensive infection with a significantly lower number of fungi in the lesions. The results suggest that immune and non-immune DLE preparations modified the evolution of experimental paracoccidioidomycosis with equal efficiency. This similarity may be explained by the immunoregulatory activities of both extracts.     

Phytochemical Characterization of Cannabis sativa L. Roots from Northeastern Brazil

This article describes the phytochemical study of Cannabis sativa roots from northeastern Brazil. The dried plant material was pulverized and subjected to exhaustive maceration with ethanol at room temperature, obtaining the crude ethanolic extract (Cs-EEBR). The volatile compounds were analyzed by gas chromatography coupled with mass spectrometry (GC/MS), which allowed to identify 22 compounds by comparing the linear retention index (LRI), the similarity index (SI) and the fragmentation pattern of the constituents with the literature. By this technique the major compounds identified were: friedelan-3-one and β-sitosterol. In addition, two fractions were obtained from Cs-EEBR by classical column chromatography and preparative thin layer chromatography. These fractions were analyzed by NMR and IR and together with the mass spectrometry data allowed to identify the compounds: epifriedelanol, friedelan-3-one, β-sitosterol and stigmasterol. The study contributed to the phytochemical knowledge of Cannabis sativa, specifically the roots, as there are few reports on the chemical constituents of this part of the plant.