Cercarial shedding from <Emphasis Type="Italic">Galba</Emphasis><Emphasis Type="Italic">truncatula</Emphasis> infected with <Emphasis Type="Italic">Fasciola</Emphasis><Emphasis Type="Italic">gigantica</Emphasis> of distinct geographic origins

Galba truncatula snails were experimentally infected with either of two different isolates of Fasciola gigantica, originating from Egypt or China, to determine the influence of these isolates on the characteristics of snail infections. The survival rates of G. truncatula on day 30 post-exposure were 90.0% and 60.2% in the Egyptian and Chinese groups, respectively. The frequency of cercaria-shedding snails within the Egyptian group was 79.8%, whereas in the Chinese group it was 22.4%. The parasite origin had a significant effect on the durations of the prepatent and patent periods. The mean number of cercariae shed from the Egyptian group was significantly greater than that shed from the Chinese group (a mean of 275.5 per cercaria-shedding snail compared with 29.0). These results could be explained by the fact that G. truncatula might be a natural intermediate host for F. gigantica in Egypt, and the greater adaptability of the Egyptian miracidia of F. gigantica to unusual snail hosts. These results demonstrate the influence of the geographic origin of the parasite on the success of trematodes infecting snails.     

Cysteine proteinases from promastigotes of <Emphasis Type="Italic">Leishmania</Emphasis> (<Emphasis Type="Italic">Viannia</Emphasis>) <Emphasis Type="Italic">braziliensis</Emphasis>

Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that has a wide geographical distribution and is a severe public health problem. The cysteine proteinase B (CPB) from Leishmania spp. represents an important virulence factor. In this study, we characterized and localized cysteine proteinases in L. (V.) braziliensis promastigotes. By a combination of triton X-114 extraction, concanavalin A-affinity, and ion exchange chromatographies, we obtained an enriched fraction of hydrophobic proteins rich in mannose residues. This fraction contained two proteinases of 63 and 43 kDa, which were recognized by a CPB antiserum, and were partially sensitive to E-64 in enzymatic assays with the peptide Glu-Phe-Leu. In confocal microscopy, the CPB homologues localized in the peripheral region of the parasite. This data together with direct agglutination and flow cytometry assays suggest a surface localization of the CPB homologues. The incubation of intact promastigotes with phospholipase C reduced the number of CPB-positive cells, while anti-cross-reacting determinant and anti-CPB antisera recognized two polypeptides (63 and 43 kDa) derived from phospholipase C treatment, suggesting that some CPB isoforms may be glycosylphosphatidylinositol-anchored. Collectively, our results suggest the presence of CPB homologues in L. braziliensis surface and highlight the need for further studies on L. braziliensis cysteine proteinases, which require enrichment methods for enzymatic detection.     

Use of <Emphasis Type="Italic">MET3</Emphasis> promoters for regulated gene expression in <Emphasis Type="Italic">Ashbya gossypii</Emphasis>

A central tool for gene function analysis is the construction mutant strains. This can be done conveniently in A. gossypii using PCR-based tools. The deletion of essential genes can be performed since initial transformants are sheltered in a heterokaryotic mycelium, which contains nuclei with both wild type and mutant alleles. The analysis of mutant phenotypes in A. gossypii is regularly started by germinating spores, which contain only one nucleus. Thus, selection can be used to identify mutant germ cells and germlings. However, such an analysis yields only mutant mycelia if the deleted gene is not essential. We describe the use of the regulatable Saccharomyces cerevisiae and A. gossypii MET3 promoters as novel tools to regulate gene expression in A. gossypii. Conditional expression was tested using GFP and lacZ-reporter genes. Regulation of MET3 promoters was found to be dependent on methionine but not on cysteine and down-regulation to about 1/10 of the initial expression levels was achieved. We used the A. gossypii WAL1 and CYK1 genes as models to demonstrate that MET3 promoters could regulate the expression of these genes and reveal their mutant phenotypes depending on the presence or absence of methionine. Finally, we show that the AgMET3 promoter contains two Cpf1-binding sites and that AgCPF1 can complement the S. cerevisiae cpf1 methionine auxotrophy.     

<Emphasis Type="Italic">KLRB</Emphasis>1 gene expression is suppressed in human cancer tissues

The KLRB1 gene encodes the CD161 receptor in natural killer cells (NK cells). The gene is also expressed in the NKT cells. Both types of cells are cytotoxic and capable of recognizing and eliminating various tumor, virus-infected, and allotransplant cells. The biological function of human CD161 is not clear. It is suggested that it can be involved in the regulation of both cytotoxic cell functions and cytokine production. As the majority of cancer patients show down-regulation of the immune system, we hypothesized that the level of KLRB1 expression might also be suppressed in cancer cells. Here, we show that KLRB1 gene expression was suppressed in tumor tissues in 68% of patients with non-small-cell lung cancer (p < 0.0001) and in 57% of patients with esophageal squamous-cell carcinoma (p = 0.0003). The high frequency of KLRB1 gene suppression in cancer patients suggests that this gene can represent a highly informative marker of lung and esophageal cancers.     

<Emphasis Type="Italic">KNQ1</Emphasis>, a<Emphasis Type="Italic"> Kluyveromyces lactis</Emphasis> gene encoding a drug efflux permease

Several transport systems play an important role in conferring multiple drug resistance, presumably due to their catalysis of the energy-dependent extrusion of a large number of structurally and functionally unrelated compounds out of the cells. In the present work, the gene named KNQ1 (encoding Kluyveromyces lactis membrane permease) was cloned by functional complementation of the cycloheximide-hypersensitivity phenotype of the Saccharomyces cerevisiae mutant strain lacking a functional PDR5 gene. The isolated gene exhibited 48.9% identity with the S. cerevisiae ATR1 gene conferring resistance to aminotriazole and 4-nitroquinoline-N-oxide and encoded a protein of 553 amino acids. When present in multicopy, it efficiently complemented the phenotype associated with the pdr5 or pdr1pdr3 mutations in S. cerevisiae. Overexpression of the KNQ1 gene in K. lactis wild-type strains led to resistance against several cytotoxic compounds, like 4-nitroquinoline-N-oxide, 3-aminotriazole, bifonazole and ketoconazole. The gene was assigned to K. lactis chromosome III and its expression was found to be responsive to oxidative stress induced by hydrogen peroxide. Based on the phenotype of homologous and heterologous transformants, we propose that the gene encodes a membrane-associated component of the machinery responsible for decreasing the concentration of several toxic compounds in the cytoplasm of yeast cells.Communicated by K. Breunig     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> and <Emphasis Type="Italic">cagA</Emphasis> and <Emphasis Type="Italic">vacA</Emphasis> gene status in children from Brazil with chronic gastritis

Helicobacter pylori has been shown to be strongly associated with chronic gastritis, gastric and duodenal ulceration, and is a risk factor for gastric carcinoma. Histology, urease, culture, and polymerase chain reaction have been employed as for H. pylori diagnostic methods, pre and post treatment or during follow-up of dyspeptic adult individuals referred for endoscopy. In order to obtain a more-sensitive and specific method for H. pylori detection, we evaluated gastric body and antrum biopsies of 134 consecutive Brazilian consecutive dyspeptic children aged 1-16 years by rapid urease test, histology and polymerase chain reaction using two pairs of oligonucleotides. Our results indicated that polymerase chain reaction with Southern blotting and hybridization with specific chemiluminescent probes increased the number of positive H. pylori patients by 35%. The genotyping of H. pylori strains directly from gastric biopsy using the same nucleic acid methodology revealed that there is no association of chronic gastritis in our infant patients with vacA s1 and the presence of the cagA gene. These data suggest an initial infection of children with normal mucosa and probably others factors than vacA s1 genotype or the presence of the cagA gene are associated with the onset of gastric disease. Altogether, our results reinforce the need for using more sensitive diagnostic methods in order to understand the role of H. pylori in the genesis of gastric disease in children and its progression in adults.     

Functional analysis of <Emphasis Type="Italic">Kluyveromyces lactis</Emphasis> carboxylic acids permeases: heterologous expression of <Emphasis Type="Italic">KlJEN1</Emphasis> and <Emphasis Type="Italic">KlJEN2</Emphasis> genes

The present work describes a detailed physiological and molecular characterization of the mechanisms of transport of carboxylic acids in Kluyveromyces lactis. This yeast species presents two homologue genes to JEN1 of Saccharomyces cerevisiae: KlJEN1 encodes a monocarboxylate permease and KlJEN2 encodes a dicarboxylic acid permease. In the strain K. lactis GG1888, expression of these genes does not require an inducer and activity for both transport systems was observed in glucose-grown cells. To confirm their key role for carboxylic acids transport in K. lactis, null mutants were analyzed. Heterologous expression in S. cerevisiae has been performed and chimeric fusions with GFP showed their proper localization in the plasma membrane. S. cerevisiae jen1Δ cells transformed with KlJEN1 recovered the capacity to use lactic acid, as well as to transport labeled lactic acid by a mediated mechanism. When KlJEN2 was heterologously expressed, S. cerevisiae transformants gained the ability to transport labeled succinic and malic acids by a mediated mechanism, exhibiting, however, a poor growth in malic acid containing media. The results confirmed the role of KlJen1p and KlJen2p as mono and dicarboxylic acids permeases, respectively, not subjected to glucose repression, being fully functional in S. cerevisiae. O. Queirós and L. Pereira contributed equally to this work.     

<Emphasis Type="Italic">In vivo</Emphasis> activity of <Emphasis Type="Italic">Sapindus saponaria</Emphasis> against azole-susceptible and -resistant human vaginal <Emphasis Type="Italic">Candida</Emphasis> species

Background  

Study of in vivo antifungal activity of the hydroalcoholic extract (HE) and n-BuOH extract (BUTE) of Sapindus saponaria against azole-susceptible and -resistant human vaginal Candida spp.     

Identification of 108 SNPs in <Emphasis Type="Italic">TSC</Emphasis>, <Emphasis Type="Italic">WNK1</Emphasis>, and <Emphasis Type="Italic">WNK4</Emphasis> and their association with hypertension in a Japanese general population

The deletion of thiazide-sensitive Na–Cl cotransporter (TSC, SLC12A3) causes Gitelmans syndrome characterized by low blood pressure, while deletions of the WNK1 (PRKWNK1) and WNK4 (PRKWNK4) genes cause familial hypertension known as pseudohypoaldosteronism type II. Recent studies have revealed that cell surface expression of TSC is regulated by WNK1 and WNK4. We hypothesized that molecular variations in TSC, WNK1, and WNK4 could lead to an increased morbidity of hypertension. We identified 52, 35, and 21 polymorphisms in Japanese hypertensives by sequencing the entire coding regions of TSC, WNK1 and WNK4, respectively. Twenty-one representative polymorphisms were genotyped in 1,818 Japanese individuals (771 subjects with hypertension and 1,047 controls) randomly sampled in Suita city. The results indicated that the systolic blood pressure in men with the CT+TT genotype in WNK4 C14717T was 3.1 mmHg higher than those with the CC genotype (p=0.042) after adjustment with confounding factors such as age, BMI, hyperlipidemia, diabetes mellitus, antihypertensive drug use, smoking, and drinking. Multivariate logistic regression analysis (with adjustment for the same parameters) in men revealed that the odds ratio for the presence of hypertension of the CT+TT genotype in C14717T to the CC genotype was 1.62 (p=0.010, 95% confidence interval, 1.12–2.33). Association of TSC and WNK1 with hypertension was not observed. In conclusion, our study suggests the possible involvement of WNK4 in essential hypertension in a Japanese general population.     

Functional polymorphisms in <Emphasis Type="Italic">XRCC</Emphasis>-<Emphasis Type="Italic">1</Emphasis> and <Emphasis Type="Italic">APE</Emphasis>-<Emphasis Type="Italic">1</Emphasis> contribute to increased apoptosis and risk of ulcerative colitis

Objective  

The present study was designed to investigate the role of X-ray cross-complementing group 1 (XRCC1) and apurinic/apyrimidinic endonuclease 1 (APE1) polymorphisms in apoptosis and the risk of ulcerative colitis (UC).     

Redescription of <Emphasis Type="Italic">Lemuricola</Emphasis> (<Emphasis Type="Italic">Madoxyuris</Emphasis>) <Emphasis Type="Italic">bauchoti</Emphasis> (Nematoda,Oxyuridae) from <Emphasis Type="Italic">Lemur catta</Emphasis> in Madagascar

Lemuricola (Madoxyuris) bauchoti Chabaud, Brygoo et Petter, 1965 is redescribed from material collected from the ring-tailed lemur, Lemur catta, from the Beza Mahafaly Special Reserve in Madagascar using the scanning electron microscope. This is a new host record and the first oxyurid reported from the ring-tailed lemur. Previously, records of each species of the subgenus Madoxyuris have been restricted to a single host species, but the close relationship between these nematodes and their Strepsirrhini hosts will only be proven when additional records fill in the gaps in their distribution.     

Selective activity of extracts of <Emphasis Type="Italic">Margaritaria discoidea</Emphasis> and <Emphasis Type="Italic">Homalium africanum</Emphasis> on <Emphasis Type="Italic">Onchocerca ochengi</Emphasis>

Background  

The current treatment of onchocerciasis relies on the use of ivermectin which is only microfilaricidal and for which resistant parasite strains of veterinary importance are increasingly being detected. In the search for novel filaricides and alternative medicines, we investigated the selective activity of crude extracts of Margaritaria discoidea and Homalium africanum on Onchocerca ochengi, a model parasite for O. volvulus. These plants are used to treat the disease in North West Cameroon.     

<Emphasis Type="Italic">P</Emphasis>. <Emphasis Type="Italic">aeruginosa</Emphasis> Biofilms in CF Infection

Pseudomonas aeruginosa is an opportunistic pathogen of immunocompromised hosts. In cystic fibrosis (CF), P. aeruginosa causes acute and chronic lung infections that result in significant morbidity and mortality. P. aeruginosa possesses several traits that contribute to its ability to colonize and persist in acute and chronic infections. These include high resistance to antimicrobials, ability to form biofilms, plethora of virulence products, and metabolic versatility. In P. aeruginosa, a cell-to-cell communication process termed quorum sensing (QS) regulates many of these factors that contribute to its pathogenesis. Recent evidence suggests that the CF lung environment presents a specialized niche for P. aeruginosa. The relationship of P. aeruginosa QS, biofilm formation, and the CF lung environment is discussed.     

A role for accessory genes <Emphasis Type="Italic">rI.</Emphasis>-<Emphasis Type="Italic">1</Emphasis> and <Emphasis Type="Italic">rI.1</Emphasis> in the regulation of lysis inhibition by bacteriophage T4

Lysis inhibition (LIN) is a known feature of the T-even family of bacteriophages. Despite its historical role in the development of modern molecular genetics, many aspects of this phenomenon remain mostly unexplained. The key element of LIN is an interaction between two phage-encoded proteins, the T holin and the RI antiholin. This interaction is stabilized by RIII. In this report, we demonstrate the results of genetic experiments which suggest a synergistic action of two accessory proteins of bacteriophage T4, RI.-1, and RI.1 with RIII in the regulation of LIN.