QoI Resistance and Mitochondrial Genetic Structure of Zymoseptoria tritici in Morocco.

In total, 230 single-conidial isolates of the fungal wheat pathogen Zymoseptoria tritici (formerly Septoria tritici, teleomorph: Mycosphaerella graminicola) were sampled in Morocco in 2008 and 2010 to assess resistance against quinone outside inhibitors (QoIs), a widely used group of fungicides in wheat pest management. All 134 isolates sampled in 2008 were QoI sensitive. In contrast, 9 of the 96 isolates from the 2010 collection were resistant, suggesting a recent emergence of the resistance. Mitochondrial (mt)DNA-sequence analyses identified four haplotypes among the resistant isolates. Wright's F statistics (FST) analyses from mtDNA sequences revealed a shallow population structure of Z. tritici within Morocco and a substantial asymmetric gene flow from Europe into Morocco. A phylogenetic reconstruction including Moroccan and European isolates clustered the haplotypes regardless of their geographic origin. The four Moroccan QoI-resistant mitochondrial haplotypes clustered in two distinct clades in the tree topology, suggesting at least two independent origins of the resistance. This study reported, for the first time, the occurrence of QoI-resistant genotypes of Z. tritici in Morocco. Our findings are consistent with the hypothesis that QoI resistance emerged very recently through parallel genetic adaptation in Morocco, although gene flow from Europe cannot be excluded.

Wheat Mycosphaerella graminicola interactions in Morocco.

Mycosphaerella graminicola is nowadays one of the most important foliar pathogens on wheat crops worldwide and more specifically in Morocco. The interactions of eight monoconidial isolates of this fungus, sampled in different regions of Morocco, with 3 Moroccan wheat cultivars (Massira, Amal and Arrihan) differing in their resistance level to the pathogen, were studied using artificial inoculations in the greenhouse. Disease notations (percentage of third leaf areas covered by lesions bearing pycnidia) at 21 days post inoculation revealed significant differences among the different isolate-cultivar combinations. Most isolates expressed pathogenicity profiles in accordance with the resistance levels of the cultivars studied. However, T01701 showed a similar pathogenicity level on the three cultivars and T01718 induced more disease on the moderately resistant cv. Amal compared to the susceptible cv. Massira and the resistant cv. Arrihan, respectively. Furthermore, the infection process of the isolate T01757 was investigated at 4, 8, 12, 16 and 21 days post-inoculation. This isolate exhibited a disease gradient (65%, 24% and 5%) which negatively correlated with the resistance levels of the cultivars. No significant differences were obtained regarding the rates of spore germination and leaf penetration events. However, rates of mesophyll colonization positively correlated with the disease levels scored on the cultivars. This study supports the presence of strain-cultivar interactions between wheat and M. graminicola in Morocco and confirms the importance of mesophyll colonization in disease establishment and extension.

Ozonation of endogenous residue and active biomass from a synthetic activated sludge.

Coupling the activated sludge and the ozonation processes is an efficient, although expensive, solution for sludge reduction. A better knowledge of the mechanisms involved in the degradation of various sludge fractions by ozone is needed to optimize the coupled process. The objectives of this study were to determine the biodegradability of ozone-solubilized endogenous residue, the action of ozone on the active biomass and the solubilization yield of these two main sludge fractions. Batch tests were conducted with slug input of ozone stock solution into fresh or aerobically digested synthetic sludge. Biodegradability of the solubilized endogenous residue was increased by ozonation by up to 0.27 g BOD5/g CODi. Ozone caused biomass lysis, as opposed to an increase in maintenance needs, as shown by a correlation between the decrease in microbial activity and viability. Lysis caused by ozonation was associated with a solubilization of 20% of the lyzed cell COD mass. Solubilization yields were of 9.6 and of 1.9 to 3.6 g COD/g O3 for fresh and aerobically digested sludge, respectively. Design of sludge ozonation processes should account for the variability between the solubilization yield and biodegradability of the various sludge fractions.

Detection of strobilurin-resistant isolates of Mycosphaerella graminicola in Morocco.

Septoria tritici blotch caused by Mycosphaerella graminicola (anamorph: Septoria tritici) is nowadays one of the most frequently occurring diseases on both bread and durum wheat crops. Two hundred and thirty isolates of the fungus were sampled from six distinct wheat-producing regions of Morocco in order to investigate the resistance of M. graminicola to strobilurins in this country, where this fungicide class is increasingly used in wheat-pest management. A subset of 134 isolates was first collected in 2008 from Meknes-Tafilalet, Tadla-Azilal, Gharb and Chaouia. Furthermore, 96 additional isolates were sampled in 2010 from the fourth regions investigated in 2008 plus Fes-Boulmane and Doukkala-Abda. Sensitivity or resistance within the isolates were determined by screening the G143A cytochrome b substitution conferring resistance. We used a mismatch amplification mutation assay allowing the amplification of either G143 (sensitive) or A143 (resistant) allele. All the 2008 isolates were found to be sensitive since they carry the wild-type allele G143. However, 9 (9%) out of the 2010 isolates were found to contain the resistant allele A143 and therefore to be resistant. Four of them were from Gharb and five from Fes-Boulmane. This study highlighted for the first time the occurrence of strobilurin-resistant isolates of M. graminicola in Morocco. Further genetic investigations should determine if the resistant isolates emerged independently in Morocco or traveled by wind-migration from Europe.

Both mating types of the wheat pathogen Mycosphaerella graminicola are present in Morocco.

Septoria tritici blotch caused by the heterothallic ascomycete Mycosphaerella graminicola is one of the most currently damaging diseases on wheat crops worldwide. So far, no information was reported about the status of sexual reproduction of this pathogen under Moroccan conditions. We investigated here for the first time the occurrence of the two mating types (MAT1-1 and MAT1-2) of M. graminicola in Morocco by sampling 141 single-conidial isolates from 4 important wheat producing regions (Gharb, Saïs, Chaouia and Tadla). The mating type of each isolate was determined by amplification with multiplex PCR of a partial sequence from the corresponding idiomorph. Overall, 43% out of the assessed isolates were MAT1-1 and 57 % were MAT1-2. Both mating types were identified within the 3 sampled regions Gharb, Saïs and Chaouia, but not in Tadla, where only MAT1-2 isolates were found. The presence of the two mating types highlighted here offers a suitable genetic condition for M. graminicola to occur sexual reproduction in Morocco. The potential of sexual recombination will be examined by the study of mating type frequencies using a large sample size as well as by searching and quantification of pseudothecia in the field.

Lanreotide inhibits human jejunal secretion induced by prostaglandin E1 in healthy volunteers.

1. Somatostatin inhibits hormonal secretions in the gastrointestinal tract. Somatostatin analogues are used in the treatment of VIPome-related watery diarrhoea. In addition, more than 10% of patients with AIDS suffer from diarrhoea likely due to the increased intestinal secretion of water and ions. However, the direct effect of somatostatin on the flux of water and ions in the intestine has not been, so far, analyzed in vivo. The aim of the present study was to evaluate the effect of lanreotide, a somatostatin analogue, on the movements of water and ions in the jejunum in man. 2. Accordingly, 10 healthy volunteers (age 18-35 years, mean 27) and two patients with AIDS (26 and 33 years) suffering from water diarrhoea (> 800 ml day-1) underwent intestinal perfusion using a four lumen tube with proximal occluding balloon. The segment tested was 25 cm long. The jejunum was infused by an isotonic control saline solution containing polyethylene glycol (PEG) as nonabsorbable marker. Basal jejunal secretions were measured in all subjects. Prostaglandin E1 (PGE1) was administered intraluminally to stimulate jejunal secretion in healthy volunteers. The effect of intravenous lanreotide on the jejunal PGE1-induced secretions of water and electrolytes was analysed in healthy subjects and on the basal secretions in AIDS patients. Each period was analyzed on the basis of three (10 min) successive intestinal juice collections after 20-30 min equilibration time. The antisecretory effect of lanreotide was evaluated in each subject as the difference between fluxes compared to the control period. 3. In healthy volunteers, PGE1 induced secretion of H2O, Na+, K+ and Cl- in the jejunum and lanreotide reduced significantly PGE1-induced response. In both AIDS patients basal fluxes of water and ions were reduced by lanreotide in a dose-dependent manner. 4. Somatostatin can reduce stimulated-jejunal secretion of ions and water in normal subjects and may improve water diarrhoea in AIDS patients.

Antacid activity of calcium carbonate and hydrotalcite tablets. Comparison between in vitro evaluation using the "artificial stomach-duodenum" model and in vivo pH-metry in healthy volunteers.

Antacid activity of calcium carbonate (CAM, Rennie) and of hydrotalcite (HYD) containing tablets has been assessed in vitro using computer-controlled "artificial stomach-duodenum" model, including or not a piece of hog gastric mucosa in the gastric reservoir, and simulating the constant flux system or the normal gastroduodenal flux regulation. The data obtained under the latter condition were compared to those obtained in vivo by pH-metry in 12 healthy volunteers, in response to one administration of 2 tablets. The theoretical maximal capacity was similar when 1 tablet of CAM or of HYD was added to the gastric contents, including or not a piece of gastric mucosa, close to 95 H+ mmol. The reduction of acid load penetrating into the duodenum and the duodenal pH were of the same magnitude in response to both antacids. When normal gastroduodenal flux regulation was simulated, a dose-response curve, constructed by 1, 2 or 3 tablets, resulted in the same antacid characteristics in response to both antacids. The maximal gastric and the mean duodenal pH values obtained with CAM were, however, higher than with HYD, corresponding to a greater neutralizing activity developed by CAM than by HYD. The comparison between in vivo administration of two tablets of each antacid and the in vitro model simulating normal gastroduodenal flux regulation in response to the addition of two tablets resulted in similar data. The maximal pH values obtained in in vivo assays were slightly lower than in vitro, depending on the ratio of antacid amount to gastric acid content, well established in in vitro conditions and unknown in in vivo situations.(ABSTRACT TRUNCATED AT 250 WORDS)

A monoclonal antibody directed to sulfatide inhibits the binding of human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein to macrophages but not their infection by the virus.

We show here that human immunodeficiency virus (HIV) envelope glycoproteins (gp160/gp120) bind to sulfatide and galactosyl ceramide. By immunofluorescence labeling with monoclonal antibody (mAb) A2B5, specific for ganglioside/sulfatide, we detect negatively charged glycolipids on CD4+ cells of the macrophage lineage and lymphocytes. Labeling of monocyte-derived macrophages (MDM) with mAb A2B5 was reproducibly found in 29 healthy donors, independently of the culture method and duration up to 11 days. The binding of the mAb to neuraminidase-treated MDM was unchanged relative to control cells, but mAb binding decreased after arylsulfatase treatment, which indicates that MDM membrane sulfatide is its major ligand. Preincubating MDM with the mAb partially (40-60%) but significantly inhibited the binding of HIV-1LAI radiolabeled recombinant gp160 to the cells. Similarly, the mAb entailed limited (32%) but significant inhibition of gp160 binding to cells of the monocytic U937 line but not to lymphoid CEM cells. However, mAb A2B5 did not inhibit the infection of CEM nor of U937 cells by HIV-1LAI strain, nor of MDM by monocytotropic HIV-1BaL. Thus, although sulfatide may be involved in the binding of HIV env glycoprotein to MDM or monocytic U937 cells, this does not play a significant role in HIV infection of these CD4+ cells.

[Comparative efficacy of lansoprazole and omeprazole on the intragastric pH measured over a period of 24 hours and on the basal]. / Efficacité comparée du lansoprazole et de l'oméprazole sur le pH intragastrique mesuré sur 24 heures et sur le débit acide basal chez 9 malades atteints de syndrome de Zollinger-Ellison.

OBJECTIVES: This paper aimed at evaluating the comparative efficacy of lansoprazole and omeprazole in reducing gastric acid secretion in patients suffering from Zollinger-Ellison syndrome. METHODS: Nine patients with non-resected gastrinoma(s) an previously well controlled by omeprazole (mean dosage 75 +/- 12.4 (SEM) mg/day; extremes: 20-160 mg/day) underwent 24-hour intragastric pH-metry, baseline acid output before next dosing and serum gastrin dosages, receiving their usual therapy and thereafter lansoprazole at a weight equivalent posology (mean dosage 81.6 +/- 12.5 (SEM) mg/day; extremes: 30-165 mg/day). RESULTS: Lansoprazole maintained intragastric pH and basal acid output at therapeutic levels, but a discrete reacidification, that deserves confirmation on a larger group of patients, was observed between the meals. CONCLUSIONS: The possible long-term benefit of this phenomenon, especially on gastrinemia and the fundic ECL-cells density and gastric bacterial content, remains to be evaluated.

Long-term treatment with octreotide in patients with the Zollinger-Ellison syndrome.

This study reports the effects of 4 and 5-year treatment with octreotide (200 micrograms sc bid) in the Zollinger-Ellison syndrome (ZES). No symptoms related to acid hypersecretion were observed in the four patients throughout the study, and upper GI endoscopy was normal. Basal acid output (BAO) measured 12 h after injection, was below 10 mmol h-1 in three to four patients and previous ranitidine treatment was discontinued. In the fourth case (pretreatment BAO value: 115 mmol h-1), BAO progressively decreased to 42 mmol h-1 after 5 years of octreotide treatment. At the end of the study, serum gastrin levels were 58.5% (30-68) of the pretreatment values and two patients had normal gastrin levels. Peak acid output (PAO) decreased markedly after 2, 4 and 5 years, by 68% (35-89) suggesting that octreotide had exerted an antitrophic effect on parietal cell mass. Diffuse hyperplasia of fundic argyrophil cells present in two patients before octreotide, decreased during the treatment. Mean argyrophil cell density for all patients was not significantly modified. Antral gastrin-cell density was in the normal range. No long-term side effect of octreotide treatment was observed. Although octreotide may not be considered as a substitute for benzimidazoles in the treatment of ZES, its specific properties may be of therapeutic benefit in some ZES patients.

Lectin-carbohydrate interactions and infectivity of human immunodeficiency virus type 1 (HIV-1).

The aim of this study was to determine whether mannosyl-specific lectins, especially Concanavalin A (ConA), may bridge HIV-1 env glycoproteins to cell membranes to increase virus binding to its targets, and to what extent this lectin-carbohydrate interaction can modify HIV-1 infectivity for monocytic compared with lymphoid cells. Monocytic U937 and lymphoid CEM cells, which both express surface mannose, were utilized. Whether first incubated with env glycoprotein or with the cells, lectins bound both to the cells and to radiolabeled recombinant gp160 (rgp160). Thus, they enhanced rgp160 adsorption to the cells in a methyl-alpha-mannose inhibitable manner. ConA did not appear to bind to the V1 domain of CD4 at the U937 cell surface since Leu3a binding was not blocked in the presence of ConA, nor was recombinant CD4 retained on a ConA-agarose affinity matrix. Moreover, enhanced rgp160 binding to the cells was CD4 independent, since it was not modified by preincubating the cells with Leu3a. Finally, ConA did not inhibit the binding of CD4-IgG3 chimeric molecules to virions immobilized on nitrocellulose membrane, which argues against the possibility that it interferes with the interaction of gp120 and CD4. However, both when incubated with the virus or with the cells and despite mediating enhanced binding of env glycoprotein, ConA neutralized HIV-1 infectivity for monocytic U937 as well as for lymphoid CEM cells. In this respect, ConA behaves like neutralizing antibodies which do not interfere with CD4 binding of gp120 but rather with some later event that leads to virus entry. These findings obtained with plant lectins may be of relevance in vivo, inasmuch as endogenous mannosyl-binding proteins, which are known to function as opsonins, have been reported to inhibit in vitro infection by HIV-1.