Seasonal Abundance of Acanthamoeba rhysodes (Singh, 1952) (Protozoa: Gymnamoebia) in a Mangrove Litter-Soil Ecosystem of Gangetic-Estuary,India1,2

Acanthamoeba rhysodes has been found to be a predominant intertidal benthic gymnamoeba in the mangrove ecosystem of Sundarbans of lower deltaic Bengal, facing the Bay. The sampling zones under study were the highest high tide regions, with characteristic mangrove litter-soil, inundated twice per month during the highest ebb of spring tide. Population abundance of this species, both in its trophic and cystic forms in the three distinct seasonal periods of pre-monsoon (March to June), monsoon (July to October), and post-monsoon (November to February) has been surveyed for over two years. These seasonal periods affect the physico-chemical parameters of the habitat substrata, including temperature, pH, and salinity. It has been found that the overall number of organisms per gram of soil attains peak value during the monsoon period. This value comes down in post-monsoon samples and is the least in pre-monsoon ones.     

Fungal population in the atmosphere of Ismailia City

Fungal spore populations in the outdoor and indoor atmosphere of Ismailia have been studied during the period from March 1992 to May 1993. A total of 23 350 cfu and 73 species were recorded,Cladosporium cladosporioides, Aureobasidium pullulans andAspergillus flavus were the most abundant. The indoor and outdoor mycoflora showed marked quantitative and qualitative differences. In view of count, recorded species could be categorized into three groups as follows: (a) species showing higher counts in out- than indoor, (b) species showing the opposite trend i.e. lower counts in out-door than indoor, (c) species showing approximately equal counts in out- and indoor. Regarding seasonal periodicity, March and either September or October showed the highest count for both normal fungal flora (NFF) and opportunistic fungal flora (OFF). While January and July showed the lowest count of them both, May but not July was the lowest as for outdoor NFF.     

Actin and spectrin-like (Mr= 260–240 000) proteins in gregarines

In Gregarina blaberae a M_r = 47 000 and a M_r = 260–240 000 doublet polypeptides reacted in immunoblotting: i) with a polyclonal monospecific rabbit antibody to frog muscular actin, a monoclonal anti-actin antibody against chicken gizzard; and ii) with polyclonal and monoclonal antibodies to human erythrocyte β-spectrin, respectively. The M_r = 47 000 actin-like protein is associated with the ghost and a contractille cytoplasmic extract. The presence of an actin-like protein in Gregarina and Lecudina and its cellular distribution in the cortex indicated that the gliding movement might involve an actin-myosin system in contrast to previous studies. Immunofluorescence showed clear differences between the anterior part of Gregarina and Lecudina which illustrated the high cell polarity of these protozoa. The M_r = 260–240 000 doublet was detected in SDS-PAGE from G. blaberae trophozoite ghosts but not in the cytoplasmic extracts or in extracts from sexual stages, indicating that the presence of these spectrin-like proteins is stage-dependent. Visualization of the M_r = 260–240 000 by immunofluorescence showed clear species differences, with rings arranged perpendicular to the longitudinal narrow folds of G. blaberae, with longitudinal lines underlying the folds of L. pellucida and with lines separating the large folds of Selenidium pendula. The cellular distribution is consistent with a stabilizer function of the spectrin-like proteins in the scaffolding of the cortex of gregarines according to the high diversity of the cell-shape and the cell motility systems in gregarines. The presence of spectrin-like proteins in protozoa and particularly in parasites from primitive arthropods indicated that ancestral spectrin genes could the M_r = 260–240 000 form.     

Effects of vesicular-arbuscular mycorrhiza on Tagetes erecta and Zinnia elegans

 Seeds of Tagetes erecta and Zinnia elegans were planted in soil inoculated with the vesicular-arbuscular mycorrhizal fungus Glomus etunicatum. This procedure produced positive effects on both Tagetes and Zinnia compared with the control: faster flowering and an increased number of flowers. Shoot height, shoot and root dry weights and percentage infected root length were also measured. The reactions of these plants to mycorrhizal infection were shown to be independent of changes in the phosphorus, potassium and sodium contents of the plants. Accepted: 1 August 1995     

Structural investigations on the lipopolysaccharide isolated from Vibrio cholera,Inaba 569 B

On hydrolysis, the purified lipopolysaccharide (LPS) isolated from Vibrio cholera, Inaba 569 B, yielded glucose, mannose, a heptose behaving like d-glycero-l-manno-heptose and one behaving like d-glycero-l-gluco-heptose, 2-amino-2-deoxy-glucose, and glucuronic acid in the molar ratios of ～9:4:5:1:2:5. Studies on the LPS, the polysaccharide (PS), and carboxyl-reduced LPS showed that the PS has a branched structure, with (1→2)-linked mannopyranosyl and a heptopyranosyl, and (1→4)-linked glucopyranosyluronic and 2-amino-2-deoxyglucopyranosyl residues in the interior part of the molecule, and glucopyranosyl and heptopyranosyl residues as nonreducing end-groups.     

Macrophages rapidly transfer pathogens from lipid raft vacuoles to autophagosomes

Macrophages activate autophagy as an immediate response to Legionella pneumophila infection, but what marks the pathogen phagosome as a target for the autophagy machinery is not known. Because a variety of bacteria, parasites, viruses, and toxins that associate with the endoplasmic reticulum enter host cells by a cholesterol-dependent route, we tested the hypothesis that autophagy is triggered when microbes engage components of lipid raft domains. As the intracellular respiratory pathogen L. pneumophila or the extracellular uropathogen FimH(+) Escherichia coli entered macrophages by a cholesterol-sensitive mechanism, they immediatezly resided in vacuoles rich in glycosylphosphatidylinositol moieties and the autophagy enzyme Atg7. As expected for autophagosomes, the vacuoles sequentially acquired the endoplasmic reticulum protein BiP, the autophagy markers Atg8 and monodansyl-cadaverine, and the lysosomal protein LAMP-1. A robust macrophage response to the pathogens was cholesterol-dependent, since fewer Atg7-rich vacuoles were observed when macrophages were pretreated with methyl-beta-cyclodextrin or filipin. A model in which macrophages exploit autophagy to capture pathogens within the lipid raft pathway for antigen presentation prior to disposal in lysosomes is discussed.     

Identification of Lactic Acid Bacteria from Chili Bo, a Malaysian Food Ingredient

Ninety-two strains of lactic acid bacteria (LAB) were isolated from a Malaysian food ingredient, chili bo, stored for up to 25 days at 28°C with no benzoic acid (product A) or with 7,000 mg of benzoic acid kg⁻¹ (product B). The strains were divided into eight groups by traditional phenotypic tests. A total of 43 strains were selected for comparison of their sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) whole-cell protein patterns with a SDS-PAGE database of LAB. Isolates from product A were identified as Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus farciminis, Pediococcus acidilactici, Enterococcus faecalis, and Weissella confusa. Five strains belonging to clusters which could not be allocated to existing species by SDS-PAGE were further identified by 16S rRNA sequence comparison. One strain was distantly related to the Lactobacillus casei/Pediococcus group. Two strains were related to Weissella at the genus or species level. Two other strains did not belong to any previously described 16S rRNA group of LAB and occupied an intermediate position between the L. casei/Pediococcus group and the Weissella group and species of Carnobacterium. The latter two strains belong to the cluster of LAB that predominated in product B. The incidence of new species and subspecies of LAB in chili bo indicate the high probability of isolation of new LAB from certain Southeast Asian foods. None of the isolates exhibited bacteriocin activity against L. plantarum ATCC 14917 and LMG 17682.     

PYPAF7, a novel PYRIN-containing Apaf1-like protein that regulates activation of NF-kappa B and caspase-1-dependent cytokine processing

PYRIN-containing Apaf1-like proteins (PYPAFs) are members of the nucleotide-binding site/leucine-rich repeat (NBS/LRR) family of signal transduction proteins. We report here that PYPAF7 is a novel PYPAF protein that activates inflammatory signaling pathways. The expression of PYPAF7 is highly restricted to immune cells, and its gene maps to chromosome 19q13.4, a locus that contains a cluster of genes encoding numerous PYPAF family members. Co-expression of PYPAF7 with ASC results in the recruitment of PYPAF7 to distinct cytoplasmic loci and a potent synergistic activation of NF-kappa B. To identify other proteins involved in PYPAF7 and ASC signaling pathways, we performed a mammalian two-hybrid screen and identified pro-caspase-1 as a binding partner of ASC. Co-expression of PYPAF7 and ASC results in the synergistic activation of caspase-1 and a corresponding increase in secretion of interleukin-1 beta. In addition, PYPAF1 induces caspase-1-dependent cytokine processing when co-expressed with ASC. These findings indicate that PYPAF family members participate in inflammatory signaling by regulating the activation of NF-kappa B and cytokine processing.     

A new eimeriid (Apicomplexa) species from endangered Attwater's prairie chickens (Tympanuchus cupido attwateri) in Texas

The Attwater's prairie chicken (APC; Tympanuchus cupido attwateri Bendire, 1894) has been a federally listed endangered species since 1967. Several captive propagation programs consisting of small populations are being used to keep this species from extinction. Fecal samples were collected from APCs in April 2007 and again in August 2008 from 2 separate captive propagation facilities in Texas after clinical signs of coccidiosis were observed. One Eimeria species was observed (Eimeria attwateri), which we describe as a putative new species. Sporulated oocysts are ellipsoidal, 30.0 × 18.4 (27.4-31.3 × 16.0-22.4) μm. Oocysts have a smooth wall 0.7 μm thick and lack both a micropyle and oocyst residuum, but 1 ellipsoidal polar granule is present, 2.3 × 1.9 (2.1-2.4 × 1.7-2.0) μm. Sporocysts have a nipple-like Stieda body with a rounded opposite end and are 14.0 × 7.1 (10.2-16.8 × 6.0-9.2) μm. The sporocysts contain a sporocyst residuum usually consisting of 2-4 dispersed globules, and each sporozoite contains 2 large posterior spheroid refractile bodies 3.4 μm wide. Nucleotide sequence amplified from the 18S rDNA does not match any DNA sequence information for publicly available Eimeria species, and phylogenetic reconstructions place this species with other eimerians from Galliformes. The discovery of a potentially pathogenic species of Eimeria in captive APCs is of great importance, and managers should be aware of the potential devastating effect(s) this parasite could have on the APC conservation programs.     

Pathogenicity of Bacillus Strains to Cotton Seedlings and Their Effects on Some Biochemical Components of the Infected Seedlings

Pathogenicity of eight Bacillus strains to seedlings of four cotton cultivars was evaluated under greenhouse conditions. Each of the tested cultivars was individually treated with powdered inoculum of each bacterial strain. Untreated seeds were planted as control treatments in autoclaved soil. Effects of the tested strains on levels and activities of some biochemical components of the infected seedlings were also assayed. The biochemical components included total soluble sugars, total soluble proteins, total free amino acids, peroxidase, polyphenol oxidase, phenols, and lipid peroxidation. ANOVA showed that Bacillus strain (B) was a very highly significant source of variation in damping-off and dry weight. Cotton cultivar (V) was a nonsignificant source of variation in damping-off while it was a significant source of variation in dry weight. B × V interaction was a significant source of variation in damping- off and a nonsignificant source of variation in dry weight. Bacillus strain was the most important source of variation as it accounted for 59.36 and 64.99% of the explained (model) variation in damping-off and dry weight, respectively. The lack of significant correlation between levels and activities of the assayed biochemical components and incidence of damping-off clearly demonstrated that these biochemical components were not involved in the pathogenicity of the tested strains. Therefore, it was hypothesized that the pathogenicity of the tested strains could be due to the effect of cell wall degrading enzymes of pathogenic toxins. Based on the results of the present study, Bacillus strains should be considered in studying the etiology of cotton seedling damping-off.