Uncommon and fatal case of cystoisosporiasis in a non HIV-immunosuppressed patient from a non-endemic country

Cystoisospora belli (previously known as Isospora belli) is a tropical coccidian parasite sometimes leading to severe diarrhea in immunocompromised patients. Here we describe a fatal case of cystoisosporiasis in a non HIV-immunocompromised 71-year-old female with no recent travel history. Infection was either latent or potentially caused by the consumption of contaminated imported food from Asia. Diagnosis was made by microscopical detection of numerous C. belli oocysts in stools without specific staining. Treatment with TMP-SMZ slightly improved diarrhea within 3 days, but dehydration subsequently led to acute decompensated heart failure and a fatal evolution. This report illustrates the possibility of severe cystoisosporiasis in non HIV-immunocompromised patients in a non-endemic country and highlights the risk of transmission through imported contaminated food consumption.     

Small-grained wild grasses as staple food at the 23 000-year-old site of Ohalo II,Israel

More than 16 000 grains of small-grained grasses were retrieved at Ohalo II, a submerged 23 000-year-old site on the shore of the Sea of Galilee, Israel. The grains were part of a very large archaeobotanical assemblage, unique for its period and region, as well as its exceptionally good preservation. This paper proposes that these grains were a staple food at Ohalo II, based on several lines of evidence: 1. the large number of grains found; 2. the fact that all grains were fully mature; and 3. ethnographic parallels for the use of small-grained grasses in hunter-gatherers’ societies as well as among present-day agriculturalists.     

Cloning of a rat gene encoding the histo-blood group A enzyme. Tissue expression of the gene and of the A and B antigens.

The complete coding sequence of a BDIX rat gene homologous to the human ABO gene was determined. Identification of the exon-intron boundaries, obtained by comparison of the coding sequence with rat genomic sequences from data banks, revealed that the rat gene structure is identical to that of the human ABO gene. It localizes to rat chromosome 3 (q11-q12), a region homologous to human 9q34. Phylogenetic analysis of a set of sequences available for the various members of the same gene family confirmed that the rat sequence belongs to the ABO gene cluster. The cDNA was transfected in CHO cells already stably transfected with an alpha1,2fucosyltransferase in order to express H oligosaccharide acceptors. Analysis of the transfectants by flow cytometry indicated that A but not B epitopes were synthesized. Direct assay of the enzyme activity using 2' fucosyllactose as acceptor confirmed the strong UDP-GalNAc:Fucalpha1,2GalalphaGalNAc transferase (Atransferase) activity of the enzyme product and allowed detection of a small UDP-Gal:Fucalpha1,2GalalphaGal transferase (B transferase) activity. The presence of the mRNA and of the A and B antigens was searched in various BDIX rat tissues. There was a general good concordance between the presence of the mRNA and that of the A antigen. Tissue distributions of the A and B antigens in the homozygous BDIX rat strain were largely different, indicating that these antigens cannot be synthesized by alleles of the same gene in this rat inbred strain.     

Neutralizing Antibodies in Sera from Macaques Immunized with Attenuated Simian Immunodeficiency Virus

Infection with attenuated simian immunodeficiency virus (SIV) in rhesus macaques has been shown to raise antibodies capable of neutralizing an animal challenge stock of primary SIVmac251 in CEMx174 cells that correlate with resistance to infection after experimental challenge with this virulent virus (M. S. Wyand, K. H. Manson, M. Garcia-Moll, D. C. Montefiori, and R. C. Desrosiers, J. Virol. 70:3724–3733, 1996). Here we show that these neutralizing antibodies are not detected in human and rhesus peripheral blood mononuclear cells (PBMC). In addition, neutralization of primary SIVmac251 in human and rhesus PBMC was rarely detected with plasma samples from a similar group of animals that had been infected either with SIVmac239Δnef for 1.5 years or with SIVmac239Δ3 for 3.2 years, although low-level neutralization was detected in CEMx174 cells. Potent neutralization was detected in CEMx174 cells when the latter plasma samples were assessed with laboratory-adapted SIVmac251. In contrast to primary SIVmac251, laboratory-adapted SIVmac251 did not replicate in human and rhesus PBMC despite its ability to utilize CCR5, Bonzo/STRL33, and BOB/gpr15 as coreceptors for virus entry. These results illustrate the importance of virus passage history and the choice of indicator cells for making assessments of neutralizing antibodies to lentiviruses such as SIV. They also demonstrate that primary SIVmac251 is less sensitive to neutralization in human and rhesus PBMC than it is in established cell lines. Results obtained in PBMC did not support a role for neutralizing antibodies as a mechanism of protection in animals immunized with attenuated SIV and challenged with primary SIVmac251.     

Inhibition of colicin synthesis by the antibiotic globomycin

Wolinella succinogenes can grow by anaerobic respiration with fumarate or polysulfide as the terminal electron acceptor, and H₂ or formate as the electron donor. A ΔhydABC mutant lacking the hydrogenase structural genes did not grow with H₂ and either fumarate or polysulfide. In contrast to the wild-type strain, the mutant grown with fumarate and with formate instead of H₂ did not catalyze the reduction of fumarate, polysulfide, dimethylnaphthoquinone, or benzyl viologen by H₂. Growth and enzymic activities were restored upon integration of a plasmid carrying hydABC into the genome of the ΔhydABC mutant. The ΔhydABC mutant was complemented with hydABC operons modified by artificial stop codons in hydA (StopA) or at the 5′-end of hydC (StopC). The StopC mutant lacked HydC, and the hydrophobic C-terminus of HydA was missing in the hydrogenase of the StopA mutant. The two mutants catalyzed benzyl viologen reduction by H₂. The enzyme activity was located in the membrane of the mutants. A mutant with both modifications (StopAC) contained the activity in the periplasm. The three mutants did not grow with H₂ and either fumarate or polysulfide, and did not catalyze dimethylnaphthoquinone reduction by H₂. We conclude that the same hydrogenase serves in the anaerobic respiration with fumarate and with polysulfide. HydC and the C-terminus of HydA appear to be required for both routes of electron transport and for dimethylnaphthoquinone reduction by H₂. The hydrogenase is anchored in the membrane by HydC and by the C-terminus of HydA. The catalytic subunit HydB is oriented towards the periplasmic side of the membrane. Received: 29 December 1997 / Accepted: 6 March 1998     

Outer Membrane of Avian Myeloblastosis Virus

Guinea pigs immunized intracerebrally with avian myeloblastosis virus (AMV) produced antiserum which reacted with intact virus particles in complement fixation. The antigen in question appeared to be located on the surface of the virion and could be distinguished from the type-specific virus envelope and the group-specific internal antigens of chicken leukosis-sarcoma viruses (ChiLSV). The material could be isolated by sequential treatments of AMV with bromelin, Tween 20, and freeze-thawing, and could be purified by differential centrifugation. Electron microscopy analysis indicated the presence of a component resembling the outer membrane of the particle. The antigenic determinant was designated virus membrane antigen (Vm). Further analyses revealed the presence of protein, lipid, and carbohydrate in a material having a molecular weight of about 6,000 as determined by sodium dodecyl sulfate gel electrophoresis. Serological studies suggested that the outer membranes of AMV and other ChiLSV are represented mainly by host cellular material.     

In vitro virulence characteristics of rare serovars of <Emphasis Type="Italic">Salmonella enterica</Emphasis> isolated from sand lizards (<Emphasis Type="Italic">Lacerta agilis</Emphasis> L.)

The aim of this study was to estimate virulence potential of Salmonella enterica strains colonizing the gut of free-living sand lizards (Lacerta agilis L.). The strains belonged to three Salmonella serovars: Abony, Schleissheim, and Telhashomer. Adhesion and invasion abilities of the strains were determined in quantitative assays using the gentamicin protection method. Induction of apoptosis was assessed using HeLa cell monolayers. PCR assays were used for detection of 26 virulence genes localised within mobile elements: pathogenicity islands, virulence plasmids, and prophage sequences. In vitro studies revealed that all strains had adhesion and invasion abilities to human epithelial cells. The isolates were cytotoxic and induced apoptosis of the cells. The serovars differed in the number of virulence-associated genes: up to 18 genes were present in Salmonella Schleissheim, 17 in Salmonella Abony, whereas as few as six genes were found in Salmonella Telhashomer. Generally, Salmonella Abony and Salmonella Schleissheim did not differ much in gene content connected with the presence SPI-1 to -5. All of the strains lacked genes localised within bacteriophages and plasmids. The presence of virulence-associated genes and in vitro pathogenicity assays suggest that Salmonella sp. strains originating from autochthonous, free-living lizards can potentially infect and cause disease in humans.     

Engineering of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> to utilize xylan as a sole carbohydrate source by co-expression of an endoxylanase,xylosidase and a bacterial xylose isomerase

Xylan represents a major component of lignocellulosic biomass, and its utilization by Saccharomyces cerevisiae is crucial for the cost effective production of ethanol from plant biomass. A recombinant xylan-degrading and xylose-assimilating Saccharomyces cerevisiae strain was engineered by co-expression of the xylanase (xyn2) of Trichoderma reesei, the xylosidase (xlnD) of Aspergillus niger, the Scheffersomyces stipitis xylulose kinase (xyl3) together with the codon-optimized xylose isomerase (xylA) from Bacteroides thetaiotaomicron. Under aerobic conditions, the recombinant strain displayed a complete respiratory mode, resulting in higher yeast biomass production and consequently higher enzyme production during growth on xylose as carbohydrate source. Under oxygen limitation, the strain produced ethanol from xylose at a maximum theoretical yield of ~90 %. This study is one of only a few that demonstrates the construction of a S. cerevisiae strain capable of growth on xylan as sole carbohydrate source by means of recombinant enzymes.