Cellular and genetic responses to mesoderm induction in Xenopus

Mesodermal cell differentiation begins in response to an inductive interaction early in frog development. In parallel with the recent finding that certain peptide growth factors can induce mesoderm, early cellular and genetic responses to the induction have been discovered. I review here recent work on these responses, work that aims to understand how cells respond to inducers to form the complex pattern of the vertebrate mesoderm.     

Cefepime/amikacin in the empirical antibacterial therapy for patients with hemoblastosis of different forms]

The results of the use of cefepime (Maxipime) combination with amikacin vs ceftriaxon combination with amikacin in the treatment of 80 patients with different forms of hemoblastosis are presented. Severe infectious complications in the patients were associated with prolonged and deep neutropenia during inductive or antirelapsing chemotherapy. All the patients in the trial were from the group of high risk of infectious complications with the blood neutrophil count under 100 cells/microliter. The duration of neutropenia averaged 12 days (7 to 15). The average period of the treatment with cefepime and amikacin equaled to 13 days (8 to 16). The treatment with cefepime + amikacin was successful in 38 out of 40 patients (95%). The average period of the treatment with ceftriaxon and amikacin equaled to 14 days (7 to 18). The efficacy of the treatment with ceftriaxon + amikacin was 60% (24 patients out of 40).     

New gene assignments using a complete, characterized sheep-hamster somatic cell hybrid panel

The generation and characterization of new sheep-hamster cell hybrids is reported from the fusion of sheep white blood cells with six different hamster auxotrophs. Selection from these and previously generated cell hybrids has led to the production of a panel of 30 hybrids covering the complete sheep genome of 28 chromosomes. Over half of the cell hybrids in this panel contain single sheep chromosomes. By complementation, the following new assignments have been made using the panel: phosphoribosyl N-formylglycinamide amidotransferase (PRFGA) to sheep chromosome (chr) 11; adenylosuccinate synthetase (ADSS) to sheep chr 12; adenylosuccinate lyase (ADSL) to sheep chr 3q; 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMGCS) to sheep chr 16; dihydrofolate reductase (DHFR) to sheep chr 5; and adenine phosphoribosyltransferase (APRT) to sheep chr 14. The gene phosphoribosylaminoinidazole-carboxamide formyltransferase/Inosinicase (PRACFT) has now been regionally assigned to chr 2q. By isozyme analysis, phosphogluconate dehydrogenase (PGD) was assigned to sheep chr 12, anchoring the sheep syntenic group U1 to this chromosome, and mannose phosphate isomerase (MPI) was assigned to sheep chr 18. Furthermore, the chromosomal assignment of 110 microsatellites was confirmed using this cell panel.     

Host-Parasite Interactions and Purifying Selection in a Microsporidian Parasite of Honey Bees

To clarify the mechanisms of Nosema ceranae parasitism, we deep-sequenced both honey bee host and parasite mRNAs throughout a complete 6-day infection cycle. By time-series analysis, 1122 parasite genes were significantly differently expressed during the reproduction cycle, clustering into 4 expression patterns. We found reactive mitochondrial oxygen species modulator 1 of the host to be significantly down regulated during the entire infection period. Our data support the hypothesis that apoptosis of honey bee cells was suppressed during infection. We further analyzed genome-wide genetic diversity of this parasite by comparing samples collected from the same site in 2007 and 2013. The number of SNP positions per gene and the proportion of non-synonymous substitutions per gene were significantly reduced over this time period, suggesting purifying selection on the parasite genome and supporting the hypothesis that a subset of N. ceranae strains might be dominating infection.     

Temperature influences the expression of fimbriae and flagella in <Emphasis Type="Italic">Hafnia alvei</Emphasis> strains: an immunofluorescence study

Hafnia alvei, a Gram negative bacillus related to the Enterobacteriaceae family, is considered an opportunistic pathogen of several animal species and humans. In this communication, we describe fimbrial-like structures from different strains of H. alvei that cannot be easily ascribed to any of the previously reported fimbrial types in this species (type I or type III). Polymerase chain reaction (PCR) and immunofluorescence assays were carried out to study fimbriae and flagella in H. alvei strains isolated from different sources. No correlation between the results obtained by PCR and those obtained by phenotypic methods were found, and the antibodies used gave cross or different recognition patterns of the surface structures present in these strains. We report as well that strain and growth temperature influence fimbriation and expression of flagella in human and animal isolates of H. alvei. This study also indicates that the absence of fimbriae have a significant positive influence on the initial adhesion of H. alvei to human epithelial cells.