High effectiveness of the method with cefpirome in detection of extended-spectrum beta-lactamases in different species of gram-negative bacilli

Gram-negative bacilli were examined for ESBL production by using four methods: double-disc synergy diffusion test (DDST), and three tests of combined discs with cefpodoxime, ceftazidime and cefotaxime alone and the same cephalosporins with clavulanic acid. Strains determined as ESBL-negative with all these tests were examined by using fifth method with cefpirome. 47,5% from 178 negative in other methods strains, appeared ESBL-positive in this test. The examined strains belonged to 16 different species. Most of them were Enterobacter cloaceae, Serratia marcescens, Pseudomonas aeruginosa and Acinetobacter baumanii. It seems that the combined discs method with cefpirome may be usefull for phenotypic detection of ESBL producing bacteria also in the case of strains where ESBL production is camouflaged with derepressed chromosomal AmpC beta-lactamases.     

Micronutrients and macronutrients and parameters of antioxidative ability in saliva of women

There were two aims of the present study: (1) to evaluate changes of superoxide dismutase (SOD) activity and total antioxidative status measured as the ferric reducing ability of plasma (FRAP) concentration in saliva of pregnant women during the first, second, and third trimesters of singleton uncomplicated pregnancy and (2) to assess possible relations among SOD, FRAP, and intake of macronutrients and micronutrients in daily nutritional rations (DNRs) during pregnancy. Forty pregnant women aged 27.1+/-5.4 yr (examined group) and 40 healthy women (the control group) were recruited for this study. The relationship between FRAP and SOD in saliva and the intake of macronutrients (proteins, carbohydrates, total fat, saturated fatty acid, monounsaturated fatty acids, polyunsaturated fatty acids), minerals (Na, K, Ca, P, Mg, Fe, Zn, Cu, Mn), and vitamins (A, C, E, B1, B2, B6, PP) in DNR was evaluated by clustering analysis with Ward's grouping method. During pregnancy, FRAP and SOD values were lower than in the controls, but only for FRAP were the differences statistically significant (p < 0.001). For the whole pregnancy period, cluster analysis identified two major clusters for which the differentiating variables were SOD and retinoids intake, but different patterns for each trimester of pregnancy were revealed. The following were concluded: (1) FRAP values were the lowest in the second trimester. It suggests that in this trimester of uncomplicated pregnancy, women might be not fully adapted to increased demands for antioxidative mechanisms. (2) Cluster analysis showed that there were no statistical relationships between the intake of micronutrients and macronutrients in DNRs and the SOD or FRAP level in the saliva of pregnant women.     

Detection of bacteriophage infection and prophage induction in bacterial cultures by means of electric DNA chips

Infections of bacterial cultures by bacteriophages are common and serious problems in many biotechnological laboratories and factories. A method for specific, quantitative, and quick detection of phage contamination, based on the use of electric DNA chip is described here. Different phages of Escherichia coli and Bacillus subtilis were analyzed. Phage DNA was isolated from bacterial culture samples and detected by combination of bead-based sandwich hybridization with enzyme-labeled probes and detection of the enzymatic product using silicon chips. The assay resulted in specific signals from all four tested phages without significant background. Although high sensitivity was achieved in 4h assay time, a useful level of sensitivity (10(7)-10(8) phages) is achievable within 25 min. A multiplex DNA chip technique involving a mixture of probes allows for detection of various types of phages in one sample. These analyses confirmed the specificity of the assay.     

Plant signalling peptides: some recent developments.

The subject of this review is plant signalling peptides, peptides of a new generation which regulate growth, differentiation, and other plant physiological functions. These peptides include systemin, the phytosulfokines (PSKs), ENOD40, CLAVATA3, Locus-S, POLARIS, IDA, and ROT4. On the basis of literature data and our own results we discuss their structure, biological properties, and structure/biological function relationship, especially for the more studied systemin and PSK-alpha.     

Identification and origin of the germline stem cells as revealed by the expression of nanos-related gene in planarians

The planarian's remarkable regenerative ability is thought to be supported by the stem cells (neoblasts) found throughout its body. Here we report the identification of a subpopulation of neoblasts, which was revealed by the expression of the nanos-related gene of the planarian Dugesia japonica, termed Djnos. Djnos-expressing cells in the asexual planarian were distributed to the prospective ovary or testes forming region in the sexual planarian. During sexualization, Djnos-expressing cells produce germ cells, suggesting that in the asexual state these cells were kept as germline stem cells for the oogonia and spermatogonia. Interestingly, the germline stem cells were indistinguishable from the neoblasts by morphology and X-ray sensitivity and did not seem to contribute to the regeneration at all. Germline stem cells initially appear in the growing infant planarian, suggesting that germline stem cells are separated from somatic stem cells in the planarian. Thus, planarian neoblasts can be classified into two groups; somatic stem cells for regeneration and tissue renewal, and germline stem cells for production of germ cells during sexualization. However, Djnos-positive cells appeared in the newly formed trunk region from the head piece, suggesting that somatic stem cells can convert to germline stem cells.     

Mammalian Target of Rapamycin Complex 1 (mTORC1) and 2 (mTORC2) Control the Dendritic Arbor Morphology of Hippocampal Neurons

Dendrites are the main site of information input into neurons. Their development is a multistep process controlled by mammalian target of rapamycin (mTOR) among other proteins. mTOR is a serine/threonine protein kinase that forms two functionally distinct complexes in mammalian cells: mTORC1 and mTORC2. However, the one that contributes to mammalian neuron development remains unknown. This work used short hairpin RNA against Raptor and Rictor, unique components of mTORC1 and mTORC2, respectively, to dissect mTORC involvement in this process. We provide evidence that both mTOR complexes are crucial for the proper dendritic arbor morphology of hippocampal neurons. These two complexes are required for dendritic development both under basal conditions and upon the induction of mTOR-dependent dendritic growth. We also identified Akt as a downstream effector of mTORC2 needed for proper dendritic arbor morphology, the action of which required mTORC1 and p70S6K1.     

Cloning and nucleotide sequence of cDNA for the plastid glycerol-3-phosphate acyltransferase from squash

The partial amino acid sequence and amino acid composition of acyl-(acyl-carrier-protein):glycerol-3-phosphate acyltransferase purified from squash cotyledons were determined. cDNAs encoding this enzyme were isolated from lambda gt 11 cDNA libraries made from poly(A)+ RNA of squash cotyledons by immunological selection and cross-hybridization. One of the resultant clones contained a cDNA insert of 1426 base pairs and an open reading frame of 1188 base pairs. The amino acid sequence deduced from the nucleotide sequence matched the partial amino acid sequence determined for the enzyme. The results suggest that a precursor protein of 396 amino acid residues is processed to the mature enzyme of 368 amino acid residues, losing a leader peptide of 28 amino acid residues. Relative molecular masses of the precursor and mature proteins were calculated to be 43,838 and 40,929 Da, respectively.     

Uptake of α-Ketoglutarate by Citrate Transporter CitP Drives Transamination in Lactococcus lactis

Transamination is the first step in the conversion of amino acids into aroma compounds by lactic acid bacteria (LAB) used in food fermentations. The process is limited by the availability of α-ketoglutarate, which is the best α-keto donor for transaminases in LAB. Here, uptake of α-ketoglutarate by the citrate transporter CitP is reported. Cells of Lactococcus lactis IL1403 expressing CitP showed significant levels of transamination activity in the presence of α-ketoglutarate and one of the amino acids Ile, Leu, Val, Phe, or Met, while the same cells lacking CitP showed transamination activity only after permeabilization of the cell membrane. Moreover, the transamination activity of the cells followed the levels of CitP in a controlled expression system. The involvement of CitP in the uptake of the α-keto donor was further demonstrated by the increased consumption rate in the presence of l-lactate, which drives CitP in the fast exchange mode of transport. Transamination is the only active pathway for the conversion of α-ketoglutarate in IL1403; a stoichiometric conversion to glutamate and the corresponding α-keto acid from the amino acids was observed. The transamination activity by both the cells and the cytoplasmic fraction showed a remarkably flat pH profile over the range from pH 5 to pH 8, especially with the branched-chain amino acids. Further metabolism of the produced α-keto acids into α-hydroxy acids and other flavor compounds required the coupling of transamination to glycolysis. The results suggest a much broader role of the citrate transporter CitP in LAB than citrate uptake in the citrate fermentation pathway alone.