Occurrence of 16s rRNA methylase ArmA producing Enterobacteriaceae in a general hospital in Warsaw, Poland

Resistance to gentamicin, amikacin and kanamycin was screened in 270 clinical isolates of Enterobacteriaceae originated from April 19 to May 19, 2010 in a regular hospital in Warsaw, Poland. Most of the isolated bacteria were considered pathogenic. Nineteen isolates (7%) were simultaneously resistant to two or three of the tested aminoglycosides. MICs of the three aminoglycosides ranged form 128 to 1024 mcg/ml for six isolates. These isolates were suspected to produce 16S rRNA methylase. Genes encoding for three methylases reported in Europe: ArmA, RmtB and RmtC were searched by PCR. The armA gene was detected in all of the six isolates. This group encompassed Enterobacter cloacae (n=4), Klebsiella pneumoniae (n=1) and Proteus mirabilis (n=1). Five isolates of this group carried the bla(CAX-M) gene for CTX-M type ESBL. The remaining isolate E. cloacae DM0340 was ESBL negative and lacked bla(CRX-M) that may suggest an altered genetic environment of the armA gene in this isolate. Our results showed that 2.2% of the tested isolates produced 16S rRNA methylase ArmA. This finding may argue for a high incidence of ArmA producing Enterobacteriaceae in Poland when compared to reports from other European countries.     

Anterior regions of monkey parietal cortex process visual 3D shape

The intraparietal cortex is involved in the control of visually guided actions, like reach-to-grasp movements, which require extracting the 3D shape and position of objects from 2D retinal images. Using fMRI in behaving monkeys, we investigated the role of the intraparietal cortex in processing stereoscopic information for recovering the depth structure and the position in depth of objects. We found that while several areas (CIP, LIP, and AIP on the lateral bank; PIP and MIP on the medial bank) are activated by stereoscopic stimuli, AIP and an adjoining portion of LIP are sensitive only to depth structure. Furthermore, only these two regions are sensitive to both the depth structure and the 2D shape of small objects. These results indicate that extracting 3D spatial information from stereo involves several intraparietal areas, among which AIP and anterior LIP are more specifically engaged in extracting the 3D shape of objects.     

Nf1 and Gmcsf interact in myeloid leukemogenesis

The NF1 tumor suppressor gene encodes neurofibromin, a GTPase-activating protein (GAP) for p21ras (Ras). Children with NF1 are predisposed to juvenile myelomonocytic leukemia (JMML). Some heterozygous Nf1 mutant mice develop a similar myeloproliferative disorder (MPD), and adoptive transfer of Nf1-deficient fetal liver cells consistently induces this MPD. Human JMML and murine Nf1-deficient cells are hypersensitive to granulocyte-macrophage colony-stimulating factor (GM-CSF) in methylcellulose cultures. We generated hematopoietic cells deficient in both Nf1 and Gmcsf to test whether GM-CSF is required to drive excessive proliferation of Nf1-/- cells in vivo. Here we show that GM-CSF play a central role in establishing and maintaining the MPD and that recipients engrafted with Nf1-/- Gmcsf-/- hematopoietic cells are hypersensitive to exogenous GM-CSF.     

Identification of Risks in the Life Cycle of Nanotechnology‐Based Products

In order to realize the projected market potential of nanotechnology, the environmental, health, and safety (EHS) uncertainties posed by a nano‐product (i.e., a nanotechnology‐enabled product) need to be characterized through the identification of risks and opportunities in early stages of product development. We present a methodology to identify risks from nano‐products using a scenario analysis approach that allows for expert elicitation on a set of preidentified use and disposal scenarios and what we have labeled “risk triggers” to obtain scores on their likelihood of occurrence and severity. Use and disposal scenarios describe product life‐cycle stages that could result in risk attributed to the nano‐product, whereas risk triggers are particular to nanoparticle properties. These are potential risks, as the risk assessment community is currently debating the specific risks attributed to nanotechnology. Through such a framework, our goal is to identify which products pose greater risks, where these risks occur in the product life cycle, and the impacts of these environmental risks on society. The comparison of risk triggers across nano‐products allows relative risk ranking on axes of exposure‐ and hazard‐related risk triggers. For the specific case of air fresheners, areas of acute risks resulted from bioavailability of nanoparticles in air release and water entrainment exposure scenarios; catalytic activity of nanoparticles in inhalation and air release exposure scenarios; the harmful effects due to the antibacterial property on useful bacteria particularly in susceptible populations; and, finally, risks from the lack of nanoparticle coating stability in air release scenarios.     

Visualization of microarray gene expression data

Microarray gene expression data is used in various biological and medical investigations. Processing of gene expression data requires algorithms in data mining, process automation and knowledge discovery. Available data mining algorithms exploits various visualization techniques. Here, we describe the merits and demerits of various visualization parameters used in gene expression analysis.     

PCR-restriction fragment length polymorphism assay (PCR-RFLP) as an useful tool for detection of mutation in gyrA gene at 86-THR position associated with fluoroquinolone resistance in Campylobacter jejuni

The aim of this study was to investigate the mutations in gyrA gene at Thr-86 position in fluoroquinolone resistant C. jejuni clinical isolates (2003-2005). The change of Thr to Ile at 86 position is associated with high-level resistance to fluoroquinolone in C. jejuni. Thirty five (58%) of 65 C. jejuni strains were found to be resistant to ciprofloxacin using E-test method. PCR-RFLP technique with the RsaI enzyme was used for the identification of mutation in gyrA gene. The primers spanning a part of the fluoroquinolone resistance determining region (QRDR) were designed based on the article of Alonso et al. and the gyrA sequence of C. jejuni (Gen Bank accession number LO4566). One of this primer had mismatch introduced at the second nucleotide from 3' end of the primer what gives an artificial RsaI cleavage site. All of the ciprofloxacin-resistant isolates contained a single)point mutation in the gyrA gene: the replacement of Thr 86 by Ile. The results showed that PCR-RFLP is a rapid and simple method for the detection of the high-level fluoroquinolone resistance in C. jejuni.     

Mutation to Bax beyond the BH3 domain disrupts interactions with pro-survival proteins and promotes apoptosis

Pro-survival members of the Bcl-2 family of proteins restrain the pro-apoptotic activity of Bax, either directly through interactions with Bax or indirectly by sequestration of activator BH3-only proteins, or both. Mutations in Bax that promote apoptosis can provide insight into how Bax is regulated. Here, we describe crystal structures of the pro-survival proteins Mcl-1 and Bcl-x(L) in complex with a 34-mer peptide from Bax that encompasses its BH3 domain. These structures reveal canonical interactions between four signature hydrophobic amino acids from the BaxBH3 domain and the BH3-binding groove of the pro-survival proteins. In both structures, Met-74 from the Bax peptide engages with the BH3-binding groove in a fifth hydrophobic interaction. Various Bax Met-74 mutants disrupt interactions between Bax and all pro-survival proteins, but these Bax mutants retain pro-apoptotic activity. Bax/Bak-deficient mouse embryonic fibroblast cells reconstituted with several Bax Met-74 mutants are more sensitive to the BH3 mimetic compound ABT-737 as compared with cells expressing wild-type Bax. Furthermore, the cells expressing Bax Met-74 mutants are less viable in colony assays even in the absence of an external apoptotic stimulus. These results support a model in which direct restraint of Bax by pro-survival Bcl-2 proteins is a barrier to apoptosis.     

Tigecicline susceptibilities of tetracycline-resistant Campylobacter jejuni clinical strains isolated in Poland

Campylobacteriosis is a significant public health problem in many developed countries. Campylobacter jejuni is one of the leading causes of food-borne gastroenteritis and enteritis in humans. Treatment of campylobacteriosis is required in severe clinical infections, extraintestinal infections and in immunocompromised patients. Erythromycin is the proposed drug of choice for the treatment of Campylobacter infections. However, tetracycline and fluoroquinolones (ciprofloxacin) are also clinically effective agents for treating infections caused by Campylobacter spp. High prevalence of C. jejuni resistant to fluoroquinolone and tetracycline have been recently reported in many countries. In human medicine new agents for the treatment of many serious infections are acutely needed in hospital practice. Tigecycline is a member of a new group of antibiotics--the glycylcyclines with an expanded microbiological spectrum. In our study we will determine the susceptibility of polish, resistant to tetracycline clinical C. jejuni isolates to tigecycline. All 94 tetracycline-resistant C. jejuni strains, with MICs between 8 and 256 mg/l, isolated between 2007 and 2008 were susceptible to tigecycline, with MICs 0.06 mg/1. Tigecycline may has potential therapeutic role in the treatment of serious Campylobacter infections.     

A convenient gram-scale synthesis of uridine diphospho(13C6)glucose

A simple gram-scale synthesis of uridine diphospho(13C6)glucose is presented from D-(13C6)glucose. The critical step uses a 1H-tetrazole-catalyzed coupling of 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl-1-phosphate and UMP-morpholidate. The uridine diphospho(13C6)glucose was used in the structural identification of (1-->3)-beta-D-glucan from Lolium multiflorum.     

Prevalence of pathogenic genes of Campylobacter jejuni isolated from humans in Poland between 2003-2005

Campylobacter jejuni is an important cause of food-borne gastroenteritis and enteritis in humans in many developed countries. Several C. jejuni virulence determinants have been identified. The purpose of our experiments was to determine the prevalence of virulence and toxin genes cadF, flaA, cdtA, cdtB, cdtC, cdtABC, virB11 among 102 C. jejuni isolates isolated in Poland between 2003 and 2005 from humans with diarrhea. The PCR analysis of the strains revealed the presence of the flaA and the cadF genes among all C. jejuni isolates. Detection rates for the cdtA, cdtB, cdtC and cdtABC cluster genes were 98, 96, 92 and 88% respectively. The virB11 gene was found in only 3% of the isolates. The high prevalence of cadF, flaA and cdt genes demonstrated that these genes may play an important role in C. jejuni virulence. Further research is necessary to clarify the importance of the virB11 gene in the pathogenesis of infections with C. jejuni strains in humans.