Enumeration of Campylobacter in New Zealand recreational and drinking waters

AIMS: To use a published polymerase chain reaction (PCR) method for the detection and identification of thermotolerant Campylobacter species (Camp. jejuni, Camp. coli and Camp. lari) in tandem with a Most Probable Number (MPN) technique to enumerate these species in water samples. METHODS AND RESULTS: An initial study of 42 river water samples compared the use of conventional culture and PCR methods for the detection of Campylobacter in MPN enrichment tubes. It was found that all samples positive by culture were also positive by PCR. Thirty-seven percent more MPN tubes were positive by PCR compared with culture. The MPN/PCR technique was subsequently applied to 96 additional samples collected from rivers, drinking, roof and shallow ground water. Campylobacter was especially prevalent in river water (60% positive) and shallow ground water (75% positive) samples. Drinking water (29.2% positive) and roof water (37.5% positive) also contained Campylobacter, but the numbers detected were very low (maximum 0.3 and 0.56 MPN 100 ml-1, respectively). CONCLUSION: River waters contained Campylobacter at higher levels than any other water type and in a high percentage of the samples. Although Campylobacter was present in treated drinking water, the levels detected were low. SIGNIFICANCE AND IMPACT OF THE STUDY: These results suggest that water may act as a significant transmission route for human campylobacteriosis.     

Effects of Insulin Therapy on Myocardial Lipid Content and Cardiac Geometry in Patients with Type-2 Diabetes Mellitus

Aims/Hypothesis

Recent evidence suggests a link between myocardial steatosis and diabetic cardiomyopathy. Insulin, as a lipogenic and growth-promoting hormone, might stimulate intramyocardial lipid (MYCL) deposition and hypertrophy. Therefore, the aim of the present study was to investigate the short-term effects of insulin therapy (IT) on myocardial lipid content and morphology in patients with T2DM.

Methods

Eighteen patients with T2DM were recruited (age 56±2 years; HbA1c: 10.5±0.4%). In 10 patients with insufficient glucose control under oral medication IT was initiated due to secondary failure of oral glucose lowering therapy (IT-group), while 8 individuals did not require additional insulin substitution (OT-group). In order to assess MYCL and intrahepatic lipid (IHLC) content as well as cardiac geometry and function magnetic resonance spectroscopy (MRS) and imaging (MRI) examinations were performed at baseline (IT and OT) and 10 days after initiation of IT. Follow up measurements took place 181±49 days after IT.

Results

Interestingly, basal MYCLs were 50% lower in IT- compared to OT-group (0.41±0.12 vs. 0.80±0.11% of water signal; p = 0.034). After 10 days of IT, an acute 80%-rise in MYCL (p = 0.008) was observed, while IHLC did not change. Likewise, myocardial mass (+13%; p = 0.004), wall thickness in end-diastole (+13%; p = 0.030) and concentricity, an index of cardiac remodeling, increased (+28%; p = 0.026). In the long-term MYCL returned to baseline, while IHCL significantly decreased (−31%; p = 0.000). No acute changes in systolic left ventricular function were observed.

Conclusions/Interpretation

The initiation of IT in patients with T2DM was followed by an acute rise in MYCL concentration and myocardial mass.     

Cell-specific inhibition of inducible nitric oxide synthase activation by leflunomide

The influence of a novel immunomodulating drug, leflunomide, on iNOS-dependent nitric oxide (NO) production in rodent macrophages and fibroblasts was investigated. Leflunomide's active metabolite A77 1726 caused a dose-dependent decrease of NO production in IFN-gamma-treated L929 fibroblasts. The observed effect was cell-specific, as well as stimulus-specific, since A77 1726 did not affect NO production in IFN-gamma-stimulated murine peritoneal macrophages or db-cAMP-treated L929 cells. A77 1726 reduced expression of IFN-gamma-induced iNOS and IRF-1 mRNA in L929 cells, while iNOS enzymatic activity remained unchanged. Specific inhibitor of MAP kinase kinase (MEK), PD98059, but not unselective protein kinase inhibitor genistein, completely mimicked cell-type-specific and stimulus-specific NO-inhibitory action of leflunomide. Therefore, the recently described inhibition of MEK/MAP pathway by leflunomide could present a possible mechanism for its suppression of iNOS activation in L929 fibroblasts. Finally, a similar inhibitory effect of A77 1726 on both NO production and iNOS mRNA expression was observed also in IFN-gamma + LPS-activated murine and rat primary fibroblasts.     

The Role of Alpha-Synuclein in Melanin Synthesis in Melanoma and Dopaminergic Neuronal Cells

The relatively high co-occurrence of Parkinson’s disease (PD) and melanoma has been established by a large number of epidemiological studies. However, a clear biological explanation for this finding is still lacking. Ultra-violet radiation (UVR)-induced skin melanin synthesis is a defense mechanism against UVR-induced damage relevant to the initiation of melanoma, whereas, increased neuromelanin (NM), the melanin synthesized in dopaminergic neurons, may enhance the susceptibility to oxidative stress-induced neuronal injury relevant to PD. SNCA is a PD-causing gene coding for alpha-Synuclein (α-Syn) that expresses not only in brain, but also in skin as well as in tumors, such as melanoma. The findings that α-Syn can interact with tyrosinase (TYR) and inhibit tyrosine hydroxylase (TH), both of which are enzymes involved in the biosynthesis of melanin and dopamine (DA), led us to propose that α-Syn may participate in the regulation of melanin synthesis. In this study, by applying ultraviolet B (UVB) light, a physiologically relevant stimulus of melanogenesis, we detected melanin synthesis in A375 and SK-MEL-28 melanoma cells and in SH-SY5Y and PC12 dopaminergic neuronal cells and determined effects of α-Syn on melanin synthesis. Our results showed that UVB light exposure increased melanin synthesis in all 4 cell lines. However, we found that α-Syn expression reduced UVB light-induced increase of melanin synthesis and that melanin content was lower when melanoma cells were expressed with α-Syn, indicating that α-Syn may have inhibitory effects on melanin synthesis in melanoma cells. Different from melanoma cells, the melanin content was higher in α-Syn-over-expressed dopaminergic neuronal SH-SY5Y and PC12 cells, cellular models of PD, than that in non-α-Syn-expressed control cells. We concluded that α-Syn could be one of the points responsible for the positive association between PD and melanoma via its differential roles in melanin synthesis in melanoma cells and in dopaminergic neuronal cells.     

Pericardial- Rather than Intramyocardial Fat Is Independently Associated with Left Ventricular Systolic Heart Function in Metabolically Healthy Humans

Background

Obesity is a major risk factor to develop heart failure, in part due to possible lipotoxic effects of increased intramyocardial (MYCL) and/or local or paracrine effects of pericardial (PERI) lipid accumulation. Recent evidence suggests that MYCL is highly dynamic and might rather be a surrogate marker for disturbed energy metabolism than the underlying cause of cardiac dysfunction. On the other hand, PERI might contribute directly by mechanic and paracrine effects. Therefore, we hypothesized that PERI rather than MYCL is associated with myocardial function.

Methods

To avoid potential confounding of metabolic disease 31 metabolically healthy subjects (age: 29±10yrs; BMI: 23±3kg/m²) were investigated using ¹H-magnetic resonance spectroscopy and imaging. MYCL and PERI, as well as systolic and diastolic left ventricular heart function were assessed. Additionally, anthropometric data and parameters of glucose and lipid metabolism were analyzed. Correlation analysis was performed using Pearson’s correlation coefficient. Linear regression model was used to show individual effects of PERI and MYCL on myocardial functional parameters.

Results

Correlation analysis with parameters of systolic heart function revealed significant associations for PERI (Stroke Volume (SV): R = -0.513 p = 0.001; CardiacIndex (CI): R = -0.442 p = 0.014), but not for MYCL (SV: R = -0.233; p = 0.207; CI: R = -0.130; p = 0.484). No significant correlations were found for E/A ratio as a parameter of diastolic heart function. In multiple regression analysis CI was negatively predicted by PERI, whereas no impact of MYCL was observed in direct comparison.

Conclusions

Cardiac fat depots impact left ventricular heart function in a metabolically healthy population. Direct comparison of different lipid stores revealed that PERI is a more important predictor than MYCL for altered myocardial function.     

Carbon catabolite repression of sucrose utilization in Staphylococcus xylosus: catabolite control protein CcpA ensures glucose preference and autoregulatory limitation of sucrose utilization

Sucrose utilization in Staphylococcus xylosus is dependent on two genes, scrA and scrB; encoding a PTS permease and a sucrose phosphate hydrolase, respectively. The genes are encoded on separate loci and are transcribed from two promoters, P(scrA) and P(scrB), both of which are controlled by the repressor ScrR by binding to the operator sequences O(A) and O(B). In the scrA promoter region, a catabolite-responsive element (cre), operator for the global catabolite control protein CcpA, is also present, but its contribution to scrA regulation has not been determined. Using an integrative promoter probe plasmid, the activities of the promoters P(scrA) and P(scrB) were determined under different growth conditions. Both promoters are induced by sucrose and induction is prevented when glucose is also present. Without a functional CcpA, glucose-mediated prevention of induction is lost, clearly demonstrating that CcpA ensures hierarchical sugar utilization with glucose as preferred substrate. Measurements of promoter activities in the absence of a functional ScrR repressor indicated that CcpA also acts upon the operators O(A) and O(B), albeit not as efficiently as on the genuine cre in P(srcA). Besides determining the choice of the carbon source, CcpA has a second effect on sucrose gene expression. When sucrose is the sole carbon source, sucrose catabolism activates carbon catabolite repression and CcpA prevents full induction of the sucrose utilization genes by partially repressing the scrA promoter. Thus, CcpA-dependent regulation serves as a built-in autoregulatory device to restrict sucrose uptake.     

AID is required for c-myc/IgH chromosome translocations in vivo

Chromosome translocations between c-myc and immunoglobulin (Ig) are associated with Burkitt's lymphoma in humans and with pristane- and IL6-induced plasmacytomas in mice. These translocations frequently involve Ig switch regions, suggesting that they might be the result of aberrant Ig class switch recombination (CSR). However, a direct link between CSR and chromosome translocations has not been established. We have examined c-myc/IgH translocations in IL6 transgenic mice that are mutant for activation induced cytidine deaminase (AID), the enzyme that initiates CSR. Here we report that AID is essential for the c-myc/IgH chromosome translocations induced by IL6.