ABSTRACT
Leptin targets specific receptors (OB-R) expressed in the hypothalamus to regulate energy balance. Leptin decreases food intake in normal weight individuals, but this effect is blunted in obese subjects who are characterized by a state of leptin resistance. The prevention of leptin resistance is one of the major goals of obesity research. Recently, we identified endospanin 1 as a negative regulator of OB-R, which by interacting with OB-R retains the receptor inside the cell. We show here that in obese mice endospanin 1 is upregulated in the hypothalamic arcuate nucleus (ARC), the major brain structure involved in body weight regulation, suggesting that endospanin 1 is implicated in obesity development and/or the installation of leptin resistance. In contrast, silencing of endospanin 1 with lentiviral vectors in the ARC of obese mice fully restores leptin responsiveness when combined with a switch to ad libitum fed chow diet. The recovery of central leptin sensitivity is accompanied by sustained body weight loss and amelioration of blood lipid parameters and steatosis. Collectively, our results define endospanin 1 as a novel therapeutic target against obesity.
Subject(s)
Arcuate Nucleus of Hypothalamus/metabolism , Carrier Proteins/metabolism , Leptin/metabolism , Obesity/metabolism , Animals , Carrier Proteins/genetics , Diet, High-Fat , Gene Expression Regulation , Intracellular Signaling Peptides and Proteins , Lipids/blood , Male , Mice , Mice, Inbred C57BL , Mice, Obese , STAT3 Transcription Factor/metabolism , Weight LossABSTRACT
Elaboration of minimally processed or fresh-cut vegetables requires a quick and reliable method for detection of bacterial contamination over the recommended limits. PCR-based methods fulfil these requirements, but amplification from DNA preparations of the food product is often hampered due to inhibiting substances. The purpose of this study was to develop a fast quantitative PCR (qPCR)-based method for aerobic bacterial enumeration in fresh-cut lettuce, using as reference the centrifugation water (CW) that comes up during processing instead of the food matrix itself. Comparisons between bacterial numbers on lettuce leaves before processing and bacterial numbers in the CW both for naturally occurring bacterial populations and for artificially inoculated lettuce were performed. On an average, 35% of the natural bacterial population and 64% of inoculated bacteria were recovered in the CW. Bacterial number in CW was proportional to initial lettuce contamination suggesting that measures on CW allow a narrow estimation of lettuce contamination. In qPCR, a 23S rDNA region was amplified from bacterial DNA present in the CW, followed by melting peak analyses and quantification. Enumeration of cell number by qPCR did not differ significantly from plate assay and might therefore replace it. The proposed protocol, which includes sample taking, DNA extraction and qPCR from the CW can be performed within less than 5 h. The resulting quantification might be used as a proxy of initial lettuce contamination, allowing direct intervention measures before fresh-cut commodity is shipped from the factory.
Subject(s)
Bacteria, Aerobic/isolation & purification , DNA, Bacterial/isolation & purification , Food Microbiology , Lactuca/microbiology , Bacteria, Aerobic/genetics , DNA, Bacterial/genetics , Polymerase Chain ReactionABSTRACT
A multicenter study including 10 outpatient private laboratories (hospital laboratories excluded) was carried out in France. 1,611 urines samples from patients with UTI were collected during the forth trimester of 1987. The most frequently recovered pathogens were: E. coli (71%), Proteus mirabilis (9%), Staphylococcus coagulase (6%), Klebsiella (6%), Enterobacter (2%). Other sorts (Streptococcus D, Proteus sp, Pseudomonas aeruginosa, Enterobacter sp) were infrequent (less than 1%). The sensitivity of the aerobic Gram-negative bacteria to ampicillin, clavulanic acid-amoxicillin, cephalothin, gentamicin, pipemidic acid, norfloxacin and co-trimoxazole was tested.
