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Resistance Markers (resistance + marker)
Kinds of Resistance Markers Selected AbstractsWorkshop 5: NAAG and NAALADase: Functional Properties in the Central and Peripheral Nervous SystemJOURNAL OF NEUROCHEMISTRY, Issue 2002D. Bacich Glutamate carboxypeptidase II (GCPII, also known as N-acetylated-alpha-linked acidic dipeptidase or NAALADase) knockout (KO) mice were generated by inserting a GCPII targeting cassette containing a PGK-Neo resistance marker and stop codons in exons 1 and 2, and removal of exons 1 and 2 intron/exon boundary sequence. Embryonic stem cells were injected into C57BL6 blastocysts, and chimeric offspring born. Germline transmission was confirmed by mating the chimeras to generate heterozygous KO mice. Crossing heterozygous mice generated F2 generation mice homozygous for the null mutant, as confirmed by loss of GCPII protein. NAAG hydrolyzing activity was minimal (0.07 pmol/mg/min) in KO tissue, with normal levels (4.82 pmol/mg/min) in wild types and intermediate levels (1.73 pmol/mg/min) in heterozygotes. Preliminary neuropathy experiments showed KO mice are less affected by nerve-crush and recover faster from the damage-induced neuropathy, as indicated by EMG recording and nerve morphology. Similarly, GCPII KO mice subjected to high dose vitamin B6 displayed less severe neuropathy than wild types, as indicated by reduced sensory nerve conduction velocity and morphological deficits. Also, in a transient middle cerebral artery occlusion model, GCPII KO mice were significantly more resistant to the effects of cerebral ischemia than their wildtype littermates. Findings support GCPII involvement in stroke and in mediating chronic neuropathic conditions and suggest GCPII inhibitors may be useful in treatment of brain ischemia as well as peripheral neuropathies. [source] The rpf gene of Micrococcus luteus encodes an essential secreted growth factorMOLECULAR MICROBIOLOGY, Issue 3 2002Galina V. Mukamolova Summary Micrococcus luteus secretes a small protein called Rpf, which has autocrine and paracrine signalling functions and is required for the resuscitation of dormant cells. Originally isolated from the supernatant of actively growing cultures, Rpf was also detected on the surface of actively growing bacteria. Most molecules may be sequestered non-productively at the cell surface, as a truncated form of the protein, encompassing only the ,Rpf domain' is fully active. The C-terminal LysM module, which probably mediates binding to the cell envelope, is not required for biological activity. Rpf was essential for growth of M. luteus. Washed cells, inoculated at low density into a minimal medium, could not grow in its absence. Moreover, the incorporation of anti-Rpf antibodies into the culture medium at the time of inoculation also prevented bacterial growth. We were unable to inactivate rpf using a disrupted form of the gene, in which most of the coding sequence was replaced with a selectable thiostrepton resistance marker. Gene disruption was possible in the presence of a second, functional, plasmid-located copy of rpf, but not in the presence of a rpf derivative whose protein product lacked the secretory signal sequence. As far as we are aware, Rpf is the first example of a truly secreted protein that is essential for bacterial growth. If the Rpf-like proteins elaborated by Mycobacterium tuberculosis and other mycobacteria prove similarly essential, interference with their proper functioning may offer novel opportunities for protecting against, and treating, tuberculosis and other mycobacterial disease. [source] Targeting tumor metabolism with 2-deoxyglucose in patients with castrate-resistant prostate cancer and advanced malignanciesTHE PROSTATE, Issue 13 2010Mark Stein Abstract BACKGROUND A profound difference between cancer and normal tissues is the preferential utilization of glycolysis by cancer cells. To translate this paradigm in the clinic, we completed a phase I study of 2-deoxyglucose (2DG), and assessed 2DG uptake with fluorodeoxyglucose (FDG) positron emission tomography (PET) and the autophagy substrate p62 as a marker of 2DG resistance. METHODS Patients received 2DG orally on days 1,14 of a 21-day cycle in cohorts of three in a dose-escalating manner. Correlative assessments included PET scans at baseline and day 2 and p62 protein in peripheral blood mononuclear cells as a potential marker of 2DG resistance. RESULTS The dose of 45,mg/kg was defined as the recommended phase II dose, secondary to dose-limiting toxicity of grade 3 asymptomatic QTc prolongation at a dose of 60,mg/kg. PK evaluation of 2DG revealed linear pharmacokinetics with Cmax 45,µg/ml (277,µM), 73.7,µg/ml (449,µM), and 122,µg/ml (744,µM) in dose levels 30, 45, and 60,mg/kg, respectively. Five of eight patients assessed with FDG-PET scanning demonstrated decreased FDG uptake by day 2 of therapy, suggesting competition of 2DG with FDG. Five of six patients assessed for p62 had a decrease in p62 at 24,hr. CONCLUSIONS These data support the safety of 2DG, defined 2DG PK, demonstrated the effect of 2DG on FDG-PET imaging, and demonstrated the feasibility of assessment of p62 as an autophagic resistance marker. These data support future studies of 2DG alone or in combination with approaches to abrogate autophagy. Prostate 70: 1388,1394, 2010. © 2010 Wiley-Liss, Inc. [source] Association of BLV infection profiles with alleles of the BoLA-DRB3.2 geneANIMAL GENETICS, Issue 4 2008M. A. Juliarena Summary Bovine leukaemia virus (BLV) causes lymphosarcoma and persistent lymphocytosis (PL). Some MHC class II gene polymorphisms have been associated with resistance and susceptibility to the development of lymphosarcoma and PL, as well as with a reduced number of circulating BLV-infected lymphocytes. Previously, 230 BLV-infected Holstein cattle were classified into two infection profiles characterized by low and high proviral loads (LPL and HPL respectively). Here, the influence of the polymorphism at the BoLA-DRB3.2* gene of these animals was examined. After genotyping, the association between the BoLA-DRB3.2* alleles and the BLV infection profile was determined as the odds ratio (OR). Two subtypes of allele *11 were identified (ISAG*0901 and *0902). Allele ISAG*0902 showed a stronger association with the LPL profile (OR = 8.24; P < 0.0001) than allele *11 itself (OR = 5.82; P < 0.0001). Allele ISAG*1701 (*12) also showed significant association with the LPL profile (OR = 3.46; P < 0.0055). Only one allele, ISAG*1501 or 03 (*16), showed significant association with HPL (OR = 0.36; P < 0.0005). The DRB3.2* alleles were assigned to three categories: resistant (R), susceptible (S) and neutral (N). Based on their DRB3 genotypes, cattle were classified as homozygous or heterozygous. The RR and RN genotypes were associated with the LPL profile, while the SS and NS genotypes were associated with the HPL profile. The RS genotype could not be associated with any particular profile. Our results show that allele ISAG*0902 appears to be the best BLV resistance marker in Holstein cattle. [source] Ascorbic acid oral treatment modifies lipolytic response and behavioural activity but not glucocorticoid metabolism in cafeteria diet-fed ratsACTA PHYSIOLOGICA, Issue 4 2009D. F. Garcia-Diaz Abstract Aim:, To analyse the effects of vitamin C (VC), a potent dietary antioxidant, oral supplementation on body weight gain, behavioural activity, lipolytic response and glucocorticoid metabolism in the early stages of diet-induced overweight in rats. Methods:, Food intake, locomotive activity and faecal corticosterone were assessed during the 14 day trial period. After 2 weeks, the animals were sacrificed and the body composition, biochemical markers and lipolytic response from isolated adipocytes from retroperitoneal white adipose tissue were examined. Results:, The intake of a high-fat diet by rats induced a significant increase in body weight, adiposity and insulin resistance markers as well as a decrease in faecal corticosterone levels compared with standard diet-fed rats. Interestingly, the animals fed on the cafeteria diet showed a significant increase in the isoproterenol-induced lipolytic response in isolated adipocytes. Furthermore, this cafeteria-fed group showed a reduced locomotive behaviour than the control rats. On the other hand, oral VC supplementation in animals receiving the high-fat diet restored the cafeteria diet effect in some of the analysed variables such as final body weight and plasma insulin to control group levels. Remarkably, increases in locomotive behaviour and a significant decrease in the lipolytic response induced by isoproterenol on isolated adipocytes from animals treated with VC were observed. Conclusion:, This work demonstrates that an oral ascorbic acid supplementation has direct effects on behavioural activity and on adipocyte lipolysis in early obesity stages in rats, which could indicate a protective short-term role of this vitamin against adiposity induced by chronic high-fat diet consumption. [source] Human safety and genetically modified plants: a review of antibiotic resistance markers and future transformation selection technologiesJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2005D.A. Goldstein [source] Weak and non-independent association between plasma TAFI antigen levels and the insulin resistance syndromeJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 4 2003H. Aubert Summary., Increased plasma thrombin-activatable fibrinolysis inhibitor (TAFI) levels were recently shown to be a part of the insulin resistance syndrome. We investigated the relationship between plasma TAFI antigen levels and insulin resistance markers and compared these results with those obtained for PAI-1 and fibrinogen which are known to be closely related to insulin resistance syndrome and fat mass, respectively. Eighty-nine obese females had 1.3-, 1.2-, and 3-fold higher circulating TAFI, fibrinogen and PAI-1, respectively, compared with 64 lean females. Univariate analysis showed that the significance level for association between TAFI or fibrinogen concentrations and insulin resistance markers was lower than the significance level for association between PAI-1 and insulin resistance markers. Nevertheless, TAFI, fibrinogen, and PAI-1 plasma levels were significantly associated to each other. In linear stepwise ascendant analysis, insulin resistance markers accounted for 50% of the interindividual variability of plasma PAI-1 and only for 10% of plasma TAFI and 13% of fibrinogen variability. The contribution of insulin resistance markers to plasma TAFI antigen levels variability disappeared when PAI-1 or fibrinogen was entered in the statistical model. TAFI mRNA was detected in the liver but not in adipose tissue and endothelial cells. No TAFI mRNA was detected in normal or atherosclerotic vessels either. These results suggest that elevated TAFI antigen levels found in obese subjects are not independently associated with the metabolic markers of the insulin resistance syndrome. Increased plasma TAFI antigen levels in obesity might reflect a specific pathway of regulation at the liver level. [source] An Arabidopsis thaliana ABC transporter that confers kanamycin resistance in transgenic plants does not endow resistance to Escherichia coliMICROBIAL BIOTECHNOLOGY, Issue 2 2008Kellie Burris Summary Concerns have been raised about potential horizontal gene transfer (HGT) of antibiotic resistance markers (ARMs) from transgenic plants to bacteria of medical and environmental importance. All ARMs used in transgenic plants have been bacterial in origin, but it has been recently shown that an Arabidopsis thaliana ABC transporter, Atwbc19, confers kanamycin resistance when overexpressed in transgenic plants. Atwbc19 was evaluated for its ability to transfer kanamycin resistance to Escherichia coli, a kanamycin-sensitive model bacterium, under simulated HGT, staged by subcloning Atwbc19 under the control of a bacterial promoter, genetically transforming to kanamycin-sensitive bacteria, and assessing if resistance was conferred as compared with bacteria harbouring nptII, the standard kanamycin resistance gene used to produce transgenic plants. NptII provided much greater resistance than Atwbc19 and was significantly different from the no-plasmid control at low concentrations. Atwbc19 was not significantly different from the no-plasmid control at higher concentrations. Even though HGT risks are considered low with nptII, Atwbc19 should have even lower risks, as its encoded protein is possibly mistargeted in bacteria. [source] Contrasting genetic structures of two parasitic nematodes, determined on the basis of neutral microsatellite markers and selected anthelmintic resistance markersMOLECULAR ECOLOGY, Issue 24 2009A. SILVESTRE Abstract For the first time, the neutral genetic relatedness of natural populations of Trichostrongylid nematodes was investigated in relation to polymorphism of the ,-tubulin gene, which is selected for anthelminthic treatments. The aim of the study was to assess the contribution of several evolutionary processes: migration and genetic drift by neutral genetic markers and selection by anthelminthic treatments on the presence of resistance alleles at ,-tubulin. We studied two nematode species (Teladorsagia circumcincta and Haemonchus contortus) common in temperate climatic zones; these species are characterized by contrasting life history traits. We studied 10 isolated populations of goat nematode parasites: no infected adult goat had been exchanged after the herds were established. Beta-tubulin polymorphism was similar in these two species. One and two ,-tubulin alleles from T. circumcincta and H. contortus respectively were shared by several populations. Most of the ,-tubulin alleles were ,private' alleles. No recombination between alleles was detected in BZ-resistant alleles from T. circumcincta and H. contortus. The T. circumcincta populations have not diverged much since their isolation (FST <0.08), whereas H. contortus displayed marked local genetic differentiation (FST ranging from 0.08 to 0.18). These findings suggest that there are severe bottlenecks in the H. contortus populations, possibly because of their reduced abundance during unfavourable periods and their high reproductive rate, which allows the species to persist even after severe population reduction. Overall, the data reported contradict the hypothesis of the origin of ,-tubulin resistance alleles in these populations from a single mutational event, but two other hypotheses (recurrent mutation generating new alleles in isolated populations and the introduction of existing alleles) emerge as equally likely. [source] Zeocin resistance as a dominant selective marker for transformation and targeted gene deletions in Candida glabrataMYCOSES, Issue 6 2006Alex J. Alderton Summary Many of the genetic tools used to generate gene knockouts in Candida glabrata exploit auxotrophic markers but this is not suitable for use with clinical strains. Antibiotic resistance markers, however, allow one to target genes to be deleted without any prior genetic manipulation of clinical isolates. Such antibiotic selection markers have been widely reported for the manipulation of Saccharomyces cerevisiae. However, very few antibiotic resistance markers have been shown to be useful in C. glabrata. Here, we report the use of Zeocin resistance (ZeoR), encoded by the ble gene from Streptoalloteichus hindustanus, as a new positive selection marker for the genetic manipulation of C. glabrata including clinical strains that we show are significantly more sensitive to Zeocin than to G418. The potential of the ZeoR marker for targeted gene disruption in C. glabrata was confirmed by constructing deletions of the ADE2 in both a laboratory and a clinical strain of C. glabrata, using both short (90 bp) and long (400 bp) homology cassettes. [source] Current status of insecticide resistance in Q biotype Bemisia tabaci populations from CretePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2009Emmanouil Roditakis Abstract BACKGROUND: A major problem of crop protection in Crete, Greece, is the control of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) with chemical insecticides owing to the rapid development of resistance. The aim of this study was to investigate the establishment of resistance and the underlying mechanisms to major insecticide classes with classical bioassays and known biochemical resistance markers. RESULTS: During a 2005,2007 survey, 53 Q biotype populations were collected. Application history records showed extensive use of neonicotinoids, organophosphates, carbamates and pyrethroids. High resistance levels were identified in the majority of populations (>80%) for imidacloprid (RF: 38,1958×) and ,-cypermethrin (RF: 30,600×). Low resistance levels (RF < 12) were observed for pirimiphos-methyl. A strong correlation between resistance to imidacloprid and the number of applications with neonicotinoids was observed. Significant correlations were observed between COE and P450-dependent monoxygenase activity with resistance to ,-cypermethrin and imidacloprid respectively. A propoxur-based AChE diagnostic test indicated that iAChE was widespread in most populations. Resistance levels for ,-cypermethrin were increased when compared with a previous survey (2002,2003). Differentiation of LC50 values between localities was observed for imidacloprid only. CONCLUSION:Bemisia tabaci resistance evolved differently in each of the three insecticides studied. Imidacloprid resistance seems less established and less persistent than ,-cypermethrin resistance. The low resistance levels for pirimiphos-methyl suggest absence of cross-resistance with other organophosphates or carbamates used. Copyright © 2008 Society of Chemical Industry [source] pFARs, Plasmids free of antibiotic resistance markers, display high-level transgene expression in muscle, skin and tumour cellsTHE JOURNAL OF GENE MEDICINE, Issue 4 2010Corinne Marie Abstract Background Nonviral gene therapy requires a high yield and a low cost production of eukaryotic expression vectors that meet defined criteria such as biosafety and quality of pharmaceutical grade. To fulfil these objectives, we designed a novel antibiotic-free selection system. Methods The proposed strategy relies on the suppression of a chromosomal amber mutation by a plasmid-borne function. We first introduced a nonsense mutation into the essential Escherichia coli thyA gene, resulting in thymidine auxotrophy. The bacterial strain was optimized for the production of small and novel plasmids free of antibiotic resistance markers (pFARs) and encoding an amber suppressor t-RNA. Finally, the potentiality of pFARs as eukaryotic expression vectors was assessed by monitoring luciferase activities after electrotransfer of LUC-encoding plasmids into various tissues. Results The introduction of pFARs into the optimized bacterial strain restored normal growth to the auxotrophic mutant and allowed an efficient production of monomeric supercoiled plasmids. The electrotransfer of LUC-encoding pFAR into muscle led to high luciferase activities, demonstrating an efficient gene delivery. In transplanted tumours, transgene expression levels were superior after electrotransfer of the pFAR derivative compared to a plasmid carrying a kanamycin resistance gene. Finally, in skin, whereas luciferase activities decreased within 3 weeks after intradermal electrotransfer of a conventional expression vector, sustained luciferase expression was observed with the pFAR plasmid. Conclusions Thus, we have designed a novel strategy for the efficient production of biosafe plasmids and demonstrated their potentiality for nonviral gene delivery and high-level transgene expression in several tissues. Copyright © 2010 John Wiley & Sons, Ltd. [source] | |||||||||||||