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Strain Differences (strain + difference)
Selected AbstractsStrain Differences in Behavioral Inhibition in a Go/No-go Task Demonstrated Using 15 Inbred Mouse StrainsALCOHOLISM, Issue 8 2010Noah R. Gubner Background:, High levels of impulsivity have been associated with a number of substance abuse disorders including alcohol abuse. Research has not yet revealed whether these high levels predate the development of alcohol abuse. Methods:, The current study examined impulsivity in 15 inbred strains of mice (A/HeJ, AKR/J, BALB/cJ, C3H/HeJ, C57BL/6J, C57L/J, C58/J, CBA/J, DBA/1J, DBA/2J, NZB/B1NJ, PL/J, SJL/J, SWR/J, and 129P3/J) using a Go/No-go task, which was designed to measure a subject's ability to inhibit a behavior. Numerous aspects of response to ethanol and other drugs of abuse have been examined in these strains. Results:, There were significant strain differences in the number of responses made during the No-go signal (false alarms) and the extent to which strains responded differentially during the Go and No-go signals (d,). The rate of responding prior to the cue did not differ among strains, although there was a statistically significant correlation between false alarms and precue responding that was not related to basal activity level. Interstrain correlations suggested that false alarms and rate of responding were associated with strain differences in ethanol-related traits from the published literature. Conclusions:, The results of this study do support a link between innate level of impulsivity and response to ethanol and are consistent with a genetic basis for some measures of behavioral inhibition. [source] Strain differences in ,1 receptor-mediated behaviours are related to neurosteroid levelsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2002Vân-Ly Phan Abstract The sigma1 (,1) receptor exerts a potent neuromodulatory role in the brain with relevant consequences in memory processes, response to stress, depression and pharmacodependence. Its precise endogenous ligand is not yet identified but the ,1 receptor appears to be one target for the nongenomic rapid effects of neuroactive steroids in the brain. The aim of the present study was to establish whether differences in ,1 receptor-mediated behaviours could be observed among mouse strains, in relation with differences in either ,1 receptor expression or steroid levels. The ,1 -receptor immunohistochemical distribution appeared similar between Swiss and C57BL/6 strains in all the brain structures examined. The levels of in vivo[3H](+)-SKF-10 047 binding to ,1 receptors were lower in Swiss than in C57BL/6. Adrenalectomy/castration significantly increased [3H](+)-SKF-10 047 binding only in Swiss. The behavioural efficacy of the selective ,1 agonists igmesine and PRE-084 , reversion of the scopolamine-induced amnesia in the passive avoidance test; diminution of the immobility duration in the forced swimming test , were significantly higher in C57BL/6 than in Swiss. Steroid levels were measured in the brain in basal conditions and after stress. C57BL/6 mice presented in both conditions, the lowest progesterone levels, this steroid acting as an endogenous ,1 antagonist. Collectively, the results suggested that strain differences in neuroactive steroid and particularly, progesterone, biosynthesis and sensitivity may contribute to the differential behavioural efficacy of ,1 -receptor ligands. Noteworthy, these observations are coherent with strain differences observed in the intensity of cocaine-induced reward properties, known to critically involve the ,1 receptor. [source] Strain differences in the behavioural outcome of neonatal ventral hippocampal lesions are determined by the postnatal environment and not genetic factorsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2001Graham K. Wood Abstract It has been demonstrated that not only do rats neonatally lesioned in the ventral hippocampus (VH) develop behavioural hypersensitivity to amphetamine postpubertally, but also that the expression of the sensitivity is strain specific. For example, excitotoxic VH lesions at postnatal day (PD) 7 lead to significant increases in amphetamine-induced locomotion in postpubertal Fischer rats, but not in Lewis rats. However, as it is likely that the effect of strain differences are due to a combination of genetics and environment, we examined the contributions of the environment of the pups in determining the behavioural outcome following neonatal VH lesions. Fisher and Lewis rat pups were cross-fostered at birth, and then at PD7 lesioned bilaterally in the VH with ibotenic acid. anova analysis of postpubertal amphetamine-induced locomotor data revealed a significant effect of the strain of the dams raising the pups but no effect of the strain of the pup. In addition, a post hoc analysis revealed that lesioned Fisher or Lewis rats raised by Fisher, but not those raised by Lewis, dams demonstrated amphetamine-induced hyperlocomotion relative to nonlesioned controls. Observations of the maternal behaviour of Fischer and Lewis dams revealed significant differences in the frequency of arched-back nursing between the two strains. Interestingly, a correlation of the frequency of arched back nursing vs novelty- or amphetamine-induced locomotion revealed that the lesioned rats were significantly more affected by increases in arched-back nursing compared to the controls. The results suggest that the genetic background of the pups does not significantly affect the behavioural outcome following neonatal VH lesions; however, the results do suggest an important role of early environmental variables on the behavioural outcome of neonatal VH lesions. [source] Hormone response to bidirectional selection on social behaviorEVOLUTION AND DEVELOPMENT, Issue 5 2010Gro V. Amdam SUMMARY Behavior is a quantitative trait determined by multiple genes. Some of these genes may have effects from early development and onward by influencing hormonal systems that are active during different life-stages leading to complex associations, or suites, of traits. Honey bees (Apis mellifera) have been used extensively in experiments on the genetic and hormonal control of complex social behavior, but the relationships between their early developmental processes and adult behavioral variation are not well understood. Bidirectional selective breeding on social food-storage behavior produced two honey bee strains, each with several sublines, that differ in an associated suite of anatomical, physiological, and behavioral traits found in unselected wild type bees. Using these genotypes, we document strain-specific changes during larval, pupal, and early adult life-stages for the central insect hormones juvenile hormone (JH) and ecdysteroids. Strain differences correlate with variation in female reproductive anatomy (ovary size), which can be influenced by JH during development, and with secretion rates of ecdysteroid from the ovaries of adults. Ovary size was previously assigned to the suite of traits of honey bee food-storage behavior. Our findings support that bidirectional selection on honey bee social behavior acted on pleiotropic gene networks. These networks may bias a bee's adult phenotype by endocrine effects on early developmental processes that regulate variation in reproductive traits. [source] Differential effects of lorazepam on sleep and activity in C57BL/6J and BALB/cJ strain miceJOURNAL OF SLEEP RESEARCH, Issue 3 2009XIANGDONG TANG Summary Compared to C57BL/6 mice, BALB/c mice exhibit greater ,anxiousness' on behavioural tests of anxiety, and can show significantly longer sleep disruptions after exposure to anxiogenic situations. Relative to C57BL/6 mice, BALB/c mice also have reduced benzodiazepine (BZ) receptor densities in the brain and fivefold less BZ receptor density in the amygdala, a region important in anxiety and in the control of arousal. Lorazepam is a BZ receptor full agonist and has been used to treat both anxiety and insomnia. Differences between C57BL/6 and BALB/c mice raise the question of whether BZ agonists would impact sleep and activity differentially in the two strains. We examined the effects of two doses of lorazepam (0.5 and 1.5 mg kg,1) or saline alone (0.2 mL) on sleep and activity in C57BL/6 (n = 8) and BALB/c (n = 7) mice. Compared to saline, both doses of lorazepam significantly increased non-rapid eye movement (NREM) and reduced activity in both strains. In C57BL/6 mice, rapid eye movement (REM) was increased at both doses. In BALB/c mice, the 0.5 mg kg,1 dose had no significant influence on REM, whereas REM was reduced significantly after the 1.5 mg kg,1 dose. The results demonstrate significant differences between C57BL/6 and BALB/c mice in the effects of lorazepam on REM, whereas the effects on NREM and activity were similar. Strain differences in the number of BZ receptors in the amygdala, but not other brain regions, suggests possible site specificity in the effects of lorazepam on REM. These differences in BZ-binding sites in the amygdala could be a significant factor in differences in the sleep response between C57 and BALB/c mice. [source] Strain differences in autotomy in mice after peripheral nerve transection or repairMICROSURGERY, Issue 4 2003Roee E. Rubinstein A.B. The purpose of this study was to identify the optimal murine model for the study of peripheral nerve injury and nerve and limb transplantation. The degree of self-mutilation (autotomy) following sciatic and saphenous nerve injury was assessed in four mouse strains, Balb/C, C57BL/6J, C57BL/10J, and C3HEB, commonly used in surgical research. Experimental groups included sciatic and saphenous nerve transection with repair (n = 9) or without repair (n = 9), as well as housing arrangements favoring social interaction vs. isolation. Autotomy was most prevalent in the Balb/c and C3H strains at 56% and 89% overall, respectively, and was much less frequently seen in the C57Bl/10 and C57Bl/6 strains (22% and 11%, respectively). Autotomy was found to correlate most strongly with mouse strain, and with social contact as well. Two strains, C57BL/6J and C57BL/10J, were found to be highly resistant to self-mutilation, and are thus ideal animal models for peripheral-nerve and whole-limb transplant studies. © 2003 Wiley-Liss, Inc. MICROSURGERY 23:363,368 2003 [source] Strain differences in feed efficiency measured as residual feed intake in individually reared rainbow trout, Oncorhynchus mykiss (Walbaum)AQUACULTURE RESEARCH, Issue 7 2005Jeffrey T Silverstein Abstract The efficient use of feed for growth and meat production is important for all animal production industries including aquaculture. Residual feed intake (RFI) is an alternative measure of feed efficiency that has been widely used in livestock production. Residual feed intake was calculated as the difference between intake observed and intake predicted on the basis of a bioenergetics model; a low RFI indicates greater efficiency. Residual feed intake offers some advantages as a selection criterion for improving production efficiency over traditional feed efficiency statistics because it is not a ratio and it typically has a larger coefficient of variation. The RFI of individually reared rainbow trout progeny from six different genetic cross-types was examined for genetic variation. Proximate analysis and nitrogen retention were also evaluated to determine if differences in RFI correlate to differences in body composition and nutrient retention and varied by cross-type. Differences between cross-types indicated a genetic component for RFI, with the most efficient fish of approximately 160 g consuming 0.99 g less and inefficient fish consuming 0.05 g more feed per day than expected. Lower RFI was associated with higher growth rates (r=,0.38, P<0.05) and greater nitrogen retention (r=,0.82 P<0.001). [source] Cytoplasmic proteome reference map for a glutamic acid-producing Corynebacterium glutamicum ATCC 14067PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 23 2007Liyuan Li Abstract We constructed a cytoplasmic proteome reference map for a glutamic acid producing Corynebacterium glutamicum ATCC 14067 by 2-DE and protein identification by MALDI-TOF-MS and PMF using genome database of the type strain ATCC 13032. The map allowed us to identify 166 protein spots representing 139 different proteins. A considerable strain difference was observed in the proteomic images between strains ATCC 14067 and ATCC 13032 grown under the glutamic acid production conditions, suggesting the importance of strain-specific reference map for proteomic analysis. [source] Proteomic analysis to characterize differential mouse strain sensitivity to cadmium-induced forelimb teratogenesis,BIRTH DEFECTS RESEARCH, Issue 4 2008Haiyan Chen Abstract BACKGROUND: Cadmium ion (Cd2+) is a ubiquitous environmental contaminant, and it is a potent teratogen in mice. An intraperitoneal dose of 4 mg/kg of CdCl2 at gestational day 9 causes forelimb ectrodactyly in the C57BL/6N mouse strain, but the SWV/Fnn strain is resistant. The objective of this study was to identify differentially displayed proteins in two target tissues for cadmium teratogenesis, and to derive hypotheses regarding the mechanisms involved in the murine strain difference in Cd-induced forelimb ectrodactyly. METHODS: The global proteomics strategy used two-dimensional polyacrylamide gel electrophoresis for protein separation, and MALDI-TOF-MS and LC-MS/MS for protein identification, to compare and identify proteins in forelimb buds and yolk sacs from the two mouse strains following Cd administration. RESULTS: More than 1,000 protein spots were detected by two-dimensional polyacrylamide gel electrophoresis in day 10.0 mouse forelimb buds and yolk sacs. Thirty-eight proteins had identifiable differences in abundance levels in Cd-treated forelimb buds between the two strains. Of those 38 proteins, 14 could be associated with the unfolded protein response process and seven are associated with actin polymerization. The proteins that were found to be differentially abundant between the strains in yolk sacs that were exposed to CdCl2 were predominantly different than the proteins detected differentially in the limb buds of the two strains with an overlap of approximately 20%. CONCLUSIONS: These patterns of differentially displayed proteins rationalize a hypothesis that the differential murine strain response to cadmium-induced forelimb ectrodactyly is due to differences in their pathways for the unfolded protein response and/or actin polymerization. Birth Defects Research (Part A), 2008. © 2008 Wiley-Liss, Inc. [source] Altered localization of gene expression in both ectoderm and mesoderm is associated with a murine strain difference in retinoic acid,induced forelimb ectrodactyly,BIRTH DEFECTS RESEARCH, Issue 6 2007Hirohito Shimizu Abstract BACKGROUND: Defects in digit number or fusion as a teratogenic response are well documented in humans and intensively studied in various mouse models. Maternal exposure to excess levels of all- trans -retinoic acid (RA) at gestational day 9.5 induces postaxial ectrodactyly (digit loss) in the murine C57BL/6N strain but not in the SWV/Fnn strain. METHODS: Whole-mount in situ hybridization was used to examine the differential expression of limb patterning genes at the transcriptional level between the two mouse strains following the maternal exposure to a teratogenic level of RA. The detection of a gene with altered expression was followed by either the evaluation of other genes that were synexpressed or with an assessment of downstream genes. RESULTS: In the C57BL/6N limb bud following maternal RA administration, gene-specific perturbations were observed within hours of the RA injection in the posterior pre-AER (apical ectodermal ridge) (Fgf8, Dlx3, Bmp4, Sp8, but not Dlx2 or p63), whereas these genes were normally expressed in the SWV/Fnn limb bud. Furthermore, although RA caused comparable reductions of Shh expression between the strains in the 12 h after administration, some Shh downstream genes were differentially expressed (e.g., Gli1, Ptc, and Hoxd13), whereas others were not (e.g., Fgf4, Bmp4, and Gremlin). CONCLUSIONS: It is proposed that altered gene expression in both pre-AER and mesoderm is involved in the pathogenesis of postaxial digit loss, and that because the alterations in the pre-AER occur relatively early in the temporal sequence of events, those changes are candidates for an initiating factor in the malformation. Birth Defects Research (Part A) 2007. © 2007 Wiley-Liss, Inc. [source] Hippocampal gene expression profiling across eight mouse inbred strains: towards understanding the molecular basis for behaviourEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2004Cathy Fernandes Abstract Mouse inbred strains differ in many aspects of their phenotypes, and it is known that gene expression does so too. This gives us an opportunity to isolate the genetic aspect of variation in expression and compare it to other phenotypic variables. We have investigated these issues using an eight-strain expression profile comparison with four replicates per strain on Affymetrix MGU74av2 GeneChips focusing on one well-defined brain tissue (the hippocampus). We identified substantial strain-specific variation in hippocampal gene expression, with more than two hundred genes showing strain differences by a very conservative criterion. Many such genetically driven differences in gene expression are likely to result in functional differences including differences in behaviour. A large panel of inbred strains could be used to identify genes functionally involved in particular phenotypes, similar to genetic correlation. The genetic correlation between expression profiles and function is potentially very powerful, especially given the current large-scale generation of phenotypic data on multiple strains (the Mouse Phenome Project). As an example, the strongest genetic correlation between more than 200 probe sets showing significant differences among our eight inbred strains and a ranking of these strains by aggression phenotype was found for Comt, a gene known to be involved in aggression. [source] Rat strain differences in peripheral and central serotonin transporter protein expression and functionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003Francesca Fernandez Abstract Female Fischer 344 (F344) rats have been shown to display increased serotonin transporter (5-HTT) gene expression in the dorsal raphe, compared to female Lewis (LEW) rats. Herein, we explored, by means of synaptosomal preparations and in vivo microdialysis, whether central, but also peripheral, 5-HTT protein expression/function differ between strains. Midbrain and hippocampal [3H]paroxetine binding at the 5-HTT and hippocampal [3H]serotonin (5-HT) reuptake were increased in male and female F344 rats, compared to their LEW counterparts, these strain differences being observed both in rats of commercial origin and in homebred rats. Moreover, in homebred rats, it was found that these strain differences extended to blood platelet 5-HTT protein expression and function. Saturation studies of midbrain and hippocampal [3H]paroxetine binding at the 5-HTT, and hippocampal and blood platelet [3H]5-HT reuptake, also revealed significant strain differences in Bmax and Vmax values. Although F344 and LEW rats differ in the activity of the hypothalamo-pituitary-adrenal (HPA) axis, manipulations of that axis revealed that the strain differences in hippocampal [3H]paroxetine binding at 5-HTTs and [3H]5-HT reuptake were not accounted for by corticosteroids. Hippocampal extracellular 5-HT levels were reduced in F344 rats, compared to LEW rats, with the relative, but not the absolute, increase in extracellular 5-HT elicited by the local administration of citalopram being larger in F344 rats. Because the aforementioned strain differences did not lie in the coding sequences of the 5-HTT gene, our results open the promising hypothesis that F344 and LEW strains model functional polymorphisms in the promoter region of the human 5-HTT gene. [source] Strain differences in ,1 receptor-mediated behaviours are related to neurosteroid levelsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2002Vân-Ly Phan Abstract The sigma1 (,1) receptor exerts a potent neuromodulatory role in the brain with relevant consequences in memory processes, response to stress, depression and pharmacodependence. Its precise endogenous ligand is not yet identified but the ,1 receptor appears to be one target for the nongenomic rapid effects of neuroactive steroids in the brain. The aim of the present study was to establish whether differences in ,1 receptor-mediated behaviours could be observed among mouse strains, in relation with differences in either ,1 receptor expression or steroid levels. The ,1 -receptor immunohistochemical distribution appeared similar between Swiss and C57BL/6 strains in all the brain structures examined. The levels of in vivo[3H](+)-SKF-10 047 binding to ,1 receptors were lower in Swiss than in C57BL/6. Adrenalectomy/castration significantly increased [3H](+)-SKF-10 047 binding only in Swiss. The behavioural efficacy of the selective ,1 agonists igmesine and PRE-084 , reversion of the scopolamine-induced amnesia in the passive avoidance test; diminution of the immobility duration in the forced swimming test , were significantly higher in C57BL/6 than in Swiss. Steroid levels were measured in the brain in basal conditions and after stress. C57BL/6 mice presented in both conditions, the lowest progesterone levels, this steroid acting as an endogenous ,1 antagonist. Collectively, the results suggested that strain differences in neuroactive steroid and particularly, progesterone, biosynthesis and sensitivity may contribute to the differential behavioural efficacy of ,1 -receptor ligands. Noteworthy, these observations are coherent with strain differences observed in the intensity of cocaine-induced reward properties, known to critically involve the ,1 receptor. [source] Strain differences in the behavioural outcome of neonatal ventral hippocampal lesions are determined by the postnatal environment and not genetic factorsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2001Graham K. Wood Abstract It has been demonstrated that not only do rats neonatally lesioned in the ventral hippocampus (VH) develop behavioural hypersensitivity to amphetamine postpubertally, but also that the expression of the sensitivity is strain specific. For example, excitotoxic VH lesions at postnatal day (PD) 7 lead to significant increases in amphetamine-induced locomotion in postpubertal Fischer rats, but not in Lewis rats. However, as it is likely that the effect of strain differences are due to a combination of genetics and environment, we examined the contributions of the environment of the pups in determining the behavioural outcome following neonatal VH lesions. Fisher and Lewis rat pups were cross-fostered at birth, and then at PD7 lesioned bilaterally in the VH with ibotenic acid. anova analysis of postpubertal amphetamine-induced locomotor data revealed a significant effect of the strain of the dams raising the pups but no effect of the strain of the pup. In addition, a post hoc analysis revealed that lesioned Fisher or Lewis rats raised by Fisher, but not those raised by Lewis, dams demonstrated amphetamine-induced hyperlocomotion relative to nonlesioned controls. Observations of the maternal behaviour of Fischer and Lewis dams revealed significant differences in the frequency of arched-back nursing between the two strains. Interestingly, a correlation of the frequency of arched back nursing vs novelty- or amphetamine-induced locomotion revealed that the lesioned rats were significantly more affected by increases in arched-back nursing compared to the controls. The results suggest that the genetic background of the pups does not significantly affect the behavioural outcome following neonatal VH lesions; however, the results do suggest an important role of early environmental variables on the behavioural outcome of neonatal VH lesions. [source] Marker-assisted dissection of genetic influences on motor and neuroendocrine sensitization to cocaine in ratsGENES, BRAIN AND BEHAVIOR, Issue 3 2009L. F. Vendruscolo This study investigated genetic influences on behavioral and neuroendocrine responses to cocaine sensitization. We used male and female rats of the inbred strains Lewis (LEW) and spontaneously hypertensive rats (SHR), which display genetic differences in stress-related responses. The influence of two quantitative trait loci (QTL; Ofil1 and Ofil2 on chromosomes 4 and 7), which modulate stress reactivity in rats, on the effects of cocaine was also investigated through the use of recombinant lines (derived from a LEW × SHR intercross) selected by their genotype at Ofil1 and Ofil2. Animals were given repeated cocaine or saline injections and tested for locomotion (induction of sensitization). Two weeks later, all animals were challenged with cocaine, and locomotion and corticosterone levels were measured (expression of sensitization). Results indicated that male SHR rats showed more behavioral sensitization than LEW rats, whereas no strain differences in sensitization were seen among females. When challenged with cocaine, LEW and SHR rats of both sexes pretreated with cocaine showed behavioral sensitization compared with saline pretreated animals; however, only LEW rats displayed an increase in the corticosterone levels. Ofil1 was found to influence the induction of sensitization in males and Ofil2 modulated the locomotor effect of cocaine in females. This study provides evidence of a genotype-dependent relationship between the induction and expression of cocaine sensitization, and between the behavioral and neuroendocrine responses induced by cocaine. Moreover, the Ofil1 and Ofil2 loci may contain one or more genes that control the behavioral effects of cocaine in rats. [source] Mouse inbred strain differences in ethanol drinking to intoxicationGENES, BRAIN AND BEHAVIOR, Issue 1 2007J. S. Rhodes Recently, we described a simple procedure, Drinking in the Dark (DID), in which C57BL/6J mice self-administer ethanol to a blood ethanol concentration (BEC) above 1 mg/ml. The test consists of replacing the water with 20% ethanol in the home cage for 4 h early during the dark phase of the light/dark cycle. Three experiments were conducted to explore this high ethanol drinking model further. In experiment 1, a microanalysis of C57BL/6J behavior showed that the pattern of ethanol drinking was different from routine water intake. In experiment 2, drinking impaired performance of C57BL/6J on the accelerating rotarod and balance beam. In experiment 3, 12 inbred strains were screened to estimate genetic influences on DID and correlations with other traits. Large, reliable differences in intake and BEC were detected among the strains, with C57BL/6J showing the highest values. Strain means were positively correlated with intake and BEC in the standard (24 h) and a limited (4 h) two-bottle ethanol vs. water test, but BECs reached higher levels for DID. Strain mean correlations with other traits in the Mouse Phenome Project database supported previously reported genetic relationships of high ethanol drinking with low chronic ethanol withdrawal severity and low ethanol-conditioned taste aversion. We extend these findings by showing that the correlation estimates remain relatively unchanged even after correcting for phylogenetic relatedness among the strains, thus relaxing the assumption that the strain means are statistically independent. We discuss applications of the model for finding genes that predispose pharmacologically significant drinking in mice. [source] Enzymes involved in flavour formation by bacteria isolated from the smear population of surface-ripened cheeseINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2004A G Williams Twenty-five bacterial isolates recovered from the surface population of smear-ripened cheese were assigned phenotypically as Brevibacterium spp., Corynebacterium spp. and Aureobacterium spp. using the Biolog GP2 microplate system and database. The range and activity of hydrolytic enzymes involved in the formation of cheese flavour constituents were monitored in cell-free lysates of the isolates. Esterase activity and the presence of a range of enzymes involved in amino acid release and breakdown was confirmed in all strains examined although there were pronounced interspecies and strain differences in the level of activity detected. Peptidolytic activities present in the smear bacteria included dipeptidyl peptidase and aminopeptidases that cleaved various N-terminal amino acids including proline. Subsequent breakdown of the released aromatic and branched-chain amino acids was mediated by ,-keto acid dependent aminotransferase action and several of the isolates were able to form thiols from sulphur-containing amino acid precursors. It was confirmed that the enzymic activity of the smear population could be manipulated by the use of defined starter cultures comprising selected combinations of smear isolates. The hydrolytic activities of the smear bacteria are involved in the generation of cheese flavour compounds and the enzyme profile is thus an important selection criterion for strains to be evaluated for use in defined surface smear preparations. [source] Efficacy of natamycin for control of growth and ochratoxin A production by Aspergillus carbonarius strains under different environmental conditionsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007Á. Medina Abstract Aims:, To examine the efficacy of natamycin produced by Streptomyces natalensis against strains of Aspergillus carbonarius growth and ochratoxin A (OTA) production under different environmental factors on a grape juice-based medium. Methods and Results:, Detailed studies in the range 0,20 ng ml,1 for control of growth and ochratoxin production by strains of A. carbonarius at 0·98, 0·96 and 0·94 water availabilities (aw) and 15,25°C on a fresh red grape extract medium were examined. Inhibition of growth was depending on temperature and aw level. At 15°C, 5,10 ng ml,1 natamycin was effective in reducing growth almost completely. However, at 20,25°C and all the three aw levels, growth was only slightly inhibited by 5,10 ng ml,1 natamycin. There were strain differences with regard to inhibition of OTA production. At 15°C and 0·98 aw, 10 ng ml,1 was required to inhibit production by >90%. However, at 0·96 and 0·94 aw, almost complete inhibition occurred. At 20°C, OTA production was only significantly inhibited by 10 ng ml,1 natamycin at 0·94 aw. At 0·96 and 0·98 aw, some inhibition occurred with 5,10 ng ml,1, but greater concentrations would be required for effective inhibition. At 25°C, 5 ng ml,1 was effective at all aw levels. However, at 15°C and 25°C and a wide range of aw levels, natamycin effectively controlled OTA production. Conclusions:, Natamycin appears to be a very effective for controlling growth and OTA production by strains of A. carbonarius over a range of aw and temperature conditions on grape-based media. Significance and Impact of the Study:, This is the first detailed study to demonstrate the impact of natamycin against A. carbonarius. This study suggests that use of natamycin at 50,100 ng ml,1 can give complete inhibition of growth of A. carbonarius and OTA production over a range of environmental conditions. Natamycin could be an important component of a system to prevent OTA contamination of wine as well during the drying and production of vine fruits. [source] Glutamate dehydrogenase activity in lactobacilli and the use of glutamate dehydrogenase-producing adjunct Lactobacillus spp. cultures in the manufacture of cheddar cheeseJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2006A.G. Williams Abstract Aims:, The study was undertaken to investigate the occurrence of glutamate dehydrogenase activity in different species of lactobacilli, and to determine, in a series of cheese-making trials, the effects of glutamate dehydrogenase-producing adjunct cultures on sensory attribute development during the maturation of cheddar cheese. Methods and Results:, The presence of dehydrogenase activity with glutamate as substrate was monitored in cell lysates of >100 strains from 30 different species of lactobacilli using a qualitative colorimetric plate screening assay. Activity was detectable in 25 of the 29 representative species obtained from culture collections and in 12 of the 13 non-starter species isolated from cheese. There were pronounced interspecies and strain differences in the occurrence, level and pyridine nucleotide specificity of the glutamate dehydrogenase activity detected. Among the non-starter lactobacilli the highest frequency of enzyme occurrence and activity was detected in the Lactobacillus plantarum isolates. The establishment of glutamate dehydrogenase-producing adjunct strains in the predominant population of lactobacilli in the cheese curd affected the formation of a number of volatile compounds in ripening cheddar cheese, while the presence of Lact. plantarum strains, in particular, was associated with an intensification and acceleration of aroma and flavour development during the maturation period. Conclusions:, Glutamate dehydrogenase formation by lactobacilli is a strain-dependent metabolic attribute, and adjunct cultures expressing the activity that are able to proliferate during cheese ripening have a positive impact on the rate of development and the intensity of cheddar cheese aroma and flavour development. Significance and Impact of the Study:, It has been demonstrated that some strains of glutamate dehydrogenase-producing lactobacilli have potential use as adjunct cultures to accelerate and intensify aroma and flavour formation during the manufacture of cheddar and, by analogy, other similar varieties of cheese. The importance of phenotypic discriminative monitoring of the dominant lactobacilli present during ripening to confirm adjunct establishment and population complexity was highlighted as was the requirement to establish the metabolic attributes of the non-starter population in uninoculated control cheeses in comparative trials. [source] Withdrawal Severity After Chronic Intermittent Ethanol in Inbred Mouse StrainsALCOHOLISM, Issue 9 2010Pamela Metten Background:, To study withdrawal, ethanol is usually administered chronically without interruption. However, interest has recurred in models of episodic exposure. Increasing evidence suggests that chronic intermittent exposure to ethanol leads to a sensitization effect in both withdrawal severity and ethanol consumption. The goal of the present study was to examine mouse inbred strain differences in withdrawal severity following chronic intermittent exposure using the handling-induced convulsion as the behavioral endpoint. We also sought to compare the withdrawal responses of inbred strains across acute, chronic continuous, and chronic intermittent exposure regimens. Methods:, Male mice from 15 standard inbred strains were exposed to ethanol vapor for 16 hours each day for 3 days and removed to an air chamber during the intervening 8 hours. Mice in the control groups were handled the same, except that they were exposed only to air. Daily blood ethanol concentrations were averaged for each mouse to estimate total dose of ethanol experienced. Results:, Across strains, mice had an average daily blood ethanol concentration (BEC) of 1.45 ± 0.02 mg/ml and we restricted the range of this value to 1.00,2.00 mg/ml. To evaluate strain differences, we divided data into two dose groups based on BEC, low dose (1.29 ± 0.1 mg/ml) and high dose (1.71 ± 0.02 mg/ml). After the third inhalation exposure, ethanol-exposed and air-exposed groups were tested hourly for handling-induced convulsions for 10 hour and at hour 24 and 25. Strains differed markedly in the severity of withdrawal (after subtraction of air control values) in both dose groups. Conclusion:, The chronic intermittent exposure paradigm is sufficient to elicit differential withdrawal responses across nearly all strains. Data from the high-dose groups correlated well with withdrawal data derived from prior acute (single high dose) and chronic continuous (for 72 hours) ethanol withdrawal studies, supporting the influence of common genes on all three responses. [source] Strain Differences in Behavioral Inhibition in a Go/No-go Task Demonstrated Using 15 Inbred Mouse StrainsALCOHOLISM, Issue 8 2010Noah R. Gubner Background:, High levels of impulsivity have been associated with a number of substance abuse disorders including alcohol abuse. Research has not yet revealed whether these high levels predate the development of alcohol abuse. Methods:, The current study examined impulsivity in 15 inbred strains of mice (A/HeJ, AKR/J, BALB/cJ, C3H/HeJ, C57BL/6J, C57L/J, C58/J, CBA/J, DBA/1J, DBA/2J, NZB/B1NJ, PL/J, SJL/J, SWR/J, and 129P3/J) using a Go/No-go task, which was designed to measure a subject's ability to inhibit a behavior. Numerous aspects of response to ethanol and other drugs of abuse have been examined in these strains. Results:, There were significant strain differences in the number of responses made during the No-go signal (false alarms) and the extent to which strains responded differentially during the Go and No-go signals (d,). The rate of responding prior to the cue did not differ among strains, although there was a statistically significant correlation between false alarms and precue responding that was not related to basal activity level. Interstrain correlations suggested that false alarms and rate of responding were associated with strain differences in ethanol-related traits from the published literature. Conclusions:, The results of this study do support a link between innate level of impulsivity and response to ethanol and are consistent with a genetic basis for some measures of behavioral inhibition. [source] Alcohol, Cocaine, and Brain Stimulation-Reward in C57Bl6/J and DBA2/J MiceALCOHOLISM, Issue 1 2010Eric W. Fish Background:, Pleasure and reward are critical features of alcohol drinking that are difficult to measure in animal studies. Intracranial self-stimulation (ICSS) is a behavioral method for studying the effects of drugs directly on the neural circuitry that underlies brain reward. These experiments had 2 objectives: first, to establish the effects of alcohol on ICSS responding in the C57Bl6/J (C57) and DBA2/J (DBA) mouse strains; and second, to compare these effects to those of the psychostimulant cocaine. Methods:, Male C57 and DBA mice were implanted with unipolar stimulating electrodes in the lateral hypothalamus and conditioned to spin a wheel for reinforcement by the delivery of rewarding electrical stimulation (i.e., brain stimulation-reward or BSR). Using the curve-shift method, the BSR threshold (,0) was determined immediately before and after oral gavage with alcohol (0.3, 0.6, 1.0, 1.7 g/kg) or water. Blood alcohol concentration (BAC) was measured to determine the influence of alcohol metabolism on BSR threshold. Separately, mice were administered cocaine (1.0, 3.0, 10.0, 30.0 mg/kg) or saline intraperitoneally. Results:, In C57 mice, the 0.6 g/kg dose of alcohol lowered BSR thresholds by about 20%, during the rising (up to 40 mg/dl), but not falling, phase of BAC. When given to the DBA mice, alcohol lowered BSR thresholds over the entire dose range; the largest reduction was by about 50%. Cocaine lowered BSR thresholds in both strains. However, cocaine was more potent in DBA mice than in C57 mice as revealed by a leftward shift in the cocaine dose,response curve. For both alcohol and cocaine, effects on BSR threshold were dissociable from effects on operant response rates. Conclusions:, In C57 and DBA mice, reductions in BSR threshold reflect the ability of alcohol to potentiate the neural mechanisms of brain reward. The DBA mice are more sensitive to the reward-potentiating effects of both alcohol and cocaine, suggesting that there are mouse strain differences in the neural mechanisms of brain reward that can be measured with the ICSS technique. [source] N -methyl-d-aspartate Receptor Responses Are Differentially Modulated by Noncompetitive Receptor Antagonists and Ethanol in Inbred Long-Sleep and Short-Sleep Mice: Behavior and ElectrophysiologyALCOHOLISM, Issue 12 2000Taleen Hanania Background: Short-sleep (SS) mice exhibit higher locomotor activity than do long-sleep (LS) mice when injected with low doses of ethanol or the noncompetitive N -methyl-D-aspartate receptor (NMDAR) antagonist MK-801 (dizocilpine). SS mice also have higher densities of brain NMDARs. However, two strains of LS X SS recombinant inbred (RI) mice also show differential activation to ethanol and MK-801, but have similar numbers of NMDARs. Here we used inbred LS (ILS) and SS (ISS) mice to investigate further the relationship between NMDARs and sensitivity to the stimulant effects of low doses of ethanol. Methods: Open field activity and spontaneous alternations were measured after saline or drug injection. [3H]MK-801 binding parameters were determined in hippocampus, cortex, striatum, and nucleus accumbens. Extracellular field excitatory postsynaptic potentials (fEPSPs) were recorded in the CA1 region of hippocampal slices. Results: Systemic injection of either ethanol or MK-801 increased locomotor activity to a greater extent in ISS mice than in ILS mice. The competitive NMDAR antagonist 2-carboxypiperazin-4-yl-propyl-1,1phosphonic acid (±CPP) depressed activity of ILS, but not ISS, mice. No strain differences were observed in spontaneous alternations or in the number or affinity of NMDARs in the brain regions examined. Likewise, the magnitudes of hippocampal NMDAR-mediated fEPSPs were similar in ILS and ISS mice and were inhibited to the same extent by a competitive NMDAR antagonist. However, both ethanol and the NMDAR NR2B receptor antagonist ifenprodil inhibited the late component of hippocampal NMDAR fEPSPs to a greater extent in ISS, than in ILS, mice. Conclusions: Differential ethanol- and MK-801-induced behavioral activation in ILS and ISS mice was not associated with differences in NMDAR number. Nonetheless, pharmacological differences in hippocampal NMDAR responsiveness suggest that ISS mice express NMDARs that have a greater sensitivity to noncompetitive, but not competitive, NMDAR antagonists. These differences, which may reflect differences in NMDAR subunit composition, could underlie the differential responsiveness to low doses of ethanol in ILS and ISS mice. [source] Differences in Growth and Nutrient Efficiency Between and Within Two Channel Catfish Ictalurus punctatus StrainsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2005Brian. A 6-wk growth study was conducted comparing fingerling (mean weight = 24.7 g) USDA103 strain channel catfish Ictalurus punctatus to Norris strain channel catfish in an effort to determine strain differences in growth and nutrient efficiency. Variability within strains also was assessed by randomly selecting four families from each strain for comparison. On average, USDA103 fish gained significantly (P < 0.05) more weight (51.2 vs. 31.7 g) and length (4.7 vs. 4.1 cm) compared to Norris strain catfish. Significantly (P < 0.05) greater feed consumption (56.6 vs 41.3 g) and feed efficiency (95.7 vs. 89.9) for USDA103 catfish were also observed. Family differences in weight and length gain and feed intake were significant (P < 0.05) among USDA103 families; whereas, only differences in feed intake and feed efficiency were significant (P < 0.05) among Norris families. Nitrogen retention was higher (P < 0.05) for the Norris strain catfish (35.6%) relative to the USDA103 strain average (31.0%). The results of this study reiterate the superior growth and feed efficiency of the USDA103 strain of channel catfish. Observed differences among USDA103 families suggest that further improvements in weight gain can be made through selective breeding; however, improvements in feed and protein efficiency may be difficult. [source] Microsatellite loci for the fungus Ascosphaera apis: cause of honey bee chalkbrood diseaseMOLECULAR ECOLOGY RESOURCES, Issue 3 2009STEPHEN A. REHNER Abstract The fungus Ascosphaera apis is a worldwide fungal pathogen of honey bees. To provide tools for understanding the dispersal history of this pathogen, strain differences in virulence, and host,pathogen interactions, we used the draft genome assembly of A. apis to develop microsatellite loci for this species. We present testing results for 25 scorable loci revealing two to eight alleles per locus in a survey of Maryland isolates of this fungus. [source] Growth response of Nile tilapia fry to salinity stress in the presence of an ,internal reference' fishAQUACULTURE RESEARCH, Issue 7 2005Zubaida U Basiao Abstract Growth of three strains of Oreochromis niloticus L. fry exposed to salinity stress in the presence of an internal reference fish were compared. The Central Luzon State University (CLSU) strain was obtained from the Freshwater Aquaculture Center, CLSU, Philippines. The ISRAEL strain was acquired from the Philippine government's Bureau of Fisheries and Aquatic Resources National Freshwater Fisheries Technology Center (BFAR-NFFTC), Munoz, Nueva Ecija. The National Inland Fisheries Institute (NIFI) strain was obtained from the NIFI, Bangkok, Thailand. Eight to nine full-sib families (replicates) per strain were split into two groups. One group was grown in freshwater for 2 weeks, acclimated to 32 ppt and reared for 2 weeks and finally grown in freshwater for another 2 weeks. Another group was contemporaneously grown in freshwater polyethylene tanks for 6 weeks. Each replicate family included a size-matched internal reference population of red tilapia strain. Two-way analysis of variance (anova) revealed no significant strain differences (P=0.081; r2=0.106). However, analysis of covariance with the internal reference strain used as a covariate showed significant (P=0.049; r2=0.638) strain effects on specific growth (based on standard length measurements). The ISRAEL strain showed consistently better growth rate in both saline and freshwater environments than the NIFI and CLSU strains. We estimated the statistical power of the two-way anova (,=,(k,,1)(factor MS,s2)/(k,s2); Zar 1984) to be ,0.30. There was a 70% probability of a Type II error and no true difference in the growth of the three strains was detected. The use of internal reference strain as a covariate improved the r2 from 0.106 to 0.638 and increased the efficiency of the test in detecting a true difference. Other strain comparison studies in our laboratory at the Southeast Asian Fisheries Development Center Aquaculture Department showed that the ISRAEL strain shows better growth than the NIFI and CLSU strains in a crowding stress tolerance experiment, when fed only with rice bran and under restrictive feeding regimes. [source] Mouse Strain Susceptibility to Diethylnitrosamine Induced Hepatocarcinogenesis Is Cell Autonomous Whereas Sex-susceptibility Is Due to the Micro-environment: Analysis with C3H , BALB/c Sexually Chimeric MiceCANCER SCIENCE, Issue 7 2000Tetsuya Tsukamoto In man, liver cancer is on the increase, especially in males. Sex differences also exist in rodent models. To elucidate the mechanisms, chimeric mice were produced by amalgamation of early embryos from high and low hepatocarcinogen-susceptible strains, C3H and BALB/c. Tumor formation was initiated with 10 mg/kg of diethylnitrosamine at the ages of 7 and 14 days and mice were sacrificed at 30 and 45 weeks. The chimeras were classified into XY,XY, XY,XX, XX,XY, and XX,XX in terms of sex chromosomes by means of polymerase chain reaction-simple sequence length polymorphism analysis (SSLP) using Y chromosome-specific Sry primers in combination with the D3Mit21 marker. Liver lesions were analyzed histopathologically, by immunostaining using a C3H strain-specific antibody and by DNA in situ hybridization with the Y chromosomespecific digoxigenin-labeled Y353/B probe. Sex and strain genotyping by SSLP analysis matched histological observations, confirming the reliability of our system. The strain differences in liver tumor numbers of each strain type in XY,XY and XX,XX subtypes of C3H,BALB/c chimeras were retained well (P< 0.0001 and P< 0.001, respectively), indicating a minimum influence of the C3H or BALB/c surrounding milieu on development of individual lesions. On the other hand, significant promotion of XX cell tumors was evident in phenotypically male sexually chimeric XY,XX and XX,XY chimeras for both C3H (P< 0.02) and BALB/c (P< 0.01) lesions compared to the XX,XX case. The results suggest the presence of hormonal or micro-environmental factors specific for males, which are not caused cell-autonomously. Basic strain differences, however, are determined by intrinsic genetic factors rather than the strain-dependent micro-environment [source] | |||||||||||||||||||||||||||||||