Association between genetic variants of the metabotropic glutamate receptor 3 (GRM3) and cognitive set shifting in healthy individuals

Set‐shifting and maintenance are complex cognitive processes, which are often impaired in schizophrenia. The genetic basis of these processes is poorly understood. We aimed to investigate the association between genetic variants of the metabotropic glutamate receptor 3 (GRM3) and cognitive set‐shifting in healthy individuals. The relationship between 14 selected single nucleotide polymorphisms (SNPs) of the GRM3 gene and cognitive set‐shifting as measured by perseverative errors using the modified card sorting test (MCST) was analysed in a sample of N = 98 young healthy individuals (mean age in years: 22.7 ± 0.19). Results show that SNP rs17676277 is related to the performance on the MCST. Subjects with the TT genotype showed significantly less perseverative errors as compared with the AA (P = 0.025) and AT (P = 0.0005) and combined AA/AT genotypes (P = 0.0005). Haplotype analyses suggest the involvement of various SNPs of the GRM3 gene in perseverative error processing in a dominant model of inheritance. The findings strongly suggest that the genetic variation (rs17676277 and three haplotypes) in the metabotropic GRM3 is related to cognitive set‐shifting in healthy individuals independent of working memory. However, because of a relatively small sample size for a genetic association study, the present results are tentative and require replication.     

Effect of Proximity to a Cattle Feedlot on Escherichia coli O157:H7 Contamination of Leafy Greens and Evaluation of the Potential for Airborne Transmission

The impact of proximity to a beef cattle feedlot on Escherichia coli O157:H7 contamination of leafy greens was examined. In each of 2 years, leafy greens were planted in nine plots located 60, 120, and 180 m from a cattle feedlot (3 plots at each distance). Leafy greens (270) and feedlot manure samples (100) were collected six different times from June to September in each year. Both E. coli O157:H7 and total E. coli bacteria were recovered from leafy greens at all plot distances. E. coli O157:H7 was recovered from 3.5% of leafy green samples per plot at 60 m, which was higher (P < 0.05) than the 1.8% of positive samples per plot at 180 m, indicating a decrease in contamination as distance from the feedlot was increased. Although E. coli O157:H7 was not recovered from air samples at any distance, total E. coli was recovered from air samples at the feedlot edge and all plot distances, indicating that airborne transport of the pathogen can occur. Results suggest that risk for airborne transport of E. coli O157:H7 from cattle production is increased when cattle pen surfaces are very dry and when this situation is combined with cattle management or cattle behaviors that generate airborne dust. Current leafy green field distance guidelines of 120 m (400 feet) may not be adequate to limit the transmission of E. coli O157:H7 to produce crops planted near concentrated animal feeding operations. Additional research is needed to determine safe set-back distances between cattle feedlots and crop production that will reduce fresh produce contamination.     

Protective effect of bixin on carbon tetrachloride-induced hepatotoxicity in rats

Background

The liver is an important organ for its ability to transform xenobiotics, making the liver tissue a prime target for toxic substances. The carotenoid bixin present in annatto is an antioxidant that can protect cells and tissues against the deleterious effects of free radicals. In this study, we evaluated the protective effect of bixin on liver damage induced by carbon tetrachloride (CCl₄) in rats.

Results

The animals were divided into four groups with six rats in each group. CCl₄ (0.125 mL kg^-1 body wt.) was injected intraperitoneally, and bixin (5.0 mg kg^-1 body wt.) was given by gavage 7 days before the CCl₄ injection. Bixin prevented the liver damage caused by CCl₄, as noted by the significant decrease in serum aminotransferases release. Bixin protected the liver against the oxidizing effects of CCl₄ by preventing a decrease in glutathione reductase activity and the levels of reduced glutathione and NADPH. The peroxidation of membrane lipids and histopathological damage of the liver was significantly prevented by bixin treatment.

Conclusion

Therefore, we can conclude that the protective effect of bixin against hepatotoxicity induced by CCl₄ is related to the antioxidant activity of the compound.     

Long non‐coding RNAs in melanoma

Melanoma is the most lethal cutaneous cancer with a highly aggressive and metastatic phenotype. While recent genetic and epigenetic studies have shed new insights into the mechanism of melanoma development, the involvement of regulatory non‐coding RNAs remain unclear. Long non‐coding RNAs (lncRNAs) are a group of endogenous non‐protein‐coding RNAs with the capacity to regulate gene expression at multiple levels. Recent evidences have shown that lncRNAs can regulate many cellular processes, such as cell proliferation, differentiation, migration and invasion. In the melanoma, deregulation of a number of lncRNAs, such as HOTAIR, MALAT1, BANCR, ANRIL, SPRY‐IT1 and SAMMSON, have been reported. Our review summarizes the functional role of lncRNAs in melanoma and their potential clinical application for diagnosis, prognostication and treatment.     

Variable agronomic practices, cultivar, strain source and initial contamination dose differentially affect survival of Escherichia coli on spinach

Aims: Greenhouse and field trials were conducted under different agronomic practices and inoculum doses of environmental Escherichia coli and attenuated E. coli O157:H7, to comparatively determine whether these factors influence their survival on leaves and within the rhizosphere. Methods and Results: Hydroponic conditions: E. coli spray‐inoculated at log 4 CFU ml^?1 was recovered from leaf surfaces at a mean population of 1·6 log CFU g^?1 at 15 days. E. coli O157:H7 sprayed at log 2 or 4 CFU ml^?1 levelled off on spinach leaf surfaces at a mean average population of 1·4 log CFU g^?1 after 14 days, regardless of initial dose. Quantitative recovery was inconsistent across leaf developmental age. Field conditions: Average populations of E. coli O157:H7 spray‐inoculated at log 1·45 or 3·4 CFU m^?2 levelled off at log 1·2 CFU g^?1 over a 14‐day period. Pathogen recovery from leaves was inconsistent when compared to regularly positive detection on basal shoot tissue. Pathogen recovery from soil was inconsistent among sampling locations. Moisture content varied up to 40% DW and was associated with 50% (P < 0·05) decrease in positive locations for E. coli O157:H7 but not for E. coli. Conclusions: Overall, similar populations of environmental E. coli and E. coli O157:H7 were recovered from plants despite differences in inoculum dose and agronomic conditions. Strain source had a significant impact on the quantitative level and duration of survival on leaves and in soil. Water availability appeared to be the determinant factor in survival of E. coli and E. coli O157:H7; however, E. coli showed greater environmental fitness. Significance and Impact of the Study: Persistence of surrogate, indicator E. coli and E. coli O157:H7, irrespective of variable growing conditions in spinach is predominantly limited by water availability, strain source and localization within the plant. These findings are anticipated to ultimately be adopted into routine and investigative pathogen testing protocols and mechanical harvest practices of spinach.     

Women's Greater Ability to Perceive Happy Facial Emotion Automatically: Gender Differences in Affective Priming

There is evidence that women are better in recognizing their own and others' emotions. The female advantage in emotion recognition becomes even more apparent under conditions of rapid stimulus presentation. Affective priming paradigms have been developed to examine empirically whether facial emotion stimuli presented outside of conscious awareness color our impressions. It was observed that masked emotional facial expression has an affect congruent influence on subsequent judgments of neutral stimuli. The aim of the present study was to examine the effect of gender on affective priming based on negative and positive facial expression. In our priming experiment sad, happy, neutral, or no facial expression was briefly presented (for 33 ms) and masked by neutral faces which had to be evaluated. 81 young healthy volunteers (53 women) participated in the study. Subjects had no subjective awareness of emotional primes. Women did not differ from men with regard to age, education, intelligence, trait anxiety, or depressivity. In the whole sample, happy but not sad facial expression elicited valence congruent affective priming. Between-group analyses revealed that women manifested greater affective priming due to happy faces than men. Women seem to have a greater ability to perceive and respond to positive facial emotion at an automatic processing level compared to men. High perceptual sensitivity to minimal social-affective signals may contribute to women's advantage in understanding other persons' emotional states.     

Transmission via plants of an insect pathogenic bacterium that does not multiply or move in plants

A bacterial parasite (designated as BEV) of the leafhopper Euscelidius variegatus, which is passed transovarially to offspring, was transmitted from insect to insect via feeding of the insects in plants. The rate of bacterial infection of leafhoppers fed upon plants that had previously been exposed to BEV-infected leafhoppers declined with an increase in the time that infected leafhoppers had been off rye grass. Transmission of BEV also occurred on sugar beet and barley but not celery. The bacterium was also transmitted to and acquired from membrane-encased artificial diets. There was no evidence that the bacterium was transmitted via plant surfaces, but transmission and direct culture assays from plants indicated that the bacterium did not multiply or move within plants. This parasite-host relationship may represent a primitive stage in either the evolution of intracellular symbiosis with its insect host or to alternative parasitization of plant and insect hosts via insect transmission, as is the case for insect-vectored plant pathogens.Correspondence to: A.H. Purcell.     

Influence of Repressive Coping Style on Cortical Activation during Encoding of Angry Faces

Background

Coping plays an important role for emotion regulation in threatening situations. The model of coping modes designates repression and sensitization as two independent coping styles. Repression consists of strategies that shield the individual from arousal. Sensitization indicates increased analysis of the environment in order to reduce uncertainty. According to the discontinuity hypothesis, repressors are sensitive to threat in the early stages of information processing. While repressors do not exhibit memory disturbances early on, they manifest weak memory for these stimuli later. This study investigates the discontinuity hypothesis using functional magnetic resonance imaging (fMRI).

Methods

Healthy volunteers (20 repressors and 20 sensitizers) were selected from a sample of 150 students on the basis of the Mainz Coping Inventory. During the fMRI experiment, subjects evaluated and memorized emotional and neutral faces. Subjects performed two sessions of face recognition: immediately after the fMRI session and three days later.

Results

Repressors exhibited greater activation of frontal, parietal and temporal areas during encoding of angry faces compared to sensitizers. There were no differences in recognition of facial emotions between groups neither immediately after exposure nor after three days.

Conclusions

The fMRI findings suggest that repressors manifest an enhanced neural processing of directly threatening facial expression which confirms the assumption of hyper-responsivity to threatening information in repression in an early processing stage. A discrepancy was observed between high neural activation in encoding-relevant brain areas in response to angry faces in repressors and no advantage in subsequent memory for these faces compared to sensitizers.