Optimization of exopolysaccharide production by Lactobacillus delbrueckii subsp. bulgaricus RR grown in a semidefined medium

The role of K+ channels in the nitric oxide-independent renal vasodilator effect of acetylcholine (Ach) was examined to address the hypothesis that the mechanism underlying this response was different from that of bradykinin, because an earlier study indicated the possibility of different mediators. We used the rat isolated, perfused kidney that was constricted with phenylephrine and treated with nitroarginine and indomethacin to inhibit nitric oxide synthase and cyclooxygenase, respectively. The nonspecific K+ channel inhibitors, procaine and tetraethylammonium (TEA), reduced vasodilator responses to Ach and cromakalim, but not those to nitroprusside. Glibenclamide, an inhibitor of ATP-sensitive K+ channels, reduced vasodilator responses to cromakalim but did not affect those to Ach or nitroprusside. Charybdotoxin, an inhibitor of Ca(++)-activated K+ channels, reduced vasodilator responses to Ach without affecting those to cromakalim or nitroprusside. Iberiotoxin and apamin, inhibitors of large- and small-conductance Ca(++)-activated K+ channels, respectively, did not reduce vasodilation induced by Ach, cromakalim or nitroprusside. The inhibitor of cytochrome P450, clotrimazole, reduced the renal vasodilator effects of Ach and bradykinin but not those of nitroprusside or SCA 40, an agonist for Ca(++)-activated K+ channels. These results suggest that in the rat kidney, Ach, like bradykinin, utilizes a charybdotoxin-sensitive Ca(++)-activated K+ channel of intermediate conductance to elicit vasodilation and that this effect may be dependent on cytochrome P450 activity.     

Focus of attention mediates the impact of negative affect on altruism.

An experiment with 36 undergraduates tested whether the relationship between negative affect and altruism is mediated by focus of attention. Ss were asked to imagine that a close friend was terminally ill. They were told to attend either to their own reactions or to the reactions of the dying friend. Ss in these conditions did not differ in self-reported negative mood. Moreover, they were "sadder" than Ss in a control condition, who imagined a nontragic event. When subsequently given the opportunity to be anonymous altruists, the other-focused Ss were significantly more helpful than either the self-focused or control Ss. It is suggested that negative moods facilitate altruism among people who are attending to the problems of others, but not among people who attend to their own needs, concerns, and losses. The ethical implications of experiments inducing powerful negative affects are discussed. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for plasmid-associated crystal toxin production in Bacillus thuringiensis subsp. israelensis

Three crystalliferous (Cry+) strains of Bacillus thuringiensis subsp. israelensis (serotype 14) that produce parasporal protein crystals toxic to dipteran larvae and several acrystalliferous (Cry-) mutants, either induced or spontaneously derived from a single Cry+ parent, were examined for the presence of covalently closed circular (CCC) DNA in attempts to correlate toxin production with the presence of a specific plasmid. The plasmid profiles of both Cry+ and Cry- variants were analyzed by both a cleared lysate- and a modified Eckhardt lysate-electrophoresis technique. All of the Cry- mutants derived from the Cry+ parental strain had lost a 4.0- to 4.4-megadalton (Mdal) plasmid. Bioassay data confirmed loss of toxin production by the Cry- variants. All three Cry+ strains, including the parent of the Cry- strains, contained CCC plasmids DNAs of the following approximate molecular weights: 4.0 to 4.4, 5.2 to 6.0, and 11.4 to 13.0 Mdal. One Cry+ strain contained an additional CCC plasmid of 6.7 to 7.2 Mdal. The plasmid patterns for several Cry- derivatives differed in other respects from the pattern for their parent strain. The various Cry+ and Cry- strains could be distinguished either by phenotypical differences in antibiotic sensitivity, crystal production, and toxicity, or by differences in their plasmid profiles.     

Locus of control for positive and negative outcomes.

Performed an experiment in which 107 undergraduates, rated as internals, moderates, and externals on Rotter's Internal–External Locus of Control Scale, worked at a difficult angle-matching task that was purportedly skill determined. Ss were given an instructional set stressing the attainment of a positive outcome or the avoidance of a negative outcome contingent on successful task performance. As predicted, internals outperformed externals only in the negative outcome condition. For positive outcomes, there were no differences in performance. A separate scale (the Steiner Malevolent–Benevolent Questionnaire) designed to measure locus of control for positive and/or negative outcomes successfully identified individuals whose performance was enhanced by the prospect of avoiding a negative outcome and those whose performance was enhanced by the prospect of obtaining a positive outcome. Attribution data collected following bogus success or failure feedback also indicated that internals and externals differed in feelings of control for negative outcomes only. Results support an argument that the Rotter scale is more predictive of responses to negative events. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Job control mediates change in a work reorganization intervention for stress reduction.

This longitudinal, quasi-experiment tested whether a work reorganization intervention can improve stress-related outcomes by increasing people's job control. To this end, the authors used a participative action research (PAR) intervention that had the goal of reorganizing work to increase the extent to which people had discretion and choice in their work. Results indicated that the PAR intervention significantly improved people's mental health, sickness absence rates, and self-rated performance at a 1-year follow-up. Consistent with occupational health psychology theories, increase in job control served as the mechanism, or mediator, by which these improvements occurred. Discussion focuses on the need to understand the mechanism by which work reorganization interventions affect change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparing two burnout interventions: Perceived job control mediates decreases in burnout.

This quasi-experimental study compared the effects of two rehabilitation interventions on burnout and perceived job conditions during a 1-year intervention among female white-collar workers. The participatory intervention (n = 20), involving rehabilitation activities that focused on the individual as well as on individual-organizational levels, assessed exhaustion, cynicism and perceived job control during a 1-year period. Increased job control served as a mechanism through which exhaustion and cynicism decreased in this intervention. The traditional intervention (n = 32), involving rehabilitation activities focusing mainly on the individual level, resulted in a reduction in time pressures during one year. Furthermore, both interventions improved perceived workplace climate. Compared to the traditional approach, the participatory intervention was a more effective strategy for treating burnout. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An ampD gene in Pseudomonas aeruginosa encodes a negative regulator of AmpC beta-lactamase expression

The ampD and ampE genes of Pseudomonas aeruginosa PAO1 were cloned and characterized. These genes are transcribed in the same orientation and form an operon. The deduced polypeptide of P. aeruginosa ampD exhibited more than 60% similarity to the AmpD proteins of enterobacteria and Haemophilus influenzae. The ampD product transcomplemented Escherichia coli ampD mutants to wild-type beta-lactamase expression.     

Characterization of pepR1, a gene coding for a potential transcriptional regulator of Lactobacillus delbrueckii subsp. lactis DSM7290

This article examines the importance of economic factors in physician and other health service utilization among older adults living in Bermuda. Using data drawn from a national survey of 500 Bermudian elders, the findings reveal economic factors to be unrelated to the use of physician services directly, but to be significant determinants of the use of other health services. Need plus non-need factors are related to the use of both physician and other health services. The employer-based system does seem to provide universal access, but factors in addition to need influence the receipt of care.     

A novel phospholipase C delta4 (PLCdelta4) splice variant as a negative regulator of PLC

It has been reported that there are two alternatively spliced variants of phospholipase C-delta4 (PLCdelta4), termed ALT I and II, that contain an additional 32 and 14 amino acids in their respective sequences in the linker region between the catalytic X and Y domains (Lee, S. B., and Rhee, S. G. (1996) J. Biol. Chem. 271, 25-31). We report here the isolation and characterization of a novel alternative splicing isoform of PLCdelta4, termed ALT III, as a negative regulator of PLC. In ALT III, alternative splicing occurred in the catalytic X domain, i.e. 63 amino acids (residues 424-486) containing the C-terminal of the X domain and linker region were substituted for 32 amino acids corresponding to the insert sequence of ALT I. Although the expression level of ALT III was found to be much lower in most tissues and cells compared with that of PLCdelta4, it was significantly higher in some neural cells, such as NIE-115 cells and p19 cells differentiated to neural cells by retinoic acid. Interestingly, recombinant ALT III protein did not retain enzymatic activity, and the activity of PLCdelta4 overexpressed in COS7 cells was markedly decreased by the co-expression of ALT III but not by ALT I or II. Moreover, N-terminal pleckstrin homology domain (PH domain) of ALT III alone could inhibit the increase of inositol-1,4, 5-trisphosphate levels in PLCdelta4-overexpressing NIH3T3 cells, whereas a PH domain deletion mutant could not, indicating that the PH domain is necessary and sufficient for its inhibitory effect. The ALT III PH domain specifically bound to phosphatidylinositol (PtdIns)-4,5-P2 and PtdIns-3,4,5-P3 but not PtdIns, PtdIns-4-P, or inositol phosphates, and the mutant R36G, which retained only weak affinity for PtdIns-4,5-P2, could not inhibit the activity of PLCdelta4. These results indicate that PtdIns-4,5-P2 binding to PH domain is essential for the inhibitory effect of ALT III. ALT III also inhibited PLCdelta1 activity and partially suppressed PLCgamma1 activity, but not PLCbeta1 in vitro; it did inhibit all types of isozymes tested in vivo. Taken together, our results indicate that ALT III is a negative regulator of PLC that is most effective against the PLC delta-type isozymes, and its PH domain is essential for its function.     

Depression and mental control: The resurgence of unwanted negative thoughts.

In three experiments we examined depressed individuals' mental control abilities and strategies. Experiment 1 revealed that although depressed college students were initially successful in suppressing negative material, they eventually experienced a resurgence of unwanted negative thoughts. Analysis of subjects' stream-of-consciousness reported indicated that this resurgence was associated with the use of negative thoughts as distracters from the unwanted item. In Experiment 2 depressed subjects acknowledged that positive distracters were more effective than negative ones in suppressing negative thoughts. This acknowledgment suggests that depressed subjects in Experiment 1 did not deliberately focus on negative distracters but that depressed subjects' use of positive distracters could be increased somewhat when we provided such distracters and made them easily accessible. Taken together, the findings suggest that depression involves an enhanced accessibility of interconnected negative thoughts that can undermine mental control efforts. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A negative feedback mechanism revealed by functional analysis of the alternative isoforms of the Drosophila splicing regulator transformer-2

The Drosophila sex determination gene transformer-2 (tra-2) is a splicing regulator that affects the sex-specific processing of several distinct pre-mRNAs. While the tra-2 gene itself is known to produce alternative mRNAs that together encode three different TRA-2 protein isoforms, the respective roles of these isoforms in affecting individual pre-mRNA targets has remained unclear. We have generated transgenic fly strains with mutations affecting specific TRA-2 isoforms to investigate their individual roles in regulating the alternative processing of doublesex, exuperantia and tra-2 pre-mRNA. Our results indicate that in somatic tissues two different isoforms function redundantly to direct female differentiation and female-specific doublesex pre-mRNA splicing. In the male germline, where tra-2 has an essential role in spermatogenesis, a single isoform was found to uniquely perform all necessary functions. This isoform appears to regulate its own synthesis during spermatogenesis through a negative feedback mechanism involving intron retention.     

An investigation of the implicit control of the processing of negative pictures.

The implicit control of emotion processing was investigated by varying encoding instructions for both negative and neutral pictures while measuring psychophysiological responses. Participants made comparative judgments about consecutive pictures for blocks of neutral or negative content. The highly specified judgment task was designed to minimize variance in the implementation of implicit control of processing. Affective modulation of startle amplitude was significantly reduced during judgments involving nonnegative content (how "planned" an image was compared to its predecessor), compared to those that involved negative content (how "frightening" an image was compared to its predecessor), indicating successful implicit control of processing. The more attenuated affect modulation was, the less anxious individuals became during the task, suggesting that the implicit control of emotion processing is significantly associated with emotional experience. These data provide convergent evidence for a companion neuroimaging study because of the similar neural substrates thought to underlie affective modulation of startle. This supports the view that higher-level top-down pathways modulate activation of the amygdala. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

浅谈铜管企业谐波治理

针对铜管生产设备产生的谐波的原因、特点及危害,介绍了通过无源滤波与有源滤波相结合的方法治理谐波.该方法利用了无源滤波与自主研发的有源滤波装置各自优点弥补相互间的不足,通过实践证明可以达到良好的谐波治理效果.     

Characterization of multiple regions involved in replication and mobilization of plasmid pNZ4000 coding for exopolysaccharide production in Lactococcus lactis

We characterized the regions involved in replication and mobilization of the 40-kb plasmid pNZ4000, encoding exopolysaccharide (EPS) production in Lactococcus lactis NIZO B40. The plasmid contains four highly conserved replication regions with homologous rep genes (repB1, repB2, repB3, and repB4) that belong to the lactococcal theta replicon family. Subcloning of each replicon individually showed that all are functional and compatible in L. lactis. Plasmid pNZ4000 and genetically labeled derivatives could be transferred to different L. lactis strains by conjugation, and pNZ4000 was shown to be a mobilization plasmid. Two regions involved in mobilization were identified near two of the replicons; both included an oriT sequence rich in inverted repeats. Conjugative mobilization of the nonmobilizable plasmid pNZ124 was promoted by either one of these oriT sequences, demonstrating their functionality. One oriT sequence was followed by a mobA gene, coding for a trans-acting protein, which increased the frequency of conjugative transfer 100-fold. The predicted MobA protein and the oriT sequences show protein and nucleotide similarity, respectively, with the relaxase and with the inverted repeat and nic site of the oriT from the Escherichia coli plasmid R64. The presence on pNZ4000 of four functional replicons, two oriT sequences, and several insertion sequence-like elements strongly suggests that this EPS plasmid is a naturally occurring cointegrate.     

Structure, function, and expression of SEL-1, a negative regulator of LIN-12 and GLP-1 in C. elegans

Previous work indicated that sel-1 functions as a negative regulator of lin-12 activity, and predicted that SEL-1 is a secreted or membrane associated protein. In this study, we describe cell ablation experiments that suggest sel-1 mutations elevate lin-12 activity cell autonomously. We also use transgenic approaches to demonstrate that the predicted signal sequence of SEL-1 can direct secretion and is important for function, while a C-terminal hydrophobic region is not required for SEL-1 function. In addition, by analyzing SEL-1 localization using specific antisera we find that SEL-1 is localized intracellularly, with a punctate staining pattern suggestive of membrane bound vesicles. We incorporate these observations, and new information about a related yeast gene, into a proposal for a possible mechanism for SEL-1 function in LIN-12 turnover.