The extracellular matrix protein TasA is a developmental cue that maintains a motile subpopulation within Bacillus subtilis biofilms

In nature, bacteria form biofilms-differentiated multicellular communities attached to surfaces. Within these generally sessile biofilms, a subset of cells continues to express motility genes. We found that this subpopulation enabled Bacillus subtilis biofilms to expand on high-friction surfaces. The extracellular matrix (ECM) protein TasA was required for the expression of flagellar genes. In addition to its structural role as an adhesive fiber for cell attachment, TasA acted as a developmental signal stimulating a subset of biofilm cells to revert to a motile phenotype. Transcriptomic analysis revealed that TasA stimulated the expression of a specific subset of genes whose products promote motility and repress ECM production. Spontaneous suppressor mutations that restored motility in the absence of TasA revealed that activation of the biofilm-motility switch by the two-component system CssR/CssS antagonized the TasA-mediated reversion to motility in biofilm cells. Our results suggest that although mostly sessile, biofilms retain a degree of motility by actively maintaining a motile subpopulation.

Incidence of injuries and factors related to injuries in combat soldiers

Introduction

Musculoskeletal injuries to the lower extremities are major factors contributing to drop out from military tasks. The aim of the present study was to determine the incidence of musculoskeletal injuries and the parameters that differentiate between the soldiers who incurred these injuries and those who did not along 14 weeks of an infantry commanders course.

Methods

One-hundred and sixty-eight participants were recruited from an infantry commanders course. The soldiers were tested before (pre), in the middle (middle) and at the end (last) of the course for anthropometric measurements, proprioceptive ability and dynamic postural balance (DPB), and filled out an ankle stability questionnaire (Cumberland Ankle Instability Tool (CAIT). A physiotherapist followed and recorded all musculoskeletal injuries incurred by the participants during the course.

Results

Fifty-eight participants out of the 168 (34.5%) reported some pain/injury. Time effects were found for body mass index, DPB asymmetry, DPB in posterior-medial (P-M) direction and proprioception ability. Injury effects were found for DPB asymmetry, DPB in P-M direction, CAIT and proprioception ability. An interaction was found for proprioception ability. The Cox regression showed that the variables that are mostly effecting injuries were pretesting proprioception ability, DPB asymmetry and CAIT.

Conclusions

More than one out of three participants incurred musculoskeletal injuries, with deficits in proprioception ability, DPB and ankle stability in pretesting as major factors contributing to injuries. Further studies should look at the effect of specific exercises such as proprioception, DPB and ankle stability exercises for prevention and treatment of musculoskeletal injuries among combat soldiers.

CHANGES IN BINOCULAR PUPILLOMETRY IN ATHLETES AFTER HIGH EXERCISE STRESS

Aim. The article deals with studying the changes in binocular pupillometry to establish vegetative activity in athletes after high exercise stress. Materials and methods. 25 male athletes aged 19–34 years with no health limitations participated in the study. We estimated a set of the commonly accepted parameters of pupillometry (pupil diameter, pupil reaction initiation time, pupil constriction diameter, pupil constriction velocity) by measuring pupil reaction to a light stimulus with the help of a non-contact pupilometer (KVAZAR, Moscow). The examination was conducted prior to physical stress and 5, 15, and 30 minutes after. Intertrack-750 treadmill (SchillerAG, Switzerland) was used for testing. Results. The results obtained in a pupillometric study prove that there is a predominance of the sympathetic component in athletes at maximal load accompanied by emotional stress. After physical stress accompanied by fatigue and nervous system exhaustion, there is a pronounced predominance of the parasympathetic component. Conclusion. The data obtained prove that binocular pupillometry can be effectively used in sports medicine to estimate vegetative tone and regulatory mechanisms in athletes.

Novel antibiofilm chemotherapies target nitrogen from glutamate and glutamine

Bacteria in nature often reside in differentiated communities termed biofilms, which are an active interphase between uni-cellular and multicellular life states for bacteria. Here we demonstrate that the development of B. subtilis biofilms is dependent on the use of glutamine or glutamate as a nitrogen source. We show a differential metabolic requirement within the biofilm; while glutamine is necessary for the dividing cells at the edges, the inner cell mass utilizes lactic acid. Our results indicate that biofilm cells preserve a short-term memory of glutamate metabolism. Finally, we establish that drugs that target glutamine and glutamate utilization restrict biofilm development. Overall, our work reveals a spatial regulation of nitrogen and carbon metabolism within the biofilm, which contributes to the fitness of bacterial complex communities. This acquired metabolic division of labor within biofilm can serve as a target for novel anti-biofilm chemotherapies

Collective Vortex-Like Movement of Bacillus subtilis Facilitates the Generation of Floating Biofilms

Bacteria in nature are usually found in complex multicellular structures, called biofilms. One common form of a biofilm is pellicle—a floating mat of bacteria formed in the water-air interphase. So far, our knowledge on the basic mechanisms underlying the formation of biofilms at air-liquid interfaces is not complete. In particular, the co-occurrence of motile cells and extracellular matrix producers has not been studied. In addition, the potential involvement of chemical communication in pellicle formation remained largely undefined. Our results indicate that vortex-like collective motility by aggregates of motile cells and EPS producers accelerate the formation of floating biofilms. Successful aggregation and migration to the water-air interphase depend on the chemical communication signal autoinducer 2 (AI-2). This ability of bacteria to form a biofilm in a preferable niche ahead of their potential rivals would provide a fitness advantage in the context of inter-species competition.

A balance and proprioception intervention programme to enhance combat performance in military personnel

BACKGROUND

Optimal functioning of the lower extremities under repeated movements on unstable surfaces is essential for military effectiveness. Intervention training to promote proprioceptive ability should be considered in order to limit the risk for musculoskeletal injuries. The aim of this study was to assess the effect of a proprioceptive intervention programme on static and dynamic postural balance among Israel Defense Forces combat soldiers.

METHODS

Twenty-seven male soldiers, aged 18-20 years, from a physical fitness instructor's course, were randomly divided into two groups matched by age and army unit. The intervention group (INT) underwent 4 weeks of proprioceptive exercises for 10 min daily; the control group underwent 4 weeks of upper body stretching exercises for 10 min daily. All participants were tested pre and postintervention for both static and dynamic postural balance.

RESULTS

Significant interaction (condition*pre-post-test*group) was found for static postural balance, indicating that for the INT group, in condition 3 (on an unstable surface-BOSU), the post-test result was significantly better compared with the pretest result (p<0.05). Following intervention, the INT group showed significant correlations between static postural stability in condition 2 (eyes closed) and the dynamic postural stability (length of time walked on the beam following fatigue) (r ranged from 0.647 to 0.822; p<0.05).

CONCLUSIONS

The proprioceptive intervention programme for combat soldiers improved static postural balance on unstable surfaces, and improved the correlation between static postural balance in the eyes closed condition and dynamic postural balance following fatigue. Further longitudinal studies are needed to verify the relationship between proprioception programmes, additional weight bearing and the reduction of subsequent injuries in combat soldiers.

Toxin-Antitoxin systems eliminate defective cells and preserve symmetry in Bacillus subtilis biofilms

Toxin-antitoxin modules are gene pairs encoding a toxin and its antitoxin, and are found on the chromosomes of many bacteria, including pathogens. Here, we characterize the specific contribution of the TxpA and YqcG toxins in elimination of defective cells from developing Bacillus subtilis biofilms. On nutrient limitation, defective cells accumulated in the biofilm breaking its symmetry. Deletion of the toxins resulted in accumulation of morphologically abnormal cells, and interfered with the proper development of the multicellular community. Dual physiological responses are of significance for TxpA and YqcG activation: nitrogen deprivation enhances the transcription of both TxpA and YqcG toxins, and simultaneously sensitizes the biofilm cells to their activity. Furthermore, we demonstrate that while both toxins when overexpressed affect the morphology of the developing biofilm, the toxin TxpA can act to lyse and dissolve pre-established B. subtilis biofilms.

A gene locus for targeted ectopic gene integration in Zymoseptoria tritici

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We establish the sdi1 of Z. tritici locus for targeted integration of constructs as single copies.

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Integration of constructs conveys carboxin resistance.

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We provide a vector for integration of eGFP-expressing construct into the sdi1 locus.

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Integration into sdi1 locus is not affecting virulence of Z. tritici.

Understanding the cellular organization and biology of fungal pathogens requires accurate methods for genomic integration of mutant alleles or fluorescent fusion-protein constructs. In Zymoseptoria tritici, this can be achieved by integrating of plasmid DNA randomly into the genome of this wheat pathogen. However, untargeted ectopic integration carries the risk of unwanted side effects, such as altered gene expression, due to targeting regulatory elements, or gene disruption following integration into protein-coding regions of the genome. Here, we establish the succinate dehydrogenase (sdi1) locus as a single “soft-landing” site for targeted ectopic integration of genetic constructs by using a carboxin-resistant sdi1^R allele, carrying the point-mutation H267L. We use various green and red fluorescent fusion constructs and show that 97% of all transformants integrate correctly into the sdi1 locus as single copies. We also demonstrate that such integration does not affect the pathogenicity of Z. tritici, and thus the sdi1 locus is a useful tool for virulence analysis in genetically modified Z. tritici strains. Furthermore, we have developed a vector which facilitates yeast recombination cloning and thus allows assembly of multiple overlapping DNA fragments in a single cloning step for high throughput vector and strain generation.

The association between hallux valgus and proximal joint alignment in young female dancers

Very little is known about the relationship between proximal joint alignment and hallux valgus among young dancers. This study sought to determine the extent to which spinal and lower extremity alignments are involved in hallux valgus, and to identify predicting variables for its development in young dancers. A group of 1336 young female dancers aged 8-16 years, and 226 control participants of the same age cohort were screened for the presence of hallux valgus, body physique characteristics, joint range of motion, and anatomical anomalies. Hallux valgus was common in the 2 young female populations studied. Among the dancers, 40.0% had bilateral hallux valgus and 7.3% unilateral. Among the controls, 32.3% had bilateral and 1.8% unilateral hallux valgus (χ2=8.27, df=1, p=0.004). Following logistic regression analysis, age (OR=1.028, 95% CI=0.968-1.091), genu varum (OR=1.514; CI=1.139-2.013) and scoliosis (OR=2.089; CI=1.113-3.921) were found to be significant predicting factors for hallux valgus in the dancer group, whereas in the control group, the predicting factors were age (OR=0.911, 95% CI=0.801-1.036) and ankle plantar flexion range of motion (OR=0.972; CI=0.951-0.992). In conclusion, it was found that spinal deformity, lower extremity alignment, and joint range of motion are strongly related to hallux valgus.

Injuries among talented young dancers: findings from the U.K. Centres for Advanced Training

The aim of the present study was to characterize the injuries of young dancers attending Centres for Advanced Training. 806 dancers, ages 10-18 years responded to surveys regarding their biological profile, dance experience and injury history, and were examined for their anthropometric profile. Of the 806 dancers, 347 reported an injury. Based on 4 age groups, the total hours of practice per week increased significantly with increasing age. Incidence of injuries per 1000 h of dance practice for dancers ages 11-12 were found to be significantly higher compared to the incidence for dancers ages 13-18 (p<0.05). Foot and ankle and other lower extremities were the most common injury location, and muscle injuries were the most common type of injury. Total months in CAT training (OR=1.044, 95% CI=1.014-1.075) and hours per week in creative style practice (OR=1.282, 95% CI=1.068-1.539) were found to be significantly associated with injuries. In conclusion, both young and mature dancers are exposed to extensive risk of injury. The intensity of training (such as number of months and number of hours of training per week) is important factor that should be taken into account in order to decrease future injuries among young dancers.

Nocturnal activation of aurora C in rat pineal gland: its role in the norepinephrine-induced phosphorylation of histone H3 and gene expression

We have shown previously that Ser10 phosphorylation of histone H3 occurs in rat pinealocytes after stimulation with norepinephrine (NE) and that histone modifications such as acetylation appear to play an important role in pineal gene transcription. Here we report the nocturnal phosphorylation of a Ser10 histone H3 kinase, Aurora C, in the rat pineal gland. The time profile of this phosphorylation parallels the increase in the level of phospho-Ser10 histone H3. Studies with cultured pinealocytes indicate that Aurora C phosphorylation is induced by NE and this induction can be blocked by cotreatment with propranolol or KT5720, a protein kinase A inhibitor. Moreover, only treatment with dibutyryl cAMP, but not other kinase activators, mimics the effect of NE on Aurora C phosphorylation. These results indicate that Aurora C is phosphorylated primarily by a beta-adrenergic/protein kinase A-mediated mechanism. Treatment with an Aurora C inhibitor reduces the NE-induced histone H3 phosphorylation and suppresses the NE-stimulated induction of arylalkylamine N-acetyltransferase (AA-NAT), the rhythm-controlling enzyme of melatonin synthesis, and melatonin production. The effects of Aurora C inhibitors on adrenergic-induced genes in rat pinealocytes are gene specific: inhibitory for Aa-nat and inducible cAMP repressor but stimulatory for c-fos. Together our results support a role for the NE-stimulated phosphorylation of Aurora C and the subsequent remodeling of chromatin in NE-stimulated Aa-nat transcription. This phenomenon suggests that activation of this mitotic kinase can be induced by extracellular signals to participate in the transcriptional induction of a subset of genes in the rat pineal gland.

Acetylation of histone H3 and adrenergic-regulated gene transcription in rat pinealocytes

In this study we investigated the effect of histone acetylation on the transcription of adrenergic-induced genes in rat pinealocytes. We found that treatment of pinealocytes with trichostatin A (TSA), a histone deacetylase inhibitor, caused hyperacetylation of histone H3 (H3) Lys14 at nanomolar concentrations. Hyperacetylation of H3 was also observed after treatment with scriptaid, a structurally unrelated histone deacetylase inhibitor. The effects of TSA and scriptaid were inhibitory on the adrenergic induction of arylalkylamine-n-acetyltransferase (aa-nat) mRNA, protein, and enzyme activity, and on melatonin production. TSA at higher concentrations also inhibited the adrenergic induction of mapk phosphatase-1 (mkp-1) and inducible cAMP early repressor mRNAs. In contrast, the effect of TSA on the norepinephrine induction of the c-fos mRNA was stimulatory. Moreover, the effect of TSA on adrenergic-induced gene transcription was dependent on the time of its addition; its effect was only observed during the active phase of transcription. Chromatin immunoprecipitation with antibodies against acetylated Lys14 of H3 showed an increase in DNA recovery of the promoter regions of aa-nat, mkp-1, and c-fos after treatment with TSA. Together, our results demonstrate that histone acetylation differentially influences the transcription of adrenergic-induced genes, an enhancing effect for c-fos but inhibitory for aa-nat, mkp-1, and inducible cAMP early repressor. Moreover, both inhibitory and enhancing effects appear to be mediated through specific modification of promoter-bound histones during gene transcription.

Patella measurements of South African whites as sex assessors

This study uses metrical characteristics of the patella to derive population specific equations for sex determination in South Africa. Six measurements were taken from 120 normal and undamaged left patellae in a sample of known race, equally distributed by sex, obtained from the Raymond A Dart collection of human skeletons. These data were subjected to discriminant analysis. Maximum height and maximum breadth were selected in the stepwise analysis with an average accuracy of 83% in correct sex classification. Four functions were derived from the direct analysis with a range of average accuracy between 77% and 85%. While most individual variables showed high misclassification rates and may not be useful on their own, maximum height and maximum breadth have an average accuracy of 85 and 79%, respectively.

Torpedo acetylcholinesterase is inactivated by thiol reagents

A number of sulphydryl reagents inhibit AChE of Torpedo california with pseudo-first-order kinetics, and inhibition can be retarded by quaternary ligands which bind at either the catalytic or peripheral anionic binding sites. Colorimetric determination with one of the inhibitory sulphydryl agents, 5,5'-dithiobis (2-nitrobenzoic acid), reveals the presence of a single thiol group per catalytic subunit; our data thus suggest that inhibition is achieved by reaction with the single free sulphydryl group of Cys231.

Aged and non-aged pyrenebutyl-containing organophosphoryl conjugates of chymotrypsin. Preparation and comparison by 31P-NMR spectroscopy

Homologous pairs of non-aged and aged pyrene-containing phosphoryl conjugates of chymotrypsin were prepared in order to characterize by NMR and optical spectroscopy putative differences in the conformation of non-aged and aged organophosphoryl conjugates of serine hydrolases. Pyrenebutyl-O-P(O)(OC2H5)F and pyrenebutyl-O-P(O)(OC2H5)Cl were used to obtain the non-aged form pyrenebutyl-O-P(O)(OC2H5)-Cht, whereas pyrenebutyl-O-P(O)Cl2, pyrenebutyl-O-P(O)(p-nitrophenoxy)Cl, and pyrenebutyl-O-P(O)(p-nitrophenoxy)2 were used to produce the aged conjugate pyrenebutyl-O-P(O)(O )-Cht. These ligands bind covalently to the active site of serine hydrolases. The absorption spectra of both the non-aged and aged conjugates fitted approximately a 1:1 stoichiometry of bound organophosphate and enzyme in the non-aged and aged conjugates. Pyrenebutyl-O-P(O)(OC2H5)-Cht could be reactivated by pyridine-3-aldoxime methiodide, whereas no reactivation was observed for the similarly treated pyrenebutyl-O-P(O)(O-)-Cht. The 31P-NMR and reactivation data taken together strongly support the hypothesis that the aged form of the OP-Cht conjugate contains a P--O- bond. These results provide a partial interpretation for the known resistance of the aged conjugates of serine hydrolases to reactivation.

Conformational differences between aged and nonaged pyrenebutyl-containing organophosphoryl conjugates of chymotrypsin as detected by optical spectroscopy

Homologous aged and nonaged fluorescent organophosphorus conjugates of alpha-chymotrypsin (Cht) were used in a comparative spectroscopic study of the conformation of their active sites, employing the pyrene group as the fluorescent probe. Steady-state fluorescence measurements showed that the quantum yield of the pyrene probe which is stoichiometrically attached to the active site is ca. 20% lower in the aged conjugate, pyrenebutyl-O-P(O)(O-)-Cht (PBP-Cht), than in the nonaged conjugate, pyrenebutyl-O-P-(O)(OC2H5)-Cht (PBEP-Cht). Furthermore, fluorescence decay data indicate that quenching is dynamic and is not caused by oxygen. These data, together with collisional quenching data, imply that quenching originates in an internal interaction of the fluorophore with a group within the protein. Thus, interaction of the pyrene moiety with the polypeptide chain is significantly stronger in the aged than in the nonaged conjugate, implying a different orientation of the fluorophore with respect to the protein. Circular dichroism measurements, which reflect the asymmetry of the bound pyrene in the ground state, as well as circularly polarized luminescence studies, which reflect its asymmetry in the excited state, also show that the relative configuration of the pyrene moiety and the polypeptide chain is significantly altered upon aging. Aged conjugates obtained by use of various fluorescenct organophosphates [pyrenebutyl-O-P(O)Cl2, pyrenebutyl-O-P(O)(p-nitrophenoxy)Cl, pyrenebutyl-O-P(O)(p-nitrophenoxy)2] exhibit similar spectroscopic features, thus substantiating the hypothesis that instantaneous aging, by use of pyrenebutyl-O-P(O)Cl2, and dynamic aging, by gradual removal of an aryloxy group, yield a similar product. This finding provides strong support for the formation of a P-O- moiety in the aged conjugates, since the only expected common product of the two processes is PB-O-P(O)(O-)-Cht. Formation of excimers of the pyrene-containing organophosphorylchymotrypsin conjugates at concentrations above 3 X 10(-6) M is also reported.

The evaluation of a consultation-liaison service

The demographics, referral patterns, and diagnoses of a psychiatric consultation-liaison service during a 1-year period are reported. A comparison with data from a similar evaluation of the same service 10 years previously showed stability in most variables. The data suggest that mere availability of a consultation-liaison service does not necessarily lead to increased utilization and highlights the need to forge specific links with other specialties. The use of DSM-III diagnoses in a consultation-liaison service is discussed.

Ionic strength dependent conformational changes of transfer ribonucleic acid studied by circular polarization of phosphorescence

The circularly polarized phosphorescence emitted by the 4-thiouridine base was measured for bulk Escherichia coli tRNA, E. coli tRNA1Val, E. coli tRNAfMet, and E. coli tRNAPhe as a function of ionic strength in the presence of 1 mM Mg2+. The emission anisotropy factor, gem, was found to be dependent on the degree of local stacking in the vicinity of the chromophore. For bulk tRNA and tRNAfMet a marked similarity was observed between the behavior of gem and the translational diffusion coefficient D020,w [Pots, R. O., Wang, C. C., Fritzinger, D. C., Ford, N. C. & Fournier, M. J. (1979) in Cold Spring Harbor Monograph Series (Schimmel, P. R; Söll, D., & Abelson, J. N., Eds.) Part A, p 207, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY]. This was interpreted to mean that a relationship exists between the local stacking around the 4-thiouridine chromophore and the overall general similarity of behavior was observed, each species of tRNA examined exhibited a distinctive dependence of conformation on salt concentration. tRNAPhe was found to be a particular exception in the low-salt region (less than 50 mM). The value of the phosphorescence anisotropy factor was found to be remarkably larger (about 50-fold). Thus minor conformational changes in the tRNA molecule are more readily detected by circular polarization of phosphorescence than by circular dichroism