Temperature range for formic hydrogenlyase induction and activity in psychrophilic and mesophilic bacteria

The temperature range for induction of formic hydrogenlyase in cell suspensions of psychrophilic strain 82 was 0 C to 20 C compared to 15 C to 45 C for mesophilicEscherichia coli and 15 C to 40 C for mesophilicAerobacter aerogenes. The respective temperatures for maximum enzyme activity were 30 C, 45 C and 40 C, and for formation of the maximum amount of enzyme 15 C, 35 C and 30 C. The temperatures for all three enzyme functions, therefore, were considerably lower for the psychrophile than for the mesophiles.This research has been supported by a grant from the National Science Foundation.     

Exposure to isoprene promotes flowering in plants

In separate experiments, plants of barley, oil-seed rape andArabidopsis were grown in controlled environment fumigationchambers and were subsequently exposed either to isoprene gas(50–150 parts per billion by volume (ppbv)) or to cleanair only. In every experiment exposure to isoprene significantlyaccelerated the onset of flowering. The physiological and ecologicalsignificance of these findings are discussed. Key words: Flowering, isoprene, hydrocarbon     

The growth hormone response to repeated bouts of sprint exercise with and without suppression of lipolysis in men.

A single 30-s sprint is a potent physiological stimulus for growth hormone (GH) release. However, repeated bouts of sprinting attenuate the GH response, possibly due to negative feedback via elevated systemic free fatty acids (FFA). The aim of the study was to use nicotinic acid (NA) to suppress lipolysis to investigate whether serum FFA can modulate the GH response to exercise. Seven nonobese, healthy men performed two trials, consisting of two maximal 30-s cycle ergometer sprints separated by 4 h of recovery. In one trial (NA), participants ingested NA (1 g 60 min before, and 0.5 g 60 and 180 min after sprint 1); the other was a control (Con) trial. Serum FFA was not significantly different between trials before sprint 1 but was significantly lower in the NA trial immediately before sprint 2 [NA vs. Con: mean (SD); 0.08 (0.05) vs. 0.75 (0.34) mmol/l, P < 0.05]. Peak and integrated GH were significantly greater following sprint 2 compared with sprint 1 in the NA trial [peak GH: 23.3 (7.0) vs. 7.7 (11.9) microg/l, P < 0.05; integrated GH: 1,076 (350) vs. 316 (527) microg.l(-1).60 min(-1), P < 0.05] and compared with sprint 2 in the Con trial [peak GH: 23.3 (7.0) vs. 5.2 (2.3) microg/l, P < 0.05; integrated GH: 1,076 (350) vs. 206 (118) microg.l(-1).60 min(-1), P < 0.05]. In conclusion, suppressing lipolysis resulted in a significantly greater GH response to the second of two sprints, suggesting a potential role for serum FFA in negative feedback control of the GH response to repeated exercise.     

Membrane invagination in Rhodobacter sphaeroides is initiated at curved regions of the cytoplasmic membrane,then forms both budded and fully detached spherical vesicles

The purple phototrophic bacteria synthesize an extensive system of intracytoplasmic membranes (ICM) in order to increase the surface area for absorbing and utilizing solar energy. Rhodobacter sphaeroides cells contain curved membrane invaginations. In order to study the biogenesis of ICM in this bacterium mature (ICM) and precursor (upper pigmented band – UPB) membranes were purified and compared at the single membrane level using electron, atomic force and fluorescence microscopy, revealing fundamental differences in their morphology, protein organization and function. Cryo‐electron tomography demonstrates the complexity of the ICM of Rba. sphaeroides. Some ICM vesicles have no connection with other structures, others are found nearer to the cytoplasmic membrane (CM), often forming interconnected structures that retain a connection to the CM, and possibly having access to the periplasmic space. Near‐spherical single invaginations are also observed, still attached to the CM by a ‘neck’. Small indents of the CM are also seen, which are proposed to give rise to the UPB precursor membranes upon cell disruption. ‘Free‐living’ ICM vesicles, which possess all the machinery for converting light energy into ATP, can be regarded as bacterial membrane organelles.     

Multimorbidity combinations,costs of hospital care and potentially preventable emergency admissions in England: A cohort study

BackgroundPatients with multimorbidities have the greatest healthcare needs and generate the highest expenditure in the health system. There is an increasing focus on identifying specific disease combinations for addressing poor outcomes. Existing research has identified a small number of prevalent “clusters” in the general population, but the limited number examined might oversimplify the problem and these may not be the ones associated with important outcomes. Combinations with the highest (potentially preventable) secondary care costs may reveal priority targets for intervention or prevention. We aimed to examine the potential of defining multimorbidity clusters for impacting secondary care costs.Methods and findingsWe used national, Hospital Episode Statistics, data from all hospital admissions in England from 2017/2018 (cohort of over 8 million patients) and defined multimorbidity based on ICD-10 codes for 28 chronic conditions (we backfilled conditions from 2009/2010 to address potential undercoding). We identified the combinations of multimorbidity which contributed to the highest total current and previous 5-year costs of secondary care and costs of potentially preventable emergency hospital admissions in aggregate and per patient. We examined the distribution of costs across unique disease combinations to test the potential of the cluster approach for targeting interventions at high costs. We then estimated the overlap between the unique combinations to test potential of the cluster approach for targeting prevention of accumulated disease. We examined variability in the ranks and distributions across age (over/under 65) and deprivation (area level, deciles) subgroups and sensitivity to considering a smaller number of diseases.There were 8,440,133 unique patients in our sample, over 4 million (53.1%) were female, and over 3 million (37.7%) were aged over 65 years. No clear “high cost” combinations of multimorbidity emerged as possible targets for intervention. Over 2 million (31.6%) patients had 63,124 unique combinations of multimorbidity, each contributing a small fraction (maximum 3.2%) to current-year or 5-year secondary care costs. Highest total cost combinations tended to have fewer conditions (dyads/triads, most including hypertension) affecting a relatively large population. This contrasted with the combinations that generated the highest cost for individual patients, which were complex sets of many (6+) conditions affecting fewer persons. However, all combinations containing chronic kidney disease and hypertension, or diabetes and hypertension, made up a significant proportion of total secondary care costs, and all combinations containing chronic heart failure, chronic kidney disease, and hypertension had the highest proportion of preventable emergency admission costs, which might offer priority targets for prevention of disease accumulation. The results varied little between age and deprivation subgroups and sensitivity analyses.Key limitations include availability of data only from hospitals and reliance on hospital coding of health conditions.ConclusionsOur findings indicate that there are no clear multimorbidity combinations for a cluster-targeted intervention approach to reduce secondary care costs. The role of risk-stratification and focus on individual high-cost patients with interventions is particularly questionable for this aim. However, if aetiology is favourable for preventing further disease, the cluster approach might be useful for targeting disease prevention efforts with potential for cost-savings in secondary care.

Jonathan Stokes and co-workers explore patterns of multimorbidity and implications for the organization and costs of care.     

Formation of rough and smooth strains ofSphaerotilus discophorus

Sphaerotilus discophorus forms characteristic filamentous dark brown colonies on dilute organic media containing managanous salts. Spontaneously or by induction the organism may produce an entirely different kind of colony, the S type which is smooth, glistening, hemispherical with a regular edge, and colorless. The latter resembles, therefore, colonies of common bacteria. The S colony may be a temporary modification imposed by nutritional conditions or a mutation.Temporary S-colony modifications occurred when a 0.5% peptone, mineral salts agar was enriched with 0.2 to 1.0% glucose, galactose, mannitol, sucrose or salicin but not with raffinose, glycerol or Na lactate. Two per cent peptone and 0.5% tryptose also stimulated temporary S-colony formation. However, the dark brown pigmentation, i.e. MnO₂ deposition, persisted in contrast to its marked repression by sugars. Phytone and tryptone are partially effective in S-colony formation and proteose-peptone is ineffective.Mutations of R to S strains were obtained by ageing broth cultures of R strains. The mutant S strains were identical to the parent R strains in nutritional and physiological properties but differed apparently in that they did not form sheaths or oxidize manganous salts.