Determination of volatile metabolites originating from mould growth on wall paper and synthetic media

Microbial volatile organic compounds (MVOCs) emitted from the mould species Penicillium expansum, P. chrysogenum, Aspergillus versicolor, A. fumigatus, A. niger and Cladosporium cladosporoides were analyzed by means of solid phase microextraction (SPME) and GCMS. The mould species were cultivated on the synthetic agar dichloran chloramphenicol (DG 18) and on wet wall paper. The production of MVOCs was monitored over several weeks to detect changes in the emission rates between the initial stage and later periods of growth. The cultivation on the synthetic agar resulted in MVOC patterns with a wide variety of signals. In contrast, the growth on wet wall paper led to changed MVOC patterns with less signals. The emission rates were drastically reduced. Components emitted by all six fungi species on wall paper were 2-pentanol and 2-pentanone. 1-Octen-3-ol was emitted by five fungi species. 2-Pentanol was only detected in considerable amounts during the first days of growth whereas 1-octen-3-ol had a more constant emission rate over the whole period of growth. On the basis of our studies some MVOCs could be proposed as specific for single fungi on wall paper, e.g. 1,3-dimethoxybenzene for A. versicolor and 2,4-pentandione for A. fumigatus.     

Use of standardized brief geriatric evaluation compared with routine care in general practice for preventing functional decline: a pragmatic cluster-randomized trial

Background:Although assessment of geriatric syndromes is increasingly encouraged in older adults, little evidence exists to support its systematic use by general practitioners (GPs). The aim of this study was to determine whether a systematic geriatric evaluation performed by GPs can prevent functional decline.Methods:We conducted a controlled, open-label, pragmatic cluster-randomized trial in 42 general practices in Switzerland. Participating GPs were expected to enrol an average of 10 community-dwelling adults (aged ≥ 75 yr) who understood French, and had visited their GP at least twice in the previous year. The intervention consisted of yearly assessment by the GP of 8 geriatric syndromes with an associated tailored management plan according to assessment results, compared with routine care. Our primary outcomes were the proportion of patients who lost at least 1 instrumental activity of daily living (ADL) and the proportion who lost at least 1 basic ADL, over 2 years. Our secondary outcomes were quality-of-life scores, measured using the older adult module of the World Health Organization Quality of Life Instrument, and health care use.Results:Forty-two GPs recruited 429 participants (63% women) with a mean age of 82.5 years (standard deviation 4.8 yr) at time of recruitment. Of these, we randomly assigned 217 participants to the intervention and 212 to the control arm. The proportion of patients who lost at least 1 instrumental ADL in the intervention and control arms during the course of the study was 43.6% and 47.6%, respectively (risk difference −4.0%, 95% confidence interval [CI] −14.9% to 6.7%, p = 0.5). The proportion of patients who lost at least 1 basic ADL was 12.4% in the intervention arm and 16.9% in the control arm (risk difference −5.1%, 95% CI −14.3% to 4.1%, p = 0.3).Interpretation:A yearly geriatric evaluation with an associated management plan, conducted systematically in GP practices, does not significantly lessen functional decline among community-dwelling, older adult patients, compared with routine care.Trial registration:ClinicalTrials.gov, {"type":"clinical-trial","attrs":{"text":"NCT02618291","term_id":"NCT02618291"}}NCT02618291.

The World Health Organization has defined healthy aging as the process of developing and maintaining functional ability that enables well-being in older age.¹ Functional ability is often measured by an individual’s ability to perform activities of daily living (ADLs) without assistance. Geriatric syndromes, corresponding to multifactorial, chronic conditions, can impair physical and mental capacities,^2–4 and are directly associated with functional decline.⁵ If recognized early, adapted preventive measures and management strategies can be started to limit functional decline.^6–8 Interventions that have been shown to delay functional decline include comprehensive geriatric assessment, regular home visits and physical therapy.^6,8,9 Comprehensive geriatric assessment consists of a “multidisciplinary diagnostic and treatment process that identifies medical, psychosocial, and functional capabilities of older adults to develop a coordinated plan to maximize overall health with ageing.”¹⁰ These assessments are usually performed by specialized geriatric teams for patients who have already been identified as frail or in the context of rehabilitation. However, most older patients see only their general practitioner (GP) and are not provided a comprehensive geriatric assessment, considering that this is a lengthy process that is often beyond the scope of a usual primary care consultation. A recent systematic review of comprehensive geriatric assessment in primary care found only 4 studies conducted in this setting,¹¹ showing mixed effects on clinical outcomes. Only 1 study assessed functional ability, and it showed no impact in this context.¹²In primary care, it may be more beneficial to use shorter screening tools.^13–19 Previous studies using shorter tools adapted for primary care have failed to show a difference for patients compared with routine care.^17,18 These interventions usually targeted patients who were already identified as frail or with a predefined number of problems.^17,18,20In contrast, our Active Geriatric Evaluation (AGE) tool targets all patients aged 75 and older. This clinical tool can be easily integrated to clinical encounters in GP practices, without the need for additional organizational changes. For this study, we aimed to determine whether the AGE tool, specifically designed for GPs and consisting of a brief assessment of the most relevant geriatric syndromes combined with management plans, could slow functional decline in older patients.     

Microbial production host selection for converting second-generation feedstocks into bioproducts

Although many secondary metabolites with diverse biological activities have been isolated from myxobacteria, most strains of these biotechnologically important gliding prokaryotes remain difficult to handle genetically. In this study we describe the new fast growing myxobacterial thermophilic isolate GT-2 as a heterologous host for the expression of natural product biosynthetic pathways isolated from other myxobacteria. According to the results of sequence analysis of the 16S rDNA, this moderately thermophilic isolate is closely related to Corallococcus macrosporus and was therefore named C. macrosporus GT-2. Fast growth of moderately thermophilic strains results in shorter fermentation and generation times, aspects which are of significant interest for molecular biological work as well as production of secondary metabolites. Development of a genetic manipulation system allowed the introduction of the complete myxochromide biosynthetic gene cluster, located on a transposable fragment, into the chromosome of GT-2. Genetic engineering of the biosynthetic gene cluster by promoter exchange leads to much higher production of myxochromides in the heterologous host C. macrosporus GT-2 in comparison to the original producer Stigmatella aurantiaca and to the previously described heterologous host Pseudomonas putida (600 mg/L versus 8 mg/L and 40 mg/L, respectively).     

Synthesis of dihydroxanthone derivatives and evaluation of their inhibitory activity against acetylcholinesterase: unique structural analogs of tacrine based on the BCD-ring of arisugacin

A general approach to synthesis of dihydroxanthone derivatives is described here. In vitro evaluation of these dihydroxanthones demonstrated that some derivatives possess moderate anti-cholinesterase activities and better selectivities than tacrine for acetylcholinesterase over butyrylcholinesterase. Structural effects on anti-cholinesterase activities were also examined, and docking experiments were carried out to provide preliminary understandings of these experimental observations.     

Human TPST1 transmembrane domain triggers enzyme dimerisation and localisation to the Golgi compartment

TPST1 is a human tyrosylprotein sulfotransferase that uses 3'phosphoadenosine-5'phosphosulfate (PAPS) to transfer the sulfate moiety to proteins predominantly designated for secretion. To achieve a general understanding of the cellular role of human tyrosine-directed sulfotransferases, we investigated targeting, structure and posttranslational modification of TPST1. Golgi localisation of the enzyme in COS-7 and HeLa cells was visualised by fluorescence imaging techniques. PNGase treatment and mutational studies determined that TPST1 bears N-linked glycosyl residues exclusively at position Asn60 and Asn262. By alanine mutation of these asparagine residues, we could determine that the N-linked oligosaccharides do not have an influence on Golgi retention of TPST1. In concert with N and C-terminal flanking residues, the transmembrane domain of TPST1 was determined to act in targeting and retention of the enzyme to the trans-Golgi compartment. This domain exhibits a pronounced secondary structure in a lipid environment. Further in vivo FRET studies using the transmembrane domain suggest that the human tyrosylprotein sulfotransferase may be functional as homodimer/oligomer in the trans-Golgi compartment.     

A flow cytometric assay to monitor antimicrobial activity of defensins and cationic tissue extracts

To determine the antibacterial activity of defensins and other antimicrobial peptides in biopsy extracts, we evaluated a flow cytometric method with the membrane potential sensitive dye bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)]. This assay enables us to discriminate intact non-fluorescent and depolarized fluorescent bacteria after exposure to antimicrobial peptides by measurement at the direct target, the cytoplasmic membrane and the membrane potential. The feasibility of the flow cytometric assay was evaluated with recombinant human beta-defensin 3 (HBD-3) against 25 bacterial strains representing 12 species. HBD-3 showed a broad-spectrum dose dependent activity and the minimal dose to cause depolarization ranged from 1.25 to >15 microg/ml HBD-3, depending on the species tested. The antibacterial effect was diminished with sodium chloride or dithiothreitol and could be abrogated with a HBD-3 antibody. Additionally, isolated cationic extracts from human intestinal biopsies showed a strong bactericidal effect against Escherichia coli K12, E. coli ATCC 25922 and Staphylococcus aureus ATCC 25923, which was diminished towards E. coli at 150 mM NaCl, whereas the activity towards S. aureus ATCC 25923 remained unaffected at physiological salt concentrations. DTT blocked the bactericidal effect of biopsy extracts completely.     

Rational drug design via intrinsically disordered protein

Despite substantial increases in research funding by the pharmaceutical industry, drug discovery rates seem to have reached a plateau or perhaps are even declining, suggesting the need for new strategies. Protein-protein interactions have long been thought to provide interesting drug discovery targets, but the development of small molecules that modulate such interactions has so far achieved a low success rate. In contrast to this historic trend, a few recent successes raise hopes for routinely identifying druggable protein-protein interactions. In this Opinion article, we point out the importance of coupled binding and folding for protein-protein signalling interactions generally, and from this and associated observations, we develop a new strategy for identifying protein-protein interactions that would be particularly promising targets for modulation by small molecules. This novel strategy, based on intrinsically disordered protein, has the potential to increase significantly the discovery rate for new molecule entities.     

Phylogeography of post-Pleistocene population expansion in a fungus-gardening ant and its microbial mutualists

Although historical biogeographical forces, such as climate-driven range shifts, greatly influence the present-day population genetic structure of animals and plants, the extent to which they affect microbial communities remains largely unknown. We examined the effect of postglacial expansion on the population structure of the northern fungus-gardening ant Trachymyrmex septentrionalis and compared it with that of its two microbial mutualists: a community of lepiotaceous fungal cultivars and associated antibiotic-producing Pseudonocardia bacteria. The ant population genetic structure showed signs of population expansion and subdivision into eastern and western phylogroups that likely originated in the Pleistocene - a pattern shared by many other North American taxa found in the same region. Although dispersal limitation was present in all three symbionts, as suggested by genetic isolation increasing with distance, the host's east-west subdivision of population genetic structure was absent from the microbial mutualist populations. While neither the cultivar nor the Pseudonocardia genetic structure was correlated with that of the ants, they were significantly correlated with each other. These results show that biogeographical forces may act differently on macro- and microscopic organisms, even in the extreme case where microbial mutualists are vertically transmitted from generation to generation and share the same joint ecological niche. It may be that historical climate change played a larger role in determining the population structure of the ant hosts, whereas present-day environmental forces, such as pathogen pressure, determine the structure of associated microbial populations.     

Influence of sedentary versus physically active conditions on regulation of plasma renin activity and vasopressin

Physical inactivity is an independent risk factor for cardiovascular disease. Sedentary animals compared to physically active controls exhibit enhanced sympathoexcitatory responses, including arterial baroreflex-mediated sympathoexcitation. Hypotension-induced sympathoexcitation is also associated with the release of vasoactive hormones. We hypothesized that sedentary conditions may enhance release of the vasoactive hormones AVP and ANG II. To test this hypothesis, the humoral response to hypotension was examined in conscious rats after 9-12 wk of sedentary conditions or "normally active" conditions. Normally active conditions were produced by allowing rats access to running wheels in their home cages. Running distance peaked after 4 wk (4.5 +/- 0.7 km/day), and the total distance run after 9 wk was 174 +/- 23 km (n = 25). Similar levels of hypotension were induced in conscious sedentary or physically active animals with the arterial vasodilator, diazoxide (25 mg/kg iv). Control experiments used a saline injection of equivalent volume. Plasma samples were collected and assayed for plasma AVP concentration and plasma renin activity (PRA). Sedentary conditions significantly enhanced resting and hypotension-induced PRA relative to normal physical activity. In contrast, resting and hypotension-induced AVP levels were not statistically different between groups. These data suggest that baroreflex-mediated activation of the renin-angiotensin system, but not AVP secretion, is enhanced by sedentary conditions. We speculate that augmented activation of the renin-angiotensin system may be related to enhanced sympathetic outflow observed in sedentary animals and may contribute to increased risk of cardiovascular disease in the sedentary population.     

Sleep deprivation can inhibit adult hippocampal neurogenesis independent of adrenal stress hormones

Sleep deprivation (SD) can suppress cell proliferation in the hippocampal dentate gyrus of adult male rodents, suggesting that sleep may contribute to hippocampal functions by promoting neurogenesis. However, suppression of cell proliferation in rats by the platform-over-water SD method has been attributed to elevated corticosterone (Cort), a potent inhibitor of cell proliferation and nonspecific correlate of this procedure. We report here results that do not support this conclusion. Intact and adrenalectomized (ADX) male rats were subjected to a 96-h SD using multiple- and single-platform methods. New cells were identified by immunoreactivity for 5-bromo-2'-deoxyuridine (BrdU) or Ki67 and new neurons by immunoreactivity for BrdU and doublecortin. EEG recordings confirmed a 95% deprivation of rapid eye movement (REM) sleep and a 40% decrease of non-REM sleep. Cell proliferation in the dentate gyrus was suppressed by up to 50% in sleep-deprived rats relative to apparatus control or home cage control rats. This effect was also observed in ADX rats receiving continuous low-dose Cort replacement via subcutaneous minipumps but not in ADX rats receiving Cort replacement via drinking water. In these latter rats, Cort intake via water was reduced by 60% during SD; upregulation of cell proliferation by reduced Cort intake may obscure inhibitory effects of sleep loss on cell proliferation. SD had no effect on the percentage of new cells expressing a neuronal phenotype. These results demonstrate that the Cort replacement method is critical for detecting an effect of SD on cell proliferation and support a significant role for sleep in adult neurogenesis.