Low cell surface hydrophobicity is one of the key factors for high butanol tolerance of Lactic acid bacteria

Highly butanol‐tolerant strains have always been attractive because of their potential as microbial hosts for butanol production. However, due to the amphiphilic nature of 1‐butanol as a solvent, the relationship between the cell surface hydrophobicity and butanol resistance remained ambiguous to date. In this work, the quantitatively estimated cell surface hydrophobicity of 74 Lactic acid bacteria strains were juxtaposed to their tolerance to various butanol concentrations. The obtained results revealed that the strains’ hydrophobicity was inversely proportional to their butanol tolerance. All highly butanol‐resistant strains were hydrophilic (cell surface hydrophobicity<1%), whereas the more hydrophobic the strains were, the more sensitive to butanol they were. Furthermore, cultivation at increasing butanol concentrations showed a clear tendency to decrease the level of hydrophobicity in all tested organisms, thus suggesting possible adaptation mechanisms. Purposeful reduction of cell surface hydrophobicity (by removal of S‐layer proteins from the cell envelope) also led to an increase of butanol resistance. Since the results covered 23 different Lactic acid bacteria species of seven genera, it could be concluded that regardless of the species, the lower degree of cells’ hydrophobicity clearly correlates with the higher level of butanol tolerance.     

Preserved postischemic heart function in sucrose-fed type 2 diabetic OLETF rats

Cardiovascular disease is one of the most important causes of morbidity and mortality in diabetes mellitus, but there has been controversy over functional impairment of diabetic hearts and their tolerance to ischemia. We studied ischemic heart function in type 2 diabetic rats with different degrees of hyperglycemia and its relationship with cardiac norepinephrine release. Otsuka Long-Evans Tokushima Fatty rats (OLETF) and age-matched Long-Evans Tokushima Otsuka normal rats (LETO) were used. One group of OLETF rats was given 30% sucrose in drinking water (OLETF-S). Hearts were isolated and perfused in a working heart preparation and subjected to 30 min ischemia followed by 40 min reperfusion at age of 12 months. Hemodynamics and coronary norepinephrine overflow were examined. Fasting plasma glucose in OLETF increased markedly at 12 months and sucrose administration exacerbated hyperglycemia in diabetic rats (LETO 6.6 +/- 0.5, OLETF 8.3 +/- 0.7, OLETF-S 15.0 +/- 1.7 mmol/L, P < 0.01). Basic cardiac output in OLETF was decreased as compared with LETO and OLETF-S (LETO 29.4 +/- 2.5, OLETF 24.0 +/- 2.4, OLETF-S 27.0 +/- 0.9 ml/min/g, P < 0.05) and remained very low after ischemia, while in OLETF-S it was well preserved (OLETF 4.2 +/- 2.1, OLETF-S 13.7 +/- 2.6 ml/min/g, P < 0.01). Correspondently, cardiac norepinephrine released during ischemia and reperfusion was lower in OLETF-S (OLETF 2.3 +/- 1.0, OLETF-S 0.7 +/- 0.1 pmol/ml, P < 0.01). Thus, OLETF hearts were more vulnerable to ischemia but sucrose feeding rendered their hearts resistant to ischemia. Less norepinephrine release may play a role in preventing postischemic functional deterioration in sucrose-fed diabetic hearts.     

Factors Related to Social Support in Neurological and Mental Disorders

Despite the huge body of research on social support, literature has been primarily focused on its beneficial role for both physical and mental health. It is still unclear why people with mental and neurological disorders experience low levels of social support. The main objective of this study was to explore what are the strongest factors related to social support and how do they interact with each other in neuropsychiatric disorders. The study used cross-sectional data from 722 persons suffering from dementia, depression, epilepsy, migraine, multiple sclerosis, Parkinson''s disease, schizophrenia, stroke, and substance use disorders. Multiple linear regressions showed that disability was the strongest factor for social support. Extraversion and agreeableness were significant personality variables, but when the interaction terms between personality traits and disability were included, disability remained the only significant variable. Moreover, level of disability mediated the relationship between personality (extraversion and agreeableness) and level of social support. Moderation analysis revealed that people that had mental disorders experienced lower levels of support when being highly disabled compared to people with neurological disorders. Unlike previous literature, focused on increasing social support as the origin of improving disability, this study suggested that interventions improving day-to-day functioning or maladaptive personality styles might also have an effect on the way people perceive social support. Future longitudinal research, however, is warranted to explore causality.     

Effects of beta endorphin and delta-sleep inducing peptide on resistance to emotional stress

Enzyme immunoassay was used to study the contents of beta-endorphin and delta-sleep inducing peptide (DSIP) in blood and hypothalamus in rats of Wistar and August lines under acute emotional stress. The stress-resistance of the animals was determined by using preliminary behavior tests. The rats were divided into two groups and predisposed to acute emotional stress. It was found that the contents of these peptides in Wistar-rats, which are more resistant to emotional stress, were higher compared with the August-rats, which are more predisposed to emotional stress. It was shown that the contents of beta-endorphin and DSIP in Wistar-rats is higher than in predisposed Wistar-rats.     

Ant (Hymenoptera: Formicidae) diversity and community composition along sharp urban forest edges

The effects of forest edge on ant species richness and community composition were examined within an urbanized area of northeast Ohio. The ground-dwelling ant fauna was inventoried in three deciduous forest fragments that have resulted from human disturbance. We surveyed ants via leaf-litter extraction along 150 m transects positioned perpendicular to the forest edge. We collected 4,670 individuals from 14 genera and 29 species. Samples closest to the forest edge contained more species and accumulated species at a higher rate than did samples located in the forest interior. Our rarefied and expected richness estimates revealed a decline of species richness from edge to forest interior. The higher ant richness at the forest edge was due mostly to the presence of species characteristic of the neighboring open habitats. Although most of the typical forest ant species were represented equally at the edge and at the forest interior, a few responded to the presence of edges with changes in their relative abundance and frequency of occurrence. Forest edges had a higher proportion of opportunistic species and a lower proportion of cryptic ants, whereas interior locations exhibited a more even distribution among ant functional groups. In addition, we documented a community composition shift between the edge and the forest interior. Consistent with previous findings, we suggest that the edge effects are most pronounced within 25 m of the forest edge, which may have implications for the overall conservation of forest-dwelling fauna.     

The effect of Bt crops on soil invertebrates: a systematic review and quantitative meta-analysis

The ongoing debate about the ecological effects of Bt-crops calls for thorough reviews about the impact on soil biodiversity and their ecosystem services. Transgenic Bt-crops have been genetically modified by inserting a Bacillus thuriengensis gene so the plant expresses a Cry toxin aimed for insect crop pests. Non-target soil invertebrates are particularly recognized for their contribution to plant nutrient availability and turnover of organic matter and it is therefore relevant to protect these invertebrate taxa. A number of studies have compared the population abundance and biomass of soil invertebrates in agricultural fields planted with genetically modified Bt crops and their conventional counterparts. Here, were review and analyze a selection of studies on Protista, nematodes, Collembola, mites, enchytraeids, and earthworms systematically to empower the evidence for asking the question whether population abundances and biomasses of soil invertebrates are changed by Bt crops compared to conventional crops. 6110 titles were captured, of which 38 studies passed our inclusion criteria, and a final number of 22 publications were subject to data extraction. A database with 2046 records was compiled covering 36 locations and the Bt types Cry1Ab, Cry1Ac, Cry3Bb1 and Cry3Aa. Comparative effect sizes in terms of Hedges’ g were calculated irrespectively of statistical significance of effects of the source studies. Cry effects on populations were compared across the studies in a meta-analysis employing a hierarchical Bayesian approach of weighted data according to the level of replication. The temporal development of effect sizes was modelled, thereby taking into account the variable duration of the field experiments. There was considerable variation among soil invertebrate orders, but the sample size was insufficient and the sample heterogeneity too large to draw any credible conclusions on the effect of Cry at the order level. However, across orders there was no significant effect of Cry on soil invertebrates.

     

2,3-Butanediol production from starch by engineered Klebsiella pneumoniae G31-A

2,3-Butanediol (2,3-BD) is an organic compound, which is widely used as a fuel and fuel additive and applied in chemical, food, and pharmaceutical industries. Contemporary strategies for its economic synthesis include the development of microbial technologies that use starch as cheap and renewable feedstock. The present work encompasses the metabolic engineering of the excellent 2,3-BD producer Klebsiella pneumoniae G31. In order to perform direct starch conversion into 2,3-BD, the amyL gene encoding quite active, liquefying α-amylase in Bacillus licheniformis was cloned under lac promoter control in the recombinant K. pneumoniae G31-A. The enhanced extracellular over-expression of amyL led to the highest extracellular amylase activity (68 U/ml) ever detected in Klebsiella. The recombinant strain was capable of simultaneous saccharification and fermentation (SSF) of potato starch to 2,3-BD. In SSF batch process by the use of 200 g/l starch, the amount of total diols produced was 60.9 g/l (53.8 g/l 2,3-BD and 7.1 g/l acetoin), corresponding to 0.31 g/g conversion rate. The presented results are the first to show successful starch conversion to 2,3-BD by K. pneumoniae in a one-step process.