Urban bat communities are affected by wetland size,quality, and pollution levels

Wetlands support unique biota and provide important ecosystem services. These services are highly threatened due to the rate of loss and relative rarity of wetlands in most landscapes, an issue that is exacerbated in highly modified urban environments. Despite this, critical ecological knowledge is currently lacking for many wetland‐dependent taxa, such as insectivorous bats, which can persist in urban areas if their habitats are managed appropriately. Here, we use a novel paired landscape approach to investigate the role of wetlands in urban bat conservation and examine local and landscape factors driving bat species richness and activity. We acoustically monitored bat activity at 58 urban wetlands and 35 nonwetland sites (ecologically similar sites without free‐standing water) in the greater Melbourne area, southeastern Australia. We analyzed bat species richness and activity patterns using generalized linear mixed‐effects models. We found that the presence of water in urban Melbourne was an important driver of bat species richness and activity at a landscape scale. Increasing distance to bushland and increasing levels of heavy metal pollution within the waterbody also negatively influenced bat richness and individual species activity. Areas with high levels of artificial night light had reduced bat species richness, and reduced activity for all species except those adapted to urban areas, such as the White‐striped free‐tailed bat (Austronomus australis). Increased surrounding tree cover and wetland size had a positive effect on bat species richness. Our findings indicate that wetlands form critical habitats for insectivorous bats in urban environments. Large, unlit, and unpolluted wetlands flanked by high tree cover in close proximity to bushland contribute most to the richness of the bat community. Our findings clarify the role of wetlands for insectivorous bats in urban areas and will also allow for the preservation, construction, and management of wetlands that maximize conservation outcomes for urban bats and possibly other wetland‐dependent and nocturnal fauna.     

Morphology and migration of podocytes are affected by CD151 levels

CD151, a member of the tetraspanin family of membrane proteins, is crucially involved in the formation of the glomerular filtration barrier in humans and mice. However, the role of CD151 in podocytes has not been investigated so far. In the present study, we utilized a conditionally immortalized mouse podocyte cell line to characterize CD151 in podocytes and to examine the consequences of manipulating CD151 expression levels. Mouse podocytes endogenously express CD151 as determined by RT-PCR and Western blotting. GFP-CD151 fusion protein localized to the cell membrane, to cell protrusions and cell-cell contacts, colocalizing with actin, β(1)-integrin, zonula occludens-1, and CD9. The expression of GFP-CD151 in cultured podocytes resulted in a marked increase in the presence of thin arborized protrusions (TAPs). TAPs are distinct from filopodia by increased length, protein composition, branched morphology, and slower dynamics. Furthermore, the migration rate of pEGFP-CD151-transfected podocytes was reduced in a wound assay. Fluorescence recovery after photo bleaching measurements revealed a half-time of 3 s for GFP-CD151 consistent with a high mobility of CD151 in the membrane and cytosol. CD151 knockdown in podocytes reduced β(1)-integrin expression and podocyte cell area, indicating diminished adherence and/or spreading. Our results indicate that CD151 importantly modulates podocyte function.     

17beta-oestradiol up-regulates longevity-related, antioxidant enzyme expression via the ERK1 and ERK2[MAPK]/NFkappaB cascade

Females live longer than males. Oestrogens protect females against aging by up-regulating the expression of antioxidant, longevity-related genes such as glutathione peroxidase (GPx) and Mn-superoxide dismutase (Mn-SOD). The mechanism through which oestrogens up-regulate those enzymes remains unidentified, but may have implications for gender differences in lifespan. We show that physiological concentrations of oestradiol act through oestrogen receptors to reduce peroxide levels in MCF-7 cells (a mammary gland tumour cell line). Oestradiol increases MAP kinase (MAPK) activation as indicated by ERK1 and ERK2 phosphorylation in MCF-7 cells, which in turn activates the nuclear factor kappa B (NFkappaB) signalling pathways as indicated by an increase in the p50 subunit of NFkappaB in nuclear extracts. Blockade of MAPK and NFkappaB signalling reduces the antioxidant effect of oestradiol. Finally, we show that activation of MAPK and NFkappaB by oestrogens drives the expression of the antioxidant enzymes Mn-SOD and GPx. We conclude that oestradiol sequentially activates MAPK and NFkappaB following receptor activation to up-regulate the expression of antioxidant enzymes, providing a cogent explanation for the antioxidant properties of oestrogen and its effects on longevity-related genes.     

异丙肾上腺素对小鼠心肌MAPK、NFκB和JAK/STAT信号转导途径的激活效应

为研究异丙肾上腺素(isoproterenol,ISO)诱导心肌肥厚或心肌重塑的分子机制,本工作以成年雄性Balh／c小鼠为研究对象,通过腹腔注射ISO,采用蛋白免疫印迹杂交方法观察ISO对小鼠心肌丝裂素活化蛋白激酶(mito-gen-activted protein kinase,MAPK)、核因子—κB(NFκB)和Janus激酶／信号转导因子和转录激活因子(JAK／STAT)途径的激活效应。结果发现,ISO腹腔注射后可早期(5min)激活心肌MAPK(ERK1／2和p38);ISO对心肌NFKB的激活效应表现为双相性,激活高峰分别为5和120min;ISO腹腔注射60min后可显著促进STAT3的酪氨酸磷酸化,6h时基本恢复到基础水平。上述结果提示,ISO对多种细胞内信号转导途径均具有激活效应,但表现出明显的时相差异。探明这些信号转导途径的时空整合规律,将有助于深化对心肌重塑发生机制的认识。     

Catalytic activities of Werner protein are affected by adduction with 4-hydroxy-2-nonenal

4-Hydroxy-2-nonenal (HNE) is a reactive α,β-unsaturated aldehyde generated during oxidative stress and subsequent peroxidation of polyunsaturated fatty acids. Here, Werner protein (WRN) was identified as a novel target for modification by HNE. Werner syndrome arises through mutations in the WRN gene that encodes the RecQ DNA helicase which is critical for maintaining genomic stability. This hereditary disease is associated with chromosomal instability, premature aging and cancer predisposition. WRN appears to participate in the cellular response to oxidative stress and cells devoid of WRN display elevated levels of oxidative DNA damage. We demonstrated that helicase/ATPase and exonuclease activities of HNE-modified WRN protein were inhibited both in vitro and in immunocomplexes purified from the cell extracts. Sites of HNE adduction in human WRN were identified at Lys577, Cys727, His1290, Cys1367, Lys1371 and Lys1389. We applied in silico modeling of the helicase and RQC domains of WRN protein with HNE adducted to Lys577 and Cys727 and provided a potential mechanism of the observed deregulation of the protein catalytic activities. In light of the obtained results, we postulate that HNE adduction to WRN is a post-translational modification, which may affect WRN conformational stability and function, contributing to features and diseases associated with premature senescence.     

Salmonella spp. are affected by different levels of water activity in closed microcosms

Controlling water activity (a _w) can significantly impact the growth of Salmonella in poultry litter and manure — a phenomenon that was studied quantitatively using two common serotypes of Salmonella. The quantitative effect of changes in levels of a _w on Salmonella populations was determined using inoculated, frosted glass rectangles placed in closed chambers (microcosms). Glass rectangles with known concentrations of Salmonella enteritidis and S. brandenburg were placed in microcosms maintained at an a _w level of 0.893 for 24 h at room temperature (RT) and then transferred to other microcosms maintained at the same temperature but with higher a _w levels (0.932 and 0.987). Salmonella populations on the slides were quantified at 4, 18, 24, and 48 h. Slightly elevated levels of a _w (<0.1, i.e., 10% equilibrium relative humidity) for 24 h resulted in a 100-fold increase in counts of Salmonella. The data also suggested that in vitro adaptation to dry environments may occur when the organisms are exposed to alternating levels of relatively high and low (0.987 and 0.893) levels of a _w. Any increased tolerance of Salmonella to reduced levels of a _w could be the result of physico-chemical changes in the organism due to selective environmental pressure, formation of a protective biofilm, and/or entry into a dormant state. Results from this study are compatible with those from previously reported on-farm surveys, reinforcing the contention that maintaining a _w below 0.85 in and around litter/manure surfaces in poultry or livestock bedding areas may be a critical factor in safe production of food. Journal of Industrial Microbiology & Biotechnology (2001) 26, 222–225. Received 18 May 2000/ Accepted in revised form 24 January 2001     

Lung compliance, plasma electrolyte levels and acid-base balance are affected by scorpion envenomation in anesthetized rats under mechanical ventilation

To determine the effects of Tityus serrulatus scorpion toxin on lung compliance and resistance, ionic equilibrium and acid-base balance over time in anesthetized and mechanically ventilated rats, we measured air flow, tracheal and esophageal pressure. Lung volume was obtained by electronic integration of airflow signal. Arterial blood samples were collected through a catheter at baseline (before) and 5, 15, 30 and 60 min after scorpion toxin injection for arterial blood gases, bicarbonate, and alkali reserve levels as well as for, sodium, potassium, magnesium, glucose, lactate, hematocrit, and osmolality analysis. Injection of the gamma fraction of the T. serrulatus scorpion venom in rats under mechanical ventilatory support leads to a continuous decrease in lung compliance secondary to pulmonary edema, but no change in airway resistance. The changes in arterial blood gases characterizing metabolic acidosis were accompanied by an increase in arterial lactate and glucose values, suggesting a scorpion toxin-induced lactic acidosis, in association with poor tissue perfusion (hypotension and low cardiac output). Moreover, scorpion toxin injection resulted in hyperosmolality, hyperkalemia, hypermagnesemia and an increase in hematocrit. The experiments have shown a clinically relevant animal model to study severe scorpion envenoming and may help to better understand the scorpion envenoming syndrome.     

Two activities of cofilin, severing and accelerating directional depolymerization of actin filaments, are affected differentially by mutations around the actin-binding helix

The biochemical activities of cofilin are controversial. We demonstrated that porcine cofilin severs actin filaments and accelerates monomer release at the pointed ends. At pH 7.1, 0.8 microM cofilin cut filaments (2.2 microM actin) about every 290 subunits and increased the depolymerization rate 6.4-fold. A kink in the major alpha-helix of cofilin is thought to constitute a contact site for actin. Side chain hydroxyl groups of Ser119, Ser120 and Tyr82 in cofilin form hydrogen bonds with main chain carbonyl moieties from the helix, causing the kink. We eliminated side chain hydroxyls by Ser-->Ala and/or Tyr-->Phe mutagenesis. Severing and depolymerization-enhancing activities were reduced dramatically in an Ala120 mutant, whereas the latter was decreased in a Phe82 mutant with a relatively small effect on severing, suggesting different structural bases for the two activities of cofilin. The Ala120-equivalent mutation in yeast cofilin affected cell growth, whereas that of the Phe82-equivalent had no effect in yeast. These results indicate the physiological significance of the severing activity of cofilin that is brought about by the kink in the helix.     

不同氮沉降水平下两种林型的主要土壤酶活性

模拟研究了天然阔叶红松林和天然次生杨桦林不同氮沉降（0、25和50 kg N·hm^-2·a^-1)水平下土壤酶活性(纤维素酶、多酚氧化酶和蔗糖酶)的变化趋势.结果表明：氮沉降增加对土壤酶活性的作用与林分类型有关,短期施氮可以显著影响土壤酶的活性;高氮沉降降低了土壤多酚氧化酶活性,且随着多酚氧化酶活性的降低,两种林型土壤纤维素酶和蔗糖酶活性也有降低的趋势.     

Spatio-temporal expression of patatin-like lipid acyl hydrolases and accumulation of jasmonates in elicitor-treated tobacco leaves are not affected by endogenous levels of salicylic acid

We have previously isolated three tobacco genes (NtPat) encoding patatin-like proteins, getting rapidly induced during the hypersensitive response (HR) to tobacco mosaic virus, in advance to jasmonate accumulation. NtPAT enzymes are lipid acyl hydrolases that display high phospholipase A2 (PLA2) activity and may mobilize fatty acid precursors of oxylipins. Here, we performed a detailed study of NtPat gene regulation under various biotic and abiotic stresses. PLA2 activity was poorly induced in response to drought, wounding, reactive oxygen intermediates, salicylic acid (SA) or methyl-jasmonate (MJ) whereas the ethylene (ET) precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), provoked a moderate induction. In contrast, PLA2 activity was strongly induced when ACC was combined with MJ, and in response to the bacterium Erwinia carotovora or to the fungus Botrytis cinerea, as well as to treatment with beta-megaspermin, a cell death-inducing protein elicitor. A simplified system based on the infiltration of beta-megaspermin into leaves was used to dissect the spatio-temporal activation of PLA2 activity with regards to the accumulation of jasmonates and to the influence of endogenous SA. NtPat-encoded PLA2 activity was rapidly induced in the infiltrated zone before the appearance of cell death and with some delay in the surrounding living cells. A massive accumulation of 12-oxo-phytodienoic and jasmonic acids occurred in the elicitor-infiltrated zone, but only low levels were detectable outside this area. A similar picture was found in SA-deficient plants, showing that in tobacco, accumulation of jasmonates is not affected by the concomitant HR-induced build-up of endogenous SA. Finally, ET-insensitive plants showed a weakened induction of PLA2 activity outside the elicitor-infiltrated tissue.     

Endogenous enzyme activities and polyamine levels in diverse rice cultivars depend on the genetic background and are not affected by the presence of the hygromycin phosphotransferase selectable marker

We used the polyamine biosynthetic pathway and rice as a relevant model to understand the genetic basis of variation in endogenous levels of metabolites and key enzymes involved in the pathway. Wild-type tissues and also tissues containing a commonly used selectable marker gene were employed. We detected a wide variation in levels of arginine decarboxylase activity and in the three polyamines, putrescine, spermidine and spermine, in different tissues and varieties, but this was not dependent on the presence of the selectable marker. A more-extensive profile of enzyme activities (ADC, ODC, SAMDC, DAO and PAO) and polyamine levels in different tissues was generated in two different varieties. Our results indicate that genetic background is important in terms of the basal levels of metabolites and enzyme activity, particularly in situations in which we aim to engineer metabolic pathways that are also encoded by homologous endogenous genes. We did not find any evidence that the presence of a selectable marker in any way influences enzyme activity or metabolite levels.     

Hepatocyte growth factor plasma levels after myocardial infarction are not affected by recombinant tissue-type plasminogen-activator therapy

Hepatocyte growth factor (HGF), a cytokine involved in tissue regeneration, angiogenesis and lateral vessel growth, is secreted as a biological-inactive, single-chain precursor named pro-HGF. In case, of tissue injury pro-HGF is proteolytically cleaved at the extracellular locus by serine proteases. Results obtained from in vitro experiments showed that urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) can cleave single-chain HGF. In this study we measured serum HGF levels in patients with acute myocardial infarction (MCI). Two groups of patients were compared. One group (n = 7) was treated with a conventional therapy and the other group (n = 7) was subjected to a thrombolytic therapy with recombinant tissue-type plasminogen activator (rtPA). Serum samples were collected at time of admission and subsequently 12-16 hours, 20-30 hours and 50-60 hours after onset of chest pain. At admission and before administration of rtPA, serum HGF levels peaked at 16.8 +/- 2.2 ng/ml in the lysed group and at 20.7 +/- 6.5 ng/ml in the non-lysed group. Levels then continuously declined, reaching lowest values 50-60 hours after onset of chest pain (3.2 +/- 1.3 ng/ml in the group treated with rtPA versus 4.4 +/- 0.9 ng/ml in the non-lysed group). No statistical significant difference could be detected between the two groups at any time. We suggest that serine proteases other than tPA are involved in HGF activation in vivo.     

Heat-induced expression and chemically induced expression of the Escherichia coli stress protein HtpG are affected by the growth environment.

Differences in expression of the Escherichia coli stress protein HtpG were found following exposure of exponentially growing cells to heat or chemical shock when cells were grown under different environmental conditions. With an htpG::lacZ reporter system, htpG expression increased in cells grown in a complex medium (Luria-Bertani [LB] broth) following a temperature shock at 45 degrees C. In contrast, no HtpG overexpression was detected in cells grown in a glucose minimal medium, despite a decrease in the growth rate. Similarly, in pyruvate-grown cells there was no heat shock induction of HtpG expression, eliminating the possibility that repression of HtpG in glucose-grown E. coli was due to catabolite repression. When 5 mM phenol was used as a chemical stress agent for cells growing in LB broth, expression of HtpG increased. However, when LB-grown cells were subjected to stress with 10 mM phenol and when both 5 and 10 mM phenol were added to glucose-grown cultures, repression of htpG expression was observed. 2-Chlorophenol stress resulted in overexpression of HtpG when cells were grown in complex medium but repression of HtpG synthesis when cells were grown in glucose. No induction of htpG expression was seen with 2, 4-dichlorophenol in cells grown with either complex medium or glucose. The results suggest that, when a large pool of amino acids and proteins is available, as in complex medium, a much stronger stress response is observed. In contrast, when cells are grown in a simple glucose mineral medium, htpG expression either is unaffected or is even repressed by imposition of a stress condition. The results demonstrate the importance of considering differences in growth environment in order to better understand the nature of the response to an imposed stress condition.     

NFkappaB negatively regulates interferon-induced gene expression and anti-influenza activity

Interferons (IFNs) are antiviral cytokines that selectively regulate gene expression through several signaling pathways including nuclear factor kappaB(NFkappaB). To investigate the specific role of NFkappaB in IFN signaling, we performed gene expression profiling after IFN treatment of embryonic fibroblasts derived from normal mice or mice with targeted deletion of NFkappaB p50 and p65 genes. Interestingly, several antiviral and immunomodulatory genes were induced higher by IFN in NFkappaB knock-out cells. Chromatin immunoprecipitation experiments demonstrated that NFkappaB was basally bound to the promoters of these genes, while IFN treatment resulted in the recruitment of STAT1 and STAT2 to these promoters. However, in NFkappaB knock-out cells IFN induced STAT binding as well as the binding of the IFN regulatory factor-1 (IRF1) to the IFN-stimulated gene (ISG) promoters. IRF1 binding closely correlated with enhanced gene induction. Moreover, NFkappaB suppressed both antiviral and immunomodulatory actions of IFN against influenza virus. Our results identify a novel negative regulatory role of NFkappaB in IFN-induced gene expression and biological activities and suggest that modulating NFkappaB activity may provide a new avenue for enhancing the therapeutic effectiveness of IFN.     

Reactions to children's faces: Males are more affected by resemblance than females are, and so are their brains

The detection of genetic relatedness (i.e., kinship) affects the social, parental, and sexual behavior of many species. In humans, self-referent phenotype matching based on facial resemblance may indicate kinship, and it has been demonstrated that facial resemblance increases perceptions of trustworthiness and attractiveness [Proc. R. Soc. Lond., B Biol. Sci. 269 (2002) 1307–1312; Proc. R. Soc. Lond., B Biol. Sci. (in press)]. However, investigations of sex differences in reaction to facial resemblance have produced mixed results [Evol. Hum. Behav. 25 (2004) 142–154; Evol. Hum. Behav. 23 (2002) 159–166; Evol. Hum. Behav. 24 (2003) 81–87]. Here, we replicate the effects of Platek et al. [Evol. Hum. Behav. 23 (2002) 159–166] using high-resolution color morphing. We also extend these findings using functional magnetic resonance imaging (fMRI) to demonstrate a possible neural mechanism that may account for the observed sex difference. These data support the hypothesis that human males may use and favor facial resemblance as a paternity cue.