bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent drought stress leads to growth reductions in Larix sibirica in the western Khentey, Mongolia
Authors: DULAMSUREN CHOIMAA , HAUCK MARKUS , LEUSCHNER CHRISTOPH 
Published: December 2009

AbstractTrends in air temperature and precipitation in the forest‐steppe ecotone of the western Khentey, northern Mongolia were studied and related to stem increment and shoot water relations in Mongolia's most common tree species, Siberian larch (Larix sibirica). The area has been subject to a significant increase of summer temperature and a decrease of summer precipitation during the last 47 years. Tree‐ring width series from >400 larch trees show a strongly decreasing annual increment since the 1940s. The onset of this decrease is independent of the age of the trees and, therefore, can be attributed to the increasing aridity in the 20th century. Simultaneously to the declining annual increment, regeneration of Siberian larch decreased as well; today regeneration is virtually lacking in the larch forests on mountain slopes of the western Khentey. Measurements of shoot water potentials during the growing season exhibited daily minimum water potentials close to the point of zero turgor for extended periods. The drought stress indicated by these results is in line with the current low annual increment. Trees in the forest interior were more severely stressed and grow more slowly than trees at the forest line to steppe. This is attributable to the recent increase in aridity, as the stand density and probably also the trees themselves in the forest interior are adapted to moister conditions, whereas the trees at the forest edge have always been exposed to a more extreme microclimate. The progressing increase in aridity during the 21st century that is predicted for the western Khentey, suggests a future decline of larch forests. A widespread increase of aridity predicted for most parts of the Mongolian forest belt, suggests even a supra‐regional decline of larch.
Photodegradation leads to increased carbon dioxide losses from terrestrial organic matter
Authors: RUTLEDGE SUSANNA , CAMPBELL DAVID I. , BALDOCCHI DENNIS , SCHIPPER LOUIS A. 
Published: December 2009

AbstractCO2 production in terrestrial ecosystems is generally assumed to be solely biologically driven while the role of abiotic processes has been largely overlooked. In addition to microbial decomposition, photodegradation – the direct breakdown of organic matter (OM) by solar irradiance – has been found to contribute to litter mass loss in dry ecosystems. Previous small‐scale studies have shown that litter degradation by irradiance is accompanied by emissions of CO2. However, the contribution of photodegradation to total CO2 losses at ecosystems scales is unknown. This study determined the proportion of the total CO2 losses caused by photodegradation in two ecosystems: a bare peatland in New Zealand and a seasonally dry grassland in California. The direct effect of solar irradiance on CO2 production was examined by comparing daytime CO2 fluxes measured using eddy covariance (EC) systems with simultaneous measurements made using an opaque chamber and the soil CO2 gradient technique, and with night‐time EC measurements under the same soil temperature and moisture conditions. In addition, a transparent chamber was used to directly measure CO2 fluxes from OM caused by solar irradiance. Photodegradation contributed 19% of the annual CO2 flux from the peatland and almost 60% of the dry season CO2 flux from the grassland, and up to 62% and 92% of the summer mid‐day CO2 fluxes, respectively. Our results suggest that photodegradation may be important in a wide range of ecosystems with exposed OM. Furthermore, the practice of partitioning daytime ecosystem CO2 exchange into its gross components by assuming that total daytime CO2 losses can be approximated using estimates of biological respiration alone may be in error. To obtain robust estimates of global ecosystem–atmosphere carbon transfers, the contribution of photodegradation to OM decomposition must be quantified for other ecosystems and the results incorporated into coupled carbon–climate models.
Range dynamics of small mammals along an elevational gradient over an 80‐year interval
Authors: ROWE REBECCA J. , FINARELLI JOHN A. , RICKART ERIC A. 
Published: December 2009

AbstractOne expected response to observed global warming is an upslope shift of species elevational ranges. Here, we document changes in the elevational distributions of the small mammals within the Ruby Mountains in northeastern Nevada over an 80‐year interval. We quantified range shifts by comparing distributional records from recent comprehensive field surveys (2006–2008) to earlier surveys (1927–1929) conducted at identical and nearby locations. Collector field notes from the historical surveys provided detailed trapping records and locality information, and museum specimens enabled confirmation of species' identifications. To ensure that observed shifts in range did not result from sampling bias, we employed a binomial likelihood model (introduced here) using likelihood ratios to calculate confidence intervals around observed range limits. Climate data indicate increases in both precipitation and summer maximum temperature between sampling periods. Increases in winter minimum temperatures were only evident at mid to high elevations. Consistent with predictions of change associated with climate warming, we document upslope range shifts for only two mesic‐adapted species. In contrast, no xeric‐adapted species expanded their ranges upslope. Rather, they showed either static distributions over time or downslope contraction or expansion. We attribute these unexpected findings to widespread land‐use driven habitat change at lower elevations. Failure to account for land‐use induced changes in both baseline assessments and in predicting shifts in species distributions may provide misleading objectives for conservation policies and management practices.
Plant functional group identity differentially affects leaf and root decomposition
Authors: McLAREN JENNIE R. , TURKINGTON ROY 
Published: December 2009

AbstractLosses of species and changes in the composition of plant communities are likely to influence numerous ecosystem functions. Changes in the plant‐soil interactions that control decomposition, in particular, could alter carbon and nutrient cycling in soils and further alter other ecosystem functions. The effects of plant communities on decomposition may depend both on the type of tissue being decomposed and also on the different stages of the decomposition process. We used an experimental design where single plant functional groups were removed from a northern grassland to examine the role of plant identity in determining both short‐term and long‐term above‐ and belowground decomposition rates. Plant removals were conducted across fertilization and fungicide treatments to examine environmental context‐dependency of functional group identity effects on decomposition. There were significant effects of plant functional group identity on aboveground decomposition, with the loss of grasses and forbs slowing decomposition, whereas the effects on belowground decomposition were rare and transient. Effects of plant identity on decomposition were consistent in both short‐ and long‐term decomposition studies indicating that the influences of identity on the decomposition environment remained consistent throughout the different stages of the decomposition process. Both fertilizer and fungicide treatments affected overall decomposition rate, but there were few interactions between these treatments and plant removals. Although current species loss is likely to be happening in concert with environmental changes, the role a species plays in determining ecosystem functions such as decomposition may not be context‐dependent in these northern environments, and this may provide greater predictive power in determining the effects of species loss with changing environments. Further, as plant identity shows significant effects on litter decomposition rates, the effects of current and predicted future biodiversity losses may depend specifically on which species are lost.
Erectile dysfunction and hormonal imbalance in morbidly obese male is reversed after gastric bypass surgery: a prospective randomized controlled trial
Authors: Reis L. O. , Favaro W. J. , Barreiro G. C. , De Oliveira L. C. , Chaim E. A. , Fregonesi A. , Ferreira U. 
Published: December 2009

SummaryThe effects of weight loss on erectile function and hormones have not been well studied. The aim of this study was to measure the degree to which sexual function and in particular erectile function and hormonal environment change after substantial weight loss, surgically and non‐surgically induced in the morbidly obese male in a prospective randomized long‐term controlled trial. Furthermore, how surgery makes a difference when treating morbidly obese men was envisaged in this context. We prospectively studied 20 morbidly obese men for 24 months, divided into two groups: group A included 10 patients who underwent life style modifications (exercise and diet) for 4 months and subsequently gastric bypass, and another 10 patients in group B were kept on weekly follow‐up. None of the men were taking phosphodiesterase type‐5 inhibitors. All patients underwent International Index of Erectile Function (IIEF)‐5 questionnaire, serum oestradiol, prolactin (PRL), luteinizing (LH) and follicle‐stimulating (FSH) hormones, free and total testosterone (FT and TT) at baseline (time 0), surgery – 4 months latter baseline (time 1) and final evaluation – 24 months (time 2). From times 0 to 1, group A presented a mean body mass index (BMI) reduction of 12.6 (p < 0.0001), whereas group B, 2.1 (p > 0.05). The BMI reductions between times 0 and 2 were 24.7 (p < 0.0001) and 0.7 (p > 0.05) for groups A and B respectively. BMI average between the two groups was similar at time 0 (p = 0.2142), and different at times 1 (p = 0.0033) and 2 (p < 0.0006). Increase in IIEF‐5 score (p = 0.0469), TT (p = 0.0349) and FSH levels (p = 0.0025), and reduction in PRL level (p < 0.0001) were observed in group A from times 0 to 2 and 1 to 2. There were no changes from times 0 to 1. Comparing groups A and B at time 2, IIEF‐5, TT and FT increased significantly in group A (p = 0.0224, 0.0043 and 0.0149 respectively). Surgery‐induced weight loss increased erectile function quality measured by IIEF‐5 questionnaire, increased TT, FT and FSH and reduced PRL levels. The hormonal impact verified could justify the improvement in erectile function. Lifestyle modifications impacted BMI without hormonal or sexual impact in morbidly obese. New studies are warranted in the field to support our data.
Bacillus subtilis ribonucleases J1 and J2 form a complex with altered enzyme behaviour
Authors: Mathy Nathalie , Hébert Agnès , Mervelet Peggy , Bénard Lionel , Dorléans Audrey , Li de la Sierra‐Gallay Inés , Noirot Philippe , Putzer Harald , Condon Ciarán 
Published: December 2009

SummaryRibonucleases J1 and J2 are recently discovered enzymes with dual 5′‐to‐3′ exoribonucleolytic/endoribonucleolytic activity that plays a key role in the maturation and degradation of Bacillus subtilis RNAs. RNase J1 is essential, while its paralogue RNase J2 is not. Up to now, it had generally been assumed that the two enzymes functioned independently. Here we present evidence that RNases J1 and J2 form a complex that is likely to be the predominant form of these enzymes in wild‐type cells. While both RNase J1 and the RNase J1/J2 complex have robust 5′‐to‐3′ exoribonuclease activity in vitro, RNase J2 has at least two orders of magnitude weaker exonuclease activity, providing a possible explanation for why RNase J1 is essential. The association of the two proteins also has an effect on the endoribonucleolytic properties of RNases J1 and J2. While the individual enzymes have similar endonucleolytic cleavage activities and specificities, as a complex they behave synergistically to alter cleavage site preference and to increase cleavage efficiency at specific sites. These observations dramatically change our perception of how these ribonucleases function and provide an interesting example of enzyme subfunctionalization after gene duplication.
An integrated regulatory network including two positive feedback loops to modulate the activity of σE in mycobacteria
Authors: Manganelli Riccardo , Provvedi Roberta 
Published: December 2009

SummaryσE, one of the best characterized mycobacterial extracytoplasmic function sigma factors, is involved in virulence, surface stress response and modulation of the inflammatory response during infection. The regulation of its activity is very complex and involves transcriptional, translational and post‐translational control. Post‐translational regulation is controlled by RseA, an anti‐σ factor belonging to the zinc‐associated anti‐σ factor family. In this issue of Molecular Microbiology, Barik et al. demonstrate that RseA is a redox‐sensing protein that is able to bind σE only in reducing environment. Importantly, they describe a novel positive feedback loop responsible for σE release and activation following surface stress, due to ClpC1P2‐dependent proteolytic degradation of RseA, depending on its phosphorylation by the eukaryotic‐like Ser/Thr protein kinase PknB.
The ribonucleases J1 and J2 are essential for growth and have independent roles in mRNA decay in Streptococcus pyogenes
Authors: Bugrysheva Julia V. , Scott June R. 
Published: December 2009

SummaryThe paralogous ribonucleases J1 and J2, recently identified in Bacillus subtilis, have both endoribonucleolytic and 5′‐to‐3′ exoribonucleolytic activities and participate in degradation and regulatory processing of mRNA. RNases J1 and J2 have partially overlapping target specificities, but only RNase J1 is essential for B. subtilis growth. Because mRNA decay is important in regulation of virulence factors of Streptococcus pyogenes (the group A streptococcus, GAS), we investigated the role of these newly described RNases in GAS. We found that conditional mutants for both RNases J1 and J2 require induction for growth, so we conclude that, unlike the case in B. subtilis, both of these RNases are essential for GAS growth, and therefore their functions are not redundant. We compared decay of representatives of the two classes of messages we had previously identified: Class I, which decay rapidly in exponential and stationary phase of growth (hasA and gyrA), and Class II, which are stable in stationary phase and exhibit a biphasic decay curve in exponential phase (sagA and sda). We report that RNases J1 and J2 affect the rate of decay of Class I messages and the length of the first phase in decay of Class II messages.
Deletion of dop in Mycobacterium smegmatis abolishes pupylation of protein substrates in vivo
Authors: Imkamp Frank , Rosenberger Tobias , Striebel Frank , Keller Peter M. , Amstutz Beat , Sander Peter , Weber‐Ban Eilika 
Published: December 2009

SummaryProteasome‐bearing bacteria make use of a ubiquitin‐like modification pathway to target proteins for proteasomal turnover. In a process termed pupylation, proteasomal substrates are covalently modified with the small protein Pup that serves as a degradation signal. Pup is attached to substrate proteins by action of PafA. Prior to its attachment, Pup needs to undergo deamidation at its C‐terminal residue, converting glutamine to glutamate. This step is catalysed in vitro by Dop. In order to characterize Dop activity in vivo, we generated a dop deletion mutant in Mycobacterium smegmatis. In the Δdop strain, pupylation is severely impaired and the steady‐state levels of two known proteasomal substrates are drastically increased. Pupylation can be re‐established by complementing the mutant with either DopWt or a Pup variant carrying a glutamate at its ultimate C‐terminal position (PupGGE). Our data show that Pup is deamidated by Dop in vivo and that likely Dop alone is responsible for this activity. Furthermore, we demonstrate that a putative N‐terminal ATP‐binding motif is crucial for catalysis, as a single point mutation (E10A) in this motif abolishes Dop activity both in vivo and in vitro.
Overlapping repressor binding sites regulate expression of the Methanococcus maripaludis glnK1 operon
Authors: Lie Thomas J. , Hendrickson Erik L. , Niess Ulf M. , Moore Brian C. , Haydock Andrew K. , Leigh John A. 
Published: December 2009

SummaryThe euryarchaeal transcriptional repressor NrpR regulates a variety of nitrogen assimilation genes by 2‐oxoglutarate‐reversible binding to conserved palindromic operators. The number and positioning of these operators varies among promoter regions of regulated genes, suggesting NrpR can bind in different patterns. Particularly intriguing is the contrast between the nif and glnK1 promoter regions of Methanococcus maripaludis, where two operators are present but with different configurations. Here we study NrpR binding and regulation at the glnK1 promoter, where the two operator sequences overlap and occur on opposite faces of the double helix. We find that both operators function in binding, with a dimer of NrpR binding simultaneously to each overlapping operator. We show in vivo that the first operator plays a primary role in regulation and the second operator plays an enhancing role. This is the first demonstration of overlapping operators functioning in Archaea.
The prevalence of red cell antigens and antibodies in Malawi
Authors: M'baya B. , Mfune T. , Mogombo E. , Mphalalo A. , Ndhlovu D. , Knight R. C. 
Published: December 2009

As there were no reliable data in Malawi for the prevalence of red cell alloantibodies or antigens in the population, a study was conducted to screen 1000 patients for the presence of antibodies and to type them for ABO, RhD, C, c, E, e and K antigens and to test 500 donors for these antigens plus Fya, Fyb, Jka, Jkb, S and s.Red cell antibodies were identified in 11 patients [1.1%]; 2 were anti‐D, 2 anti‐S, 1 anti‐Lea+b and 6 anti‐M, 4 of which were found in non‐transfused males suggesting they might be naturally acquired.The antigen frequencies found were similar to those previously published for Central Africa but 98.2% of donors were found to be Fy(a‐b‐). All patients tested were K negative and only three donors were found to be K positive, one being a Caucasian. Approximately 3.5% of Malawians are D negative, lower than the usual 8% quoted for Black Africans.These data confirm the assumption that pre‐transfusion antibody screening is not currently required but that use of the indirect antiglobulin test in the cross‐match is necessary. Haemolytic disease of the newborn (HDN) appears to be rare, or under reported, in Malawi, and more work is needed to find the real incidence of this condition.
Treatment of canine generalized demodicosis with a ‘spot‐on’ formulation containing 10% moxidectin and 2.5% imidacloprid (Advocate®, Bayer Healthcare)
Authors: Mueller Ralf S. , Meyer Daniela , Bensignor Emmanuel , Sauter‐Louis Carola 
Published: December 2009

AbstractIn this multicentre study, the efficacy of a spot‐on formulation containing 10% imidacloprid and 2.5% moxidectin (Advocate®, Bayer HealthCare) was evaluated for the treatment of dogs with generalized demodicosis. The spot‐on was applied every 2 weeks. Secondary bacterial infections were diagnosed by clinical examination, cytology and bacterial culture as appropriate and treated with oral antibiotics. Improvement or deterioration was determined monthly by clinical scores and by assessing mite numbers on microscopy of skin scrapings. Seventy‐two dogs were included in the study. Fifty‐two dogs had juvenile‐onset demodicosis (mean of 11 months, range 2–24 months) and 20 dogs were adults at onset of disease (mean of 8.6 years, range 3.5–14 years). Twenty‐six dogs went into remission, three with adult‐onset demodicosis, 23 with juvenile‐onset. The latter group showed significantly higher remission rates (P = 0.0252). Time until remission varied from 4 to 32 weeks (mean of 12.5 weeks). Dogs with a clinical score of <45 at the beginning of the study showed a significantly better response to the treatment (P = 0.0004), with a remission rate of 71%. In contrast, only 24% of those dogs with a score >45 went into remission. Adverse effects were not observed. One of the dogs responding to treatment showed recurrence of the disease during a follow‐up period of 12 months. This study shows a better success rate of Advocate®in dogs with mild clinical signs, versus those with moderate to severe clinical signs.
Unravelling the skin barrier: a new paradigm for atopic dermatitis and house dust mites
Authors: Marsella Rosanna , Samuelson Don 
Published: December 2009

AbstractAtopic dermatitis (AD) is a chronic relapsing inflammatory skin disease caused by complex interactions between genetics and environmental factors. In human beings, impairment of the skin barrier is demonstrated and thought to be responsible for enhanced penetration of allergens and increased risk for allergic sensitization. Once inflammation is triggered, further impairment of the skin barrier occurs, leading to self‐perpetuating cycles of sensitizations. Canine AD appears to share many similarities with the human counterpart, clinically and immunologically. It is hypothesized that a primary defect of skin barrier function also exists in subsets of atopic dogs (e.g. in an experimental model using high IgE‐producing beagles), particularly in young dogs, and in sites predisposed to the development of lesions. This impairment is present in clinically normal skin, worsens with development of lesions and can be quantified by measurement of transepidermal water loss. Therefore, the distribution of lesions in AD may be linked to a primary skin barrier defect in those sites and not simply due to contact with allergens, and increased susceptibility to penetration of allergen may exist early in life. Ultrastructurally, transmission electron microscopy reveals that clinically normal skin in atopic dogs has abnormalities in lamellar body secretion and extracellular lamellar bilayer structure when compared with normal dogs. Development of lesions worsens these changes (e.g. widening of intercellular spaces, release of lamellar bodies, and disorganization of lipid lamellae). It is proposed that the paradigm of canine AD as primarily due to immunologic aberration (‘inside/outside’) should be shifted to include a primary defect in barrier function (‘outside/inside’).