bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic variability in Irish populations of the invasive zebra mussel,Dreissena polymorpha: discordant estimates of population differentiation from allozymes and microsatellites
Authors: GOSLING ELIZABETH , ASTANEI IULIAN , WAS ANNA 
Published: February 2008

Summary1. The recent arrival and explosive spread of the zebra mussel,Dreissena polymorpha(Pallas), in Ireland provided a rare opportunity to study the population genetics of an invasive species.2. Eight polymorphic allozyme loci (ACO‐1, ACO‐2,EST‐D, GPI, IDH‐2, MDH, OPDHandPGM) were used to investigate genetic diversity and population structure in five Irish populations, and the results were compared with those from a previous microsatellite study on the same samples.3. The mean number of alleles per locus (2.7 ± 0.1) was similar to the mean for the same loci in European populations, suggesting that Irish founder populations were large and/or multiple colonization events took place after foundation. A deficiency of heterozygotes was observed in all populations, but was uneven across loci.4. Pairwise comparisons, using Fisher’s exact tests andFSTvalues, revealed significant genetic differentiation among populations. The overall multilocusFSTestimate was 0.118 ± 0.045, which contrasted with an estimate of 0.015 ± 0.007 from five microsatellite loci on the same samples in a previous study.5. Assuming that microsatellites can be used as a neutral baseline, the discordant results from allozymes and microsatellites suggest that selection may be acting on some allozyme loci, specificallyACO‐1, ACO‐2,IDH‐2andMDH,which contributed most to the significant differentiation between samples.
Effects of flooding on avian top‐predators and their invertebrate prey in a monsoonal Taiwan stream
Authors: CHIU MING‐CHIH , KUO MEI‐HWA , SUN YUAN‐HSUN , HONG SHIAO‐YU , KUO HIH‐CHUAN 
Published: February 2008

Summary1. The effects of flooding on top predators are poorly understood globally, but particularly in monsoonal streams. We therefore attempted to assess how inter‐annual and intra‐annual variations in flood magnitude affected an obligate riverine predator, the brown dipper (Cinclus pallasii), and its invertebrate prey, in the mountain Tachia River, Taiwan. Major flooding in one of the study years (2005) allowed an insight into the effects of abnormally large flows.2. The abundance and biomass of insects, and the abundance of dippers, decreased steadily from 2003 to 2005 as flood magnitude grew, but then increased in 2006 when more typical discharge returned. Dipper abundance, insect abundance and insect biomass were all strongly positively inter‐related, but negatively related to discharge. Insect biomass, rather than abundance, was more useful in predicting brown dipper abundance.3. Aquatic insect composition fluctuated among sampling years, revealed by non‐metric multidimensional scaling, and these fluctuations were also related to discharge. In turn, dipper abundance and the mean body size of aquatic insects declined with the shift in insect composition as flow increased.4. These data illustrate how discharge fluctuations can have pronounced effects on top predators in streams, mediated in this case by fluctuating prey abundance. While contributions from bird movement, breeding performance and mortality were not clearly differentiated, our data reveal how dippers have strategies to accommodate varying discharge in river systems. We suggest that the effects of floods on dippers should be taken into account when using this group as indicators of river quality.
E3 ubiquitin ligase E6AP‐mediated TSC2 turnover in the presence and absence of HPV16 E6
Authors: Zheng Li , Ding Huirong , Lu Zheming , Li Yong , Pan Yaqi , Ning Tao , Ke Yang 
Published: February 2008

We previously found that HPV16 E6 causes the degradation of the tumor suppressor protein TSC2, resulting in the phosphorylation of S6 kinase and S6 even in the absence of insulin. In the present study, we investigated the role of E6‐associated protein (E6AP) in HPV16 E6‐induced TSC2 degradation. Our results demonstrated that TSC2 was targeted for degradation in the presence or absence of HPV16 E6. Over‐expression of E6AP enhanced the degradation of TSC2 by HPV16 E6, while expression of a dominant negative E6AP (C833A) inhibited the E6‐induced degradation. Additionally, by using shRNAs to block E6AP expression in HPV16 positive and negative cells, we found a significantly prolonged TSC2 half‐life. An in vivo ubiquitination assay was done to reveal that E6AP promoted the ubiquitination of TSC2 independent of HPV16 E6. We further found that TSC2 bound E6AP in the presence as well as in the absence of HPV16 E6. The binding regions on E6AP and TSC2 have been identified as amino acid (aa) 260–316, aa 428–500 and aa 1–175, aa 1251–1807, respectively. Taken together, degradation of TSC2 is mediated by E6AP ubiquitin ligase.
Combination of Clk family kinase and SRp75 modulates alternative splicing of Adenovirus E1A
Authors: Yomoda Jun‐ichiro , Muraki Michiko , Kataoka Naoyuki , Hosoya Takamitsu , Suzuki Masaaki , Hagiwara Masatoshi , Kimura Hiroshi 
Published: February 2008

SR proteins are non‐snRNP splicing factors harbouring a domain rich in Arg‐Ser repeats, which are extensively phosphorylated by several kinases. We performed a comparative study of different SR kinases, including SRPK, Clk, PRP4 and DYRK, and found that only Clks efficiently altered 5′ splice site selection of Adenovirus E1A. The phosphorylation state of SR proteins was examined using a phospho‐SR specific antibody mAb1H4 and a 75 kDa protein was most evidently hyperphosphorylated by Clks. Administration of TG003, a specific inhibitor for the Clk family members, specifically and rapidly induced dephosphorylation of 75 kDa SR protein. Imaging with mRFP‐SRp75 in living cells revealed that its nuclear distribution was rapidly altered upon inhibition of the Clk activity by TG003. Co‐transfection experiments demonstrated that HA‐tagged SRp75 was hyperphosphorylated by Clk family members, but not by other SR kinases. These results indicate that Clks specifically hyperphosphorylate SRp75. Furthermore, SRp75 over‐expression promoted the selection of 12S 5′ splice site in E1A pre‐mRNA, which is stimulated by co‐expression of Clks. These results suggest that the specific combination of SR protein and SR kinase plays a distinct role in alternative splicing through dynamic balance of phosphorylation.
Interactions of elevated carbon dioxide and temperature with aphid feeding on transgenic oilseed rape: Are Bacillus thuringiensis (Bt) plants more susceptible to nontarget herbivores in future climate?
Authors: HIMANEN SARI J. , NISSINEN ANNE , DONG WEN‐XIA , NERG ANNE‐MARJA , STEWART C. NEAL , POPPY GUY M. , HOLOPAINEN JARMO K. 
Published: February 2008

AbstractClimate change factors such as elevated carbon dioxide (CO2) and temperature typically affect carbon (C) and nitrogen (N) dynamics of crop plants and the performance of insect herbivores. Insect‐resistant transgenic plants invest some nutrients to the production of specific toxic proteins [i.e. endotoxins from Bacillus thuringiensis (Bt)], which could alter the C–N balance of these plants, especially under changed abiotic conditions. Aphids are nonsusceptible to Lepidoptera‐targeted Bt Cry1Ac toxin and they typically show response to abiotic conditions, and here we sought to discover whether they might perform differently on compositionally changed Bt oilseed rape. Bt oilseed rape had increased N content in the leaves coupled with reduced total C compared with its nontransgenic counterpart, but in general the C : N responses of both plant types to elevated CO2 and temperature were similar. Elevated CO2 decreased N content and increased C : N ratio of both plant types. Elevated temperature increased C and N contents, total chlorophyll and carotenoid concentrations under ambient CO2, but decreased these under elevated CO2. In addition, soluble sugars were increased and starch decreased by elevated temperature under ambient but not under elevated CO2, whereas photosynthesis was decreased in plants grown under elevated temperature in both CO2 levels. Myzus persicae, a generalist aphid species, responded directly to elevated temperature with reduced developmental time and decreased adult and progeny weights, whereas the development of the Brassica specialist Brevicoryne brassicae was less affected. Feeding by M. persicae resulted in an increase in the N content of oilseed rape leaves under ambient CO2, indicating the potential of herbivore feeding itself to cause allocation changes. The aphids performed equally well on both plant types despite the differences between C–N ratios of Bt and non‐Bt oilseed rape, revealing the absence of plant composition‐related effects on these pests under elevated CO2, elevated temperature or combined elevated CO2 and temperature conditions.
Forest transition in Vietnam and its environmental impacts
Authors: MEYFROIDT PATRICK , LAMBIN ERIC F. 
Published: February 2008

AbstractThis study assesses the presence of a forest transition – that is, a shift from net deforestation to net reforestation – in Vietnam during the 1990s, and describes its key attributes relevant for global environmental change issues. Using Fuzzy Kappa and other indicators, we compared forest cover estimates and spatial patterns from global and national land cover maps from the early and late 1990s, and compiled other available statistics for years before and after that period. This showed that a forest transition indeed occurred in Vietnam: the forest cover dropped to 25–31% of the country area in 1991–1993, and then increased to 32–37% in 1999–2001. The reforestation occurred at a higher rate than deforestation in the previous decades, and was due in similar proportions, to natural forest regeneration and to planted forests. The carbon stock in forests followed a similar transition, decreasing to 903 (770–1307) Tg C in 1991–1993, and then increasing to 1374 (1058–1744) Tg C in 2005. However, forest density declined during the same period, with an increasing proportion of young and degraded forests. The effects on habitats measured with landscape pattern indices were contrasted: in several regions, the reforestation decreased forest fragmentation, while in others, clearing of old‐growth forests continued and/or forest fragmentation increased. This shows that a transition in forest area is not sufficient to rehabilitate the different ecosystem functions and services of forests. Other forest transitions exist in Tropical Asia and in Latin America. Knowledge about the causes, pattern and environmental impacts of the forest transition in Vietnam is therefore relevant to understand possible emerging regional trends that would have implications for global environmental change.
Multiple anthropogenic changes cause biodiversity loss through plant invasion
Authors: Van Der WAL RENÉ , TRUSCOTT ANNE‐MARIE , PEARCE IMOGEN S. K. , COLE LISA , HARRIS MIKE P. , WANLESS SARAH 
Published: February 2008

AbstractNon‐native invasive plants are a widely acknowledged threat to global biodiversity. However, our understanding of the mechanisms underlying plant invasion, and the relative importance of multiple rather than single drivers, remains poor. Here, we provide a case study using time‐series data to reconstruct patterns of change, and field experiments to test for causality. We show how, over a 50‐year period, a series of unrelated human‐induced changes created highly favorable conditions for the non‐native tree mallow (Lavatera arborea) to turn invasive, causing loss of native vegetation and seabird breeding habitat. The combination of three drivers: human‐introduced disease, climate warming and a fisheries‐mediated increase in seabird populations, removed major constraints on plant population growth, (i.e. grazer control, climatic control, germination opportunity and nutrient limitation). Collectively, these changes created optimal conditions for the rapid expansion of tree mallow. The resulting dramatic impact on both the native vegetation and breeding seabirds, notably puffins (Fratercula arctica), exemplifies how non‐native invasive plant species can transform terrestrial ecosystems. While climate change is regarded as a key factor behind plant invasion, we highlight that multiple rather than single factors may be critical to biodiversity loss.
Influence of simulated snow cover on the cold tolerance and freezing injury of yellow‐cedar seedlings
Authors: SCHABERG PAUL G. , HENNON PAUL E. , D'AMORE DAVID V. , HAWLEY GARY J. 
Published: February 2008

AbstractIt has been hypothesized that yellow‐cedar [Chamaecyparis nootkatensis (D. Don) Spach] decline may result from root freezing injury following climate change‐induced reductions in protective snow cover. To test this hypothesis, we measured the freezing tolerance and injury expression of yellow‐cedar seedlings in three treatments that differed in the insulative protection they provided to soils during winter and spring: (1) full exposure to ambient temperatures (exposed treatment), (2) continuous protection from ambient temperatures via addition of perlite over pots (full protection), and (3) perlite protection only during winter and exposure to ambient temperatures during spring (partial protection). Foliage from all treatments was cold tolerant enough to prevent foliar freezing injury throughout the study period. However, on all sample dates, roots of seedlings from all treatments were only tolerant to about −5 °C – a level considerably warmer than the reported maximum cold tolerance for the species and well above the soil temperature recorded in the exposed treatment. As a result of this limited root cold tolerance, visibly uninjured roots of seedlings from the exposed treatment had significantly higher relative electrolyte leakage (REL) throughout the winter and early spring than seedlings in soil protection treatments. Seedlings from the exposed treatment also had significantly higher foliar REL values and greater visual foliar injury than seedlings from the other treatments starting in early spring. For both roots and foliage, REL measurements consistently detected tissue damage before visual injury was evident. Patterns of injury from both REL and visual injury assessments showed the same pattern: damage began with freezing injury to roots and subsequently became evident as foliar browning after spring temperatures increased. All seedlings in the exposed treatment eventually had 100% fine root damage and died. This progression of initial root damage followed by foliar browning and mortality after the onset of warming conditions is consistent with reports of yellow‐cedar decline symptom development in the field.
Blockade of epithelial sodium channels improves sperm motility in asthenospermia patients
Authors: Kong Xiang‐Bin , Ma Hua‐Gang , Li Hong‐Gang , Xiong Cheng‐Liang 
Published: February 2008

SummaryEpithelial Na+ channels (ENaCs) are ion channels that play important roles in physiology as well as pathophysiology. Inhibiting ENaCs using amiloride and its derivatives has been suggested in treatment of cardivascular disease and hypertension. By immunoblotting, we demonstrated the presence of ENaC‐α protein in the flagellar midpiece of both rat and human sperm. Immunohistochemistry analyses in rat testis localized ENaC‐α expressed in the Leydig cell, Sertoli cell, Ap spermatogonium, spermatocyte, spermatid and residual body. Importantly, using computer‐assisted sperm motility analysis, we first observed that EIPA [5‐(N‐ethyl‐N‐isopropyl)‐amiloride hydrochloride] inhibition of ENaCs, possibly including ENaC‐α and ENaC‐δ, significantly improved the sperm motility in healthy donors by 14.23% (mean ± SEM, 68.75 ± 9.76% vs. 78.53 ± 6.20%, p < 0.001) and in asthenospermia patients by 115.89% from 9.50 ± 6.11% to 20.51 ± 12.13% (mean ± SEM, p < 0.001). The improved sperm motility by EIPA has important clinical implications in the treatment of asthenospermia and certainly warrants further investigation.
Assessment of erectile dysfunction in diabetic patients
Authors: Hamdan Farqad B. , Al‐Matubsi Hisham Y. 
Published: February 2008

SummaryErectile dysfunction (ED) aetiology is multifactorial, including endocrine, neurological, vascular, systemic disease, local penile disorders, nutrition, psychogenic factors, and drug‐related. This study was performed to compare the relevant comprehensive biochemical parameters as well as the clinical characteristics in diabetic ED and healthy control subjects and to assess the occurrence of penile neuropathy in diabetic patients and thus the relationship between ED and diabetes. A total of 56 patients accepted to undergo assessment for penile vasculature using intracavernosal injection and colour Doppler ultrasonography. Of the 56 diabetic patients, 38 patients were found with normal blood flow and thus they were considered as the diabetic‐ED group, whereas, ED diabetic patients with an arteriogenic component were excluded. These patients with an age range between 17 and 58 years, complaining of ED, with duration of diabetic illness ranging from 2 to 15 years. The Control group comprised of 30 healthy subject aged between 19 and 55 years. Peripheral venous levels of testosterone, prolactin, follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), malondialdehyde and glycosylated haemoglobin (HbA1c) were obtained in all subjects. Valsalva manoeuvre and neurophysiological tests were also determined. Testosterone, prolactine, FSH, LH, and TSH hormones of the diabetic patients were not significantly different from those of the control group. Diabetic patients with ED have higher HbA1c and oxidative stress levels while the R‐R ratio was significantly decreased. Bulbocavernosus reflex latency was significantly prolonged, whereas its amplitude, the conduction velocity and amplitude of dorsal nerve of penis were significantly reduced in the diabetic patients. We concluded that although ED is a multifactorial disorder, yet, the present study revealed that in ED patients without arteriogenic ED a neurogenic component is present. Furthermore, the complex effect of the Valsalva manoeuvre on cardiovascular function is the basis of its usefulness as a measure of autonomic function. Thus, it can be of value in the diagnosis of ED although these hypotheses require follow‐up in a large study cohort.
Patterns of release of the secondary conidia of Claviceps africana, the sorghum ergot pathogen in Australia
Authors: Ryley M. J. , Chakraborty S. 
Published: February 2008

Trials were conducted in southern Queensland, Australia between March and May 2003, 2004 and 2005 to study patterns of hourly and daily release of the secondary conidia of Claviceps africana and their relationships with weather parameters. Conidia were trapped for at least one hour on most (> 90%) days in 2003 and 2004, but only on 55% of days in 2005. Both the highest daily concentration of conidia, and the highest number of hours per day when conidia were trapped, were recorded 1–3 days after rainfall events. Although the pattern of conidial release was different every day, the highest hourly conidial concentrations occurred between 10·00 hours and 17·00 hours on 73% of all days in the three trials. Hours when conidia were trapped were characterized by higher median values of temperature, windspeed and vapour pressure deficit, lower relative humidity, and leaf wetness values of 0%, than hours when no conidia were recorded. The results indicate that fungicides need to be applied to the highly ergot‐susceptible male sterile (A‐) lines of sorghum in hybrid seed production blocks and breeders’ nurseries as soon as possible after rainfall events to minimize ergot severity.
Quantification of ToxB gene expression and formation of appressoria by isolates of Pyrenophora tritici‐repentis differing in pathogenicity
Authors: Amaike S. , Ozga J. A. , Basu U. , Strelkov S. E. 
Published: February 2008

Tan spot, caused by the fungus Pyrenophora tritici‐repentis, is an important foliar disease of wheat. The pathogen produces at least three host‐specific toxins, including Ptr ToxB, a 6·6 kDa protein that causes chlorosis in sensitive wheat genotypes and is encoded by the ToxB gene. Using quantitative reverse transcriptase (qRT)‐PCR, transcript levels of ToxB homologues found in virulent (≡ pathogenic) and weakly virulent (≡ weakly pathogenic) race 5 isolates and an avirulent (≡ nonpathogenic) race 4 isolate of the fungus were compared in conidia, mycelia, and in host tissues after inoculation of resistant and susceptible wheat genotypes. Abundance of the ToxB transcript was greatest in the virulent isolate, followed by the weakly virulent and avirulent isolates, and was positively correlated with the development of chlorosis in the susceptible wheat genotype; transcript was detectable in mycelia and conidia of all isolates tested, and levels peaked at 24 h after inoculation of the race 5 isolates onto resistant and susceptible wheat hosts, before disease symptoms developed. Although all isolates could penetrate host epidermal cells to varying degrees, transcript abundance was positively correlated with the greater and more rapid development of appressoria. Therefore Ptr ToxB may have other roles in the basic pathogenic fitness of the fungus and/or in pre‐penetration processes, suggesting that quantitative variation in the virulence of P. tritici‐repentis is related to the extent of ToxB gene expression.
Silencing RNA‐directed RNA polymerase 2 increases the susceptibility of Nicotiana attenuata to UV in the field and in the glasshouse
Authors: Pandey Shree P. , Baldwin Ian T. 
Published: February 2008

SummaryRNA‐directed RNA‐polymerases (RdRs) are essential in small interfering RNA (siRNA) biogenesis and appear to be functionally specialized. We examined the consequences of silencing RdR2 in Nicotiana attenuata with a field release, and transcriptional, two‐dimensional proteomic and metabolite analyses. NaRdR2‐silenced plants (irRdR2) had large reductions (46% of wild type) in 22–24‐nt small RNAs (smRNAs), and smaller reductions (35, 23 and 26% of wild type) in the 19–21, 25–27 and 28–30‐nt smRNAs, respectively. When planted into their native habitats in the Great Basin Desert, irRdR2 plants had impaired growth and reproductive output, which were associated with reduced levels of leaf phenolics (rutin and 4′‐chlorogenic acid) and MYB and PAL transcripts, but were unaffected in their herbivore resistance. These phenotypes were confirmed in glasshouse experiments, but only when irRdR2 plants were grown with UV‐B radiation. irRdR2 plants had wild‐type levels of elicited phytohormones and resistance to Manduca sexta attack, but when exposed to UV‐B, had reduced growth, fitness, levels of MYB and PAL transcripts, and phenolics. Proteins related to protection against oxidative and physiological stresses, chromatin remodeling and transcription were also downregulated. Silencing the MYB gene by virus‐induced gene silencing (VIGS) in wild‐type plants reduced levels of PAL transcripts and phenolics, as it did in UV‐exposed irRdR2 plants. Bioinformatic analysis revealed that genes involved in phenylpropanoid biosynthesis contained a large number of smRNA binding motives, suggesting that these genes are targets of smRNAs. We conclude that although NaRdR2 transcripts are upregulated in response to both UV‐B and herbivore elicitation, the responses they regulate have been tailored to provide protection from UV‐B radiation.