bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accentuation of phosphorus limitation in Geranium dissectum by nitrogen: an ecological genomics study
Authors: THAYER SUSAN SUMMERS , ST CLAIR SAMUEL B. , FIELD CHRISTOPHER B. , SOMERVILLE SHAUNA C. 
Published: April 2008

AbstractGlobal climate change experiments have shown changes in productivity, phenology, species composition, and nutrient acquisition and availability; yet, the underlying mechanisms for these responses, especially in multi‐factorial experiments, are poorly understood. Altered nutrient availability is a major consequence of global change, directly due to anthropogenic nitrogen (N) deposition, and indirectly due to shifts in temperature and water availability. In the Jasper Ridge Global Change Experiment, microarrays were used to investigate the transcriptional responses of the dominant dicot, Geranium dissectum, to simulated N deposition. The transcript levels for several photosynthetic genes were elevated in plants exposed to elevated N, as has been reported previously, validating the use of microarrays under field conditions. A coordinated response of a suite of genes previously reported to be induced in response to phosphate (Pi) deficiency was observed, including genes for the glycolytic bypass pathway, which reduces ATP and Pi requirements for sugar degradation, suggesting that the plants were phosphorus (P) limited. Confirming this conclusion, foliar P levels in G. dissectum leaves were reduced to levels that are suboptimal for growth in plants grown in elevated N and elevated CO2 plots. Thus, although plants commonly produce more biomass in response to elevated N in native grasslands, this growth response may be suboptimal due to a P limitation. Foliar P levels in plants from elevated CO2 plots were also suboptimal for growth. However, genes indicative of Pi deficiency were not significantly expressed at higher levels. Transcript levels for genes involved in nitrate uptake and assimilation were unchanged by the elevated N deposition treatment, possibly due to the combined impacts of elevated N deposition and P limitation under field conditions. These observations highlight the complexity of the impact of global climate change factors in the field.
Warming increases aboveground plant biomass and C stocks in vascular‐plant‐dominated Antarctic tundra
Authors: DAY THOMAS A. , RUHLAND CHRISTOPHER T. , XIONG FUSHENG S. 
Published: April 2008

AbstractWe passively warmed tundra on the Antarctic Peninsula over four growing seasons and assessed its effect on dry mass and C and N stocks associated with the vascular plants Colobanthus quitensis (a cushion‐forming forb) and Deschampsia antarctica (a tussock grass), and mosses. Temperature treatments involved a warmed treatment that raised diurnal and diel canopy air temperatures by 2.3 and 1.3 °C, respectively, and a near‐ambient temperature treatment that raised diurnal and diel temperatures by 0.2 °C. These two different temperature regimes were achieved by wrapping filters around the frames to different extents and were nested within three UV treatments that filtered different solar UV wavebands. The experiment also included an ambient control treatment (unfiltered frames), and supplemental water and fertilizer treatments (applied to unfiltered frames). After four growing seasons, we collected cores of each vascular plant species and assessed the mass and C and N content of the aboveground current‐year biomass, the litter layer (which included nongreen live stems), and the organic soil horizon (which included roots). The thin nature of the organic soil horizon allowed us to sample this complete horizon and estimate near‐total ecosystem C and N stocks. A comparison of the warmed and near‐ambient temperature treatments found that warming led to greater aboveground biomass of C. quitensis, and more C in the aboveground biomass of both vascular plant species. Warming resulted in lower N concentrations of the aboveground biomass of both species. The water use efficiency of both species was greater under warming, based on their higher δ13C values. The mass of the litter layer under C. quitensis was greater under warming, and this layer contained more C and N and had a higher C : N ratio. The mass of the organic soil horizon under both species was greater under warming, and this horizon also contained more C and N. Warming also changed the species composition of the plant community – cover of C. quitensis increased while that of mosses declined. Warming resulted in the input of biomass into the system that had greater C : N ratios (and was likely more recalcitrant to decomposition) because (1) warming increased the C : N ratio of the biomass produced by both vascular plant species, (2) these inputs increased with warming because of greater biomass production, and (3) increases in C. quitensis cover led to greater biomass inputs by this species and its biomass had a greater C : N ratio than D. antarctica. Water or fertilizer supplements had few effects on aboveground biomass or C and N concentrations or pools, consistent with the relatively wet maritime climate and high soil nutrient levels of this system. Total C pools in the aboveground biomass, litter, and organic soil horizon were greater under warming. Warmed plots contained from 272 to 319 g m−2 more C than plots under near‐ambient temperatures, corresponding to a 23–34% increase in ecosystem C.
Seasonal changes in the effects of free‐air CO2 enrichment (FACE) on growth, morphology and physiology of rice root at three levels of nitrogen fertilization
Authors: YANG LIANXIN , WANG YULONG , KOBAYASHI KAZUHIKO , ZHU JIANGUO , HUANG JIANYE , YANG HONGJIE , WANG YUNXIA , DONG GUICHUN , LIU GANG , HAN YONG , SHAN YUHUA , HU JIAN , ZHOU JUAN 
Published: April 2008

AbstractOver time, the relative effects of elevated [CO2] on the aboveground photosynthesis, growth and development of rice (Oryza sativa L.) are likely to be changed with increasing duration of CO2 exposure, but the resultant effects on rice belowground responses remain to be evaluated. To investigate the impacts of elevated [CO2] on seasonal changes in root growth, morphology and physiology of rice, a free‐air CO2 enrichment (FACE) experiment was performed at Wuxi, Jiangsu, China, in 2002–2003. A japonica cultivar with large panicle was exposed to two [CO2] (ambient [CO2], 370 μmol mol−1; elevated [CO2], 570 μmol mol−1) at three levels of nitrogen (N): low (LN, 15 g N m−2), medium (MN, 25 g N m−2) and high N (HN, 35 g N m−2). Elevated [CO2] increased cumulative root volume, root dry weight, adventitious root length and adventitious root number at all developmental stages by 25–71%, which was mainly associated with increased root growth rate during early growth period (EGP) and lower rate of root senescence during late growth period (LGP), while a slight inhibition of root growth rate occurred during middle growth period (MGP). For individual adventitious roots, elevated [CO2] increased average length, volume, diameter and dry weight early in the season, but the effects gradually disappeared in subsequent stages. Total surface area and active adsorption area per unit root dry weight reached their maxima 10 days earlier in FACE vs. ambient plants, but both of them together with root oxidation ability per unit root dry weight declined with elevated [CO2] during MGP and LGP, the decline being larger during MGP than LGP. The CO2‐induced decreases in specific root activities during MGP and LGP were associated with a larger amount of root accumulation during EGP and lower N concentration and higher C/N ratio in roots during MGP and LGP in FACE vs. ambient plants. The results suggest that most of the CO2‐induced increases in shoot growth of rice are similarly associated with increased root growth.
Predictive value of CASA parameters in IUI with frozen donor sperm
Authors: Freour Thomas , Jean Miguel , Mirallie Sophie , Langlois Marie‐Laure , Dubourdieu Sophie , Barriere Paul 
Published: April 2008

SummaryThe objective of this study was to determine if characteristics of sperm motion determined by computer‐aided semen analysis (CASA) after thawing and preparation on discontinuous gradient could predict pregnancy outcome after intrauterine insemination (IUI) from frozen donor sperm. A retrospective analysis of 100 non‐selected women undergoing 171 consecutive donor insemination cycles was conducted between January 2006 and April 2007. Semen samples from all donors were analysed after thawing and density gradient preparation. Women who became pregnant and those who did not were comparable in terms of age, ovarian stimulation regimen and indication of IUI with donor semen. Pregnancy rate per cycle was 21.8%, and pregnancy occurred after 2.5 IUI cycles on average. Motility parameters of sperm measured by CASA (VAP, VCL, VSL, LIN, STR, and ALH) and total spermatozoa concentration after preparation on discontinuous gradient showed no difference in both groups. Progressive and total motile spermatozoa concentration, as well as progressive and total motile percentages was significantly higher in pregnancy group. The receiver operating characteristic (ROC) curve analysis showed that total motile percentage >17% and motile concentration >0.9 × 106/mL best predicted pregnancy. In a multivariate analysis, only total motility percentage was able to predict pregnancy. Sperm motility parameters of frozen‐thawed prepared donor sperm obtained by CASA do not seem to predict pregnancy in IUI cycles. Total motile and progressive percentages and concentrations remain the best prognostic elements for pregnancy in IUI with donor semen.
PSP‐I/PSP‐II spermadhesin exert a decapacitation effect on highly extended boar spermatozoa
Authors: Caballero Ignacio , Vazquez Juan M. , Mayor Gloria M. , Almiñana Carmen , Calvete Juan J. , Sanz Libia , Roca Jordi , Martinez Emilio A. 
Published: April 2008

SummaryPSP‐I/PSP‐II heterodimer is a major protein of boar seminal plasma that is able to preserve, in vitro, the viability, motility and mitochondrial activity of highly‐extended boar spermatozoa. However, a relationship between the protective effects of the heterodimer and sperm capacitation is still unclear. The present study investigated the effect of the PSP‐I/PSP‐II (1.5 mg/mL) on membrane stability, intracellular calcium concentration ([Ca2+]I) and plasma membrane and acrosome integrity of highly extended boar spermatozoa. Boar spermatozoa were diluted to 1 × 106 spermatozoa/mL and incubated at 38 °C in Phosphate‐buffered saline (PBS) for 10, 30, 60, 120 and 300 min or in modified Tris‐buffered medium (mTBM) for 10, 20, 30, 60 and 120 min. After each incubation time, the membrane stability (using Merocyanine‐540/Yo‐Pro‐1), elevation of [Ca2+]I (using Fluo‐3‐AM/PI) and the sperm plasma membrane and acrosome integrity (using SYBR‐14/PI/PE‐PNA) were evaluated by flow cytometry. As expected, exposure of the spermatozoa to the PSP‐I/PSP‐II preserved the plasma membrane and acrosome integrity compared to non‐exposed spermatozoa in both media PBS and mTBM (p < .01). The evaluation of membrane stability showed no differences in the percentages of viable sperm with instable plasma membrane in the presence of the PSP‐I/PSP‐II compared to controls irrespective of the dilution media. The evaluation of the [Ca2+]I levels showed that while spermatozoa incubated in mTBM and exposed to PSP‐I/PSP‐II had lower [Ca2+]I than controls (39.08% vs. 47.97%, respectively; p < .05), no differences were observed in those samples incubated in PBS. However, a temporal evaluation of the samples showed that a similar proportion of live spermatozoa were able to achieve high levels of [Ca2+]I and membrane instability independent of the presence of PSP‐I/PSP‐II. In conclusion, PSP‐I/PSP‐II exert a non‐permanent decapacitation effect on highly extended boar spermatozoa that is related with a delay in the increase of [Ca2+]I levels.
The long strange trip of Borrelia burgdorferi outer‐surface protein C
Authors: Radolf Justin D. , Caimano Melissa J. 
Published: April 2008

Summary Borrelia burgdorferi must adapt physiologically to two markedly different host milieus and efficiently transit between its mammalian host and arthropod vector during tick feeding. Differential production of lipoproteins is essential for spirochaetes to survive, multiply and migrate within both hosts. Outer‐surface protein C (OspC), which is induced during the blood meal, is critical for transmission of Lyme disease spirochaetes by nymphal ticks. Its biological function is poorly understood, however, despite the fact that its crystal structure has been solved. Evidence has accumulated that OspC blocks clearance of spirochaetes following inoculation in skin, and it is thought to do so by facilitating evasion of innate immunity. The study by Liang and co‐workers in this edition of Molecular Microbiology extends this work by showing that OspC prevents early elimination and promotes dissemination. Surprisingly, they also show that unrelated borrelial outer‐surface lipoproteins can replace these functions in an ospC mutant. They propose that an abundance of lipoprotein(s) is needed to stabilize the borrelial outer membrane against innate defences. This provocative work clearly runs counter to prevailing orthodoxies of bacterial pathogenesis. It also points the way towards future studies that will clarify the ‘partially specific’ roles of this enigmatic molecule in Lyme disease pathogenesis.
Identification of antigenic proteins from Echinostoma caproni (Trematoda) recognized by mouse immunoglobulins M, A and G using an immunoproteomic approach
Authors: SOTILLO J. , VALERO L. , SÁNCHEZ DEL PINO M. M. , FRIED B. , ESTEBAN J. G. , MARCILLA A. , TOLEDO R. 
Published: April 2008

SUMMARY Antigenic proteins of Echinostoma caproni (Trematoda) against mouse IgM, IgA, IgG, IgG1 and IgG2a were investigated by immunoproteomics. Excretory/secretory products (ESP) of E. caproni separated by two‐dimensional (2D) gel electrophoresis were transferred to nitrocellulose membranes and probed with the different mouse immunoglobulin classes. A total of four proteins (enolase, 70 kDa heat‐shock protein (HSP‐70), actin and aldolase) were accurately identified. Enolase was recognized in eight different spots of which seven of them were detected in the expected molecular weight and were recognized by IgA, IgG or IgG and IgG1. Another spot identified as enolase at 72 kDa was only recognized by IgM. Digestion with N‐glycosidase F of the 72 kDa band rendered a polypeptide with an apparent molecular weight similar to that expected for enolase recognized by Western immunoblotting using anti‐enolase antibodies. This suggests that glycosylated forms of enolase may be involved in the early thymus‐independent responses against E. caproni. Early IgM responses were also generated by actin and the HSP‐70 which suggests that these proteins are exposed early to the host and may be of importance in the parasite establishment. The IgA responses also appear to be mediated by the HSP‐70 and aldolase which could be related with the close contact of these proteins with the host mucosal surface after secretion.
Photosynthesis in aquatic adventitious roots of the halophytic stem‐succulent Tecticornia pergranulata (formerly Halosarcia pergranulata)
Authors: RICH SARAH M. , LUDWIG MARTHA , COLMER TIMOTHY D. 
Published: April 2008

ABSTRACTIn flood‐tolerant species, a common response to inundation is growth of adventitious roots into the water column. The capacity for these roots to become photosynthetically active has received scant attention. The experiments presented here show the aquatic adventitious roots of the flood‐tolerant, halophytic stem‐succulent, Tecticornia pergranulata (subfamily Salicornioideae, Chenopodiaceae) are photosynthetic and quantify for the first time the photosynthetic capacity of aquatic roots for a terrestrial species. Fluorescence microscopy was used to determine the presence of chloroplasts within cells of aquatic roots. Net O2 production by excised aquatic roots, when underwater, was measured with varying light and CO2 regimes; the apparent maximum capacity (Pmax) for underwater net photosynthesis in aquatic roots was 0.45 µmol O2 m−2 s−1. The photosynthetic potential of these roots was supported by the immunolocalization of PsbA, the major protein of photosystem II, and ribulose‐1‐5‐bisphosphate carboxylase/oxygenase (Rubisco) in root protein extracts. Chlorophyllous aquatic roots of T. pergranulata are photosynthetically active, and such activity is a previously unrecognized source of O2, and potentially carbohydrates, in flooded and submerged plants.
Altered photosynthetic electron channelling into cyclic electron flow and nitrite assimilation in a mutant of ferredoxin:NADP(H) reductase
Authors: HANKE GUY THOMAS , ENDO TSUYOSHI , SATOH FUMIHIKO , HASE TOSHIHARU 
Published: April 2008

ABSTRACTThe mechanism by which plants regulate channelling of photosynthetically derived electrons into different areas of chloroplast metabolism remains obscure. Possible fates of such electrons include use in carbon assimilation, nitrogen assimilation and redox signalling pathways, or return to the plastoquinone pool through cyclic electron flow. In higher plants, these electrons are made accessible to stromal enzymes, or for cyclic electron flow, as reduced ferredoxin (Fd), or NADPH. We investigated how knockout of an Arabidopsis (Arabidopsis thaliana) ferredoxin:NADPH reductase (FNR) isoprotein and the loss of strong thylakoid binding by the remaining FNR in this mutant affected the channelling of photosynthetic electrons into NADPH‐ and Fd‐dependent metabolism. Chlorophyll fluorescence data show that these mutants have complex variation in cyclic electron flow, dependent on light conditions. Measurements of electron transport in isolated thylakoid and chloroplast systems demonstrated perturbed channelling to NADPH‐dependent carbon and Fd‐dependent nitrogen assimilating metabolism, with greater competition in the mutant. Moreover, mutants accumulate greater biomass than the wild type under low nitrate growth conditions, indicating that such altered chloroplast electron channelling has profound physiological effects. Taken together, our results demonstrate the integral role played by FNR isoform and location in the partitioning of photosynthetic reducing power.
Observations on the Macroscopic Anatomy of the Intestinal Tract and its Mesenteric Folds in the Pampas Deer (Ozotoceros bezoarticus, Linnaeus 1758)
Authors: Pérez W. , Clauss M. , Ungerfeld R. 
Published: April 2008

SummaryWe described the macroscopic anatomy of the intestines and their peritoneal folds of five adult pampas deer (Ozotoceros bezoarticus), a cervid species considered to ingest a high proportion of grass in its natural diet. The mean (±SD) body weight was 17 (±2) kg. The small intestine and the caecocolon measured 495 (±37) cm and 237 (±24) cm in length, respectively, with an average ratio (small intestine:caecocolon) of 1.9 (±0.1). The ascending colon had two and a half centripetal gyri, a central flexure and two centrifugal gyri. The spiral ansa, which was similar to an ellipse, was fixed to the whole left face of the mesenterium. Apart from the peritoneal folds described in the Nomina Anatomica Veterinaria, three additional, hitherto not described folds were found: a fold that fixed the caecum to the proximal ansa of the ascending colon, one that joined the terminal part of the proximal ansa to the last centrifugal gyrus of the spiral ansa of the ascending colon, and one that linked the ascending duodenum to the proximal ansa of the ascending colon. When compared with published data from other cervids of different feeding niches, it appears that, among cervids, the ratio of small intestine to the caecocolon length does not reflect the natural diet.
Gastric Submucosal Fat in Cats
Authors: Heng H. G. , Teoh W. T. , Sheikh Omar A. R. 
Published: April 2008

SummaryA previous study showed that a gastric intramural radiolucent band seen on radiographs and a gastric intramural hypoattenuating layer seen on computed tomography were due to the presence of gastric submucosal fat in a cat. There is no known prevalence and distribution pattern of this gastric submucosal fat in cats. This study was carried out to determine the prevalence and distribution pattern of submucosal fat in cat stomachs. Histologic examination of 41 cat stomachs was performed after scheduled killing of cats, obtained from animal shelters. The results revealed that submucosal fat was present in all stomachs. However, thickness and distribution pattern of the submucosal fat varied.
Stereological Assessment of the Epithelial Surface Area of the Ovine Palatine and Pharyngeal Tonsils
Authors: Casteleyn C. , Cornillie P. , Simoens P. , Van Den Broeck W. 
Published: April 2008

SummaryAlthough ovine tonsils play a major role in prion diseases, their morphology is poorly documented and morphometric data are sparse. Therefore, a stereological assessment of the surface area of the palatine and pharyngeal tonsils of five sheep was performed. The epithelial surface area of both tonsils is considerably increased by the presence of tonsillar crypts and folds. The mean epithelial surface area of the paired palatine tonsil was 7.14 cm² and that of the pharyngeal tonsil was 23.5 cm². In comparison with the paired palatine tonsil, the volume of the pharyngeal tonsil was almost two times larger, whilst its surface area was more than three times larger.
Sex Differences in Feeding Activity Results in Sexual Segregation of Feral Goats
Authors: Dunbar Robin I. M. , Shi Jianbin 
Published: April 2008

AbstractSexual segregation is common in ungulates. We show, in a high latitude population of feral goats where behavioural synchrony and fission rates have been shown to be the best explanation for segregation, that it is differences explicitly in the feeding time requirements of the two sexes (but not those for other activities) that best explains the variations in monthly frequencies of segregation. However, this effect is less marked during winter months when short day length forces the time budgets of the two sexes to converge. We argue that the various explanations for segregation can best be interpreted as separate factors in a multivariate model in which species‐ and habitat‐specific weightings influence the relative importance of these variables, and thus the likelihood that segregation will occur.
Mating Patterns of Red‐Eyed Treefrogs, Agalychnis callidryas and A. moreletii
Authors: Briggs Venetia S. 
Published: April 2008

AbstractDeviations from random mating in frogs are often explained by two different size‐based patterns. The large‐male mating advantage predicts that males found in amplexus with females will be larger on average than non‐amplectant males, whereas size‐assortative mating predicts that males and females found in amplexus will maintain an optimal size ratio. Both these pairing patterns are consistent with a female mating preference for larger males, or for males of a given size relative to the choosy female. I examined pairing patterns of two species of Neotropical hylids, Agalychnis callidryas and A. moreletii for three consecutive breeding seasons in Belize, Central America to evaluate whether mating behavior was influenced by either a large‐male mating advantage or size‐assortative mating. For each species, I compared size traits between amplectant and non‐amplectant males, and within amplectant pairs, and I quantified fertilization success for each amplectant pair. For both species I found evidence of deviations from random mating by size, but the nature of the deviations varied between species and among years. The proportion of eggs fertilized was consistently high among years for both species and there was no relationship between fertilization success and the size ratio of amplectant pairs. These data are consistent with female mate preference, but a role for male–male competition cannot be excluded. My findings suggest that mating patterns may be density‐dependent and that the nature and intensity of sexual selection may be increased by extreme environmental conditions.