bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced Abscisic Acid-Mediated Responses innia1nia2noa1-2Triple Mutant Impaired in NIA/NR- and AtNOA1-Dependent Nitric Oxide Biosynthesis in Arabidopsis
Authors: Lozano-Juste Jorge , Leoݩn Joseݩ 
Published: December 2009

AbstractNitric oxide (NO) regulates a wide range of plant processes from development to environmental adaptation. Despite its reported regulatory functions, it remains unclear how NO is synthesized in plants. We have generated a triple nia1nia2noa1-2 mutant that is impaired in nitrate reductase (NIA/NR)- and Nitric Oxide-Associated1 (AtNOA1)-mediated NO biosynthetic pathways. NO content in roots of nia1nia2 and noa1-2 plants was lower than in wild-type plants and below the detection limit in nia1nia2noa1-2 plants. NIA/NR- and AtNOA1-mediated biosynthesis of NO were thus active and responsible for most of the NO production in Arabidopsis (Arabidopsis thaliana). The nia1nia2noa1-2 plants displayed reduced size, fertility, and seed germination potential but increased dormancy and resistance to water deficit. The increasing deficiency in NO of nia1nia2, noa1-2, and nia1nia2noa1-2 plants correlated with increased seed dormancy, hypersensitivity to abscisic acid (ABA) in seed germination and establishment, as well as dehydration resistance. In nia1nia2noa1-2 plants, enhanced drought tolerance was due to a very efficient stomata closure and inhibition of opening by ABA, thus uncoupling NO from ABA-triggered responses in NO-deficient guard cells. The NO-deficient mutants in NIA/NR- and AtNOA1-mediated pathways in combination with the triple mutant will be useful tools to functionally characterize the role of NO and the contribution of both biosynthetic pathways in regulating plant development and defense.
The Role of Casein Kinase II in Flowering Time Regulation Has Diversified during Evolution
Authors: Ogiso Eri , Takahashi Yuji , Sasaki Takuji , Yano Masahiro , Izawa Takeshi 
Published: December 2009

Abstract
Casein kinase II (CK2) is a protein kinase with an evolutionarily conserved function as a circadian clock component in several organisms, including the long-day plant Arabidopsis (Arabidopsis thaliana). The circadian clock component CIRCADIAN CLOCK ASSOCIATED1 (CCA1) is a CK2 target in Arabidopsis, where it influences photoperiodic flowering. In rice (Oryza sativa), a short-day plant, Heading date6 (Hd6) encodes a CK2α subunit that delays flowering time under long-day conditions. Here, we demonstrate that control of flowering time in rice by the Hd6 CK2α subunit requires a functional Hd1 gene (an Arabidopsis CONSTANS ortholog) and is independent of the circadian clock mechanism. Our findings from overexpressing the dominant-negative CK2 allele in rice support the independence of CK2 function from the circadian clock. This lack of control of the circadian clock by Hd6 CK2α might be due to the presence of glutamate in OsLHY (a CCA1 ortholog in rice) instead of the serine at the corresponding CK2 target site in CCA1. However, this glutamate is critical for the control of the OsPRR1 gene (a rice ortholog of the Arabidopsis TOC1/PRR1 gene) by OsLHY for regulation of the circadian clock. We also demonstrated that the other conserved CK2 target sites in OsLHY conferred robust rhythmic expression of OsLHY-LUC under diurnal conditions. These findings imply that the role of CK2 in flowering-time regulation in higher plants has diversified during evolution.
Jasmonate-Dependent and -Independent Pathways Mediate Specific Effects of Solar Ultraviolet B Radiation on Leaf Phenolics and Antiherbivore Defense
Authors: Demkura Patricia V. , Abdala Guillermina , Baldwin Ian T. , Ballareݩ Carlos L. 
Published: December 2009

Abstract
Ultraviolet B (UV-B) radiation, a very small fraction of the daylight spectrum, elicits changes in plant secondary metabolism that have large effects on plant-insect interactions. The signal transduction pathways that mediate these specific effects of solar UV-B are not known. We examined the role of jasmonate signaling by measuring responses to UV-B in wild-type and transgenic jasmonate-deficient Nicotiana attenuata plants in which a lipoxygenase gene (NaLOX3) was silenced (as-lox). In wild-type plants, UV-B failed to elicit the accumulation of jasmonic acid (JA) or the bioactive JA-isoleucine conjugate but amplified the response of jasmonate-inducible genes, such as trypsin proteinase inhibitor (TPI), to wounding and methyl jasmonate, and increased the accumulation of several phenylpropanoid derivatives. Some of these phenolic responses (accumulation of caffeoyl-polyamine conjugates) were completely lacking in as-lox plants, whereas others (accumulation of rutin and chlorogenic acid) were similar in both genotypes. In open field conditions, as-lox plants received more insect damage than wild-type plants, as expected, but the dramatic increase in resistance to herbivory elicited by UV-B exposure, which was highly significant in wild-type plants, did not occur in as-lox plants. We conclude that solar UV-B (1) uses jasmonate-dependent and -independent pathways in the elicitation of phenolic compounds, and (2) increases sensitivity to jasmonates, leading to enhanced expression of wound-response genes (TPI). The lack of UV-B-induced antiherbivore protection in as-lox plants suggests that jasmonate signaling plays a central role in the mechanisms by which solar UV-B increases resistance to insect herbivores in the field.
Knockdown of the Symbiotic Sucrose Synthase MtSucS1 Affects Arbuscule Maturation and Maintenance in Mycorrhizal Roots of Medicago truncatula
Authors: Baier Markus Christian , Keck Matthias , Goݶdde Victoria , Niehaus Karsten , Kuݶster Helge , Hohnjec Natalija 
Published: December 2009

Abstract
The relevance of the symbiosis-induced Medicago truncatula sucrose synthase gene MtSucS1 for an efficient arbuscular mycorrhiza (AM) was studied using two independent antisense lines that displayed up to 10-fold reduced SucS1 levels in roots. Mycorrhizal MtSucS1-reduced lines exhibited an overall stunted aboveground growth under inorganic phosphorus limitation. Apart from a reduced plant height, shoot weight, and leaf development, a delayed flowering, resulting in a lower seed yield, was observed. In addition, the root-to-shoot and root weight ratios increased significantly. Gene expression studies demonstrated a major reversion of AM-associated transcription, exhibiting a significant repression of well-known plant AM marker and mycosymbiont genes, together indicating a diminished AM fungus colonization of MtSucS1-antisense lines. Concomitantly, gas chromatography-mass spectrometry-based metabolite profiling revealed that mycorrhizal MtSucS1-reduced lines were affected in important nodes of the carbon, nitrogen, and phosphorus metabolism, accentuating a physiological significance of MtSucS1 for AM. In fact, antisensing MtSucS1 provoked an impaired fungal colonization within the less abundant infected regions, evident from strongly reduced frequencies of internal hyphae, vesicles, and arbuscules. Moreover, arbuscules were early senescing, accompanied with a reduced development of mature arbuscules. This defective mycorrhiza status correlated with reduced phosphorus and nitrogen levels and was proportional to the extent of MtSucS1 knockdown. Together, our results point to an important role for MtSucS1 in the establishment and maintenance of arbuscules in the AM symbiosis.
Distribution, density and impact of invasive plants in Lake Nakuru National Park, Kenya
Authors: Ng’weno Caroline C. , Mwasi Shem M. , Kairu Jim K. 
Published: December 2009

AbstractInvasive plants have invaded swathes of grasslands in Lake Nakuru National Park thus necessitating the Park management to institute measures to control them. Despite this, information on the status and impact of invasive plants in these grasslands is lacking. Six grassland types were identified and assigned random numbers. Five study sites were then randomly selected from each grassland type. The Point‐Centre Quarter method was used to determine the distribution and density of seven major invasive plants, whilst their impact was assessed by comparing biomass and crude protein content of important forage grasses in invaded and noninvaded grasslands. Results show that the distribution of invasive plants did not differ among the grasslands (F5, 30 = 1.47, P = 0.229) but their densities differed among the plants (F6, 30 = 20.99, P < 0.001). The mean biomass in invaded and noninvaded grasslands (22 g m−2 versus 37.2 g m−2) was significantly different (t‐test, P < 0.05), while crude protein content of grasses in invaded (7.73, % DM) and noninvaded (9.3, % DM) patches was not significantly different (t‐test; P > 0.05). Our results suggest that invasive plants lower grass production and hence might reduce food availability to grazers.
Testis response to low doses of cadmium in Wistar rats
Authors: De Souza Predes Fabricia , Diamante Maria Aparecida S. , Dolder Heidi 
Published: December 2009

SummaryAlthough it is well known that cadmium (Cd) causes adverse effects on male rat reproductive organs, few studies have quantified alterations caused by its low doses. Quantification of these alterations, especially in the testis, was measured using morphometry. A single dose of cadmium chloride (1 or 1.2 mg/kg BW) was injected i.p. in adult rats, killed after 7 or 56 days. The lower dose caused slight alterations as measured by morphometrical analysis. The higher dose caused significant reduction in testis and epididymis weight, gonadossomatic index and length of seminiferous tubule (ST) after 7 and 56 days. Cadmium significantly reduced the ST diameter after 56 days. Decreased volume density of ST, after 7 and 56 days, was accompanied by an increase in interstitium volume density. The damage caused by the dose of 1.2 mg/kg can be clearly observed with light microscope. After 7 days, the tubule lumens were filled with degenerated germ cells and multinucleated spermatid aggregates. Vacuolization of the seminiferous epithelium was also observed. After 56 days, increased damage resulted in vacuolated ST, consisting only of Sertoli cells. Scanning electron microscopy examination of the testis showed that, in the group cadmium treated (1.2 mg/kg) and killed after 56 days, the interstitial tissue presents a compact and fibrous appearance with absence of fenestrae. The seminiferous epithelium height diminished and the absence of spermatozoa can be noted. The results show that a very small difference of Cd dose causes a sudden increase in testicular damage, apparently overpowering this tissue’s natural defences.
Induction of the ferritin gene (ftnA) ofEscherichia coliby Fe2+–Fur is mediated by reversal of H‐NS silencing and is RyhB independent
Authors: Nandal Anjali , Huggins Cerys C. O. , Woodhall Mark R. , McHugh Jonathan , Rodríguez‐Quiñones Francisco , Quail Michael A. , Guest John R. , Andrews Simon C. 
Published: December 2009

SummaryFtnA is the major iron‐storage protein ofEscherichia coliaccounting for ≤50% of total cellular iron. The FtnA gene (ftnA) is induced by iron in an Fe2+–Fur‐dependent fashion. This effect is reportedly mediated by RyhB, the Fe2+–Fur‐repressed, small, regulatory RNA. However, results presented here show thatftnAiron induction is independent of RyhB and instead involves direct interaction of Fe2+–Fur with an ‘extended’ Fur binding site (containing five tandem Fur boxes) located upstream (−83) of theftnApromoter. In addition, H‐NS acts as a direct repressor offtnAtranscription by binding at multiple sites (I–VI) within, and upstream of, theftnApromoter. Fur directly competes with H‐NS binding at upstream sites (II–IV) and consequently displaces H‐NS from theftnApromoter (sites V–VI) which in turn leads to derepression offtnAtranscription. It is proposed that H‐NS binding within theftnApromoter is facilitated by H‐NS occupation of the upstream sites through H‐NS oligomerization‐induced DNA looping. Consequently, Fur displacement of H‐NS from the upstream sites prevents cooperative H‐NS binding at the downstream sites within the promoter, thus allowing access to RNA polymerase. This direct activation offtnAtranscription by Fe2+–Fur through H‐NS antisilencing represents a new mechanism for iron‐induced gene expression.
Horizontally acquired homologues of the nucleoid‐associated protein H‐NS: implications for gene regulation
Authors: Dorman Charles J. 
Published: December 2009

SummaryH‐NS is one of the most intensively studied members of the family of bacterial nucleoid‐associated proteins. It is a DNA‐binding protein with a preference for A+T‐rich DNA sequences, and it represses the transcription of hundreds of genes in Gram‐negative bacteria, including pathogens. In most cases where the issue has been investigated, the repressive activity of H‐NS is opposed by the intervention of an antagonistically acting DNA‐binding protein, a remodelling of local DNA structure, or a combination of these two. H‐NS activity can also be modulated by protein–protein interaction with members of the Hha/YdgT protein family, molecules that share partial amino acid sequence similarity to the oligomerization domain of H‐NS. Of particular interest is the ability of H‐NS to interact with the full‐length paralogue StpA or full‐length orthologues that have been acquired by horizontal DNA transfer. In this issue of Molecular Microbiology, Müller et al. describe the H‐NS orthologue Hfp and present evidence that in bacteria that acquire Hfp the range of activities of H‐NS is modified with important implications for the physiology of the bacterium.
Surgical history of ancient China: part 1
Authors: Fu Louis 
Published: December 2009

AbstractAlthough surgery was an accepted and quite proficient craft very early on in Chinese history, it has deteriorated through the ages. Despite the fact that anaesthetic agents in major surgery were employed during the third century, Chinese surgery is conspicuous by its stagnation. Reverence for the dead, filial piety, abhorrence of shedding blood and other conservative attitudes make it impossible for any accurate knowledge of the human anatomy and physiology, without which surgery cannot progress. This article surveys some highlights in the history of surgery in ancient China and examines the factors responsible for its decline. The second concluding part deals with orthopaedics.
Fijian seasonal scourge of mango tree falls
Authors: Gupta Anuj , Reeves Ben 
Published: December 2009

AbstractBackground:  Mango tree falls are a frequent presentation at any health facility in the South Pacific. This study aims to identify (i) the number of admissions because of falls from mango trees; (ii) epidemiology; (iii) seasonal trend; (iv) injury profile; and (v) hospital care provided.Methods:  Retrospective case review on all mango tree falls related injuries resulting in admissions at the Lautoka Hospital, Fiji during a 1‐year period (2007). Patient records were analysed to identify specific injury patterns such as upper/lower limb fractures, spinal cord injury and head injury, caused by mango tree falls.Results:  Thirty‐nine cases were identified. Eighty‐two percent (n= 32) of the falls occurred in the mango season (June–November). Seventy‐two percent (n= 28) of the patients were males and 28% (n= 11) were females. Seventy‐six percent were aged 5–13 and only 21% were adults. Also, 77% (n= 30) of the patients were ethnic Fijians and 23% (n= 9) were Fijian‐Indians. Sixty‐four percent (n= 25) had closed fractures and 17% (n= 7) had open fractures. Fifty‐six percent (n= 22) of the fractures were of the fore arm. There were two cases of spinal cord injury, four cases of head injury, one ICU admission and one death. Average hospital stay was 7.56 days.Conclusion:  All these injuries were recreational and the majority in the urban setting. They were all avoidable.
Famous discoveries by medical students
Authors: Stringer Mark D. , Ahmadi Omid 
Published: December 2009

AbstractHeparin, insulin, the sinoatrial node and ether anaesthesia are just some of the major discoveries made by medical students, all of which have had a huge impact on the practice of surgery. This paper explores the breadth and depth of some of these talented individuals and their extraordinary contributions to medicine. While some continued to enjoy brilliant careers, others became embroiled in damaging disputes about priority or were overtaken by illness or personal problems. Regardless of their fate, their contributions are a potent reminder of what can be achieved by gifted and determined medical students undertaking a period of basic scientific or clinical research.
Evaluating anatomical research in surgery: a prospective comparison of cadaveric and living anatomical studies of the abdominal wall
Authors: Rozen Warren M. , Chubb Daniel , Stella Damien L. , Taylor G. Ian , Ashton Mark W. 
Published: December 2009

AbstractBackground:  Cadaveric research has widely influenced our understanding of clinical anatomy. However, while many soft‐tissue structures remain quiescent after death, other tissues, such as viscera, undergo structural and functional changes that may influence their use in predicting living anatomy. In particular, our understanding of vascular anatomy has been based upon cadaveric studies, in which vascular tone and flow do not match the living situation.Methods:  An angiographic analysis of the abdominal wall vasculature was performed using plain film and computed tomography angiography in 60 cadaveric hemi‐abdominal walls (from 31 cadavers) and 140 living hemi‐abdominal walls (in 70 patients). The deep inferior epigastric artery (DIEA) and all of its perforating branches larger than 0.5 mm were analysed for number, calibre and location.Results:  Both large, named vessels and small calibre vessels show marked differences between living anatomy and cadaveric specimens. The DIEA was of larger diameter (4.2 mm versus 3.1 mm, P < 0.01) and had more detectable branches in the cadaveric specimens. Perforators were of greater calibre (diameter 1.5 mm versus 0.8 mm, P < 0.01) and were more plentiful (16 versus 6, P < 0.01) in cadaveric specimens. However, the location of individual vessels was similar.Conclusions:  Cadaveric anatomy displays marked differences to in vivo anatomy, with the absence of living vascular dynamics affecting vessel diameters in cadaveric specimens. Blood vessels are of greater measurable calibre in cadaveric specimens than in the living. Consequently, cadaveric anatomy should be interpreted with consideration of post‐mortem changes, while living anatomical studies, particularly with the use of imaging technologies, should be embraced in anatomical research.
Distinct contributions of the amygdala and hippocampus to fear expression
Authors: Chudasama Yogita , Izquierdo Alicia , Murray Elisabeth A. 
Published: December 2009

AbstractThe present study attempted to distinguish the independent contributions of the amygdala and hippocampus to fear expression. Rhesus monkeys (Macaca mulatta) with bilateral excitotoxic amygdala lesions (n = 4), bilateral excitotoxic hippocampal lesions (n = 8) and unoperated controls (n = 9) were allowed to reach over a neutral junk object or fear‐provoking stimulus (i.e., a rubber snake or a jumping rubber spider) to retrieve a food reward. Monkeys were exposed to each stimulus for 30 s. On each trial we recorded the monkey’s latency to retrieve the food reward and scored their whole‐body reactions to the object. Confirming previous work we found that, relative to controls, both operated groups showed shorter food‐retrieval latencies and exhibited fewer defensive and more approach behaviors when exposed to the fear‐provoking stimuli. However, only monkeys with amygdala lesions showed an abnormal, excessive visual interest in the snake and spider. By contrast, monkeys with hippocampal lesions displayed behaviors that were unrelated to the presence of the fear stimuli, thereby indicating a lack of interest in, and emotional reactivity towards, the snake and spider. These data show that the hippocampus and amygdala contribute independently to the overall expression of defensive responses.
Prostaglandin E receptor EP1 enhances GABA‐mediated inhibition of dopaminergic neurons in the substantia nigra pars compacta and regulates dopamine level in the dorsal striatum
Authors: Tanaka Yasuhiro , Furuyashiki Tomoyuki , Momiyama Toshihiko , Namba Hisaaki , Mizoguchi Akira , Mitsumori Tomoyuki , Kayahara Tetsuro , Shichi Hitoshi , Kimura Kazushi , Matsuoka Toshiyuki , Nawa Hiroyuki , Narumiya Shuh 
Published: December 2009

AbstractDopamine (DA) is a neuromodulator that is critical for sensory‐motor, cognitive and emotional functions. We previously found that mice lacking prostaglandin E receptor EP1 showed impulsive emotional behaviors accompanied by enhanced DA turnover in the frontal cortex and striatum. Given that these behavioral phenotypes were corrected by DA receptor antagonists, we hypothesized that EP1 deficiency causes a hyperdopaminergic state for its behavioral phenotype. Here we tested this hypothesis by examining the EP1 action in the nigrostriatal dopaminergic system. We first used microdialysis and found an elevated extracellular DA level in the dorsal striatum of EP1‐deficient mice compared with wild‐type mice. Despite the EP1 expression in the striatum, neither deficiency nor activation of EP1 altered the intrastriatal control for DA release, uptake or degradation. Immunohistochemistry revealed punctate EP1 signals apposed with dopaminergic neurons in the substantia nigra pars compacta (SNc). Many EP1 signals were colocalized with a marker for GABAergic synapses. Further, an EP1 agonist enhanced GABAA‐mediated inhibitory inputs to SNc dopaminergic neurons in midbrain slices. Therefore, the prostaglandin E2‐EP1 signaling directly enhances GABAergic inputs to SNc dopaminergic neurons. The lack of this EP1 action may lead to a hyperdopaminergic state of EP1‐deficient mice.
Functional correlates of activity in neurons projecting from the lamina terminalis to the ventrolateral periaqueductal gray
Authors: Uschakov Aaron , McGinty Dennis , Szymusiak Ronald , McKinley Michael J. 
Published: December 2009

AbstractThe lamina terminalis (LT) consists of the organum vasculosum of the LT (OVLT), the median preoptic nucleus (MnPO) and the subfornical organ (SFO). All subdivisions of the LT project to the ventrolateral periaqueductal gray (vlPAG). The LT and the vlPAG are implicated in several homeostatic and behavioral functions, including body fluid homeostasis, thermoregulation and the regulation of sleep and waking. By combining visualization of c‐Fos protein and retrograde neuroanatomical tracer we have examined the functional correlates of LT‐vlPAG projection neurons. Rats were injected with retrograde tracer into the vlPAG and, following a 1‐week recovery period, they were subjected to either hypertonic saline administration (0.5 m NaCl, 1 mL/100 g i.p.), 24‐h water deprivation, isoproterenol administration (increases circulating angiotensin II; 50 μg/kg s.c.), heat exposure (39°C for 60 min) or permitted 180 min spontaneous sleep. Retrogradely labeled neurons from the vlPAG and double‐labelled neurons were then identified and quantified throughout the LT. OVLT‐vlPAG projection neurons were most responsive to hypertonic saline and water deprivation. SFO‐vlPAG projection neurons were most active following isoproterenol administration, and MnPO‐vlPAG projection neurons displayed significantly more Fos immunostaining following water deprivation, heat exposure and sleep. These results support the existence of functional subdivisions of LT‐vlPAG‐projecting neurons, and indicate three patterns of activity that correspond to thermal and sleep wake regulation, osmotic or hormonal stimuli.