265 research outputs found
Three minimum tile paths from bacterial artificial chromosome libraries of the soybean (Glycine max cv. 'Forrest'): tools for structural and functional genomics
BACKGROUND: The creation of minimally redundant tile paths (hereafter MTP) from contiguous sets of overlapping clones (hereafter contigs) in physical maps is a critical step for structural and functional genomics. Build 4 of the physical map of soybean (Glycine max L. Merr. cv. 'Forrest') showed the 1 Gbp haploid genome was composed of 0.7 Gbp diploid, 0.1 Gbp tetraploid and 0.2 Gbp octoploid regions. Therefore, the size of the unique genome was about 0.8 Gbp. The aim here was to create MTP sub-libraries from the soybean cv. Forrest physical map builds 2 to 4. RESULTS: The first MTP, named MTP2, was 14,208 clones (of mean insert size 140 kbp) picked from the 5,597 contigs of build 2. MTP2 was constructed from three BAC libraries (BamHI (B), HindIII (H) and EcoRI (E) inserts). MTP2 encompassed the contigs of build 3 that derived from build 2 by a series of contig merges. MTP2 encompassed 2 Gbp compared to the soybean haploid genome of 1 Gbp and does not distinguish regions by ploidy. The second and third MTPs, called MTP4BH and MTP4E, were each based on build 4. Each was semi-automatically selected from 2,854 contigs. MTP4BH was 4,608 B and H insert clones of mean size 173 kbp in the large (27.6 kbp) T-DNA vector pCLD04541. MTP4BH was suitable for plant transformation and functional genomics. MTP4E was 4,608 BAC clones with large inserts (mean 175 kbp) in the small (7.5 kbp) pECBAC1 vector. MTP4E was suitable for DNA sequencing. MTP4BH and MTP4E clones each encompassed about 0.8 Gbp, the 0.7 Gbp diploid regions and 0.05 Gbp each from the tetraploid and octoploid regions. MTP2 and MTP4BH were used for BAC-end sequencing, EST integration, micro-satellite integration into the physical map and high information content fingerprinting. MTP4E will be used for genome sequence by pooled genomic clone index. CONCLUSION: Each MTP and associated BES will be useful to deconvolute and ultimately finish the whole genome shotgun sequence of soybean
Effects of acute fatigue on the volitional and magnetically-evoked electromechanical delay of the knee flexors in males and females
Neuromuscular performance capabilities, including those measured by evoked responses, may be adversely affected by fatigue; however, the capability of the neuromuscular system to initiate muscle force rapidly under these circumstances is yet to be established. Sex-differences in the acute responses of neuromuscular performance to exercise stress may be linked to evidence that females are much more vulnerable to ACL injury than males. Optimal functioning of the knee flexors is paramount to the dynamic stabilisation of the knee joint, therefore the aim of this investigation was to examine the effects of acute maximal intensity fatiguing exercise on the voluntary and magnetically-evoked electromechanical delay in the knee flexors of males and females. Knee flexor volitional and magnetically-evoked neuromuscular performance was assessed in seven male and nine females prior to and immediately after: (i) an intervention condition comprising a fatigue trial of 30-seconds maximal static exercise of the knee flexors, (ii) a control condition consisting of no exercise. The results showed that the fatigue intervention was associated with a substantive reduction in volitional peak force (PFV) that was greater in males compared to females (15.0%, 10.2%, respectively, p < 0.01) and impairment to volitional electromechanical delay (EMDV) in females exclusively (19.3%, p < 0.05). Similar improvements in magnetically-evoked electromechanical delay in males and females following fatigue (21%, p < 0.001), however, may suggest a vital facilitatory mechanism to overcome the effects of impaired voluntary capabilities, and a faster neuromuscular response that can be deployed during critical times to protect the joint system
Separate loci underlie resistance to root infection and leaf scorch during soybean sudden death syndrome
Soybean [Glycine max (L.) Merr.] cultivars show differences in their resistance to both the leaf scorch and root rot of sudden death syndrome (SDS). The syndrome is caused by root colonization by Fusarium virguliforme (ex. F. solani f. sp. glycines). Root susceptibility combined with reduced leaf scorch resistance has been associated with resistance to Heterodera glycines HG Type 1.3.6.7 (race 14) of the soybean cyst nematode (SCN). In contrast, the rhg1 locus underlying resistance to Hg Type 0 was found clustered with three loci for resistance to SDS leaf scorch and one for root infection. The aims of this study were to compare the inheritance of resistance to leaf scorch and root infection in a population that segregated for resistance to SCN and to identify the underlying quantitative trait loci (QTL). “Hartwig”, a cultivar partially resistant to SDS leaf scorch, F. virguliforme root infection and SCN HG Type 1.3.6.7 was crossed with the partially susceptible cultivar “Flyer”. Ninety-two F5-derived recombinant inbred lines and 144 markers were used for map development. Four QTL found in earlier studies were confirmed. One contributed resistance to leaf scorch on linkage group (LG) C2 (Satt277; P = 0.004, R 2 = 15%). Two on LG G underlay root infection at R8 (Satt038; P = 0.0001 R 2 = 28.1%; Satt115; P = 0.003, R 2 = 12.9%). The marker Satt038 was linked to rhg1 underlying resistance to SCN Hg Type 0. The fourth QTL was on LG D2 underlying resistance to root infection at R6 (Satt574; P = 0.001, R 2 = 10%). That QTL was in an interval previously associated with resistance to both SDS leaf scorch and SCN Hg Type 1.3.6.7. The QTL showed repulsion linkage with resistance to SCN that may explain the relative susceptibility to SDS of some SCN resistant cultivars. One additional QTL was discovered on LG G underlying resistance to SDS leaf scorch measured by disease index (Satt130; P = 0.003, R 2 = 13%). The loci and markers will provide tagged alleles with which to improve the breeding of cultivars combining resistances to SDS leaf scorch, root infection and SCN HG Type 1.3.6.7
Dengue Virus Infection and Virus-Specific HLA-A2 Restricted Immune Responses in Humanized NOD-scid IL2rγnull Mice
BACKGROUND:The lack of a suitable animal model to study viral and immunological mechanisms of human dengue disease has been a deterrent to dengue research. METHODOLOGY/PRINCIPAL FINDINGS:We sought to establish an animal model for dengue virus (DENV) infection and immunity using non-obese diabetic/severe combined immunodeficiency interleukin-2 receptor gamma-chain knockout (NOD-scid IL2rgamma(null)) mice engrafted with human hematopoietic stem cells. Human CD45(+) cells in the bone marrow of engrafted mice were susceptible to in vitro infection using low passage clinical and established strains of DENV. Engrafted mice were infected with DENV type 2 by different routes and at multiple time points post infection, we detected DENV antigen and RNA in the sera, bone marrow, spleen and liver of infected engrafted mice. Anti-dengue IgM antibodies directed against the envelope protein of DENV peaked in the sera of mice at 1 week post infection. Human T cells that developed following engraftment of HLA-A2 transgenic NOD-scid IL2rgamma(null) mice with HLA-A2(+) human cord blood hematopoietic stem cells, were able to secrete IFN-gamma, IL-2 and TNF-alpha in response to stimulation with three previously identified A2 restricted dengue peptides NS4b 2353((111-119)), NS4b 2423((181-189)), and NS4a 2148((56-64)). CONCLUSIONS/SIGNIFICANCE:This is the first study to demonstrate infection of human cells and functional DENV-specific T cell responses in DENV-infected humanized mice. Overall, these mice should be a valuable tool to study the role of prior immunity on subsequent DENV infections
The effects of a strength and neuromuscular exercise programme for the lower extremity on knee load, pain and function in obese children and adolescents: study protocol for a randomised controlled trial
The Role of Individual Variables, Organizational Variables and Moral Intensity Dimensions in Libyan Management Accountants’ Ethical Decision Making
This study investigates the association of a broad set of variables with the ethical decision making of management accountants in Libya. Adopting a cross-sectional methodology, a questionnaire including four different ethical scenarios was used to gather data from 229 participants. For each scenario, ethical decision making was examined in terms of the recognition, judgment and intention stages of Rest’s model. A significant relationship was found between ethical recognition and ethical judgment and also between ethical judgment and ethical intention, but ethical recognition did not significantly predict ethical intention—thus providing support for Rest’s model. Organizational variables, age and educational level yielded few significant results. The lack of significance for codes of ethics might reflect their relative lack of development in Libya, in which case Libyan companies should pay attention to their content and how they are supported, especially in the light of the under-development of the accounting profession in Libya. Few significant results were also found for gender, but where they were found, males showed more ethical characteristics than females. This unusual result reinforces the dangers of gender stereotyping in business. Personal moral philosophy and moral intensity dimensions were generally found to be significant predictors of the three stages of ethical decision making studied. One implication of this is to give more attention to ethics in accounting education, making the connections between accounting practice and (in Libya) Islam. Overall, this study not only adds to the available empirical evidence on factors affecting ethical decision making, notably examining three stages of Rest’s model, but also offers rare insights into the ethical views of practising management accountants and provides a benchmark for future studies of ethical decision making in Muslim majority countries and other parts of the developing world
Humanized Mouse Model of Ovarian Cancer Recapitulates Patient Solid Tumor Progression, Ascites Formation, and Metastasis
Ovarian cancer is the most common cause of death from gynecological cancer. Understanding the biology of this disease, particularly how tumor-associated lymphocytes and fibroblasts contribute to the progression and metastasis of the tumor, has been impeded by the lack of a suitable tumor xenograft model. We report a simple and reproducible system in which the tumor and tumor stroma are successfully engrafted into NOD-scid IL2Rγnull (NSG) mice. This is achieved by injecting tumor cell aggregates derived from fresh ovarian tumor biopsy tissues (including tumor cells, and tumor-associated lymphocytes and fibroblasts) i.p. into NSG mice. Tumor progression in these mice closely parallels many of the events that are observed in ovarian cancer patients. Tumors establish in the omentum, ovaries, liver, spleen, uterus, and pancreas. Tumor growth is initially very slow and progressive within the peritoneal cavity with an ultimate development of tumor ascites, spontaneous metastasis to the lung, increasing serum and ascites levels of CA125, and the retention of tumor-associated human fibroblasts and lymphocytes that remain functional and responsive to cytokines for prolonged periods. With this model one will be able to determine how fibroblasts and lymphocytes within the tumor microenvironment may contribute to tumor growth and metastasis, and will make it possible to evaluate the efficacy of therapies that are designed to target these cells in the tumor stroma
Can Thermoclines Be a Cue to Prey Distribution for Marine Top Predators? A Case Study with Little Penguins
The use of top predators as bio-platforms is a modern approach to understanding how physical changes in the environment may influence their foraging success. This study examined if the presence of thermoclines could be a reliable signal of resource availability for a marine top predator, the little penguin (Eudyptula minor). We studied weekly foraging activity of 43 breeding individual penguins equipped with accelerometers. These loggers also recorded water temperature, which we used to detect changes in thermal characteristics of their foraging zone over 5 weeks during the penguin’s guard phase. Data showed the thermocline was detected in the first 3 weeks of the study, which coincided with higher foraging efficiency. When a thermocline was not detected in the last two weeks, foraging efficiency decreased as well. We suggest that thermoclines can represent temporary markers of enhanced food availability for this top-predator to which they must optimally adjust their breeding cycle
Proposed Role for COUP-TFII in Regulating Fetal Leydig Cell Steroidogenesis, Perturbation of Which Leads to Masculinization Disorders in Rodents
Reproductive disorders that are common/increasing in prevalence in human males may arise because of deficient androgen production/action during a fetal ‘masculinization programming window’. We identify a potentially important role for Chicken Ovalbumin Upstream Promoter-Transcription Factor II (COUP-TFII) in Leydig cell (LC) steroidogenesis that may partly explain this. In rats, fetal LC size and intratesticular testosterone (ITT) increased ∼3-fold between e15.5-e21.5 which associated with a progressive decrease in the percentage of LC expressing COUP-TFII. Exposure of fetuses to dibutyl phthalate (DBP), which induces masculinization disorders, dose-dependently prevented the age-related decrease in LC COUP-TFII expression and the normal increases in LC size and ITT. We show that nuclear COUP-TFII expression in fetal rat LC relates inversely to LC expression of steroidogenic factor-1 (SF-1)-dependent genes (StAR, Cyp11a1, Cyp17a1) with overlapping binding sites for SF-1 and COUP-TFII in their promoter regions, but does not affect an SF-1 dependent LC gene (3β-HSD) without overlapping sites. We also show that once COUP-TFII expression in LC has switched off, it is re-induced by DBP exposure, coincident with suppression of ITT. Furthermore, other treatments that reduce fetal ITT in rats (dexamethasone, diethylstilbestrol (DES)) also maintain/induce LC nuclear expression of COUP-TFII. In contrast to rats, in mice DBP neither causes persistence of fetal LC COUP-TFII nor reduces ITT, whereas DES-exposure of mice maintains COUP-TFII expression in fetal LC and decreases ITT, as in rats. These findings suggest that lifting of repression by COUP-TFII may be an important mechanism that promotes increased testosterone production by fetal LC to drive masculinization. As we also show an age-related decline in expression of COUP-TFII in human fetal LC, this mechanism may also be functional in humans, and its susceptibility to disruption by environmental chemicals, stress and pregnancy hormones could explain the origin of some human male reproductive disorders
How well do computer-generated faces tap face expertise?
The use of computer-generated (CG) stimuli in face processing research is proliferating due to the ease with which faces can be generated, standardised and manipulated. However there has been surprisingly little research into whether CG faces are processed in the same way as photographs of real faces. The present study assessed how well CG faces tap face identity expertise by investigating whether two indicators of face expertise are reduced for CG faces when compared to face photographs. These indicators were accuracy for identification of own-race faces and the other-race effect (ORE)-the well-established finding that own-race faces are recognised more accurately than other-race faces. In Experiment 1 Caucasian and Asian participants completed a recognition memory task for own- and other-race real and CG faces. Overall accuracy for own-race faces was dramatically reduced for CG compared to real faces and the ORE was significantly and substantially attenuated for CG faces. Experiment 2 investigated perceptual discrimination for own- and other-race real and CG faces with Caucasian and Asian participants. Here again, accuracy for own-race faces was significantly reduced for CG compared to real faces. However the ORE was not affected by format. Together these results signal that CG faces of the type tested here do not fully tap face expertise. Technological advancement may, in the future, produce CG faces that are equivalent to real photographs. Until then caution is advised when interpreting results obtained using CG faces
- …