bluuebunny/crossref_metadata_2025 huggingface dataset:
Supplementation with whole cottonseed changes milk composition and milk fatty acid profile in dairy cows
Authors: Dayani O. , Ghorbani G. R. , Esmailizadeh A. K.
Published: January 2011

Eight multiparous Holstein cows in mid lactation (average days in milking of 160 ± 40) were used in a replicated 4 by 4 Latin square design, each experimental period lasting 3 weeks, to determine the effects of whole cottonseed (WCS) treatment and dietary crude protein (CP) concentration on the profile of milk fatty acids. Each 3-week experimental period consisted of 2 weeks for ration adaptation followed by 1 week for data collection. The experimental diets consisted of: (1) Control (without WCS), 16% CP; (2) 20% WCS, 16% CP; (3) 20% WCS, 13% CP; and (4) 20% crushed WCS, 13% CP. Minerals and vitamin supplements were the same in all experimental diets. The WCS treatment led to increased DM intake, fat-corrected milk yield, fat concentration, proportion of long-chain fatty acids, unsaturated fatty acids and ratio of unsaturated to saturated fatty acids (P < 0.05). Decreased concentration of dietary CP from 16 to 13% (diet 2 compared with diet 3) led to a decrease in both milk yield and milk composition (P < 0.05). WCS crushed in diets with 13% CP (diet 4 compared with diet 3) increased (P < 0.05) the concentration of conjugated linoleic acid in milk fat. The results demonstrated that adding WCS to the diet of lactating cows improves both milk yield and milk fatty acid profile, particularly the proportion of conjugated linoleic acid.
Effect of sorghum ergot (Claviceps africana) on the performance of steers (Bos taurus) in a feedlot
Authors: Blaney Barry J. , McLennan Stuart R. , Kidd Jim F. , Connell John A. , McKenzie Ross A. , Downing Jeff A.
Published: January 2011

The effect of ergot (Claviceps africana) in naturally infected sorghum was assessed in feedlot rations. Thirty-two Hereford steers (Bos taurus) in individual pens with access to shade were adapted to feedlot conditions and then offered one of four rations containing 0, 4.4, 8.8 or 17.6 mg/kg of ergot alkaloids (84% dihydroergosine, 10% dihydroelymoclavine and 6% festuclavine), equivalent to ~0, 10, 20 or 40 g/kg ergot (sclerotia/sphacelia) in the rations. These rations were withdrawn at noon on the second day because of severe hyperthermia and almost complete feed refusal in ergot-fed steers. After recovery on ergot-free rations for 5 days, treatment groups were incrementally introduced, over a further 3–12 days, to rations containing 0, 1.1, 2.2 or 4.4 mg/kg of alkaloids (~0, 2.5, 5 or 10 g/kg ergot, respectively). Relative exposure to ergot was maintained, so that the zero- (control), low-, medium- and high-ergot groups remained so. Steers were individually fed ad libitum, and water was freely available. Steers in all ergot-fed groups had significantly elevated rectal temperatures at 0800–1000 hours, even when the temperature–humidity index was only moderate (~70), and displayed other signs of hyperthermia (increased respiration rate, mouth breathing, excessive salivation and urination), as the temperature–humidity index increased to 73–79 during the day. Plasma prolactin was significantly reduced in ergot-fed groups. Voluntary feed intakes (liveweight basis) of the ergot-fed groups were significantly reduced, averaging 94, 86 and 86%, respectively, of the feed intakes of the control group. Hair coats were rough. While the control steers grew from a mean initial liveweight of 275 kg to a suitable slaughter weight of 455 kg in 17 weeks (growth rate 1.45 kg/day), ergot-fed groups gained only 0.77–1.10 kg/day and took at least 5 weeks longer to reach the slaughter weight, despite removal of ergot at the same time as control steers were sent to slaughter. Sorghum ergot, even at low concentrations (1.1 mg alkaloids/kg feed) is severely detrimental to the performance of steers in the feedlot.
Nutritional value of peas (Pisum sativum L.) for broilers: apparent metabolisable energy, apparent ileal amino acid digestibility and production performance
Authors: Nalle C. L. , Ravindran V. , Ravindran G.
Published: January 2011

Two experiments were conducted to evaluate the nutritional value of four cultivars (Santana, Miami, Courier and Rex) of peas (Pisum sativum L.) for broilers. In Experiment 1, the apparent metabolisable energy (AME) and the apparent ileal amino acid digestibility of these four cultivars were determined. The cultivar effects were found to be not significant (P > 0.05) for the AME and apparent ileal digestibility of amino acids, with the exception of arginine, which was lower (P < 0.05) in Courier than other cultivars. In Experiment 2, using the energy and digestible amino acid values determined in Experiment 1, diets containing 200 g/kg of the four cultivars of peas were formulated and the effects of feeding these diets on the performance and digestive tract development of broiler starters was investigated. Weight gain, feed intake and feed per gain of broiler starters fed diets containing peas were similar (P > 0.05) to those fed the maize-soybean meal diet. In general, the digestive tract development was unaffected (P > 0.05) by the inclusion of peas. The excreta scores of birds fed diets based on Santana, Miami and Rex were similar (P > 0.05) and that of the Courier-based diet was lower (P < 0.05) than those fed the maize-soy control diet. These results suggest that peas are good sources of metabolisable energy and digestible amino acids, and that they can be included at 200 g/kg level as a partial replacement for soybean meal in broiler starter diets without adverse effects on performance.
Trichomonas vaginalis infection among women in a low prevalence setting
Authors: Uddin Ruby N. N. , Ryder Nathan , McNulty Anna M. , Wray Lynne , Donovan Basil
Published: January 2011

Objectives: Trichomonas vaginalis has become rare in Australian cities but remains endemic in some remote regions. We describe the prevalence and associations of infection among women attending an urban Australian sexual health clinic. Methods: A retrospective case control study was conducted with women diagnosed with T. vaginalis at Sydney Sexual Health Centre between January 1992 and December 2006. Proforma medical records for all women were reviewed to extract demographic, behavioural and diagnostic variables using a predefined data collection instrument. Results: Over the 15-year period, 123 cases of T. vaginalis were diagnosed, with a prevalence of 0.40%. Factors independently associated with infection were older age, vaginitis symptoms (adjusted odds ratio (AOR) 6.47; 95% confidence interval (CI), 3.29–12.7), sex with a partner from outside Australia (AOR 2.33; 95% CI, 1.18–4.62), a concurrent (AOR 3.65; 95% CI, 1.23–10.8) or past (AOR 2.67; 95% CI, 1.28–5.57) sexually transmissible infection, injecting drugs (AOR 7.27; 95% CI, 1.43–36.8), and never having had a Papanicolaou smear (AOR 7.22; 95% CI, 2.81–18.9). Conclusions: T. vaginalis infection was rare in women attending our urban clinic. Rarity, combined with an association with sex outside Australia, points to imported infections accounting for a large proportion of T. vaginalis infections in an urban population. The association with never having had cervical cancer screening, along with injecting drug use, likely reflects an increased prevalence in those with reduced access to health services or poor health seeking behaviours.
Adolescent and sexual history factors influencing reproductive control among women aged 18 - 44
Authors: Magnusson Brianna M. , Masho Saba W. , Lapane Kate L.
Published: January 2011

Background: Reproductive control refers to the ability of a man or woman to control his or her own reproduction. Unintended pregnancy is a commonly used proxy measure for reproductive control. Methods: Using heterosexually active women participating in the National Survey of Family Growth Cycle 6 (n = 4521), we evaluated unintended pregnancy as a proxy measure for reproductive control. We identified four categories of women by self-reported pregnancy intention: (1) women reporting one unintended pregnancy, (2) women reporting two or more unintended pregnancies, (3) women reporting intentionally having no pregnancies and (4) women who reported that all pregnancies were intended (reference category). Polytomous logistic regression, weighted for the complex sampling design, provided estimates of odds ratios (OR) and 95% confidence intervals (CI). Results: Fifty-one percent of women who reported having one unintended pregnancy went on to experience at least one additional unintended pregnancy. Being black, Hispanic, born to a mother who was <18 years at first birth, having multiple partners and age of first sexual debut (consensual or non-consensual) were significant predictors of multiple unintended pregnancies. Relative to sexual debut after 18 years of age, women reporting a sexual debut at less than 15 years were at increased risk of multiple unintended pregnancies (adjusted OR (reported as consensual): 6.96; 95% CI: 4.26 to 11.39; adjusted OR (reported as non-consensual: 27.10; 95% CI: 11.03–66.57)). Conclusions: Efforts to delay sexual debut and to protect girls from non-consensual sex are sorely needed to prevent a lifelong trajectory of lack of reproductive control.
Sexually transmissible infections among female sex workers in Manado, Indonesia, using a multiplex polymerase chain reaction-based reverse line blot assay
Authors: Mawu Ferra O. , Davies Stephen C. , McKechnie Michelle , Sedyaningsih Endang R. , Widihastuti Asti , Hillman Richard J.
Published: January 2011

Background: Sexually transmissible infections (STIs) remain highly prevalent, and HIV is increasing, among female sex workers (FSWs) in Indonesia. Our aim was to determine the prevalence of, and risk factors for, STIs among FSWs in Manado, Indonesia. Methods: We recruited FSWs mainly at their workplace: they completed a questionnaire and provided a urine sample and self-collected vaginal swab. Samples were tested using multiplex polymerase chain reaction, followed by reverse line blot hybridisation. Results: We recruited 221 FSWs, (median age: 25 years). During the previous 3 months, 30% reported never using condoms; only 2.7% always used condoms. Of 217 women with urine samples, 49% had a ‘curable STI’: 10.6% with gonorrhoea, 26.7% with chlamydia, 12.4% with Mycoplasma genitalium and 22.6% with trichomoniasis. Independent risk factors for gonorrhoea were: domiciled outside North Sulawesi (P = 0.001) and age 16–25 years (P = 0.02); for chlamydia: no prior history of STI symptoms (P = 0.003) and age 16–25 years (P = 0.02); for Mycoplasma genitalium: number of clients on last day of sex work (P = 0.004); for trichomoniasis: number of clients per week (P = 0.04). When these four infections were grouped as any ‘curable STI’, independent associations were: number of clients on the last day of sex work (P = 0.001), age 16–25 years (P = 0.02) and sex working for fewer than 2 years (P = 0.03). Conclusions: This is the first report of M. genitalium infection in Indonesia. The high prevalence of STIs and low condom use among these FSWs suggest their vulnerability to the HIV epidemic in Indonesia. They need enhanced interventions, including outreach screening, and periodic presumptive treatment.
‘Do it yourself’ sexual health care: the user experience
Authors: Baraitser Paula , Brown Kirsty Collander , Gleisner Zachary , Pearce Vikki , Kumar Usha , Brady Michael
Published: January 2011

Objectives: To describe client experience of self-management within a busy walk-in, sexual health service. Self-management in this context is self-registration and take-home pregnancy tests, chlamydia (Chlamydia trachomatis) and gonorrhoea (Neisseria gonorrhoeae) tests, or condoms dispensed from a free vending machine. Methods: Twenty-four in-depth, semi-structured interviews with users; 19 structured written reports from mystery shoppers paid to visit the service and report their experience; demographic details of those using the self-management option from the clinic database and 40 h of recorded observation in the clinic waiting room. Results: Between 2 September 2008 and 1 September 2009, 18 657 people had 28 545 attendances at the service. Of these, 1845 (6.5%) attendances were self-managed by 1555 individuals (8.3% of all clients). Of those who self-managed, 646 (35%) obtained a chlamydia and gonorrhoea test only, 597 (32%) obtained condoms only and 488 (27%) obtained a pregnancy test only. Users valued the opportunity to self-manage because of the reduced waiting times, autonomy and privacy that such a service offers. Some prefer the additional support offered within a clinical consultation. Users made personalised decisions about self-management based on time pressure, need for additional services and preferred source of support. Users often required help and advice from client support workers to complete the self-management process. This created problems with confidentiality. Conclusions: Self-management is an acceptable option within sexual health services if informal support is available. Self-management options in clinical services could mean that 8% of clients at 6% of visits do not need to see a clinician, thus freeing up clinical capacity.
A monodactyl nonavian dinosaur and the complex evolution of the alvarezsauroid hand
Authors: Xu Xing , Sullivan Corwin , Pittman Michael , Choiniere Jonah N. , Hone David , Upchurch Paul , Tan Qingwei , Xiao Dong , Tan Lin , Han Fenglu
Published: January 2011

Digital reduction is a striking evolutionary phenomenon that is clearly exemplified in theropod dinosaurs by the functionally didactyl manus of tyrannosaurids, the flight-adapted manus of birds (Aves), and the tridactyl but digit II-dominated manus of alvarezsauroids. The enlargement of manual digit II in alvarezsauroids and the concurrent reduction of the lateral digits have been interpreted as adaptations for digging, although no detailed biomechanical analysis of hand function has so far been carried out for this group. In the derived alvarezsauroid clade Parvicursorinae, the lateral digits are so small as to be presumably vestigial. Here we report a new alvarezsauroid,
Linhenykus monodactylus
gen. et sp. nov., based on a specimen from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China. Cladistic analysis identifies
Linhenykus
as the most basal parvicursorine, and digit II of the manus retains a slender morphology and other primitive features. However,
Linhenykus
is also highly apomorphic in exhibiting the most extreme reduction of the lateral manual digits seen in any alvarezsauroid. Phalanges are retained only on the most medial digit (digit II), making
Linhenykus
the only known functionally monodactyl nonavian dinosaur. Other parvicursorines are more primitive in retaining a tridactyl manus but more derived in that digit II is highly robust and shows other apomorphic features in both of its phalanges. The unexpected combination of features seen in the hand of
Linhenykus
points to a complex mosaic pattern of manual evolution in alvarezsauroids, with loss of the presumably vestigial outer digits being decoupled from change in the form of digit II.
Neutral theory as a predictor of avifaunal extinctions after habitat loss
Authors: Halley John M. , Iwasa Yoh
Published: January 2011

The worldwide loss of natural habitats leads not only to the loss of habitat-endemic species but also to further and protracted extinctions in the reduced areas that remain. How rapid is this process? We use the neutral theory of biodiversity to answer this question, and we compare the results taken with observed rates of avifaunal extinctions. In the neutral model, we derive an exact solution for the rate of species loss in a closed community. The simple, closed-form solution exhibits hyperbolic decay of species richness with time, which implies a potentially rapid initial decline followed by much slower rates long term. Our empirical estimates of extinction times are based on published studies for avifaunal extinctions either on oceanic islands or in forest fragments, which span a total of six orders of magnitude in area. These estimates show that the time to extinction strongly depends on the area. The neutral-theory predictions agree well with observed rates over three orders of magnitude of area (between 100 and 100,000 ha) both for islands and forest fragments. Regarding the species abundance distribution, extinction times based on a broken-stick model led to better agreement with observation than if a log-series model was used. The predictions break down for very small or very large areas. Thus, neutrality may be an affordable assumption for some applications in ecology and conservation, particularly for areas of intermediate size.
Activating AMP-activated protein kinase (AMPK) slows renal cystogenesis
Authors: Takiar Vinita , Nishio Saori , Seo-Mayer Patricia , King J. Darwin , Li Hui , Zhang Li , Karihaloo Anil , Hallows Kenneth R. , Somlo Stefan , Caplan Michael J.
Published: January 2011

Renal cyst development and expansion in autosomal dominant polycystic kidney disease (ADPKD) involves both fluid secretion and abnormal proliferation of cyst-lining epithelial cells. The chloride channel of the cystic fibrosis transmembrane conductance regulator (CFTR) participates in secretion of cyst fluid, and the mammalian target of rapamycin (mTOR) pathway may drive proliferation of cyst epithelial cells. CFTR and mTOR are both negatively regulated by AMP-activated protein kinase (AMPK). Metformin, a drug in wide clinical use, is a pharmacological activator of AMPK. We find that metformin stimulates AMPK, resulting in inhibition of both CFTR and the mTOR pathways. Metformin induces significant arrest of cystic growth in both in vitro and ex vivo models of renal cystogenesis. In addition, metformin administration produces a significant decrease in the cystic index in two mouse models of ADPKD. Our results suggest a possible role for AMPK activation in slowing renal cystogenesis as well as the potential for therapeutic application of metformin in the context of ADPKD.
An aquaporin-4/transient receptor potential vanilloid 4 (AQP4/TRPV4) complex is essential for cell-volume control in astrocytes
Authors: Benfenati Valentina , Caprini Marco , Dovizio Melania , Mylonakou Maria N. , Ferroni Stefano , Ottersen Ole P. , Amiry-Moghaddam Mahmood
Published: January 2011

Regulatory volume decrease (RVD) is a key mechanism for volume control that serves to prevent detrimental swelling in response to hypo-osmotic stress. The molecular basis of RVD is not understood. Here we show that a complex containing aquaporin-4 (AQP4) and transient receptor potential vanilloid 4 (TRPV4) is essential for RVD in astrocytes. Astrocytes from AQP4-KO mice and astrocytes treated with TRPV4 siRNA fail to respond to hypotonic stress by increased intracellular Ca
2+
and RVD. Coimmunoprecipitation and immunohistochemistry analyses show that AQP4 and TRPV4 interact and colocalize. Functional analysis of an astrocyte-derived cell line expressing TRPV4 but not AQP4 shows that RVD and intracellular Ca
2+
response can be reconstituted by transfection with AQP4 but not with aquaporin-1. Our data indicate that astrocytes contain a TRPV4/AQP4 complex that constitutes a key element in the brain's volume homeostasis by acting as an osmosensor that couples osmotic stress to downstream signaling cascades.
A mechanism for graded motor control encoded in the channel properties of the muscle ACh receptor
Authors: Nishino Atsuo , Baba Shoji A. , Okamura Yasushi
Published: January 2011

The larva of the invertebrate chordate
Ciona intestinalis
possesses only 36 striated muscle cells and lacks body segmentation. It can swim, however, like a vertebrate tadpole, and how its simple body achieves such sophisticated motor control remains puzzling. We found that muscle contractions in
Ciona
larvae are variable and can be changed by sensory stimuli, so that neuromuscular transmission can convert the variable neural inputs into graded muscle activity. We characterized the molecular nature of the nicotinic acetylcholine receptor (nAChR) at neuromuscular synapses. When heterologously expressed in
Xenopus
oocytes, this nAChR channel exhibited two biophysical features resembling vertebrate neuronal nAChRs rather than the muscle type: inward rectification and high Ca
2+
permeability. Both of these properties were abolished by a simple mutation at the channel pore in one of the non-α subunits, called BGDE3, so as to adopt the sequence of related subunits in vertebrates, γ and ε. In vivo exchange of native BGDE3 with this mutant severely disrupted graded motor control, producing instead sporadic all-or-none–like flexions. The graded nature of excitation–contraction (E-C) coupling in this organism is based on the traits of the nAChR channel pore, which confer fine controllability on such a coarse motor architecture.
Lysosomal trapping of a radiolabeled substrate of P-glycoprotein as a mechanism for signal amplification in PET
Authors: Kannan Pavitra , Brimacombe Kyle R. , Kreisl William C. , Liow Jeih-San , Zoghbi Sami S. , Telu Sanjay , Zhang Yi , Pike Victor W. , Halldin Christer , Gottesman Michael M. , Innis Robert B. , Hall Matthew D.
Published: January 2011

The radiotracer [
11
C]
N-desmethyl
-loperamide (dLop) images the in vivo function of P-glycoprotein (P-gp), a transporter that blocks the entry of drugs that are substrates into brain. When P-gp is inhibited, [
11
C]dLop, a potent opiate agonist, enters and becomes trapped in the brain. This trapping is beneficial from an imaging perspective, because it amplifies the PET signal, essentially by accumulating radioactivity over time. As we previously demonstrated that this trapping was not caused by binding to opiate receptors, we examined whether [
11
C]dLop, a weak base, is ionically trapped in acidic lysosomes. To test this hypothesis, we measured [
3
H]dLop accumulation in human cells by using lysosomotropics. Because the in vivo trapping of dLop was seen after P-gp inhibition, we also measured [
3
H]dLop uptake in P-gp–expressing cells treated with the P-gp inhibitor tariquidar. All lysosomotropics decreased [
3
H]dLop accumulation by at least 50%. In P-gp–expressing cells, tariquidar (and another P-gp inhibitor) surprisingly decreased [
3
H]dLop uptake. Consequently, we measured [
11
C]dLop uptake before and after tariquidar preadministration in lysosome-rich organs of P-gp KO mice and humans. After tariquidar pretreatment in both species, radioactivity uptake in these organs decreased by 35% to 40%. Our results indicate that dLop is trapped in lysosomes and that tariquidar competes with dLop for lysosomal accumulation in vitro and in vivo. Although tariquidar and dLop compete for lysosomal trapping in the periphery, such competition does not occur in brain because tariquidar has negligible entry into brain. In summary, tariquidar and [
11
C]dLop can be used in combination to selectively measure the function of P-gp at the blood–brain barrier.
Coupling of ferredoxin and heterodisulfide reduction via electron bifurcation in hydrogenotrophic methanogenic archaea
Authors: Kaster Anne-Kristin , Moll Johanna , Parey Kristian , Thauer Rudolf K.
Published: January 2011

In methanogenic archaea growing on H
2
and CO
2
the first step in methanogenesis is the ferredoxin-dependent endergonic reduction of CO
2
with H
2
to formylmethanofuran and the last step is the exergonic reduction of the heterodisulfide CoM-S-S-CoB with H
2
to coenzyme M (CoM-SH) and coenzyme B (CoB-SH). We recently proposed that in hydrogenotrophic methanogens the two reactions are energetically coupled via the cytoplasmic MvhADG/HdrABC complex. It is reported here that the purified complex from
Methanothermobacter marburgensis
catalyzes the CoM-S-S-CoB-dependent reduction of ferredoxin with H
2
. Per mole CoM-S-S-CoB added, 1 mol of ferredoxin (Fd) was reduced, indicating an electron bifurcation coupling mechanism:

This stoichiometry of coupling is consistent with an ATP gain per mole methane from 4 H
2
and CO
2
of near 0.5 deduced from an H
2
-threshold concentration of 8 Pa and a growth yield of up to 3 g/mol methane.
VGJɸ integration and excision mechanisms contribute to the genetic diversity of
Vibrio cholerae
epidemic strains
Authors: Das Bhabatosh , Bischerour Julien , Barre François-Xavier
Published: January 2011

Most strains of
Vibrio cholerae
are not pathogenic or cause only local outbreaks of gastroenteritis. Acquisition of the capacity to produce the cholera toxin results from a lysogenic conversion event due to a filamentous bacteriophage, CTXɸ. Two
V. cholerae
tyrosine recombinases that normally serve to resolve chromosome dimers, XerC and XerD, promote CTXɸ integration by directly recombining the ssDNA genome of the phage with the dimer resolution site of either or both
V. cholerae
chromosomes. This smart mechanism renders the process irreversible. Many other filamentous vibriophages seem to attach to chromosome dimer resolution sites and participate in the rapid and continuous evolution of toxigenic
V. cholerae
strains. We analyzed the molecular mechanism of integration of VGJɸ, a representative of the largest family of these phages. We found that XerC and XerD promote the integration of VGJɸ into a specific chromosome dimer resolution site, and that the dsDNA replicative form of the phage is recombined. We show that XerC and XerD can promote excision of the integrated prophage, and that this participates in the production of new extrachromosomal copies of the phage genome. We further show how hybrid molecules harboring the concatenated genomes of CTXɸ and VGJɸ can be produced efficiently. Finally, we discuss how the integration and excision mechanisms of VGJɸ can explain the origin of recent epidemic
V. cholerae
strains.
Interspecies pheromone signaling promotes biofilm formation and same-sex mating in
Candida albicans
Authors: Alby Kevin , Bennett Richard J.
Published: January 2011

The opportunistic pathogen
Candida albicans
undergoes a parasexual mating cycle in which cells must switch from the conventional “white” form to the alternative “opaque” form to become mating competent. Pheromones secreted by opaque cells induce the formation of polarized mating projections and result in cell–cell conjugation. In contrast, white cells are unable to undergo mating, but can still respond to pheromone by expression of adhesion genes that promote biofilm formation. In this study, we have analyzed the dual ability of pheromones to activate mating by opaque cells and biofilm formation by white cells. We first show that there is considerable plasticity in interactions between the α pheromone and its receptor, Ste2, by analysis of analogs of the α pheromone. Significantly, substituted forms of α pheromone can induce a response in opaque cells and this is sufficient to drive same-sex a-a cell fusion and homothallic mating. In addition, pheromone analogs were able to induce adhesion and biofilm formation in white cells of
C. albicans
. Because of the observed plasticity in pheromone signaling, we subsequently tested putative pheromones from multiple
Candida
species and identified nonnative ligands that can induce self-mating and biofilm responses in
C. albicans
. Our findings demonstrate that environmental signals can initiate
C. albicans
parasexual reproduction and biofilm formation, and highlight the role of the pheromone-signaling apparatus in mediating these functions.
Applying a regional community concept to forest birds of eastern North America
Authors: Ricklefs Robert E.
Published: January 2011

The regional community concept embraces the idea that species interactions across large areas shape both the geographic/ecological distributions and the local abundances of populations. Within this framework, I analyzed the distribution and abundance of 79 species of land birds across 142ca. 10-ha census plots from standardized breeding bird censuses in deciduous and mixed forests of eastern North America. To characterize the regional ecological space, plots were ordinated on the basis of species abundances. Within the regional community defined by these synthetic axes, the distribution and abundance of individual species did not appear to be shaped by competition or to reflect the adaptations of individuals: (i) local abundance and population extent across the ordination axes were unrelated, (ii) pairwise correlation coefficients of species abundances were centered on 0, (iii) average species distribution and abundance were independent of the number of close relatives, and (iv) distribution and abundance exhibited no evolutionary (phylogenetic) conservatism. To explain these seemingly random patterns, I speculate that species are approximately evenly matched competitors over much of the region and that their distributions and relative abundances are determined by the labile coevolutionary outcomes of interactions with specialized pathogens. Thus, despite the appearance that random processes determine patterns in the distribution and abundance of populations in the regional community, it is plausible that species-specific deterministic interactions are responsible. Although competition is a dominant force in ecological communities, variation in the distribution and abundance of individual species might instead reflect the outcome of interactions with specialized antagonists, including pathogens.
Symmetry, asymmetry, and kinetics of silencing establishment in
Saccharomyces cerevisiae
revealed by single-cell optical assays
Authors: Osborne Erin A. , Hiraoka Yasushi , Rine Jasper
Published: January 2011

In
Saccharomyces cerevisiae
, silent chromatin inhibits the expression of genes at the
HML
,
HMR
, and telomeric loci. When silent chromatin forms de novo, the rate of its establishment is influenced by different chromatin states. In particular, loss of the enzyme Dot1, an H3 K79 methyltransferase, leads to rapid silencing establishment. We tested whether silencing establishment was antagonized by H3 K79 methylation or by the Dot1 protein itself competing with Sir3 for binding sites on nucleosomes. To do so, we monitored fluorescence activity in cells containing a
GFP
gene within the
HML
locus during silencing establishment in a series of
dot1
and histone mutant backgrounds. Silencing establishment rate was correlated with Dot1’s enzymatic function rather than with the Dot1 protein itself. In addition, histone mutants that mimicked the conformation of unmethylated H3 K79 increased the rate of silencing establishment, indicating that the H3 K79 residue affected silencing independently of Dot1 abundance. Using fluorophore-based reporters, we confirmed that mother and daughter cells often silence in concert, but in instances where asymmetric silencing occurs, daughter cells established silencing earlier than their mothers. This noninvasive technique enabled us to demonstrate an asymmetry in silencing establishment of a key regulatory locus controlling cell fate.
Proof of George Andrews’s and David Robbins’s
q
-TSPP conjecture
Authors: Koutschan Christoph , Kauers Manuel , Zeilberger Doron
Published: January 2011

The conjecture that the orbit-counting generating function for totally symmetric plane partitions can be written as an explicit product formula has been stated independently by George Andrews and David Robbins around 1983. We present a proof of this long-standing conjecture.
Casein kinase-2 mediates cell survival through phosphorylation and degradation of inositol hexakisphosphate kinase-2
Authors: Chakraborty Anutosh , Werner J. Kent , Koldobskiy Michael A. , Mustafa Asif K. , Juluri Krishna R. , Pietropaoli Joseph , Snowman Adele M. , Snyder Solomon H.
Published: January 2011

The inositol pyrophosphate, diphosphoinositol pentakisphosphate, regulates p53 and protein kinase Akt signaling, and its aberrant increase in cells has been implicated in apoptosis and insulin resistance. Inositol hexakisphosphate kinase-2 (IP6K2), one of the major inositol pyrophosphate synthesizing enzymes, mediates p53-linked apoptotic cell death. Casein kinase-2 (CK2) promotes cell survival and is upregulated in tumors. We show that CK2 mediated cell survival involves IP6K2 destabilization. CK2 physiologically phosphorylates IP6K2 at amino acid residues S347 and S356 contained within a PEST sequence, a consensus site for ubiquitination. HCT116 cells depleted of IP6K2 are resistant to cell death elicited by CK2 inhibitors. CK2 phosphorylation at the degradation motif of IP6K2 enhances its ubiquitination and subsequent degradation. IP6K2 mutants at the CK2 sites that are resistant to CK2 phosphorylation are metabolically stable.
Yes-associated protein (YAP) transcriptional coactivator functions in balancing growth and differentiation in skin
Authors: Zhang Haiying , Pasolli H. Amalia , Fuchs Elaine
Published: January 2011

In mammals, skin begins as a single-layered epithelium, which, through a series of signals, either stratifies and differentiates to become epidermis or invaginates downward to make hair follicles (HFs). To achieve and maintain proper tissue architecture, keratinocytes must intricately balance growth and differentiation. Here, we uncover a critical and hitherto unappreciated role for Yes-associated protein (YAP), an evolutionarily conserved transcriptional coactivator with potent oncogenic potential. We show that YAP is highly expressed and nuclear in single-layered basal epidermal progenitors. Notably, nuclear YAP progressively declines with age and correlates with proliferative potential of epidermal progenitors. Shortly after initiation of HF morphogenesis, YAP translocates to the cytoplasm of differentiating cells. Through genetic analysis, we demonstrate a role for YAP in maintaining basal epidermal progenitors and regulating HF morphogenesis. YAP overexpression causes hair placodes to evaginate into epidermis rather than invaginate into dermis. YAP also expands basal epidermal progenitors, promotes proliferation, and inhibits terminal differentiation. In vitro gain-and-loss of function studies show that primary mouse keratinocytes (MKs) accelerate proliferation, suppress differentiation, and inhibit apoptosis when YAP is activated and reverse these features when YAP is inhibited. Finally, we identify
Cyr61
as a target of YAP in MKs and demonstrate a requirement for TEA domain (TEAD) transcriptional factors to comediate YAP functions in MKs.
C-KIT mutation cooperates with full-length AML1-ETO to induce acute myeloid leukemia in mice
Authors: Wang Yue-Ying , Zhao Li-Juan , Wu Chuan-Feng , Liu Ping , Shi Lin , Liang Yang , Xiong Shu-Min , Mi Jian-Qing , Chen Zhu , Ren Ruibao , Chen Sai-Juan
Published: January 2011

The full-length
AML1-ETO
(
AE
) fusion gene resulting from t(8;21)(q22;q22) in human acute myeloid leukemia (AML) is not sufficient to induce leukemia in animals, suggesting that additional mutations are required for leukemogenesis. We and others have identified activating mutations of
C-KIT
in nearly half of patients with t(8;21) AML. To test the hypothesis that activating
C-KIT
mutations cooperate with
AE
to cause overt AML, we generated a murine transduction and transplantation model with both mutated
C-KIT
and
AE
. To overcome the intracellular transport block of human C-KIT in murine cells, we engineered hybrid C-KIT (HyC-KIT) by fusing the extracellular and transmembrane domains of the murine c-Kit in-frame to the intracellular signaling domain of human C-KIT. We showed that tyrosine kinase domain mutants HyC-KIT N822K and D816V, as well as juxtamembrane mutants HyC-KIT 571+14 and 557-558Del, could transform murine 32D cells to cytokine-independent growth. The protein tyrosine kinase inhibitor dasatinib inhibited the proliferation of 32D cells expressing these C-KIT mutants, with potency in the low nanomolar range. In mice, HyC-KIT N822K induced a myeloproliferative disease, whereas HyC-KIT 571+14 induces both myeloproliferative disease and lymphocytic leukemia. Interestingly, coexpression of AE and HyC-KIT N822K led to fatal AML. Our data have further enriched the two-hit model that abnormalities of both transcription factor and membrane/cytosolic signaling molecule are required in AML pathogenesis. Furthermore, dasatinib prolonged lifespan of mice bearing AE and HyC-KIT N822K-coexpressing leukemic cells and exerted synergic effects while combined with cytarabine, thus providing a potential therapeutic for t(8;21) leukemia.
Human IL-3/GM-CSF knock-in mice support human alveolar macrophage development and human immune responses in the lung
Authors: Willinger Tim , Rongvaux Anthony , Takizawa Hitoshi , Yancopoulos George D. , Valenzuela David M. , Murphy Andrew J. , Auerbach Wojtek , Eynon Elizabeth E. , Stevens Sean , Manz Markus G. , Flavell Richard A.
Published: January 2011

Mice with a functional human immune system have the potential to allow in vivo studies of human infectious diseases and to enable vaccine testing. To this end, mice need to fully support the development of human immune cells, allow infection with human pathogens, and be capable of mounting effective human immune responses. A major limitation of humanized mice is the poor development and function of human myeloid cells and the absence of human immune responses at mucosal surfaces, such as the lung. To overcome this, we generated human IL-3/GM-CSF knock-in (hIL-3/GM-CSF KI) mice. These mice faithfully expressed human GM-CSF and IL-3 and developed pulmonary alveolar proteinosis because of elimination of mouse GM-CSF. We demonstrate that hIL-3/GM-CSF KI mice engrafted with human CD34
+
hematopoietic cells had improved human myeloid cell reconstitution in the lung. In particular, hIL-3/GM-CSF KI mice supported the development of human alveolar macrophages that partially rescued the pulmonary alveolar proteinosis syndrome. Moreover, human alveolar macrophages mounted correlates of a human innate immune response against influenza virus. The hIL-3/GM-CSF KI mice represent a unique mouse model that permits the study of human mucosal immune responses to lung pathogens.
Homeostatic proliferation generates long-lived natural killer cells that respond against viral infection
Authors: Sun Joseph C. , Beilke Joshua N. , Bezman Natalie A. , Lanier Lewis L.
Published: January 2011

Cells of the immune system undergo homeostatic proliferation during times of lymphopenia induced by certain viral infections or caused by chemotherapy and radiation treatment. Natural killer (NK) cells are no exception and can rapidly expand in number when placed into an environment devoid of these cells. We explored the lifespan and function of mouse NK cells that have undergone homeostatic proliferation in various settings of immunodeficiency. Adoptive transfer of mature NK cells into lymphopenic mice resulted in the generation of a long-lived population of NK cells. These homeostasis-driven NK cells reside in both lymphoid and nonlymphoid organs for >6 mo and, similar to memory T cells, self-renew and slowly turn over at steady state. Furthermore, homeostatically expanded NK cells retained their functionality many months after initial transfer and responded robustly to viral infection. These findings highlight the ability of mature NK cells to self-renew and possibly persist in the host for months or years and might be of clinical importance during NK cell adoptive immunotherapy for the treatment of certain cancers.
Comparison between lasers and relativistic electron beams for controlled fusion
Authors: Bobin J.L.
Published: January 2011

When concentrated on a solid surface, relativistic electron beams, like laser beams, generate a high-temperature dense plasma. The paper discusses how these two energy sources are compatible with the break-even requirements in systems where the spherical target is compressed, the parameters of comparison being the available energy and flux and the different yields characteristic of each system and of the beam plasma coupling.
Radiation Effects and Tritium Technology for Fusion Reactors (Report on the International Conference Gatlinburg 1975
Authors: Wiffen F.W. , Watson J.S.
Published: January 2011

The high level of interest in the prediction and evaluation of radiation effects in fusion reactors was underlined by the success of the Gatlinburg Conference. Of the more than 300 total conference attendants, 150 to 200 attended the Radiation Effects sessions. There was a total of 56 papers on radiation effects, contributed from the United States of America (41), the United Kingdom (5), the Federal Republic of Germany (5), Japan (3), Canada (1) and South Africa (1). In classifying the papers by subject, the greatest emphasis was on the examination of the microstructures of irradiated samples, with 18 papers, closely followed by papers that could be grouped as theory, modelling or analytical treatments of radiation effects, with 15 papers. Experimental techniques for the evaluation of radiation effects were highlighted in 7 papers, and 7 papers dealt with radiation-produced changes in physical properties. The fraction of effort devoted to the effect of irradiation on mechanical properties was disappointingly small, with only 5 papers on this important topic. The final subject division of design analysis included 4 papers that considered the effects of different reactor design options on the radiation response of materials.
Axial potential profiles in thermal-barrier cells
Authors: Cohen R.H.
Published: January 2011

The potential profile in the vicinity of the throat of a tandem-mirror thermal-barrier cell is studied. A model ion distribution function which resembles that obtained from numerical Fokker-Planck code studies is used. For all but very small ratios of trapped- to passing-particle densities, the self-consistent potential satisfies quasi-neutrality and varies gradually between its value just beyond the throat and a depressed value in the interior of the barrier cell. As the trapped-particle density decreases, a sheath develops at a finite distance from the mirror throat. For still lower trapped-particle densities, the throat region ceases to be quasineutral; the solution to Poisson's equation is a sheath-like structure whose height depends on the net charge density at the throat, which, in turn, is determined by the requirement that the solution match smoothly to the profile in the adjacent cell.
Energy principle for stability of general force-free MHD equilibria
Authors: Chu M.S. , Jensen T.H. , Lee J.K.
Published: January 2011

An energy principle has been constructed for the determination of stability of general force-free equilibria against ideal- and dissipative-(tearing)-MHD modes. The concept of accessible neighbouring equilibria, with the inclusion of singular currents on mode rational surfaces, is used. The driving source of these instabilities may be either the parallel current density or the parallel current density gradient. This energy principle is well suited for numerical implementation. Reduction of this energy principle to some known cases is also presented
Data Compendium for Plasma-Surface Interactions
Authors: Langley R.A. , Bohdansky J. , Eckstein W. , Mioduszewski P. , Roth J. , Taglauer E. , Thomas E.W. , Verbeek H. , Wilson K.L.
Published: January 2011

A review of particle-solid processes pertinent to modelling plasma-wall interactions is presented, and sets of recommended data are given. Analytic formulas are used where possible; otherwise, data are presented in the form of tables and graphs. The incident particles considered are e−, H, D, T, He, C, O, and selfions. The materials include the metals aluminum, beryllium, copper, molybdenum, stainless steel, titanium, and tungsten and the nonmetals carbon and TiC. The processes covered are light ion reflection, hydrogen and helium trapping and detrapping, desorption, evaporation, sputtering, chemical effects in sputtering, blistering caused by implantation of helium and hydrogen, secondary electron emission by electrons and particles, and arcing.
Recent progress in production and evaluation of atomic data for fusion: Review of a Co-ordinated Research Programme of the IAEA
Authors: Janev R.K. , Katsonis K.
Published: January 2011

Work produced in the framework of the IAEA (1980-1984) Co-ordinated Research Programme (CRP) on Atomic Collision Data for Diagnostics of Magnetic Fusion Plasmas is reviewed. The conclusions of this programme and the recommended continuation of the overall work on Atomic and Molecular (A + M) data discussed during three meetings sponsored by the IAEA are presented in detail. For the purpose of completeness, the present review also provides information on data produced and/or evaluated outside this CRP, as well as data relevant to fusion plasma modelling. The highlights of data production and evaluation activity after termination of the CRP are also covered.
Exact and approximate solutions to the finite temperature wave equation in a one-dimensional perpendicularly stratified plasma
Authors: Jaeger E.F. , Batchelor D.B. , Weitzner H.
Published: January 2011

The sixth order wave equation which results from a finite temperature expansion of the Vlasov equation is solved globally in the ion cyclotron range of frequencies. A perpendicularly stratified, onedimensional slab plasma is assumed. The diamagnetic drift and the associated anisotropy are included in the unperturbed distribution function to ensure a self-adjoint system. All x-dependence in the plasma pressure and magnetic field is retained along with the electric field parallel to B⃗. Thus, Landau damping of the ion Bernstein wave is included self-consistently. Because of the global nature of the solution, the evanescent short wavelength Bernstein waves do not grow exponentially as in shooting methods. Strong variations occur in the absorption and in the structure of the wave fields as resonance topology is varied. Solutions to the complete sixth order differential equation are compared to those from an approximate second order equation based on local dispersion theory.
Analysis of impurity confinement experiments with co- and counter-injected neutral beams in the ISX-B and PLT tokamaks
Authors: Stacey W.M. , Malik M.A.
Published: January 2011

An extended impurity transport theory, which includes NBI momentum input and radial momentum transfer effects, inertial strong-rotation (vø∼ vth) effects and radial electric field effects, has been applied to analyse the impurity accumulation experiments in ISX-B and PLT. Theory and experiment are found to be in good agreement. Counter-injection causes a central impurity accumulation that is several times larger than for co-injection, and this difference can be understood in terms of differences in transport properties between co-injection and counter-injection.
Spectroscopic determination of hydrogen and electron densities in plasma in the ionizing phase: Application to WT-III
Authors: Fujimoto T. , Sawada K. , Takahata K. , Eriguchi K. , Suemitsu H. , Ishii K. , Okasaka R. , Tanaka H. , Maekawa T. , Terumichi Y. , Tanaka S.
Published: January 2011

The Balmer line intensities of atomic hydrogen from the WT-III tokamak plasma have been observed and interpreted in terms of the collisional-radiative model. The atomic and molecular hydrogen densities are deduced together with the electron density. Going from the plasma centre to the edge region along the minor radius, the atomic hydrogen density increases slightly and molecular hydrogen is found only in the periphery. In the edge region, the atomic hydrogen density reaches 1 × 1016 m−3 and the molecular hydrogen density 4 × 10l7 m−3. The electron density distribution is consistent with that determined by infrared laser interferometry.