bluuebunny/crossref_metadata_2025 huggingface dataset:
A LYST/beige homolog is involved in biogenesis ofDictyosteliumsecretory lysosomes
Authors: Charette Steve J. , Cosson Pierre
Published: July 2007

Chediak-Higashi syndrome (CHS) is characterized at the cellular level by a defect in the ability of cells to secrete lysosomes. However, the precise step affected in the secretion process is unclear. We characterized Dictyostelium discoideum cells containing a mutation in lvsB, the homolog of the human gene (LYST) involved in CHS. As observed in mammalian cells, secretion of lysosome-derived compartments was affected in lvsB mutant cells. This defect was mirrored by a decrease in the number of fusion-competent post-lysosomal compartments, which in Dictyostelium can be clearly distinguished from lysosomes. In addition, the transfer of endocytosed particles from lysosomes to post lysosomes was strongly diminished in lvsB mutant cells compared with the wild type. These results suggest that LvsB is primarily involved in transport from lysosomes to post lysosomes, and thus plays a critical role in the maturation of lysosomes into fusion-competent post-lysosomal compartments.
Unconventional secretion: an extracellular trap for export of fibroblast growth factor 2
Authors: Nickel Walter
Published: July 2007

Several secretory proteins are released from cells by mechanisms that are distinct from the classical endoplasmic reticulum (ER)/Golgi-mediated secretory pathway. Recent studies unexpectedly revealed that the interaction between one such protein, fibroblast growth factor 2 (FGF-2), and cell surface heparan sulfate proteoglycans (HSPGs) is essential for secretion. FGF-2 mutants that cannot bind to heparan sulfates are not secreted, and cells that do not express functional HSPGs cannot secrete wild-type FGF-2. FGF-2 appears to be secreted by direct translocation across the plasma membrane in an ATP- and membrane-potential-independent manner. I propose that its translocation across the membrane is a diffusion-controlled process in which cell surface HSPGs function as an extracellular molecular trap that drives directional transport of FGF-2.
Cooperative roles of Par-3 and afadin in the formation of adherens and tight junctions
Authors: Ooshio Takako , Fujita Naoyuki , Yamada Akio , Sato Tatsuhiro , Kitagawa Yuichi , Okamoto Ryoko , Nakata Shinsuke , Miki Ayaka , Irie Kenji , Takai Yoshimi
Published: July 2007

Par-3 is a cell-polarity protein that regulates the formation of tight junctions (TJs) in epithelial cells, where claudin is a major cell-cell adhesion molecule (CAM). TJs are formed at the apical side of adherens junctions (AJs), where E-cadherin and nectin are major CAMs. We have revealed that nectin first forms cell-cell adhesions, and then recruits cadherin to nectin-based cell-cell adhesion sites to form AJs and subsequently recruits claudin to the apical side of AJs to form TJs. The cytoplasmic tail of nectin binds afadin and Par-3. Afadin regulates the formation of AJs and TJs cooperatively with nectin. Here, we studied the role of Par-3 in the formation of these junctions by using Par-3-knockdown MDCK cells. Par-3 was necessary for the formation of AJs and TJs but was not necessary for nectin-based cell-cell adhesion. Par-3 promoted the association of afadin with nectin, whereas afadin was not necessary for the association of Par-3 with nectin. However, the association of afadin with nectin alone was not sufficient for the formation of AJs or TJs, and Par-3 and afadin cooperatively regulated it. We describe here these novel roles of Par-3 in the formation of junctional complexes.
Cellulose-binding Heptapeptides Identified by Phage Display Methods
Authors: Serizawa Takeshi , Iida Kyoko , Matsuno Hisao , Kurita Kimio
Published: July 2007

Phage libraries displaying random and linear heptapeptides were applied to crystalline cellulose. Binding affinities of obtained phage clones were quantitatively analyzed by enzyme-linked immunosorbent assays (ELISAs). Clones were obtained with greater apparent affinity constants (Kapps) than those of the library, suggesting the isolation of cellulose-binding peptides with characteristic sequences.
Palladium–Copper/Hydrophobic Active Carbon as a Highly Active and Selective Catalyst for Hydrogenation of Nitrate in Water
Authors: Wang Yi , Kasuga Tomohiro , Mikami Ikkou , Kamiya Yuichi , Okuhara Toshio
Published: July 2007

Cu–Pd supported on active carbon (AC), in which Cu/Pd ratio is strictly controlled, is an excellent catalyst for selective hydrogenation of NO3− to harmless products in the presence of H2 at low partial pressure. 3.6 wt % Cu; 2.0 wt % Pd/AC, coupled with another Pd/AC catalyst, showed high selectivity to N2 (98% at 298 K), while suppressing NH3 production (2% selectivity, 0.5 from 100 ppm of NO3−). Modification of the Cu–Pd/AC catalyst with PTFE results in further enhancement; the activity more than tripled, while suppression of NH3 production was retained.
Oxygen consumption, activity and body fat in normal and hairless mice
Authors: Donnelly H. T.
Published: July 2007

The oxygen consumption and spontaneous activity of A2G ( hr/+), A2G ( hr/hr) and NMRI mice in groups of 2, 3, or 5 were measured, and body fat content was also determined. Average rates of oxygen consumption were found to be lowest in the A2G ( hr/+) and highest in the A2G ( hr/hr) mice, and conversely for the proportion of total body fat. There was no difference in activity of A2G ( hr/+) and A2G ( hr/hr), but the NMRI mice were more active.
Laboratory rearing of woodpigeons (Columba palumbus)
Authors: Haque A. K. M. Fazlul , Broom D. M. , Gaitens J. F.
Published: July 2007

18 woodpigeons were reared. Weight gain was similar to that of wild-reared birds if they were collected from the nest at 5-11 days of age, but slower if they were collected later.

The woodpigeon ( Columba palumbus) is an agricultural pest in Britain. As part of a field and laboratory study of pigeon-scaring methods, we have reared woodpigeons in captivity. There are very few reports on hand-rearing of woodpigeons in laboratory conditions. Colquhoun (1951) recorded the bodyweight of squabs (young pigeons) during laboratory rearing. These weights were much lower than those recorded by Murton, Isaacson & Westwood (1963) for birds of comparable age in field studies. Kenward & Sibly (1978) also reported the hand-rearing of woodpigeons. The present paper deals with the methods of rearing and with weight gain in the laboratory.
Organophosphate poisoning in marmosets
Authors: Brack M. , Rothe H.
Published: July 2007

Due to faulty use of a chlorpyriphos-diazinon combination as a pesticide within a laboratory animal house, 19 marmosets of 2 species ( Saguinus fuscicollis and Callithrix jacchus) of 98 at risk died from organophosphorous poisoning (19% mortality). The clinical signs were those of cholinesterase inhibitors. The morphological lesions consisted predominantly of haemorrhages in several organs, particulary the CNS, and of bone marrow necroses.
Coprophagy in iron-deficient rats
Authors: Neale R. J.
Published: July 2007

An attempt was made to prevent coprophagy in iron-deficient rats using plastic anal cups. Considerable damage to the anal cups occurred as a result of gnawing over periods up to 4 days. Haemoglobin iron determinations in rats with and without cups suggested that the cups had been partially successful in preventing recycling of dietary iron, and that coprophagy may be a significant factor in interpretation of haemoglobin regeneration studies on rodents.
Lifetime reproductive performance of Mongolian gerbils (Meriones unguiculatus) with 1 or 2 ovaries
Authors: Norris M. L. , Adams C. E.
Published: July 2007

The lifetime reproductive performance of Mongolian gerbils from which an ovary had been removed 7 days before pairing at 100 days of age was only slightly inferior to that of normal females. A general decline in fertility was evident only in the oldest females. The mean number of litters, young born and age at last parturition were 7·6 ± 3·8, 37 ± 20 and 462 ± 196 days (2 ovaries) compared with 6·9 ± 3·5, 30 ± 16 and 417 ± 142 days (1 ovary) respectively.
Effect of inbreeding on juvenile mortality in some small mammal species
Authors: Ralls Katherine , Ballou Jonathan
Published: July 2007

In breeding records for 12 species of small mammals from 9 families in 3 orders, individuals with an inbreeding coefficient of 0 were classified as noninbred, those with inbreeding coefficients greater than 0 as inbred. Juvenile mortality was defined as all deaths prior to ½ of the age of sexual maturity for each species. It was significantly higher for inbred than for noninbred animals in 11 of the 12 species using a 1-tailed sign test, and by Fisher's exact test in 3 species, Monodelphis domestica, Wiedomys pyrrhorhinos and Dolichotis salinicola. The higher mortality of inbred young of the species with the largest sample size, Elephantulus rufescens, was irrespective of litter size and of the parity of the dam.
False negative hyperglucosuria test-strip reactions in laboratory mice
Authors: Taylor D. M. , Neal D. L.
Published: July 2007

Inhibition of a variety of commercial test strips for hyperglucosuria was experienced in laboratory mice. All mouse strains tested were found to have sufficiently high levels of ascorbic acid to cause inhibition, and male levels were higher than those of females. A regime to obtain optimum detection of positive results is discussed.
Long-term experiments with a newly-developed standardized diet for the New World primates Callithrix jacchus jacchus and Callithrix jacchus penicillata (marmosets)
Authors: Wirth H. , Buselmaier W.
Published: July 2007

A long-term feeding study lasting more than 4 years is described during which a newly-developed complete diet for marmosets was evaluated. Using this diet, it was possible to adapt the feeding habits and dietary requirements of these increasingly popular South American non-human primates to standardized laboratory conditions.
Haematology of conventionally-maintained Lac:P outbred Wistar rats during the 1st year of life
Authors: Archer R. K. , Festing M. F. W. , Riley Joan
Published: July 2007

Healthy Lac:P Wistar rats reached a plateau for red-cell parameters at about 18 weeks of age. For the next 9 months the values remained substantially constant. White-cell parameters varied in a more complex manner, and were largely unrelated to bodyweight.
Haematological and serum chemistry profiles of ferrets (Mustela putorius furo)
Authors: Lee Elsbeth J. , Moore W. E. , Fryer H. C. , Minocha H. C.
Published: July 2007

Female, male and castrated male ferrets were studied. Weight gain plateaued at 28-weeks of age with males about 500 g heavier than females. No statistically significant differences in haematology were observed with age, but alkaline phosphatase and alanine aminotransferase levels fell while glucose increased. Haemolysis led to various changes including marked increases in total protein, albumin, inorganic phosphate and sorbitol dehydrogenase.
Inactivation of the p16 Cyclin-Dependent Kinase Inhibitor in High-Grade Canine Non-Hodgkin's T-Cell Lymphoma
Authors: Fosmire S. P. , Thomas R. , Jubala C. M. , Wojcieszyn J. W. , Valli V. E. O. , Getzy D. M. , Smith T. L. , Gardner L. A. , Ritt M. G. , Bell J. S. , Freeman K. P. , Greenfield B. E. , Lana S. E. , Kisseberth W. C. , Helfand S. C. , Cutter G. R. , Breen M. , Modiano J. F.
Published: July 2007

The significance of p16/Rb tumor suppressor pathway inactivation in T-cell non-Hodgkin's lymphoma (NHL) remains incompletely understood. We used naturally occurring canine NHL to test the hypothesis that p16 inactivation has specific pathologic correlates. Forty-eight samples (22 T-cell NHL and 26 B-cell NHL) were included. As applicable, metaphase- or array-based comparative genomic hybridization, Southern blotting, promoter methylation, and Rb phosphorylation were used to determine the presence, expression, and activity of p16. Fisher's exact test was used to test for significance. Deletion of p16 (or loss of dog chromosome 11) was restricted to high-grade T-cell NHL (lymphoblastic T-cell lymphoma and peripheral T-cell lymphoma, not otherwise specified). These were characterized by a concomitant increase of tumor cells with Rb phosphorylation at canonical CDK4 sites. Rb phosphorylation also was seen in high-grade B-cell NHL (diffuse large B-cell lymphoma and Burkitt-type lymphoma), but in those cases, it appeared to be associated with c-Myc overexpression. The data show that p16 deletion or inactivation occurs almost exclusively in high-grade T-cell NHL; however, alternative pathways can generate functional phenotypes of Rb deficiency in low-grade T-cell NHL and in high-grade B-cell NHL. Both morphologic classification according to World Health Organization criteria and assessment of Rb phosphorylation are prognostically valuable parameters for canine NHL.
Simultaneous Canine Distemper Virus, Canine Adenovirus Type 2, and Mycoplasma Cynos Infection in a Dog with Pneumonia
Authors: Chvala S. , Benetka V. , Möstl K. , Zeugswetter F. , Spergser J. , Weissenböck H.
Published: July 2007

The present case is the first description of a triple infection with canine distemper virus (CDV), canine adenovirus (CAV) type 2, and Mycoplasma cynos in a dog. The 5-month-old female Miniature Pinscher was euthanized because of dyspnea, croaking lung sounds, weight loss, and lymphopenia. Pathologic examination revealed a fibrinous necrotizing pneumonia with large amphophilic intranuclear and acidophilic intracytoplasmatic inclusion bodies in different lung cells. Immunohistochemically, CDV antigen was present in lung and many other organs. In situ hybridization for detection of CAV nucleic acid showed positive signals in the lung only. Polymerase chain reaction of lung tissue and consecutive sequencing of the amplification product identified CAV type 2. Bacteriologic examination of lung tissue yielded large amounts of M cynos. This infection was confirmed by immunohistochemistry detecting abundant positive signals in the lung tissue.
Characterization of a Population of Unique Granular Lymphocytes in a Bitch Deciduoma, Using a Panel of Histo- and Immunohistochemical Markers
Authors: Arrighi S. , Cremonesi F. , Bosi G. , Groppetti D. , Pecile A.
Published: July 2007

The ovaries and uterus were collected after ovariohysterectomy from a 16-month-old Labrador bitch in diestrus that never mated. Discrete swellings were found in the uterine horns, with the macroscopic appearance of normal early pregnancy. At histologic examination, the endometrium, devoid of any conceptus and chorion, showed a marked proliferation, on the basis of which a diagnosis of deciduoma was made. A remarkable population of stromal eosinophilic granular lymphocytes was present, especially in the axis of the endometrial folds. Periodic acid-Schiff and Dolichos biflorus-lectin histochemical reaction and a panel of 10 immunohistochemical markers were used to characterize eosinophilic granular cells. Our findings allowed us to compare these granular cells with the granulated decidual cells, whose presence was until now described only in primates, rodents, or a few other epitheliochorial species. On the basis of our results, the importance of eosinophilic granular cells in a decidualization process is hypothesized to occur also in the bitch.
Mammary Carcinoma with Sebaceous Differentiation in a Dog
Authors: Chang S.-C. , Liao J.-W. , Wong M.-L. , Lai Y.-S. , Liu C.-I.
Published: July 2007

This report describes an invasive mammary carcinoma with a rare distinctive feature characterized by sebaceous differentiation of tumor cells. This tumor occurred in a 10-year-old female mixed breed dog. The patient had two masses in the left fifth mammary gland. Grossly, the masses were firm, whitish to light brown, and superficially ulcerated. On cut surface, they were multilobulated with foci of necrosis. Microscopically, the tumors were composed of two distinctive neoplastic components, intraductal papillary adenocarcinoma and sebaceous carcinoma. The regions of sebaceous tumor were clumped separately, contained well-developed sebaceous cells and keratinized epithelial cells, and were surrounded by few to several layers of basaloid cells. The cells with abundant foamy cytoplasm that resembled sebaceous cells were also found within the intraductal papillary-like nests of mammary carcinoma, providing evidence of sebaceous metaplasia. Sebaceous differentiation in a mammary gland tumor is possible, because skin appendages and ductal apparatus of the mammary gland share a common anlagen. This tumor had an aggressive behavior with lymphatic metastasis. Consequentially, the dog had a poor prognosis.
Mycobacterium fortuitum Pneumonia in a Cat and the Role of Lipid in the Pathogenesis of Atypical Mycobacterial Infections
Authors: Couto S. S. , Artacho C. A.
Published: July 2007

Mycobacterium fortuitum is a saprophytic, fast-growing, nontuberculous, and nonlepromatous mycobacterium that can cause infections in animals and humans. In dogs and cats, it is one of the most common agents of ulcerative dermatitides and panniculitides caused by atypical mycobacteria. In humans, it is frequently found in lipoid pneumonias or contaminated surgical sites. We report a cat with granulomatous pneumonia caused by M fortuitum resembling lipoid pneumonia in humans. The similarity between the histopathology of the lung and skin lesions caused by this organism in dogs and cats is emphasized. We discuss the role of lipids in the pathogenesis of mycobacterioses and suggest an association between atypical mycobacteria and lipid-rich environments. We conclude that M fortuitum should be included as a differential in cases of lipid-rich pneumonias that do not respond to common antibiotics.
Canine Hyperplastic Intraepidermal Pustular and Suprabasal Acantholytic Dermatosis with Features of Human Pemphigus Vegetans
Authors: Heimann M. , Beco L. , Petein M. , Nishifuji K. , Amagai M. , Olivry D. T.
Published: July 2007

Pemphigus vegetans is a rare autoimmune blistering acantholytic dermatosis of humans that combines unusually hyperplastic and verrucous pustular skin lesions and mucosal erosions. We report herein the clinical, histopathologic, and immunologic findings in a dog whose lesions resembled, but were not identical to, those of human pemphigus vegetans. A 4-year-old male Greater Swiss Mountain Dog presented with multifocal cutaneous verrucous and crusted papules and pustules, as well as skin and mucosal erosions and ulcers. Microscopic lesions consisted of exophytic papillated epidermal hyperplasia, superficial and deep intraepidermal acantholytic neutrophilic and eosinophilic pustules, and suprabasal epidermal clefts leaving rounded basal keratinocytes at the bottom of the vesicles. Direct and indirect immunofluorescence revealed antikeratinocyte IgG autoantibodies. Immunoprecipitation immunoblotting and immunoabsorption experiments with recombinant canine desmogleins confirmed that autoantibodies recognized desmoglein-1. In this dog, clinical and histopathologic features resembled those of human pemphigus vegetans, while circulating autoantibodies against canine desmoglein-1 were solely identified. This antigen target is different from that of the human disease in which antidesmoglein-3 autoantibodies are detected most commonly.
Alendronate Has an Anabolic Effect on Bone Through the Differentiation of Mesenchymal Stem Cells
Authors: Duque Gustavo , Rivas Daniel
Published: July 2007

We committed MSCs to differentiate into either osteoblasts or adipocytes and examined the effect of ALN on both adipogenesis and osteoblastogenesis. ALN inhibited adipogenesis while promoting osteoblast differentiation and activity. Our results reveal a new anabolic effect of ALN in differentiating bone marrow cells.

Introduction: Alendronate (ALN) prevents bone loss in postmenopausal patients through the regulation of osteoclastic activity. However, it has also proven to be effective in older adults where the pathophysiological mechanism is the predominance of adipogenesis over osteoblastogenesis. The aim of this study is to determine the in vitro effect of ALN on both osteoblastogenesis and adipogenesis.

Materials and Methods: Human mesenchymal stem cells (MSCs) were plated at a density of 5 × 105 cells/well in 100-cm 2 dishes containing MSC growth media. After confluence, cells were committed to differentiate adding either adipogenic or osteogenic media with and without 1,25(OH)2D3 (10−8 M) and supplemented with ALN at increasing concentrations (10−9 to 10−7 M). Untreated differentiating MSCs were used as control. Alkaline phosphatase (ALP), oil red O, and Alizarin red staining were performed at timed intervals (weeks 1 and 2). Additionally, levels of expression of both osteogenesis and adipogenesis transcription factors were measured in protein extracts. Finally, the effect of ALN on PPARγ2 nuclear activation complex was assessed.

Results: We found that ALN has a significant and dose-dependent effect on osteoblastogenesis. This effect was not modified by the presence of 1,25(OH)2D3 in the medium. Furthermore, adipogenic differentiation of MSCs was affected by addition of both ALN and 1,25(OH)2D3 to the media as confirmed by phenotype changes and lower number of lipid droplets. Finally, expression of adipogenic transcription factors and PPARγ2 activation were reduced in adipose differentiating MSCs treated with either ALN or ALN + 1,25(OH)2D3.

Conclusions: This study shows a potential anabolic effect of ALN in vitro through the stimulation of osteogenic differentiation of MSCs. Additionally, a previously unknown inhibitory effect of ALN on bone marrow adipogenesis was also found.
Osteogenic Potential of Postnatal Skeletal Muscle–Derived Stem Cells Is Influenced by Donor Sex
Authors: Corsi Karin A , Pollett Jonathan B , Phillippi Julie A , Usas Arvydas , Li Guangheng , Huard Johnny
Published: July 2007

This study compared the osteogenic differentiation of F-MDSCs and M-MDSCs. Interestingly, M-MDSCs expressed osteogenic markers and underwent mineralization more readily than F-MDSCs; a characteristic likely caused by more osteoprogenitor cells within the M-MDSCs than the F-MDSCs and/or an accelerated osteogenic differentiation of M-MDSCs.

Introduction: Although therapies involving stem cells will require both female and male cells, few studies have investigated whether sex-related differences exist in their osteogenic potential. Here, we compared the osteogenic differentiation of female and male mouse skeletal muscle–derived stem cells (F- and M-MDSCs, respectively), a potential cell source for orthopedic tissue engineering.

Materials and Methods: F- and M-MDSCs were stimulated with bone morphogenetic protein (BMP)4, followed by quantification of alkaline phosphatase (ALP) activity and expression of osteogenic genes. F- and M-MDSCs were also cultured as pellets in osteogenic medium to evaluate mineralization. Single cell–derived colonies of F- and M-MDSCs were stimulated with BMP4, stained for ALP, and scored as either Low ALP+ or High ALP+ to detect the presence of osteoprogenitor cells. F- and M-MDSCs were transduced with a BMP4 retrovirus (MDSC-BMP 4 cells) and used for the pellet culture and single cell–derived colony formation assays. As well, F- and M-MDSC -BMP 4 cells were implanted in the intramuscular pocket of sex-matched and sex-mismatched hosts, and bone formation was monitored radiographically.

Results and Conclusions: When stimulated with BMP4, both F- and M-MDSCs underwent osteogenic differentiation, although M-MDSCs had a significantly greater ALP activity and a larger increase in the expression of osteogenic genes than F-MDSCs. In the pellet culture assay, M-MDSCs showed greater mineralization than F-MDSCs. BMP4 stimulation of single cell–derived colonies from M-MDSCs showed higher levels of ALP than those from F-MDSCs. Similar results were obtained with the MDSC-BMP 4 cells. In vivo, F-MDSC -BMP 4 cells displayed variability in bone area and density, whereas M-MDSC -BMP 4 cells showed a more consistent and denser ectopic bone formation. More bone formation was also seen in male hosts compared with female hosts, regardless of the sex of the implanted cells. These results suggest that M-MDSCs may contain more osteoprogenitor cells than F-MDSCs, which may have implications in the development of cellular therapies for bone healing.
Evidence that the Localization of the Elongation Factor Spt16 Across Transcribed Genes Is Dependent Upon Histone H3 Integrity in Saccharomyces cerevisiae
Authors: Duina Andrea A , Rufiange Anne , Bracey John , Hall Jeffrey , Nourani Amine , Winston Fred
Published: July 2007

A previous study of histone H3 in Saccharomyces cerevisiae identified a mutant with a single amino acid change, leucine 61 to tryptophan, that confers several transcriptional defects. We now present several lines of evidence that this H3 mutant, H3-L61W, is impaired at the level of transcription elongation, likely by altered interactions with the conserved factor Spt16, a subunit of the transcription elongation complex yFACT. First, a selection for suppressors of the H3-L61W cold-sensitive phenotype has identified novel mutations in the gene encoding Spt16. These genetic interactions are allele specific, suggesting a direct interaction between H3 and Spt16. Second, similar to several other elongation and chromatin mutants, including spt16 mutants, an H3-L61W mutant allows transcription from a cryptic promoter within the FLO8 coding region. Finally, chromatin-immunoprecipitation experiments show that in an H3-L61W mutant there is a dramatically altered profile of Spt16 association over transcribed regions, with reduced levels over 5′-coding regions and elevated levels over the 3′ regions. Taken together, these and other results provide strong evidence that the integrity of histone H3 is crucial for ensuring proper distribution of Spt16 across transcribed genes and suggest a model for the mechanism by which Spt16 normally dissociates from DNA following transcription.
Inferring Somatic Mutation Rates Using the Stop-Enhanced Green Fluorescent Protein Mouse
Authors: Ro Simon , Rannala Bruce
Published: July 2007

A new method is developed for estimating rates of somatic mutation in vivo. The stop-enhanced green fluorescent protein (EGFP) transgenic mouse carries multiple copies of an EGFP gene with a premature stop codon. The gene can revert to a functional form via point mutations. Mice treated with a potent mutagen, N-ethyl-N-nitrosourea (ENU), and mice treated with a vehicle alone are assayed for mutations in liver cells. A stochastic model is developed to model the mutation and gene expression processes and maximum-likelihood estimators of the model parameters are derived. A likelihood-ratio test (LRT) is developed for detecting mutagenicity. Parametric bootstrap simulations are used to obtain confidence intervals of the parameter estimates and to estimate the significance of the LRT. The LRT is highly significant (α < 0.01) and the 95% confidence interval for the relative effect of the mutagen (the ratio of the rate of mutation during the interval of mutagen exposure to the rate of background mutation) ranges from a minimum 200-fold effect of the mutagen to a maximum 2000-fold effect.
Unraveling the Genetic Complexity of Drosophila stardust During Photoreceptor Morphogenesis and Prevention of Light-Induced Degeneration
Authors: Berger Sandra , Bulgakova Natalia A , Grawe Ferdi , Johnson Kevin , Knust Elisabeth
Published: July 2007

Drosophila Stardust, a membrane-associated guanylate kinase (MAGUK), recruits the transmembrane protein Crumbs and the cytoplasmic proteins DPATJ and DLin-7 into an apically localized protein scaffold. This evolutionarily conserved complex is required for epithelial cell polarity in Drosophila embryos and mammalian cells in culture. In addition, mutations in Drosophila crumbs and DPATJ impair morphogenesis of photoreceptor cells (PRCs) and result in light-dependent retinal degeneration. Here we show that stardust is a genetically complex locus. While all alleles tested perturb epithelial cell polarity in the embryo, only a subset of them affects morphogenesis of PRCs or induces light-dependent retinal degeneration. Alleles retaining particular postembryonic functions still express some Stardust protein in pupal and/or adult eyes. The phenotypic complexity is reflected by the expression of distinct splice variants at different developmental stages. All proteins expressed in the retina contain the PSD95, Discs Large, ZO-1 (PDZ), Src homology 3 (SH3), and guanylate kinase (GUK) domain, but lack a large region in the N terminus encoded by one exon. These results suggest that Stardust-based protein scaffolds are dynamic, which is not only mediated by multiple interaction partners, but in addition by various forms of the Stardust protein itself.
Molecular Differentiation at Nuclear Loci in French Host Races of the European Corn Borer (Ostrinia nubilalis)
Authors: Malausa Thibaut , Leniaud Laurianne , Martin Jean-François , Audiot Philippe , Bourguet Denis , Ponsard Sergine , Lee Siu-Fai , Harrison Richard G , Dopman Erik
Published: July 2007

French populations of the European corn borer consist of two sympatric and genetically differentiated host races. As such, they are well suited to study processes that could be involved in sympatric speciation, but the initial conditions of host-race divergence need to be elucidated. Gene genealogies can provide insight into the processes involved in speciation. We used DNA sequences of four nuclear genes to (1) document the genetic structure of the two French host races previously delineated with allozyme markers, (2) find genes directly or indirectly involved in reproductive isolation between host races, and (3) estimate the time since divergence of the two taxa and see whether this estimate is compatible with this divergence being the result of a host shift onto maize after its introduction into Europe ∼500 years ago. Gene genealogies revealed extensive shared polymorphism, but confirmed the previously observed genetic differentiation between the two host races. Significant departures from the predictions of neutral molecular evolution models were detected at three loci but were apparently unrelated to reproductive isolation between host races. Estimates of time since divergence between French host races varied from ∼75,000 to ∼150,000 years, suggesting that the two taxa diverged recently but probably long before the introduction of maize into Europe.
Concerted Evolution of rDNA in Recently Formed Tragopogon Allotetraploids Is Typically Associated With an Inverse Correlation Between Gene Copy Number and Expression
Authors: Matyášek Roman , Tate Jennifer A , Lim Yoong K , Šrubařová Hana , Koh Jin , Leitch Andrew R , Soltis Douglas E , Soltis Pamela S , Kovařík Aleš
Published: July 2007

We analyzed nuclear ribosomal DNA (rDNA) transcription and chromatin condensation in individuals from several populations of Tragopogon mirus and T. miscellus, allotetraploids that have formed repeatedly within only the last 80 years from T. dubius and T. porrifolius and T. dubius and T. pratensis, respectively. We identified populations with no (2), partial (2), and complete (4) nucleolar dominance. It is probable that epigenetic regulation following allopolyploidization varies between populations, with a tendency toward nucleolar dominance by one parental homeologue. Dominant rDNA loci are largely decondensed at interphase while silent loci formed condensed heterochromatic regions excluded from nucleoli. Those populations where nucleolar dominance is fixed are epigenetically more stable than those with partial or incomplete dominance. Previous studies indicated that concerted evolution has partially homogenized thousands of parental rDNA units typically reducing the copy numbers of those derived from the T. dubius diploid parent. Paradoxically, despite their low copy number, repeats of T. dubius origin dominate rDNA transcription in most populations studied, i.e., rDNA units that are genetic losers (copy numbers) are epigenetic winners (high expression).
Genetic Exchange Across a Species Boundary in the Archaeal Genus Ferroplasma
Authors: Eppley John M , Tyson Gene W , Getz Wayne M , Banfield Jillian F
Published: July 2007

Speciation as the result of barriers to genetic exchange is the foundation for the general biological species concept. However, the relevance of genetic exchange for defining microbial species is uncertain. In fact, the extent to which microbial populations comprise discrete clusters of evolutionarily related organisms is generally unclear. Metagenomic data from an acidophilic microbial community enabled a genomewide, comprehensive investigation of variation in individuals from two coexisting natural archaeal populations. Individuals are clustered into species-like groups in which cohesion appears to be maintained by homologous recombination. We quantified the dependence of recombination frequency on sequence similarity genomewide and found a decline in recombination with increasing evolutionary distance. Both inter- and intralineage recombination frequencies have a log-linear dependence on sequence divergence. In the declining phase of interspecies genetic exchange, recombination events cluster near the origin of replication and are localized by tRNAs and short regions of unusually high sequence similarity. The breakdown of genetic exchange with increasing sequence divergence could contribute to, or explain, the establishment and preservation of the observed population clusters in a manner consistent with the biological species concept.
Shs1 Plays Separable Roles in Septin Organization and Cytokinesis in Saccharomyces cerevisiae
Authors: Iwase Masayuki , Luo Jianying , Bi Erfei , Toh-e Akio
Published: July 2007

In Saccharomyces cerevisiae, five septins (Cdc3, Cdc10, Cdc11, Cdc12, and Shs1/Sep7) form the septin ring at the bud neck during vegetative growth. We show here that disruption of SHS1 caused cold-sensitive growth in the W303 background, with cells arrested in chains, indicative of a cytokinesis defect. Surprisingly, the other four septins appeared to form an apparently normal septin ring in shs1Δ cells grown under the restrictive condition. We found that Myo1 and Iqg1, two components of the actomyosin contractile ring, and Cyk3, a component of the septum formation, were either delocalized or mislocalized in shs1Δ cells, suggesting that Shs1 plays supportive roles in cytokinesis. We also found that deletion of SHS1 enhanced or suppressed the septin defect in cdc10Δ and cdc11Δ cells, respectively, suggesting that Shs1 is involved in septin organization, exerting different effects on septin-ring assembly, depending on the composition of the septin subunits. Furthermore, we constructed an shs1-100c allele that lacks the coding sequence for the C-terminal 32 amino acids. This allele still displayed the genetic interactions with the septin mutants, but did not show cytokinesis defects as described above, suggesting that the roles of Shs1 in septin organization and cytokinesis are separable.
Choline Transport and de novo Choline Synthesis Support Acetylcholine Biosynthesis in Caenorhabditis elegans Cholinergic Neurons
Authors: Mullen Gregory P , Mathews Eleanor A , Vu Mai H , Hunter Jerrod W , Frisby Dennis L , Duke Angie , Grundahl Kiely , Osborne Jamie D , Crowell John A , Rand James B
Published: July 2007

The cho-1 gene in Caenorhabditis elegans encodes a high-affinity plasma-membrane choline transporter believed to be rate limiting for acetylcholine (ACh) synthesis in cholinergic nerve terminals. We found that CHO-1 is expressed in most, but not all cholinergic neurons in C. elegans. cho-1 null mutants are viable and exhibit mild deficits in cholinergic behavior; they are slightly resistant to the acetylcholinesterase inhibitor aldicarb, and they exhibit reduced swimming rates in liquid. cho-1 mutants also fail to sustain swimming behavior; over a 33-min time course, cho-1 mutants slow down or stop swimming, whereas wild-type animals sustain the initial rate of swimming over the duration of the experiment. A functional CHO-1∷GFP fusion protein rescues these cho-1 mutant phenotypes and is enriched at cholinergic synapses. Although cho-1 mutants clearly exhibit defects in cholinergic behaviors, the loss of cho-1 function has surprisingly mild effects on cholinergic neurotransmission. However, reducing endogenous choline synthesis strongly enhances the phenotype of cho-1 mutants, giving rise to a synthetic uncoordinated phenotype. Our results indicate that both choline transport and de novo synthesis provide choline for ACh synthesis in C. elegans cholinergic neurons.
Epistasis Between Calpain 1 and Its Inhibitor Calpastatin Within Breeds of Cattle
Authors: Barendse W , Harrison B E , Hawken R J , Ferguson D M , Thompson J M , Thomas M B , Bunch R J
Published: July 2007

The calpain gene family and its inhibitors have diverse effects, many related to protein turnover, which appear to affect a range of phenotypes such as diabetes, exercise-induced muscle injury, and pathological events associated with degenerative neural diseases in humans, fertility, longevity, and postmortem effects on meat tenderness in livestock species. The calpains are inhibited by calpastatin, which binds directly to calpain. Here we report the direct measurement of epistatic interactions of causative mutations for quantitative trait loci (QTL) at calpain 1 (CAPN1), located on chromosome 29, with causative mutations for QTL variation at calpastatin (CAST), located on chromosome 7, in cattle. First we identified potential causative mutations at CAST and then genotyped these along with putative causative mutations at CAPN1 in >1500 cattle of seven breeds. The maximum allele substitution effect on the phenotype of the CAPN1:c.947G>C single nucleotide polymorphism (SNP) was 0.14 σp (P = 0.0003) and of the CAST:c.155C>T SNP was also 0.14 σp (P = 0.0011) when measured across breeds. We found significant epistasis between SNPs at CAPN1 and CAST in both taurine and zebu derived breeds. There were more additive × dominance components of epistasis than additive × additive and dominance × dominance components combined. A minority of breed comparisons did not show epistasis, suggesting that genetic variation at other genes may influence the degree of epistasis found in this system.
Hand-Washing and Diapering Equipment Reduces Disease Among Children in Out-of-Home Child Care Centers
Authors: Kotch Jonathan B. , Isbell Patricia , Weber David J. , Nguyen Viet , Savage Eric , Gunn Elizabeth , Skinner Martie , Fowlkes Stephen , Virk Jasveer , Allen Jonnell
Published: July 2007

OBJECTIVE. The objective of this study was to determine whether the installation of equipment for diaper-changing, hand-washing, and food preparation that is specifically designed to reduce the transmission of infectious agents would result in a decrease in the rate of diarrheal illness among children and their teachers in child care centers.

METHODS. Twenty-three pairs of child care centers were matched on size and star-rated license level. One member of each pair was randomly assigned to an intervention group and the other to a control group. Intervention centers received new diaper-changing, hand-washing, and food-preparation equipment, and both intervention and control centers received hygiene and sanitation training with reinforcement and follow-up as needed. Families with children in participating classrooms were called biweekly to ascertain the frequency and severity of any diarrheal illness episodes. Staff attendance was monitored, and staff hygiene and sanitation behaviors were observed and recorded monthly.

RESULTS. Although hygiene and sanitation behaviors improved in both intervention and control centers, there was a significant difference favoring the intervention centers with respect to frequency of diarrheal illness (0.90 vs 1.58 illnesses per 100 child-days in control centers) and proportion of days ill as a result of diarrhea (4.0% vs 5.0% in control centers) among the children. Staff in those same classrooms were reported to have a significantly lower proportion of days absent as a result of any illness (0.77% in treatment centers versus 1.73% in control centers).

CONCLUSION. Diapering, hand-washing, and food-preparation equipment that is specifically designed to reduce the spread of infectious agents significantly reduced diarrheal illness among the children and absence as a result of illness among staff in out-of-home child care centers.
Screening and Treatment for Lipid Disorders in Children and Adolescents: Systematic Evidence Review for the US Preventive Services Task Force
Authors: Haney Elizabeth M. , Huffman Laurie Hoyt , Bougatsos Christina , Freeman Michele , Steiner Robert D. , Nelson Heidi D.
Published: July 2007

OBJECTIVE. This was a systematic evidence review for the US Preventive Services Task Force, intended to synthesize the published evidence regarding the effectiveness of selecting, testing, and managing children and adolescents with dyslipidemia in the course of routine primary care.

METHODS. Literature searches were performed to identify published articles that addressed 10 key questions. The review focused on screening relevant to primary care of children without previously identified dyslipidemias, but included treatment trials of children with dyslipidemia because some drugs have only been tested in that population.

RESULTS. Normal values for lipids for children and adolescents are defined according to population levels (percentiles). Age, gender, and racial differences and temporal trends may alter these statistical cut points. Approximately 40% to 55% of children with elevated total cholesterol and low-density lipoprotein levels will continue to have elevated lipid levels on follow-up. Current screening recommendations based on family history will fail to detect substantial numbers (30%–60%) of children with elevated lipid levels. Drug treatment for dyslipidemia in children has been studied and shown to be effective only for suspected or proven familial monogenic dyslipidemias. Intensive dietary counseling and follow-up can result in improvements in lipid levels, but these results have not been sustained after the cessation of the intervention. The few trials of exercise are of fair-to-poor quality and show little or no improvements in lipid levels for children without monogenic dyslipidemias. Although reported adverse effects were not serious, studies were generally small and not of sufficient duration to determine long-term effects of either short or extended use.

CONCLUSIONS. Several key issues about screening and treatment of dyslipidemia in children and adolescents could not be addressed because of lack of studies, including effectiveness of screening on adult coronary heart disease or lipid outcomes, optimal ages and intervals for screening children, or effects of treatment of childhood lipid levels on adult coronary heart disease outcomes.
Self-Reported Health Status and Health-Related Quality of Life of Teenagers Who Were Born Before 29 Weeks' Gestational Age
Authors: Gray Ron , Petrou Stavros , Hockley Christine , Gardner Frances
Published: July 2007

OBJECTIVE. The objective of this study was to describe the self-reported health status and health-related quality of life of British teenagers who are in mainstream schooling and were born before 29 weeks' gestational age compared with British teenagers who were born at term.

METHODS. All surviving children who were born at <29 weeks' gestation in the former Northern Region of England in 1983 and in the former Oxford Region of England and in Scotland in 1984 were eligible. A comparison group of teenagers who were born at term were also recruited. Children's responses to the Health Utilities Index Mark III were compared.

RESULTS. A total of 218 of the original 535 children who were born in the 3 regions during the study period were alive at 15 to 16 years of age. A complete Health Utilities Index Mark III record was available for 140 children in mainstream schools and for 108 control subjects. In 7 of the 8 attributes (vision, hearing, speech, emotion, pain, ambulation, and dexterity), there were no statistically significant differences in any functional impairment between the comparator groups. However, the preterm group did report a higher level of functional impairment in the cognition attribute (40.7% vs 25.0%). Although there was no difference in the median Health Utilities Index Mark III utility score between the 2 groups (0.93), there was a broader range of utility scores for the preterm group (0.07–1.0 vs 0.45–1.0 for the control group).

CONCLUSIONS. Despite objective evidence that children and teenagers who were born preterm have poorer health on average than term-born control subjects, this is not reflected in their own ratings of their health status and health-related quality of life at 15 to 16 years of age. The reasons for these differences need to be further explored.
Parental Ability to Discriminate the Weight Status of Children: Results of a Survey
Authors: Huang Jeannie S. , Becerra Karen , Oda Thaghar , Walker Edward , Xu Ronghui , Donohue Michael , Chen Iris , Curbelo Violeta , Breslow Adam
Published: July 2007

OBJECTIVES. In this study we aimed to explore parents' weight perceptions of their children and of unrelated children.

METHODS. Parents of children ≤18 years of age who were attending pediatric clinics throughout San Diego County, California, were surveyed concerning their children's weight status and the weight status of unrelated children in various age groups. Height and weight were measured, and weight status was determined for both the parent and child. The influence of various demographic variables on parents' weight perceptions and the relationship between parents' perceptions of weight of their children and parents' perceptions of weight of unrelated children were evaluated. Multivariate regression modeling was applied to identify predictors of parents' perceptions of weight of their own children.

RESULTS. Of 1098 parents surveyed, 87% were women, 74% were white, and 46% reported Hispanic ethnicity. Seventy percent of the parents surveyed were overweight or obese, and 39% of their children were at risk for overweight or overweight. Sixty-one percent of parents correctly identified their children's weight status, and parents were able to correctly identify the weight status of unrelated children in 58% of reviewed photographs. Parents' weight perceptions of their children were not related to their ability to determine the weight status of unrelated children or to their ideal weight selections among unrelated children. In a multivariate logistic regression analysis, parental ability to correctly assess their child's weight status was associated with their child's age and weight status.

CONCLUSIONS. Parents' perceptions of their own children's weight status are influenced by their children's characteristics and do not seem to correspond with their weight perceptions of unrelated children. Parental recognition of weight issues in their offspring may be impeded by their inability to apply criteria used to ascertain the weight status of unrelated children to their own children.