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Fertile
Terms modified by Fertile Selected AbstractsHow Fertile Is an RRC-EM Visit?ACADEMIC EMERGENCY MEDICINE, Issue 7 2005James E. Olson Ph.D. No abstract is available for this article. [source] Disease resistance conferred by the expression of a gene encoding a synthetic peptide in transgenic cotton (Gossypium hirsutum L.) plantsPLANT BIOTECHNOLOGY JOURNAL, Issue 6 2005Kanniah Rajasekaran Summary Fertile, transgenic cotton plants expressing the synthetic antimicrobial peptide, D4E1, were produced through Agrobacterium -mediated transformation. PCR products and Southern blots confirmed integration of the D4E1 gene, while RT-PCR of cotton RNA confirmed the presence of D4E1 transcripts. In vitro assays with crude leaf protein extracts from T0 and T1 plants confirmed that D4E1 was expressed at sufficient levels to inhibit the growth of Fusarium verticillioides and Verticillium dahliae compared to extracts from negative control plants transformed with pBI-d35S,- uidA-nos (CGUS). Although in vitro assays did not show control of pre-germinated spores of Aspergillus flavus, bioassays with cotton seeds in situ or in planta, inoculated with a GFP-expressing A. flavus, indicated that the transgenic cotton seeds inhibited extensive colonization and spread by the fungus in cotyledons and seed coats. In planta assays with the fungal pathogen, Thielaviopsis basicola, which causes black root rot in cotton, showed typical symptoms such as black discoloration and constriction on hypocotyls, reduced branching of roots in CGUS negative control T1 seedlings, while transgenic T1 seedlings showed a significant reduction in disease symptoms and increased seedling fresh weight, demonstrating tolerance to the fungal pathogen. Significant advantages of synthetic peptides in developing transgenic crop plants that are resistant to diseases and mycotoxin-causing fungal pathogens are highlighted in this report. [source] Molecular mapping of a fertility restorer gene for cytoplasmic male sterility in soybeanPLANT BREEDING, Issue 1 2010Y. Wang With 2 figures and 2 tables Abstract In this study, we report the mapping of the Rf locus in soybean by microsatellite simple sequence repeat (SSR) genetic markers. A cross was made between cytoplasmic male sterility (CMS) line JLCMS82A and restorer line JIHUI 1 based on the DNA polymorphisms revealed by 109 SSR markers. A F2 population derived from a single F1 plant containing 103 individuals was used for mapping the Rf locus. The Rf gene of JIHUI 1 gametophytically restores male fertility to JLCMS82A. Fertile and semi-fertile DNA bulks and parental DNAs were screened with 219 SSR markers, and Satt215 which was previously mapped to soybean LG J, was found linked to the Rf gene. Five additional polymorphic SSR markers from LG J were used for analysis and a regional linkage map around the Rf locus was established. SSR markers, Sctt011 and Satt547, flanked the Rf locus at 3.6 cM and 5.4 cM, respectively. The availability of these SSR markers will facilitate the selection of restorer lines in hybrid soybean breeding. [source] Fascin1 is dispensable for mouse development but is favorable for neonatal survivalCYTOSKELETON, Issue 8 2009Yoshihiko Yamakita Abstract Fascin1, an actin-bundling protein, has been demonstrated to be critical for filopodia formation in cultured cells, and thus is believed to be vital in motile activities including neurite extension and cell migration. To test whether fascin1 plays such essential roles within a whole animal, we have generated and characterized fascin1-deficient mice. Unexpectedly, fascin1-deficient mice are viable and fertile with no major developmental defect. Nissl staining of serial coronal brain sections reveals that fascin1-deficient brain is grossly normal except that knockout mouse brain lacks the posterior region of the anterior commissure neuron and has larger lateral ventricle. Fascin1-deficient, dorsal root ganglion neurons are able to extend neurites in vitro as well as those from wild-type mice, although fascin1-deficient growth cones are smaller and exhibit fewer and shorter filopodia than wild-type counterparts. Likewise, fascin1-deficient, embryonic fibroblasts are able to assemble filopodia, though filopodia are fewer, shorter and short-lived. These results indicate that fascin1-mediated filopodia assembly is dispensable for mouse development. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] Organization Structure from a Loose Coupling Perspective: A Multidimensional Approach,DECISION SCIENCES, Issue 2 2001Rafik I. Beekun Abstract Organizational theories frequently rely on notions of sharing and dependence among organizational participants, but researchers usually focus on characteristics of the actors themselves instead of the relational patterns among the actors. Loose coupling is one conceptual tool that emphasizes relational patterns. Loose coupling, however, is an abstract metaphor that is simultaneously fertile and ambiguous. This paper develops a rigorous and comprehensive framework that sharpens the theoretical contributions of loose coupling to our understanding of structural relationships. Characteristics of loose coupling capture some important and underexplored features of multidimensional fit and interdependence in organizations. The proposed framework clarifies these theoretical contributions of loose coupling with concepts and equations modified from network analysis. Testable hypotheses are proposed with respect to three key independent variables that may affect patterns of coupling: organization strategy, technology, and environmental turbulence. Additional hypotheses are advanced with respect to the use of the multidimensional approach to loose coupling in studying new organizational forms. Initial psychometric and empirical evidence are presented. [source] Generation and characterization of a novel neural crest marker allele, Inka1-LacZ, reveals a role for Inka1 in mouse neural tube closureDEVELOPMENTAL DYNAMICS, Issue 4 2010Bethany S. Reid Abstract Previous studies identified Inka1 as a gene regulated by AP-2, in the neural crest required for craniofacial morphogenesis in fish and frog. Here, we extend the analysis of Inka1 function and regulation to the mouse by generating a LacZ knock-in allele. Inka1-LacZ allele expression occurs in the cephalic mesenchyme, heart, and paraxial mesoderm prior to E8.5. Subsequently, expression is observed in the migratory neural crest cells and their derivatives. Consistent with expression of Inka1 in tissues of the developing head during neurulation, a low percentage of Inka1,/, mice show exencephaly while the remainder are viable and fertile. Further studies indicate that AP-2, is not required for Inka1 expression in the mouse, and suggest that there is no significant genetic interaction between these two factors during embryogenesis. Together, these data demonstrate that while the expression domain of Inka1 is conserved among vertebrates, its function and regulation are not. Developmental Dynamics 239:1188,1196, 2010. © 2010 Wiley-Liss, Inc. [source] Gene targeted ablation of high molecular weight fibroblast growth factor-2DEVELOPMENTAL DYNAMICS, Issue 2 2009Mohamad Azhar Abstract Fibroblast growth factor-2 (FGF2) is produced as high molecular weight isoforms (HMW) and a low molecular weight isoform (LMW) by means of alternative usage of translation start sites in a single Fgf2 mRNA. Although the physiological function of FGF2 and FGF2 LMW has been investigated in myocardial capillarogenesis during normal cardiac growth, the role of FGF2 HMW has not been determined. Here, we report the generation of FGF2 HMW-deficient mice in which FGF2 HMW isoforms are ablated by the Tag-and-Exchange gene targeting technique. These mice are normal and fertile with normal fecundity, and have a normal life span. Histological, immunohistochemical, and morphometric analyses indicate normal myocardial architecture, blood vessel, and cardiac capillary density in young adult FGF2 HMW-deficient mice. These mice along with the FGF2- and FGF2 LMW-deficient mice that we have generated previously will be very useful for elucidating the differential functions of FGF2 isoforms in pathophysiology of cardiovascular diseases. Developmental Dynamics 238:351,357, 2009. © 2008 Wiley-Liss, Inc. [source] Zinc-finger paralogues tsh and tio are functionally equivalent during imaginal development in Drosophila and maintain their expression levels through auto- and cross-negative feedback loopsDEVELOPMENTAL DYNAMICS, Issue 1 2009José Bessa Abstract teashirt (tsh) and tiptop (tio) are two Drosophila gene paralogues encoding zinc-finger transcription factors. While tsh is an important developmental regulator, tio null individuals are viable and fertile. Here, we show that tio and tsh have coincident expression domains in the imaginal discs, the precursors of the adult body, and that both genes show similar functional properties when expressed ectopically. Furthermore, tio is able to rescue the development of tsh mutants, indicating that both genes are functionally equivalent during imaginal development. Of interest, the transcriptional regulation of tio and tsh is linked by a negative feedback loop. This mechanism might be required to maintain a tight control on the total levels of tio/tsh and could help explaining why Drosophila keeps an apparently dispensable gene. Developmental Dynamics 238:19,28, 2009. © 2008 Wiley-Liss, Inc. [source] Shb null allele is inherited with a transmission ratio distortion and causes reduced viability in uteroDEVELOPMENTAL DYNAMICS, Issue 9 2007Vitezslav Kriz Abstract SHB is an Src homology 2 domain-containing adapter protein that has been found to be involved in numerous cellular responses. We have generated an Shb knockout mouse. No Shb,/, pups or embryos were obtained on the C57Bl6 background, indicating an early defect as a consequence of Shb - gene inactivation on this genetic background. Breeding heterozygotes for Shb gene inactivation (Shb+/,) on a mixed genetic background (FVB/C57Bl6/129Sv) reveals a distorted transmission ratio of the null allele with reduced numbers of Shb+/+ and Shb,/, animals, but increased number of Shb+/, animals. The Shb, allele is associated with various forms of malformations, explaining the relative reduction in the number of Shb,/, offspring. Shb,/, animals that were born were viable, fertile, and showed no obvious defects. However, Shb+/, female mice ovulated preferentially Shb, oocytes explaining the reduced frequency of Shb+/+ mice. Our study suggests a role of SHB during reproduction and development. Developmental Dynamics 236:2485,2492, 2007. © 2007 Wiley-Liss, Inc. [source] A comparative analysis of the habitat of the extinct aurochs and other prehistoric mammals in BritainECOGRAPHY, Issue 2 2008Stephen J. G. Hall The present study tests the hypothesis that the habitat of the globally extinct aurochs Bos primigenius was primarily riverine flat-lands. Landscape features in Britain were analyzed for sites with Late Pleistocene and postglacial finds of aurochs (n=188), and, for comparison, wolf (101), brown bear (96), red deer (73), beaver (68), roe deer (46) and moose (23). Find sites were defined as Ordnance Survey 1 km map squares containing 1 or more finds. For each, spot height above sea level, heights of contour lines, flatness of terrain, total length of watercourses, and presence of woods, rock and water features were noted. Comparisons of find sites among species (Kruskal-Wallis test) show significant differences that accord with knowledge of present-day habitat preferences at the landscape level. Considering the species separately each find site was then compared with a randomly selected control map square within 10 km. Compared with their respective control squares, find sites of beaver have, today, a stronger association with presence of lakes; those of brown bear and wolf with presence of cliffs and rock outcrops; and those of aurochs with absence of woodland and with lower elevation and greater flatness. The concordance of these findings with the present-day habitats of the extant species suggests valid inferences can be made about the habitat preference of the extinct aurochs. On this basis the aurochs appears, as hypothesized, to have selected low-lying, flat ground, which (indicated by its present-day use for purposes other than woodland) was relatively fertile. [source] Oviposition preferences of Maculinea alcon as influenced by aphid (Aphis gentianae) and fungal (Puccinia gentianae) infestation of larval host plantsECOLOGICAL ENTOMOLOGY, Issue 1 2009ERVIN ÁRNYAS Abstract 1.,The influence of infestation of the larval host plant Gentiana cruciata on the egg-laying preferences of the xerophilous ecotype of Alcon Blue butterfly (Maculinea alcon) was studied in a semi-dry grassland area (Aggtelek Karst Region, Northern Hungary). 2.,We examined whether oviposition patterns of females differed when G. cruciata stems were uninfested compared with when they were infested by an aphid (Aphis gentianae) or a rust (Puccinia gentianae) species. 3.,Females laid more than 90% of their eggs on fertile, uninfested G. cruciata stems, although these stems comprised only , 50% of the total stems available. Stems infested by aphids were similar to uninfested ones in properties that had a strong correlation with egg numbers, and yet there were significantly fewer eggs on infested stems than on intact ones. 4.,Females never laid eggs on parts of Gentiana stems infested by aphids, and the presence of Lasius paralienus ants, which have a mutualistic interaction with Aphis gentianae, did not increase the repulsive effect of aphids. Infection of Gentiana by Puccinia did not influence the egg-laying behaviour of females, even though the flowers and buds of infested stems exhibited a delayed development. 5.,Aphid infestation can influence butterfly oviposition patterns through both direct and indirect effects. The presence of aphids directly excluded oviposition, but our data also indicated the possibility of an indirect effect of aphid infestation. Stems that had no aphids at the last egg counting, but were infested prior to it, had significantly fewer eggs than those that were never infested. [source] Antioxidants, showy males and sperm qualityECOLOGY LETTERS, Issue 5 2001Jonathan D. Blount The fertility of males sometimes correlates with their ornamental display, but we do not have a mechanistic explanation to universally link these traits. We suggest that both sperm quality (fertility; integrity of DNA), and the substrates responsible for male ornamentation, may be vulnerable to free radical attack, which can be mitigated by antioxidants. Support for these ideas is at present weak, and requires validation in ecological contexts. We hypothesize that a link between ornamentation and sperm quality could arise if antioxidants are in limited supply, and the showiest males may be preferred because they are most likely to be fertile, or to provide sperm with undamaged genotypes that could give rise to fit offspring. [source] Anti-Predator Signals as Advertisements: Evidence in White-Throated Magpie-JaysETHOLOGY, Issue 6 2009Jesse M. S. Ellis Calls and displays elicited by predators usually function as alarms or to inform predators of their detection. However, predator encounters may afford some individuals the opportunity to demonstrate quality or signal their availability. Here, I report on a class of vocal signals produced in predator-elicited displays that share many characteristics with sexually selected song. White-throated magpie-jays (Calocitta formosa) display at low-threat predators while producing ,loud display calls' (LDCs). I use this term because the calls occur primarily in two display contexts (see below) though occasionally in other contexts as well. Such calls and displays are primarily produced by males, and also occur in one other context, at dawn. Playback experiments showed that despite being elicited by predators, males were more likely than females to respond to LDCs, and more likely to respond when their mate was fertile. Over 134 different call types were produced in over 200 displays by 34 males; the largest minimum repertoire size was 67. Presentations of taxidermic raptor mounts elicited some LDCs, but fewer calls and lower diversity than at dawn or in predator approach displays. The male bias and high diversity suggest that LDCs are an outcome of intersexual selection, while their elicitation by predators suggests an alarm function. I propose that male magpie-jays use predator encounters as opportunities to advertise their presence and availability as mates; they use LDCs as songs. Such a communication system seems to have been favored by the unusual social system of magpie-jays, in which female groups defend territories and males have little opportunity to defend resources for mate attraction, forcing them to advertise when females are paying the most attention, during predator encounters. [source] Boredom, "Trouble," and the Realities of Postcolonial Reservation LifeETHOS, Issue 1 2003Assistant professor Lori L. Jervis Perhaps because of its reputation as an inconsequential emotion, the significance of boredom in human social life has often been minimized if not ignored. Boredom has been theoretically linked to modernity, affluence, and the growing problem of filling "leisure time. "It has also been attributed to the expansion of individualism with its heightened expectations of personal gratification. Whether a reaction to the sensation ofunderstimulation or "overload," boredom appears to be, ultimately, a problem of meaning. In this article, we consider the applicability of these notions to the contemporary American Indian reservation context, examining discourse about boredom as expressed in interviews with members of a northern plains tribe. Of special interest is how boredom figures into the phenomenon of "trouble" (e.g., alcohol and drug abuse, violence, and illegal activities). Although boredom is certainly familiar to various strata of contemporary U.S. society,and arguably part of what it means to be human,we propose that the realities of postcolonial reservation life provide an especially fertile and undertheorized breeding ground for this condition, and our examination of the relationship between boredom and trouble suggests that boredom's implications for both individual subjectivity and group sociality are far from trivial. [source] PHYLOGENETIC PLACEMENT OF AN UNUSUAL CORAL MUSHROOM CHALLENGES THE CLASSIC HYPOTHESIS OF STRICT COEVOLUTION IN THE APTEROSTIGMA PILOSUM GROUP ANT,FUNGUS MUTUALISMEVOLUTION, Issue 8 2009Bryn T. M. Dentinger The ,50 million-year-old fungus-farming ant mutualism is a classic example of coevolution, involving ants that subsist on asexual, fungal biomass, in turn propagating the fungus clonally through nest-to-nest transmission. Most mutualistic ants cultivate two closely related groups of gilled mushrooms, whereas one small group of ants in the genus Apterostigma cultivates a distantly related lineage comprised of the G2 and G4 groups. The G2 and G4 fungi were previously shown to form a monophyletic group sister to the thread-like coral mushroom family Pterulaceae. Here, we identify an enigmatic coral mushroom that produces both fertile and sterile fruiting structures as the closest free-living relative of the G4 fungi, challenging the monophyly of the Apterostigma -cultivated fungi for the first time. Both nonparametric bootstrap and Bayesian posterior probability support the node leading to the G4 cultivars and a free-living Pterula mushroom. These data suggest three scenarios that contradict the hypothesis of strict coevolution: (1) multiple domestications, (2) escape from domestication, (3) selection of single cultivar lineages from an ancestral mixed-fungus garden. These results illustrate how incomplete phylogenies for coevolved symbionts impede our understanding of the patterns and processes of coevolution. [source] EXPERIMENTAL MANIPULATION OF SEXUAL SELECTION PROMOTES GREATER MALE MATING CAPACITY BUT DOES NOT ALTER SPERM INVESTMENTEVOLUTION, Issue 4 2009Helen S. Crudgington Sexual selection theory makes clear predictions regarding male spermatogenic investment. To test these predictions we used experimental sexual selection in Drosophila pseudoobscura, a sperm heteromorphic species in which males produce both fertile and sterile sperm, the latter of which may function in postmating competition. Specifically, we determined whether the number and size of both sperm types, as well as relative testis mass and accessory gland size, increased with increased sperm competition risk and whether any fitness benefits could accrue from such changes. We found no effect of sexual selection history on either the number or size of either sperm morph, or on relative testis mass. However, males experiencing a greater opportunity for sexual selection evolved the largest accessory glands, had the greatest mating capacity, and sired the most progeny. These findings suggest that sterile sperm are not direct targets of sexual selection and that accessory gland size, rather than testis mass, appears to be an important determinant of male reproductive success. We briefly review the data from experimental sexual selection studies and find that testis mass may not be a frequent target of postcopulatory sexual selection and, even when it is, the resulting changes do not always improve fitness. [source] FREQUENCY AND SPATIAL PATTERNING OF CLONAL REPRODUCTION IN LOUISIANA IRIS HYBRID POPULATIONSEVOLUTION, Issue 1 2000John M. Burke Abstract., The plant genera in which natural hybridization is most prevalent tend to be outcrossing perennials with some mechanism for clonal (i.e., asexual) reproduction. Although clonal reproduction in fertile, sexually reproducing hybrid populations could have important evolutionary consequences, little attention has been paid to quantifying this parameter in such populations. In the present study, we examined the frequency and spatial patterning of clonal reproduction in two Louisiana iris hybrid populations. Allozyme analysis of both populations revealed relatively high levels of genotypic diversity. However, a considerable amount of clonality was apparent. Nearly half of all genets (47%) in one population and more than half (61%) in the other had multiple ramets. Furthermore, both populations exhibited relatively high levels of genetic structuring, a pattern that resulted from the aggregation of clonal ramets. The occurrence of clonal reproduction in hybrid populations could not only facilitate introgression through an increase in the number of flowering ramets per genet and/or the survivorship of early generation hybrids, but might also influence the mating system of such populations. Any potential increase in the selfing rate due to cross-pollination among ramets of the same genet may, in turn, increase the likelihood of homoploid hybrid speciation. [source] Deficits in acetylcholine homeostasis, receptors and behaviors in choline transporter heterozygous miceGENES, BRAIN AND BEHAVIOR, Issue 5 2007M. H. Bazalakova Cholinergic neurons elaborate a hemicholinium-3 (HC-3) sensitive choline transporter (CHT) that mediates presynaptic, high-affinity choline uptake (HACU) in support of acetylcholine (ACh) synthesis and release. Homozygous deletion of CHT (,/,) is lethal shortly after birth (Ferguson et al. 2004), consistent with CHT as an essential component of cholinergic signaling, but precluding functional analyses of CHT contributions in adult animals. In contrast, CHT+/, mice are viable, fertile and display normal levels of synaptosomal HACU, yet demonstrate reduced CHT protein and increased sensitivity to HC-3, suggestive of underlying cholinergic hypofunction. We find that CHT+/, mice are equivalent to CHT+/+ siblings on measures of motor co-ordination (rotarod), general activity (open field), anxiety (elevated plus maze, light/dark paradigms) and spatial learning and memory (Morris water maze). However, CHT+/, mice display impaired performance as a result of physical challenge in the treadmill paradigm, as well as reduced sensitivity to challenge with the muscarinic receptor antagonist scopolamine in the open field paradigm. These behavioral alterations are accompanied by significantly reduced brain ACh levels, elevated choline levels and brain region-specific decreased expression of M1 and M2 muscarinic acetylcholine receptors. Our studies suggest that CHT hemizygosity results in adequate baseline ACh stores, sufficient to sustain many phenotypes, but normal sensitivities to physical and/or pharmacological challenge require full cholinergic signaling capacity. [source] A unique expression pattern of Tbx10 in the hindbrain as revealed by Tbx10LacZ alleleGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 5 2010Xiao Dong Xue To study the expression/function of Tbx10, a T-box gene, Tbx10LacZ/+ mice were established by replacing the T-box coding region with a LacZ gene. X-gal staining showed that LacZ+ cells were localized to two-cell populations in rhombomere 4 and rhombomere 6. No significant differences in the locations of LacZ+ cells were found between Tbx10LacZ/+ and Tbx10LacZ/LacZ mice, and the Tbx10LacZ/LacZ mice were viable and fertile. We found that the LacZ+ cells are present in both embryonic and adult mice. Histological studies suggest that the rhombomere 4-derived LacZ+ cells are a subpopulation of the ventral interneurons in the pons. [source] Dual fluorescent protein reporters for studying cell behaviors in vivoGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 10 2009M. David Stewart Abstract Fluorescent proteins (FPs) are useful tools for visualizing live cells and their behaviors. Protein domains that mediate subcellular localization have been fused to FPs to highlight cellular structures. FPs fused with histone H2B incorporate into chromatin allowing visualization of nuclear events. FPs fused to a glycosylphosphatidylinositol anchor signal sequence label the plasma membrane, highlighting cellular shape. Thus, a reporter gene containing both types of FP fusions would allow for effective monitoring of cell shape, movement, mitotic stage, apoptosis, and other cellular activities. Here, we report a binary color-coding system using four differently colored FP reporters that generates 16 distinct color codes to label the nuclei and plasma membranes of live cells in culture and in transgenic mice. As an initial test of this system in vivo, the promoter of the human Ubiquitin C (UBC) gene was used to widely express one of the color-code reporters. Widespread expression of the reporter was attained in embryos; however, both male and female transgenic mice were infertile. In contrast, the promoter of the mouse Oct4/Pou5f1 gene linked to two different color-code reporters specifically labeled blastocysts, primordial germ cells, and postnatal germ cells, and these mice were fertile. Time-lapse movies of fluorescently-labeled primordial germs cells demonstrate the utility of the color-code system to visualize cell behaviors. This set of new FP reporters should be a useful tool for labeling distinct cell populations and studying their behaviors in complex tissues in vivo. genesis 47:708,717, 2009. © 2009 Wiley-Liss, Inc. [source] Sfrp5 is not essential for axis formation in the mouse,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 12 2006Irina Leaf Abstract Secreted frizzled related protein (Sfrp) genes encode extracellular factors that can modulate Wnt signaling. During early post-implantation mouse development Sfrp5 is expressed in the anterior visceral endoderm (AVE) and the ventral foregut endoderm. The AVE is important in anterior,posterior axis formation and the ventral foregut endoderm contributes to multiple gut tissues. Here to determine the essential role of Sfrp5 in early mouse development we generated Sfrp5 -deficient mice by gene targeting. We report that Sfrp5 -deficient mice are viable and fertile. To determine whether the absence of an axis phenotype might be due to genetic redundancy with Dkk1 in the AVE we generated Sfrp5;Dkk1 double mutant mice. AVE development and primitive streak formation appeared normal in Sfrp5,/,;Dkk1,/, embryos. These results indicate that Sfrp5 is not essential for axis formation or foregut morphogenesis in the mouse and also imply that Sfrp5 and Dkk1 together are not essential for AVE development. genesis 44:573,578, 2006. Published 2006 Wiley-Liss, Inc. [source] Floxed allele for conditional inactivation of the GABAB(1) geneGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 3 2004Corinne Haller Abstract GABAB receptors are the G-protein-coupled receptors for the neurotransmitter GABA. GABAB receptors are broadly expressed in the nervous system. Their complete absence in mice causes premature lethality or,when mice are viable,epilepsy, impaired memory, hyperalgesia, hypothermia, and hyperactivity. A spatially and temporally restricted loss of GABAB function would allow addressing how the absence of GABAB receptors leads to these diverse phenotypes. To permit a conditional gene inactivation, we flanked critical exons of the GABAB(1) gene with lox511 sites. GABAB(1)lox511/lox511 mice exhibit normal levels of GABAB(1) protein, are fertile, and do not display any behavioral phenotype. We crossed GABAB(1)lox511/lox511 with Cre-deleter mice to produce mice with an unrestricted GABAB receptor elimination. These GABAB(1),/, mice no longer synthesize GABAB(1) protein and exhibit the expected behavioral abnormalities. The conditional GABAB(1) allele described here is therefore suitable for generating mice with a site- and time-specific loss of GABAB function. genesis 40:125,130, 2004. © 2004 Wiley-Liss, Inc. [source] Comparison between computerized slow-stage and static liquid nitrogen vapour freezing methods with respect to the deleterious effect on chromatin and morphology of spermatozoa from fertile and subfertile menINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2001M. E. Hammadeh The purpose of this study was to determine the negative effects (cryodamage) on human spermatozoa after freeze-thawing and to determine whether freeze-thawing of spermatozoa with a programmed slow freezer is better than freezing with liquid nitrogen vapour (rapid freezing) with regard to alterations in sperm chromatin and morphology in semen from fertile (donor) and subfertile, IVF/ICSI, patients. Ninety-five semen samples were obtained either from patients attending our IVF unit for treatment (n=34) or from donors (n=25) with proven fertility and normal sperm quality according to WHO guidelines. Each semen sample was divided into two parts after liquefaction and addition of the cryoprotectant. The first part was frozen using a programmed biological freezer and the second part was frozen by means of liquid nitrogen vapour. Smears were made before the freezing and after the thawing procedure to assess morphology (strict criteria) and chromatin condensation (Acridine Orange test). The mean percentage of chromatin condensed spermatozoa in the samples from donors (control group) was 92.4 ± 8.4% before freezing and this decreased significantly (p < 0.0001) to 88.7 ± 11.2% after freeze-thawing with the computerized slow-stage freezer and to 87.2 ± 12.3% after using static liquid nitrogen vapour (p < 0.001). The corresponding values for semen obtained from patients was 78.9 ± 10.3% before freezing which decreased to 70.7 ± 10.8 and 68.5 ± 14.8%, respectively (p < 0.001). On the other hand, the mean percentage of normal sperm morphology in the control group decreased from 26.3 ± 7.5% before freezing to 22.1 ± 6.4% (p < 0.0001) after thawing with the computerized slow-stage freezer and to 22.2 ± 6.6% (p < 0.0001) after the use of static liquid nitrogen vapour. In the patient group, the mean percentage of normal morphology decreased from 11.7 ± 6.1% after freezing with the biological freezer to 9.3 ± 5.6% and to 8.0 ± 4.9% after freezing with static liquid nitrogen vapour. This study demonstrates that chromatin packaging and morphology of human spermatozoa decrease significantly after the freeze-thawing procedure, not only after the use of static liquid nitrogen vapour but also after the use of a computerized slow-stage freezer. However, the chromatin of semen samples with normal semen parameters (donor sperm) withstand the freeze-thaw injury better than those with low quality semen samples. Therefore, the computerized slow stage freezer could be recommended for freezing of human spermatozoa, especially for subnormal semen samples, for example, ICSI and ICSI/TESE candidates and from patients with testicular tumours or Hodgkin's disease, in order to avoid further damage to the sperm chromatin structure. [source] Aquatic Microbial Ecology: Water Desert, Microcosm, Ecosystem.INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 4-5 2008What's Next? Abstract Aquatic microbial ecology aims at nothing less than explaining the world from "ecological scratch". It develops theories, concepts and models about the small and invisible living world that is at the bottom of every macroscopic aquatic system. In this paper we propose to look at the development of Aquatic Microbial Ecology as a reiteration of classical (eukaryotic) limnology and oceanography. This was conceptualized moving historically from the so-called water desert to microcosm to ecosystem. Each of these concepts characterizes a particular historical field of knowledge that embraces also practices and theories about living beings in aquatic environments. Concerning the question of "who is there", however, Aquatic Microbial Ecology historically developed in reverse order. Repetition, reiteration and replication notwithstanding, Aquatic Microbial Ecology has contributed new ideas, theories and methods to the whole field of ecology as well as to microbiology. The disciplining of Aquatic Microbial Ecology happened in the larger field of plankton biology, and it is still attached to this biological domain, even conceiving of itself very self-consciously as a discipline of its own. Today, Aquatic Microbial Ecology as a discipline is much broader than plankton ecology ever was, for it includes not only oceans and freshwaters but also benthic, interstitial and groundwater systems. The success of Aquatic Microbial Ecology is expressed by its influence on other fields in ecology. The challenge is to further develop its theoretical and methodological features while at the same time contributing to current pressing problems such as climate change or the management of global water resources. And then it may not be fanciful to suppose that even in the year nineteen hundred and nineteen a great number of minds are still only partially lit up by the cold light of knowledge. It is the most capricious illuminant. They are still apt to ruminate, without an overpowering bias to the truth, whether a kingfisher's body shows which way the wind blows; whether an ostrich digests iron; whether owls and ravens herald ill-fortune; and the spilling of salt bad luck; what the tingling of ears forebodes, and even to toy pleasantly with more curious speculations as to the joints of elephants and the politics of storks, which came within the province of the more fertile and better-informed brain of the author (1919) Virginia Woolf from the essay "Reading", In: Leonard Woolf (ed.), 1950: The Captain's Death Bed and Other Essays, , London: Hogarth Press, p. 157. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Characteristics of river floods and flooding: a global overview, 1985,2003,,IRRIGATION AND DRAINAGE, Issue S1 2006Klaas-Jan Douben inondation; victims; dommages; stratégies de protection contre les inundations Abstract Since ancient times people have settled in flood-prone areas due to favourable geographic conditions which facilitate economic growth, such as accessibility (transportation) and food production (fertile land). This fact forces societies all over the world to protect valuable assets against flooding. Nevertheless flooding is still the most damaging of all natural disasters. One-third of the annual natural disasters and economic losses and more than half of all victims are flood related. Flood mitigation policies and measures have been implemented, enabling societies to increase their resilience to flood hazards. With increasing population densities, often associated with improved living standards and consequently higher values of property and infrastructure, flood defence receives more importance and the consequences of flooding become less acceptable. Trends in flood frequencies and flooding damage seem to be increasing, primarily due to a growing vulnerability arising from societal changes such as interference by occupation, developments, investments and land-use changes in flood-prone areas. The Asian continent was particularly affected by floods and flooding between 1985 and 2003. It recorded nearly half of all flooding events; together with Europe and North America it was confronted with the majority of flooding damage and it incurred nearly three-quarters of all casualties. Copyright © 2006 John Wiley & Sons, Ltd. Depuis toujours les populations se sont installées dans les zones à risque d'inondation du fait de conditions géographiques favorables à la croissance économique, telles que l'accessibilité (transport) et la production de nourriture (terre fertile). Ceci oblige les sociétés partout dans le monde à protéger les biens contre les inondations. Mais celles-ci sont toujours les plus préjudiciables de tous les désastres naturels. Chaque année, un tiers des désastres naturels et des dommages économiques ainsi que plus de la moitié des victimes sont liés aux inondations. Des politiques et des actions de protection contre les inondations ont été mises en oeuvre, permettant aux sociétés d'augmenter leur résistivité aux risques d'inondation. Avec l'augmentation des densités de population, souvent liée à la progression des niveaux de vie et donc à la valeur plus élevée des habitations et des infrastructures, la protection contre les inondations devient plus importante et leurs conséquences moins acceptables. La fréquence des inondations et de leurs dommages semble en augmentation, principalement en raison d'une vulnérabilité croissante résultant de changements sociaux tels que les interférences des activités, aménagements, investissements et occupation de l'espace dans les zones à risque. Le continent asiatique a été particulièrement affecté entre 1985 et 2003. Il a enregistré presque la moitié de tous les événements d'inondation, a dû faire face à la majorité des dommages avec l'Europe et l'Amérique du Nord et a compté presque trois quarts de toutes les victimes. Copyright © 2006 John Wiley & Sons, Ltd. [source] Medium, Explant and Genotype Factors Influencing Shoot Regeneration in Oilseed Brassica spp.JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2003G. X. Tang Abstract The effects of culture media, explants and genotypes on shoot regeneration in oilseed Brassica species were examined in this study. The maximum shoot regeneration frequency was obtained in Murashige and Skoog medium supplemented with 3 mg l,1 6-benzylaminopurine and 0.15 mg l,1 1-naphthaleneacetic acid. The addition of 2.5 mg l,1 AgNO3 was very beneficial to shoot regeneration in B. napus and Ag2S2O3 (10 mg l,1) was even superior to AgNO3 (2.5 mg l,1). Explant age, explant type and carbon source also significantly affected shoot regeneration. Four-day-old seedlings of cotyledonary explants showed the maximum shoot regeneration frequency and number of shoots per explant. Of the four explants , peduncles, hypocotyls, cotyledons and leaf petioles , cotyledons produced the highest shoot regeneration frequency (56.67 %). Four carbon sources , glucose, maltose, starch and sucrose , were compared for their respective effects on shoot regeneration from cotyledonary explants. Sucrose appeared to be the best carbon source for shoot regeneration with the highest shoot regeneration frequency (76.00 %). Considerable variation in shoot regeneration from cotyledonary explants was observed both between and within Brassica species. The shoot regeneration frequency ranged from 10.00 % for cv. R5 (B. rapa) to 83.61 % for cv. N1 (B. napus). Two B. napus, one B. carinata and one B. juncea cultivars exhibited shoot regeneration frequency higher than 70 %. In terms of the number of shoots produced per explant, B. rapa showed the highest variation, ranging from 5.64 for cv. R3 to 1.33 for cv. R5. Normal plantlets were regenerated from all induced shoots and developed normally. The regenerated plants were fertile and identical with the source plants. [source] Potential for controlling codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) in Argentina using the sterile insect technique and egg parasitoidsJOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2010E. Botto Abstract Codling moth is the main pest affecting apples and pears worldwide. Most pest control strategies used against this insect have relied on the use of broad-spectrum insecticides which have led to non-desirable effects like pesticide resistance, residues in the environment, human health concerns and the reduction of access to international markets. Therefore, alternative pest control strategies that would result in sustainable fruit production systems while taking care of the environment are strongly promoted. The use of the sterile insect technique has proven to be a valuable pest control tactic within area-wide integrated pest management strategies, and its synergistic effect for Lepidoptera pests when combined with other biological control tactics such as parasitoids has been documented. The purposes of this research were to evaluate the response of an Argentinean codling moth strain to a sub-sterilizing radiation dose of 100 Gy and to assess the acceptability and suitability of sterile codling moth eggs by the egg parasitoids, Trichogramma cacoeciae (Marchal) and Trichogramma nerudai (Pintureau and Gerding). Irradiated female moths survived better than irradiated male moths and non-irradiated male and female moths. Also, the fecundity of irradiated female moths was reduced by more than 30% as compared to non-irradiated ones whereas their fertility was close to zero. The F1 generation was male biased with a lower fertility (inherited sterility) than the parental generation. Trichogramma cacoeciae and T. nerudai parasitized both fertile and sterile eggs. However, there was a significant reduction in acceptability for sterile eggs. Trichogramma nerudai parasitized more eggs than T. cacoeciae, but egg acceptability for this species was proportionally lower than for T. cacoeciae especially on eggs oviposited by irradiated females. Development to adult of both parasitoids species was not substantially affected by the origin of the eggs and the wasps had acceptable levels of adult emergence, survival and fecundity. These results provided useful information on the potential for controlling the codling moth using egg parasitoids and the sterile insect technique in Argentina. [source] Tissue histopathology, clinical chemistry and behaviour of adult comt -gene-disrupted miceJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2003Kristiina Haasio Abstract Catechol- O -methyltransferase (COMT) enzyme is a widely distributed enzyme that catalyses O -methylation of catecholamines and other compounds having a catechol structure. Because there has been some concern about the consequences of a low COMT activity in the development of oestrogen-dependent cancers and because one of the COMT inhibitors, tolcapone, has caused serious liver injuries in Parkinsonian patients, the histopathology and clinical chemistry of Comt -gene-disrupted mice were studied at the age of 12 months. Owing to the high COMT activities in liver and kidney and the role of COMT in the metabolism of catechol oestrogens, special emphasis was given to the histology of the liver, kidney and oestrogen-dependent organs such as mammary glands and uterus. The mice of both heterozygous and homozygous genotypes appear to be physically healthy and fertile. Diurnal motility rhythm and behaviour in measuring anxiety and depression were equal in all genotypes. At the age of 12 months, the body weight of homozygous mice was 7,9% lower than that of the other groups. This was re,ected in histology as a diminished incidence of vacuolation of liver cells (fatty change). Macroscopic pathology and histopathology revealed no abnormal ,ndings in any COMT genotype. The values of some clinical chemistry parameters, such as alkaline phosphatase, alanine aminotransferase, urea, glucose, calcium and proteins, were at a higher level in homozygous animals compared with the wild-type mice. However, all the values remained within the normal physiological range, and the differences in enzyme levels between genotypes were not re,ected as histopathological ,ndings in the relevant organs. No changes in haematological parameters or plasma catecholamine concentrations were noted but plasma 3,4-dihydroxyphenylethylene glycol levels were high in COMT null mice. The results suggest that the full or 50% lack of Comt gene as such is not associated with any toxic consequences. Copyright © 2003 John Wiley & Sons, Ltd. [source] Nestling sex ratio of golden-winged warblers Vermivora chrysoptera in an introgressed populationJOURNAL OF AVIAN BIOLOGY, Issue 6 2008Kate J. Neville Sex ratio biases in avian species remain controversial, although several studies have documented apparent facultative adjustment of offspring sex ratios. While hybridizing pied and collared flycatchers have exhibited sex ratio skews that may be a response to sex-based costs associated with hybridization, this appears not to be true of a hybridized population of blue-winged Vermivora pinus and golden-winged V. chrysoptera warblers. We examined the primary sex ratio of nestlings in a population of hybrid and introgressed golden-winged warblers. The sex ratio of 298 nestlings from 81 nests in the population was approximately 50:50. We conducted paternity assignments and analyzed groups of nestlings with shared genetic parents ("genetic broods") and found no difference from the expected binomial distribution, and no statistically significant relationship between parental species phenotype and nestling sex ratio. We saw no evidence of preferential production of male or female nestlings, and female hybrids were found to mate and breed in the population. This suggests that heterogametic (female) hybrids are both viable and fertile, and thus that Haldane's Rule does not apply to this system. While populations of hybridizing golden-winged warblers should be monitored for evidence of costs of heterospecific pairings, it is unlikely that adjustment of sex ratios would be the form of compensation for sub-optimal mating conditions. Our results provide support for the emerging hypothesis that hybrids suffer no disadvantage relative to golden-winged and blue-winged warblers. [source] Disruption of FRNK expression by gene targeting of the intronic promoter within the focal adhesion kinase geneJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2007Haruko Hayasaka Abstract FRNK, a non-catalytic variant of focal adhesion kinase (FAK), is expressed in major blood vessels throughout mouse development and is postulated to play a role in regulating cell adhesion and signaling in vascular smooth muscle cells (VSMCs). The FRNK transcriptional start site lies within an intron of the FAK gene, suggesting that the FRNK gene is a "gene within a gene". Here, we identified a 1 kb intronic sequence of the FAK gene that is necessary for endogenous FRNK expression. Deletion of this sequence in gene-targeted mice abolished FRNK expression, showing the direct involvement of the FAK intron in the regulation of FRNK expression. The level of FAK expression was normal in the FRNK-deficient mice, indicating that FAK and FRNK are transcriptionally regulated by distinct promoters. The FRNK-deficient mice were viable, fertile, and displayed no obvious histological abnormalities in any of the major blood vessels. Western blot analysis showed that FRNK,deficient and wild-type (WT) cells had comparable levels of steady-state and adhesion-dependent FAK autophosphorylation. Despite the fact that ectopic expression of FRNK suppresses focal adhesion formation in cultured cells, these results suggest that endogenous FRNK is not essential for development or the formation of the mouse vasculature. J. Cell. Biochem. 102: 947,954, 2007. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||