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Possible Importance (possible + importance)
Selected AbstractsIncubation Behaviour in Northern Lapwings: Nocturnal Nest Attentiveness and Possible Importance of Individual Breeding QualityETHOLOGY, Issue 3 2004Terje Lislevand Previous studies of sex roles in the polygynous Northern Lapwing Vanellus vanellus have shown that males incubate less than females, perhaps suggesting that sexual selection is important in shaping the parental behaviour of this species. The purpose of this study was to (1) examine for the first time the possibility that males compensate for low diurnal nest attentiveness by increasing their nocturnal assistance and (2) evaluate the hypotheses that sexual selection and individual breeding quality determines incubation behaviour in lapwings. Males were never found incubating at night in 19 nests, although median diurnal male attentiveness was 15.3% in 16 of the same pairs. Nor were there any differences among monogamous and polygynous males in the time spent in four categories of behaviour (incubation, guarding, maintenance and mating activities). The time males spent in mating and incubation behaviours was weakly negatively correlated, and the time spent incubating varied considerably among males (0,74%). Further, female body condition was positively related with male nest attentiveness and there was a negative relationship between nest attentiveness and date of arrival to the study area in monogamous, but not in polygynous, males. We argue that sexual selection could not alone explain all sides of Northern Lapwing incubation, and suggest that individual differences in breeding quality may also be important. [source] Hydrogen peroxide-induced oxidative stress responses in Desulfovibrio vulgaris HildenboroughENVIRONMENTAL MICROBIOLOGY, Issue 10 2010Aifen Zhou Summary To understand how sulphate-reducing bacteria respond to oxidative stresses, the responses of Desulfovibrio vulgaris Hildenborough to H2O2 -induced stresses were investigated with transcriptomic, proteomic and genetic approaches. H2O2 and induced chemical species (e.g. polysulfide, ROS) and redox potential shift increased the expressions of the genes involved in detoxification, thioredoxin-dependent reduction system, protein and DNA repair, and decreased those involved in sulfate reduction, lactate oxidation and protein synthesis. A gene coexpression network analysis revealed complicated network interactions among differentially expressed genes, and suggested possible importance of several hypothetical genes in H2O2 stress. Also, most of the genes in PerR and Fur regulons were highly induced, and the abundance of a Fur regulon protein increased. Mutant analysis suggested that PerR and Fur are functionally overlapped in response to stresses induced by H2O2 and reaction products, and the upregulation of thioredoxin-dependent reduction genes was independent of PerR or Fur. It appears that induction of those stress response genes could contribute to the increased resistance of deletion mutants to H2O2 -induced stresses. In addition, a conceptual cellular model of D. vulgaris responses to H2O2 stress was constructed to illustrate that this bacterium may employ a complicated molecular mechanism to defend against the H2O2 -induced stresses. [source] A CENTENNIAL CELEBRATION FOR QUANTITATIVE GENETICSEVOLUTION, Issue 5 2007Derek A. Roff Quantitative genetics is at or is fast approaching its centennial. In this perspective I consider five current issues pertinent to the application of quantitative genetics to evolutionary theory. First, I discuss the utility of a quantitative genetic perspective in describing genetic variation at two very different levels of resolution, (1) in natural, free-ranging populations and (2) to describe variation at the level of DNA transcription. Whereas quantitative genetics can serve as a very useful descriptor of genetic variation, its greater usefulness is in predicting evolutionary change, particularly when used in the first instance (wild populations). Second, I review the contributions of Quantitative trait loci (QLT) analysis in determining the number of loci and distribution of their genetic effects, the possible importance of identifying specific genes, and the ability of the multivariate breeder's equation to predict the results of bivariate selection experiments. QLT analyses appear to indicate that genetic effects are skewed, that at least 20 loci are generally involved, with an unknown number of alleles, and that a few loci have major effects. However, epistatic effects are common, which means that such loci might not have population-wide major effects: this question waits upon (QTL) analyses conducted on more than a few inbred lines. Third, I examine the importance of research into the action of specific genes on traits. Although great progress has been made in identifying specific genes contributing to trait variation, the high level of gene interactions underlying quantitative traits makes it unlikely that in the near future we will have mechanistic models for such traits, or that these would have greater predictive power than quantitative genetic models. In the fourth section I present evidence that the results of bivariate selection experiments when selection is antagonistic to the genetic covariance are frequently not well predicted by the multivariate breeder's equation. Bivariate experiments that combine both selection and functional analyses are urgently needed. Finally, I discuss the importance of gaining more insight, both theoretical and empirical, on the evolution of the G and P matrices. [source] Secretion of proteases in serglycin transfected Madin,Darby canine kidney cellsFEBS JOURNAL, Issue 3 2006Lillian Zernichow Madin,Darby canine kidney (MDCK) cells, which do not normally express the proteoglycan (PG) serglycin, were stably transfected with cDNA for human serglycin fused to a polyhistidine tag (His-tag). Clones with different levels of serglycin mRNA expression were generated. One clone with lower and one with higher serglycin mRNA expression were selected for this study. 35S-labelled serglycin in cell fractions and conditioned media was isolated using HisTrap affinity chromatography. Serglycin could also be detected in conditioned media using western blotting. To investigate the possible importance of serglycin linked to protease secretion, enzyme activities using chromogenic substrates and zymography were measured in cell fractions and serum-free conditioned media of the different clones. Cells were cultured in both the absence and presence of phorbol 12-myristate 13-acetate (PMA). In general, enzyme secretion was strongly enhanced by treatment with PMA. Our analyses revealed that the clone with the highest serglycin mRNA expression, level of HisTrap isolated 35S-labelled serglycin, and amount of serglycin core protein as detected by western blotting, also showed the highest secretion of proteases. Transfection of serglycin into MDCK cells clearly leads to changes in secretion levels of secreted endogenous proteases, and could provide further insight into the biosynthesis and secretion of serglycin and potential partner molecules. [source] The importance of low atmospheric CO2 and fire in promoting the spread of grasslands and savannasGLOBAL CHANGE BIOLOGY, Issue 7 2003W. J. BOND Abstract The distribution and abundance of trees can be strongly affected by disturbance such as fire. In mixed tree/grass ecosystems, recurrent grass-fuelled fires can strongly suppress tree saplings and therefore control tree dominance. We propose that changes in atmospheric [CO2] could influence tree cover in such metastable ecosystems by altering their postburn recovery rates relative to flammable herbaceous growth forms such as grasses. Slow sapling recovery rates at low [CO2] would favour the spread of grasses and a reduction of tree cover. To test the possible importance of [CO2]/fire interactions, we first used a Dynamic Global Vegetation Model (DGVM) to simulate biomass in grassy ecosystems in South Africa with and without fire. The results indicate that fire has a major effect under higher rainfall conditions suggesting an important role for fire/[CO2] interactions. We then used a demographic model of the effects of fire on mesic savanna trees to test the importance of grass/tree differences in postburn recovery rates. We adjusted grass and tree growth in the model according to the DGVM output of net primary production at different [CO2] relative to current conditions. The simulations predicted elimination of trees at [CO2] typical of the last glacial period (180 ppm) because tree growth rate is too slow (15 years) to grow to a fire-proof size of ca. 3 m. Simulated grass growth would produce an adequate fuel load for a burn in only 2 years. Simulations of preindustrial [CO2] (270 ppm) predict occurrence of trees but at low densities. The greatest increase in trees occurs from preindustrial to current [CO2] (360 ppm). The simulations are consistent with palaeo-records which indicate that trees disappeared from sites that are currently savannas in South Africa in the last glacial. Savanna trees reappeared in the Holocene. There has also been a large increase in trees over the last 50,100 years. We suggest that slow tree recovery after fire, rather than differential photosynthetic efficiencies in C3 and C4 plants, might have been the significant factor in the Late Tertiary spread of flammable grasslands under low [CO2] because open, high light environments would have been a prerequisite for the spread of C4 grasses. Our simulations suggest further that low [CO2] could have been a significant factor in the reduction of trees during glacial times, because of their slower regrowth after disturbance, with fire favouring the spread of grasses. [source] The Role of c-Jun N-Terminal Kinase (JNK) in Parkinson's DiseaseIUBMB LIFE, Issue 4-5 2003Jun Peng Abstract Given the critical role that the c-Jun N-terminal kinase (JNK) pathway plays in regulating many of the cellular processes which are affected in Parkinson's disease (PD), the possible importance of JNK in disease pathogenesis is being increasingly recognized. Here we review recent findings implicating the JNK signaling pathway in animal models of Parkinson's disease and discuss the relationship between this pathway and the prominent pathological processes observed in the disease state. We suggest that regulation of the JNK signaling pathway may be a central facet in potential treatments for the disease. IUBMB Life, 55: 267-271, 2003 [source] New Caledonian biogeography: a reply to MurienneJOURNAL OF BIOGEOGRAPHY, Issue 8 2010Michael Heads Abstract This note replies to criticisms raised by Murienne (Journal of Biogeography, 2010, doi:10.1111/j.1365-2699.2010.02321.x). Herein it is argued that assuming distributions in New Caledonia are caused by current environmental factors overlooks the possible importance of regional tectonic history for the biogeography. [source] Serum and glucocorticoid-regulated protein kinases: Variations on a themeJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2006Maude Tessier Abstract The phosphatidylinositol 3, kinase (PI3K)-signaling pathway plays a critical role in a variety of cellular responses such as modulation of cell survival, glucose homeostasis, cell division, and cell growth. PI3K generates important lipid second messengers,phosphatidylinositides that are phosphorylated at the 3, position of their inositol ring head-group. These membrane restricted lipids act by binding with high affinity to specific protein domains such as the pleckstrin homology (PH) domain. Effectors of PI3K include molecules that harbor such domains such as phosphoinositide-dependent kinase (PDK1) and protein kinase B (PKB), also termed Akt. The mammalian genome encodes three different PKB genes (,, ,, and ,; Akt1, 2, and 3, respectively) and each is an attractive target for therapeutic intervention in diseases such as glioblastoma and breast cancer. A second family of three protein kinases, termed serum and glucocorticoid-regulated protein kinases (SGKs), is structurally related to the PKB family including regulation by PI3K but lack a PH domain. However, in addition to PH domains, a second class of 3, phosphorylated inositol phospholipid-binding domains exists that is termed Phox homology (PX) domain: this domain is found in one of the SGKs (SGK3). Here, we summarize knowledge of the three SGK isoforms and compare and contrast them to PKB with respect to their possible importance in cellular regulation and potential as therapeutic targets. J. Cell. Biochem. © 2006 Wiley-Liss, Inc. [source] Dynamics of host plant use and species diversity in Polygonia butterflies (Nymphalidae)JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2006E. WEINGARTNER Abstract The ability of insects to utilize different host plants has been suggested to be a dynamic and transient phase. During or after this phase, species can shift to novel host plants or respecialize on ancestral ones. Expanding the range of host plants might also be a factor leading to higher levels of net speciation rates. In this paper, we have studied the possible importance of host plant range for diversification in the genus Polygonia (Nymphalidae, Nymphalini). We have compared species richness between sistergroups in order to find out if there are any differences in number of species between clades including species that utilize only the ancestral host plants (,urticalean rosids') and their sisterclades with a broader (or in some cases potentially broader) host plant repertoire. Four comparisons could be made, and although these are not all phylogenetically or statistically independent, all showed clades including butterfly species using other or additional host plants than the urticalean rosids to be more species-rich than their sisterclade restricted to the ancestral host plants. These results are consistent with the theory that expansions in host plant range are involved in the process of diversification in butterflies and other phytophagous insects, in line with the general theory that plasticity may drive speciation. [source] Central corneal thickness in European (white) individuals, especially children and the elderly, and assessment of its possible importance in clinical measures of intra-ocular pressureOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2002Michael J. Doughty Purpose:,To ascertain the impact of central corneal thickness (CCT, as assessed by pachometry) and central corneal curvature (as assessed by keratometry) on clinical measures of intra-ocular pressure (IOP, as assessed by tonometry), especially in the young and elderly. Methods:,Pachometry, keratometry and tonometry were carried out on three groups, namely children aged 5,15 years, adults aged 32,60 years, and elderly individuals aged between 61 and 82 years. For children, ultrasound pachometry was combined with non-contact tonometry (NCT), specular microscopy was used with Perkins tonometry in the adults, and ultrasound pachometry was used with Perkins tonometry for the elderly. Central corneal curvature was assessed by keratometry. Results:,The average CCT in children was 0.529 ± 0.034 mm (n=104, ±S.D.), averaged 0.533 ± 0.033 in adults (n=75) and 0.527 ± 0.034 mm (n=91) in the elderly. Tonometry values averaged 16.7 ± 2.9 mm in children, 13.0 ± 3.5 mmHg in adults and 13.6 ± 2.5 mm in the elderly group. Central corneal thickness values were not predictably different in relation to central corneal curvature values. Regression analyses indicated that the tonometry values were higher in both children and the elderly who had thicker corneas (and vice versa) (p , 0.003), with the measures increasing by 1.3 ± 0.4 and 2.6 ± 0.4 mmHg for a 10% difference in CCT in children and the elderly, respectively. For adults, no statistically significant difference in tonometry values could be demonstrated with respect to CCT (<1 mmHg for a 10% difference in CCT), and for no group were the CCT or tonometry values predictably different in relation to central corneal curvature values. Conclusions:,The results of these studies, albeit relatively small scale, indicate that in young or elderly individuals with essentially normal IOP and CCT measures, the tonometry values show only small differences with respect to CCT. The slope in the observed relationship was not that different from an average of 1.5 mmHg for a 10% different in CCT, as obtained from a literature analysis over a 30-year period. The magnitude of the effect does not provide evidence that pachometry needs to be routinely performed in glaucoma screening protocols based on tonometry. Notwithstanding, the finding of higher than expected tonometry values should be further investigated, by pachometry, especially in very young children and in the elderly. [source] In situ analysis of enzymes involved in sucrose to hexose-phosphate conversion during stolon-to-tuber transition of potatoPHYSIOLOGIA PLANTARUM, Issue 2 2002Niek J.G. Appeldoorn An in situ study of enzymes involved in sucrose to hexose-phosphate conversion during in vitro stolon-to-tuber transition of potato (Solanum tuberosum L. cv. Bintje) was employed to follow developmental changes in spatial patterns. In situ activity of the respective enzymes was visualized by specific activity-staining techniques and they revealed distinct spatially and developmentally regulated patterns. Two of the enzymes studied were also subject to in situ investigations at the transcriptional level. During the stages of stolon formation high hexokinase (EC 2.7.1.1) and acid (cell wall-bound) invertase (EC 3.2.1.26) activities were restricted to the mitotically active (sub)apical region, suggesting a possible importance of these enzymes for cell division. At the onset of tuberization sucrose synthase (EC 2.4.1.13) and fructokinase (EC 2.7.1.4) were strongly induced (visualized at transcriptional and translational level) and the acid invertase activities disappeared from the swelling subapical region as expected. The high degree of similarity in the spatial pattern and the temporal induction of sucrose synthase and fructokinase suggests a tightly co-ordinated coarse (up)regulation, which may be subject to a sugar-modulated mechanism(s) by which genes involved in the metabolic sucrose-starch converting potential are co-ordinately regulated during tuber growth. The overall activity of uridine-5-diphosphoglucose pyrophosphorylase (EC 2.7.7.9) was present in all tissues during stolon and tuber development, implying that its coarse control is not subject to (in)direct developmental regulation. [source] Social learning and mother's behavior in manipulative tasks in infant marmosetsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2009Vera Dell'Mour Abstract High levels of social tolerance are considered to promote social learning, as they allow direct observation of a manipulating conspecific and facilitate scrounging. Owing to tolerance toward infants, infancy is thought to be especially suited for learning socially transmitted behaviors. Despite this, few studies have investigated social learning of infants, particularly in manipulative tasks where observation might be most helpful. Here, we investigated (1) the influence of social learning on task acquisition in infant marmosets, and (2) whether the mother augments her behavior in a way that may enhance social learning by her infants. We tested infant and juvenile marmosets in four different complex foraging-related tasks, featuring large living insects (two tasks) or artificially embedded prey (two tasks). Each individual observed the mother solving two of the tasks and served as a control in the other two tasks. Observers manipulated more and succeeded sooner than control animals, suggesting that observing the mother promoted learning either directly or by decreasing neophobia. Moreover, the data suggest that learning in 11,15 week-old infants might be promoted actively by the mother. She solved the tasks, consumed less food, and consumed it later than when foraging with older offspring or alone. Furthermore, the results indicate the possible importance of the third and fourth month of infancy as the crucial ontogenetic period for social learning in marmosets, corroborating recent observations of free-living common marmosets. Am. J. Primatol. 71:503,509, 2009. © 2009 Wiley-Liss, Inc. [source] Genetics of basal cell carcinomaAUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 2 2010Sally E De Zwaan ABSTRACT Basal cell carcinoma is the most common human malignancy in populations of European origin, and Australia has the highest incidence of basal cell carcinoma in the world. Great advances in the understanding of the genetics of this cancer have occurred in recent years. Mutations of the patched 1 gene (PTCH1) lead to basal cell carcinoma predisposition in Gorlin syndrome. PTCH1 is part of the hedgehog signalling pathway, and derangements within this pathway are now known to be important in the carcinogenesis of many different cancers including sporadic basal cell carcinoma. The molecular biology of the hedgehog pathway is discussed, and mouse models of basal cell carcinoma based on this pathway are explored. New developments in non-surgical treatment of basal cell carcinoma are based on this knowledge. Other genes of importance to basal cell carcinoma development include the tumour suppressor gene P53 and the melanocortin-1 receptor gene. In addition, we discuss molecules of possible importance such as the glutathione-S-transferases, DNA repair genes, cyclin-dependent kinase inhibitor 2A, Brahma and connexins. Evidence of familial aggregation of this cancer is explored and supports the possibility of genetic predisposition to this common malignancy. [source] Phosphodiesterase-linked inhibition of nonmicturition activity in the isolated bladderBJU INTERNATIONAL, Issue 9 2004J.I. Gillespie Over the past few months Gillespie has published several papers in the BJU International investigating the overactive bladder and BOO, using novel models and theories. This next paper continues these concepts and shows that the mechanisms influencing the frequency of agonist-induced phasic activity in the isolated bladder model is slowed by cAMP. These findings will have important implications in future pharmacological strategies in the overactive bladder. OBJECTIVE To explore the influence of intracellular cAMP on phasic activity in the isolated bladder (phasic rises in intravesical pressure associated with waves of contraction and local stretches that can be activated by muscarinic or nicotinic agonists), as it has been argued that this activity underlies nonmicturition contractions, and that it contributes to the generation and modulation of afferent nerve activity. MATERIALS AND METHODS Isolated whole bladders from female guinea pigs (270,300 g) were cannulated via the urethra and suspended in a chamber containing oxygenated Tyrode solution at 33,35 °C. Bladder pressure was recorded and pharmacological agents added to the solution bathing the abluminal surface of the bladder. RESULTS Forskolin (1,3 µmol/L), an activator of adenyl cyclase, reduced the frequency and amplitude of the phasic activity induced by the muscarinic agonist arecaidine (300 nmol/L). There were similar changes in frequency and amplitude in bladders exposed to the nonspecific phosphodiesterase (PDE) inhibitor iso-butyl-methyl-xanthene (IBMX). The actions of specific PDE inhibitors were explored to assess which isoenzymes might be responsible for regulating phasic activity. ENHA (PDE-2), zaprinast (PDE-5, -6, -8, -9 and -11) and siguazodan (PDE-3) had no effect. Zardavarine (PDE-3, -4) and Ro 20-1724 (PDE-4) reduced both the frequency and amplitude of the phasic activity. Nerve-mediated rises in intravesical pressure were also inhibited by Ro 20-1724, and the inhibition was more pronounced at 6.5 Hz than at 30 Hz stimulation. Ro 20-1724 inhibited nerve-mediated fluctuations induced by prolonged (200 s) stimulation at 6.5 Hz. CONCLUSION The mechanisms influencing the frequency of agonist-induced phasic activity in the isolated bladder are slowed by cAMP. Degradation of intracellular cAMP in the cells responsible for phasic activity appears to involve primarily PDE-4. The importance of these observations in relation to the overall physiological regulation of the bladder are discussed, and the possible importance of these findings in the development of pharmacological strategies to modulated bladder activity reviewed. [source] | |||||||||||||