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Tail Length (tail + length)
Selected AbstractsAdaptive Offspring Sex Ratio Depends on Male Tail Length in the GuppyETHOLOGY, Issue 11 2006Kenji Karino A biased sex ratio in a brood is considered to be an adaptive strategy under certain circumstances. For example, if the expected reproductive success of one sex is greater than that of the other, parents should produce more offspring of the former sex than the latter. A previous study has documented that in the guppy, Poecilia reticulata, the female offspring of males possessing proportionally longer tails exhibit smaller body sizes and show decreased reproductive outputs than those of males having shorter tails. On the other hand, the total lengths of the male offspring of the long-tailed males are larger because of their longer tails; consequently, they exhibit greater sexual attractiveness to females. Therefore, it has been hypothesized that this asymmetry in the expected reproductive success between the male and female offspring of long-tailed males may result in a biased sex ratio that is dependent on the tail lengths of their fathers. This hypothesis was tested in the present study. The results showed that the females that mated with long-tailed males produced more male offspring than those that mated with short-tailed males. Logistic regression analysis showed that the ratio of tail length to the standard length of the fathers is a determinant factor of the sex of their offspring. These results suggest that the manipulation of the offspring sex ratios by parents enhances the overall fitness of the offspring. [source] Oral malodorous compound causes apoptosis and genomic DNA damage in human gingival fibroblastsJOURNAL OF PERIODONTAL RESEARCH, Issue 4 2008K. Yaegaki Background and Objective:, Volatile sulfur compounds are the main cause of halitosis. Hydrogen sulfide is one of these volatile sulfur compounds and the principal malodorous compound in physiological halitosis. Periodontally pathogenic activities of hydrogen sulfide have been previously reported. Hydrogen sulfide induces apoptotic cell death in aorta smooth muscle cells and in other tissues. Apoptosis plays an important role in the onset and progress of periodontitis. The objective of this study was to determine whether hydrogen sulfide causes apoptosis in human gingival fibroblasts. Material and methods:, Necrotic cells were detected using a lactate dehydrogenase assay. Apoptosis was ascertained using a histone-complexed DNA fragment assay and flow cytometry. The level of caspase 3, a key enzyme in apoptotic signaling, was also measured, and the effects of hydrogen sulfide on reactive oxygen species and superoxide dismutase were assessed. DNA damage caused by hydrogen sulfide was examined by means of single-cell gel electrophoresis. Results:, After 72 h of incubation with 100 ng/mL of hydrogen sulfide, necrosis was found in less than 10% of human gingival fibroblasts, whereas apoptosis was significantly increased (p < 0.05). Superoxide dismutase activity was strongly inhibited, and reactive oxygen species production was enhanced, after 48 and 72 h of incubation. Caspase 3 activity was also increased after 72 h of incubation (p < 0.01). Tail length, percentage of DNA in tail, and tail moment, measured by single-cell gel electrophoresis, were also intensified after 72 h of incubation (p < 0.001). Conclusion:, Hydrogen sulfide caused apoptosis and DNA damage in human gingival fibroblasts. An increased level of reactive oxygen species stimulated by hydrogen sulfide may induce apoptosis and DNA strand breaks. [source] Growth and development of giant panda (Ailuropoda melanoleuca) cubs at Beijing ZooJOURNAL OF ZOOLOGY, Issue 2 2001Jianjun Peng Abstract We studied the postnatal body weight gain and development of 11 male and nine female giant panda Ailuropoda melanoleuca cubs born at Beijing Zoo from 1985 to 1998. Growth rates of the cubs appeared to be sexually dimorphic from the fourth month after birth; the male grew slightly faster than the female cubs. Growth rates between artificially fed and naturally fed cubs were significantly different from the fourth month after birth. The growth rate of the artificially fed cubs was slightly higher than that of the cubs fed by their mothers, indicating that the substitute milk satisfied the nutrient needs of the cubs. The body length of the cubs increased rapidly after birth; 8-month-old cubs were three times longer than newborn cubs. Chest circumferences of 8-month-old cubs also increased to twice that of newborn cubs. Tail length relative to body length was reduced from 14.9% at birth to about 8.6% in 8-month-old cubs. Cubs started to grow teeth when they were 3 months old. By the age of 1 year, the cubs had fully grown deciduous teeth. The teeth formula of one 1-year-old cub was 2·1·3·0/2·1·3·0=24. We recorded the changes in fur colour, development of the sense organs and limbs of the giant panda cubs. Finally, we compared the body weight and life-history parameters of giant pandas with those of bears and raccoons and discussed the management regime for the care of captive-born giant panda cubs. [source] Experimental evidence for female choice and energetic costs of male tail elongation in red-collared widowbirdsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2005SARAH R. PRYKE The black nuptial plumage of the highly polygynous male red-collared widowbird (Euplectes ardens) comprises a red carotenoid-based collar patch and a long graduated tail (c. 22 cm). Tail length was the strongest predictor of male mating success in a previous selection analysis, motivating this experimental test of the relative importance of tail plumes in male contest competition and female choice. Males were assigned to either a short (12.5 cm) or control (20 cm) tail manipulation prior to territory establishment. Male contest competition was unaffected by the tail treatments as the shortened- and control-tailed males were equally successful in acquiring territories of similar size and quality. In contrast, however, although the longer-tailed control males spent less time in flight and courtship displays, they attracted significantly more prospecting and nearly three times as many nesting females to their territories compared to the short-tailed males. In further support of tail length as the primary mate choice cue, none of the other measured and potential female cues (e.g. body size, collar colorimetrics, territorial behaviours or territory quality) influenced male reproductive success. In addition to potentially increasing detectability (,signal efficacy'), the long tail is also a likely indicator of male quality (,signal content'). Despite the higher activities of short-tailed males, control-tailed males showed a steeper decline in condition (relative body mass) during the breeding season. Furthermore, both short- and control-tailed residents lost more condition than did the short- and control-treated floaters (males not establishing territories), suggesting an interaction between tail length and the costs of territory acquisition, defence and courtship displays. These results confirm the role of mate choice and honest quality advertising as the main selection pressures behind elongated tails in widowbirds. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 35,43. [source] Resilience of arboreal folivores to habitat damage by a severe tropical cycloneAUSTRAL ECOLOGY, Issue 4 2008ROBYN F. WILSON Abstract Severe tropical cyclones greatly modify habitat of arboreal folivores by destroying forest canopy, reducing structure and complexity and defoliating remaining trees. We hypothesized that forest modification following severe Cyclone Larry would stress arboreal folivores of the Family Pseudocheiridae and be reflected in increased home ranges and a decrease in body condition. We conducted 19 pre-cyclone and 24 post-cyclone spotlighting surveys at a site with severe cyclone damage, and 18 post-cyclone surveys at a site with minor damage. We detected a greater number of lemuroid, Hemibelideus lemuroides and green, Pseudochirops archeri, ringtail possums as these possums remained in the severely damaged canopy and forest edge. In contrast, Herbert River ringtail possums, Pseudochirulus herbertensis, were detected in smaller numbers. We radio-tracked eight P. herbertensis before the cyclone, following two of these and nine new animals after the category 4 cyclone. No significant post-cyclone alteration in home range area or span was recorded in data pooled across the two sites or in limited post-cyclone data at the severely disturbed site, but a greater variability in home range was observed after cyclone (pooled across sites: 1.72 ± 0.77 ha; 197 ± 47 m) than before the cyclone (1.35 ± 0.30 ha; 196 ± 23 m). In contrast, pooled pre- and post-cyclone home range areas and spans were larger at the severely-disturbed site (2.08 ± 0.56 ha; 231 ± 32 m) than at the site with minor damage (0.68 ± 0.11 ha; 114 ± 25 m), suggesting resources were more widely spread at the former site. Post-cyclone home ranges were also larger at the severely damaged site (severe: 3.33 ± 1.36 ha, n = 3; minor: 0.52 ± 0.07 ha, n = 4). Condition of P. herbertensis (mass/tail length) did not differ significantly pre- and post-cyclone or between less and severely disturbed sites. These results and observations of breeding after cyclone suggest that possum populations may be resilient to severe cyclone damage under the relatively wet conditions experienced post-Cyclone Larry. [source] Effects of in utero exposure to 2,2,,4,4,,5,5,-hexachlorobiphenyl (PCB 153) on somatic growth and endocrine status in rat offspringCONGENITAL ANOMALIES, Issue 4 2008Kenichi Kobayashi ABSTRACT Exposure to polychlorobiphenyl (PCB) mixtures at an early stage of development has been reported to affect endocrine glands; however, little is known about the precise toxicological properties of individual PCB. The present study was undertaken to determine whether prenatal exposure to 2,2,,4,4,,5,5,-hexachlorobiphenyl (PCB 153), a di- ortho -substituted non-coplanar congener, affects postnatal development in rat offspring. Pregnant Sprague-Dawley rats (Crj: CD (SD) IGS) were given PCB 153 (0, 16, or 64 mg/kg/day) orally from gestational day (GD) 10 through GD 16, and developmental parameters in the male and female offspring were examined. We found no dose-dependent changes in body weight, body length (nose,anus length), tail length, or the weights of kidneys, testes, ovaries and uterus in offspring at 1 or 3 weeks of age. Liver weights were increased in the PCB 153,treated groups, although we observed a significant difference only in males. Anogenital distance was unaffected in the PCB 153,treated groups. We observed a significant dose-dependent decrease in the plasma concentrations of thyroxine and tri-iodothyronine, whereas those of thyroid-stimulating hormone were not significantly changed. In addition, there were no dose-dependent changes in plasma concentrations of growth hormone and insulin-like growth factor-I in any dose group. These findings suggest that prenatal exposure to PCB 153 (GD 10,16, 16,64 mg/kg/day) may alter the thyroid status in rat offspring to some extent without affecting somatic growth or its related hormonal parameters. [source] DNA damage in Pakistani pesticide-manufacturing workers assayed using the Comet assayENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 8 2006Javed A. Bhalli Abstract The production and use of chemical pesticides has increased in recent years. Although the increased use of pesticides may benefit agriculture, they are also the potential source of environmental pollution, and exposure to pesticides can have negative consequences for human health. In the present study, we have assessed DNA damage in blood leukocytes from 29 Pakistani pesticide-factory workers and 35 controls of similar age and smoking history. The workers were exposed to various mixtures of organophosphates, carbamates, and pyrethroids. DNA damage was measured with the single cell gel electrophoresis (SCGE) assay or Comet assay, using the mean comet tail length (,m) as the DNA damage metric. Exposed workers had significantly longer comet tail lengths than the controls (mean ± SD 19.98 ± 2.87 vs. 7.38 ± 1.48, P < 0.001). Of the possible confounding factors, smokers had significantly longer mean comet tail lengths than nonsmokers and exsmokers for both the workers (21.48 ± 2.58 vs.18.37 ± 2.28, P < 0.001) and the controls (8.86 ± 0.56 vs. 6.79 ± 1.31, P < 0.001), while age had a minimal effect on DNA damage (P > 0.05 and P < 0.05 for workers and controls, respectively). The results of this study indicate that occupational exposure to pesticides causes DNA damage. Environ. Mol. Mutagen., 2006. © 2006 Wiley-Liss, Inc. [source] Monitoring of DNA breakage in embryonic stages of the African catfish Clarias gariepinus (Burchell, 1822) after exposure to lead nitrate using alkaline comet assayENVIRONMENTAL TOXICOLOGY, Issue 6 2008Alaa G. M. Osman Abstract Increasing lead contamination in Egyptian ecosystems and high lead concentrations in food items have raised concern for human health and stimulated studies on monitoring ecotoxicological impact of lead-caused genotoxicity. In this work, the alkaline comet assay was modified for monitoring DNA strand breakage in sensitive early life stages of the African catfish Clarias gariepinus. Following exposure to 100, 300, and 500 ,g/L lead nitrate, DNA strand breakage was quantified in embryos at 30, 48, 96, 144, and 168 h post-fertilization (PFS). For quantitative analysis, four commonly used parameters (tail % DNA, %TDNA; head % DNA, %HDNA; tail length, TL; tail moment, TM) were analyzed in 96 nuclei (in triplicates) at each sampling point. The parameter %TDNA revealed highest resolution and lowest variation. A strong correlation between lead concentration, time of exposure, and DNA strand breakage was observed. Here, genotoxicity detected by comet assay preceded the manifested malformations assessed with conventional histology. Qualitative evaluation was carried out using five categories are as follows: undamaged (%TDNA , 10%), low damaged (10% < %TDNA , 25%), median damaged (25 < %TDNA , 50%), highly damaged (50 < %TDNA , 75%), and extremely damaged (%TDNA > 75%) nuclei confirming a dose and time-dependent shift towards increased frequencies of highly and extremely damaged nuclei. A protective capacity provided by a hardened chorion is a an interesting finding in this study as DNA damage in the prehatching stages 30 h-PFS and 48 h-PFS was low in all treatments (qualitative and quantitative analyses). These results clearly show that the comet assay is a sensitive tool for the detection of genotoxicity in vulnerable early life stages of the African catfish and is a method more sensitive than histological parameters for monitoring genotoxic effects. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Adaptive Offspring Sex Ratio Depends on Male Tail Length in the GuppyETHOLOGY, Issue 11 2006Kenji Karino A biased sex ratio in a brood is considered to be an adaptive strategy under certain circumstances. For example, if the expected reproductive success of one sex is greater than that of the other, parents should produce more offspring of the former sex than the latter. A previous study has documented that in the guppy, Poecilia reticulata, the female offspring of males possessing proportionally longer tails exhibit smaller body sizes and show decreased reproductive outputs than those of males having shorter tails. On the other hand, the total lengths of the male offspring of the long-tailed males are larger because of their longer tails; consequently, they exhibit greater sexual attractiveness to females. Therefore, it has been hypothesized that this asymmetry in the expected reproductive success between the male and female offspring of long-tailed males may result in a biased sex ratio that is dependent on the tail lengths of their fathers. This hypothesis was tested in the present study. The results showed that the females that mated with long-tailed males produced more male offspring than those that mated with short-tailed males. Logistic regression analysis showed that the ratio of tail length to the standard length of the fathers is a determinant factor of the sex of their offspring. These results suggest that the manipulation of the offspring sex ratios by parents enhances the overall fitness of the offspring. [source] Xenopus Rbm9 is a novel interactor of XGld2 in the cytoplasmic polyadenylation complexFEBS JOURNAL, Issue 3 2008Catherine Papin During early development, control of the poly(A) tail length by cytoplasmic polyadenylation is critical for the regulation of specific mRNA expression. Gld2, an atypical poly(A) polymerase, is involved in cytoplasmic polyadenylation in Xenopus oocytes. In this study, a new XGld2-interacting protein was identified: Xenopus RNA-binding motif protein 9 (XRbm9). This RNA-binding protein is exclusively expressed in the cytoplasm of Xenopus oocytes and interacts directly with XGld2. It is shown that XRbm9 belongs to the cytoplasmic polyadenylation complex, together with cytoplasmic polyadenylation element-binding protein (CPEB), cleavage and polyadenylation specificity factor (CPSF) and XGld2. In addition, tethered XRbm9 stimulates the translation of a reporter mRNA. The function of XGld2 in stage VI oocytes was also analysed. The injection of XGld2 antibody into oocytes inhibited polyadenylation, showing that endogenous XGld2 is required for cytoplasmic polyadenylation. Unexpectedly, XGld2 and CPEB antibody injections also led to an acceleration of meiotic maturation, suggesting that XGld2 is part of a masking complex with CPEB and is associated with repressed mRNAs in oocytes. [source] Experimental tail shortening in Barn Swallows (Hirundo rustica) affects haematocritFUNCTIONAL ECOLOGY, Issue 5 2005J. J. CUERVO Summary 1Recent studies in Scotland suggest that the outermost tail feathers of Barn Swallows (Hirundo rustica Linnaeus) may be around 10,12 mm longer than the aerodynamic optimum, with sexual selection for long tails accounting for this extra length. 2To test this hypothesis, we shortened the outermost tail feathers in male and female Barn Swallows in southern Spain by cutting 1, 11 or 21 mm from the tips of the feathers, and checked for change in haematocrit 1 month later. Haematocrit levels were high when birds arrived at the breeding grounds due to an intense effort for flight during migration, but these levels decreased during the breeding season. We predicted that this decrease would be more pronounced when tail length was closer to the aerodynamic optimum (tails shortened by 11 mm), and less pronounced as tail length was displaced from that optimum (tails shortened by 1 or 21 mm). 3Contrary to expectations, we found that the smaller the experimental reduction in tail length, the more pronounced the decrease in haematocrit. Barn Swallows with little parental effort and originally long tail feathers experienced a more pronounced decrease in haematocrit than individuals with strong parental effort and originally short tail feathers, respectively, although only in the group of birds with tails shortened by 21 mm. 4These results do not support the hypothesis that outermost tail feathers in Barn Swallows have been elongated because of sexual selection, at least in the population studied, but are consistent with tail length being at an aerodynamic optimum, or very close to it. Differences in tail length among populations might help to understand the disagreement with previous studies. [source] Endogenous DNA damage and testicular germ cell tumorsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2009M. B. Cook Summary Testicular germ cell tumors are comprised of two histologic groups, seminomas and non-seminomas. We postulated that the possible divergent pathogeneses of these histologies may be partially explained by variable levels of net endogenous DNA damage. To test our hypothesis, we conducted a case,case analysis of 51 seminoma and 61 non-seminoma patients using data and specimens from the Familial Testicular Cancer study and the U.S. Radiologic Technologists cohort. A lymphoblastoid cell line was cultured for each patient and the alkaline comet assay was used to determine four parameters: tail DNA, tail length, comet distributed moment (CDM) and Olive tail moment (OTM). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using logistic regression. Values for tail length, tail DNA, CDM and OTM were modelled as categorical variables using the 50th and 75th percentiles of the seminoma group. Tail DNA was significantly associated with non-seminoma compared with seminoma (OR50th percentile = 3.31, 95% CI: 1.00, 10.98; OR75th percentile = 3.71, 95% CI: 1.04, 13.20; p for trend = 0.039). OTM exhibited similar, albeit statistically non-significant, risk estimates (OR50th percentile = 2.27, 95% CI: 0.75, 6.87; OR75th percentile = 2.40, 95% CI: 0.75, 7.71; p for trend = 0.12) whereas tail length and CDM showed no association. In conclusion, the results for tail DNA and OTM indicate that net endogenous levels are higher in patients who develop non-seminoma compared with seminoma. This may partly explain the more aggressive biology and younger age-of-onset of this histologic subgroup compared with the relatively less aggressive, later-onset seminoma. [source] Evaluation of cytogenetic effects of lambda-cyhalothrin on human lymphocytesJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 5 2005Rambabu Naravaneni Abstract The genotoxic and cytotoxic potential of lambda-cyhalothrin (LCT), a synthetic pyrethroid insecticide, was investigated on human lymphocytes cultured in vitro. Utilizing the trypan blue dye exclusion technique assay, the LC50 of LCT was found to be 28 , M. Based on the LC50 value, it is seen that LCT was highly toxic to lymphocyte cultures, among other pyrethroid group of pesticides. Chromosomal aberrations induced by LCT were determined using metaphase plate-spreads of lymphocytes. The chromosomal analysis was recorded using Medi-Image software technology. The analysis revealed that more satellite associations and gaps were found, which were statistically significant (p < 0.05) when compared to controls. Comet assay was used to assess the possibility of LCT to induce the damage in DNA, where the increase in comet tail length relates to the extent of DNA single strand breaks. The results presented here indicate that in vitro assays could be used as indicators of cytotoxicity and genotoxicity of the pesticide. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:304,310, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20095 [source] Selenium Deficiency-Induced Growth Retardation Is Associated with an Impaired Bone Metabolism and OsteopeniaJOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2001Rodrigo Moreno-Reyes Abstract Although the importance of selenium for bone metabolism is unknown, some clinical conditions such as Kashin-Beck osteoarthropathy have been associated with selenium deficiency. Although selenium deficiency induces growth retardation in rats, it has not been established whether this growth inhibition is associated with changes in bone metabolism. We investigated the effect of selenium deficiency on bone metabolism in growing male rats fed a selenium-deficient diet for two generations (Se,). In Se, rats, erythrocyte glutathione peroxidase activity and plasma selenium concentration were strongly reduced compared with pair-fed selenium-adequate rats (Se+). Weight and tail length were reduced by 31% and 13% in the Se, rats, respectively (p < 0.001). The Se, diet was associated with a 68% reduction of pituitary growth hormone (GH; p = 0.01) and a 50% reduction of plasma insulin-like growth factor I (IGF-I; p < 0.001). Plasma calcium was lower and urinary calcium concentration was greater in Se, rats. This group had a 2-fold increase in parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] in plasma. Plasma osteocalcin and urinary deoxypyridoline were reduced by 25% and 57% in the Se, rats (p < 0.001). Selenium deficiency resulted in a 23% and 21% reduction in bone mineral density (BMD) of the femur and tibia (p < 0.001) and this effect persisted after adjustment for weight in a linear regression model. A 43% reduction in trabecular bone volume of the femoral metaphysis (p < 0.001) was found in Se, rats. This experimental study shows that growth retardation induced by selenium deficiency is associated with impaired bone metabolism and osteopenia in second-generation selenium-deficient rats. [source] Life on a limb: ecology of the tree agama (Acanthocercus a. atricollis) in southern AfricaJOURNAL OF ZOOLOGY, Issue 4 2002Leeann T. Reaney Abstract One hundred and sixty-four museum specimens of the tree agama Acanthocercus a. atricollis were measured and dissected to examine sexual size dimorphism, reproduction and diet. Foraging mode and behaviour were also quantified in a wild population to obtain a broader picture of their foraging ecology and to test the hypothesis that tree agamas are ambush foragers. Males and females did not differ significantly in snout,vent length (SVL) or tail length; however, mature males had larger heads than females of the same body size. The smallest female showing sexual maturity was 96 mm SVL and the smallest male was 82 mm SVL. Mean clutch size was 11.3 and was positively correlated with female body size. Reproduction was seasonal and male and female reproductive cycles were synchronous. Testicular volume was greatest during August,September and females contained enlarged follicles during August,December and showed no evidence of multiple clutching. Tree agamas fed on a broad spectrum of arthropods (10 orders), including millipedes, which other lizard taxa have been reported to avoid. Gut contents were dominated numerically by ants (92%), followed by beetles (4%). Volumetrically, orthopterans (26.8%) were most important, followed by beetles (26.3%) and ants (17.9%). Compared to adults, juvenile diet by volume was dominated by ants and consisted of fewer large prey items (e.g. beetles and orthopterans). Seasonal effects in both prey diversity and volume were evident. Tree agamas are classic ambush foragers. They spent only 4% of their time moving and made few movements per minute (mean = 0.4). When stationary, adult tree agamas positioned themselves on tree trunks (34.7%), on lateral branches (41.8%) and occasionally, on the ground (23.4%). No evidence of trophic partitioning (intraspecific niche divergence hypothesis) was found and field observations revealed that males defend territories and engage in combat. This supports the idea that selection may be favouring larger head size in males, as an outcome of male contest competition. [source] Phenotypic plasticity of anuran larvae: environmental variables influence body shape and oral morphology in Rana temporaria tadpolesJOURNAL OF ZOOLOGY, Issue 2 2002Miguel Vences Abstract Environmental variables shaped the morphology of tadpoles of the common frog, Rana temporaria, in various ways at the Pyrenean locality Circo de Piedrafita. Examining only specimens in similar developmental stages, those from small ponds (with higher temperature and higher tadpole density) had lower growth rates, lower relative tail height, lower relative body width and fewer labial keratodonts and keratodont rows. The variation in keratodonts may have been caused by heterochrony related to the slower growth rate. The number of lingual papillae also differed between ponds but was not related to pond size. Higher predator densities caused a higher percentage of damaged tails and a lower relative tail length in specimens with apparently intact tails, probably as a result of incomplete regeneration after mutilations earlier in development. [source] Effect of different organotin compounds on DNA of gilthead sea bream (Sparus aurata) erythrocytes assessed by the comet assay,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2002Rosita Gabbianelli Abstract The ,comet' assay appears to be a promising tool for estimating DNA damage at the single cell level. We used this test to evaluate the effect of organotin compounds on sea bream nucleated erythrocytes. The tributyltin chloride (TBTC), dibutyltin chloride (DBTC) and monobutyltin chloride (MBTC) employed in this study show different genotoxicities. TBTC and DBTC have pronounced effects on tail length, tail intensity and tail moment, though TBTC is more efficient in producing DNA damage. MBTC leads to a fast genotoxic effect that does not change with the incubation time. The data obtained are important for the analysis of the environmental risks produced by organotin compounds used as antifouling agents in marine paints and as biocides in agriculture. Copyright © 2002 John Wiley & Sons, Ltd. [source] A combination of soy isoflavone supplementation and exercise improves lipid profiles and protects antioxidant defense-systems against exercise-induced oxidative stress in ovariectomized ratsBIOFACTORS, Issue 4 2007Hea Young Oh Abstract Menopause is often accompanied with weight gain, metabolic lipid abnormalities, and oxidative stress. In this study, we investigated the combined effects of exercise and soy isoflavone supplemention on the lipid profiles and antioxidant capacities of ovariectomized rats. Twenty-five female Sprague-Dawley rats were divided into 5 groups: sham-operated, ovariectomized (OVX), OVX with exercise (OVX + EX), OVX with soy isoflavone supplementation (OVX + ISO), and OVX with both soy isoflavones and exercise (OVX + ISO + EX). After 12 weeks of intervention, antioxidant status was evaluated in collected blood samples by the ferric reducing ability of plasma (FRAP), glutathione (GSH) content, and sodium oxide dismutase (SOD) activity. DNA damage in the lymphocytes was determined using alkaline single-cell gel electrophoresis (the Comet assay). Although there were no significant differences in weight gain and food intake, weight gain was lower in OVX + EX, OVX + ISO, and OVX + ISO + EX than in OVX. OVX + EX, OVX + ISO, and OVX + ISO + EX showed a significant decrease in total cholesterol, triglycerides, and LDL-cholesterol compared to OVX. The soy isoflavone supplemented group had significantly increased FRAP values and GSH contents in contrast to no changes in the exercised group, whereas exercise markedly increased SOD activity and H2O2 -induced DNA tail length and tail moment. Exercise with soy isoflavone supplementation significantly increased FRAP values and had no difference on SOD activity, including DNA damage. These results demonstrate that a combined treatment of moderate exercise and soy isoflavone supplementation could exert a beneficial effect on weight control and lipid profiles, and offer protection from exercise-induced oxidative stress in postmenopausal women. [source] Fluctuations in the incubation moisture environment affect growth but not survival of hatchling lizardsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010TRAVIS R. ROBBINS Few studies have collected longitudinal data that follow the complete microevolutionary path of an organism linking sources of variation (e.g. environmental versus genetic) to a trait and its subsequent relationship with fitness. Identifying the links within this pathway is imperative for understanding the ecological relevance of effects found at the phenotypic level. Furthermore, experimental studies that examine parts of the pathway in ectothermic organisms often fail to mimic the complexities of the natural developmental environment. Temperature and moisture conditions in reptile nests, for example, can fluctuate greatly on a seasonal and daily basis. Despite the potential effects of fluctuating environments, the vast majority of studies have held environmental treatments constant during the developmental period. We investigated the effects of fluctuating moisture regimes during incubation on eggs, hatchling phenotypes, and subsequent survival in the eastern fence lizard Sceloporus undulatus. Moisture fluctuations during embryonic development caused water absorption by eggs to follow the environmental availability of moisture. Initial hatchling tail length was affected by the pattern of moisture fluctuations, and hatchling growth rates in fluctuating treatments were significantly faster than those in a constant treatment, resulting in larger hatchlings after 4 weeks. A release,recapture experiment conducted in the field did not detect a treatment effect on survival despite the larger body sizes. In summary, although fluctuations affected water absorption by eggs and some hatchling traits, these effects did not have subsequent fitness consequences. The results obtained suggest that egg and hatchling survival are buffered against natural soil moisture fluctuations during incubation, even when egg and hatchling traits are significantly affected. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 89,102. [source] Seasonal monogamy and multiple paternity in a wild population of a territorial reptile (tuatara)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009JENNIFER A. MOORE Investigating the mating system of a population provides insight into the evolution of reproductive patterns, and can inform conservation management of threatened or endangered species. Combining behavioural and genetic data is necessary to fully understand the mating system and factors affecting male reproductive success, yet behavioural data are often difficult to collect for threatened species. In the present study, we use behavioural data and paternity analyses to characterize the mating system of a high density population of a long-lived, ancient reptile (tuatara, Sphenodon punctatus). We further investigate the phenotypic traits (including body size, body condition, tail length, and ectoparasite load) that affect male reproductive success. Our behavioural data reflect a seasonally monogamous system with low levels of polyandry and polygyny that are consistent with male mate guarding. Male reproduction is highly skewed (only 25,30% of males are successful), and body size is the primary predictor of male reproductive success. Based on the genetic data, multiple paternity was found in only 8% of clutches, and the results of the paternity analyses showed monandrous clutches from socially polyandrous females. Our behavioural and genetic results revealed complexities in female mating patterns that support the potential for cryptic female choice or sperm competition. This warrants further experimental investigation into the mechanisms underlying reptile fertilization and the disparities between social and genetic polyandry in wild populations. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 161,170. [source] The evolution of bipedal postures in varanoid lizardsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2009GORDON W. SCHUETT The bipedal posture (BP) and gait of humans are unique evolutionary hallmarks, but similar stances and forms of locomotion have had enormous influences on a range of phylogenetically diverse tetrapods, particularly dinosaurs and birds, and a range of mammalian lineages, including non-human apes. The complex movements involved in bipedalism appear to have modest evolutionary origins, and it is presumed that a stable and erect posture is a prerequisite for erect strides and other bipedal movements. Facultative bipedalism in several lineages of lizards is achieved by running, but some varanid lizards (genus Varanus) exhibit BPs without running. In these cases, BPs (BPstanding) are not used as a form of locomotion; rather, BPstanding is associated with defensive displays, and such postures also probably permit better inspection of the environment. Yet, in other varanids, BPs have been observed only during combat episodes (BPcombat), where both contestants rise together and embrace in the so-called clinch phase. Numerous other species, however, show neither type of BP. Past researchers have commented that only large-bodied varanids exhibit BP, a behaviour that appears to show phylogenetic trends. We termed this idea the King,Green,Pianka (KGP) bipedal hypothesis. In this article, we address two main questions derived from the KGP hypothesis. First, what is the phylogenetic distribution of BP in Varanus and close relatives (varanoids)? Second, is BP positively correlated with the phylogenetic distribution of large body size (e.g. snout,vent length, SVL)? In addition, we asked a related question: do the lengths of the femur and tail show body size-independent adaptive trends in association with BP? Because varanid species that show BPstanding also use these postures during combat (BPcombat), both types of BP were analysed collectively and simply termed BP. Using comparative phylogenetic analyses, the reconstruction of BP required three steps, involving a single gain and two losses. Specifically, BP was widespread in the monophyletic Varanus, and the single gain occurred at the most recent common ancestor of the African clade. The two losses of BP occurred in different clades (Indo-Asian B clade and Indo-Australian Odatria clade). BPs are absent in the sister group to Varanus (Lanthanotus borneensis) and the other outgroup species (Heloderma spp.). Our phylogenetic reconstruction supports the KGP prediction that BP is restricted to large-bodied taxa. Using the Hansen model of adaptive evolution on a limited, but highly relevant morphological dataset (i.e. SVL; femur length, FL; tail length, TL), we demonstrated that these characters were not equivalent in their contribution to the evolution of BP in Varanus. SVL was significantly correlated with BP when modelled in a phylogenetic context, but the model identified random processes as dominant over adaptive evolution, suggesting that a body size threshold might be involved in the evolution of BP. A Brownian motion (BM) model outperformed the selection model in our analysis of relative TL, suggesting that TL and BP evolved independently. The selection model for relative FL outperformed the BM model, indicating that FL and BP share an adaptive history. Our non-phylogenetic analyses involving regression residuals of FL and TL vs. SVL showed no significant correlation between these characters and BP. We suggest that BP in Varanus provides a convergent or analogue model from which to investigate various forms of bipedalism in tetrapod vertebrates, especially other reptiles, such as theropod dinosaurs. Because BPstanding in varanids is possibly an incipient stage to some form of upright locomotion, its inclusion as a general model in evolutionary analyses of bipedalism of vertebrates will probably provide novel and important insights. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 652,663. [source] Experimental evidence for female choice and energetic costs of male tail elongation in red-collared widowbirdsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2005SARAH R. PRYKE The black nuptial plumage of the highly polygynous male red-collared widowbird (Euplectes ardens) comprises a red carotenoid-based collar patch and a long graduated tail (c. 22 cm). Tail length was the strongest predictor of male mating success in a previous selection analysis, motivating this experimental test of the relative importance of tail plumes in male contest competition and female choice. Males were assigned to either a short (12.5 cm) or control (20 cm) tail manipulation prior to territory establishment. Male contest competition was unaffected by the tail treatments as the shortened- and control-tailed males were equally successful in acquiring territories of similar size and quality. In contrast, however, although the longer-tailed control males spent less time in flight and courtship displays, they attracted significantly more prospecting and nearly three times as many nesting females to their territories compared to the short-tailed males. In further support of tail length as the primary mate choice cue, none of the other measured and potential female cues (e.g. body size, collar colorimetrics, territorial behaviours or territory quality) influenced male reproductive success. In addition to potentially increasing detectability (,signal efficacy'), the long tail is also a likely indicator of male quality (,signal content'). Despite the higher activities of short-tailed males, control-tailed males showed a steeper decline in condition (relative body mass) during the breeding season. Furthermore, both short- and control-tailed residents lost more condition than did the short- and control-treated floaters (males not establishing territories), suggesting an interaction between tail length and the costs of territory acquisition, defence and courtship displays. These results confirm the role of mate choice and honest quality advertising as the main selection pressures behind elongated tails in widowbirds. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 35,43. [source] DNA damage in Pakistani pesticide-manufacturing workers assayed using the Comet assayENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 8 2006Javed A. Bhalli Abstract The production and use of chemical pesticides has increased in recent years. Although the increased use of pesticides may benefit agriculture, they are also the potential source of environmental pollution, and exposure to pesticides can have negative consequences for human health. In the present study, we have assessed DNA damage in blood leukocytes from 29 Pakistani pesticide-factory workers and 35 controls of similar age and smoking history. The workers were exposed to various mixtures of organophosphates, carbamates, and pyrethroids. DNA damage was measured with the single cell gel electrophoresis (SCGE) assay or Comet assay, using the mean comet tail length (,m) as the DNA damage metric. Exposed workers had significantly longer comet tail lengths than the controls (mean ± SD 19.98 ± 2.87 vs. 7.38 ± 1.48, P < 0.001). Of the possible confounding factors, smokers had significantly longer mean comet tail lengths than nonsmokers and exsmokers for both the workers (21.48 ± 2.58 vs.18.37 ± 2.28, P < 0.001) and the controls (8.86 ± 0.56 vs. 6.79 ± 1.31, P < 0.001), while age had a minimal effect on DNA damage (P > 0.05 and P < 0.05 for workers and controls, respectively). The results of this study indicate that occupational exposure to pesticides causes DNA damage. Environ. Mol. Mutagen., 2006. © 2006 Wiley-Liss, Inc. [source] Adaptive Offspring Sex Ratio Depends on Male Tail Length in the GuppyETHOLOGY, Issue 11 2006Kenji Karino A biased sex ratio in a brood is considered to be an adaptive strategy under certain circumstances. For example, if the expected reproductive success of one sex is greater than that of the other, parents should produce more offspring of the former sex than the latter. A previous study has documented that in the guppy, Poecilia reticulata, the female offspring of males possessing proportionally longer tails exhibit smaller body sizes and show decreased reproductive outputs than those of males having shorter tails. On the other hand, the total lengths of the male offspring of the long-tailed males are larger because of their longer tails; consequently, they exhibit greater sexual attractiveness to females. Therefore, it has been hypothesized that this asymmetry in the expected reproductive success between the male and female offspring of long-tailed males may result in a biased sex ratio that is dependent on the tail lengths of their fathers. This hypothesis was tested in the present study. The results showed that the females that mated with long-tailed males produced more male offspring than those that mated with short-tailed males. Logistic regression analysis showed that the ratio of tail length to the standard length of the fathers is a determinant factor of the sex of their offspring. These results suggest that the manipulation of the offspring sex ratios by parents enhances the overall fitness of the offspring. [source] Molecular Tailored Histidine-Based Complexing Surfactants: From Micelles to HydrogelsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2009Patrick Gizzi Abstract Novel histidine-based complexing surfactants, designed as AA-His-EOm -Cn, containing trifunctional moduli (peptidic/hydrophilic/hydrophobic) were synthesized by a modular step-by-step procedure, which allowed easy structural changes, and consequently correlations between their molecular structures and their self-assembling properties could be established. Thus, micelles or hydrogels could be obtained by simply modifying the hydrophobic tail lengths or the junction between the different moduli of the designed compounds. At low pH values, all compounds were surface active in aqueous solutions. At higher pH values, in the range 8,10, micellization took place for decyl compounds (n = 10), whereas hydrogelation occurred for longer chain lengths (n = 12, 14), and this, at very-low concentrations of surfactant (<0.3 wt.-%), could thus act as low molecular weight gelator (LMWG). The driving forces for gel formation were noncovalent intermolecular interactions such as ,-stacking and hydrophobic and hydrogen-bonding interactions.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Limb and tail lengths in relation to substrate usage in Tropidurus lizardsJOURNAL OF MORPHOLOGY, Issue 2 2001Tiana Kohlsdorf Abstract A close relationship between morphology and habitat is well documented for anoline lizards. To test the generality of this relationship in lizards, snout-vent, tail, and limb lengths of 18 species of Tropidurus (Tropiduridae) were measured and comparisons made between body proportions and substrate usage. Phylogenetic analysis of covariance by computer simulation suggests that the three species inhabiting sandy soils have relatively longer feet than do other species. Phylogenetic ANCOVA also demonstrates that the three species inhabiting tree canopies and locomoting on small branches have short tails and hind limbs. These three species constitute a single subclade within the overall Tropidurus phylogeny and analyses with independent contrasts indicate that divergence in relative tail and hind limb length has been rapid since they split from their sister clade. Being restricted to a single subclade, the difference in body proportions could logically be interpreted as either an adaptation to the clade's lifestyle or simply a nonadaptive synapomorphy for this lineage. Nevertheless, previous comparative studies of another clade of lizards (Anolis) as well as experimental studies of Sceloporus lizards sprinting on rods of different diameters support the adaptive interpretation. J. Morphol. 248:151,164, 2001. © 2001 Wiley-Liss, Inc. [source] Morphological and morphometric attributes of epididymal and testicular spermatozoa following surgical sperm retrieval for obstructive and nonobstructive azoospermiaANDROLOGIA, Issue 6 2003Dr. S. Wood Summary. Whilst the morphological (shape) and morphometric (sperm head size) attributes of ejaculated spermatozoa have been well studied, the morphological and morphometric qualities of testicular and epididymal spermatozoa retrieved from males with obstructive and nonobstructive azoospermia is much less documented. We wished to examine the effect of aetiology of azoospermia and site of retrieval on the attributes of retrieved spermatozoa. This was a prospective observational study of 30 consecutive successful sperm retrievals, six for nonobstructive azoospermia and 24 for obstructive, of which five were retrieved from the epididymis and the remainder from the testis. The proportion of morphologically normal testicular spermatozoa in patients with obstructive and nonobstructive azoospermia was not significantly different (7% versus 7.6%, P = 0.97). Testicular spermatozoa from males with obstructive azoospermia showed an increase in frequency of sperm with small heads [47/180 (26%) versus 97/909 (11%), P = 0.036] as well as small acrosome and increasing vacuole formation over nonobstructive spermatozoa. Similarly, there was a significant increase in tail deformities and decreases in tail lengths in sperm from males with nonobstructive azoospermia. Epididymal spermatozoa showed significantly greater proportion of morphologically normal spermatozoa than testicular (20% versus 13%, P = 0.001) as well as a significant increase in acrosome vacuoles. Furthermore, morphometrically epididymal spermatozoa displayed with smaller head length, width and area than testicular spermatozoa. Testicular spermatozoa from obstructive azoospermia displayed significantly less tail defects (35% versus 57%, P = 0.003) as well as significantly longer tail lengths (30.6 ,m versus 10.7 ,m). These morphological and morphometric differences between epididymal and testicular and obstructive and nonobstructive spermatozoa may represent part of the natural maturation process. There were no associations between any morphological or morphometric abnormality with any significant parameter in subsequent use in ICSI. [source] Syntheses, Phase Behavior, Supramolecular Chirality, and Field-Effect Carrier Mobility of Asymmetrically End-Capped Mesogenic OligothiophenesCHEMISTRY - A EUROPEAN JOURNAL, Issue 14 2009Qingwei Meng Dr. Abstract Supramolecular chirality and liquid crystalline OFET: Achiral end-capped oligothiophenes can be tuned to exhibit supramolecular chirality with unique striped textures showing distinct circular dichroism signals as well as a highly ordered SmE phase that leads to high hole carrier mobility. A novel series of asymmetrically end-capped mesogenic oligothiophenes, with various oligothiophene core lengths, alkoxy tail lengths, and molecular polarities through introducing alkylsulfanyl or alkylsulfonyl functionalities as the terminal group, have been synthesized by palladium-catalyzed Suzuki cross-coupling and Kumada cross-coupling reactions as key steps. For the single end-capped oligothiophenes, CmO-Ar-OT(4)-H in which m=10, 12, 14, 16, and 18, all of these oligomers exhibited a broad temperature range of highly ordered smectic E and enantiotropic nematic phases, apart from the one with the longest octadecyloxy tail. For the double end-capped series C10O-Ar-OT(n)-R, R=Ph-SC6 or Ph-SO2C6 in which n=1, 2, 3, and 4, oligomers with more than one thiophene ring exhibited smectic A and smectic C phases, various crystal polymorphs and/or unusual low-temperature condensed phases. In the nonpolar, alkylsulfanylphenyl-substituted oligothiophene series, both the crystal/solid melting point and mesogenic clear point increased significantly with an increasing oligothiophene conjugation length. In the polar, alkylsulfonylphenyl-substituted oligothiophene series, all the oligomers showed increased melting points, but decreased mesogenic temperature intervals than those of their corresponding alkylsulfanyl counterparts. Remarkably, two different helical structures showing distinct striated textures or striped patterns were observed with a pitch of several to tens of micrometers under a polarized optical microscope upon cooling from their preceding fluidic smectic phases. The unusual twisted smectic layer structures in the thin solid films exhibiting distinct supramolecular chirality of both handednesses, revealed by circular dichroism measurements, were further confirmed by XRD analyses characterized by a sharp layer reflection together with its higher orders and diffuse wide-angle scatterings. In addition, initial studies showed that the highly ordered smectic phase of the single end-capped oligothiophenes can be utilized to improve field-effect charge mobility. C10O-Ar-OT(4)-H showed a hole mobility of 0.07,cm2,V,1,s,1 when deposited on octyltrichlorosilane-treated substrates at 140,°C and the on/off current ratios reached 5×105; on the other hand, its mobility was only 8×10,3,cm2,V,1,s,1 on the same substrate when deposited at room temperature. [source] | ||||||||||||||||||||||||||||