Oral deformities in tadpoles (Ranacatesbeiana) associated with coal ash deposition: effects on grazing ability and growth

1. Tadpoles of the bullfrog ( Rana catesbeiana ) collected in a coal ash deposition basin (contaminated with As, Cd, Cr, Cu, Se and other elements) and a downstream drainage swamp had a reduced number of labial teeth and deformations of labial papillae when compared with tadpoles from reference areas. Tadpoles from the coal ash-affected areas had 90% fewer teeth in anterior tooth row number 2 and 40% fewer teeth in posterior row number 1 than reference animals. In the deposition basins, drainage swamp and reference ponds, respectively, 96.2, 85.1 and 2.9% of tadpoles had oral deformities.
2. Tadpoles with deformities were less able to graze periphyton than were normal tadpoles, when tested in the laboratory. When presented with periphyton as a sole food source, tadpoles with deformed teeth had lower (negative) growth rates than those with normal teeth, which had slightly positive growth rates. When particulate food was also available, tadpoles grew well regardless of deformities.
3. It appears that the morphological deformities associated with this coal ash-polluted environment can have ecological ramifications for the affected organisms by limiting the type of food that can be consumed and the ability to grow when multiple food types are unavailable.     

The effects of kinship and density on growth and metamorphosis of the bronze frog (Rana temporalis) tadpoles

  Five clutches of Rana temporalis eggs collected along a stream were reared separately until formation of Gosner stage 25 tadpoles. The effect of kinship and density was then studied by rearing ten siblings in 1 (sib 1) or 5 (sib 5) l water, and mixed rearing of ten tadpoles (2 from each of the 5 clutches) in 1 (mix 1) or 5 (mix 5) l water; each group replicated five times. In all the groups tadpoles showed a sigmoid growth curve. Both kinship and density interacted to affect mean proportions of individuals reaching metamorphic climax (MC), mean body mass, and size frequency at MC (day 79). The proportion of tadpoles reaching MC was highest in sib 5 (82%) followed by mix 5 (77%), sib 1 (73%), and mix 1 (64%) groups. Crowding plus mixing significantly lowered the median developmental stage mean body mass and broadened the spectrum of developmental stages or size classes at MC. The size difference of individuals at MC was inversely related to density of rearing. Frequency of different developmental stages was comparable in sib 1, sib 5, and mix 5 groups. Interestingly, small individuals were significantly greater in number in the mix 1 group compared to sib 1. The above findings suggest that genotypic heterogeneity in conjunction with crowding retards growth rate of tadpoles in comparison with those reared in a genetically homogenous (sib) environment. Further, they suggest that the adverse effect of mixed rearing is context dependent. Received: 12 April 1999 / Received in revised form: 16 June 1999 / Accepted: 18 June 1999     

壬基酚对中国林蛙蝌蚪生长发育的毒性效应

为评价壬基酚对中国林蛙(Rana chensinensis)蝌蚪的急性毒性,将26～28期的中国林蛙蝌蚪暴露于浓度为0.05～0.5 mg·L-1壬基酚(NP)的水体中进行急性毒性试验.结果表明:24、48、72、96h蝌蚪的死亡几率与浓度对数的回归方程分别为y=8.4087χ 10.202、y=9.5104χ 11.745、y=10.284χ 12.498、y=10.619,χ 13.095;半数致死浓度(LC50)分别为0.24、0.20、0.19、0.17 mg·L-1;安全浓度(SC)为0.017mg·L-1;96h的LC0为0.14 mg·L-1.证明林蛙蝌蚪的死亡几率与一定范围的NP浓度呈线性正相关.为探讨低浓度壬基酚对中国林蛙蝌蚪生长发育的影响,将26期林蛙蝌蚪分别在100、60、30、10μg·L-1 NP的水体中连续暴露直至完全变态,并以3、0.3 μg·L-1雌二醇(E2)作为阳性对照,分别统计林蛙蝌蚪暴露于NP和E2,中20、40d和完成变态后幼蛙的体质量、全长以及从26期到完全变态所需的时间.结果表明,NP浓度在100 μg·L-1以下,对林蛙蝌蚪不能致死.100、10 μg·L-1NP与3 μg·L-1E2的效应相似,均可滞后蝌蚪变态时间,降低蝌蚪变态后幼蛙的体质量.说明NP浓度在100μg·L-1以下不直接损伤蝌蚪机体,但可以通过干扰内分泌活动影响林蛙幼体的生长发育.     

Acute and chronic effects of Cr(VI) on Hypsiboas pulchellus embryos and tadpoles

In the last few years there has been great concern about declines in the abundance of several species of amphibians around the world. Among amphibians, anurans have a biphasic life cycle, with aquatic tadpoles and generally terrestrial adults, and they have an extremely permeable skin, making them excellent indicators of the health of the environment. A number of different causes have been suggested for the global decline of anurans, the pollution of their habitat by chemical stressors being considered one of the major factors. Among chemical stressors, heavy metals are known for their high toxicity at very low concentrations. This study assessed short- (96 h, 'acute') and long-term (1272 h, 'chronic') exposure to Cr(VI) at lethal (3 to 90 mg 1(-1)) and sublethal concentrations (0.001 to 12 mg 1(-1)) on Hypsiboaspulchellus (previously called Hyla pulchella; see Faivovich et al. 2005) tadpoles (Fam. Hylidae) from central eastern Argentina. Fertilized eggs collected from a clean pond near La Plata (Buenos Aires Province) were used for acute and chronic toxicity testing. Assays were done under controlled laboratory conditions. Results of chronic exposure were used to assess the effect of factors such as toxicant concentration and age of organisms at the beginning of exposure on the response variables (growth, development and survival until metamorphosis). Results indicated a higher sensitivity to Cr(VI) of individuals first exposed as tadpoles than those first exposed as embryos during acute and chronic exposure. Exposure to the highest sublethal concentrations (6 to 12 mg 1(-1)) of the toxicant showed early inhibitory effects on growth of all treated organisms compensated at longer exposure periods with an increase in the growth rate compared to the control groups.     

Induction of apoptotic effects of anti-proliferative zeolite X from coal fly ash on cervical cancer (HeLa) cell lines

The synthesised zeolite X from coal fly ash showed significant cytotoxic activity in contradiction of HeLa cells (cervical cancer) in a concentration-dependent way at concentrations ranges from 200 µg to 0.781 µg/ml as shown by MTT assay and failed to cause cytotoxic effect in normal cells (Gh239). Cell cycle analysis exposed that zeolite X (10 and 15 µg/ml) endorses cell growth inhibition by inducing G2/M phase arrest in HeLa cells as observed using flow cytometry. The confocal microscopic results depicted increased early apoptotic related changes in HeLa cell lines induced by zeolite X at a dosage of 10, 15 and 20 µg/ml. Zeolite X at a dosage of 10, 15 and 20 µg/ml in HeLa cells showed fragmentation of DNA by ladder pattern thereby indicates that cell death is related with apoptosis. By the increase of Bax/Bcl-2 ratio, zeolite X leads to the caspase-3 and caspase-9 activation and allow the cells to enter apoptosis. These collective results evidently showed that the influence of mitochondria-mediated signalling pathway in zeolite X induced apoptosis and intensely delivered investigational suggestion for the use of zeolite X as a significant curative agent in the preclusion and therapy of human cervical carcinoma.

     

Carry-over effects of embryonic acid conditions on development and growth of Rana temporaria tadpoles

1. Conditions experienced during the early stages of development may have carry‐over effects on performance during later life. The egg laying period and embryonic development of temperate and boreal zone amphibians often coincides with peak acidity resulting from spring snow‐melt, but the effects of acid conditions during embryonic stage on subsequent performance are unknown. 2. We investigated the potential carry‐over effects of acidity during the embryonic stage on performance up to metamorphosis in the common frog (Rana temporaria) tadpoles. There were four combinations of acid (4.5) and neutral (7.5) pH treatments applied to the egg and larval stages in a factorial laboratory experiment. In addition, we studied the difference in embryonic and larval tolerance of acidity between two populations originating from circumneutral (pH 6.6) and acidic conditions (pH 4.8). 3. The effects of acid conditions during the embryonic stage were sublethal, as indicated by delayed development and reduced size. Under acid conditions, tadpoles that had been raised in neutral water as embryos at first grew more slowly than tadpoles raised under acid conditions as embryos. At metamorphosis, no effects of embryonic acidity were detectable indicating that tadpoles were able to compensate fully for the initial reduction in growth. 4. Acid conditions during the larval period had a strongly negative effect on survival, size and age at metamorphosis. The amount of food consumed was lower under acid conditions, suggesting that reduced food consumption was at least partly responsible for the negative effects. 5. Although the two populations differed in the length of larval period, there was no indication of a differential response to the treatments in any of the metamorphic traits studied. 6. These results suggest that, although moderate acid conditions during embryonic development affect growth and development negatively, this influence does not persist after conditions have returned to normal. However, even moderately acid conditions during the larval period may have a strong negative influence on survival and performance of the tadpoles.     

Coloration signals the ability to cope with elevated stress hormones: effects of corticosterone on growth of barn owls are associated with melanism

Stressful situations during development can shape the phenotype for life by provoking a trade-off between development and survival. Stress hormones, mainly glucocorticoids, play an important orchestrating role in this trade-off. Hence, how stress sensitive an animal is critically determines the phenotype and ultimately fitness. In several species, darker eumelanic individuals are less sensitive to stressful conditions than less eumelanic conspecifics, which may be due to the pleiotropic effects of genes affecting both coloration and physiological traits. We experimentally tested whether the degree of melanin-based coloration is associated with the sensitivity to an endocrine response to stressful situations in the barn owl. We artificially administered the mediator of a hormonal stress response, corticosterone, to nestlings to examine the prediction that corticosterone-induced reduction in growth rate is more pronounced in light eumelanic nestlings than in darker nest mates. To examine whether such an effect may be genetically determined, we swapped hatchlings between randomly chosen pairs of nests. We first showed that corticosterone affects growth and, thus, shapes the phenotype. Second, we found that under corticosterone administration, nestlings with large black spots grew better than nestlings with small black spots. As in the barn owl the expression of eumelanin-based coloration is heritable and not sensitive to environmental conditions, it is therefore a reliable, genetically based sign of the ability to cope with an increase in blood corticosterone level.     

Long-term effects of sheep grazing on giant hogweed (Heracleum mantegazzianum)

A meadow dominated by a mature, flowering stand of Giant Hogweed (Heracleum mantegazzianum) was grazed by sheep in the years 1987–1993. After two years Giant Hogweed cover was much reduced and a typical meadow vegetation was established. By 1993 Giant Hogweed was completely eliminated though total species diversity was much reduced. Soil sampled from the grazed area developed no Giant Hogweed seedlings in a germination test and contained no viable seeds of the species. In contrast soil from adjacent stands produced numerous seedlings with a peak emergence from samples taken after the winter. Seeds collected in October showed a viability in tetrazolium test of 88%. Germination averaged 22% after storage at room temperature and 25% following three weeks treatment at –18°C. It was concluded that the persistence of Giant Hogweed seeds in Danish meadow soils is less than seven years.     

Effect of coal ash on growth and metal uptake by some selected ectomycorrhizal fungi in vitro

Six isolates of ectomycorrhizal fungi namely, Laccaria fraterna (EM-1083), Pisolithus tinctorius (EM-1081), Pisolithus tinctorius (EM-1290), Pisolithus tinctorius (EM-1293), Scleroderma verucosum (EM-1283), and Scleroderma cepa (EM-1233), were grown on three variants of coal ash, namely electrostatically precipitated (ESP) ash, pond ash, and bottom ash moistened with Modified Melin-Norkans (MMN) medium in vitro The colony diameter reflected the growth of the isolates on the coal ash. Metal accumulation in the mycelia was assayed by atomic absorption spectrophotometry. Six metals, namely aluminum, cadmium, chromium, iron, lead, and nickel, were selected on the basis of their abundance in coal ash and toxicity potential for the present work. Growth of vegetative mycelium on fly ash variants and metal accumulation data indicated that Pisolithus tinctorius (EM-1290) was the most tolerant among the isolates tested for most of the metals. Since this isolate is known to be mycorrhizal with Eucalyptus, it could be used for the reclamation of coal ash over burdened sites.     

Evolution of erect growth forms in domesticated wheats: possible effects of grazing

Summary Wild wheats tend to have a prostrate growthform during the early part of their vegetative growth phase. However, at a later stage the leaves and spike-bearing stalks change the pattern of growth and develop in an erect position. Domesticated wheats develop differently, with an erect growth form dominating the entire growth phase.It is suggested that heavy grazing, especially during early winter months might have played a role in the eradication of spontaneously appearing erect mutants of wild wheat. Such mutants increased in frequency only under domestication.     

酚类物质对中国林蛙蝌蚪生长发育的毒性效应

中国林蛙蝌蚪对水环境有极强的依赖性,水环境中的酚类物质可以通过中国林蛙蝌蚪的呼吸系统和皮肤进入其体内,影响蝌蚪的存活状况、生长发育和生理生化指标。因此中国林蛙蝌蚪可以用作监测水体环境的指示物种。从壬基酚、辛基酚和双酚A等酚类物质对中国林蛙蝌蚪生长发育的毒性效应进行阐述,为酚类污染物对两栖动物生长发育影响机理的深入研究奠定基础,为中国林蛙蝌蚪的生态保护和水环境监测提供科学依据。     

Morphology and feeding in tadpoles of Ceratophrys cranwelli (Anura: Leptodactylidae)

This paper provides data on the skeleton, musculature, buccal apparatus, buccopharyngeal cavity and diet of Ceratophrys cranwelli tadpoles, and attempts to contribute to the knowledge of relations between morphology and ecology in anuran larvae. Both in morphological characters and feeding habits, these tadpoles are very similar to other species within the genus. They possess many of the structural features usually found in predaceous tadpoles: strong, keratinized jaw sheaths and keratodonts, reduced buccal papillation, high values of in‐lever arm proportion and buccal floor area, well‐developed ceratohyals, and hypertrophied jaw muscles. Food sources consist of other tadpoles, microcrustaceans, larvae of insects, plant fragments, as well as rotifers and microalgae. As facultative carnivores, they are likely to play an important role in regulating the aquatic communities of the ephemeral ponds where they develop.     

Factors associated with detrimental effects of rhizobacteria on plant growth

Some of the factors interfering with the specific response of young common bean plants to two rhizosphere fluorescent pseudomonads were studied. These two bacterial strains produced symptoms in foliar plant parts and reduced yield in beans and several other plant species when inoculated on roots. Sensitivity in the plants subjected to bacterial application was highest at early growth stages (up to ten days old plants) giving typical symptoms for each strain in first expanding leaves and typically stunted plant growth. Symptoms to some extent also appeared on plants treated at the age of 2–3 weeks and the fresh shoot weight was affected also in such plants. Deleterious effects of the tested bacteria were found to be related to the level of inoculum (cfu/ml) used and presence or absence of certain nutrients in the bacterial suspensions used for inoculation. The two tested strains differed in nutritional requirements for affecting plant growth. One strain needed sucrose only. The other tested strain required peptone or yeast extract in addition to sucrose to induce typical symptoms and significant yield reductions. Supply of peptone as the only nutrient source to the bacterial suspensions eliminated the deleterious effects of both bacterial strains as tested on beans under nonsterile conditions. The two strains are assumed to affect test plants by different modes of action.     

The porcine fat mass and obesity associated (FTO) gene is associated with fat deposition in Italian Duroc pigs

In humans, common variants in the fat mass and obesity associated ( FTO ) gene are associated with body mass index and obesity. Here we sequenced exon 4, parts of introns 3 and 4 and two portions of the 3'-untranslated region of the porcine FTO gene in a panel of nine pigs of different breeds and identified three SNPs. Allele frequencies of the g.276T>G ( AM931150 ) mutation were studied in seven pig breeds. This mutation was used to linkage-map FTO to SSC6. Association analyses between the g.276T>G polymorphism and several traits [pH of semimembranosus muscle and estimated breeding values (EBV) for average daily gain, back fat thickness, lean cuts, ham weight and feed:gain ratio] were carried out in 257 sib-tested Italian Large White pigs. Only feed:gain ratio showed P  <   0.05. A selective genotyping approach was applied, analysing two extreme and divergent groups of Italian Large White pigs selected on the basis of back fat thickness EBV (50 with most positive and 50 with most negative values). Fisher's exact test (two-tailed) was not significant when comparing the allele frequencies of these two groups. The same approach was used in the Italian Duroc breed for which two extreme and divergent groups of animals were selected according to visible intermuscular fat EBV. Differences of allele frequencies between these two groups were highly significant ( P  <   0.00001, P  <   0.001 and P  <   0.0001, considering all animals or only two- or three-generation unrelated animals respectively), indicating association between the analysed FTO marker and intermuscular fat deposition.     

Latent soil effects of grazing and ammonium deposition on Deschampsia flexuosa tillers inserted and grown in heather moorland soil

Upland heather moorlands support a range of increasingly rare and threatened biota, making them a priority habitat for conservation and restoration. Over-grazing and nitrogen deposition are two of the most important threats to maintaining these heather moorlands, yet there remains a paucity of research into their combined long-term effects. During the summer of 2008, we established an experiment within an existing research site at Pwllpeiran, mid-Wales. The original site, established in 1996, investigated long-term grazing and N deposition treatments (ammonium and nitrate) on heather moorland. Previous findings from the site, following a decade of treatment, suggested no significant, detectable impacts of treatments on soil C:N ratio and the foliar nitrogen of vegetation.The aim of our study was to investigate short- (2008) and long-term (1996–2008) N deposition treatment impacts, in combination with past grazing (1990–2007), on soil nutrient bioavailability. Soil cores were harvested and aboveground vegetation removed. Tillers of the grass Deschampsia flexuosa were planted into these cores which were then reciprocally transplanted back into the field experiment. The N deposition treatment was continued but grazing was excluded. D. flexuosa biomass changes were next assessed and leaf chemistry investigated using the metabolic fingerprinting method Fourier-transform infrared spectroscopy (FTIR) following three months of growth in the field (May–August 2008).Grazing treatment (on its own) had significant negative impacts on aboveground biomass and significant changes in plant chemistry were also revealed through the metabolic fingerprinting method Fourier transform infrared spectroscopy (FTIR). Short-term N deposition treatments during 2008 had no impacts on D. flexuosa growth or chemistry. There were also no detectable latent effects of long-term nitrate treatments on either growth or chemistry of D. flexuosa. However, plants grown in plots that had received long-term treatments of ammonium (NH₄⁺) had significantly lower poly-phenolic contents (revealed by FTIR) than plants grown in either nitrate (NO₃⁻) or control plots, suggesting detectable latent effects of N application in its reduced form. Further work needs to be undertaken to assess the relevance of residual soil nitrogen pools post N deposition and grazing.     

Digestive plasticity in tadpoles of the Chilean giant frog (Caudiverbera caudiverbera): factorial effects of diet and temperature

Anuran metamorphosis is one of the most spectacular processes in nature. Metamorphosis entails morphological transformations and extensive changes in feeding habits, such as transforming from an herbivore to a carnivore. This phenomenon is especially sensitive to environmental cues. We studied the phenotypic plasticity of intestinal morphology and enzyme activity in tadpoles of the Chilean giant frog Caudiverbera caudiverbera. We tested the effects of diet and temperature using a factorial design, which included a control of nontreated individuals. There was no significant effect of diet treatment (i.e., low- vs. high-quality diet) on any of the measured variables, including external morphology. We found significant effects of temperature on morphological traits. Temperature treatment also had significant effects on aminopeptidase-N and maltase activity. Both enzymes exhibited complex interactions with temperature along the intestine. Gut size varied significantly among temperatures, with intestines from warm-treated individuals smaller than the intestines from control and cold-treated tadpoles. Our findings suggest that phenotypic plasticity of intestinal morphology and physiology exists in larvae of this species, at least in response to temperature. However, we did not detect clear effects of diet or temperature on the timing of metamorphosis.