The use of coral nubbins in coral reef ecotoxicology testing

While there is an urgent demand to establish reliable ecotoxicological assays for reef corals, there has not been yet an available source material that can supply the high number of colony replicates needed for reliable tests. In past experiments, the major obstacle to obtaining as many fragments as possible had been the damage inflicted to donor colonies by pruning. In this paper, we present the application of coral nubbins, a novel source material for coral ecotoxicology assays. Nubbins from the branching Red Sea coral Stylophora pistillata (n>450) were used for evaluating the impacts of water soluble fractions from a crude oil, an oil dispersant and dispersed oil. Coral nubbins (minute coral fragments in the size of one to several polyps) harvested from a single colony are genetically identical to each other, may be obtained in any quantity needed and whenever research activities demand their use. Several dozens of nubbins can be obtained from a single small branch in branching coral species, a procedure that has minimal impact on donor genotypes. Nubbins production is a low cost procedure and requires limited maintenance space. Results of short and long-term acute ecotoxicological tests are revealed and discussed here, indicating the advantageous use of nubbins as ubiquitous coral material for toxicology assays and physiological studies.     

Oribatid mites: prospects for their use in ecotoxicology

Oribatid mites are a group of arthropods that have had remarkable evolutionary success with regard to species richness, variety of habitats colonized, life-cycle variation and reporductive patterns. The aim of this paper is to review some of the important features of Oribatida in relation to the possible use of these animals in ecotoxicological experiments. Their often sedentary way of living, combined with a narrow dependence on microhabitats qualify oribatids as potential indicator organisms for air and soil quality. Some species have been shown to be extremely sensitive to air pollutants such as SO₂ and NO₂. A low metabolic rate may be the driving force for slow development, low fertility, iteroparity and long adult life. Given these life-cycle characteristics, oribatids may be particularly vulnerable to intoxication by persistent contaminants. Work done on heavy metals suggests that the capacity for accumulation differs greatly between species. The camisiid Platynothrus peltifer accumulates high amounts of trace metals, specifically Mn. The toxicity of Cd, Cu and Pb has been studied in P. peltifer, demonstrating the necessity to consider egg production as a sensitive criterion. It is concluded that oribatid mites hold a great potential for use in ecotoxicology, due to the structural and functional complexity of their communities, and several peculiarities not found in other arthropods. The possibilities offered by this diverse group have not yet been fully employed by ecotoxicologists.     

The use of RAPD markers in Hordeum phylogeny.

The phylogenetic relationships among 39 wild Hordeum species, subspecies, and cultivated barley were investigated using RAPD markers as discriminating characters. Seventy-six RAPD fragments were generated using 12 single decameric primers of arbitrary nucleotide sequences. Amplification reactions resulted in fragments ranging in length between 200 and 2000 bp. Clearly resolved bands were scored for their presence or absence in a binary matrix. Amplified products were treated as independent characters to generate a phenogram using the NTSYS-PC package. Tree topology was generally found to be consistent with those based on morphological treatments. However, a few species like H. erectifolium, H. jubatum and, to a lesser extent, H. bulbosum occupied a position different from previous classifications. The results demonstrated that RAPD technology represents a useful and reliable tool for detecting polymorphism for phylogenetic studies. Key words : RAPD analysis, molecular markers, phylogenetic studies, Hordeum species, barley.     

The use of RAPD to characterize Bipolaris sorokiniana isolates

Bipolaris sorokiniana is a phytopathogenic fungus causing diseases of cereal crops such as common root rot, the leaf spot disease, seedling blight, and black point of the grain. Random-amplified polymorphic DNA (RAPD) assay was used to investigate the genetic diversity of 20 isolates collected from different cultivars in wheat-producing regions in Brazil. Seventy primers, with random nucleotide sequences, were tested. Reproducibility to amplify the genomic DNA of isolates was found for 30 of the 70 primers tested, generating between 1 and 17 fragments ranging from 0.35 to 2.0 kb (average size). The degree of similarity between samples was calculated through simple association and the dendrogram was assessed using the unweighted pair group method with arithmetical average. After the RAPD analyses 19 isolates were closely grouped, having a similarity coefficient of >or= 78%. Isolate I017 showed very low similarity coefficients, ranging between 38 and 46%. The RAPD analyses provided important information as to the degree of genetic variability and the relationship between the isolates investigated, revealing polymorphism and establishing electrophoretic profiles useful to characterize the phytopathogen.     

The use of RAPD analysis to classify Triticum accessions

 Crop germplasm collections contain a considerable percentage of misclassified accessions which may affect the use of germplasm for agricultural crop improvement. The objective of this study was to determine if random amplified polymorphic DNA (RAPD) analysis could be used to reclassify misclassified Triticum accessions. Twelve accessions suspected to be misclassified, based on morphological characters, as either macha or vavilovii wheat were studied using RAPD and cytological analyses. In the RAPD analysis, a dendrogram, based on Jaccard genetic similarity coefficients, grouped 5 dicoccum-like, 1 timopheevii-like, and 6 monococcum-like accessions with Triticum dicoccum, T. timopheevii, and T. monococcum accessions, respectively. These results were confirmed by the cytological analysis. A RAPD marker specific to the D genome was also detected. This study suggests that RAPD analysis can be used to classify germplasm and to distinguish some species in Triticum. Received: 12 June 1998 / Accepted: 18 August 1998     

微宇宙理论及其在生态毒理学研究中的应用

简述微宇宙理论,发展史和主要类型,并着重综述了微宇宙在生态毒理学研究中的主要应用情况,以及与实验室单物种试验和野外试验比较微宇宙的优缺点,并对微宇宙的未来发展趋势也作了简要讨论。     

Genetic ecotoxicology: The genotypic diversity approach

Organismal responses at the genetic level to exposure to environmental genotoxicants have been well documented. An elucidation of the molecular mechanisms involved with these responses, as well as an assessment of the changes that may occur to the genetic material, will provide an understanding of the potential for deleterious consequences at higher levels of biological organization. Moreover, modern procedures of molecular biology offer the hope that alterations and changes to genetic material can be readily detected.     

Proteomic applications in ecotoxicology

Within the growing body of proteomics studies, issues addressing problems of ecotoxicology are on the rise. Generally speaking, ecotoxicology uses quantitative expression changes of distinct proteins known to be involved in toxicological responses as biomarkers. Unlike these directed approaches, proteomics examines how multiple expression changes are associated with a contamination that is suspected to be detrimental. Consequently, proteins involved in toxicological responses that have not been described previously may be revealed. Following identification of key proteins indicating exposure or effect, proteomics can potentially be employed in environmental risk assessment. To this end, bioinformatics may unveil protein patterns specific to an environmental stress that would constitute a classifier able to distinguish an exposure from a control state. The combined use of sets of marker proteins associated with a given pollution impact may prove to be more reliable, as they are based not only on a few unique markers which are measured independently, but reflect the complexity of a toxicological response. Such a proteomic pattern might also integrate some of the already established biomarkers of environmental toxicity. Proteomics applications in ecotoxicology may also comprise functional examination of known classes of proteins, such as glutathione transferases or metallothioneins, to elucidate their toxicological responses.     

Physiological parameters in ecotoxicology.

1. Regulated physiological parameters are normally maintained at a constant level by regulatory mechanisms. Acute toxic effects develop whenever a pollutant causes a regulated parameter to be displaced beyond tolerated limits, and thus, regulated parameters may be convenient toxicity parameters. The present study indicates that delta mu Na+ across the adductor muscle membrane of Mytilus edulis is a regulated parameter, and that injuries develop whenever this parameter drops below -700 J/mole. 2. Regulatory physiological parameters may display quick and substantial changes when regulatory mechanisms are activated to counteract variations in the regulated parameters. Thus, regulatory parameters may be used as sensitive alarm parameters in environmental monitoring. The present results indicate that the phosphate index [(ATP x P-arginine)/(Pi)2], metabolic rate and strombine may be used as alarm parameters. 3. The combined response of all parameters may provide a pollutant-specific fingerprint in environmental monitoring.     

The use of RAPD markers for the detection of gene introgression in potato

Randomly Amplified Polymorphic DNAs were employed to demonstrate that potato dihaploids generated after interspecific pollination of a tetraploid Solanum tuberosum cultivar (Pentland Crown) by Solanum phureja dihaploid inducer clones could not be of parthenogenetic origin. Of six different 10-mer oligonucleotides, four generated products from total potato dihaploid genomic DNAs which were not derived from the S. tuberosum parent. Gel electrophoresis and Southern analysis indicated that these amplified bands originated from S. phureja. The results are discussed in the context of recent cytological and molecular evidence which demonstrates that potato dihaploids are aneusomatic (Clulow et al. 1991) and emphasises this approach as a general methodology for the detection of alien gene introgression in both natural and cultivated plant populations.     

Role of physiological energetics in ecotoxicology

• 1.1. The role of physiological energetic measurements combined with chemical analyses of contaminants in body tissues of mussels in fundamental toxicological studies and pollution monitoring programmes is outlined.
• 2.2. Important features of this toxicological approach are briefly reviewed, including aspects of bioaccumulation, sensitivity, quantitative concentration-response relationships, QSARs, mechanistic interpretation, ecological relevance, integration of the consequences of multiple mechanisms of toxicity and effects of contaminant mixtures and application to laboratory and field studies.
• 3.3. This review focuses particularly on recent advances in understanding and predicting the effects of complex mixtures of contaminants.

     

不同经济类型高粱的RAPD分析

对四种不同经济类型高粱采用ＤＮＡ随机扩增多态技术（ＲＡＰＤ）进行了比较研究。１８种引物扩增后共得到５４个ＲＡＰＤ标记,其中２３个标记在进行４种高粱成对比较时呈多态。根据计算出的遗传距离值可以发现虽然不同种高粱之间差异虽然较小,但仍具有丰富的遗传多样性。     

The use of RAPD genomic fingerprinting to study relatedness in strains of Acidithiobacillus ferrooxidans

Twelve strains of Acidithiobacillus ferrooxidans were recovered from acid mine drainage (AMD) sites from three different geographical locations: Copper Cliff, Ontario, Canada; Mineral City, OH, USA; and Cornwall, England. The spread-plate technique and various culture media were used to isolate and purify all strains. DNA was extracted from each purified culture and amplified using PCR and twenty, 10-mer primers. Amplification products were separated by gel electrophoresis and photographed under UV light. The RAPD (Randomly Amplified Polymorphic DNA) profiles were compared on the basis of the presence or absence of each DNA band and a data matrix was constructed. Strain diversity was calculated using the Jaccard's coefficient and UPGMA (Unweighted Pair-Group Arithmetic Average Clustering) cluster analysis. The variations in the banding patterns indicated genomic variability among the twelve A. ferrooxidans strains tested. The primers used in this study grouped the twelve strains into five major groups. Similarities between the strains ranged from 5.49% to 85.14%. These results show that the strains have a high degree of genomic diversity and that the RAPD procedure is a powerful technique to assess strain variability in this bacterium.     

Workshop on rotifers in ecotoxicology

The aim of the workshop on rotifers in ecotoxicology was to stimulate discussions on new developments in the field. Discussions about the use of biomolecular tools indicate that gene expression analysis with rotifers should be available in the next few years. Such analyses will be a great asset as they enable ecotoxicologists to study molecular mechanisms of toxicity. Rotifers also appear as useful tools in the risk assessment of pharmaceuticals and their metabolites that find their way into aquatic ecosystems because their sensitivity to some of these substances is higher than that of cladocerans and algae. The nature and extent of the impact of potential endocrine disruptors on aquatic invertebrates is another poorly resolved issue for which rotifers are a promising tool. Indeed, rotifers seem to be particularly sensitive to androgenic and anti-antiandrogenic substances, whereas copepods and cladocerans are typically more affected by estrogens and juvenile hormone-like compounds. Besides their usefulness in these emerging fields of aquatic ecotoxicology, it was emphasized that research with rotifers on basic issues like, e.g., toxicant interference with predation, competition, or interspecific and interclonal variation in ecotoxicological tests is still needed. Guest editors: S. S. S. Sarma, R. D. Gulati, R. L. Wallace, S. Nandini, H. J. Dumont & R. Rico-Martínez Advances in Rotifer Research     

Rotifers in ecotoxicology: a review

In the past five years the use of rotifers in ecotoxicologial studies has substantially increased. This greater interest has been due to the central role of rotifers in freshwater planktonic communities, the ease and speed of making quantitative measurements of mortality and reproduction, their sensitivity to common pollutants, the commercial availability of cysts, and the existence of reliable, standardized protocols. The main endpoints used in ecotoxicology studies are reviewed, including mortality, reproduction, behavior, cellular biomarkers, mesocosms, and species diversity in natural populations. For each endpoint, published studies are cited, along with the compounds investigated, duration of exposure, and the LC50s, EC50s or NOECs reported. Rotifers have been included as part of a standardized mesocosm and in several large-scale, outdoor mesocosm studies. A critique of rotifer use in ecotoxicology is offered and it is concluded that the scientific basis for including rotifers as part of a battery of ecotoxicological tests is well established.