Comparison of mtDNA extracting methods for common sarcosaphagous insects / 法医学杂志

OBJECTIVE@#To compare effects of three different methods for mtDNA extraction from common sarcosaphagous insects including cetyl trimethyl ammonium bromide (CTAB) method, sodium dodecyl sulfate-potassium acetate (SDS-KAc) method and sodium dodecyl sulfate-proteinase K (SDS-PK) method.@*METHODS@#Seventy-two insects from four species [Chrysomya megacephala (Fabricius, 1784), Eusilpha bicolor (Fairmaire, 1896), Paraeutrichopus pecoudi (Mateu, 1954), Vespa velutina (Lepeletier, 1836)] were collected from the corpses of the rabbits in Changsha district. The total DNA of above samples was extracted by CTAB, SDS-Kac and SDS-PK methods. The purity and concentration of DNA were examined by protein-nucleic acid spectrophotometry, and mtDNA were amplified by specific primers and PCR products were detected by agarose gel electrophoresis. Then PCR products were sequenced and subsequently up-loaded to GenBank.@*RESULTS@#mtDNA was successfully extracted with three methods from most of the samples. The SDS-PK method was better in DNA purity compared to other methods and the CTAB method was superior in extracting DNA from old samples, while SDS-KAc method showed no significant difference for extraction effects of different samples.@*CONCLUSION@#The most appropriate method should be chosen depending on different situations. SDS-PK method is expected to obtain high-quality DNA, while CTAB method is preferred in extracting obsolete samples. SDS-KAc method is low cost and can be used in various kinds of preliminary experiments.

Comparison of mtDNA extraction from different parts of sarcosaphagous insects / 法医学杂志

OBJECTIVE@#To explore mitochondrial DNA (mtDNA) extraction effects of different parts from sarcosaphagous insects using improved cetyltriethylammnonium bromide (CTAB) method.@*METHODS@#Thirteen Lucilia sericata (Meigen) and 13 Nicrophorus fossor (Erichson) were collected from the corpses of rabbits placed on the outdoor lawn in Huhehot district. Four parts (head, chest muscle, legs and wings) of insect were collected, and the mtDNA of all samples were extracted using CTAB method. The purity and concentration were tested using protein and nucleic acid spectrophotometry. The integrity of the extracted mtDNA and PCR products were checked by agarose gel electrophoresis. The PCR products were sequenced and the obtained sequences were imputed into GenBank for comparison.@*RESULTS@#mtDNA were successfully extracted from 10 head samples, 6 legs samples, 4 wing samples and 13 chest muscle samples of the Lucilia sericata (Meigen). Also, mtDNA were successfully extracted from 5 head samples, 8 legs samples, 3 wing samples and 13 chest muscle samples of the Nicrophorus fossor (Erichson).@*CONCLUSION@#mtDNA can be obtained from chest muscle and other parts of sarcosaphagous insects using the improved CTAB method.

Extraction of high-quality host DNA from feces and regurgitated seeds: a useful tool for vertebrate ecological studies

DNA extraction methods for genotyping non-invasive samples have led to great advances in molecular research for ecological studies, and have been particularly useful for analyzing threatened species. However, scarce amounts of fragmented DNA and the presence of Taq polymerase inhibitors in non-invasive samples are potential problems for subsequent PCR amplifications. In this study we describe a novel technique for extracting DNA from alimentary tract cells found on external surfaces of feces and regurgitated seeds. The presence of contaminants and inhibitors is minimized and samples are preserved intact for use in other ecological research (e.g. trophic studies). The amplification efficiency and purity of the extracted DNA from feces were significantly higher than in commonly used extraction procedures. Moreover, DNA of two bird species was identified from seeds expelled by regurgitation. Therefore, this method may be suitable for future ecological studies of birds, and other vertebrate groups.

DNA extraction from bristles and quills of Chaetomys subspinosus (Rodentia: Erethizontidae) using a novel protocol

DNA extraction protocols are as varied as DNA sources. When it comes to endangered species, it is especially important to pay attention to all details that ensure the completion of the study goals and effectiveness in attaining useful data for conservation. Chaetomys subspinosus (Rodentia: Erethizontidae) is a secretive arboreal porcupine endemic to certain ecosystems of the Brazilian Atlantic Forest. A multidisciplinary study (including genetic data) was performed to create a management plan for the conservation of this species. Individuals from natural populations of the states of Bahia, Espírito Santo and Sergipe were sampled. To obtain a reliable and abundant amount of starting material, non-destructive methods were tested, extracting DNA from the bristles and quills that comprise most of this animal’s hide. This method has also been innovative in adapting a DNA extraction protocol traditionally used for plants. Digestion using proteinase K was followed by protein precipitation with CTAB, a chloroform-isoamyl alcohol cleaning and DNA precipitation with isopropyl alcohol. This protocol supplies good-quality DNA for genetic analysis with molecular markers based on PCR.

Evaluation of a method for high yield purification of largely intact mitochondrial DNA from human placentae

We developed, and quantitatively and qualitatively evaluated an easily reproducible method for high yield purification of mitochondrial DNA (mtDNA) from human placentae by mechanical tissue disruption, differential centrifugation of mitochondria, enzymatic digestion, phenol extraction and ethanol precipitation. Average mtDNA yields were 2.5 microg/g tissue (without an RNAse treatment step) and 1.5 microg/g tissue (with an RNAse treatment step). This mtDNA migrated as a 16.5-kb isolated band in agarose gels; it yielded fragments of expected sizes after digestion with restriction enzymes; it successfully served as a template in long PCR for amplification of mtDNA sequences, and hybridized to an mtDNA probe in a predictable fashion. MtDNA yields of this method were 10-fold higher than those of previously reported ones for mtDNA purification from freshly obtained human cells and tissues, with the advantage that more placental tissue can be obtained for mtDNA purification than other types of tissue, at lower cost, and with minimal or no ethical issues

Characterization of six rat strains (Rattus norvegicus) by mitochondrial DNA restriction fragment length polymorphism

Restriction fragment length polymorphism (RFLP) was used to examine the extent of mtDNA polymorphism among six strains of rats (Rattus norvegicus) - Wistar, Wistar Munich, Brown Norway, Wistar Kyoto, SHR and SHR-SP. A survey of 26 restriction enzymes has revealed a low level of genetic divergence among strains. The sites of cleavage by EcoRI, NcoI and XmnI were shown to be polymorphic. The use of these three enzymes allows the 6 strains to be classified into 4 haplotypes and identifies specific markers for each one. The percentage of sequence divergence among all pairs of haplotypes ranged from 0.035 to 0.33 percent, which is the result of a severe population constriction undergone by the strains. These haplotypes are easily demonstrable and therefore RFLP analysis can be employed for genetic monitoring of rats within animal facilities or among different laboratories

Restriction enzyme fragment patterns of mtDNA from a galactose oxidase-producing mold

1. Mitochondrial DNAs from Dactylium dendroides, Hypomyces rosellus, Fusarium graminearum, Gibberella fujikuroi, Fusarium tricinctum strains and a galactose oxidase (GAO)-producing mold (original strain) presented distinctive restriction enzyme fragment patterns with the endonucleases Hind III and EcoRI. 2. A small number of comigrating bands was found when the GAO-producing mold was compared with the others. The molecular size of mtDNA from the GAO-producing mold, as judged by summation of fragment sizes produced by digestion with EcoRI, Hind III and Bgl II, is 61.3 +/- 2.16 kb. 3. The results suggest that the mtDNA from the GAO-producing mold strain is distinct from that of D. dendroides and all other ascomycetes analyzed