Discrimination of three Typhlodromalus species (Acari: Phytoseiidae) using random amplified polymorphic DNA markers

We compared the random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) banding patterns obtained from four laboratory cultures representing three phytoseiid mite species (Typhlodromalus limonicus (Garman and McGregor), two cultures of Typhlodromalus manihoti (de Moraes) and Typhlodromalus tenuiscutus (McMurtry and de Moraes). The RAPD-PCR was conducted on the pooled DNA from five adult female mites. For each culture, three samples of five females were analysed with each of eight RAPD-PCR primers. Five of the eight primers could be used individually to distinguish the species. To quantify the within- and between-species variation, genetic distances were calculated based on the proportion of shared scorable bands. The within-species genetic distances (0.072-0.186) were much lower than the between-species genetic distances (0.407-0.656). We believe that this technique could be used effectively to identify other cryptic mite species.     

Lake Tana large barbs: phenetics, growth and diversification

Among the Lake Tana large barbs of about 10 cm SL only representatives of the' acute'morphotype can be distinguished, in the size range 10–20 cm SL' bigmouth big eye' can be identified also. As for the rest, very few individuals can be confidently affiliated with a particular morphotype most of them looking like' intermedius'. Even within the range of 20–30 cm SL some individuals are still difficult to identify. Principal component analysis of cranial characters revealed discrete groups of morphotypes. Differences in both external and cranial characters of the morphotypes result from divergence which is most pronounced when fish are 4–5 years old and 20–25 cm SL. This divergence cannot be related exclusively with differences in the growth rates of individuals representing different morphotypes. Differences in food composition between the morphotypes probably increase in parallel with their morphological divergence. Differences between the morphotypes in the lateral line (11) and the gill rakers (Sb) counts were revealed using ANOVA. Comparison of the Lake Tana Barbus complex of forms with that previously known from Lake Lanao (Philippines) suggests that in both lakes the different forms arose sympatrically but that sympatric speciation in Lake Lanao has advanced further than in Lake Tana.     

Fast discrimination (RAPD-PCR) of the species forming the pest complex Aleurodicus dispersus–Lecanoideus floccissimus (Hom: Aleyrodidae)

Abstract:  The Aleurodicus dispersus–Lecanoideus floccissimus complex has become a very important agricultural pest in the Canaries. These species are not easily differentiated by their morphological characteristics. The aim of the present study was to obtain genetic markers to unambiguously distinguish both species of this complex. Thus, six random primers were employed to generate RAPD markers. Different RAPD profiles were observed for the different species. The analysis successfully identified 39 reproducible and specific markers for L. floccissimus and 51 for A. dispersus , i.e. bands present in all individuals of one species but never in the other. RAPD markers resulted a useful tool for discriminate both species. Early identification of species and also of biotypes is crucial when designing control strategies to avoid the spread of the pest and consequently the considerable economic losses it causes in tropical crops.     

FISH SPECIES IN STEIUTONTEIN DAN,TUGELA-VAAI SYSTEM,SOUTH AFRICA

SUMMARY

Two alien species and seven indigenous species, including two minnow species, were present in Sterkfontein Dam. Of the larger species, Barbus aeneus and Labco capensis were the dominant in terms of numbers.     

A behavioural study of hybridization between Barbus barbus and Barbus meridionalis

The reproductive behaviour of two species of barbel ( Barbus barbus and Barbus meridionalis ) was investigated by means of aquarium experiments in several matings of six combinations. The reproductive behaviour of the two species appears to be similar and hybridizations were observed, showing that no complete behavioural barrier blocks the mating of the two species.     

A review of random amplified polymorphic DNA (RAPD) markers in fish research

During the last 15 years, molecular markers have entered the scene of genetic improvement in different fields of agricultural research. The ease and simplicity of RAPD (randomly amplified polymorphic DNA) techniques make it ideal for genetic mapping, plant and animal breeding programs, and DNA fingerprinting, with particular utility in the field of population genetics. This review summarizes the use of RAPD markers in fish research. The advantages and disadvantages of the RAPD approach will be discussed.     

白地霉遗传多样性与生态地理起源地的相关性分析

采用随机扩增多态性DNA(RAPD)分子标记方法从22个随机引物中筛选出TubeB-03、TubeB-07、TubeB-12三个最佳引物分析来源于7个省区的23株白地霉的种内遗传多样性,并用UPGMA聚类分析法评价它们之间的亲缘关系.结果表明,不同来源地的白地霉通过RAPD分析显示出较高的遗传差异性,并且,在系统进化树上处于同一分枝的菌株来源于生态地理相近的区域,仅有个别例外.因此,应用RAPD分子标记技术对来自不同生态区的白地霉种内遗传多样性和亲缘关系进行分析是可行的.     

Identification of Toxigenic Fusarium Species using PCR Assays

Isolates of the toxigenic cereal pathogens Fusarium culmorum, Fusarium graminearum, Fusarium crookwellense and Fusarium avenaceum, from Poland (48 isolates) and 12 from England, New Zealand, Italy and Canada, were examined using random amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR), sequence-characterized amplified regions (SCARs), morphology and mycotoxin production under laboratory conditions. Their DNA products were compared by RAPD-PCR, which showed species-specific bands and the greatest diversity among isolates of F. avenaceum. PCR using three 20-mer-primer-pairs that are reported to be useful for identification of F. culmorum and F. graminearum group 2 confirmed their species-specificity. The same species-specific PCR product was observed in isolates of both nivalenol and deoxynivalenol chemotypes of F. culmorum or F. graminearum. A clear relationship was found between morphological and species-specific PCR identification of F. culmorum and F. graminearum isolates. However, F. avenaceum can be confused when using primers FA-ITS F/R (SCAR 2-14) with Fusarium tricinctum because the same band 272 bp appears in the gel, in both species probes.     

Anthropogenic changes in the freshwater fish fauna of Italy, with reference to the central region and Barbus graellsii, a newly established alien species of Iberian origin

In a survey of the west-central Italian rivers Ombrone, Fiora, Albegna and Bruna, among established exotic species, the Iberian barbel Barbus graellsti was recorded in Italian fresh waters for the first time. Morphological identification was supported by comparison of cytochrome b sequences with those from related barbel species. Other exotics of particular note were Barbus barbus, Pseudorasbora parva and Leuciscus cephalus , together with the Padano-Venetian Chondrostoma genei and Padogobius bonelli. Native species still present included Leuciscus lucumonis, Telestes muticellus, Rutilus rubilio and Padogobius nigricans , but were now more restricted to upper reaches and smaller watercourses. The deleterious effect of alien species on native forms is discussed with particular reference to probable competition between C. genei and L. lucumonis , and between the two gobies. The checklist of species introduced to the fresh waters of Italy is now updated to 34. For the Italian freshwater fish fauna in general, the conservation status of three native species ( Acipenser naccari, Salmo marmoratus and Knipowitschia punctatissima ) has been improved but five species are believed to be at risk ( Salmo carpio, L. lucumonis, Scardinius scardafa, Gobio benacensis and P. nigricans ) and four anadromous species ( Petromyzon marinus, Lampetra fluviatilis, Acipenser sturio and Huso huso ) no longer breed in Italian fresh waters. The processes of change in the composition of the Italian freshwater fish fauna as a whole may be summarized as successively 'padanization', 'danubization' and now 'globalization'.     

Influence of the daily distribution of light on reproduction in the barbel, Barbus barbus (L.)

The influence of the daily distribution of light on the duration of the breeding season of the barbel was investigated. Interrupted night photoperiods (6L:2D:2L:14D or 6L:8.5D:2L:7.5D) allowed spawnings of male and female barbel (previously maintained under 10L:14D or 16.5L:7.5D) to continue, whereas a 2 or 8.5 h shorter photoperiod (8L: 16D) inhibited both sexes. The number of spawnings for each female was significantly higher under 6L:2D:2L:14D or 6L:8.5D:2L:7.5D (respectively 2.9 and 3.6 spawnings on average) than in control groups maintained under 8L:16D (0.6 and 2.1 spawnings on average). These results suggest that there is a daily rhythm of photosensitivity in the barbel.     

猕猴桃模板DNA的提取及RAPD-PCR最佳反应体系的建立

以改良CTAB法从猕猴桃叶片中制备模板DNA ,优化了PCR热循环参数 ,建立了RAPD PCR扩增的最佳反应体系。实验结果表明 ,CTAB提取液中EDTA组分的浓度对模板提取影响很大 ,其最适浓度为 80mmol/L ;用异丙醇沉淀后不经乙醇洗涤纯化的DNA不会影响扩增效果。PCR热循环参数为 :94℃预变性 5min ;94℃变性 1min ,37℃退火 1min ,72℃延伸 2min ,循环 4 0次 ;最后在 72℃延伸 6min。     

Keys to the blow flies of Taiwan,with a checklist of recorded species and the description of a new species of Paradichosia Senior-White (Diptera,Calliphoridae)

Blow flies (Diptera: Calliphoridae) show a great diversity in behavior and ecology, play important roles in ecosystems, and have medical and forensic importance to humans. Despite this, the taxonomy and classification of Taiwan''s Calliphoridae have rarely been studied. In this study, specimens of Taiwanese calliphorids were collected and carefully studied, and all 76 species recorded in Taiwan are listed following the identification keys. Dichotomous keys to all subfamilies, tribes, genera, and species of blow flies recorded in Taiwan are provided, including 16 species that are newly recorded from Taiwan. In addition, one new species of the genus Paradichosia Senior-White is described and illustrated. We also discuss the morphological differences between the specimens of Silbomyia hoeneana Enderlein collected from China and Taiwan, a species that has only been found previously in Southern China.     

Early development of the cephalic skeleton of Barbus barbus (Teleostei, Cyprinidae)

The inception, and development of the cephalic skeleton of Barbus barbus from hatching to 24 days passes through periods of fast and slow growth; these rates are not the same in different parts of the skull. Trabeculae, parachordal plates, Meckelian cartilages and hyposymplectics are present at hatching. Then the cartilaginous floor of the neurocranium develops, the pars quadrata, the hyoid bars and branchial arches elements appear shortly before the first movable dermal bones, the dentaries, maxillae and opercles. The first bone of the braincase to appear is the parasphenoid; other bones develop subsequently and at the same time: the angular, quadrate, interopercle and fifth ceratobranchial. Later the splanchnocranium continues to develop at a relatively fast rate while the neurocranium shows little growth. The braincase does not begin to close before the 24th day, nor do the first bones of the skull roof appear, while the bucco-pharyngeal apparatus is complete, having the adult shape. The early constitution of the latter structures seems to be linked with the mechanical demands of biological functions such as breathing and feeding.