Identification of schistosome hybrids and larval parasites using rRNA probes

Observations have been made on the ribosomal RNA (rRNA) gene units of hybrid progeny produced by experimental crosses of S. haematobium × S. mattheei, S. mattheei × S. bovis and S. haematobium × S. intercalatum. Hybridisation of DNA probe pSM 889 to restriction endonuclease digested DNA extracted from adult worms showed that each parental form could be differentiated by differences in the rRNA gene unit. In each experimental cross the F1 hybrid generation produced a composite major banding pattern of the two parental species. No differences associated with the stage of development were detected in the major bands of hybridisation when DNA extracted from various life-cycle stages of S. mansoni and S. margrebowiei was digested with EcoR1 and hybridised with probe pSM 889. Prepatent infections of S. mansoni in Biomphalaria glabrata were detected 16 days post-infection utilising probe pSM 389 and dot blot analysis. Small numbers of intact cercariae dotted onto nitrocellulose were detected using probe pSM 389, 10 cercariae being the minimum number required for accurate determination.     

Restriction fragment length polymorphism of the major histocompatibility complex of the dog

Human major histocompatibility complex (HLA) cDNA probes were used to analyze the restriction fragment length polymorphism (RFLP) of the DLA-D region in dogs. Genomic DNA from peripheral blood leucocytes of 23 unrelated DLA-D-homozygous dogs representing nine DLA-D types (defined by mixed leucocyte reaction) was digested with restriction enzymes (Bam HI, Eco RI, Hind III, Pvu II, Taq I, Rsa I, Msp I, Pst I, and Bgl II), separated by agarose gel electrophoresis, and transferred onto Biotrace membrane. The Southern blots were successively hybridized with radiolabeled HLA cDNA probes corresponding to DR, DQ, DP, and DO beta genes. The autoradiograms for all nine enzyme digests displayed multiple bands with the DRb, DQb, and DPb probes while the DOb probe hybridized with one to two bands. The RFLP patterns were highly polymorphic but consistent within each DLA-D type. Standard RFLP patterns were established for nine DLA-D types which could be discriminated from each other by using two enzymes (Rsa I and Pst I) and the HLA-DPb probe. Cluster analysis of the polymorphic restriction fragments detected by the DRb probe revealed four closely related supertypic groups or DLA-DR families: Dw3+Dw4+D1, Dw8+D10, D7+D16+D9, and Dw1. This study provides the basis for DLA-D genotyping at a population level by RFLP analysis. These results also suggest that the genetic organization of the DLA-D region may closely resemble that of the HLA complex.     

ALLOZYME COMPARISONS AMONG SPECIES OF THE BULINUS FORSKALII GROUP (GASTROPODA: PLANORBIDAE) IN CAMEROON

Allozyme comparisons were made for adult Bulinus forskalii,B. camerunensis, and B. senegalensis from populations in Cameroonusing starch gel electrophoresis. Fifteen loci were examinedbut no differences were found between B. forskalii and B. camerunensis,bringing into question the validity of B. camerunensis as aseparate species. Bulinus senegalensis differed from B. forskaliiand B. camerunensis in allozymes for acid phosphatase, alpha-glycero-phosphatedehydxogenase, hydroxybutyrate dehy-drogenase, and phosphoglucomutase.No differences were found, as reported elsewhere, between B.forskalii and B. senegalensis for aspartate amino-transferase,isocitrate debydrogenase, phosphogluco-isomerase, and xanthineoxidise. No polymorphism was seen in B. camerunensis or variousB. senegalensis populations examined. Three alleles for isocitratedehydrogenase were observed for B. forskalii. Mixed populationsof B. forskalii and B. senegalensis were found at four sitesbut no evidence of hybridization between these species was found. (Received 9 May 1988; accepted 30 August 1988)     

Screening of plasmids in non-pathogenic corynebacteria

Abstract A screening of plasmids in 25 nonpathogenic coryneform bacteria was carried out. 11 Strains showed at least one plasmid, ranging in size from 4.2 to 55 kb. These plasmids did not encode bacteriocin production or resistance to a number of antibiotics or to ions such as arsenite, mercury(II) and cobalt(II). A detailed study of plasmid pBL100 from Brevibacterium linens is presented. pBL100 has a size of 7.75 kb, and contains single sites for the endonucleases: Hin dIII; Pst I, Bgl II, Eco RI and Bam HI. B. linens is easily and efficiently transformed with vectors derived from pBL1 isolated from Brevibacterium lactofermentum .     

丝裂霉素C和二甲基亚砜对家蚕核型多角体病毒(BmNPV)的诱变

该文报道强诱变剂丝裂霉素C(MMC)和化学溶剂二甲基亚砜(DMSO)在家蚕蛹体内对家蚕核型多角体病毒(BmNPV)的诱变结果。MMC对BmNPV具有诱变效应： (1)导致蚕蛹发病时间延迟,发病死亡率下降,有显著的剂量效应;(2)部分病蛹体内发生异常形态多角体,继代试验证实具有遗传稳定性。其中具对角线裂痕的四角形超大多角体(15.0-30.0, um)尚属首次发 现;(3)诱变的BmNPV多角体内部结构发生变化;(4)诱变的BmNPV-DNA经EcoRI、Bgl II和 Bam HI酶切消化,其电泳图谱出现某些DNA泳带的增加或丢失。以上结果说明,MMC可能诱导BmNPV基因组发生了多处位点的突变。DMSO处理剂量在9.0 μL/蛹及其以下各剂量组,对BmNPV无诱变效应。     

Comparative restriction analysis of chromosomal DNA of strains of Photobacterium leiognathi

Chromosomal DNA in 5 hereditary variants occurring in Photobacterium leiognathi population was subjected to restriction analysis. The variants differed in the levels and regulation of luminescence and colony morphology. Agarose electrophoresis of DNA fragments isolated after exposure to Hind II, Bam HI, Bgl I and Pst I restriction endonucleases revealed respectively 38, 28, 35 and 29 fragments equally distributed by their molecular weights. Electrophoregrams of the 5 strains were absolutely identical. After exposure of DNA of all the strains to PVu II, Xho II, Sal GI and Eco RI restriction endonucleases there were detected no fragments. The pleoiotropic genetic variation in these strains was not associated with large deletions or amplification of chromosomal DNA regions.     

转甲状腺素蛋白基因在酵母中的表达

用限制酶BamHI将含人TTR基因的DNA片段(约493bp)从质粒 pSK-TTR上切下后并插入到分泌型载体pHIL-SI的BamHI位点上,经酶切鉴定重组质粒pHIL-SI-TTR上的TTR基因插入方向正确。将pHIL-SI-TTRDNA用BglII酶切后,转入真核表达系统——毕赤氏酵母。得到的转化子经摇瓶发酵,上清液用15%SDSPAGE检测,有TTRF的表达。经DEAESepheroseF.F离子交换柱和SephacrylS200分子筛层析,得到纯化的TTRF。体外实验表明TTRF对肝癌细胞有抑制作用。     

Variation of plastid and mitochondrial DNAs in the genus Hedysarum

Summary Plastid and mitochondrial DNAs from Hedysarum species of the western Mediterranean basin, H. spinosissimum ssp eu-spinosissimum, H. spinosissimum ssp capitatum, H. carnosum, H. coronarium and H. flexuosum, were compared by restriction endonuclease fragment analysis. ctDNA fragment patterns for ssp eu-spinosissimum and ssp capitatum were indistinguishable in different enzyme digests. An identical ctDNA variation was found in Hpa II digests with two Sardinian populations of ssp capitatum. Each of the two subspecies was characterized by specific mt DNA patterns with Pst I, Bam HI, Sma I and EcoRI. No variation was detected in populations of different geographical origins for a given subspecies. H. carnosum, H. coronarium and H. flexuosum generated specific ct and mt DNA patterns. Comparison of mitochondrial fragments indicated: — a strong homology between the two subspecies, — a closer homology among the three other diploids, each being closer to the other two than to H. spinosissimum subspecies — as was also the case for the plastid genomes.     

The number of ribosomal RNA genes in Thermus thermophilus HB8.

We have examined the number of rRNA genes in Thermus thermophilus HB8 by hybridization of Bam HI -, Hind III - and Pst I - digests of DNA to 3'- (3 2p) 23S, 16S and 5S rRNAs according to the Southern procedure. The restriction gels gave two radioactive bands with 23S and 5S rRNA. Furthermore, band positions were indistinguishable from one another when 23S and 5S rRNAs were used as probes to Bam HI and Hind III digests, indicating that each band contains sequences corresponding to the 3'-end of 23S and 5S rRNAs. The Pst I digest also gave two radioactive bands with 23S and 5S rRNAs as probes, where one band position was identical, but the other different. The 16S rRNA did hybridize with two fragments, using a Bam HI, as well as a Bam HI - Hind III double digest. The Hind III digest gave one band using 16S rRNA as a probe. It is concluded that the Thermus thermophilus HB8 chromosome carries at least two sets of genes for 23S, 16S and 5S rRNAs.     

Restriction analysis of the plasmid and chromosomal DNA of the strain Streptomyces fradiae--a producer of neomycin

Plasmid DNA with a molecular weight of 53-55 Md was isolated from Streptomyces fradiae strain 676 producing neomycin on centrifugation of the DNA preparation at the density gradient of cesium chloride-ethidium bromide. The extrachromosomal DNA had 6 recognition sites for Bgl II, more than 13 recognition sites for Bam HI, more than 14 recognition sites for Kpn I, more than 18 recognition sites for Pst I, more than 20 recognition sites for Sac I, more than 21 recognition sites for Pvu II and no recognition sites for Eco RI, Eco RV, Hind III and Sla I.     

Polymorphic microsatellites in the African freshwater snail,Bulinus forskalii (Gastropoda,Pulmonata)

Eleven microsatellites were isolated in the freshwater snail Bulinus forskalii, intermediate host for the medically important trematode Schistosoma intercalatum. Characterization in 60 snails from three populations of B. forskalii from Cameroon revealed 4 to 18 alleles per locus. Low observed heterozygosity but higher expected heterozygosity, high F_IS estimates, significant departures from Hardy–Weinberg equilibrium and genotypic linkage disequilibria all indicate that B. forskalii is a preferential selfer. High F_ST estimates suggest that effective dispersal is limited and genetic drift is an important determinant of genetic structure. The potential utility of the microsatellite primers in other closely related Bulinus species was explored.     

大熊猫线粒体DNA的九种限制酶图谱

本文用9种限制性内切酶（BamHⅠ,BglⅠ,BglⅡ,EcoRⅠ,EcoRⅤ,PstⅠ,PvuⅡ,SalⅠ,XhoⅠ）分析大熊猫的线粒体DNA（mtDNA）。构建其中5种酶（BamHⅠ,EcoRⅠ,EcoRⅤ,PstⅠ,PvuⅡ）的mtDNA物理图谱。大熊猫mtDNA的分子大小约为16.4 Kb,酶切位点是随机分布。我们的结果为进一步研究大熊猫mtDNA进化提供了基础资料。     

The use of fractionation in a polyethylene glycol-dextran two-phase system for the testing and purification of restriction endonucleases

A simple procedure was developed for testing and purification of restriction endonucleases Msp I, Pst I, Bam HI, Pvu I, Pvu II that includes biomass destruction, fractionation of cell-free extracts in the aqueous two-phase (polyethylene glycol-dextran) system and chromatography oh phosphocellulose. Optimal conditions for the fractionation of Msp I, Pst I, Bam HI, Pvu II, EcoR I, EcoR II, BspR I, Alu I were chosen. For separation of Pvu I and Pvu II gel filtration through biogel A-0.5 m was additionally introduced.     

Freshwater snails of São Tomé, with special reference to Bulinus forskalii (Ehrenberg), host of Schistosoma intercalatum

São Tomé Island has 3 known taxa of freshwater gastropod, here identified to species for the first time; Neritina afra Sowerby, Ferrissia eburnensis Binder and a distinctive form of Bulinus forskalii (Ehrenberg). The Bulinus acts as intermediate host for the parasite Schistosoma intercalatum Fisher, the cause of human schistosomiasis in foci of infection detected in recent years on São Tomé. A morphological characterization of this snail is presented, in respect of the shell, radula and copulatory organ. It is compared with B. forskalii populations sampled on the African mainland (Nigeria, Cameroon, Gabon and Angola) and with related taxa. Despite differences in the shell from the commonly found form of B. forskalii it seems appropriate to identify the São Tomé population as an extreme conchological variant of this taxon.     

Restriction fragment length polymorphism analysis of major histocompatibility complex class II genes from inbred chicken lines

High molecular weight DNA was extracted from sperm from chickens of 14 inbred lines. The DNA was digested with each of four restriction enzymes (Pvu II, Hind III, Bgl II, and Bam HI), electrophoresed for 18 or 45 h, blotted onto nitrocellulose, and hybridized to a chicken major histocompatibility complex (MHC, B complex) class II beta-chain probe (beta 2-exon specific). Restriction fragment length polymorphisms (RFLPs) were found with each of the restriction enzymes used. Birds with the same B haplotype always showed the same RFLP pattern; however, some birds of different B haplotypes also shared the same RFLP pattern. To test for the Mendelian inheritance of the RFLP patterns, the F2 progeny of an informative cross were analysed. The RFLP patterns corresponded with the serologically determined B haplotypes of the F2 birds, thereby showing the Mendelian inheritance of the polymorphic bands.     

HLA-DR4-associated haplotypes are genotypically diverse within HLA

Biochemical diversity among products of class II HLA genes has been observed in individuals who appear to be HLA-D and DR-identical by cellular and serologic typing. We used techniques of restriction enzyme fragment analysis by Southern blotting to analyze this diversity at the level of cellular DNA. A panel of 17 HLA-DR4 homozygous cell lines (HCL) were investigated by using cDNA probes homologous to DQ beta, DQ alpha, and DR beta genes. Each probe was hybridized to cellular DNA digested with a series of different restriction endonucleases. Polymorphisms were observed with the use of the enzymes Pst I, Hind III, and Bam HI: Hybridization of cellular DNA digested with Hind III and Pst I with the DQ beta probe revealed specific polymorphisms, as did hybridization of the Pst I digest with the DQ alpha cDNA probe and the Bam HI digest with the DR beta probe. The observed differences fall into two categories: first, considerable diversity was seen between HLA-DR4 HCL that represent different HLA-D-defined haplotypes; second, diversity was also observed among HCL of the same DR4-associated HLA-D cluster. In contrast to the DQ cDNA probes, hybridization with the DR beta probe revealed relatively limited polymorphism by using a panel of different restriction endonucleases. Thus, although there is a general pattern of polymorphic restriction enzyme fragments homologous to DQ probes within an HLA-D cluster, the pattern seen for any particular cell line was not sufficiently distinct to assign an HLA-D or DR specificity.     

Altered restriction patterns of microwave irradiated lambdaphage DNA.

Samples of lambdaphage DNA exposed to short pulses of microwave irradiation were subjected to restriction fragmentation by Eco RI and Bam HI. Eco RI digests of microwaved DNA samples yielded three additional fragments ranging in base pair lengths between 24,226 and 7,421 besides the six expected fragments. While Bam HI digests of the microwaved samples did not yield any additional fragments, mobilities of the Bam HI fragments from the microwaved DNA samples were slower and the bands were broader in comparison to those from native samples. We attribute these altered restriction patterns to the conformational anomolies in DNA resulting from single strand breaks and localized strand separations induced by microwave irradiation.     

Fragment comparison of hamster mitochondrial DNA: general conclusions about the evolution of mitochondrial DNA

Mitochondrial DNA from heart, liver and kidney of two hamster species, Mesocricetus auratus and Cricetulus griseus has been digested with the restriction endonucleases Bam HI, Bgl I, Eco RI, Hae III, Hind III, Hpa II and Xba I. Cleavage patterns for Hpa II are identical for both species, while only two of seven bands are common with Hae III. All other endonucleases give a species-specific cleavage pattern. The results suggest a fairly high phylogenetic differentiation of the mitochondrial genome between the two hamster species. The large differences in mitochondrial DNA variability between different species is discussed as a function of mutation rate and species-specific generation time.     

OBSERVATIONS ON THE POPULATION DYNAMICS OF SNAIL HOSTS FOR SCHISTOSOMES IN THE DELTA OF THE SENEGAL RIVER BASIN

Between 1987 and 1990, snail surveys were carried out in theSenegal River Basin at Lampsar, in a natural ‘marigot’,and at Richard Toll, in an irrigation canal. Lymnaea natalensis.Bulinus guernet^* and B.forskalii, were regularly found at boththe sites. Bulinus globosus/jousseaumei and B. umbilicatus wereonly present at Lampsar. A decrease of the snail density wasobserved during the rainy season at Lampsar. The recent appearanceof Biomphalaria pfeifferi at Richard Toll is discussed. Thedata show that adult B. pfeiffert are present in the main irrigationcanal all through the year. Consequently parasite transmissionwill be possible throughout the year as well. (Received 23 October 1991; accepted 20 May 1992)