Pectin Methylesterase of Datura species,purification, and characterization from Datura stramoniumand its application

Pectin methylesterases (PME; EC 3.1.1.11) involved in de-esterification of pectin and have applicability in food, textiles, wines, pulp, and paper industries. In the present study, we compared PME activity of different parts of 3 Datura species and found that fruit coat showed maximum PME activity followed by leaf and seed. PME from leaves of D. stramonium (DsPME) was purified and characterized. DsPME showed optimum activity at 60 °C and pH 9 in the presence of 0.3 M NaCl. DsPME was stable at 70 °C and retained more than 40% activity after 60 min of incubation. However, enzyme activity completely abolished at 80 after 5 min of incubation. It follows Michaelis-Menten enzyme kinetics. Km and Vmax with citrus pectin were 0.008 mg/ml and 16.96 µmol/min, respectively. DsPME in combination with polygalactourenase (PGA) increased the clarity of orange, apple, pomegranate and pineapple juices by 2.9, 2.6, 2.3, and 3.6 fold, respectively in comparison to PGA alone. Due to very high de-esterification activity, easy denaturation and significant efficacy in incrementing clarification of fruit juice makes DsPME useful for industrial application.     

A Ty1-copia group retrotransposon sequence in a vertebrate.

Summary We have used the polymerase chain reaction (PCR) to isolate a sequence characteristic of aTy1-copia group retrotransposon from the genome of the herring (Clupea harengus). This is the firstTy1-copia group retrotransposon sequence described in a vertebrate. Phylogenetic comparison of this sequence with other members of this group of retrotransposons shows that it resembles more closely some Tyl-copia group members fromDrosophila melanogaster than other group members in plants and fungi. These observations provide further evidence that theTy1-copia group LTR retrotransposons span many of the major eukaryote species boundaries, suggesting that horizontal transmission between different species has played a role in the evolution of this retrotransposon group.     

Ty1-copia group retrotransposons and the evolution of retroelements in the eukaryotes

Ty1-copia group retrotransposons are among the best studied transposable elements in the eukaryotes. This review discusses the extent of these transposons in the eukaryote kingdoms and compares models for the evolution of these genetic elements in the light of recent phylogenetic data. These data show that the Ty1-copia group is widespread among invertebrate eukaryotes, especially in the higher plant kingdom, where these genetic elements are unusually common and heterogeneous in their sequence. The phylogenetic data also suggest that the present day spectrum of Ty1-copia group retrotransposons has been influenced both by divergence during vertical transmission down evolving lineages and by horizontal transmission between distantly related species. Lastly, the factors affecting Ty1-copia group retrotransposon copy number and sequence heterogeneity in eukaryotic genomes and the effects of transpositional quiescence and defective retrotransposons upon evolution of Ty1-copia group retrotransposons are discussed.     

Selection of somatic hybrids after fusion of protoplasts from Datura innoxia Mill. and Atropa belladonna L.

After fusion of protoplasts from a diploid (2n=24) and a tetraploid (4n=48) chlorophyll-deficient mutant of Datura innoxia Mill. with diploid (2n=72) green wild-type protoplasts of Atropa belladonna L. thirteen somatic hybrids could be selected, most of which had already started to produce leaves and shoots. Hybrid calli were recognizable by the production of hairs, typical for Datura innoxia, and the green colour, derived from Atropa belladonna. Further proof for the hybrid nature was furnished by cytological investigations. The metaphase chromosomes of both species are easily distinguishable in their size: chromosomes of Datura innoxia are about twice as large as those of Atropa belladonna. The chromosome numbers of the hybrids varied from ca. 84 to ca. 175.Abbreviations BAP 6-benzylaminopurine - NAA -naphthalene acetic acid     

Pea Ty1-copia group retrotransposons: transpositional activity and use as markers to study genetic diversity in Pisum

The variation in transposition history of different Ty1-copia group LTR retrotransposons in the species lineages of the Pisum genus has been investigated. A heterogeneous population of Ty1-copia elements was isolated by degenerate PCR and two of these (Tps12 and Tps19) were selected on the basis of their copy number and sequence conservation between closely related species for further in-depth study of their transpositional history in Pisum species. The insertional polymorphism of these elements and the previously characterised PDR1 element was studied by sequence-specific amplification polymorphism (SSAP). Each of these elements reveals a unique transpositional history within 55 diverse Pisum accessions. Phylogenetic trees based on the SSAP data show that SSAP markers for individual elements are able to resolve different species lineages within the Pisum genus. Finally, the SSAP data from all of these retrotransposon markers were combined to reveal a detailed picture of the intra and inter-species relationships within Pisum. Received: 23 January 2000 / Accepted: 24 March 2000     

Transformation of haploid Datura innoxia protoplasts and analysis of the plasmid integration pattern in regenerated transgenic plants

We developed a highly efficient transformation protocol for the PEG-mediated direct transfer of plasmid DNA into protoplasts of haploid Datura innoxia. Vectors harbouring a neomycin phosphotransferase II gene or a hygromycin B phosphotransferase gene under the control of different promoters were used in the transformation experiments. Various amounts of plasmid DNA were applied without any carrier DNA to show the direct influence of the plasmid DNA concentration on the transformation efficiency. Approximately 95% of the selected calli were regenerated to plants; 20% of them remained haploid. Total DNA of different transgenic plants was analysed with regard to the integration pattern of the plasmid DNA. Plants carrying only one or two copies of the vector DNA were observed as well as individuals with multi-copy integration (up to ten or more copies).Abbreviations ATF/RTF absolute/relative transformation frequency - BAP 6-benzylaminopurine - CaMV cauliflower mosaic virus - CTAB N-cetyl-N,N,N-trimethyl-ammonium bromide - HPT hygromycin B phosphotransferase gene - PEG polyethyleneglycol - MES 2-(N-morpholino) ethanesulfonic acid - NPT II neomycin phosphotransferase II gene     

Isolation and characterization of two novel retrotransposons of the Ty1-copia group in oat genomes

Two repetitive sequences, As32 and As22, of 826 and 742 bp, respectively, were isolated from Avena strigosa (As genome). Databank searches revealed their high homology to different segments of the family of Ty1-copia retrotransposons. Southern hybridization showed them to be present in diploid and polyploid oat species. Polymerase chain reaction with primers designed to amplify the segment between them showed that As32 and As22 sequences are composed of two different Ty1-copia retrotransposons. The segment amplified from the pAs32 insert was 2,264 bp long and contained the entire GAG and AP domains, and more than half of the IN domain. This new element has been designated TAS-1 (transposon, A. strigosa, 1) and appears to contain a long open reading frame that encodes a polypeptide of 625 amino acids. Slot-blot and fluorescence in situ hybridization analyses revealed it to be a component of both A- and D-genome chromosomes. Further, the chromosomes involved in one C-A intergenomic translocation in A. murphyi (AC genomes), one C-D intergenomic translocation in A. byzantina cv. Kanota (ACD genomes), and two C-D intergenomic translocations in A. sativa cv. Extra Klock, were identified. Based on its physical distribution and Southern hybridization pattern, a parental retro-transposon represented by TAS-1 appears to have been active at least twice during the evolution of the genomes in species of Avena.     

裸燕麦Ty1-copia类反转录转座子反转录酶序列的分离、鉴定与分析

本研究根据Ty1-copia类反转录转座子反转录酶的保守区设计简并引物,通过PCR扩增,从裸燕麦(Avena nuda L.)品种‘品燕1号’基因组中分离获得23条Ty1-copia类反转录转座子序列,并对序列特征、系统发育关系及其转录活性进行分析。结果显示,23条Ty1-copia类反转录转座子存在较高的异质性,序列间的一致性为45%～98%,存在插入、移码和终止密码突变,但频率不高;系统发育分析结果表明,燕麦Ty1-copia类反转录转座子在进化过程中主要为垂直传递。本研究通过检索燕麦基因表达数据库,发现了5个有转录活性的Ty1-copia类反转录转座子。     

A review of Rheocricotopus (Psilocricotopus) chalybeatus species group from China,with the description of three new species (Diptera,Chironomidae)

The Rheocricotopus (Psilocricotopus) chalybeatus species group from China is reviewed. Three new species, R. (P.) brochus sp. n., R. (P.) rotundus sp. n. and R. (P.) serratus sp. n. are described as adult males. R. (P.) imperfectus Makarchenko & Makarchenko, 2005, R. (P.) robacki (Beck & Beck, 1964) and R. (P.) valgus Chaudhuri & Sinharay, 1983 are recorded from China for the first time and annotated. The diagnosis for the species group is emended and a key to adult males of the species group in China is presented.     

Population dynamics of five anopheles species of the Hyrcanus group in northern Gyeonggi-do, Korea

To investigate the population densities of potential malaria vectors, Anopheles species were collected by light traps in malaria endemic areas, Paju and Gimpo, Gyeonggi-do of Korea. Five Anopheles Hyrcanus sibling species (An. sinensis, An. pullus, An. lesteri, An. kleini, and An. belenrae) were identified by PCR. The predominant species, An. pullus was collected during the late spring and mid-summer, while higher population consists of An. sinensis were collected from late summer to early autumn. These 2 species accounted for 92.1% of all Anopheles mosquitoes collected, while the other 3 species accounted for 7.9%. Taking into account of these population densities, late seasonal prevalence, and long-term incubation period (9-13 months) of the Korean Plasmodium vivax strain, An. sinensis s.s is thought to play an important role in the transmission of vivax malaria in the study areas.     

Paramphistomum daubneyi: characteristics of infection in three lymnaeid species

Experimental infections of two South American lymnaeids (Lymnaea neotropica and L. viatrix var. ventricosa) with Paramphistomum daubneyi were carried out to determine if these snail species could sustain larval development of this digenean and, if so, to specify their potential for cercarial production. A French population of Galba truncatula infected and raised according to the same protocol served as controls. In both experiments, prevalence of P. daubneyi infections in snails did not significantly differ from each other. In snail groups evaluated for cercarial shedding (first experiment), a significantly lower number of shed cercariae was noted for L. neotropica, while those from G. truncatula and L. v. ventricosa did not differ significantly from each other. Dissection of infected snails at day 65 post-exposure at 20 °C (second experiment) found significantly lower burdens of P. daubneyi rediae and cercariae in the bodies of L. neotropica than in those of G. truncatula and L. v. ventricosa. Compared to total cercarial production observed in dissected snails, the percentage of cercariae which exited from snails was 75.6% for G. truncatula, 21.6% for L. neotropica, and 91.4% for L. v. ventricosa. This last species seems to be a good candidate for metacercarial production of P. daubneyi.     

The ant genus Carebara Westwood (Hymenoptera,Formicidae): synonymisation of Pheidologeton Mayr under Carebara,establishment and revision of the C. polita species group

In this paper the genus Pheidologeton Mayr, 1862 is synonymized under Carebara Westwood, 1840 and the Carebara polita group is established and revised. This species group currently includes six species from the Afrotropical region (C. madibai, C. nicotianae, C. perpusilla, C. polita, C. silvestrii, and C. villiersi) and two species from the Neotropical region (C. brevipilosa and C. urichi). The polita group clearly links Carebara and Pheidologeton, and, due to a lack of autapomorphic characters for the latter, a separation of the two genera is no longer justified. As a result Carebara is presented as a monophyletic and better defined genus that can be separated from other genera with more confidence. We present an overview of the distribution and biology of Carebara as well as images from the various genera currently in synonymy under Carebara, and discuss the characters they share. The polymorphism present in Afrotropical and Malagasy Carebara is discussed and one new species from Africa, C. madibai sp. n., is described. The subspecies Carebara perpusilla arnoldiana syn. n., Carebara perpusilla concedens syn. n., and Carebara perpusilla spinosa syn. n. are new synonyms of Carebara perpusilla. Oligomyrmex politus nicotianae is re-elevated to species level and transferred into Carebara, C. nicotianae comb. n., stat. rev.; C. punctata is a new synonym of C. silvestrii comb. n. and C. pygmaea albipes comb. n., syn n., C. pygmaea bugnioni comb. n., syn. n., and C. simularensis syn. n. are new synonyms of C. pygmaea comb. n.. The following names are transferred from Pheidologeton to Carebara as new combinations (with the species epithets adjusted to female endings where necessary): aberrans, affinis, affinis javana, affinis minor, affinis spinosior, affinis sumatrensis, ceylonensis, dentiviris, diversa, diversa draco, diversa ficta, diversa laotina, diversa macgregori, diversa philippina, diversa standfussi, diversa taprobanae, diversa tenuirugosa, diversa williamsi, hammoniae, hostilis, kunensis, latinoda, maccus, mayri, melanocephala, melasolena, nana, nanningensis, obscura, petulens, pullata, pungens, pygmaea, rubra, rugiceps, rugosa, schossnicensis, silena, silvestrii, solitaria, transversalis, trechideros, varia, vespilla, volsellata, yanoi, and zengchengensis. Three new combinations are creating secondary junior homonyms and are here replaced with new names: C. mayri (Santschi, 1928) = C. gustavmayri nom. n., C. rugosa (Karavaiev, 1935) = C. rugoflabella nom. n., and C. silvestrii (Wheeler, 1929b) = C. luzonensis nom. n. Two new combinations are creating secondary junior homonyms among species already in Carebara: C. taprobanae (Forel, 1911a) = C. sinhala nom. n., and C. nana Santschi, 1919 = C. pumilia nom. n.     

Systematics of Australian Thrasorinae (Hymenoptera, Cynipoidea, Figitidae) with descriptions of Mikeiinae, new subfamily, two new genera, and three new species

The Australian Thrasorinae are revised and Mikeius is transferred to Mikeiinae Paretas-Martínez & Pujade-Villar, subfam. n., and Mikeius clavatus Pujade-Villar & Restrepo-Ortiz, sp. n., is described. Two new genera of Thrasorinae are erected: Cicatrix Paretas-Martínez, gen. n., including Cicatrix pilosiscutum(Girault), comb. n. from Amblynotus, Cicatrix schauffi (Buffington), comb. n. from Mikeius, and Cicatrix neumannoides Paretas-Martínez & Restrepo-Ortiz, sp. n.; and Palmiriella Pujade-Villar & Paretas-Martínez, gen. n., including Palmiriella neumanni (Buffington), comb. n. from Mikeius, Thrasorus rieki Paretas-Martínez & Pujade-Villar, sp. n., is also described. A phylogenetic analysis of 176 morphological and biological characters, including all these new taxa and all genera previously included in Thrasorinae, was conducted. All subfamilies were recovered as monophyletic, with the following relationships: Parnipinae (Euceroptrinae (Mikeiinae (Plectocynipinae (Thrasorinae)))). A worldwide key to the subfamilies of Figitidae is provided that includes the new subfamily, as well as a key to genera Thrasorinae.     

Oviposition behaviour of four ant parasitoids (Hymenoptera, Braconidae, Euphorinae, Neoneurini and Ichneumonidae, Hybrizontinae), with the description of three new European species

The oviposition behaviour of four ant parasitoids was observed and filmed for the first time. The movies are available from YouTube (search for Elasmosoma, Hybrizon, Kollasmosoma and Neoneurus). Two of the observed species (Neoneurus vesculussp. n. and Kollasmosoma sentumsp. n.) are new to science. A third species (Neoneurus recticalcarsp. n.) is described from Slovakia and Norway. Keys to the Palaearctic species of the genera Neoneurus and Kollasmosoma are added.