Displaying publications 481 - 500 of 928 in total

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  1. Nucleoprotein gene analysis of fixed and street rabies virus variants using RT-PCR
    Arai YT, Yamada K, Kameoka Y, Horimoto T, Yamamoto K, Yabe S, et al.
    Arch Virol, 1997;142(9):1787-96.
    PMID: 9672637
    A simple and rapid single-step reverse transcriptase-polymerase chain reaction (RT-PCR) was used to investigate the nucleoprotein (N) gene of 11 rabies viruses. A conserved set of RT-PCR primers was designed to amplify the most variable region in the N gene. N gene regions were amplified from 6 fixed laboratory viruses, 4 street viruses from dogs in Thailand, and a horse in Zambia. Sequences of the amplified products, together with the database of 91 additional sequences, were analyzed by using PILEUP program of the GCG package. The rabies viruses grouped into at least 9 distinct clusters by < 90% nucleotide similarity of the N gene region: I (4 isolates, USA), II (2 isolates, South America), III (3 isolates, Africa), IV (52 strains, Europe, Middle East, Africa and South America), V (16 isolates, North America and Arctic), VI (17 isolates, Africa), VII (1 isolate, Africa), VIII (6 isolates, Thailand and Malaysia) and IX (1 isolate, Sri Lanka). A unique group of rabies viruses from Thailand and clusters of isolates corresponding to their geographic origin also were determined. The simple and rapid single-step RT-PCR proved to be useful for identifying rabies viruses, and for grouping the viruses into clades by sequence analysis.
    Matched MeSH terms: Molecular Sequence Data
  2. HIV-1 variants in South and South-East Asia
    Tsuchie H, Saraswathy TS, Sinniah M, Vijayamalar B, Maniar JK, Monzon OT, et al.
    Int J STD AIDS, 1995 Mar-Apr;6(2):117-20.
    PMID: 7779924 DOI: 10.1177/095646249500600211
    HIV spread in South and South-East Asia is most alarming, and genetic variability of HIV-1 is an important consideration in vaccine development. In this study, we examined the third variable (V3) region of env gene of HIV-1 variants prevalent in Thailand, Malaysia, India, and the Philippines. By phylogenetic tree analyses, an HIV-1 variant from an injecting drug user (IDU) in Thailand belonged to subtype B, and HIV-1 variants from 2 IDUs in Malaysia were classified into 2 subtypes, B and E. One HIV-1 variant from a male homosexual in the Philippines belonged to subtype B. Out of 8 HIV-1 variants from sexually transmitted disease patients in India, 7 belonged to subtype C, and one to subtype A. Although the total number of individuals examined in this study was limited, 4 HIV-1 subtypes were found in South and South-East Asia and large international movements of HIV-1-infected individuals in this region could induce global dissemination of these HIV-1 variants.
    Matched MeSH terms: Molecular Sequence Data
  3. Purification and properties of the L-amino acid oxidase from Malayan pit viper (Calloselasma rhodostoma) venom
    Ponnudurai G, Chung MC, Tan NH
    Arch Biochem Biophys, 1994 Sep;313(2):373-8.
    PMID: 8080286
    The L-amino acid oxidase of Malayan pit viper (Calloselasma rhodostoma) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was 132,000 as determined by Sephadex G-200 gel filtration chromatography and 66,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It is a glycoprotein, has an isoelectric point of 4.4, and contains 2 mol of flavin mononucleotide per mole of enzyme. The N-terminal amino acid sequence of the enzyme was A-D-D-R-N-P-L-A-E-E-F-Q-E-N-N-Y-E-E-F-L. Kinetic studies suggest the presence of a alkyl side-chain binding site in the enzyme and that the binding site comprises at least four hydrophobic subsites. The characteristics of the binding site differ slightly from those of cobra venom L-amino acid oxidases.
    Matched MeSH terms: Molecular Sequence Data
  4. Geographical genetic structure within the human lung fluke, Paragonimus westermani, detected from DNA sequences
    Blair D, Agatsuma T, Watanobe T, Okamoto M, Ito A
    Parasitology, 1997 Oct;115 ( Pt 4):411-7.
    PMID: 9364568
    Nucleotide sequences were obtained for the second internal transcribed spacer of the ribosomal gene repeat and for part of the mitochondrial-cytochrome c oxidase subunit I gene from geographical isolates of Paragonimus westermani from Japan, China, Korea, Taiwan, the Philippines, peninsular Malaysia and Thailand. Sequences were obtained from several other species of Paragonimus for comparative purposes. Two groups were recognized within P. westermani: an NE group (China, Japan, Korea, Taiwan) which was relatively uniform and included both diploid and triploid forms, and a southern group (Malaysia, Thailand, Philippines), members of which were genetically distant from one another. According to both ITS2 and COI data, genetic distances among P. westermani isolates equalled or exceeded those between some distinct species of Paragonimus. The ITS2 sequences were conserved relative to COI sequences. Substitutions among the latter may be approaching saturation within the genus Paragonimus.
    Matched MeSH terms: Molecular Sequence Data
  5. Immunological characterization of rice tungro spherical virus coat proteins and differentiation of isolates from the Philippines and India
    Druka A, Burns T, Zhang S, Hull R
    J Gen Virol, 1996 Aug;77 ( Pt 8):1975-83.
    PMID: 8760450
    Rice tungro spherical virus (RTSV) has an RNA genome of more than 12 kb with various features which classify it as a plant picornavirus. The capsid comprises three coat protein (CP) species, CP1, CP2 and CP3, with predicted molecular masses of 22.5, 22.0 and 33 kDa, respectively, which are cleaved from a polyprotein. In order to obtain information on the properties of these proteins, each was expressed in E. coli, purified as a fusion to the maltose-binding protein and used for raising a polyclonal antiserum. CP1, CP2 and CP3 with the expected molecular masses were detected specifically in virus preparations. CP3 is probably the major antigenic determinant on the surface of RTSV particles, as was shown by ELISA, Western blotting and immunogold electron microscopy using antisera obtained against whole virus particles and to each CP separately. In some cases, especially in crude extracts, CP3 antiserum detected several other proteins (40-42 kDa), which could be products of CP3 post-translational modification. No serological differences were detected between the three CPs from isolates from the Philippines, Thailand, Malaysia and India. The CP3-related 40-42 kDa proteins of the Indian RTSV isolate have a slightly higher electrophoretic mobility (42-44 kDa) and a different response to cellulolytic enzyme preparations, which allows them to be differentiated from south-east Asian isolates.
    Matched MeSH terms: Molecular Sequence Data
  6. A ferulic acid ester of sucrose and other constituents of Bhesa paniculata
    Harrison LJ, Sia GL, Sim KY, Tan HT, Connolly JD, Lavaud C, et al.
    Phytochemistry, 1995 Apr;38(6):1497-500.
    PMID: 7786481
    A novel derivative of sucrose, beta-(3,6-di-O-feruloyl)-fructofuranosyl-alpha-(2,3,4,6-tetra-O-ac etyl)- glucopyranoside, was isolated from the wood of Bhesa paniculata. Its structure was determined by a combination of 2D 1H-1H and 1H-13C correlation NMR spectroscopy. The known compounds, glycerol 1-9',12'-octadecadienoate, beta-sitosterol, (+/-)-pinoresinol, methyl 3,4-dihydroxybenzoate, 4-hydroxy-3-methoxybenzoic acid, anofinic acid and 2-(1'-methylethenyl)-benzofuran-5-carboxylic acid were also isolated.
    Matched MeSH terms: Molecular Sequence Data
  7. Therapeutic prospects of bradykinin receptor antagonists
    Sharma JN
    Gen. Pharmacol., 1993 Mar;24(2):267-74.
    PMID: 8387049
    1. Bradykinin and related kinins may act on four types of receptors designated as B1, B2, B3 and B4. It seems that the B2 receptors are most commonly found in various vascular and non-vascular smooth muscles, whereas B1 receptors are formed in vitro during trauma, and injury, and are found in bone tissues. 2. These BK receptors are involved in the regulations of various physiological and pathological processes. 3. The mode of kinin actions are based upon the interactions between the kinin and their specific receptors, which can lead to activation of several second-messenger systems. 4. Recently, numerous BK receptors antagonists have been synthesized with prime aim to treat diseases caused by excessive kinin production. 5. These diseases are RA, inflammatory diseases of the bowel, asthma, rhinitis and sore throat, allergic reactions, pain, inflammatory skin disorders, endotoxin and anaphylactic shock and coronary heart diseases. 6. On the other hand, BK receptor antagonists could be contraindicated in hypertension, since these drugs may antagonize the antihypertensive therapy and/or may trigger the hypertensive crisis. 7. It is worth suggesting that the BK receptor agonists might be useful antihypertensive drugs.
    Matched MeSH terms: Molecular Sequence Data
  8. Fulltext Nucleotide and encoded amino acid sequences of the membrane protein precursor and the membrane protein genes of three dengue-2 viruses isolated in Malaysia from patients with dengue haemorrhagic fever, dengue shock syndrome or dengue fever
    Samuel S, Koh CL, Pang T, Lam SK
    Nucleic Acids Res, 1990 Apr 11;18(7):1905.
    PMID: 2336374 DOI: 10.1093/nar/18.7.1905
    Matched MeSH terms: Molecular Sequence Data
  9. Plasmodium falciparum: gene structure and hydropathy profile of the major merozoite surface antigen (gp195) of the Uganda-Palo Alto isolate
    Chang SP, Kramer KJ, Yamaga KM, Kato A, Case SE, Siddiqui WA
    Exp Parasitol, 1988 Oct;67(1):1-11.
    PMID: 3049134
    The gene encoding the 195,000-Da major merozoite surface antigen (gp195) of the FUP (Uganda-Palo Alto) isolate of Plasmodium falciparum, a strain widely used for monkey vaccination experiments, has been cloned and sequenced. The translated amino acid sequence of the FUP gp195 protein is closely related to the sequences of corresponding proteins of the CAMP (Malaysia) and MAD-20 (Papua New Guinea) isolates and more distantly related to those of the Wellcome (West Africa) and K1 (Thailand) isolates, supporting the proposed allelic dimorphism of gp195 within the parasite population. The prevalence of dimorphic sequences within the gp195 protein suggests that many gp195 epitopes would be group-specific. Despite the extensive differences in amino acid sequence between gp195 proteins of these two groups, the hydropathy profiles of proteins representative of both groups are very similar. The conservation of overall secondary structure shown by the hydropathy profile comparison indicates that gp195 proteins of the various P. falciparum isolates are functionally equivalent. This information on the primary structure of the FUP gp195 protein will enable us to evaluate the possible roles of conserved, group-specific and variable epitopes in immunity to the blood stage of the malaria parasite.
    Matched MeSH terms: Molecular Sequence Data
  10. Codiversification in an ant-plant mutualism: stem texture and the evolution of host use in Crematogaster (Formicidae: Myrmicinae) inhabitants of Macaranga (Euphorbiaceae)
    Quek SP, Davies SJ, Itino T, Pierce NE
    Evolution, 2004 Mar;58(3):554-70.
    PMID: 15119439
    We investigate the evolution of host association in a cryptic complex of mutualistic Crematogaster (Decacrema) ants that inhabits and defends Macaranga trees in Southeast Asia. Previous phylogenetic studies based on limited samplings of Decacrema present conflicting reconstructions of the evolutionary history of the association, inferring both cospeciation and the predominance of host shifts. We use cytochrome oxidase I (COI) to reconstruct phylogenetic relationships in a comprehensive sampling of the Decacrema inhabitants of Macaranga. Using a published Macaranga phylogeny, we test whether the ants and plants have cospeciated. The COI phylogeny reveals 10 well-supported lineages and an absence of cospeciation. Host shifts, however, have been constrained by stem traits that are themselves correlated with Macaranga phylogeny. Earlier lineages of Decacrema exclusively inhabit waxy stems, a basal state in the Pachystemon clade within Macaranga, whereas younger species of Pachystemon, characterized by nonwaxy stems, are inhabited only by younger lineages of Decacrema. Despite the absence of cospeciation, the correlated succession of stem texture in both phylogenies suggests that Decacrema and Pachystemon have diversified in association, or codiversified. Subsequent to the colonization of the Pachystemon clade, Decacrema expanded onto a second clade within Macaranga, inducing the development of myrmecophytism in the Pruinosae group. Confinement to the aseasonal wet climate zone of western Malesia suggests myrmecophytic Macaranga are no older than the wet forest community in Southeast Asia, estimated to be about 20 million years old (early Miocene). Our calculation of COI divergence rates from several published arthropod studies that relied on tenable calibrations indicates a generally conserved rate of approximately 1.5% per million years. Applying this rate to a rate-smoothed Bayesian chronogram of the ants, the Decacrema from Macaranga are inferred to be at least 12 million years old (mid-Miocene). However, using the extremes of rate variation in COI produces an age as recent as 6 million years. Our inferred timeline based on 1.5% per million years concurs with independent biogeographical events in the region reconstructed from palynological data, thus suggesting that the evolutionary histories of Decacrema and their Pachystemon hosts have been contemporaneous since the mid-Miocene. The evolution of myrmecophytism enabled Macaranga to radiate into enemy-free space, while the ants' diversification has been shaped by stem traits, host specialization, and geographic factors. We discuss the possibility that the ancient and exclusive association between Decacrema and Macaranga was facilitated by an impoverished diversity of myrmecophytes and phytoecious (obligately plant inhabiting) ants in the region.
    Matched MeSH terms: Molecular Sequence Data
  11. Cloning, expression and characterization of sugarcane (Saccharum officinarum L.) transketolase
    Kalhori N, Nulit R, Go R
    Protein J, 2013 Oct;32(7):551-9.
    PMID: 24132392 DOI: 10.1007/s10930-013-9516-z
    Pentose phosphate pathway (PPP) composed of two functionally-connected phases, the oxidative and non-oxidative phase. Both phases catalysed by a series of enzymes. Transketolase is one of key enzymes of non-oxidative phase in which transfer two carbon units from fructose-6-phosphate to erythrose-4-phosphate and convert glyceraldehyde-3-phosphate to xylulose-5-phosphate. In plant, erythrose-4-phosphate enters the shikimate pathway which is produces many secondary metabolites such as aromatic amino acids, flavonoids, lignin. Although transketolase in plant system is important, study of this enzyme is still limited. Until to date, TKT genes had been isolated only from seven plants species, thus, the aim of present study to isolate, study the similarity and phylogeny of transketolase from sugarcane. Unlike bacteria, fungal and animal, PPP is complete in the cytosol and all enzymes are found cytosolic. However, in plant, the oxidative phase found localised in the cytosol but the sub localisation for non-oxidative phase might be restricted to plastid. Thus, this study was conducted to determine subcellular localization of sugarcane transketolase. The isolation of sugarcane TKT was done by reverse transcription polymerase chain reaction, followed by cloning into pJET1.2 vector and sequencing. This study has isolated 2,327 bp length of sugarcane TKT. The molecular phylogenetic tree analysis found that transketolase from sugarcane and Zea mays in one group. Classification analysis found that both plants showed closer relationship due to both plants in the same taxon i.e. family Poaceae. Target P 1.1 and Chloro P predicted that the compartmentation of sugarcane transketolase is localised in the chloroplast which is 85 amino acids are plant plastid target sequence. This led to conclusion that the PPP is incomplete in the cytosol of sugarcane. This study also found that the similarity sequence of sugarcane TKT closely related with the taxonomy plants.
    Matched MeSH terms: Molecular Sequence Data
  12. Genes involved in alkane degradation in the Alcanivorax hongdengensis strain A-11-3
    Wang W, Shao Z
    Appl Microbiol Biotechnol, 2012 Apr;94(2):437-48.
    PMID: 22207216 DOI: 10.1007/s00253-011-3818-x
    Alcanivorax hongdengensis A-11-3 is a newly identified type strain isolated from the surface water of the Malacca and Singapore Straits that can degrade a wide range of alkanes. To understand the degradation mechanism of this strain, the genes encoding alkane hydroxylases were obtained by PCR screening and shotgun sequencing of a genomic fosmid library. Six genes involved in alkane degradation were found, including alkB1, alkB2, p450-1, p450-2, p450-3 and almA. Heterogeneous expression analysis confirmed their functions as alkane oxidases in Pseudomonas putida GPo12 (pGEc47ΔB) or Pseudomonas fluorescens KOB2Δ1. Q-PCR revealed that the transcription of alkB1 and alkB2 was enhanced in the presence of n-alkanes C(12) to C(24); three p450 genes were up-regulated by C(8)-C(16) n-alkanes at different levels, whereas enhanced expression of almA was observed when strain A-11-3 grew with long-chain alkanes (C(24) to C(36)). In the case of branched alkanes, pristane significantly enhanced the expression of alkB1, p450-3 and almA. The six genes enable strain A-11-3 to degrade short (C(8)) to long (C(36)) alkanes that are straight or branched. The ability of A. hongdengensis A-11-3 to thrive in oil-polluted marine environments may be due to this strain's multiple systems for alkane degradation and its range of substrates.
    Matched MeSH terms: Molecular Sequence Data
  13. Molecular basis of beta thalassemia in the south of Thailand
    Laosombat V, Fucharoen SP, Panich V, Fucharoen G, Wongchanchailert M, Sriroongrueng W, et al.
    Am J Hematol, 1992 Nov;41(3):194-8.
    PMID: 1415194
    A total of 103 beta thalassemia genes from 78 children (45 with Hb E/beta thalassemia, 8 with beta thalassemia heterozygotes, and 25 with homozygous beta thalassemia) were analyzed using dot-blot hybridization of the polymerase chain reaction-amplified DNA and direct DNA sequencing. Nine mutations were characterized in 98/103 (95%) of beta thalassemia alleles, of which six (a 4 bp deletion in codons 41-42, a G-C transition at position 5 of IVS-1, A-G transition at codon 19, an A-T transition at codon 17, an A-G transition at position -28 upstream of the beta globin gene, a G-T transition at position 1 of IVS-1), accounted for 92%. The spectrum of beta thalassemia mutations in Chinese Thai is similar to that reported among the Chinese from other parts of the world. The distribution of beta thalassemia mutations in Muslim Thai is similar to that reported among Malaysians. The most common beta thalassemia mutation in Thai and Chinese Thai patients is the frameshift mutation at codons 41-42, in comparison with the Muslim Thai in whom the G-C transition at position 5 of the IVS-1 mutation predominates. The heterogeneity of molecular defects causing beta thalassemia should aid in the planning of a prenatal diagnosis program for beta thalassemia in the South of Thailand.
    Matched MeSH terms: Molecular Sequence Data
  14. The rubber elongation factor of rubber trees (Hevea brasiliensis) is the major allergen in latex
    Czuppon AB, Chen Z, Rennert S, Engelke T, Meyer HE, Heber M, et al.
    J Allergy Clin Immunol, 1993 Nov;92(5):690-7.
    PMID: 8227860
    BACKGROUND: Allergy to latex-containing articles is becoming more and more important because it can result in unexpected life-threatening anaphylactic reactions in sensitized individuals.

    METHODS: A protein of 58 kd with an isoelectric point of 8.45 was purified from raw latex and from latex gloves and identified as the major allergen, completely blocking specific IgE antibodies in the serum of latex-sensitized subjects. The allergen is a noncovalent homotetramer molecule, in which the 14.6 kd monomer was identified, by amino acid composition and sequence homologies of tryptic peptides, to be the rubber elongation factor found in natural latex of the Malaysian rubber tree.

    RESULTS: Competitive immunoinhibition tests showed that the starch powder covering the finished gloves is the airborne carrier of the allergen, resulting in bronchial asthma on inhalation. The purified allergen can induce allergic reactions in the nanogram range.

    CONCLUSION: The identification of the allergen (Hev b I) may help to eliminate it during the production of latex-based articles in the future.

    Matched MeSH terms: Molecular Sequence Data
  15. Genetic variability of classical swine fever virus
    Vilcek S, Stadejek T, Ballagi-Pordány A, Lowings JP, Paton DJ, Belák S
    Virus Res, 1996 Aug;43(2):137-47.
    PMID: 8864203
    The genetic variability of classical swine fever virus was studied by comparative nucleotide sequence analysis of 76 virus isolates, collected during a half century from three continents. Parts of the E2 (gp55) and the polymerase gene coding regions of the viral genome were amplified by RT-PCR and DNA fragments of 254 and 207 bp, respectively, were sequenced. The comparative sequence analysis of the E2 region revealed two main phylogenetic groups of CSFV, indicating that the virus apparently evolved from two ancestor nodes. Group I (represented by Brescia strain) consisted of old and recent American and Asian viruses, as well as old English isolates from the 1950s. This group was subdivided into three subgroups, termed I.A-I.C. Group II (represented by Alfort strain) consisted of relatively recent isolates from Europe, together with strain Osaka, which was isolated in Japan from a pig of European origin. Based on genetic distances the group was divided into subgroups II.A and II.B. Malaysian isolates were branched into both groups, indicating multiple origins for contemporaneous outbreaks in that country. All ten vaccine strains tested were branched in group I, implying a common ancestor. The Japanese Kanagawa strain, isolated in 1974, and the British Congenital Tremor strain from 1964 were the most distinct variants of CSFV in our collection. The comparison of the nucleotide sequences of the polymerase coding region of 32 European strains distinguished subgroups II.A and II.B which were similar to the corresponding subgroups of the E2 phylogenetic tree. Thus, the results revealed that the E2 region and the polymerase coding regions seem to be appropriate for the grouping of CSFV isolates from all over the world, distinguishing two major groups of the virus. The reliability of these regions for phylogenetic analysis is indicated by the similarity of the results obtained from the two separate parts of the CSFV genome.
    Matched MeSH terms: Molecular Sequence Data
  16. Identification of enterovirus 71 isolates from an outbreak of hand, foot and mouth disease (HFMD) with fatal cases of encephalomyelitis in Malaysia
    AbuBakar S, Chee HY, Al-Kobaisi MF, Xiaoshan J, Chua KB, Lam SK
    Virus Res, 1999 May;61(1):1-9.
    PMID: 10426204
    Thirteen enterovirus 71 (EV71) isolates were obtained from both fatal and non-fatal infections of patients seen in Peninsula Malaysia and in Sarawak during an outbreak of hand, foot and mouth disease (HFMD) in Malaysia in 1997, with incidences of fatal brainstem encephalomyelitis. The isolates were identified using immunofluorescence staining, neutralization assays, and partial sequencing of the 5' untranslated regions (UTR). Assessment of the potential genetic relationships of the isolates using the partial 5'UTR sequences suggested clustering of the isolates into at least two main clusters. Isolates from Peninsula Malaysia were found in both clusters whereas Sarawak-derived isolates clustered only in cluster II. Isolates derived from fatal infections, however, occurred in both clusters and no distinctive nucleotide sequences could be attributed to the fatal isolates. Examination of the nucleotide sequences revealed at least 13 nucleotide positions in all the isolates which differ completely from the previously reported EV71 5'UTR sequences. In addition, at least 11 nucleotide position differences within the 5'UTR were noted which differentiated cluster I from cluster II. Predicted secondary RNA structures drawn using the nucleotide sequences also suggested differences between isolates from the two clusters. These findings suggest the presence of at least two potentially virulent EV71 co-circulating in Malaysia during the 1997 HFMD outbreak.
    Matched MeSH terms: Molecular Sequence Data
  17. Variation in the small subunit ribosomal DNA confirms that Udonella (Monogenea: Udonellidae) is a species-rich group
    Freeman MA, Ogawa K
    Int J Parasitol, 2010 Feb;40(2):255-64.
    PMID: 19715695 DOI: 10.1016/j.ijpara.2009.08.006
    Numerous global reports of the species Udonella caligorum, currently thought to be a species complex, suggests that the group may be species-rich. Herein we describe Udonella fugu n. sp., previously described as U. caligorum, found on the parasitic copepod Pseudocaligus fugu infecting Takifugu spp. from Japan. Using morphological data U. fugu can be distinguished from the current valid species by at least one of the traditionally used characters in udonellid taxonomy, and phylogenetic analyses of ssrDNA sequence data for U. fugu and other udonellids confirm that U. fugu forms a distinct clade from other udonellids including U. caligorum. Variable regions in the ssrDNA demonstrated a range of between 2.75 and 5.5% difference between currently recognized species of Udonella. These differences in ssrDNA sequences are phylogenetically useful when distinguishing between morphologically similar udonellids and can be used in conjunction with other data (morphology, phylogeography and fish host) to help clarify udonellid systematics. Udonella fugu was also found to cause significant damage to farmed tiger puffers through their feeding activities. Individual skin lesions were round in shape but merged with adjoining lesions to form more extensive lacerations. In some of the specimens from P. fugu infecting Takifugu niphobles, the protozoan ciliate Trichodina was found on the udonellid body surface and in their intestinal contents. We conclude that the udonellids are a more species-rich group than currently recognized, that early descriptions of new species may have been synonymized with U. caligorum in error and that the frequent global reports of U. caligorum may actually represent new species. This has led to a wide range of morphological descriptions for U. caligorum, blurring the usefulness of morphological data for the group.
    Matched MeSH terms: Molecular Sequence Data
  18. Necator americanus (Nematoda: Ancylostomatidae) from Africa and Malaysia have different ITS-2 rDNA sequences
    Romstad A, Gasser RB, Nansen P, Polderman AM, Chilton NB
    Int J Parasitol, 1998 Apr;28(4):611-5.
    PMID: 9602384
    The nucleotide sequences of the second internal transcribed spacer of rDNA were determined for adult worms of Necator americanus originating from Togo (Africa) and Sarawak (Malaysia). The length of the sequences of specimens from Togo (325 bp) were shorter than those from Sarawak (327 bp). There were six fixed genetic differences in the aligned sequences of N. americanus from Sarawak and Togo, excluding one or two polymorphic sites within the sequence of N. americanus from each geographical region. These findings suggest that there is either population variation in the sequence of N. americanus, or that N. americanus from the two countries may represent genetically distinct but morphologically similar (i.e. cryptic) species, however, comparison of the sequence differences among other hookworm species supports the latter conclusion.
    Matched MeSH terms: Molecular Sequence Data
  19. Parasite speciation within or between host species?--phylogenetic evidence from site-specific polystome monogeneans
    Littlewood DT, Rohde K, Clough KA
    Int J Parasitol, 1997 Nov;27(11):1289-97.
    PMID: 9421713
    Partial nuclear 28S ribosomal RNA and mitochondrial cytochrome c oxidase subunit I (COI) gene sequences (953 and 385 nucleotides, respectively) of one fish monogenean (outgroup) and six polystome monogeneans (four Polystomoides spp. from the oral cavities and urinary bladders of freshwater turtles in Australia and Malaya, two Neopolystoma spp. from the urinary bladder and conjunctival sac of a freshwater turtle in Australia) were used to examine the question of whether congeneric species infecting different sites in the same host species have speciated in that host by adapting to different sites, or whether species infecting a particular site in one host have given rise to species infecting the same site in different hosts. Results show unequivocally that congeneric species infecting the same site, even of host species belonging to different suborders and occurring on different continents, are more closely related than congeneric species infecting different sites of the same host species. This is interpreted as meaning that speciation has not occurred in one host. Morphological evolution of polystomes has been very slow: few differences between species and even genera have evolved over a period of at least 150 Myr, and this is matched by low substitution rates of nucleotides, and the ambiguous position of species of different genera, depending on whether COI or 28S rDNA sequences are used.
    Matched MeSH terms: Molecular Sequence Data
  20. Fulltext Characterization and comparative sequence analysis of the DNA mismatch repair MSH2 and MSH7 genes from tomato
    Tam SM, Samipak S, Britt A, Chetelat RT
    Genetica, 2009 Dec;137(3):341-54.
    PMID: 19690966 DOI: 10.1007/s10709-009-9398-3
    DNA mismatch repair proteins play an essential role in maintaining genomic integrity during replication and genetic recombination. We successfully isolated a full length MSH2 and partial MSH7 cDNAs from tomato, based on sequence similarity between MutS and plant MSH homologues. Semi-quantitative RT-PCR reveals higher levels of mRNA expression of both genes in young leaves and floral buds. Genetic mapping placed MSH2 and MSH7 on chromosomes 6 and 7, respectively, and indicates that these genes exist as single copies in the tomato genome. Analysis of protein sequences and phylogeny of the plant MSH gene family show that these proteins are evolutionarily conserved, and follow the classical model of asymmetric protein evolution. Genetic manipulation of the expression of these MSH genes in tomato will provide a potentially useful tool for modifying genetic recombination and hybrid fertility between wide crosses.
    Matched MeSH terms: Molecular Sequence Data
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