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PubMed1992

L-myc and N-myc influence lineage determination in the central nervous system.

The N-myc and the L-myc proto-oncogenes are expressed during embryonal development mainly in the developing brain. Studies of their expression in single neuroepithelial cells revealed that neural precursors not yet committed to the glial or the neuronal lineage expressed both genes, but after lineage commitment they expressed either N-myc or L-myc. Moreover, enforced expression of L-myc in the neural precursor cell line 2.3D caused neuronal differentiation, while the expression of N-myc promoted glial differentiation. These results indicate that L-myc and N-myc play critical roles in lineage determination for the central nervous system.

Animals↗
PubMed1994

Globose basal cells are neuronal progenitors in the olfactory epithelium: a lineage analysis using a replication-incompetent retrovirus.

We have used a replication-incompetent retrovirus to analyze the lineage of olfactory receptor neurons in young rats. At 5-40 days after infection, clusters of infected cells comprised two major types: one consisted of 1-2 horizontal basal cells, and a second consisted of variable numbers of globose basal cells and immature and mature sensory neurons. Olfactory nerve lesion (which enhances neuronal turnover) increased the frequency of the globose-sensory neuron clusters as well as the number of cells in such clusters. No clusters contained both horizontal and globose basal cells, and none contained sustentacular cells. These data suggest, at least in young rats, that horizontal basal cells are not precursors of olfactory neurons, that there is a lineage path from globose cells to mature neurons, and that sustentacular cells may arise from a separate lineage.

Animals↗
PubMed1990

Clonal variation in gene methylation: c-H-ras and alpha-hCG regions vary independently in human fibroblast lineages.

The stability of DNA methylation has been followed in clonal lineages of human diploid fibroblasts, for the gene regions encoding the c-H-ras proto-oncogene and the alpha subunit of human chorionic gonadotropin (alpha-hCG). Although methylation losses predominated, both de novo gains and losses of cytosine methylation were observed in subclones and sub-subclones, at frequencies which differed between individual clonal lineages, and between the 2 gene regions compared. Methylation of these loci varied independently among clones; e.g., a lineage which showed frequent methylation loss in the c-H-ras gene region remained highly methylated for alpha-hCG, and vice versa. Thus, the fidelity with which DNA methylation is inherited in specific endogenous gene regions must be governed by a clone-specific property affecting local chromatin structure, but apparently not by gene expression per se. Late in the replicative life-span of diploid fibroblasts, as cell replication slowed, restriction patterns for methylation-sensitive enzymes became simpler and more discrete, while those for other enzymes did not change. This is interpreted as a consequence of 'clonal succession', in which the fastest-replicating or longest-lived clones/subclones eventually predominate in a cell population; it could also reflect a decreased rate or a non-random selection of methylation changes in late-passage cells.

Cell Survival↗
PubMed1992

Differential expression of the msp130 gene among skeletal lineage cells in the sea urchin embryo: a three dimensional in situ hybridization analysis.

In order to examine the ontogeny of tissue-specific expression of the msp130 gene during early embryogenesis of the sea urchin, we have developed a whole-mount, non-radioactive in situ hybridization protocol suitable for these embryos. This protocol is adapted from the existing technology of immunohistochemical localization of digoxygenin-labelled hybridization probes in tissue sections. Transcript distribution patterns in the whole embryo are seen in three dimensions, and at much higher resolution and sensitivity than can be achieved using radioactive probes and sectioned material. We have traced the ontogeny of expression of the skeleton-specific gene, msp130, during the development of Strongylocentrotus purpuratus. Transcripts are first detected at the blastula stage, in micromere-lineage cells just prior to ingression. Appearance of msp130 transcripts remains strictly limited to this lineage through the pluteus stage. Estimated from the relative intensity of staining of the PMCs of an embryo, the relative abundance of msp130 transcripts is uniform among the 32 cells of this lineage in secondary mesenchyme blastulae and in gastrulae, indicating that expression is homogeneous among these cells up to the early prism stage. However, the relative intensity of stain, and therefore abundance of transcripts, changes dramatically and in a consistent pattern among the PMCs of an embryo during prism and pluteus stages, suggesting that these cells switch from an autonomous mode of regulation of the msp130 gene, to an inductive mode. In the pluteus larva, the highest levels of expression occur in those cells associated with the rapidly growing tips of the spicular skeleton.

Animals↗
PubMed2006

Adult pancreatic stem/progenitor cells spontaneously differentiate in vitro into multiple cell lineages and form teratoma-like structures.

Cells isolated from pancreas have a remarkable potential for self-renewal and multilineage differentiation. We here present a comprehensive characterisation of stem/progenitor cells derived from exocrine parts of the adult rat pancreas. Using purified cells from either single colonies or even single-cell clones, we specifically demonstrate: (i) the cells contain the typical stem/progenitor cell markers alkaline phophatase, SSEA-1, Oct-4, CD9, Nestin, Pax6, CD44, a-Fetoprotein and Brachyury, demonstrated by immunocytochemistry and RT-PCR; (ii) the cells have the potential to differentiate into lineages of all three germ layers in vitro; (iii) a clonal analysis revealed that even cell lines derived from a single cell have stem/progenitor cell properties such as self-renewal and spontaneous differentiation into various cell lineages; (iv) the cells have the propensity to form three-dimensional, teratoma-like structures in vitro, which contain cells of different lineages; and (v) external stimuli can activate the generation of certain cell types. For instance, cells treated with retinoic acid show an increased expression of alpha-smooth muscle actin. These results suggest that exocrine glands, such as pancreas may be a potential source of adult stem/progenitor cells, suitable for cell therapy of degenerative diseases.

Actins↗
PubMed2006

The 3.6 kb DNA fragment from the rat Col1a1 gene promoter drives the expression of genes in both osteoblast and osteoclast lineage cells.

The type I collagen promoter has been used to develop transgenic constructs that are able to mark different stages of osteoblastic differentiation. The pOBCol3.6 promoter is active in early mesenchymal progenitors, including preosteoblasts and osteoblasts, while the pOBCol2.3 promoter is more restricted, showing expression in mature osteoblasts and osteocytes. Transgenic mouse lines have been created that express various GFP reporters under the control of both promoters. These transgenic mice permit the tracking of osteoblastic lineage progression in vitro. They also represent a system to test lineage progression in vivo after the transplantation of progenitors. A parabiosis system was used in which pOBCol3.6GFP transgenic mice were surgically joined with mice bearing a Col2.3DeltaTK transgene. The Col2.3DeltaTK transgenic mouse bears a herpes thymidine kinase gene driven by the pOBCol2.3 promoter, and upon treatment with gancyclovir (GCV) displays extensive destruction of the bone lining cells. After a common circulation was established, parabiotic pairs were treated with GCV for 15 days. Histological analysis of their bones showed the clear presence of GFP positive cells in the Col2.3DeltaTK parabionts, around trabecular bone and on the endosteal and periosteal surfaces. Stromal cell cultures from these Col2.3DeltaTK parabionts did not display mineralized colonies coexpressing GFP. In contrast, scattered GFP positive clusters that contained large cells with morphology similar to osteoclast like cells (OCLs) were observed. These cells were also TRAP positive. They were readily detected in Col2.3DeltaTK mice treated with GCV and transplanted with purified hematopoietic stem cells (HSCs) isolated from pOBCol3.6GFP mice. OCLs were also generated in vitro from osteoclast progenitor cells obtained from pOBCol3.6GFP mice that were defined by the B220- CD3- CD11b- c-fms+ phenotype. Molecular analysis showed that OCLs did not express type I collagen indicating that the Col3.6 promoter contains elements that are active during osteoclastogenesis and are not strictly related to collagen transcription. In summary, we demonstrate that pOBCol3.6 unexpectedly directs the expression of transgenes in the osteoclast lineage and this effect must be considered when utilizing this promoter to study of mesenchymal progenitor cells.

Animals↗
PubMed2005

Multilocus sequence typing and repetitive element-based polymerase chain reaction analysis of Neisseria meningitidis isolates in Brazil reveal the emergence of 11 new sequence types genetically related to the ST-32 and ST-41/44 complexes and high prevalence of strains related to hypervirulent lineages.

Eighty-four strains of Neisseria meningitidis isolated from patients with meningococcal disease in 4 states of Brazil were analyzed by multilocus sequence typing and repetitive element-based polymerase chain reaction (Rep-PCR). The majority of strains analyzed (82%) belonged to 4 hypervirulent lineages, and 11 of 20 new sequence type (STs) characterized were related to hypervirulent lineages. Sequences of fetA and porA genes were analyzed, and the majority were related to profiles present in the ST-32 complex/electrophoretic type (ET)-5 complex. Rep-PCR analysis showed a unique electrophoretic pattern among strains related to hypervirulent lineages. Considering that 81% of the strains were serogroup B and strains belonging to the ST-32/ET-5 complex are genetically related to the Cuban vaccine strain used in a mass vaccination from 1990 to 1994 in Brazil, we believe that this vaccine did not confer effective herd immunity even among the age group within the vaccine showed higher efficacy. Our results once more raise the question about which strains should be used in the development of a new vaccine against N. meningitidis serogroup B.

Bacterial Proteins↗
PubMed2026

Lineage-specific adaptation and resistance in Candida albicans.

Candida albicans exhibits substantial phenotypic and ecological diversity; however, the exact relationship between its population structure, adaptation to specific niches, and antifungal resistance remains incompletely understood. To investigate these evolutionary dynamics, we analyzed the whole-genome sequences from 591 publicly available isolates, integrating nuclear and mitochondrial phylogenomics with ecological and resistance-associated genomic analyses. Phylogenomic analyses resolved 18 core nuclear clusters together with multiple admixed lineages. Strong cytonuclear concordance was noted in the majority of the central lineages, contrasting with a higher discordance among the admixed groups, consistent with recurrent genetic exchange. The analysis revealed that geographic origin explains a larger fraction of genetic variance than anatomical niche, supporting a predominantly generalist population structure. A notable exception was Cluster N16 (Candida africana), which presented a strict genital origin in our dataset (n = 34). Additionally, although the mitochondrial genome exhibits strong purifying selection, candidate residues under diversifying selection correlated with specific niches (e.g., bloodstream) have been identified. Analysis of five resistance-associated genes (ERG11, UPC2, FKS1, TAC1 and FUR1) revealed that resistance-associated variants were generally rare but exhibited distinct gene-specific patterns. In case of ERG11 and FUR1 they were concentrated in a specific clade (N11, N17, and their admixed Group A) and exhibit gene-dependent zygosity patterns. In summary, the evolution of C. albicans appears to be driven by a predominantly clonal model punctuated by episodic genetic exchange, where both ecological adaptation and antifungal resistance mutations exhibit genomic signatures marked by lineage specificity.

Antifungal resistance↗
PubMed2005

Variable selection pressures across lineages in Trichodesmium and related cyanobacteria based on the heterocyst differentiation protein gene hetR.

Due to the irreversible inhibition of nitrogenase by O2, N2 fixation is incompatible with the oxygenic photosynthesis of cyanobacteria. These organisms have therefore evolved various strategies for growing diazotrophically. One group of N2-fixing cyanobacteria has specialized cells, heterocysts, which contain the nitrogenase, lack the oxygenic photosystem II, and are virtually anoxic inside as the result of respiratory activity and a thick glycolipid cell wall. The hetR gene encodes a serine protease which is thought to be involved in the regulation of heterocyst development and in DNA binding. Although hetR is also present in many non-heterocystous N2-fixing cyanobacteria, its function in these organisms is unknown. In this study, hetR sequences of the N2-fixing, non-heterocystous cyanobacterium Trichodesmium spp. and related genera were examined for signatures of selection. In parsimony- or distance-based hetR phylogenies, the filamentous non-heterocystous cyanobacteria Symploca sp. and Leptolyngbya sp. were closest to Trichodesmium sp. However, accommodating molecular attributes of hetR such as nucleotide frequencies and rate heterogeneity in phylogenetic analyses suggested that many other genera could not be excluded as sister taxa of Trichodesmium. Maximum likelihood analysis of the dN/dS ratio (omega) showed that-irrespective of the use of Symploca, Leptolyngbya, or more distant taxa as an outgroup-the lineage between an outgroup and Trichodesmium (omega1=0.02-0.05) and a lineage leading to Trichodesmium erythraeum (omega1=0.02) were under much stronger purifying selection than the other lineages in Trichodesmium (omega0=0.13-0.32). Although the results from the maximum likelihood analyses are most trustworthy because of codon usage bias in Trichodesmium, the results from a simpler tree-based McDonald-Kreitman test were in general agreement. Due to their quite different assumptions, the combination of these two methods of analysis circumvents multiple testing which, in general, is problematic when using branch models. Although the causal selective forces underlying the substitution patterns in hetR have not yet been identified, these findings parallel the variety of physiological, molecular, and behavioral differences in cyanobacteria related to N2 fixation. The heterogeneity of selection pressures in Trichodesmium is more surprising, because multiple adaptation mechanisms have not been described in this genus.

Bacterial Proteins↗
PubMed2006

Highly sensitive TaqMan RT-PCR assay for detection and quantification of both lineages of West Nile virus RNA.

BACKGROUND: Starting in 1999, the West Nile virus (WNV) epidemic represents the largest outbreak of arboviral encephalitis ever recorded in the U.S. The effective means to determine an infection are detection of viral nucleic acid and/or viral specific immunoglobulin, IgM and/or IgG. OBJECTIVE: To develop a highly sensitive and specific TaqMan RT-PCR assay for the detection and quantification of WNV RNA of lineage 1 and lineage 2. STUDY DESIGN: A TaqMan RT-PCR primer-probe was designed to perfectly match target sequences of all sequenced WNV strains and isolates, which added a layer of protection against false-negative results due to strain variability. In addition, the inclusion of a low level RNA internal control (IC) in the assay increased the precision and accuracy of the assay. RESULTS: By optimizing the RNA preparation procedure for increased WNV RNA recovery, together with optimizing the primer-probe and TaqMan conditions for improved amplification efficiency, we developed a highly sensitive assay with the detection limit of 10 copies/mL. To evaluate the assay, we tested plasma samples from 12 transfusion-transmitted implicated cases in 2002 and from 68 positive blood donors in 2003. All tested specimens were WNV positive. The viral load of 68 positive blood donor samples collected in 2003 ranged from 10 copies/mL to 67,000 copies/mL with a mean of 8100 copies/mL. Furthermore, high sensitivity of the assay was achieved without compromising specificity. All 100 routine donor samples tested negative. CONCLUSIONS: The assay results demonstrate that our in-house TaqMan RT-PCR procedure can detect and quantify WNV RNA of lineage1 and lineage 2 in human plasma with high sensitivity and specificity.

Blood Donors↗
PubMed2026

Genomic insights into the first blaKPC-2-carrying Klebsiella pneumoniae isolate reported in Chile: limited local dissemination of the globally distributed ST101 lineage.

OBJECTIVE: To genomically characterize Kpn-KPC-1, the first blaKPC-2-carrying Klebsiella pneumoniae isolate reported in Chile, and contextualize it within the global ST101 lineage. METHODS: Kpn-KPC-1 was analyzed by whole-genome sequencing. Its resistome, virulome, plasmid content, and blaKPC-2 genetic context were characterized, and 537 publicly available ST101 genomes were used for comparative phylogenomics. RESULTS: Kpn-KPC-1 belonged to ST101 and carried blaKPC-2 within the conventional Tn4401a transposon on a mosaic plasmid encoding multiple replication initiators and conjugation-associated genes. The isolate also harbored an OmpK36 porin alteration and accessory resistance- and virulence-associated determinants, including ICEKp3/ybt-9, K17, and O1αβ,2α. Phylogenomic analysis placed Kpn-KPC-1 within a predominantly European clade, closest to Italian isolates recovered between 2012 and 2018. The absence of additional Chilean ST101 isolates related to Kpn-KPC-1 supports limited local dissemination of this lineage. Globally, ST101 was enriched in carbapenemase genes, particularly blaOXA-48-like and blaKPC variants. CONCLUSIONS: Kpn-KPC-1 represents a transient introduction of a carbapenemase-prone, high-risk ST101 lineage rather than the founder of a locally disseminated clone in Chile. Genome-level analysis resolved the blaKPC-2 context in this historical isolate, linking the carbapenemase gene to Tn4401a on a mosaic multidrug-resistance plasmid within an imported ST101 background. These findings underscore the value of retrospective genomics for reconstructing early antimicrobial-resistance introduction events.

Carbapenem-resistant enterobacterales↗
PubMed2004

Basic fibroblast growth factor promotes the trans-differentiation of mouse bone marrow cells into hepatic lineage cells via multiple liver-enriched transcription factors.

BACKGROUND/AIMS: Evidence that bone marrow cells have trans-differentiating potential to hepatocytes has been described in recent reports. However, the molecular mechanism underlying this phenomenon is unclear. To address this issue, we investigated the parameters involved in the trans-differentiation of bone marrow cells into a hepatic lineage. METHODS: Mouse BM cells were cultured in a collagen gel without or with growth factors including basic fibroblast growth factor. The expression of hepatocyte-specific markers, cholangiocyte-specific marker and liver-enriched transcription factors was identified by RT-PCR and immunohistochemistry. RESULTS: Basic fibroblast growth factor was found to be the most effective for inducing albumin in cultured BM cells. Furthermore, on stimulation of basic fibroblast growth factor, BM cells were found to express other hepatocyte-specific markers and a cholangiocyte-specific marker. This conversion was found to be associated with the induction of transcription factors including hepatocyte nuclear factors and GATA family proteins. CONCLUSIONS: We established an in vitro culture system in which mouse bone marrow cells could trans-differentiate to hepatic lineage cells in response to growth factors, without cell fusion. In particular, basic fibroblast growth factor has the ability to induce the trans-differentiation into hepatic lineage cells from BM cells.

Albumins↗
PubMedDate not supplied

Influence of temperature preferences of two Paecilomyces fumosoroseus lineages on their co-infection pattern.

In order to clarify the epidemiological potential of entomopathogenic fungi for insect pest control, the role of the temperature as one environmental constraint was investigated on the pattern of co-infection of Galleria mellonella by two distinct lineages of a hyphomycete, Paecilomyces fumosoroseus. The distribution of conidial populations collected on cadavers of hosts co-infected under 20 regimes, ranging from 13 to 35 degrees C, was examined. The apparent temperature tolerance of both fungal isolates was related to their in vitro colony growth and their in vivo sporulation ability. The conidial populations were characterized by molecular markers based on restriction fragment length polymorphisms of the internal transcribed spacers (ITS-RFLP) and random amplified polymorphic DNA (RAPD) contrasting profiles in combination with the conidial size. This study allowed a different temperature profile was identified for each isolate. Under most temperature regimes, only one lineage prevailed upon the infected insect; whereas both lineages coexisted at 20-25 and 25-25 degrees C. When one haplotype dominated, the displacement of the other one depended on its temperature tolerance. These results suggest that more consideration should be given to population-genetics analyses for evaluating the adaptability of microbial control agents to targeted environments.

Animals↗
PubMed2006

Genetic Diversity of Microbial Eukaryotes in Anoxic Sediment of the Saline Meromictic Lake Namako-ike (Japan): On the Detection of Anaerobic or Anoxic-tolerant Lineages of Eukaryotes.

Available sequence data on eukaryotic small-subunit ribosomal DNA (SSU rDNA) directly retrieved from various environments have increased recently, and the diversity of microbial eukaryotes (protists) has been shown to be much greater than previously expected. However, the molecular information accumulated to date does still not thoroughly reveal ecological distribution patterns of microbial eukaryotes. In the ongoing challenge to detect anaerobic or anoxic-tolerant lineages of eukaryotes, we directly extracted DNA from the anoxic sediment of a saline meromictic lake, constructed genetic libraries of PCR-amplified SSU rDNA, and performed phylogenetic analyses with the cloned SSU rDNA sequences. Although a few sequences could not be confidently assigned to any major eukaryotic groups in the analyses and are debatable regarding their taxonomic positions, most sequences obtained have affiliations with known major lineages of eukaryotes (Cercozoa, Alveolata, Stramenopiles, and Opisthokonta). Among these sequences, some branched with lineages predominantly composed of uncultured environmental clones retrieved from other anoxic environments, while others were closely related to those of eukaryotic parasites (e.g. Phytomyxea of Cercozoa, Gregarinea of Alveolata, and Ichthyosporea of Opisthokonta).

Anaerobiosis↗
PubMed2005

Lineage differentiation of canine lymphoma/leukemias and aberrant expression of CD molecules.

Multiparameter flow cytometry analysis and specific cluster differentiation (CD) molecules were used to determine the expression profiles of B- and T-cell antigens on lymph node preparations from 59 dogs with generalized or multisystemic lymphoma. Lymph node samples from 11 healthy dogs were labeled to validate the specificity of antibodies and to formulate guidelines for interpretation of the results obtained from lymphoma samples. In normal lymph nodes, T-lymphocytes expressing CD3, CD4, or CD8 beta represented 59+/-11%, 43+/-8%, or 16+/-5% of the total cells, whereas B-lymphocytes expressing either CD21 or surface IgM (IgM) represented 37+/-9% or 14+/-5%, respectively. Small lymphocytes could be distinguished from large lymphocytes by forward light scatter. Of the patient samples 29 different breeds were represented with Golden and Labrador retriever being the most common. The lymphoma samples segregated into three groups based on CD antigen expression. Thirty cases predominantly expressed one or more combinations of CD79a, IgM, and CD21 representing a B-cell lineage. Three B-cell cases also expressed the stem cell antigen, CD34. Sixteen cases expressed one or more combinations of CD3, CD4, and CD8 consistent with a T-cell lineage and CD3+CD4+CD8--phenotype was the most common. Thirteen cases showed a mixed expression profile for T- and B-cell antigens and in three cases CD14 was highly expressed. Clinical response was poorest for T-cell lymphomas. Leukemic states occurred in all three phenotypes; but mixed cell cases had the greatest proportion. Dual immunofluorescence staining confirmed co-expression of T-cell (CD3) and B-cell antigens (CD79a or CD21) on neoplastic lymphocytes of six mixed cell cases. In one mixed cell case, dual immunostaining identified lymphocyte populations that stained mutually exclusive for CD79a and CD3. Six mixed cell lymphomas tested by PCR showed clonality for rearranged antigen receptor. Four cases that were CD79a+CD3+ had TCRgamma chain gene rearrangements, whereas two cases that were CD3+CD8+CD21+ had Ig heavy chain rearrangement. One case expressing multiple CD molecules (CD3+CD8+CD21+CD14+) was PCR negative for both Ig and TCRgamma gene rearrangement and could not be classified into a B- or T-cell lineage. We show for the first time co-expression of B- and T-cell markers on lymphoma cells that had specific T- or B-cell gene rearrangements. These findings suggest that aberrant CD molecule expression is not an uncommon finding in canine lymphomas and is a useful diagnostic marker for malignancy.

Animals↗
PubMed2005

Analysis of the matrix protein gene sequence of the Asian lineage of peste-des-petits ruminants vaccine virus.

The M gene nucleotide sequence of an Indian peste-des-petits ruminants (PPRV) vaccine virus ("PPRV Sungri/96") belonging to Asian lineage was determined. The gene is 1476 nucleotides long with a single open reading frame (ORF). The nucleotide and predicted amino acid sequence was compared with the homologous region of the African Lineage Vaccine virus "PPRV/Nigeria/75/1". The nucleotide sequence of the "PPRV Sungri/96" was 86% identical to that of "PPRV/Nigeria/75/1", while a homology of 93% and 95% could be observed in the ORF and amino acids level, respectively. The M gene encodes a protein of 335 amino acids, with a predicted molecular weight (MW) of 37.8 kDa. The ORF is flanked by a 3' untranslated region of 436 nucleotides and a high level of sequence divergence (approximately 30%) could be observed in this region between the vaccine viruses of Asian and African lineages. A high degree of conservation of several amino acids of this protein observed previously was also confirmed in this study.

Amino Acid Sequence↗
PubMed2006

Full-length sequence analysis of SIVmus in wild populations of mustached monkeys (Cercopithecus cephus) from Cameroon provides evidence for two co-circulating SIVmus lineages.

Mustached monkeys (Cercopithecus cephus), which form a significant component of primate bushmeat in west central Africa, are infected with simian immunodeficiency virus (SIVmus). We identified and genetically characterized five new SIVmus strains infecting wild living mustached monkeys from Cameroon. Phylogenetic analysis of partial pol sequences revealed that SIVmus strains form two distinct groups within the clade comprised of lentiviruses isolated from Cercopithecus nictitans (SIVgsn), Cercopithecus mona (SIVmon) and C. cephus (SIVmus). Characterisation of three full-length SIVmus genomes confirmed the presence of two distinct lineages infecting mustached monkeys. These two variants of SIVmus, here designated SIVmus-1 and SIVmus-2, were isolated from animals sharing habitats within the same geographic region. Phylogenetic analyses showed that the diversification of SIVmus, SIVgsn and SIVmon involved inter-lineage recombination, and suggested that one of the SIVmus lineages likely resulted from cross-species transmission and recombination involving SIVmus and an as yet uncharacterized SIV. These results indicate that cross-species transmission and recombination play a major role in the evolution of primate lentiviruses among sympatric primate species.

Animals↗
PubMed2007

Novel porcine rotavirus of genotype P[27] shares new phylogenetic lineage with G2 porcine rotavirus strain.

A novel and unusual strain of porcine rotavirus (PoRV) CMP034 was isolated from a 7-week-old piglet during the epidemiological survey of porcine rotavirus infection in Chiang Mai province, Thailand from June 2000 to July 2001. Molecular characterization of gene VP4 by sequence analysis showed a low level of amino acid sequence identity, ranging from 56.7% to 76.6%, while comparison of VP8* portion showed 41.8% to 69.9% identity, with the 26 P genotypes recognized to date. Phylogenetic analysis of the VP4 sequence revealed that CMP034 was only distantly related to the other 26 P genotypes and was located in a separate branch. Sequence analysis of gene VP7 showed the highest level of amino acid identity (94.7%) with the PoRV G2-like reference strain 34461-4 but a lower level of identity with those of human G2 rotaviruses, ranging from 87.7% to 88.0%. Phylogenetic analysis of gene VP7 revealed two major lineages among G2 rotavirus strains based on the host origin. PoRV strain CMP034 clustered exclusively with G2-like PoRV strain 34461-4 in a novel lineage that is distinct from the major G2 human lineage. Moreover, strain CMP034 displayed a porcine-like VP6 and NSP5/6 with subgroup I specificity, while bearing an NSP4 with some genetic group B human-like characteristics. These findings provide evidence that CMP034 should be considered as a novel VP4 genotype P[27].

Amino Acid Sequence↗