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PubMed2006

PpRT1: the first complete gypsy-like retrotransposon isolated in Pinus pinaster.

We have isolated and characterized a complete retrotransposon sequence, named PpRT1, from the genome of Pinus pinaster. PpRT1 is 5,966 bp long and is closely related to IFG7 gypsy retrotransposon from Pinus radiata. The long terminal repeats (LTRs) have 333 bp each and show a 5.4% sequence divergence between them. In addition to the characteristic polypurine tract (PPT) and the primer binding site (PBS), PpRT1 carries internal regions with homology to retroviral genes gag and pol. The pol region contains sequence motifs related to the enzymes protease, reverse transcriptase, RNAseH and integrase in the same typical order known for Ty3/gypsy-like retrotransposons. PpRT1 was extended from an EST database sequence indicating that its transcription is occurring in pine tissues. Southern blot analyses indicate however, that PpRT1 is present in a unique or a low number of copies in the P. pinaster genome. The differences in nucleotide sequence found between PpRT1 and IFG7 may explain the strikingly different copy number in the two pine species genome. Based on the homologies observed when comparing LTR region among different gypsy elements we propose that the highly conserved LTR regions may be useful to amplify other retrotransposon sequences of the same or close retrotransposon family.

Amino Acid Sequence↗

PubMed2004

TBP-associated factors in Arabidopsis.

Initiation of transcription mediated by RNA polymerase II requires a number of transcription factors among which TFIID is the major core promoter recognition factor. TFIID is composed of highly conserved factors which include the TATA-binding protein (TBP) and about 14 TBP-associated factors (TAFs). Since TAFs play important roles in transcription they have been extensively studied in organisms like yeast, Drosophila and human. Surprisingly, TAFs have been poorly characterized in plants. With the completion of the Arabidopsis genome sequence, it is possible to search for TAFs, since many of them have conserved amino acid sequences. Mining the genome of Arabidopsis for TAFs resulted in the identification of 18 putative Arabidopsis TAFs (AtTAFs). We have analyzed their protein structure and their genomic localisation. Expression profiling by RT-PCR showed that these TAFs are expressed in all parts of the plant which is in agreement with their general role in transcription. These analyses in combination with their evolutionary conservation with TAFs of other organisms are discussed.

Arabidopsis↗

PubMed2003

Analysis of the Candida albicans proteome. I. Strategies and applications.

The alarming incidence of invasive candidiasis, predominantly among the recent expanding immunocompromised population, the appearance of antifungal-drug resistance, and the lack of specific diagnostic tests for it have demanded more impactful research into Candida albicans pathogenicity. Proteomic approaches can provide accurate clues about its biological complexity. Indeed, initial C. albicans proteome analyses have focused on the understanding of dimorphism, host responses, the cell wall, virulence factors and drug resistance, among others. This review aims to briefly outline the technology available for proteomics-based studies, surveying the main proteomic approaches applied to C. albicans research. Prefractionation techniques, two-dimensional gel electrophoresis and mass spectrometry continue to be the backbone of proteomic projects. Emerging strategies for protein separation, quantification and identification may, however, challenge the pivotal position of 2D-PAGE. Regardless of this, since we are now approaching the completion and annotation of C. albicans genome sequencing, systematic characterization of the proteome of this fungal pathogen, although still in its early stages, heralds an exciting expansion of our knowledge in years to come.

Candida albicans↗

PubMed2003

Single-nucleotide polymorphisms in soybean.

Single-nucleotide polymorphisms (SNPs) provide an abundant source of DNA polymorphisms in a number of eukaryotic species. Information on the frequency, nature, and distribution of SNPs in plant genomes is limited. Thus, our objectives were (1) to determine SNP frequency in coding and noncoding soybean (Glycine max L. Merr.) DNA sequence amplified from genomic DNA using PCR primers designed to complete genes, cDNAs, and random genomic sequence; (2) to characterize haplotype variation in these sequences; and (3) to provide initial estimates of linkage disequilibrium (LD) in soybean. Approximately 28.7 kbp of coding sequence, 37.9 kbp of noncoding perigenic DNA, and 9.7 kbp of random noncoding genomic DNA were sequenced in each of 25 diverse soybean genotypes. Over the >76 kbp, mean nucleotide diversity expressed as Watterson's theta was 0.00097. Nucleotide diversity was 0.00053 and 0.00111 in coding and in noncoding perigenic DNA, respectively, lower than estimates in the autogamous model species Arabidopsis thaliana. Haplotype analysis of SNP-containing fragments revealed a deficiency of haplotypes vs. the number that would be anticipated at linkage equilibrium. In 49 fragments with three or more SNPs, five haplotypes were present in one fragment while four or less were present in the remaining 48, thereby supporting the suggestion of relatively limited genetic variation in cultivated soybean. Squared allele-frequency correlations (r(2)) among haplotypes at 54 loci with two or more SNPs indicated low genome-wide LD. The low level of LD and the limited haplotype diversity suggested that the genome of any given soybean accession is a mosaic of three or four haplotypes. To facilitate SNP discovery and the development of a transcript map, subsets of four to six diverse genotypes, whose sequence analysis would permit the discovery of at least 75% of all SNPs present in the 25 genotypes as well as 90% of the common (frequency >0.10) SNPs, were identified.

DNA Primers↗

PubMed2000

The human gastric colonizer Helicobacter pylori: a challenge for host-parasite glycobiology.

The Gram-negative bacterium Helicobacter pylori was first described in 1983 and currently represents one of the most active single research topics in biomedicine. It is specific for the human stomach and chronically colonizes a majority of the global population, which results in a symptom-free local inflammation. In 10-20% of carriers, gastroduodenal disease develops, including gastric or duodenal ulcer, and atrophic gastritis, which is a precondition to gastric cancer. A probable long coevolution of microbe and homo sapiens in a restricted niche has apparently generated a complex and sophisticated interplay. Access to complete bacterial genome sequences assists in a comparative functional characterization. A dynamic glycosylation of both microbe and host cells is of growing interest to analyze. Several glycoforms of bacterial surface lipopolysaccharides show advanced molecular mimicry of host epitopes and a distinct phase variation. An unusually large family of 32 outer membrane proteins probably reflects the complex interrelationship with the host. The unique diversity found for carbohydrate-binding specificities may be mediated by these surface proteins, of which the Lewis b-binding adhesin is the only known example so far, and these binding activities are subject to phase variation. The host mucosa glycosylation may also vary with different conditions, allowing a modulated crosstalk between microbe and host. The bacterium actively stimulates the host inflammatory response, apparently for nutritional purposes, and there is no evidence for a spontaneous elimination of the microbe. Colonization appears to be preventive for upper stomach and esophageal diseases. Current antibiotic treatment eradicates the microbe and cures ulcer disease. Alternative approaches must, however, be developed for a potential global prevention of disease.

Carbohydrate Sequence↗

PubMed1998

Identification and characterization of the Cydia pomonella granulovirus cathepsin and chitinase genes.

A 3.2 kb BamHI-EcoRI fragment of the Cydia pomonella granulovirus (CpGV) genome was subcloned and characterized. Sequence analysis revealed two complete and one partial open reading frames (ORFs). ORF7L is predicted to encode a 66.7 kDa protein (594 amino acid residues) that is 57% identical (amino acid sequence) to the chiA gene (ORF126) of Autographa californica nucleopolyhedrovirus (AcMNPV), encoding a chitinase. ORF8R is 333 amino acids in length and shows high similarity (between 64% and 67%) with baculovirus cathepsins. The partial ORF, ORF5L, is related to AcMNPV ORF145 of unknown function. Phylogenetic trees were constructed for both chitinase and cathepsin sequences from baculoviruses and other species. In both cases, the baculovirus sequences were monophyletic but with a deep division between the GVs and NPVs, suggesting both genes were present in an ancestral virus prior to the separation of the two genera. However, these studies did not provide definitive evidence for the origin of either protein in baculoviruses. To investigate CpGV cathepsin function, a rescue experiment was performed using a Bombyx mori NPV (BmNPV) mutant (BmCysPD) which lacks a functional cathepsin (cath) gene. Larvae infected with BmCysPD-Cp.cat, a BmCysPD derivative carrying CpGV cath, showed similar symptoms to wild-type BmNPV infected insects, confirming that CpGV cath encodes a functional cathepsin. Primer extension analysis of mRNA from BmCysPD-Cp.cat infected cells showed that CpGV cath transcription was initiated from a consensus late transcription motif (ATAAG) within the CpGV sequences, indicating that a CpGV late promoter motif was recognized in this NPV system.

Amino Acid Sequence↗

PubMed2002

Pseudomonas aeruginosa synthesizes phosphatidylcholine by use of the phosphatidylcholine synthase pathway.

Phosphatidylcholine (PC) is a ubiquitous membrane lipid in eukaryotes but has been found in only a limited number of prokaryotes. Both eukaryotes and prokaryotes synthesize PC by methylating phosphatidylethanolamine (PE) by use of a phospholipid methyltransferase (Pmt). Eukaryotes can synthesize PC by the activation of choline to form choline phosphate and then CDP-choline. The CDP-choline then condenses with diacylglycerol (DAG) to form PC. In contrast, prokaryotes condense choline directly with CDP-DAG by use of the enzyme PC synthase (Pcs). PmtA was the first enzyme identified in prokaryotes that catalyzes the synthesis of PC, and Pcs in Sinorhizobium meliloti was characterized. The completed release of the Pseudomonas aeruginosa PAO1 genomic sequence contains on open reading frame predicted to encode a protein that is highly homologous (35% identity, 54% similarity) to PmtA from Rhodobacter sphaeroides. Moreover, the P. aeruginosa PAO1 genome encodes a protein with significant homology (39% amino acid identity) to Pcs of S. meliloti. Both the pcs and pmtA homologues were cloned from PAO1, and homologous sequences were found in almost all of the P. aeruginosa strains examined. Although the pathway for synthesizing PC by use of Pcs is functional in P. aeruginosa, it does not appear that this organism uses the PmtA pathway for PC synthesis. We demonstrate that the PC synthesized by P. aeruginosa PAO1 localized to both the inner and outer membranes, where it is readily accessible to its periplasmic, PC-specific phospholipase D.

Amino Acid Sequence↗

PubMed1995

Duck hepatitis B virus integrations in LMH chicken hepatoma cells: identification and characterization of new episomally derived integrations.

While the cytoplasmic phase of the hepadnavirus replication cycle is well understood, very little is known about the nuclear phase. In contrast to retroviruses, proviral integration is not required for hepadnavirus replication; however, some of the viral DNAs in the nucleus are diverted into an integration pathway. Under certain conditions these integrations function as carcinogenic agents. In order to study the integration process, we have utilized LMH-D2 cells, which replicate wild-type duck hepatitis B virus (DHBV), to develop the first protocol to detect and characterize integrations of DHBV originating from episomal viral DNAs. Contrary to expectations, our results showed that stable new integrations are readily detectable in subclones of LMH-D2 cells. Complete characterization of one integration revealed a single-genome-length integrant with the structure of double-stranded linear (DSL) DHBV DNAs which are produced by in situ priming during viral replication. The integration contained a terminal redundancy of 6 bp from the r region of the virus DNA minus strand as well as a direct repeat of 70 bp of cellular DNA. On the basis of the structure of the integrant and the cellular DNA target site, we propose a molecular model for the integration mechanism that has some similarities to that of retroviruses. Identification of DSL hepadnavirus DNA integration suggests the possibility that modified DSL viral DNAs may be the precursors to a class of simple, unrearranged hepadnavirus integrations.

Animals↗

PubMed2025

Genomics insight on passion fruit viral disease complexity.

Passion fruit viral diseases pose a significant threat to Kenya's passion fruit industry. To unravel the complexity of these diseases, comprehensive virus surveys were conducted across major passion fruit-growing counties. Passion fruit woodiness disease symptoms, like fruit hardening, chlorotic mottling, and leaf distortion, were prevalent. The study unveiled the first 23 complete genomes of Ugandan passiflora virus (UPV) and two East Asian passiflora distortion virus (EAPDV) in Kenya. UPV showed 99% nucleotide (nt) match to a UPV genome from Uganda and 66% nt identity match to EAPDV. In addition, UPV variants and two partial passion fruit green spot virus sequences and partial (passiflora emaravirus) segment RNA1-5 (novel allexivirus and an emaravirus, respectively) were detected. Phylogenetic analysis revealed distinct lineages (I-III), indicating potential multiple introductions into Kenya. Recombination analysis detected no significant breakpoints. However, the study proposed the renaming of EAPDV to passiflora distortion virus (PDV) and UPV to passiflora virus (PV) for neutral nomenclature, without geographical association. Additionally, the study highlighted the role of coinfections in symptom expression, suggesting a potential synergistic relationship between PV, PDV, and other viruses. The results recommend stringent management strategies and enhanced surveillance to mitigate the economic impact of these viruses on the Kenyan passion fruit industry. The findings from this study underscore the need to strengthen nursery certification programs and pest diagnostic protocols in Kenya. Additionally, enhanced pest surveillance and import regulations are critical to preventing the introduction and spread of emerging plant viral diseases, thereby safeguarding the country's horticultural productivity and biosecurity. To our knowledge, this is the first comprehensive study of viral diseases of passion fruit in Kenya.IMPORTANCEThis study presents the first comprehensive survey of viral pathogens affecting passion fruit in Kenya, identifying Ugandan passiflora virus (UPV) and East Asian passiflora distortion virus (EAPDV) as major contributors. Through genomic sequencing, 23 complete genomes of UPV and two of EAPDV were characterized, revealing a 99% nucleotide (nt) similarity between UPV strains from Uganda and Kenya, and 66% nt match with EAPDV. Phylogenetic analysis identified distinct lineages, suggesting possible multiple viral introductions in Kenya. The study also highlights potential synergistic coinfections between UPV, EAPDV, and other viruses, leading to more severe disease symptoms. In light of these findings, the study proposes renaming EAPDV as passiflora distortion virus and UPV as passiflora virus for a more neutral name classification. The research underscores the urgent need for enhanced surveillance, stringent phytosanitary measures, and improved management strategies to mitigate the threat of viral diseases, to safeguard the Kenyan passion fruit industry, and elsewhere.

Plant Diseases↗

PubMed2026

Mitochondrial genomes of Dactylogyrus wunderi (Monopisthocotyla: Dactylogyridae): structural features, codon usage patterns, and phylogenetic implications.

BACKGROUND: Codon usage bias (CUB) is a common phenomenon reported among many species and genes, but its unique characteristics in the mitochondrial genome of class Monopisthocotyla remain unknown. METHODS: The complete mitochondrial genome of Dactylogyrus wunderi was sequenced and characterized, and the mitochondrial genome compositions and CUB of six Dactylogyrus species and 35 Monopisthocotyla species were analyzed using bioinformatics methods. RESULTS: The mitochondrial genome of D. wunderi is a typical circular structure in length of 14,920 bp. The A + T contents of the six Dactylogyrus species (58.4% ± 5.7%) were significantly lower than that of Monopisthocotyla species (71.0% ± 5.80%, p < 0.01). Neutrality plot analysis showed slopes of 0.3136 and 0.389 in the six Dactylogyrus and the 35 Monopisthocotyla species, respectively. Furthermore, 98.3% and 77.4% of the genes in the six Dactylogyrus and the Monopisthocotyla species, respectively, had effective number of codons (ENC) higher than 35, but 23.3% and 0.5% genes of ENC ratio ranged from - 0.05 to 0.05 in the six Dactylogyrus and Monopisthocotyla species. Phylogenetic analysis revealed that, within the context of the sampled taxa, the families of Monopisthocotyla were monophyletic groups, except for Ancyrocephalidae. CONCLUSIONS: The nucleotide composition had AT base bias in Monopisthocotyla, and natural selection was the main factor affecting CUB in the mitochondrial genomes of Monopisthocotyla species. These results provided insights into the factors affecting CUB in Monopisthocotyla species and deepened our insight of phylogeny, evolution, and codon usage of Monopisthocotyla.

Genome, Mitochondrial↗

PubMed2025

Molecular Characterization and Epidemiology of Human Noroviruses in the Sverdlovsk Region, Russian Federation.

Human noroviruses (HuNoVs) stand as the primary cause of acute viral gastroenteritis outbreaks worldwide, particularly impacting children under the age of five. In Russia, reports of norovirus gastroenteritis have surged, especially in the post-COVID-19 era starting in 2022, with elevated infection rates reported into 2024. These viruses exhibit significant mutational variability, leading to the emergence of recombinant strains that can evade immune responses. A comprehensive examination of the complete genome is crucial for understanding the evolution of norovirus genes and for predicting potential outbreaks. This research focuses on analyzing the genotypic composition of HuNoVs circulating in the Sverdlovsk region during 2024, using Sanger sequencing and next-generation sequencing (NGS). Biological samples were collected (n = 384) from patients diagnosed with norovirus infection within the region. Bioinformatics analysis targeted the nucleotide sequences of the ORF1/ORF2 fragment and the assembly of complete genomes for the GII.4 and GII.7 genotypes. In total, 220 HuNoVs were characterized, representing 57.3% of the collected samples. The main capsid variants forming the predominant genotypic profile included GII.4 (n = 88, 40%), GII.7 (n = 86, 39%), and GII.17 (n = 14, 6%). Using NGS, we successfully assembled 8 out of 10 complete genomes for noroviruses GII.4[P16] and GII.7[P7]. Non-synonymous substitutions appeared at amino acid sites corresponding to the subdomains of VP1 in these strains. This molecular-genetic analysis provides contemporary insights into the genotypic composition, circulation patterns, and evolutionary dynamics associated with the dominant genovariants GII.4[P16] and GII.7[P7].

Norovirus↗

PubMed2007

Characterization of the mitochondrial genome of Diphyllobothrium latum (Cestoda: Pseudophyllidea) - implications for the phylogeny of eucestodes.

The complete nucleotide sequence of the mitochondrial genome was determined for the fish tapeworm Diphyllobothrium latum. This genome is 13,608 bp in length and encodes 12 protein-coding genes (but lacks the atp8), 22 transfer RNA (tRNA) and 2 ribosomal RNA (rRNA) genes, corresponding to the gene complement found thus far in other flatworm mitochondrial (mt) DNAs. The gene arrangement of this pseudophyllidean cestode is the same as the 6 cyclophyllidean cestodes characterized to date, with only minor variation in structure among these other genomes; the relative position of trnS2 and trnL1 is switched in Hymenolepis diminuta. Phylogenetic analyses of the concatenated amino acid sequences for 12 protein-coding genes of all complete cestode mtDNAs confirmed taxonomic and previous phylogenetic assessments, with D. latum being a sister taxon to the cyclophyllideans. High nodal support and phylogenetic congruence between different methods suggest that mt genomes may be of utility in resolving ordinal relationships within the cestodes. All species of Diphyllobothrium infect fish-eating vertebrates, and D. latum commonly infects humans through the ingestion of raw, poorly cooked or pickled fish. The complete mitochondrial genome provides a wealth of genetic markers which could be useful for identifying different life-cycle stages and for investigating their population genetics, ecology and epidemiology.

Animals↗

PubMed1998

Molecular cloning, gene structure and expression profile of mouse C1 inhibitor.

The gene encoding C1 inhibitor, the major control element of activation of the classical pathway of complement and a major inhibitor of several plasma serine proteases, has been studied only in man, where deficiency of C1 inhibitor results in the dominantly transmitted disease hereditary angioedema. Full-length mouse C1 inhibitor cDNA and genomic clones were isolated and characterized as a first step towards the complete characterization of the pattern of C1 inhibitor expression and the production of an animal model of C1 inhibitor deficiency. Restriction-enzyme and sequence analyses of a full-length genomic clone demonstrated that the mouse gene has the same structure as the human homologue, but differs in size (9 kb versus 17 kb), mostly due to the presence of repetitive Alu elements in the human gene. Sequence comparisons in the promoter region indicate important similarities, i.e. the absence of a TATA box, the presence of an initiator sequence encompassing the transcription-start site and of a gamma-interferon-activated sequence (GAS) element at position -124 of the human sequence. A stretch of about 100 nucleotides in intron 1 reveals an unusually high degree of conservation for non-coding sequences and contains non-canonical but conserved tandemly arranged GAS elements at positions 369 and 388 of the human sequence. This finding supports the conclusions of functional studies on the human C1INH gene indicating a role of this region in modulation of transcription by interferons. The profile of C1 inhibitor expression in mouse liver, lung, heart, kidney, spleen and brain was determined by quantitative northern blot analysis.

Animals↗

PubMed2006

Cloning and characterization of the HSP70 Gene, and its expression in response to diapauses and thermal stress in the onion maggot, Delia antiqua.

The cytosolic members of the HSP70 family of proteins play key roles in the molecular chaperone machinery of the cell. In the study we cloned and sequenced the fulllength cDNA of Delia antiqua HSP70 gene, which is 2461 bp long and encodes 643 a.a. with a calculated molecular mass of 70,787 Da. We investigated gene copies of cytosolic HSP70 members of 4 insect species with complete genome available, and found that they are quite variable with species. In order to characterize this protein we carried out an alignment and a phylogenetic analysis with 41 complete protein sequences from insects. The analysis divided the cytosolic members of the family into two classes, HSP70 and HSC70, distinguishable on the basis of 15 residues. HSP70 class members were slightly shorter in length and smaller in molecular mass relative to the HSC70 class members, and the conservative and functional regions in these sequences were documented. Mainly, we investigated the expression of Delia antiqua HSP70 gene, in response to diapauses and thermal stresses. Both summer and winter diapauses elevated HSP70 transcript levels. Cold-stress led to increased HSP70 expression levels in summer- and winter-diapausing pupae, but heat-stress elevated the levels only in the winter-diapausing pupae. In all cases, the expression levels, after being elevated, gradually decreased with time. HSP70 expression was low in non-diapausing pupae but was up-regulated following cold- and heatstresses. Heat-stress gradually increased the mRNA level with time whereas cold-stress gradually decreased levels after an initial increase.

Amino Acid Sequence↗

PubMed2006

Comparative genomics and experimental characterization of N-acetylglucosamine utilization pathway of Shewanella oneidensis.

We used a comparative genomics approach implemented in the SEED annotation environment to reconstruct the chitin and GlcNAc utilization subsystem and regulatory network in most proteobacteria, including 11 species of Shewanella with completely sequenced genomes. Comparative analysis of candidate regulatory sites allowed us to characterize three different GlcNAc-specific regulons, NagC, NagR, and NagQ, in various proteobacteria and to tentatively assign a number of novel genes with specific functional roles, in particular new GlcNAc-related transport systems, to this subsystem. Genes SO3506 and SO3507, originally annotated as hypothetical in Shewanella oneidensis MR-1, were suggested to encode novel variants of GlcN-6-P deaminase and GlcNAc kinase, respectively. Reconstitution of the GlcNAc catabolic pathway in vitro using these purified recombinant proteins and GlcNAc-6-P deacetylase (SO3505) validated the entire pathway. Kinetic characterization of GlcN-6-P deaminase demonstrated that it is the subject of allosteric activation by GlcNAc-6-P. Consistent with genomic data, all tested Shewanella strains except S. frigidimarina, which lacked representative genes for the GlcNAc metabolism, were capable of utilizing GlcNAc as the sole source of carbon and energy. This study expands the range of carbon substrates utilized by Shewanella spp., unambiguously identifies several genes involved in chitin metabolism, and describes a novel variant of the classical three-step biochemical conversion of GlcNAc to fructose 6-phosphate first described in Escherichia coli.

Acetylglucosamine↗

PubMed2006

Toward a global picture of development: lessons from genome-scale analysis in Caenorhabditis elegans embryonic development.

Development is the result of complex events, including cascades of transcriptional programs and numerous molecular interactions. Traditionally, research focus has been given to the characterization of individual mutants, regulators, or interactions. With the availability of complete genome sequences and high-throughput (HT) experimental techniques, probing development on a system level has become feasible. Pioneering work initiated in invertebrate model systems such as Caenorhabditis elegans has provided first drafts of catalogs of essential components, transcriptional regulatory diagrams and molecular interaction networks underlying developmental processes. Integrating these drafts approximates a system-level picture of development and provides local models for protein/gene functions. Here we summarize the progress toward elucidating developmental processes on a system level, including the applications of genomic technologies and computational analyses. We discuss C. elegans embryonic development in case studies to illustrate how various HT approaches can be integrated and how biological insights can be gained from these approaches.

Animals↗

PubMed2003

Avermectin: biochemical and molecular basis of its biosynthesis and regulation.

Avermectin and its analogues, produced by Streptomyces avermitilis, are major commercial antiparasitic agents in the field of animal health, agriculture, and human infections. They are 16-membered pentacyclic lactone compounds derived from polyketide and linked to a disaccharide of the methylated deoxysugar l-oleandrose. Labeling studies, analyses of the biosynthetically blocked mutants, and the identification of the avermectin gene cluster allows characterization of most of the biosynthetic pathway. Recent completion of S. avermitilis genome sequencing is also expected to help in revealing the precise biosynthetic sequence and the complicated regulatory mechanism for avermectin biosynthesis, which has been long-awaited to be elucidated. The well characterized avermectin biosynthetic pathway and availability of S. avermitilis genome information in combination with the recent development of combinatorial biosynthesis should allow us to redesign more potent avermectin analogues and to engineer S. avermitilis as a more efficient host for the production of important commercial analogues.

Antiparasitic Agents↗

PubMedDate not supplied

Molecular characterization of a cloned dolphin mitochondrial genome.

DNA clones have been isolated that span the complete mitochondrial (mt) genome of the dolphin, Cephalorhynchus commersonii. Hybridization experiments with purified primate mtDNA probes have established that there is close resemblance in the general organization of the dolphin mt genome and the terrestrial mammalian mt genomes. Sequences covering 2381 bp of the dolphin mt genome from the major noncoding region, three tRNA genes, and parts of the genes encoding cytochrome b, NADH dehydrogenase subunit 3 (ND3), and 16S rRNA have been compared with corresponding regions from other mammalian genomes. There is a general tendency throughout the sequenced regions for greater similarity between dolphin and bovine mt genomes than between dolphin and rodent or human mt genomes.

Animals↗