Molecular phylogeny of Neocalanus copepods in the subarctic Pacific Ocean, with notes on non-geographical genetic variations for Neocalanus cristatus

Monophylies of Neocalanus cristatus, Neocalanus plumchrus andNeocalanus flemingeri were revealed by nucleotide sequencesof mitochondrial 16S rRNA gene (410 bp) but not of nuclear 18SrDNA gene (1802 bp). Intraspecific variations in mitochondrial16S rRNA of N. cristatus collected from geographically distantregions were very low (<0.5%).     

Comparison of Molecular Cytogenetic and Genetic Analyses in Accessions of the Two Biotypes of Vicia benghalensis L.

InVicia benghalensis two different biotypes, named A and B,had been observed which differed for several cytological, geneticaland biochemical characters. In the present study 27 accessionsof this species belonging to the two biotypes were investigatedusing different molecular analyses, supported by an attemptto produce hybrids between selected accessions. RAPD fingerprintingof the 27 accessions demonstrated that accessions belongingto biotype A show a high degree of genetic similarity, whilethe opposite is true for the accessions of biotype B. The totalgenomic DNA from one reference accession was used as a probeto Southern blots of the DNA extracted from all the accessionsin use. This analysis demonstrated that cross hybridizationamong the DNA of the two biotypes occurs only to a limited extent.The chromosomal localization of 18S-5.8S-25S and 5S rRNA geneclusters was determined byin situ hybridization. The resultsindicate that the two biotypes differ in the position of oneof the 5S rRNA gene clusters. This indicates a major chromosomalrearrangement. Cell synchronization experiments on two referenceaccessions suggested that the two biotypes might differ in theduration of the single phases of the cell cycle. Finally, incrossing experiments three pods were obtained which developedfor only a few days and proved to bear no viable seeds. Theseresults confirm the existence of two divergent gene-pools anddemonstrate the reproductive barrier between the two biotypes,thus suggesting the possibility of a specific ranking. Vicia benghalensis L.; genetic differentiation; in situ hybridization; Southern hybridization; crosses; RAPDs; cell synchronization     

A New Species of Scutellospora with a Coiled Germination Shield

During a survey of mycorrhizal fungi on the upper part of theCisadane River, on the slopes of Mount Pangrango in Gede PangrangoNational Park, West Java, an undescribed species of Scutellospora(Glomales)was discovered. This species has metallic golden to yellow toyellowish-brown spores that possess columnar protuberances.It is described and named Scutellospora projecturata sp. nov.The sequence of the nearly complete SSU rRNA gene was analysedand phylogenetic trees constructed. Copyright 2000 Annals ofBotany Company Scutellospora projecturata, Glomales, new species, 18s SSU rRNA, West Java, phylogenetic tree, phylogeny, arbuscular mycorrhizal fungi, AMF     

Molecular phylogeny of mangrove oysters (Crassostrea) from Brazil

As a result of phenotypic plasticity, the cupped oysters (Crassostrea)are difficult to identify by means of their morphology. However,molecular DNA markers are a useful means of discriminating amongthese species. Cupped oysters are one of the most widely culturedmarine invertebrates and correct species identification is importantin aquaculture. Moreover, the molecular phylogeny of the genusCrassostrea and the subfamily Crassostreinae is still not clear.In order to identify the Brazilian cupped oysters and to clarifythe phylogenetic relationships of these species, we sequenceda fragment of mitochondrial DNA (16S rRNA gene) from 120 specimenscollected at nine different sites distributed along the Braziliancoast. The results identified two native species of oyster:Crassostrea gasar, from the Amazon to the Parnaíba delta;and Crassostrea rhizophorae, from the northeast (Fortim) tothe south of Brazil. An exotic Crassostrea species, closelyrelated to Indo-Pacific Crassostrea, was found in one locationin the north of Brazil. Crassostrea showed monophyly and theAtlantic oysters are clearly separated from the Indo-Pacificcluster. (Received 30 May 2006; accepted 12 April 2007)     

Population genetics of drifting (Calanus spp.) and resident (Acartia clausi) plankton in Norwegian fjords

Kaartvedt distinguished between drifting and resident planktonand hypothesized that the latter were distinguished by theirability to maintain their horizontal position in desired habitats(Kaartvedt, 1993). In this study, we examined the populationgenetic consequences of these two lifestyles for copepods infour fjords of western Norway (Lurefjorden, Masfjorden, Sognefjordenand Sørfjorden) and one fjord in eastern Norway (Oslofjorden).Based on DNA sequence variation of a region of mitochondrial16S rRNA, we contrasted population genetic diversity and structurein drifting populations of Calanus spp. with that of residentpopulations of Acartia clausi. With the exception of Sørfjorden(where Calanus spp. were rare), two or three species of Calanusco-occurred in significantly different proportions in the fjords.Based on a 350 base-pair region of mitochondrial 16S rRNA, Calanusspp. varied in molecular genetic diversity, with the highestvalues for C.helgolandicus. There was no evidence of significantgenetic structure of fjord populations for either C.finmarchicusor C.helgolandicus; the population structure of C.glacialiscould not be evaluated as the species was only abundant in Lurefjorden.Acartia clausi was abundant in all five fjords sampled for thisstudy. Molecular genetic diversity of A.clausi, based on a 220bp region of mt 16S rRNA, was within the range of Calanus spp.values. Populations of A.clausi showed significant genetic structure(i.e. haplotype frequencies differed markedly) among the fjords.The results of this study indicated that little exchange (geneflow) occurs between populations of A.clausi in different fjords,and suggested that the populations are long-term residents ofa fjord. In contrast, most Calanus spp. fjord populations maybe replaced periodically, as they drift with currents flowingto and from coastal and fjord environments.     

Development, growth and egg production of the two copepod species Centropages hamatus and Centropages typicus in the laboratory

Laboratory experiments were set up in order to determine andcompare developmental rates, growth rates, generation timesand egg production rates for the two calanoid copepod speciesCentropages typicus and Centropages hamatus. The nauplii showeda higher developmental rate than the copepodites for both specieswith quite different individual stage durations, which gaveno indication of isochronal development. For C typicus equiproportionaldevelopment was found. The growth rates were exponential andhighest for the largest species C typicus, and for both speciesthe juvenile growth rates were very similar to the egg productionrates of the adults.     

Larval and early post-larval stages in the abbreviated development of Heterosquilla tricarinata (Claus, 1871) (Crustacea, Stomatopoda)

Heterosquilla tricarinata was laboratory-cultured through itscomplete larval development and found to have one propelagicand two pelagic larval stages prior to metamorphosis to thejuvenile. These larval stages, the first juvenile, and relevantportions of the second juvenile stage, are described and figured.Individual larvae do not change in size during intermoult periods.Larvae occurring in the plankton show a progressive decreasein mean size between early (September) and late (November) springtime.Reasons for this are suggested. The first pelagic stage of H.tricarinata is anatomically very advanced in development, andthe number of pelagic stages very few, in comparison with otherknown stomatopod life-histories. Ecological implications ofthis are discussed in relation to the high-latitude distributionof the species. Comparison is made between the final pelagicstage of H. tricarinata and that of its congenor H. brazieri. ^*Permanent address: Zoology Department, University of Queensland,Brisbane, Australia     

Characterization and physical mapping of ribosomal RNA gene families in Plantago

• Background and Aims The organization of rRNA genes incultivated Plantago ovata Forsk. and several of its wild allieswas analysed to gain insight into the phylogenetic relationshipsof these species in the genus which includes some 200 species. • Methods Specific primers were designed to amplify theinternal transcribed spacer (ITS1 and ITS2) regions from sevenPlantago species and the resulting fragments were cloned andsequenced. Similarly, using specific primers, the 5S rRNA genesfrom these species were amplified and subsequently cloned. Fluorescencein-situ hybridization (FISH) was used for physical mapping of5S and 45S ribosomal RNA genes. • Results The ITS1 region is 19–29 bp longer thanthe ITS2 in different Plantago species. The 5S rRNA gene-repeatingunit varies in length from 289 to 581 bp. Coding regions arehighly conserved across species, but the non-transcribed spacers(NTS) do not match any database sequences. The clone from thecultivated species P. ovata was used for physical mapping ofthese genes by FISH. Four species have one FISH site while threehave two FISH sites. In P. lanceolata and P. rhodosperma, the5S and 45S (18S-5·8S-25S) sites are coupled. • Conclusions Characterization of 5S and 45S rRNA geneshas indicated a possible origin of P. ovata, the only cultivatedspecies of the genus and also the only species with x = 4, froma species belonging to subgenus Psyllium. Based on the studiesreported here, P. ovata is closest to P. arenaria, althoughon the basis of other data the two species have been placedin different subgenera. FISH mapping can be used as an efficienttool to help determine phylogenetic relationships in the genusPlantago and show the interrelationship between P. lanceolataand P. lagopus.     

Ribosomal RNA gene dosage as a function of tissue and age for mouse and human.

The average number of rRNA genes per haploid genome (rRNA gene dosage) of the cells present in liver and brain was determined throughout the lifespan of the inbred C57BL/6J mouse strain and of human. Ribosomal RNA gene dosage was determined using the RNA-excess DNA - RNA hybridization technique. DNA was extracted and purified using a CsCl/chloroform method with a high percent yield (over 90%) to minimize any possible effects of tissue and age-dependent selective loss or gain of rRNA genes. Radioactive rRNA was from the liver of the youngest age group for either mouse or human in all hybridization experiments, with DNA from the different tissues and age groups being the only variable. In the young mouse (35-49 days), the rRNA gene dosage was 36% higher in brain (114 genes), as compared to liver (84 genes). The rRNA gene dosage remained essentially constant as a function of age for mouse brain; but between the age of about 220 to 440 days, it increased in liver, attaining approximately an equal value to that of brain. No significant difference was found in the rRNA gene dosage of brain or liver between different mice of the same age. In contrast to this result, a significant difference was found between human tissues of similar age. The rRNA gene dosage ranged about 2-fold (148-289) between 2 months to 75 years of age. An age-dependent trend, similar to that for mouse liver, was found when the averages of four different age groups totaling 20 individuals were compared. However, this was not statistically significant. No difference in the rRNA gene dosage as a function of sex or tissue was apparent. Several models are discussed to account for these results.     

Systematic Sequencing of the 180 Kilobase Region of the Bacillus Subtilis Chromosome Containing the Replication Origin

We have determined a 180 kb contiguous sequence in the replicationorigin region of the Bacillus subtilis chromosome. Open readingframes (ORF) in this region were unambiguously identified fromthe determined sequence, using criteria characteristic for theB. subtilis gene structure, i.e., starting with an ATG, GTGor TTG codon preceded by sequences complementary to the 3' endof the 16S rRNA. Four rRNA gene sets, 7 individual tRNA genesand 1 scRNA gene were identified, occupying 20 kb in total.In the remaining 160 kb region, 158 ORFs were identified, suggestingthat 1 ORF is coded on average by 1 kb of DNA of the B. subtilisgenome. Among the 158 ORFs, the functions of 48 ORFs were assignedand those of 11 ORFs are suggested through significant similaritiesto known proteins present in data banks. However, the functionsof more than half of the ORFs (63%) remain to be determined.     

中国部分地区柑桔木虱体内感染Wolbachia的检测及其系统发育分析

Wolbachia是一种广泛分布于节肢动物体内的共生细菌, 该共生菌经寄主卵的细胞质传播并参与多种寄主生殖活动调控, 对节肢动物的物种进化有着重要意义并可能应用于害虫的生物防治。本研究以柑桔黄龙病（Huanglongbing, HLB）的主要传播媒介——柑桔木虱Diaphorina citri为研究对象, 通过Wolbachia的16S rDNA、 细胞分裂基因（ftsZ）、 表面蛋白基因（wsp）的特异引物对来自于中国广西北海、 广西柳州、 广东深圳、 广东阳春、 福建福州5个地区的柑桔木虱进行PCR扩增, 并对扩增产物进行克隆测序, 与GenBank中相关序列进行比对分析, 建立了柑桔木虱共生Wolbachia的系统发育树。结果显示上述5个地区的柑桔木虱均存在Wolbachia感染, 通过Wolbachia的16S rDNA, ftsZ基因和wsp基因DNA序列的系统发育分析表明, 5个地区的柑桔木虱体内的Wolbachia均属于B组; 基于wsp基因的系统发育分析进一步表明5个地区的亚洲柑桔木虱体内的Wolbachia属于B组的Con亚组, 且不同地区柑桔木虱体内的Wolbachia的16S rDNA, ftsZ基因和wsp基因序列差异不明显。研究结果为认识柑桔黄龙病传播媒介昆虫的进化及其综合防治提供了重要的参考依据。     

Uptake of DOM by Nemertean Worms: Association of Worms with Arthrodial Membranes

SYNOPSIS. Carcinonemertes errans is a nemertean worm, the juvenilesof which are found as epibionts on the Dungeness crab, Cancermagister, in close association with the arthrodial membranesof the crabs. The juvenile nemerteans appear to have no meansof taking in particulate food but survive for many months onthe surface of the host. We show that the juvenile C. erransare capable of removing amino acids from dilute solution insea water, that the water near the arthrodial membranes wherethe worms are found contains high concentrations of primaryamines, and that there is a low resistance pathway for low molecularweight amino acids across the arthrodial membrane examined invitro.     

Vectorial transport of toxins from the dinoflagellate Gymnodinium breve through copepods to fish

Toxins from the dinoflagellate Gymnodinium breve were tracedthrough experimental food chains from dinoflagellates, throughcopepod grazers, to juvenile fish. The generality of this foodweb transfer was demonstrated using three different combinationsof copepods and juvenile fish during different seasons. Fishwere not exposed directly to the toxic dinoflagellates but werefed toxin-laden copepods in order to examine sublethal vectorialintoxication. Toxins were shown to move from fish viscera tomuscle tissue within periods of 2–6 h to 25 h. A new toxindetection method was used in this first stepwise demonstrationof multi-trophic-level intoxication of a planktonic food chainby G.breve. Micellar electrokinetic capillary electrophoresiswith laser-induced fluorescence allowed measurements of toxinsat trace levels and nanoliter-sized volumes critical for planktonicfood web transfer studies.     

Biochemical properties of nucleic acids of chloroplasts in Spirogyra1

In chloroplasts and nuclei of Spirogyra separated by discontinuoussucrose dnesity gradient centrifugation, five types of nucleicacids were found by MAK column chromatography; tRNA, low molecularweight rRNA, DNA, light and heavy rRNAs. Chloroplast rRNA was found to differ from cytoplasmic rRNA,by comparative studies on its base composition, its elutionpattern by MAK column chromatography and its sedimentation profilewith sucrose density gradient centrifugation. Molecular species of chloroplast DNA differed from those ofnuclear DNA in their thermal denaturation points (Tm), theirbehaviour on an IRC-50 column, their buoyant density in CsCland their base analyses. (Received September 13, 1972; )     

Instar-specific mortalities of coexisting Daphnia species in relation to food and invertebrate predation

Instar-specific mortalities of Daphnia hyalina and D.cucullatawere studied from May 19 to September 29, 1988 in combinationwith invertebrate predator and phytoplankton abundance. Simultaneouslife-table experiments were conducted under semi-natural conditionsin the laboratory to estimate juvenile mortality in a predator-freeenvironment. Juvenile mortality by predation was calculatedas the difference between juvenile mortality in the field andin the experiments and was the most important factor for thedifferences in abundance of the two species. For D.hyalina juvenilemortality was higher in early summer and probably caused byselective predation by Chaoborus flavicans. Predation by Leptodorakindtii was probably more important during the rest of the summer.Estimated mortality by predation adequately explained juvenilemortality, except for a 3-week period in August. Decreasingflagellate densities in July were accompanied by increased juvenilemortalities of D.hyalina and D.cucullata in the life-table experimentsin August and coincided with a Daphnia population decrease.     

重组保幼激素酯酶的纯化和生物学效应

培养昆虫细胞生产重组昆虫保幼激素酯酶时细胞培养液的蛋白质浓度为153.2～188.0 μg/mL。批量处理纯化重组保幼激素酯酶时酶蛋白活力回收率33%,效果与梯度分离方法相当,但简便快速,可作为大量分离纯化的第一步。重组保幼激素酯酶对烟草天蛾Manduca sexta幼虫的生物学活性测定结果验证了重组保幼激素酯酶对烟草天蛾幼虫和自身天然酶有相似的生物学活性。     

A Broad-Host-Range, Generalized Transducing Phage (SN-T) Acquires 16S rRNA Genes from Different Genera of Bacteria

Genomic analysis has revealed heterogeneity among bacterial 16S rRNA gene sequences within a single species; yet the cause(s) remains uncertain. Generalized transducing bacteriophages have recently gained recognition for their abundance as well as their ability to affect lateral gene transfer and to harbor bacterial 16S rRNA gene sequences. Here, we demonstrate the ability of broad-host-range, generalized transducing phages to acquire 16S rRNA genes and gene sequences. Using PCR and primers specific to conserved regions of the 16S rRNA gene, we have found that generalized transducing phages (D3112, UT1, and SN-T), but not specialized transducing phages (D3), acquired entire bacterial 16S rRNA genes. Furthermore, we show that the broad-host-range, generalized transducing phage SN-T is capable of acquiring the 16S rRNA gene from two different genera: Sphaerotilus natans, the host from which SN-T was originally isolated, and Pseudomonas aeruginosa. In sequential infections, SN-T harbored only 16S rRNA gene sequences of the final host as determined by restriction fragment length polymorphism analysis. The frequency of 16S rRNA gene sequences in SN-T populations was determined to be 1 × 10⁻⁹ transductants/PFU. Our findings further implicate transduction in the horizontal transfer of 16S rRNA genes between different species or genera of bacteria.     

Four TFL1/CEN-Like Genes on Distinct Linkage Groups Show Different Expression Patterns to Regulate Vegetative and Reproductive Development in Apple (Malusxdomestica Borkh.)

Recent molecular analyses in several plant species revealedthat TERMINAL FLOWER1 (TFL1) and CENTRORADIALIS (CEN) homologsare involved in regulating the flowering time and/or maintainingthe inflorescence meristem. In apple (Malusxdomestica Borkh.),four TFL1/CEN-like genes, MdTFL1, MdTFL1a, MdCENa and MdCENb,were found and mapped by a similar position on putatively homoeologouslinkage groups. Apple TFL1/CEN-like genes functioned equivalentlyto TFL1 when expressed constitutively in transgenic Arabidopsisplants, suggesting that they have a potential to complementthe TFL1 function. Because MdTFL1 and MdTFL1a were expressedin the vegetative tissues in both the adult and juvenile phases,they could function redundantly as a flowering repressor anda regulator of vegetative meristem identity. On the other hand,MdCENa was mainly expressed in fruit receptacles, cultured tissuesand roots, suggesting that it is involved in the developmentof proliferating tissues but not in the control of the transitionfrom the juvenile to the adult phase. In contrast, MdCENb wassilenced in most organs probably due to gene duplication bythe polyploid origin of apple. The expression patterns of MdTFL1and MdCENa in apple were also supported by the heterologousexpression of β-glucuronidase fused with their promoterregions in transgenic Arabidopsis. Our results suggest thatfunctional divergence of the roles in the regulation of vegetativemeristem identity may have occurred among four TFL1/CEN-likegenes during evolution in apple.