Identification of Saint Louis encephalitis virus mRNA.

Saint Louis encephalitis (SLE) virus-specific RNA was recovered from infected HeLa cells by sodium dodecyl sulfate (SDS)-phenol-chloroform extraction, and the molecular species were resolved by SDS-sucrose gradient centrifugation and agarose gel electrophoresis. Sucrose gradient centrifugation revealed the presence of a 45S species, minor 20 to 30S heterogeneous species, and an 8 to 10 S RNA species in the cytoplasmic extract. Analysis of the same samples by electrophoresis on agarose gels, under both nondenaturing and denaturing conditions, revealed only two virus-specific RNA molecules, the 45S genome-sized RNA and an 8 to 10S species. Varying the gel concentration to facilitate analysis of nucleic acids with molecular weights ranging from 25,000 to 25 X 10(6) failed to reveal additional RNA species, although low levels of a putative double-stranded replicative form could conceivably have escaped detection. From our observations it appears that the heterogeneous RNA species and presumably the 20S RNase-resistant species reported in other investigations of flavivirus RNA are degradation products or conformers of the 45S molecule. Polysomes from SLE virus-infected cells were prepared and separated from contaminating nucleocapsid by centrifugation on discontinuous sucrose gradients. RNA extracted from these polysome preparations was analyzed by sucrose gradient centrifugation and agarose gel electrophoresis. The 45S SLE virus genome-size molecule was found to be the only RNA species associated with the polysomes. This molecule was sensitive to RNase digestion and was released from polysomes by EDTA and puromycin treatment. These findings provide direct evidence that the 45 S SLE virus RNA serves as the messenger during virus replication, in contrast to the 26S RNA species which functions as the predominant messenger during alphavirus replication.     

Comparative morphology of the sagittal otolith in Serranus spp.

Variations in the morphology of saccular otoliths (sagittae) among three sympatric species of the genus Serranus ( S. atricauda , S. cabrilla and S. scriba ) from the Canary Islands were investigated. Although the otolith gross morphology was similar among species, S. scriba was distinct in having a rostrum which had a slight turning at the tip and a more funnel‐like ostium. The shallower water species ( S. scriba ) had otolith and sulcus areas which were smaller than the deeper water species ( S. cabrilla and S. atricauda ). The sulcus acusticus and ostium size were correlated with the habit depth of the species, with the highest values in the deepest species, S. cabrilla . The otolith outline shape indices changed with size (total length) of the species, and allowed the separation of the species by means of a discriminate function.     

Characterization of cytoplasmic and nuclear genomes in the colorless alga Polytoma. II. General characterization of organelle nucleic acids.

Polytoma obtusum has a main band DNA (alpha) with a buoyant density in CsC1 of rho = 1.711 g/ml and a light DNA satellite (beta) with rho = 1.682 g/ml. beta-DNA was substantially enriched in a fraction containing small leucoplast fragments and some mitochondria, which was obtained in a pellet sedimenting between 3,000 g and 5,000 g. A crude mitochondrial pellet was also obtained by sedimenting at 12,000 g to recover particulates remaining in the supernate after 10 min at 5,000 g. This fraction contained a third DNA component (gamma) with rho = 1.714 g/ml. We have concluded that the leucoplasts of P. obtusum contain the beta-DNA (1.6882) and the mitochondria possess the gamma-component (1.714). Two distinct classess of ribosomes were isolated and separated by sucrose density gradients, a major 79S species and a minor species at 75S. The major species possessed the 25S and 18S ribosomal RNA (rRNA), characteristic of cytoplasmic ribosomes, and these particles co-sedimented in sucrose gradients with the 79S cytoplasmic ribosomes of Chlamydomonas reinhardtii. The minor species was present in about 2% of the total ribosomal population but showed an eight-to-ninefold enrichment in the leucoplast pellet, suggesting that it was of organelle origin. These 73S particles had RNA components migrating very closely with the 18S and 25S species of the 79S ribosomes, but the base composition of the rRNA from these two classes of ribosomes was significantly different; the rRNA from the 79S ribosomes had a G+C mole ratio of 50.0%, while the rRNA from the 73S class had a ratio of 47.5%. By comparison, chloroplast ribosomes of C. reinhardtii were found to sediment at 70S and contain rRNA molecules of 23S and 16S, with a G + C content of 51.0%. These findings support the concept that the Polytoma leucoplast possesses characteristic genetic and protein-forming systems.     

国产海桑属（Sonneratia Linn．f．）植物的形态解剖

本文描述我国海南岛产的卵叶海桑、海南海桑、杯萼海桑、拟海桑、海桑等５种海桑属植物的叶、花、果实、种子、木材等的形态结构;分析它们的主要特征在各种植物之间的异同．观察结果表明,海南海桑和拟海桑两新种的形态结构特征与其它各种植物有明显的不同,并讨论它们之间的分类关系。     

Evolution of chromosomal variation in cottontails, genus Sylvilagus (Mammalia: Lagomorpha). II. Sylvilagus audubonii, S. idahoensis, S. nuttallii, and S. palustris

Chromosomes from cultured fibroblasts of four cottontail species (Sylvilagus audubonii, 2n = 42; S. idahoensis, 2n = 44; S. nuttallii, 2n = 42; and S. palustris, 2n = 38) were analyzed using G- and C-banding techniques. The evolutionary restructuring of the genomes of these species was traced by comparing their banded chromosomes to those of Lepus saxatilis, a species of hare in which the leporid ancestral karyotype is thought to have been conserved. Chromosomal evolution appears to have proceeded primarily through changes in the amount and distribution of heterochromatin and through fixation of Robertsonian fusions. Excluding heterochromatic differences, S. audubonii and S. nuttallii are karyotypically very similar, as are S. aquaticus and S. palustris (previously reported). The genome of the taxonomically controversial species S. idahoensis, compared to other cottontail species, is markedly impoverished in C-band material. These data and those of cottontail species previously described in the literature are incorporated in two alternative phylogenetic schemes.     

Biosystematic study of hexaploids Elymus tschimganicus and E. glaucissimus. II. Interspecific hybridization and genomic relationship.

To investigate genomic relationships of Elymus tschimganicus (Drobov) Tzvelev (2n = 6x = 42, S1S2Y genomes) and E. glaucissimus (M. Pop.) Tzvelev (2n = 6x = 42, S1S2Y genomes), interspecific hybridizations of the two target species were carried out with 27 other Elymus species containing the SH, SY, SYH, SYP, SYW, and SH1H2 genomes, respectively, collected from different geographic regions. Chromosome pairing behavior was analyzed at metaphase I in 27 hybrids representing 23 hybrid combinations, and overall genomic relationships of the two target species with the other Elymus taxa were estimated. The study concluded that (i) interspecific hybridization was principally easy to perform between the Elymus species, but no general pattern of crossability was obtained, and all hybrids were completely sterile, (ii) the two species have a similar meiotic pattern in their hybrids with the other Elymus species, and (iii) species containing the SY, SYP, and SYH genomes have a generally higher level of genomic homology to the target species than those possessing the SH genomes, and the South American hexaploid with the SH1H2 genomes has the lowest level of genomic homology to the two target taxa.     

Plant regeneration from protoplasts of Solanum species with potential agricultural value (S. hjertingii,S. polyadenium,S. capsicibaccatum)

Protoplasts have been isolated from three tuber-bearing Solanum species, S. hjertingii, S. polyadenium and S. capsicibaccatum, that are sexually incompatible with S. tuberosum, but possess potentially useful characters. For isolating protoplasts from leaves of in vitro shoot cultures of S. hjertingii and S. capsicibaccatum growth was improved by including silver thiosulfate in the medium. However, for S. polyadenium, leaves of pot-grown plants were the best source for protoplasts. Following protoplast division and culture, plants were regenerated from protoplasts of each of the species. The pattern of chromosome variation in regenerants was similar to that observed for other diploid and tetraploid Solanum species. The results indicate that it should be possible to introduce the potentially useful germplasm from these wild species into somatic hybrids with S. tuberosum by protoplast fusion.Abbreviations STS silver thiosulfate - BAP benzylaminopurine - GA₃ gibberellic acid - NAA naphthalene acetic acid - IAA indole-3-acetic acid     

Genetic relationships among the oral streptococci.

Genetic relationships and species limits among the oral streptococci were determined by an analysis of electrophoretically demonstrable variation in 16 metabolic enzymes. Fifty isolates represented 40 electrophoretic types, among which the mean genetic diversity per locus was 0.857. Mannitol-1-phosphate dehydrogenase was not detected in isolates of the sanguis species complex, and glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were absent in species of the mutans complex. Clustering from a matrix of Gower's coefficient of genetic similarity placed the 40 electrophoretic types in 10 well-defined groups corresponding to the Streptococcus species S. mutans, S. sobrinus, S. cricetus, S. rattus, S. ferus, S. oralis (mitior), two distinct assemblages of S. sanguis strains, and two subdivisions of "S. milleri." The assignments of isolates to these groups were the same as those indicated by DNA hybridization experiments, and the coefficient of correlation between genetic distance estimated by multilocus enzyme electrophoresis and genetic similarity indexed by DNA hybridization was -0.897 (P less than 0.001) for 50 pairwise combinations of isolates. S. ferus, which is widely believed to be a member of the mutans complex, was shown to be phylogenetically closer to species of the sanguis complex.     

Natural populations of Saccharomyces kudriavzevii in Portugal are associated with oak bark and are sympatric with S. cerevisiae and S. paradoxus

Here we report the isolation of four Saccharomyces species (former Saccharomyces sensu stricto group) from tree bark. The employment of two temperatures (10 degrees C in addition to the more commonly used 30 degrees C) resulted in the isolation of S. kudriavzevii and S. uvarum, two species that grow at low temperatures, in addition to S. cerevisiae and S. paradoxus. A clear bias was found toward the bark of certain trees, particularly certain oak species. Very often, more than one Saccharomyces species was found in one locality and occasionally even in the same bark sample. Our evidence strongly suggests that (markedly) different growth temperature preferences play a fundamental role in the sympatric associations of Saccharomyces species uncovered in this survey. S. kudriavzevii was isolated at most of the sites sampled in Portugal, indicating that the geographic distribution of this species is wider than the distribution assumed thus far. However, the Portuguese S. kudriavzevii population exhibited important genetic differences compared to the type strain of the species that represents a Japanese population. In this study, S. kudriavzevii stands out as the species that copes better with low temperatures.     

DNA polymerases from Chlamydomonas reinhardii. Purification and properties.

Three DNA polymerase activities, A, B and C, were identified in extracts of exponentially growing synchronous cultures of Chlamydomonas reinhardii, and DNA polymerases A and B were characterized in detail. Both enzymes have the same binding affinity for DEAE-cellulose at pH 7.8, but can be distinguished from each other by their behaviour on phosphocellulose and DNA-agarose. 'Activated' calf thymus DNA was used as template, and the pH, K+ and bivalent-cation optima were measured. DNA polymerase A sediments at 5.3 S in glycerol gradients, with an apparent mol.wt. of 90000-100000. Polymerase B sediments between 8S and 10S in 100mM-KCl, the predominant species having an apparent mol.wt. of 200000. In 200mM-KCl, polymerase B dissociates to a single species, which sediments at 5.8S. A 3S species was found in aged preparations of both enzymes. The activity of polymerase B from cells harvested during nuclear DNA synthesis is twice that found in Chlamydomonas at other times during the cell cycle.     

Nucleic acids of respiratory syncytial virus.

Analysis of purified respiratory syncytial virus revealed that the virion RNA was composed of 50S, 28S, 18S, and 4S species. The 18S and 28S species were presumed to represent host rRNA since virus grown in actinomycin D-treated cells contained only 50S and 4S RNAs. Actinomycin D treatment stimulated production of infectious respiratory syncytial virus 5- to 10-fold. The 50S virion RNA was shown to hybridize with polyadenylated mRNA's isolated from infected cells, indicating that respiratory syncytial virus RNA is of negative-strand sense. Six mRNA's were identified by polyacrylamide gel electrophoresis.     

Two species of Strobilomyces (Boletaceae, Boletales), S. seminudus and S. hongoi sp. nov. from Japan

We describe and illustrate two Strobilomyces species, S. seminudus and S. hongoi sp. nov. These two species have been confused and treated as a single species (i.e. S. seminudus). However recent studies based on population genetics have implied that they are reproductively isolated. In the present study we found that they are phylogenetically and morphologically distinct. The molecular phylogenetic trees inferred from the partial sequences of the largest subunit of RNA polymerase II (RPB1) and the second-largest subunit of RNA polymerase II (RPB2) support the differentiation of these two species as well as their differentiation from other related species. Strobilomyces seminudus is characterized by a stipe with an annular zone, becoming distinctly thickened near the apex and mottled with appressed-tomentose scales near the base. In contrast S. hongoi is characterized by a stipe with a remarkable reticulum at the upper and middle part and with minutely warty scales downward. Stipe characteristics also are useful for distinguishing these two species from other related species. In addition the incompletely reticulated basidiospores of these two species are also distinct from those of related species (i.e. S. foveatus).     

A comparison of the unfolding and dissociation of the large ribosome subunits from Rhodopseudomonas·spheroides N.C.I.B. 8253 and Escherichia coli M.R.E. 600

1. The behaviour of the large ribosomal subunit from Rhodopseudomonas spheroides (45S) has been compared with the 50S ribosome from Escherichia coli M.R.E. 600 (and E. coli M.R.E. 162) during unfolding by removal of Mg(2+) and detachment of ribosomal proteins by high univalent cation concentrations. The extent to which these processes are reversible with these ribosomes has also been examined. 2. The R. spheroides 45S ribosome unfolds relatively slowly but then gives rise directly to two ribonucleoprotein particles (16.6S and 13.7S); the former contains the intact primary structure of the 16.25S rRNA species and the latter the 15.00S rRNA species of the original ribosome. No detectable protein loss occurs during unfolding. The E. coli ribosome unfolds via a series of discrete intermediates to a single, unfolded ribonucleoprotein unit (19.1S) containing the 23S rRNA and all the protein of the original ribosome. 3. The two unfolded R. spheroides ribonucleoproteins did not recombine when the original conditions were restored but each simply assumed a more compact configuration. Similar treatments reversed the unfolding of the E. coli 50S ribosomes; replacement of Mg(2+) caused the refolding of the initial products of unfolding and in the presence of Ni(2+) the completely unfolded species (19.1S) again sedimented at the same rate as the original ribosomes (44S). 4. Ribosomal proteins (25%) were dissociated from R. spheroides 45S ribosomes by dialysis against a solution with a Na(+)/Mg(2+) ratio of 250:1. During this process two core particles were formed (21.2S and 14.2S) and the primary structures of the two original rRNA species were conserved. This dissociation was not reversed. With E. coli 50S approximately 15% of the original ribosomal protein was dissociated, a single 37.6S core particle was formed, the 23S rRNA remained intact and the ribosomal proteins would reassociate with the core particle to give a 50S ribosome. 5. The ribonuclease activities in R. spheroides 45S and E. coli M.R.E. 600 and E. coli M.R.E. 162 50S ribosomes are compared. 6. The observations concerning unfolding and dissociation are consistent with previous reports showing the unusual rRNA complement of the mature R. spheroides 45S ribosome and show the dependence of these events upon the rRNA and the importance of protein-protein interactions in the structure of the R. spheroides ribosome.     

中国竹亚科思劳竹属一新种——万石山思劳竹

描述了竹亚科思劳竹属一新种——万石山思劳竹（Schizostachyum wanshishanensis S.H.Chen,K.F.Huang et H.Z.Guo）。该种与思劳竹（S.pseudolima McClure）近缘,但本种箨片较平直,且短,长不及箨鞘之1/2,叶表无毛,叶背具柔毛,易于区别;本种也与沙罗单竹（S.funghomii McClure）近缘,但本种秆梢端细长下垂,叶鞘具有白色短刺毛,易于区别。     

Berkleasmium crunisia sp. nov. and its phylogenetic affinities to the Pleosporales based on 18S and 28S rDNA sequence analyses

Berkleasmium crunisia sp. nov. is described from a decaying rachis of Calamus sp. (Arecaceae) from Khuan Ka Long, Satun Province, Thailand. This Berkleasmium species differs morphologically from other species in possessing subtending cells and larger conidia. The phylogenetic relationship of the genus Berkleasmium among sexual ascomycetes also was examined. Sequence analyses from 18S, 28S and ITS-5.8S rDNA were analyzed phylogenetically under maximum parsimony, Bayesian and neighbor joining criteria. Phylogenies revealed that Berkleasmium is not monophyletic. Berkleasmium micronesicum and B. nigroapicale are related to Westerdykella cylindrica and Sporormia australis, which are members of the family Sporormiaceae (Pleosporales). Other species, including our new taxon, appear to share phylogenetic affinities with other anamorphic fungi, whose classification within the Pleosporales is still obscure. Analyses of 18S, 28S, ITS (+5.8S) rDNA and combined (18S+28S) gene sequences fail to give sufficient phylogenetic resolution within the Pleosporales.     

Mating interactions between Schistosoma haematobium and S. mansoni

Schistosoma haematobium and S. mansoni are two medically important schistosomes, commonly occurring sympatrically in Africa and so potentially able to infect the same human host. Experiments were designed to study the mating behaviour of these two species in mixed infections in hamsters. Analysis of the data obtained showed that both heterospecific and homospecific pairs readily form. No significant difference was seen between the two species in their ability in forming pairs, however, S. mansoni showed a greater homospecific mate preference. Analysis of the data using the Mantel-Haenszel test suggests that mating competition does occur between S. haematobium and S. mansoni, the former being the more dominant species. Both species appeared to be able to change mate, with S. haematobium showing a greater ability in taking S. mansoni females away from S. mansoni males when introduced into a pre-established S. mansoni infection highlighting the competitiveness of S. haematobium. The significance of the results is discussed in relation to the epidemiological consequences occurring in Senegal, and other areas where both species are sympatric.     

Low molecular weight RNA species from chromatin.

Several methods of preparing low molecular weight RNA from chick embryo chromatin have been examined. Traditional methods for dissociating chromatin utilizing high concentrations of salt (greater than 2 M) followed by high-speed centrifugation resulted in very low yields of RNA. Increased yields of RNA were obtained by treating chromatin at lower salt concentration (0.2-0.5 M). By using low salt extraction and sodium dodecyl sulfate-phenol deproteinization, six to eight low molecular weight homogeneous RNA species were isolated from chick embryo chromatin and mouse myeloma chromatin. In the myeloma system, all these RNAs are metabolically stable. Each component is homogeneous as examined by gel electrophoresis and hybridizes with mouse DNA at a rate consistent with a single species. There are multiple gene copies for these RNA species in the mouse genome, varying from 100 to 2000 copies for the different species. One of these RNAs is identical with 5S rRNA. In addition, the redundancy of genes for 18S, 28S, and 5S rRNA and tRNA was determined. Approximately 300 copies for 18 and 28S rTRNA and 500 copies for 5S rRNA were found. tRNAs were on an average 110-fold redundant with about 55 different species measured.     

The subunit characterization of Callinectes sapidus hemocyanin.

Hemocyanin from the blue crab, Callinectes sapidus, sediments at 25.7 S and has a native molecular weight of 940 000 +/- 20 000. Under solution conditions of increased pH (approximately 10) or ionic strength, the native molecule dissociates to a 17 S species. Reversal of this dissociation was unsuccessful. At pH 10 and with the removal of Mg2+, the 17 S species reversibly dissociates to form a subunit species which sediments at 6 S. A comparison of the circular dichroic spectra of the 25.7 S and 6 S hemocyanins suggests that little happens to the structural integrity of the polypeptide backbone upon the two dissociations. Molecular weight estimations under reducing and denaturing conditions indicate that the 6 S hemocyanin species represents the constituent polypeptide chain of the protein molecule. Chemical analysis suggests the presence of a small amount, less than 3%, of carbohydrate bound to the polypeptide chain. Electrophoresis of the hemocyanin in the presence of sodium dodecyl sulfate or urea reveals two major electrophoretic species of either slightly different chemical composition or slightly different polypeptide chain length.