Revision of the Genus Scopelogadus (Melamphaidae). 4. S. multilamellatus sp. n. and S. unispinis

Journal of Ichthyology - A new species Scopelogadus multilamellatus sp. n. has been described from the tropical waters of the Indian Ocean. The new species has a large number of pseudobranchial...     

栽培高粱、甜高粱和拟高粱比较基因组原位杂交分析

用一种植物的总基因组DNA与近缘或远缘物种的染色体杂交,可以研究植物近缘或远缘物种基因组进化关系。以拟高粱总基因组DNA为探针,对栽培高粱、甜高粱基因组进行杂交,结果表明栽培高粱、甜高粱和拟高粱基因组中重复序列存在很大的同源性,基因组进化关系表现出保守性。栽培高粱与拟高粱基因组间重复序列的同源性要比甜高粱与拟高粱间重复序列的同源性高。     

Sphagnum divinum (sp. nov.) and S. medium Limpr. and their relationship to S. magellanicum Brid.

Sphagnum magellanicum has been viewed as being a predominantly circumpolar species in the northern hemisphere, but it occurs in the southern hemisphere and was originally described from the southern parts of Chile. It is an ecologically important species in mire ecosystems and has been extensively used as a model to study processes of growth, carbon sequestration and peat decomposition. Molecular and experimental studies have, however, revealed genetic structure within S. magellanicum, and morphological differences associated with these genetic groups. Here we describe Sphagnum divinum in Sphagnum subgenus Sphagnum (Sphagnaceae, Bryophyta) as a new species, based on molecular and morphological evidence. Sphagnum medium is reinstated as a distinct species and is epitypified. Consequently, a new species concept of S. magellanicum is presented including an epitypification. Important morphological characters to separate these three species in the field and under the microscope are presented. Ecology and distribution differ among the species; S. divinium has a wide habitat range including mire margin, forested peatlands and moist heaths, and a circumpolar distribution around the northern hemisphere. Sphagnum medium seems to be more restricted to ombrotrophic mire expanse habitats and shows an amphi-Atlantic distribution in the northern hemisphere. Sphagnum magellanicum has a very broad ecological niche in peatlands and is found in most mire habitats in Tierra del Fuego on the southern tip of South America.     

The 5S and 5.8S ribosomal RNA sequences of Tetrahymena thermophila and T. pyriformis

The nucleotide sequences of the 5S rRNAs of Tetrahymena thermophila and two strains of T. pyriformis have been determined to be identical. The 5.8S rRNA sequences have also been determined; these sequences correct several errors in an earlier report. The 5.8S rRNAs of the two species differ at a single position. The sequencing results indicate that the species are of recent common ancestry. Molecular evidence that has been interpreted in the past as suggestive of an ancient divergence has been reviewed and found to be consistent with a T. pyriformis complex radiation beginning approximately 30-40 million years ago.     

The 5S and 5.8S Ribosomal RNA Sequences of Tetrahymena thermophila and T. pyriformis1

The nucleotide sequences of the 5S rRNAs of Tetrahymena thermophila and two strains of T. pyriformis have been determined to be identical. The 5.8S rRNA sequences have also been determined; these sequences correct several errors in an earlier report. The 5.8S rRNAs of the two species differ at a single position. The sequencing results indicate that the species are of recent common ancestry. Molecular evidence that has been interpreted in the past as suggestive of an ancient divergence has been reviewed and found to be consistent with a T. pyriformis complex radiation beginning approximately 30–40 million years ago.     

Studies and sequences of Escherichia coli 4.5 S RNA.

4.5 S RNA, a biologically stable species with electrophoretic properties intermediate between 5 S and transfer RNAs, has been isolated from Escherichia coli and characterized. No function has yet been found for this molecule. Its primary structure and behavior suggests an unusually stable and possibly unique secondary structure. Even from single species of E. coli, there is some sequence heterogeneity within the molecule. The sequence of a major species from MRE 600 is: (see article). Methods for getting sequence overlaps on this highly structured RNA are described, and a possible functional role for 4.5 S RNA is discussed.     

Molecular cytogenetics of the ribosomal (18S + 28S and 5S) DNA loci in primitive and advanced urodele amphibians.

In the present work we performed a cytogenetic analysis of the ribosomal (18S + 28S and 5S) loci in amphibian species belonging to the advanced family Salamandridae (genera Triturus, Salamandra, and Salamandrina) and in the primitive hynobiid Salamandrella keyserlingii (family Hynobiidae). In each analyzed karyotype the 5S rDNA sites appear to be stable, and definite in number, while an intraspecific variability both in number and chromosomal location of the 18S + 28S rDNA loci has been found in some Triturus species. In particular, an evolutionary trend toward a large intraspecific variability of the 18S + 28S rDNA loci has been found in the T. vulgaris species group. A structural analysis of the ribosomal repetition units demonstrates the occurrence of a length polymorphism within the 18S + 28S rDNA repeats in the examined species of the family Salamandridae; however, this polymorphism is rather limited, even in those Triturus species characterized by high intragenomic variability of the ribosomal sites. We show that in T. vulgaris meridionalis the variant repetition units actually segregate with individual chromosomes. This implies that they are not intermingled in the ribosomal clusters.     

Ribosomal RNA genes of Saccharomyces cerevisiae. I. Physical map of the repeating unit and location of the regions coding for 5 S, 5.8 S, 18 S, and 25 S ribosomal RNAs.

The organization of the ribosomal DNA repeating unit from Saccharomyces cerevisiae has been analyzed. A cloned ribosomal DNA repeating unit has been mapped with the restriction enzymes Xma 1, Kpn 1, HindIII, Xba 1, Bgl I + II, and EcoRI. The locations of the sequences which code for 5 S, 5.8 S, 18 S, and 25 S ribosomal RNAs have been determined by hybridization of the purified RNA species with restriction endonuclease generated fragments of the repeating unit. The position of the 5.8 S ribosomal DNA sequences within the repeat was also established by sequencing the DNA which codes for 83 nucleotides at the 5' end of 5.8 S ribosomal RNA. The polarity of the 35 S ribosomal RNA precursor has been established by a combination of hybridization analysis and DNA sequence determination and is 5'-18 S, 5.8 S, 25 S-3'.     

Mallomonas weei (Synurophyceae), a new species from North Carolina, U.S.A.

A new species of Mallomonas, M.weei, is described from North Carolina, U.S.A. Fine structure of scales and bristles has been studied using scanning and transmission electron microscopy. The new species is placed in the section Mallomonas, series Intermediae.     

Deoxyribonuclease II activity in Sarcocystis fusiformis and S. gigantea cysts

In the cysts of S. fusiformis and S. gigantea parasites from the esophagus of buffaloes and sheep the increase in the deoxyribonuclease II activity during aging of cysts of both species has been established. It has been found that in all age groups of S. fusiformis cysts the activity of this enzyme is greater than in the corresponding age groups of S. gigantea.     

Competence for Natural Genetic Transformation in the Streptococcus bovis Group Streptococci S. infantarius and S. macedonicus

Natural genetic transformation is common among many species of the genus Streptococcus, but it has never, or rarely, been reported for the Streptococcus pyogenes and S. bovis groups of species, even though many streptococcal competence genes and the competence regulators SigX, ComR, and ComS are well conserved in both groups. To explore the incidence of competence in the S. bovis group, 25 isolates of S. infantarius and S. macedonicus were surveyed by employing culture in chemically defined media devoid of peptide nutrients and treatment with synthetic candidate pheromone peptides predicted from the sequence of the gene comS. Approximately half of strains examined were transformable, many transforming at high rates comparable to those for the well-characterized streptococcal natural transformation systems. In S. infantarius, nanomolar amounts of the synthetic pheromone LTAWWGL induced robust but transient competence in high-density cultures, but mutation of the ComRS locus abolished transformation. We conclude that at least these two species of the S. bovis group retain a robust system of natural transformation regulated by a ComRS pheromone circuit and the alternative sigma factor SigX and infer that transformation is even more common among the streptococci than has been recognized. The tools presented here will facilitate targeted genetic manipulation in this group of streptococci.     

Identification of Enterococcus spp. based on specific hybridisation with 16S rDNA probes

The conventional methods for routine enterococci species identification are usually based on phenotypic characteristics. However, in recent years, some studies have defined specific probes based on both 16S and 23S rRNA genes for the identification of some Enterococcus spp. A set of probes based on the 16S rRNA gene has been developed in order to evaluate the usefulness of a six-step biochemical key for species level identification of enterococci. Probe specificity has been evaluated with type collection and environmental strains by dot blot hybridisation. A high correlation was obtained between biochemical key and hybridisation identifications. This set of probes provides a confirmative method for phenotypic species identification.     

狭义干蘑属(蘑菇目)概要及新的系统学处理

对狭义干蘑属(Xerulas.str.)的范围进行了重新界定,该属仅包括模式种干蘑(X.pudens)及其周围的几个种。属的特征是担子果金钱菌状,有假根;菌盖及菌柄表面干燥,被有黄色至褐色直立、披针形的刚毛;菌褶边缘无不育带;子实层有近梭形的小担子。这些特征可以将干蘑属的物种从干蘑属-小奥德蘑属复合群中分开。现知干蘑属包含六种,本文提供了这些种的检索表,并对各种进行了描述、图示或讨论。其中,硬毛干蘑(X.strigosa)是一新种,它与干蘑(X.pudens)和中华干蘑(X.sinopudens)相似,但与干蘑不同在于其担孢子较长,锁状联合稀少,侧生囊状体顶端壁薄;与中华干蘑的区别在于其侧生囊状体壁厚,顶端有头状至近头状膨大并覆盖有结晶,担孢子宽椭圆形至椭圆形。中华干蘑和小刺干蘑(X.setulosa)分别为我国和哥斯达黎加的新记录种。干蘑属虽然广布北半球,但未见东亚-美洲或欧亚广布的物种分布类型。     

A Revision of Aristolochia Linn. from E. & S. Asia

This revision deals with the system, evolution, distribution, cytotaxonomy and taxonomic treatment of the genus Aristolochia Linn. from E. & S. Asia, which covers Japan, USSR (Far East), China, Viet Nam, Laos, Cambodia, Thailand, Burma, India, Bhutan, Nepal, Sikkim, Bangladesh and Pakistan. Total 2 subgenera, 7 sections, 4 series, 68 species and 1 variety (cultivated species not included) are recognized in this treatment, of which 3 sections and 2 species are described as new. In addition, 13 new synonyms and some new records to this region are also included. Ystem Having estimated all the works dealing with the subdivision of the genus by the previous authors, the system of O. C. Schmidt (1935) is chosen as the basis, with a change of the sequence of the subdivisions. The subgenus Pararistolochia (Hutch. & Dalz.) O. C. Schmidt, which has indefinite stamens and gynandrous lobes, seems to be better considered as the most primitive one in the genus, while the subgenus Siphisia (Raf.) Duch., which has definite stamens and gynandrous lobes, anthers arranged in 3 pairs and more modifications of the perianth, seems to be the most advanced one. The perianth of the subgenus Siphisia has differentiated into several types, and it is more rational using this character to classify sections than lobes of the gynostemium. In this way, three new sections has been established. A suggested system of the genus is summarized as follows: Subgen. 1. Pararistolochia (Hutch. & Dalz.) O. C. Schmidt Subgen. 2. Aristolochia: Sect. 1. Aristolochia (2 series), Sect. 2. Gymnolobus Duch. Subgen. 3. Siphisia (Raf.) Duch.: Sect. 3. Pentodon Klotz, Sect. 4. Odontosiphisia J. S. Ma, Sect. 5. Leptosiphisia J. S. Ma, Sect. 6. Nepenthesia Klotz., Sect. 7. Obliquosiphisia J. S. Ma, Sect. 8. Siphisia (2 series). Evolution According to the character analysis of the genera of Aristolochiaceae, the evolutionary trends of the family are proposed as follows: 1, the perianth from double to single, from cup-like to tubular, 2, stamens from indefinite to definite, from separate from pistil to united into a gynostemium with pistil, which is a major evolutionary line in the family, 3, ovary from half-superior to inferior, and 4, fruit from a follicle to a capsule. It is evident that the genus Aristolochia, with a tubular perianth, stamens 6, a gynostemium, an inferior ovary and a capsule, is in highly advanced position in the family. The subgenus Pararistolochia, which has more stamens and more lobes of gynostemium, is very similar to the genus Thottea Rottb. and thus better considered as the most primitive subgenus in the genus. The subgenus Siphisia, which has definite stamens (6) in 3 pairs and 6 lobes of gynostemium as well as the polyploid feature (2n=4x=28), is the most advanced subgenus. As a result of the character analysis, the evolutionary trends of the subgenera in the genus, which are in accordance with those of the family, are proposed as follows: 1. stamens from indefinite to definite, and 2. gynostemium lobes from more to less. Distribution The more primitive subgenus Pararistolochia is only distributed in West Africa (except 1 species in Malesia), the subgenus Aristolochia in the tropical and subtropical regions, rarely in the temperate one, and the most advanced subgenus Siphisia occurs mainly in E. Asia, occasionally in N. America. The result of this work shows that the Hengduan Mountains is the second center of distribution after South America. The second center of distribution is of following features: 1. complex composition of taxa, among 3 subgenera and 8 sections, 2 subgenera and 7 sections have been recorded here, 2. rich in species, more than half of the total E. & S. Asian species, i.e. about 42 species have been found in this region, and 3. numerous endemics, more than 85 percent of the total number of species in the region, i.e. about 35 species, are endemic. Cytotaxonomy and taxonomic treatment The known chromosome numbers in 43 species, with 34 reported by Gregory (1956) and Fedorov (1969), together with 9 species newly reported in this work, show that Subgen. Aristolochia with 2n=2x=14, rarely 12, is apparently more primitive than Subgen. Siphisia with 2n=2x=28.     

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).     

Sound Production in Sturgeon Scaphirhynchus albus and S. platorynchus (Acipenseridae)

Sound production has been recently discovered in several species of Acipenser. Our work has focused on testing for sound production in species of sturgeon in the genus Scaphirhynchus. We discovered that pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon, S. albus produce sounds during the breeding season. These signals may be used as part of efforts to localize populations of sturgeon in the field, including the Alabama sturgeon, S. suttkusi.     

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.     

THE BIRDS OF THE SANTA ELENA PENINSULA, S.W. ECUADOR

A systematic account is given of the birds of the Santa Elena peninsula in S.W. Ecuador, based on three years observations (1954-7) and a collection of 425 skins. The status of individual species is decribed and the different elements of the avifauna discussed, viz. the Equatorial arid fauna, Nearctic migrants, sea-birds, and other wide-ranging forms and waterfowl. Seasonal movements of species of the Equatorial arid fauna are indicated in greater detail than has been previously known. The effect of a recently constructed reservoir on the bird life is mentioned. More detailed knowledge of the occurrence of species from the cold Humboldt current is provided. Several additions to the Ecuadorian list are given, and some birds recorded which were hitherto unknown or very rarely recorded from the west coast of S. America. Various matters of taxonomy affecting races of birds along the whole west coast of S. America are discussed.