B chromosomes in Stylidium crossocephalum (Angiospermae:Stylidiaceae)

Populations of Stylidium crossocephalum contain two common types of B chromosomes, macro B chromosomes and micro B chromosomes. The macro B chromosomes are telocentric, slightly smaller than the smallest A chromosomes and mitotically unstable. They have so far been found associated with 6 of the 16 stable genomes known in S. crossocephalum, occurring in populations covering a substantial portion of the species range. Micro B chromosomes are about one third the length of the smallest A chromosome, acrocentric and show some mitotic instability. They occur associated with 3 stable genomes in populations found in the more medial regions of the species range. Both types of B chromosomes generally show regular behaviour during meiosis, although when two or more are present their pairing efficiency is reduced when compared to the A chromosomes. In addition a single very large mega chromosome was found in a single cell of one heterokaryotypic plant. Its origin although conjectural at this stage may be of relevance in understanding the origin of macro and micro B chromosomes in this species.     

Analysis of soybean chloroplast DNA replication by two-dimensional gel electrophoresis

Chloroplast DNA replication was studied in the green, autotrophic suspension culture line SB-1 of Glycine max. Three regions (restriction fragments Sac I 14.5, Pvu II 4.1 and Pvu II 14.8) on the plastome were identified that displayed significantly higher template activity in in vitro DNA replication assays than all other cloned restriction fragments of the organelle genome, suggesting that these clones contain sequences that are able to direct initiation of DNA replication in vitro. In order to confirm that the potential in vitro origin sites are functional in vivo as well, replication intermediates were analyzed by two-dimensional gel electrophoresis using cloned restriction fragments as probes. The two Pvu II fragments that supported deoxynucleotide incorporation in vitro apparently do not contain a functional in vivo replication origin since replication intermediates from these areas of the plastome represent only fork structures. The Sac I 14.5 chloroplast DNA fragment, on the other hand, showed intermediates consistent with a replication bubble originating within its borders, which is indicative of an active in vivo origin. Closer examination of cloned Sac I 14.5 sub-fragments confirmed high template activity in vitro for two, S/B 5 and S/B 3, which also seem to contain origin sites utilized in vivo as determined by two-dimensional gel electrophoresis. The types of replication intermediate patterns obtained for these sub-fragments are consistent with the double D-loop model for chloroplast DNA replication with both origins being located in the large unique region of the plastome [17, 18]. This is the first report of a chloroplast DNA replication origin in higher plants that has been directly tested for in vivo function.     

Sympatric occurrence of three cytotypes and four morphological types of B chromosomes of Astyanax scabripinnis (Pisces, Characiformes) in the River Ivaí Basin, state of Paraná, Brazil

Chromosomes of Astyanax scabripinnis from the Tatupeba stream, Ivaí basin (state of Paraná, Brazil), were analyzed. Astyanax scabripinnis population presents 3 different diploid numbers (2n = 46, 48 and 50) and B chromosomes in each cytotype. Eighty per cent of the females among individuals of cytotype I (2n = 50) has a metacentric B macrochromosome, whereas three different types of B chromosomes were identified in individuals of cytotype II (2n = 48). Cytotype III (2n = 46) showed two B chromosomes of different morphologic types (metacentric macrochromosomes and acrocentric) in all specimens and cells analyzed. Constitutive heterochromatin pattern for the three cytotypes showed weak markings in centromeric regions and conspicuous blocks in the telomere regions of ST and A chromosomes. Whereas C-banding showed that B chromosomes were totally or partially heterochromatic, a discussion on their behavior and origin was also undertaken.     

A monophyletic origin of the B chromosomes ofBrachycome dichromosomatica (Asteraceae)

The A and B chromosomes of different karyotype variants (cytodemes A1, A2, A3 and A4) ofBrachycome dichromosomatica were analysed by computer-aided chromosome image analysis and fluorescencein situ hybridisation (FISH). Ribosomal DNA and the B chromosome-specific sequence Bd49 were detected on all B chromosomes. In addition to minor size variation of the Bs, polymorphism of the rDNA and Bd49 position and copy number revealed two major types of B chromosomes. The B chromosomes of all the cytodemes were indistinguishable from each other in length, but that of A3 showed evidence of rearrangements consistent with its long-term geographic isolation. The results presented suggest a monophyletic origin of the B chromosomes ofB. dichromosomatica.     

Frequency of the Insertion Sequence IS4Bsu1 among Bacillus subtilis Strains Isolated from Fermented Soybean Foods in Southeast Asia

Among 45 Bacillus subtilis strains isolated from non-salted types of fermented soybeans produced in several Southeast Asian countries, 20 had the insertion sequence IS4Bsu1 in the chromosome. In contrast, none of 49 B. subtilis strains of non-food origin contained IS4Bsu1. Frequent occurrence of this mobile DNA element in the soybean-fermenting B. subtilis would reflect the fact that few strains flourish on soybeans and thereby contribute to soybean fermentation.     

中国重要检疫性实蝇的全球分布和入侵情况

实蝇是重要的蔬菜瓜果害虫。本文重点概述入侵中国实蝇的寄主植物、原产地、首次发现时间、入侵地、国内外分布和入侵扩散途径,全面整理重要检疫性实蝇的全球分布和入侵情况,同时根据全球重要检疫性实蝇的分布情况为警惕和预防实蝇入侵我国提供理论支持。本文指出,领土相邻是实蝇入侵我国的重要条件：入侵中国的实蝇原产地是中国的邻国日本、印度和泰国,最早发现地是中国的沿海和沿边地区,分别为中国台湾、广西、云南和新疆吐鲁番。寄主植物的种类数量与实蝇的分布范围正相关：橘小实蝇和瓜实蝇是多食性昆虫,分别危害305和61种植物,分别在全球83和58个国家均有发生。枣实蝇、蜜柑大实蝇和黑颜面实蝇是寡食性昆虫,只危害同属植物,仅入侵原产地周边的些许国家。随着国际瓜果贸易交流频繁,全球重要的检疫实蝇由原产地国家逐渐向周边国家扩散,其中油橄榄实蝇、桃果实蝇、埃塞尔比亚寡鬓实蝇、黑樱桃实蝇和苹果实蝇已经入侵至我国周边国家,需要警惕和预防其从沿边省份入侵我国。加强检疫和管理是防治实蝇入侵和扩散的重要手段,同时也需要中国的科研工作者进一步对世界上重大检疫实蝇的入侵风险评估、防控对策、分子鉴定和快速检测方法进行研究。     

The evolutionary history of PDR in <Emphasis Type="Italic">Brachypodium</Emphasis><Emphasis Type="Italic">distachyon</Emphasis> polyploids

The ATP-binding cassette transporter genes include the pleiotropic drug resistance (PDR) family found only in fungi and plants. These transporters transport toxic compounds across biological membranes. Here, we investigated the evolution of the PDR1 gene in Brachypodium distachyon, a widely distributed temperate grass species that belongs to the Poaceae (Gramineae) family, which also contains the domesticated cereal crops. Because this species has multiple ploidy levels, investigating PDR1 evolution in B. distachyon will offer insights into the formation and evolution of polyploidy. From 23 B. distachyon ecotypes, 39 PDR1 homologs were identified. All ecotypes had either one or two PDR1 copies. Based on restriction site analysis, the PDR1 homologs were classified as E or H type. All but one diploid and tetraploid ecotypes had only a single H type PDR1. All but one hexaploid ecotypes had both an E and a H type PDR1. Phylogenetic analysis revealed that each type formed a well-supported cluster. The two PDR1 types appeared to evolve differently. These different evolutionary patterns could indicate a difference in age between the two types or might indicate different mutation rates or selection pressures on the two types. The phylogenetic analysis also revealed that the hexaploid ecotypes shared a genomic origin for their E type PDR1, but there were multiple origins for hexaploid H type PDR1 homologs. Overall, the results suggest that tetraploid and hexaploid might be misnomers in B. distachyon and suggest a complex polyploidization history during B. distachyon evolution.     

Brassica taxonomy based on nuclear restriction fragment length polymorphisms (RFLPs)

Summary RFLPs were used to study genome evolution and phylogeny in Brassica and related genera. Thirtyeight accessions, including 10 accessions of B. rapa (syn. campestris), 9 cultivated types of B. oleracea, 13 nine-chromosome wild brassicas related to B. oleracea, and 6 other species in Brassica and allied genera, were examined with more then 30 random genomic DNA probes, which identified RFLPs mapping to nine different linkage groups of the B. rapa genome. Based on the RFLP data, phylogenetic trees were constructed using the PAUP microcomputer program. Within B. rapa, accessions of pak choi, narinosa, and Chinese cabbage from East Asia constituted a group distinct from turnip and wild European populations, consistent with the hypothesis that B. rapa had two centers of domestication. A wild B. rapa accession from India was positioned in the tree between European types and East Asian types, suggesting an evolutionary pathway from Europe to India, then to South China. Cultivated B. oleracea morphotypes showed monophyletic origin with wild B. oleracea or B. alboglabra as possible ancestors. Various kales constitute a highly diverse group, and represent the primitive morphotypes of cultivated B. oleracea from which cabbage, broccoli, cauliflower, etc. probably have evolved. Cauliflower was found to be closely related to broccoli, whereas cabbage was closely related to leafy kales. A great diversity existed among the 13 collections of nine-chromosome wild brassicas related to B. oleracea, representing various taxonomic states from subspecies to species. Results from these studies suggested that two basic evolutionary pathways exist for the diploid species examined. One pathway gave rise to B. fruticulosa, B. nigra, and Sinapis arvensis, with B. adpressa or a close relative as the initial ancestor. Another pathway gave rise to B. oleracea and B. rapa, with Diplotaxis erucoides or a close relative as the initial ancestor. Raphanus sativus and Eruca sativus represented intermediate types between the two lineages, and might have been derived from introgression or hybridization between species belonging to different lineages. Molecular evidence for an ascending order of chromosome numbers in the evolution of Brassica and allied genera was obtained on the basis of RFLP data and phylogenetic analysis.     

Intra and inter subspecific variation in soluble proteins of Oryza sativa L.

Summary Types representing three subspecies of Oryza sativa, namely, indica, japonica and javanica, and a group of intermediate types collected from North East India, were studied for variation in soluble proteins using acrylamide gel electrophoresis. The study revealed that there was a marked variation within and between varietal groups. Variability for number and intensity of protein bands in indica was wider than in japonica and javanica. Protein pattern in the group comprising N.E. Indian types transgressed that of all three established groups by displaying a wide spectrum. Relative homology, as measured from percentage similarities of N.E. Indian types to the three subspecies, suggested the existence of six different groups. Comparison of varietal groups for the protein mobility pattern showed that japonica and javanica varieties tended to show higher percentages of slow mobility proteins than indica. It appears, from the narrow variability and relatively low percentage of slow mobility proteins, that the japonica and javanica races are of later origin compared to indica. However, the study with a limited number of types suggested the monophyletic origin of varietal groups from an indica-like base predominantly found in the secondary centres of origin of O. sativa.     

The Inc3B determinant of plasmid pT181

Summary A region encompassing the origin of replication of staphylococcal plasmid pT181 has previously been shown to express an incompatibility effect denoted Inc3B, when cloned into another replicon (Novick et al. 1984). In an attempt to understand the mechanism of this incompatibility effect, and its relationship with the function of the replication origin, mutants deficient in this property were isolated and characterized. The results obtained suggest that the Inc3B effect is due to the competition for replication between the replication origin cloned in a hybrid and the origin of an autonomous plasmid. The Inc3B-deficient mutants isolated expressed different degrees of residual incompatibility. The inc3B mutations which did not express any incompatibility were found also to inactivate the function of the replication origin. All the other mutants which expressed residual Inc3B had a functional origin but presented a significantly reduced ability to use this origin when coexisting with a plasmid using a wild-type pT181 origin. It is suggested that these inc3B mutations represent a new type of origin mutation which affects the ability of the origin to compete with other origins using the same replication system, though the function per se of the origin is not significantly impaired.     

Morphological heterogeneity of secretory granules of rat Clara cells: an immunocytochemical study

Summary The secretory granules of rat bronchiolar Clara cells were classified into different types by their ultrastructural appearances followed by immunocytochemistry using anti-rat 10 kDa Clara cell-specific protein (10 kDa CCSP) antibody. One predominant type was the oval to round granule (type A granule), of which the matrix was composed of a map-like mixture of electron-dense and less electron-dense material. Another predominant type was the rod-shaped granule (type B granule). The content of type B granules varied from a finely fibrillar (type B1 granule) to an electron-dense, rod-like (type B3 granule) structure. Various intermediate types (type B2 granule) between type B1 and B3 granules were also found. Small cytoplasmic vesicles were found occasionally in close proximity to type B2 or B3 granule. Another type of granule (type C granule) was large, up to 8 m in diameter, and contained a moderately electron-dense amorphous matrix. Both type A and C granules stained at a similar density with the antibody. The nascent form of type A granules, which was found in the vicinity to the trans face of the Golgi apparatus, was also labeled. On the other hand, the labeling density of type B granules varied: type B1 granules were almost devoid of immunolabeling, whereas type B3 granules were intensely labeled. Type B2 granules stained with the antibody; however, the labeling density was less than that of type B3 granules. The small cytoplasmic vesicles of type B2 granules were labeled. From these findings, it is suggested that the granules of rat Clara cells consist of two types of granules of distinct origin; one appears to derive from condensing vacuoles of Golgi origin, whereas the other may be formed by membranefusions with small cytoplasmic vesicles of unknown source.     

Gene Organization and Sequence Determination of the Two Botulinum Neurotoxin Gene Clusters in Clostridium botulinum Type A(B) Strain NCTC 2916

The gene organization and nucleotide sequence of the type A and B BoNT-gene clusters in Clostridium botulinum strain NCTC 2916 were studied. The aim was to clarify the organization of genes within C. botulinum type A strains possessing an unexpressed BoNT/B gene. The BoNT/A-gene cluster includes genes encoding BoNT, NTNH and a part of P-47 (the gene for this protein was reported in strains of C. botulinum types E and F). Clustered with the silent BoNT/B gene were genes encoding NTNH, P-21 and HA-33. Sequencing analysis of the NTNHs revealed the presence of 471 amino acids identical in the type B and A gene clusters. This gene organization contrasts markedly with the purported organization in strain NCTC 2916 described by Henderson et al. (FEMS Microbiol. Lett. 140, 151–158). In type A(B) strain NCTC 2916, the neurotoxin gene is of type BoNT/A1 within a gene cluster that has identical organization to that found in BoNT/A2 type strains; these observations may be significant in establishing the origin of the BoNT-gene cluster. Received: 28 July 1997 / Accepted: 15 October 1997     

Ultrastructure structure of antennal sensilla of carabid beetle Carabus elysii Thomson, 1856 (Coleoptera: Carabidae)

The sensilla type, number and distribution in male and female adults of Carabus elysii Thomson, 1856 (Coleoptera: Carabidae) were studied using scanning electron microscopy. The results showed that there are seven categories and 12 types of sensilla in C. elysii adults: three types of S.Ch, three types of S.T, two types of S.B and one each of B.B, S.Co, S.Ca and S.Cam. There is no difference between male and female in the types of sensilla. Apart from the significant difference in the number and distribution of S.B.2, S.Co and S.Ca between male dorsal and ventral surfaces, there are no significant differences between male and female antennae. In general, the number of sensilla in females is larger than that in males. The results provide a basic reference for future ultrastructure, electrophysiological, and comparative behavioral studies of Carabus species.     

Genetic relationships within Brassica rapa as inferred from AFLP fingerprints

Amplified fragment length polymorphism (AFLP) markers were employed to assess the genetic diversity amongst two large collections of Brassica rapa accessions. Collection A consisted of 161 B. rapa accessions representing different morphotypes among the cultivated B. rapa, including traditional and modern cultivars and breeding materials from geographical locations from all over the world and two Brassica napus accessions. Collection B consisted of 96 accessions, representing mainly leafy vegetable types cultivated in China. On the basis of the AFLP data obtained, we constructed phenetic trees using mega 2.1 software. The level of polymorphism was very high, and it was evident that the amount of genetic variation present within the groups was often comparable to the variation between the different cultivar groups. Cluster analysis revealed groups, often with low bootstrap values, which coincided with cultivar groups. The most interesting information revealed by the phenetic trees was that different morphotypes are often more related to other morphotypes from the same region (East Asia vs. Europe) than to similar morphotypes from different regions, suggesting either an independent origin and or a long and separate domestication and breeding history in both regions.     

NATURAL HYBRIDIZATION AMONG FOUR SPECIES OF BAPTISIA (LEGUMINOSAE)

Alston , R. E., and B. L. Turner . (U. Texas, Austin.) Natural hybridization among four species of Baptisia (Leguminosae). Amer. Jour. Bot. 50(2): 159–173. Illus. 1963.— Interspecific hybridization involving 4 species of Baptisia (B. leucophaea, B. sphaerocarpa, B. nuttalliana, and B. leucantha) has been studied by means of extensive field work and subsequent morphological and chromatographic analyses. As a result of these studies, numerous hybridizing populations involving any 2, 3 and, in 1 instance, 4 species have been located. Near Dayton, Texas, all 4 species and all 6 of the possible 2-way hybrid combinations have been found in a single field. Approximately 125 different chemical compounds have now been detected in the 4 species. Many of these compounds serve as species specific markers useful in the validation of specific hybrid types. Hybrids between B. leucophaea and B. sphaerocarpa and between B. leucophaea and B. nuttalliana are numerous, and in these large hybrid swarms a chromatographic and morphological analysis of population structure is possible. The former combination provides an excellent opportunity for the utilization of chemical markers as criteria for introgressive hybridization. The hybrid B. leucantha × B. sphaerocarpa is frequently encountered and contains a large number of compounds species-specific for one or the other parental species. The other 3 hybrid types have been found infrequently. Certain hybrid types are generally similar morphologically (e.g., B. leucantha × B. sphaerocarpa as opposed to B. leucantha × B. nuttalliana), and chromatographic techniques are of great value in the absolute identification of such plants, especially in complex populations where backcrossing further complicates the interpretation of the background of a plant from exomorphic features alone.     

弹尾纲刺齿虫兆属的自然分布扩散及地理起源

基于刺齿虫兆属的自然地理分布特征和调查资料,讨论了弹尾纲刺齿虫兆属的自然分布、扩散和地理起源。结果显示,全球已经描述的57种刺齿虫兆,不仅主要分布于亚洲(54种),而且中国的物种数量最多(32种),土著种数量亦最多(23种)。亚洲之外美国大陆的3个州有2种(全为广布种);夏威夷有6种(包括3个广布种)。作者初步提出了刺齿虫兆属起源和扩散的假设。     

A simple chromosomal marker can reliably distinguishes <Emphasis Type="Italic">Poncirus</Emphasis> from <Emphasis Type="Italic">Citrus</Emphasis> species

Several chromosome types have been recognized in Citrus and related genera by chromomycin A₃ (CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata (“Barnes”, “Fawcett”, “Flying Dragon”, “Pomeroy”, “Rubidoux”, “USDA”) and one P. trifoliata × C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed a similar CMA⁺ banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore, this B chromosome can be used as a marker to recognize the intergeneric Poncirus × Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic cell fusions involving trifoliate orange germplasm. During the submission of this paper, we analyzed 25 other citrus cultivars with the same methodology and we found that the chromosome marker reported here can indeed distinguish Poncirus trifoliata from grapefruits, pummelos, and one variegated access of Citrus, besides the previously reported access of limes, limons, citrons, and sweet-oranges. However, among 14 mandarin cultivars, two of them displayed a single B/5S-45S chromosome, whereas in Citrus hystrix D.C., a far related species belonging to the Papeda subgenus, this chromosome type was found in homozygosis. Since these two mandarin cultivars are probably of hybrid origin, we assume that for almost all commercial cultivars and species of the subgenus Citrus this B type chromosome is a useful genetic marker.     

Genetic diversity and similarity in the Barbarea vulgaris complex (Brassicaceae)

Two subspecies of Barbarea vulgaris are taxonomically recognized as ssp. vulgaris and ssp. arcuata. In addition, two types of Barbarea vulgaris ssp. arcuata occurs in Denmark. The G‐type is resistant to an herbivorous flea beetle (Phyllotreta nemorum) whereas the P‐type is susceptible. A previous study suggested that the P‐type evolved by a loss of resistance from a resistant progenitor. We analyzed the genetic relatedness among eight Barbarea taxa: B. vulgaris spp. vulgaris, B. vulgaris ssp. arcuata G‐ and P‐types, hybrids between the types, B. verna, B. intermedia, B. stricta, B. orthoceras and B. australis, using AFLP and SSR markers. A clear distinction between the G‐ and P‐types was revealed. Both were distinct from B. vulgaris ssp. vulgaris, the G‐type less so than the P‐type. Barbarea verna and B. intermedia formed unambiguous clusters, whereas the remaining taxa produced less discrete groupings. Possible evolutionary scenarios for flea‐beetle resistance and susceptibility are discussed, including lineage sorting from a polymorphic ancestral population, and de novo loss of resistance in the P‐type of B. vulgaris ssp. arcuata.     

The systematic significance of surface features of theBalanophora tuber (Balanophoraceae)

The surface ofBalanophora tubers consists of a nonepidermal layer made up of two distinctive types of cells, armature cells and stellate wart cells. Both cell types are provided with a heavy wall, and are dead at maturity. Stellate warts in the three species investigated,B. elongata, B. fungosa, andB. hansenii, séem to be uniform in appearance, but armature cells are extremely distinctive for each species. They are present in large, agglomerate masses in the first, singly or in very small clusters in the second, and as completely free, individual, acicular cells in the third species. Such differences are believed to be significant systematically, and the separation ofB. hansenii is thus probably justified. Notwithstanding superficial similarities, stellate warts do not seem to be comparable to the lenticels of other plants.     

Genetic diversity of free-living Symbiodinium in surface water and sediment of Hawai‘i and Florida

Marine dinoflagellates in the genus Symbiodinium are primarily known for their symbiotic associations with invertebrates and protists, although they are also found free-living in nanoplankton and microphytobenthic communities. Free-living Symbiodinium are necessary for hosts that must acquire their symbionts anew each generation and for the possible reestablishment of endosymbiosis in bleached adults. The diversity and ecology of free-living Symbiodinium are not well studied by comparison with their endosymbiotic counterparts, and as a result, our understanding of the linkages between free-living and endosymbiotic Symbiodinium is poor. Here, we begin to address this knowledge gap by describing the genetic diversity of Symbiodinium in the surface water and reef sediments of Hawai‘i and Florida using Symbiodinium-specific primers for the hypervariable region of the chloroplast 23S domain V (cp23S-HVR). In total, 29 Symbiodinium sequence types were detected, 16 of which were novel. The majority of Symbiodinium sequence types in free-living environments belonged to clades A and B, but smaller numbers of sequence types belonging to clades C, D, and G were also detected. The majority of sequences recovered from Hawai‘i belonged to clades A and C and those from Florida to clade B. Such distribution patterns are consistent with the endosymbiotic diversity previously reported for these two regions. The ancestral sequence types in each clade were typically recovered from surface water and sediments both in Hawai‘i and Florida and have been previously reported as endosymbionts of a range of invertebrates, suggesting that these types have the capacity to exploit a range of very different habitats. More derived sequence types in clades A, B, C, and G were not recovered here, suggesting they are potentially restricted to endosymbiotic environments.