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1.
We have investigated the floral ontogeny of Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis (of the eucalypt group, Myrtaceae) using scanning electron microscopy and light microscopy. Several critical characters for establishing relationships between these genera and to the eucalypts have been determined. The absence of compound petaline primordia in Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis excludes these taxa from the eucalypt clade. Post-anthesis circumscissile abscission of the hypanthium above the ovary in Stockwellia, Eucalyptopsis and Allosyncarpia is evidence that these three taxa form a monophyletic group; undifferentiated perianth parts and elongated fusiform buds are characters that unite Stockwellia and Eucalyptopsis as sister taxa. No floral characters clearly associate Arillastrum with either the eucalypt clade or the clade of Stockwellia, Eucalyptopsis and Allosyncarpia.We gratefully acknowledge Clyde Dunlop and Bob Harwood (Northern Territory Herbarium) for collecting specimens of Allosyncarpia, and Bruce Gray (Atherton) for collecting specimens of Stockwellia. The Australian National Herbarium (CANB) kindly lent herbarium specimens of Eucalyptopsis for examination. This research was supported by a University of Melbourne Research Development Grant to Andrew Drinnan. 相似文献
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A pea rust fungus, Uromyces viciae-fabae, has been classified into two varieties, var. viciae-fabae and var. orobi, based on differences in urediniospore wall thickness and putative host specificity in Japan. In principal component analyses, morphological features of urediniospores and teliospores of 94 rust specimens from Vicia, Lathyrus, and Pisum did not show definite host-specific morphological groups. In molecular analyses, 23 Uromyces specimens from Vicia, Lathyrus, and Pisum formed a single genetic clade based on D1/D2 and ITS regions. Four isolates of U. viciae-fabae from V. cracca and V. unijuga could infect and sporulate on P. sativum. These results suggest that U. viciae-fabae populations on different host plants are not biologically differentiated into groups that can be recognized as varieties.Contribution no. 184, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan 相似文献
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The large numbers of duplicated pairs of genes in zebrafish compared to their mammalian counterparts has lead to the notion
that expression of zebrafish co-orthologous pairs in some cases can together describe the expression of their mammalian counterpart.
Here, we explore this notion by identification and analysis of a second zebrafish ortholog of the mammalian Kit receptor tyrosine kinase (kitb). We show that in embryos, kitb is expressed in a non-overlapping pattern to that of kita, in the anterior ventral mesoderm, Rohon-beardRohon–Beard neurons, the otic vesicle, and trigeminal ganglia. The expression
pattern of kita and kitb in zebrafish together approximates that of Kit in mouse, with the exception that neither zebrafish kit gene is expressed in primordial germ cells, a site of kit expression in the mouse embryo. In addition, zebrafish kita is expressed in a site of zebrafish primitive hematopoiesis but not required for blood development, and we fail to detect
kitb expression in sites of zebrafish hematopoiesis. Thus, the expression and function of zebrafish kit genes cannot be described as a simple partition of the expression and function of mouse Kit. We discuss the possibility that these unaccounted for expression domains and functions are derived from more ancestral gene
duplications and partitioning instead of the relatively recent teleost teleost-specific duplication.
Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users. 相似文献
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Seishi Kimura Daniel Golani Yukio Iwatsuki Motohiko Tabuchi Tetsuo Yoshino 《Ichthyological Research》2007,54(2):145-159
The Indo-Pacific marine atherinid fishes Atherinomorus forskalii (Rüppell, 1838), Atherinomorus lacunosus (Forster, 1801), and Atherinomorus pinguis (Lacepède, 1803) are redescribed as valid species based on the types and non-type specimens collected throughout the Indo-Pacific.
They are similar to each other chiefly in having a wide midlateral band (almost the same or greater than the midlateral scale
width), large mouth (posterior tip of upper jaw reaching to or beyond a vertical through anterior margin of pupil), and no
distinct tubercle at the posterior end of the dentary. All three species are distinguishable from congeners by those characters.
The three species have long been confused with each other or synonymized erroneously as a single species. Atherinomorus forskalii, known from the Red Sea and eastern Mediterranean, differs from Atherinomorus lacunosus and Atherinomorus pinguis in having conspicuous, large endopterygoid teeth, forming obvious tooth ridges. Atherinomorus lacunosus, widely distributed in almost the entire Indo-Pacific, from East Africa to Tonga, north to southern Japan, and south to northern
Australia, differs from Atherinomorus pinguis in having a wider midlateral band (the lower margin reaching to almost the center of the fourth scale row at level of the
anal fin origin vs. the lower margin reaching to the ventral end of the third scale row in Atherinomorus pinguis) and more numerous midlateral scales (40–44 vs. 38–41 in Atherinomorus pinguis). Atherina morrisi Jordan and Starks, 1906, Hepsetia pinguis mineri Nichols and Roemhild, 1951, Pranesus capricornensis Woodland, 1961, Pranesus maculatus Taylor, 1964, and Pranesus pinguis ruppelli Smith, 1965, are regarded as junior synonyms of Atherinomorus lacunosus. Atherinomorus pinguis is also widely distributed in the Indo-West Pacific, from East Africa to northern Australia and north to southern Japan.
Atherina pectoralis Valenciennes, 1835, is considered a junior synonym of Atherinomorus pinguis.
Supplementary material to this paper is available in electronic format at 相似文献
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The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae. 相似文献
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Jameson N Georgelis N Fouladbash E Martens S Hannah LC Lal S 《Plant molecular biology》2008,67(3):295-304
The mass movement of gene sequences by Helitrons has significantly contributed to the lack of gene collinearity reported between different maize inbred lines. However, Helitron captured-genes reported to date represent truncated versions of their progenitor genes. In this report, we provide evidence that maize CYP72A27-Zm gene represents a cytochrome P450 monooxygenase (P450) gene recently captured by a Helitron and transposed into an Opie-2 retroposon. The four exons of the CYP72A27 gene contained within the element contain a putative open reading frame (ORF) for 428 amino acid residues. We provide evidence that Helitron captured CYP72A27-Zm is transcribed. To identify the progenitor gene and the evolutionary time of capture, we searched the plant genome database and discovered other closely related CYP72A27-Zm genes in maize and grasses. Our analysis indicates that CYP72A27-Zm represents an almost complete copy of maize CYP72A26-Zm gene captured by a Helitron about 3.1 million years ago (mya). The Helitron-captured gene then duplicated twice, approximately 1.5-1.6 mya giving rise to CYP72A36-Zm and CYP72A37-Zm. These data provide evidence that Helitrons can capture and mobilize intact genes that are transcribed and potentially encode biologically relevant proteins. 相似文献
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Cassava (Manihot esculenta Crantz), though a major world crop with enormous potential, is very under studied. Little is known about its genome structure and organisation. Transposable elements have a key role in the evolution of genome structure, and can be used as important tools in applied genetics. This paper sets out to survey the diversity of members of three major classes of transposable element within the cassava genome and in relation to similar elements in other plants. Members of two classes of LTR-retrotransposons, Ty1/copia-like and Ty3/gypsy-like, and of Enhancer/Suppressor Mutator (En/Spm)-like transposons were isolated and characterised. Analyses revealed 59 families of Ty1/copia, 26 families of Ty3/gypsy retrotransposons, and 40 families of En/Spm in the cassava genome. In the comparative analyses, the predicted amino acid sequences for these transposon classes were compared with those of related elements from other plant species. These revealed that there were multiple lineages of Ty1/copia-like retrotransposons in the genome of cassava and suggested that vertical and horizontal transmission as the source of cassava Mecops may not be mutually exclusive. For the Ty3/gypsy elements network, two groups of cassava Megyps were evident including the Arabidopsis Athila lineage. However, cassava En/Spm-like elements (Meens) constituted a single group within a network of plant En/Spm-like elements. Hybridisation analysis supported the presence of transposons in the genome of cassava in medium (Ty3/gypsy and En/Spm) to high (Ty1/copia) copy numbers. Thus the cassava genome was shown to contain diverse members of three major classes of transposable element; however, the different classes exhibited contrasting evolutionary histories. 相似文献
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The genes encoding the biosynthesis of the dipeptide bacilysin and its antibiotic constituent anticapsin were isolated from several strains of Bacillus subtilis as well as B. amyloliquefaciens and B. pumilus. The ywfBCDEF genes of B. subtilis 168 were shown to carry the biosynthetic core functions and were renamed bacABCDE. Mutation of the bacD gene or transformation of the bacABC genes into a B. subtilis (ywfA-bacABCDE) deletion mutant led to the accumulation of anticapsin, which was fourfold higher after transformation of the bacABC genes into a bacD mutant. The genes bacD and bacE proved to encode the functions of amino acid ligation and self-protection to bacilysin, respectively. Amplification of the bacABCDE gene cluster in a bacAB gene-deficient host strain of B. amyloliquefaciens resulted in a tenfold bacilysin overproduction. Some host strains required distinct glucosamine and yeast extract supplements in order to prevent suicidal effects of the recombinant antibiotic production. The bac genes from different Bacillus species revealed the same arrangement and 72.6–88.6% of sequence identity. 相似文献
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The interaction between Shigella dysenteriae or Shigella sonnei and Acanthamoeba castellanii was studied by viable counts, gentamicin assay and electron microscopy. The result showed that Shigella dysenteriae or Shigella sonnei grew and survived in the presence of amoebae for more than 3 weeks. Gentamicin assay showed that the Shigella were viable inside the Acanthamoeba castellanii which was confirmed by electron microscopy that showed the Shigella localized in the cytoplasm of the Acanthamoeba castellanii. In conclusion, the relationship between Shigella dysenteriae and Shigella sonnei with Acanthamoeba castellanii is symbiotic, and accordingly free-living amoebae may serve as a transmission reservoir for Shigella in water. 相似文献
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Abstract
Numerous miniature inverted repeat transposable elements (MITEs) are present in the rice genome but their transposition mechanisms
are unknown. In this report, we present evidence that two novel MITE families may have arisen from Mutator-related transposable elements and thus may use a transposition mechanism similar to that of Mutator elements. Two families of novel MITEs, namely, MDM-1 and MDM-2, were identified by searching for MITEs nested with Kiddo, a previously identified MITE family. MDM-1 and MDM-2 bear hallmarks of Mutator elements, such as long terminal inverted repeats (LTIRs), 9-bp target-site duplications (TSDs), and putative transposase
binding sites. Strikingly, the MDM-1 family has a 9-bp terminus identical to that of a rice Mutator-like element (MULE-9) and the MDM-2 family has an 8-bp terminus identical to that of the maize autonomous Mutator element MuDR. A putative transposase homologous to MURA protein is identified for the MDM-2 family. Thus, these two novel MITE families, with a total copy number of several hundred in rice, are designated Mutator-derived MITEs (MDMs). Interestingly, sequence decay analysis of MDM families revealed a number of insertion site duplications (ISDs) in the alignment gaps, and widespread historical nesting
events are proposed to account for the existence of these ISDs. In addition to its value for discovering new MITEs, the nesting
analysis approach used in this study simultaneously identifies MITE insertion polymorphisms. 相似文献
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D. J. Goyder 《Kew Bulletin》2008,63(2):331-333
Summary
Funastrum rupicola Goyder, a new species of Apocynaceae: Asclepiadoideae from Bolivia, is described and illustrated. The conservation status of this species is assessed. 相似文献
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Clethra barbinervis (Ericales), Cucumis sativus, and Lycopersicon esculentum were grown in soils collected from six different vegetation sites (cedar, cypress, larch, red pine, bamboo grass, and Italian ryegrass), and morphology and colonization preference of arbuscular mycorrhizal (AM) fungi were investigated by microscopic observation and PCR detection. C. barbinervis consistently formed Paris-type AM throughout the sites. C. sativus formed both Arum- and Paris-type AM with high occurrence of Arum-type AM. L. esculentum also formed both Arum- and Paris-type AM but with high occurrence of Paris-type AM. AM diversity within the same plant species was different among the sites. Detected AM diversity from AM spores in different site soils did not consistently reflect AM fungal diversity seen in test plants. Detected families were different, depending on test plants grown even in the same soil. AM fungi belonging to Glomaceae were consistently detected from roots of all test plants throughout the sites. Almost all the families were detected from roots of C. barbinervis and L. esculentum. On the other hand, only two or three families of AM fungi (Archaeosporaceae and/or Paraglomaceae and Glomaceae) but not two other families (Acaulosporaceae and Gigasporaceae) were detected from roots of C. sativus, indicating strong colonization preference of AM fungi to C. sativus among test plants. This study demonstrated that host plant species strongly influenced the colonization preference of AM fungi in the roots. 相似文献
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Yi-Zhi Zhao 《Kew Bulletin》2008,63(2):345-346
Summary
Caragana aliensis a new species from Tibet, China, is described and illustrated. 相似文献
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A lab rearing technique was standardised for Apanteles taragamae Viereck (Hymenoptera: Braconidae), the early larval parasitoid of the coconut leaf-eating caterpillar, Opisina arenosella Walker on the alternate host Corcyra cephalonica Stainton (Lepidoptera: Pyralidae). The parasitoid took 23.3 ± 3.2 days to complete the egg to adult period. Adult longevity
for males and females was 15.3 ± 4.6 and 13.8 ± 4.6 days respectively. Fecundity was 14.8 ± 4.3 eggs per female. The percentage
parasitism was 60.6 ± 5.7 on the alternative host C. cephalonica and 64.6 ± 5.5 on the natural host O. arenosella. Eight- to ten-day-old caterpillars were the ideal stage of C. cephalonica for rearing A. taragamae. The results indicated the amenability of rearing A. taragamae on C. cephalonica in the laboratory. 相似文献