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1.
Synopsis We investigated the inter-relationships between coral colony size, social group size, mating system, and patterns of sex allocation
in the pygmy coral croucher, Caracanthus unipinna (Caracanthidae), an obligate coral-dwelling fish. Histological examination of the gonads from all individuals in social groups
revealed that the predominant mating system was harem polygyny. However, both group size and mating system co-varied with
coral colony size, with pair forming and monogamy occurring on small corals and group forming and harem polygyny on large
corals. This species therefore displays mating system plasticity in response to varying habitat patch size. Within-group sexual
size dimorphism and individual gonad structure indicate that C. unipinna is also likely to be a protogynous hermaphrodite. These social and reproductive features of C. unipinna contrast with some other coral-dwelling fishes, which display a lack of social and mating system plasticity in response to
habitat patch size, and either bi-directional or protandrous sex change. Possible reasons for this dichotomy include differences
in spawning mode, parental care and levels of intrasexual aggression. 相似文献
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3.
Two taxa of the genus Pluteus, i.e., Pluteus magnus and Pluteus podospileus f. podospileus, are newly recorded from Japan. The macroscopic and microscopic features of these two species are described and illustrated. 相似文献
4.
Katsuya Ichinose Luis C. Forti Denis R. Pretto Gösta Nachman Jacobus J. Boomsma 《Ecological Research》2007,22(2):288-295
Logistic regression analysis was used to analyse sex allocation in a population of the leaf-cutting ant Acromyrmex
balzani occurring in a pasture in southern Brazil. The field sample consisted of 151 fungus-garden chambers (18 queenright and 133
queenless), belonging to 50 nests with three vertically stacked chambers per nest on average. Taking nest chamber as the unit
of analysis, seven predictor variables were considered: sampling date, chamber depth, chamber volume, weight of fungus garden,
presence of a queen, number of large workers, and number of small to medium workers. The population-level numerical proportion
of females was 0.548 and the inferred proportional energetic investment in females 0.672. The former was not significantly
different from 0.5 (P=0.168), but the latter was (P=0.0003). The proportional investment in females per fungus garden increased with the number of large workers present (P=0.0002) and decreased with the dry weight of the fungus garden (P=0.012). This implies that resource acquisition through foraging is likely to be a major proximate determinant of sex allocation.
The negative correlation between female bias and fungus garden weight might be due to developing adult females requiring more
food than males, but this hypothesis could not be confirmed by direct statistical evidence. 相似文献
5.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes. 相似文献
6.
Summary A taxonomic revision of the palm genus Podococcus (Arecaceae) is presented. Two species are recognised: P. barteri, a species relatively widespread in a coastal band from Nigeria to the D. R. Congo and P. acaulis, a species previously considered conspecific to P. barteri, almost exclusively confined to Gabon. The taxonomic history, morphology, distribution and conservation status of the genus
and each species are discussed 相似文献
7.
Noel H. Holmgren 《Brittonia》2018,70(1):115-139
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations. 相似文献
8.
Guimond N Bideshi DK Pinkerton AC Atkinson PW O'Brochta DA 《Molecular genetics and genomics : MGG》2003,268(6):779-790
Transposable elements are being developed as tools for genomics and for the manipulation of insect genotypes for the purposes of biological control. An understanding of their transposition behavior will facilitate the use of these elements. The behavior of an autonomous Hermes transposable element from Musca domestica in the soma and germ-line of Drosophila melanogaster was investigated using the method of transposon display. In the germ-line, Hermes transposed at a rate of approximately 0.03 jumps per element per generation. Within the soma Hermes exhibited markedly non-random patterns of integration. Certain regions of the genome were distinctly preferred over others as integration targets, while other regions were underrepresented among the integration sites used. One particular site accounted for 4.4% of the transpositions recovered in this experiment, all of which were located within a 2.5-kb region of the actin5C promoter. This region was also present within the Hermes element itself, suggesting that this clustering is an example of transposable element "homing". Clusters of integration sites were also observed near the original donor sites; these represent examples of local hopping. The information content (sequence specificity) of the 8-bp target site was low, and the consensus target site resembles that determined from plasmid-based integration assays. 相似文献
9.
Three mitosporic fungi, i.e., Ardhachandra cristaspora, Dicyma pulvinata, and Sibirina gamsii from basidiomata of Aphyllophorales (Basidiomycetes), are described and illustrated. These fungi have not been previously reported in Japan. 相似文献
10.
A species of the gobiid genus Cristatogobius from northeastern Australia is described as new. This species is distinguishable from other species of the genus in having
a higher number of scales in a longitudinal row and in a transverse row and a rounded caudal fin. In addition, there are differences
in coloration such as brown reticulation on the upper anterior part of body and a red pectoral fin. A species of Cristatogobius reported from S. Java, Indonesia, is also identified as this species.
Received: May 21, 2002 /Revised: November 15, 2002 / Accepted: December 16, 2002 相似文献
11.
Mycena cupulicola sp. nov. and M. adscendens var. carpophila, new to Japan, are described and illustrated. The former is characterized by having lageniform caulocystidia with a slightly thick-walled broadened base and no cheilocystidia. The latter is characterized by having a white pileus up to 1mm in diameter and narrowly conical caulocystidia. Mycena cryptomeriicola was confirmed to have inamyloid basoidiospores. 相似文献
12.
A genetic transformation system has been developed for callus cells of Crataegus
aronia using Agrobacterium
tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with
5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different
types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red
colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli
were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this
is the first time to report an Agrobacterium-mediated transformation system in Crataegus
aronia. 相似文献
13.
Sophie Marion de Procé Daniel L. Halligan Peter D. Keightley Brian Charlesworth 《Journal of molecular evolution》2009,69(6):601-611
Contrary to the classical view, a large amount of non-coding DNA seems to be selectively constrained in Drosophila and other
species. Here, using Drosophila miranda BAC sequences and the Drosophila pseudoobscura genome sequence, we aligned coding and non-coding sequences between D. pseudoobscura and D. miranda, and investigated their patterns of evolution. We found two patterns that have previously been observed in comparisons between
Drosophila melanogaster and its relatives. First, there is a negative correlation between intron divergence and intron length, suggesting that longer
non-coding sequences may contain more regulatory elements than shorter sequences. Our other main finding is a negative correlation
between the rate of non-synonymous substitutions (d
N) and codon usage bias (F
op), showing that fast-evolving genes have a lower codon usage bias, consistent with strong positive selection interfering with
weak selection for codon usage. 相似文献
14.
Evolutionary patterns of sequence divergence were analyzed in genes from the conifer genus Taxus (yew), encoding paclitaxel biosynthetic enzymes taxadiene synthase (TS) and 10-deacetylbaccatin III-10β-O-acetyltransferase
(DBAT). N-terminal fragments of TS, full-length DBAT and internal transcribed spacer (ITS) were amplified from 15 closely related Taxus species and sequenced. Premature stop codons were not found in TS and DBAT sequences. Codon usage bias was not found, suggesting that synonymous mutations are selectively neutral. TS and DBAT gene trees are not consistent with the ITS tree, where species formed monophyletic clades. In fact, for both genes, alleles
were sometimes shared across species and parallel amino acid substitutions were identified. While both TS and DBAT are, overall, under purifying selection, we identified a number of amino acids of TS under positive selection based on inference using maximum likelihood models. Positively selected amino acids in the N-terminal
region of TS suggest that this region might be more important for enzyme function than previously thought. Moreover, we identify
lineages with significantly elevated rates of amino acid substitution using a genetic algorithm. These findings demonstrate
that the pattern of adaptive paclitaxel biosynthetic enzyme evolution can be documented between closely related Taxus species, where species-specific taxane metabolism has evolved recently. 相似文献
15.
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
16.
Ferreira LQ Avelar KE Vieira JM de Paula GR Colombo AP Domingues RM Ferreira MC 《Current microbiology》2007,54(5):348-353
The Bacteroides genus, the most prevalent anaerobic bacteria of the intestinal tract, carries a plethora of the mobile elements, such as
plasmids and conjugative and mobilizable transposons, which are probably responsible for the spreading of resistance genes.
Production of β-lactamases is the most important resistance mechanism including cephalosporin resistance to β-lactam agents
in species of the Bacteroides fragilis group. In our previous study, the cfxA gene was detected in B. distasonis species, which encodes a clinically significant broad-spectrum β-lactamase responsible for widespread resistance to cefoxitin
and other β-lactams. Such gene has been associated with the mobilizable transposon Tn4555. Therefore, the aim of this study was to detect the association between the cfxA gene and the presence of transposon Tn4555 in 53 Bacteroides strains isolated in Rio de Janeiro, Brazil, by PCR assay. The cfxA gene was detected in 11 strains and the Tn4555 in 15. The transposon sequence revealed similarities of approximately 96% with the B. vulgatus sequence which has been deposited in GenBank. Hybridization assay was performed in attempt to detect the cfxA gene in the transposon. It was possible to associate the cfxA gene in 11 of 15 strains that harbored Tn4555. Among such strains, 9 presented the cfxA gene as well as Tn4555, but in 2 strains the cfxA gene was not detected by PCR assay. Our results confirm the involvement of Tn4555 in spreading the cfxA gene in Bacteroides species. 相似文献
17.
New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora:
Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii
,
Rumex densiflorus var. pycnanthus
,
R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage. 相似文献
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19.
Erin P. Riley 《International journal of primatology》2007,28(1):107-133
I examined how Sulawesi Tonkean macaques (Macaca tonkeana) respond in terms of their diet and activity patterns to anthropogenic habitat alteration in Lore Lindu National Park, Sulawesi,
Indonesia. Anthropogenic habitat alteration comprised clearing of forest for agriculture and small-scale forest product collection.
I quantified the diet and activity of 2 groups (CH and Anca), occupying habitats with different levels of alteration, via
scan sampling. Tree abundance, key food specific density, and fruit production were greater in the minimally altered habitat
(CH), substantiating the characterization of the group’s habitat as higher quality. For the group in the heavily altered habitat
(Anca), alternative foods, e.g., insects, fungus, young and mature leaves, shoots, and stems, accounted for a significantly
greater proportion of the diet. Dietary diversity is significantly lower in the Anca group, with 52% of their diet being palm
fruits from Arenga pinnata. The activity patterns of the Anca group—more time foraging, less time moving, and more time resting than the CH group—reflect
the lower resource availability in their habitat and their reliance on more alternative food items, coupled with their extremely
small group size (6–9 individuals). The group may be at the optimal size in which foraging efficiency is maximized for the
habitat, a response, in conjunction with dietary and behavioral flexibility, to alteration of their habitat. The results are
contextualized with respect to the conservation value of human-modified landscapes. 相似文献
20.
Summary Three closely affiliated species of Heterospathe Scheff. (H. elegans (Becc.) Becc., H. humilis Becc. and H. versteegiana Becc.) from New Guinea are revised. They are reduced to a single species which is divided into two subspecies, and the new
combination H. elegans subsp. humilis (Becc.) M. S. Trudgen & W. J. Baker is made. The subspecies can be readily distinguished by their growth habit. Epitypes
are designated for the three previously published names, as informative material on the habit is not included in the existing
type specimens. A new, potentially related species is described as H. pullenii M. S. Trudgen & W. J. Baker. 相似文献