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1.
The effect of temperature on the rate of oxygen consumption and heart rate has been investigated in the Red Sea, semi‐terrestrial crab, Ocypode saratan. The Q 10 values for both oxygen consumption and heart rate were often <2 and were relatively constant over a wide range of temperature. This suggests that O. saratan is well adapted for life in a high temperature environment. It was noted, however, that behavioural mechanisms were important in reducing the degree of temperature stress that could be experienced in the field. The rates of oxygen consumption of immersed crabs were significantly lower than those of crabs maintained in air at the same temperature. 相似文献
2.
Twelve new South American species of Loranthaceae ( Aetanthus, Cladocolea, Oryctanthus, and Struthanthus) and Viscaceae ( Dendrophthora and Phoradendron) are described and illustrated: Aetanthus trifolius, Cladocolea rostrifolia, Dendrophthora lanceolata, Dendrophthora rotundata, Dendrophthora tenuis, Dendrophthora werffii, Oryctanthus minor, Phoradendron pascoi, Phoradendron vasquezianum, Struthanthus apiculatus, Struthanthus schultesii, and Struthanthus sessiliflorus. Additionally, Cladocolea alternifolia, previously thought to be probably extinct, is reported to occur on Ilha Grande, just west of Rio de Janeiro, Brazil. 相似文献
3.
An integrated outdoor cultivation of two macroalgal species: Ulva rotundata (Chlorophyta) and Gracilariopsis longissima (Rhodophyta) was designed. The macroalgae were cultured in effluents from an intensive marine culture (growout phase) of
gilthead seabream Sparus aurata. The biomass evolution of the algal tanks followed a logistic curve, where the approach to the maximum stocking density of
seaweeds was governed by thalli self-shading, as nutrient limitation in the cultivation tank was unlikely. The maximum stocking
density of the system was approximately 27.8 g U. rotundata L −1 (16.7 Kg m −2) and 11.9 g G. longissima L −1 (7.12 Kg m −2). Yield was more than 3 times higher in U. rotundata than in G. longissima. Overall, U. rotundata removed a greater percentage of phosphate (8.9%) and total dissolved inorganic nitrogen (54%) flowing into the algal tanks
than G. longissima. The latter species biofiltered approximately 3.2% of phosphate and 17% of the total dissolved inorganic nitrogen input.
However, mean nutrient uptake rates on wet weight basis were usually higher in G. longissima than in U. rotundata. The production of total oxidised nitrogen in the algal tanks, considered as being the nitrification rate occurring on the
algal fronds by nitrifying bacteria, was less than half of the ammonium uptake by the macroalgae, suggesting that seaweeds
competed efficiently for ammonia against the nitrifyers. The biofiltration during a diel cycle showed that mean phosphate
biofiltration was lower than 4.5% in the two species whereas ammonium was biofiltered efficiently (up to 67%), especially
in U. rotundata. The metal and heavy metal content in the algal tissue at the end of the monitoring period suggested no metal contamination
of tissues so that both macroalgal species could be used in the food industry. The study reveals the value of ecological engineering
techniques in reducing the dissolved nutrient content in effluents from the fish farm, with the prospect of a better management
practises, based on integrated mariculture designs, being developed by the local farmers. 相似文献
4.
Quadricilia rotundata is a heterotrophic flagellate with four flagella. However, because this species has no clear morphological characteristics or molecular data affiliating it with any known group, Q. rotundata has been treated as a protist incertae sedis, for a long time. Here, we established a clonal culture of Q. rotundata and sequenced its 18S rDNA sequence. Molecular phylogenetic analysis successfully placed Q. rotundata in an environmental clade within Cercozoa, which contributes to expand the morphological and species diversity within Cercozoa. We also discuss morphological evolution within Cercozoa based on this finding. 相似文献
5.
Abstract Ornithonyssus bursa (Berlese) (Dermanyssidae) is found in nests and neotboxes and on nestlings of the starling ( Sturnus vulgaris L.), sometimes in large numbers, during the breeding season. During the non-breeding season the nestboxes and nest material are devoid of live mites. O. bursa overwinters ectoparasitically on starlings, and is present on approximately 25% of the population at the beginning of the breeding season. These nucleus populations build up rapidly in nest boxes during the breeding season. 相似文献
6.
Changes in biomass of several macroalgae [ Ulva rotundata Bliding; Gracilariopsis longissima (S. G. Gmel.) Steentoft, L. M. Irvine et Farnham; Ulva intestinalis L.; and Cladophora sp.] and marine plants ( Zostera noltii and Ruppia cirrhosa) growing naturally in earthen ponds of a fish farm (Acuinova, San Fernando, Southern Spain) were recorded during a year. The farm is mainly devoted to the culture of gilthered seabream ( Sparus aurata). The most conspicuous algal species thriving in the ponds was U. rotundata, which reached densities up to 600 g dry mass · m −2 and produced up to 20.45 g C · m −2 · d −1. Dissolved nutrients (phosphate and ammonium), tissue nutrient content, and growth rates of this species were estimated during 2001 and 2002. Evidence of natural biomitigation by U. rotundata when water circulates throughout the fish farm is presented. Due to the fish cultivation, both phosphate and ammonium increased as water circulated from the preculture ponds to the postculture ponds. As a consequence, U. rotundata tissue nitrogen (N) and phosphorus (P) increased from algae growing in preculture ponds to algae growing in the outflow channel, so that mean C:N:P ratio varied from 773:57:1 in preculture ponds to 567:64:1 in the outflow channel. Phosphorus limited growth of U. rotundata during the spring. As growth rates increased as a function of tissue P, data were fitted to the Droop equation. From this equation, the estimated maximal growth rate was 0.295 ± 0.041 d −1, the subsistence quota was 0.05 ± 0.01% P of dry mass, and the critical quota was 0.215% P of dry mass. The results suggest that management of the fish farm based on a large-scale integrated mariculture system of fish and macroalgae may increase the total ecological and economic benefits, both for the farm and for the environment. 相似文献
7.
The cultivated yam species Dioscorea rotundata (2 n=40) has been considered by most authors as a tetraploid species with a basic chromosome number of ten. In this paper, we analysed the segregation of two isozyme loci and six microsatellite markers in the progeny of a self-fertilised monoecious plant. For the eight markers, segregation patterns could be explained by only two genetic models: diploidy or tetraploidy with two null alleles. Given the nature of studied markers, the most parsimonious hypothesis was that the parental plant was diploid. These results, data from a diversity survey and results of other authors led to the conclusion that D. rotundata is a diploid species. 相似文献
8.
Diarrhetic shellfish poisoning has been a recurrent problem along the Brittany coast (France) since 1983. Okadaic acid (O.A.), the main toxin detected in mussels, is generally associated with the presence of Dinophysis cells in sea water. We report here the results of okadaic acid analyses by high performance liquid chromatography, on planktonic samples collected during the summer of 1991. D. sacculus, the major Dinophysis species, throughout this period, showed low okadaic acid content in raw extract, whereas toxic levels were 3- to 12-fold higher in sorted samples than in raw ones. A maximum O.A. concentration of 29.6 pg cell -1 was found in D. sacculus/D. cf. acuminata extract. Similarly, higher O.A. levels were noted in raw samples when these two species were associated. Generally speaking, variations in raw samples were similar to those in sorted samples. Nevertheless, when D. rotundata reached a concentration equal to that of D. sacculus in sorted samples, the O.A. level was lower. 相似文献
9.
Parasitoids are expected to have the ability to find, recognize, and perhaps to discern potential hosts that can best support the development of their progeny. Melittobia Westwood (Hymenoptera: Eulophidae) are gregarious ectoparasitoids, which primarily attack mud daubers (Hymenoptera: Sphecidae). How Melittobia females locate their host is not well known, but the process may involve host‐related chemical signals. In this study, we investigated the roles of host chemical cues and natal rearing effect in host recognition by Mel. digitata Dahms. In an olfactometer that contained prepupae of Trypoxylon politum Say (Hymenoptera: Sphecidae), Megachile rotundata (Fabricius) (Hymenoptera: Megachilidae), puparia of Neobellieria bullata (Parker) (Diptera: Sarcophagidae), empty or intact host cocoons, or nest mud, Mel. digitata females spent significantly more time in air fields that contained T. politum (prepupae + cocoon) and Meg. rotundata (prepupae + cocoon) than in N. bullata and control fields. Nest mud and natal host had no attraction for parasitoid host choice. Most first and last choices of Mel. digitata females in the olfactometer were not consistent, suggesting an initial random dispersion, although they responded positively towards hosts in cocoons. 相似文献
10.
Osmia cornifrons plays a major role in the pollination of orchards, but basic information on vitellogenin and oocyte development is limited. To better understand vitellogenin in hymenopteran insects, we cloned a cDNA encoding vitellogenin from the hornfaced bee O. cornifrons. Osmia cornifrons vitellogenin cDNA contains 5477 bp with an open reading frame of 1783 amino acid residues, and has a predicted molecular mass of approximately 200.21 kDa and a pI of 6.55. Osmia cornifrons vitellogenin possesses four consensus (RXXR/S) cleavage sites and has conserved DGXR and GL/ICG motifs in the C‐terminus. The deduced amino acid sequence of the O. cornifrons vitellogenin cDNA showed a 66% identity with Megachile rotundata, 53% to Apis mellifera, 51% to Bombus ignitus and 42%–30% with other hymenopteran insect vitellogenins. Phylogenetic analysis showed that O. cornifrons vitellogenin clustered with vitellogenins from Megachilidae, Apidae, Vespidae and Formicidae species but not with those from Pteromalidae, Aphelinidae or Ichneumonidae species. The expression profile of O. cornifrons vitellogenin mRNA during development revealed that O. cornifrons vitellogenin was first detected in the pupal stage and was continuously detected during the adult stage. Interestingly, O. cornifrons vitellogenin mRNA expression was low in mid‐diapause, then gradually increased beginning on day 3 of the newly emerged adult stage, and subsequently declined. These results suggest that the expression level of O. cornifrons vitellogenin mRNA is stage‐specific. 相似文献
11.
Coral reef fishes use a multitude of diverse feeding behaviours to increase their ability to successfully capture a wide range of prey. Here, this study reports a novel hunting behaviour in a coral reef fish, the titan triggerfish, Balistoides viridescens, where an individual was seen partially beaching itself while attempting to catch a Red Sea ghost crab, Ocypode saratan. This is the first report of this behaviour in the order Tetraodontiformes and represents an astonishing capability of this species to exploit food resources outside their typical assumed ecological niche. 相似文献
12.
A supplement to the recent revision of Omadius Laporte 1836 (Mawdsley 2006) is presented. Ten species are treated: Omadius radulifer Gorham 1876 species reinstated is removed from synonymy with O. obscuripennis (Gorham 1876); O. scapularis (Gorham 1876) new combination is transferred from Stigmatium Gray 1832; O. chapaensis Pic 1927, O. curticollis Pic 1933, O. diversipes Pic 1933, O. nigrohumeralis Pic 1926, O. paulonotatus Pic 1946 and O. rufithorax Pic 1933 are confirmed as belonging to Omadius; and O. alishanus Nakane 1996 (missed by Mawdsley) plus the recently described O. santo Gerstmeier & Schmidl 2007 are also added. All ten species are re-described and integrated into Mawdsley’s key. The biogeographic situation and the biodiversity of Omadius in the Indo-Australian region are briefly discussed. 相似文献
13.
A small thecate dinoflagellate was encountered during winter and spring in the phytoplankton community of a shallow, brackish and hypertrophic pond in the South of France. The abundance of material permitted its identification, using scanning electron microscopy, as Oblea rotunda Balech ex Sournia. However, morphological features showed some discrepancies with the typical characteristics of O. rotunda. Environmental hydrographic parameters in the pond were very different from marine ecosystems where O. rotunda is usually reported. In this polluted and alkaline pond, salinity was low, ranging from 1.1 to 6.2 p.s.u.; the maximum densities of O. rotunda (greater than 1?×?10 5 cells l ???1) were observed at temperatures around 13°C, after a Cylindrotheca closterium?–?Heterocapsa rotundata bloom in early spring. These two species and other abundant taxa of the phytoplankton had seasonal patterns that could explain the presence of O. rotunda, since they could have been a food for this heterotrophic species. As this population showed most of the morphological criteria of O. rotunda, but with some variability and a different ecology, it is better considered as a variant of the marine species, rather than as a new species. This study provides additional data on the ecological and morphological features of this poorly known small peridinioid species, previously only reported from open seas and oceans. 相似文献
14.
Abstract Fusarium oxysporum Schlecht and Botryodiplodia theobromae Pat., two important post-harvest pathogens of yam ( Dioscorea rotundata L.) tubers in storage were found to produce oxalic acid (OA) in vitro and in vivo. The rate of OA accumulation was proportional to fungal growth (cell mass) in Potato Dextrose liquid medium during 10 days incubation period. Further, simultaneous co-culturing of either of the fungi with Bacillus subtilis CM1 isolated from cowdung culturable microflora resulted in 92% reduction in OA accumulation compared with that in the culture of the individual fungus. The effect was more prominent in pH 5 – 6 than in pH 7 – 8. B. subtilis CM1 was capable of detoxifying OA and several proteins were detected in the culture filtrates when it was grown in peptone-mineral salt medium containing OA. SDS-PAGE analysis of 70% ammonium sulphate fraction of the culture filtrate exhibited the presence of a predominant 97 kDa protein. 相似文献
15.
Yam ( Dioscorea spp.) is a tuberous staple food crop of major importance in the sub-Saharan savannas of West Africa. Optimal yields commonly
are obtained only in the first year following slash-and-burn in the shifting cultivation systems. It appears that the yield
decline in subsequent years is not merely caused by soil nutrient depletion but might be due to a loss of the beneficial soil
microflora, including arbuscular mycorrhizal fungi (AMF), associated with tropical “tree-aspect” savannas and dry forests
that are the natural habitats of the wild relatives of yam. Our objective was to study the AMF communities of natural savannas
and adjacent yam fields in the Southern Guinea savanna of Benin. AMF were identified by morphotyping spores in the soil from
the field sites and in AMF trap cultures with Sorghum bicolor and yam ( Dioscorea rotundata and Dioscorea cayenensis) as bait plants. AMF species richness was higher in the savanna than in the yam-field soils (18–25 vs. 11–16 spp.), but similar
for both ecosystems (29–36 spp.) according to the observations in trap cultures. Inoculation of trap cultures with soil sampled
during the dry season led to high AMF root colonization, spore production, and species richness (overall 45 spp.) whereas
inoculation with wet-season soil was inefficient (two spp. only). The use of D. cayenensis and D. rotundata as baits yielded 28 and 29 AMF species, respectively, and S. bicolor 37 species. AMF root colonization, however, was higher in yam than in sorghum (70–95 vs. 11–20%). After 8 months of trap
culturing, the mycorrhizal yam had a higher tuber biomass than the nonmycorrhizal controls. The AMF actually colonizing D. rotundata roots in the field were also studied using a novel field sampling procedure for molecular analyses. Multiple phylotaxa were
detected that corresponded with the spore morphotypes observed. It is, therefore, likely that the legacy of indigenous AMF
from the natural savanna plays a crucial role for yam productivity, particularly in the low-input traditional farming systems
prevailing in West Africa. 相似文献
16.
It was suggested that the abnormally high N 2 O values found in 130,000–160,000 year-old Vostok ice core samples, characterized by high δ 15 N and low δ 18 O values, resulted from in situ microbial N 2 O production. To substantiate these observations we obtained new geochemical data from the last glacial period and showed the existence of additional small N 2 O anomalies. To test the hypothesis that microbial metabolism could contribute to these anomalies, we developed protocols for examining the ability of Nitrosomonas cryotolerans cells to produce N 2 O at subfreezing temperatures. Our results show that these model, frozen cultures produce N 2 O at temperatures as low as ?32°C. 相似文献
17.
Absence of resistance/tolerance against bacterial leaf blight (BLB), incited by Xanthomonas oryzae pv. oryzae, in famous basmati varieties is one of the main reason for BLB epidemic in Punjab in 2007–2008. For developing resistance against BLB, the response of 26 IRBB lines of IRRI including 10 near isogenic lines (NILs) and 16 gene pyramids carrying two to five resistance genes (Xa series) was evaluated against 61 indigenous Xoo isolates under artificial inoculation field conditions. None of the NILs or gene pyramid provides complete protection against all the isolates. However, Xa21 and xa13 were found resistant against the majority of Xoo isolates, followed by Xa14 and Xa7. Of the 16 gene pyramids used in this study, IRBB-54 (Xa5 + Xa21), IRBB-55 (Xa13 + Xa21) followed by IRBB-58 (Xa4 + Xa13 + Xa21) were found effective against the majority of the Xoo isolates. These resistance genes (individually and in combinations) can be incorporated for the improvement of basmati rice cultivars cultivated in Punjab province of Pakistan. Effectiveness of gene combination supports the strategy of pyramiding appropriate resistance genes. Newly identified resistant genes may also be evaluated for achieving broad spectrum resistance against more Xoo isolates of the area. 相似文献
18.
Key messageWe applied the phylogenomics to clarify the concept of rice species, aid in the identification and use of rice germplasms, and support rice biodiversity. AbstractRice (genus Oryza) is one of the most important crops in the world, supporting half of the world’s population. Breeding of high-yielding and quality cultivars relies on genetic resources from both cultivated and wild species, which are collected and maintained in seed banks. Unfortunately, numerous seeds are mislabeled due to taxonomic issues or misidentifications. Here, we applied the phylogenomics of 58 complete chloroplast genomes and two hypervariable nuclear genes to determine species identity in rice seeds. Twenty-one Oryza species were identified. Conspecific relationships were determined between O. glaberrima and O. barthii, O. glumipatula and O. longistaminata, O. grandiglumis and O. alta, O. meyeriana and O. granulata, O. minuta and O. malampuzhaensis, O. nivara and O. sativa subsp. indica, and O. sativa subsp. japonica and O. rufipogon. D and L genome types were not found and the H genome type was extinct. Importantly, we evaluated the performance of four conventional plant DNA barcodes (matK, rbcL, psbA-trnH, and ITS), six rice-specific chloroplast DNA barcodes (psaJ-rpl33, trnC-rpoB, rps16-trnQ, rpl22-rps19, trnK-matK, and ndhC-trnV), two rice-specific nuclear DNA barcodes (NP78 and R22), and a chloroplast genome super DNA barcode. The latter was the most reliable marker. The six rice-specific chloroplast barcodes revealed that 17% of the 53 seed accessions from rice seed banks or field collections were mislabeled. These results are expected to clarify the concept of rice species, aid in the identification and use of rice germplasms, and support rice biodiversity. 相似文献
19.
We report herein the first crystal structures of (4-carboxy-1,3-thiazolidin-2-yl)pentitols [2-(polyhydroxyalkyl)thiazolidine-4-carboxylic acids], condensation products of l-cysteine with d-galactose and d-mannose: 2-(d- galacto-pentahydroxypentyl)thiazolidine-4-carboxylic acid hydrate, Gal-Cys·H 2O ( 1), and 2-(d- manno-pentahydroxypentyl)thiazolidine-4-carboxylic acid hydrate, Man-Cys·H 2O ( 2). In 1 and 2 the compounds crystallize as zwitterions, with the carboxylic groups deprotonated and the thiazolidine N atoms protonated. The sugar moiety and carboxylate group are in a cis configuration relative to the thiazolidinium ring, which adopts different conformation: twisted ( T) on C β–S in 1, and S-puckered envelope ( E) in 2. The carbon chain of the galactosyl/mannosyl moiety remains in an extended zig-zag conformation. The orientation of the sugar O2 atom with respect to the thiazolidinium S and N atoms is trans–gauche in 1 and gauche–gauche in 2. The molecular conformation is stabilized by the intramolecular N–H?O Cys contacts in both 1 and 2 and by the additional N–H?O Man interaction in 2. The crystal packing of orthorhombic 1 and monoclinic 2 is determined mainly by N/O/C–H?O hydrogen bonds forming ribbons linked to each other by direct and water-mediated O/C–H?O/S contacts. 相似文献
20.
The seasonal variability in the extraction yield, physicochemical characteristics, and rheological properties of ulvan from two Ulva species contributing to Brittany “green tides” has been studied. These seaweeds were collected in the water column for Ulva armoricana Dion, de Reviers et Coat and on hard substrata for Ulva rotundata Bliding. The maximum ulvan extraction efficiency was not related to the maximum ulvan content in the seaweeds, but with the active growth period of the seaweeds. Ulvan chemical structure, macromolecular characteristics, and rheological properties were affected by both species and seasons. The proportion of high‐molecular‐weight ulvan was the major factor positively correlated with the gelling properties. Characteristics of ulvan from U. rotundata subjected to tides were more affected by seasons than ulvan from U. armoricana living in a more constant environment. These results point to several useful recommendations concerning Ulva sp. biomass collected with regard to ulvan characteristics and uses. 相似文献
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