首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
St Paul's Rocks are a remote group of islets, barely 400 m across, in the equatorial mid-Atlantic (o°55'N 29°21'W). The results of a primarily zoological survey of the Rocks, carried out in September 1979 by the Cambridge Expedition to Saint Paul's Rocks, are reported. In addition, earlier studies of the Rocks' biology are discussed in the light of recent research. The terrestrial fauna is dominated by three species of sea-bird and a land crab. Also reported from on land are a few species of insects, ticks and spiders, an endemic pseudoscorpion, and a centipede; the majority of these species are associated with the seabirds.
The islets are devoid of tracheophytes, bryophytes and lichens.
The marine ecology of the Rocks is discussed with respect to habitat. Five habitats are distinguished in the supralittoral and littoral zones; the fauna and to a limited extent the flora of each is described. Sublittorally the Rocks consist almost entirely of steep escarpments extending to 60 m depth and beyond. The shallow sublittoral (< 60 m deep) is divided into four habitats: (1) Palythoa zone; (2) Caulerpa zone; (3) sub- Cauferpa zone, and (4) areas of unstable substrates. The Palythoa zone occupies a band extending from the base of the littoral to a depth of c . 5m and is dominated by a mat-forming hexacoral, Palythoa caribaeorum. Below this zone to a depth of c . 33 m the rock faces are thickly invested by a species of green-alga, Caulerpa racemosa. At depth this Caulerpa dominated zone is succeeded by an invertebrate dominated community. Unstable substrates are represented by a few pockets of coarse sand and some patches of rubble. The communities in each of these habitats are described. A primarily taxonomic review of the deep-water fauna is also included. Finally, the influence of ocean currents on the zoogeographical relationships of the Rocks' fauna is briefly examined.  相似文献   

2.
Saint Peter and Saint Paul's Archipelago is a collection of 15 islets and rocks remotely located in the equatorial Atlantic Ocean. In this particular site, the present project intended to assess the biodiversity and biotechnological potential of bacteria from the actinomycete group. This study presents the first results of this assessment. From 21 sediment samples, 268 strains were isolated and codified as BRA followed by three numbers. Of those, 94 strains were grown in liquid media and submitted to chemical extractions with AcOEt (A), BuOH (B), and MeOH (M). A total of 224 extracts were screened for their cytotoxic activity and 41 were significantly active against HCT‐116 cancer cells. The obtained IC50 values ranged from 0.04 to 31.55 μg/ml. The HR‐LC/MS dereplication analysis of the active extracts showed the occurrence of several known anticancer compounds. Individual compounds, identified using HR‐MS combined with analysis of the AntiMarin database, included saliniketals A and B, piericidins A and C and glucopiericidin A, staurosporine, N‐methylstaurosporine, hydroxydimethyl‐staurosporine and N‐carbamoylstaurosporine, salinisporamycin A, and rifamycins S and B. BRA‐199, identified as Streptomyces sp., was submitted to bioassay‐guided fractionation, leading to isolation of the bioactive piericidins A and C, glucopiericidin, and three known diketopiperazines, cyclo(l ‐Phe‐trans‐4‐OH‐l ‐Pro), cyclo(l ‐Phe‐l ‐Pro), and cyclo(l ‐Trp‐l ‐Pro).  相似文献   

3.
4.
A biological survey of St. Paul's Rocks in the equatorial Atlantic Ocean   总被引:1,自引:0,他引:1  
In May 1971, an ornithological census was taken, and samples of soil and marine invertebrates collected, on St. Paul's Rocks-an isolated group of small islands in the equatorial Atlantic Ocean. Fish were caught nearby. Crabs (Grapsus grapsus) were abundant on the Rocks and rock pools contained anthozoa, polychaetes, Crustacea and gastropods–a marine invertebrate fauna apparently closely related to that of Brazil. Specimens of four species of fish were obtained including one of Holocentrum sanctipauli , a species endemic to the Rocks.
Protozoa, nematodes, bdelloid rotifers and cuticles of cryptostigmatid mites were found in the soil; most of the species identified were microbial feeders with a cosmopolitan distribution. The only terrestrial flora observed were green and blue-green algae and a nematode-predacious fungus, continuous sea-spray upon the Rocks preventing the growth of higher plants. Breeding populations of brown boobies and black and brown noddies were observed and counted. The presence of all life-cycle stages of the booby suggested that its breeding is aseasonal.  相似文献   

5.
Abstract. A small brown moth, first recorded from St. Paul's Rocks by Charles Darwin and then subsequently on five occasions, is described as a new species, Erechthias darwini , from adults of both sexes, pupae and larvae. Apparently endemic to the Rocks and occupying a habitat less than 2 ha in extent in the central Atlantic, it belongs to a group with a predominantly Indo-Pacific distribution. Its closest relative is a pantropical 'introduced species and its existence calls into question the assumption that this and several other Erechthiinae are recent introductions into Africa and the New World. larvae of the new species have been collected from seabird nests where they probably feed on seaweed. Eleven genera are synonymized with Erechthias and three new synonymies established within the genus.  相似文献   

6.
7.
8.
鳗鱼     
鳗鱼是硬骨鱼鳗Li目鱼类的总称。主要介绍了鳗鱼的生物多样性,利用和保护。  相似文献   

9.
10.
11.
12.
Polyamine concentrations have been determined at intervals in suspension cultures of Paul's Scarlet rose cells during a culture period of 2 weeks. The mean concentrations of the putrescine, spermidine and spermine in the cells of the inocula were respectively 73, 70 and 13 nmol/g fresh weight. Putrescine at fitst increased with a peak (160 nmol/g) after 6 h, declined to a minimum (14 nmol/g) after 2–3 days, increased to a second peak (180 nmol/g) after 5–6 days, and then declined slowly to the concentration of the inoculum (taken on day 14). Spermidine rose slowly (×2.6) to a broad peak over 3–6 days (180 nmol/g), then declined slowly to the concentration in the inoculum. Spermine showed a rapid increase to a peak (130 nmol/g) after 2–3 days, and then declined rapidly, reaching the inoculum concentration by day 6. In one experiment the three amines showed a minor peak at day 11. Changes in spermine and RNA contents appeared to be correlated. DNA content reached a peak after that of the RNA (day 3) and did not appear to be correlated with the content of putrescine or the polyamines.  相似文献   

13.
The eastern Caribbean island of Saint Lucia is now famous in parasitological history as the setting for a major programme of schistosomiasis control'. Perhaps less well-known are the island's effective control of many intestinal parasites, and elimination of malaria, such that the current patterns of mortality and other demographic indicators now resemble those of industrialized countries. More recently, the island has become the focus for another community-based health programme as the Caribbean region again comes to grips with Aedes aegypti and its recently imported relative, Aedes albopictus, important vectors of yellow fever and dengue viruses (see Box 1).  相似文献   

14.
15.
16.
17.
18.
19.
The relationships of placoderm fishes   总被引:1,自引:0,他引:1  
  相似文献   

20.
The skin surface of bony fishes   总被引:2,自引:0,他引:2  
Mary  Whitear 《Journal of Zoology》1970,160(4):437-454
The cuticle described by light microscopists on the skin of various fishes, has been studied by electron microscopy in several species of teleost and in two other actinopterygian fish. Thelcuticle consists of an external coating layer, probably of mucopolysaccharide, which is secreted from the surface epidermal cells, not from the goblet mucous cells. The thickness of the cuticle is commonly of the order of 1 μm. It is particularly well developed in Trigla , where its thickness may vary from a fraction of a micron up to 50 μm, on different parts of the same individual. The cuticle has been detected in species from diverse orders, and is probably a normal constituent of the skin of all bony fishes. It is frequently lost during histological preparation. The external coat continues over the apertures of taste-buds, and may be continuous with the secretion at the mouths of chloride secreting cells. The secretion of the cuticle is partly from, or through, the outer membrane of the epidermal cells, but there is some evidence that cytoplasmic inclusions in the surface epidermal cells are also involved. There is striking variation in the appearance of these inclusions in electron micrographs of different species, and in some cases in different parts of the same fish, notably in Blennius. Certain of the inclusions are membrane-bounded vesicles whose contents are more electron-dense after staining with phosphotungstic acid than with lead citrate. In other cases, the inclusions are electron-transparent vacuoles. The cuticle is briefly compared with similar structures in other aquatic animals.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号