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1.
One new endemic savanna plant species from Cuba,Polygala omissa sp. nov., is described. It is known only from the locality of Yaguramas (Cienfuegos province).  相似文献   

2.
The natural presence of Beauveria bassiana was determined (Balsamo) Vuillemin from insects with mycotic symptoms collected in leaves and in the stalks of sugar cane (Saccharum sp. hybrid) in Pinar del Río, Ciudad de la Habana, Habana, Matanzas, Villa Clara, Cienfuegos and Camagüey. The results obtained demonstrate the natural presence of the entomopathogen fungus in larvae and chrysalises of Diatraea saccharalis (Fabricius) and they suggest the basis for the strategy of biological control against this borer.  相似文献   

3.
This paper presents data obtained between 1983 and 1989 on concentration of heavy metals in sediments of five Cuban bays having different physical and geographical characteristics and differing degrees of anthropogenic activities. Data are normalized with respect to Al, Fe, and organic content and processed through statistical techniques of multivariate analysis. The degree of heavy metal pollution among the harbors decreases in the following order: Havana, Santiago de Cuba, Cienfuegos Matanzas, Cárdenas  相似文献   

4.
The condition of coral reefs in the Cuban Archipelago is poorly known. We aimed to analyse coral assemblages across 199 reef sites belonging to 12 localities. Crest and fore reefs were assessed using six metrics: species richness, density, coral cover, mortality, coral size and reef complexity. The condition of reefs varied across the archipelago from healthy to depleted reefs. The localities with best scores were Cienfuegos, Bahía de Cochinos and Cazones. These reefs have values of living coral cover (>20%) and complexity (>50?cm) similar to the best preserved Caribbean reefs. However, the majority of crest biotopes suffered important deterioration with old mortality of Acropora palmata populations and moderate coral cover (15%); although crest reefs still maintained their structural complexity. Despite moderate levels of coral cover in fore reefs (18%), their condition was alarming because 25% of the sites had cover below the recovery threshold of 10%, accumulated mortality and structural flattening. Compared with the 1980s, the species richness was roughly the same (42) for crest and fore reefs, although dominance has changed to widespread tolerant species. Coral reef assemblages varied at local and regional scales in similar magnitude, suggesting the combined effects of natural and anthropogenic drivers.  相似文献   

5.
Synopsis Sections of ovary from plains viscacha, cat, ferret, rabbit, rat, guinea-pig and roe deer have been histochemically processed to demonstrate acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in nervous and non-nervous tissue. The effects of different reproductive states on enzyme activity were observed in some animals. AChE-containing nerves were sparse in rabbit and rat but plentiful in cat and roe deer. Nerves containing BuChE were not detectable in ferret or guinea-pig and were rare in cat. Species variations in the activity and type of enzyme were also found in non-neuronal tissues. Some blood vessels in the ovaries of guinea-pig and viscacha contained AChE. No other species showed a reaction for AChE in non-neuronal stromal tissue but BuChE was present at this site in all animals except rat. Granulosa cells reacted for AChE only in cat and rabbit while luteal cells were reactive in cat, rabbit and roe deer. Some BuChE activity was present in granulosa and or luteal cells in all species except roe deer. In rat, BuChE activity in luteal cells increased during oregnaney and the early phase of pseudopregnancy. The difficulty of assigning a function to ovarian cholinesterases is discussed.  相似文献   

6.
SUMMARY. Opercular bones from 323 perch from the River Stour were used for age and back-calculated growth determinations. Annuli were formed during May at the beginning of the growth period. Growth was minimal from October to April. Female perch grew faster than males, and the growth rates of both sexes were higher than those observed in most other European waters. Spawning occurred during late April and early May; male gonads began development in August and had attained their maximum weight in September, but the ovaries developed gradually from August until April. Immature perch had an annual cycle of condition with a maximum in June-July and a minimum in December-January. The condition of mature males and females was affected by the gonad cycle. The fecundity of Stour perch is expressed by the formula: log egg number = 2.40 log length (mm) - 1.34.
Approximately 25% of males were mature at age I and all were mature at age II, whereas most females did not spawn until age III. Ephemeroptera nymphs and minnow fry constituted the bulk of the diet of 0-group perch; Ephemeroptera nymphs, minnow fry and Corixidae were the most numerous items in I group perch, whereas older perch contained Corixidae and a wider range of fish prey species, although minnows were the most numerous of these.  相似文献   

7.
Summary The pituitary gland of the flounder, Pleuronectes flesus, showed several unusual cytological features. Between the RPD and the PPD was a zone of cells that stained purple with Alcian blue—PAS—orange G. Many of these cells were apparently degenerating. In the PPD the strands and coils of presumptive STH cells showed a tremendous variation in both size and staining properties. In the PI there were two cell types, the PAS-positive one bordering the neurohypophysis. Around the periphery of the PI was a zone of chromophobic cells, and throughout the PI were numerous intracellular and extracellular acidophil spheres.No well defined ACTH cells were found in the RPD of the minnow (Phoxinus phoxinus). The Alcian blue—PAS—orange G technique distinguishes between blue TSH cells and purple GTH cells in the RPD and PPD. GTH cells from animals collected in the winter were vacuolated. The PI contained two cell types whose staining reactions and ultrastructure were extremely variable. Intra- and extra-cellular acidophil spheres were present.I should like to thank Dr. T. Kerr of the Zoology Department, Leeds University, for his help and encouragement, and Mr. J. Dingley of the Department of Zoology, Aberystwyth, for collecting the flounders.  相似文献   

8.
Isogenic Escherichia coli strains carrying single DNA-repair mutations were compared for their capacity for (i) the repair of X-ray-induced DNA double-strand breaks (DSB) as measured using neutral sucrose gradients; (ii) medium-dependent resistance, i.e., a recA-dependent X-ray survival phenomenon that correlates closely with the capacity for repairing DSB; and (iii) the growth medium-dependent, recA-dependent repair of X-ray-induced DNA single-strand breaks (SSB) as measured using alkaline sucrose gradients (about 80% of these SSB are actually parts of DSB). These three capacities were measured to quantitate more accurately the involvement of the various genes in the repair of DSB over a wide dose range. The mutations tested were grouped into five classes according to their effect on the repair of X-ray-induced DSB: (I) the recA, recB, recC, and lexA mutants were completely deficient; (II) the radB and recN mutants were about 90% deficient; (III) the recF and recJ mutants were about 70% deficient; (IV) the radA and uvrD mutants were about 30% deficient; and (V) the umuC mutant resembled the wild-type strains in its capacity for the repair of DSB.  相似文献   

9.
The primary objective of this study was to determine the reproductive structure of the adult green sturgeon population in the Rogue River. Green sturgeon were captured by gillnet in the lower 11.6–68.4 river kilometers in April to July 2000–2003 and September and October 2002–2003. Gonadal tissue, collected by biopsy, was processed histologically, blood was collected from the caudal vasculature, and fork length (FL) and total length (TL) (±0.5 cm) were measured for each individual. Sex steroids, testosterone (T), 11-ketotestosterone (11-KT), and estradiol-17β (E2), were measured by radioimmunoassay. Biological samples were collected from a total of 88 green sturgeon of which 37 females and 41 males were confirmed by histological analysis. Four gravid females, captured in the spring, were visually identified, and oocyte polarization index and ovarian follicle diameter indicated that these females were in spawning condition. Gonadal samples collected from six individuals did not contain gonial cells, hence the sex and stage of maturity in these individuals remains unknown. Of the 20 females captured in the spring, 1 was vitellogenic, 4 were post-vitellogenic, and 15 were post-ovulatory. Twenty-one females were captured in the fall of which 6 were pre-vitellogenic, 7 vitellogenic, and 8 post-ovulatory. Of the 16 males captured in the spring, 2 were pre-meiotic, 8 were ripe or actively spermiating, and 6 were post-spermiation. Twenty-five males were captured in the fall: 11 pre-meiotic males and 14 post-spermiation. The majority of green sturgeon captured in the Rogue River were reproductively active or had recently spawned indicating the importance of this river for the preservation of green sturgeon.  相似文献   

10.
The helminth parasites of the greater kudu from the Kruger National Park (KNP), South Africa, and the Etosha National Park (ENP), Namibia, were examined to determine the major patterns of spatial and demographic variation in community structure and to evaluate nonrandomness in parasite community assembly. Nonmetric multidimensional scaling ordination procedures were used to test for differences in parasite community composition between hosts of the 2 parks and between hosts of different demographic groups within KNP. Infracommunities within KNP were also examined for patterns of nonrandomness using 2 null models, i.e., nestedness and species co-occurrence. Infracommunities of KNP and ENP were significantly different from each other, as were infracommunities of different host demographic groups within KNP. Parasite species in the greater kudu from KNP displayed significant levels of nestedness and were found to co-occur less frequently than expected by chance; however, this lack of co-occurrence was significant only when all demographic groups were considered. When restricted to any particular age class, co-occurrence patterns could not be distinguished from random. Overall, these data suggest that biogeography and host demographics are important factors in determining community organization of helminth parasites in the greater kudu.  相似文献   

11.
Abstract. The role of houseflies as agents in the spread of bacterial diseases has been thoroughly investigated, yet the fate of bacteria ingested by flies has not. We examined the physical location of the bacterial enteropathogen Aeromonas caviae in the midgut of laboratory‐reared adult houseflies. Food ingested by houseflies was separated from the midgut epithelium by a double‐layered peritrophic matrix (PM). The inner PM intimately enveloped the food as fecal pellets (food boluses), while the outer PM appeared as a long continuous tube. In flies fed a suspension of A. caviae, live bacteria were not observed within the inner PM, but were compartmentalized between folds of the PM in the inter‐PM space. Similar observations were made for flies fed a suspension of Serratia liquefaciens and for highly contaminated feral flies. Isolates of both A. caviae and S. liquefaciens were chitinolytic (as demonstrated by clearing zones on chitin agar), but the potential role of bacterial enzymes in the alteration of PM morphology or formation needs further investigation.  相似文献   

12.
The Alaska skate, Bathyraja parmifera, is the most abundant species of skate on the eastern Bering Sea shelf, accounting for over 90% of total skate biomass. However, little is known regarding the life history of this species despite its common occurrence as bycatch in several Bering Sea fisheries. This is the first study to focus on the age and growth of B. parmifera. From 2003 to 2005, more than one thousand specimens were collected by fisheries observers and on scientific groundfish surveys. Annual banding patterns in more than 500 thin sections of vertebral centra were examined for age determination. Caudal thorns were tested as a potentially non-lethal ageing structure. Annual band pair deposition was verified through edge and marginal increment analyses. A three-parameter von Bertalanffy growth function and a Gompertz growth function were fit to observed length-at-age data. Both models provided significant fits, although the Gompertz function best described the overall pattern of growth in both males and females, based upon statistical criteria and parameter estimates. Age and size at 50% maturity were 9 years and 92 cm TL for males and 10 years and 93 cm TL for females. The maximum observed ages for males and females were 15 years and 17 years, respectively. Estimates of natural mortality (M) ranged from 0.14 to 0.28, and were based on published relationships between M and longevity, age at maturity, and the von Bertalanffy growth coefficient. Due to these life history characteristics and a lack of long-term species-specific stock data, a conservative management approach would be appropriate for B. parmifera.  相似文献   

13.
Synopsis Two species ofGasterosteus were collected from the surface waters of 48 stations in the Bay of Fundy from 1979–1982. Densities varied widely according to locality and time of year (range: 1 fish 0.2 m–2 to 1 fish 26.3 m–2 of sea surface) but peaked within 30 km of the New Brunswick/Maine coast in July and August. A few adults were caught as far as 100 km from the coast in winter. Guts ofG. wheatlandi were significantly fuller (63.3 ± 0.6%) than those ofG. aculeatus (44.6 ± 0.1%) but there were no differences between male and female guts within species. Quantitatively, gut contents were very similar between species, consisting primarily of (99.4%): calanoid copepods (Centropages typicus Kroyer andEurytemora cfamericana Williams), copepod nauplii, cladocerans (Podon leuckarti Sars andP. polyphemoides Leuckart) and planktonic eggs (in decreasing order of importance).Gasterosteus wheatlandi ate significantly more calanoids thanG. aculeatus but all other prey types were eaten in similar amounts. Within species, there were no differences in the numbers of each prey type eaten over time. The most abundant calanoid species caught alongside the fishes in the sampling nets did not occur in the sticklebacks' diets; probably they were too large to be ingested.Gasterosteus aculeatus bred in inshore, brackish water ponds in late April. By late July most juveniles had migrated out into the Bay but a few remained until early September.Gasterosteus wheatlandi bred later in the brackish water ponds (late May) and juveniles began migrating into the Bay in early August; a few remained in the ponds until early September. Adults were found in the Bay alongside juveniles suggesting that individuals of both species may survive for a second year. In both species, growth rates of juveniles were greater in brackish water than in the sea.  相似文献   

14.
Carassius RFamide (C-RFa) is a novel peptide found in the brain of the Japanese crucian carp. It has been demonstrated that mRNA of C-RFa is present in the telencephalon, optic tectum, medulla oblongata, and proximal half of the eyeball in abundance. Immunohistochemical methods were employed to elucidate the distribution of the peptide in the brain of the goldfish (Carassius auratus) in detail. C-RFaimmunoreactive perikarya were observed in the olfactory bulb, the area ventralis telencephali pars dorsalis and lateralis, nucleus preopticus, nucleus preopticus periventricularis, nucleus lateralis tuberis pars posterioris, nucleus posterioris periventricularis, nucleus ventromedialis thalami, nucleus posterioris thalami, nucleus anterior tuberis, the oculomotor nucleus, nucleus reticularis superior and inferior, facial lobe, and vagal lobe. C-RFa immunoreactive fibers and nerve endings were present in the olfactory bulb, olfactory tract, area dorsalis telencephali pars centralis and medialis, area ventralis telencephali, midbrain tegmentum, diencephalon, medulla oblongata and pituitary. However, in the optic tectum the immunopositive perikarya and fibers were less abundant. Based on these results, some possible functions of C-RFa in the nervous system were discussed.  相似文献   

15.
Periphyton samples were collected at 15 sites in the Middle Fork of the Salmon River drainage basin, Idaho, USA to test certain principles of the River Continuum Concept (RCC) and to characterize the diatom communities. The standing crop of chlorophyll a increased from 2nd to 4th order streams, peaked in the 5th order stream, and declined in higher orders. These data support the RCC predictions except that peak values were reached somewhat earlier, in terms of stream order, because of the lack of shading in these streams. Also, downstream decreases were not completely attributable to increasing turbidity and decreasing benthic productivity, and may be partially related to discharge. The number of scraping invertebrates was positively correlated with the standing crop og periphyton (AFDM, not chlorophyll a); this, too, supports the predictions of the RCC. One hundred forty-five species of diatoms were identified and the system is characterized by an Achnanthes minutissima – Fragilaria pinnata - Navicula seminulum – Cocconeis placentula community.  相似文献   

16.
The age of the Ajime-loach,Niwaella delicata (a species endemic to Japan), was determined from the number of concentric rings appearing on the cross-sectional surface of the erectile spine (peculiar to Cobitidae). The ages of loaches caught in the Yura River, Kyoto, were determined and growth rates for each sex estimated. It was found that size dimorphism in this species was due to different growth patterns between the sexes, 2.5 years old males being larger than females and usually sexually mature, unlike the latter. Females older than 3.5 years were sexually mature and larger than males of equivalent age.  相似文献   

17.
Mosquito collections were carried out on microfilaraemic dogs, positive for Dirofilaria sp., for 18 consecutive nights in the coastal town of Celestún, Yucatan, southeast Mexico, during the rainy season (August) of 2007. A total of 292 female mosquitoes representing 12 species of dipteran Culicidae were collected: Anopheles albimanus (Wiedemann); Anopheles crucians (Wiedemann); Anopheles pseudopunctipennis (Theobald); Culex coronator (Dyar & Knab); Culex interrogator (Dyar & Knab); Culex nigripalpus (Theobald); Culex quinquefasciatus (Say); Culex salinarius (Coquillett); Aedes aegypti (Linnaeus); Aedes scapularis (Rondani); Aedes sollicitans (Walker), and Aedes taeniorhynchus (Wiedemann). Aedes taeniorhynchus and Cx. quinquefasciatus were the species found most commonly feeding on the dogs. Filarial nematodes were observed by microscopy in nine of the mosquito species collected; however, third‐instar larvae were only observed in Ae. taeniorhynchus and An. crucians. Of 76 Ae. taeniorhynchus specimens found positive for Dirofilaria sp. by dissection, 14 were confirmed to be positive for Dirofilaria immitis (Leidy) by polymerase chain reaction (PCR). The resulting infection rate for D. immitis confirmed by PCR (6.2%) is higher than any infection rate for Ae. taeniorhynchus previously reported from the Americas.  相似文献   

18.
The mycoflora of hair of 111 cows, donkeys, rabbits, cats, and dogs were analysed and the frequency of occurrence and the relative importance value of the different fungal species isolated were calculated. Total numbers of species 56, 45, 48, 23, and 11 were recovered from cows, donkeys, rabbits, cats, and dogs respectively. The majority of the keratinophilic fungi isolated were either well-known mycotic agents or have been recovered from various animal and human lesions. These comprised 87.8%, 66.7%, 61.4%, 59.3%, and 55.2% of the hair mycoflora in cats, dogs, rabbis, cows, and donkeys respectively. Seven species of dermatophytes were isolated: Trichophyton mentagrophytes, T. verrucosum, Microsporum gypseum, M. nanum, T. ajelloi, and M. canis. Cats harboured the largest number of dermatophytes (5 species), followed by cows (4 spp), rabbits (3 spp), and donkeys and dogs (1 sp). The role of these animals in the persistence and transmission of pathogenic fungi is discussed.  相似文献   

19.
Commercial formulations of the pesticides: Guthion (azinphos methyl), Sencor (metribuzin), Lorox (linuron), Reglone (diquat), Daconil (chlorothalonil) and Admire (imidacloprid) were studied for their genotoxicity by 32P-postlabeling. Metabolites of the pesticides were obtained enzymatically using arochlor induced rat liver S9 fraction, in an NADPH generating system. The resulting metabolites were reacted with calf thymus DNA and the DNA was analyzed for presence of adducts by either the nuclease P1 or butanol enrichment. Nuclease P1 enrichment resulted in adducts for all the pesticides. Compared to the level of adducts in control DNA, the levels in pesticide-treated DNA were higher for all the pesticides, except Daconil. The increase in adduct numbers for pesticide-treated DNAs ranged from 4.9-12.4 times the control-DNA indicating pesticide genotoxicity in this in vitro system. Enrichment using butanol extraction gave three adducts unique to Sencor-DNA. These adducts were different from those obtained with nuclease P1 enrichment of the same. B()P was the positive control for the in vitro metabolism, and two adduct enrichment procedures: nuclease P1 digestion and butanol extraction.  相似文献   

20.
Abstract

Morphological features of the circulating blood cells of an adult female tuatara are described and illustrated. Mitosis in circulating erythrocytes and the occurrence of an intraerythrocytic haemogregarine parasite are noted. The packed cell volume (haematocrit) was 35%. There were about 310 000 erythrocytes and 7200 leucocytes per mm3 of blood. The lymphocyte was the predominant leucocyte, followed by the eosinophil, monocyte, neutrophil, and basophil. The eosinophils and neutrophils reacted positively to acid phosphatase and peroxidase; the neutrophils were also esterase positive, and all three granulocytes were PAS positive. Haemoglobin, plasma protein, glucose, sodium, potassium, cholesterol, and triglyceride levels were determined. The primitive nature of the tuatara is reflected in the morphological. mensural, and biochemical data presented.  相似文献   

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