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51.
Five hundred and thirty-six samples of honeycombs were examined in a laboratory in the years 1971-1974. In all the samples clinically determined as the foul brood, B. alvei was isolated as a pure culture, and enterococci, or both microorganisms were isolated in mixed form. Twenty-five strains of the isolated streptococci were analyzed microbiologically and biochemically; on the basis of their culture and biochemical characteristics five strains were designated as Streptococcus faecalis, 14 strains as Streptococcus faecalis var. liquefaciens, five strains as Streptococcus faecium and one strain as Streptococcus durans. After checking the used taxonomic key of the culture and biochemical classification of B. alvei it may be stated that the culture and biochemical characteristics are stable. The strains of B. alvei (very dried strains), which persisted in the dried slant meat-peptone agar, were viable under the laboratory conditions, which proves the high resistance of the spores to the environment. 相似文献
52.
Silliman BR van de Koppel J Bertness MD Stanton LE Mendelssohn IA 《Science (New York, N.Y.)》2005,310(5755):1803-1806
Salt marshes in the southeastern United States have recently experienced massive die-off, one of many examples of widespread degradation in marine and coastal ecosystems. Although intense drought is thought to be the primary cause of this die-off, we found snail grazing to be a major contributing factor. Survey of marsh die-off areas in three states revealed high-density fronts of snails on die-off edges at 11 of 12 sites. Exclusion experiments demonstrated that snails actively converted marshes to exposed mudflats. Salt addition and comparative field studies suggest that drought-induced stress and grazers acted synergistically and to varying degrees to cause initial plant death. After these disturbances, snail fronts formed on die-off edges and subsequently propagated through healthy marsh, leading to cascading vegetation loss. These results, combined with model analyses, reveal strong interactions between increasing climatic stress and grazer pressure, both potentially related to human environmental impacts, which amplify the likelihood and intensity of runaway collapse in these coastal systems. 相似文献
53.
Djerassi C Lewis AL Altheide TK Varki A Arden K Varki NM Peekna A 《Science (New York, N.Y.)》2005,307(5716):1720-1721
54.
By using as sources supersonic jets of hydrogen or helium containing small concentrations of heavier molecules we have been able to obtain molecular beams with kinetic energies of the heavy molecules well into the range above I electron volt. A variety of molecules have been successfully accelerated. Intensities of 10(16) to 10(17) heavy molecules per steradian-second have been achieved at these high energies. 相似文献
55.
56.
Felipe Farias Pereira da Câmara Barros Pedro Paulo Maia Teixeira Luciana Cristina Padilha-Nakaghi Ricardo Andres Ramirez Uscategui Marina Ragagnin Lima Victor José Correia Santos Kayan da Cunha Rossy Luísa Pucci Bueno Borges Marcia Rita Fernandes Machado Wilter Ricardo Russiano Vicente 《Reproduction in domestic animals》2020,55(4):442-447
We tested FSHp, eCG and FSHp + eCG to establish ovum pick-up (OPU) and in vitro maturation method in spotted paca. Eight healthy adult females were subjected to each of four treatments to stimulate ovarian follicular growth. All females were subjected to a hormonal protocol using a single dose of 45 mg of injectable progesterone and single intramuscular injection of 0.075 mg d-cloprostenol on day 6. Ovarian stimulation was carried out as follows: in Group TFE (FSHp and eCG), animals were treated with a single dose of 80 mg of FSHp and 200 IU of eCG intramuscularly on day 6 after the application of progesterone; in Group TF (FSHp), they were treated with a single dose of 80 mg of FSHp intramuscularly on day 6 after application of progesterone; in Group treatment eCG, they were treated with 200 IU of eCG intramuscularly on day 6 after application of progesterone; and in Group TC (saline solution), 1 ml of saline solution was administered to control does. The OPU was performed between 22 and 26 hr after gonadotropin treatments. All recovered oocytes were placed into maturation media and incubated for 24 hr. There were no differences among the mean number of observed follicles, aspirated follicles and oocytes recovered per treatment. Oocyte maturation rates did not differ among groups, except, TF and treatment eCG oocytes had greater maturation rates than TC oocytes. In this study, gonadotropin administration failed to superovulate treated does and increase oocyte retrieval efficiency. Despite the feasibility of the procedure, further studies are needed to develop and refine hormonal protocols for oocyte recovery and in vitro maturation in this species. 相似文献
57.
G. Rozas P. Rey M. D. Andres E. Rebolledo M. Aldegunde 《Fish physiology and biochemistry》1990,8(6):501-506
The levels of tryptophan (Try), 5-hydroxytryptamine (serotonin, 5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were determined
in the brain regions of rainbow trout (Oncorhynchus mykiss) by high performance liquid chromatography with electrochemical detection (HPLC-EC). Brain tryptophan concentrations varied
from 3.972 ± 357 ng/g cerebellum) to 8.841 ± 772 ng/g (hypothalamus). The 5-HT concentrations varied from 69 ± 7 ng/g (optic
tectum) to 573 ± 34 ng/g (hypothalamus). The concentrations of 5-HIAA varied from 29 ± 3 ng/g (medulla oblongata) to 68 ±
7 ng/g (hypothalamus). Total and free serum tryptophan levels were also determined; in adult rainbow trout 92% of the serum
tryptophan was observed to be free i.e., not protein-bound. 相似文献
58.
Sandra Metslaid Allan Sims Ahto Kangur Maris Hordo Kalev Jõgiste Andres Kiviste Pertti Hari 《Journal of Forest Research》2011,16(3):237-243
There is strong evidence that climate change alters tree growth in boreal forests. In Estonia, the analysis of ring measurements has been a common method to study growth changes. In this study, annual height growth data from dominant or co-dominant Scots pine (Pinus sylvestris L.) trees were used to develop a growth model for three forest generations. Stem analysis was applied and annual height growth was measured as the distance between whorls, as detected by branch knots of whorls on the split stem surface. Retrospective analysis of height growth produced comparative trends for three different age groups. Statistical analyses were used to estimate the impact of different factors on growth. Annual height growth was considered the best indicator for detecting possible trends in the growth potential of trees. Study results indicate that three generations (separated by time periods of 30–40 years) showed significant differences in growth patterns caused by shifts in climatic factors and management regimes (anthropogenic and natural disturbances). 相似文献
59.
Pelagic longlines are widely known to interact with several species of sea turtles, and there is an increasing concern about the by-catch of turtles in commercial fisheries and its impact on their populations. However, information on sea turtle by-catch in the South Atlantic Ocean is scarce, and there are no quantitative by-catch data available on olive ridleys for the Equatorial Eastern Atlantic. In this paper we analyze data collected by observers on board an Uruguayan long-liner targeting swordfish in two areas in the Equatorial Eastern Atlantic: off the Gulf of Guinea and north of Saint Helenaa Island. Specimens of Lepidochelys olivacea and Dermochelys coriacea were hooked or entangled in 26 longline sets. All registered interactions with olive ridleys took place off the The Gulf of Guinea, with captures ranging from 1 to 3 specimens in a single set. The captured specimens, though not measured directly, appeared to be juveniles. In addition, the examination of the stomach contents of one female mako shark showed dermal scutes, vertebrae and the complete head of a sea turtle identified as L. olivacea, allowing us to estimate its curved carapace length. In contrast, adult specimens of D. coriacea were caught in the two fishing areas. The capture of 10 individuals in a single set was recorded. Due to the high rate of sea turtle by-catch observed off the The Gulf of Guinea (1.02 ind/1000 hooks) conservation programs in the area should take into consideration the possible existence of a developmental and feeding area in this zone. Accordingly, longline fisheries in this area should be monitored and mitigation measures put in place to avoid or minimize damage to the pelagic phase of African populations of sea turtles. 相似文献
60.