Eugenol as an efficacious anaesthetic for tambaqui, Colossoma macropomum (Cuvier)   总被引：1，自引：0，他引：1  

Rodrigo Roubach  Levy Carvalho Gomes  Flavio Augusto Leão Fonseca  & Adalberto Luiz Val 《Aquaculture Research》2005,36(11):1056-1061

Anaesthetics are important in fish culture to reduce handling stress and mortality. Eugenol is a promising anaesthetic because of its low cost, efficacy, safety margin for fish and lack of toxicity to humans. The goal of this study was to establish a protocol using eugenol as a fish anaesthetic for tambaqui Colossoma macropomum (Cuvier), and provide information for regulating authorities on establishing safety dosage protocols for its use. Juvenile and sub‐adult tambaqui were first individually exposed to doses of 35, 50, 65, 85, 100 or 135 mg L^?1 eugenol for 10 min. A second experiment examined the effect of the duration of exposure to eugenol on the time required for recovery and survival of tambaqui. A eugenol dose of 65 mg L^?1 was adequate to induce fish of both sizes into a surgical anaesthetic state, and recovery time was similar for dosages up to 100 mg L^?1. Exposure to the ideal dose (65 mg L^?1) for up to 30 min did not cause fish mortality. Fish blood glucose values were similar for all the tested eugenol doses as well as with the benzocaine control. The results show that eugenol is an efficient and safe anaesthetic for tambaqui.  相似文献   

Pushed to the edge: Environmental factors drive ecological responses of Aphanius fasciatus when in sympatry with invasive Gambusia holbrooki     

Flavio Monti  Massimiliano Marcelli  Paolo Fastelli  Niccolò Fattorini 《水产资源保护:海洋与淡水生态系统》2021,31(9):2547-2559

1. Interspecific competition may be particularly exacerbated when occurring between native and invasive alien species, with environmental conditions affecting drivers of natural selection and shaping spatio-temporal dynamics of animal communities. The effects of invaders are particularly evident in aquatic ecosystems with delicate and complex balances, such as Mediterranean coastal wetlands, characterized by unpredictable water flows and variable reserves. Understanding how native species respond to human-induced biological invasions is of paramount importance for planning management measures aiming at conservation purposes.
2. This study investigated whether the occurrence of a competing invader species resulted in changes in the ecological adaptations of a native species by comparing two coastal wetland fish species: the invasive eastern mosquitofish Gambusia holbrooki and the native Mediterranean killifish Aphanius fasciatus of conservation concern. The hypothesis was tested by sampling fishes at a coastal Ramsar site in central Italy, over 2 years.
3. Generalized linear mixed models were used to examine the occurrence of killifish in relation to water parameters and the presence of its putative competitor. The aim was to determine whether salinity, temperature, and water depth influenced the presence and abundance of killifish when in sympatry with mosquitofish.
4. Both the probability of presence and abundance of killifish increased with water salinity, but this increase was stronger when mosquitofish was present. Increasing water temperature and water depth were associated with a higher probability of presence and abundance of killifish respectively, although the effect of water depth was small. Both salinity and the presence of the invader acted synergistically in characterizing and shaping the population structure of the native species.
5. Living in the most extreme and stressed environments, the killifish is potentially at higher risk of extinction. These results highlight the importance of considering the interplay between multiple abiotic stressors combined with comparative data between invasive and native species as increasingly critical to aid in conservation efforts.

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Assessment under short-day conditions of genetic materials derived from three potato breeding strategies: 4x-4x (intra-Tuberosum), 4x-2x (FDR 2n-pollen), and 4x-4x (diplandrous tetraploid)     

J.A. Buso  F.A.S. Aragão  F.J.B. Reifschneider  L.S. Boiteux  S.J. Peloquin 《Euphytica》2002,126(3):437-446

Families and cultivars derived from three breeding strategies [the conventional 4x-4x (intra-Tuberosum), the interploid 4x (Tub)-2x (Phureja-haploid Tub), and 4x (Tub)-4x (diplandrous tetraploid-DTO)] were evaluated under short-day conditions in Brazil. Two 4x-4x (intra-Tub) cultivars (`Bintje' and `Delta') were used as standards. The 4x-2x (FDR) and 4x-4x (DTO) strategies were equivalent for all traits but they presented superior performance when compared to the 4x-4x (intra Tub) scheme(as a group) for total tuber yield (TTY), commercial yield (CY), and plant vigor (PV). No differences among breeding schemes were observed for three other traits: eye depth (ED), plant uniformity (PU), and haulm maturity (HM). As a group, the 4x-2x (FDR) and 4x-4x (DTO) strategies were similar to the two standard cultivar for all traits but HM. However, eight families [six 4x-2x (FDR) and two 4x-4x (DTO)] had significantly superior performance for TTY when compared with the standard cultivars. For CY, the best 4x-4x (DTO) and the best 4x-2x (FDR) families outyielded `Bintje' by161% and 128%, respectively. No major differences were observed between breeding schemes for TTY and CY when comparing families derived from one single cultivar (`Chiquita') as 4x female parent. However, superior families, based upon multi trait selection criteria, could be obtained only with the 2n-pollen-based strategies. It was possible to select high yielding 4x-2x (FDR) and 4x-4x (DTO) families with favorable trait combinations (e.g., high yielding with ED scores similar to the standards). Individual DTO clones selected within these families may represent outstanding parental materials for crosses with tropical-adapted commercial cultivars. This initial comparison of progenies and cultivars derived from these breeding strategies suggests that 4x-2x (FDR) and 4x-4x (DTO) schemes could be viable alternatives to the conventional 4x-4 × crosses also in tropical/subtropical areas of the world. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Spatial variability of salt-affected soils in the middle Ebro Valley (Spain) and implications in plant breeding for increased productivity     

R. Isla  R. Aragüés  A. Royo 《Euphytica》2003,130(3):325-334

Barley breeding programs have empirically selected for improving grain yield and quality. The objective of this study was to quantify genetic gains in yield in 2-rowed malting barley cultivars released from 1944to 1998 in Argentina, identifying the major physiological traits responsible for them. For this purpose, a field experiment was conducted in absence of biotic and abiotic stressful factors and with lodging being prevented mechanically. Until the 1970's,potential yield was maintained nearly constant at 5.25 mg ha^-1 and since then it increased at a rate of 41 kg ha^-1 year^-1. That bi-linear trend was closely related to the trend of averaged yields obtained by farmers. The contribution made by breeding yield potential to the total yield gains achieved by farmers was estimated in c. One third. Neither time to heading nor time to maturity were systematically modified by breeding. However, the partitioning of the developmental time was modified: time to achieve both maximum number of floret primordia and length of the jointing –heading period were increased with the year of release of the cultivars. The main component associated with yield was the number of grains per m², due to variations in number of spikes per m².Total and vegetative biomass at maturity increased with the year of release of the cultivars, at a rate of 45 and 19 kg ha^-1 year^-1, while both harvest index and stem height remained virtually unmodified. Differences in biomass at heading among cultivars were related to the improvement on the abilities to capture more radiation. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Positive supercoiling of mitotic DNA drives decatenation by topoisomerase II in eukaryotes     

Baxter J  Sen N  Martínez VL  De Carandini ME  Schvartzman JB  Diffley JF  Aragón L 《Science (New York, N.Y.)》2011,331(6022):1328-1332

DNA topoisomerase II completely removes DNA intertwining, or catenation, between sister chromatids before they are segregated during cell division. How this occurs throughout the genome is poorly understood. We demonstrate that in yeast, centromeric plasmids undergo a dramatic change in their topology as the cells pass through mitosis. This change is characterized by positive supercoiling of the DNA and requires mitotic spindles and the condensin factor Smc2. When mitotic positive supercoiling occurs on decatenated DNA, it is rapidly relaxed by topoisomerase II. However, when positive supercoiling takes place in catenated plasmid, topoisomerase II activity is directed toward decatenation of the molecules before relaxation. Thus, a topological change on DNA drives topoisomerase II to decatenate molecules during mitosis, potentially driving the full decatenation of the genome.  相似文献   

Anaphase onset before complete DNA replication with intact checkpoint responses     

Torres-Rosell J  De Piccoli G  Cordon-Preciado V  Farmer S  Jarmuz A  Machin F  Pasero P  Lisby M  Haber JE  Aragón L 《Science (New York, N.Y.)》2007,315(5817):1411-1415

Cellular checkpoints prevent mitosis in the presence of stalled replication forks. Whether checkpoints also ensure the completion of DNA replication before mitosis is unknown. Here, we show that in yeast smc5-smc6 mutants, which are related to cohesin and condensin, replication is delayed, most significantly at natural replication-impeding loci like the ribosomal DNA gene cluster. In the absence of Smc5-Smc6, chromosome nondisjunction occurs as a consequence of mitotic entry with unfinished replication despite intact checkpoint responses. Eliminating processes that obstruct replication fork progression restores the temporal uncoupling between replication and segregation in smc5-smc6 mutants. We propose that the completion of replication is not under the surveillance of known checkpoints.  相似文献   

Ehrlichiosis in anemic, thrombocytopenic, or tick-infested dogs from a hospital population in South Brazil     

Dagnone AS  de Morais HS  Vidotto MC  Jojima FS  Vidotto O 《Veterinary parasitology》2003,117(4):285-290

Ehrlichia canis has a worldwide distribution, but clinical manifestations may vary geographically. We selected 129 dogs to determine prevalence of ehrlichiosis in dogs with anemia, thrombocytopenia, or ticks presented to a Veterinary Teaching Hospital in South Brazil. Of the 129 dogs, 68 carried the brown dog tick (Rhipicephalus sanguineus), 61 had thrombocytopenia (platelet count <150,000/microl), and 19 had anemia (PCV < 22%). Twenty dogs fulfilled more than one inclusion criteria. Ehrlichiosis was diagnosed by positive amplification of ehrlichial DNA by PCR using primers ECC and ECB that amplify a sequence of the 16S rRNA gene. Presence of E. canis was confirmed by cleavage of the amplified DNA using endonucleases HaeIII and AvaI. Fourteen of 68 (21%) dogs with ticks had ehrlichiosis, whereas 12 of 61 (20%) dogs presented with thrombocytopenia and 4 of 19 (21%) anemic dogs had ehrlichiosis. Similar results were obtained in dogs with thrombocytopenia and anemia (one of eight positive) and in dogs with thrombocytopenia and ticks (two of seven positive). All four dogs with anemia and ticks, and the dog that fulfilled all inclusion criteria yield no amplification of ehrlichial DNA by PCR. Based on our results, one in each five dogs infested by the brown dog tick, with anemia or thrombocytopenia had ehrlichosis. Contrary to widespread believe, ehrlichiosis was not the main cause for thrombocytopenia in our region.  相似文献   

Serological and molecular evidence of hepatitis E virus in swine in Brazil     

dos Santos DR  Vitral CL  de Paula VS  Marchevsky RS  Lopes JF  Gaspar AM  Saddi TM  Júnior NC  Guimarães Fde R  Júnior JG  Ximenes LL  Souto FJ  Pinto MA 《Veterinary journal (London, England : 1997)》2009,182(3):474-480

Active hepatitis E virus (HEV) infections in two Brazilian swine herds were investigated. In study 1, 26 piglets born to five anti-HEV positive sows were monitored from birth to post-partum week 22. Serum samples were screened for the detection of anti-HEV antibodies and a nested RT-PCR used to examine the HEV genome. Passive transfer of immunity was confirmed. At week 22, 23/26 (88.4%) of the piglets had seroconverted. Genome amplification was achieved in a feces pool from one holding pen and in one serum sample, both from 13-week-old animals. Histology was suggestive of a potential HEV infection. In the second study, 47 piglets born to six anti-HEV-positive sows were monitored after weaning. Seroconversion was determined in eight animals at 6-8 weeks of age. HEV RNA was detected in two pools from a holding pen for 12-16-week-old animals. Brazilian isolates were classified as genotype 3. This is the first molecular evidence of HEV infection in Brazilian pig herds.  相似文献