Solvent-free oxidation of primary carbon-hydrogen bonds in toluene using Au-Pd alloy nanoparticles

Selective oxidation of primary carbon-hydrogen bonds with oxygen is of crucial importance for the sustainable exploitation of available feedstocks. To date, heterogeneous catalysts have either shown low activity and/or selectivity or have required activated oxygen donors. We report here that supported gold-palladium (Au-Pd) nanoparticles on carbon or TiO(2) are active for the oxidation of the primary carbon-hydrogen bonds in toluene and related molecules, giving high selectivities to benzyl benzoate under mild solvent-free conditions. Differences between the catalytic activity of the Au-Pd nanoparticles on carbon and TiO(2) supports are rationalized in terms of the particle/support wetting behavior and the availability of exposed corner/edge sites.     

Inheritance of resistance to Phytophthora infestans in two diploid Mexican solanum species

Inheritance of resistance to Phytophthora infestans in the diploid Mexican species S. bulbocastanum and S. verrucosum appears to be quantitative. In these species there seems to be no clear distinction between a hypersensitive reaction to infection and one indicating a high degree of partial resistance. Sibbing or selfing apparently improves the degree of resistance in the progeny over that of the parents. S. verrucosum, a self-compatible species which shows little or no inbreeding depression after selfing, has especial advantages as a genetic tool and as a source of blight resistance, over S. bulbocastanum and other diploids.Contribution No. 119, Canada Dept. of Agriculture Research Station, Fredericton, New Brunswick, Canada     

解偶联蛋白与动物的能量代谢*

 动物需要能量来维持生命活动,所需的能量主要来源于食物里的碳水化合物、脂肪和蛋白质。即使在体重平衡(非生产、生长状态)动物仍需要能量来维持体重、体温恒定及肌肉的基本活动。最新发现的线粒体内膜转运蛋白质,具有调节能量代谢的作用,它们的活动增加了动物的基础代谢率,这类蛋白质被称为解偶联蛋白(Uncoupling Proteins, UCPs)。UCPs作为质子通道驱散氧化呼吸时形成的H⁺梯度,降低了线粒体膜电位差ΔμH⁺, 从而增加呼吸产热, 阻止ATP的形成。目前已至少发现有5种UCPs(UCP1,UCP2,UCP3,UCP4 和UCP5),这个家族的蛋白质已经在人类、哺乳动物、禽类、鱼、真菌、甚至在植物不同组织的线粒体内膜上被发现。     

Evaluation of serial venous and arterial lactate concentrations in healthy anesthetized sheep undergoing ovariectomy

ObjectiveTo determine if lactate concentrations in jugular venous and auricular arterial blood differ in anesthetized sheep.Study designProspective, controlled experimental study.AnimalsTwelve healthy adult ewes, 4–7 years and weighing 62–77 kg.MethodsJugular venous blood was collected before anesthesia (PreO_v) for measurement of lactate concentration, packed cell volume and total protein. Ewes were administered a standard anesthesia protocol. Jugular venous (IntraO_v) and auricular arterial (IntraO_a) blood samples were obtained 40 minutes after induction of anesthesia, and again in recovery (PostO_v and PostO_a). An additional blood sample was drawn 6 weeks post-operatively from non-fasted sheep (NF_Lact). Lactate concentrations were compared among PreO_v, IntraO_v and IntraO_a, PostO_v and PostO_a, and between PreO_v and NF_Lact with paired t-test and repeated measure analyses of variance (anova) with PreO_v as a covariate (p = 0.05).ResultsIntraO_v lactate concentration had decreased from PreO_v There were significant differences between arterial and venous IntraO and PostO lactate concentrations. There was no significant difference between IntraO and PostO, or PreO_v and NF_Lact.Conclusions and clinical relevanceLactate concentrations were significantly lower in anesthetized sheep compared to non-anesthetized sheep. Lactate concentrations in venous blood were higher than in arterial blood. Therefore, anesthetic status and sampling site should be considered when interpreting lactate concentrations, and the sampling site should be consistent for repeated measurements.     

Longitudinal serological surveys of Atlantic salmon, Salmo salar L., using a rapid immunoperoxidase-based neutralization assay for salmonid alphavirus

Longitudinal serological surveys for salmon pancreas disease virus (SPDV), the causal agent of pancreas disease (PD), were conducted on multiple caged populations of Atlantic salmon, Salmo salar L., on two farms over a 77-week period (farm 1, freshwater and marine stages) and a 36-week period (farm 2, marine stage only), using a microtitre-based virus neutralization (VN) assay. Collected sera were also screened for viraemia with SPDV, and pancreas, heart and muscle tissues were examined for lesions consistent with PD. Outbreaks of PD occurred during the marine phase on both farms, as demonstrated by seroconversion, the isolation of virus and progressive histopathological changes consistent with a PD outbreak. All populations monitored showed a progressive increase in seroprevalence of 90-100%, typically accompanied by rises in geometric mean antibody titres. With the exception of one caged population, which showed a marked biphasic seroprevalence pattern, the seroprevalence figures in the remaining four monitored populations remained high (> or =70%) until the end of the study period. Peak VN titres of > or =1/1280 were detected on both farms. The results provide essential baseline information for the interpretation of SPDV VN serology results, and indicate that this methodology is suited to both the diagnosis and seroepidemiology of SPDV infections.     

Weakening macroalgal feedbacks through shading on degraded coral reefs

1. Extensive and dense macroalgal fields can compromise the ecosystem function of habitat mosaics on reefs owing to their limiting effect on patch connectivity. Macroalgae can maintain and increase their dominance with effective self-reinforcing feedback mechanisms. For example, macroalgae can form dense beds, supressing coral settlement and grazing by herbivores. This compromised ecosystem function can lead to major socioeconomic and ecological changes.
2. Dense macroalgal beds were shaded with submerged shade sails of two sizes and changes to the underlying benthos and feeding rates of herbivorous fishes were recorded. The shade sails reduced the algae's ability to photosynthesize by 29%. After 6 weeks, macroalgal cover was reduced by 24% under small sails and by 51% under large sails. Small shade sails reduced turf algal growth by 23%, while large sails reduced growth by 82%.
3. Three months after removal of the shade sails, algal beds had almost completely regrown. During this regrowth period, herbivore bites taken from the experiment's substrates were recorded, with grazing impact reducing significantly with time.
4. This study is the first to achieve macroalgal reduction via the alteration of the light regime. While macroalgae regrew in this relatively short-term experiment, shading may be a viable reef management approach that aims to maximize habitat mosaics on coral reefs, particularly if used in combination with other intervention methods.

     

A genome scan of a four-way tilapia cross supports the existence of a quantitative trait locus for cold tolerance on linkage group 23

A genome scan, searching for quantitative trait loci (QTL) for the traits cold tolerance and body weight in tilapia, was performed on a cross between a (Oreochromis niloticus×Sarotherodon galilaeus) male and a (O. mossambicus×O. aureus) female. Fifty‐four microsatellites and 23 amplified fragment length polymorphism (AFLP) primer combinations were genotyped and tested for marker–trait associations. Sex‐specific linkage maps were constructed from this data. Twenty‐three point‐wise significant marker–trait associations were found in the genome scan, and putative QTL were subsequently tested in another (On×Sg) × (Om×Oa) family. None of the putative QTL from the first experiment were significant in the second experiment. However, one microsatellite, UNH130, found to be associated to weight in the first experiment, was found to be strongly associated to cold tolerance in the second experiment. Since QTL for cold tolerance and body weight were recently found on the linkage group containing UNH130 (linkage group 23) in another study, this linkage group was investigated more closely using interval mapping. The results provide indications, but not conclusive evidence, of a QTL for cold tolerance on linkage group 23.