Structure,development and function of the branchial sieve of the common bream,Abramis brama,white bream,Blicca bjoerkna and roach,Rutilus rutilus

Synopsis The filter feeding organ of cyprinid fishes is the branchial sieve, which consists of a mesh formed by gill rakers and tiny channels on the gill arches. In order to establish its possible role during growth we measured the following morphological gill raker parameters over a range of sizes in three cyprinid fishes, bream, white bream and roach: inter raker distance, bony raker length, raker width, cushion length and channel width. At any given standard length common bream has the largest inter raker distance, roach the lowest and white bream is intermediate. In the comb model of filter feeding the inter raker distance is considered to be a direct measure of the mesh size and retention ability (= minimal size of prey that can be retained) of a filter. For the three species under study there is a conflict between the comb model and experimental data on particle retention. Lammens et al. (1987) found that common bream has a large retention ability whereas roach and white bream have a much smaller one. A new model, the channel model (Hoogenboezem et al. 1991) has been developed for common bream; in this model the lateral gill rakers can regulate the mesh size of the medial channels on the other side of the gill slit. The present data indicate that this model is not appropriate for white bream and roach. At any given standard length white bream and roach only reach 70% of the raker length of common bream, which means that in this model the gill slits should to be very narrow during filter feeding. The gill rakers consist of a bony raker and a fleshy cushion. The bony rakers have a rather long needle-like part outside the cushion in bream, but not in white bream and roach which have blunt gill rakers. Blunt gill rakers are not suited to reduce the diameter of the medial channels. The comb model seems more appropriate for white bream and roach, but doubts about the validity of this simple model remain. The sum of the areas of the medial channels is an approximation of the area through which water flows in the filter. This channel area therefore gives an impression of the capacity or flow rate of the filter. With this capacity estimation and an estimation of energy consumption we calculated an energy ratio of filter feeding. The energy ratio decreases with increasing standard length with an exponent close to the expected exponent of -0.40. The energy ratio is highest in bream, intermediate in white bream and lowest in roach.     

Changes in macromolecule syntheses under special consideration of UNA and the energy providing system in imbibing embryos of different agedagrostemma githago L. Seeds

Changes in macromolecule syntheses, especially RNA synthesis, and the energy providing system were investigated in seeds ofAgrostemma githago aged for different periods. In embryos of aged seeds all macromolecule syntheses start later and reach a lower level than young ones. It was found that the synthesis of rRNA in embryos of aged seeds is reduced whereas the synthesis of poly (A⁺) RNA in relation to the total RNA synthesis is highly increased as well as the amount of this RNA species with long poly (A) chains. The results are discussed in connection with the decreased protein synthesis and the reduced ATP content and ATP formation ability in embryos during the long time storage of seeds.     

Effects of learning experience on behaviour of the generalist parasitoid Sclerodermus pupariae to novel hosts

Massicus raddei Blessig (Coleoptera: Cerambycidae), also referred to as the oak long‐horned beetle (OLB), is a non‐natural host for the generalist parasitoid Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae). To determine whether this generalist parasitoid might be a suitable agent for the control of OLB, the adaptive learning experience of adult female parasitoids to OLB larvae was investigated in the laboratory. A Y‐tube olfactometer bioassay was used to examine the effects of adaptive learning experience on the foraging ability of parasitoids for OLB larvae. The results indicated that parasitoids were significantly attracted by the volatiles of ash bark, Fraxinus velutina, with emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) larvae and larval frass, after exposure to ash bark mixed with EAB larval frass (learning condition A). In contrast, after exposure to oak bark, Quercus liaotungensis, mixed with OLB larval frass (learning condition C), parasitoids showed significant preference for the volatiles of oak bark with OLB larvae and larval frass. On the basis of the results of no‐choice tests, we found that parasitoids exposed to learning condition C had greater paralysis efficiency and higher OLB larvae parasitism rates than those exposed to learning condition A or no experience. Furthermore, parasitoids fed on OLB larvae in learning condition C had significantly greater paralysis efficiency and higher OLB larvae parasitism rates than other parasitoids tested. Parasitoids fed on EAB larvae in learning condition A had the lowest paralysis efficiency and OLB larvae parasitism rates among the parasitoids tested. These findings suggested that adaptive learning significantly enhanced the ability of a generalist parasitoid to utilize a novel host. This may provide a new approach to controlling non‐natural hosts using generalist parasitoids.     

Improvement of antagonistic capability of Trichoderma harzianum by UV-Irradiation for management of Macrophomina phaseolina

Antagonistic capability of Trichoderma harzianum was improved through UV-irradiation. Four different type of mutants, T. harzianum - M_a (Th-M_a), T. harzianum - M_b(Th-M_b), T. harzianum - M_c (Th-M_c), T. harzianum - M_d (Th-M_d) of T. harzianum and the parent strain (Th-P) were selected for further studies. Th-M_a and Th-M_b showed more antagonistic capability against Macrophomina phaseolina than its parent strain Th-P in dual culture. Biochemical analysis of these four mutants and the parent strain showed that Th-M_a releases higher level of two lytic enzymes i.e. chitinases and cellulases and Th-M_b produces more β-1,3-glucanase activity than the parent strain. Culture filtrate of Th-M_a also showed antifungal properties. Study of the competitive saprophytic ability (CSA) of these four mutants and the parent strain were also made. Th-M_a exhibited higher CSA than the parental isolate while Th-M_d had less CSA than all other mutants and the parent strain of T. harzianum.     

Focus: Addiction: Relapse Prevention and the Five Rules of Recovery

There are four main ideas in relapse prevention. First, relapse is a gradual process with distinct stages. The goal of treatment is to help individuals recognize the early stages, in which the chances of success are greatest. Second, recovery is a process of personal growth with developmental milestones. Each stage of recovery has its own risks of relapse. Third, the main tools of relapse prevention are cognitive therapy and mind-body relaxation, which are used to develop healthy coping skills. Fourth, most relapses can be explained in terms of a few basic rules. Educating clients in these rules can help them focus on what is important: 1) change your life (recovery involves creating a new life where it is easier to not use); 2) be completely honest; 3) ask for help; 4) practice self-care; and 5) don’t bend the rules.     

Reduced calcium/calmodulin-dependent protein kinase II activity in the hippocampus is associated with impaired cognitive function in MPTP-treated mice

Parkinson's disease (PD) patients frequently reveal deficit in cognitive functions during the early stage in PD. The dopaminergic neurotoxin, MPTP-induced neurodegeneration causes an injury of the basal ganglia and is associated with PD-like behaviors. In this study, we demonstrated that deficits in cognitive functions in MPTP-treated mice were associated with reduced calcium/calmodulin-dependent protein kinase II (CaMKII) autophosphorylation and impaired long-term potentiation (LTP) induction in the hippocampal CA1 region. Mice were injected once a day for 5days with MPTP (25mg/kg i.p.). The impaired motor coordination was observed 1 or 2week after MPTP treatment as assessed by rota-rod and beam-walking tasks. In immunoblotting analyses, the levels of tyrosine hydroxylase protein and CaMKII autophosphorylation in the striatum were significantly decreased 1week after MPTP treatment. By contrast, deficits of cognitive functions were observed 3-4weeks after MPTP treatment as assessed by novel object recognition and passive avoidance tasks but not Y-maze task. Impaired LTP in the hippocampal CA1 region was also observed in MPTP-treated mice. Concomitant with impaired LTP induction, CaMKII autophosphorylation was significantly decreased 3weeks after MPTP treatment in the hippocampal CA1 region. Finally, the reduced CaMKII autophosphorylation was closely associated with reduced AMPA-type glutamate receptor subunit 1 (GluR1; Ser-831) phosphorylation in the hippocampal CA1 region of MPTP-treated mice. Taken together, decreased CaMKII activity with concomitant impaired LTP induction in the hippocampus likely account for the learning disability observed in MPTP-treated mice.     

湖南工程学院生物工程专业实践 教学模式创新与实践

分析生物工程专业人才需求的现状与发展前景,构建了以社会需求为导向,以实践课程体系为载体,以能力培养为主线,以学生科技创新活动和教师科研为驱动,项目研究与能力培养相结合的创新实践教学模式.实践表明,创新实践教学模式极大提高了学生的学习兴趣和教师的工作热情.     

Use of seedling progeny tests for genetical studies as part of a potato (Solanum tuberosum subsp. tuberosum) breeding programme

A diallel set of crosses, including selfs and some reciprocal crosses, was made between 15 parents chosen for their male fertility from those included in a tetraploid potato (Solanum tuberosum subsp. tuberosum) breeding programme at the Scottish Crop Research Institute. Seedling progeny tests were used to evaluate the progenies for non-race-specific resistance to late blight (Phytophthora infestans) in both foliage and tubers, quantitative resistance to the white potato cystnematode (PCN) (Globodera pallida) and the commercial worth of their tubers as judged by breeders' visual preference. No reciprocal differences were found. Comparisons of the selfs and crosses revealed inbreeding depression for breeders' preference, which varied among the parents from negligible to severe, whilst there were also statistically significant differences for foliage and tuber blight, but not for PCN. When the selfs were omitted from the combining ability analyses, large differences in general combining ability (GCA) were found for all four traits, and smaller differences in specific combining ability for tuber blight and breeders' preference. The only statistically significant correlation between GCAs for different traits was a favourable one of r = 0.56 between foliage and tuber resistance to late blight. It was concluded that prospects were good for simultaneously improving all four traits by multitrait genotypic recurrent selection.