Relations between biological diversity in continental waterbodies and their morphometry and water mineralization

The number of phytoplankton, zooplankton, and macrobenthos species was studied in continental lakes of diverse origin, geographical position, and hydrochemical (water mineralization) and morphological (area and capacity) characteristics. It is shown that the diversity of benthos communities depends on mineralization, area, and capacity of the waterbody, the dependence on area and mineralization being stronger than the dependence on capacity. Zooplankton community diversity depends on water mineralization and, to a very small extent, on waterbody area. The number of phytoplankton species in a lake is not strictly determined by morphometric characteristics and water mineralization. This number is to a greater extent dependent on other factors (e.g., light, nutrients, etc.). The largest number of benthos and plankton species was observed in waterbodies with water mineralization around 0.4 g/l. Increase in mineralization leads not only to decrease in species number, but also to simplification of community structure in plankton and bottom organisms, which is reflected by the Shannon index of diversity decreasing accordingly. The studied relations show wide dispersal in the number of species that can result, beside other factors unaccounted for, from the uneven reliability of the identifications and recordings of plankton and benthos species due to the different proficiency level of experts in taxonomy and systematics.     

Cosmine resorption structures on three osteolepid jaws and their biological significance

Cosmine resorption structures on three osteolepid jaws provide evidence for two different types of resorption process, one superficial and one initially internal. The superficial process starts in the pore canal openings. and the internal probably in the dentine pulp cavities or other cavities within the cosminc. Different stages of the superficial process that have previously not been recorded can he seen. Their positions show that superficial resorption may start in a few centers, from which it may spread in all directions but at different rates in different directions. There is no observable correspondence between the occurrence of resorption and the growth of the dermal bones along their sutures. Thus, the primary reason for resorption is not to allow marginal growth of the dermal bones. □ Cosmine resorption, osteolepids, Middle Devonian.     

外来入侵杂草传统生物防治的生态风险及其防范对策

长期大量实践说明,引进天敌防治外来入侵杂草的传统生物防治方法是治理外来入侵杂草的一条切实可行的有效途径,但对其潜在的生态风险——对本土生物的直接或间接不良影响不容忽视。利用传统评价方法预测候选天敌的生态风险存在缺陷,主要表现在：（1）寄主专一性测定过分依赖室内进行的生理寄主范围测定结果,对生态寄主范围（实际寄主范围）问题重视不够,后者指在新环境中的一系列物理和生物条件下的寄主利用预测;（2）在生理寄主范围测定中,过分依赖完成生长发育的可能性,对行为、遗传性状以及系统发育关系重视不够;（3）在风险评估中,过多强调对经济作物的风险,而对自然生态系统的风险重视不够。对此,建议：（1）鼓励对已释放的天敌进行回顾性跟踪研究,从而为杂草生物防治实践提供生态学理论支撑;（2）在运用生物防治手段对付外来入侵杂草实践中,建议采用“有害推论”的预防性原则,以避免在面临入侵生物重大威胁时草率做出释放天敌的决策;（3）在评估候选天敌风险中重视生态效应的风险评估。     

Post-translational modifications and their biological functions: proteomic analysis and systematic approaches

Recently produced information on post-translational modifications makes it possible to interpret their biological regulation with new insights. Various protein modifications finely tune the cellular functions of each protein. Understanding the relationship between post-translational modifications and functional changes ("post-translatomics") is another enormous project, not unlike the human genome project. Proteomics, combined with separation technology and mass spectrometry, makes it possible to dissect and characterize the individual parts of post-translational modifications and provide a systemic analysis. Systemic analysis of post-translational modifications in various signaling pathways has been applied to illustrate the kinetics of modifications. Availability will advance new technologies that improve sensitivity and peptide coverage. The progress of "post-translatomics", novel analytical technologies that are rapidly emerging, offer a great potential for determining the details of the modification sites.     

不同森林恢复方式对我国南方红壤区土壤质量的影响

2008-2009年在我国南方红壤区,研究了3种典型森林恢复方式(自然恢复的天然次生林、人工恢复的本地种马尾松人工林和引进种湿地松人工林)对林地土壤质量的影响.结果表明:天然次生林的土壤含水量、土壤容重、土壤粒径构成、土壤全碳、全氮、全磷、有机碳、速效氮、速效磷、速效钾含量均优于两种人工林.综合土壤物理性状、化学性状和微生物性状得到土壤质量综合指数.天然次生林土壤的综合质量指数(1.20+0.10)显著高于马尾松人工林(0.59±0.03)和湿地松人工林(0.59±0.06),而两种人工林之间差异不显著.在我国南方红壤区,自然恢复的天然次生林土壤质量优于人工恢复的马尾松林和湿地松林.     

The typology of temporary waterbodies and the influence of their parameters on the crustacean species composition of zooplankton

The typology of temporary waterbodies in Saratov oblast has developed with a similarity in the composition of zooplankton species that serve as its foundation. Seven waterbody groups have been distinguished: waterbodies of flood lands, river valley terraces, steppe watersheds, brackish lagoons, brackish lagoons connected to irrigation networks, excavated ponds, and puddles. The specificity of zooplankton species composition in different types of temporary waterbodies is shown. A significant influence of waterbody lifetime on the number of zooplankton species has been revealed, with the waterbody capacity and surface area in the period of maximal water level also being of great importance.     

Modern approaches for the biological control of vertebrate pests: An Australian perspective

Vertebrate pests cost Australia at least $1 billion annually in lost agricultural production and environmental damage. The spectacular success of myxomatosis in the 1950s and more recently, rabbit hemorrhagic disease, in the biological control of European rabbits has led to ongoing research into similar solutions for other vertebrate pests. There are significant barriers to the successful employment of biological control options including the obvious technological ones, such as host-specificity, as well as the investment required, public concerns and regulatory requirements. The role of biological control in vertebrate pest management and the attempts to develop such strategies in Australia is reviewed with emphasis on species specific case studies for rabbits, cane toads and carp, and the generic approaches of immunocontraception and daughterless genes.     

Models for integrated pest control and their biological implications

Successful integrated pest management (IPM) control programmes depend on many factors which include host-parasitoid ratios, starting densities, timings of parasitoid releases, dosages and timings of insecticide applications and levels of host-feeding and parasitism. Mathematical models can help us to clarify and predict the effects of such factors on the stability of host-parasitoid systems, which we illustrate here by extending the classical continuous and discrete host-parasitoid models to include an IPM control programme. The results indicate that one of three control methods can maintain the host level below the economic threshold (ET) in relation to different ET levels, initial densities of host and parasitoid populations and host-parasitoid ratios. The effects of host intrinsic growth rate and parasitoid searching efficiency on host mean outbreak period can be calculated numerically from the models presented. The instantaneous pest killing rate of an insecticide application is also estimated from the models. The results imply that the modelling methods described can help in the design of appropriate control strategies and assist management decision-making. The results also indicate that a high initial density of parasitoids (such as in inundative releases) and high parasitoid inter-generational survival rates will lead to more frequent host outbreaks and, therefore, greater economic damage. The biological implications of this counter intuitive result are discussed.     

Engineering and biological approaches to the restoration from eutrophication of shallow lakes in which aquatic plant communities are important components

Engineering approaches (nutrient removal, sediment pumping, hypolimnion oxygenation, alum treatments) may be most appropriate to deep lakes where the aim of restoration from eutrophication is simply to reduce the production and crop of one component, the phytoplankton. They do not always give the desired results because the nutrient loading may only be reduced to a limited extent. There are additional problems in shallow lakes where change of state between community dominance (aquatic plants versus plankton) is wanted. Each community has powerful buffering mechanisms and biomanipulation may be essential to switch one state to another even with considerable nutrient reduction. For the phytoplankton-dominated community the buffers include the advantages of early growth, lower diffusion pathways for CO₂, overhead shading, and an absence of large cladoceran grazers. This later is because open-water shallow environments provide no refuges against predation for the large Cladocera which are both the most efficient grazers and the most favoured prey for fish. Restoration of aquatic plants may then require provision of refuges for the grazers. Different sorts of refuge are discussed using case studies of Hoveton Great Broad and Cockshoot Broad in the Norfolk Broadland.     

Effects of moderate shade and irrigation with eutrophicated water on the nitrogen economy of Mediterranean oak seedlings

We evaluated the effects of moderate shade (43% vs. 100% of full sunlight) and irrigation with eutrophicated river water (daily vs. alternate-day watering) on growth and nitrogen economy of seedlings of three Mediterranean oak species, two evergreen (Quercus coccifera, Quercus ilex subsp. ballota) and a deciduous (Quercus faginea), grown in pots outdoors. Seedling biomass, N pool, N concentration and N losses by litter fall were measured at the beginning (March 2002) and end (November 2002) of a growing season. All species showed an increase of biomass and N pool under shade and/or high irrigation, while only Q. coccifera – from more arid regions – did the same under full sunlight and low irrigation. At the end of the experiment, biomass of the evergreens was higher in shade than in sun, and in high than in low irrigation, while Q. faginea – from more humid zones – responded to irrigation only. Shade-induced growth was accompanied by a decline in N concentration in the evergreens, but irrigation reduced N concentration only of Q. faginea. Shade, but not irrigation, reduced above-ground N loss. We conclude that both treatments differentially affected the evergreen and the deciduous oaks, probably due to differences in plant hydraulic and stomatal conductance. Although both treatments have similar effects on the growth of evergreens, they produced different effects on seedling N economy, which may have important consequences on future field seedling performance.     

3种拟青霉生物学特性的分析研究

通过分析研究3种拟青霉在PDA培养基上的最佳生长曲线、最大产孢量、最佳生长适温和最佳生长pH值等生物学特性,发现3种拟青霉均可在中、低温环境下生长,且在较短时间内成熟产孢。这为春秋两季林间的害虫生物防治奠定了侵染基础,同时分析研究3种拟青霉不同的生境条件,也为林间混菌持续控制害虫和菌种发酵生产提供了参考指导。     

三叶草斑潜蝇的寄生蜂及其应用

本文就三叶草斑潜蝇Liriomyza trifolii(Burgess)的寄生蜂种类、生物学特性、寄主选择性和农药对寄生蜂的影响及寄生蜂在生物防治中的应用等方面的研究进展进行了综述。     

Effects of backbone structures and stereospecificities of lipid A-subunit analogues on their biological activities

Among chemically synthesized analogues corresponding to the nonreducing sugar part of lipid A, we have found an analogue (GLA-27) which exhibits Limulus, mitogenic, polyclonal B cell activation (PBA), interferon-inducing, and tumor necrosis factor (TNF)-inducing activities but not pyrogenic activity. The structure of GLA-27 comprises 4-O-phosphono-D-glucosamine with tetradecanoyl and 3-tetradecanoyloxytetradecanoyl (C14-O-(C14] groups as the 3-O- and 2-N-acyl substituents, respectively. Derivatives of GLA-27 with different backbone structures, such as the 1-deoxy, 3-epimeric, 3-amino, and 1-deoxy-3-epimeric derivatives of glucosamine, were chemically synthesized, and their mediator-inducing activities such as interferon- and TNF-inducing activities were investigated in comparison with their B cell activation activities including mitogenic and PBA activities. Among these derivatives, a derivative with a 1-deoxyglucosamine backbone (GLA-40) exhibited stronger B cell activation activities than those of GLA-27 while the mediator-inducing activities of GLA-40 were weaker than those of GLA-27. In addition to these derivatives, stereoisomers of GLA-27 which possess the (R) and (S) forms of C14-O-(C14) as the 2-N-acyl substituent were also synthesized and their biological activities compared. The (S) isomer exhibited much stronger mediator-inducing activities than the (R) isomer. On the other hand, B cell activation activities of the (R) isomer were strong and those of the (S) isomer weak. These results clearly demonstrate that mediator-inducing activities and B cell activation activities can be selectively expressed by modifying the structures of lipid A analogues.     

Vitrification of large tissues with dielectric warming: biological problems and some approaches to their solution

If large pieces of tissue and organs are to be successfully stored at low temperatures, some means must be found to minimize the disruption of extracellular structures by the ice that develops during conventional cryopreservation methods. The use of sufficiently high concentrations of cryoprotectant (CPA) to vitrify rather than freeze the tissue is a possible solution to this problem, and the retention of function of embryos and elastic arteries after vitrification suggests that some cells and tissues at least can withstand exposure to the high concentrations of CPA necessary for this process to occur. There are, however, additional problems in applying vitrifying techniques to bulky tissues and organs. These are related to the additional time required for tissue equilibration of CPA to occur and the consequences for toxic injury, the difficulty in achieving sufficiently rapid and uniform cooling rates to produce the required glassy state, and the even more rapid and uniform warming rates that are necessary to avoid devitrification. Non-uniformity of temperature will increase the risk of mechanical stresses and fractures developing in the glass during rapid warming. This paper reviews possible strategies and the progress that has been made in overcoming these problems. This will include the permeation of CPA mixtures into whole tissues and possibilities for reducing their toxicity by the inclusion of adjuncts such as ice inhibitors and sugars. The warming of tissues by dielectric heating is currently the only practical means by which sufficiently rapid rates can be achieved in bulky tissues given that the tolerable limits of CPA concentration will most likely be insufficient to prevent the development of ice nuclei during cooling. The biological effects of microwaves are reviewed and their effectiveness in producing the required uniformity in warming of tissue models of various shapes are discussed.     

Behavioral studies,molecular approaches,and modeling: Methodological contributions to biological control success

Modern biological control practitioners must increasingly demonstrate a level of rigor that can only be achieved through use of effective methodological tools such as modeling, behavioral studies and molecular approaches. The use of these technologies is maturing rapidly in biological control and makes tangible contributions to its success. Behavioral studies often uncover important aspects of biology that would otherwise be overlooked, such as the influence of pre-release handling on establishment success and the response of natural enemies to host-induced plant volatiles. Molecular approaches allow the identification and detection of genetically distinct populations of invasive pest species and their natural enemies, tracing the origin of invasive pest populations and compatible natural enemies, and development of improved recombinant natural enemies. Modeling enables theory and empirical observation to optimize agent selection and release, and to predict quantitative impacts on target and non-target populations. All three methodologies, particularly in combination, contribute to our understanding of the reasons for success and failure in biological control, and together with post-release validation studies build the foundations to improve the success of future biological control releases.     

Investigation of native isolates of entomopathogenic fungi for the biological control of three citrus pests

The pathogenicity of 15 isolates of Beauveria bassiana (Balsamo) Vuillemin, five isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and one isolate of M. flavoviride (Gams and Rozsypal) were tested under laboratory conditions against the subterranean life stages of the citrus pests, Ceratitis rosa Karsch, C. capitata Wiedemann (Diptera: Tephritidae) and Thaumatotibia leucotreta Meyrick. (Lepidoptera: Tortricidae). When these citrus pests were treated with a concentration of 1×10⁷ conidia mL^?1, fungal isolates had a significantly greater effect on the adults of C. rosa and C. capitata than they did on the puparia of these two fruit fly species. Further, C. rosa and C. capitata did not differ significantly in their response to entomopathogenic fungi when adult and pupal mycosis were considered. Depending on fungal isolate, the percentage of T. leucotreta adults which emerged from fungal treated sand ranged from 5 to 60% and the percentage of pupae with visible signs of mycosis ranged from 21 to 93%. The relative virulence of the four most promising fungal isolates, as well as the commercially available B. bassiana product, BroadBand® (Biological Control Products, South Africa), were compared against one another as log-probit regressions of mortality against T. leucotreta which exhibited a dose-dependent response. The estimated LC₅₀ values of the three most virulent B. bassiana isolates ranged from 6.8×10⁵ to 2.1×10⁶ conidia mL^?1, while those of the least pathogenic ranged from 1.6×10⁷ to 3.7×10⁷ conidia mL^?1.     

Effects of caffeine, ephedrine and their combination on time to exhaustion during high-intensity exercise

This study investigated the effects of acute ingestion of caffeine (C), ephedrine (E) and their combination (C+E) on time to exhaustion during high-intensity exercise. Using a repeated-measures, double-blind design, eight male subjects exercised on a cycle ergometer at a power output that led to exhaustion after about 12.6 min during a placebo (P) control trial. They did this 1.5 h after ingesting either C (5 mg · kg⁻¹), E (1 mg · kg⁻¹), C+E, or P. Trials were separated by 1 week. Venous blood was sampled before and during exercise. The mean (SD) times to exhaustion were 12.6 (3.1) (P), 14.4 (4.1) (C), 15.0 (5.7) (E) and 17.5 (5.8) (C+E) min. Only the C+E treatment significantly increased time to exhaustion compared to P. Oxygen consumption (V˙O₂), carbon dioxide production (V˙CO₂), minute ventilation (V˙ _E) and the respiratory exchange ratio (RER) were similar during exercise for all trials. Heart rate during exercise was significantly increased for the C+E and C trials compared to P. Subjective ratings of perceived exertion during exercise were significantly lower after C+E compared to P. All treatments significantly increased lactate levels. Free fatty acid (FFA) levels were significantly increased by C ingestion. Glycerol levels were increased by C+E and C ingestion. Glucose levels were also higher with the drug treatments compared to P. Increased monamine availability after C+E treatment was suggested by measurements of catecholamines and dopamine. In conclusion, the combination of C+E significantly prolonged exercise time to exhaustion compared to P, while neither C nor E treatments alone significantly changed time to exhaustion. The improved performance was attributed to increased central nervous system stimulation. Accepted: 23 September 1997     

A model of glucose kinetics and their control by insulin,compartmental and noncompartmental approaches

Compartmental and noncompartmental models are used to quantify, from multiple steady-state tracer experiments, glucose kinetics and the effect of insulin upon them. Some aspects of experiment design are discussed. A physiological three-compartment model of glucose kinetics is proposed which provides a new quantitative picture of insulin control of glucose metabolism. Noncompartmental modeling is shown to have structural errors which prevent physiological insight. Compartmental models make a better use of the informational content of kinetic data, even if more demanding both in terms of modeling and computational effort and in terms of physiological thinking.