Cost of cooperation rules selection for cheats in bacterial metapopulations

Bacteria secrete a large variety of beneficial metabolites into the environment, which can be shared as public goods among producing bacteria, but also be exploited by nonproducing cheats. Here, we focus on cooperative production of iron-chelating molecules (siderophores) in the bacterium Pseudomonas aeruginosa to study how relevant ecological factors influence selection for cheating. We designed patch-structured metapopulations that allowed us introducing among-patch ecological variation. We found that cheating readily evolved in uniform iron-limited environments. This finding is explained by severe iron limitation demanding high siderophore-production efforts, which results in high metabolic costs accruing to cooperators, and thereby facilitates the spread of cheats. In contrast, we observed a significant reduction or even negation of selection for cheating in metapopulations where we introduced patches with increased iron availability and/or opportunities to recycle siderophores. These findings are compatible with the view that cheats are less likely to invade in environments that allow bacteria to reduce siderophore-production efforts, as this lowers the overall metabolic costs accruing to cooperators. Because we increased iron availability and siderophore recycling opportunities moderately, and only in some patches, our findings demonstrate that already-small local variations in ecological conditions as occurring in nature can significantly affect selection for public-goods secretion in microbes. In addition, we found that most (84.6%) of the evolved cheats were partially deficient for siderophore production and not loss-of-function mutants. Genetic considerations indicate that mutations leading to partial deficiency occur more frequent than mutations leading to loss of function, but also suggest that partially deficient mutants might often be the more competitive cheats.     

Power to the people: a wiki-governance model for biobanks

Biobanks are adopting various modes of public engagement to close the agency gap between participants and biobank builders. We propose a wiki-governance model for biobanks that harnesses Web 2.0, and which gives citizens the ability to collaborate in biobank governance and policymaking.     

海南省公益林生态系统服务功能及其价值评估研究

构建了海南省公益林生态系统服务功能的评价指标体系,依据2009年国家森林资源清查数据、尖峰岭生态定位站连续观测数据、社会公共数据等数据资料,利用影子工程法、替代工程法等方法,首次对海南全省公益林生态服务功能价值(2010年)进行评估。结果显示,海南省公益林生态系统服务功能2010年总价值为1113.60亿元,相当于当年全省生产总值(GDP)2050亿元的54%,单位面积森林提供的服务功能的价值为14.09万元/hm2。由于考虑森林提供负氧离子的功能,8项森林生态系统服务功能价值贡献值之中,净化大气环境>固碳释氧>生物多样性>水源涵养>森林保护>森林游憩>保育土壤>积累营养物质。     

The type and timing of social information alters offspring production

The acquisition and use of information are essential for decision-making in an uncertain world. The use of social information, or information from the behaviour of others, may be a common and efficient mechanism to improve estimates of resource quality by animals. According to theory, social information cues with higher information content should have a greater influence on decision-making, and current information should be weighed more than prior information. However, experimental tests of these hypotheses remain scarce. We exposed female cactus bugs (Chelinidea vittiger) to different types of social information (the presence of conspecific eggs or nymphs) presented at different times (current or prior to egg laying) to determine the influence of social information on offspring production. We found that social information substantially altered the number of eggs produced. The presence of conspecific eggs, regardless of timing, consistently increased egg production, whereas nymphs only increased egg production when present during egg laying. We conclude that the type and timing of social information may have an important, yet unappreciated, influence on reproductive allocation.     

Parasitism of non-target lepidoptera by mass released Trichogramma brassicae and its implication for the larval parasitoid Lydella thompsoni

The release of high numbers of the eggparasitoid Trichogramma brassicae Bezd.(Hym. Trichogrammatidae) to control theEuropean corn borer (ECB), Ostrinianubilalis Hb. (Lep.: Crambidae) in maize hasraised concerns about potential negativeeffects on native natural enemies. The nativelarval parasitoid Lydella thompsoniHerting (Dipt.: Tachinidae) is the mostfrequent and important ECB parasitoid insouthern Switzerland and can achieve highparasitism rates. Its first generation emergestoo early to find ECB larvae and must rely onalternative hosts living in natural habitatsclose to maize fields. Inundative releases ofT. brassicae coincide with theoviposition period of the alternative hosts ofthe tachinid. T. brassicae moving out ofrelease fields may attack and diminish thepopulation of these hosts, creating abottleneck situation for L. thompsoni inthe subsequent spring. Laboratory hostspecificity tests showed that the tachinid'stwo most abundant spring hosts Archanarageminipuncta Haworth (1809) (Lep.: Noctuidae)and Chilo phragmitellus Hübner (1805)(Lep.: Crambidae) are successfully parasitisedby T. brassicae females in no-choicesituations. Our extensive field surveys,however, showed that the two tested springhosts escape parasitism since their eggs arewell hidden or not attractive. Negativeeffects of inundative releases of T.brassicae on the native tachinid fly L. thompsoni, such as population densityreduction, displacement, or local extinction,are very unlikely.     

Theoretical Study of Antagonists and Inhibitors of Mammalian Adenosine Deaminase: II. Isomeric Aza-deazaanalogues of Adenosine

Isomeric aza-deazaanalogues of adenosine and their N1-protonated forms (except for that of 8-aza-1-deazaadenosine) were studied by computer modeling to find a relationship between their molecular structures and the properties as substrates for the mammalian adenosine deaminase. The atomic charge distribution and maps of electrostatic potential around their van der Waals molecular surface were calculated using the ab initioSTO-3G method. The conformational studies were carried out by the MM⁺ method of molecular mechanics. The previously proposed mechanism of the substrate acceptance in the active site of mammalian adenosine deaminase was refined, and the potential substrate properties were predicted for two previously unstudied adenosine analogues, 5-aza-9-deazaadenosine and 8-aza-3-deazaadenosine.     

Field evaluation of alpha-chlorohydrin against the Indian mole rat: studies on toxic and antifertility effects

Field acceptance and efficacy of a toxicant-sterilant, alpha-chlorohydrin (α-CH), at its 0.5% concentration in bait were evaluated against rodents in sugarcane fields which harboured high populations of the Indian mole rat Bandicota bengalensis (Trap Index (TI) = 53.6 rats/100 traps/24 h) followed by that of the Indian bush rat Golunda ellioti (TI = 28.6) and soft-furred field rat Rattus meltada (TI = 1.8). Acceptance of the α-CH bait by rodents in the fields was evident from complete consumption of the offered bait at most of the baiting points. The treatment (72 h exposure to the poison bait) resulted in 63.7% to 82.9% rodent mortality. Survey of the mature sugarcane crop revealed that the percentage of rodent cut canes in the treated fields (7.6% to 16.2%) was significantly less than that of the reference fields (26.3%). Most of the surviving male B. bengalensis, captured after 15 days of the treatment, had developed sterility as revealed by the functional abnormalities in their testes and epid-idymides. They showed decreased thickness of the seminiferous tubules, lower population of spermatogenic cells, cauda epididymal sperm concentration, live sperm and sperm mortality. A nonsignificant positive correlation between the testicular weight and sperm motility in males from treated fields indicated the effect of α-CH at maturation level in the cauda epididymides. Overall, it was evident that a significant proportion of the surviving B. bengalensis had become permanently sterile as a consequence to the development of spermatocoeles in the caput epididymides and the remaining had significantly low numbers (< 30%) of motile sperm in their cauda epididymides which was, obviously, a handicap for successful fertilisation.     

Genomics,ICT and the formation of R&D networks

Research in genomics is an example of changes induced by information and communication technologies (ICT). The emergence of interconnected ICT support for scientific work and the handling of information have changed the challenges in genomics as well as other scientific fields. The promises are significant but a large degree of uncertainty remains. While the information space is opened up, R&D cooperation essential to reaping the benefits for companies is still difficult. Moreover, in order to benefit in full from the possibility to combine knowledge on a larger scale, knowledge repositories and places of knowledge creation need to be combined. This paper discusses the new strategies of information networking between companies that emerges in response to this challenge. It concludes with an outline of a research agenda for genomics and society.     

Dietary modulation of oxidative stress in chronic obstructive pulmonary disease patients

Abstract

A total of 267 clinically stable chronic obstructive pulmonary disease (COPD) patients provided complete data about diet and oxidative stress markers in order to assess the relationship between antioxidant rich food groups and nutrients, and serum markers of oxidative stress in COPD. Dietary data of the last 2 years was assessed using a validated food frequency questionnaire (122 items). Levels of carbonyls, nitrotyrosine, malondialdehyde and reduced glutathione (GSH) were measured in serum. Vitamin E intake was inversely associated with levels of carbonyls (p = 0.05) and olive oil was positively associated with GSH levels (p = 0.01), in active smokers. Intake of vegetables was related to a decrease of malondialdehyde levels (p = 0.04) in former smokers. No statistically significant associations were found between remaining dietary antioxidants and serum oxidative stress markers. These results provide new data for a potential dietary modulation of systemic oxidative stress in COPD patients, particularly in those that continue smoking.