Organochlorine compounds in red deer (Cervus elaphus L.) and fallow deer (Dama dama L.) from inland and coastal Croatia

Polychlorinated biphenyl (PCB) and organochlorine pesticide (OCP) levels in fat tissue of red and fallow deer (Cervus elaphus L. and Dama dama L.) from two inland and an Adriatic area were established. Of 17 analysed PCBs, PCB-28, PCB-138, PCB-153, PCB-180 and PCB-118 were found in all samples, whilst PCB-101 and PCB-170 were found in more than 50% of samples. They ranged between 0.03 and 5.98 ng g(-1) fat weight. Of seven analysed OCPs, HCB, γ-HCH and 1,1-dichloro-2,2-di(4-chlorophenyl)ethylene (DDE) were found in all samples, whilst β-HCH was found in more than 50% of samples. They ranged between 0.17 and 22.14 ng g(-1) fat weight. The dominating compounds were DDE, PCB-138, PCB153, PCB-118 and PCB-180. According to the Duncan multistage test, the levels of PCB-138, PCB-153, PCB 170 and PCB-180 were significantly higher in perirenal fat samples of specimens taken from the Adriatic area. DDE was significantly higher in the inland deer samples. Some species differences were determined and were mostly related to higher PCB and β-HCH levels in fallow deer samples and higher DDE levels in red deer samples. No sex difference was established. As for age, significantly higher levels of PCB-118 and PCB-52 were found in fawns.     

Analysis of brood sex ratios: implications of offspring clustering

Generalized linear models (GLMs) are increasingly used in modern statistical analyses of sex ratio variation because they are able to determine variable design effects on binary response data. However, in applying GLMs, authors frequently neglect the hierarchical structure of sex ratio data, thereby increasing the likelihood of committing 'type I' error. Here, we argue that whenever clustered (e.g., brood) sex ratios represent the desired level of statistical inference, the clustered data structure ought to be taken into account to avoid invalid conclusions. Neglecting the between-cluster variation and the finite number of clusters in determining test statistics, as implied by using likelihood ratio-based L²-statistics in conventional GLM, results in biased (usually overestimated) test statistics and pseudoreplication of the sample. Random variation in the sex ratio between clusters (broods) can often be accommodated by scaling residual binomial (error) variance for overdispersion, and using F-tests instead of L²-tests. More complex situations, however, require the use of generalized linear mixed models (GLMMs). By introducing higher-level random effects in addition to the residual error term, GLMMs allow an estimation of fixed effect and interaction parameters while accounting for random effects at different levels of the data. GLMMs are first required in sex ratio analyses whenever there are covariates at the offspring level of the data, but inferences are to be drawn at the brood level. Second, when interactions of effects at different levels of the data are to be estimated, random fluctuation of parameters can be taken into account only in GLMMs. Data structures requiring the use of GLMMs to avoid erroneous inferences are often encountered in ecological sex ratio studies.     

Toxicity of metalaxyl,azoxystrobin, dimethomorph,cymoxanil, zoxamide and mancozeb to Phytophthora infestans isolates from Serbia

A study of the in vitro sensitivity of 12 isolates of Phytophthora infestans to metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb, was conducted. The isolates derived from infected potato leaves collected at eight different localities in Serbia during 2005–2007. The widest range of EC₅₀ values for mycelial growth of the isolates was recorded for metalaxyl. They varied from 0.3 to 3.9 μg mL^?1 and were higher than those expected in a susceptible population of P. infestans. The EC₅₀ values of the isolates were 0.16–0.30 μg mL^?1 for dimethomorph, 0.27–0.57 μg mL^?1 for cymoxanil, 0.0026–0.0049 μg mL^?1 for zoxamide and 2.9–5.0 μg mL^?1 for mancozeb. The results indicated that according to effective concentration (EC₅₀) the 12 isolates of P. infestans were sensitive to azoxystrobin (0.019–0.074 μg mL^?1), and intermediate resistant to metalaxyl, dimethomorph and cymoxanil. According to resistance factor, all P. infestans isolates were sensitive to dimethomorph, cymoxanil, mancozeb and zoxamide, 58.3% of isolates were sensitive to azoxystrobin and 50% to metalaxyl. Gout's scale indicated that 41.7% isolates were moderately sensitive to azoxystrobin and 50% to metalaxyl.     

Toxicity of fungicides with different modes of action to Cladobotryum dendroides and Agaricus bisporus

Isolates of Cladobotryum dendroides from Serbian mushroom farms and Agaricus bisporus F56 were tested for sensitivity to selected fungicides in vitro. Chlorothalonil was the most toxic fungicide to C. dendroides isolates (EC₅₀ values were below 1.68 mg L^{? 1}). Trifloxystrobin and kresoxim-methyl were not effective in growth inhibition of C. dendroides isolates (EC₅₀ values exceeded 300 mg L^{? 1}). Metalaxyl-M+mancozeb was the most toxic fungicide to strain F56 of A. bisporus, and iprodione the least toxic. The fungicide selectivity indexes for both C. dendroides and A. bisporus indicated that iprodione, chlorothalonil, captan and metalaxyl-M+mancozeb had satisfactory selective fungitoxicity. Iprodione had the best selectivity to both the pathogen and the host, although inferior than prochloraz manganese and carbendazim, fungicides officially recommended for mushroom cultivation in European Union (EU) countries.     

Internal ecosystem feedbacks enhance nitrogen-fixing cyanobacteria blooms and complicate management in the Baltic Sea

Eutrophication of the Baltic Sea has potentially increased the frequency and magnitude of cyanobacteria blooms. Eutrophication leads to increased sedimentation of organic material, increasing the extent of anoxic bottoms and subsequently increasing the internal phosphorus loading. In addition, the hypoxic water volume displays a negative relationship with the total dissolved inorganic nitrogen pool, suggesting greater overall nitrogen removal with increased hypoxia. Enhanced internal loading of phosphorus and the removal of dissolved inorganic nitrogen leads to lower nitrogen to phosphorus ratios, which are one of the main factors promoting nitrogenfixing cyanobacteria blooms. Because cyanobacteria blooms in the open waters of the Baltic Sea seem to be strongly regulated by internal processes, the effects of external nutrient reductions are scale-dependent. During longer time scales, reductions in external phosphorus load may reduce cyanobacteria blooms; however, on shorter time scales the internal phosphorus loading can counteract external phosphorus reductions. The coupled processes inducing internal loading, nitrogen removal, and the prevalence of nitrogen-fixing cyanobacteria can qualitatively be described as a potentially self-sustaining "vicious circle." To effectively reduce cyanobacteria blooms and overall signs of eutrophication, reductions in both nitrogen and phosphorus external loads appear essential.     

Toxicity of twenty-two plant essential oils against pathogenic bacteria of vegetables and mushrooms

Toxicity of twenty-two essential oils to three bacterial pathogens in different horticultural systems: Xanthomonas campestris pv. phaseoli (causing blight of bean), Clavibacter michiganensis subsp. michiganensis (bacterial wilt and canker of tomato), and Pseudomonas tolaasii (causal agent of bacterial brown blotch on cultivated mushrooms) was tested. Control of bacterial diseases is very difficult due to antibiotic resistance and ineffectiveness of chemical products, to that essential oils offer a promising alternative. Minimal inhibitory and bactericidal concentrations are determined by applying a single drop of oil onto the inner side of each plate cover in macrodilution assays. Among all tested substances, the strongest and broadest activity was shown by the oils of wintergreen (Gaultheria procumbens), oregano (Origanum vulgare), and lemongrass (Cymbopogon flexuosus. Carvacrol (64.0–75.8%) was the dominant component of oregano oils, while geranial (40.7%) and neral (26.7%) were the major constituents of lemongrass oil. Xanthomonas campestris pv. phaseoli was the most sensitive to plant essential oils, being susceptible to 19 oils, while 11 oils were bactericidal to the pathogen. Sixteen oils inhibited the growth of Clavibacter michiganensis subsp. michiganensis and seven oils showed bactericidal effects to the pathogen. The least sensitive species was Pseudomonas tolaasii as five oils inhibited bacterial growth and two oils were bactericidal. Wintergreen, oregano, and lemongrass oils should be formulated as potential biochemical bactericides against different horticultural pathogens.     

蛀木生物钻刺团水虱是否改变红茄冬红树林的分布形状?

为了评价东非不同空间尺度(1m尺度～l00km尺度)红树林分布区等足类甲壳动物蛀木虫钻刺团水虱(团水虱属)在美国红树红茄冬气生根中出现的情况,进行了野外调查研究.