Xanthomonas campestris pv. campestris race 1 is the main causal agent of black rot of Brassicas in Southern Mozambique

Severe outbreaks of bacterial black rot caused by Xanthomonas campestris pv. campestris (Xcc) were observed in Brassica production fields of Southern Mozambique. The causal agent of the disease in the Mahotas and Chòkwé districts was identified and characterised. In total, 83 Xanthomonas-like strains were isolated from seed samples and leaves of cabbage and tronchuda cole with typical symptoms of the disease. Forty-six out of the 83 strains were found to be putative Xcc in at least one of the tests used: Classical biochemical assays, enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies, Biolog identification system, polymerase chain reaction (PCR) with specific primers and pathogenicity tests. The ELISA tests were positive for 43 strains. Biolog identified 43 strains as Xanthomonas, but only 32 as Xcc. PCR tests with primers targeting a fragment of the hrpF gene were positive for all 46 strains tested. Three strains were not pathogenic or weakly pathogenic and all other strains caused typical black rot symptoms in brassicas. Race type differentiation tests revealed the Xcc strains from Mozambique as members of race 1. The prevalence of this pathogenic race of the Xcc pathogen in Mozambique should be considered when black rot resistant cultivars are evaluated or introduced into the production regions of this country

Regime, the State and Society: Analyzing the Implementation of International Environmental Commitments

In this paper, the relationship between international regimes, states, and societies is examined. The interactions between these levels moderate the influence of international agreements and rules on behavior: they help determine when international agreements are effective. The paper offers one major context for studying the domestic implementation of international agreements, and for developing theories that explain how international agreements influence down to the local level. The authors review and develop numerous hypotheses about the factors that explain successful domestic implementation, and the balance of the roles of the state and non-state actors (e.g. NGOs). The main perspective they propose is one that concentrates on "access" to and "participation" in the policy-making and implementation process as a fruitful way to unravel the main factors that explain effectiveness, as well as the major policy tools available to improve effectiveness of international environmental agreements. The authors also review literature in important fields: domestic public policy implementation, international regimes, and the concept of "compliance"

Influence of dietary fat on the fatty acid pattern of muscle and liver lipids in rainbow trout (Sabno gairdneri)

Groups of one year old rainbow trout (Salmo gairdneri) were fed diets supplemented with 13% of rape seed oil, olive oil, linseed oil or sunflower seed oil. The fishes were kept in fresh water of a temperature about 10°C throughout the 5 weeks experimental period. Random samples of fish were taken at 0, 1, 3 and 5 weeks, boneless filets taken from the back and livers were collected for analysis. The composition of the major fatty acids was determined in fats extracted from the diets and the samples of organs. The results showed the effect of the dietary fatty acids on the deposition in liver and filets. In all groups the major fatty acid of the supplemented fat increased in filets and livers already after one week. The increases continued during the feeding period for fat from the filets, whereas the livers showed the most pronounced increases after one week, followed by moderate increases or even a decrease after 3 and 5 weeks on the diets. There was a corresponding decrease in the percentage values for all other fatty acids except those which are synthesized from the dietary acids or from the metabolic pool. Linoleic and linolenic acids, which are polar (mobile) acids, increased more rapidly and to higher percentage values than the less polar monoene acids of chain length 20 and 22

Estimation of Density-Dependent Mortality of Juvenile Bivalves in the Wadden Sea

We investigated density-dependent mortality within the early months of life of the bivalves Macoma balthica (Baltic tellin) and Cerastoderma edule (common cockle) in the Wadden Sea. Mortality is thought to be density-dependent in juvenile bivalves, because there is no proportional relationship between the size of the reproductive adult stocks and the numbers of recruits for both species. It is not known however, when exactly density dependence in the pre-recruitment phase occurs and how prevalent it is. The magnitude of recruitment determines year class strength in bivalves. Thus, understanding pre-recruit mortality will improve the understanding of population dynamics. We analyzed count data from three years of temporal sampling during the first months after bivalve settlement at ten transects in the Sylt-Rømø-Bay in the northern German Wadden Sea. Analyses of density dependence are sensitive to bias through measurement error. Measurement error was estimated by bootstrapping, and residual deviances were adjusted by adding process error. With simulations the effect of these two types of error on the estimate of the density-dependent mortality coefficient was investigated. In three out of eight time intervals density dependence was detected for M. balthica, and in zero out of six time intervals for C. edule. Biological or environmental stochastic processes dominated over density dependence at the investigated scale

Differential Uptake of Gold Nanoparticles by 2 Species of Tadpole, the Wood Frog (Lithobates Sylvaticus) and the Bullfrog (Lithobates Catesbeianus)

Engineered nanoparticles are aquatic contaminants of emerging concern that exert ecotoxicological effects on a wide variety of organisms. We exposed cetyltrimethylammonium bromide–capped spherical gold nanoparticles to wood frog and bullfrog tadpoles with conspecifics and in combination with the other species continuously for 21 d, then measured uptake and localization of gold. Wood frog tadpoles alone and in combination with bullfrog tadpoles took up significantly more gold than bullfrogs. Bullfrog tadpoles in combination with wood frogs took up significantly more gold than controls. The rank order of weight-normalized gold uptake was wood frogs in combination \u3e wood frogs alone \u3e bullfrogs in combination \u3e bullfrogs alone \u3e controls. In all gold-exposed groups of tadpoles, gold was concentrated in the anterior region compared with the posterior region of the body. The concentration of gold nanoparticles in the anterior region of wood frogs both alone and in combination with bullfrogs was significantly higher than the corresponding posterior regions. We also measured depuration time of gold in wood frogs. After 21 d in a solution of gold nanoparticles, tadpoles lost \u3e83% of internalized gold when placed in gold-free water for 5 d. After 10 d in gold-free water, tadpoles lost 94% of their gold. After 15 d, gold concentrations were below the level of detection. Our finding of differential uptake between closely related species living in similar habitats with overlapping geographical distributions argues against generalizing toxicological effects of nanoparticles for a large group of organisms based on measurements in only one species

Inequality, material well-being, and subjective well-being: Exploring associations for children across 15 diverse countries

Children's material well-being, and the levels of wealth and inequality in societies within which children live, are important factors in determining outcomes. However, less is known about the extent to which these factors have an impact children's subjective well-being, especially in an internationally comparative context. This study draws on data from the Children's Worlds survey, an international study of child subjective well-being, to explore links between national level indicators of wealth and inequality (GDP and Gini coefficients), individual indicators of material well-being (the material resources children report having access to), and subjective well-being. The survey covers 15 diverse countries covering the continents of Europe, Asia, Africa and South America, with samples of at least 3000 per country, ages 8, 10 and 12. Analysis takes the form of a multilevel, varying intercepts and slopes model, examining the association between financial and material resources and inequality and subjective well-being across and between countries. Findings suggest that material resources that children report are significantly associated with subjective well-being, while indicators of financial resources and inequality at the national level are not. While a significant association between material resources and subjective well-being is found across the whole sample, the magnitude of this association, and the association between school- and country-level material resources, varies markedly. Within different countries, the strongest material resources-related predictor of overall subjective well-being may be either at the individual, school or country level