Erythrogenic toxins A, B and C: Occurrence of the genes and exotoxin formation from clinical Streptococcus pyogenes strains associated with streptococcal toxic shock-like syndrome

We report the study of 53 clinical isolates of group A streptococci, all from patients with streptococcal toxic shock-like syndrome. The strains were analysed for the occurrence of the genes of erythrogenic toxins (pyrogenic exotoxins) types A, B and C and in vitro production of these toxins. In contrast to reports indicating that 85% of the toxic shock-like syndrome-associated isolates contained the erythrogenic toxin A gene, only 58.5% of our strains harboured this gene. The erythrogenic toxin C gene was detected in 22.6% of the isolates. Erythrogenic toxin A and erythrogenic toxin B were produced by 68.7% and 58.3% of the strains containing either gene. For all group A streptococci, irrespective of clinical association, the erythrogenic toxin B gene was detected in all the isolates tested. Thus, it is difficult to define a specific role for erythrogenic toxin B in toxic shock-like syndrome as there was no clear correlation between this disease and the presence of toxin genes. Our results suggest the existence of other pathogenic factor(s) produced by group A streptococci which may stimulate human peripheral T lymphocytes in a manner similar to that of erythrogenic toxins, thus explaining different observations in previous epidemiological genetic studies.     

Ultraviolet radiation, toxic chemicals and amphibian population declines

Abstract. As part of an overall ‘biodiversity crisis’, many amphibian populations are in decline throughout the world. Numerous factors have contributed to these declines, including habitat destruction, pathogens, increasing ultraviolet (UV) radiation, introduced non‐native species and contaminants. In this paper we review the contribution of increasing UV radiation and environmental contamination to the global decline of amphibian populations. Both UV radiation and environmental contaminants can affect amphibians at all life stages. Exposure to UV radiation and to certain contaminants can kill amphibians and induce sublethal affects in embryos, larvae and adults. Moreover, UV radiation and contaminants may interact with one another synergistically. Synergistic interactions of UV radiation with contaminants can enhance the detrimental effects of the contaminant and UV radiation.     

Plant Sources of Chinese Herbal Remedies: Effects on Pratylenchus vulnus and Meloidogyne javanica

More than 500 plant species, used alone or in combination, are documented in Chinese traditional medicine to have activity against helminth and micro-invertebrate pests of humans. We subjected 153 candidate medicines or their plant sources to multilevel screening for effectiveness against plant-parasitic nematodes. For extracts effective in preliminary screens, we determined time-course and concentration-response relationships. Seventy-three of the aqueous extracts of medicines or their plant sources killed either Meloidogyne javanica juveniles or Pratylenchus vulnus (mixed stages), or both, within a 24-hour exposure period. Of 64 remedies reported as antihelminthics, 36 were effective; of 21 classi- fied as purgatives, 13 killed the nematodes; of 29 indicated as generally effective against pests, 13 killed the nematodes. Sources of extracts effective against one or both species of plant-parasitic nematodes are either the whole plant or vegetative, storage or reproductive components of the plants. Effective plants include both annuals and perennials, range from grasses and herbs to woody trees, and represent 46 plant families.     

Ichtyotoxic activity of extracts from Mexican marine macroalgae

Seventy-three species of macroalgae from the Mexican Pacific, Atlantic and Caribbean coast were screened for ichtyotoxic activity. Ethanolic, acetonic and aqueous extracts were prepared and tested against the fish Carassius auratus. The extracts were classified on the basis of their effects as: toxic if the fish died in two hours or less; moderately toxic, if the organism behaved abnormally but death did notoccur, and non-toxic if the fish did not display any change. 79% species were ichtyotoxic to some degree. Extracts of 39 species were toxic, with at least one extract with lethal effects, 19 were moderately toxic and 15 species were non-toxic. Only the extracts ofDictyota bartayresiana, Dictyota cervicornis,Lobophora variegata, Bryothamnion triquetrum and Laurencia obtusa were toxic in all three solvents. The acetone and ethanol extracts were more active, and therefore are more suitable for extraction of toxic substances. This revised version was published online in August 2006 with corrections to the Cover Date.     

Fluoride effects on leaf cell ultrastructure of olive trees growing in the vicinity of the Aluminium Factory of Greece

Summary Leaves of olive trees growing in the vicinity of the Aluminium Factory of Greece were ultrastructurally investigated in order to determine any malformations caused by environmental air pollutants, especially hydrogen fluoride, in comparison with control samples and normal seasonal senescence. Estimation of some elements accumulated by these leaves showed that they contained high amounts of F and Al attributable to the operation of the nearby factory. The most seriously effected cell components were found to be the mesophyll chloroplasts that show a dilation of the intrathylakoid space, increase of the number of plastoglobuli, discoloration of plastoglobuli, accumulation of large starch grains and an overall disorganized appearance of the organelle. The nuclear crystalloid inclusions have unusual shapes, while the vacuoles contain a fibrillar/granular material that increases their electron density. It is concluded that the ultrastructural malformations are caused by a combination of environmental stresses and air pollutants.This paper is dedicated to Professor Dr. Eberhard Schnepf on the occasion of his 60^th birthday.     

Amyloid by Design: Intrinsic Regulation of Microbial Amyloid Assembly

The term amyloid has historically been used to describe fibrillar aggregates formed as the result of protein misfolding and that are associated with a range of diseases broadly termed amyloidoses. The discovery of “functional amyloids” expanded the amyloid umbrella to encompass aggregates structurally similar to disease-associated amyloids but that engage in a variety of biologically useful tasks without incurring toxicity. The mechanisms by which functional amyloid systems ensure nontoxic assembly has provided insights into potential therapeutic strategies for treating amyloidoses. Some of the most-studied functional amyloids are ones produced by bacteria. Curli amyloids are extracellular fibers made by enteric bacteria that function to encase and protect bacterial communities during biofilm formation. Here we review recent studies highlighting microbial functional amyloid assembly systems that are tailored to enable the assembly of non-toxic amyloid aggregates.     

Riochemical and physiological effects in farmed Baltic salmon fed lipids containing xenobiotics extracted from Baltic herring

During a 2-year experimental period female baltic salmon (Salmo salar) were fed pellets impregnated with oil extracted from Baltic herring (Clupea harengus). This extract contained lipid-soluble xenobiotics present in Baltic herring, which constitute a major part of the natural diet of Baltic salmon. The fish were examined at the time of ovulation in November each year. After 2 years of feeding, the load of polychlorinated dibenzo-paradioxins and furans in the exposed group was about twice that in the control group, but still low compared with concentrations in feral Baltic salmon. In spite of the relatively low exposure level, several vital biochemical functions were disturbed in the treated fish. Organic skeletal variables were affected indicating that the bone metabolism had been altered. Furthermore, the activities of enzymes involved in steroid biosynthesis were affected, which could lead to disturbances in reproductive functions. Splenocytes from exposed fish sampled in November 1990 showed a reduced mitogenic response, indicating that their immune system was suppressed. Feeding the salmon with pollutant-impregnated pellets also resulted in an induction of the hepatic ethoxyresorufin-O-deethylase (EROD) activity after only 6 weeks of exposure. Likewise, morphological abnormalities, i.e. hypertrophic hepatocytes and various stages of hepatic degeneration, were already apparent after 6 weeks of exposure. However, no EROD induction or morphological responses were recorded at the second and third sampling event, i.e. after one and 2 years of exposure, respectively. this could indicate that some physiological functions may adapt to a restricted xenobiotic load.     

The first insight into the trace element status of human adrenal gland accompanied by elemental alterations in adrenal adenomas

BackgroundThe baseline status of trace metals in adrenal tissue is unresolved, while the elemental profile for any adrenal pathology has not been examined so far. This study aimed to determine the baseline status of important toxic (Ni, As, Cd, Pb, Th, U) and essential trace elements (Mn, Co, Cu, Zn, Se) in healthy adrenal tissues (HATs) as well as to examine whether there are alterations in the elemental composition of adenomatous adrenal tissues (AATs). Furthermore, this study aimed to find potential trace metals that could play a role in the pathogenesis of adrenal adenoma (AA).MethodsThe study included 45 patients diagnosed with AA. Impacts of relevant parameters such as gender, age, smoking habits and nodular sizes were considered. All samples were subjected to microwave digestion and the trace elements were determined by inductively coupled plasma mass spectrometry (ICP-MS).ResultsThis is the first study that provided an insight into the elemental status of HATs. It was also shown that AATs had altered trace metal contents. Compared to HATs, the most significant findings were related to the high content of essential (Cu, Mn, Se, Zn) and Pb as a non-essential metal. Although gender, age and smoking habits had a modest effect on metal profiles, the most significant alterations were related to the nodular diameter above 4 cm, indicating that the growth of benign tumor could influence changes in elemental composition.ConclusionFor the first time the baseline contents of essential and toxic trace metals in HATs were determined. The results of this study may highlight the role of toxic and essential trace metals in AAs and could provide new insights into the molecular basis of pathophysiological changes caused by the hazardous effects of trace metals on adrenal structure and function.     

The combined effect of persistent organic pollutants in the serum POP mixture in Greenlandic Inuit: xenoestrogenic,xenoandrogenic and dioxin-like transactivities

Greenlandic Inuit have high body burden of persistent organic pollutants (POPs). We analyzed the combined effect of the actual lipophilic serum POP mixture on estrogen-, androgen- and aryl hydrocarbon-receptor functions as effect biomarkers, and the associations between the effect biomarkers and serum POPs, and lifestyle characteristics. The serum POPs were extracted from 232 Inuit from Ittoqqortoormiit, Narsaq and Qeqertarsuaq. The POP-related receptor transactivities correlated negatively to the POP levels and were associated to the lifestyle characteristics. The POP-related receptor transactivities can be used as effect biomarkers. The serum POPs have hormone disruptive potentials.     

Rendiconti Delle Sedute E Brevi Comunicazioni

Abstract

The development of effective strategies to rehabilitate compromised environments is one of the major challenges facing the postindustrial society, since most of the habitats are becoming progressively polluted due to indiscriminate discharge of contaminants generated by anthropogenic activities. Several aquatic photosynthetic organisms can be used to treat wastewaters in primary and tertiary treatments, including cyanobacteria, algae and higher plants. In this review, we summarize the results obtained in the remediation of polluted waters by photosynthetic organisms and discuss the future perspective of phytoremediation.