EFFECT OF THE SUPPORT ON THE IMMOBILIZATION OF PSEUDOMONAS DENITRIFICANS CELLS

Abstract Biological means for biodegradation of pollutants in wastewater hav

Reappraisal of Vipera aspis Venom Neurotoxicity

BACKGROUND: The variation of venom composition with geography is an important aspect of intraspecific variability in the Vipera genus, although causes of this variability remain unclear. The diversity of snake venom is important both for our understanding of venomous snake evolution and for the preparation of relevant antivenoms to treat envenomations. A geographic intraspecific variation in snake venom composition was recently reported for Vipera aspis aspis venom in France. Since 1992, cases of human envenomation after Vipera aspis aspis bites in south-east France involving unexpected neurological signs were regularly reported. The presence of genes encoding PLA(2) neurotoxins in the Vaa snake genome led us to investigate any neurological symptom associated with snake bites in other regions of France and in neighboring countries. In parallel, we used several approaches to characterize the venom PLA(2) composition of the snakes captured in the same areas. [br/] METHODOLOGY/PRINCIPAL FINDINGS: We conducted an epidemiological survey of snake bites in various regions of France. In parallel, we carried out the analysis of the genes and the transcripts encoding venom PLA(2)s. We used SELDI technology to study the diversity of PLA(2) in various venom samples. Neurological signs (mainly cranial nerve disturbances) were reported after snake bites in three regions of France: Languedoc-Roussillon, Midi-Pyrénées and Provence-Alpes-Côte d'Azur. Genomes of Vipera aspis snakes from south-east France were shown to contain ammodytoxin isoforms never described in the genome of Vipera aspis from other French regions. Surprisingly, transcripts encoding venom neurotoxic PLA(2)s were found in snakes of Massif Central region. Accordingly, SELDI analysis of PLA(2) venom composition confirmed the existence of population of neurotoxic Vipera aspis snakes in the west part of the Massif Central mountains. [br/] CONCLUSIONS/SIGNIFICANCE: The association of epidemiological studies to genetic, biochemical and immunochemical analyses of snake venoms allowed a good evaluation of the potential neurotoxicity of snake bites. A correlation was found between the expression of neurological symptoms in humans and the intensity of the cross-reaction of venoms with anti-ammodytoxin antibodies, which is correlated with the level of neurotoxin (vaspin and/or ammodytoxin) expression in the venom. The origin of the two recently identified neurotoxic snake populations is discussed according to venom PLA(2) genome and transcriptome data

Parasites of non-native freshwater fishes introduced into england and wales suggest enemy release and parasite acquisition

When non-native species are introduced into a new range, their parasites can also be introduced, with these potentially spilling-over into native hosts. However, in general, evidence suggests that a high proportion of their native parasites are lost during introduction and infections by some new parasites from the native range might occur, potentially resulting in parasite spill-back to native species. These processes were investigated here using parasite surveys and literature review on seven non-native freshwater fishes introduced into England and Wales. Comparison of the mean numbers of parasite species and genera per population for each fish species England andWaleswith their native ranges revealed\9 % of the native parasite fauna were present in their populations in England and Wales. There was no evidence suggesting these introduced parasites had spilled over into sympatric native fishes. The non-native fishes did acquire parasites following their introduction, providing potential for parasite spill-back to sympatric fishes, and resulted in non-significant differences in overall mean numbers of parasites per populations between the two ranges. Through this acquisition, the non-native fishes also had mean numbers of parasite species and genera per population that were not significantly different to sympatric native fishes. Thus, the non-native fishes in England and Wales showed evidence of enemy release, acquired new parasites following introduction providing potential for spill-back, but showed no evidence of parasite spill-over

The Effect of Co-activation of Antagonist Muscles on Motor Cortex Excitability: A Transcranial Magnetic Stimulation Study

The effect of unilateral tonic muscle activity with and without co-activation of the antagonists on motor cortex excitability has been studied in seven right handed healthy volunteers. Contralateral motor evoked potentials (MEPs) were recorded from the first dorsal interosseous muscles of right hands in response to transcranial magnetic stimulation (TMS) during relax, isometric index finger abduction and antagonistic co-activation. The intracortical facilitation (ICF), short- and long-latency intracortical inhibition (SICI and LICI) were investigated by paired-pulse TMS. The unilateral tonic activation of the right hand facilitated MEPs in response to single-pulse TMS. The increase of MEP amplitudes was significantly greater during isometric index finger abduction compared to co-activation of antagonist muscles. During paired-pulse TMS with short interstimulus intervals, the SICI (interstimulus interval of 3 ms) was not influenced by the unilateral tonic activity while ICF (interstimulus interval of 13 ms) was suppressed. During paired-pulse TMS with longer interstimulus interval (100 ms) the LICI was not influenced during isometric index finger abduction while during antagonistic co-activation the LICI was significantly less pronounced. The decreased LICI is assumed to reflect mechanisms underlying the co-activation of antagonists

IMPACT OF NITRATE IONS CONCENTRATION ON THE DENITRIFICATION PROCESS

Underground and surface water are contaminated by nitrate in several ways. Nitrate originated from agriculture is increasingly growing all over the world due to the extreme use of fertilizers. Nitrate salts reach the groundwater as they percolate through the soil. Some other sources of nitrate in ground and surface water are from uncontrolled discharges of treated or un-treated wastewater from domestic and industrial sources, landfills and animal waste particularly from animal farms. Various methods for treatment of water from nitrates are known, but the majority of them generate secondary pollutants. An exception is the biological denitrification, at which nitrates are reduced to harmless nitrogen gas, and side waste products practically do not occur. In this paper the influence of nitrite ions on the process of denitrification was investigated. It is established that the denitrification process depends on the ratio between nitrate and nitrite concentration. The process is inhibited even at low nitrite concentration

BIODEGRADATION OF XENOBIOTICS

The compounds as 1, 2-dibromoethane, 1, 2-dichloroethane and phenol are ones of the most dangerous pollutants in the environment. 1, 2-Dibromoethane (DBE) is a synthetic organic chemical that is mainly used as a gasoline additive. It is also one of the widely used pesticide fumigants. 1,2-Dichloroethane is one of the most commonly used chlorinated industrial products and falls into the environment by using it as a chemical intermediate in the synthesis of a number of chlorinated hydrocarbons. Phenol is a waste product from the plastics, petroleum and pharmaceutical industries. There are different methods for treating wastewater containing the listed xenobiotics. Applied physicochemical methods are often economically ineffective and may cause other toxic products to occur. For this reason, microbiological treatment methods are preferred. We tested three different bacterial strains: Pseudomonas putida, Bradyrhizobium japonicum and Xanthobacter autotrophicus GJ10. In our studies for a period of 14 days with pre-adapted culture of Pseudomonas putida strain, we have achieved a degradation of 0.26 g/l of phenol in shaking flasks and a fed-batch process.. Over a period of 6 days, 1.2 g/l of 1,2 dibromethane was degraded using the Bradyrhizobium japonicum strain, and for 3 days Xanthobacter autotrophicus GJ10 degraded 0.9 g / l of 1,2-dichloroethane