Phenylurea herbicides induce cytogenetic effects in Chinese hamster cell lines

The intensive use of herbicides over the last few decades has caused a general increase of environmental pollution. It is thus very important to evaluate the possible genotoxic properties of these chemical compounds as well as identifying their mode of action. Phenylurea herbicides are selective agents widely used for the control of infestant plants. Of these herbicides, which are widely used in agriculture, we analysed four of the less intensively studied molecules. More precisely, we investigated the genotoxic effects of fenuron, chlorotoluron, diuron, and difenoxuron by analyses of chromosomal aberrations (CAs) and sister chromatid exchange (SCE) in exposed mammalian cells. We used the Chinese hamster ovary (CHO) and epithelial liver (CHEL) cell lines, endowed with the absence or the presence, respectively, of an enzymatic system to activate pro-mutagenic compounds. Our results show that all herbicides tested induce, at high concentrations, an increasing number of CAs in non-metabolising CHO cells. Instead, in the exposed CHEL cell line, the four herbicides induced CAs also at the lowest dose-level. In the CHEL cells, a statistically significant increase of SCE was also observed. The phenylurea herbicides showed direct genotoxic activity, but the cytogenetic effects were greatly enhanced after metabolic conversion. These data, together with other information on phenylurea herbicides, are of great interest from the environmental point of view, and for human health. In fact, intensive use of herbicides contaminates soil, surface water, groundwater and agricultural products, and thus should be taken in particular consideration not only for those initiatives to specifically protect exposed workers, but also to safeguard the health of consumers of agricultural products.     

Optimization of recombinant human nerve growth factor production in the psychrophilic Pseudoalteromonas haloplanktis

The optimization of production strategy is a very useful tool to attain high level of recombinant protein at a low cost. A promising biotechnological application of psychrophilic bacteria is their use as non-conventional host for the recombinant production of useful proteins. The lowering of the expression temperature can in fact facilitate the correct folding of heterologous proteins that accumulate in insoluble form as inclusion bodies when produced in Escherichia coli. An example of such "difficult" proteins is the human nerve growth factor (hNGF). The gene encoding the mature form of hNGF was expressed in the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 at 4 degrees C. Western blotting experiments demonstrated that the protein was produced in soluble form and translocated in the periplasmic space. Furthermore, an analytical gel filtration chromatography confirmed that the recombinant protein was largely in dimeric form. For a more efficient recombinant rhNGF production, the influence of cultivation operational strategies and growth conditions (medium composition, temperature, specific growth rate) on biomass yield and recombinant protein production was investigated in batch and chemostat cultivations. The highest product yield of soluble rhNGF (7.5mg(NGF)g(dryweight)(-1)) has been achieved in batch culture at 4 degrees C on Schatz medium with addition of tryptone and vitamins.     

Human chromosomal bands: nested structure,high-definition map and molecular basis

In this paper, we report investigations on the nested structure, the high-definition mapping, and the molecular basis of the classical Giemsa and Reverse bands in human chromosomes. We found the rules according to which the approximately 3,200 isochores of the human genome are assembled in high (850-band) resolution bands, and the latter in low (400-band) resolution bands, so forming the nested mosaic structure of chromosomes. Moreover, we identified the borders of both sets of chromosomal bands at the DNA sequence level on the basis of our recent map of isochores, which represent the highest-resolution, ultimate bands. Indeed, beyond the 100-kb resolution of the isochore map, the guanine and cytosine (GC) profile of DNA becomes turbulent owing to the contribution of specific sequences such as exons, introns, interspersed repeats, CpG islands, etc. The isochore-based level of definition (100 kb) of chromosomal bands is much higher than the cytogenetic definition level (2-3 Mb). The major conclusions of this work concern the high degree of order found in the structure of chromosomal bands, their mapping at a high definition, and the solution of the long-standing problem of the molecular basis of chromosomal bands, as these could be defined on the basis of compositional DNA properties alone.     

Psychiatric disorders and SLC6A4 gene variants: possible effects on alcohol dependence and alzheimer’s disease

Molecular Biology Reports - Serotoninergic system is one of the most important neurotransmission systems investigated in the field of psychiatry. Extensive evidence reveals how alterations of this...     

Serotonin and γ-Aminobutyric Acid Turnover After Injection into the Median Raphe of Substance P and D-Ala-Met-Enkephalin Amide

The raphe nuclei [which contain serotonin (5-HT) cell bodies] are also known to contain axons that store substance P, met-enkephalin, and gamma-aminobutyric acid (GABA). We have previously shown that GABA has a tonic inhibitory action on 5-HT turnover. To examine other possible interactions of these neuronal systems, we assessed the effect on 5-HT turnover of injecting substance P and 2-D-ala-met-enkephalin into the median raphe nucleus, and the effects of substance P on GABA turnover. Serotonin turnover was increased by 30% in the hippocampus after the injection of substance P (4 micrograms) into the median raphe, indicating an excitatory effect of substance P on the raphe-hippocampal system. Local injection of the metabolically stable metenkephalin analog 2-D-ala-met-enkephalin amide (10 micrograms) increased the hippocampal steady state content of 5-hydroxyindoleacetic acid (5-HIAA) by 60%. The data suggest an excitatory effect of met-enkephalin within the raphe nucleus. We attempted to estimate GABA turnover from the rate of disappearance of GABA after inhibition of glutamic acid decarboxylase by isoniazid and by the rate of accumulation of GABA after inhibition of GABA transaminase by gabaculine. Isoniazid, which is a competitive inhibitor, had too short and incomplete an action to be of use when injected intranuclearly. Gabaculine, which is an irreversible inhibitor, induced a rapid-onset increase in GABA content. This accumulation was linear up to 90 min. The injection fo gabaculine (80 ng) into the raphe increased GABA content by five times the control values, but hippocampal 5-HT and 5-HIAA contents were not significantly changed. Substance P injection increased the GABA turnover by 30%. Gabaculine seems a promising tool for detecting changes in GABA turnover.     

Identification of enzyme-producing thermophilic bacilli isolated from marine vents of Aeolian Islands (Italy)

Enzyme-producing thermophilic bacilli were isolated from different thermal sites located in and around Aeolian Islands (Italy) and characterised by both molecular and culture-based methods. Spore-forming bacteria with optimal growth from 45 to 70 °C were isolated from submarine vents and a geothermal well of Aeolian Islands (Italy). Eighteen selected strains were screened for extracellular enzyme presence by using nine substrates: Tween 20, Tween 80, tributyrin, soluble starch, xylan, dextran, carragenan, gelatine and casein. Sixteen isolates were able to grow at pH 9. The isolates were differentiated on the basis of restriction pattern of their amplified 16S rDNA (ARDRA) prior to 16S rRNA gene sequence analysis. On the basis of the most complete sequencing results strain V3 was identified asGeobacillus thermodenitrificans, most of isolates (10/14) was similar at high level (≥95%) to different reference strains of the speciesBacillus licheniformis. The remaining isolates, exhibiting sequence similarity below 95%, may represent novel species of the genusBacillus.