The TCLI locus on chromosome 14 band q32

C- and G-banding, silver staining, and cytofluorometric analysis of DNA content were carried out on two species of eels, Anguilla anguilla and A. rostrata, to compare them, to investigate the existence of sex chromosomes in both species, on which different authors disagree, and to understand the significance of the sex-independent variability found in one chromosome pair.

There is convincing evidence that the cyto.plasmnic domains of multisning receptors interact with guanine nucleotide-binding proteins (G proteins). What are the rules governing these interactions? In an attempt to answer this question, we focused our attention on mastoparan, an amphiphilic tetradecapeptide from wasp venom, and on nine of its variants, produced by sequence permutation, which have altered amphiphilicity or no amphiphilici at all. Mastoparan enhances the GTPase activity of recombinant G~a 5-fold in phospholipid vesicles. Like mastoparan, four of the synthetic variants can form amphiphilic a-helices and two of them indeed stimulate the GTPase activity of the G protein, whereas the other two have no effect. This confirms that the activation of certain G proteins by a number of peptides is mainly due to their cationic amphiphilicity. However, this structural feature is clearly not sufficient. The relative orientation ofthe positively charged residues as well as that of the hydrophobic side chains appear to be of fundamental importance. The other five peptides are not amphiphlc and do not enhance the rate of GTP hydrolysis. Surprisingly, three of them almost completely inhibit the G protein's intrinsic GTPase activity. This finding is of interest because of the possible role differential regulation of G protein activity can play in cellular functions.The guanine nucleotide-binding proteins (G proteins) that link cell surface receptors to cytosolic effectors in signal transduction comprise a family of apy heterotrimers associated with the plasma membrane. Upon activation by a liganded receptor the a-subunit binds GTP, dissociates from by, and interacts with one or more effectors (for recent reviews see refs. 1-4). Most known G protein-coupled receptors are characterized by seven hydrophobic transmembrane domains (multispanning receptors), but there is increasing evidence that indicates that certain receptors for growth factors, with a single transmembrane domain, also interact with G proteins (5).The G protein coupling sites ofthe multispanning receptors presumably are located in the second and third cytoplasmic loops (6-8). Synthetic peptides with sequences corresponding to segments of the cytoplasmic loops of the f2-adrenergic receptor have been tested for their effect on adenylate cyclase in erythrocyte membranes. Results suggest that parts of the second, third, and fourth intracellular loops interact with the G protein (9). In contrast, two peptides, comprising the N-and C-terminal 15 amino acids ofthe third intracellular loop of the P2-adrenergic receptor, stimulate the GTPase activity of a recombinant a-subunit of G, ( Because of its amphiphilic nature, MP assumes an a-helical structure when bound to phospholipids, with the positively charged residues exposed to the aqueous medium (13). Presumably, the multispanning receptor regions that interact with G proteins also form cationic amphiphilic a-helices (14).Are there interactions that do not cause stimulation of G protein activity and, ins...

A strain of Pseudomonas sp., SMP1, isolated from a soil sample collected in the Monterotondo area (Rome), secreted isoamylase activity into the culture medium. The enzyme was purified and optimal reaction and stability conditions were determined by varying pH and temperature. The chemico-physical properties of the enzyme were similar to those of the isoamylase purified in Japan more than 20 years ago from 'Pseudomonas amyloderamosa' strain SB15. A genomic library of SMP1 was prepared in Escherichia coli using pUC12 as vector. Two isoamylase-producing colonies were identified out of 6300 screened. The hybrid plasmids isolated from the two clones showed common restriction patterns. The chromosomal portion of one of these plasmids (pSM257) was completely sequenced. Comparison between the deduced amino acid sequence of the isoamylase and the published sequences of other amylolytic enzymes showed the presence of conserved domains.

Peripheral neurotoxicity is a severe side effect of several effective antineoplastic drugs. Different attempts have been previously performed in order to reduce the neurotoxicity of antineoplastic compounds, but so far an effective neuroprotective treatment is not available. Acetyl‐l‐carnitine (ALC) is a natural occurring compound with a neuroprotective activity in several experimental paradigms and in clinical use for the treatment of painful neuropathies. In this study we have tested in two rat models the hypothesis that ALC may have a protective role on cisplatin‐ and paclitaxel‐induced neuropathy. Preliminary in vitro and in vivo experiments in different tumor systems indicated the lack of interference of ALC in the antitumor effects of cisplatin and paclitaxel. ALC co‐treatment was able to significantly reduce the neurotoxicity of both cisplatin and paclitaxel in well‐established rat models and this effect was correlated with a modulation of the plasma levels of nerve growth factor (NGF) in the cisplatin model. The protective effect of ALC was confirmed also in in vitro studies on differentiated rat pheochromocytoma PC12 cells, where ALC treatment counteracted the paclitaxel and cisplatin‐induced cell damage, as measured by reduction of neurite elongation. In a search for the mechanism(s) of ALC neuroprotection, the transcriptional profile of gene expression in PC12 cells determined by microarray analysis indicated that ALC, in the presence of NGF, was able to modulate various genes relevant in the tissue‐specific toxicity, such as NGFI‐A. Moreover, we observed that labeled acetyl groups derived from ALC were transferred into histones and that cells co‐treatment with NGF and ALC increased the level of histones H4 acetylation. These findings suggest that up‐regulation of genes implicated in the protection against specific damage induced by neurotoxic agent may be the result of modulation of histone acetylation mediated by transfer of ALC acetyl groups. Overall, these results provide the first evidence that ALC is a neuroprotective agent acting through a novel mechanism that appears to be important for counteracting the chemotherapy‐induced neurotoxicity secondary to cisplatin and paclitaxel treatment.