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91.
    
Marine biotoxins synthesized by Harmful Algal Blooms (HABs) represent one of the most important sources of contamination in marine environments as well as a serious threat to fisheries and aquaculture-based industries in coastal areas. Among these biotoxins Okadaic Acid (OA) is of critical interest as it represents the most predominant Diarrhetic Shellfish Poisoning biotoxin in the European coasts. Furthermore, OA is a potent tumor promoter with aneugenic and clastogenic effects on the hereditary material, most notably DNA breaks and alterations in DNA repair mechanisms. Therefore, a great effort has been devoted to the biomonitoring of OA in the marine environment during the last two decades, mainly based on physicochemical and physiological parameters using mussels as sentinel organisms. However, the molecular genotoxic effects of this biotoxin make chromatin structure a good candidate for an alternative strategy for toxicity assessment with faster and more sensitive evaluation. To date, the development of chromatin-based studies to this purpose has been hampered by the complete lack of information on chromatin of invertebrate marine organisms, especially in bivalve molluscs. Our preliminary results have revealed the presence of histone variants involved in DNA repair and chromatin specialization in mussels and clams. In this work we use this information to put forward a proposal focused on the development of chromatin-based tests for OA genotoxicity in the marine environment. The implementation of such tests in natural populations has the potential to provide an important leap in the biomonitoring of this biotoxin. The outcome of such monitoring may have critical implications for the evaluation of DNA damage in these marine organisms. They will provide as well important tools for the optimization of their harvesting and for the elaboration of additional tests designed to evaluate the safety of their consumption and potential implications for consumer's health.  相似文献   
92.
    
Teratocytes are specialized cells released by parasitoid wasps into their hosts. They are known for producing regulatory molecules that aid the development of immature parasitoids. We have recently reported the primary structures of cystine-rich peptides, including some containing inhibitor cystine knot (ICK) motifs, produced by teratocytes of the parasitoid Cotesia flavipes (Hymenoptera: Braconidae). ICKs are known for their stability and diverse biological functions. In this study, we produced four putative ICK peptides from the teratocytes of C. flavipes using solid-phase peptide synthesis or recombinant expression in E. coli, and investigated their functions on host immune modulation as well their potential to impair the development of two lepidopterans after ingestion of the peptides. In addition, the peptides were assayed against pathogens and human cells. The peptides did not influence total hemocyte count but suppressed cellular immunity, detectable as a reduction of hemocyte encapsulation (CftICK-I, CftICK-II, CftICK-III) and spread indexes (CftICK-IV) in the host. None of the peptides influenced the activities of prophenoloxidase and phenoloxidase in the hemolymph of larval Diatraea saccharalis (Lepidoptera: Crambidae). CftICK-I and CftICK-II with previously unknown function showed antifungal activity against Candida albicans but were non-toxic to human cells. CftICK-I, CftICK-II, and CftICK-III increased larval mortality and reduced leaf consumption of D. saccharalis, a permissive host for C. flavipes. The CftICK-III also increased larval mortality and reduced leaf consumption of Spodoptera frugiperda (Lepidoptera: Noctuidae), a non-permissive host for C. flavipes. This study highlights biological functions and biotechnological potential of ICK peptides from the teratocytes of C. flavipes.  相似文献   
93.
Seven new 15-keto pregnane glycosides, namely Stemmosides E--K, were isolated from Solenostemma argel. Stemmosides E--J are characterized by the occurrence of an uncommon 14 beta proton configuration while stemmosides E and F possess in addition a rare enolic function in C-16. On the other hand, stemmosides G-J display an unusual C-17 alpha side chain. Their structures were established by ESI-MS and NMR experiments. Moreover, the effect of these compounds on the VEGF-induced in Kaposi's sarcoma cell proliferation was tested. Results indicated that all the compounds reduced the cell proliferation in a dose dependent manner.  相似文献   
94.
    
The role of the N-terminal sequence of myeloperoxidase in the intracellular targeting was examined by using glycosylated lysozyme as a reporter. A fusion protein was constructed in which the presequence residues −18 through −6 of the lysozyme moiety had been replaced by residues 1–158 of prepromyeloperoxidase. Expression of the fusion protein in Chinese hamster ovary cells demonstrated its partial secretion and partial intracellular retention. The latter was accompanied by trimming the myeloperoxidase prosequence off the lysozyme moiety. The rate of the retention of the lysozyme fusion protein was higher than that of glycosylated lysozyme that had been expressed in cells transfected with cDNA of glycosylated lysozyme. The retention was insensitive to NH4Cl. In the secreted protein, lysozyme contained predominantly complex oligosaccharides as demonstrated by a proteolytic fragmentation in vitro and resistance to endo-β-N-acetylglucosaminidase H. In contrast, when targeted to lysosomes, the lysozyme moiety of the fusion protein contained predominantly mannose-rich oligosaccharides. In baby hamster kidney cells, the trimming of the oligosaccharides in the lysozyme fragment was less vigorous, and a selective targeting of molecules bearing mannose-rich oligosaccharides to lysosomes was more apparent than in Chinese hamster ovary cells. In the presence of monensin, the formation of complex oligosaccharides in the fusion protein and its secretion were strongly inhibited, whereas the intracellular fragmentation was not. We suggest that the prosequence of myeloperoxidase participates in the intracellular routing of the precursor and that this routing operates on precursors bearing mannose-rich rather than terminally glycosylated oligosaccharides and diverts them from the secretory pathway at a site proximal to the monensin-sensitive compartment of the Golgi apparatus. J. Cell. Biochem. 71:158–168, 1998. © 1998 Wiley-Liss, Inc.  相似文献   
95.
It is universally accepted that lifestyle interventions are the first step towards a good overall, reproductive and sexual health. Cessation of unhealthy habits, such as tobacco, alcohol and drug use, poor nutrition and sedentary behavior, is suggested in order to preserve/improve fertility in humans. However, the possible risks of physical exercise per se or sports on male fertility are less known. Being “fit” does not only improve the sense of well-being, but also has beneficial effects on general health: in fact physical exercise is by all means a low-cost, high-efficacy method for preventing or treating several conditions, ranging from purely physical (diabetes and obesity) to psychological (depression and anxiety), highly influencing male reproduction. If male sexual and reproductive health could be positively affected by a proper physical activity, inadequate bouts of strength – both excessive intensity and duration of exercise training – are more likely to have detrimental effects. In addition, the illicit use of prohibited drugs (i.e. doping) has reached pandemic proportions, and their actions, unfortunately very often underestimated by both amateur and professional athletes, are known to disrupt at different levels and throughout various mechanisms the male hypothalamic-pituitary-gonadal axis, resulting in hypogonadism and infertility.  相似文献   
96.
Follicle diameter deviation is defined as the beginning of the differential change in growth rates between the largest and next largest follicles subsequent to wave emergence and is considered a key component of follicle selection. Follicle selection has been extensively studied in European breeds of cattle (Bos taurus) but has not been critically studied in Zebu breeds (Bos indicus). The objectives of the present study were to determine and compare the morphological characteristics of deviation associated with the first post-ovulatory wave (Wave 1) of the estrous cycle in Nelore heifers (n=8) and nonlactating cows (n=11). Beginning on the day of ovulation (day 0), the three largest follicles (F1-F3, respectively) were individually tracked every 12 h for 6d using transrectal ultrasonography. In individual animals, deviation was determined graphically using visual inspection of the diameter profiles of F1, F2 and sometimes F3 (observed deviation) and mathematically using segmented regression analysis of the diameter differences between F1 and F2 or sometimes F3 (calculated deviation). Mean day of emergence of Wave 1 when F1 reached >3 mm (approximately 1 d after ovulation) and growth rate of F1 during deviation (approximately 1.4 mm/d) were not significantly different between heifers and cows. The results of determining the beginning of deviation within heifers and cows using the observed and calculated methods were not significantly different. Averaged over both methods, diameter deviation occurred 2.8 d after ovulation when F1 reached 5.7 mm in heifers, and 2.4 d after ovulation when F1 reached 6.1 mm in cows. In conclusion, the emergence of Wave 1 and growth rates and diameters of the future dominant follicles at the beginning of deviation were similar in Nelore heifers and nonlactating cows, regardless of the methods used to determine deviation. Relative to Holstein cattle, emergence of Wave 1 appeared to occur about 1 d later and diameter of the future dominant follicle at the beginning of deviation was about 2 mm smaller in Nelore.  相似文献   
97.
  总被引:23,自引:0,他引:23  
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98.
99.

Background  

Water coolers are popular in office buildings and commercial stores and the quality of this source of drinking water has the potential to cause waterborne outbreaks, especially in sensitive and immunocompromised subjects. The aim of this study was to determine the quality of water plumbed in coolers from commercial stores in comparison with tap water in Italy.  相似文献   
100.
Naltrexone (NTX) is widely used to prevent relapse of opioid-dependent patients but its association with insomnia and "hyperexcitability" can result in treatment withdrawal. We evaluated whether NTX combined with the benzodiazepine prazepam was more effective than NTX in keeping patients opioid-free. We determined the relapse rate over 6 months in 56 opioid-dependent subjects, divided into 4 equal groups. All groups received psychological support and underwent urine tests for drug metabolites twice weekly. Group 1 did not receive pharmacological treatment (controls). Group 2 received NTX alone (one 50-mg tablet daily); group 3 received NTX (one 50-mg tablet daily) plus placebo (one tablet twice daily); and group 4 received NTX (one 50-mg tablet daily) plus prazepam (one 10-mg tablet twice daily). Ten patients of group 1 relapsed within 3 months, one after 6 months and three remained opioid-free. Six patients of group 2 relapsed within three months, two after 6 months, and six remained opioid-free. Seven patients of group 3 relapsed three months, one after 6 months and six patients remained opioid-free. In group 4, one patient relapsed within 3 months and one patient after 6 months; 12 patients of this group remained opioid-free. At urine tests, a significantly higher percent patients of group 4 remained free of Delta(9)-tetrahydrocannabinol versus patients of groups 2 and 3. In conclusion, many patients remained opioid-free on NTX alone or combined with prazepam, with a significant advantage for the NTX plus prazepam group.  相似文献   
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