Giovanni Vailati
University of Milan
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Featured researches published by Giovanni Vailati.
Chemosphere | 2001
Andrea Binelli; Renato Bacchetta; Giovanni Vailati; Silvana Galassi; Alfredo Provini
Zebra mussel (Dreissena polymorpha) is commonly used as contaminant bioindicator in Europe and North America. We used the zebra mussel to follow DDT pollution trends from 1996 to 1997 in Pallanza bay, Lake Maggiore, near the inlet of the River Toce, after a DDT-manufacturing plant discharging residues into a tributary of the River Toce had closed down. DDT contamination fell off sharply outside the bay, but tissue concentrations of the parent compound and residues remained high in molluscs sampled within the bay a year later. Molluscs collected in Pallanza bay in June 1997 released gametes earlier than those sampled at a nearby reference station. Histological studies showed that a significant percentage of these specimens showed marked oocyte degeneration suggesting that DDTs have endocrine-disrupting effects in this species.
Science of The Total Environment | 2008
Renato Bacchetta; Paride Mantecca; Manuela Andrioletti; Claudio Vismara; Giovanni Vailati
Embryotoxic effects of Carbaryl (CB), a widely used carbamate insecticide, was evaluated by modified Frog Embryo Teratogenesis Assay-Xenopus (FETAX), coupled with a histopathological screening of the survived larvae. X. laevis embryos were exposed to 1, 2, 4, 8, 16 and 24 mg/L CB from stage 8 to stage 47. From an estimated LC50 of 20.28 mg/L and TC50 of 8.43 mg/L a TI of 2.41 was derived, indicating that CB is to be considered teratogenic for X. laevis embryos. The most characteristic terata, classified as abnormal tail flexure, involved a significant percentage of larvae from 1 mg/L CB onward, reaching 100% at 24 mg/L CB. Histopathological screening revealed tail musculature and notochord as the main targets for CB. Skeletal muscle lesions consisted of myotomes reduced in size, showing myocytes with disorganized contractile systems and irregular myosepta, coupled with disarranged myocyte apexes. Notochords from CB exposed larvae appeared wavy or bent, with irregular connective sheaths and histologically characterized by protrusions of fibrous matrix and inclusions of ectopic cell masses. This axial-skeletal damage was hypothesized to be related both to the inhibition of acetylcholinesterase, with consequent muscular tetanic spasms, and to disorders in the organization of the connective tissue matrix surrounding the notochord.
The FASEB Journal | 1997
Aldo Milzani; Isabella Dalle-Donne; Giovanni Vailati; Roberto Colombo
The molecular mechanism (or mechanisms) at the basis of paraquat (PQ) (a widely used herbicide) toxicity is far from being fully understood. Until now, two main points of view have emerged: 1) PQ‐related cell injuries could be mediated by toxic oxygen free radicals coming from the metabolism of the herbicide by the microsomal enzyme system, and/or 2) PQ, by inducing mitochondrial swelling and breakage, could cause troubles in cell energy charge, then driving the cell to death. Recently, some of cytoskeletal structures (microtubules and microfilaments) have been proposed as further PQ cell targets. The microfilament system in particular seems to be markedly affected by the herbicide, but so far no direct evidence associates PQ to actin damage. In this study, experimental data are presented concerning the direct effect of PQ on actin dynamics in solution. We demonstrate that actin selectively binds PQ; moreover, PQ induces the formation of actin sopramolecular structures in depolymerizing medium (G‐buffer). Furthermore, by the interactions with F‐actin cross‐linking proteins (α‐actinin and filamin), FITC‐phal‐loidin, and myosin subfragment 1 (S1), it is demonstrated that PQ‐induced actin aggregates are undoubtedly built up by F‐actin. Electron micrographs showed that PQ‐induced actin polymers are very short and tend to aggregate one to another. This mutual cohesion leads to the steric blockage of polymer growing ends as suggested by nucleated actin polymerization assays. Sonication, by releasing F‐actin fragments from short polymer aggregates, allows actin polymer ends to regain their growing ability.—Milzani, A., DalleDonne, I, Vailati, G., Colombo, R. Paraquat induces actin assembly in depolymerizing conditions. FASEB J. 11, 261‐270 (1997)
Experimental and Molecular Pathology | 1988
Roberto Colombo; Anna Necco; Giovanni Vailati; Aldo Milzani
Doxorubicin (Adriamycin), one of the most potent antibiotics used in tumor chemotherapy, shows many undesirable side effects. We studied the effect of different drug concentrations on the biochemistry of cell motility and, in particular, on potassium-induced actin polymerization. It is well known, in fact, that the actin aggregational status could dramatically influence many cell motility manifestations. Our results clearly show that stoichiometric and substoichiometric amounts of doxorubicin negatively influence actin polymerization by inhibiting both the filament growth and the polymer amount at steady-state; the balance between the two different effects seems to be in relation to the drug concentration. The obtained results could explain some of the doxorubicin effects previously observed in vivo.
Cell Biology International Reports | 1984
Roberto Colombo; Anna Necco; Giovanni Vailati; Bruna Saracco; Aldo Milzani; Giorgio Scarì
In vitro experiments on actin polymerization in the presence of doxorubicin show that the rate of salt-induced actin assembly is negatively affected by the drug. The decreased amount of actin monomers keeping their ability to self-interact to give F actin (microfilaments) probably explains the reduction of assembly value. Drug action is dose-dependent and various discrepancies are explained by the limitations of the techniques used.
Archiv Fur Hydrobiologie | 2003
Paride Mantecca; Giovanni Vailati; Renato Bacchetta
Histological techniques were used to monitor Dreissena polymorpha reproductive biology during 2001 in Lake Maggiore (N. Italy). Considering the DDT pollution which occurred during the mid 1990s in this lake and the high contamination level registered in 2001, we focused on the course of spawning events in zebra mussels and possible modified reproductive behavior induced by this pollution. Specimens were collected from the lake at Baveno as the polluted station, and at Villa Taranto as the control site. At Villa Taranto, morphological analyses of gonadal changes showed a gamete developing and maturing period until April, spawning phases from May to August, the restart of gametogenesis in females and an inactive period in males, immediately after the end of spawnings. This pattern was perturbed at Baveno where the mussels showed a delay in oocyte maturation with a significant percentage of specimens showing oocyte degeneration. Moreover, the onset of gamete release seemed to shift from May to July in the males at Baveno. Our findings agreed with the well recognized endocrine disrupting properties of DDT, even though the physiological mechanisms involved must be studied further.
Cell Biology International Reports | 1983
Anna Necco; Giovanni Vailati; Roberto Colombo
The inhibition of neural tube closure in early chick embryos explanted in vitro by News technique was used as a model to study the possible involvement of actin polymerization during doxorubicin treatment. The investigation was performed with indirect immunofluorescence staining, fluorescence staining with NBD-Ph, and DNase I inhibition activity. 8 x 10(-6) M doxorubicin induces alteration in the distribution of actin fluorescence on neural tube and in CEF cell cytoskeleton, and an appreciable increase in the critical concentration of monomeric actin as measured in cell extracts.
Invertebrate Reproduction & Development | 2001
Giovanni Vailati; Renato Bacchetta; Paride Mantecca
Summary The reproductive biology of the zebra mussel Dreissena polymorpha was studied during 1999 in a natural population living in Lake Como (N. Italy), with particular reference to the differences in behavior between young and adult mussels. Histological analysis of gonads was used to study the gametogenic cycles and to evaluate when the young reached sexual maturity. Signs of active gametogenesis were detected in ≥4 mm shell length mussels. Mature gametes and the first spawning events were observed in ≥5 mm males and in ≥6 mm females. The gonad feature of ≥7 mm mussels was similar to that of the adults. Size frequency distributions revealed that the new generation (0+) first spawned in the year following birth, but only after winter. The length of larval time seemed to vary greatly depending on the spawning period, in addition to the environmental conditions. The first settled mussels ≥500 μm in shell length were observed 3–4 months after the first depositions. Water temperature seemed to be the most important factor which regulated sexual phenomena of both young and adult mussels. Its role in the onset of the spawning events was confirmed, but it is important to point out that temperature is not enough to trigger reproduction since gamete release is impossible without sufficient energy, especially for young mussels.
Italian Journal of Zoology | 1990
Guido Tosi; Giovanni Vailati; Serena Arduino; Guido Pacchetti
Abstract The repertoire of behaviour of chamois (Rupicapra rupicapra rupicapra) includes two patterns (horning and marking) related to interactions of the horns with a substratum. To determine the role of supraoccipital glands in such interactions, a histological analysis of 173 glands from chamois culled in October‐December in the central Alps was carried out. For each gland, the degrees of development and secretory activity were evaluated and correlated with sex, age and date of collection, to obtain a clear description of the functional nature of these organs during the breeding season. It was found that the amount of secretion depends on the development of the glands, which is greater in males than in females and is maximal in adult males (4 years old or more) and in subadult females (2–3 years old). That there is a trend in the development to non‐linear dependence on the time dimension within the breeding period was indicated by finding highest degrees of development concentrated in adult males at th...
Italian Journal of Zoology | 2007
Renato Bacchetta; Paride Mantecca; L. Lattuada; F. Quaglia; Giovanni Vailati; M. Apollonio
The carpal organ is a glandular complex implicated in scent communication. To investigate its ethological significance, morpho‐functional evaluations were conducted on 67 glands collected from animals of different ages and sex during the 2002 hunting season (October–December) in the Bergamo district, Northern Italy. All samples were histologically and morphometrically examined to determine gland surface and thickness, number of secretory tubules per area and outer diameter of the tubules. Comparative analyses revealed significant differences in the above parameters between sub‐adults and adults for both sexes, but no differences were found between adult males and females. However, when all specimens were pooled, males revealed more developed and functional glands than females, with the oldest males having the highest values of gland surface, gland thickness and tubule diameter. Our findings suggest that this organ plays a relevant role in social communication by producing chemical signals involved in territorial definition as well as reproduction.