Biomedical subjects

G Manicardi

Publications and source records attributed to G Manicardi.

At least 19 recordsLinked to original sources

PubMed2004

Study of two bacteriocins produced by Enterococcus casseliflavus and Ent. faecalis.

AIMS: The antimicrobial activity of two plasmid-borne bacteriocins produced by Enterococcus casseliflavus IM 416K1 and Ent. faecalis IM 388C and their mating transferability were studied. METHODS AND RESULTS: Both bacteriocins showed antibacterial activity against taxonomically related micro-organisms and Listeria monocytogenes but differ for heat sensitivity, antimicrobial titre, molecular size and class of affiliation. The transferability by mating of the antibacterial properties from producers to Enterococcus faecalis JH2-2 revealed that the bacteriocin-phenotype was linked in both strains to genes located on a 34 MDa plasmid. This result was confirmed by loss of antibacterial activity and immunity after curing treatment. CONCLUSIONS: Restriction analysis has shown a different profile of the two conjugative plasmids. Enterocin 416K1 and Enterocin 388C could represent natural antilisterial agents to use in food technology. SIGNIFICANCE AND IMPACT OF THE STUDY: The transferability of the 34 MDa conjugative plasmids might be considered a possibility for the study of bacteriocins expression in bacterial hosts different from the native strains.

Anti-Bacterial Agents↗

PubMed2004

Glycopeptide-resistance transferability from vancomycin-resistant enterococci of human and animal source to Listeria spp.

AIMS: The glycopeptide-resistance transferability from vancomycin-resistant enterococci (VRE) of clinical and animal origin to different species of Listeria was investigated. METHODS AND RESULTS: Of 36 matings, performed on membrane filter, the glycopeptide resistance was successfully transferred in six attempts, five with donors of animal origin and only one with donors from clinical source. The acquired glycopeptide resistance in Listeria transconjugants was confirmed by the presence of the conjugative plasmid band and by the amplification of the 732-bp fragment of vanA gene in transferred plasmids. CONCLUSIONS: Despite the lower number of bacteria used in this study, the source of enterococci influenced the outcome of mating. Moreover transferred VanA plasmid induced a different expression in Listeria transconjugants, suggesting that gene expression might be influenced by species affiliation of recipients. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data strengthen the opinion that enterococci are an important source of resistance genes for Listeria via the transfer of movable genetic elements. As these strains are commonly found in the same habitats, a horizontal spread of glycopeptide resistance in Listeria spp. could be possible.

Animals↗

PubMed2003

Bacteriocin-producing Enterococcus casseliflavus IM 416K1, a natural antagonist for control of Listeria monocytogenes in Italian sausages ("cacciatore").

The bacteriocinogenic Enterococcus casseliflavus IM 416K1 (Bac+) isolated from Italian sausages or its bacteriocin Enterocin 416K1, with strong anti-listerial activity, were used in trials to evaluate the effect on Listeria monocytogenes NCTC 10888 in artificially inoculated Italian sausages ("cacciatore"). In trials with Enterocin 416K1 added, L. monocytogenes showed a significant reduction as compared to the control inoculated with L. monocytogenes alone. The elimination of L. monocytogenes was only obtained in sausages added with E. casseliflavus IM 416K1 Bac+.

Animals↗

PubMed2002

Enterocin 416K1, an antilisterial bacteriocin produced by Enterococcus casseliflavus IM 416K1 isolated from Italian sausages.

Enterococci (118) from Italian sausages were tested for the production of antimicrobial substances. Of these, 7.6% showed antibacterial activity against one or several closely related microorganisms used as indicators. Enterococcus casseliflavus IM 416K1 in particular produced a bacteriocin (Enterocin 416K1) with strong anti-listerial antagonistic activity. The bacteriocin withstood heating at 90 degrees C for 120 min and storage at 4 degrees C for 6 months. The mode of action was identified as bactericidal. The crude activity of Enterocin 416K1 was linked to a molecule with an apparent molecular weight smaller than 5 kDa. Plasmid analysis of E. casseliflavus IM 416K1 revealed the presence of four plasmids with different molecular weights (34, 11, 7 and 3.3 MDa). All the Bac- variants produced by curing experiments showed loss of the single plasmid of 34 MDa. Bacteriocin activity and immunity production may be linked to genes located on that same plasmid.

Animals↗

PubMed2001

Detection and preliminary characterization of a bacteriocin (plantaricin 35d) produced by a Lactobacillus plantarum strain.

Lactic acid bacteria (134) from Italian sausages were tested for the production of antimicrobial substances (bacteriocins). Six percent of these showed antibacterial activity against one or several closely related microorganisms used as indicators. Lactobacillus plantarum 35d in particular produced a bacteriocin of high activity (320 AU ml(-1)) and a wide range of antimicrobial activity including S. aureus, L. monocytogenes, and A. hydrophila. The bacteriocin withstood heating at 80 degrees C for 120 min and storage at 4 degrees C for 6 months. The mode of action was identified as bactericidal. The apparent molecular weight of the bacteriocin extracted with n-butanol was estimated to be 4.5 kDa.

Animals↗

PubMed2000

Sperm decondensation during fertilisation in the mouse: presence of DNase I hypersensitive sites in situ and a putative role for topoisomerase II.

In this study our aim was to characterise the presence and the role of DNA alterations during sperm decondensation in the mouse. To visualise the changes during decondensation we investigated for the presence of DNase I hypersensitive sites in situ and for a putative role for topoisomerase II by examining the effect of teniposide, a topoisomerase II inhibitor, during fertilisation. In situ nick translation without the previous addition of DNase I failed to reveal the presence of endogenous nicks in decondensing sperm and pronuclei whereas preincubation of fixed oocytes with DNase I indicated that decondensing sperm were sensitive to this enzyme. Addition of 100 microM teniposide did not completely inhibit pronuclei formation but its addition to the fertilisation medium did lead to the presence of endogenous DNA nicks in decondensing sperm. These observations suggest that DNase I hypersensitivity during sperm decondensation is related to the dramatic conformational changes that the chromatin undergoes during the decondensation process, in which topoisomerase II may be implicated.

Animals↗

PubMed1999

Origin of DNA damage in ejaculated human spermatozoa.

The molecular basis of many forms of male infertility is poorly defined. One area of research that has been studied intensely is the integrity of the DNA in the nucleus of mature ejaculated spermatozoa. It has been shown that, in men with abnormal sperm parameters, the DNA is more likely to possess strand breaks. However, how and why this DNA damage originates in certain males and how it may influence the genetic project of a mature spermatozoon is unknown. Two theories have been proposed to describe the origin of this DNA damage in mature spermatozoa. The first arises from studies performed in animal models and is linked to the unique manner in which mammalian sperm chromatin is packaged, while the second attributes the nuclear DNA damage in mature spermatozoa to apoptosis. One of the factors implicated in sperm apoptosis is the cell surface protein, Fas. In this review, we discuss the possible origins of DNA damage in ejaculated human spermatozoa, how these spermatozoa arrive in the ejaculate of some men, and what consequences they may have if they succeed in their genetic project.

Animals↗

PubMed1999

Antimicrobial properties and morphological characteristics of two Photorhabdus luminescens strains.

The biological properties of two Photorhabdus luminescens isolates (MU1 and MU2) of environmental source and the activity of antimicrobial agar diffusible agents (AADA) produced by the same are reported. With regard to cultural features, two variant forms for P. luminescens MU1 and three for P. luminescens MU2 (including an intermediate phase I-like form) have been found. These three forms differ in biological and biochemical properties: beta-lactamase, urease, bioluminescence and antimicrobial agar diffusible substance production associated with the phase I form, were less evident in the intermediate phase I-like MU2 and were absent in phase II form. Antimicrobial activity was present in both strains, with the production of a large amount of a diffusible compound with a wide spectrum of action against bacteria of other genera; a reduced activity against correlated species was also observed. Examination by electron microscopy of MU1 and MU2 purified broth cultures revealed the presence of particles belonging to the class of the phage tail-like bacteriocins, described in recent studies as responsible for antibacterial activity against correlated bacteria, a result never confirmed "in vitro". A plasmid of 21 Mdal was observed in all the form variants of P. luminescens MU2, suggesting that plasmids are not involved in the transition from primary to secondary phase; no plasmid was detected in P. luminescens MU1.

Bacteriocins↗

PubMed1998

Sperm nuclear DNA damage and altered chromatin structure: effect on fertilization and embryo development.

In the first part of this report we investigate whether chromatin anomalies in human spermatozoa can influence fertilization after intracytoplasmic sperm injection (ICSI). We have examined the sperm chromatin packaging quality using the chromomycin A3 (CMA3) fluorochrome and the presence of DNA damage in spermatozoa using in-situ nick translation. When comparing the spermatozoa of patients undergoing in-vitro fertilization (IVF) and ICSI distinct differences are evident in that ICSI males have a higher CMA3 fluorescence, indicating spermatozoa with loosely packed chromatin, and more spermatozoa containing endogenous DNA nicks. When examining the unfertilized oocytes of ICSI patients we found that men who had a high percentage of anomalies in their chromatin, i.e. > 30% CMA3 fluorescence and > 10% nicks, had more than double the number of unfertilized oocytes containing spermatozoa that had remained condensed. The observation that failed fertilized oocytes, injected with spermatozoa from patients with a higher percentage of sperm nuclear anomalies, contain more condensed spermatozoa indicates that a selection process against these spermatozoa may be in place at the time of fertilization. In the second part of the study we show that spare ICSI embryos have significantly lower rates of development to the blastocyst stage compared with those developed after routine IVF. These results show that a greater understanding of the molecular basis of male infertility is therefore needed to broaden our knowledge on the effect that abnormal spermatozoa have on fertilization and embryo development.

Cell Nucleus↗

PubMed1997

Relevance of clinical and laboratory findings in the diagnosis of cytomegalovirus encephalitis in patients with AIDS.

A retrospective evaluation was conducted in patients with AIDS and an autopsy diagnosis of cytomegalovirus (CMV) encephalitis to determine the relevance of clinical and laboratory findings in establishing a diagnosis. On autopsy of 100 patients, CMV encephalitis was diagnosed in 13 patients; eight had periventricular CMV encephalitis, four micronodular CMV encephalitis, and one both conditions. Seven patients had had a CMV infection previously (6 cases of retinitis, 1 case of colitis), and at the onset of encephalitis all of them were receiving a maintenance dose of ganciclovir. Examination of the CSF showed specific changes in patients with periventricular encephalitis. CT revealed no characteristic findings, while MRI showed an increased signal intensity on T2 weighted images. CMV DNA amplification by nested PCR was performed in nine patients with CMV encephalitis; PCR was positive in eight patients whose CSF was collected during CMV encephalitis, and negative in one patient whose CSF was collected six months before death. In conclusion, some clinical findings suggest a presumptive diagnosis, especially of periventricular encephalitis, and nested PCR appears to be a reliable and rapid technique for making an antemortem diagnosis.

AIDS-Related Opportunistic Infections↗

PubMed1996

Use of the guanine-cytosine (GC) specific fluorochrome, chromomycin A3, as an indicator of poor sperm morphology.

PURPOSE: We have previously postulated that the chromomycin A3 (CMA3) fluorochrome allows an indirect visualization of sperm chromatin packaging quality and partially denatured sperm DNA. In this study we investigate the relationship between CMA3 positivity and sperm morphology. We also present data on the association between sperm morphology and the presence of endogenous nicks in sperm DNA. METHODS: Semen samples were examined from 81 males of the couples who were consulting for infertility treatment. CMA3 fluorescence was assessed for all samples, while in 24 sperm samples we also examined for the presence of endogenous nicks in the sperm DNA. RESULTS: When sperm morphology was less than 20% normal in a patient, the level of CMA3 fluorescence and presence of endogenous nicks were significantly higher than in patients with a higher incidence of morphologically normal sperm. CONCLUSIONS: CMA3 could be used as an adjunct to the assessment of morphology as an evaluation method for poor sperm. Its value in predicting fertilizing ability when using either SUZI or ICSI awaits to be answered.

Biomarkers↗

PubMed1996

Sperm chromatin anomalies can influence decondensation after intracytoplasmic sperm injection.

In this study we investigated whether morphology and chromatin anomalies in human spermatozoa can influence fertilization after intracytoplasmic sperm injection (ICSI). We examined unfertilized oocytes, using the fluorochrome Hoechst 33342, to determine whether a relationship exists between failure of fertilization and sperm chromatin quality. Sperm chromatin packaging quality was assessed using the chromomycin A3 (CMA3) fluorochrome, and the presence of DNA damage in spermatozoa, using in-situ nick translation, Normal males present sperm parameters with a normal morphology of > 20%, CMA3 fluorescence of < 30% and exhibit endogenous nicks in < 10% of their spermatozoa. When patients were separated according to these values no difference was observed in their fertilization rates after ICSI. When the unfertilized ICSI oocytes were examined, we found that patients with CMA3 fluorescence of <30% and nicks in < 10% of their spermatozoa had only 17.5 and 21.6% respectively of their unfertilized oocytes containing spermatozoa that remained condensed. In contrast, patients with higher CMA3 and nick values had a significantly higher number, 41.2 and 48.9%, of their unfertilized oocytes containing condensed spermatozoa. sperm morphology did not show any such pattern. The percentage of spermatozoa which had initiated decondensation in unfertilized oocytes was not influenced by morphology, CMA3 fluorescence or nicks. In light of these results we postulate that poor chromatin packaging and/or damaged DNA may contribute to failure of sperm decondensation after ICSI and result in failure of fertilization.

Adult↗

PubMed1996

[Sudden and unusual onset of penile plastic induration in 2 patients neurosurgically treated for pituitary macroadenoma].

Induratio penis plastica (IPP) or Peyronie disease is characterized by the developing of fibrotic plaques in the tunica albuginea of penis, that in the latter stages can lead to impotence. The etiology of this disease is still unknown even if various factors such as inflammation, autoimmunity or traumas are involved. Usually it occurs after 40 years of age, even if cases in young patients have been described. The onset of IPP can be acute in about 50% of the patients, while in the others it is characterized by a chronic but progressive progress. In this work, we describe the cases of two patients 52 and 66 years old, who arrived to our department for a decrease of libido and sexual potency in the last months. The patients were not smokers and took no drugs and they had never complain symptoms and signs of IPP. In both subjects an endocrine pattern compatible with partial hypopituitarism was present and in the first patient it was associated with an ACTH-dependent hypercortisolism. Pituitary imaging with MRI showed in both patients the presence of a mass compatible with macroadenoma, that in the first patient showed characteristic of invasiveness. Both subjects underwent transphenoidal neurosurgery with the exeresis of the neoplasia, with resolution of the secondary hypogonadism and reappearance of the sexual potency. With the resume of sexual activity the patients complained the appearance of painful penis bending during erection. Dynamic echographic evaluation of the penis with 7.5 Mhz linear probe, after the intracavernous injection of prostaglandin E1 10 micrograms, showed in both patients the presence of a hyperechogenic plaque in the tunica albuginea compatible with IPP. Both patients underwent successfully surgery for the excision of the plaque and the apposition of a patch of dura mater. The authors want to underlie as the onset of IPP can be sudden, promoted by the resolution of the hypogonadism secondary to pituitary neoplasia, and contemporary to the normalization of testosterone levels.

Adenoma↗

PubMed1995

Relationship between the presence of endogenous nicks and sperm chromatin packaging in maturing and fertilizing mouse spermatozoa.

Mammalian spermiogenesis involves the replacement of histones by protamines, resulting in a highly compacted chromatin. Upon fertilization, the reverse process occurs. We have previously shown that the chromomycin A3 (CMA3) fluorochrome represents a useful tool for detecting protamine deficiency in spermatozoa. In this study we investigated CMA3 fluorochrome accessibility and the presence of endogenous nicks in maturing and fertilizing mouse sperm. Testicular sperm of stages 1-7 and 8-14 showed high positivity (> 96%) to CMA3, decreasing to 63% in stage 15-16 spermatids. In situ protamination of stage 15-16 spermatids saw an inhibition of CMA3 accessibility. Only 8% of the mature spermatozoa in the efferent ducts were CMA3-positive; this value decreased to 0% in the caput epididymidis. At fertilization, CMA, fluorescence reappears in decondensing sperm. Fluorescein isothiocyanate (FITC) fluorescence, identifying endogenous nicks, was evident in 6% of stage 1-7 spermatids, increased to 22% in stage 8-14 spermatids, and disappeared in stage 15-16 spermatids. During fertilization, endogenous nicks were not observed in decondensing sperm. We propose that 1) the presence of nicks in mouse testicular spermatids suggests that DNA cutting and ligating occurs prior to completion of protamination and 2) the absence of nicks during fertilization indicates that decondensation is not simply the reversal of the initial chromatin packaging process.

Animals↗

PubMed1995

Non-typhoid Salmonella subdural empyema in a patient with AIDS.

In AIDS patients, non-typhoid salmonella metastatic abscesses in lung and brain due to bacteremia have been described previously. Here we present a case in which a group B Salmonella, serotype Copenhagen, caused right parietal subdural empyema. The etiologic diagnosis was based on culture of pus obtained from the lesion. The patient was treated for bacterial meningitis and made a good recovery. He is at present reasonably well and is taking ciprofloxacin as prophylaxis against salmonella relapse.

AIDS-Related Opportunistic Infections↗

PubMed1992

Plasmid analysis in PPNG strains isolated in Italy.

Italian reports of PPNG strains are rare. In this paper we report the plasmidial characteristics of two strains: one harbouring 3.2 and 2.6 Mdal plasmids and the other 24.5, 4.5 and 2.6 Mdal plasmids. Restriction analysis was carried out on plasmids transferred to E. coli by transformation for "Africa" and conjugation for "Asia" plasmid.

DNA, Bacterial↗

PubMed1991

Streptococcus mutans: classification in bacteriocin-types.

A sample of S. mutans bacteriocins was studied to obtain a useful outline of strain typing since their synthesis has proved stable and not under plasmidial control. The inhibiting effectiveness against 9 oral streptococci and the sensitivity of mutacins produced by 49 S. mutans strains to heat, chloroform and proteasic activity were evaluated. On the basis of our results the producing strains are classified into five different types. We examine the possibility of obtaining a useful typing with bacteriocins and we discuss the choice of the most suitable number of indicators to arrange the strains in a limited cluster number for epidemiological purpose, or to classify freshly isolated S. mutans strains into bacteriocin-types.

Bacterial Typing Techniques↗

PubMed1987

In vitro antibacterial activity of enoxacin, a new pyridonecarboxylic acid.

The antibacterial activity of enoxacin was determined against 1015 strains of Gram-positive and Gram-negative bacteria, mainly freshly isolated from clinical specimens. The minimum inhibitory concentrations (MIC 50-75-90) were determined in comparison to three commonly used antibiotics: ampicillin, cefotaxime and gentamicin. Enoxacin has shown a broad spectrum of action and antibacterial activity in general higher that than of three currently available antibiotics. The antibacterial activity seems similar to that of other quinolones of second generation.

Ampicillin↗