Monica Giammarioli

Antimicrobial susceptibility of potentially pathogenic halophilic vibrios isolated from seafood

Susceptibility patterns to 27 antimicrobial agents and beta-lactamase production were investigated in potentially pathogenic halophilic vibrios from seafood. The effect of salinity on the response to the drugs in vitro was also studied. All isolates were uniformly sensitive to choramphenicol, imipenem, meropenem but resistant to lincomycin. All were highly sensitive to oxolinic acid, trimethoprim-sulphamethoxazole, doxycycline, flumequine, cefotaxime, nalidixic acid and ciprofloxacin. Some strains of V. harveyi, V. alginolyticus and V. parahaemolyticus apparently had mechanisms of resistance to several beta-lactam antibiotics other than by the production of beta-lactamases. Sixty-nine strains produced penicillinase but a low correlation between beta-lactamase activity and resistance to beta-lactam antibiotics was noted. The salt concentration affected the in vitro susceptibility of halophilic vibrios and the effect of salinity depended on both the individual strains and the antimicrobial tested.

Early Induction of Interleukin-12 by Human Monocytes Exposed to Cryptococcus neoformans Mannoproteins

ABSTRACT Interleukin-12 (IL-12) production by human monocytes stimulated with mannoproteins (MPs) of Cryptococcus neoformans was investigated. The results reported show that secreted or cell-associated MPs induce an early and significant production of IL-12. MPs show different capabilities to quantitatively affect IL-12 production; MP2, an 8.2-kDa MP purified from the culture supernatant ofC. neoformans, appears to be the most potent stimulator. Cytochalasin B inhibits both internalization and IL-12 induction by MP. In addition, a drastic reduction of IL-12 was observed when monocytes were cultured in the absence of normal human serum or treated with soluble mannan. Early production of IL-12 promotes early secretion of gamma interferon by T cells but does not influence the magnitude of the MP-induced lymphoproliferative response. Overall our results identify cryptococcal antigens responsible for rapid and potent induction of IL-12 in monocytes. MPs appear to regulate IL-12 secretion by internalization via the endocytic pathway and by interaction with monocyte receptors or serum factors.

Apert's syndrome: differential in vitro production of matrix macromolecules and its regulation by interleukins

During embryonic development, variations in the composition of the extracellular matrix (ECM) macromolecules influence bone tissue differentiation. We present novel findings on the in vitro phenotypic expression of periosteal fibroblasts obtained from patients affected by Apert’s syndrome, a rare craniofacial malformation, and the effects that interleukins (ILs) induce on the phenotype. Apert fibroblasts synthesized greater quantities of glycosaminoglycans (GAGs) and intracellular type I collagen, and also produced more type III collagen and fibronectin. The amount of hyaluronic acid (HA) secreted by Apert fibroblasts was much higher than that secreted by normal fibroblasts, but, as the absolute values of heparan sulphate (HS), chondroitin sulphate (CS) and dermatan sulphate (DS) also rose in Apert media, the HA–sulphated GAG ratio was similar in the media obtained from both populations. Both ILs triggered elevations of HA in normal cells, although relative percentage secretion remained unaltered, but significantly reduced HA secretion by Apert cells. IL‐1 significantly increased CS in normal and Apert media, whereas IL‐6 enhanced HS and DS in media of both populations. HA–sulphated GAG ratio decreased in Apert media after IL treatment. Both ILs boosted fibronectin production by Apert fibroblasts, whereas IL‐1 increased type III but not type I collagen. Taken together, these data demonstrate that the synthesis and secretion of ECM macromolecules are markedly altered in Apert fibroblasts. The fact that treatment with ILs further modifies the Apert phenotype suggests that ILs may be implicated in the pathophysiology of the malformations during skull morphogenesis.

Glycosaminoglycan Metabolism and Cytokine Release in Normal and Otosclerotic Human Bone Cells Interleukin-1 Treated

Glycosaminoglycans (GAGs), normal components of the extracellular matrix (ECM), and the glycosidases, that degrade them, play a key role in the bone remodelling process. The effects of interleukin-1 alpha (IL-1 alpha) on GAG metabolism in normal and otosclerotic human bone cells as well as its capacity to modulate IL-1 alpha, IL-1 beta and IL-6 secretion in both populations was analyzed. The amount of radiolabeled GAGs was lower in otosclerotic than in normal bone cells. IL-1 alpha reduced newly synthesized cellular and extracellular GAGs in normal cells, but only those of the cellular compartment in otosclerotic bone cells. It depressed heparan sulphate (HS) more in normal cells and chondroitin sulphate (CS) more in otosclerotic bone cells. The HA/total sulphated GAG ratio was shifted in favour of the latter in otosclerotic cells, whereas the opposite effect was seen after IL-1 alpha treatment. There was little difference in the beta-D-glucuronidase levels of the normal and pathological cells, while beta-N-acetyl-D-glucosaminidase was significantly increased in otosclerotic bone cells. As the activity of neither enzyme was modified by treatment with IL-1 alpha, the cytokine seems to exert its influences on GAG synthesis rather than on the degradation process. IL-1 alpha, IL-1 beta and IL-6 secretion was markedly higher in otosclerotic cells. IL-1 alpha modulated the secretion of each interleukin differently, thus resulting in a cytokine cascade that may act in autocrine/paracrine manner on target cells. The authors suggest that changes in the cytokine network may have a specific, yet still unknown, role during normal and pathological osteogenesis.

Interleukin pattern of Apert fibroblasts in vitro.

The phenotype of cultured fibroblasts from patients affected by Aperts syndrome, a rare connective disorder, differs from that of normal cells in its extracellular matrix macromolecule composition (glycosaminoglycans, collagens and fibronectin) and is further modulated by treatment with interleukins (ILs). As the mechanisms responsible for the changes are unknown, we used our recently described model system for Apert periosteal fibroblasts to ascertain whether the pattern of ILs they secrete into the medium is comparable to that of normal fibroblasts. The results obtained by enzyme-linked immunosorbent assay (ELISA) show that the levels of interleukin-1 (IL-1) and interleukin-6 (IL-6) were lower in Apert than in normal media, whereas levels of IL-1 receptor antagonist (IL-1ra), the natural inhibitor of IL-1, were markedly higher. IL-1 specific bio-activity on thymocyte proliferation was also decreased in Apert supernatants. As we provided also evidence that active transforming growth factor beta (TGFbeta1), an IL-1 antagonist, was not secreted in greater amount in Apert media with respect to normals, the enhancement of IL-1ra appeared critical in down-regulating IL-1. Northern blot analysis of cytokine mRNA revealed no detectable IL-1 or IL-6 gene expression in normal fibroblasts, but high amounts of IL-6 mRNA transcripts in Apert cells. As the increased IL-6 gene expression did not translate into a parallel increase of secreted IL-6, the control of IL-6 secretion may be mainly post-transcriptional. Furthermore, the result that a treatment of the cultures with IL-1ra was able to induce a decrease of IL-6 secretion, suggests that the observed decreased secretion of IL-6 may be due to the autocrine action of overproduction of IL-1ra. The observed imbalance in the production of ILs which we show for the first time suggests ILs may be the natural autocrine regulators of ECM production in Apert fibroblasts. We hypothesize that in vitro differences previously reported in fibroblast phenotypes and several clinical features of Aperts syndrome may correlate with different cytokine patterns.

Microbial environmental monitoring of the refectory in the monastery of St. Anna in Foligno, Italy

For the preservation of monuments and sites of cultural heritage, microbiological methods based on defined standards are needed to evaluate the problems associated with biodeterioration. In this study Microbial Environmental Monitoring (MAM from the Italian acronym Monitoraggio Ambientale Microbico) was applied to air and surface monitoring of art works before and during restoration. Microbial monitoring of the refectory in the monastery of St. Anna (Foligno, Italy) was performed on frescos from 1400. The results obtained with MAM were consistent, reproducible, and beneficial in the evaluation of the efficacy of restoration. Microbial monitoring of solid surfaces using membrane filters was not destructive and allowed the study of microbial fall-out on the surface of art works. The application of MAM proved to be a valuable means not only for monitoring but also for a better understanding of microbial pollution and its dynamics on the surface of art works. The constant application of MAM could be a valuable tool in the preservation of cultural heritage through strict collaboration with microbiologists, restorers, and authorities.

Correlation between medium acidification and pathogenicity in environmental halophilic non‐cholera vibrios

Aims: The metabolic characterization and pathogenicity of vibrios isolated from seafood were studied.

Glycosaminoglycan profile in macrophages exposed to Candida albicans and interleukins.

Glycosaminoglycans (GAG), are extracellular matrix macromolecules that affect the phagocytic properties of macrophages. In order to assess whether the interaction between macrophages and Candida albicans (iCa) provokes changes in the phenotype, we analyzed the GAG profiles in two macrophage lines, ANA‐1 (from murine bone‐marrow) and BV‐2 (from murine brain). We also investigated GAG modulation by interleukin‐1α (IL‐1α) and interleukin‐6 (IL‐6). During iCa treatment and even after the addition of ILs, ANA‐1 accumulated less total GAG compared to controls. IL‐1 treatment, combined with iCa exposure, induced a decrease in heparan sulfate and chondroitin sulfate chains, and an increase in the hyaluronic acid percentage. IL‐6 treatment, with or without iCa, decreased the hyaluronic acid/sulfated GAG ratio. The GAG pattern in BV‐2 appears to be different to ANA‐1 and iCa exposure does not induce any difference in total GAG. The inhibitory effect induced by ILs on GAG synthesis is less than that observed in ANA‐1 and the GAG elution profile is modulated to a lesser extent by treatment with ILs and/or iCa compared to the ANA‐1. We suggest that the observed changes in the expression of the individual GAG classes may be responsible for the macrophage functional heterogeneity. J. Leukoc. Biol. 64: 650–656; 1998.

COLLAGEN SYNTHESIS AND CELL GROWTH IN CHICK EMBRYO FIBROBLASTS: INFLUENCE OF COLCHICINE, CYTOCHALASIN B AND CONCANAVALIN A

Culturing of chick embryo fibroblasts in the presence of colchicine or cytochalasin B with and without concanavalin A (Con A) demonstrated that colchicine induces greater neosynthesis of endocellular type I collagen, whereas cytochalasin B boosts secretion. The effects are modified by the addition of Con A, which increases α2more than a1 chain production.3H‐thymidine incorporation is unaffected by cytochalasin B, but stimulated by colchicine. Con A neutralizes the stimulatory action of colchicine. It would therefore seem that Con A exerts transmembrane control of effects induced by colchicine and cytochalasin B by binding to cell surface receptors and so triggering rearrangement of the cytoskeleton.

Cell uptake and DNA adduct formation of the 2-amino-3 methyl-imidazo (4,5-f) quinoline in human enterocytes and chick embryo liver cells

The compound 2-amino-3-methyl-imidazo(4,5-f)quinoline (IQ) is a powerful mutagenic compound that can induce tumours in different rat and murine target organs (liver, forestomach and small and large bowel). The ability of mutagenic IQ to form adducts to human embryonic enterocyte DNA (intestine 407 cell lines ATCC) has been studied, considering the DNA extracted from the cells and DNA of the in vitro-cultured cells. The activation with the rat hepatic microsomial fraction S9 plays an important role not only in DNA binding, but also in the uptake of IQ by the enterocytes. In the presence of S9 mix, the DNA adduct formation increases with the incubation time; in the absence of metabolic activation, the binding does not occur. Parallel experiments were carried out for comparison on chick embryo hepatocytes; for these cells, the metabolic activation with S9 mix is not as critical as for enterocytes in IQ uptake and DNA binding.