Lysozyme affects the microbial catabolism of free arginine in raw-milk hard cheeses.

Lysozyme (LZ) is used in several cheese varieties to prevent late blowing which results from fermentation of lactate by Clostridium tyrobutyricum. Side effects of LZ on lactic acid bacteria population and free amino acid pattern were studied in 16 raw-milk hard cheeses produced in eight parallel cheese makings conducted at four different dairies using the same milk with (LZ+) or without (LZ-) addition of LZ. The LZ-cheeses were characterized by higher numbers of cultivable microbial population and lower amount of DNA arising from lysed bacterial cells with respect to LZ + cheeses. At both 9 and 16 months of ripening, Lactobacillus delbrueckii and Lactobacillus fermentum proved to be the species mostly affected by LZ. The total content of free amino acids indicated the proteolysis extent to be characteristic of the dairy, regardless to the presence of LZ. In contrast, the relative patterns showed the microbial degradation of arginine to be promoted in LZ + cheeses. The data demonstrated that the arginine-deiminase pathway was only partially adopted since citrulline represented the main product and only trace levels of ornithine were found. Differences in arginine degradation were considered for starter and non-starter lactic acid bacteria, at different cheese ripening stages.

cDNA-amplified fragment length polymorphism to study the transcriptional responses of Lactobacillus rhamnosus growing in cheese-like medium.

AIMS: Lactobacillus rhamnosus is a dominant species during Parmigiano Reggiano cheese ripening and exhibits a great adaptability to unfavourable growth conditions. Gene expression of a Lact. rhamnosus, isolated from Parmigiano Reggiano cheese, grown in a rich medium (MRS) and in a cheese-like medium (CB) has been compared by a novel cDNA-amplified fragment length polymorphism (cDNA-AFLP) protocol. METHODS AND RESULTS: Two techniques, capillary and gel electrophoresis cDNA-AFLP, were applied to generate unique transcript tags from reverse-transcribed messenger RNA using the immobilization of biotinylated 3'-terminal cDNA fragments on streptavidin-coated Dynabeads. The use of three pairs of primers allowed detecting 64 genes expressed in MRS and 96 in CB. Different transcripts were observed when Lact. rhamnosus was cultured on CB and MRS. CONCLUSIONS: The cDNA-AFLP approach proved to be able to show that Lact. rhamnosus modifies the expression of a large part of genes when cultivated in CB compared with growth under optimal conditions (MRS). In particular, the profiles of the strain grown in CB were more complex probably because the cells activate different metabolic pathways to generate energy and to respond to the environmental changes. SIGNIFICANCE AND IMPACT OF STUDY: This is the first research on Lact. rhamnosus isolated from cheese and represents one of the few concerning bacterial transcriptomic analysis towards cDNA-AFLP approaches.

Natural whey starter for Parmigiano Reggiano: culture-independent approach.

AIMS: The aim of this work was to obtain a deeper insight into the knowledge of microbial composition of Parmigiano Reggiano natural whey starters through different culture-independent methods. METHODS AND RESULTS: Eighteen different Parmigiano Reggiano natural whey starters sampled from three different provinces of this cheese production area and the nonacidified wheys from which they arose have been studied by length heterogeneity polymerase chain reaction (LH-PCR) and fluorescent in situ hybridization (FISH). A high microbial composition variability between different samples has been observed. CONCLUSIONS: Revealing different images of the same community, LH-PCR and FISH have given a more accurate view of the not well-known Parmigiano Reggiano whey starter ecosystem. SIGNIFICANCE AND IMPACT OF THE STUDY: New lights have been shed on Parmigiano Reggiano natural whey starters microbial composition, highlighting how culture-independent approach could be used and improved to study this and other food ecosystems.

Nickel(II) 2,6-diacetylpyridine bis(isonicotinoylhydrazonate) and bis(benzoylhydrazonate) complexes: structure and antimycobacterial evaluation. Part XI.

The reaction of 2,6-diacetylpyridine (dap) and isonicotinoyl- or benzoylhydrazide leads to bishydrazones H(2)dapin (1a) and H(2)dapb (1b), respectively. The condensation can either take place as a bimolecular kinetic process between the two reactants or as a monomolecular metal-templated synthesis in the presence of nickel(II) ions. In the latter case the reaction products are charged 2,6-diacetylpyridine bis(hydrazone) nickel(II) complexes, which can be easily deprotonated to neutral hydrazonates. Diffractometric analysis of one of these [Ni(dapb)](2) (8b) has shown a binuclear structure with two octahedral nickel(II) ions bridged by two helicoidal dap (bishydrazonates) in a spheroidal structure of C(2V) symmetry. The synthesized complexes 8 are promising as antimycobacterial agents against M. tuberculosis H37Rv. In particular, 8b displays significant activity (MIC=0.025 microg/mL) 10-fold higher than rifampin and equal to isoniazid, while its ligand is ineffective. Compound 8b is also capable of reducing HIV-induced cytopathogenic effect in human T(4 )lymphocytes.

Antimycobacterial in vitro activity of cobalt(II) isonicotinoylhydrazone complexes. Part 10.

Octahedral cobalt(II) complexes of isonicotinoylhydrazones, which were obtained from the primary antituberculous agent isoniazid, have been synthesised and characterised. Their antimycobacterial in vitro activity has been evaluated against Mycobacterium tuberculosis H37Rv: they exhibit MIC values ranging from < 0.1 to 0.39 microg/mL, showing them to be generally more active than previously reported analogous Cu(II) and Ni(II) complexes.

Isoniazid-related copper(II) and nickel(II) complexes with antimycobacterial in vitro activity. Part 9.

Isonicotinoylhydrazones 1, obtained by the primary antituberculous agent Isoniazid, have been used as monoanionic ligands (L) to prepare copper(II) 2 and nickel(II) 3 octahedral complexes of stoichiometry [MeL2(H2O)2]. Their antimycobacterial in vitro activity was evaluated against Mycobacterium tuberculosis H37Rv in comparison with the ligands. Complexes 2a, 2b, 2f, 3b, 3d and 3g displayed MIC values < or = 0.2 microg/mL.

High-dose aprotinin with gentamicin-vancomycin antibiotic prophylaxis increases blood concentrations of creatinine and cystatin C in patients undergoing coronary artery bypass grafting.

Both aprotinin and gentamicin-vancomycin antibiotic prophylaxis have been used widely in cardiac surgery to prevent bleeding and infections, respectively. As the drugs are excreted almost entirely by glomerular filtration, we investigated their action on renal function when administered either separately or together. To increase consistency, we measured serum concentrations of creatinine and cystatin C, a new marker of glomerular filtration rate, that many recent studies have shown to be more sensitive than serum creatinine. One hundred patients undergoing coronary artery bypass surgery were allocated randomly to one of four groups: group A received antibiotic prophylaxis with cefamandole and no aprotinin; group B received cefamandole and high-dose aprotinin; group C received antibiotic prophylaxis with gentamicin and vancomycin, but no aprotinin; and group D received both high-dose aprotinin and gentamicin-vancomycin antibiotic prophylaxis. Data from 84 patients, for whom data collection was complete, were analysed. In the first week after operation, mean serum concentrations of cystatin C and creatinine either remained constant or decreased slowly in all groups, except for group D. In group D, both markers increased gradually from postoperative day 2 onwards. The increase in cystatin C was significant on postoperative day 5 (from mean 1.02 (SD 0.11) mg litre-1 before operation to 1.35 (0.32) mg litre-1; P < 0.05), reaching a peak on postoperative day 7 (1.45 (0.35) mg litre-1; P < 0.05), while the increase in creatinine concentration was significant on postoperative day 6 (from 1.05 (0.16) mg dl-1 before operation to 1.29 (0.34) mg dl-1; P < 0.05). We conclude that simultaneous administration of high-dose aprotinin and prophylactic use of gentamicin with vancomycin increased serum concentrations of cystatin C and creatinine in the first postoperative week in patients undergoing cardiac surgery.

Calcium chloride minimizes the hemodynamic effects of propofol in patients undergoing coronary artery bypass grafting.

OBJECTIVE: To assess the hemodynamic effects of propofol and the counteracting effect of calcium chloride (CaCl2) in patients undergoing coronary artery bypass grafting (CABG). DESIGN: Prospective, randomized study. SETTING: University hospital, department of cardiac surgery. PARTICIPANTS: Fifty-eight patients undergoing elective CABG, divided into group A (n = 29) and group B (n = 29). INTERVENTIONS: Anesthesia was induced with a combination of fentanyl, 7 microg/kg; pancuronium, 0.1 mg/kg; and propofol, 1.5 mg/kg, administered over 60 seconds. A blinded investigator administered saline in group A patients and 10 mg/kg of CaCl2 in group B patients at the same speed and same time as propofol administration through another lumen of the central venous catheter. MEASUREMENTS AND MAIN RESULTS: Hemodynamic data were obtained at baseline (T0), 2 minutes after anesthesia induction (T1), and 2 minutes after tracheal intubation (T2). Heart rate decreased significantly in group A patients (86.2+/-11.3 beats/min at T0 and 72.8+/-7.5 beats/min at T2; p < 0.001). Mean arterial pressure decreased significantly in patients in both groups (group A, 108.0+/-12.0 mmHg at T0; 74.6+/-14.6mmHg at T2;p < 0.001 and group B, 106.0+/-10.2 mmHg at T0; 90.4+/-10.0 mmHg at T2; p < 0.05). Stroke volume index, cardiac index, and cardiac output decreased in group A patients (39.4+/-4.1 mL/beat/m2 at T0 and 28.8+/-5.2 mL/beat/m2 at T2; p < 0.05; 3.4+/-0.6 L/min/m2 at T0 and 1.9+/-0.3 L/min/m2 at T2; p < 0.001; 5.9+/-0.9 L/min at T0 and 3.4+/-0.4 L/min at T2; p < 0.001, respectively), whereas in group B patients, changes were negligible (38.1+/-7.0 mL/beat/m2 at T0 v 35.7+/-6.6 mL/beat/m2 at T2; (NS) 3.3+/-0.5 L/min/m2 at T0 v 2.7+/-0.3 L/min/m2 at T2; (NS) 5.7+/-0.9 L/min at T0 v 4.7+/-0.5 L/min at T2; (NS), respectively). CONCLUSION: Simultaneous administration of CaCl2 during the induction of anesthesia minimizes the potential negative effect of propofol on cardiac function in cardiac patients.