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Acta Alimentaria
Authors:
M. Szalai
,
J. Szigeti
,
L. Farkas
,
L. Varga
,
A. Réti
, and
E. Zukál

The shelf-lives of major commercial cooked meat products (i.e., Bologna sausage, Italian-type cooked sausage, and cooked ham) packaged under vacuum or modified atmospheres were tested in this study. Samples were taken from commercial meat processing lines, sliced to 1.2 mm thickness and placed overlapped into polypropylene trays sealed with plastic films. The headspace of modified atmosphere packaged formulations consisted of 30% CO2 and 70% N2 or 60% CO2 and 40% N2. The samples thus produced were stored under refrigerated conditions. The values of microbiological, chemical, physical or sensory properties were plotted against storage time, and Gompertz curves were fitted to all time series that changed from an initial to a final value during any period of storage. The influence of headspace CO2 concentration on the properties of sliced cooked meat products varied considerably and, therefore, it was not possible to specify general rules. However, the presence of CO2 in the packaging atmosphere slowed down the rate of microbial growth, thereby delaying the spoilage of meat products. A CO2 level of 60% had beneficial effects on both the microbiological and sensory properties of sliced sausages and cooked ham. It was concluded that cooked meat products packaged under modified atmospheres had a shelf-life of 20 days.

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The aim of the present study was to identify gene expression changes in the rapid cardiac pacing-induced delayed antiarrhythmic protection in the canine, using cDNA microarrays and quantitative real-time PCR (QRT -PCR) techniques. In all dogs under light pentobarbitone anaesthesia, a pacing electrode was introduced into the right ventricle, and then the animals were divided into three groups: (1) sham-operated and sham-paced group (SP, n = 3) (2) ischaemic control group (IC; n = 3); these were without cardiac pacing and subjected only to a 25 min occlusion of the left anterior descending coronary artery (LAD), and (3) paced group (PC, n = 3); these animals were paced at a rate of 220–240 beats min−1 24 h prior to ischaemia. With cDNA chip 23 genes were found with altered expression in response to rapid cardiac pacing and 10 genes in the IC group when compared to SP dogs. These genes encode transcription factors (MEF2); members of signaling pathways (TGFβ2, PDE4D9), hormone related proteins (e.g. vasopressin V1 and V2 receptors). RT-QPCR was used either to confirm the results of the microarray analysis and also to study 46 genes which are already known to have a role in the late phase of PC. By this method 17 genes were up-regulated and 6 genes down-regulated in the IC group; their expression ratios changed either to the opposite or showed no alteration after cardiac pacing. This study would add some new information about those transcriptional changes that are involved in the delayed phase of cardiac protection.

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Forest conversion to anthropogenic uses is a generalized phenomenon throughout tropical Latin America. We evaluated whether patches of secondary forest, which develop relatively rapidly after field abandonment, contribute to conservation of phyllostomid bat assemblages. Our objective was to compare patterns of phyllostomid bat abundance and the structure and composition of phyllostomid bat assemblages across three forest types in the northern neotropics of eastern Mexico. We studied phyllostomid bats within secondary evergreen, primary semi-deciduous, and primary evergreen forests. For each forest type, three representative sites were sampled with mist nets once during the dry season and once during the rainy season for a total of nine sites. Richness, diversity, and assemblage composition patterns were compared among forest types for all phyllostomid species, and for three groups of sensitivity to habitat fragmentation. Abundance of individual species was also compared among forest types. A total of 646 individual bats from 15 species, 11 of which were phyllostomids, were registered. Combining both seasons, more than 250 captures were accomplished at both the primary evergreen and secondary evergreen forests, and only 81 individuals were caught at primary semi-deciduous forests. Overall richness and diversity of species and sensitivity groups were greater in the rainy than the dry season. Richness was greater in secondary evergreen than in primary semi-deciduous forests, and diversity was greatest in the primary evergreen, intermediate in the secondary evergreen, and lowest in the primary semi-deciduous forest. Some overlap in composition was also evident, although there was separation between forest types and seasons. Mean abundances were higher for some species at primary evergreen and secondary evergreen forests, but were threefold lower (though not significantly) in secondary evergreen forests in the dry season for some other species. We also found that primary evergreen forests have the greatest importance for phyllostomids during the dry season. These results suggest that maintenance of secondary evergreen forests, which cover a large proportion of the northeastern Mexican neotropics, would contribute to the conservation of diverse tropical bat communities. Therefore, large areas of this forest type should necessarily be incorporated in the landscape.

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Abstract

The objective of this study was to use matrix-assisted laser desorption ionisation–time of flight mass spectrometry (MALDI-TOF MS) for the identification of ovine-associated staphylococci. Presumptive Staphylococcus isolates were recovered from ovine udder surface (US), individual raw milk, bulk tank milk, and cheese samples and were characterised by conventional phenotypic methods. A total of 69 bacterial isolates were further confirmed by MALDI-TOF MS. Forty-two (60.9%) of 69 isolates were successfully identified on genus and species level. Two thirds (n = 28) of the 42 identified isolates were shown to be Staphylococcus spp. These 28 staphylococcal isolates formed two clusters, one consisting of 22 Staphylococcus aureus strains and the other composed of 6 non-aureus staphylococci, including S. simulans (n = 3), S. auricularis, S. equorum, and S. haemolyticus. MALDI-TOF MS has proven to be a reliable tool for the identification of staphylococci from raw sheep's milk, especially bulk tank milk; however, currently it appears to be less useful for the identification of bacterial isolates originating from ovine US samples. This is the first study to evaluate the applicability of MALDI-TOF MS for identification of Staphylococcus spp. in ovine raw milk, cheese, and US samples in Hungary.

Open access
Acta Phytopathologica et Entomologica Hungarica
Authors:
A. Czelleng
,
Z. Bozsó
,
P. Ott
,
E. Besenyei
,
G. Varga
,
A. Szatmári
,
E. Szabó
,
L. Zsiros
, and
Z. Klement

Compared to the known method of conjugation the frequency of transposon mutagenesis following conjugation was enhanced 11-fold by two hours of pre-incubation of recipient Pseudomonas viridiflava 1 on conjugation media. The increased frequency was ƒ = 1.3 × 10 −4 . In other species of Pseudomonas, Pectobacteira and Xanthomonas high rates of transposon mutants were similarly obtained; however, in these strains the increased frequency was less than 5-fold.

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Acta Alimentaria
Authors:
J. Csapó
,
J. Schmidt
,
Zs. Csapó-Kiss
,
G. Holló
,
I. Holló
,
L. Wágner
,
É. Cenkvári
,
É. Varga-Visi
,
G. Pohn
, and
G. Andrássy-Baka

In the past years several methods have been developed for the determination of the proportion of the nitrogen-containing substances of microbial origin passed from the rumen into the abomasum or the small intestine. Recently, on examining the D-amino acid content of foodstuffs, particularly milk and milk products, it has been observed that, in addition to D-Ala, D- glutamic acid (D-Glu) and D-aspartic acid (D-Asp) can also be detected in similar quantities, primarily in products which have links with bacterial activity. This gave rise to the idea of examining the diaminopimelic acid (DAPA), D-Glu and D-Asp content of bacteria extracted from the rumen of cattle and that of chyme from the same cattle, in order to determine the type of relation existing among these three components, and to establish whether D-Asp and D-Glu can be used in the estimation of protein of bacterial origin. On determination of the DAPA, D-Asp and D-Glu content by means of amino acid analyser and high performance liquid chromatography of duodenal chyme from five growing bulls and of ruminal bacteria from the same bulls, the following values were established. For chyme (and, in brackets, for ruminal bacteria) r value calculated by means of linear regression was 0.78 (0.76) between DAPA and D-Asp, and 0.70 (0.81) between DAPA and D-Glu. The r values between the crude protein content of ruminal bacteria and the markers examined were found to be the following: DAPA, 0.74; D-Asp, 0.73; D- Glu, 0.61. In the model experiment performed for the re-obtaining of values for protein of bacterial origin the theoretical values were determined on the basis of D-Asp and D-Glu and values approximately 10% higher than the theoretical value on the basis of DAPA. It is therefore recommended that in addition to DAPA these other two amino acids be included among the bacterial protein markers.

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