Search Results

You are looking at 1 - 10 of 40 items for :

  • "bacterium" x
  • Materials and Applied Sciences x
  • Architecture and Architectonics x
  • All content x
Clear All

bacterium Alicyclobacillus acidocaldarius: Identification of the active site residues . Biochim. Biophys. Acta , 1784 , 292 – 301 . L OWRY , O.H. , R OSEBROUGH , N.J. , F ARR , A

Restricted access

Abstract

The probiotic and technological potentials of lactic acid bacteria originating from human milk are becoming a remarkable research area. In the present study, Limosilactobacillus vaginalis MA-10 isolated from human milk was investigated in vitro for its probiotic and technological aspects. According to the results obtained in the study, MA-10 strain exhibited non-haemolytic activity and various degrees of sensitivity to most of the tested antibiotics. The strain showed good resistance to the gastrointestinal system and maintained its viability under these conditions. Its antimicrobial activity against human or clinical bacterial and fungal microorganisms and fish bacteria was determined in the range of 2.38–11.22 mm. The MA-10 strain was able to assimilate cholesterol ranging from 31.42 to 82.30%. The strain showed 9.34% ferrous-ion chelating and 32% DPPH free radical scavenging activities. These initial results from the present study confirm that L. vaginalis MA-10 may be a new source with appropriated probiotic and technological traits for various industries, and further in vivo assays.Due to the limited number of studies on L. vaginalis strains originated from human breast milk in the literature, the data obtained in this study are thought to be important for revealing the basic probiotic properties of the strain.

Open access

Abstract

There are numerous biological agents including bacteria such as Brucella suis, B. abortus, Francisella tularensis, Burkholderia mallei, Coxiella burnetii, Yersina pestis, Bacillus anthracis and Chlamydia psittaci, viruses such as Variola major and V. minor, Flavivirus and Hantavirus, and toxins such as Botulinum toxin produced by the bacterium Clostridium botulinum, Staphylococcus enterotoxin B and Trichothecene mycotoxin reported to have potential to cause illness via water consumption. In the recent years, biological threat prevention for urban water supply systems has been of special interest worldwide, thus, protection against biological agents requires adequate knowledge, available water treatment technologies and preparedness. In this review, the history of biological threat via public water supply, as well as selected early detection methods, prevention strategies and risk assessment models are detailed.

Restricted access
Acta Alimentaria
Authors: N. Topic Popovic, A. Benussi Skukan, P. Dzidara, I. Strunjak-Perovic, S. Kepec, J. Barisic, and R. Coz-Rakovac

.B.R. ( 1926 ): A disease of rabbits characterized by a large mononuclear leucocytosis, caused by a hitherto undescribed bacillus Bacterium monocytogenes (n.sp.) . J. Pathol.Bacteriol ., 29 , 407 – 439

Restricted access

is little information on the use of starter cultures in the previous reports on bread making from composite flour. Therefore, this study was aimed at using lactic acid bacterium and yeast associated with fermenting cassava, sweet potato, and soybean

Restricted access
Acta Alimentaria
Authors: K. Régaiszné Vajda, A.A. Halbritter, P. Szűcs, J. Szigeti, and B. Ásványi

Sous-vide (French for ʽunder vacuum’) is a professional cooking method, by which, under oxygen-free conditions and precise temperature control, not only cooking but preservation is achieved. During the process the food matrix is vacuum-packed and undergoes a mild heat treatment, thus achieving an enhanced nutrition value and a better organoleptic character. Due to the mild heat treatment (55 to 90 °C), the high water activity, and the slight acidity of raw materials, the microbial quality assurance is a great challenge even for professionals. The heat treatment does not assure the inactivation of pathogen spores. In our experiments we used Clostridium perfringens representing the spore-forming pathogens, and Salmonella Enteritidis as a the food-borne infection bacterium. Effects of various temperatures were measured in normal and sous-vide type vacuum packaging. Higher thermal death rate in vacuum packaging was demonstrated for Salmonella Enteritidis and Clostridium perfringens.

Restricted access

Examination of heat shock and PR (“pathogenesis-related”) proteins is of special interest in food science. Many food allergens have a similar or the same structure as PR proteins, which are produced in the plants as a response to pathogenesis or certain environmental stresses. The protein set of the psychrophilic bacterium Shewanella hanedai was studied by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Gel patterns from control and heat-treated bacteria were evaluated by PDQUEST software. The differentially expressed proteins were excised from the gel and digested by trypsin. The tryptic peptides were analysed by nanoflow LC-MS/MS. On the basis of amino acid sequences obtained by this method, the proteins were identified by similarity searching in the protein database. Using this proteomic approach a heat shock and a 50S ribosomal protein were identified as the major heat induced proteins in Shewanella hanedai.

Restricted access

In this study, the antibacterial and antioxidant activities of dried fruit extract of cranberry (gilaburu, Viburnum opulus) were determined. The total phenolic content was found to be 131.99±2.11 mg gallic acid equivalent (GAE) g-1 in the cranberry fruit extract (CFE). The antioxidant activity of the extract was found to be 315.50±8.2 mg g-1 in dried methanol extract. At 2, 5, 10 and 15% concentrations the extracts were tested for their antibacterial effects by using the agar diffusion method against ten bacteria, some of them pathogenic and some of them spoilage microorganisms. All bacteria were inhibited by 10 and 15% concentrations of the CFE. Methanol (control) had no inhibitory effect on all the tested bacteria. The most sensitive of the bacteria was A. hydrophila, whereas the most resistant bacterium was Y. enterocolitica.

Restricted access

In this study, detection of an obligate aerobic, thermophilic and acidophilic bacterium, the sporeforming Alicyclobacillus acidoterrestris was performed by determination of its specifc metabolite, guaiacol. Since its spores have been shown to resist conventional pasteurization, it has become a potential spoilage concern for fruit and vegetable juices, mainly for apple and orange juices. Detection of guaiacol was carried out by using an NST 3320 type electronic nose, and other methods, such as peroxidase-based enzymatic method with UV-Vis spectrophotometer, SPME-GC-MS technique and an untrained sensory panel were also applied. The results indicated that based on their detection limit the methods can be ordered in the following way: SPME-GC-MS (detection limit: <0.5 ppm)<sensory evaluation (detection limit: 0.5–1 ppm)<spectrophotometric method=electronic nose technique (detection limit: 1.25–2.5 ppm).

Restricted access
Acta Alimentaria
Authors: J. A. Grahovac, Z. Z. Rončević, I. Ž. Tadijan, A. I. Jokić, and J. M. Dodić

Bacillus subtilis is one of the most important producers of diverse antimicrobial compounds. This bacterium grows and produces antibiotics on different substrates. The increase of the antibiotics yield can be achieved by changing the conditions of cultivation and the composition of the culture media. In this study, response surface methodology was used for optimization of glycerol, sodium nitrite, and phosphate content in media for production of antibiotics effective against Staphylococcus aureus. As biosynthesis strain Bacillus subtilis ATCC 6633 was used. The developed model predicts that the maximum inhibition zone radius (38.08 mm) against Staphylococcus aureus and minimal amount of residual nutrients (glycerol 1.75 g l−1, nitrogen 0.21 g l−1, phosphorus 0.18 g l−1) are achieved, when the initial content of glycerol, sodium nitrite, and phosphate are 49.99 g l−1, 1.00 g l−1, and 5.00 g l−1, respectively.

Restricted access