Bacteria, micrococci

Mold-ripened cheeses are inoculated with mold spores which germinate and, via metabolic transformation, produce additional characteristic flavor compounds. Blue-vein cheeses are good examples. In these cheeses, surface molds, yeasts, and bacteria (micrococci) become dominant as the cheese pH drops due to the lactic flora early in maturation. The main... 

Prepare a known inducer for the immune response of invertebrates (see Note 4). An efficient inducer is a cocktail of overnight cultures of a Gram-positive bacteria (Micrococcus luteus) and a Gram-negative bacteria (wild-type Escherichia coli). 

Twenty years later Dworkin [26] demonstrated that a flare of M. xanthus moved towards clumps of potential prey bacteria Micrococcus luteus). However, the same response was obtained with polystyrene latex beads or glass beads, ruling out the possibility that the cells were responding to a concentration gradient of some chemoattractant. Indeed, Dworkin and Eide [29] failed to detect any chemotactic response when various chemicals were examined as potential attractants... 

Gram positive bacteria Micrococcus flavus (Product isolate) 25.0... 

Carbamate hydrolysis is frequendy observed as the initial reaction for pesticides having carbamate bonds, such as aldicarb, carbofuran, carbaryl, and benomyl (eq. 12) (19). Numerous genera of carbamate-hydroly2ing bacteria have been identified, including Pseudomonas, Jhihrobacter, Bacillus, Nocardia, Achromobacter, Flavobacterium, Streptomyces, Alcaligenes, A spirillum, Micrococcus, and Bhodococcus. 

Figure 4.9 Images of Micrococcus lyiae bacteria inactivation of the photocatalyst,...

The decrease of peak numbers was observed, when the spectra of the same amounts of fresh (12 weeks old) and aged (9 months old) mortars were compared. This decrease might be caused by activity of ubiquitous microorganisms that live on the mortar surfaces in biofilms. Especially in mild climate conditions, algae and cyanobacteria [35] can appear here moulds (Aspergillus, Penicillium, Fusarium, Mucor) [36] and bacteria (Arthrobacter Bacillus, Micrococcus, Staphylococcus) [37,38] have been discovered as well. The microorganisms secrete various hydrolytic enzymes that can decompose the organic additives, namely proteins, and make their sample identification less sensitive... 

Indeed, these results are qualitatively similar to those depicted in Figs. 12 and 13, and it is therefore tempting to ascribe them to the presence, on the bacterial cell walk, of polyanionic environments surrounding the sites where lysozyme cleaves the polysaccharide network. However, the point is that, although several authors have concluded from various experimental observations that the cell walls of bacteria such as Escherichia coli and Micrococcus luteus are predominantly negatively charged (Katerakky et al, 1953 Salton, 1964 Davies et al, 1969), the complexity of the bacterial cell wall architecture means that little is known about the... 

Within the operationally defined marine bacteria , i.e., bacteria isolated from marine samples on marine media, bioactive compounds have been reported from Pseudoalteromonas, Cytophaga, Alteromonas, Micrococcus, Bacillus, Acinetobacter, Agrobacterium and Pseudomonas or from unidentified bacteria (Fig. 2). 

Properly made cheese is quite a hostile environment for bacteria due to a low pH, moderate-to-high salt in the moisture phase, anaerobic conditions (except at the surface), lack of a fermentable carbohydrate and the production of bacteriocins by the starter. Consequently, cheese is a very selective environment and its internal non-starter microflora is dominated by lactic acid bacteria, especially mesophilic lactobacilli, and perhaps some Micrococcus and Pediococcus. 

In surface smear-ripened cheeses, e.g. Munster, Limburger, Tilsit, Trapist, the surface of the cheese is colonized first by yeasts which catabolize lactic acid, causing the pH to increase, and then by Brevibacterium linens, the characteristic micro-organism of the surface smear but which does not grow below pH 5.8, and various other micro-organisms, including Micrococcus, Arthrobacter and coryneform bacteria. 

Micrococci comprise approximately 78% of the nonlactic bacteria in raw milk Cheddar cheese (Alford and Frazier 1950). The proteolytic system of Micrococcus freudenreichii functions optimally at 30 °C and at a pH near neutrality (Baribo and Foster 1952). An analysis of pro-teinases present in 1-year-old Cheddar cheese indicates that micrococci may contribute to proteolytic activity (Marth 1963). Proteolytic micrococci also contribute to the ripening of surface-ripened cheeses such as brick and Camembert (Lenoir 1963 Langhus et al. 1945). Micrococcal proteases probably contribute to development of ripened cheese flavor when ripening temperatures are above 10°C (Moreno and Kosikowski 1973). This effect results from degradation of /3-casein. 

A second type of bacteria is the cocci (singular, coccus) which are spherical or ovoid in shape. The individual bacterial cells of this group may occur singly [Micrococcus), in chains (Streptococcus), in pairs [Diplococcus). in irregular bunches (Staphylococcus), and in the form of cubical packets (Sarcina). The coccus does not form spores and usually is nonmotUe. See Fig. 2. 

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