Cells and Microbes

The genes tell us what could happen in the cell Messenger RNA tells us what might happen Proteins tell us what is happening. 

In another instance of adaptation, cellular metabolism can change depending on the availability of certain substrates. A very common example of this is the use of anaerobic metabolism in muscle cells when sufficient oxygen is not available (Section 3.9). The product of this metabolic pathway is lactic acid rather than carbon dioxide and water. When oxygen is again available, the lactic acid is used to reformulate glucose and some lactic acid is metabolized to water and carbon dioxide. 

Microorganisms that produce but one metabolic product are called homofermentative, whereas those that produce many different products are called heterofermentative (Nielsen and Villadsen, 1994). Heterofermentative microbes can be manipulated in bioreactors to produce more economically valuable products by controlling the availability of metabolic substrates, and therefore determining the metabolic pathways taken. This adaptability confers a competitive advantage to the microorganism because it allows the microbe to utilize available resources to grow and reproduce in environments to which it is not completely well adapted. 

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The process of fermentation is used in various industrial settings, including the production of protein biopharmaceuticals. This process involves growing cells and microbes for the production of the desired product in large quantities under well-specified conditions. Fermentation procedures are typically optimized in a systematic manner in a pilot plant with a fermentor with a capacity on the order of 30 liters, and engineers determine the best strategies to develop fermenters with a capacity on the order of 100,000 liters (Ho and Gibaldi, 2003). 

Pirt SJ (1975) Principles of Cell and Microbe Cultivation. Blackwell, Oxford. 

The extension of the useful storage life of plant and animal products beyond a few days at room temperature presents a series of complex biochemical, physical, microbial, and economic challenges. Respiratory enzyme systems and other enzymes ia these foods continue to function. Their reaction products can cause off-davors, darkening, and softening. Microbes contaminating the surface of plants or animals can grow ia cell exudates produced by bmises, peeling, or size reduction. Fresh plant and animal tissue can be contaminated by odors, dust, iasects, rodents, and microbes. 

It is well known that pine enzymes change then behaviour and stability when they are immobilised. In the past two decades the immobilisation of microorganisms, cells and parts of cells has gradually been introduced into microbiology and biotechnology. The cell immobilisation techniques are modifications of the techniques developed for enzymes. However, the larger size of microbes has influenced the techniques. As for immobilised enzymes, two broad types of method have been used to immobilise microorganisms attachment to a support and entrapment. 

The reduction of ketones, aldehydes, and olefins has been extensively explored using chemical and biological methods. As the latter method, reduction by heterotrophic microbes has been widely used for the synthesis of chiral alcohols. On the contrary, the use of autotrophic photosynthetic organisms such as plant cell and algae is relatively rare and has not been explored because the method for cultivation is different from that of heterotrophic microbes. Therefore, the investigation using photosynthetic organisms may lead to novel biotransformations. 

Davis G, Hill HAG, Aston WJ, Higgins IJ, Turner APR 1983. Bioelectrochemical fuel cell and sensor based on a quinoprotein, alcohol dehydrogenase. Enzyme Microb Technol 5 383-388. 

The air that we breathe is full of microbial cells and spores of bacteria and fungi. Because they are extremely light they are readily are carried by wind currents. In hot weather soil, a rich source of all types of microbes, turns to dust and increases the airborne microbial population... 

The progression of human immunodeficiency virus (HIV) towards its more advanced stages is accompanied by increasing body stores of iron. Iron accumulates in macrophages as well as microglia, endothelial cells and myocytes. The iron burden is especially intense in the bone marrow, brain white matter, muscle and liver. Such excesses of iron will enhance oxidative stress, impair several already compromised immune defence mechanisms and directly promote the growth of microbes (Boelaert et ah, 1996). 

Microbial virulence is often the outcome of the complex interactions that take place as the pathogen establishes itself in the human host. The molecular determinants of pathogenicity include factors that cause damage to the host cell and those that help the microbe establish productive infection for survival [35]. The human host immune response counters the presence of these microbes with its acquired or innate immune response arsenal with outcomes that range from acute to chronic or latent infections. A clear definition of the host and microbial... 

Relatively less work has been done on immobilization of plant and animal cells and spores of microbes in silica matrixes. The main drawback is less viability of the cells in sol-gel matrices. Thus more refined methods are required to utilize harness of the whole cells entrapped in sol-gel matrices and biosensing applications. At the same time studies such as interactions between sol-gel matrices and whole cells and metabolic changes during immobilization have to be closely monitored for the exploration of new matrices and methods. 

At least some of the cannabinoid-induced modulation of immune cells, and effects on host resistance to infection, are mediated directly by binding of cannabinoids to CBRs, particularly CBR2. Host immunity to microbes, however, involves many cell types, both immune and non-immune, as well as soluble factors including cytokines, chemokines, neurocytokines, and hormones related to the HP axis. It is therefore likely that a variety of cellular and molecular mechanisms whereby cannabinoids, including THC, affect immune function. 

Biochemical industries are based on the growth of microbes such as bacteria, fungi, molds, yeasts and others. Although some microbes are grown as food, interest here is in the production of chemicals with their aid. A distinction is drawn between steps that involve cells and those that employ isolated catalytic enzymes which are metabolic products of cells. Major characteristics of microbial processes that may be contrasted with those of ordinary chemical processing include the following ... 

In other cases fullerene antibacterial action takes place after photoirradiation of fulleropyrrolidinium salts. It is not yet clear if the photodynamic action implies the participation of superoxide and hydroxyl radicals (type I mechanism) or singlet oxygen (type II mechanism) but the efficacy is really interesting with the death of more than 99.9% of bacterial and fungal cells and a special selectivity for microbes over mammalian cells (Tegos et al., 2005). Also a sulfobutyl fullerene derivative is able to inhibit environmental bacteria after photoirradiation and it exerts its action on E. coli even if incorporated in coated polymer (Yu et al., 2005). 

Foster, D. B., Philpott, D., Abul-Milh, M., Huesca, M., Sherman, P. M., and Lingwood, C. A. (1999). Phosphatidylethanolamine recognition promotes enteropathogenic E. coli and enterohemorrhagic E. coli host cells attachment. Microb. Pathog. T1, 289-301. 

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