Many microbes are in an attached state in natural environments and they play important roles as agents of geochemical change at a global scale. A systematic way to sort out these microbes based on their growth rates is introduced. Then, the relation between solid surfaces and microbes has been reviewed as follows. The surface characteristics, such as “surface charge” and “hydrophobicity and hydrophilicity” of microbial cells, are explained by referring to the results obtained for the microbes isolated from soil environments. It is also shown that there is a polymer layer at the cell surface, which makes the mechanism of cell attachment totally different from that proposed based on the conventional theories. The biofilm, a sort of city for microbes, is also introduced as an important habitat to survive in harsh natural environments.
The cell surface changes sensitively with environmental stimuli because it locates at the interface between the cell and the environment. Bacteria have their elaborate systems against a variety of stresses as well as other organisms and possess abilities to adapt to, recover from, or obtain tolerance for stressful situations. In some cases, damages to the cell surface are likely to cause directly cell death. Here, an outline of our studies on the effect of heat stress on the structure and functions of cell surface and on the role of cell surface with regard to the heat resistance of bacteria is described.
In natural and industrial environments, bacteria exist in adhering to solid surfaces such as metals, plastics, glass, soil particles, plant and animal tissues. Adherent bacteria are resistant to chemicals and heat compared with their planktonic cells, and may cause serious problems in bioprocess engineering, medicine and food processings. In order to clarify these observations and phenomena, it is necessary to study physicochemically the microstructure of solid surfaces, structure and properties of bacterial cell surfaces, mechanisms of bacterial adhesion and their correlations.
Antimicrobial finishings of industrial materials, products, foods, clothings and shelters have been remarkably developed in Japan and is now progressing. In addition, frequent occurrence of the infectious diseases such as Vero cytotoxin-producing Escherichia coli O-157, Legionella pneumophila, Staphylococcus aureus and resistant bacteria against antibiotics brings a boom of antimicrobial finishing and goods. The first aim of antimicrobial finishing for industrial materials and products is to protect from microbial deterioration and degardation. The second is to inhibit the growth of harmful microbes on the surfaces of industrial products. The third is to maintain hygiene in living environment. In future, highly functional antimicrobial chemicals will be developed and a greater number of industrial products will be processed with the chemicals. However, it is necessary for the chemicals processed to change into biodegradable and environmentally friendly substances immediately in a moderate condition.
In order to identify the existence and/or the structure of some organic compounds by Ga-primary ion TOF-SIMS, the collection and retrieval of spectra from references and standard materials have been performed as the case of IR and/or XRD. However, when the collection of correct SIMS spectra is not sufficient, the inference of fragment patterns of compounds to be identified is required. In this case, it was recognized that the roles of chemical parameters like bonding energy between radicals, electron affinity of atoms and radicals, and so on were important; and for the present, the construction of the so called general analytical procedure applicable to almost all organic compounds was difficult to establish.
Performance of a soft X-ray emission spectrometer employing a thinned back-illuminated CCD detector and a Rowland circle of 1 m in radius was examined in the energy range of 58–1254 eV. The K and L emission spectra of metal oxides, graphite, silicon compounds etc. stimulated by a low-energy electron were in good agreement with those obtained in the previous observations with conventional MCP detectors. The examinations suggested that well-resolved spectra can be obtained by several-ten second measurements when the distance between an optical source-point (sample) and grating is 7–8 cm.
About 330 years have passed since Newton found the spectroscopy. During this period, Roentgen and Thomson discovered X-ray and electrons, respectively. Then, Auger determined Auger process using a cloud chamber invented by Wilson, and Siegbahn established the basis of X-ray photoelectron spectroscopy using his specially designed electron analyzer. Now we enjoyed modern electron spectroscopy instruments established by the efforts of many scientists and engineers, and now the electron spectroscopy is an indispensable technique to characterize the surfaces of materials in laboratories as well as in industries. This paper may guide us to the future development of this technique by tracing the development of electron spectroscopy.