Advances in Applied Microbiology 

About: Advances in Applied Microbiology is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Fermentation & Medicine. It has an ISSN identifier of 0065-2164. Over the lifetime, 777 publications have been published receiving 48363 citations. The journal is also known as: Applied microbiology.

Microbial metabolism of polycyclic aromatic hydrocarbons.

Abstract: Publisher Summary This chapter deals with the microbial transformation of polycyclic aromatic hydrocarbons (PAHs) The similarities and differences between the microbial and mammalian metabolism are described Bacteria, filamentous fungi, yeasts, cyanobacteria, diatoms, and other eukaryotic algae have the enzymatic capacity to oxidize PAHs that range in size from naphthalene to benzo[ a ]pyrene The hydroxylation of PAHs always involves the incorporation of molecular oxygen; however, there are differences in the mechanism of hydroxylation of PAHs by prokaryotic and eukaryotic microorganisms Bacteria oxygenate PAHs to form a dihydrodiol with a cis configuration The genes for the initial oxidation of PAHs are localized on plasmids In contrast to bacteria, fungi oxidize PAHs via a cytochrome P-450 monooxygenase to form arene oxide, which can isomerize to phenols or undergo enzymatic hydration to yield trans-dihydrodiols Multiple oxidative pathways may be involved in the cyanobacterial metabolism of PAHs Studies on PAH metabolism are entering a new era; biochemical genetic techniques such as gene cloning and transposon mutagenesis will provide new insight into the biochemistry and regulation of PAH degradative pathways

Bacteriophage host range and bacterial resistance.

Abstract: Host range describes the breadth of organisms a parasite is capable of infecting, with limits on host range stemming from parasite, host, or environmental characteristics. Parasites can adapt to overcome host or environmental limitations, while hosts can adapt to control the negative impact of parasites. We consider these adaptations as they occur among bacteriophages (phages) and their bacterial hosts, since they are significant to phage use as antibacterials (phage therapy) or to protection of industrial ferments from phage attack. Initially, we address how phage host range can (and should) be defined plus summarize claims of host ranges spanning multiple bacterial genera. Subsequently, we review bacterial mechanisms of phage resistance. These include adsorption resistance, which results in reduced interaction between phage and bacterium; what we describe as "restriction," where bacteria live but phages die; and abortive infections, where both phage and bacterium die. Adsorption resistance includes loss of phage receptor molecules on hosts as well as physical barriers hiding receptor molecules (e.g., capsules). Restriction mechanisms include phage-genome uptake blocks, superinfection immunity, restriction modification, and CRISPR, all of which function postphage adsorption but prior to terminal phage takeover of host metabolism. Standard laboratory selection methods, involving exposure of planktonic bacteria to high phage densities, tend to directly select for these prehost-takeover resistance mechanisms. Alternatively, resistance mechanisms that do not prevent bacterium death are less readily artificially selected. Contrasting especially bacteria mutation to adsorption resistance, these latter mechanisms likely are an underappreciated avenue of bacterial resistance to phage attack.

Applied and Theoretical Aspects of Virus Adsorption to Surfaces

Abstract: Publisher Summary This chapter highlights how the current understanding of the mechanisms and factors influencing virus adsorption can be used to interpret and control virus behavior in the environment. An understanding of factors controlling the interaction has already led to new and improved methods for the concentration of viruses from water, and their isolation from the environment. It is evident that not all viruses behave alike toward a solid under identical conditions. Under most natural conditions viruses with a low isoelectric point appear to be more poorly adsorbed to most solid surfaces. This must be taken into consideration when evaluating concentration or treatment systems which involve adsorption. This phenomenon is also important in determining the transport of viruses in the environment. Certain enteric viruses appear to adsorb less readily to soils and aquatic sediments than others. Thus their potential transport to groundwater may be greater and they may be less likely to settle in surface waters. To take into consideration these differences in virus behavior, it is perhaps best to use viruses with widely varying isoelectric points or marked differences in hydrophobicity to evaluate the extremes in virus interaction with a given surface which could occur.

Stabilization of enzymes against thermal inactivation.

Abstract: Publisher Summary In order to be suitable for technological applications, catalysts should be stable under operational conditions for weeks or months. With continuous research it is found that enzymes can be stabilized against thermal inactivation. There are three methods that can be employed in the attempt to make enzymes more thermostable: immobilization, chemical modification, and inclusion of additives. Using these methods, rate constants of thermo inactivation of many enzymes have been reduced by as much as 103–105 times; there are enzymes that even without any stabilization display remarkable thermal resistance. For example, Bacillus stearothemphilus a-amylase retains 90% of its activity after 1 hour at 90°C. It is found that at 100°C in 0.1 N HCI, the halflife of adenylate kinase exceeds 30 minutes. Bacillus lichenifomnis amylase continuously operates at 100–115°C. The aforementioned enzymes are made of the same building blocks as other, far less thermostable enzymes. Developments in protein chemistry and the understanding of thermophily, along with sensible analyses of enzyme thermoinactivation and use of common sense, will undoubtedly lead to many new approaches to stabilization of enzymes at high temperatures.