Distribution of isoprenoid quinone structural types in bacteria and their taxonomic implication.

Publisher Summary This chapter discusses analysis of isoprenoid quinones. The respiratory quinones represent an important group of isoprenoid lipids that occur in the cytoplasmic membrane of most prokaryotes. Two major structural groups of bacterial isoprenoid quinones can be recognized: the naphthoquinones and benzoquinones. Naphthoquinones can be divided further into two major types: phylloquinones and menaquinones. In choosing the methods to be employed for the extraction and purification of menaquinones, ubiquinones, and related quinones one must take into account the susceptibility of these compounds to degradation. Isoprenoid quinones are quite rapidly photo-oxidized in the presence of oxygen and strong light. They are also particularly susceptible to alkaline conditions (the last limitation rules out alkaline saponification). Thus, it is preferable to conduct extraction and subsequent purification procedures fairly rapidly, avoiding extremes of pH and strong light. The composition of natural mixtures of bacterial quinones can be investigated using partition chromatography. Separation of compounds by partition chromatography is generally on the basis of relative solubilities, which in the case of homologous series such as ubiquinones and menaquinones is determined by the length and degree of hydrogenation of the multiprenyl side chain.

Analysis of isoprenoid quinones

Summary: Within the past 10 years, treatment and diagnostic guidelines for nontuberculous mycobacteria have been recommended by the American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA). Moreover, the Clinical and Laboratory Standards Institute (CLSI) has published and recently (in 2011) updated recommendations including suggested antimicrobial and susceptibility breakpoints. The CLSI has also recommended the broth microdilution method as the gold standard for laboratories performing antimicrobial susceptibility testing of nontuberculous mycobacteria. This article reviews the laboratory, diagnostic, and treatment guidelines together with established and probable drug resistance mechanisms of the nontuberculous mycobacteria.

Antimicrobial susceptibility testing, drug resistance mechanisms, and therapy of infections with nontuberculous mycobacteria.

Antibiotic susceptibility testing (AST) specifies effective antibiotic dosage and formulates a profile of empirical therapy for the proper management of an individual patient’s health against deadly infections. Therefore, rapid diagnostic plays a pivotal role in the treatment of bacterial infection. In this article, the authors review the socio-economic burden and emergence of antibiotic resistance. An overview of the phenotypic, genotypic, and emerging techniques for AST has been provided and discussed, highlighting the advantages and limitations of each. The historical perspective on conventional methods that have paved the way for modern AST like disk diffusion, Epsilometer test (Etest), and microdilution, is presented. Several emerging methods, such as microfluidic-based optical and electrochemical AST have been critically evaluated. Finally, the challenges related with AST and its outlook in the future are presented.

https://www.mdpi.com/2075-4418/9/2/49/pdf

Current and Emerging Methods of Antibiotic Susceptibility Testing.

This review presents an update on the current knowledge of the secondary metabolite potential of the major fungal species used in industrial biotechnology, i.e., Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei. These species have a long history of safe use for enzyme production. Like most microorganisms that exist in a challenging environment in nature, these fungi can produce a large variety and number of secondary metabolites. Many of these compounds present several properties that make them attractive for different industrial and medical applications. A description of all known secondary metabolites produced by these species is presented here. Mycotoxins are a very limited group of secondary metabolites that can be produced by fungi and that pose health hazards in humans and other vertebrates when ingested in small amounts. Some mycotoxins are species-specific. Here, we present scientific basis for (1) the definition of mycotoxins including an update on their toxicity and (2) the clarity on misclassification of species and their mycotoxin potential reported in literature, e.g., A. oryzae has been wrongly reported as an aflatoxin producer, due to misclassification of Aspergillus flavus strains. It is therefore of paramount importance to accurately describe the mycotoxins that can potentially be produced by a fungal species that is to be used as a production organism and to ensure that production strains are not capable of producing mycotoxins during enzyme production. This review is intended as a reference paper for authorities, companies, and researchers dealing with secondary metabolite assessment, risk evaluation for food or feed enzyme production, or considerations on the use of these species as production hosts.

/pdf/safety-of-the-fungal-workhorses-of-industrial-biotechnology-3kg2uk9zl3.pdf

Safety of the fungal workhorses of industrial biotechnology: update on the mycotoxin and secondary metabolite potential of Aspergillus niger , Aspergillus oryzae , and Trichoderma reesei

Investigation of the conditions of cultivation of the mold Penicillium notatum in connection with the formation of penicillin led to the observation that occasionally cultures were obtained with shaking and aeration which, after a certain stage of development, had a greenish cast to them. This type of pigmentation is quite unlike the yellow water-soluble pigment, chrysogenin, commonly formed in cultures of the mold, and apparently is insoluble in the liquid portion of the medium, tending to settle out with the cell material. Microscopic examination of a portion of the pigmented mass revealed that typical conidiospore formation had occurred in the submerged cultures and that the greenish hue of such cultures is due to the grass-green-colored spores of the mold. Their color resembles the spores characteristic of surface cultures. Figures 1 and 2 are photomicrographs of material from typical sporeforming submerged cultures. Figure 1 represents the spore-bearing structures (penicilli) after separation from the clusters of spores, which are shown in figure 2. Figure 3 shows, for comparison, the typical spores and accessory structures in the aerial mycelium of a surface culture of the same strain of P. notatum. The characteristic spore apparatus, including sporophores, metulae, sterigmata, and conidiospores, are present in the submerged culture and appear to be essentiallv the same as those in surface cultures. The long chains of spores are usually absent since they are broken off by the vigorous agitation the culture is subjected to and exist free, singly or in clusters. In manv instances in figures 1 and 3 single spores still remain attached to the sterigmata. These probably are incompletely formed spores. However, in figure 1 one chain does appear intact (C). The formation of spores under submerged conditions by molds belonging to the genus Penicillium, and, for that matter, to the class Fungi Imperfecti as a whole, is unique and has not, to our knowledge, hitherto been recorded in the literature. Invariabily, molds of this class which sporulate readily when grown on the surface of solid or liquid media growprofusely under submerged conditions, but the cell material consists only of vegetative mycelium. Although it is difficult to make an accurate microscopic count because tremerndous numbers of spores are trapped in clusters of mycelium, rough counts show as high as 400 million free spores per ml. This figure is low by a con-

Microbiological Aspects of Penicillin: V. Conidiospore Formation in Submerged Cultures of Penicillium Notatum.

Coenzyme Q. XVII. Isolation of coenzyme Q10 from bacterial fermentation

Available information on the production of penicillin deals exclusively with surface cultures of Pencillium notatum in shallow layers of medium (Abraham et al., 1941; Challinor, 1942; Clutterbuck et al., 1932; Fleming, 1929, 1932; Hobby et al., 1942; Kocholaty, 1942; Reid, 1935). The need for large amounts of this therapeutic agent led to investigation of submerged cultures of P. notatum as a practicable process for large-scale production of penicillin. This paper shows that substantial amounts of penicillin can be produced in submerged cultures of P. notatum under suitable conditions and also presents some characteristics of the process.

Microbiological Aspects of Penicillin: IV. Production of Penicillin in Submerged Cultures of Penicillium Notatum.

Cyanide ion in production of vitamin b12

This invention relates to improved processes for the production of penicillin. Throughout this application where the term penicillin is used, it is intended to define that antibacterial substance produced by molds belonging to the genus Penicillium when the pH of the medium is near neutral...

Process for the production of penicillin

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