Microbial Biotransformation for the Production of Steroid Medicament

Androstenedione (AD) is a steroid intermediate valuable for the production of steroid medicaments. Microbial biotransformation of phytosterol to produce AD is a well-researched area. However, low substrate solubility of phytosterol in aqueous media and nucleus degradation of AD to androstadienedione (ADD) or 9-hydroxy-AD are the major obstacles for AD production leading to detailed research for optimization of biotransformation process. In this review, microbial transformation of AD with respect to the existing methods of chemical or biochemical synthesis of AD are extensively discussed. This review examines the microbial biotransformation process and limitations for enhanced AD production. Factors affecting the effective biotransformation process to obtain AD are discussed and limitations are highlighted. The main content of this review focuses on the recent and futuristic biotechnological advances and strategies in techniques to enhance AD bioprocess

In Vitro Biotransformation in Drug Discovery

In vitro Biotransformation studies play a crucial role in drug discovery program that determine the fate of the new chemical entities (NCE’s). Enzyme rich matrices such as microsomes, hepatocytes, liver fractions and S9 fractions transform the new chemical entities to different metabolites. Metabolites could be pharmacologically important or toxic. Newly formed metabolites are identified using liquid chromatography interfaced with mass spectrometry. Identification of the biotransformation sites in the new chemical entity helps the medicinal chemists to optimize its structure and develop the NCE as a pharmaceutical drug. Screening pharmaceutical drugs using in vitro biotransformation studies assist in selecting the right new chemical entity for further in vivo studies in animal systems and later in human clinical trials

Microbioreactors and Perfusion Bioreactors for Microbial and Mammalian Cell Culture

Screening for novel producer strains and enhanced therapeutic production at reduced cost has been the focus of most of the biopharmaceutical industries. The obligation to carry out prolonged intensive pilot scale experiments gave birth to micro-scale bioreactor systems. Screening large number of microorganisms using shake flasks and benchtop bioreactors is tedious and consumes resources. Microbioreactors that mimic benchtop bioreactors are capable not only of high throughput screening of producer strains, but also aid in optimizing the growth kinetics and expression of proteins. Modern technology has enabled the collection of precise online data for variables such as optical density (OD), pH, temperature, dissolved oxygen (DO), and adjusting in mixing inside microreactors. Microbioreactors have become an irreplaceable tool for biochemical engineers and biotechnologists to perform a large number of experiments simultaneously. Another aspect that is vital to any industry is the product yield and subsequent downstream processing. Perfusion bioreactors are one of the upcoming advances in bioreactor systems that have the potential to revolutionize biologics production. This chapter intends to take a review of different aspects of microbioreactors and perfusion bioreactors including their potential in high throughput pilot studies and microbial and mammalian cell cultivation technologies

Cell-specific deletion of C1qa identifies microglia as the dominant source of C1q in mouse brain

BACKGROUND: The complement cascade not only provides protection from infection but can also mediate destructive inflammation. Complement is also involved in elimination of neuronal synapses which is essential for proper development, but can be detrimental during aging and disease. C1q, required for several of these complement-mediated activities, is present in the neuropil, microglia, and a subset of interneurons in the brain. METHODS: To identify the source(s) of C1q in the brain, the C1qa gene was selectively inactivated in the microglia or Thy-1(+) neurons in both wild type mice and a mouse model of Alzheimer’s disease (AD), and C1q synthesis assessed by immunohistochemistry, QPCR, and western blot analysis. RESULTS: While C1q expression in the brain was unaffected after inactivation of C1qa in Thy-1(+) neurons, the brains of C1qa (FL/FL) :Cx3cr1 (CreERT2) mice in which C1qa was ablated in microglia were devoid of C1q with the exception of limited C1q in subsets of interneurons. Surprisingly, this loss of C1q occurred even in the absence of tamoxifen by 1 month of age, demonstrating that Cre activity is tamoxifen-independent in microglia in Cx3cr1 (CreERT2/WganJ) mice. C1q expression in C1qa (FL/FL) : Cx3cr1 (CreERT2/WganJ) mice continued to decline and remained almost completely absent through aging and in AD model mice. No difference in C1q was detected in the liver or kidney from C1qa (FL/FL) : Cx3cr1 (CreERT2/WganJ) mice relative to controls, and C1qa (FL/FL) : Cx3cr1 (CreERT2/WganJ) mice had minimal, if any, reduction in plasma C1q. CONCLUSIONS: Thus, microglia, but not neurons or peripheral sources, are the dominant source of C1q in the brain. While demonstrating that the Cx3cr1 (CreERT2/WganJ) deleter cannot be used for adult-induced deletion of genes in microglia, the model described here enables further investigation of physiological roles of C1q in the brain and identification of therapeutic targets for the selective control of complement-mediated activities contributing to neurodegenerative disorders. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12974-017-0814-9) contains supplementary material, which is available to authorized users

Cell-specific deletion of C1qa identifies microglia as the dominant source of C1q in mouse brain.

BackgroundThe complement cascade not only provides protection from infection but can also mediate destructive inflammation. Complement is also involved in elimination of neuronal synapses which is essential for proper development, but can be detrimental during aging and disease. C1q, required for several of these complement-mediated activities, is present in the neuropil, microglia, and a subset of interneurons in the brain.MethodsTo identify the source(s) of C1q in the brain, the C1qa gene was selectively inactivated in the microglia or Thy-1+ neurons in both wild type mice and a mouse model of Alzheimer's disease (AD), and C1q synthesis assessed by immunohistochemistry, QPCR, and western blot analysis.ResultsWhile C1q expression in the brain was unaffected after inactivation of C1qa in Thy-1+ neurons, the brains of C1qa FL/FL :Cx3cr1 CreERT2 mice in which C1qa was ablated in microglia were devoid of C1q with the exception of limited C1q in subsets of interneurons. Surprisingly, this loss of C1q occurred even in the absence of tamoxifen by 1 month of age, demonstrating that Cre activity is tamoxifen-independent in microglia in Cx3cr1 CreERT2/WganJ mice. C1q expression in C1qa FL/FL : Cx3cr1 CreERT2/WganJ mice continued to decline and remained almost completely absent through aging and in AD model mice. No difference in C1q was detected in the liver or kidney from C1qa FL/FL : Cx3cr1 CreERT2/WganJ mice relative to controls, and C1qa FL/FL : Cx3cr1 CreERT2/WganJ mice had minimal, if any, reduction in plasma C1q.ConclusionsThus, microglia, but not neurons or peripheral sources, are the dominant source of C1q in the brain. While demonstrating that the Cx3cr1 CreERT2/WganJ deleter cannot be used for adult-induced deletion of genes in microglia, the model described here enables further investigation of physiological roles of C1q in the brain and identification of therapeutic targets for the selective control of complement-mediated activities contributing to neurodegenerative disorders