Rapid Isolation of Speci„c cDNAs or Genes by PCR

2016 ◽  
pp. 47-62
Keyword(s):  
Author(s):  
D Samba Reddy ◽  
Tina Reddy

A transgenic animal is a genetically modified species in which researchers have modified an existing gene or genes by genetic engineering techniques. Genetic modification involves the mutation, insertion, or deletion of genes. Mouse is the most widely used mammalian species for creating transgenic lines. There are two types of transgenic animals: (i) gene deleted (“knock-out”) and (ii) gene overexpressed (“knock-in”). The loss or gain of gene activity often causes changes in a mouse's phenotype, which includes appearance, behavior and other observable characteristics. Knockout mice are key animal models for studying the role of genes which have been sequenced but whose functions have not been determined.  They include constitutive knockouts (gene deleted since birth) and conditional knockout (gene turned off later after birth).  The first knockout mouse was created in 1989 by Mario Capecchi, Martin Evans, and Oliver Smithies, for which they were awarded the 2007 Nobel Prize in Physiology or Medicine.  Transgenic mouse models have revolutionized the biomedical research and provided a power tool for understanding health and disease. Transgenic animals have been created for bulk production of biotechnology and pharmaceutical products.  In 2009, the FDA approved the first human biological drug ATryn, an anticoagulant extracted from the transgenic goat's milk. The recently discovered CRISPER gene editing technology is providing new frontiers in correcting abnormal genes and hopefully provide cures for genetic diseases in the future.    


2018 ◽  
Vol 24 (15) ◽  
pp. 1639-1651 ◽  
Author(s):  
Xian-ling Qian ◽  
Jun Li ◽  
Ran Wei ◽  
Hui Lin ◽  
Li-xia Xiong

Background: Anticancer chemotherapeutics have a lot of problems via conventional Drug Delivery Systems (DDSs), including non-specificity, burst release, severe side-effects, and damage to normal cells. Owing to its potential to circumventing these problems, nanotechnology has gained increasing attention in targeted tumor therapy. Chemotherapeutic drugs or genes encapsulated in nanoparticles could be used to target therapies to the tumor site in three ways: “passive”, “active”, and “smart” targeting. Objective: To summarize the mechanisms of various internal and external “smart” stimulating factors on the basis of findings from in vivo and in vitro studies. Method: A thorough search of PubMed was conducted in order to identify the majority of trials, studies and novel articles related to the subject. Results: Activated by internal triggering factors (pH, redox, enzyme, hypoxia, etc.) or external triggering factors (temperature, light of different wavelengths, ultrasound, magnetic fields, etc.), “smart” DDSs exhibit targeted delivery to the tumor site, and controlled release of chemotherapeutic drugs or genes. Conclusion: In this review article, we summarize and classify the internal and external triggering mechanism of “smart” nanoparticle-based DDSs in targeted tumor therapy, and the most recent research advances are illustrated for better understanding.


Author(s):  
Darlene Ana Souza Duarte ◽  
Martine Schroyen ◽  
Rodrigo Reis Mota ◽  
Sylvie Vanderick ◽  
Nicolas Gengler

AbstractBoar taint is an unpleasant odor in male pig meat, mainly caused by androstenone, skatole, and indole, which are deposited in the fat tissue. Piglet castration is the most common practice to prevent boar taint. However, castration is likely to be banished in a few years due to animal welfare concerns. Alternatives to castration, such as genetic selection, have been assessed. Androstenone and skatole have moderate to high heritability, which makes it feasible to select against these compounds. This review presents the latest results obtained on genetic selection against boar taint, on correlation with other traits, on differences in breeds, and on candidate genes related to boar taint. QTLs for androstenone and skatole have been reported mainly on chromosomes 6, 7, and 14. These chromosomes were reported to contain genes responsible for synthesis and degradation of androstenone and skatole. A myriad of work has been done to find markers or genes that can be used to select animals with lower boar taint. The selection against boar taint could decrease performance of some reproduction traits. However, a favorable response on production traits has been observed by selecting against boar taint. Selection results have shown that it is possible to reduce boar taint in few generations. In addition, modifications in diet and environment conditions could be associated with genetic selection to reduce boar taint. Nevertheless, costs to measure and select against boar taint should be rewarded with incentives from the market; otherwise, it would be difficult to implement genetic selection.


2020 ◽  
Vol 26 (9) ◽  
pp. 1422-1427 ◽  
Author(s):  
Seth J. Zost ◽  
Pavlo Gilchuk ◽  
Rita E. Chen ◽  
James Brett Case ◽  
Joseph X. Reidy ◽  
...  

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