Daily Archives: April 2, 2014

Genetic Engineering by Nopparat
Genetic Engineering present by Nopparat Chartmontree (Mind) Biology major@Phetchaburi Rajabhat University Smile Bio ... ^^

By: prasert sert

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Genetic Engineering by Nopparat - Video

PUBLIC RELEASE DATE:

1-Apr-2014

Contact: Vicki Cohn vcohn@liebertpub.com 914-740-2100 x2156 Mary Ann Liebert, Inc./Genetic Engineering News

New Rochelle, NY, April 1, 2014 -- Rare, very small embryonic-like stem cells (VSELs) isolated from human adult tissues could provide a new source for developing regenerative therapies to repair complex tissues damaged by disease or trauma. The ability of these most-primitive, multipotent stem cells to differentiate into bone, neurons, connective tissue, and other cell types, and the proper criteria for identifying and isolating VSELs, are described in two articles in Stem Cells and Development, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The articles are available on the Stem Cells and Development website.

Russ Taichman and coauthors, University of Michigan (Ann Arbor) and NeoStem (New York, NY), implanted human VSELs into the cavity created by a cranial wound and provided the first demonstration that they could generate tissue structures containing multiple cell types. Their work is presented in "Human and Murine Very Small Embryonic-Like (VSEL) Cells Represent Multipotent Tissue Progenitors, In Vitro and In Vivo."

Malwina Suszynska et al., University of Louisville, KY, and Pomeranian Medical University (Szczecin) and Jagiellonian University (Krakow), Poland, explore the challenges in isolating these rare stem cells and the importance of not confusing VSELs with other types of embryonic or reprogrammed adult pluripotent stem cells, or with monopotent adult stem cells. In the Issues in Development article "The Proper Criteria for Identification and Sorting of Very Small Embryonic-Like Stem Cells (VSELs), and Some Nomenclature Issues," the authors present the most current descriptions and terminology for characterizing VSELs.

"I find the data presented by the Taichman group to be compelling and challenging. However, the current debate as to the significance of the body of publications concerning VSELs can only be resolved by a cooperative investigation across laboratories using identical methodologies and source materials," says Editor-in-Chief Graham C. Parker, PhD, The Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI.

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About the Journal

Stem Cells and Development is an authoritative peer-reviewed journal published 24 times per year in print and online. The Journal is dedicated to communication and objective analysis of developments in the biology, characteristics, and therapeutic utility of stem cells, especially those of the hematopoietic system. Complete tables of content and a free sample issue may be viewed on the Stem Cells and Development website.

More here:
First evidence that very small embryonic-like stem cells

23 hours ago

Microbiologists from Trinity College Dublin have discovered that an identical protein is used differently by two species of bacteria to help them cope with distinct types of environmental stress. The discovery reveals an extraordinary level of versatility in the way different genes are 'switched on' in bacteria, which in turn helps to explain how they evolve so quickly.

The microbiologists showed that the same protein, called 'OmpR, which is responsible for binding to specific sections of DNA, governs the way a large cohort of genes function in both a human-friendly strain of Escherichia coli (E. coli) and in the potentially deadly Salmonella enterica serovar Typhimurium (S. Typhimurium).

In E. coli, OmpR is central to the ability of the bacterium to survive sudden stress caused by water moving in and out of its cells due to changing external conditions. In S. Typhimurium, however, OmpR is a key regulator of a series of actions that enable individual bacteria to respond to and survive acid stress. Such conditions are experienced, for example, in the hostile environment found in the bacteria-destroying vacuoles of macrophages, which are cells of the immune system that Salmonella can defeat using specialist pathogenic genes.

The microbiologists identified all the OmpR binding sites in the chromosomes of both species and investigated the features that attracted OmpR to them. The sites were rich in the DNA bases adenine (A) and thymine (T), which bind to one another to help form the classic double helix structure associated with DNA.

Importantly, the DNA of S. Typhimurium alters its shape after a bacterium is exposed to acid. This change in shape, called DNA relaxation, enhances the attractiveness of the OmpR binding sites for the OmpR protein. The same relaxation does not occur in E. coli.

Professor and Head of Microbiology at Trinity, Charles Dorman, said: "This work shows that DNA is not a passive partner when genes are switched on, but that it is an active and dynamic participant in the process. And, among the many OmpR targets possessed by S. Typhimurium that are not present in E. coli are the genes that make Salmonella pathogenic, and problematic for people."

Scientists believe that the pathogenic genes were acquired through horizontal gene transfer. This process is mediated by direct contact between bacteria, by special viruses called bacteriophages, or by direct uptake of DNA from the environment. The transfer essentially represents the passing of DNA's all-important codes between individuals, and is often associated with the development and evolution of antibiotic resistance.

The scientists suspect that this DNA code sharing occurred after Salmonella and E. coli separated from their last common ancestor, earlier in the two species' unique evolutionary journeys, which is why the pathogenic genes are not present in E. coli. The DNA sequences of these genes confirm that they are very rich in A and T bases, which is a key characteristic they share with the OmpR binding sites.

Functionally, this means that these genes have the appropriate structural profile for rapid interaction with the OmpR DNA binding protein, which regulates when, and to what degree, they are 'switched on'. This profile, coupled with the DNA relaxation that accompanies acid stress in Salmonella, may have allowed OmpR to 'tame' these imported genes and embed them in the acid stress response of Salmonella bacteria.

Continued here:
Versatility in genetic expression aids rapid microbial evolution