Genetics
RNA Silencing in Plants
RNA Silencing in Plants and the Role of Viral Suppressors
from Ana Giner, Juan Jose Lopez-Moya and Lorant Lakatos writing in RNA Interference and Viruses
The term RNA silencing refers to several pathways present in eukaryotic organisms that lead to the sequence specific elimination or functional blocking of RNAs with homology to double stranded RNAs (dsRNAs) that have previously triggered the mechanism. Besides playing important roles in developmental control, RNA silencing forms part of the defence against viruses in plants, acting as a potent antiviral mechanism. To escape from the RNA silencing-based defence, most plant viruses make use of different strategies, the most common relying in the action of viral proteins with the capacity to suppress RNA silencing. The characterization of these viral suppressors is providing useful insights to understand how RNA silencing works, revealing components and steps in the silencing pathways.
Further reading: Recent Advances in Plant Virology | RNA Interference and Viruses | RNA and the Regulation of Gene Expression
from Ana Giner, Juan Jose Lopez-Moya and Lorant Lakatos writing in RNA Interference and Viruses
The term RNA silencing refers to several pathways present in eukaryotic organisms that lead to the sequence specific elimination or functional blocking of RNAs with homology to double stranded RNAs (dsRNAs) that have previously triggered the mechanism. Besides playing important roles in developmental control, RNA silencing forms part of the defence against viruses in plants, acting as a potent antiviral mechanism. To escape from the RNA silencing-based defence, most plant viruses make use of different strategies, the most common relying in the action of viral proteins with the capacity to suppress RNA silencing. The characterization of these viral suppressors is providing useful insights to understand how RNA silencing works, revealing components and steps in the silencing pathways.
Further reading: Recent Advances in Plant Virology | RNA Interference and Viruses | RNA and the Regulation of Gene Expression
Small DNA Binding Proteins in Bacteria
Integrity of the bacterial genome is essential to survival of the organism. Further, the size of the bacterial cell necessitates significant compaction of the genomic DNA, yet availability to various cellular machineries is important for cell growth. A variety of small DNA-binding proteins encompass these functions. These proteins are sometimes referred-to as histone-like, not because of sequence or structural similarity to eukaryotic histones, but because of comparable roles in nucleoid compaction. A number of such nucleoid-associated proteins have been identified in Escherichia coli, including H-NS, Fis, Dps (DNA protection during starvation), HU, and IHF (Integration Host Factor), all of which are present at concentrations up to or even exceeding 10 mM, depending on growth conditions. These proteins have different DNA-binding properties and function together (and sometimes opposing each other) to organize genomic DNA and to regulate DNA-dependent activities.
Further reading: Functional Evolution of Bacterial Histone-Like HU Proteins
Further reading: Functional Evolution of Bacterial Histone-Like HU Proteins
Genetics of bifidobacteria
from Pablo Alvarez Martin, Simone Guglielmetti, and Baltasar Mayo in Bifidobacteria: Genomics and Molecular Aspects
Mobile genetic elements, cloning vectors and genetic manipulation of bifidobacteria.
Growth difficulties, because of their fastidious nutritive nature and oxygen sensitivity, and a lack of efficient genetic tools have impeded until recently proper development of molecular studies in Bifidobacteria. These studies, however, are critical to uncover the cross-talk between bifidobacteria and their hosts' cells, and also to prove unequivocally the supposed beneficial activities supplied through the gastrointestinal tract of mammals either endogenously or after ingestion as probiotics.
Analysis of gene sequences provided by whole genome sequencing projects has opened new avenues to decipher the genetic basis of bacteria-cell interactions and probiotic effects. However, the purposeful development of stable cloning and expression vectors based on robust replicons, either from temperate phages or resident plasmids, is additionally needed. Recent publications address the current knowledge on the mobile genetic elements of bifidobacteria (phages, plasmids, and transposons) and review the different types of vectors already available for the Bifidobacterium species, together with the transformation procedures for introducing DNA into bifidobacterial cells.
Further reading:
Mobile genetic elements, cloning vectors and genetic manipulation of bifidobacteria.
Growth difficulties, because of their fastidious nutritive nature and oxygen sensitivity, and a lack of efficient genetic tools have impeded until recently proper development of molecular studies in Bifidobacteria. These studies, however, are critical to uncover the cross-talk between bifidobacteria and their hosts' cells, and also to prove unequivocally the supposed beneficial activities supplied through the gastrointestinal tract of mammals either endogenously or after ingestion as probiotics.
Analysis of gene sequences provided by whole genome sequencing projects has opened new avenues to decipher the genetic basis of bacteria-cell interactions and probiotic effects. However, the purposeful development of stable cloning and expression vectors based on robust replicons, either from temperate phages or resident plasmids, is additionally needed. Recent publications address the current knowledge on the mobile genetic elements of bifidobacteria (phages, plasmids, and transposons) and review the different types of vectors already available for the Bifidobacterium species, together with the transformation procedures for introducing DNA into bifidobacterial cells.
Further reading:
Population genetics
Microbial population genetics is a rapidly advancing field of investigation with relevance to many areas of science. The subject encompasses theoretical issues such as the origins and evolution of species, sex and recombination. Population genetics lays the foundations for tracking the origin and evolution of antibiotic resistance and deadly infectious pathogens and is also an essential tool in the utilization of beneficial microbes.