DEEP WORK

Introduction The genus Lactobacillus belongs to the family of Lactobacteriaceae also known as lactic acid bacteria, a group of microorganisms that have been used for centuries in the preparation and processing of foods and beverages (Rose 1982; Kandler 1984; Chassy 1985, Chassy 1987). These rod-shaped, anaerobic to micro-aerophilic, non-pathogenic bacteria, which produce lactic acid as their maj..

INTRODUCTIONReplication copies the entire set of genomic DNA so that the cell can divide in two. During replication, the entire genome must be uncoiled and copied exactly. This elegant process occurs extremely fast in E. coli, where DNA polymerase copies about 1000 nucleotides per second. Although the process is slower in eukaryotes, DNA polymerase still copies 50 nucleotides per second. Many bi..

PLASMID REPLICATIONCopy Number Control and Its Role in Segregational StabilityMaintaining an upper limit to plasmid copy number may be necessary to ensure the viability of the host. In addition, to prevent plasmid loss, copy number controls must also respond rapidly in a cell inheriting few copies. This is pa1rticularlty important in the absence of a separate partitioning locus (par). No evidenc..

INTRODUCTIONNumerous plasmids of gram-positive bacteria have been identified, analyzed for their properties, and used as cloning vectors. The range of species from which plasmids have been isolated is broad, yet the properties of most of these plasmids indicate that a common gene pool had been used in their formation (36, 76). The regions of homology may involve essential or nonessential genes, ..

1. INTRODUCTIONLactobacillus, one of the lactic acid bacteria, is a natural inhabitant in the gastrointestinal tract of man and animals (Conway et al., 1987) and an important bacterium in the food industries of fermented dairy, meat, and vegetable, and also in animal feed (Chassy, 1985; Lee, 1996). In addition, it is believed to offer some benefits as probiotics in human health, such as detoxify..

4. PROTOCOL4.1. PreparationEnsure that good-quality DNA preps are available for the receiving vector and any vectors used to retrieve the insert (see Isolation of plasmid DNA from bacteria).  Identify the restriction enzymes needed and their buffer requirements for single and double digests.For PCR product inserts:Add the sequence of any desired restriction site(s) to the 50 end of each primer (..

1. THEORY Molecular cloning is an essential technique to create DNA-based experimental tools for expression in bacterial or mammalian cells. Examples of such DNA constructs include a promoter element fused to a reporter gene or a cDNA sequence under the control of a ubiquitous promoter.  Molecular cloning entails the preparation of the vector and insert DNAs, ligation of the insert into the vect..

2.5.1 Pathogen recognition Once a pathogen succeeds in breaching the innate physical barriers, it is recognized by pattern recognition receptors on immune cells, this step being the first key factor in the triggering of all subsequent immune responses. These receptors are mainly present in DCs and macrophages, but also in other cell types, such as B lymphocytes or endothelial cells, and are acti..

2.4.3 Antimicrobial peptidesAntimicrobial peptides (AMPs) are small peptides (less than 100 amino acids) with low molecular weight and direct microbicidal activities. They are mostly cationic and amphipathic, although some anionic peptides are included among them. AMPs are synthesized as pre-pro-peptides, and, once the active peptides are released by cleavage, they interact directly with pathoge..

2.4.2 ComplementThe complement system is an ancient innate immune mechanism present in both vertebrate and invertebrate species. The mammalian complement system appears more developed and is composed of ∼30 different proteins, either plasma- or membraneassociated. The proteins and glycoproteins that constitute the complement system are synthesized by hepatocytes, but significant amounts are also..