Metagenomic Library Screening
Metagenomic Library Screening - Related Videos
16:05
Large-Scale Screens of Metagenomic Libraries
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Cited by 9 •
2007
Metagenomic libraries archive large fragments of contiguous genomic sequences from microorganisms without requiring prior cultivation. Generating a ...
10:21
A High Throughput Screen for Biomining Cellulase Activity from Metagenomic Libraries
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Cited by 24 •
2011
This protocol describes a high throughput screen for cellulolytic activity from a metagenomic library expressed in Escherichia coli. The screen is solution based and highly automated, and uses one-pot chemistry in 384 well microplates with the final readout as an absorbance measurement.
11:59
Competitive Genomic Screens of Barcoded Yeast Libraries
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Cited by 44 •
2011
We have developed comprehensive, unbiased genome-wide screens to understand gene-drug and gene-environment interactions. Methods for screening these mutant collections are presented.
12:28
Bacterial Inner-membrane Display for Screening a Library of Antibody Fragments
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Cited by 8 •
2016
We provide a method to simultaneously screen a library of antibody fragments for binding affinity and cytoplasmic solubility by using the Escherichia coli twin-arginine translocation pathway, which has an inherent quality control mechanism for intracellular protein folding, to display the antibody fragments on the inner membrane.
08:10
Multi-enzyme Screening Using a High-throughput Genetic Enzyme Screening System
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Cited by 7 •
2016
This work presents a method of high-throughput screening using a universal genetic enzyme screening system that can be theoretically applied to over 200 enzymes. Here, the single screening system identifies three different enzymes (lipase, cellulase, and alkaline phosphatase) by simply changing the substrate used (p-nitrophenyl acetate, p-nitrophenyl-β-D-cellobioside, and phenyl phosphate).
FAQs
The approach analyzes DNA recovered from an environmental community rather than requiring each organism to grow in the laboratory. Consequently, genetic material from organisms that are difficult or impossible to culture can still enter the library. This expands biological discovery beyond cultured isolates and allows researchers to investigate genes associated with previously inaccessible proteins, traits, and metabolic pathways.
Sequence-based screening searches library clones for particular nucleotide sequences, whereas function-based screening identifies clones that express a detectable activity, such as an enzymatic reaction. The first strategy begins with genetic information of interest; the second begins with a biological function. Using either approach can connect environmental DNA fragments with genes or activities relevant to biology and biotechnology.
Environmental DNA is fragmented so individual pieces can be inserted into host vectors, which carry those pieces as a library of cloned sequences. Host cells then provide the setting in which library fragments can be maintained and, for functional screening, expressed. This arrangement makes it possible to recover a DNA fragment after detecting either its sequence or its biological activity.
A typical workflow begins with collecting environmental DNA and fragmenting it into suitable pieces. Researchers clone those fragments into host vectors to create a library, then screen the library for a target nucleotide sequence or expressed function. Positive clones are recovered and analyzed, allowing the detected genetic material to be associated with a trait, protein, or metabolic pathway.
A positive clone indicates that a library fragment matches the selected sequence or produces the screened activity. Researchers recover that clone and analyze its DNA to connect the observed result with genetic information. This interpretation can reveal candidate genes, proteins, or pathways, while functional positives additionally provide evidence that the inserted environmental DNA expresses a biologically relevant activity.
The method supports discovery of new enzymes, bioactive compounds, resistance determinants, and ecological functions from environmental communities. These findings can contribute to biotechnology and medicine by identifying useful activities or biologically important determinants, while environmental research can use them to investigate functions and metabolic pathways present in microbial communities that are not fully represented by cultured organisms.