Isolation and characterization of Corynebacterium efficiens strain NCT7 from air

Abstract

As a part of academic lab in microbiology, microflora of air was sampled through settle plate technique. Morphologically distinct colonies were purified using quadrant streaking. The pure culture was preserved using glycerol stocking in triplicates. One of these glycerol stocks was revived and used for further morphological and molecular characterization.

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National College Culture Collection Centre www.ncccc.in
PG & Research Department of Biotechnology and Microbiology
National College, Tiruchirappalli- 620 001, Tamil Nadu, India
1
N4C
Isolation and characterization of Corynebacterium efficiens strain NCT7 from air
Background
As a part of academic lab in microbiology, microflora of air was sampled through settle plate
technique. Morphologically distinct colonies were purified using quadrant streaking. The pure
culture was preserved using glycerol stocking in triplicates. One of these glycerol stocks was
revived and used for further morphological and molecular characterization.
Work plan
Bergey’s manual was used to determine the lowest possible taxonomic hierarchy and the strain
was commercially outsourced for bidirectional 16S rRNA gene sequencing for species level
resolution.

National College Culture Collection Centre www.ncccc.in
PG & Research Department of Biotechnology and Microbiology
National College, Tiruchirappalli- 620 001, Tamil Nadu, India
2
N4C
Strain description: NCT7 grows stringently in nutrient agar plate at 37°C in 24 hours. Colonies
are small, round (entirely margined), flat, yellowish white color. Cells are Gram positive, non-
motile sporulative rods. Biochemical reaction implies Indole negative, methyl red positive, voges
proskauer negative and citrate positive. Triple Sugar Iron implies acid butt and alkaline slant with
no gas production. Catalase negative and oxidase positive. Pellicle formation is more prominent
in nutrient broth. The strain NCT7 was sensitive to ketoconazole, amoxicillin, clindamycin and
resistant to ampicillin.
16S rRNA gene sequencing:
Based on the colony, biochemical and
molecular characteristics, the strain
NCT7 was identified as
Corynebacterium efficiens. The 16S
rRNA gene sequences of NCT7 was
99.58% similar to Corynebacterium
efficiens (GenBank accession number:
NR_024772) and can be globally
accessed through genbank accession
number OQ255724.
The Neighbor-Joining method tree with
percentage of replicate trees in which
the associated taxa clustered together in
the bootstrap test (500 replicates) are
shown. The tree is drawn to scale, with
branch lengths in the same units as those
of the evolutionary distances used to
infer the phylogenetic tree. The
evolutionary distances were computed
using the Maximum Composite
Likelihood method and are in the units of
the number of base substitutions per site.
This analysis involved 11 nucleotide sequences. All ambiguous positions were removed for each
sequence pair (pairwise deletion option). There were a total of 1377 positions in the final dataset.
The strain NCT7 was deposited in National College Culture Collection Centre (ncccc) and are
freely available for academic and research purposes. The strain can be obtained here
www.ncccc.in