Isolation and characterization of Staphylococcus xylosus strain NCT36 from marine fish gut

Abstract

As a part of academic lab in bacteriology, marine fish gut samples were serially diluted and plated onto nutrient agar plates. Following incubation, morphologically unique colonies were segregated via quadrant streaking. These pure cultures were preserved using glycerol stocking in triplicates. One of these glycerol stocks were revived and used for further morphological and molecular characterization.

Full text

National College Culture Collection Centre
PG & Research Department of Biotechnology and Microbiology
National College, Tiruchirappalli- 620 001, Tamil Nadu, India
1
Isolation and characterization of Staphylococcus xylosus strain NCT36 from marine fish
gut
Background
As a part of academic lab in bacteriology, marine fish gut samples were serially diluted and plated
onto nutrient agar plates. Following incubation, morphologically unique colonies were
segregated via
quadrant streaking.
These pure cultures
were preserved using
glycerol stocking in
triplicates. One of
these glycerol stocks
were 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
PG & Research Department of Biotechnology and Microbiology
National College, Tiruchirappalli- 620 001, Tamil Nadu, India
2
Results
Strain description: NCT36 grows well in nutrient agar plate at 37°C in 24 hours. Colonies are
small, orange pigmented, round with smooth edges. Cells are Gram positive, non-spore forming,
and non-motile cocci. Biochemical reaction implies Indole negative, methyl red positive, voges
proskauer negative and citrate positive. Triple Sugar Iron implies alkaline butt and acid slant with
no gas production. Catalase positive and oxidase positive. The strain NCT36 was sensitive to
streptomycin (9mm), amoxicillin (7mm), rifampicin (8mm), penicillin (9mm), and resistant to an
ampicillin. Primary screening for amylases and lipases reveals positive reactions.
16S rRNA gene sequencing:
Based on the colony and biochemical characteristics, the strain NCT36 was identified as
Staphylococcus xylosus. NCT36 was 99.43% similar to Staphylococcus xylosus (GenBank
accession number: NR_036907). 16S rRNA gene sequence of NCT36 can be globally accessed
through genbank accession number OQ271428.
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 1258
positions in the final dataset.
The strain NCT36 was deposited in National
College Culture Collection Centre (ncccc) and are
freely available for academic and research
purposes. The strain can be order here
www.ncccc.in.