PHYLOGENETIC ANALYSIS OF COLD SHOCK PROTEINS IN PSEUDOMONAS SPECIES
Short Communication
KAVYA SANGU
1
, P. VASANTH RAJ
1,2
, NEERAJ PALIWAL
2
, K. VENKATESKUMAR
2
, ROHINI KARUNAKARAN*
3
1
Manipal College of Pharmaceutical Sciences, Manipal University, Manipal, India,
2
Faculty of Pharmacy and
3
Received: 23 May 2016 Revised and Accepted: 21 Jun 2016
Faculty of Medicine, AIMST
University, Semeling, Bedong, Kedah, Malaysia
Email: rohinik23@gmail.com
ABSTRACT
Objective: The present study focuses on the determination of the relativity of the different types of cold shock proteins.
Methods: Our study was to determine the relationship among the types of CSPs. Three different strains of pseudomonas genus, Pseudomonas
fluorescens, Pseudomonas aeruginosa and Pseudomonas putida were chosen and molecular profiling was performed. The sequences thus obtained
were subjected to multiple sequence analysis in ClustalW database. The molecular evolution and phylogenetic study have been carried out using
phylodraw.
Results: The phylogenetic analysis has clearly revealed the evolutionary pattern of cold shock proteins in pseudomonas species and the current
stress of mutation among the strains.
Conclusion: Phylogenetic analysis of cold shock proteins has clearly shown that important conserved sequences can be very useful to study the
phylogeny of bacteria.
Keywords: Cold Shock Proteins, Phylogenetic Analysis, Pseudomonas, CspD
© 2016 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4. 0/ )
Microorganisms are known to survive under a wide range of
environmental conditions ranging from hot springs to ice-cold Polar
Regions and from salt brines to sulphur vents. However, the
occurrence of microorganisms at near zero or subzero temperatures
has always posed the riddle to biologists. Research regarding cold-
adapted microorganisms not only help to understand the molecular
mechanisms of cold adaptation, but also projects the significant and
potential use of the organisms in various biotechnological, industrial
and healthcare applications [1, 2]. Most often, bacteria have to adapt
with more than one extreme condition at a given single time in
natural environmental condition. Some of the places which are frigid
viz. Antarctica with such adverse environment where bacteria have
to be cold-tolerant as well as desiccation-tolerant [2, 3]. Moreover,
bacteria dwelling at the bottom of the ocean ought to be salt-tolerant
as well as pressure-tolerant. Interestingly, fewer known bio-
molecules enable the microorganisms to cope up with more than
one stress factor at a time. Microorganisms utilize bio-molecules and
interlink the mechanisms involved in the process to different
environmental stress factors for adaptation [2]. Among various bio-
molecules which are responsible for developing cold resistance for
microorganisms, the cold shock proteins (CSPs) play a significant
role [4]. CSPs are protein domains of about 70 amino acids which
have been found in prokaryotic and eukaryotic DNA-binding
proteins. These so-called cold shock proteins are thought to help the
cell to live in temperatures lower than optimum growth
temperature, possibly by condensation of the chromosome and
prokaryotic nucleoid organization [4]. CSP’s are nucleic acid binding
proteins and are well conserved in plants, animals and bacteria.
Prokaryotes and eukaryotes exhibit cold shock response with the
production of cold shock proteins to overcome detrimental cold
shock effects. CSPs play a significance role in cell physiology and
studies have been reported that they bind mRNA and regulate in
ribosomal translation [4].
Temperature downshifts the cold shock response which has been
studied in detail using model systems such as Escherichia coli and
Bacillus subtilis [2, 6]. Acclimation phase (lag period of cell growth)
was observed when an exponentially growing culture of Escherichia
coli is shifted from 37 °C to 15 °C [2, 6]. This phase is characterized
by the induction of cold shock proteins against a severe inhibition of
general protein synthesis and leads to the growth resumption.
Studies have shown that nine CSPA homologues were found in
Escherichia coli, in which only CspA, CspB, CspG and CspI were found
to be cold shock inducible [7-10]. Moreover, Xia and team have
suggested that the functions of the CspA family members may overlap
which can substitute for each other during cold acclimation [11].
In this study, a preliminary investigation was carried out to
determine the relativity among various types of CSPs where
complete molecular profiling was performed for the microorganism,
necessitating different strains of the microorganism to be
considered. For the purpose, three different strains of an Antarctic
bacterium (pseudomonas genus) were chosen and studied. The
strains used in this study were, Pseudomonas fluorescens,
Pseudomonas aeruginosa and Pseudomonas putida among which
Pseudomonas aeruginosa is increasingly recognized as an emerging
opportunistic pathogen of significant clinical relevance.
The key word ‘Cold Shock Proteins’ yielded protein sequences from
GenBank [URL: http://www.ncbi.nlm.nih.gov/Genbank/]; Synonyms
to cold shock proteins were also collected. CSP coding proteins were
chosen selectively from the protein sequences. The other proteins
such as partial cold shock proteins were omitted from the analysis
data. Total 225 protein sequences were collected from three
different species, Pseudomonas fluorescens, Pseudomonas aeruginosa,
Pseudomonas putida and geographical locations such as China, India,
Japan, Spain and USA were used for the analysis.
Multiple sequence alignment was performed using the software
program CLUSTAL X (1.83) [12]. From the multiple sequence
alignment, the guide tree was derived by using phylodraw software
(Version 1.0). To justify the confidence of the clades, re-sampling
method (bootstrap) was used with 100 trails.
Alignments were analyzed and phylogenetic relationships among
the sequences were established using different procedures:
Neighbor-Joining (NJ) [13], Fast Minimum Evolution (Fast ME) [14].
Three different strains of pseudomonas were selected initially and
the Phylogenetic tree was constructed based on the Mega software.
Fig. 1 shows the Phylogenetic tree of Cold Shock Proteins in
The final tree was displayed by using MEGA 3.1 [15], the nodes and
clades of CSPs were traced out by visual examination.
International Journal of Pharmacy and Pharmaceutical Sciences
ISSN- 0975-1491 Vol 8, Issue 8, 2016