Rosamma, Philip; Sreedevi N, Kutty(John Wiley & Sons, 2008)
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Abstract:
Yeasts are ubiquitous in their distribution and populations mainly depend on the
type and concentration of organic materials. The distribution of species, as well as
their numbers and metabolic characteristics were found to be governed by existing
environmental conditions. Marine yeasts were first discovered from the Atlantic
Ocean and following this discovery, yeasts were isolated from different sources, viz.
seawater, marine deposits, seaweeds, fish, marine mammals and sea birds. Nearshore
environments are usually inhabited by tens to thousands of cells per litre of
water, whereas low organic surface to deep-sea oceanic regions contain 10 or fewer
cells/litre. Aerobic forms are found more in clean waters and fermentative forms in
polluted waters. Yeasts are more abundant in silty muds than in sandy sediments.
The isolation frequency of yeasts fell as the depth of the sampling site is increased.
Major genera isolated in this study were Candida, Cryptococcus, Debaryomyces and
Rhodotorula. For biomass estimation ergosterol method was used. Classification and
identification of yeasts were performed using different criteria, i.e. morphology, sexual
reproduction and physiological/biochemical characteristics. Fatty acid profiling or
molecular sequencing of the IGS and ITS regions and 28S gene rDNA ensured
accurate identification.
Swapna P, Antony; Bright Singh, I S; Sudheer, N S; Vrinda, S; Priyaja, P; Rosamma, Philip(Elsevier, January , 2011)
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Abstract:
A crustinlike
antimicrobial peptide from the haemocytes of giant tiger shrimp, Penaeus monodon was
partially characterized at the molecular level and phylogenetic analysis was performed. The partial coding
sequence of 299 bp and 91 deduced amino acid residues possessed conserved cysteine residues characteristic
of the shrimp crustins. Phylogenetic tree and sequence comparison clearly confirmed divergence
of this crustinlike
AMP from other shrimp crustins. The differential expression of the crustinlike
AMP
in P. monodon in response to the administration of various immunostimulants viz., two marine yeasts
(Candida haemulonii S27 and Candida sake S165) and two bglucan
isolates (extracted from C. haemulonii
S27 and C. sake S165) were noted during the study. Responses to the application of two grampositive
probiotic bacteria (Bacillus MCCB101 and Micrococcus MCCB104) were also observed. The immune profile
was recorded preand
postchallenge
white spot syndrome virus (WSSV) by semiquantitative
RTPCR.
Expressions of seven WSSV genes were also observed for studying the intensity of viral infection in
the experimental animals. The crustinlike
AMP was found to be constitutively expressed in the animal
and a significant downregulation
could be noted postchallenge
WSSV. Remarkable downregulation
of the gene was observed in the immunostimulant fed animals prechallenge
followed by a significant
upregulation
postchallenge
WSSV. Tissuewise
expression of crustinlike
AMP on administration of C.
haemulonii and Bacillus showed maximum transcripts in gill and intestine. The marine yeast, C. haemulonii
and the probiotic bacteria, Bacillus were found to enhance the production of crustinlike
AMP and
confer significant protection to P. monodon against WSSV infection.
Rosamma, Philip; Preetha, R; Jayaprakash, N S; Bright Singh, I S(The Society for Applied Microbiology, 2007)
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Abstract:
Aim: To develop a new medium for enhanced production of biomass of an
aquaculture probiotic Pseudomonas MCCB 103 and its antagonistic phenazine
compound, pyocyanin.
Methods and Results: Carbon and nitrogen sources and growth factors, such as
amino acids and vitamins, were screened initially in a mineral medium for the
biomass and antagonistic compound of Pseudomonas MCCB 103. The selected
ingredients were further optimized using a full-factorial central composite
design of the response surface methodology. The medium optimized as per the
model for biomass contained mannitol (20 g l)1), glycerol (20 g l)1), sodium
chloride (5 g l)1), urea (3Æ3 g l)1) and mineral salts solution (20 ml l)1), and
the one optimized for the antagonistic compound contained mannitol (2 g l)1),
glycerol (20 g l)1), sodium chloride (5Æ1 g l)1), urea (3Æ6 g l)1) and mineral
salts solution (20 ml l)1). Subsequently, the model was validated experimentally
with a biomass increase by 19% and fivefold increase of the antagonistic
compound.
Conclusion: Significant increase in the biomass and antagonistic compound
production could be obtained in the new media.
Significance and Impact of the Study: Media formulation and optimization are
the primary steps involved in bioprocess technology, an attempt not made so
far in the production of aquaculture probiotics.
Rosamma, Philip; Preetha, R; Jayaprakash, N S; Bright Singh, I S(KSBB, 2007)
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Abstract:
A marine isolate of Micrococcus MCCB 104 has been identified as an aquaculture probiotic antagonistic to VIbrio. In the
present study different carbon and nitrogen sources and growth factors in a mineral base medium were optimized for enhanced
biomass production and antagonistic activity against the target pathogen, Vibrio harveyi, following response surface
methodology (RSM). Accordingly the minimum and maximum limits of the selected variables were determined and a set of
fifty experiments programmed employing central composite design (CCD) of RSM for the final optimization. The response
surface plots of biomass showed similar pattern with that of antagonistic activity, which indicated a strong correlation between
the biomass and antagonism. The optimum concentration of the carbon sources, nitrogen sources, and growth factors
for both biomass and antagonistic activity were glucose (17.4 g/L), lactose (17 g/L), sodium chloride (16.9 g/L),
ammonium chloride (3.3 g/L), and mineral salts solution (18.3 mL/L).