Optimization of β-Glucosidase Production by a Strain of Stereum hirsutum and Its Application in Enzymatic Saccharification

( Ramachandran priyadharshini ),( Ngoc Phuong Thao Nguyen ),( Joon Ho Choi ),( Yun Chan Kang ),( Marimuthu Jeya ),( Jung Kul Lee ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.3

A high β-glucosidase (BGL)-producing strain, Stereum hirsutum, was identified and isolated and showed a maximum BGL activity (10.4 U/ml) when cultured with Avicel and tryptone as the carbon and nitrogen sources, respectively. In comparison with other BGLs, BGL obtained from S. hirsutum showed a higher level of activity to cellobiose (Vmax = 172 U/mg, and kcat = 281/s). Under the optimum conditions (600 rpm, 30oC, and pH 6.0), the maximum BGL activity of 10.4 U/ml with the overall productivity of 74.5 U/l/h was observed. BGL production was scaled up from a laboratory scale (7-L fermenter) to a pilot scale (70-L fermenter). When S. hirsutum was cultured in fed-batch culture with rice straw as the carbon source in a 70-L fermenter, a comparable productivity of 78.6 U/l/h was obtained. Furthermore, S. hirsutum showed high levels of activity of other lignocellulases (cellobiohydrolase, endoglucanase, xylanase, and laccase) that are involved in the saccharification of biomasses. Application of S. hirsutum lignocellulases in the hydrolysis of Pinus densiflora and Catalpa ovata showed saccharification yields of 49.7% and 43.0%, respectively, which were higher than the yield obtained using commercial enzymes.

Greenhouse Evaluation and Inheritance Analysis of Transgenic Cotton Expressing PTM3, a MADS-Box Gene of Aspen

Ramachandran, Esakky,John, Suchit Ashish,Abraham, Gerard,Bhattacharya, Partha Sarathi 한국작물학회 2011 Journal of crop science and biotechnology Vol.14 No.4

The PTM3 (MADS-box) gene characterized from flower of Aspen was ectopically expressed in cotton and was found to result in desirable agronomic traits. Among several transgenic lines, the PTM3 cotton event-10 was found to flower significantly earlier than the control and yield better [Ramachandran et al. (2011)]. We report our findings on performance based on greenhouse evaluation and inheritance of PTM3 cotton event-10. The $T_1$ progeny of event-10 were grown in pots under RBD design. The progeny were confirmed by kanamycin imbibition test, PCR, and GUS assay which showed the segregation of transgene at about 3:1 ratio. GUS assay was performed with pollen from all transgenic plants; plants that expressed gus in all pollen versus those that showed segregation for expression were found to be at a ratio of 1:2. Similar to observations made in the $T_0$ generation of event-10, the agronomic evaluation of $T_1$ progeny exhibited, on an average, earliness of 13 days in flowering, 13.5 days in crop maturity, and 22% of yield enhancement. The $T_2$ progeny of homozygous lines were grown on field soil in the greenhouse under strip trial design to see the effect as observed from potted plants of $T_1$ progeny. Inheritance of transgene cassette to $T_2$ progeny was confirmed by the same tests used to analyze $T_1$ progeny. As exhibited by $T_0$ and $T_1$ progenies, the $T_2$ progeny also showed earliness of 8 days in flowering, 12 days in crop maturity, and 17% of yield enhancement. The data generated from the progeny over two generations confirms that the PTM3 cotton event-10 is superior in agronomic characters as compared to non-transgenic cotton and is of interest for breeding shorter duration varieties with improved yield.

Greenhouse Evaluation and Inheritance Analysis of Transgenic Cotton Expressing PTM3, a MADS-Box Gene of Aspen

Esakky Ramachandran,Suchit Ashish John,Gerard Abraham,Partha Sarathi Bhattacharya 한국작물학회 2011 Journal of crop science and biotechnology Vol.14 No.4

The PTM3 (MADS-box) gene characterized from flower of Aspen was ectopically expressed in cotton and was found to result in desirable agronomic traits. Among several transgenic lines, the PTM3 cotton event-10 was found to flower significantly earlier than the control and yield better [Ramachandran et al. (2011)]. We report our findings on performance based on greenhouse evaluation and inheritance of PTM3 cotton event-10. The T1 progeny of event-10 were grown in pots under RBD design. The progeny were confirmed by kanamycin imbibition test, PCR, and GUS assay which showed the segregation of transgene at about 3:1 ratio. GUS assay was performed with pollen from all transgenic plants; plants that expressed gus in all pollen versus those that showed segregation for expression were found to be at a ratio of 1:2. Similar to observations made in the T0 generation of event-10, the agronomic evaluation of T1 progeny exhibited, on an average, earliness of 13 days in flowering, 13.5 days in crop maturity, and 22% of yield enhancement. The T2 progeny of homozygous lines were grown on field soil in the greenhouse under strip trial design to see the effect as observed from potted plants of T1 progeny. Inheritance of transgene cassette to T2 progeny was confirmed by the same tests used to analyze T1progeny. As exhibited by T0 and T1 progenies, the T2 progeny also showed earliness of 8 days in flowering, 12 days in crop maturity,and 17% of yield enhancement. The data generated from the progeny over two generations confirms that the PTM3 cotton event-10is superior in agronomic characters as compared to non-transgenic cotton and is of interest for breeding shorter duration varieties with improved yield.

Chiral flat bands: Existence, engineering, and stability

Ramachandran, Ajith,Andreanov, Alexei,Flach, Sergej American Physical Society 2017 Physical Review B Vol.96 No.16

<P>We study flat bands in bipartite tight-binding networks with discrete translational invariance. Chiral flat bands with chiral symmetry eigenenergy E = 0 and host compact localized eigenstates for finite range hopping. For a bipartite network with a majority sublattice chiral flat bands emerge. We present a simple generating principle of chiral flat-band networks and as a showcase add to the previously observed cases a number of new potentially realizable chiral flat bands in various lattice dimensions. Chiral symmetry respecting network perturbations-including disorder and synthetic magnetic fields-preserve both the flat band and the modified compact localized states. Chiral flat bands are spectrally protected by gaps and pseudogaps in the presence of disorder due to Griffiths effects.</P>

Microstructure and corrosion behavior of electrodeposited nanocrystalline nickel prepared from acetate bath

Ramachandran Sekar,Kopula Kesavan Jagadesh,Giri Nagasamy Kuppusamy Ramesh Bapu 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.6

The present investigation deals with the electrodeposition of nanocrystalline nickel onto mild steel metallic foil from electrolytes containing nickel acetate as the major metal salt. Two different chlorides, potassium chloride and nickel chloride, were tried for two different baths. Potassium citrate was used as buffer for alternate to boric acid. The additives tried were sodium lauryl sulfate as wetting agent, saccharin as primary brightener and 2-butyne 1,4-diol as secondary brightener. These additives are found to improve the hardness, grain size, surface morphology of the electrodeposited nickel films and throwing power of the nickel acetate electrolytes. The nickel films prepared from nickel chloride containing electrolytes showed higher corrosion resistance as compared to potassium chloride containing electrolytes, because the nickel films produced from the nickel chloride electrolytes are compact and possess fine grained structure. The XRD pattern obtained for electrodeposited nickel shows polycrystalline face centered cubic structure. The crystal size was calculated using Scherrer formula. A uniform and pore free surface was observed under SEM analysis.

Isorhamnetin inhibits proliferation and invasion and induces apoptosis through the modulation of peroxisome proliferator-activated receptor 관 activation pathway in gastric cancer.

Ramachandran, Lalitha,Manu, Kanjoormana Aryan,Shanmugam, Muthu K,Li, Feng,Siveen, Kodappully Sivaraman,Vali, Shireen,Kapoor, Shweta,Abbasi, Taher,Surana, Rohit,Smoot, Duane T,Ashktorab, Hassan,Tan, Pa American Society for Biochemistry and Molecular Bi 2012 The Journal of biological chemistry Vol.287 No.45

<P>Gastric cancer (GC) is a lethal malignancy and the second most common cause of cancer-related deaths. Although treatment options such as chemotherapy, radiotherapy, and surgery have led to a decline in the mortality rate due to GC, chemoresistance remains as one of the major causes for poor prognosis and high recurrence rate. In this study, we investigated the potential effects of isorhamnetin (IH), a 3'-O-methylated metabolite of quercetin on the peroxisome proliferator-activated receptor 관 (PPAR-관) signaling cascade using proteomics technology platform, GC cell lines, and xenograft mice model. We observed that IH exerted a strong antiproliferative effect and increased cytotoxicity in combination with chemotherapeutic drugs. IH also inhibited the migratory/invasive properties of GC cells, which could be reversed in the presence of PPAR-관 inhibitor. We found that IH increased PPAR-관 activity and modulated the expression of PPAR-관 regulated genes in GC cells. Also, the increase in PPAR-관 activity was reversed in the presence of PPAR-관-specific inhibitor and a mutated PPAR-관 dominant negative plasmid, supporting our hypothesis that IH can act as a ligand of PPAR-관. Using molecular docking analysis, we demonstrate that IH formed interactions with seven polar residues and six nonpolar residues within the ligand-binding pocket of PPAR-관 that are reported to be critical for its activity and could competitively bind to PPAR-관. IH significantly increased the expression of PPAR-관 in tumor tissues obtained from xenograft model of GC. Overall, our findings clearly indicate that antitumor effects of IH may be mediated through modulation of the PPAR-관 activation pathway in GC.</P>

The Short-Lived Signaling State of the Photoactive Yellow Protein Photoreceptor Revealed by Combined Structural Probes

Ramachandran, Pradeep L.,Lovett, Janet E.,Carl, Patrick J.,Cammarata, Marco,Lee, Jae Hyuk,Jung, Yang Ouk,Ihee, Hyotcherl,Timmel, Christiane R.,van Thor, Jasper J. American Chemical Society 2011 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.133 No.24

<P>The signaling state of the photoactive yellow protein (PYP) photoreceptor is transiently developed via isomerization of its blue-light-absorbing chromophore. The associated structural rearrangements have large amplitude but, due to its transient nature and chemical exchange reactions that complicate NMR detection, its accurate three-dimensional structure in solution has been elusive. Here we report on direct structural observation of the transient signaling state by combining double electron electron resonance spectroscopy (DEER), NMR, and time-resolved pump–probe X-ray solution scattering (TR-SAXS/WAXS). Measurement of distance distributions for doubly spin-labeled photoreceptor constructs using DEER spectroscopy suggests that the signaling state is well ordered and shows that interspin-label distances change reversibly up to 19 Å upon illumination. The SAXS/WAXS difference signal for the signaling state relative to the ground state indicates the transient formation of an ordered and rearranged conformation, which has an increased radius of gyration, an increased maximum dimension, and a reduced excluded volume. Dynamical annealing calculations using the DEER derived long-range distance restraints in combination with short-range distance information from <SUP>1</SUP>H–<SUP>15</SUP>N HSQC perturbation spectroscopy give strong indication for a rearrangement that places part of the N-terminal domain in contact with the exposed chromophore binding cleft while the terminal residues extend away from the core. Time-resolved global structural information from pump–probe TR-SAXS/WAXS data supports this conformation and allows subsequent structural refinement that includes the combined energy terms from DEER, NMR, and SAXS/WAXS together. The resulting ensemble simultaneously satisfies all restraints, and the inclusion of TR-SAXS/WAXS effectively reduces the uncertainty arising from the possible spin-label orientations. The observations are essentially compatible with reduced folding of the I<SUB>2</SUB>′ state (also referred to as the ‘pB’ state) that is widely reported, but indicates it to be relatively ordered and rearranged. Furthermore, there is direct evidence for the repositioning of the N-terminal region in the I<SUB>2</SUB>′ state, which is structurally modeled by dynamical annealing and refinement calculations.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2011/jacsat.2011.133.issue-24/ja200617t/production/images/medium/ja-2011-00617t_0002.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja200617t'>ACS Electronic Supporting Info</A></P>

Lipid extraction from natural plant source of Adenanthera pavonina using mixed solvent by superheated extractor

Ramachandran Kasirajan,Renganathan Sahadevan,Sivakumar Pandian,Suganya Tamilarasan 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.3

The lipid content was extracted from the saga seed by superheated condition and soxhlet apparatus. Themixture of hexane, chloroform and methanol was utilized as a mixed solvent for these extraction operations. Differentparameters such as different solvent, temperature, mean particle size and solvent flow have been examined. The optimizedlipid extraction was achieved as 26.2 wt% by using superheated condition from the saga seed powder at 90 oCfor 120min. Then the fatty acids profile of the optimized Adenanthera pavonina oil were analyzed by gas chromatography. Unsaturated fatty acid was high as 83.7% compared with saturated fatty acid barely 15.4% by relative.

Stepwise Training for Reconstructive Microsurgery: The Journey to Becoming a Confident Microsurgeon in Singapore

Ramachandran, Savitha,Ong, Yee-Siang,Chin, Andrew Y.H.,Song, In-Chin,Ogden, Bryan,Tan, Bien-Keem Korean Society of Plastic and Reconstructive Surge 2014 Archives of Plastic Surgery Vol.41 No.3

Microsurgery training in Singapore began in 1980 with the opening of the Experimental Surgical Unit. Since then, the unit has continued to grow and have held microsurgical training courses biannually. The road to becoming a full-fledged reconstructive surgeon requires the mastering of both microvascular as well as flap raising techniques and requires time, patience and good training facilities. In Singapore, over the past 2 decades, we have had the opportunity to develop good training facilities and to refine our surgical education programmes in reconstructive microsurgery. In this article, we share our experience with training in reconstructive microsurgery.

Unveiling the Potentials of Bacteriocin (Pediocin L50) from Pediococcus acidilactici with Antagonist Spectrum in a Caenorhabditis elegans Model

Ramachandran Chelliah,Deog-Hwan Oh 한국식품영양과학회 2019 한국식품영양과학회 학술대회발표집 Vol.2019 No.10