I’m currently working in the Climate Change Cluster (C3) as an ARC DECRA Fellow. My work focuses on understanding seagrass responses to wide environmental fluctuations including light and eutrophication stress through functional genomic approaches. My doctoral thesis work broadly dealt with the critical aspects of eco-physiology, acclimation strategies and tolerance mechanisms at both biochemical and molecular level of benthic marine macrophytes (seaweeds and seagrasses) reeling under diverse environmental and anthropogenic stresses. My postdoctoral experience further expanded by expertise in transcriptomics and epigenitic regulation of marine and terrestrial plants under abiotic stress conditions at Ben-Gurion University (Israel).
Prior to joining UTS, I’ve worked as a Visiting Scientist for two years (2012-2014) at The Agriculture Research Organization (Israel) and focused on studying the Phyto-Hormone Signaling in plants in response to environmental stress.
2014 - ARC DECRA Fellowship (Early Detection of Seagrass Habitat Loss Caused by Eutrophication)
2013 - Outstanding ARO Postdoctoral Research Fellowship, Israel
2012 - Prestigious Blaustein Postdoctoral Fellowship, Israel
- New Phytologist
- Physiologia Plantarum
- Environmental and Experimental Botany
- Journal of Applied Phycology
- Marine Biology, Hazardous Materials
- Plant Physiology and Biochemistry
- Environmental Science and Pollution Research
Can supervise: YES
- Impacts of Global Climate Change (global warming, ocean acidification, environmental fluctuatuations, and Anthropogenic forces) on Eco-physiology of plants and marine macro algae (seaweeds): Understanding on acclimation and adaptive responses, reactive oxygen metabolism (ROM), and epigenetic regulations in marine macroalgae at biochemical and molecular level against adverse environmental and anthropogenically induced oxidative stress conditions such as salinity (hypo and -hyper), desiccation, heavy metal (copper and cadmium), industrial toxicants and eutorphication. (10 - Publications)
- Marker assisted selection, epigenetic regulations and phylogenetic studies of plants and algae. (4 - publications)
- Micropropagation of marine algae: Tissue culture, protoplast isolation and spore culture from marine seaweeds for their use as seed stock in mass culture and cultivation practices (3 - Publications)
- Bioethanol and phycolloids production from algae: Extraction and characterization of alkali tolerant cellulases (efficient in hydrolyzing macroalgal biomass) and sulfohydrolases from marine microbes associated with marine macroalgae. (4 - Publications)
- Nutritional and Pharmaceutical aspects of plants and algae: In search of species rich in antioxidant, minerals, plant growth regulators, infochemicals, nutrients and PUFAs. (3- Publications)
This book describes the latest advances in systems biology in four plant-based marine ecosystems: seaweeds, seagrasses, microalgae, and corals. Marine organisms that inhabit the oceanic environment experience a diverse range of environmental fluctuations, anthropogenic stress, and threats from invasive species and pathogens. System biology integrates physiology, genomics, transcriptomics, proteomics, and metabolomics into numerical models and is emerging as an important approach to elucidate the functional adaptations of marine organisms to adverse environmental conditions. This book focuses on how ecophysiology, omics platforms, their integration (a systems biology perspective), and next generation sequencing tools are being used to address the stress response of marine seaweeds, seagrasses, corals, marine microbe diversity, and micro-and macroalgae/corals-bacterial interactions to global climate change and anthropogenic activities. The contents of the book are of special interest to graduate and postgraduate marine biology students and marine biology researchers, particularly those interested in marine ecology, stress physiology of marine macrophytes/corals/phytoplankton, and environmental microbiology. This book would also be of interest to marine engineers engaged in the management and conservation of our valuable marine resources.
Kumar, M & Reddy, CRK 2012, Oxidative stress tolerance mechanisms in marine macroalgae (Seaweeds): Oxidative stress in seaweeds., LAP Lambert Academic Publishing.
Wu, S, Gu, W, Huang, A, Li, Y, Kumar, M, Lim, PE, Huan, L, Gao, S & Wang, G 2019, 'Elevated CO2 improves both lipid accumulation and growth rate in the glucose-6-phosphate dehydrogenase engineered Phaeodactylum tricornutum.', Microbial cell factories, vol. 18, no. 1.View/Download from: Publisher's site
BACKGROUND:Numerous studies have shown that stress induction and genetic engineering can effectively increase lipid accumulation, but lead to a decrease of growth in the majority of microalgae. We previously found that elevated CO2 concentration increased lipid productivity as well as growth in Phaeodactylum tricornutum, along with an enhancement of the oxidative pentose phosphate pathway (OPPP) activity. The purpose of this work directed toward the verification of the critical role of glucose-6-phosphate dehydrogenase (G6PDH), the rate-limiting enzyme in the OPPP, in lipid accumulation in P. tricornutum and its simultaneous rapid growth rate under high-CO2 (0.15%) cultivation. RESULTS:In this study, G6PDH was identified as a target for algal strain improvement, wherein G6PDH gene was successfully overexpressed and antisense knockdown in P. tricornutum, and systematic comparisons of the photosynthesis performance, algal growth, lipid content, fatty acid profiles, NADPH production, G6PDH activity and transcriptional abundance were performed. The results showed that, due to the enhanced G6PDH activity, transcriptional abundance and NAPDH production, overexpression of G6PDH accompanied by high-CO2 cultivation resulted in a much higher of both lipid content and growth in P. tricornutum, while knockdown of G6PDH greatly decreased algal growth as well as lipid accumulation. In addition, the total proportions of saturated and unsaturated fatty acid, especially the polyunsaturated fatty acid eicosapentaenoic acid (EPA; C20:5, n-3), were highly increased in high-CO2 cultivated G6PDH overexpressed strains. CONCLUSIONS:The successful of overexpression and antisense knockdown of G6PDH well demonstrated the positive influence of G6PDH on algal growth and lipid accumulation in P. tricornutum. The improvement of algal growth, lipid content as well as polyunsaturated fatty acids in high-CO2 cultivated G6PDH overexpressed P. tricornutum suggested this G6PDH overexpression-high CO...
Zapata, J, Meynard, A, Anguita, C, Espinoza, C, Alvear, P, Kumar, M & Contreras-Porcia, L 2019, 'Non-Random Distribution and Ecophysiological Differentiation of Pyropia Species (Bangiales, Rhodophyta) Through Environmental Gradients', Journal of Phycology, vol. 55, no. 5, pp. 1140-1153.View/Download from: Publisher's site
© 2019 Phycological Society of America Recently 18 Bangiales seaweed species were reported for the Chilean coast, including Pyropia orbicularis and Pyropia variabilis (large [LM] and green [GM] morphotypes). Porphyra/Pyropia spp. occur mainly in the upper intertidal where desiccation stress is triggered by tidal fluctuations. However, the influence of environmental and ecophysiological variables and seasonal differences on Porphyra/Pyropia (microhabitats) intertidal distributions is unknown. Accordingly, we determined (i) the effect of environmental variables (temperature [T], relative humidity [RH], and photosynthetically active radiation [PAR]) and season on distribution, and (ii) physiological (cellular activity and lipid peroxidation [LPX]) and molecular responses (antioxidant enzymes expression at biochemical and transcript level) to desiccation stress in both Pyropia species and morphotypes (common garden experiment, on flat rocky platforms). Multivariate analyses of coverage and abundance in relation to environmental variables revealed a significant effect of temperature on P. variabilis GM distribution, GM dominating almost exclusively on rocky walls (where lowest PAR and T values but maximum RH were registered). Conversely, Pyropia orbicularis and Pyropia variabilis LM were found in high abundance on flat rocky platforms in summer, LM and GM also dominating flat rocky platforms in winter and spring. LPX and catalase activity did not differed among species in summer, while in winter activity and transcription of cat were higher in P. orbicularis than P. variabilis. Results suggest that tolerance to environmental stresses such as temperature could regulate the occurrence of P. variabilis GM on rocky walls; conversely, abundances of P. variabilis and P. orbicularis on flat rocky platforms would be also regulated by other abiotic and/or biotic factors.
Buapet, P, Mohammadi, NS, Pernice, M, Kumar, M, Kuzhiumparambil, U & Ralph, PJ 2019, 'Excess copper promotes photoinhibition and modulates the expression of antioxidant-related genes in Zostera muelleri', AQUATIC TOXICOLOGY, vol. 207, pp. 91-100.View/Download from: Publisher's site
Jiang, Z, Liu, S, Zhang, J, Zhao, C, Wu, Y, Yu, S, Zhang, X, Huang, C, Huang, X & Kumar, M 2017, 'Newly discovered seagrass beds and their potential for blue carbon in the coastal seas of Hainan Island, South China Sea.', Marine Pollution Bulletin, vol. 125, no. 1-2, pp. 513-521.View/Download from: Publisher's site
Eight new seagrass beds were discovered along the coastline of Hainan Island in South China Sea with an area of 203.64ha. The leaf N content of all seagrasses was above the median value, indicative of N limitation, with their C:N ratio recorded significantly lower than the limiting criteria. This suggested that N is not limiting but in replete status. Further, the lower C content observed in the seagrass leaves was accompanied by higher nutrient concentration. The mean seagrass biomass C was 0.23±0.16MgCha-1, while the average sediment organic carbon (SOC) stock was 7.02±3.57MgCha-1. The entire SOC stock of the newly discovered seagrass beds was 1306.45 Mg C, and the overall SOC stock of seagrass bed at Hainan Island was 40858.5 Mg C. These seagrass beds are under constant threats from sea reclamation, nutrient input, aquaculture activities for oyster and snail farming, and fishing activities.
Jiang, Z, Kumar, M, Padula, MP, Pernice, M, Kahlke, T, Kim, M & Ralph, PJ 2017, 'Development of an Efficient Protein Extraction Method Compatible with LC-MS/MS for Proteome Mapping in Two Australian Seagrasses Zostera muelleri and Posidonia australis.', Frontiers in Plant Science, vol. 8, pp. 1-14.View/Download from: Publisher's site
The availability of the first complete genome sequence of the marine flowering plant Zostera marina (commonly known as seagrass) in early 2016, is expected to significantly raise the impact of seagrass proteomics. Seagrasses are marine ecosystem engineers that are currently declining worldwide at an alarming rate due to both natural and anthropogenic disturbances. Seagrasses (especially species of the genus Zostera) are compromised for proteomic studies primarily due to the lack of efficient protein extraction methods because of their recalcitrant cell wall which is rich in complex polysaccharides and a high abundance of secondary metabolites in their cells. In the present study, three protein extraction methods that are commonly used in plant proteomics i.e., phenol (P); trichloroacetic acid/acetone/SDS/phenol (TASP); and borax/polyvinyl-polypyrrolidone/phenol (BPP) extraction, were evaluated quantitatively and qualitatively based on two dimensional isoelectric focusing (2D-IEF) maps and LC-MS/MS analysis using the two most abundant Australian seagrass species, namely Zostera muelleri and Posidonia australis. All three tested methods produced high quality protein extracts with excellent 2D-IEF maps in P. australis. However, the BPP method produces better results in Z. muelleri compared to TASP and P. Therefore, we further modified the BPP method (M-BPP) by homogenizing the tissue in a modified protein extraction buffer containing both ionic and non-ionic detergents (0.5% SDS; 1.5% Triton X-100), 2% PVPP and protease inhibitors. Further, the extracted proteins were solubilized in 0.5% of zwitterionic detergent (C7BzO) instead of 4% CHAPS. This slight modification to the BPP method resulted in a higher protein yield, and good quality 2-DE maps with a higher number of protein spots in both the tested seagrasses. Further, the M-BPP method was successfully utilized in western-blot analysis of phosphoenolpyruvate carboxylase (PEPC-a key enzyme for carbon metabolism). ...
Kumar, M, Padula, MP, Davey, P, Pernice, M, Jiang, Z, Sablok, G, Contreras-Porcia, L & Ralph, PJ 2017, 'Proteome Analysis Reveals Extensive Light Stress-Response Reprogramming in the Seagrass Zostera muelleri (Alismatales, Zosteraceae) Metabolism.', Frontiers in Plant Science, vol. 7, pp. 1-19.View/Download from: Publisher's site
Seagrasses are marine ecosystem engineers that are currently declining in abundance at an alarming rate due to both natural and anthropogenic disturbances in ecological niches. Despite reports on the morphological and physiological adaptations of seagrasses to extreme environments, little is known of the molecular mechanisms underlying photo-acclimation, and/or tolerance in these marine plants. This study applies the two-dimensional isoelectric focusing (2D-IEF) proteomics approach to identify photo-acclimation/tolerance proteins in the marine seagrass Zostera muelleri. For this, Z. muelleri was exposed for 10 days in laboratory mesocosms to saturating (control, 200 μmol photons m-2 s-1), super-saturating (SSL, 600 μmol photons m-2 s-1), and limited light (LL, 20 μmol photons m-2 s-1) irradiance conditions. Using LC-MS/MS analysis, 93 and 40 protein spots were differentially regulated under SSL and LL conditions, respectively, when compared to the control. In contrast to the LL condition, Z. muelleri robustly tolerated super-saturation light than control conditions, evidenced by their higher relative maximum electron transport rate and minimum saturating irradiance values. Proteomic analyses revealed up-regulation and/or appearances of proteins belonging to the Calvin-Benson and Krebs cycle, glycolysis, the glycine cleavage system of photorespiration, and the antioxidant system. These proteins, together with those from the inter-connected glutamate-proline-GABA pathway, shaped Z. muelleri photosynthesis and growth under SSL conditions. In contrast, the LL condition negatively impacted the metabolic activities of Z. muelleri by down-regulating key metabolic enzymes for photosynthesis and the metabolism of carbohydrates and amino acids, which is consistent with the observation with lower photosynthetic performance under LL condition. This study provides novel insights into the underlying molecular photo-acclimation mechanisms in Z. muelleri, in addition to identify...
Kumar, M, Kuzhiumparambil, U, Pernice, M, Jiang, Z & Ralph, PJ 2016, 'Metabolomics: an emerging frontier of systems biology in marine macrophytes', ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS, vol. 16, pp. 76-92.View/Download from: Publisher's site
Kumar, M, Pandya-Kumar, N, Dam, A, Haor, H, Mayzlish-Gati, E, Belausov, E, Wininger, S, Abu-Abied, M, McErlean, CSP, Bromhead, LJ, Prandi, C, Kapulnik, Y & Koltai, H 2015, 'Arabidopsis response to low-phosphate conditions includes active changes in actin filaments and PIN2 polarization and is dependent on strigolactone signalling', Journal of Experimental Botany, vol. 66, no. 5, pp. 1499-1510.View/Download from: Publisher's site
Strigolactones (SLs) are plant hormones that regulate the plant response to phosphate (Pi) growth conditions. At least part of SL-signalling execution in roots involves MAX2-dependent effects on PIN2 polar localization in the plasma membrane (PM) and actin bundling and dynamics. We examined PIN2 expression, PIN2 PM localization, endosome trafficking, and actin bundling under low-Pi conditions: a MAX2-dependent reduction in PIN2 trafficking and polarization in the PM, reduced endosome trafficking, and increased actin-filament bundling were detected in root cells. The intracellular protein trafficking that is related to PIN proteins but unassociated with AUX1 PM localization was selectively inhibited. Exogenous supplementation of the synthetic SL GR24 to a SL-deficient mutant (max4) led to depletion of PIN2 from the PM under low-Pi conditions. Accordingly, roots of mutants in MAX2, MAX4, PIN2, TIR3, and ACTIN2 showed a reduced low-Pi response compared with the wild type, which could be restored by auxin (for all mutants) or GR24 (for all mutants except max2-1). Changes in PIN2 polarity, actin bundling, and vesicle trafficking may be involved in the response to low Pi in roots, dependent on SL/MAX2 signalling.
Kumar, M, Pandya-Kumar, N, Kapulnik, Y & Koltai, H 2015, 'Strigolactone signaling in root development and phosphate starvation', Plant Signaling and Behavior, vol. 10, no. 7.View/Download from: Publisher's site
Strigolactones (SLs), have recently been recognized as phytohormone involve in orchestrating shoot and root architecture. In, roots SLs positively regulate root hair length and density, suppress lateral root formation and promote primary root meristem cell number. The biosynthesis and exudation of SLs increases under low phosphate level to regulate root responses. This hormonal response suggests an adaptation strategy of plant to optimize growth and development under nutrient limitations. However, little is known on signal-transduction pathways associated with SL activities. In this review, we outline the current knowledge on SL biology by describing their role in the regulation of root development. Also, we discuss the recent findings on the non-cell autonomous signaling of SLs, that involve PIN polarization, vesicle trafficking, changes in actin architecture and dynamic in response to phosphate starvation.
Kumar, M, Reddy, CRK & Ralph, PJ 2015, 'Polyamines in morphogenesis and development: a promising research area in seaweeds.', Frontiers in plant science, vol. 6, pp. 27-27.View/Download from: Publisher's site
Flores-Molina, MR, Thomas, D, Lovazzano, C, Núñez, A, Zapata, J, Kumar, M, Correa, JA & Contreras-Porcia, L 2014, 'Desiccation stress in intertidal seaweeds: Effects on morphology, antioxidant responses and photosynthetic performance', Aquatic Botany, vol. 113, pp. 90-99.View/Download from: Publisher's site
Seaweeds are differentially distributed between the upper and lower limits of the intertidal zone of rocky coasts around the world. Daily changes in tide height cause water loss, triggering desiccation stress as a consequence. How this stress affected some of the morp hological characteristics and physiological responses in representative intertidal seaweeds with contrasting vertical distributions was explored in the present work. The selected species were Mazzaella laminarioides (upper-middle distribution), Scytosiphon lomentaria and Ulva compressa (middle distribution), and Lessonia spicata and Gelidium rex (lower distribution). To assess tolerance response to desiccation, cellular and morphological alterations, ROS production, enzymatic activity of catalase (CAT) and ascorbate peroxidase (AP) and photosynthesis performance were measured after a simulated emersion stress experiment. Results show different tolerance responses to desiccation, with seaweeds having higher intertidal distributions displaying greater antioxidant enzymatic activity, suggesting a higher capacity to buffer ROS excess induced during desiccation. Contrarily, this capacity seems to be absent or deficient in low intertidal species (i.e. L. spicata and G. rex), where AP and CAT activities were below detection limits, ROS were higher than normal and caused an over-oxidation of bio-molecules and photosynthetic disarray, explaining from a functional stand point their low distribution in the intertidal zone. © 2013 Elsevier B.V.
Kumar, M, Kumari, P, Reddy, CRK & Jha, B 2014, 'Salinity and Desiccation Induced Oxidative Stress Acclimation in Seaweeds', Advances in Botanical Research, vol. 71, pp. 91-123.View/Download from: Publisher's site
Marine macroalgae, commonly known as seaweeds, are assemblage of diverse groups of phototrophic marine plants and form the base of the marine trophic pyramid. Rocky intertidal zones are the most dynamic and comprises of highly stressful habitats for marine life including seaweeds. They often experience severe environmental stress as a result of periodic exposure to a wide range of ambient conditions including intense radiation, high temperature, desiccation and salinity with turning tides. The relative abundance, survivability and distribution of seaweeds in such environments are principally determined by their tolerance abilities to diverse environmental stresses. Any adverse effect on seaweeds as a result of fluctuating environmental conditions can directly or indirectly lead to perturbations at higher trophic levels and eventually affect the integrity and sustainability of aquatic ecosystems. The recent proteome, transcriptome, metabolome and other biochemical analysis of seaweeds under oxidative stress have suggested the involvement of mannitol, proline, abscisic acid, polyamines, polyunsaturated fatty acids, oxylipins and fatty acid desaturases among others defending the seaweeds from diverse environmental stress. Both salinity and desiccation stresses are comparable in the context of a reduction of cellular water potential but differ in physiological process of ions uptake and their ratio determines the acclimation potential of seaweeds. In this chapter, we describe various tolerance and adaptive strategies of seaweeds in response to salinity fluctuations and desiccation induced oxidative stress at both biochemical and molecular levels enabling them to endure successfully for extended periods of stresses. Further, the new opportunities that became available from whole genome sequences of the brown alga Ectocarpus siliculosus and the red alga Chondrus crispus, in gaining newer insights into the cellular mechanisms of stress tolerance at molecular level in se...
Kumari, P, Kumar, M, Reddy, CRK & Jha, B 2014, 'Nitrate and Phosphate Regimes Induced Lipidomic and Biochemical Changes in the Intertidal Macroalga Ulva lactuca (Ulvophyceae, Chlorophyta)', Plant and Cell Physiology, vol. 55, no. 1, pp. 52-63.View/Download from: Publisher's site
This study was carried out in order to understand the lipid and biochemical alterations resulting from different nutritional regimes of nitrate and phosphate in Ulva lactuca. The algal thalli cultured in artificial seawater (ASW) showed higher levels of carbohydrates and non-polar lipids and increased phosphatase activities, accompanied by degradation of polar lipids, proteins and pigments. Further, higher levels of lipid hydroperoxides indicated reative oxygen species (ROS)-mediated non-enzymatic lipid peroxidation due to nutritional limitation-induced oxidative stress. Those thalli cultured in ASW supplemented with nitrate showed responses corresponding to nitrate addition, such as an increase in pigments, monogalactosyldiacylglycerols, polyunsaturated fatty acids and nitrate reductase. In addition, these thalli showed partial induction of phosphatases, low phospholipids, and high sulfolipid and 1,2-diacylglyceryl-3-O-4'-(N,N,N-trimethyl)-homoserine (DGTS) due to phosphate limitation. Similarly, algal thalli cultured in ASW supplemented with phosphate showed down-regulation of phosphatases, an increase in phospholipids due to availability of phosphate as well as a decrease in nitrate reductase, pigment, monogalactosyldiacylglycerols and polyunsaturated fatty acids due to nitrate limitation. On the other hand, algal thalli cultured in ASW supplemented with both nitrate and phosphate showed recovery of lost pigments and proteins, a high monogalactosyldiacylglycerol/digalactosyldiacylglycerol ratio, high unsaturation and high oxylipin levels (both C18 and C20). Further, the accumulation of indole-3-acetic acid in nutrient-limited thalli and of kinetin and kinetin riboside in nutrient-supplemented thalli indicated their antagonistic roles under nutrient stress. Thus, U. lactuca copes with nitrate and phosphate nutritional stress by altering the metabolic pathways involved in lipid biosynthesis including a shift in lipid classes, fatty acids, oxylipins and indole-3-...
Pandya-Kumar, N, Shema, R, Kumar, M, Mayzlish-Gati, E, Levy, D, Zemach, H, Belausov, E, Wininger, S, Abu-Abied, M, Kapulnik, Y & Koltai, H 2014, 'Strigolactone analog GR24 triggers changes in PIN2 polarity, vesicle trafficking and actin filament architecture', New Phytologist, vol. 202, no. 4, pp. 1184-1196.View/Download from: Publisher's site
SummaryStrigolactones (SLs) are plant hormones that regulate shoot and root development in aMAX2-dependent manner. The mechanism underlying SLs' effects on roots is unclear.We used root hair elongation to measure root response to SLs. We examined the effects ofGR24 (a synthetic, biologically active SL analog) on localization of the auxin efflux transporterPIN2, endosomal trafficking, and F-actin architecture and dynamics in the plasma membrane(PM) of epidermal cells of the primary root elongation zone in wildtype (WT) Arabidopsis andthe SL-insensitive mutant max2. We also recorded the response to GR24 of trafficking (tir3),actin (der1) and PIN2 (eir1) mutants.GR24 increased polar localization of PIN2 in the PM of epidermal cells and accumulation ofPIN2-containing brefeldin A (BFA) bodies, increased ARA7-labeled endosomal trafficking,reduced F-actin bundling and enhanced actin dynamics, all in a MAX2-dependent manner.Most of the der1 and tir3 mutant lines also displayed reduced sensitivity to GR24 with respectto root hair elongation.We suggest that SLs increase PIN2 polar localization, PIN2 endocytosis, endosomal traffick-ing, actin debundling and actin dynamics in a MAX2-dependent fashion. This enhancementmight underlie the WT root's response to SLs, and suggests noncell autonomous activity ofSLs in roots
Gupta, V, Trivedi, N, Kumar, M, Reddy, CRK & Jha, B 2013, 'Purification and characterization of exo-beta-agarase from an endophytic marine bacterium and its catalytic potential in bioconversion of red algal cell wall polysaccharides into galactans', BIOMASS & BIOENERGY, vol. 49, pp. 290-298.View/Download from: Publisher's site
Kumar, M, Reddy, CRK & Jha, B 2013, 'The ameliorating effect of Acadian marine plant extract against ionic liquids-induced oxidative stress and DNA damage in marine macroalga Ulva lactuca.', Journal of Applied Phycology, vol. 25, no. 2, pp. 369-378.View/Download from: Publisher's site
Ionic liquids (ILs) are generally considered as the green replacement for conventional volatile organic solvents. Nonetheless, their high solubility in water with proven toxic effects on aquatic biota has questioned their green credentials. In the present study, the detoxification potential of Acadian marine plant extract powder (AMPEP) prepared from the brown alga Ascophyllum nodosum was investigated against the 1-alkyl-3-methylimidazolium bromide [C12mim]Br ionic liquid-induced toxicity and oxidative stress in marine macroalga Ulva lactuca. The IL ([C12mim]Br) at LC50 (70 μM) exposure triggered the generation of reactive oxygen species (ROS) such as O 2 ·− , H2O2 and OH· causing membrane and DNA damage together with inhibition of antioxidant systems in the alga. The supplementation of AMPEP (150 μg mL−1) to the culture medium significantly reduced the accumulation of ROS and lipid peroxidation together with the inhibition of lipoxygenase (LOX) activity specially LOX-2 and LOX-3 isoforms. This is for the first time wherein comet assay was performed to ascertain the protective role of AMPEP against DNA damage in algal tissue grown in medium supplemented with IL and AMPEP. The AMPEP showed protective role against DNA damage (5–45 % tail DNA) when compared to those of grown in IL alone (45–70 % tail DNA). Further, specific isomorphs of different antioxidant enzymes such as superoxide dismutase (Mn-SOD-1, ~150 kDa), ascorbate peroxidase (APX-4, ~55 kDa), glutathione peroxidase (GSH-Px-2, ~55 kDa) and glutathione reductase (GR-1, ~180 kDa) responded specifically to AMPEP supplementation. It is evident from these findings that AMPEP could possibly be used for circumventing the negative effects arising from ILs-induced toxicity in marine ecosystem.
Gupta, V, Bijo, AJ, Kumar, M, Reddy, CRK & Jha, B 2012, 'Detection of Epigenetic Variations in the Protoplast-Derived Germlings of Ulva reticulata Using Methylation Sensitive Amplification Polymorphism (MSAP)', MARINE BIOTECHNOLOGY, vol. 14, no. 6, pp. 692-700.View/Download from: Publisher's site
Kumar, M, Bijo, AJ, Baghel, RS, Reddy, CRK & Jha, B 2012, 'Selenium and spermine alleviate cadmium induced toxicity in the red seaweed Gracilaria dura by regulating antioxidants and DNA methylation', Plant Physiol Biochem., vol. 51, pp. 129-138.View/Download from: Publisher's site
The protective role of exogenously supplied selenium (Se) and polyamines (PAs) such as putrescine (Put) and spermine (Spm) in detoxifying the cadmium (Cd) induced toxicity was studied in the marine red alga Gracilaria dura in laboratory conditions. The Cd exposure (0.4 mM) impede the growth of alga while triggering the reactive oxygen species (ROS viz. O2•− and H2O2) generation, inhibition of antioxidant system, and enhancing the lipoxygenase (LOX) activity, malondialdehyde (MDA) level and demethylation of DNA. Additions of Se (50 μM) and/or Spm (1 mM) to the culture medium in contrast to Put, efficiently ameliorated the Cd toxicity by decreasing the accumulation of ROS and MDA contents, while restoring or enhancing the level of enzymatic and nonenzymatic antioxidants and their redox ratio, phycobiliproteins and phytochelatins, over the controls. The isoforms of antioxidant enzymes namely superoxide dismutase (Mn-SOD, ∼ 150 kDa; Fe-SOD ∼120 kDa), glutathione peroxidase (GSH-Px, ∼120 and 140 kDa), glutathione reductase (GR, ∼110 kDa) regulated differentially to Se and/or Spm supplementation. Furthermore, it has also resulted in enhanced levels of endogenous PAs (specially free and bound insoluble Put and Spm) and n-6 PUFAs (C20-3, n-6 and C20-4, n-6). This is for the first time wherein Se and Spm were found to regulate the stabilization of DNA methylation by reducing the events of cytosine demethylation in a mechanism to alleviate the Cd stress in marine alga. The present findings reveal that both Se and Spm play a crucial role in controlling the Cd induced oxidative stress in G. dura.
Gupta, V, Baghel, RS, Kumar, M, Kumari, P, Mantri, VA, Reddy, CRK & Jha, B 2011, 'Growth and agarose characteristics of isomorphic gametophyte (male and female) and sporophyte of Gracilaria dura and their marker assisted selection', AQUACULTURE, vol. 318, no. 3-4, pp. 389-396.View/Download from: Publisher's site
Gupta, V, Kumar, M, Brahmbhatt, H, Reddy, CRK, Seth, A & Jha, B 2011, 'Simultaneous determination of different endogenetic plant growth regulators in common green seaweeds using dispersive liquid-liquid microextraction method', PLANT PHYSIOLOGY AND BIOCHEMISTRY, vol. 49, no. 11, pp. 1259-1263.View/Download from: Publisher's site
Gupta, V, Kumar, M, Kumari, P, Reddy, CRK & Jha, B 2011, 'Optimization of protoplast yields from the red algae Gracilaria dura (C. Agardh) J. Agardh and G. verrucosa (Huds.) Papenfuss', JOURNAL OF APPLIED PHYCOLOGY, vol. 23, no. 2, pp. 209-218.View/Download from: Publisher's site
Khan, N-UH, Pandya, N, Maity, NC, Kumar, M, Patel, RM, Kureshy, RI, Abdi, SHR, Mishra, S, Das, S & Bajaj, HC 2011, 'Influence of chirality of V(V) Schiff base complexes on DNA, BSA binding and cleavage activity', EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY, vol. 46, no. 10, pp. 5074-5085.View/Download from: Publisher's site
Kumar, M, Gupta, V, Trivedi, N, Kumari, P, Bijo, AJ, Reddy, CRK & Jha, B 2011, 'Desiccation induced oxidative stress and its biochemical responses in intertidal red alga Gracilaria corticata (Gracilariales, Rhodophyta)', ENVIRONMENTAL AND EXPERIMENTAL BOTANY, vol. 72, no. 2, pp. 194-201.View/Download from: Publisher's site
Kumar, M, Kumari, P, Trivedi, N, Shukla, MK, Gupta, V, Reddy, CRK & Jha, B 2011, 'Minerals, PUFAs and antioxidant properties of some tropical seaweed from Saurashtra coast of India', Journal of Applied Phycology, vol. 23, no. 5, pp. 797-810.View/Download from: Publisher's site
Twenty-two tropical seaweeds from the Rhodophyta, Phaeophyta and Chlorophyta were examined for their possible use as nutritional supplements. All seaweeds contained balanced Na/K and C/N ratio and high amounts of macroelements (Na, K, Ca, and Mg) as compared to the terrestrial vegetables. Among the microelements, Fe was the highest followed by Zn, Mn, Cu and other trace elements. Fatty acid distribution showed high level of n-6 and n-3 polyunsaturated fatty acids (PUFAs), and their ratios were within the WHO prescribed limits. The higher ratios of PUFA/SFA (>0.4) are in agreement with the recommendations of nutritional guidelines. Most of the species, especially the Chlorophyta and Phaeophyta, had permissible intake values of unsaturation, atherogenic and thrombogenic indexes comparable to milk-based products. Principal component analysis demonstrated a correlation between total phenolic content, total antioxidant activity, DPPH, and O 2 •− radical scavenging activity, suggesting polyphenols as the chief contributor to the antioxidant activity in seaweeds. These results indicate that these seaweeds could be a potential source of natural antioxidants, minerals and high-quality PUFAs and may be efficiently used as ingredients in functional foods.
Kumar, M, Trivedi, N, Reddy, CRK & Jha, B 2011, 'Toxic Effects of Imidazolium Ionic Liquids on the Green Seaweed Ulva lactuca: Oxidative Stress and DNA Damage', CHEMICAL RESEARCH IN TOXICOLOGY, vol. 24, no. 11, pp. 1882-1890.View/Download from: Publisher's site
Shukla, MK, Kumar, M, Prasad, K, Reddy, CRK & Jha, B 2011, 'Partial characterization of sulfohydrolase from Gracilaria dura and evaluation of its potential application in improvement of the agar quality', CARBOHYDRATE POLYMERS, vol. 85, no. 1, pp. 157-163.View/Download from: Publisher's site
Singh, RP, Gupta, V, Kumari, P, Kumar, M, Reddy, CRK, Prasad, K & Jha, B 2011, 'Purification and partial characterization of an extracellular alginate lyase from Aspergillus oryzae isolated from brown seaweed', JOURNAL OF APPLIED PHYCOLOGY, vol. 23, no. 4, pp. 755-762.View/Download from: Publisher's site
Trivedi, N, Gupta, V, Kumar, M, Kumari, P, Reddy, CRK & Jha, B 2011, 'An alkali-halotolerant cellulose from Bacillus flexus isolated from green seaweed Ulva lactuca.', Carbohydrate Polymers, vol. 83, no. 2, pp. 891-897.View/Download from: Publisher's site
An extracellular alkali-halotolerant cellulase from the strain Bacillus flexus NT isolated from Ulva lactuca was purified to homogeneity with a recovery of 25.03% and purity fold of 22.31. The molecular weight of the enzyme was about 97 kDa and the Vmax and Km was 370.17 U/ml/min and 6.18 mg/ml respectively. The optimum pH and temperature for enzyme activity was 10 and 45 °C respectively. The enzymatic hydrolysis of the CMC was confirmed with GPC and GC-MS analysis. The stabilized activity of the enzyme even at high pH of 9.0–12.0 and residual activity of about 70% at salt concentration (NaCl 15%) revealed for its alkali-halotolerance nature. The metal ions Cd2+ and Li1+ were found as inducers while Cr2+, Co2+, Zn2+ and metal chelator EDTA have significantly inhibited the enzyme activity. Enzyme activity was insensitive to ethanol and isopropanol while partially inhibited by acetone, cyclohexane and benzene.
Trivedi, N, Gupta, V, Kumar, M, Kumari, P, Reddy, CRK & Jha, B 2011, 'Solvent tolerant marine bacterium Bacillus aquimaris secreting organic solvent stable alkaline cellulase', CHEMOSPHERE, vol. 83, no. 5, pp. 706-712.View/Download from: Publisher's site
Khan, N-UH, Pandya, N, Kumar, M, Bera, PK, Kureshy, RI, Abdi, SHR & Bajaj, HC 2010, 'Influence of chirality using Mn(III) salen complexes on DNA binding and antioxidant activity', ORGANIC & BIOMOLECULAR CHEMISTRY, vol. 8, no. 19, pp. 4297-4307.View/Download from: Publisher's site
Kumar, M, Gupta, V, Kumari, P & Reddy, CRK 2010, 'Assesment of nutrient composition and antioxidant potential of seaweeds from Caulerpaceae.', Journal of Food Composition and Analysis, vol. 24, no. 2, pp. 270-278.View/Download from: Publisher's site
The proximate nutrient composition, mineral contents, enzymatic and non-enzymatic antioxidant potential of three Caulerpa species were investigated. All three species were high in ash (24.20–33.70%) and carbohydrate content (37.23–48.95%) on dry weight basis (DW). The lipid content ranged between 2.64 and 3.06% DW. The mineral contents varied marginally among the species but were in the order of Na > K > Ca > Mg. The Na/K ratio among the species varied from 1.80 to 2.55 and was lowest in C. scalpelliformis. A 10 g DW of Caulerpa powder contains 11–21% Fe, 52–60% Ca and 35–43% Mg, which is higher than the recommended daily allowance (RDA), compared with non-seafood. The percentage sum of PUFAs (C18:2, C18:3, C20:4 and C20:5) in total fatty acids was highest in both C. scalpelliformis (39.25%) and C. veravelensis (36.73%) while it was the lowest in C. racemosa (24.50%). The n−6/n−3 ratio among the species varied from 1.44 to 7.72 and remained within the prescribed WHO standards (<10). Further, the higher enzymatic dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) and non-enzymatic antioxidant potential of Caulerpa species found in the present study confirm their usefulness in terms of nutrients and antioxidants.
Kumar, M, Kumari, P, Gupta, V, Anisha, PA, Reddy, CRK & Jha, B 2010, 'Differential responses to cadmium induced oxidative stress in marine macroalga Ulva lactuca (Ulvales, Chlorophyta)', BIOMETALS, vol. 23, no. 2, pp. 315-325.View/Download from: Publisher's site
Kumar, M, Kumari, P, Gupta, V, Reddy, CRK & Jha, B 2010, 'Biochemical responses of red alga Gracilaria corticata (Gracilariales, Rhodophyta) to salinity induced oxidative stress', JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY, vol. 391, no. 1-2, pp. 27-34.View/Download from: Publisher's site
Kumari, P, Kumar, M, Gupta, V, Reddy, CRK & Jha, B 2010, 'Tropical marine macroalgae as potential sources of nutritionally important PUFAs', FOOD CHEMISTRY, vol. 120, no. 3, pp. 749-757.View/Download from: Publisher's site
Mantri, VA, Thakur, MC, Kumar, M, Reddy, CRK & Jha, B 2009, 'The carpospore culture of industrially important red alga Gracilaria dura (Gracilariales, Rhodophyta)', AQUACULTURE, vol. 297, no. 1-4, pp. 85-90.View/Download from: Publisher's site
Reddy, CRK, Gupta, MK, Mantri, VA & Jha, B 2008, 'Seaweed protoplasts: status, biotechnological perspectives and needs', JOURNAL OF APPLIED PHYCOLOGY, vol. 20, no. 5, pp. 619-632.View/Download from: Publisher's site
Kumar, M, Contreras-Porcia, L, Kumar, NM & Ralph, PJ 2018, 'Quantification and localization of reactive oxygen species in marine macrophytes' in Protocols for Macroalgae Research, CRC Press, pp. 267-277.View/Download from: Publisher's site
Contreras-Porcia, L, López-Cristoffanini, C, Meynard, A & Kumar, M 2017, 'Tolerance pathways to desiccation stress in seaweeds' in Systems Biology of Marine Ecosystems, pp. 13-33.View/Download from: Publisher's site
© Springer International Publishing AG 2017. Seaweeds are sessile organisms that inhabit coastal benthic systems and are key species for the equilibrium of marine communities. Rocky intertidal zone seaweeds are distributed in marked patterns determined by interactions between biotic and abiotic factors influenced by tide levels. It has been proposed that the distribution and abundance of organisms in the upper intertidal zones, with longer emersions, are mostly regulated by abiotic factors. Desiccation is a particularly noteworthy abiotic factor since, during low tide, algae of the upper intertidal zones can lose more than 90% of cellular water content, which can ultimately induce oxidative stress. Considering the necessary activation of several desiccation tolerance mechanisms, these algal species are ideal research models in ecophysiology. In fact, several studies using physiological, transcriptomic, and proteomic approaches have determined that desiccation tolerance mechanisms are expressed within a well-coordinated network that includes morphological and cell wall changes, photosynthetic activity diminishment, increased expression of desiccation-associated proteins, hormone accumulation, ROS scavenging by antioxidant enzymes and compounds, and osmolyte and protein synthesis. These mechanisms explain the permanence of tolerant algae species in the upper intertidal zone in comparison with lower intertidal species. Therefore, this chapter focuses on identifying tolerant algal species, and explaining the mechanisms underlying the high capacity of these species to cope with desiccation- induced oxidative stress.
Contreras-Porcia, L, Meynard, A, López-Cristoffanini, C, Latorre, N & Kumar, M 2017, 'Marine metal pollution and effects on seaweed species' in Systems Biology of Marine Ecosystems, pp. 35-48.View/Download from: Publisher's site
© Springer International Publishing AG 2017. Heavy metals are significant pollutants continuously released into the biosphere, both naturally and anthropogenically. Conceptually, metal speciation, bioavailability, and associated toxicity in marine organisms depend on a wide array of abiotic and biotic factors. Among these, pH variation is one of the most important environmental factors influencing metal speciation and toxicity. Due to this, ocean acidification is expected to modify metal speciation, altering the effects these nondegradable contaminants have on marine organisms, such as seaweeds. One clear effect of heavy metals on seaweeds is the rapid formation of reactive oxygen species (ROS). The production of ROS beyond the physiological tolerance threshold causes an oxidative stress condition that, if not attenuated, can irreversibly damage cellular constituents such as DNA/RNA, proteins, and lipids. To cope with heavy metal excess, several mechanisms exist in tolerant seaweed species, including the activation of an efficient ROS-scavenging system constituted by metal-binding compounds, antioxidant enzymes, and oxygenated polyunsaturated fatty acids, among others. Another adaptive mechanism involves the participation of ATP-binding cassette (ABC) transporter proteins in translocating a wide variety of compounds across cell membranes, including heavy metals. In contrast, an excessive heavy metal presence can inhibit photosynthesis, reduce pigment concentration and growth, induce cation losses, and disrupt gametophyte development in non-tolerant seaweed species. In a scenario of lowered ocean pH and increased heavy metal toxicity, the important roles played by non-tolerant seaweed species in structuring communities could be severely compromised, with unknown consequences for associated organisms. Therefore, in the upcoming decades, marine pollution could majorly shift and rearrange community compositions and the distributional ranges of species.
Kumar, M, Ralph, P & Kuzhiumparambil, U 2017, 'Polyamines-stress metabolites in marine macrophytes' in ALGAL GREEN CHEMISTRY: RECENT PROGRESS IN BIOTECHNOLOGY, Elsevier.View/Download from: Publisher's site
Kuzhiumparambil, U, Kumar, M & Ralph, P 2017, 'Gas and liquid chromatography-mass spectrometry-based metabolic profiling of marine angiosperm Zostera Muelleri (alismatales, zosteraceae)' in Systems Biology of Marine Ecosystems, pp. 189-203.View/Download from: Publisher's site
© Springer International Publishing AG 2017. Seagrasses are monocotyledonous marine flowering plants that are considered lungs of the sea and are the most intense carbon sinks on the planet, delivering a range of ecologically and economically valuable biological services. In this study, we report the chemical fingerprint of Zostera muelleri using an untargeted metabolomic approach. High-performance liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS) were performed to study the metabolic profile of Z. muelleri. A total of 98 metabolites belonging to various chemical classes including flavonoids, phenolics, lipids, fatty acids, sugar alcohols and amino acids were identified, including two characteristic marker compounds of the genus, zosteric acid and rosmarinic acid. Chromatographic profiling yield a comprehensive map for the chemical constituents of Z. muelleri, and this method can be used as an effective and convenient approach to gain insights into the chemical composition of other seagrasses.
Kumari, P, Kumar, M, Reddy, CRK & Jha, B 2013, 'Algal lipids, fatty acids and sterols' in Functional Ingredients from Algae for Foods and Nutraceuticals, Woodhead Publishing Limited, USA, pp. 87-134.View/Download from: Publisher's site
Algae are photosynthetic organisms with ubiquitous distribution and contain varied forms of lipids owing to their extreme habitat diversity. This chapter presents detailed information on the structure and distribution of lipids, fatty acids and sterols in algae together with the genes and enzymes involved in their metabolism. The developments in acclimatory roles of lipids, fatty acids and sterols in response to changes in environmental factors such as nutrients, light, temperature and salinity have been discussed. Further, the current status of lipidomics in algae has also been discussed presuming its promising implications in elucidation of novel lipids and understanding of complex metabolic pathways. © 2013 Woodhead Publishing Limited All rights reserved.