Phenotypic niche partitioning and transcriptional responses of <i>Microcystis aeruginosa</i> in a spatially heterogeneous environment

Srivastava, Ankita,Jeong, Haeyoung,Ko, So-Ra,Ahn, Chi-Yong,Choi, Ji Won,Park, Yong Il,Neilan, Brett Anthony,Oh, Hee-Mock Elsevier 2019 Algal research Vol.41 No.-

<P><B>Abstract</B></P> <P>Variant morphotypes (smooth; S-type and wrinkled; W-type cells) of <I>Microcystis aeruginosa</I> KW strain were observed in bloom samples and during the cultivation of cells in static broth cultures. RNA-seq based whole transcriptome sequencing was performed to examine the pattern of gene expression in these morphotypes. In total 493 differentially expressed transcripts were identified between the two morphotypes. Genes involved in photosynthesis, photosynthesis-related antenna proteins and oxidative phosphorylation were significantly upregulated in W-type cells relative to the control (S-type cells). Here we discussed the roles of these genes and showed that <I>M. aeruginosa</I> responds and acclimates to subtle variations in environmental parameters, especially light, through alteration of the transcript levels of relevant genes. Furthermore, additional physiological experiments such as analyses of photosynthetic activity, redox state and exopolysaccharide production provided further evidence and confirmed the validity of the transcriptomic results. The findings of this study provide greater insight into the metabolic pathways and complex mechanisms that may regulate the interaction and niche adaptation of this important bloom-forming organism in fluctuating environmental conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Microcystis</I> showed phenotypic plasticity (smooth; S, wrinkle; W) in lab cultivation. </LI> <LI> <I>M</I>orphotypes: W-type cells float; S-type cells sink during static cultivation. </LI> <LI> Basis of <I>Microcystis</I> phenotypic plasticity was analyzed by transcriptomics. </LI> <LI> Energy and oxidative phosphorylation-related transcripts increased in W-type cells. </LI> <LI> Carbohydrate metabolism-related transcripts decreased in W-type cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Floating rice-culture system for nutrient remediation and feed production in a eutrophic lake

Srivastava, Ankita,Chun, Seong-Jun,Ko, So-Ra,Kim, Junhwan,Ahn, Chi-Yong,Oh, Hee-Mock Elsevier 2017 Journal of environmental management Vol.203 No.1

<P>The increased inputs of nutrients have been demonstrated to be a major contributing factor to the eutrophication of lakes and reservoirs which can lead to the production of harmful algal/cyanobacterial blooms and deleteriously affect the aesthetics of water-bodies. Floating plant-culture systems have been widely used for the ecological remediation of eutrophic water in a cost-effective manner. We investigated the applicability of Korean japonica rice variety 'Nampyeong' in a floating-culture system in a eutrophic lake for nutrient uptake and biomass production. Chemical and organic compound compositions were analyzed two times during the growth stages of the rice plant: 98 DAT (days after transplanting) and 165 DAT. Total nitrogen and phosphorus contributed around 1.36 and 0.15 (% dry weight), respectively, in rice plant components at 165 DAT. Crude protein, lipids, fiber and ash were 4.35, 1.91, 23.66 and 5.55 (% dry weight), respectively. In addition, microcystin levels in the rice plant components ranged from 0.0008 to 0.002 gig and did not exceed the recommended tolerable limits. These results suggested that the developed floating rice-culture system showed a good potential as a holistic management approach in terms of nutrient reduction, rice production for further use as feed and for bloom control. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Status, Alert System, and Prediction of Cyanobacterial Bloom in South Korea

Srivastava, Ankita,Ahn, Chi-Yong,Asthana, Ravi Kumar,Lee, Hyung-Gwan,Oh, Hee-Mock Hindawi Publishing Corporation 2015 BioMed research international Vol.2015 No.-

<P>Bloom-forming freshwater cyanobacterial genera pose a major ecological problem due to their ability to produce toxins and other bioactive compounds, which can have important implications in illnesses of humans and livestock. Cyanobacteria such as <I>Microcystis, Anabaena, Oscillatoria, Phormidium</I>, and <I>Aphanizomenon</I> species producing microcystins and anatoxin-a have been predominantly documented from most South Korean lakes and reservoirs. With the increase in frequency of such blooms, various monitoring approaches, treatment processes, and prediction models have been developed in due course. In this paper we review the field studies and current knowledge on toxin producing cyanobacterial species and ecological variables that regulate toxin production and bloom formation in major rivers (Han, Geum, Nakdong, and Yeongsan) and reservoirs in South Korea. In addition, development of new, fast, and high-throughput techniques for effective monitoring is also discussed with cyanobacterial bloom advisory practices, current management strategies, and their implications in South Korean freshwater bodies.</P>

Microcystin Biosynthesis and <i> mcyA</i> Expression in Geographically Distinct <i> Microcystis</i> Strains under Different Nitrogen, Phosphorus, and Boron Regimes

Srivastava, Ankita,Ko, So-Ra,Ahn, Chi-Yong,Oh, Hee-Mock,Ravi, Alok Kumar,Asthana, Ravi Kumar Hindawi Publishing Corporation 2016 BioMed research international Vol.2016 No.-

<P>Roles of nutrients and other environmental variables in development of cyanobacterial bloom and its toxicity are complex and not well understood. We have monitored the photoautotrophic growth, total microcystin concentration, and microcystins synthetase gene (<I>mcyA</I>) expression in lab-grown strains of<I> Microcystis</I> NIES 843 (reference strain), KW (Wangsong Reservoir, South Korea), and Durgakund (Varanasi, India) under different nutrient regimes (nitrogen, phosphorus, and boron). Higher level of nitrogen and boron resulted in increased growth (avg. 5 and 6.5 Chl <I>a</I> mg/L, resp.), total microcystin concentrations (avg. 1.185 and 7.153 mg/L, resp.), and<I> mcyA</I> transcript but its expression was not directly correlated with total microcystin concentrations in the target strains. Interestingly, Durgakund strain had much lower microcystin content and lacked microcystin-YR variant over NIES 843 and KW. It is inferred that microcystin concentration and its variants are strain specific. We have also examined the heterotrophic bacteria associated with cyanobacterial bloom in Durgakund Pond and Wangsong Reservoir which were found to be enriched in Alpha-, Beta-, and Gammaproteobacteria and that could influence the bloom dynamics.</P>

Bioflocculation in natural and engineered systems: current perspectives

Srivastava, Ankita,Seo, Seong-Hyun,Ko, So-Ra,Ahn, Chi-Yong,Oh, Hee-Mock Informa UK (TaylorFrancis) 2018 Critical reviews in biotechnology Vol.38 No.8

Monitoring Approaches for a Toxic Cyanobacterial Bloom

Srivastava, Ankita,Singh, Shweta,Ahn, Chi-Yong,Oh, Hee-Mock,Asthana, Ravi Kumar American Chemical Society 2013 Environmental science & technology Vol.47 No.16

<P>Cyanobacterial blooms, dominated by <I>Microcystis</I> sp. and associated microcystin variants, have been implicated in illnesses of humans and animals. Little is known regarding the formation of blooms and the presence of cyanotoxin variants in water bodies. Furthermore, the role played by ecological parameters, in regulating <I>Microcystis</I> blooms is complicate and diverse. Local authorities responsible for water management are often faced with the challenging task of dealing with cyanobacterial blooms. Therefore, the development of suitable monitoring approaches to characterize cyanobacterial blooms is an important goal. Currently, various biological, biochemical and physicochemical methods/approaches are being used to monitor cyanobacterial blooms and detect microcystins in freshwater bodies. Because these methods can vary as to the information they provide, no single approach seemed to be sufficient to accurately monitor blooms. For example, immunosensors are more suited for monitoring the presence of toxins in clear water bodies while molecular methods are more suited to detect potentially toxic strains. Thus, monitoring approaches should be tailored for specific water bodies using methods based on economic feasibility, speed, sensitivity and field applicability. This review critically evaluates monitoring approaches that are applicable to cyanobacterial blooms, especially those that focus on the presence of <I>Microcystis</I>, in freshwater bodies. Further, they were characterized and ranked according to their cost, speed, sensitivity and selectivity. Suggested improvements were offered as well as future research endeavors to accommodate anticipated environmental changes.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2013/esthag.2013.47.issue-16/es401245k/production/images/medium/es-2013-01245k_0004.gif'></P>

Is the Tumor Infiltrating Natural Killer Cell (NK-TILs) Count in Infiltrating Ductal Carcinoma of Breast Prognostically Significant?

Rathore, Ankita Singh,Goel, Madhu Mati,Makker, Annu,Kumar, Sandeep,Srivastava, Anand Narain Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8

Purpose: The aim of this study was to investigate the prognostic significance of the CD56+NK-TIL count in infiltrating ductal carcinoma (IDC) of breast. Material and Methods: Immunohistochemistry (IHC) was performed using antibodies specific for CD56 on formalin-fixed and paraffin-embedded tissue sections of 175 infiltrating ductal carcinomas (IDC) of breast. Distribution of intratumoral and stromal CD56+NK-TILs was assessed semi-quantitatively. Results: A low intratumoral CD56+count showed significant and inverse associations with tumor grade, stage, and lymph node status, whereas it had significant and direct association with response to treatment indicating good prognosis. These patients had better survival (${\chi}^2$=4.80, p<0.05) and 0.52 fold lower death rate (HR=0.52, 95% CI=0.28-0.93) as compared to patients with high CD56+ intratumoral count. The association of survival was insignificant with low CD56 stromal count as compared to high CD56 stromal count (${\chi}^2$=1.60, p>0.05). Conclusion: To conclude, although NK-TIL count appeared as a significant predictor of prognosis, it alone may not be sufficient for predicting the outcome considering the fact that there exists a crosstalk between NK-TILs and the other immune infiltrating TILs.

Experimental strategy for acid-free plutonium recovery from assorted matrices: Non-aqueous leaching followed by selective solid phase extraction

Kumar Shiny Suresh,Rao Ankita,Srivastava Ashutosh,Yadav Kartikey Kumar,Lenka Raja Kishore 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.11

Methodologies comprising usage of innocuous reagents, lower overall chemical inventory and simplification of process scheme for plutonium recovery from assorted matrices, solid as well as liquid, are key to establishing sustainability of the nuclear fuel cycle. The present study demonstrates, for the first-time, plutonium leaching from different refractory matrices: oxide, mixed oxide as well as simulated cellulosic waste using the benign halide anion free choline citrate - urea (1 : 2 mole ratio) based eutectic solvent (referred to as CU). This mineral acid and hydrofluoric acid-free, non-aqueous route of plutonium recovery with controlled infra-red heating yielded ≥93% efficiency. CU was diluted with biodegradable, less viscous propylene glycol (referred to as PG), which was chosen as the non-aqueous polar phase for facile solid phase extraction (SPE), which is a green alternative to liquid-liquid extraction owing to process simplification and solvent inventory reduction. Exclusive stabilization of tetravalent plutonium in the novel media, confirmed by ultraviolet-visible spectrophotometry and electrochemical methods, led to process simplification, eliminating any pre-extraction requirement for oxidation state adjustment. Extractant, di-2-ethyl hexyl phosphoric acid encapsulated polyether sulfone beads, prepared by phase inversion method, were employed for efficient SPE of plutonium (Distribution co-efficient, kD=950±6). Selectivity of non-aqueous SPE was found to be Pu(IV)≫UO 2+ 2 >Am(III) vis-à-vis aqueous acid medium.

Optimal Placement of TCSC For Enhancement of Power System Stability Using Heuristic Methods : An Overview

Shishir Dixit,Laxmi Srivastava,Ankita Singh,Ganga Agnihotri 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6

Flexible Alternating Current Transmission Systems (FACTS) represents a vast development in the area of power system operation and control. As we know that under heavily loaded conditions our power system is at high risks of consequent voltage instability problem. This paper gives an overview about application of series connected Flexible alternating current transmission system (FACTS) for improvement of power system performance like transfer stability, secure voltage profile and reduce the system losses etc. FACTS devices require huge capital investment. Therefore, heuristic techniques are used for optimal location and sizing of series FACTS controllers like Genetic Algorithm (GA), Particle Swarm Optimization (PSO) etc. These techniques are used to solve the optimization problem. This paper gives details of optimal placement and sizing of FACTS devices based on different evolutionary techniques which is used for minimization of transmission loss, enhancement of stability of power system. In this study one of the FACTS devices is used as a scheme for enhancement of power system stability.Proper installation of FACTS devices also results in significant reduction of transmission loss. In this review,TCSC is selected as the compensation device.

Optimized cultivation of Ettlia sp. YC001 in eutrophic pond water for nutrient removal and biomass production

Hyung-Seok Oh,Chi-Yong Ahn,Ankita Srivastava,오희목 한국조류학회I 2018 ALGAE Vol.33 No.4

Ettlia sp. YC001, a highly settleable and productive microalga, was shown to be effective in removing nutrients andcapturing suspended solids from eutrophic pond water. The optimum conditions for the Ettlia sp. YC001 cultivationwere investigated using water from a landscape pond. The pond water was supplemented with different N : P ratios byweight, and the biomass production and nutrient removal compared in batch cultures. The maximum removal rate ofN and P was with an N : P ratio of 16 : 1. Plus, the turbidity dropped to near zero within 4 days. Meanwhile, chemostatcultivation showed that the biomass productivity and nutrient removal rate increased when increasing the dilution rate,where a dilution rate of 0.9 d-1 showed the highest N and P removal rate at 32.4 mg L-1 d-1 and 1.83 mg L-1 d-1, respectively,and highest biomass and lipid productivity at 0.432 g L-1 d-1 and 67.8 mg L-1 d-1, respectively. The turbidity was also reducedby 98% in the chemostat cultivation. Moreover, auto-flocculation and pH were closely connected to the turbidityremoval. As a result, this study identified the optimal N : P ratio for small pond water treatment using an Ettlia sp. YC001,while also establishing the optimal conditions for nutrient removal, turbidity reduction, and biomass production.