Orly Levitan

Orly Levitan
Rutgers, The State University of New Jersey | Rutgers · Department of Marine and Coastal Sciences

PhD

About

24
Publications
3,948
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1,481
Citations
Additional affiliations
October 2010 - August 2017
Rutgers, The State University of New Jersey
Position
  • Professor

Publications

Publications (24)
Article
Full-text available
A descendant of the red algal lineage, diatoms are unicellular eukaryotic algae characterized by thylakoid membranes that lack the spatial differentiation of stroma and grana stacks found in green algae and higher plants. While the photophysiology of diatoms has been studied extensively, very little is known about the spatial organization of the mu...
Article
Under nutrient deplete conditions, diatoms accumulate between 15 to 25% of their dry weight as lipids, primarily as triacylglycerols (TAGs). As in most eukaryotes, these organisms produce TAGs via the acyl-CoA dependent Kennedy pathway. The last step in this pathway is catalyzed by diacylglycerol acyltransferase (DGAT) that acylates diacylglycerol...
Article
When diatoms are stressed for inorganic nitrogen, they remodel intermediate metabolism and redirect carbon towards lipid biosynthesis; however, this response comes at a significant cost reflected in decreased photosynthetic energy conversion efficiency and growth. Here we explored a molecular genetic approach to restrict the assimilation of inorgan...
Article
Phytoplankton form the foundation of the marine food web and regulate key biogeochemical processes. These organisms face multiple environmental changes, including the decline in ocean pH (ocean acidification) caused by rising atmospheric p CO 2 (ref.). A meta-analysis of published experimental data assessing growth rates of different phytoplankton...
Article
Diatoms are unicellular algae that accumulate significant amounts of triacylglycerols as storage lipids when their growth is limited by nutrients. Using biochemical, physiological, bioinformatics, and reverse genetic approaches, we analyzed how the flux of carbon into lipids is influenced by nitrogen stress in a model diatom, Phaeodactylum tricornu...
Article
Full-text available
Improving feedstock is critical to facilitate the commercial utilization of algae, in particular in open pond systems where, due to the presence of competitors and pests, high algal growth rates and stress tolerance are beneficial. Here we raised laboratory cultures of the model alga Chlamydomonas reinhardtii under serial dilution to explore the po...
Article
Long-term global climate change, caused by burning petroleum and other fossil fuels, has motivated an urgent need to develop renewable, carbon-neutral, economically viable alternatives to displace petroleum using existing infrastructure. Algal feedstocks are promising candidate replacements as a 'drop-in' fuel. Here, we focus on a specific algal ta...
Article
Global warming may exacerbate inorganic nutrient limitation, including phosphorus (P), in the surface-waters of tropical oceans that are home to extensive blooms of the marine diazotrophic cyanobacterium, Trichodesmium. We examined the combined effects of P-limitation and pCO2, forecast under ocean acidification scenarios, on Trichodesmium erythrae...
Data
Global warming may exacerbate inorganic nutrient limitation, including phosphorus (P), in the surface-waters of tropical oceans that are home to extensive blooms of the marine diazotrophic cyanobacterium, Trichodesmium. We examined the combined effects of P limitation and pCO2, forecast under ocean acidification scenarios, on Trichodesmium erythrae...
Article
Full-text available
It is widely established that nutritional nitrogen deprivation increases lipid accumulation but severely decreases growth rate in microalgae. To understand the regulatory branch points that determine the partitioning of carbon among its potential sinks, we analyzed metabolite and transcript levels of central carbon metabolic pathways and determined...
Data
Pearson correlations of the enrichment of the 21 genes of interest over the day. i‐ 1 h after the onset of light; ii‐ 5h after the onset of light; iii‐ 9 h after the onset of light; iv‐ 13 h after the onset of light. Relative abundance estimated according to the 2‐ΔΔCt method, with 16S rRNA as the endogenous reference gene, and average ΔCt values o...
Data
Daily mRNA transcript enrichment of 12 GOIs, not significantly influenced by changing environmental factors. Significant influence of pCO2 (400 and 900 µatm) temperature (25 and 31 °C) and their interaction, on the GOI expression was done according to a 3‐Way ANOVA (p<0.05, Table 3). The left panel represent GOIs that no influencing factor (bicA2,...
Article
Full-text available
Growth, protein amount, and activity levels of metabolic pathways in Trichodesmium are influenced by environmental changes such as elevated pCO(2) and temperature. This study examines changes in the expression of essential metabolic genes in Trichodesmium grown under a matrix of pCO(2) (400 and 900 µatm) and temperature (25 and 31°C). Using RT-qPCR...
Article
Full-text available
The marine diazotrophic cyanobacterium Trichodesmium responds to elevated atmospheric CO(2) partial pressure (pCO(2)) with higher N(2) fixation and growth rates. To unveil the underlying mechanisms, we examined the combined influence of pCO(2) (150 and 900 microatm) and light (50 and 200 micromol photons m(-2) s(-1)) on Trichodesmium IMS101. We exp...
Article
Full-text available
Recent studies on the diazotrophic cyanobacterium Trichodesmium erythraeum (IMS101) showed that increasing CO(2) partial pressure (pCO(2)) enhances N(2) fixation and growth. Significant uncertainties remain as to the degree of the sensitivity to pCO(2), its modification by other environmental factors, and underlying processes causing these response...
Article
Full-text available
We examined the influence of forecasted changes in global temperatures and pCO(2) on N(2) fixation and assimilation in the ecologically important cyanobacterium Trichodesmium spp. Changes of mRNA transcripts (nifH, glnA, hetR, psbA, psaB), protein (nitrogenase, glutamine synthetase) pools and enzymatic activity (nitrogenase) were measured under var...
Data
The marine diazotrophic cyanobacterium Trichodesmium responds to elevated atmospheric CO2 partial pressure (pCO2) with higher N2 fixation and growth rates. To unveil the underlying mechanisms, we examined the combined influence of pCO2(150 and 900 µatm) and light (50 and 200 µmol photons m-2 s-1) on TrichodesmiumIMS101. We expand on a complementary...
Data
Recent studies on the diazotrophic cyanobacterium Trichodesmium erythraeum(IMS101) showed that increasing CO2 partial pressure (pCO2) enhances N2 fixation and growth. Significant uncertainties remain as to the degree of the sensitivity to pCO2, its modification by other environmental factors, and underlying processes causing these responses. To add...
Article
Full-text available
The area of the Dead Sea, bordering Jordan and Israel, contains many springs with different physical and chemical properties. Hot springs are found on the eastern shore of the lake: the springs of Zara (the ancient Callirrhoe) with temperatures up to 59 °C and those of Zerka Ma'in, 5 km inland. The latter springs, mentioned by Josephus (1st century...
Article
Full-text available
Bioassay experiments were performed to identify how growth of key groups within the microbial community was simultaneously limited by nutrient (nitrogen and phosphorus) availability during spring in the Gulf of Aqaba's oceanic waters. Measurements of chlorophyll a (chl a) concentration and fast repetition rate (FRR) fluorescence generally demonstra...
Article
* As iron (Fe) deficiency is a main limiting factor of ocean productivity, its effects were investigated on interactions between photosynthesis and nitrogen fixation in the marine nonheterocystous diazotrophic cyanobacterium Trichodesmium IMS101. * Biophysical methods such as fluorescence kinetic microscopy, fast repetition rate (FRR) fluorimetry,...
Article
Full-text available
Extracellular polysaccharide aggregates, operationally defined as transparent exopolymeric particles (TEP), are recognized as an important conduit for carbon recycling and export in aquatic systems. Yet, the factors controlling the build-up of the TEP pool are not well characterized. Here we show that increased TEP production by Trichodesmium, an o...
Article
The increases in atmospheric pCO2 over the last century are accompanied by higher concentrations of CO2(aq) in the surface oceans. This acidification of the surface ocean is expected to influence aquatic primary productivity and may also affect cyanobacterial nitrogen (N)-fixers (diazotrophs). No data is currently available showing the response of...