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    Zvi Cohen

    Publisher Summary The Very Long-Chain Polyunsaturated Fatty Acids (VLC-PUFAs) of the n-3 family are abundant in microalgae. Plants accumulate Triacylglycerol (TAG) to store energy. The TAG of most algal species contain mostly saturated... more
    Publisher Summary The Very Long-Chain Polyunsaturated Fatty Acids (VLC-PUFAs) of the n-3 family are abundant in microalgae. Plants accumulate Triacylglycerol (TAG) to store energy. The TAG of most algal species contain mostly saturated and monounsaturated fatty acid (FA); these FA are less complicated to produce and provide more energy. The studies of the red microalga, P. cruentum, have shown that VLC-PUFA accumulated in TAG can be utilized to biosynthesize the eukaryotic-like molecular species of chloroplastic lipids, especially at low temperatures. It was hypothesized that some algae whose habitat is characterized by rapidly changing environmental conditions can swiftly adapt to these conditions by mobilizing VLC-PUFA from their TAG to chloroplastic lipids. Based on the hypothesis, a chlorophyte microalga, P. incisa, was isolated. That led to the search for polyunsaturated fatty acid-rich photosynthetic microalgae.
    Publisher Summary There is a common problem of biomass recovery from the fermenter and the subsequent extraction of the oil. Therefore, for the Single Cell Oils (SCOs) that are rich in a particular Polyunsaturated Fatty Acid (PUFA), there... more
    Publisher Summary There is a common problem of biomass recovery from the fermenter and the subsequent extraction of the oil. Therefore, for the Single Cell Oils (SCOs) that are rich in a particular Polyunsaturated Fatty Acid (PUFA), there is a need to avoid sustained high temperatures or conditions that could lead to the oxidation and rancidity of the oils during their extraction. The first commercially viable SCO process was the production of an oil rich in Gamma-Linolenic Acid (GLA) from Mucor circinelloide . Examination of the first batch of oil extracted from M. circinelloides indicated the presence of free fatty acids at about 3%–5% of the total oil, which then contributed certain undesirable characteristics to the oil. These free fatty acids were quickly realized to be artifacts of the downstream processing system, as they were not present if the oil was quickly extracted from small samples of biomass taken from laboratory level fermenters. Over 98% of the oil within the cells of M. circinelloides could be extracted directly, using hexane, in one of the speciality extractors. Once the oil is extracted, its further refinement and purification follows conventional procedures.
    ... INCISA P. SHRESTHA 1 , D. COHEN 1,2 , I. KHALILOV 1 , I. KHOZIN–GOLDBERG 1 and ... 2002). Cellular fractionation: Due to their very adamant cell walls, the cells werefrozen in liquid nitrogen and ground with mortar and pestle. ...
    Parietochloris incisa is a unicellular freshwater green alga capable of accumulating high amounts of the valuable long-chain polyunsaturated arachidonic acid (AA) in triacylglycerols (TAG) of cytoplasmic oil bodies. To find the... more
    Parietochloris incisa is a unicellular freshwater green alga capable of accumulating high amounts of the valuable long-chain polyunsaturated arachidonic acid (AA) in triacylglycerols (TAG) of cytoplasmic oil bodies. To find the cultivation conditions providing maximum AA yield, the effects of illumination and N-availability on the dry weight (DW), chlorophyll, carotenoid, and AA content were studied. Under nitrogen starvation, TAG accounted
    The chemical composition of the lipophylic fraction from the halophytic plant Euphorbia peplis L. was investigated. Compared to other terrestrial higher plants an increase of triacylglycerols and especially of glycolipids was observed.... more
    The chemical composition of the lipophylic fraction from the halophytic plant Euphorbia peplis L. was investigated. Compared to other terrestrial higher plants an increase of triacylglycerols and especially of glycolipids was observed. The main phospholipid was phosphatidyl choline, followed by almost equal concentrations of phosphatidyl ethanolamine and phosphatidyl glycerol. A relatively high concentration of phosphatidic acids (6.5% of the total phospholipids) was found. The main sterol appeared to be sitosterol and significant amounts of tetracyclic triterpene alcohols were found. The composition of the volatile compounds is relatively simple and only one chlorinated compound, identified as 2,2-diethoxy-1-chloroethane, was found. There was a strong toxicity of the total lipophylic extract towards Artemia salina.
    Abstract The fatty acid distribution in 19 strains of Spirulina was studied. All but one contained γ-linolenic acid (GLA). No GLA was found in S. subsalsa, which had a very high content of palmitoleic acid. The fatty acid content of all... more
    Abstract The fatty acid distribution in 19 strains of Spirulina was studied. All but one contained γ-linolenic acid (GLA). No GLA was found in S. subsalsa, which had a very high content of palmitoleic acid. The fatty acid content of all but one of the tested strains ...
    Gene Ahlborn (Raleigh, North Carolina, USA) Efstathios Alichanidis (Thessaloniki, Greece) Rotimi E. Aluko (Winnipeg, Manitoba, Canada) Luciana Alves de Oliveira (Cruz das Almas, Brazil) Myriam Arriaga Alba (Mexico City, Mexico) Francisco... more
    Gene Ahlborn (Raleigh, North Carolina, USA) Efstathios Alichanidis (Thessaloniki, Greece) Rotimi E. Aluko (Winnipeg, Manitoba, Canada) Luciana Alves de Oliveira (Cruz das Almas, Brazil) Myriam Arriaga Alba (Mexico City, Mexico) Francisco Artés (Cartagena, Spain) William E. Artz (Urbana, Illinois, USA) María Jesús Ayuso (Sevilla, Spain) Rintu Banerjee (Kharagpur, India) Mara Banovi} (Zagreb, Croatia) Slobodan Barbari} (Zagreb, Croatia) ... Maria Teresa Batista (Coimbra, Portugal) Alev Bayindirli (Ankara, Turkey) Sun~ica Beluhan (Zagreb, Croatia) ...
    Phase variation in the colonial opacity of Streptococcus pneumoniae has been implicated as a factor in the pathogenesis of pneumococcal disease. This study examined the relationship between membrane characteris- tics and colony morphology... more
    Phase variation in the colonial opacity of Streptococcus pneumoniae has been implicated as a factor in the pathogenesis of pneumococcal disease. This study examined the relationship between membrane characteris- tics and colony morphology in a few selected opaque-transparent couples of S. pneumoniae strains carrying different capsular types. Membrane fluidity was determined on the basis of intermolecular excimerization of pyrene and
    The oleaginous microalga Lobosphaera incisa (Trebouxiophyceae, Chlorophyta) contains arachidonic acid (ARA, 20:4 n-6) in all membrane glycerolipids and in the storage lipid triacylglycerol. The optimal growth temperature of the wild-type... more
    The oleaginous microalga Lobosphaera incisa (Trebouxiophyceae, Chlorophyta) contains arachidonic acid (ARA, 20:4 n-6) in all membrane glycerolipids and in the storage lipid triacylglycerol. The optimal growth temperature of the wild-type (WT) strain is 25°C; chilling temperatures (≤15°C) slow its growth. This effect is more pronounced in the delta-5-desaturase ARA-deficient mutant P127, in which ARA is replaced with dihomo-γ-linolenic acid (DGLA, 20:3 n-6). In nutrient-replete cells grown at 25°C, the major chloroplast lipid monogalactosylglycerol (MGDG) were dominated by C18/C16 species in both strains. Yet ARA constituted over 10% of the total fatty acids in the WT MGDG as a component of C20/C18 and C20/C20 species, whereas DGLA was only a minor component of MGDG in P127. Both strains increased the percentage of 18:3 n-3 in membrane lipids under chilling temperatures. The temperature downshift led to a dramatic increase in triacylglycerol at the expense of chloroplast lipids. WT a...
    An iodinated starch suspension was used as a model particulate hepatic contrast agent for computed tomography (CT). The material, synthesized from starch and triiodobenzoic acid, formed a stable concentrated suspension, containing... more
    An iodinated starch suspension was used as a model particulate hepatic contrast agent for computed tomography (CT). The material, synthesized from starch and triiodobenzoic acid, formed a stable concentrated suspension, containing particles smaller than 4 micrometer. Following intravenous administration of 0.16 gI/kg to rabbits, approximately 85% of the injected dose was present in the liver, resulting in a 180 to 200 Hounsfield unit (1,000 scale) increase in liver CT value. The material produced marked and sustained normal liver opacification but no hepatic tumor enhancement. Lesions as small as 2 mm in diameter were detected. The approximate LD50 of the suspension in mice was 0.9 g I/kg. There were no signs of toxicity at sublethal doses. This suspension produces greater, more sustained, and more selective liver opacification than conventional biliary and urographic contrast materials.

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