Effects of Different Dietary Lipid Contents on Growth and Lipase Activity of Eriocheir sinensis Larvae

The effects of different dietary lipid content on the growth and lipase activity ofEriocheir sinensis larvae were studied in the paper. The results showed that the survival, metamorphic rate and weight gain of E. sinensis larvae at different stages of growth all varied significantly with lipid content （P〈0.05）. Further, the survival and metamorphosis rates were the highest during the larval phases Z3 to Z4, and the weight gain was the highest during the larval phases Z5 to M. During the first 20h after metamorphosis of every larval stage, the lipase activity increased over time at Z1, Z2, Z3 and M and declined at Z4 and Zs, and was influenced significantly by lipid content （P〈0.05）. In addition, lipase activity at each larval stage began to respond to dietary lipid contents 4h after the larvae were fed, and tended to be stable after 12 h. The diets with higher lipase activity and lower lipid content were selected to give the suitable recipe of lipid requirements at each larval stage. It was concluded that the suitable lipid requirements at Zb Z2, Z3, Z4, Z5 and M were 6%, 4% 6%, 8%, 8% and 10%, respectively.

The effects of season on fatty acid composition and ω3/ω6 ratios of northern pike(Esox lucius L.,1758) muscle lipids

In the present study, the effects of season on fatty acid composition, total lipids, and ω3/ω6 ratios of northern pike muscle lipids in Klzlhrmak River （Klrlkkale, Turkey） were investigated. A total of 35 different fatty acids were determined in gas chromatography. Among these, palmitic, oleic, and palmitoleic acids had the highest proportion. The main polyunsaturated fatty acids （PUFAs） were found to be docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid. There were more PUFAs than monounsaturated fatty acids （MUFA） in all seasons. Similarly, the percentages of ω3 fatty acids were higher than those of total ω6 fatty acids in the fatty acid composition. ω3/ω6 ratios were calculated as 1.53, 1.32, 1.97, and 1.71 in spring, summer, autumn and winter, respectively. Overall, we found that the fatty acid composition and ω3/ω6 fatty acid ratio in the muscle of northern pike were significantly influenced by season.

Relationship between bioaccumulation，distribution of MET and lipid content of aquatic organisms

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Trans-10,cis-12 conjugated linoleic acid reduces neutral lipid content and may affect cryotolerance of in vitro-produced crossbred bovine embryos

Background：Due to high neutral lipids accumulation in the cytoplasm,in vitro-produced embryos from Bos primigenius indicus and their crosses are more sensitive to chilling and cryopreservation than those from Bos primigenius taurus.The objective of the present study was to evaluate the effects of trans-10,cis-12 conjugated linoleic acid（CLA） on the development and cryotolerance of crossbred Bos primigenius taurus x Bos primigenius indicus embryos produced in vitro,and cultured in the presence of fetal calf serum.Bovine zygotes（n = 1,692）were randomly assigned to one of the following treatment groups：1） Control,zygotes cultured in Charles Rosenkrans 2 amino acid（CR2aa） medium（n = 815） or 2） CLA,zygotes cultured in CR2 aa medium supplemented with 100 μmol/L of trans-10,cis-12 CLA（n =877）.Embryo development（cleavage and blastocyst rates evaluated at days 3 and 8 of culture,respectively）,lipid content at morula stage（day 5） and blastocyst cryotolerance（re-expansion and hatching rates,evaluated 24 and 72 h post-thawing,respectively） were compared between groups.Additionally,selected mRNA transcripts were measured by Real-Time PCR in blastocyst stage.Results：The CLA treatment had no effect on cleavage and blastocyst rates,or on mRNA levels for genes related to cellular stress and apoptosis.On the other hand,abundance of mRNA for the 1-acylglycerol-3-phosphate0-acyltransferase-encoding gene（AGPAT）,which is involved in triglycerides synthesis,and consequently neutral lipid content,were reduced by CLA treatment.A significant increase was observed in the re-expansion rate of embryos cultured with trans-10,cis-12 CLA when compared to control（56.3 vs.34.4%,respectively,P = 0.002）.However,this difference was not observed in the hatching rate（16.5 vs.14.0%,respectively,P=0.62）.Conclusions：The supplementation with trans-10,ds-12 CLA isomer in culture medium reduced the lipid content of in vitro produced bovine embryos by reducing the gene expression of 1-acylglycerol 3-phosphate 0-acyltransferase（AGPAT） enzyme.However,a possible improvement in embryo cryotolerance in response to CLA,as suggested by increased blastocyst re-expansion rate,was not confirmed by hatching rates.

The Effect of Salinity on Growth, Dry Weight and Lipid Content of the Mixed Microalgae Culture Isolated from Glagah as Biodiesel Substrate

Microalgae use photosynthesis to convert solar energy into chemical energy, such as lipid and they can be a replacement for oil-based fuels. They are among the fastest growing plants in the world, and about 50% of their weight is oil. This lipid oil can be used to make biodiesel. Unfortunately, there are only some of potential strains isolated from Indonesia and most of the biodiesel productions are usually using a single strain. Then, although they are rich of oils, their biomass productivity is still low. Salinity treatment can be used to increase their biomass as well as their lipid content. Therefore, the research aim was to study the effect of salinity on the growth, dry weight and lipid content of mixed microalgae isolated from Glagah, Yogyakarta. The mixed microalgae were cultured in 3NBBM medium with different salinities or types of water （sea water, brackish water, and fresh water）. The cultures were incubated at light intensity 3,000 lux under dark：light exposure of 12：12 h for 7 days. The number of cells was counted every 24 h with a Haemocytometer, and the biomass was calculated based on the dry weight. The lipid content was measured on days 0, 3, and 7 using NR （Nile Red） staining, and then the amount of lipid was analyzed using a fluorescence microscope and measured with CellProfiler 2.0 software. The highest dry weight and lipid content were found in seawater medium, they accounted for 3.42 mg/mL and 13.58% at day 7, respectively. Whereas, the highest number of cells was found in freshwater medium, this was 9.8 × 10^6 cells/mL.

Effects of nutrient limitations on the sinking velocity of Thalassiosira weissflogii

The sinking of diatoms is critic al to the formation of oceanic biological pumps and coastal hypoxic zones.However,little is known about the effects of different nutrient restrictions on diatom sinking.In this study,we measured the sinking velocity(SV) of Thalassiosira weissflogii using a new phytoplankton video observation instrument and analyzed major biochemical components under varying nutrient conditions.Our results showed that the SV of T.weissflogii under different nutrient limitation conditions varied substantially.The highest SV of(1.77±0.02) m/d was obtained under nitrate limitation,signific antly surpassing that under phosphate limitation at(0.98±0.13) m/d.As the nutrient limitation was released,the SV steadily decreased to(0.32±0.03) m/d and(0.15±0.05) m/d,respectively.Notably;under conditions with limited nitrate and phosphate concentrations,the SV values of T.weissflogii significantly positively correlated with the lipid content(P <0.001),with R^(2) values of 0.86 and 0.69,respectively.The change of the phytoplankton SV was primarily related to the intracellular compo sition,which is controlled by nutrient conditions but did not significantly correlate with transparent extracellular polymer and biosilica contents.The results of this study help to understand the regulation of the vertical sinking process of diatoms by nutrient restriction and provide new insights into phytoplankton dynamics and their relationship with the marine nutrient structure.

Effects of Fed-batch and Nitrogen-deficient Culture on Lipid Yield of Chlorella sp.

[Objective] This study was to realize high-density culture of Chlorella sp. as well as the culture with high lipid yield. [Method] Through analyzing the growth curve of Chlorella sp. cells, dextrose consumption curve, change curves of pH and dissolved oxygen, a fed-batch culture was conducted, followed by a nitrogen-deficient culture aiming at accumulating the lipids in Chlorella sp. cells when a high density of Chlorella sp. cells was obtained. [Result] After four batches of feeding were pro- vided, the biomass of Chlorella sp. reached up to 65.25 g/L, and the lipid content increased from 42.75% to 63.82% in Chlorella sp. cells, with the yield of 43.37 g/L in the following 12 hours of nitrogen-deficient culture. [Conclusion] Reasonable fed- batch can significantly improve the biomass of Chlorella sp., and the nitrogen-defi- cient culture further raises the lipid yield of Chlorella sp.

TOTAL LIPID AND FATTY ACID COMPOSITION OF EIGHT STRAINS OF MARINE DIATOMS

Fatty acid composition and total lipid content of 8 strains of marine diatoms ( Nitzschia frustrula, Nitzschia closterium, Nitzschia incerta, Navicula pelliculosa,Phaeodactylum tricornutum, Synedra fragilaroides ) were examined. The microalgae were grown under defined conditions and harvested at the late exponential phase. The major fatty acids in most strains were 14:0 (1.0%-6.3%), 16:0 (13.5%-26.4%), 16:1n-7 (21.1%-46.3%) and 20:5n-3 (6.5%-19.5%). The polyunsaturated fatty acids 16:2n-4, 16:3n-4, 16:4n-1 and 20:4n-6 also comprised a significant proportion of the total fatty acids in some strains. The characteristic fatty acid composition of diatoms is readily distinguishable from those of other microalgal groups. Significant concentration of the polyunsaturated fatty acid 20:5n-3 (eicosapentaenoic acid) was present in each strain, with the highest proportion in B222 (19.5%).

Effects of the potassium application rate on lipid synthesis and eating quality of two rice cultivars

Lipid content has an important effect on rice eating quality,but the effects of fertilizer application rate on the lipid synthesis and eating quality of rice are not well understood.Potassium(K)has a strong influence on rice quality and the requirement for K fertilizer in rice is greater than for nitrogen(N)and phosphorus(P)fertilizers.To investigate the effects of K fertilizer on the lipid synthesis and eating quality of rice,we used Nanjing 9108(NJ9108,japonica)and IR72(indica)rice as experimental materials and four K levels:K0(0 kg ha^(-1)),K1(90 kg ha^(-1)),K2(135 kg ha^(-1))and K3(180 kg ha^(-1)).The results showed that the lipid content,free fatty acid(FFA)content,unsaturated fatty acid(UFA)content,malonyl-CoA(MCA)content,phosphatidic acid(PA)content,lipid synthesis-related enzyme activities and eating quality first increased and then decreased with increasing K in both cultivars.The maximum values were obtained under K2.However,the saturated fatty acid(SFA)content showed the opposite trend.No significant differences were found in pyruvate(PYR)content among the K treatments.The protein and oxaloacetic acid(OAA)contents and phosphoenolpyruvate carboxylase(PEPCase)activity of NJ9108 first decreased and then increased with increasing K,and the minimum values were obtained under K2;while IR72 showed the opposite trend and the maximum values were obtained under K1.Overall,increasing K optimized the fatty acid components and increased the lipid content and eating quality of rice by enhancing lipid synthesis-related enzyme activities and regulating substrate competition for lipid and protein synthesis.The optimal K application rate for lipid synthesis,eating quality and grain yield was 135 kg ha^(-1)for both cultivars.

Purification of a Diatom and Its Identification to Cylindrotheca closterium

A diatom was purified with colony selection and continuous dilution methods. It was identified to Cylindrotheca closterium according to its morphological characteristics and rbc L and 18 s r RNA gene sequences. The alga was not sensitive to ampicillin and neomycin, but sensitive to chloramphenicol which inhibited its growth at concentrations ranging from 50 to 150 μg m L-1. The purified alga was easy to culture and its specific growth rate was 0.207 ± 0.002(d-1). It was resistant to pollution and could be harvested in an easy way. It was relatively high in lipid content(20.08% ± 0.67% of dry weight) and the combined amount of its 16:0 and 16:1(n-7), the most suitable resource of biodiesel, was as high as 64% of the total fatty acids, while the amount of polyunsaturated fatty acids reached 19.96%–20% of the total fatty acids. Thus the purified C. closterium can be cultured as a biodiesel producer or a nutrition supplement producer.

The influence of lipid-extraction on theδ^(13)C of mesopelagic and demersal fish in the South China Sea:modification and application of lipid normalization models

Mesopelagic fish,the most important daily vertically migrating community in the oceans,are characterized by high lipid content which may obscure the interpretation of stable isotopes analysis.Demersal fish,which are important consumers in the food web dominated by mesopelagic fish,also have a high lipid content.Here we collected 127 fish samples from the South China Sea and evaluated the effect of lipid contents on△δ^(13)C of mesopelagic and demersal fish.In lipid-extracted mesopelagic fish,the C/N content ratio(<5.5)shows a clear correlation withΔδ^(13)C(the offset of bulk and lipid-extractedδ^(13)C values),especially in non-migratory and semi-migratory species;these values were less correlation in demersal fish.Based on our results,we suggest that mesopelagic and demersal fish in different regions of the South China Sea should be studied separately using appropriate correction models and less fit for the traditional model.Moreover,the C/N content ratio should be used cautiously for establishing the lipid normalization model,especially for the fish in migratory mesopelagic fish and demersal fish.Our results also reveal that mesopelagic fish across nearby regions could be analyzed together.The new models described here can be applied in future studies of mesopelagic and demersal fish in the South China Sea.

An Aggregation-Induced Emission Optical Highlighter for the Studies of Endoplasmic Reticulum-Lipid Droplet Content Dynamics

The lipid droplet(LD)is a dynamic organelle responsible for lipid storage and metabolism that plays important roles in maintaining lipid homeostasis.However,limited strategies are available for tracking the LD content exchange.In this contribution,we report a novel fluorescent probe,TPEAmAl,for real-time LD content dynamics tracking.TPE-AmAl is LD-specific,but emits faintly due to its intramolecular motion.Upon photoactivation,it undergoes a photocyclodehydrogenation reaction and shows a large fluorescence increment.Thus,it can be used for highlighting selected LDs with high spatial resolution.By measuring the fluorescence changes in the distal region,the lipid content exchange efficiency can be estimated.In our experiment,LD content exchange rate differences between nascent and mature LDs as well as cells with normal and deficient LD budding machinery are observed.This probe expands the fluorescence-based toolbox for LD content dynamics studies.

Effect of nitrogen and extraction method on algae lipid yield

Effects of nitrogen source and concentration as well as lipid extraction method on the lipid yield of autotrophic Scenedesmus dimorphus and heterotrophic Chlorella protothecoides were studied.Three concentration levels of nitrate,urea and glycine/yeast extract as the nitrogen source were investigated.The highest lipid yield of S.dimorphus in the 17-d autotrophic culture was 0.40 g/L from the 1.8 g/L urea medium,and the maximum lipid yield of C.protothecoides in the nine-day heterotrophic culture was 5.89 g/L from the 2.4 g/L nitrate medium.Four different cell disruption methods-bead-beater,French press,sonication and wet milling-were studied for their effectiveness in solvent extraction of algal lipids from S.dimorphus and C.protothecoides.Wet milling followed by hexane extraction was most effective for S.dimorphus lipid extraction,whereas bead-beater disruption followed by hexane extraction was best for C.protothecoides.