Development of a High-Performance Thin-Layer Chromatography Method for the Quantification of Alkyl Glycerolipids and Alkenyl Glycerolipids from Shark and Chimera Oils and Tissues

Ether lipids are composed of alkyl lipids with an ether bond at the sn-1 position of a glycerol backbone and alkenyl lipids, which possess a vinyl ether bond at the sn-1 position of the glycerol. These ether glycerolipids are present either as polar glycerophospholipids or neutral glycerolipids. Before studying the biological role of molecular species of ether glycerolipids, there is a need to separate and quantify total alkyl and alkenyl glycerolipids from biological samples in order to determine any variation depending on tissue or physiopathological conditions. Here, we detail the development of the first high-performance thin-layer chromatography method for the quantification of total alkyl and alkenyl glycerolipids thanks to the separation of their corresponding alkyl and alkenyl glycerols. This method starts with a reduction of all lipids after extraction, resulting in the reduction of neutral and polar ether glycerolipids into alkyl and alkenyl glycerols, followed by an appropriate purification and, finally, the linearly ascending development of alkyl and alkenyl glycerols on high-performance thin-layer chromatography plates, staining, carbonization and densitometric analysis. Calibration curves were obtained with commercial alkyl and alkenyl glycerol standards, enabling the quantification of alkyl and alkenyl glycerols in samples and thus directly obtaining the quantity of alkyl and alkenyl lipids present in the samples. Interestingly, we found a differential quantity of these lipids in shark liver oil compared to chimera. We quantified alkyl and alkenyl glycerolipids in periprostatic adipose tissues from human prostate cancer and showed the feasibility of this method in other biological matrices (muscle, tumor).     

Ecotoxicological testing of sediments and dredged material: an overlooked opportunity?

Purpose

Basing decisions for the management of contaminated sediments on ecotoxicological data is still often met with skepticism by European stakeholders. These concerns are discussed as they pertain to bioassays to show how ecotoxicological data may provide added value for the sustainable management of sediment in aquatic systems.

Materials and methods

Five “concerns” are selected that are often raised by stakeholders. The ecotoxicological practice is discussed in light of the knowledge gained in recent decades and compared with chemical sediment analysis and chemical data.

Results and discussion

Common assumptions such as a higher uncertainty of biotest results for sediments compared to chemical analyses are not supported by interlaboratory comparisons. Some confusion also arises, because the meaning of biotest data is often misunderstood, questioning their significance in light of a limited number of organisms and altered test conditions in the lab. Because biotest results describe a sediment property, they should not be directly equated with an impact upon the biological community. To identify a hazard, however, the possibility of false-negative results due to the presence of contaminants that are not analyzed but are toxic is lower.

Conclusions

The cost of increased investment in ecotoxicological tests is, in our view, small compared with that of making false-negative assessments of sediment/dredged material that can ultimately have long-term environmental costs. As such, we conclude that ecotoxicological testing is an opportunity for sediment management decision-making that warrants more attention and confidence in Europe.

     

Comparison of bean biochemical composition and beverage quality of Arabica hybrids involving Sudanese-Ethiopian origins with traditional varieties at various elevations in Central America

For buyers of Arabica coffee (Coffea arabica L.) in Central America, elevation and variety are important indicators of quality. We compared coffee produced by three types of varieties established in various trials at elevations ranging from 700-1600 m in three countries (El Salvador, Costa Rica and Honduras). Arabica hybrids resulting from crosses of Sudanese-Ethiopian origins with either traditional varieties or with introgressed lines derived from the hybrid of Timor (C. arabica x Coffea canephora Pierre ex Froehn) were compared with traditional cultivars (TC). Effects of elevation and variety on bean biochemical composition (caffeine, chlorogenic acid, trigonelline, fat and sucrose) were evaluated by predictive models based on calibration of near-infrared (NIR) spectra and by chemometric analysis of the global NIR spectrum. Beverage quality tests were performed by a panel of ten professional cup-tasters. Experiment 1 was carried out on the slopes of the Poas volcano (Costa Rica) with the traditional cultivar 'Caturra'. Experiment 2 compared the three varieties in a network of trials established in three countries of Central America. Significant linear regressions with elevation were observed in Experiment 1 with Caturra and in Experiment 2 for the traditional cultivars, and trends were established relating variation in biochemical compounds and cup quality to elevation. Convergence or divergence of the new hybrids in relation to these trends was observed. For the traditional cultivars, elevation had a significant effect on bean biochemical composition, with chlorogenic acid and fat concentrations increasing with increasing elevation. For the Arabica hybrids, elevation explained little of the variation in chlorogenic acid concentration and none of the variation in fat concentration. Nevertheless, Arabica hybrids had 10-20% higher fat concentrations than the traditional varieties at low elevations and similar fat concentrations at high elevations. The samples could be discriminated according to elevation based on NIR spectra; however, the spectra of the TC varieties were more strongly modified by elevation than the spectra of the hybrids. Nonetheless, this analysis confirmed homeostasis of the hybrids for which bean biochemical composition was less affected by elevation than that of the traditional varieties. The organoleptic evaluation, performed on samples originating from high elevations, showed no significant differences between Arabica hybrids and traditional cultivars. The new hybrid varieties with high beverage quality and productivity potential should act as a catalyst in increasing the economic viability of coffee agroforestry systems being developed in Central America.     

Comparison of the amounts of volatile compounds in French protected designation of origin virgin olive oils

Headspace solid-phase microextraction (HS-SPME) -gas chromatography using flame ionization detection and multivariate analysis were applied to the study of the specificity of protected designation of origin (PDO) virgin olive oils produced in a southern French region (Alpes-Maritimes) based on their volatile compounds. A total of 35 PDO olive oils from Nice, 6 commercial oils, and 12 other French PDO olive oils were analyzed. Recorded data were subjected to principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). The method developed here was able to perfectly distinguish different qualities of olive oils. Representative samples from each class obtained by chemometric treatment were analyzed by HS-SPME and GC-MS. PCA and SIMCA of chromatographic data were related to sensory analysis and led to a better understanding of the chemical features and observed sensory effects of olive oils.     

Hypothalamic deafferentation in prepuberal beef heifers: Effects of gonadotropin-releasing hormone and estradiol benzoate on luteinizing hormone secretion

Hypothalamic control of luteinizing hormone (LH) secretion was investigated in crossbred beef heifer calves by comparing anterior (AHD), posterior (PHD), and complete (CHD) hypothalamic deafferentation with sham operated controls (SOC). Heifers (n = 16) were fitted with an indwelling jugular catheter for 6 days before cranial surgery, and assigned randomly to treatments. Blood for radioimmunoassay of LH was collected sequentially at 15-min intervals during an 8-h period on days ? 1 before and day 6 after hypothalamic deafferentation or sham operation. On the day of surgery, blood samples were collected sequentially at 15-min intervals 2 h before induction of anesthesia and throughout surgery and early recovery. Seven months after hypothalamic deafferentation, all experimental and sham operated heifers were ovariectomized and treated with vegetable oil (i.m.) plus saline (i.v.), vegetable oil plus gonadotropin releasing hormone (GnRH), estradiol benzoate (EB, 1 mg) in vegetable oil. After ovariectomy basal plasma concentrations of LH increased (P < 0.01) compared with the low circulating hormone levels before ovariectomy. The amplitude of LH response to GnRH was greater (P < 0.01) in CHD and PHD when compared with SOC and AHD heifers. Injection of EB failed to induce a LH surge in CHD and PHD 900–1100 min later when compared with the robust response seen in SOC and AHD heifers. Injection of EB plus GnRH elicited LH release in all deafferentated and sham operated heifers. These results indicate a transient change in LH secretion after AHD or CHD in prepuberal heifers with intact ovaries. After OVX, the integrity of the neural connection of the posterior hypothalamus is required for EB-induced LH release in beef heifers.     

Proof-of-concept study: Evaluation of plasma and urinary electrolytes as markers of response to L-asparaginase therapy in dogs with high-grade lymphoma

Response to chemotherapy is one of the most important prognostic factors in dogs with lymphoma. The objective of this feasibility study was to evaluate if clinical responses to a specific cytotoxic agent (L-asparaginase) could be anticipated by measuring analyte concentrations in plasma and urine concentrations of lymphoma-bearing dogs. We hypothesized that potassium and phosphate concentrations in plasma and urine would be higher in dogs that completely responded to therapy. Plasma and urine samples of dogs with lymphoma were obtained before 12 and 24 hours after intramuscular L-asparaginase injections. Peripheral lymph node volumes were evaluated according to the Veterinary Cooperative Oncology Group standardized criteria. Plasma and urine electrolyte, calcium, phosphate, creatinine, urea, total protein, and albumin concentrations were measured, and the fractional excretions of each electrolyte were calculated. Statistical analyses compared complete vs partial responders using a linear regression model. Contrast analyses were also performed to differentiate the mean of each group, with adjustments made with the Benjamini-Hochberg procedure. Fourteen dogs were included, eight with complete responses, and six with partial responses. Plasma phosphate concentrations were significantly higher at 12 hours (P = .0003) and 24 hours (P = .009) after complete responses to therapy. This study demonstrates the potential use of plasma and urine analyte monitoring after chemotherapy induction. Plasma phosphate measurements represent a potential indicator of early responses to L-asparaginase therapy. Larger population studies are warranted to confirm these preliminary results.     

环保型可重复利用的海棉无土栽培基质的应用研究

用后处理和高成本是基质栽培的两大主要问题。岩棉已被公认为适用基质，但其主要问题是使用寿命短（最多2－3年）和每年产生大量的不可降解的废物。环境学家和政府部门调查研究显示，急需应用环保型可重复利用的无土栽培基质。本试验对新岩棉，椰子壳和已使用5年的海棉基质作了比较研究，旨在了解不同基质对温室番茄根限际环境、生长、发育和产量的影响，为海绵是否可作为番茄无土栽培适用于基质和提出有效的栽培管理措施提供理论依据。研究表明，海棉基质根际环境中EC和PH值比岩棉基质更稳定，每棉采果数，平均单果重，果实总重和和果实质量，海棉基质和岩棉基质无明显差异，但低于椰子壳基质，相对基传统的岩棉基质，已使用多年的海绵基质对番茄产量和质量无不良影响。海绵可作为温室番茄经济环保型基质。