The Impact of Natural Deep Eutectic Solvents and Extraction Method on the Co-Extraction of Trace Metals from Fucus vesiculosus

In recent years, natural deep eutectic solvents (NADES) have been widely investigated for the extraction of food and medicinal plants as well as seaweeds. However, the ability of NADES for trace elements co-extraction from natural sources is not well investigated. The aim of this study was to investigate the ability of common NADES for trace elements co-extraction from Fucus vesiculosus. All of the tested NADES did not recover As and Co (concentration <LOQ). Moreover, all of the tested NADES provided a low recovery (<9%) of Ba, Ca, Fe, Mg, Mn, Sr, and Zn. The method of extraction had not shown a statistically significant effect on the co-extraction of all elements (excluding Ba and Ca). In contrast, the water content in NADES was significantly affected on the recovery of Ba, Ca, Mg, Mn, Sr, and Zn. The recovery of Al and Cr was relatively high and considerably varied (from 1.5 to 59.9%). NADES comprising lactic acid:glucose:H₂O (5:3:1) provided the lowest contents of all elements, and the highest extracted amounts were obtained employing water contents of 60–80%. The calculated daily intake of all the elements contained in NADES extracts were less than the daily dose risk estimators. The hazard quotients, hazard indexes, and carcinogenic risk calculated for all trace elements and their combination were considerably less than 1. This evidences no health risk, and carcinogenic risk after topical application of all studied NADES. For the first time, the results of the current study demonstrated that NADES extracts of F. vesiculosus contain a lower amount of trace metals and are safer than the extracts obtained with water and 70% acetone. This indicates a significant advantage for NADES compared with the other solvents.     

Amyloodinium ocellatum (Brown, 1931) (Dinoflagellida) infestations in cultured marine fish at Eilat, Red Sea: epizootiology and pathology

Abstract. Since 1977, repeated outbreaks of infestation by Amyloodinium ocellatum (Dinoflagellida) in cultured gilthead bream Sparus aurata L. and seabass Dicen-trarchus labrax (L.) resulted in sporadic and mass mortalities. Fingerlings and yearlings as well as breeders were affected and, since 1978, larval and post-larval S. aurata in the hatchery. Infestations in juvenile and breeder fish were located predominantly on the gills and mucosal integument but in larval fish only the skin rather than the gills was infested. Histopathological changes of the infested gills are described. Vacuolar degeneration of the cells penetrated by the parasites' rhizoids was evident at the site of attachment and cloudy swelling was apparent in the surrounding epithelial cells. In heavy infestations the entire epithelium of the gill filaments underwent hyperplasia with consequent fusion of the lamellae. Where hyperplasia was extensive the cells gradually degenerated while the inner epithelial layer showed distinct spongiosis and in some cases completely disintegrated. All heavily infested gills lacked mucous cells.     

Regrowth of ryegrass swards subject to different cutting regimes and stocking densities

A cutting experiment was carried out on a sward of S23 perennial ryegrass to study the effect of different defoliation regimes on regrowth and the factors affecting regrowth. The defoliation frequencies and intensities encompassed the range commonly found on continuously stocked pastures. The defoliation regimes produced swards of contrasting growth form with regrowth characteristics which differed in respect of senescence loss, fall in water-soluble carbohydrate concentration, residual leaf area index, photosynthesis per unit leaf area index and photosynthesis per unit area of land. Regrowth was most closely related to the latter. These results were used to interpret data for net canopy photosynthesis of continuously grazed pastures.     

Charcoal column/thin layer chromatographic method for high fructose corn sirup and spectrophotometric method for hydroxymethylfurfural in honey: collaborative studies.

A new spectrophotometric method is described for determining hydroxymethylfurfural in honey in which interfering background absorption of honey is corrected for by use of a bisulfite-treated sample as blank. Two procedures for detecting high-fructose corn sirup (HFCS) in honey were also tested. In one, charcoal column pretreatment is used to concentrate trace oligosaccharides, followed by thin layer chromatography to differentiate those of HFCS from those of honey. The other method depends on measurement of the isomaltose/maltose ratio by gas-liquid chromatography. The charcoal/thin layer chromatographic method for HFCS has been adopted official first action. The bisulfite method for hydroxymethylfurfural has been adopted interim first action.     

The effect of propionic acid on the storage losses of hay

Storage losses in moist hay treated with propionic acid were compared with those occurring in untreated moist hay in two experiments and with field-cured hay in three experiments. Dry matter losses in treated hays ranged from 41 to 8.6% and from 1.7 to 12.6% in untreated hays. Digestible organic matter losses in both treated and untreated hays were generally greater than dry matter losses. Only in one experiment did propionic acid application significantly reduce nutrient losses in moist hays. Nutrient losses, and water-soluble carbohydrate losses in particular, were shown to be correlated with maximum and cumulative bale temperatures during storage in two of the experiments. The rise in hale temperatures during storage was reduced in all three experiments, to a greater or lesser extent, by application of the additive. Loss of propionic acid from the hay during and after application was very large. In the three experiments 86.2, 85.3 and 85.6% of the acid applied was lost by the end of the storage period. Acid distribution studies indicated that variation in acid concentration within bales was as great as between bales. It was concluded that more research is needed into applicator design and position on the baler and into alternative application methods if the benefits of propionic acid as a moist hay preservative are to be fully exploited.     

The effect of delayed autumn harvest on the survival of varieties of perennial ryegrass

The reactions of five early and five late varieties of perennial ryegrass to stimulation of bulky autumn growth and deferment of harvesting were compared in terms of spring growth and subsequent recovery during three winters. Winterkill was marked in 1971–72, particularly when harvesting was deferred to late November, in early varieties S24 and Presto Pajbjerg and in the late variety S23. Least affected among early varieties were Premo and Barvestra (tetraploid) and among late varieties, Perma and Barpastra (tetraploid). All varieties showed rapid recovery. The results are discussed in terms of the significance of winterkill, and the effects of age of sward, variety susceptibility and deferment of autumn defoliation. It is concluded that the form of winterkill which occurs in the west of Scotland can have serious consequences to farm productivity in severe winters. Autumn growth left standing into November can also lead to winterkill. Under good management, varietal differences are unimportant. In a severe winter, no varieties of perennial ryegrass are reliable.     

Removal of mineral nutrients by red clover varieties

K, P, Ca and Mg contents and uptakes are reported from total herbage of plots sown with six varieties of red clover harvested three times a year for 3 years. K, P and Mg contents were above those reported as critical for growth; values for Ca were lower than quoted ranges which suggested that growth might have been affected by either deficiency of Ca or low pH. Hungaropoly was characterized by relatively low K and P and high Ca contents. Maximum uptakes in red clover total herbages over 3 years were 1198 kg ha^?1 K (Hera), 112 kg ha^?1 P (Hera), 494 kg ha^?1 Ca (Hungaropoly) and 104 kg ha^?1 Mg (Mars). Results were compared with those found for S101 perennial ryegrass, harvested on a similar system and receiving similar fertilization with uptakes of 759 kg ha^?1 K, 100 kg ha^?1 P, 200 kg ha^?1 Ca and 46 kg ha^?1 Mg, by expressing accumulating uptakes and inputs as linear regression equations. The better varieties of red clover, Hera, Hungaropoly, Mars and S123 show rates of DM accumulation similar to S101 perennial ryegrass and similar uptake rates of K and P but higher rates of uptake of Ca and Mg. The levels of application of K and P used in the experiment seem to be more than adequate but attention to the Ca status may be required to sustain high-yielding red clover swards.     

Some observations on plant lectins and Rhizobium specificity

The ability of fluorescein isothiocyanate (FITC) labelled lectins extracted from the legumes Aspalathus linearis, Glycine max, Lotononis bainesii, Phaseolus vulgaris and Pisum sativum, respectively, to react with strains of various Rhizobium spp. was studied. With the exception of six out of ten strains of R. phaseoli and two out of ten strains of R. japonicum, none of the Rhizobium strains tested were able to bind lectin from their normal host plants. Many strains of R. leguminosarum, R. trifolii and R. phaseoli bound each of the plant lectins studied with the exception of the P. sativum lectin. This lectin was only bound by two strains of R. meliloti and a slow-growing strain isolated from Macroptilium atropurpureum. These results do not support suggestions by other workers that plant lectins play an important role in Rhizobium specificity.     

INTERACTIONS BETWEEN FIRST AND SECOND APPLICATIONS OF FERTILIZER NITROGEN AND IMPLICATIONS IN EFFICIENCY OF NITROGEN USE

DM yield and N uptake data are presented from primary growth and two successive regrowths of perennial ryegrass treated with combinations of three N treatments for the primary growth viz. 0, 50 and 100 kg N/ha (PN) and four N treatments applied for the second growths, viz. 0, 33, 66 and 100 kg N/ha (SN). Primary growth gave a response of 24·2 kg DM/kg applied N to PN50 with only a further l±0 kg DM/kg applied N from the second PN increment. A significant interaction between PN and SN treatments was shown in second growth. The residual DM response to PN was highest at SN0 and reduced as the level of SN was raised. Substantially greater residual responses to PN treatments were shown in the third growth. Third growth DM responses to SN treatments were high. High apparent recovery of fertilizer N reached 111% of primary N where SN66 followed PN50. High available soil N is partly responsible for both high apparent recovery of N and high DM response. The latter appears to be associated with inclusion of growths given no fertilizer N so that the full residual effects of fertilizer N and ‘priming’ of available soil N can be realised.