Supersaturation of soil solutions with respect to gypsum

The products of activities of calcium and sulphate were calculated for solutions of 75 glasshouse soils. The majority of these products was found to be higher than the solubility product of gypsum, thus indicating that these soil solutions were possibly supersaturated. In another investigation, soil solutions were examined to determine whether such high activity products could be really attributed to supersaturation. By means of ultracentrifuging of solutions of glasshouse soils, it could be established that the solutions were practically free of sulphate-bearing colloidal particles. Some solutions contained calcium-bearing colloidal particles, but the quantities of calcium contained in these particles were too small to substantially influence the calcium activity. Addition of gypsum crystals to soil solutions led to crystallization of so much calcium and sulphate that the products of the activities of calcium and sulphate dropped from values that can be listed as high to values approaching the solubility product of gypsum. The results obtained demonstrate the occurrence of supersaturation of soil solutions with respect to gypsum. It is further postulated that the presence of humic substances in the soil solution is responsible for this supersaturation. The possible occurrence of supersaturation with respect to gypsum in soils other than glasshouse soils is discussed.     

1H- and13C-NMR spectroscopic studies of lipid extracts of the red algaGracilaria longa

Lipid extracts of the red algaGracilaria longa were studied by¹H- and¹³C-NMR spectroscopy. Peaks in the¹³C-NMR spectra attributable to sterols, chlorophylls and carotenoids allowed free and acylated cholesterol, chlorophylla and lutein to be identified as the most abundant components of these classes. A content of 0.5 ± 0.1 μmoles of total cholesterol/g wet alga was estimated from the¹H-NMR spectrum, which also allowed the determination of the phosphatidylcholine/total lipid molar ratio (9.5 ± 0.5%). The¹³C-NMR spectroscopic experiments provided information on the position of the double bonds on the fatty acid residues. A comparison between NMR spectra of lipid extracts obtained for wet and dried alga showed that the alga undergoes both a dramatic peroxidation and some glycolipid degradation during the drying process.     

Structure and polymorphism of bipolar isopranyl ether lipids from archaebacteria

We describe in this work the structure and polymorphism of a variety of lipids extracted from Sulfolobus solfataricus, an extreme thermoacidophilic archaebacterium growing at about 85 °C and pH 2. These lipids are quite different from the usual fatty acid lipids of eukaryotes and prokaryotes: each molecule consists of two C₄₀ ω-ω′ biphytanyl residues (with 0 to 4 cyclopentane groups per residue), ether linked at both ends to two (variably substituted) glycerol or nonitol groups. Four lipid preparations were studied; the total and the polar lipid extracts, and two hydrolytic fractions, the symmetric glycerol dialkyl glycerol tetraether and the asymmetric glycerol dialkyl nonitol tetraether, as a function of water content and temperature, using X-ray scattering techniques. The main conclusions from the study of the four lipid preparations can be summarized as follows. (1) As with other lipids, a remarkable number and variety of phases are observed over a temperature-concentration range close to “physiological” conditions. The possibility is discussed that this polymorphism reflects a fundamental property of lipids, closely related to their physiological rôle. (2) As in other lipids, two types of chain conformations are observed: a disordered one (type α) at high temperature; at lower temperature, a more ordered packing of stiff chains, all parallel to each other (type β′). At temperatures and degrees of hydration approaching the conditions prevailing in the living cell, the conformation is of type α. (3) In all the phases with chains in the α conformation, the unsubstituted glycerol headgroups, whose concentration is high in these lipids, segregate in the hydrocarbon matrix, away from the other polar groups. This property may have interesting biological consequences: for example, the chains of a fraction of the bipolar lipid molecules can span hydrocarbon gaps as wide as 75 Å. (4) Two cubic phases are observed in the total and the polar lipid extracts, which display a remarkable degree of metastability, most unusual in lipid phase transitions involving structures with chains in the α conformation. This phenomenon can be explained by the interplay of the physical structure of the cubic phases (the two contain two intertwined and unconnected three-dimensional networks of rods) and the chemical structure of the lipid molecules: the two headgroups of most molecules being anchored on each of the two networks of rods, the migration of the lipid molecules is hindered by the two independent diffusion processes and by the entanglement of the chains. The possibility is discussed that this phenomenon may reflect an evolutionary response to a challenge of the natural habitat of these archaebacteria.     

Flavonoid glycosides of the roots of Glycyrrhiza uralensis

The structure of a flavanone glycoside from the roots of Glycyrrhiza uralensis has been confirmed as 4′-O-[β-d-apio-d-furanosyl-(1 → 2)-β-d-glucopyranosyl]liquiritigenin. In addition, two known flavonoid glucosides, ononin (a minor component) and liquiritin (a major component), were isolated from the same extract.     

Follicular dynamics in mares treated with an equine pituitary extract

The follicular dynamics of 112 mares treated with an equine pituitary extract were studied. Follicles >10 mm in diameter at day 15 post-ovulation appeared to represent the follicles which were induced with pituitary extract to grow and ovulate. This was shown by the greater number of >10 mm follicles in mares which subsequently had higher ovulation rates and by the subsequent decrease in number of small follicles (<20 mm) which corresponded with the increase in number of large follicles (>/=20 mm). The difference in diameter (mm) between the largest and second largest follicle on day 15 post-ovulation was greater (P<0.05) for extract-treated mares which subsequently had single ovulations than for extract-treated mares which subsequently had multiple ovulations (7.7 +/-1.5 vs 2.8 +/-0.6). The observed ratio of bilateral to unilateral multiple ovulations was not different (P>0.1) from the expected ratio which was calculated on the assumption that side of ovulation occurred independently (59:19 vs 62:16, observed vs expected).     

Prevention of aortic lesions and hyperlipidaemia by alfalfa seed extract in cholesterol fed rabbit

Extract of alfalfa seed (ethanolic 50 % v/v) prevents the development of plaque formation and hyperlipidaemia in cholesterol fed rabbits. It inhibits the elevation of serum total cholesterol, triglycerides, phospholipids, LDL-cholesterol and total cholesterol/phospholipid ratio, while HDL-cholesterol/total cholesterol ratio increases, which is associated with a reduced incidence of atherosclerosis. Further reduction in total cholesterol and phospholipid contents of liver and heart muscle are suggestive of a beneficial role of the seed extract. The possible mechanisms of action are discussed.     

Philomena oncorhynchi: Effect of hormones on maturation in anadromous sockeye, Oncorhynchus nerka

Adult sockeye salmon, Oncorhynchus nerka (Walbaum), treated with salmon pituitary extract in July survived for up to 47 days and developed nuptial colours in both male and female fish during this period, whereas no such characteristics appeared in untreated control fish. Furthermore, results showed that 20 of 50 adult female Philomena oncorhynchi recovered from the 15 treated fish contained fully developed tailed larvae in the uterus as compared with only one of 44 female P. oncorhynchi from 31 untreated control fish. None of 51 worms from 13 stilboestrol treated adult sockeye showed development in utero beyond an elongated embryo, nor did the host fish develop nuptial colours. P. oncorhynchi and its immature sockeye host (approx. 1 year prior to spawning) remained unaffected by any of three separate hormone treatment experiments using injection of salmon pituitary extract, injection of 17-β-estradiol, and stilboestrol mixed in the food.     

Further purification of a fibroblast growth factor-like factor from chick embryo extract by heparin-affinity chromatography

Summary A mitogenic factor which promotes quail myoblast proliferation has been purified some 10⁵-fold from chick embryo extract by a combination of cation-exchange chromatography and heparin-affinity chromatography. The factor is eluted from heparin-Sepharose with 2M NaCl and is a single-chain polypeptide with an apparent molecular weight of 15000 to 17000. It is active at subnanogram level in triggering the proliferation and thereby delaying temporarily fusion of myoblasts. It also stimulates the proliferation of quail fibroblasts in a similar effective concentration range. For both myoblasts and fibroblasts the dose-response to the factor is quantitatively and qualitatively comparable with that of bovine pituitary fibroblast growth factor. These observations strongly suggest that the factor very probably corresponds to chicken fibroblast growth factor or to a closely related molecule(s) and that it is possibly involved in the regulation of myogenesis. This work was partly supported by a grant from the National Center of Neurology and Psychiatry (NCNP grant 86-01) of the Ministry of Health and Welfare, Japan.     

利用腺病毒DNA与爪蟾卵提取物在非细胞体系中重构细胞核(简报)

1983年,Lohka和Masui首先报道,用精子染色质与卵提取物一起温育,可以组装成具有典型结构的细胞核。这种核不仅具有合成DNA的能力,而且还能进入M期。同年,     

视网膜神经节细胞的纯化和体外存活

我们用特异性抗体Thy1.1结合尼龙筛方法分离和纯化新生大鼠视网膜神经节细胞,比较顶盖提取液对这些纯化细胞的作用。预先以快蓝(fast blue,FB)逆行标记的视网膜细胞悬液,接种在包被了Thy1.1抗体的培养皿上30分钟,冲洗未粘附的细胞,显微镜下计数粘附细胞中FB标记的视网膜神经节细胞纯度的百分比,最高为95%。用孔径15μm尼龙筛方法分离的纯度仅为60±5%。上述两种方法纯化的视网膜神经节细胞,仅在有顶盖提取液存在时,细胞存活并生长活跃,胞体大且有突起伸出。MTT微量比色法测定培养24小时纯化细胞存活的光密度(OD)值,显示以Thy1.1特异性抗体纯化的细胞,其OD值比值(+Te/-Te)是12.3(0.111/0.009);以尼龙筛纯化的OD值比值(+Te/-Te)是6.4(0.102/0.016);未经纯化的OD值比值(+Te/-Te)是3.8(0.095/0.025)。在上述三组中,加Te与无Te细胞生存的OD值比较,相差均非常显著(P<0.01)。结论:在纯化的视网膜神经节细胞的培养中,由于排除了其他细胞所引起的非特异性反应,神经节细胞能够更直接地反映顶盖提取液的生物效应;视网膜神经节细胞纯度越高,其作用越显著。