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Nghiên cứu sự phân hủy lipid trong cá đông lạnh đã dẫn đến việc phát triển một phương pháp đơn giản và nhanh chóng để chiết xuất và tinh chế lipid từ các vật liệu sinh học. Toàn bộ quy trình có thể được thực hiện trong khoảng 10 phút; nó hiệu quả, có thể tái lập và không có sự thao tác gây hại. Mô ướt được đồng nhất hóa với hỗn hợp chloroform và methanol theo tỷ lệ sao cho hệ thống tan được hình thành với nước trong mô. Sau khi pha loãng với chloroform và nước, dịch đồng nhất được phân tách thành hai lớp, lớp chloroform chứa toàn bộ lipid và lớp methanol chứa tất cả các hợp chất không phải là lipid. Một chiết xuất lipid tinh khiết được thu nhận chỉ đơn giản bằng cách tách lớp chloroform. Phương pháp này đã được áp dụng cho cơ cá và có thể dễ dàng thích nghi để sử dụng với các mô khác.
Các nghiên cứu về phân hủy lipid trong cá đông lạnh đã dẫn đến việc phát triển một phương pháp đơn giản và nhanh chóng để chiết xuất và tinh lọc lipid từ các vật liệu sinh học. Toàn bộ quy trình có thể được thực hiện trong khoảng 10 phút; nó hiệu quả, có thể tái sản xuất và không gây ra các thao tác gây hại. Mô ướt được đồng hóa với hỗn hợp chloroform và methanol theo tỷ lệ đảm bảo hệ thống tạo thành hòa tan với nước trong mô. Việc pha loãng với chloroform và nước tách đồng hóa thành hai lớp, lớp chloroform chứa tất cả các lipid và lớp methanolic chứa tất cả các phi lipid. Một chiết xuất lipid tinh khiết được thu được chỉ bằng cách cô lập lớp chloroform. Phương pháp này đã được áp dụng cho cơ cá và có thể dễ dàng điều chỉnh để sử dụng với các mô khác.
The spectrophotometric procedure proposed by Schwert and Takenaka for the assay of chymotrypsin and trypsin has been modified and extended to include the application to N-benzoyl-L-tyrosine ethyl ester and α-p-toluenesulphonyl-L-arginine methyl ester. The greater degree of sensitivity and specificity thus achieved permits the determination of traces of chymotrypsin in the presence of relatively large amounts of trypsin and vice versa. A similar spectrophotometric procedure for the assay of thrombin is described.
It is characteristic of arteries that they do not obey Hooke's law, but resist further stretch more strongly, the more they are stretched. It appears that this might be due to the combination of elastin fibers in the elastic laminae, with the much less distensible collagenous libers in the media and adventitia, more and more of which reach their 'unstretched length' as distension is increased. This has been verified on human iliac arteries, from autopsy, by comparing the 'elastic diagrams' (tension vs. circumference) before and after differential digestion of collagen by formic acid, and digestion of elastin by crude trypsin (containing an elastase). This proved that the resistance to stretch at low pressures was almost entirely due to elastin fibers, that at physiological pressures due to both collagenous and elastin fibers, but dominantly to collagen, and that at high pressures almost entirely due to collagenous fibers. In future work on the effect of age on the elasticity of iliac arteries, the initial slope of the elastic diagram can be taken as an index of the state, or number, of the elastin fibers, and the final slope as an index of the state, or number, of collagenous fibers.
The various long-range forces which are effective between molecules in their electronic ground states are examined. Orders of magnitude are given for those forces which should occur in the interaction of lipide and protein chains. It is found that electrostatic forces should be responsible for bringing and holding together protein and lipide components, but London – Van der Waals dispersion forces are probably of paramount importance in maintaining the lipide chains together in micelles or double layers.Special attention is drawn to the dispersion forces and to the conditions under which these forces are locally additive; one can calculate accurate values of the dispersion energy of interaction between saturated hydrocarbon chains at short distances (a few angstroms apart) by adding all the bond–bond interactions. A general expression is given for the dispersion energy between two parallel and opposed chains built out of identical units, and numerical values are given for the case of closely packed hydrocarbon chains.The total attraction energy is extremely sensitive to the intermolecular distance. The role of this "distance-specificity" in interactions involving unsaturated fatty acid chains and its contribution to the stability of lipoproteins is briefly examined.
A new blood steroid, 11-ketotestosterone, has been isolated from postspawned male sockeye salmon. The steroid was identified by chromatography, infrared spectra, chemical transformation, and synthesis. This steroid is present at a concentration of 12 μg/100 ml of plasma and probably was reported as corticosterone by other investigators. Evidence is presented in support of the occurrence of corticosterone at a very low concentration in salmon plasma. The concentrations of cortisol, cortisone, corticosterone, and total Porter–Silber positive steroids were determined in large plasma samples taken from postspawned fish of both sexes.
Cortisone, cortisol, and 17-hydroxyprogesterone were isolated from the plasma of prespawning Fraser River sockeye salmon. The female plasma contained double the concentration of cortisone and cortisol found in male plasma, 41 μg and 26 μg/100 ml respectively as compared with 22 μg and 11 μg/100 ml.Corticosterone is probably present at a very low concentration and neither 11-desoxycorticosterone nor aldosterone was detected in the plasma from approximately 100 fish. Cortisone, cortisol, and total 17-hydroxysteroids were quantitatively determined in plasma samples obtained from two pure races of sockeye captured at various stages of sexual maturity. The combined concentration of cortisone and cortisol which, at the mouth of the river was three times that of the normal human, increased to as high as 17 times this level following spawning. The results are discussed in relation to the death of the fish.
The influence of serum and tissue homogenates on the mitotic rate of regenerating liver was tested. The following fractions were injected into Sprague–Dawley rats 24 hours after partial hepatectomy: (a) serum from normal 290–340 g. rats; (b) serum from rats 24 or 72 hours following partial hepatectomy; (c) liver homogenates from normal 290–340 g. rats; (d) regenerating liver homogenates (24 hours after partial hepatectomy); and, as controls, (e) brain homogenates representing non-mitotic tissues; (f) testes homogenates representing mitotically active tissues. Serum and liver from adult animals inhibit the onset of mitosis. Serum and regenerating liver from partially hepatectomized rats, as well as heterologous tissue, show no retarding effect.The results suggest the presence of an organ-specific inhibitor of mitosis in the serum and liver of adult animals.
Albumin palmitate-1-C14complex was infused at a constant rate through a carotid cannula (inserted 5–7 days earlier) into otherwise intact non-fasted rats in environments at 30° or 6 °C, after acclimation to 30° or 6 °C. At 6 °C, both warm- and cold-acclimated rats similarly exhaled as CI4O2a larger proportion of the injected C14and gave lower terminal amounts of C14in the extracted free fatty acids (F.F.A.) of plasma than at 30 °C. These results indicate that plasma F.F.A. serve as substrate for cold-thermogenesis. Also, increased turnover and oxidation of F.F.A. are not always inversely related to carbohydrate utilization but may be increased under conditions which result in concomitantly higher rates of turnover and oxidation of glucose.