ALBERT

Notes: Results of the analysis for dry-matter, nitrogen and major base content of 9 silage effluents obtained from farm silos and 3 effluents from experimental tower silos are presented. The mean values obtained for the principal plant nutrients in the 12 effluents examined were 0·19% N, 0·037% P and 0·38% K. The results indicate that effluents may be a useful source of plant nutrients, particularly when undiluted with rainwater, and that, in general, silage effluents appear to be superior to liquid manure in manurial value.

Notes: The oral introduction of 0·5 g histamine as the diphosphate into the rumen of sheep produced no effect on the physiological condition of the animals. The feeding of histamine, as the dihydrochloride, in levels up to 1 g/day to sheep on silage diets did not affect the dry-matter intake.

Notes: Biological spoilage of non-carbonated orange drink is caused mainly by yeasts that are not inhibited by preservatives at permitted levels. A stain that distinguishes living from dead yeast cells was used to develop a technique that detected yeast growth within 24–36 hr of the addition of one viable yeast cell per 190 ml of pasteurized orange drink.

Notes: Zusammenfassung Die Wirkung von Vitamin K1 auf mit Coumarin behandelte Kaninchen wird durch 2-Chloro-3-Phytyl-1:4-Naphthochinon gehemmt.

Notes: Zusammenfassung Der Bericht umfasst die Analogie zwischen Elektrostatik und Diffusion und die experimentelle Bestimmung der Kapazität von verschiedenen Formen von Eiskristallen.

Notes: Summary In the present study we followed with the electron microscope the changes which the lipids undergo during their transport between the blood and the fat cells in both impletion and depletion of the fat depots. Impletion was studied in tissues from mice on the first or second day after birth, when the storage of fat begins, and from newborn mice and young rats that were refed after periods of starvation. Fat depots in the state of depletion were taken from the starving animals. During impletion the chylomicrons were found to be attached to the endothelium of the capillaries in the fat organs, where they seem to break up into smaller and less electron-dense particles. The absorption of the lipids by the capillary endothelial cells could not be observed, since no osmiophilic material was found within the capillary wall. No such material was present within the interstitial connective tissue between capillaries and fat cell. When the lipids enter the fat cell they again become observable as osmiophilic granules. These lipomicrons seem to represent the absorbed lipid material in transit between the surface of the fat cells and the fat droplets in the cells. Although dispersed throughout the cytoplasm, the lipomicrons were often accumulated at, and attached to, the surface of the growing fat droplets. They lost their identity when they were incorporated into the homogeneous material of the fat droplets. According to these observations, several steps were distinguished during impletion and were localized at the surface of the capillaries, at the plasma membrane of the fat cells, and at the surface of the fat droplet. The findings were discussed in the light of the physiological and biochemical literature concerning the clearance of the chylomicrons from the blood. The static pictures of the fat cells in the depleting state are very similar to those of the impleting cells. Lipomicrons are present, and they seem to emerge from the surface of the diminishing fat droplets. Also in these cells they seem to represent the lipids in transit, but in the reverse direction. At the cell border they disappear, and no osmiophilic material could be discovered within the interstitial tissue or within the capillary wall. Occasionally osmiophilic globules were found within the capillaries of the depleting fat organs, but they did not show the same relationship to the endothelium as the chylomicrons. We concluded from the similarity between the static pictures of depleting and impleting cells that the processes distinguished and localized during impletion are reversed when the cell releases fat. If this is correct, our pictures illustrate the lability of the fat organs, which respond to changing conditions by reversing the processes involved in their twofold activity of absorbing and releasing fat. The lipomicron pool in the fat cell seems to represent the lipids most immediately available either for storage or for release under ordinary nutritional conditions, where such drastic changes as in our experimental material do not occur. During both impletion and depletion the mitochondria were found to be profoundly changed. It is believed that these changes are mainly due to an infiltration of the mitochondria by lipomicrons. However, these observations do not permit us to draw conclusions as to the function of the mitochondria in the storage or release of fat.

Notes: Summary The oedematous changes in the cerebral cortex of rats after acute irradiation are described. The importance of these changes in the over-all injury is discussed. Swelling and rupture of clear glial cells without expansion of the extracellular space are seen during the early phases of injury. Not all of the clear glia become swollen, but those that do eventually undergo complete dissolution, initiating small foci of severe damage. The necrosis that ultimately encompasses the entire irradiated field may spread from these initial sites of injury. Clear glial cells that do not undergo swelling show an unusual type of reaction before they become necrotic.

Notes: Summary The main purpose of this paper was to investigate with the electron microscope the structural relationship between the fat cell and the surrounding connective tissue under various functional conditions and thereby to solve questions not decided in the past which concern the “membrane” of the fat-cell. Outside the well defined plasma membrane two layers were observed, one of lesser electron density next to the plasma membrane and another denser line which separates the former from the connective tissue ground substance. Fundamentally this three-layered “surface membrane complex” (Robertson) is the same as described by numerous authors in other cells bordering on connective tissue. However, the changes occurring in the surface membrane complex during depletion of fat cells are of special interest. The numerous long processes formed by the cell during the loss of fat in starvation are retracted in extreme depletion. At this time a pericellular space opens between the outer lamella and the plasma membrane. While the less dense material apparently becomes liquified the outer lamella of the surface membrane complex remains in contact with the connective tissue ground substance. These observations made it possible to interpret the surface membrane structures of the fat-cell as consisting, beside the plasma membrane, of a material derived from the ground substance, which is analogous to Robertson's “gap substance” at the surface of the Schwann cell, and of a “limiting membrane” toward the ground substance. The nature and possible derivation of the extracellular layers are discussed and the general functional significance of the surface membrane complex is emphasized. These considerations support the repeatedly raised objection against the use of the histological term basement membrane for the submicroscopic structures. During the depletion of the fat cell intensive micropinocytosis occurs regularly in the plasma membrane. It is suggested that the pinching off of numerous pockets may effect the elimination of membrane material in conjunction with the decrease in the surface area which has been found to take place in extreme depletion of the fat cell.

Notes: Summary Mustard plants were grown in nutrient solutions containing 3 levels of Fe, 4 ratios of K/Ca, and 2 ratios of P/N, the iron in each experiment being applied as the chloride, the ethylene diamine tetra-acetic acid or the ethylene N,N'-bis (2-o-hydroxyphenyl) glycine chelate. It was found that increases in the iron level decrease the values of both P/Fe and K/Ca as estimated on the leaf ash when iron was an element limiting the growth of the plants.