Sequence analysis of five new field isolates demonstrates that the chain length of potato spindle tuber viroid (PSTVd) is not strictly conserved but as variable as in other viroids

The sequence analysis of five new field isolates of potato spindle tuber viroid (PSTVd) of different virulence revealed that the lengthof their RNA chain is not strictly conserved to 359 nucleotides (nts), as one could have inferred from the previously sequenced PSTVd strains. It was now found that the chain length is strain-specific like in the case of practically all other viroids, and that it may vary, so far, between 356 and 360 nts. Taking our previously sequenced and least virulent mild strain PSTVd KF6-M as standard, the new mild strains PSTVd WA-M and PSTVd F-M differ from it by one or two nts. The new intermediate-severe strains PSTVd F-IS and PSTV-F 88-IS differ from the standard mild strain by eight and nine nts, respectively, whereas the new severe-lethal strain PSTVd F-SL differes in seven nts. Most of these mutations are located within the virulence-modulating (VM) region and within the variable region (VR), and only in two strains a single mutation is found in the right terminal domain.     

Consequences of 6 weeks of strength training on red cell O2 transport and iron status

Effects of endurance training on O2 transport and on iron status are well documented in the literature. Only a few data are available concerning the consequences of strenuous anaerobic muscular exercise on red cell function. This study was performed to test the influence of strength training alone on parameters of red cell O2 transport and iron status. Twelve healthy untrained males participated in a strength-training programme of 2-h sessions four times a week lasting 6 weeks. After 6 weeks a small but significant reduction of haemoglobin (Hb; -5.4 g.l-1) was found (p less than 0.05). Mean red cell volume did not change, but a pronounced decrease of mean cell Hb concentration (from 329.2 g.l-1, SE 2.5 to 309.8 g.l-1, SE 1.2; p less than 0.001) and mean corpuscular Hb (from 29.6 pg, SE 0.4 to 27.7 pg, SE 0.3; p less than 0.01) was observed. Serum ferritin decreased significantly by 35% (p less than 0.01); transferrin, serum iron and iron saturation of transferrin were unaltered. Serum haptoglobin concentration was diminished significantly by 30.5% (p less than 0.01). The reticulocyte count had already increased after 3 weeks of training (p less than 0.05) and remained elevated during the following weeks. Strength training had no significant influence on the O2 partial pressure at which Hb under standard conditions was 50% saturated, red cell 2,3-diphosphoglycerate and ATP concentration as well as on erythrocytic glutamate-oxalacetate transaminase activity. The data demonstrate that mechanical stress of red cells due to the activation of large muscle masses led to increased intravascular haemolysis, accompanied by a slightly elevated erythropoiesis, which had no detectable influence on Hb-O2 affinity. Training caused an initial depletion of body iron stores (prelatent iron deficiency). Although Hb had decreased by the end of the training phase a true "sports anaemia" could not be detected.     

Hepatic glucagon clearance during insulin induced hypoglycemia

Studies concerning the importance of glucagon secretion in hypoglycemic counterregulation have assumed that peripheral levels of glucagon are representative of rates of pancreatic glucagon secretion. The measurement of peripheral levels of this hormone, however, may be a poor reflection of secretion rates because of glucagon's metabolism by the liver. Therefore, in order to understand the relationship between pancreatic glucagon secretion and levels of glucagon in the peripheral blood during hypoglycemia, we evaluated hepatic glucagon metabolism during insulin induced hypoglycemia. Four dogs received an insulin infusion to produce glucose levels less than 50 mg/dl for 45 minutes. In response to this, the delivery of glucagon to the liver increased from 36.7 +/- 5.9 ng/min in the baseline to 322.6 +/- 6.3 ng/min during hypoglycemia. Hepatic glucagon uptake increased proportionally from 13.6 +/- 7.2 ng/min to 103.1 +/- 28.3 ng/min and the percentage of delivered hormone that was extracted did not change (30.8 +/- 13.8% vs 32.9 +/- 11.6%). The absolute amount of glucagon metabolized by the liver was dependent on the rate of delivery and was not directly affected by plasma glucose level per se. To directly study the effect of hypoglycemia on hepatic glucagon metabolism, five dogs were given an exogenous infusion of somatostatin followed by an infusion of glucagon and then administered insulin to produce hypoglycemia. The percent of glucagon extracted by the liver (19.5 +/- 4.9% and 21.3 +/- 6.4%) was not affected by a fall in the plasma glucose level.(ABSTRACT TRUNCATED AT 250 WORDS)     

Accumulation of Maltose during Photosynthesis in Protoplasts Isolated from Spinach Leaves Treated with Mannose

When mannose was included in the enzyme incubation medium during the preparation of protoplasts from leaves of spinach, maltose was an early product of protoplast photosynthesis and, after 12 minutes, accounted for up to 15% of the ¹⁴C incorporated from ¹⁴CO₂. Maltose was not detected in protoplasts prepared in the normal enzyme medium. Rapid separation of cytoplasm and chloroplasts following exposure to ¹⁴CO₂ showed that maltose was present in both fractions. Direct measurements of [¹⁴C]maltose uptake indicated transport across the chloroplast envelope at rates similar to the transport of glucose. The source of maltose and site of its initial formation are discussed.     

Ultrastructure of spermatozoa of Peregrinus maidis (Homoptera,Delphacidae)

Summary The spermatozoa of Peregrinus maidis Ashm. are thread-like, approximately 650 long and 1 wide including the head (approximately 28 ).The main part of the spermatozoa consists of two mitochondria derivatives, a central body between them, the axial filament complex, and a newly found element consisting of two wing-shaped bodies. Each mitochondrion derivative shows a peripheral and an inner part. The peripheral part is formed by cristae arranged perpendicularly to the long axis of the spermatozoon. The cristae are approximately 70 Å wide. The dense layers between them measure approximately 280 Å. The inner part of the mitochondrion derivative shows a crystalline array, formed by sub-units of approximately 100 Å diameter. The wing-shaped bodies consist of tubular elements.The head has an elongated nucleus with an electron transparent space inside. At the anterior end of the nucleus lies a tapered acrosome. This appears fibrous and parts of the acrosome fibers seem to run along the nucleus. Acknowledgements. The authors wish to thank Dr. G. H. Bergold for suggestions and support, Drs. J. André, D. W. Fawcett, P. Maillet and G. F. Meyer for very helpful discussion. They are also grateful to Mr. O. Suárez for assistance in the preparation of the organs of P. maidis and to Mrs. M. de Pingarrón for technical assistance.     

Beiträge zur Verbreitung und Ökologie der Landisopoden des Ostbaltikums

Ohne ZusammenfassungAbkürzungen der species-namen im text and in den tabellen A. o. Armadillidium opacum - A. pi. Armadillidium pictum - A. pu. Armadillidium pulchellum - A.z. Armadillidium zenckeri - C. Cylisticus convexus - H. m. Haplophthalmus mengii - L. Ligidium hypnorum - O. Oniseus asellus - P. c. Porcellium conspersum - P. p. Porcellio pictus - P. r. Tracheoniscus rathkei - P. sc. Porcellio scaber - Ph. Philoscia muscorum sylvestris - Tr. Trichoniscus caelebs, elisabethae, elisabethae estoniensis