A mutant of the antibiotic resistance factor R124 with altered copy number

Summary A mutation conferring increased antibiotic resistance onSalmonella typhimurium strain 11G carrying R124 was plasmid determined; strains harbouring the mutant plasmid contained more DNA as ccc plasmid than those harbouring R124. The increased copy number was manifested at all growth rates at all growth rates tested.This work was supported by a grant (to R. J. R.) from the Central Research Fund of the University of London and by a studentship (to J. J. P.) from the Science Research Council.     

Influence of PGA1 on cartilage growth

Summary Using the Fell technique of organ culture of cartilage in a chemically defined medium, it has been shown that prostaglandin A₁ at a concentration of 25 g/ml caused chondrocyte death in chick embryonic limb rudiments. An equimolar concentration of PGE₂ was not toxic to the cells.Acknowledgments. We are grateful for the support of C. J. K. by the Medical Research Council and of D. L. G. by the Arthritis and Rheumatism Council for Research. Our thanks are due to Dame Honor Fell, F. R. S. for invaluable advice and guidance, to Dr J. Pike (Upjohn Co.) for supplies of prostaglandin A₁, and to Dr Sylvia Fitton-Jackson for the gift of culture medium.     

Studies of the blood ofAscidia ceratodes. Total blood cell counts,differential blood cell counts,hematocrit values,seasonal variations,and fluorescent characteristics of blood cells

Summary Seasonal, and animal size and weight variations of the blood cells of the vanadium-containing ascidian,Ascidia ceratodes, were determined. The fluorescent properties of various cell types were ascertained, and discussed in terms of cell development, phylogenic position of the species, and chemicals in the cells.This investigation was supported by a grant from the Research Corporation and one of us (W.R.B.) received partial support from various University of California administrated fellowships. The current address of W.R.B. is Chevron Research Products, Richmond, CA. The use of the facilities at the Bodega Marine Laboratory, University of California are acknowledged.     

On the mechanism of immunosympathectomy

Summary The effects in vivo and in vitro of the antiserum to mouse nerve growth factor (NGF) are independent of the presence of complement. These results are consistent with the view that the antiserum acts by neutralizing endogenous NGF.Acknowledgments. Financial support from the Whitehall Foundation, New York, The Wellcome Foundation, U.K. (to J.R.C.) and the Science Research Council (Studentship to M.E.) is gratefully acknowledged. We thank Professor J.H. Humphrey, National Institute for Medical, Research, Mill Hill, London, for discussion and determination of plasma C3 levels.     

The defensive function of cyanogenesis in natural populations

Summary Detailed ecological studies of some maritime populations of Lotus corniculatus L. have shown that the distribution of the cyanogenic form of this plant is directly related to the distribution and density of molluscs which graze selectively the acyanogenic form. This work, on a genetic polymorphism, is interpreted as giving direct evidence of chemical defence in natural populations.Acknowledgment. We are most grateful to the Science Research Council (B/RG/3539, W.M.E. and D.A.J.) and to the Natural Environment Research Council and the Sir Philip Reckitt Educational Trust (research studentship, R.J.K.) for the financial support of this work.     

Predominant expression of σ and ε globin genes in human leukemia K-562(S6) variant cell line

Summary In the human leukemia K-562(S6) cell line (a) the accumulation ofa-globin chains is low or absent, (b) -globin gene expression is correlated with expression of -chains and (c) the genes responsible for the terminal cell division are not operated within 8–12 cell cycles, while K-562 (S6) cells are fully induced to erythroid differentiation.This work was supported by grants from the Italian National Research Council (C.N.R.) G. R. is a recipient of a fellowship from the National Committee for Nuclear Energy, Rome. Address for reprint requests: R. G., Centro di Studi Biochimici, Via L. Borsari 46, I-44100 Ferrara.     

Effects of tranylcypromine on the concentrations of some trace amines in the diencephalon and hippocampus of the rat

Summary Concentrations of 4 trace amines in diencephalon and hippocampus of the rat were measured by integrated-ioncurrent mass spectrometry after administration of the antidepressant drug, tranylcypromine. Much larger increases were observed for 2-phenylethylamine and tryptamine than for m- and p-tyramine.Financial support has been provided by the Medical Research Council of Canada, the Psychiatric Services Branch, Province of Saskatchewan, the Alberta Mental health Research Fund, and the Special Services and Research Committee, University of Alberta Hospital.Acknowledgments. The authors wish to thank Dr B.A. Davis for synthesizing the deuterated internal standards and Dr D.A. Durden for supervising the mass spectral analyses. Expert technical assistance was provided by Mr R.C. Mag-Atas and Ms D.G. Calverley. The advice and encouragement of Professors W. G. Dewhurst and A. A. Boulton are gratefully acknowledged.     

Cattle grazing behavior regulates tick populations

Summary Analysis of field population data showed that host-seeking larvae of the tickBoophilus microplus were less successful in attaching to their hosts when larval densities were high. Experimental results showed that cattle hosts detected and avoided high densities of larvae in pasture. The finding reveals a previously unknown population-regulating mechanism for ticks, which are important pests of livestock.Acknowledgment. The authors wish to thank G. Maywald, D. Stegeman, R. Tozer, A. Voll, G. Milne and J. Osborne who helped with the observations. The Australian Meat Research Committee (AMRC) and the Australian Centre for International Agricultural Research (ACIAR) provided some financial support for the project and A. Edwards assisted greatly with the photography.     

The effect of leafhopper infestation on the respiration of castor bean varieties in relation to their resistance toEmpoasca flavescens (F.) (Homoptera: Jassidae)

Zusammenfassung Die Saugtätigkeit der JassideEmpoasca flavescens (F.) führte zu einer um 44% gesteigerten Respiration von geschädigten, anfälligen Rizinuspflanzen (Ricinus communis L.) im Vergleich zu 11.6% und 3.7% bei Pflanzen einer toleranten und resistenten Sorte. Diese Zunahme war bei der anfälligen Sorte verknüpft mit einer gesteigerten Anhäufung von Rohrzucker, Gesamtstickstoff und Gesamtaminosäuregehalt.

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This study formed part of the Doctoral Thesis submitted to the University of Madras and financial support was given by the Council of Scientific and Industrial Research, Government of India, New Delhi. Grateful appreciation is extended to Prof. A. R.Seshadri, Agricultural College and Research Institute, Coimbatore, India and Prof. R. H.Painter, Kansas State University, Kansas, U.S.A. for their valuable suggestions made during the course of the study.     

A field-portable racetrack and timer for measuring acceleration and speed of small cursorial animals

Summary We describe a relatively inexpensive, field-portable racetrack and timer that can be used to measure acceleration and maximum speed of small cursorial animals. Procedures for interfacing the racetrack to microprocessors are also outlined.This research was supported by NSF DEB 78-12124, the Miller Institute for Basic Research in Science (University of California, Berkeley), and by the Graduate School Research Fund (University of Washington, Seattle). The authors gladly acknowledge the advice of R. Reinstatler, J.R. Simpson, M.O. Smith, and especially A. M. Hawkins.     

Gastric mucus effusion elicited by oral copper compounds: Potential anti-ulcer activity

Summary In rats, both Cu(I) and Cu(II) show an irritancy profile not shared with Cu^o or Zn(II) or Ni(II). The gastric response to Cu(II), i.e. copius fluid and mucus secretion, can protect the stomach from the acute ulcerative effects of aspirin or physical stress administered subsequently.to whom all enquiries should be addressed, Supported by grants from the National Health and Medical Research Council (Austr.) and University of Tasmania Research Commitee.Acknowledgments: ProfessorsW. R. Walker (Newcastle, Austr.) andL. Field (Nashville, Tenn.) for gifts of Cu(I) and Zn complexes;Dr. J. R. J. Sorenson (Cincinnatti, Ohio) for illuminating discussion; Drs.D. D. Perrin (Canberra) andR. P. Agarwal (Washington D. C.) for providing stability constants and much helpful advice.     

Effect of pancreatic polypeptide on DNA-synthesis in the pancreas

Summary Bovine pancreatic polypeptide increases DNA-synthesis in the rat pancreas; no effect is observed in stomach (oxyntic area), duodenum or liver. BPP neither augments or inhibits the trophic action of cholecystokinin.Acknowledgment. Pure pancreatic polypeptide was donated by Dr. R. E. Chance (Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Ind, USA). G. R. Greenberg is supported by a Fellowship of the Medical Research Council of Canada.     

Pituitary growth hormone and hypothalamic somatostatin in young female rats versus old constant estrous female rats

Summary Pituitary content and concentration of growth hormone was significantly reduced, and hypothalamic somatostatin content significantly increased, in old constant estrous as compared to young female rats. Increased levels of somatostatin may contribute to the decrease in pituitary growth hormone levels in these animals.This work was supported by NIH Research grants AG-00416 (J.M.) from the National Institute on Aging, AM-04784 (J.M.) from the NIAMDD, and NIA postdoctoral fellowships AG-05208 (L.J.F.) and AG-05147 (W.E.S.).     

Tyrosinase-cytalyzed conjugation of dopa with glutathione

Summary A convenient method is described for the preparation of 5-S- and 2-S-glutathionyldopa, based on tyrosinase oxidation of dopa in the presence of glutathione. The yields of 5-S, 2-S, and 6-S isomers produced were about 76, 12, and 5%, respectively.One of the authors (G.P.) thanks the C.N.R. (P.F. Chimica Fine e Secondaria) for partial financial support.     

Depletion of synaptic vesicles at the frog (Rana pipiens) neuromuscular junctions by tetraphenylboron

Summary At the frog neuromuscular junction tetraphenylboron produced a decrease in miniature endplate potential amplitude, accompanied by a decrease in the number but not the size of synaptic vesicles.This work was supported by NIH Grants Nos NS-07740 and NS-05707 to R. L. P. and was done during the tenure of a Research Fellowship of Muscular Dystrophy Associations of America, a Wellcome Research Travel Grant and a grant from the Carnegie Trust for the Universities of Scotland to I. G. M. The assistance of Dr.R. M. Schnitzler, W. G. Boldosser andP. M. Spannbauer is gratefully acknowledged.     

Effects of acute intoxication with uranyl nitrate on bone formation

Summary The alteration of bone formation by an acute intoxication with uranyl nitrate is demonstrated by histologic and histometric methods. When compared with the controls, intoxicated animals showed a markedly lower density in healing sockets, while bone formation was reduced in healing sockets as well as in metaphyseal bone.Acknowledgments. This work was supported in part by grant No. 8461 d/82 of the National Research Council Argentina and by Research Contract No. 2816/R1/R2 of the International Atomic Energy Agency. The authors wish to acknowledge the valuble technical assistance of Miss Ofelia Chiesa and Miss Patricia Mandalunis.     

Role of salivary glands in the maintenance of midgut amylase activity inPeriplaneta americana L.

Summary It was experimentally demonstrated, by the surgical removal of salivary glands and severence of salivary ducts, that most of the amylase in the gut ofPeriplaneta americana comes from the salivary glands.We wish to acknowledge Prof. H. Swarup (Jiwaji University, Gwalior, M.P.) for working facilities provided at School of Studies in Zoology, Vikram University, Ujjain, M.P., and Council of Scientific and Industrial Research, New Delhi, for fincancial support in the form of Junior Research Fellowship to one of us (O.P.A.)     

Australian goats detoxify the goitrogen 3-hydroxy-4(1H) pyridone (DHP) after rumen infusion from an indonesian goat

Summary The failure of Australian goats fedLeucaena leucocephala (leucaena) to degrade 3-hydroxy-4(1H) pyridone (DHP), the goitrogenic metabolite of mimosine, was overcome when they were infused with rumen fluid from an Indonesían goat. The leucaena toxicity problem in Australia may well be solved by transfer of specific bacteria capable of degrading DHP anaerobically.We acknowkledge the assistance of R.G. Megarrity in preparation of the goats in Australia and R. Dixon and staff at the CSIRO Lansdown Research Station for preparation of the feed. In Balai Penelitian Ternak; G. Riding, and Suwandi for the metabolism study facilities, Riad the feeding, Miss Leanne Rochanda sample preparation and Mrs M. Young for veterinary assistance. Analyses were carried out by R. Lowe, Jernih Rosida and Wildan.     

The pineal gland is very large and active in newborn antarctic seals

Summary The pineal gland of newborn elephant seals and Weddell seals is larger than in adult females. The gland is considerably larger at birth in Weddell seals than in elephant seals. The former experience greater extremes of temperature. Plasma melatonin concentrations in excess of 2000 pg/ml were recorded in the first days of life, compared with 20–50 pg/ml in adults.Acknowledgment. We thank members of the Australian National Antarctic Research Expedition to Macquarie Island for assistance with collection of elephant seal samples, in particular G. Burns, D. Carroll, G. Copson, R. Ledingham and S. Pye. The support of the National Science Foundation, USA, and personnel at the United States Antarctic Research Program base at McMurdo Sound, Antarctica, are gratefully acknowledged. The Tasmanian National Parks and Wildlife Service kindly issued permits to collect specimens at Macquarie Island.     

Isolation and structural elucidation of 3,6-dioxo-hexahydro-pyrrolo [1,2-a]-pyrazine from the echinodermLuidia clathrata

Zusammenfassung Es wird über die Isolierung und Charakterisierung der Titelverbindung (Gly-l-Pro Lactam, I) aus dem SeesternLuidia clathrata berichtet. Die Kristallstruktur dieses Dioxopiperazinderivats wurde ermittelt. Der Piperazinring liegt in der Wannen-Konformation vor.

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This investigation was supported by contract No. NIH-71-2308 from Chemotherapy, National Cancer Institute, National Institutes of Health and by Public Health Service Research Grant No. CA-11451-03 from the National Cancer Institute. The authors also gratefully acknowledge support from the National Science Foundation which provided the X-ray diffractometer and mass spectrometer. For the previous contribution of this series seeG. R. Pettit, R. H. Ode andT. B. Harvey, III, Lloydia,36 (1973).