Role of low ecdysteroid levels in the early last larval instar ofBombyx mori

The relationship between juvenile hormone and ecdysteroid titers during the early stage of the last larval instar of the silkworm,Bombyx mori, was examined in this study. When larvae were fed 20-hydroxyecdysone-supplemented mulberry leaves throughout the last larval instar, 100% underwent supernumerary larval molting instead of metamorphosis. The application of juvenile hormone mimic during the early last instar did not induce supernumerary larval molting, but did delay metamorphosis. Temporal and quantitative ecdysteroid titer measurements revealed that in normal larvae the titers maintained very low levels (3–12 ng/ml) during the early stage of the last instar; however, in 20-hydroxyecdysone-treated larvae, levels ranging from 24 to 45 ng/ml were detected, and a major peak (246 ng/ml) was observed on day 6. These results show that very low ecdysteroid titer levels during the early stage of the last larval instar may play an important role in initiating decreases in juvenile hormone titers as well as in directing metamorphosis.     

Titers of ecdysone, 20-hydroxyecdysone and juvenile hormone III throughout the life cycle of a hemimetabolous insect,the ovoviviparous cockroachNauphoeta cinerea

Summary Titers of ecdysone, 20-hydroxyecdysone and juvenile hormone III were measured in whole body extracts or hemolymph of embryos, first, penultimate and last stadium nymphs, and adult females ofNaupoheta cinerea. We used a gas-chromatography/mass spectrometry method for quantifying juvenile hormone and a radio-immunoassay for ecdysteroid determination. Juvenile hormone III is particularly abundant in the embryonic stage (up to 960 ng/g), at a low level in first and penultimate stadium nymphs (2–10 ng/ml) and almost absent in the last nymphal stadium; in the adult female the juvenile hormone titer rises to 180 ng/ml in hemolymph during rapid oocyte growth. The titers of ecdysone and 20-hydroxyecdysone undergo similar fluctuations in the embryonic and nymphal stages, being highest at the time of cuticle formation in the embryo and a few days before the nymphal and adult molts (around 100–200 ng/ml for exdysone and 2–4 g/ml for 20-hydroxyecdysone).Acknowledgments. We thank Mrs A. Tschan for rearing the cockroaches, Mr M. Kaltenrieder for drawing the graphs, Mr G.C. Jamieson and Mrs C. Reuter for GC/MS analyses. We are also grateful to the Swiss National Science Foundation (grant no. 3.291-0.82 to B. Lanzrein) and the United States National Science Foundation (grant no. PCM 82-08665 to D.A. Schooley) for their financial support.     

The effect of anesthetics on the basal secretion of immunoreactive growth hormone in rats]

The authors investigated basal levels of plasma immunoreactive growth-hormone in the rat (R-GH) after administration of 3 different anesthetic drugs: urethan, chloral hydrate and gamma-hdroxy-butyrate (GHB). Lowest R-GH concentrations (5 +/- 3 ng/ml) are observed after urethan; they are significantly higher (15 +/- 4 ng/ml) after chloral hydrate but this anesthetic also causes hyperglycemia (210 +/- 30 mg/100 ml). Normal blood glucose levels are observed under GHB narco-analgesia which elicits a clear-cut R-GH secretory episode (70 +/- 5 ng/ml); basal values (12 +/- 3 ng/ml) are maintained for several hours thereafter.     

On the occurrence of homovanillic acid and 3-methoxy-4-hydroxymandelic acid in human cerebrospinal fluid

Zusammenfassung Es wird papierchromatographisch gezeigt, dass Cerebrospinalflüssigkeit gesunder Menschen sowohl Homovanillinsäure als auch 3-Methoxy-4-hydroxymandelsäure enthält. Die Konzentration der ersteren ist etwa 75 ng/ml und die der letzteren etwa 25 ng/ml.

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Acknowledgment. This work has been supported by grants from Leo Ltd., Hälsingborg, and from the Medical Faculty, University of Göteborg (Sweden). For technical assistance we are indebted to Mrs.I. Olofson.     

Sandwich enzyme immunoassay of mouse mammary tumor virus

Summary A highly sensitive sandwich enzyme immunoassay for the mouse mammary tumor virus (MMTV) is described. The assay can detect 3 ng/ml of MMTV. The enzyme used is ß-D-galactosidase fromEscherichia coli and the solid phase used is a piece of silicon rubber.     

Differential inhibitory effects of noradrenaline upon insulin secretion by the isolated perfused pancreas of the rat

Summary Responses of basal and glucose-induced secretion phases of the isolated perfused pancreas of the rat to graded doses of noradrenaline (NA) are described. Maximal inhibition of basal secretion was achieved at [NA]=40, ng/100 ml; at [NA]=80 ng/100 ml, the 1st phase of glucose induced secretion was abolished; at [NA]=100 ng/100 ml the 2nd phase was abolished. At [NA]40 ng/100 ml basal secretion was less sensitive to NA inhibition than glucose induced output.Acknowledgment. The authors are most grateful to Mr J. Stevenson for advice upon and assistance with statistical analysis of data.     

The Dead Sea — alive again

In the thirteen years of quantitative studies on the microbiology of the Dead Sea from 1980 onwards three distinct periods can be discerned. Mass development of the green unicellular algaDunaliella parva (up to 8,800 cells/ml) and red archaeobacteria (2×10⁷ cells/ml) was observed in 1980, following a dilution of the upper water layers by rain floods. This bloom disappeared at the end of 1982 as a result of a complete mixing of the water column. During the period 1983–1991 the lake was holomictic, and noDunaliella cells were observed. Viable bacteria were present during this period in very low numbers. Heavy rain floods during the winter of 1991–1992 caused a new stratification as the upper five meters of the water column became diluted to 70% of their normal salinity. In this upper water layerDunaliella reappeared (up to 3×10⁴ cells/ml at the beginning of May, rapidly declining to less than 40 cells/ml at the end of July), and a bloom of red archaeobacteria (3×10⁷ cells/ml) once more imparted a red coloration to the lake.     

Aplysianin-A,an antibacterial and antineoplastic glycoprotein in the albumen gland of a sea hare,Aplysia kurodai

Summary Aplysianin-A, an antibacterial and antineoplastic factor in the albumen gland of the sea hareAplysia kurodai, was isolated. It had a molecular weight of approximately 320 kD and consisted of subunits with a molecular weight of 85 kD. It contained 9.8% neutral sugar. Aplysianin A showed 50% inhibition ofBacillus subtilis growth at a concentration of 4 g protein/ml and 50% lysis of murine MM46 tumor cells at 14 ng protein/ml. A partial identity of antigenic specificity of the purified specimen with an antineoplastic factor fromAplysia eggs was observed in immunodiffusion tests.Acknowledgment. We are indebted to the staff of Fisheries Research Laboratory, Faculty of Agriculture, University of Tokyo, Maisaka, for the collection of sea hares.     

The alteration of juvenile hormone titre inSpodoptera litura (F.) due to a baculovirus infection

Summary The haemolymph juvenile hormone levels ofSpodoptera litura were remarkably low (540 Galleria units (GU)/ml) at the last larval moult as well as prior to pupation (194 GU/ml). During the last intermoult period this was 2600 GU/ml for a 24 h-period. On the other hand, the JH level in the haemolymph of NPV-infected last instar larvae was initially 1740 GU/ml but was maintained at 2400–2600 GU/ml during the next 48 h. Finally, the JH titre fell to 1393 GU/ml, but only prior to death. The failure of the diseased larvae to undergo the larval pupal moult is ascribed to the alteration of the JH titre in the haemolymph.     

Juvenile hormone titre and regulation in the cockroachDiploptera punctata

Summary Titres of juvenile hormone (JH) have been determined in both hemolymph and whole body extracts of femaleDiploptera punctata during the first gonotrophic cycle using a method employing gas chromatography/mass spectrometry for qualitative and quantitative analysis. JH III is the sole JH found in both adult and last instarD. punctata. Maximum values of 1500 ng/ml (6M) were observed at the middle of the gonotrophic cycle, when basal oocyte growth rate was greatest. Changes in rates of JH release in vitro by corpora allata paralleled closely the changes in JH titre, suggesting that biosynthesis is a major regulator of titre. JH levels per animal were calculated from observed JH titres, and at certain time points in the gonotrophic cycle JH levels obtained from analysis of whole bodies were significantly greater than those predicted from hemolymph titres. These results suggest the existence of a nonhemolymph JH pool inD. punctata. Decay in JH titre after allatectomy of 5 day females has also been studied. Following a rapid initial decline, the rate of decay slowed appreciably 4 h post-operation. Thus, use of a first-order rate constant to estimate half-life of JH significantly underestimated the longevity of the hormone. The apparent persistence of JH following allatectomy may be due to the existence of a nonhemolymph JH pool.     

Plasma estrogens in Pleurodeles waltlii. Comparison between diploid and triploid females]

Estrogens have been examined in the plasma of diploid and triploid newts Pleurodeles waltlii. Estradiol-17 beta (E2) and estrone (E1) were determined by radioimmunoassay, before and after enzymatic hydrolysis of the conjugates. Total (t) and unconjugated (u) E2 levels were positively correlated (E2u = 0.478 35 E2t + 0.579 98; r = 0.883), but no correlation was detected between E1 levels. No statistical difference was found for the estrogen levels between the different experimental lots of diploid newts (E2t = 7.5 +/- 0.37 ng/ml, E2u = 4.3 +/- 0.20 ng/ml, E1t = 2.19 +/- 0.08 ng/ml, E1t = 0.41 +/- 0.02 ng/ml) but every estrogen level was lower in the triploid group (E2t = 1.8 +/- 0.60, E2u = 1.0 +/- 0.18, E1t = 1.4 +/- 0.13, E1u = 0.3 +/- 0.04 ng/ml). This difference is discussed in relation to lower fertility of the triploid females.     

Effects of diflubenzuron and tunicamycin on N-acetylglucosaminyl transferases in prepupae of the stable fly (Stomoxys calcitrans)

Summary Tunicamycin, an antibiotic, and diflubenzuron, an insect growth regulator, were tested to determine their effects on N-acetylglucosaminyl transferase fromS. calcitrans prepupae. Diflubenzuron had no effect, but tunicamycin inhibited the transfer of GlcNAc-1-P from UDP-GlcNAc to dolicholmonophosphate with an I₅₀ of 1.5–4 ng/ml.     

Occurrence of ecdysone in the blood of the chelicerate arthropod,Limulus polyphemus

Summary A molt promoting substance, assumed to be ecdysone, was discovered inLimulus haemolymph. Preliminary bioassay suggests a titre of 9 ng ecdysone per ml of haemolymph.Supported by the University of Minnesota Graduate School, NSF Grant No. GB 16607 and USPHS Grant No. HO 07336.     

Isolation and characterization of a new hemagglutinin from the red algaGracilaria bursa-pastoris

Summary A new agglutinin has been isolated from the red algaGracilaria bursa-pastoris by affinity chromatography on a yeast mannan-Cellulofine column. This agglutinin was isolated as a monomeric glycoprotein with a relatively low molecular weight. It had an isoelectric point of 4.7 and contained large amounts of Gly, Asx and Glx. It agglutinated trypsin-treated rabbit erythrocytes at the low concentration of 30 ng/ml. The activity was inhibited only by glycoproteins bearing N-glycans. This agglutinin also showed mitogenic activity for mouse splenic lymphocytes.     

Interactions ofΔ 11-tetrahydrocannabinol with cannabinol and cannabidiol following oral administration in man. Assay of cannabinol and cannabidiol by mass fragmentographywith cannabinol and cannabidiol following oral administration in man. Assay of cannabinol and cannabidiol by mass fragmentography

Summary Oral administration to man of 20 mg ¹1-tetrahydrocannabinol (THC) together with placebo or 40 mg cannabinol (CBN) or 40 mg cannabidiol (CBD) gave evidence of a possible limited interaction of THC with CBN but not with CBD as indicated by average plasma THC levels. Peak CBD and CBN concentrations were similar to that of THC, viz. about 5–8 ng/ml.Supported by the Swedish Medical Research Council and grant MH-00424 from the Veterans Administration.     

Relationship between the absolute configuration and the biological activity of juvenile hormone III

Summary The activity of the pure 10R (=natural) and 10S enantiomers of juvenile hormone III (JH III) was determined in 3 different bioassays, and the relative binding affinity of the 2 enantiomers to the haemolymph JH-binding protein of the cockroachNauphoeta cinerea was measured. In theGalleria wax test, a local morphogenetic assay, the 10R enantiomer was 5240 times more active than, the 10S enantiomer, 1Galleria unit corresponding to 0.42 pg of 10R-JH III as compared to 2.2 ng for 10S-JH III. In a systemic morphogenetic assay with the cockroachNauphoeta cinerea 380 times less 10R enantiomer was necessary in order to induce detectable juvenilisation (58 ng 10R and 22 g 10S) and in a systemic gonadotropic assay withNauphoeta cinerea 255 times less 10R was needed to induce vitellogenin synthesis in 50% of the insects (6.7 ng 10R and 1710 ng 10S). In the JH-binding protein assay 10R-JH III had an affinity for the JH-binding protein (lipophorin) which was approximately 46 times higher than that of 10S-JH III.     

Capillary blood flow in the testes and testosterone secretion in the starved rat

Summary The average capillary blood flow in the testes was found to be 181 l/min/g testis tissue (n=19) in rats starved for 5 days and 273 l/min/g (n=18, p<0.01) in the control group. Plasma testosterone was significantly decreased in the starved animals (1.00±0.06 ng/ml vs 5.43±0.63 ng/ml). When starved and control rats were stimulated with human chorion gonadotropin, testosterone values in plasma were greatly increased in both groups. The capillary blood flow was not altered. The data indicate that human chorion gonadotropin can stimulate testosterone production in the starved rat without influencing the reduced capillary blood flow.     

Blood histamine and response of spleen cells to phytohemagglutinins during moderate magnesium deficiency in the rat]

Blood histamine and spleen cell stimulation index by PHA were determined in either magnesium deficient or control Rats. Between the 10th and 17th days of diet (hyperemia and dermatosis period), histaminemia was significantly higher in deficient animals (485 ng/ml) than in control ones (112 ng/ml), but at the 32nd day it came back to normal values. The mean spleen cell stimulation index by PHA was depressed in deficient animals mainly between the 10th and 17th day of the deficiency; 33% of control mean value. A negative correlation is found between histamine level and stimulation index.     

Development of plasma cortisol in calves from birth to 14 days of age]

Plasma cortisol was recorded in 15 calves from birth to 14 days of age by a radio-immunoassay technique. At birth mean cortisol value is 67.3 ng/ml; 6 hrs. later it decreases by 58.4% then it gradually diminishes and about 14 days after, it reaches adult levels (5.1 ng/ml).     

Influence of cysteine on the light production rate of the crustacean cypridina luciferin-luciferase system

Zusammenfassung Cysteinlösung (Cystein-HCl gelöst in 0,1M Phosphatpuffer) von verschiedenen Konzentrationen (0–4,65M) wurde zu Luziferinlösung (gereinigtes kristallines Luziferin gelöst in Methanol, 0,1 mg/ml) oder zu praktisch reiner, gepufferter Luziferaselösung (0,1 mg/ml) zugegeben. Mit zunehmenden Cystein-Konzentrationen ergibt sich eine Zunahme in der Höhe der Reaktionskurve.