O(3)-(2-Acetylamino-2-deoxy-β-d-glucopyranosyl)-oleanolic acid,a novel triterpenoid glycoside from two Pithecellobium species

A new triterpenoid glycoside containing an amino sugar moiety has been isolated from Pithecellobium cubense and P. arboreum and identified as O(3)- (2-acetylamino-2-deoxy-β-d-glucopyranosyl)oleanolic acid. β-d-Glucopyranosyl-α-spinasterol was also obtained from P. cubense.     

Steroidogenesis in isolated adrenocortical cells. Correlation with receptor-bound adenosine 3′:5′-cyclic monophosphate

Because several groups have recently questioned a mediating role for cyclic AMP in adrenocortical steroidogenesis, we analysed the problem in more detail by measuring three different cyclic AMP pools in cells isolated from decapsulated rat adrenals. Extra-cellular, total intracellular and bound intracellular cyclic AMP were determined by radioimmunoassay in comparison with corticosterone production induced by low corticotropin concentrations. The increase in extracellular and total intracellular cyclic AMP with low corticotropin concentrations was dependent on the presence of a phosphodiesterase inhibitor and short incubation times. Bound intracellular cyclic AMP was less dependent on these two parameters. In unstimulated cells cyclic AMP bound to its receptor represents only a small fraction of the total intracellular cyclic AMP. After stimulation by a concentration of corticotropin around the threshold for corticosterone production, an increase in bound cyclic AMP was observed which correlated very well with steroidogenesis both temporally and with respect to corticotropin concentration. This finding was complemented by measuring a concomitant decrease in free receptor sites. Full occupancy of the receptors was not necessary for maximal steroidogenesis. Binding kinetics of cyclic [(3)H]AMP in concentrations equivalent to the intracellular cyclic AMP concentration suggest the presence of at least three different intracellular cyclic AMP pools. These observations are in agreement with a possible role for cyclic AMP as a mediator of acute steroidogenesis induced by low corticotropin concentrations.     

Activation of old cuticle chitin as a substrate for chitinase in the molt of Manduca

During the molt, chitin in the old cuticle of $\text{Manduca}$ is digested by chitinase taken up from molting fluid, but the chitin in intact (= premolt) cuticle is not accessible to chitinase. As a prerequisite of digestion, old cuticle chitin is rendered competent to serve as chitinase substrate in a reaction attributable to trypsin-like proteolytic activity of molting fluid.     

TECHNICAL CONSIDERATIONS IN CANNULATING THE ASCENDING AORTA

A successfully used technique of aortic arch cannulation is reported. This cannula is inexpensive and can be made easily in the hospital. The position and advantages of the cannula are discussed.     

C2 deficiency in man. genetic relationship to a mixed lymphocyte reaction determinant (7a*)

Three unrelated individuals with, respectively, lupus erythematosus, polyarteritis, and membranoproliferative glomerulonephritis and totally deficient in the second component of complement are demonstrated to be mutually poorly reactive in mixed lymphocyte culture and homozygous for the mixed lymphocyte reaction determinant (MLR-S or LD) short 7a (7a^*). The gene controlling the elaboration of C2 in man is shown to be separate from, and probably to map outside of, the second locus ofHL-A and theMLR-S locus. Genetic linkage disequilibrium is strongly suggested between HL-A 10, W18, 7a^*, and C2 deficiency.     

Induction of defense-related enzymes in soybean leaves by class IId bacteriocins (thuricin 17 and bacthuricin F4) purified from Bacillus strains

We have recently discovered a new class of bacteriocin (class IId) which stimulates plant growth in a way similar to Nod factors. Nod factors have been shown to provoke aspects of plant disease resistance. We investigated the effects of bacteriocins [thuricin 17 (T17) and bacthuricin F4 (BF4)] on the activities of phenylalanine ammonia lyase (PAL), guaiacol peroxidase (POD), ascorbate peroxidase (APX), superoxide dismutase (SOD), and polyphenol oxidase (PPO). Bacteriocin solutions were fed into the cut stems of soybean (Glycine max L. Merr. cv. OAC Bayfield) seedlings at the first trifoliate stage. PAL activity in T17 treated leaves was the highest at 72 h after treatment and was 75.5% greater than the control at that time. At 72 h after treatment POD activities in T17 and BF4 treated leaves increased by 72.7 and 91.3%, respectively, as compared with the control treatment. APX activity was 52.3 and 49.6% respectively, greater than the control in T17 and BF4 treated leaves at 72 h after treatment. SOD activity in T17 treated leaves was the highest at 72 h after treatment and was 26.0% greater than the control at that time. SOD activity was 70.5 and 60.2% greater, respectively, than the control in T17 and BF4 treated leaves, at 72 h. Using PAGE we found that one APX isozyme (28 kDa isoform) showed the strongest induction in all bacteriocin treated leaves at 72 h. Activity of the seven SOD isozymes was increased by both bacteriocins, relative to the control treatment. The 33 kDa PPO isozyme was induced strongly by both bacteriocins, relative to the control treatment. These results indicate that class IId bacteriocins can act as an inducer of plant disease defense-related enzymes and may be acting through mechanisms similar to Nod factors.     

Patch Connectivity and Genetic Variation in Two Congeneric Grasshopper Species with Different Habitat Preferences

Two congeneric species of grasshopper, Stenobothrus lineatus and S. stigmaticus, are compared in an analysis of genetic structure relative to their observed mobility, and to the spatial structure of their habitat networks. The species differ in their habitat requirements, the latter being rarer and more restricted to isolated patches. We tested for different patch connectivity between the two species in an analysis of genetic variance (based on allozymes) under the assumption that, besides isolation, rarity influences the genetic parameters. Between the species we found no differences in genetic structure as estimated by F_ST; i.e., no isolation effects and no apparent differences between the species in the potential to move between habitat fragments on either a local or regional scale were found. However, the amount of genetic variation in the more widely distributed and less xerothermic S. lineatus was significantly higher than in S. stigmaticus. Some consistency with observed philopatry within patches was found (F_IS > 0), but we consider regular dispersal events of medium and especially long distance to cause the habitat linking. We conclude that the connectivity between occupied patches inferred by genetic analyses can seldom be derived from low observed life-time movements recorded by conventional marking studies. Consequences of applying observed relative to indirect dispersal estimates for the examination of grasshopper metapopulations are discussed.