Juvenile hormones: Their role in the regulation of the pheromonal communication system of the armyworm moth,Pseudaletia unipuncta

Recently, much effort has been devoted to the elucidation of the neuro-endocrine mechanisms regulating the biosynthesis and emission of sex pheromones in the Lepidoptera. The available data indicate that the hormonal mechanisms involved vary considerably among species. For example, compelling evidence that juvenile hormones (JH) play a role in the control of sex pheromone production has been presented only for the armyworm moth, Pseudaletia unipuncta. In this species, females that are allatectomized at emergence neither produce nor release pheromone, but both activities are restored following replacement therapy with synthetic JH. However, injection of synthetic JH into neck-ligated females does not induce pheromone biosynthesis, whereas treatment with either a brain homogenate or synthetic PBAN results in a rise in the pheromone titer. These results indicate that the role played by JH is an indirect one and that the tropic factor is a PBAN-like substance. Studies on in vitro JH biosynthesis by isolated corpora allata of P. unipuncta have shown that the low JH output observed early in the life of adult females coincides with the absence of both calling behavior and pheromone production. The subsequent increase in the rates of JH biosynthesis correlates with the onset of pheromone production and release. We have therefore proposed that JH titers must pass a threshold level before the circadian release of PBAN and calling behavior can begin. Furthermore, recent experiments suggest that the continuous presence of JH is necessary for calling behavior to be maintained once initiated. Lastly, we present data suggesting a role for JH or JH acids in the receptivity of P. unipuncta males to the female sex pheromone. © 1994 Wiley-Liss, Inc.     

Structural definition of the non-reducing termini of mannose-capped LAM from Mycobacterium tuberculosis through selective enzymatic degradation and fast atom bombardment-mass spectrometry

The application of extracellular arabinases from aCellulomonassp. and fast atom bombardment-mass spectrometry (FAB-MS) providednew insight into the structure of lipoarabinomannan (LAM) ofMycobacterium tuberculosis, a key molecule in the pathogenesisand physiology of the tubercle bacillus. Previously, the non-reducingarabinan ends of LAM from the virulent (Erdman) strain of M.tuberculosiswere shown to be ‘capped’ by short (a1     

Estimation of prediction error variances via Monte Carlo sampling methods using different formulations of the prediction error variance

Calculation of the exact prediction error variance covariance matrix is often computationally too demanding, which limits its application in REML algorithms, the calculation of accuracies of estimated breeding values and the control of variance of response to selection. Alternatively Monte Carlo sampling can be used to calculate approximations of the prediction error variance, which converge to the true values if enough samples are used. However, in practical situations the number of samples, which are computationally feasible, is limited. The objective of this study was to compare the convergence rate of different formulations of the prediction error variance calculated using Monte Carlo sampling. Four of these formulations were published, four were corresponding alternative versions, and two were derived as part of this study. The different formulations had different convergence rates and these were shown to depend on the number of samples and on the level of prediction error variance. Four formulations were competitive and these made use of information on either the variance of the estimated breeding value and on the variance of the true breeding value minus the estimated breeding value or on the covariance between the true and estimated breeding values.     

ACCIDENTAL INJURIES TO WOMEN—Obstetrical and Gynecological Problems Associated with Damage Claims

Women who have been injured should be examined for possible gynecological injury within 24 hours of the accident.Injuries to pregnant women do not usually cause an obstetrical crisis. When such an event does occur, there is positive evidence which relates it to the accident if there was such relationship.Metrorrhagia and menorrhagia are common sequelae of physical and psychological injury, but they are of temporary nature in cases in which there is no demonstrable pathologic change upon pelvic examination.Uterine prolapse, cystocele and rectocele are not caused by a single injury except in extremely rare instances. When vaginal vault injury has occurred as a result of a single injury, there is plentiful evidence of severe tissue damage.     

Scleroglucan and oxalic acid formation by Sclerotium glucanicum in sucrose supplemented fermentations

Summary Strategies for adding sucrose to stationary phase cultures of Sclerotium glucanicum to improve scleroglucan production were examined. Particular attention was paid to the effect of sucrose supplementation on the formation of the toxic by-product, oxalic acid. The rate of addition of sucrose was found to markedly influence the outcome of the process, with addition at a rate of 0.084 gl^–1h^–1 giving a 50% improvement in broth biopolymer concentration. Additions at higher rates seemed to cause inhibition of the culture. However, greatly increased oxalic acid concentrations in the sucrose supplemented fermentations, and the impact of unfavourable changes in productivity and specific productivity call into question the utility of this proposed method of process improvement for this microorganism.     

Physical and physiological factors in diapause initiation of two hyperparasites of the tobacco hornworm,Manduca sexta

Hypopteromalus tabacum diapauses as a last larval instar and Catolaccus aeneoviridis as a non-pharate pupa within cocoons of the primary parasite, Apanteles congregatus. Four factors (photoperiod, temperature, maternal age, and physiological state of the host) were tested for their significance in diapause initiation of both species. A 10L : 14D photoperiod produced a higher incidence of diapausing individuals than a 13L : 11D photoperiod. In the temperature range from 18 to 24°C, the incidence of diapause was inversely related to temperature. The incidence of progeny entering diapause varied with the age of the mother, younger ones producing fewer diapausing offspring. An increase in the number of C. aeneoviridis entering diapause was observed when the host, A. congregatus, was in the diapausing, rather than the nondiapausing condition. Analysis of the data indicated that interactions between these four factors also played an important rôle in diapause initiation of both species.