The influence of fenbutatin-oxide use on organotin resistance in two-spotted mite Tetranychus urticae koch (Acari: Tetranychidae)

A strain of Tetranychus urticae from pears was evaluated for cyhexatin and fenbutatin-oxide resistance after field control failure to the latter occurred. High-level fenbutatin-oxide resistance was confirmed in the field strain. Fenbutatin-oxide resistance was >1,500 fold (based on flowable powder) and 127 fold (based on emulsifiable concentrate). However, the level of cyhexatin resistance was only 9.8 fold which was similar to levels previously found. This provides a stark warning against the overuse of fenbutatin-oxide.     

Aggregation-deficient embryonal carcinoma cells: defects in peanut agglutinin (PNA) receptors

The components involved in cell adhesion were studied using the H6 line of embryonal carcinoma cells. H6 cells are especially suitable for studies on cell interactions, since genetic mutants can be selected, and various processes of cell adhesion can be controlled by regulating the calcium concentration in the medium. Three aggregation-defective variants of H6 were isolated, all of which showed reduced binding of the lectin, peanut agglutinin (PNA). Quantitation of PNA receptors on the cell surface by immunoprecipitation of iodinated surface proteins indicated that these receptors were reduced on the variants by one-half to one-quarter. The separation of immunoprecipitated PNA receptors on sodium-dodecyl-sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that one type of receptor, with an apparent molecular weight of 94 kilodaltons, was reduced. Parental and variant cells bind similar quantities of concanavalin A and soybean agglutinin, suggesting that there is no generalized effect on major glycoproteins. Thus, the defect in aggregation and the defect in the 94-kilodalton protein may be correlated, and this glycoprotein may have a role in the mediation of H6 cell-cell adhesion.     

The development of seasonal variation in gonadal hormones and body weight in the maturing squirrel monkey

Captive-born squirrel monkeys of three different subtypes (Colombian, Bolivian, Peruvian), ranging in age from 1 to 4.5 years for males and 1 to 3.5 years for females, were examined at 3-month intervals throughout the year for seasonal changes in levels of plasma testosterone and progesterone and in body weight. Cyclical activity of testosterone in males began between 2 and 3 years of age but became more defined by the time the animals were 3–4 years old. Peak values occurred in February and May and corresponded to the the time of year in which adults normally mate. Elevations of progesterone occurred initially at approximately 2.5 years of age in February and May, and mainly infernales of the Colombian subtype. However,unlike levels of testosterone in males of this age, which declined in August and November (following the typical breeding season), levels of progesterone in females continued to increase during these months. Seasonal changes in body weight were also found in males but these changes were less evident than, and did not correlate with, hormonal changes.     

Suppression of human lymphocyte DNA and protein synthesis in vitro by adenosine and eight modified adenine nucleosides in the presence or in the absence of adenosine deaminase inhibitors, 2′-deoxycoformycin (DCF) and erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA)

Adenosine and eight modified adenine nucleosides in the presence or in the absence of adenosine deaminase (ADA) inhibitors, 2′-deoxycoformycin or erythro-9-(2-hydroxy-3-nonyl) adenine, were investigated with regard to their effects on phytohemagglutinin-stimulated human lymphocytes in vitro. Protein and DNA synthesis were inhibited depending upon the specific nucleoside, presence or absence of ADA inhibitor, and time of addition of nucleoside to cultures. A possible role for the modified adenine nucleosides in causing in vivo immunodeficiency is proposed.     

A review on temperature and humidity effects on Drosophila suzukii population dynamics

1. Drosophila suzukii is an invasive polyphagous pest of wild and cultivated soft‐skinned fruits, which can cause widespread economic damage in orchards and vineyards.
2. The simulation and prediction of D. suzukii's population dynamics would be helpful for guiding pest management. Therefore, we reviewed and summarized the current knowledge on effects of air temperature and relative humidity on different life cycle parameters of D. suzukii.
3. The literature summary presented shows that high oviposition rates can occur between 18 and 30 °C. Temperatures between 16 and 25 °C resulted in fast and high egg‐to‐adult development success of more than 80%. Oviposition and adult life span were positively affected by high relative humidity; however, the factor humidity is so far rarely investigated.
4. We assume that this is one reason why relative humidity usually is not considered in modelling approaches, which are summarized herein. The high number of recently published research articles on D. suzukii's life cycle suggests that there is already a lot of knowledge available on its biology. However, there are still considerable research gaps mentioned in the literature, which are also summarized herein.
5. Nevertheless, we conclude that sufficient temperature data in the literature are suitable to understand and predict population dynamics of D. suzukii, in order to assist pest management in the field.