Morphology of the Male Reproductive System and Spermiogenesis of Dendroctonus armandi Tsai and Li (Coleoptera: Curculionidae: Scolytinae).

Studying the reproductive attributes of pests is central to understanding their life cycle history and in crafting management strategies to regulate, if not bring down, their population below threshold levels. In this article, the morphology of the male reproductive tract, topology of the spermatozoa, and salient features of spermiogenesis in the Chinese white pine beetle, Dendroctonus armandi Tsai and Li was studied to provide baseline information for further pest management studies. Results showed that male reproductive tract of this species differs from those documented in other Coleopterans by having 20 testicular tubules in each testis and the presence of two types of accessory glands. The spermatozoon is seen having peculiar characteristics such as an "h"-shaped acrosomal vesicle with a "puff"-like expansion, one centriole, one large spongy body, and two accessory bodies. Despite with some morphological differences of the male reproductive organ, spermatogenesis in this organism is similar to other Coleopterans. Overall, detailed studies regarding the components of the primary male reproductive organ of this beetle species would expand the knowledge on the less-understood biology of Coleopteran pests and would help in designing regulatory measures to conserve endemic and indigenous pine trees in China.

Revealing binding interaction between seven drugs and immobilized ß2-adrenoceptor by high-performance affinity chromatography using frontal analysis.

The development of new approaches to study the affinity between ligands and G-protein-coupled receptors proves to be of growing interest for pharmacologists, chemists, and biologists. The aim of this work was to determine the binding of seven drugs to ß2-adrenoceptors by frontal analysis using immobilized receptor stationary phase. The dissociation constants (Kd ) were determined to be (3.16 ± 0.09) × 10(-4) M for salbutamol, (4.29 ± 0.12) × 10(-4) M for terbutaline, (6.19 ± 0.16) × 10(-4) M for methoxyphenamine, (2.11 ± 0.07) × 10(-4) M for tulobuterol, (1.82 ± 0.11) × 10(-4) M for fenoterol, (9.75 ± 0.24) × 10(-6) M formoterol, and (9.84 ± 0.26) × 10(-5) M for clenbuterol. These results showed a good correlation with the data determined by radioligand binding assay. Further investigations revealed that the dissociation constant mainly attributed to the number of hydrogen bonds in the structures of ligands. This study indicates that affinity chromatography using immobilized receptor stationary phase can be used for the direct determination of drug-receptor binding interactions and has the potential to become a reliable alternative for quantitative studies of ligand-receptor interactions.