Effect of Photoperiod on Longevity, Food Consumption, and Reproduction of Holotrichia oblita (Coleoptera: Scarabaeidae).

Holotrichia oblita (Faldermann) (Coleoptera: Scarabaeidae) is a major soil insect pest that damages forest trees, crops, and lawns. Adults of H. oblita fly, forage, and mate at night but remain underground during the day. We studied the effect of photoperiod on H. oblita reproduction. H. oblita females laid more eggs at 8:16 (L:D) h and 0:24 (L:D) h than other photoperiods. As the scotophase increased, the preoviposition period decreased and the oviposition period increased. Female longevity exceeded that of males at all photoperiods, and both males and females at 0:24 (L:D) h had the shortest longevity. The number of eggs laid per female increased with increasing food consumption. Females at 8:16 (L:D) h had the greatest food consumption and laid the most eggs, while females at 24:0 (L:D) h had the lowest food consumption and laid few eggs. The food intake of adults increased gradually and decreased slowly after reaching a peak. Females began to lay eggs when their food consumption reached a maximum. These results indicate that a scotophase is necessary for the reproduction of H. oblita. A long scotophase promotes greater oviposition. The effect of photoperiod on reproduction is affected by food intake.

A comparative study of mechanical strain, icariin and combination stimulations on improving osteoinductive potential via NF-kappaB activation in osteoblast-like cells.

BACKGROUND: The combination of drugs and exercise was the effective treatment in bone injure and rebuilding in clinic. As mechanical strain has potential in inducing the differentiation of osteoblasts in our previous study, the further research to investigate the combination of mechanical strain and icariin stimulation on inducing osteoblast proliferation, differentiation and the possible mechanism in MC3T3-E1 cell line. METHODS: A whole cell enzyme-linked immunosorbent assay that detects the bromodeoxyuridine incorporation during DNA synthesis was applied to evaluate the proliferation. The mRNA expression of alkaline phosphatase (ALP), osteocalcin (OCN), type I collagen (Col I), bone morphogenetic protein-2 (BMP-2) and BMP-4 was detected by real-time reverse-transcription polymerase chain reaction. The activity of ALP was analyzed by ELISA and the protein expression of OCN, Col I and BMP-2 was assessed by western blot. Moreover, the activity of nuclear transcription factor kappa-B (NF-κB) signaling pathway was investigated with the expression of inhibitor of κB (IκB) α, phosphorylation of IκB-α (P-IκB-α), p65, P-p65 by western blot. RESULTS: We observed that compared to single mechanical strain or icariin stimulation, the mRNA and protein expressions of ALP (P < 0.05 or P < 0.01), OCN (P < 0.01) and Col I (P < 0.05 or P < 0.01) were increased significantly by the combination of mechanical strain and icariin stimulation. Moreover, the combination of mechanical strain and icariin stimulation could up-regulate the expression of BMP-2 (P < 0.01) and BMP-4 compared to single mechanical strain or icariin stimulation. The combination of mechanical strain and icariin stimulation could activate NF-κB signaling pathway by increasing the expression of IκB α, P-IκB-α, p65, P-p65 (P < 0.01). CONCLUSION: The combination of mechanical strain and icariin stimulation could activate the NF-κB pathway to improve the proliferation, differentiation of osteoblast-like cells.