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Different environments may drive the evolution of morphological traits due to selection on organismal performance. In lizards, bite force plays an important role both for inter‐ and intra‐specific interactions, such as prey preference, resource competition, predatory defense, and courtship behavior. Individuals with large bite force may benefit from a high reproductive success through territorial defense or predatory deterrence. Under extremely high predation risk from the oophagic kukri snake (Oligodon formosanus), long‐tailed skinks (Eutropis longicaudata) on Orchid Island exhibit an exclusive post‐ovipositional parental care, not found in any other populations. In this study, we tested the assumption that Orchid Island skinks exhibit higher bite force than two other populations without egg‐guarding behavior. We investigated the three hypotheses that best explain this adaptation: (1) Orchid Island skinks have different parental care than Green Island and Taiwan skinks, which may drive larger bite force; (2) in the three populations, male–male competition and mating bites enhance bite force, leading males to present higher bite force than females; (3) head traits are indicators of bite force. Our results show for the first time that Orchid Island skinks exhibit larger bite force than the other populations do, which may be shaped by a higher egg‐predation pressure and the consequent parental behavior. Males exhibit stronger bite force likely due to a stronger sexual selection. Bite force of long‐tailed skink is positively correlated with larger body weight and head length, and the larger head can further enhance bite force for males in sexual selection. Bite force plays an important role both for inter‐ and intra‐specific interactions. Under extremely high predation risk from the reptile‐egg eating snake (Oligodon formosanus), long‐tailed skinks (Eutropis longicaudata) on Orchid Island display a unique egg‐guarding behavior, which drives larger bite force than in other populations without parental care. Males in three populations exhibit stronger bite force likely due to stronger sexual selection. Our study provides the first evidence that maternal care can drive higher bite force in lizards. Such higher bite force may have genetic‐based interaction, because in the same population, the males also have stronger bite force than in the other two male populations. [ABSTRACT FROM AUTHOR]

Many young females have difficulty opening jars. Although previous studies have attempted to clarify the body posture effect during such a task, the experiments therein focused on a single digit or actions with unnatural finger positions and were further restricted to upper extremity postures. A further study is required to investigate the fingers' coordination, as well as each subject's natural and self-selected upper extremity posture and finger grasp location when opening a jar. This study focused on the forces and coordination of the right hand fingers during a jar opening movement under both vertical and free-way opening postures. A jar simulator was set up to record the forces applied by finger groups (the thumb, the index-middle finger group, and the ring-little finger group) of the right hand. A self-selected finger position and free-arm posture of each subject were allowed. Results show that the force vectors of the finger groups were all in the counterclockwise direction for both postures. The total force and overall torque of the right hand decreased in the vertical opening posture. The thumb produced greater tangential and resultant forces in the vertical opening posture. Despite normal forces being 1.82-3.54 times the tangential forces for both postures, no difference was found for the normal force to tangential force ratio for each finger group between the two opening postures. The index-middle finger group had similar torque contributions for both postures. The torque contribution of the thumb increased (26% and 21% for vertical and free-way posture, respectively), while the ring-little finger group torque contribution decreased (35% and 42% for vertical and free-way posture, respectively) in the vertical opening posture. As such, the free-way opening posture is the better strategy for young females to open a jar. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Past studies have identified a number of distinct mechanisms that contribute to the resistance of melanoma cells against apoptosis induced by TNF-related apoptosis-inducing ligand (TRAIL). In this report we show that cystatin B is another endogenous inhibitor of TRAIL-induced apoptosis. Cystatin B-deficient melanoma cell lines established by shRNA knockdown displayed increased apoptosis that was associated with enhanced activation of caspase-8 induced by TRAIL. This was not related to the inhibitory effect of cystatin B on the lysosomal cysteine proteases, cathepsin B and L, as they did not have a role in TRAIL-induced apoptosis in most melanoma cell lines even when cystatin B was inhibited. Instead, sensitization of melanoma cells to TRAIL-induced apoptosis by inhibition of cystatin B appeared associated with decreased stability of FLIPL as the levels of FLIPL were reduced because of shortened half-life time in melanoma cells deficient in cystatin B. In contrast, over-expression of cystatin B increased the levels of FLIPL, decreased the amount of the E3 ligase Itch associated with FLIPL, and reduced FLIPL ubiquitination. Inhibition of Itch by siRNA restored the levels of FLIPL and blocked sensitization to TRAIL-induced apoptosis associated with deficiency in cystatin B. Taken together, these results indicate that cystatin B regulates Itch-mediated degradation of FLIPL and thereby TRAIL-induced apoptosis in melanoma cells. [ABSTRACT FROM AUTHOR]