During infection of macrophages, the pathogenic bacterium Legionella pneumophila secretes effector proteins that induce the conversion of the plasma membrane-derived vacuole into an endoplasmic reticulum (ER)-like replicative vacuole. These ER-like vacuoles are ultimately fused with the ER, where the pathogen replicates. Here we show that the L. pneumophila effector Lpg1137 is a serine protease that targets the mitochondria and their associated membranes. Lpg1137 binds to and cleaves syntaxin 17, a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein that is known to participate in the regulation of mitochondrial dynamics through interaction with the mitochondrial fission factor Drp1 in fed cells and in autophagy through interaction with Atg14L and other SNAREs in starved cells. Cleavage of syntaxin 17 inhibits not only autophagy but also staurosporine-induced apoptosis occurring in a Bax, Drp1-dependent manner. Thus, L. pneumophila can shut down ER–mitochondria communication through cleavage of syntaxin 17.

Effects of canopy cover and seasonal reduction in rainfall on leaf phenology and leaf traits of the fern Oleandra pistillaris in a tropical montane forest, Indonesia

There are two trade-offs at the levels of leaves and crowns, i.e. assimilation capacity per leaf mass is greater for shorter-lived leaves, and unbranched species grow faster in height by allocating carbon more to trunk than to leaves and branches compared with highly branched species. The hypotheses were tested that the degree of branching (L TB ) correlates with leaf traits and that height growth rate is negatively correlated with the degree of branching and leaf life span (LLS) by examining saplings of five canopy and subcanopy species, two shrub species and one invasive subshrub species (Clidemia hirta) in a tropical rain forest, West Java, Indonesia. Of the eight species, the most branched and unbranched species were Castanopsis acuminatissima and Macaranga semiglobosa, respectively. Leaf traits examined were leaf size, LLS, leaf mass per area (LMA), leaf nitrogen concentration per mass (N mass ) and per area. LLS tended to be positively correlated with LMA, and negatively correlated with N mass . Leaf size was negatively correlated with L TB , but the other leaf traits were not correlated with L TB . The height growth of the eight species was low, irrespective of L TB and LLS, for understorey individuals. The height growth of gap individuals was negatively correlated with LLS for the eight species, and also negatively with L TB for the seven species other than one subshrub species. Thus, the degree of branching was correlated with leaf size only among the five leaf traits, and both leaf life span and the degree of branching affected the height growth of gap individuals, except for the subshrub species.

Crown architecture and leaf traits were investigated in understory saplings (17-233 cm tall) of Macaranga semiglobosa in a tropical montane forest in Indonesia. The crown of a M. semiglobosa sapling consists of only leaves without branches. The total number of leaves per sapling increased from 4 to 19 leaves with an increase in trunk height in the examined saplings. Leaf area index (total sapling leaf area divided by crown projection area) increased with trunk height because of the increase in the total number of leaves per sapling with trunk height. Thus, it is suggested that there is limitation to avoid selfshading. Leaf blade width was relatively constant from the top (the youngest leaf, leaf order 1) to the lowest (the oldest leaf) leaf. By contrast, petiole length increased from leaf order 1 to leaf order 6, and then remained relatively constant after leaf order 6. Vertical changes in the leaf mass per area within a crown showed a similar pattern to that of petiole length. Leaf nitrogen (a proxy of assimilation capacity) and chlorophyll (a proxy of light-harvesting ability) contents per leaf area increased from leaf order 1 to leaf order 4, remained high until leaf order 7, and then decreased after leaf order 7. The present study suggests that petioles of M. semiglobosa elongate for longer than the leaf blades and that leaf morphological and physiological traits are coupled with the degree of petiole elongation occurring with vertical position, and this might increase light-capture and nitrogen-use efficiencies.

We applied mobility restrictions on able-bodied subjects to simulate motor dysfunction and investigated the resulting effects on their wheelchair operation ability and mental state. The study simulated spinal cord injuries of the C8-T1 vertebrae. Each subject's torso was secured to a backsupport, while the soles of the feet were suspended. While these mobility restrictions were in place, the subjects ascended slopes at a variety of inclination angles, and we measured the motion, torque, and electromyogram during their wheelchair operations. As a result, applying the restrictions (1) increased handrim operating time, (2) reduced the backwards pulling motion by the upper arms, (3) suppressed trunk muscle activity, (4) increased the psychological burden during operations, and (5) resulted in balance being maintained by immobilizing the knee and ankle joints through the simultaneous operation of the vastus lateralis and gastrocnemius muscles because the torso could not lean forward. These results indicated that despite the compensatory motions, the mobility restricting method used in this study came close to simulating mobility difficulties.