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The benthic ctenophore Vallicula multiformis Rankin, 1956 (Ctenophora, Platyctenida) was originally described from Jamaica. We found the species in an aquarium during our survey of jellyfish from Palawan Island, the Philippines. Molecular analysis of the species confirmed the morphology-based identification of the samples. This discovery is the first report of the occurrence of species from the western Pacific area. [ABSTRACT FROM AUTHOR]

Envenomation by toxic box jellyfish species is known to be a serious problem to public health. In order to elucidate the problem, it becomes necessary to predict the occurrence of box jellyfishes, as well as understanding their ecology and life cycle. Mature medusae of Carybdea brevipedalia (Cubozoa: Carybdeida), which is a common species of box jellyfish in Japan, were collected from northern Japan to observe its early life history, including polyp formation. Fertilization occurred externally, and blastulae developed into planulae. Free swimming planulae settled and metamorphosed into tiny primary polyps with two forms, i.e. settled and creeper. Adult polyps formed cysts at temperatures below 15°C or when water replacement and/or feeding was stopped. Budding occurred in four-tentacled polyps, and the buds were released after commencement of budding. Complete metamorphosis of a whole polyp into a single medusa occurred at stable temperatures between 18 to 25°C (18, 20, 23, 25°C, respectively) or when temperatures were raised from 20 to 25°C. Newly released medusae had four tentacles. Our study demonstrated that polyps of C. brevipedalia survive and propagate over a wide range of water temperatures and that developmental features resemble closely those of some tripedaliid species, namely Tripedalia cystophora and Copula sivickisi, rather than Carybdea marsupialis. The morphological affinities of polyp in C. brevipedalia, T. cystophora and C. sivickisi support recent molecular results. However, further studies are needed to confirm the morphological contradiction between C. brevipedalia and C. marsupialis in the future. [ABSTRACT FROM AUTHOR]

C4 plants have evolved >60 times from their C3 ancestors. C4 photosynthesis requires a set of closely co-ordinated anatomical and biochemical characteristics. However, it is now recognized that the evolution of C4 plants requires fewer changes than had ever been considered, because of the genetic, biochemical and anatomical pre-conditions of C3 ancestors that were recruited into C4 photosynthesis. Therefore, the pre-conditions in C3 plants are now being actively investigated to clarify the evolutionary trajectory from C3 to C4 plants and to engineer C4 traits efficiently into C3 crops. In the present mini review, the anatomical characteristics of C3 and C4 plants are briefly reviewed and the importance of the bundle sheath for the evolution of C4 photosynthesis is described. For example, while the bundle sheath of C3 rice plants accumulates large amounts of starch in the developing leaf blade and at the lamina joint of the mature leaf, the starch sheath function is also observed during leaf development in starch accumulator grasses regardless of photosynthetic type. The starch sheath function of C3 plants is therefore also implicated as a possible precondition for the evolution of C4 photosynthesis. The phylogenetic relationships between the types of storage carbohydrates and of photosynthesis need to be clarified in the future. [ABSTRACT FROM AUTHOR]

Mass aggregations of Aurelia limbata have been reported along the Pacific coast of northern Japan, from spring to fall. The polyp stage is important for understanding the factors leading to mass occurrences of jellyfish, because polyps reproduce asexually and are responsible for the release of many ephyrae. Until the present report, the polyps of A. limbata had not been found in the wild and their ecology remained unknown. We found 18 polyps of A. limbata attached to two pieces of deep-sea debris, an aluminum beverage can and a plastic bottle, collected by bottom trawl at depths of 296 m and 392 m, respectively. Strobilation of the polyps was observed at 4°C without temperature change stimulation. This raises the possibility that strobilation occurs in low-temperature environments throughout the year. A large quantity of debris had sunk to the seafloor off the coast because of the tsunami tidal wave after the Great East Japan Earthquake, increasing the available substrate for A. limbata polyps. Additional ecological research on polyps and medusae in deep waters is necessary to predict future blooms of A. limbata. [ABSTRACT FROM AUTHOR]

A new family, genus and species of cubozoan box jellyfish belonging to the order Chirodropida is reported from the eastern Japan. Meteorona kishinouyei gen. et sp. n. possesses the following unique morphological characters with respect to other known species in the Chirodropida: having one tentacle per scalpel-like unbranched pedalium and slightly raised unbranched gastric saccules. A comparative table of the primary diagnostic characters of genus and order in the Chirodropida is given. The order Chirodropida is redefined. The family Chiropsellidae is established. Discussion is provided on the implications for these findings on our current understanding of Cubozoan systematics. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) have recently been integrated with membrane bioreactors (MBRs) for wastewater treatment and energy recovery. However, the impact of integration of the two reactors on membrane fouling of MBR has not been reported yet. In this study, MFCs equipped with different external resistances (1-10 000 ohm) were operated, and membrane-fouling potentials of the MFC anode effluents were directly measured to study the impact of anodic respiration by exoelectrogens on membrane fouling. It was found that although the COD removal efficiency was comparable, the fouling potential was significantly reduced due to less production of biopolymer (a major foulant) in MFCs equipped with lower external resistance (i.e., with higher current generation) as compared with aerobic respiration. Furthermore, it was confirmed that Geobacter sulfurreducens strain PCA, a dominant exoelectrogen in anode biofilms of MFCs in this study, produced less biopolymer under anodic respiration condition than fumarate (anaerobic) respiration condition, resulting in lower membrane-fouling potential. Taken together, anodic respiration can mitigate membrane fouling of MBR due to lower biopolymer production, suggesting that development of an electrode-assisted MBR (e-MBR) without aeration is feasible. [ABSTRACT FROM AUTHOR]

The membranes of Zea mays (maize) mesophyll cell ( MC) chloroplasts are more vulnerable to salinity stress than are those of bundle sheath cell ( BSC) chloroplasts. To clarify the mechanism underlying this difference in salt sensitivity, we monitored changes in the glycerolipid and fatty acid compositions of both types of chloroplast upon exposure to salinity stress. The monogalactosyldiacylglycerol ( MGDG) and digalactosyldiacylglycerol ( DGDG) contents were higher in MC chloroplasts than in BSC chloroplasts, in both the presence and absence of salt treatment. Under salt conditions, the MGDG level in MC chloroplasts was significantly lower than under normal conditions, while it was unchanged in BSC chloroplasts. In both types of chloroplast, the contents of DGDG, phosphatidylglycerol and phosphatidylinositol remained at the same levels in control and salt-treated plants, whereas sulfoquinovosyldiacylglycerol and phosphatidylcholine were significantly lower and higher, respectively, upon salt treatment. In addition, the fatty acid composition and double bond index of individual lipid classes were changed by salt treatment in both BSC and MC chloroplasts, although these factors had no effect on glycerolipid content. These findings suggest that the difference in salt sensitivity of MC and BSC chloroplast membranes is related to differences in MGDG responses to salinity. Thus, we propose that the low MGDG content and the low sensitivity of MGDG to salinity in BSC chloroplasts render them more tolerant than MC chloroplasts to salinity stress. [ABSTRACT FROM AUTHOR]

We have investigated whether the overexpression of RCI2A gene causes an enhanced salt-tolerant phenotype in Arabidopsis thaliana. Although the growth of RCI2A-overexpressing transgenic plants was comparable with that of wild type under normal conditions, high salinity treatment caused decreased accumulation of Na+ and ameliorated suppression of the shoot growth of transgenic plants than that of wild type. Under high salinity treatment, the chlorophyll content of the shoots of wild-type plants significantly decreased compared with transgenic plants. The increases of malondialdehyde (MDA) and of H2O2 production caused by high salinity were greater in the shoots of wild type than in that of transgenic plants. These results suggest that overexpression of RCI2A can alleviate salinity-induced growth suppression and photooxidative damages via reducing Na+ uptake into the shoots. [ABSTRACT FROM AUTHOR]

The stings of box jellyfishes can be fatal, so knowing the fauna of a certain area is important to save lives. Five described and two still-undescribed species of Cubozoa have been reported from Thailand: Chironex indrasaksajiae, Chironex sp., Chiropsella sp., Chiropsoides buitendijki, Copula sivickisi, Morbakka fenneri, and Tripedalia cystophora. We made detailed observations of the morphology of two of the species newly recorded in Thailand: Alatina morandinii and Tripedalia binata. The molecular phylogeny of these species is also discussed. Additional investigations are needed to understand the diversity of Cubozoa in Thailand. [ABSTRACT FROM AUTHOR]

In this study, we investigated the trophic interactions between the Japanese giant box jellyfish, Morbakka virulenta, and fish in the central part of the Seto Inland Sea, western Japan, in autumn and winter. Occurring in the surface waters at nighttime, these cubomedusae, regardless of their size (1.5 to 22.5 cm in bell height), were found to be piscivorous, feeding mainly on the Japanese anchovy, as shown by their stomach contents analysis. This finding was supported by a stable isotopic analysis and by an unchanged cnidome, irrespective of the bell height of medusae. Their nocturnal occurrence near the surface often took place around the slack tide, during which the medusae were foraging with tentacles fully extended. Other associations between the medusae and fish were also observed at this time: presumed commensalism with juvenile Japanese horse mackerel, and predation by black scraper. [ABSTRACT FROM AUTHOR]

Acetylcholine (ACh), a known neurotransmitter in animals and acetylcholinesterase (AChE) exists widely in plants, although its role in plant signal transduction is unclear. We previously reported AChE in Zea mays L. might be related to gravitropism based on pharmacological study using an AChE inhibitor. Here we clearly demonstrate plant AChE play an important role as a positive regulator in the gravity response of plants based on a genetic study. First, the gene encoding a second component of the ACh-mediated signal transduction system, AChE was cloned from rice, Oryza sativa L. ssp. Japonica cv. Nipponbare. The rice AChE shared high homology with maize, siratro and Salicornia AChEs. Similar to animal and other plant AChEs, the rice AChE hydrolyzed acetylthiocholine and propionylthiocholine, but not butyrylthiocholine. Thus, the rice AChE might be characterized as an AChE (E.C.3.1.1.7). Similar to maize and siratro AChEs, the rice AChE exhibited low sensitivity to the AChE inhibitor, neostigmine bromide, compared with the electric eel AChE. Next, the functionality of rice AChE was proved by overexpression in rice plants. The rice AChE was localized in extracellular spaces of rice plants. Further, the rice AChE mRNA and its activity were mainly detected during early developmental stages (2 d-10 d after sowing). Finally, by comparing AChE up-regulated plants with wild-type, we found that AChE overexpression causes an enhanced gravitropic response. This result clearly suggests that the function of the rice AChE relate to positive regulation of gravitropic response in rice seedlings. [ABSTRACT FROM AUTHOR]

In maize, the structure of bundle sheath cell (BSC) chloroplasts is less subject to salinity stress than that of mesophyll cell (MC) chloroplasts. To elucidate the difference in sensitivity to salinity, antioxidant capacities and localization of reactive oxygen species were investigated in both chloroplasts. Transmission electron microscopic observation showed that O2− localization was found in both chloroplasts under salinity, but the accumulation was much greater in MC chloroplasts. H2O2 localization was observed only in MC chloroplasts of salt‐treated plants. In isolated chloroplasts, the activities of superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11) and dehydroascorbate reductase (DHAR, EC 1.8.5.1) were increased by salinity. While the enhancement of SOD activity was similar in both chloroplasts, the increase of APX and DHAR activities were more pronounced in BSC chloroplasts than in MC chloroplasts. Monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) and glutathione reductase (GR, EC 1.6.4.2) were undetectable in BSC chloroplasts, while they increased in MC chloroplasts under salinity. Although ascorbate content increased by salinity only in BSC chloroplasts, glutathione content increased significantly in both chloroplasts, and was higher in MC chloroplasts than in BSC chloroplasts. The content of thiobarbituric acid‐reactive substances, which is an indicator of lipid peroxidation, was significantly increased by salinity in both chloroplasts. These results suggested O2−‐scavenging capacity was comparable between both chloroplasts, whereas H2O2‐scavenging capacity was lower in MC chloroplasts than in BSC chloroplasts. Moreover, the increased lipid peroxidation under salinity was associated with the structural alteration in MC chloroplasts, while it had less impact on the structure of BSC chloroplasts. [ABSTRACT FROM AUTHOR]

The Arabidopsis thaliana K+ channel KAT1 has been suggested to have a key role in mediating the aperture of stomata pores on the surface of plant leaves. Although the activity of KAT1 is thought to be regulated by phosphorylation, the endogenous pathway and the primary target site for this modification remained unknown. In the present study, we have demonstrated that the C-terminal region of KAT1 acts as a phosphorylation target for the Arabidopsis calcium-independent ABA (abscisic acid)-activated protein kinase SnRK2.6 (Snf1-related protein kinase 2.6). This was confirmed by LC-MS/MS (liquid chromatography tandem MS) analysis, which showed that Thr306 and Thr308 of KAT1 were modified by phosphorylation. The role of these specific residues was examined by single point mutations and measurement of KAT1 channel activities in Xenopus oocyte and yeast systems. Modification of Thr308 had minimal effect on KAT1 activity. On the other hand, modification of Thr306 reduced the K+ transport uptake activity of KAT1 in both systems, indicating that Thr306 is responsible for the functional regulation of KAT1. These results suggest that negative regulation of KAT1 activity, required for stomatal closure, probably occurs by phosphorylation of KAT1 Thr306 by the stress-activated endogenous SnRK2.6 protein kinase. [ABSTRACT FROM AUTHOR]

We investigated the effects of drought stress on the ultrastructure of chloroplasts in rice plants. After the seedlings were grown in a glasshouse for 1 month, they were treated for drought stress using two methods. One drought treatment was imposed by reducing the water supply to the plants for 1 month. The other was imposed by withholding water for 2 weeks to examine the withering process of leaves by drought stress. The ultrastructural changes of chloroplasts in bundle sheath cells were more prominent than those in mesophyll cells under both drought stress treatments. Ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) content in bundle sheath chloroplasts reduced more dramatically than in mesophyll chloroplasts by drought stress. Although a slight swelling of thylakoids was sometimes observed in bundle sheath chloroplasts in moderate stress for 1 month, the thylakoids were less affected by drought stress than chloroplast envelope. These results suggest that chloroplasts in bundle sheath cells were more sensitive to drought stress than those in mesophyll cells and the thylakoids were less damaged by drought stress compared with chloroplast envelope. [ABSTRACT FROM AUTHOR]

In C4 plants, bundle sheath (BS) chloroplasts are arranged in the centripetal position or in the centrifugal position, although mesophyll (M) chloroplasts are evenly distributed along cell membranes. To examine the molecular mechanism for the intracellular disposition of these chloroplasts, we observed the distribution of actin filaments in BS and M cells of the C4 plants finger millet (Eleusine coracana) and maize (Zea mays) using immunofluorescence. Fine actin filaments encircled chloroplasts in both cell types, and an actin network was observed adjacent to plasma membranes. The intracellular disposition of both chloroplasts in finger millet was disrupted by centrifugal force but recovered within 2 h in the dark. Actin filaments remained associated with chloroplasts during recovery. We also examined the effects of inhibitors on the rearrangement of chloroplasts. Inhibitors of actin polymerization, myosin-based activities and cytosolic protein synthesis blocked migration of chloroplasts. In contrast, a microtubule-depolymerizing drug had no effect. These results show that C4 plants possess a mechanism for keeping chloroplasts in the home position which is dependent on the actomyosin system and cytosolic protein synthesis but not tubulin or light. [ABSTRACT FROM AUTHOR]