New approach of monitoring changes in chlorophyll a fluorescence of single guard cells and protoplasts in response to physiological stimuli

A new type of microfluorometer was applied to assess photosynthesis at the single-cell level by chlorophyll fluorescence using the saturation pulse method. A microscopy–pulse amplitude modulation (PAM) chlorophyll fluorometer was combined with a Zeiss Axiovert 25 inverted epifluorescence microscope for high-resolution measurements on single mesophyll and guard cells and the respective protoplasts. Available information includes effective quantum yield of photosystem II, relative electron transport rate and energization of the thylakoid membrane due to the transthylakoidal proton gradient. Dark–light induction curves of guard cell (GCPs) and mesophyll cell protoplasts (MCPs) displayed very similar characteristics, indicating similar functional organization of thylakoid membranes in both types of chloroplasts. Light response curves, however, revealed much earlier saturation of photosynthetic electron flow in GCPs than in MCPs. Under anaerobiosis, photosynthetic electron flow and membrane energization were severely suppressed. A similar effect was observed in guard cells when epidermal peels were incubated with the fungal toxin fusicoccin which activates the plasma membrane H⁺-ATPase and causes irreversible opening of stomata. The drop in electron transport rate was prevented by blocking ATP consumption of the H⁺ pump or by glucose addition. These results show that chlorophyll fluorescence quenching analysis allows profound insights into stomatal physiology.     

Recent Advances in Understanding Proteins Involved in Lipid Droplet Formation,Growth and Fusion

Lipid droplets （LDs） were once viewed as simple, inert lipid micelles. However, they are now known to be organelles with a rich proteome involved in a myriad of cellular processes. LDs are heterogeneous in nature with different sizes and compositions of phospholipids, neutral lipids and proteins. This review takes a focused look at the roles of proteins involved in the regulation of LD formation, expansion, and morphology. The related proteins are summarized such as the fat-specific protein （Fsp27）, fat storage-inducing trans- membrane （FIT） proteins, seipin and ADP-ribosylation factor 1-coat protein complex I （Arf-COPI）. Finally, we present important challenges in LD biology for a deeper understanding of this dynamic organelle to be achieved.     

Influence of different macronutrient solutions and growth regulators on micropropagation of juvenile shape Acacia mangium and shape Paraserianthes falcataria explants

The influence of five different macronutrient formulations and various growth regulators on micropropagation of single node explants from Acacia mangium and Paraserianthes falcataria seedlings was examined after 4 weeks and 8 weeks in vitro. The experiment was repeated 4 months later. On media lacking growth regulators, growth and development were significantly influenced by the different macronutrient solutions tested, although morphogenic responses could vary according to the species. For instance, P. falcataria displayed a greater ability for adventitious rooting than A. mangium. Overall, Knop macronutrient solution induced the weakest responses. Explant responsiveness was significantly influenced by the addition of 2.2 or 4.4 μM 6-benzyladenine combined with either 1.4 or 2.3 μM kinetin, 1.5 or 2.5 μM indolebutyric acid or 1.6 or 2.7 μM naphthaleneacetic acid. The various combinations of growth regulators tested were shown to inhibit the rooting ability of the explants, while stimulating the production of basal shoots for both species, and of axillary shoots only for A. mangium. In such experimental conditions, A. mangium displayed overall a greater potential for micropropagation than P. falcataria. This revised version was published online in June 2006 with corrections to the Cover Date.     

Scabies and Bacterial Superinfection among American Samoan Children, 2011–2012

BackgroundScabies, a highly pruritic and contagious mite infestation of the skin, is endemic among tropical regions and causes a substantial proportion of skin disease among lower-income countries. Delayed treatment can lead to bacterial superinfection, and treatment of close contacts is necessary to prevent reinfestation. We describe scabies incidence and superinfection among children in American Samoa (AS) to support scabies control recommendations.Conclusions/SignificanceScabies and its sequelae cause substantial morbidity among AS children. Bacterial superinfection prevalence and frequent reinfestations highlight the importance of diagnosing scabies and early treatment of patients and close contacts. Investigating why certain AS counties have a lower scabies incidence might help guide recommendations for improving scabies control among counties with a higher incidence. We recommend interventions targeting infants and young children who have frequent close family contact.     

Modeling Nociception in Zebrafish: A Way Forward for Unbiased Analgesic Discovery

Acute and chronic pain conditions are often debilitating, inflicting severe physiological, emotional and economic costs and affect a large percentage of the global population. However, the development of therapeutic analgesic agents based primarily on targeted drug development has been largely ineffective. An alternative approach to analgesic development would be to develop low cost, high throughput, untargeted animal based behavioral screens that model complex nociceptive behaviors in which to screen for analgesic compounds. Here we describe the development of a behavioral based assay in zebrafish larvae that is effective in identifying small molecule compounds with analgesic properties. In a place aversion assay, which likely utilizes supraspinal neuronal circuitry, individually arrayed zebrafish larvae show temperature-dependent aversion to increasing and decreasing temperatures deviating from rearing temperature. Modeling thermal hyperalgesia, the addition of the noxious inflammatory compound and TRPA1 agonist allyl isothiocyanate sensitized heat aversion and reversed cool aversion leading larvae to avoid rearing temperature in favor of otherwise acutely aversive cooler temperatures. We show that small molecules with known analgesic properties are able to inhibit acute and/or sensitized temperature aversion.     

trans-Activation of the human T-cell leukemia virus long terminal repeat correlates with expression of the x-lor protein.

Cell lines established directly from adult T-cell leukemia-lymphoma patients or immortalized by human T-cell leukemia virus type I (HTLV-I) in vitro that do not produce complete HTLV virions were characterized both for the content of viral proteins and for the presence of trans-acting factors activating gene expression under the control of the HTLV long terminal repeat. The expression of the 42-kilodalton HTLV x-lor product correlated with trans-activation of the long terminal repeat. The implications of this study for understanding the role of the HTLV x-lor product in the initiation and maintenance of T-lymphocyte transformation are discussed.     

Expression of the x-lor gene of human T-cell leukemia virus I in Escherichia coli.

The 3'-terminal regions of the human T-cell leukemia virus I (HTLV-I) and HTLV-II genomes encode a novel gene product. We showed that expression of this region fused to the beta-galactosidase gene in bacteria produces a protein recognized by adult T-cell leukemia-lymphoma patient sera. Rabbit antibodies raised against this protein specifically precipitated the 42-kilodalton x-lor gene protein from HTLV-I-infected cells.     

Photosynthetic Carbon Assimilation in a Shootless Orchid, Chiloschista usneoides (DON) LDL: A Variant on Crassulacean Acid Metabolism

Photosynthetic carbon assimilation in the roots of a shootless orchid Chiloschista usneoides (DON) LDL involves the synthesis and accumulation of malic acid from CO₂ in darkness. Malic acid is consumed in the light.

The roots do not possess stomata or any means of diurnally regulating the diffusive conductance of the pathway between the internal gas phase of the plant and the atmosphere. Regulation of internal CO₂ concentration near to atmospheric levels avoids a large net loss of CO₂ to the atmosphere during malic acid consumption in the light.

The water-absorbing function of the velamen conflicts with the photosynthetic function of the roots. Plants with water-saturated velamina do not acquire CO₂ from the atmosphere at night.