TAXONOMIC REVISION OF THE DINOFLAGELLATE AMPHIDOMA CAUDATA: TRANSFER TO THE GENUS AZADINIUM (DINOPHYCEAE) AND PROPOSAL OF TWO VARIETIES,BASED ON MORPHOLOGICAL AND MOLECULAR PHYLOGENETIC ANALYSES1

The systematic position of Amphidoma caudata Halldal within the genus Amphidoma has remained uncertain as a result of its plate formula and the absence of molecular phylogenetic data. Also, this thecate dinoflagellate taxon has been used to designate two distinct morphotypes. The present study aims to clarify the generic affiliation of Amphidoma caudata and the taxonomic value of two different morphotypes M1 and M2. The new examination of the plate formula using SEM showed that it was the same for both morphotypes and that it corresponded to the tabulation of the recent erected genus Azadinium Elbrächter et Tillmann. Morphometric analysis, using cell size, length of apical projection in conjunction with the cell length, and the ratio of horn and spine showed that M1 and M2 formed two distinct groups. These results were supported by a molecular approach, revealing notable differences in the sequences of LSU rDNA and ITS region between these two morphotypes. Phylogenetic analyses inferred either from LSU and combined SSU, ITS region and COI data positioned M1 and M2 in a sister cluster of Azadinium species while Amphidoma languida Tillmann, Salas et Elbrächter, the only species of Amphidoma for which sequence data were available, was situated in a basal position of the Azadinium clade. Thus, we propose the transfer of Amphidoma caudata to the genus Azadinium and, consequently, the rehabilitation of the original tabulation of the genus Amphidoma Stein. To discriminate the two morphotypes, we propose a rank of variety with the following designations: Azadinium caudatum var. caudatum and Azadinium caudatum var. margalefii.     

Characterization and expression profile analysis of a sucrose synthase gene from common bean (Phaseolus vulgaris L.) during seed development

A full-length cDNA encoding common bean (Phaseolus vulgaris L.) sucrose synthase (designated as Pv_BAT93 Sus), which catalyses the synthesis and cleavage of sucrose, was isolated from seeds at 15 days after pollination (DAP) by rapid amplification of cDNA ends (RACE). The full-length cDNA of Pv_BAT93 Sus had a 2,418 bp open reading frame (ORF) encoding a protein of 806 amino acid residues. Sequence comparison analysis showed that Pv_BAT93 Sus was very similar to several members of the sucrose synthase family of other plant species. Tissue expression pattern analysis showed that Pv_BAT93 Sus was expressed in leaves, flowers, stems, roots, cotyledons, and particularly during seed development. Expression studies using in situ hybridization revealed altered spatial and temporal patterns of Sus expression in the EMS mutant relative to wild-type and confirmed Sus expression in common bean developing seeds. The expression and accumulation of Sus mRNA was clearly shown in several tissues, such as the suspensor and embryo, but also in the transfer cells and endothelium. The results highlight the diverse roles that Sus might play during seed development in common bean.     

Iron and vitamin status biomarkers and its association with physical fitness in adolescents: the HELENA study

There is a lack of studies that analyze the association between micronutrient-related biomarker status and physical fitness in adolescents. In the present study, biochemical parameters for iron and vitamin status were studied, along with objective measures of physical fitness in healthy male and female European adolescents. One thousand eighty-nine adolescents (580 girls, 12.5-17.5 yr) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) cross-sectional study were included. Hierarchical linear models were performed to determine the associations between micronutrient biomarkers and physical fitness. Age, seasonality, latitude, body mass index, menarche (in girls), and physical activity were used as covariates. For cardiorespiratory fitness, concentrations of hemoglobin, retinol, and vitamin C in male adolescents and β-carotene and 25(OH)D in female adolescents were associated with maximal oxygen consumption. For muscular fitness, concentrations of hemoglobin, β-carotene, retinol, and α-tocopherol in male adolescents and β-carotene and 25(OH)D in female adolescents were associated with better performance of the standing long jump test. In summary, concentrations of hemoglobin and most antioxidant vitamins in male adolescents and β-carotene and 25(OH)D in female adolescents were positively associated with cardiorespiratory and muscular fitness, after controlling for relevant confounders. The associations between physical fitness and iron or vitamin status observed in this cross-sectional study in adolescents should be followed up by a study specifically designed to evaluate causal relationships.     

Assessment of upper airway dynamics by anterior magnetic phrenic stimulation in conscious sleep apnea patients

Phrenic nerve magnetic stimulation (PNMS) performed anterolaterally at the base of the neck (BAMPS) and cervical magnetic stimulation are common techniques for assessing upper airway (UA) mechanical properties in conscious humans. We considered that if NMS performed at the sternal level (a-MS) could induce a similar percentage of flow-limited twitches as BAMPS in conscious subjects, gauging UA dynamic properties by PNMS would be simplified. Instantaneous flow, pharyngeal and esophageal pressures, as well as thoraco-abdominal motion were recorded in 10 conscious sleep apnea patients. BAMPS and a-MS were applied at end expiration. The percentage of flow-limited twitches, maximal tolerated intensity, and minimal stimulator output associated with flow-limited twitches were similar between BAMPS and a-MS. Examining the effects of stimulation site, stimulation intensity and site*intensity interaction on the characteristics of flow-limited twitches, the former was responsible for more negative peak esophageal pressure (BAMPS: -11.5 ± 0.9 cmH(2)O; a-MS: -6.5 ± 1.1 cmH(2)O; P = 0.002) and UA closing pressure (BAMPS: -7.7 ± 0.5 cmH(2)O; a-MS: -5.8 ± 0.6 cmH(2)O; P = 0.02) as well as for lower mean linear upper airway resistance (UAR) (BAMPS 3.5 ± 0.4 cmH(2)O·l(-1)·s(-1); a-MS 2.2 ± 0.4 cmH(2)O·l(-1)·s(-1); P = 0.02). a-MS systematically evoked outward/inward thoracic displacement, although this movement pattern was observed in only 50% of patients when they were subjected to BAMPS. Linear UAR of BAMPS-induced flow-limited twitches was lower in the presence of initial outward thoracic movement (2 ± 0.05 cmH(2)O·l(-1)·s(-1)) than with inward motion (4.3 ± 1.5 cmH(2)O·l(-1)·s(-1); P = 0.03). We conclude that a-MS represents a practical and functional technique to evaluate UA mechanical properties in conscious sleep apnea patients.     

Redistribution of carbon and nitrogen through irrigation in intensively cultivated tropical mountainous watersheds

This study aimed at tracing and quantifying organic carbon and total nitrogen fluxes related to suspended material in irrigation water in the uplands of northwest Vietnam. In the study area, a reservoir acts as a sink for sediments from the surrounding mountains, feeding irrigation channels to irrigate lowland paddy systems. A flow separation identified the flow components of overland flow, water release from the reservoir to the irrigation channel, direct precipitation into the channel, irrigation discharge to paddy fields and discharge leaving the sub-watershed. A mixed effects model was used to assess the C and N loads of each flow component. Irrigation water had an average baseline concentration of 29?±?4.4?mg?l^?1 inorganic C, 4.7?±?1.2?mg?l^?1 organic C and 3.9?±?1.6?mg?l^?1 total N. Once soils were rewetted and overland flow was induced, organic C and total N concentrations changed rapidly due to increasing sediment loads in the irrigation water. Summarizing all monitored events, overland flow was estimated to convey about 63?kg organic C ha^?1 and 8.5?kg?N?ha^?1 from surrounding upland fields to the irrigation channel. The drainage of various non-point sources towards the irrigation channel was supported by the variation of the estimated organic C/total N ratios of the overland flow which fluctuated between 2 and 7. Nevertheless, the majority of the nutrient loads (up to 93–99%) were derived from the reservoir, which served as a sediment-buffer trap. Due to the overall high nutrient and sediment content of the reservoir water used for irrigation, a significant proportion of nutrients was continuously reallocated to the paddy fields in the lowland throughout the rice cropping season. The cumulative amount of organic C and total N load entering paddies with the irrigation water between May and September was estimated at 0.8 and 0.7?Mg?ha^?1, respectively. Therefore deposition of C and N through irrigation is an important contributor in maintaining soil fertility, and a process to be taken into account in the soil fertility management in these paddy rice systems.     

RNF8- and RNF168-dependent degradation of KDM4A/JMJD2A triggers 53BP1 recruitment to DNA damage sites

In response to DNA damage, cells initiate complex signalling cascades leading to growth arrest and DNA repair. The recruitment of 53BP1 to damaged sites requires the activation of the ubiquitination cascade controlled by the E3 ubiquitin ligases RNF8 and RNF168, and methylation of histone H4 on lysine 20. However, molecular events that regulate the accessibility of methylated histones, to allow the recruitment of 53BP1 to DNA breaks, are unclear. Here, we show that like 53BP1, the JMJD2A (also known as KDM4A) tandem tudor domain binds dimethylated histone H4K20; however, JMJD2A is degraded by the proteasome following the DNA damage in an RNF8-dependent manner. We demonstrate that JMJD2A is ubiquitinated by RNF8 and RNF168. Moreover, ectopic expression of JMJD2A abrogates 53BP1 recruitment to DNA damage sites, indicating a role in antagonizing 53BP1 for methylated histone marks. The combined knockdown of JMJD2A and JMJD2B significantly rescued the ability of RNF8- and RNF168-deficient cells to form 53BP1 foci. We propose that the RNF8-dependent degradation of JMJD2A regulates DNA repair by controlling the recruitment of 53BP1 at DNA damage sites.