Effects of 12‐Hour Rotating Shifts on Menstrual Cycles of Photoelectronic Workers in Taiwan

12 h rotating shifts are common in high‐tech industries in Taiwan. The aim of this longitudinal study was to evaluate the effect of the disruption of circadian rhythms by the shift schedule on menstrual cycle length (MCL) and regularity of female workers at an optoelectronic company in Taiwan. We recruited females who worked rotating shifts in a clean room environment as the shift‐work group and female office workers who worked normal business hours as the comparison group. Every participant recorded their MCL for each menstruation cycle up to eight consecutive months prospectively and provided demographic characteristics, reproductive history, and menstrual characteristics. We collected data on 1,135 and 117 menstruation cycles in the shift‐work (n=280) and comparison groups (n=49). Whereas the two groups had similar group means for MCL and number of menstrual bleeding days, the prevalence of menstrual cycle irregularity (cycles<25 or>35 days) was higher in the shift‐work group (p=0.04). Univariate and multivariate logistic regression analyses demonstrated that rotating shift work was an independent predictor of menstrual cycle irregularity (odds ratio=1.71, 95% confidence interval: 1.03–2.88) after adjusting for shift‐work history, employment duration, coffee consumption, and pre‐employment menstrual cycle irregularity. Although further study is required to confirm our findings plus to explore prevention and control measures, our data indicate rotating shift work can increase the risk of MCL irregularity.     

Genetic analysis of barrel field size in the first somatosensory area (SI) in inbred and recombinant inbred strains of mice

We measured the combined area of posterior medial barrel subfield (PMBSF) and anterior lateral barrel subfield (ALBSF) areas in four common inbred strains (C3H/HeJ, A?/J, C57BL?/6J, DBA/2J), B6D2F1, and ten recombinant inbred (RI) strains generated from C57BL/6J and DBA/2J progenitors (BXD) as an initial attempt to examine the genetic influences underlying natural variation in barrel field size in adult mice. These two subfields are associated with the representation of the whisker pad and sinus hairs on the contralateral face. Using cytochrome oxidase labeling to visualize the barrel field, we measured the size of the combined subfields in each mouse strain. We also measured body weight and brain weight in each strain. We report that DBA/2J mice have a larger combined PMBSF/ALBSF area (6.15?±?0.10?mm²,?n?=?7) than C57BL?/6J (5.48?±?0.13?mm²,?n?=?10), C3H/HeJ (5.37?±?0.16?mm²,?n?=?10), and A/J mice (5.04?±?0.09?mm²,?n?=?15), despite the fact that DBA/2J mice have smaller average brain and body sizes. This finding may reflect dissociation between systems that control brain size with those that regulate barrel field area. In addition, BXD strains (average n?=?4) and parental strains showed considerable and continuous variation in PMBSF/ALBSF area, suggesting that this trait is polygenic. Furthermore, brain, body, and cortex weights have heritable differences between inbred strains and among BXD strains. PMBSF/ALBSF pattern appears similar among inbred and BXD strains, suggesting that somatosensory patterning reflects a common plan of organization. This data is an important first step in the quantitative genetic analysis of the parcellation of neocortex into diverse cytoarchitectonic zones that vary widely within and between species, and in identifying the genetic factors underlying barrel field size using quantitative trait locus (QTL) analyses.     

Variation in embolism occurrence and repair along the stem in drought‐stressed and re‐watered seedlings of a poplar clone

Root pressure and plasma membrane intrinsic protein (PIP) availability in the xylem have been recognized to participate in the refilling of embolized conduits, yet integration of the two mechanisms has not been reported in the same plant. In this study, 4‐month‐old seedlings of a hybrid poplar (Populus alba × Populus glandulosa) clone 84K were subjected to two contrasting soil‐water treatments, with the drought treatment involving withholding of water for 17 days to reduce the soil‐water content to 10% of the saturated field capacity, followed by a re‐watering cycle. The percentage loss of stem hydraulic conductance (PLC) sharply increased, and stomatal conductance and photosynthesis declined in response to drought stress; these processes were gradually restored following the subsequent re‐watering. Embolism was most severe in the middle portions of the stem, followed by the basal and top portions of the stems of seedlings subjected to drought stress and subsequent re‐watering. Although drought stress eliminated root pressure, re‐watering partially restored it in a short period of time. The expression of PIP genes in the xylem was activated by drought stress, and some PIP genes were further stimulated in the top portion after re‐watering. The dynamics of root pressure and differential expression of PIP genes along the stem coincided with changes in PLC, suggesting that root pressure and PIPs work together to refill the embolized vessels. On the basis of the recovery dynamics in PLC and g_smax (maximum stomatal conductance) after re‐watering, the stomatal closure and xylem cavitation exhibited fatigue due to drought stress.     

MAIGO2 is involved in abscisic acid‐mediated response to abiotic stresses and Golgi‐to‐ER retrograde transport

The central role of multisubunit tethering complexes in intracellular trafficking has been established in yeast and mammalian systems. However, little is known about their roles in the stress responses and the early secretory pathway in Arabidopsis. In this study, Maigo2 (MAG2), which is equivalent to the yeast Tip20p and mammalian Rad50‐interacting protein, is found to be required for the responses to salt stress, osmotic stress and abscisic acid in seed germination and vegetative growth, and MAG2‐like (MAG2L) is partially redundant with MAG2 in response to environmental stresses. MAG2 strongly interacts with the central region of ZW10, and both proteins are important as plant endoplasmic reticulum (ER)‐stress regulators. ER morphology and vacuolar protein trafficking are unaffected in the mag2, mag2l and zw10 mutants, and the secretory marker to the apoplast is correctly transported in mag2 plants, which indicate that MAG2 functions as a complex with ZW10, and is potentially involved in Golgi‐to‐ER retrograde trafficking. Therefore, a new role for ER–Golgi membrane trafficking in abiotic‐stress and ER‐stress responses is discovered.     

Vascular Occlusions in Grapevines with Pierce’s Disease Make Disease Symptom Development Worse

Vascular occlusions are common structural modifications made by many plant species in response to pathogen infection. However, the functional role(s) of occlusions in host plant disease resistance/susceptibility remains controversial. This study focuses on vascular occlusions that form in stem secondary xylem of grapevines (Vitis vinifera) infected with Pierce’s disease (PD) and the impact of occlusions on the hosts’ water transport and the systemic spread of the causal bacterium Xylella fastidiosa in infected vines. Tyloses are the predominant type of occlusion that forms in grapevine genotypes with differing PD resistances. Tyloses form throughout PD-susceptible grapevines with over 60% of the vessels in transverse sections of all examined internodes becoming fully blocked. By contrast, tylose development was mainly limited to a few internodes close to the point of inoculation in PD-resistant grapevines, impacting only 20% or less of the vessels. The extensive vessel blockage in PD-susceptible grapevines was correlated to a greater than 90% decrease in stem hydraulic conductivity, compared with an approximately 30% reduction in the stems of PD-resistant vines. Despite the systemic spread of X. fastidiosa in PD-susceptible grapevines, the pathogen colonized only 15% or less of the vessels in any internode and occurred in relatively small numbers, amounts much too small to directly block the vessels. Therefore, we concluded that the extensive formation of vascular occlusions in PD-susceptible grapevines does not prevent the pathogen’s systemic spread in them, but may significantly suppress the vines’ water conduction, contributing to PD symptom development and the vines’ eventual death.Pierce’s disease (PD) of grapevines (Vitis vinifera), currently jeopardizing the wine and table grape industries in the southern United States and California, as well as in many other countries, is a vascular disease caused by the xylem-limited bacterium Xylella fastidiosa (Hopkins, 1989; Varela et al., 2001). The pathogen is transmitted mostly via xylem sap-feeding sharpshooters (e.g. Homalodisca vitripennis; Redak et al., 2004) and inhabits, proliferates, and spreads within the vessel system of a host grapevine (Fry and Milholland, 1990a; Hill and Purcell, 1995). PD symptom development in grapevines depends on the interactions between the pathogen and the host vine’s xylem tissue, through which the pathogen may achieve its systemic spread (Purcell and Hopkins, 1996; Krivanek and Walker, 2005; Pérez-Donoso et al., 2010; Sun et al., 2011). Since the path for this spread is the host’s xylem system, xylem tissue and its vessels have become the major focus for studying potential X. fastidiosa-host vine interactions at the cellular or tissue levels (Fry and Milholland, 1990b; Stevenson et al., 2004a; Sun et al., 2006, 2007; Thorne et al., 2006).One major issue related to this host-pathogen interaction is the relationship of a vine’s xylem anatomy to the X. fastidiosa population’s spread. Sun et al. (2006) did a detailed anatomical analysis of the stem secondary xylem, especially the vessel system. Stevenson et al. (2004b) described xylem connection patterns between a stem and the attached leaves. Other studies reported the presence of open continuous vessels connecting stems and leaves, which represent conduits that might facilitate the pathogen’s stem-to-leaf movement (Thorne et al., 2006; Chatelet et al., 2006, 2011). Chatelet et al. (2011) also suggested that vessel size and ray density were the two xylem features that were most relevant to the restriction of X. fastidiosa’s movement. These studies indicate the importance of understanding the grapevine’s xylem anatomy in order to characterize the grapevine host’s susceptibility or resistance to PD.Another focus of PD-related xylem studies is the tylose, a developmental modification that has important impacts on a vessel’s role in water transport and, potentially, its availability as a path for X. fastidiosa’s systemic spread through a vine. Tyloses are outgrowths into a vessel lumen from living parenchyma cells that are adjacent to the vessel and can transfer solutes into the transpiration stream via vessel-parenchyma (V-P) pit pairs (Esau, 1977). Tylose development involves the expansion of the portions of the parenchyma cell’s wall that are shared with the neighboring vessels, specifically the so-called pit membranes (PMs). Intensive tylose development may eventually block the affected vessel (Sun et al., 2006). Since tyloses occur in the vessel system of PD-infected grapevines (Esau, 1948; Mollenhauer and Hopkins, 1976; Stevenson et al., 2004a; Krivanek et al., 2005) that is also the avenue of X. fastidiosa’s spread and water transport, a great deal of effort has been made to understand tyloses and their possible relations to grapevine PD as well as to diseases caused by other vascular system-localized pathogens. One major aspect is to clarify the process of tylose development itself, in which an open vessel may be gradually sealed (Sun et al., 2006, 2008). Our investigations of the initiation of tylose formation in grapevines have identified ethylene as an important factor (Pérez-Donoso et al., 2007; Sun et al., 2007). In terms of the relationship of tyloses to grapevine PD, studies have so far led to several controversial viewpoints that are discussed below (Mollenhauer and Hopkins, 1976; Fry and Milholland, 1990b; Stevenson et al., 2004a; Krivanek et al., 2005). However, more convincing evidence is still needed to support any of them.Another issue potentially relevant to PD symptom development is the possibility that X. fastidiosa cells and/or their secretions contribute to the blockage of water transport in host vines. The bacteria secrete an exopolysaccharide (Roper et al., 2007a) that contributes to the formation of cellular aggregates. Accumulations of X. fastidiosa cells embedded in an exopolysaccharide matrix (occasionally identified as biofilms, gums, or gels) have been reported in PD-infected grapevines (Mollenhauer and Hopkins, 1974; Fry and Milholland, 1990a; Newman et al., 2003; Stevenson et al., 2004b). However, a more detailed investigation is still needed to clarify if and to what extent these aggregates affect water transport in infected grapevines.The xylem tissue in which X. fastidiosa spreads can be classified as primary xylem or secondary xylem, being derived from procambium or vascular cambium, respectively. Primary xylem is located in and responsible for material transport and structural support in young organs (i.e. leaves, young stems, and roots), while secondary xylem is the conductive and supportive tissue in more mature stems and roots (Esau, 1977). It should be noted that most of the earlier experimental results have been based on examinations of leaves (petioles or veins) or young stems of grapevines, which contain mostly primary xylem with little or no secondary xylem. However, X. fastidiosa’s systemic spread generally occurs after introduction during the insect vector’s feeding from an internode of one shoot. The pathogen then moves upward along that shoot and also downward toward the shoot base. The downward movement allows the bacteria to enter the vine’s other shoots via the shared trunk and then move upward (Stevenson et al., 2004a; Sun et al., 2011). These upward and downward bacterial movements occur through stems that contain significant amounts of secondary xylem but relatively dysfunctional primary xylem. Secondary and primary xylem show some major differences in the structure and arrangement of their cell components (Esau, 1977). In terms of the vessel system that is the path of X. fastidiosa’s spread, the secondary xylem has a large number of much bigger vessels with scalariform (ladder-like) PMs (and pit pairs) as the sole intervessel (I-V) PM type, compared with the primary xylem, which contains only a limited number of smaller vessels with multiple types of I-V PMs (Esau, 1948; Sun et al., 2006). Vessels in secondary xylem are also different from those in primary xylem in forming vessel groups and in the number of parenchyma cells associated with a vessel (as seen in transverse sections of xylem tissue). These features of secondary xylem can affect the initial entry and subsequent I-V movement of the pathogen and the formation of vascular occlusions, respectively, in stems containing significant amounts of secondary xylem. Recently, the X. fastidiosa population size only in stems with secondary xylem was found to correlate with the grapevine’s resistance to PD (Baccari and Lindow, 2011), indicating an important role of stem secondary xylem in determining a host vine’s disease resistance. Despite these facts, little is known about the pathogen-grapevine interactions in the stem secondary xylem and their possible impacts on disease development.This study addresses X. fastidiosa-grapevine interactions in stem secondary xylem and examines the resulting impacts on overall vine physiology, with a primary focus on vine water transport. We have made use of grapevine genotypes displaying different PD resistances and explored whether differences in the pathogen’s induction of vascular occlusions occur among the genotypes and, if so, how the differences impact X. fastidiosa’s systemic spread. Our overall, longer-term aim is to elucidate the functional role of vascular occlusions in PD development, an understanding that we view to be essential for identifying effective approaches for controlling this devastating disease.     

Function of wheat phosphate transporter gene TaPHT2;1 in Pi translocation and plant growth regulation under replete and limited Pi supply conditions

Several phosphate transporters (PTs) that belong to the Pht2 family have been released in bioinformatics databases, but only a few members of this family have been functionally characterized. In this study, we found that wheat TaPHT2;1 shared high identity with a subset of Pht2 in diverse plants. Expression analysis revealed that TaPHT2;1 was strongly expressed in the leaves, was up-regulated by low Pi stress, and exhibited a circadian rhythmic expression pattern. TaPHT2;1–green fluorescent protein fusions in the leaves of tobacco and wheat were specifically detected in the chloroplast envelop. TaPHT2;1 complemented the Pi transporter activities in a yeast mutant with a defect in Pi uptake. Knockdown expression of TaPHT2;1 significantly reduced Pi concentration in the chloroplast under sufficient (2 mM Pi) and deficient Pi (100 μM Pi) conditions, suggesting that TaPHT2;1 is crucial in the mediation of Pi translocation from the cytosol to the chloroplast. The down-regulated expression of TaPHT2;1 resulted in reduced photosynthetic capacities, total P contents, and accumulated P amounts in plants under sufficient and deficient Pi conditions, eventually leading to worse plant growth phenotypes. The TaPHT2;1 knockdown plants exhibited pronounced decrease in accumulated phosphorus in sufficient and deficient Pi conditions, suggesting that TaPHT2;1 is an important factor to associate with a distinct P signaling that up-regulates other PT members to control Pi acquisition and translocation within plants. Therefore, TaPHT2;1 is a key member of the Pht2 family involved in Pi translocation, and that it can function in the improvement of phosphorus usage efficiency in wheat.     

Foot-and-Mouth Disease Virus Modulates Cellular Vimentin for Virus Survival

Foot-and-mouth disease virus (FMDV), the causative agent of foot-and-mouth disease, is an Aphthovirus within the Picornaviridae family. During infection with FMDV, several host cell membrane rearrangements occur to form sites of viral replication. FMDV protein 2C is part of the replication complex and thought to have multiple roles during virus replication. To better understand the role of 2C in the process of virus replication, we have been using a yeast two-hybrid approach to identify host proteins that interact with 2C. We recently reported that cellular Beclin1 is a natural ligand of 2C and that it is involved in the autophagy pathway, which was shown to be important for FMDV replication. Here, we report that cellular vimentin is also a specific host binding partner for 2C. The 2C-vimentin interaction was further confirmed by coimmunoprecipitation and immunofluorescence staining to occur in FMDV-infected cells. It was shown that upon infection a vimentin structure forms around 2C and that this structure is later resolved or disappears. Interestingly, overexpression of vimentin had no effect on virus replication; however, overexpression of a truncated dominant-negative form of vimentin resulted in a significant decrease in viral yield. Acrylamide, which causes disruption of vimentin filaments, also inhibited viral yield. Alanine scanning mutagenesis was used to map the specific amino acid residues in 2C critical for vimentin binding. Using reverse genetics, we identified 2C residues that are necessary for virus growth, suggesting that the interaction between FMDV 2C and cellular vimentin is essential for virus replication.     

Synergistic roles of leaf boron and calcium during the growing season in affecting sugar and starch accumulation in ripening apple fruit

Fruit sugar content is one of the most important flavor quality traits in the fresh market. Minerals, such as boron (B) and calcium (Ca), are associated with fruit sugar and starch accumulation in many plant species. To better understand the roles of B and Ca in affecting sugar and starch accumulation in apples, 2 g L^?1 Na₂B₄O₇·10H₂O or 10 g L^?1 CaCl₂ was supplied by foliar spray to 20-year-old ‘Fuji’ (Malus domestica Borkh. cv. Fuji) trees at four developmental stages (fruit set, onset of rapid fruit growth, rapid fruit growth and the end of rapid fruit growth), in 2010–2011. The most effective treatment significantly increasing soluble sugar and starch levels in ripening fruit was the foliar application of 2 g L^?1 Na₂B₄O₇·10H₂O during rapid fruit growth, and the robustness of the effects was confirmed for two cultivars, ‘Fuji’ and ‘Orin’, at three orchards in 2011. Foliar applications of B during the onset of rapid fruit growth and rapid fruit growth, as well as the foliar application of Ca at fruit set, significantly increased the soluble sugar content in ripening fruit. In addition, the B application was effective in increasing the fruit starch content, but Ca was not. Both B and Ca treatments significantly increased the leaf concentrations of the other element at least transiently. However, B and Ca effects on fruit sugar/starch did not seem to depend on higher leaf B or Ca levels. In conclusion, B and Ca interact in enhancing fruit sugar and starch contents at the fruit ripening stage.