The rice (Oryza sativa) spotted leaf11 (spl11) mutant was identified from an ethyl methanesulfonate-mutagenized indica cultivar IR68 population and was previously shown to display a spontaneous cell death phenotype and enhanced resistance to rice fungal and bacterial pathogens. Here, we have isolated Spl11 via a map-based cloning strategy. The isolation of the Spl11 gene was facilitated by the identification of three additional spl11 alleles from an IR64 mutant collection. The predicted SPL11 protein contains both a U-box domain and an armadillo (ARM) repeat domain, which were demonstrated in yeast and mammalian systems to be involved in ubiquitination and protein-protein interactions, respectively. Amino acid sequence comparison indicated that the similarity between SPL11 and other plant U-box-ARM proteins is mostly restricted to the U-box and ARM repeat regions. A single base substitution was detected in spl11, which results in a premature stop codon in the SPL11 protein. Expression analysis indicated that Spl11 is induced in both incompatible and compatible riceblast interactions. In vitro ubiquitination assay indicated that the SPL11 protein possesses E3 ubiquitin ligase activity that is dependent on an intact U-box domain, suggesting a role of the ubiquitination system in the control of plant cell death and defense.

Cytokinesis in many eukaryotes depends on the function of an actomyosin contractile ring. The mechanisms regulating assembly and positioning of this ring are not fully understood. The fission yeast Schizosaccharomyces pombe divides using an actomyosin ring and is an attractive organism for the study of cytokinesis. Recent studies in S. pombe (Wu, J.Q., V. Sirotkin, D.R. Kovar, M. Lord, C.C. Beltzner, J.R. Kuhn, and T.D. Pollard. 2006. J. Cell Biol. 174:391–402; Vavylonis, D., J.Q. Wu, S. Hao, B. O'Shaughnessy, and T.D. Pollard. 2008. Science. 319:97–100) have suggested that the assembly of the actomyosin ring is initiated from a series of cortical nodes containing several components of this ring. These studies have proposed that actomyosin interactions bring together the cortical nodes to form a compacted ring structure. In this study, we test this model in cells that are unable to assemble cortical nodes. Although the cortical nodes play a role in the timing of ring assembly, we find that they are dispensable for the assembly of orthogonal actomyosin rings. Thus, a mechanism that is independent of cortical nodes is sufficient for the assembly of normal actomyosin rings.

Background: The COVID-19 pandemic poses a major threat to global public health and economic development. Moreover, it has put considerable psychological pressure on nurses, who have played a vital role in the prevention and control of the epidemic. Objective: This qualitative study aimed at exploring the experiences and psychological adjustments of nurses who voluntarily traveled to Hubei Province in China to provide support during the COVID-19 epidemic. Methods: We conducted semi-structured, face-to-face interviews with twelve nurses recruited from three hospitals in Jiangsu Province and performed qualitative content analysis of the interview data. Results: The following themes emerged from the analysis: (1) motivations for supporting the hardest-hit areas (professional commitment, family support, and media propaganda); (2) challenges faced during the support missions (heavy workloads, changes in working patterns, communication barriers, and barriers associated with wearing personal protective equipment); (3) psychological experiences (a sense of uncertainty, fear of infection, loneliness, stressful events, and sleep disorders); (4) psychological adjustments (adequate training and personal protective equipment, positive responses to stress, and social support); and (5) personal and professional growth (a strong professional identity, a positive work attitude, a perception of expanded possibilities, realization of the value of learning, and cherishing life). Conclusions and Recommendations: Policy makers and nursing managers should implement effective measures for supporting nurses. They include ensuring adequate workforce preparedness for nurses, strengthening protection training, including professional psychologists in support teams, encouraging nurses to apply self-regulation methods, such as exercising and listening to music, and seeking social support to promote mental health.

Complete cellulose synthesis is required to form functional cell walls and to facilitate proper cell expansion during plant growth. AtCESA2 is a member of the cellulose synthase A family in Arabidopsis (Arabidopsis thaliana) that participates in cell wall formation. By analysis of transgenic seedlings, we demonstrated that AtCESA2 was expressed in all organs, except root hairs. The atcesa2 mutant was devoid of AtCESA2 expression, leading to the stunted growth of hypocotyls in seedlings and greatly reduced seed production in mature plants. These observations were attributed to alterations in cell size as a result of reduced cellulose synthesis in the mutant. The orientation of microtubules was also altered in the atcesa2 mutant, which was clearly observed in hypocotyls and petioles. Complementary expression of AtCESA2 in atcesa2 could rescue the mutant phenotypes. Together, we conclude that disruption of cellulose synthesis results in altered orientation of microtubules and eventually leads to abnormal plant growth. We also demonstrated that the zinc finger-like domain of AtCESA2 could homodimerize, possibly contributing to rosette assemblies of cellulose synthase A within plasma membranes.

Cytokinesis in all organisms involves the creation of membranous barriers that demarcate individual daughter cells. In fission yeast, a signaling module termed the septation initiation network (SIN) plays an essential role in the assembly of new membranes and cell wall during cytokinesis. In this study, we have characterized Slk1p, a protein-kinase related to the SIN component Sid2p. Slk1p is expressed specifically during meiosis and localizes to the spindle pole bodies (SPBs) during meiosis I and II in a SIN-dependent manner. Slk1p also localizes to the forespore membrane during sporulation. Cells lacking Slk1p display defects associated with sporulation, leading frequently to the formation of asci with smaller and/or fewer spores. The ability of slk1⌬ cells to sporulate, albeit inefficiently, is fully abolished upon compromise of function of Sid2p, suggesting that Slk1p and Sid2p play overlapping roles in sporulation. Interestingly, increased expression of the syntaxin Psy1p rescues the sporulation defect of sid2-250 slk1⌬. Thus, it is likely that Slk1p and Sid2p play a role in forespore membrane assembly by facilitating recruitment of components of the secretory apparatus, such as Psy1p, to allow membrane expansion. These studies thereby provide a novel link between the SIN and vesicle trafficking during cytokinesis. INTRODUCTIONCytokinesis in all organisms requires the formation of new membranes between segregated chromosomes, leading eventually to the formation of independent daughter cells (Guertin et al., 2002;Wu et al., 2003;Glotzer, 2001Glotzer, , 2005. In animal cells, assembly of new membranes occurs in coordination with constriction of the actin and myosin containing contractile ring and proceeds in a centripetal direction Gromley et al., 2005;Matheson et al., 2005;Baluska et al., 2006). In plant cells, new membrane growth occurs in a centrifugal manner, and this centrifugal expansion is mediated by targeted vesicle delivery to the spindle midzone (Jurgens, 2005;Baluska et al., 2006). Fungi appear to use two distinct mechanisms depending on the mode of cell cycle regulation. During vegetative growth, as in the case of animal cells, new membrane assembly occurs concomitant with constriction of an actomyosin ring Wu and Pollard, 2005;Wu et al., 2006). In contrast, during meiosis and sporulation, new membrane assembly is initiated around the spindle pole bodies, in an apparently actomyosin ring-independent manner (Shimoda, 2004;Neiman, 2005). Although different cell types use different modes of cytokinesis, elements important for membrane targeting and vesicle fusion are highly conserved. How these conserved molecules participating in membrane biogenesis respond to different signals remains largely unanswered.In recent years, the fission yeast Schizosaccharomyces pombe has become particularly attractive for the study of cytokinesis, due to the ease with which genetic and cell biological analysis are applied in this organism (Gould and Simanis, 1997;McCollum and Gould, 2001;Wu and Pollard, 2005;Wu et al....

SummaryIn plant tissue culture, developmental disturbance and mutagenic factors are involved in channeling an individual totipotent cell to an intact plant. Comparing a pair of sorghum reciprocal F 1 hybrids with their parental pure lines revealed a dramatic difference in the occurrence of both genetic and DNA methylation alterations in the respective regenerated plants. In contrast to those of the pure lines, regenerated plants of hybrids exhibit significantly enhanced genetic and epigenetic stability. The genetic changes detected by amplified fragment length polymorphism and the DNA methylation alterations detected by methylationsensitive amplified polymorphism are intimately correlated with each other, suggesting a common mechanism underlying both kinds of instabilities. Markedly altered transcription of genes encoding four putative sorghum DNA methyltransferases and two 5-methylcytosine glycosylases with nucleotide sequences orthologous to Arabidopsis counterparts was induced by tissue culture. The steady-state transcript levels of these genes were negatively correlated with genetic and methylation alterations. A salient observation is that tissue culture-induced transcription of genes encoding DNA methyltransferases and 5-methylcytosine glycosylases in calli and/or regenerated plants of the hybrids was remarkably coordinated, but is largely uncoordinated and stochastically altered in calli and/or regenerated plants of the pure lines. We suggest that the uncoordinated regulation of expression of DNA methyltransferases and 5-methylcytosine glycosylases is a major cause of the high incidence of genetic and DNA methylation alterations in cultures of pure lines, but coordinated up-regulated expression of these enzymes in cultures of the F 1 hybrids fortified their genetic and epigenetic stability.

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The objective of this study was to evaluate inter-rater reliability of Braden Scale, Norton Scale and Waterlow Scale for pressure ulcer risk assessment in clinical practice. The design of the study was cross-sectional. A total of 23 patients at pressure ulcer risk were included in the study, and 6 best registered nurses conducted three subsequent risk assessments for all included patients. They assessed alone and independently from each other. An intra-class correlation coefficient (ICC) was used to determine the inter-rater reliability. For the Braden Scale, the ICC values ranged between 0·603 (95% CI: 0·435-0·770) for the item 'moisture' and a maximum of 0·964 (95% CI: 0·936-0·982) for the item 'activity'; for the Norton Scale, the ICC values ranged between 0·595 (95% CI: 0·426-0·764) for the item 'physical condition' and a maximum of 0·975 (95% CI: 0·955-0·988) for the item 'activity'; and for the Waterlow Scale, the ICC values ranged between 0·592 (95% CI: 0·422-0·762) for the item 'skin type' and a maximum of 0·990 (95% CI: 0·982-0·995) for the item 'activity'. The ICC values of total score for three scales of were 0·955 (95% CI: 0·922-0·978), 0·967 (95% CI: 0·943-0·984), and 0·915 (95% CI: 0·855-0·958) for Braden, Norton, and Waterlow scales, respectively. Although the inter-rater reliability of Braden Scale, Norton Scale and Waterlow Scale total scores were all substantial, the reliability of some items was not so good. The items of 'moisture', 'physical condition' and 'skin type' should be paid more attention. However, some studies are needed to find out high reliable quantitative items to replace these ambiguous items in new designed scales.