Rice GA3ox1 modulates pollen starch granule accumulation and pollen wall development.

The rice GA biosynthetic gene OsGA3ox1 has been proposed to regulate pollen development through the gametophytic manner, but cellular characterization of its mutant pollen is lacking. In this study, three heterozygotic biallelic variants, "-3/-19", "-3/-2" and "-3/-10", each containing one null and one 3bp-deletion allele, were obtained by the CRISPR/Cas9 technique for the functional study of OsGA3ox1. The three homozygotes, "-19/-19", "-2/-2" and "-10/-10", derived from heterozygotic variants, did not affect the development of most vegetative and floral organs but showed a significant reduction in seed-setting rate and in pollen viability. Anatomic characterizations of these mutated osga3ox1 pollens revealed defects in starch granule accumulation and pollen wall development. Additional molecular characterization suggests that abnormal pollen development in the osga3ox1 mutants might be linked to the regulation of transcription factors OsGAMYB, OsTDR and OsbHLH142 during late pollen development. In brief, the rice GA3ox1 is a crucial gene that modulates pollen starch granule accumulation and pollen wall development at the gametophytic phase.

Comparisons within the Rice GA 2-Oxidase Gene Family Revealed Three Dominant Paralogs and a Functional Attenuated Gene that Led to the Identification of Four Amino Acid Variants Associated with GA Deactivation Capability.

BACKGROUND: GA 2-oxidases (GA2oxs) are involved in regulating GA homeostasis in plants by inactivating bioactive GAs through 2ß-hydroxylation. Rice GA2oxs are encoded by a family of 10 genes; some of them have been characterized, but no comprehensive comparisons for all these genes have been conducted. RESULTS: Rice plants with nine functional GA2oxs were demonstrated in the present study, and these genes not only were differentially expressed but also revealed various capabilities for GA deactivation based on their height-reducing effects in transgenic plants. Compared to that of wild-type plants, the relative plant height (RPH) of transgenic plants was scored to estimate their reducing effects, and 8.3% to 59.5% RPH was observed. Phylogenetic analysis of class I GA2ox genes revealed two functionally distinct clades in the Poaceae. The OsGA2ox3, 4, and 8 genes belonging to clade A showed the most severe effect (8.3% to 8.7% RPH) on plant height reduction, whereas the OsGA2ox7 gene belonging to clade B showed the least severe effect (59.5% RPH). The clade A OsGA2ox3 gene contained two conserved C186/C194 amino acids that were crucial for enzymatic activity. In the present study, these amino acids were replaced with OsGA2ox7-conserved arginine (C186R) and proline (C194P), respectively, or simultaneously (C186R/C194P) to demonstrate their importance in planta. Another two amino acids, Q220 and Y274, conserved in OsGA2ox3 were substituted with glutamic acid (E) and phenylalanine (F), respectively, or simultaneously to show their significance in planta. In addition, through sequence divergence, RNA expression profile and GA deactivation capability analyses, we proposed that OsGA2ox1, OsGA2ox3 and OsGA2ox6 function as the predominant paralogs in each of their respective classes. CONCLUSIONS: This study demonstrates rice has nine functional GA2oxs and the class I GA2ox genes are divided into two functionally distinct clades. Among them, the OsGA2ox7 of clade B is a functional attenuated gene and the OsGA2ox1, OsGA2ox3 and OsGA2ox6 are the three predominant paralogs in the family.

Decision-Making in People With Dementia or Mild Cognitive Impairment: A Narrative Review of Decision-Making Tools.

OBJECTIVES: This review summarized the applicability of various decision-making tools for helping people with dementia or mild cognitive impairment (MCI) and their families make decisions. DESIGN: This study was a narrative literature review. The protocol of this review was registered in the International Prospective Register of Systematic Reviews (PROSPERO ID: CRD42020182259). SETTING AND PARTICIPANTS: People with dementia or MCI and their families were included in this study. METHODS: This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We searched the Cochrane Library, PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and Chinese Electronic Periodical Services databases from inception to May 2021. The Joanna Briggs Institute Critical Appraisal Checklists for a variety of study designs were used. RESULTS: Topics related to decision-making were categorized as everyday activity decisions or medical treatment decisions. Various types of decision-making tools were identified, and we observed that decision aids can be modified and used for both everyday activity decisions and medical treatment decisions. In addition to highlighting decision aids for specific decisional issues and topics, we also elucidated other validated tools that can be used to facilitate the decision-making process. CONCLUSIONS AND IMPLICATIONS: This study highlighted the topics involved in decision-making and using decision-making tools. The current review provides information that can help individuals and health care professionals choose optimal decision-making tools. On the basis of our findings, future studies can determine the most appropriate tools for intervention or outcome measures.

Phalaenopsis orchid miniaturization by overexpression of OsGA2ox6, a rice GA2-oxidase gene.

BACKGROUND: Phalaenopsis orchids are one of the most common potted orchids sold worldwide. Most Phalaenopsis cultivars have long inflorescences that cause shipping problems and increase handling costs. Miniaturization of Phalaenopsis orchids not only reduces overall production costs but also can expand the appeal of the orchids to a different group of consumers who prefer to keep flowers on desks or tabletops. Although some miniature Phalaenopsis plants can be obtained via hybridization or mutation, they are unpredictable and limited in variety. We therefore used the transgenic approach of overexpressing gibberellin 2-oxidase 6 (OsGA2ox6), a rice GA deactivation gene, to investigate its functional effect in miniaturizing Phalaenopsis and to create a stable miniaturization platform to facilitate a supply for the potential demands of the miniature flower market. RESULTS: A commercial moth orchid, Phalaenopsis Sogo Yukidian 'SPM313', was transformed with the plasmid vector Ubi:OsGA2ox6 and successfully overexpressed the OsGA2ox6 gene in planta. The transgenic lines displayed darker-green, shorter, and wider leaves, thicker roots and much shorter flower spikes (10 cm vs 33 cm) than the nontransgenic line with a normal flower size and blooming ability and are therefore an ideal miniaturized form of Phalaenopsis orchids. CONCLUSIONS: We demonstrated that the ectopic expression of OsGA2ox6 can miniaturize Phalaenopsis Sogo Yukidian 'SPM313' while preserving its blooming ability, providing an alternative, useful method for miniaturizing Phalaenopsis species. This miniaturization by a transgenic approach can be further expanded by using GA2ox genes from different plant species or different gene variants, thereby expanding the technical platform for miniaturizing Phalaenopsis species to meet the potential demands of the miniature Phalaenopsis flower market.

A Novel Role for Pyruvate Kinase M2 as a Corepressor for P53 during the DNA Damage Response in Human Tumor Cells.

The pyruvate kinase (PK) is a rate-limiting glycolytic enzyme catalyzing the dephosphorylation of phosphoenolpyruvate to pyruvate, yielding one molecule of ATP. The M2 isoform of PK (PKM2) is predominantly expressed in normal proliferating cells and tumors, and both metabolic and non-metabolic activities for the enzyme in promoting tumor cell proliferation have been identified. However, the exact roles of PKM2 in tumor initiation, growth and maintenance are not yet fully understood. Using immunoprecipitation-coupled LC-MS/MS in MCF7 cells exposed to DNA-damaging agent, we report that the nuclear PKM2 interacts directly with P53 protein, a critical safeguard for genome stability. Specifically, PKM2 inhibits P53-dependent transactivation of the P21 gene by preventing P53 binding to the P21 promoter, leading to a nonstop G1 phase. As a result, PKM2 expression provides a growth advantage for tumor cells in the presence of a DNA damage stimulus. In addition, PKM2 interferes with phosphorylation of P53 at serine 15, known to stimulate P53 activity by the ATM serine/threonine kinase. These findings reveal a new role for PKM2 in modulating the DNA damage response and illustrate a novel mechanism of PKM2 participating in tumorigenesis.

[Effects of grafting on root polyamine metabolism of cucumber seedlings under copper stress].

By the method of hydroponic culture, and taking Cucurbita ficifolia B. as rootstock, this paper studied the effects of grafting on the root polyamine metabolism of cucumber seedlings under copper stress. The results showed that under copper stress, the root activities of cucumber seedlings were inhibited, and electrolyte leakage increased, with these changes being significantly lower for grafted than for ungrafted cucumber seedlings. In addition, the contents of free spermidine and spermine, and of conjugated and bound polyamines were significantly higher in grafted than in ungrafted seedling roots, while the free putrescine content and the ratio of free putrescine to polyamines were on the contrary. Comparing with those in ungrafted cucumber seedlings, the root arginine decarboxylase (ADC), ornithine decarboxylase (ODC), and S-adenosylmethionine decarboxylase (SAMDC) activities in grafted cucumber seedlings were higher, while the diamine oxidase and polyamine oxidase activities were significantly lower. All of these indicated that under copper stress, the synthesis of polyamine in grafted seedling roots was increased, while the degradation of polyamine was decreased, resulting in a higher accumulation of polyamine in the roots, and the increase of the tolerance of cucumber seedlings to copper stress.

[Effects of grafting on cucumber rhizospheric soil microbial characteristics and enzyme activities under copper stress].

A pot experiment with cucumber (taking Cucurbita ficifoblia B. as the rootstock) was conducted to study the effects of grafting on the microbial population, microbial biomass, and enzyme activities in rhizospheric soil under copper stress. Under the stress of copper, the microbial biomass C and N in grafted and self-rooted cucumber rhizospheric soils all decreased significantly, while the basal respiration and metabolic quotient were in adverse. In grafted cucumber rhizospheric soil, the microbial biomass C and N were significantly higher than those in self-rooted cucumber rhiaospheric soil, whereas the basal respiration and metabolic quotient were significantly lower. Under copper stress, the quantities of actinomyces and nitrogen-fixing bacteria in rhizospheric soils decreased and that of fungi increased significantly, whereas the quantity of bacteria had less change. In grafted cucumber rhizospheric soil, the quantities of bacteria, actinomyces, and nitrogen-fixing bacteria were significantly higher than those in self-rooted cucumber rhizospheric soil, but the quantity of fungi was in opposite. The urease, phosphatase, sucrase, and catalase activities were significantly higher in grafted than in self-rooted cucumber rhizospheric soil. All the results suggested that grafting could mitigate the impact of copper stress on the microbial micro-environment and enzyme activities in cucumber rhizospheric soil, and as a result, improve the adaptability of cucumber to copper stress.

[Microflora on mucosa under different pontics of fixed partial bridge].

OBJECTIVE: To investigate the influence of three pontic types on alveolar ridge mucosal microecosystem. METHODS: Sixty patients ready to accept three unit metal ceramic bridges were selected. The bacterial type and the cultivable flora were counted and the proportions of bacteria detected on the top of alveolar ridge mucosal contact area before tooth preparation and three months after bridge insertion. RESULTS: Type and CFU of bacteria on the alveolar ridge mucosa under modified base-type pontics and modified ridge lap pontics increased significantly (P < 0.05); while there was no significant change under the ovata pontics (P > 0.05). Before tooth preparation and 3 months after fixed prosthesis insertion, the percentages of oral Streptococci and Neisseriae changed significantly (P < 0.05). CONCLUSIONS: The ovata pontic had less influence on mucosal microecosystem than the other two pontics and is the appropriate pontic design for clinical dentist.