FANCM interacts with the MHF1-MHF2 complex to limit crossover frequency during rice meiosis.

Crossovers (COs) are necessary for generating genetic diversity that breeders can select, but there are conserved mechanisms that regulate their frequency and distribution. Increasing CO frequency may raise the efficiency of selection by increasing the chance of integrating more desirable traits. In this study, we characterize rice FANCM and explore its functions in meiotic CO control. FANCM mutations do not affect fertility in rice, but they cause a great boost in the overall frequency of COs in both inbred and hybrid rice, according to genetic analysis of the complete set of fancm zmm (hei10, ptd, shoc1, mer3, zip4, msh4, msh5, and heip1) mutants. Although the early homologous recombination events proceed normally in fancm, the meiotic extra COs are not marked with HEI10 and require MUS81 resolvase for resolution. FANCM depends on PAIR1, COM1, DMC1, and HUS1 to perform its functions. Simultaneous disruption of FANCM and MEICA1 synergistically increases CO frequency, but it is accompanied by nonhomologous chromosome associations and fragmentations. FANCM interacts with the MHF complex, and ablation of rice MHF1 or MHF2 could restore the formation of 12 bivalents in the absence of the ZMM gene ZIP4. Our data indicate that unleashing meiotic COs by mutating any member of the FANCM-MHF complex could be an effective procedure to accelerate the efficiency of rice breeding.

Transcriptomic and physiological analysis provide new insight into seed shattering mechanism in Pennisetum alopecuroides 'Liqiu'.

KEY MESSAGE: Through the histological, physiological, and transcriptome-level identification of the abscission zone of Pennisetum alopecuroides 'Liqiu', we explored the structure and the genes related to seed shattering, ultimately revealing the regulatory network of seed shattering in P. alopecuroides. Pennisetum alopecuroides is one of the most representative ornamental grass species of Pennisetum genus. It has unique inflorescence, elegant appearance, and strong stress tolerance. However, the shattering of seeds not only reduces the ornamental effect, but also hinders the seed production. In order to understand the potential mechanisms of seed shattering in P. alopecuroides, we conducted morphological, histological, physiological, and transcriptomic analyses on P. alopecuroides cv. 'Liqiu'. According to histological findings, the seed shattering of 'Liqiu' was determined by the abscission zone at the base of the pedicel. Correlation analysis showed that seed shattering was significantly correlated with cellulase, lignin, auxin, gibberellin, cytokinin and jasmonic acid. Through a combination of histological and physiological analyses, we observed the accumulation of cellulase and lignin during 'Liqiu' seed abscission. We used PacBio full-length transcriptome sequencing (SMRT) combined with next-generation sequencing (NGS) transcriptome technology to improve the transcriptome data of 'Liqiu'. Transcriptomics further identified many differential genes involved in cellulase, lignin and plant hormone-related pathways. This study will provide new insights into the research on the shattering mechanism of P. alopecuroides.

RAD51C-RAD51D interplays with MSH5 and regulates crossover maturation in rice meiosis.

Meiotic crossovers ensure accurate chromosome segregation and increase genetic diversity. RAD51C and RAD51D play an early role in facilitating RAD51 during homologous recombination. However, their later function in meiosis is largely unknown in plants. Here, through targeted disruption of RAD51C and RAD51D, we generated three new mutants and revealed their later meiotic role in crossover maturation. The rad51c-3 and rad51d-4 mutants showed a mixture of bivalents and univalents and no chromosomal entanglements, whereas rad51d-5 exhibited an intermediate phenotype with reduced chromosomal entanglements and increased bivalent formation compared with knockout alleles. Comparisons of RAD51 loadings and chromosomal entanglements in these single mutants, rad51c-3 rad51d-4, rad51c-3 dmc1a dmc1b, and rad51d-4 dmc1a dmc1b suggest that the retained level of RAD51 in mutants is required for uncovering their function in crossover formation. Reductions in chiasma frequency and later HEI10 foci in these mutants support that crossover maturation requires RAD51C and RAD51D. Moreover, interaction between RAD51D and MSH5 indicates that RAD51 paralogs may cooperate with MSH5 to ensure accurate Holliday junction processing into crossover products. This finding of the role of RAD51 paralogs in crossover control may be conserved from mammals to plants and advances our current understanding of these proteins.

MUS81 is required for atypical recombination intermediate resolution but not crossover designation in rice.

The endonuclease methyl methanesulfonate and UV-sensitive protein 81 (MUS81) has been reported to participate in DNA repair during mitosis and meiosis. However, the exact meiotic function of MUS81 in rice remains unclear. Here, we use a combination of physiological, cytological, and genetic approaches to provide evidence that MUS81 functions in atypical recombination intermediate resolution rather than crossover designation in rice. Cytological and genetic analysis revealed that the total chiasma numbers in mus81 mutants were indistinguishable from wild-type. The numbers of HEI10 foci (the sites of interference-sensitive crossovers) in mus81 were also similar to that of wild-type. Moreover, disruption of MUS81 in msh5 or msh4 msh5 background did not further decrease chiasmata frequency, suggesting that rice MUS81 did not function in crossover designation. Mutation of FANCM and ZEP1 could enhance recombination frequency. Unexpectedly, chromosome fragments and bridges were frequently observed in mus81 zep1 and mus81 fancm, illustrating that MUS81 may resolve atypical recombination intermediates. Taken together, our data suggest that MUS81 contributes little to crossover designation but plays a crucial role in the resolution of atypical meiotic intermediates by working together with other anti-crossover factors.

Is the happiness of Chinese truly the highest in the world? The impact of basic public services on happiness.

Based on the survey report by the United Nations Sustainable Development Solutions Network (SDSN) and Ipsos Group, the world ranking of Chinese people's happiness shows a significant gap. This study attempts to analyze the subjective well-being of Chinese residents through public database from the China Household Finance Survey Center in 2017. An ordered Probit model is constructed to investigate the impact of non-monetary factors, specifically basic public services, on the subjective well-being of Chinese people. The results indicate that: (1) The subjective well-being of Chinese residents is found to be lower than what the survey report indicated. (2) Basic public services have a significant positive impact on residents' happiness. (3) Social trust played a moderating role, positively influencing the relationship between basic public services and residents' happiness. (4) The impact of basic public services on happiness varied significantly depending on factors such as age, registered residence, and places of residence. To enhance the happiness of Chinese residents, it is recommended to focus on improving the equalization of basic public services and establishing a robust basic public service system. These measures can effectively contribute to the overall well-being and happiness of the population.

A green method for decolorization of polysaccharides from alfalfa by S-8 macroporous resin and their characterization and antioxidant activity.

In this study, the decolorization conditions of polysaccharides extracted from alfalfa by S-8 macroporous adsorption resin were optimized through the response surface method, and the physicochemical properties and antioxidant activity of decolorized polysaccharides were investigated. The optimal decolorization conditions were determined to be as follows: the amount of S-8 macroporous adsorption resin was 1.4 g, the adsorption time was 2 h, and the adsorption temperature was 58 °C. Under these optimal conditions, a decolorization ratio of 71.43 ± 0.23% was achieved, which was consistent with the model hypothesis. The adsorption curve showed that S-8 macroporous adsorption resin adsorption of pigment molecules in alfalfa polysaccharides (APS) agreed with the Freundlich and pseudo-second-order equations, and the adsorption was a spontaneous endothermic process. High-performance liquid chromatography (HPLC) analysis of monosaccharide composition showed that APS was composed of mannose, glucose, galactose, arabinose and glucuronic acid in a molar ratio of 1.18 : 8.04 : 1.22 : 0.92 : 1. The results of antioxidant activity studies showed that APS had strong scavenging activity against ABTS, DPPH and hydroxyl radicals. This study will help to further understand the adsorption mechanism of macroporous resin on polysaccharide pigment molecules and lay a basis for evaluating their physiological activity.

Ultrasound-controlled MXene-based Schottky heterojunction improves anti-infection and osteogenesis properties.

Background: The current clinical treatment of osteomyelitis is limited by the emergence of drug-resistant bacteria, which often leads to the failure of traditional antibiotic treatment and large bone defects. Sonodynamic therapy (SDT) is a new strategy that is widely used to overcome the problem of bacterial resistance to antibiotic therapy as well as poor tissue penetration using near-infrared light in photodynamic therapy (PDT). Therefore, it is necessary to develop a new sonosensitizer that can kill bacteria and promote bone repair. Methods: Herein, we developed a sonosensitizer, porphyrin metal-organic framework (HNTM), with a Schottky junction modified by Ti3C2 nanosheets (HN-Ti3C2) for highly efficient sonodynamic therapy of osteomyelitis and bone regeneration. Results: Ti3C2 greatly improves the acoustic catalytic performance by rapidly transferring the charge carriers generated by HNTM under ultrasound (US) irradiation, which killing drug-resistant bacteria through the generation of large amounts of reactive oxygen species (ROS). And HN-Ti3C2 shows excellent 99.75% antibacterial effectiveness against MRSA. In addition, HN-Ti3C2 generates a sonocurrent under low-intensity US to promote the repair of bone defects for a long time period. Mechanistic research using CCK-8 and RNA-seq showed that HN-Ti3C2 nanocomposites can promote the proliferation of stem cells by regulating the cell cycle, DNA replication, and apoptosis. In addition, after low-intensity US irradiation, HN-Ti3C2 promotes osteogenic differentiation via some key signaling pathways, including the calcium, Wnt, and TGF-beta signaling pathways, according to the Kyoto Encyclopedia of Genes and Genomes (KEGG). In a MRSA-infected rat tibial osteomyelitis model, HN-Ti3C2 successfully eliminated the infection and significantly improved bone regeneration under US irradiation. Conclusion: This study indicates that engineered HN-Ti3C2 is a distinctive nanocomposite for successful osteomyelitis treatment.

Nitrogen nutrition contributes to plant fertility by affecting meiosis initiation.

Nitrogen (N), one of the most important plant nutrients, plays crucial roles in multiple plant developmental processes. Spikelets are the primary sink tissues during reproductive growth, and N deficiency can cause floral abortion. However, the roles of N nutrition in meiosis, the crucial step in plant sexual reproduction, are poorly understood. Here, we identified an N-dependent meiotic entrance mutant with loss of function of ELECTRON TRANSFER FLAVOPROTEIN SUBUNIT ß (ETFß) in rice (Oryza sativa). etfß displayed meiosis initiation defects, excessive accumulation of branched-chain amino acids (BCAAs) and decrease in total N contents in spikelets under N starvation, which were rescued by applying excess exogenous inorganic N. Under N starvation, ETFß, through its involvement in BCAA catabolism, promotes N reutilization and contributes to meeting N demands of spikelets, highlighting the impact of N nutrition on meiosis initiation. We conclude that N nutrition contributes to plant fertility by affecting meiosis initiation.

The E3 ubiquitin ligase DESYNAPSIS1 regulates synapsis and recombination in rice meiosis.

Synaptonemal complex (SC) assembly and homologous recombination, the most critical events during prophase I, are the prerequisite for faithful meiotic chromosome segregation. However, the underlying regulatory mechanism remains largely unknown. Here, we reveal that a functional RING finger E3 ubiquitin ligase, DESYNAPSIS1 (DSNP1), plays significant roles in SC assembly and homologous recombination during rice meiosis. In the dsnp1 mutant, homologous synapsis is discontinuous and aberrant SC-like polycomplexes occur independent of coaligned homologous chromosomes. Accompanying the decreased foci of HEI10, ZIP4, and MER3 on meiotic chromosomes, the number of crossovers (COs) decreases dramatically in dsnp1 meiocytes. Furthermore, the absence of central elements largely restores the localization of non-ZEP1 ZMM proteins and the number of COs in the dsnp1 background. Collectively, DSNP1 stabilizes the canonical tripartite SC structure along paired homologous chromosomes and further promotes the formation of COs.

[Significance of Neutrophil/Lymphocyte Ratio and Platelet/Lymphocyte Ratio in Patients with Multiple Myeloma].

OBJECTIVE: To investigate the significance of neutrophil/lymphocyte ratio(NLR) and platelet/lymphocyte ratio(PLR) in patients with multiple myeloma (MM). METHODS: Eighty patients with multiple myeloma admitted in our hospital from August 2007 to August 2010 were selected. The clinical data of the patients, including hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red blood cell distribution width (RDW), white blood cell(WBC) count, absolute neutrophil count (ANC), platelet count (PC), glomerular filtration rate (GFR), calcium, albumin, ß2 microglobulin and so on were collected and analyzed. RESULTS: The optimal threshold of NLR was 2.78 (sensitivity: 83.3%, specificity: 43.1%). The optimal threshold of PLR was 155.58 (sensitivity: 67.7%, specificity: 36.9%). All patients were grouped according to NLR and PLR values, patients with high NLR and PLR had lower albumin levels and higher clinical stages. High NLR patients were mainly men, hemoglobin, GFR values, albumin levels were lower, and the white blood cells count and ß2 microglobulin level were higher. High PLR patients showed low albumin level and higher clinical stage. Multivariate analysis showed that ß2 microglobulin and NLR were prognostic factors in patients with multiple myeloma (P<0.05). Kaplan-Meier survival analysis showed that the median survival time was 37 months (95% CI: 21.80-52.19) for patients with high NLR and 66 months (95% CI: 53.19-78.80) for patients with low NLR. The median survival time was 45 months (95% CI: 0.00 to 91.18) in patients with high PLR and 62 months (95% CI: 45.67-78.33) in patients with low PLR. CONCLUSION: High NLR (>2.78) associates with poor prognosis in patients with MM, and it may be considered as an independent prognostic factor for MM patients.

[Expression and Significance of PTEN and BCL-2 in Acute Myeloid Leukemia].

OBJECTIVE: To explore the expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN) and B-cell lymphoma/leukemia-2 (BCL-2) in acute myeloid leukemia (AML) and its significance. METHODS: The expression levels of PTEN and BCL-2 mRNA and protein in bone marrow samples from 80 AML patients including 56 de novo patients, 16 patients in remission, 8 relapsed patients and 30 cases of non-hematologic diseases (as control) were detected by real-time PCR and Western blot, respectively, and the relationship between PTEN and BCL-2 expression and clinical pathological parameter was analyzed. RESULTS: The expression levels of both mRNA and protein of PTEN in newly diagnosed AML group and relapse group were significantly lower than those in the control and remission group (P<0.01). The expression levels of both mRNA and protein of BCL-2 in newly diagnosed group and relapse group were significantly higher than those in the control and remission group (P<0.01). The mRNA expression of PTEN and BCL-2 was did not related with the age, sex and white blood count in AML patients. The expression levels of PTEN negatively correlated with expression BCL-2 with AML(r=-0.432, r=-0.569). CONCLUSION: PTEN and BCL-2 participate in the occurrence and development of AML, and may be used as indicators for the evaluation of chemotheraeutic efficacy.

Two new antifungal saponins from the Tibetan herbal medicine Clematis tangutica.

Bioassay-guided fractionation of the ethanol extract of the aerial parts of Clematis tangutica led to the isolation of two new antifungal triterpene saponins. Their structures were determined to be 3- O-alpha- L-arabinopyranosyl hederagenin 28- O-alpha- L-rhamnopyranosyl ester ( 1) and 3- O-beta- D-glucopyranosyl-(1--> 4)-alpha- L-arabinopyranosyl hederagenin 28- O-alpha- L-rhamnopyranosyl ester ( 2) on the basis of spectral data and chemical evidence. Inhibitory activities of the two saponins against seven fungal strains were evaluated. Compounds 1 and 2 showed evident antifungal activity (MIA approximately 2.5 micrograms/disc) against Saccharomyces cerevisiae, similar to the positive control amphotericin B and ordinary activities (MIA approximately 10 micrograms/disc) against Penicillium avellaneum UC-4376, Candida glabrata, Trichosporon beigelii and Pyricularia oryzae. Compound 2 is a better antifungal agent than compound 1 against most of the fungal strains that were tested.