Cytological and morphology characteristics of natural microsporogenesis within Camellia oleifera

Camellia oleifera is believed to exhibit a complex intraspecific polyploidy phenomenon. Abnormal microsporogenesis can promote the formation of unreduced gametes in plants and lead to sexual polyploidy, so it is hypothesized that improper meiosis probably results in the formation of natural polyploidy in Camellia oleifera. In this study, based on the cytological observation of meiosis in pollen mother cells (PMCs), we found natural 2n pollen for the first time in Camellia oleifera, which may lead to the formation of natural polyploids by sexual polyploidization. Additionally, abnormal cytological behaviour during meiosis, including univalent chromosomes, extraequatorial chromosomes, early segregation, laggard chromosomes, chromosome stickiness, asynchronous meiosis and deviant cytokinesis (monad, dyads, triads), was observed, which could be the cause of 2n pollen formation. Moreover, we confirmed a relationship among the length–width ratio of flower buds, stylet length and microsporogenesis. This result suggested that we can immediately determine the microsporogenesis stages by phenotypic characteristics, which may be applicable to breeding advanced germplasm in Camellia oleifera.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-01002-5.     

Serum Uric Acid and Non-Alcoholic Fatty Liver Disease in Non-Diabetic Chinese Men

Increased serum uric acid (SUA) levels may be involved in the development of non-alcoholic fatty liver disease (NAFLD) in men presenting with metabolic syndrome (MetS) and/or insulin resistance. We aimed to determine the independent relationship between SUA and NAFLD in non-diabetic Chinese male population, and to explore the determinants of SUA levels among indexes of adiposity, lipid, and genotypes pertaining to triglycerides metabolism, inflammation, oxidative stress, and SUA concentrations. A total of 1440 men, classified depending on the presence of ultrasonographically detected NAFLD, underwent a complete healthy checkup program. Genotypes were extracted from our previously established genome-wide association study database. After adjusting for age, smoking, drinking, body mass index, homeostasis model assessment of insulin resistance, C-reactive protein, creatinine, alanine aminotransferase (ALT) and components of metabolic syndrome, the odds ratio for NAFLD, comparing the highest with the lowest SUA quartile, was 2.81 (95% confidence interval 1.66–4.76). A stepwise multivariate linear regression analysis (R² = 0.238, P<0.001) retained age, waist circumference, serum creatinine, triglycerides, the Q141K variant in ABCG2 (rs2231142) and NAFLD as significant predictors of SUA levels (all P<0.001). Besides, ALT and Met196Arg variant in TNFRSF1B (rs1061622) additionally associated with SUA among individuls with NAFLD. Our data suggest that in Chinese men, elevated SUA is significantly associated with NAFLD, independent of insulin resistance and other metabolic disorders, such as central obesity or hypertriglyceridemia. Meanwhile, among subjects with NAFLD, index of liver damage, such as elevated ALT combined with genetic susceptibility to inflammation associated with increased SUA levels.     

Knockdown of ribosomal protein S7 causes developmental abnormalities via p53 dependent and independent pathways in zebrafish

Ribosomal proteins (RPs), structural components of the ribosome involved in protein synthesis, are of significant importance in all organisms. Previous studies have suggested that some RPs may have other functions in addition to assembly of the ribosome. The small ribosomal subunits RPS7, has been reported to modulate the mdm2-p53 interaction. To further investigate the biological functions of RPS7, we used morpholino antisense oligonucleotides (MO) to specifically knockdown RPS7 in zebrafish. In RPS7-deficient embryos, p53 was activated, and its downstream target genes and biological events were induced, including apoptosis and cell cycle arrest. Hematopoiesis was also impaired seriously in RPS7-deficient embryos, which was confirmed by the hemoglobin O-dianisidine staining of blood cells, and the expression of scl, gata1 and α-E1 globin were abnormal. The matrix metalloproteinase (mmp) family genes were also activated in RPS7 morphants, indicating that improper cell migration might also cause development defects. Furthermore, simultaneously knockdown of the p53 protein by co-injecting a p53 MO could partially reverse the abnormal phenotype in the morphants. These results strengthen the hypothesis that specific ribosomal proteins regulate p53 and that their deficiency affects hematopoiesis. Moreover, our data implicate that RPS7 is a regulator of matrix metalloproteinase (mmp) family in zebrafish system. These specific functions of RPS7 may provide helpful clues to study the roles of RPs in human disease.     

Different roles of P1 and P2 Saccharomyces cerevisiae ribosomal stalk proteins revealed by cross-linking

The stalk is an essential domain of the large ribosomal subunit formed by a complex of a set of very acidic proteins bound to a core rRNA binding component. While in prokaryotes there is only one type acidic protein, L7/12, two protein families are found in eukaryotes, phosphoproteins P1 and P2, which presumably have different roles. To search for differences zero-length cross-linking by S-S bridge formation was applied using Saccharomyces cerevisiae mutant P1 and P2 proteins carrying single cysteine residues at various positions. The results show a more exposed location of the N-terminal domain of the P2 proteins, which in contrast to P1, can be found as dimers when the Cys is introduced in this domain. Similarly, the Cys containing C-terminal domain of mutant P2 proteins shows a notable capacity to form cross-links with other proteins, which is considerably lower in the P1 type. On the other hand, mutation at the conserved C-domain of protein P0, the eukaryotic stalk rRNA binding component, results in removal of about 14 terminal amino acids. Protein P2, but not P1, protects mutant P0 from this truncation. These results support a eukaryotic stalk structure in which P1 proteins are internally located with their C-terminals having a restricted reactivity while P2 proteins are more external and accessible to interact with other cellular components.     

Amino acid composition of leaf,grain and bracts of japonica rice (<Emphasis Type="Italic">Oryza Sativa</Emphasis> ssp. <Emphasis Type="Italic">japonica</Emphasis>) and its response to nitrogen fertilization

Heat stress is one of the main abiotic stresses that limit plant growth. The effects of high temperature on oxidative damage, PSII activity and D1 protein turnover were studied in three wheat varieties with different heat susceptibility (CS, YN949 and AK58). The results showed that heat stress induced lower lipid peroxidation in AK58 and YN949 than CS, which was related to different changes of SOD, CAT, POD and H₂O₂. Similarly, AK58 and YN949 performed better PSII photochemical efficiency (F_v/F_m, ΦPSII and ETR) under high temperature, which was attributed to rapid synthesis and degradation of D1 protein. Moreover, higher expression of D1 protein turnover-related genes (PsbA, STN8, PBCP, Deg1, Deg2, Deg5, Deg8, FtsH1/5 and FtsH2/8) and SOD activity in AK58 and YN949 under normal conditions also established a basis for acclimatizing high temperatures, thereby alleviating PSII photoinhibition and reducing oxidative damage when exposed to heat stress.     

川西周公山柳杉人工林群落的边缘效应

为研究人工林群落的边缘效应特征, 本文以川西周公山森林公园的柳杉(Cryptomeria fortunei)人工林破碎化大斑块为对象, 以植株平均胸径、平均高度、平均密度、丰富度指数(D)和Shannon-Wiener指数(H)来综合衡量边缘效应深度。在实地踏查的基础上, 从林缘向林内(梯度1至梯度5)设置5条样带(宽度为10 m), 在每条样带中设置4个10 m × 10 m的小样方进行调查。结果表明: (1)从物种组成上看, 在总面积为2,000 m²的20个小样方中共记录到111个物种, 隶属于54科96属, 物种数从林缘至林内递减。(2)从群落结构上看, 乔木层的平均胸径从林缘至林内呈减小趋势, 平均密度则相反, 平均高度无显著变化; 灌木层的平均密度从林缘向林内减小, 平均高度无显著变化; 草本层的平均密度和平均高度均呈减小趋势。(3)从物种多样性上看, 总体上各层次的丰富度指数和Shannon-Wiener指数均从林缘向林内呈减小趋势, 其中灌木层和草本层的变化趋势最明显; 同时, 林内各梯度与梯度1 (林缘)的共有种和相似性系数从林缘向林内递减。(4)分析各项群落特征发现, 平均高度、平均密度和相似性系数的数值在梯度2向梯度3过渡时的起伏变化最明显, 推断本研究中柳杉人工林斑块的边缘深度可达林内20 m。     

Remediation of chromite ore processing residue by pyrolysis process with sewage sludge

The present work developed a novel technique to treat chromite ore processing residue (COPR). The process involved mixing the COPR with sewage sludge followed by pyrolysis. The gaseous organic fraction generated during pyrolysis of sludge was beneficial to Cr(VI) reduction. Process variables, such as the amount of sludge added to COPR (sludge-to-COPR (S/C) ratio), heating temperature, reaction time and particle size, were systematically varied, and their influences on the Cr(VI) reduction in COPR were investigated. Cr(VI) content had decreased greatly, from 3384 mg kg⁻¹ for untreated COPR to less than 30 mg kg⁻¹ for COPR treated at 600 °C.