A pot experiment was conducted to study the dynamic changes of soil enzyme activities and microbial biomass in rhizosphere using two-year-old Hanfu apple.The results showed that: In different soils,microbial biomass C,N,urcase activities and catalase indicated a tendency of loam soilclaysandy soil in total;Phosphatase activities indicated a tendency of clayloamsandy soil.In different developmental stages,microbial biomass C was the lowest in fast growing phase of shoots,and the highest in defoliation phase;microbial biomass N was the lowest in germinating phase,and the highest in withholding growing phase of spring shoots;urcase was the highest in fast growing phase of shoots,phosphatase and catalase were the highest in defoliation phase.The correlation between microbial biomass and enzyme activities was high.The regression equations between microbial biomass and soil enzyme activities were obtained by using a stepwise regression method.The principal component analysis reflected that the microbial biomass N and urcase have higher coefficient in every major constituent,so the two properties can be considered to be the most important soil biological factors in the cool and cold regions.
Bone marrow-derived stem cells (BMDSC) have been implicated in tumor formation, though it is not clear whether they contribute to tumor growth. A novel mobilizer of BMDSC (StemEnhance; SE) was used to investigate whether its daily administration promotes tumor growth. Forty mice were surgically transplanted with human MDA-MB-435-GFP breast cancer into the mammary fat pad of nude mice, The mice were gavaged for six weeks with 300 mg/kg of SE. Tumor growth was monitored using live whole-body fluorescence imaging. At the end of the study, tumors were excised and weighed. At the start of the feeding trial, tumor areas for both control and experimental group were statistically identical. Tumor growth rate was slower in the SE group (p = 0.014) when compared to the control group. After 6 weeks, tumor areas were 40% larger in the control p < 0.01) and mean tumor weight was 35% smaller in the SE-treated group (0.44 g vs. 0.68 g; p = 0.031). Feeding of SE did not promote tumor growth but rather reduced the growth of human MDA-MB-435 breast cancer.
Bone marrow-derived stem cells have the ability to migrate to sites of tissue damage and participate in tissue regeneration. The number of circulating stem cells has been shown to be a key parameter in this process. Therefore, stimulating the mobilization of bone marrow stem cells may accelerate tissue regeneration in various animal models of injury. In this study we investigated the effect of the bone marrow stem cells mobilizer StemEnhance (SE), a water-soluble extract of the cyanophyta Aphanizomenon flos-aquae (AFA), on hematopoietic recovery after myeloablation as well as recovery from cardiotoxin-induced injury of the anterior tibialis muscle in mice. Control and SE-treated female mice were irradiated, and then transplanted with GFP+ bone marrow stem cells and allowed to recover. Immediately after transplant, animals were gavaged daily with 300 mg/kg of SE in PBS or a PBS control. After hematopoietic recovery (23 days), mice were injected with cardiotoxin in the anterior tibialis muscle. Five weeks later, the anterior tibialis muscles were analyzed for incorporation of GFP+ bone marrow-derived cells using fluorescence imaging. SE significantly enhanced recovery from cardiotoxin-injury. However, StemEnhance did not affect the growth of the animal and did not affect hematopoietic recovery after myeloablation, when compared to control. This study suggests that inducing mobilization of stem cells from the bone marrow is a strategy for muscle regeneration.
The effects of calcium on respiratory and nitrogen metabolism of apple roots (Malus baccata Borkh.)exposed to temperature stress (5°C ~ 20°C ~ 0°C) were investigated.Seedlings were treated with distilled water (control), calcium chloride (CaCl2) or calmodulin antagonist trifluoperazine (TFP) before temperature stress.Temperature was increased from 5°C to 20°C (1°C h -1 ) and then decreased to 0°C (1°C h -1 ).Temperature stress decreased root vitality and increased root malondialdehyde (MDA) concentration, the effect of which was exacerbated by TFP treatment.Treatment with CaCl2 improved root vitality and decreased root MDA concentration.At 20°C, exogenous CaCl2 alleviated the negative effects of temperature stress on the total respiration rate by enhancing the activity of tricarboxylic acid cycle (TCA).Activities of key enzyme in nitrogen metabolism were strongly inhibited by temperature stress.Exogenous CaCl2 significantly increased key enzyme activities of nitrogen metabolism compared to the control.However, the TFP treatment markedly reduced the activity of glutamate synthase (GOGAT) at 20°C and noticeably inhibited glutamate dehydrogenase (GDH) activity during the entire temperature stress period.The data showed that the Ca 2+ -calmodulin (Ca 2+ -CaM) signal system was involved in increase of GOGAT and GDH activity that occurred with an increase in temperature, and played a role in the increase in the total respiration rate and GDH activity which occurred with a decrease in temperature.Cultural practices that improve plant calcium (Ca) status in the early spring may mitigate damage induced by temperature stress.
An in vitro shoot regeneration technique combined with colchicine application has been employed to produce hexaploid plants from leaf segments of the triploid cherry rootstock'Gisela 6'(Prunus ceransus ×P.canescens).Leaf segments were treated firstly with colchicine(0-200 mg·L-1) in the liquid modified WPM medium supplemented with auxin(IBA 0.5 mg·L-1) and cytokinin(BA 5.0 mg·L-1) for five days and then transferred on the same regeneration solid medium with no colchicine for 56 days.In this case,putative hexaploid shoots were only regenerated from the leaf explants in the treatment of 50 mg·L-1 colchicine after 8 weeks on the regeneration medium.Flow cytometry was used for ploidy determination.The hexaploid plants were distinguishable from the triploid on morphological characters.All plants were successfully transplanted into field and topworked on the sweet cherry trees to evaluate its agronomic traits.
Background: Hanfu apples have the advantages of cold resistance, drought resistance, and high yield, and they have become the main variety grown in the cool areas of Northeast, Northwest, and North China (40–42° N), which have an average temperature of -12 to -10 ℃ in January. Results: Here, we proposed a chromosome-level Hanfu genome assembly using PacBio long reads, Illumina short reads, 10× Genomics linked reads, and Hi-C data. The total contig length was 628.99 Mb, and the N50 contig length was 1.25 Mb. The total scaffold length was 631.76 Mb, the N50 scaffold length was 36.18 Mb, and the genome mount rate was 99.18%. The Hanfu genome had a total of 39 617 genes, and we predicted the function for 38 816 (98.0%) of these. Repetitive sequences accounted for 54.29% of the genome. Evolutionary analysis showed that the differentiation time of apples and pears was approximately 8.9 Mya. Whole genome duplication (WGD) analysis revealed a γ event in Hanfu, which was a recent whole genome duplication when the 4dTv value was 0.075. By comparing and analyzing the genomic differences between Hanfu and the homozygous line HFTH1, three variation types were determined: single-nucleotide polymorphisms (SNPs), insertions/deletions (indels), and structural variants (SVs). We identified 605 species-specific gene families. Among these, 122 Hanfu gene families (including 814 genes) significantly expanded, while 421 gene families significantly contracted (including 1528 genes), and there are 61 candidate genes subject to positive selection. A significant expansion of genes involved in the MAPK signal transduction pathway, calcium-mediated signal transduction pathway, plant hormone signal transduction pathway, sugar metabolism pathway, and phloem development were found; this may explain the formation of ‘Hanfu’s’ unique phenotype. Conclusions: This high quality genome will help explain the formation mechanism of the unique phenotype of Hanfu. In addition, it can provide reference for the genetic improvement of apples and for breeding more varieties with high resistance and high quality.
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