Biased mutations and gene losses underlying diploidization of the tetraploid broomcorn millet genome.

Broomcorn millet (Panicum miliaceum L.) is one of the earliest domesticated crops, and is a valuable resource to secure food diversity and combat drought stresses under the global warming scenario. However, due to the absence of extant diploid progenitors, the polyploidy genome of broomcorn millet remains poorly understood. Here, we report the chromosome-scale genome assembly of broomcorn millet. We divided the broomcorn millet genome into two subgenomes using the genome sequence of Panicum hallii, a diploid relative of broomcorn millet. Our analyses revealed that the two subgenomes diverged at ~4.8 million years ago (Mya), while the allotetraploidization of broomcorn millet may have occurred about ~0.48 Mya, suggesting that broomcorn millet is a relatively recent allotetraploid. Comparative analyses showed that subgenome B was larger than subgenome A in size, which was caused by the biased accumulation of long terminal repeat retrotransposons in the progenitor of subgenome B before polyploidization. Notably, the accumulation of biased mutations in the transposable element-rich subgenome B led to more gene losses. Although no significant dominance of either subgenome was observed in the expression profiles of broomcorn millet, we found the minimally expressed genes in P. hallii tended to be lost during diploidization of broomcorn millet. These results suggest that broomcorn millet is at the early stage of diploidization and that mutations likely occurred more on genes that were marked with lower expression levels.

Novel players in organogenesis and flavonoid biosynthesis in cucumber glandular trichomes.

Glandular trichomes (GTs) are outgrowths of plant epidermal cells that secrete and store specialized secondary metabolites that protect plants against biotic and abiotic stresses and have economic importance for human use. While extensive work has been done to understand the molecular mechanisms of trichome organogenesis in Arabidopsis (Arabidopsis thaliana), which forms unicellular, nonglandular trichomes (NGTs), little is known about the mechanisms of GT development or regulation of secondary metabolites in plants with multicellular GTs. Here, we identified and functionally characterized genes associated with GT organogenesis and secondary metabolism in GTs of cucumber (Cucumis sativus). We developed a method for effective separation and isolation of cucumber GTs and NGTs. Transcriptomic and metabolomic analyses showed that flavonoid accumulation in cucumber GTs is positively associated with increased expression of related biosynthesis genes. We identified 67 GT development-related genes, the functions of 7 of which were validated by virus-induced gene silencing. We further validated the role of cucumber ECERIFERUM1 (CsCER1) in GT organogenesis by overexpression and RNA interference transgenic approaches. We further show that the transcription factor TINY BRANCHED HAIR (CsTBH) serves as a central regulator of flavonoid biosynthesis in cucumber GTs. Work from this study provides insight into the development of secondary metabolite biosynthesis in multicellular GTs.

Ameliorative Effect of Malvidin on Spleen Injury in LPS-Induced Sepsis.

Sepsis, one of the most destructive diseases in the world, is a syndrome of systemic inflammatory response caused by the invasion of pathogenic microorganisms such as bacteria into the body. Malvidin is one of the most widespread anthocyanins, and its significant antioxidant and anti-inflammatory activities have been widely reported. However, the effect of Malvidin on sepsis and related complications is still unclear. The present study aimed to determine the mechanisms of Malvidin's potential protection from lipopolysaccharide (LPS)-induced spleen injury model of sepsis. In the LPS-induced mouse spleen injury model of sepsis, pretreatment with Malvidin was performed to assess morphological damage in spleen tissue and to detect the expression of mRNA levels of serum necrosis factor α, interleukin 1ß and interleukin 6, and IL-10. Apoptosis was detected using the TUNEL technique, and the levels of oxidative stress-related oxidase and antioxidant enzymes were measured by kit to assess the effect of Malvidin on inflammation and oxidative stress associated with septic spleen injury. The results of this study indicated that Malvidin was be a potentially effective drug for the treatment of sepsis.

Identification and Functional Characterization of CsMYCs in Cucumber Glandular Trichome Development.

Glandular trichomes (GTs), specialized structures formed by the differentiation of plant epidermal cells, are known to play important roles in the resistance of plants to external biotic and abiotic stresses. These structures are capable of storing and secreting secondary metabolites, which often have important agricultural and medicinal values. In order to better understand the molecular developmental mechanisms of GTs, studies have been conducted in a variety of crops, including tomato (Solanum lycopersicum), sweetworm (Artemisia annua), and cotton (Gossypium hirsutum). The MYC transcription factor of the basic helix-loop-helix (bHLH) transcription factor family has been found to play an important role in GT development. In this study, a total of 13 cucumber MYC transcription factors were identified in the cucumber (Cucumis sativus L.) genome. After performing phylogenetic analyses and conserved motifs on the 13 CsMYCs in comparison to previously reported MYC transcription factors that regulate trichome development, seven candidate MYC transcription factors were selected. Through virus-induced gene silencing (VIGS), CsMYC2 is found to negatively regulate GT formation while CsMYC4, CsMYC5, CsMYC6, CsMYC7, and CsMYC8 are found to positively regulate GT formation. Furthermore, the two master effector genes, CsMYC2 and CsMYC7, are observed to have similar expression patterns indicating that they co-regulate the balance of GT development in an antagonistic way.

The effect of HPV DNA and p16 status on the prognosis of patients with hypopharyngeal carcinoma: a meta-analysis.

OBJECTIVE: To evaluate whether the presence of human papillomavirus (HPV) DNA and p16 might be associated with better prognosis in patients with hypopharyngeal carcinoma (HPC), especially on overall survival (OS) and disease-free survival (DFS). METHOD: PubMed, the Cochrane Library, the Web of Science and EMBASE were searched from inception to April 2021 to search for HPV DNA- and p16-related prognostic articles on HPC. Meta-analysis was performed on the selected articles according to the inclusion and exclusion criteria. Publication bias was assessed for the included studies with Egger's test. All studies were analyzed by using Stata 16.0 statistical software. RESULTS: A total of 18 studies were included, including 12 HPV DNA studies and 11 p16 studies. Meta-analysis showed that HPV DNA positivity was a strong prognostic factor for improved OS in patients with HPC, with a pooled hazard ratio (HR) of 0.61 (95% CI, 0.54-0.69), but there was no statistically significant difference in DFS (HR, 0.60; 95% CI, 0.31-1.16). Patients with p16-positive tumors had better OS (HR, 0.66; 95% CI, 0.49-0.89) and DFS (HR, 0.59; 95% CI, 0.44-0.78) than patients with p16-negative tumors. CONCLUSIONS: This study suggests that the presence of HPV DNA leads to better OS in patients with HPC, and the presence of p16 also corresponds to better OS and DFS. Our results provide up-to-date evidence to clinicians and researchers. Larger studies adjusting for prognostic factors are needed in subsequent studies.

Evolution and diversification of reproductive phased small interfering RNAs in Oryza species.

In grasses, two types of phased, small interfering RNAs (phasiRNAs) are expressed largely in young, developing anthers. They are 21 or 24 nucleotides (nt) in length and are triggered by miR2118 or miR2275, respectively. However, most of their functions and activities are not fully understood. We performed comparative genomic analysis of their source loci (PHAS) in five Oryza genomes and combined this with analysis of high-throughput sRNA and degradome datasets. In total, we identified 8216 21-PHAS and 626 24-PHAS loci. Local tandem and segmental duplications mainly contributed to the expansion and supercluster distribution of the 21-PHAS loci. Despite their relatively conserved genomic positions, PHAS sequences diverged rapidly, except for the miR2118/2275 target sites, which were under strong selection for conservation. We found that 21-nt phasiRNAs with a 5'-terminal uridine (U) demonstrated cis-cleavage at PHAS precursors, and these cis-acting sites were also variable among close species. miR2118 could trigger phasiRNA production from its own antisense transcript and the derived phasiRNAs might reversibly regulate miR2118 precursors. We hypothesised that successful initiation of phasiRNA biogenesis is conservatively maintained, while phasiRNA products diverged quickly and are not individually conserved. In particular, phasiRNA production is under the control of multiple reciprocal regulation mechanisms.

Comparison of Oryza sativa and Oryza brachyantha Genomes Reveals Selection-Driven Gene Escape from the Centromeric Regions.

Centromeres are dynamic chromosomal regions, and the genetic and epigenetic environment of the centromere is often regarded as oppressive to protein-coding genes. Here, we used comparative genomic and phylogenomic approaches to study the evolution of centromeres and centromere-linked genes in the genus Oryza We report a 12.4-Mb high-quality BAC-based pericentromeric assembly for Oryza brachyantha, which diverged from cultivated rice (Oryza sativa) ∼15 million years ago. The synteny analyses reveal seven medium (>50 kb) pericentric inversions in O. sativa and 10 in O. brachyantha Of these inversions, three resulted in centromere movement (Chr1, Chr7, and Chr9). Additionally, we identified a potential centromere-repositioning event, in which the ancestral centromere on chromosome 12 in O. brachyantha jumped ∼400 kb away, possibly mediated by a duplicated transposition event (>28 kb). More strikingly, we observed an excess of syntenic gene loss at and near the centromeric regions (P < 2.2 × 10-16). Most (33/47) of the missing genes moved to other genomic regions; therefore such excess could be explained by the selective loss of the copy in or near centromeric regions after gene duplication. The pattern of gene loss immediately adjacent to centromeric regions suggests centromere chromatin dynamics (e.g., spreading or microrepositioning) may drive such gene loss.

Novel CD44-targeting and pH/redox-dual-stimuli-responsive core-shell nanoparticles loading triptolide combats breast cancer growth and lung metastasis.

BACKGROUND: The toxicity and inefficient delivery of triptolide (TPL) in tumor therapy have greatly limited the clinical application. Thus, we fabricated a CD44-targeting and tumor microenvironment pH/redox-sensitive nanosystem composed of hyaluronic acid-vitamin E succinate and poly (ß-amino esters) (PBAEss) polymers to enhance the TPL-mediated suppression of breast cancer proliferation and lung metastasis. RESULTS: The generated TPL nanoparticles (NPs) had high drug loading efficiency (94.93% ± 2.1%) and a desirable average size (191 nm). Mediated by the PBAEss core, TPL/NPs displayed a pH/redox-dual-stimuli-responsive drug release profile in vitro. Based on the hyaluronic acid coating, TPL/NPs exhibited selective tumor cellular uptake and high tumor tissue accumulation capacity by targeting CD44. Consequently, TPL/NPs induced higher suppression of cell proliferation, blockage of proapoptotic and cell cycle activities, and strong inhibition of cell migration and invasion than that induced by free TPL in MCF-7 and MDA-MB-231 cells. Importantly, TPL/NPs also showed higher efficacy in shrinking tumor size and blocking lung metastasis with decreased systemic toxicity in a 4T1 breast cancer mouse model at an equivalent or lower TPL dosage compared with that of free TPL. Histological immunofluorescence and immunohistochemical analyses in tumor and lung tissue revealed that TPL/NPs induced a high level of apoptosis and suppressed expression of matrix metalloproteinases, which contributed to inhibiting tumor growth and pulmonary metastasis. CONCLUSION: Collectively, our results demonstrate that TPL/NPs, which combine tumor active targeting and pH/redox-responsive drug release with proapoptotic and antimobility effects, represent a promising candidate in halting breast cancer progression and metastasis while minimizing systemic toxicity.

[Mechanisms and application of triptolide against breast cancer].

Overtaking lung cancer,breast cancer is now the most commonly diagnosed cancer seriously threatening people's health and life. As the main effective component of Tripterygium wilfordii,triptolide( TP) has attracted increasing attention due to its multitarget and multi-pathway anti-tumor activity. Recent studies have revealed that breast cancer-sensitive TP enables the inactivation of breast cancer cells by inducing tumor cell apoptosis and autophagy,interfering in tumor cell metastasis,resisting drug resistance,arresting tumor cell cycle,and influencing tumor microenvironment. It has been recognized as a promising clinical antitumor agent by virtue of its widely accepted therapeutic efficacy. This paper reviewed the anti-breast cancer action and its molecular mechanisms of TP on the basis of the relevant literature in the past ten years,and proposed application strategies in view of the inadequacy of TP to provide a reference for further research on the application of TP in the treatment of breast cancer.

[Prescription compatibility connotation and action mechanism of Siwu Decoction in treating primary dysmenorrhea].

The aim of this paper was to study the prescription compatibility connotation in the treatment of primary dysmenorrhea(PD) and verify the mechanism as predicted by network pharmacology of Siwu Decoction(SWD). Mice PD model was constructed by using estradiol benzoate-oxytocin. PD mice were randomly divided into 8 groups, namely normal group, model group, positive group, complete formula group, Rehmanniae Radix Praeparata-free group, Paeoniae Radix Alba-free group, volatile oil-free group, Chuan-xiong Rhizoma and Angelicae Sinensis Radix-free group. Latent time, writhing times, inhibition rate, prostaglandin F_2_α(PGF_2_α) and prostaglandin E_2(PGE_2) levels in serum, endothelin-1, Ca~(2+), expression levels of prostaglandin synthase 2 G/H(PTGS2), estrogen receptor(ESR1), glucocorticoid receptor gene(NR3 C1) mRNA and protein expression levels in the uterus homogenate and pathological changes of uterine tissue were index to explore the prescription compatibility connotation and verify the mechanism of SWD in the treatment of PD. Compared with the extraction liquid of the whole recipe, the effect of Rehmanniae Radix Praeparata-free group and Paeoniae Radix Alba-free group with volatile oil were slightly lower, the effect of essential oil-free group was significantly lower, and the effect of Chuanxiong Rhizoma and Angelicae Sinensis Radix-free group was worse than that of the whole recipe. The relative expression levels of PTGS2 protein and mRNA were significantly reduced by the SWD. The relative expressions of protein and mRNA of ESR1, NR3 C1 were significantly increased. SWD treats PD by regulating the expression of key proteins PTGS2, ESR1 and NR3 C1.Its main medicinal herbs were Angelicae Sinensis Radix and Chuanxiong Rhizoma. Active components were mainly in volatile oil, but Paeo-niae Radix Alba and Rehmanniae Radix Praeparata also had some contributions.

[Pharmacodynamics of Siwu Decoction on blood supply based on factor analysis].

To evaluate the pharmacodynamic effect of Siwu Decoction in treating blood deficiency in mice under multidimensional pharmacodynamic indexes by factor analysis. The mouse blood deficiency model was established with cyclophosphamide combined with acetophenone; and mouse organ index,white blood cells,red blood cell,hemoglobin,platelet counts in whole blood,serum granulocyte-macrophage colony-stimulating factor,macrophagecolony-stimulating factor,promotion erythropoietin,interleukin-3 and interleukin-6 were used as indicators to characterize the blood-enriching effect of Siwu Decoction; the pharmacodynamic effect of Siwu Decoction on blood deficiency model was evaluated comprehensively by factor analysis. Four common factors were extracted from 14 pharmacodynamics indexes through the factor analysis,namely blood phase factor,viscera index,hematopoietic regulatory factor 1-spleen index and hematopoietic regulatory factor 2-viscera index. The cumulative contribution rate of variance reached 86. 581%. The comprehensive score of factor analysis showed that Siwu Decoction had the best effect on blood replenishment,and it is significant compared with the model group( P<0. 01). The effect of alcohol precipitation of Siwu Decoction was slightly decreased. The study showed that Siwu Decoction has the best blood-enriching effect,followed by water decoction and traditional decoction. Alcohol precipitation had the worst effect. Factor analysis can be used for the comprehensive evaluation of blood deficiency mice model,and is a suitable evaluation method for animal model for multi-dimensional multistage complex data analysis. It provides a new model to evaluate the efficacy of multidimensional data in the future.

[Network pharmacology-based study on mechanism of Siwu Decoction in treatment of primary dysmenorrhea].

This paper aimed to predict and explore the mechanism of multiple components, targets and pathways of Siwu decoction for treatment of primary dysmenorrhea, and to establish a network pharmacological model of "compound-target-pathway-disease". According to the active ingredients in Siwu Decoction, Swiss Target Prediction server was used to predict the active component targets based on the reverse pharmacodynamic group matching method, and the primary dysmenorrhea targets approved by FDA were selected by database including DrugBank, OMIM and TTD. According to the enrichment analysis of the target pathways by using KEGG, the Cytoscape software was used to construct the network of "compound-target-pathway-disease" of Siwu Decoction. Network analysis showed that there were 20 active components involved in 114 pathways. And 16 components, 16 target proteins and 24 pathways were related to primary dysmenorrhea. Siwu Decoction may play a role in treating primary dysmenorrhea by acting on protein targets and pathways related to hormone regulation, central analgesia, spasmolysis,inflammation and immunity. This study revealed the potential active compounds and possible mechanism of Siwu Decoction for treatment of primary dysmenorrhea, providing theoretical references for further systematic laboratory experiments on effective compounds and action mechanism of Siwu Decoction.

[Research progress on triptolide functionalized nanoparticulate drug delivery systems for tumor treatment].

Nowadays,the advantages of traditional Chinese medicine(TCM) for treatment of tumors are increasingly prominent.Triptolide shows wide-spectrum and highly effective anti-tumor activity. Moreover,nano-carrier-based triptolide drug delivery system is more powerful in improving water solubility and pharmacokinetic behavior of the drug,but it is easy to cause toxic and side effects that should not be neglected on human body. Because of tumor vascular heterogeneity and PEGylation dilemma,nanoparticulate drug delivery systems need to overcome multiple physiological and pathological barriers from drug administration to functioning. It is difficult for traditional triptolide nanoparticulate drug delivery systems to achieve active accumulation of nano-drug in tumor tissues and specific drug release in tumor target site solely relying on enhanced permeability and retention effect of solid tumor,limiting their application and clinical transformation in treatment of tumors. Based on the traditional nano-preparation system,the new functionalized nano-drug delivery system further enhances the nano-drug enrichment,penetration and controlled release at the tumor sites,which is of great significance in improving bioavailability,anti-tumor efficacy and reducing the side effects of drugs. In this paper,we summarized and analyzed the researches on new triptolide functionalized nano-drug delivery system from four perspectives,including tumor active targeting,tumor microenvironment response,polymer-drug conjugates,and multidrug co-delivery for tumor treatment,expecting to provide ideas for in-depth research and clinical application of triptolide and some other active anti-tumor TCM ingredients.

[Research progress on anti-tumor effects and mechanisms of triptolide and its combined application].

Tumors are major chronic diseases and seriously threaten human health all over the world. How to effectively control and cure tumors is one of the most pivotal problems in the medical field. At present,surgery,radiotherapy and chemotherapy are still the main treatment methods. However,the side effects of radiotherapy and chemotherapy cannot be underestimated. Therefore,it is of great practical significance to find new anti-cancer drugs with low toxicity,high efficiency and targeting to cancer cells. With the increasing incidence of tumor,the anti-tumor effect of traditional Chinese medicine has increasingly become a research hotspot. Triptolide,which is a natural diterpenoid active ingredient derived from of Tripterygium wilfordii,as one of the highly active components,has anti-inflammatory,immunosuppressive,anti-tumor and other multiple effects. A large number of studies have confirmed that it has good anti-tumor activity against various tumors in vivo and in vitro. It can play an anti-tumor role by inhibiting the proliferation of cancer cells,inducing apoptosis of cancer cells,inducing autophagy of cancer cells,blocking the cell cycle,inhibiting the migration,invasion and metastasis of cancer cells,reversing multidrug resistance,mediating tumor immunity and inhibiting angiogenesis. On the basis of literatures,this paper reviews the anti-tumor effect and mechanism of triptolide,and analyzes the current situation of triptolide combined with other chemotherapy drugs,in order to promote deep research and better clinical application about triptolide.

Design, analysis of self-configurable modular adjustable latch lock for segmented space mirrors.

This paper presents a connection mechanism for autonomous self-assembly of segmented space mirrors. Using this connection mechanism, space mirrors can be autonomously captured, positioned, locked and adjusted. The purpose of assembling space mirrors on orbit is to overcome the limits of launch volume and mass and provide a feasibility for future extremely large space telescope in order to improve optical performance to function as monolithic mirrors. In this paper, first, the design details and operation principle of the connection mechanism are presented. Then, based on the initial capture conditions, a double-contact model is investigated. And simulated results of the dynamic and optical performance show that the proposed mechanism overcomes significant alignment errors and is considered suitable for space optical system.

[Dissolution behavior of Fuzi Lizhong pill based on simultaneous determination of two components in Glycyrrhizae Radix et Rhizoma].

To preliminarily investigate the dissolution behavior of Fuzi Lizhong pill, provide the basis for its quality control and lay foundation for in vivo dissolution behavior by determining the dissolution rate of liquiritin and glycyrrhizic acid. High-performance liquid chromatography (HPLC) method for simultaneous content determination of the two active ingredients of liquiritin and glycyrrhizic acid in Fuzi Lizhong pill was established; The dissolution amount of these two active ingredients in fifteen batches of Fuzi Lizhong pill from five manufacturers was obtained at different time points, and then the cumulative dissolution rate was calculated and cumulative dissolution curve was drawn. The similarity of cumulative dissolution curve of different batches was evaluated based on the same factory, and the similarity of cumulative dissolution curve of different factories was evaluated based on the same active ingredients. The dissolution model of Fuzi Lizhong pill based on two kinds of active ingredients was established by fitting with the dissolution data. The best dissolution medium was 0.25% sodium lauryl sulfate. The dissolution behavior of liquiritin and glycyrrhizic acid in Fuzi Lizhong pill was basically the same and sustained release in 48 h. Three batches of the factories (factory 2, factory 3, factory 4 and factory 5) appeared to be similar in dissolution behavior, indicating similarity in dissolution behavior in most factories. Two of the three batches from factory 1 appeared to be not similar in dissolution behavior of liquiritin and glycyrrhizic acid. The dissolution data of the effective ingredients from different factories were same in fitting, and Weibull model was the best model in these batches. Fuzi Lizhong pill in 15 batches from 5 factories showed sustained release in 48 h, proving obviously slow releasing characteristics "pill is lenitive and keeps a long-time efficacy". The generally good dissolution behavior also suggested that quality of different batches from most factories was stable. The dissolution behavior of liquiritin and glycyrrhizic acid in different factories was different, suggesting that the source of medicinal materials and preparation technology parameters in five factories were different.

[Analysis on dosage form theory and current application situation of traditional Chinese medicine pill].

Traditional Chinese medicine(TCM) pill, the most representative and successive dosage form, is called as one of the four classical TCM dosage forms. "Pills could keep the lasting and lenitive therapeutic efficacy for a long period" is the most classical dosage form theory, showing a guidance significance in making recipe, preparations and clinic application. In this article, we would elucidate the inheritance and development significance of TCM pills in three key points, including dosage form theory, pharmaceutical preparation technology and clinic usage based on the pharmaceutics connotation of this theory. From this, it can provide the basis for researches on pills mechanism, material basis and mode of action in clinical application.

[Serum amyloid A promotes the inflammatory response via p38-MAPK/SR-BI pathway in THP-1 macrophages].

To investigate the effect and mechanism of serum amyloid A (SAA) on the expression of scavenger receptor class B type I (SR-BI) and inflammatory response in THP-1 macrophages, the human THP-1 cells were treated with SAA and p38-MAPK agonist (anisomycin) or p38-MAPK inhibitor (SB203580). Then, the expressions of SR-BI, phosphorylated p38-MAPK and inflammatory factors (MCP-1, TNF-α, IL-1ß) were examined by real-time quantitative PCR, Western blotting and ELISA, respectively. The results showed that, compared with control group, SAA increased the levels of inflammatory factors (MCP-1, TNF-α, IL-1ß), down-regulated the expressions of SR-BI, and up-regulated the expression of phosphorylated p38-MAPK protein in a concentration- and time-dependent manner in THP-1 cells (P < 0.05). After treatment with SAA and p38-MAPK agonist (anisomycin) in THP-1 cells, the expression of SR-BI was down-regulated, and the levels of inflammatory factors and phosphorylated p38-MAPK protein expression were increased, compared with the group only treated by SAA (P < 0.05). In contrast, the SR-BI expression was up-regulated, whereas inflammatory factors and phosphorylated p38-MAPK protein expressions were decreased after the cells were treated with SAA and p38-MAPK inhibitor (SB203580) (P < 0.05). The results suggest that SAA-promoted inflammatory response in THP-1 macrophages may be through the phosphorylation of p38-MAPK and inhibition of SR-BI expression.

Genomic, regulatory and epigenetic mechanisms underlying duplicated gene evolution in the natural allotetraploid Oryza minuta.

BACKGROUND: Polyploid species contribute to Oryza diversity. However, the mechanisms underlying gene and genome evolution in Oryza polyploids remain largely unknown. The allotetraploid Oryza minuta, which is estimated to have formed less than one million years ago, along with its putative diploid progenitors (O. punctata and O. officinalis), are quite suitable for the study of polyploid genome evolution using a comparative genomics approach. RESULTS: Here, we performed a comparative study of a large genomic region surrounding the Shattering4 locus in O. minuta, as well as in O. punctata and O. officinalis. Duplicated genomes in O. minuta have maintained the diploid genome organization, except for several structural variations mediated by transposon movement. Tandem duplicated gene clusters are prevalent in the Sh4 region, and segmental duplication followed by random deletion is illustrated to explain the gene gain-and-loss process. Both copies of most duplicated genes still persist in O. minuta. Molecular evolution analysis suggested that these duplicated genes are equally evolved and mostly manipulated by purifying selection. However, cDNA-SSCP analysis revealed that the expression patterns were dramatically altered between duplicated genes: nine of 29 duplicated genes exhibited expression divergence in O. minuta. We further detected one gene silencing event that was attributed to gene structural variation, but most gene silencing could not be related to sequence changes. We identified one case in which DNA methylation differences within promoter regions that were associated with the insertion of one hAT element were probably responsible for gene silencing, suggesting a potential epigenetic gene silencing pathway triggered by TE movement. CONCLUSIONS: Our study revealed both genetic and epigenetic mechanisms involved in duplicated gene silencing in the allotetraploid O. minuta.

[Effect of PFT-α on apoptosis of spermatogenic cells caused by enorchia].

OBJECTIVE: To determine the molecular mechanism of germ cell apoptosis via investigating the effect of PFT-α on the expression of p53 and bcl-2/bax during experimental cryptorchid cell apoptosis. METHODS: Male Sprague-Dawley rats were assigned into 4 groups: a sham-operated group, a cryptorchid group, a cryptorchid+p53 inhibitor (p53 inhibitor-alpha, PFT-α) group, and a cryptorchid+dissolvent of PFT-α [dimethyl sulphoxide (DMSO)] group. Unilateral cryptorchidism was surgically induced in the rats of the cryptorchid group, PFT-α group, and cryptorchid+dissolvent of PFT-α group. The rats in the PFT-α group and cryptorchid+dissolvent of PFT-α group were intra-peritoneally injected PFT-α and dissolvent of PFT-α, respectively, once a day. The rats were killed on the 7th day after the surgery. The morphology of spermatogenic epithelium at the side of surgery in the rats was observed under light microscope. The apoptosis of spermatogenic cells in the unilateral cryptorchidism was evaluated by TUNEL and flow cytometry (FCM). The protein expression levels of p53, bcl-2, and Bax were detected by Western blot and immunohistochemical assay in turn. RESULTS: Compared with the cryptorchid groups and the cryptorchid+dissolvent of PFT-α group, the seminiferous epithelium of the cryptorchid+p53 inhibitor group appeared orderly, with thicker cell layers and lower apoptosis index, weak protein expression level of p53/Bax and strong protein expression level of bcl-2. CONCLUSION: PFT-α inhibits the germ cell apoptosis caused by the experimental cryptorchidism via increasing the expression of bcl-2 and decreasing the expression of p53 and bax.