The ARID-HMG DNA-binding protein AtHMGB15 is required for pollen tube growth in Arabidopsis thaliana.

In flowering plants, male gametes (sperm cells) develop within male gametophytes (pollen grains) and are delivered to female gametes for double fertilization by pollen tubes. Therefore, pollen tube growth is crucial for reproduction. The mechanisms that control pollen tube growth remain poorly understood. In this study, we demonstrated that the ARID-HMG DNA-binding protein AtHMGB15 plays an important role in pollen tube growth. This protein is preferentially expressed in pollen grains and pollen tubes and is localized in the vegetative nuclei of the tricellular pollen grains and pollen tubes. Knocking down AtHMGB15 expression via a Ds insertion caused retarded pollen tube growth, leading to a significant reduction in the seed set. The athmgb15-1 mutation affected the expression of 1686 genes in mature pollen, including those involved in cell wall formation and modification, cell signaling and cellular transport during pollen tube growth. In addition, it was observed that AtHMGB15 binds to DNA in vitro and interacts with the transcription factors AGL66 and AGL104, which are required for pollen maturation and pollen tube growth. These results suggest that AtHMGB15 functions in pollen tube growth through the regulation of gene expression.

Comparison between absolute ethanol and bleomycin for the treatment of venous malformation in children.

The aim of this study was to investigate the therapeutic efficacies and treatment effects of absolute ethanol and bleomycin for the treatment of venous malformation (VM) in children. A total of 138 children with VM were randomly divided into two groups; 75 patients were treated with absolute ethanol, while a further 63 were treated with bleomycin under general anesthesia between February 2009 and February 2012. The treatment outcome and complications were observed in the two groups and the treatment efficacy was classified as one of four categories: cured, markedly effective, effective and ineffective. The curative effect was analyzed 6-24 months after treatment, with a mean of 15 months. Absolute ethanol was effective (cured, markedly effective or effective) in 71 cases and bleomycin was effective in 41 cases, and the difference between the effective rates was considered to be statistically significant (χ2=19.6, P<0.05). In the absolute ethanol group there were 14 cases with skin necrosis, 17 patients had serious localized swelling which required additional treatment, three patients developed muscle fibrosis and one patient suffered a brain embolism. In the bleomycin group there were five cases with skin necrosis and the difference in the incidence of adverse reactions was considered to be statistically significant (χ2=18.8, P<0.05). The curative effect of sclerotherapy for VM is clear, and absolute ethanol is the most effective sclerosing agent, but has a greater incidence of adverse side-effects than bleomycin. The major side-effect is skin necrosis. The choice of sclerotherapy depends on the classification of VM in children.

Interventional embolization therapy of puerile congenital deep femoral arteriovenous fistula.

This study aimed to investigate the treatment efficiency of interventional embolization therapy in puerile congenital deep femoral arteriovenous fistula. A retrospective analysis was conducted for 9 cases of congenital deep femoral arteriovenous fistulae treated in our department in the past 5 years. B-ultrasound examination indicated that all puerile patients suffered from deep femoral arteriovenous fistulae, which was confirmed by angiography examination. For all patients, endovascular interventional embolization therapy was conducted and angiography re-examination was implemented after 4 weeks. If there were residual orificium fistulae, the interventional embolization therapy was conducted again. In the 6 month to 2 year follow-up period, improvement of clinical symptoms was observed. Following interventional embolization, 9 cases of deep femoral arteriovenous fistulae were completely occluded and the clinical symptoms were improved. No relapses occurred. In addition, after three embolization treatments, the disease condition of one case was controlled well and the disease condition did not progress. Interventional embolization therapy has a number of advantages, including simple surgery and reliable treatment efficacy. Therefore, it is worthy of promotion and application in the clinic.

Arabidopsis CSLD1 and CSLD4 are required for cellulose deposition and normal growth of pollen tubes.

The cell wall is important for pollen tube growth, but little is known about the molecular mechanism that controls cell wall deposition in pollen tubes. Here, the functional characterization of the pollen-expressed Arabidopsis cellulose synthase-like D genes CSLD1 and CSLD4 that are required for pollen tube growth is reported. Both CSLD1 and CSLD4 are highly expressed in mature pollen grains and pollen tubes. The CSLD1 and CSLD4 proteins are located in the Golgi apparatus and transported to the plasma membrane of the tip region of growing pollen tubes, where cellulose is actively synthesized. Mutations in CSLD1 and CSLD4 caused a significant reduction in cellulose deposition in the pollen tube wall and a remarkable disorganization of the pollen tube wall layers, which disrupted the genetic transmission of the male gametophyte. In csld1 and csld4 single mutants and in the csld1 csld4 double mutant, all the mutant pollen tubes exhibited similar phenotypes: the pollen tubes grew extremely abnormally both in vitro and in vivo, which indicates that CSLD1 and CSLD4 are not functionally redundant. Taken together, these results suggest that CSLD1 and CSLD4 play important roles in pollen tube growth, probably through participation in cellulose synthesis of the pollen tube wall.

Mutations in the Arabidopsis nuclear-encoded mitochondrial phage-type RNA polymerase gene RPOTm led to defects in pollen tube growth, female gametogenesis and embryogenesis.

The mitochondrial genes in Arabidopsis thaliana are transcribed by a small family of nuclear-encoded T3/T7 phage-type RNA polymerases (RPOTs). At least two nuclear-encoded RPOTs (RPOTm and RPOTmp) are located in mitochondria in A. thaliana. Their genetic roles are largely unknown. Here we report the characterization of novel mutations in the A. thaliana RPOTm gene. The mutations did not affect pollen formation, but significantly retarded the growth of the rpoTm mutant pollen tubes and had an impact on the fusion of the polar nuclei in the rpoTm mutant embryo sacs. Moreover, development of the rpoTm/- mutant embryo was arrested at the globular stage. The rpoTm rpoTmp double mutation could enhance the rpoTm mutant phenotype. Expression of RPOTmp under control of the RPOTm promoter could not complement the phenotype of the rpoTm mutations. All these data indicate that RPOTm is important for normal pollen tube growth, female gametogenesis and embryo development, and has distinct genetic and molecular roles in plant development, which cannot be replaced by RPOTmp.

GNOM-LIKE 2, encoding an adenosine diphosphate-ribosylation factor-guanine nucleotide exchange factor protein homologous to GNOM and GNL1, is essential for pollen germination in Arabidopsis.

In flowering plants, male gametes are delivered to female gametophytes by pollen tubes. Although it is important for sexual plant reproduction, little is known about the genetic mechanism that controls pollen germination and pollen tube growth. Here we report the identification and characterization of two novel mutants, gnom-like 2-1 (gnl2-1) and gnl2-2 in Arabidopsis thaliana, in which the pollen grains failed to germinate in vitro and in vivo. GNL2 encodes a protein homologous to the adenosine diphosphate-ribosylation factor-guanine nucleotide exchange factors, GNOM and GNL1 that are involved in endosomal recycling and endoplasmic reticulum-Golgi vesicular trafficking. It was prolifically expressed in pollen grains and pollen tubes. The results of the present study suggest that GNL2 plays an important role in pollen germination.

[Molecular cloning and expression of human PDGF-B chain mature peptide gene].

OBJECTIVE: To acquire sufficient PDGF-BB protein and provide the basis for the further studies of its role on the fracture healing and trauma reconstruction and its clinical applications. METHODS: Constructed the prokaryotic expression vector pQE-PDGF-B with the gene rearrangement technique, and the monomeric form of recombinant PDGF-B expressed in E. coli M15. RESULTS: PDGF-B mature peptide gene was inserted into prokaryotic expression vector pQE30, which was confirmed by PCR, enzyme digestion and sequencing identification; the expressed products of pQE-PDGF-B in E. coli showed a single protein on SDS-PAGE, and their expression level was about 15% of the total bacterial protein. The molecular weight of the purified PDGF-B protein was about 15 KDs on SDS-PAGE. CONCLUSIONS: The construction of recombinant plasmid and preparation of the monomeric protein of PDGF-B provides a solid foundation for further studying the function of PDGF-BB and producing biologically PDGF-BB protein.

[Construction and identification of yeast expression vectors containing human platelet-derived growth factor B-chain gene].

OBJECTIVE: To investigate the expression efficiency of human platelet-derived growth factor B-chain (PDGF-B) gene in yeast and assess the activity of the expressed product. METHODS: A full-length complementary DNA of human PDGF-B gene was amplified from the total RNA extracted from human vascular endothelial cells using reverse transcription (RT)-PCR and then cloned into pGEM-T vector. The PCR products with specific primers were recombined into yeast expression plasmids pMETB or pMETalphaA, followed by identification with restriction endonuclease. RESULTS: The 578 bp fragment encoding mature PDGF-BB peptide with signal peptide and the 340 bp fragment without signal peptide were identified and verified by restriction endonuclease mapping and sequencing, and two yeast expression vectors pMETB-PDGFB(1) and pMETalphaA-PDGFB(2) were reconstructed. CONCLUSION: The yeast expression vectors containing human PDGF-B gene have been successfully constructed for further studies of gene expression in yeast.