Intertissue flow of glutathione (GSH) as a tumor growth-promoting mechanism: interleukin 6 induces GSH release from hepatocytes in metastatic B16 melanoma-bearing mice

B16 melanoma F10 (B16-F10) cells with high glutathione (GSH) content show high metastatic activity in vivo. An intertissue flow of GSH, where the liver is the main reservoir, can increase GSH content in metastatic cells and promote their growth. We have studied here possible tumor-derived molecular signals that could activate GSH release from hepatocytes. GSH efflux increases in hepatocytes isolated from mice bearing liver or lung metastases, thus suggesting a systemic mechanism. Fractionation of serum-free conditioned medium from cultured B16-F10 cells and monoclonal antibody-induced neutralization techniques facilitated identification of interleukin (IL)-6 as a tumor-derived molecule promoting GSH efflux in hepatocytes. IL-6 activates GSH release through a methionine-sensitive/organic anion transporter polypeptide 1- and multidrug resistance protein 1-independent channel located on the sinusoidal site of hepatocytes. Specific siRNAs were used to knock down key factors in the main signaling pathways activated by IL-6, which revealed a STAT3-dependent mechanism. Our results show that IL-6 (mainly of tumor origin in B16-F10-bearing mice) may facilitate GSH release from hepatocytes and its interorgan transport to metastatic growing foci.     

A case of furuncular myiasis associated with systemic inflammation

Cutaneous myiasis is a common travel-associated dermatosis caused by fly larvae. We report an unusual case of furuncular myiasis caused by Dermatobia hominis that was associated with signs of systemic inflammation. In this case study, morphological and novel molecular approaches were used to identify and characterize the larvae responsible for human infestation.     

水稻淀粉合成的分子生物学研究进展

本文综述了水稻淀粉合成的分子生物学研究的最新进展,主要内容是参与淀粉合成的酶鉴定及其基因表达调控,也介绍了对这些酶的遗传操作改良稻米淀粉品质等内容     

Evolutionarily evolved discriminators in the 3-TPR domain of the Toc64 family involved in protein translocation at the outer membrane of chloroplasts and mitochondria

Transport of polypeptides across membranes is a general and essential cellular process utilised by molecular machines. At least one component of these complexes contains a domain composed of three tetratricopeptide repeat (3-TPR) motifs. We have focussed on the receptor Toc64 to elucidate the evolved functional specifications of its 3-TPR domain. Toc64 is a component of the Toc core complex and functionally replaces Tom70 at the outer membrane of mitochondria in plants. Its 3-TPR domain recognises the conserved C-terminus of precursor-bound chaperones. We built homology models of the 3-TPR domain of chloroplastic Toc64 from different species and of the mitochondrial isoform from Arabidopsis. Guided by modelling, we identified residues essential for functional discrimination of the differently located isoforms to be located almost exclusively on the convex surface of the 3-TPR domain. The only exception is at568Ser/ps557Met, which is positioned in the ligand-binding groove. The functional implications of the homology models are discussed. Figure Motion contained within the 2nd eigenvector of the Calpha covariance matrix of the 3-TPR domain of atToc64-V indicated by a porcupine plot Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Functional dissection of LIS1 and NDEL1 towards understanding the molecular mechanisms of cytoplasmic dynein regulation

LIS1 and NDEL1 are known to be essential for the activity of cytoplasmic dynein in living cells. We previously reported that LIS1 and NDEL1 directly regulated the motility of cytoplasmic dynein in an in vitro motility assay. LIS1 suppressed dynein motility and inhibited the translocation of microtubules (MTs), while NDEL1 dissociated dynein from MTs and restored dynein motility following suppression by LIS1. However, the molecular mechanisms and detailed interactions of dynein, LIS1, and NDEL1 remain unknown. In this study, we dissected the regulatory effects of LIS1 and NDEL1 on dynein motility using full-length or truncated recombinant fragments of LIS1 or NDEL1. The C-terminal fragment of NDEL1 dissociated dynein from MTs, whereas its N-terminal fragment restored dynein motility following suppression by LIS1, demonstrating that the two functions of NDEL1 localize to different parts of the NDEL1 molecule, and that restoration from LIS1 suppression is caused by the binding of NDEL1 to LIS1, rather than to dynein. The truncated monomeric form of LIS1 had little effect on dynein motility, but an artificial dimer of truncated LIS1 suppressed dynein motility, which was restored by the N-terminal fragment of NDEL1. This suggests that LIS1 dimerization is essential for its regulatory function. These results shed light on the molecular interactions between dynein, LIS1, and NDEL1, and the mechanisms of cytoplasmic dynein regulation.     

Could cancer and infection be adverse effects of mesenchymal stromal cell therapy?

Multipotent mesenchymal stromal cells [also referred to as mesenchymal stem cells(MSCs)] are a heterogeneous subset of stromal cells. They can be isolated from bone marrow and many other types of tissue. MSCs are currently being tested for therapeutic purposes(i.e., improving hematopoietic stem cell engraftment, managing inflammatory diseases and regenerating damaged organs). Their tropism for tumors and inflamed sites and their context-dependent potential for producing trophic and immunomodulatory factors raises the question as to whether MSCs promote cancer and/or infection. Thisarticle reviews the effect of MSCs on tumor establishment, growth and metastasis and also susceptibility to infection and its progression. Data published to date shows a paradoxical effect regarding MSCs, which seems to depend on isolation and expansion, cells source and dose and the route and timing of administration. Cancer and infection may thus be adverse or therapeutic effects arising form MSC administration.     

WD Repeat-containing Protein 5 (WDR5) Localizes to the Midbody and Regulates Abscission

Cytokinesis partitions the cytoplasm of a parent cell into two daughter cells and is essential for the completion of cell division. The final step of cytokinesis in animal cells is abscission, which is a process leading to the physical separation of two daughter cells. Abscission requires membrane traffic and microtubule disassembly at a specific midbody region called the secondary ingression. Here, we report that WD repeat-containing protein 5 (WDR5), a core subunit of COMPASS/MLL family histone H3 lysine 4 methyltransferase (H3K4MT) complexes, resides at the midbody and associates with a subset of midbody regulatory proteins, including PRC1 and CYK4/MKLP1. Knockdown of WDR5 impairs abscission and increases the incidence of multinucleated cells. Further investigation revealed that the abscission delay is primarily due to slower formation of secondary ingressions in WDR5 knockdown cells. Consistent with these defects, midbody microtubules in WDR5 knockdown cells also display enhanced resistance to depolymerization by nocodazole. Recruitment of WDR5 to the midbody dark zone appears to require integrity of the WDR5 central arginine-binding cavity, as mutations that disrupt histone H3 and MLL1 binding to this pocket also abolish the midbody localization of WDR5. Taken together, these data suggest that WDR5 is specifically targeted to the midbody in the absence of chromatin and that it promotes abscission, perhaps by facilitating midbody microtubule disassembly.     

Synthesis and conformational analysis of 1,2-cis fused bicyclic α-d-galactofuranosyl thiocarbamate from per-O-tert-butyldimethylsilyl-β-d-galactofuranosyl isothiocyanate

Per-O-tert-butyldimethylsilyl-α,β-d-galactofuranosyl isothiocyanate (4) was synthesized by the reaction of per-O-TBS-β-d-galactofuranose (1) with KSCN, promoted by TMSI. Upon O-desilylation (1,2-dideoxy-α-d-galactofuranoso)[1,2d]-1,3-oxazolidine-2-thione (6), the cis-fused bicyclic thiocarbamate was obtained as the only product. Conformational analysis, aided by molecular modelling, showed two stable twist forms (³T₄ and ⁴T_O) for the five-membered sugar ring in 6. In aqueous solution, the equilibrium favours the first conformation (3:1 ratio). On the other hand, this ratio decreases for less polar solvents.     

Isolation and Amplification of Genomic DNA from Recalcitrant Dried Berries of Black Pepper (<Emphasis Type="Italic">Piper nigrum</Emphasis> L.)—A Medicinal Spice

Black pepper is an important medicinal spice traded internationally. The extraction of high quality genomic DNA for PCR amplification from dried black pepper is challenging because of the presence of the exceptionally large amount of oxidized polyphenolic compounds, polysaccharides and other secondary metabolites. Here we report a modified hexadecyl trimethyl ammonium bromide (CTAB) protocol by incorporating potassium acetate and a final PEG precipitation step to isolate PCR amplifiable genomic DNA from dried and powdered berries of black pepper. The protocol has trade implication as it will help in the PCR characterization of traded black peppers from different countries.