Adsorption characteristics of lignosulfonates in salt-free and salt-added aqueous solutions

Five sodium lignosulfonate (SL) fractions with narrow molecular weight distribution and known salt content were used as the polyanion to build up layer-by-layer self-assembly multilayers with poly(diallyldimethylammonium chloride) (PDAC) as polycation. It is interesting to find that the salt-free SL is hardly adsorbed on the PDAC surface, but the SL in salt-added solutions can be self-assembled well with PDAC to form SL/PDAC multilayers. When the five SL fractions dissolved in saline solutions are adsorbed on the PDAC surface by a self-assembly technique, SL with higher M(w) shows a higher adsorption amount than does SL with lower M(w). The driving forces of self-assembly of SL and PDAC are discussed based on the solution behaviors and adsorption characteristics of SL in salt-free and salt-added aqueous solutions. A possible self-assembled mechanism of SL and PDAC is electrostatic or cation-π interactions, but the SL cannot be adsorbed onto the PDAC surface without a hydrophobic interaction. With the addition of enough salt, the Coulomb interaction of SL becomes negligible, but the adsorption amount increases, indicating that the electrostatic interaction is not the main driving force of SL/PDAC self-assembly. For adsorption of SL in saline solution onto the PDAC surface, the cation-π interaction is the main driving force, and the hydrophobic interaction plays an important role in the adsorbed amount.     

Single nucleotide polymorphisms of the prolactin receptor (PRLR) gene and its association with growth traits in chinese cattle

Genetic polymorphism of the prolactin receptor (PRLR) gene was detected by PCR-SSCP and DNA sequencing methods in 665 individuals from five Chinese cattle breeds. The results showed that at the P1 locus, three observed genotypes (AA, AB and BB), two linked SNPs (G1267A and T1268C), and one missense mutation (S18N) within a putative signal peptide were determined. The frequencies of haplotypes A and B in the five breeds were 0.596–0.802 and 0.198–0.404, respectively. Polymorphism of the PRLR gene was shown to be significantly associated with growth traits in the Nanyang breed. Individuals with genotype BB had greater hucklebone width, body weight and average daily gain than those with genotype AA at 6 months old (P < 0.01), as well as better body height, body length and heart girth when 6 months (P < 0.05). This study revealed for the first time that the PRLR gene is a promising candidate gene that affects growth traits in cattle.     

Genetic variants in the KIF6 region and coronary event reduction from statin therapy

A single nucleotide polymorphism (SNP) in KIF6, a member of the KIF9 family of kinesins, is associated with differential coronary event reduction from statin therapy in four randomized controlled trials; this SNP (rs20455) is also associated with the risk for coronary heart disease (CHD) in multiple prospective studies. We investigated whether other common SNPs in the KIF6 region were associated with event reduction from statin therapy. Of the 170 SNPs in the KIF6 region investigated in the Cholesterol and Recurrent Events trial (CARE), 28 were associated with differential event reduction from statin therapy (P (interaction) < 01 in Caucasians, adjusted for age and sex) and were further investigated in the Pravastatin or Atorvastatin Evaluation and Infection Therapy-Thrombolysis In Myocardial Infarction 22 (PROVE IT-TIMI22) and West of Scotland Coronary Prevention Study (WOSCOPS). These analyses revealed that two SNPs (rs9462535 and rs9471077), in addition to rs20455, were associated with event reduction from statin therapy (P (interaction) < 0.1 in each of the three studies). The relative risk reduction ranged from 37 to 50% (P < 0.01) in carriers of the minor alleles of these SNPs and from -4 to 13% (P > 0.4) in non-carriers. These three SNPs are in high linkage disequilibrium with one another (r (2) > 0.84). Functional studies of these variants may help to understand the role of KIF6 in the pathogenesis of CHD and differential response to statin therapy.     

拟干酪乳杆菌发酵L-乳酸合成培养基的优化

为开发一种适合于乳酸发酵过程代谢流分析(MFA)的合成培养基,以拟干酪乳杆菌Lactobacillus paracasei为对象,考察主要营养成分对其生长和乳酸合成的影响.在合成培养基的优化过程中,先确定了影响菌体生长和乳酸合成的主要营养物质及其浓度范围,针对葡萄糖、混合氛基酸、核苷类物质、维生素等生长因子、混合磷源、CaCO3六大类营养成分,使用正交试验法先后设计了六因素五水平和四因素三水平正交试验以及氨基酸梯度试验和氨基酸缺失试验,得到了最佳培养基组成(1L):葡萄糖80g、醋酸钠2g、吐温-80 1 mL、柠檬酸氢二铵1g、金属离子0.72g、混合氨基酸3.925g、核苷类物质0.15g、维生素等生长因子0.075g、混合磷源0g、CaC03 35g.以半合成培养基为对照,考察优化后的合成培养基对菌体生长和乳酸合成的影响.结果表明,菌体在合成培养基中的乳酸产量、产率均比半合成培养基中高.这些结果为L.paracasei的代谢流定量研究莫定了基础.     

Cucurbitacin B induces rapid depletion of the G-actin pool through reactive oxygen species-dependent actin aggregation in melanoma cells

Cucurbitacin B (CuB), a triterpenoid compound isolated from Cucurbitaceae plants, has been reported as a promising anti-cancer agent, yet its action mechanism is still controversial. In this study, we explored the potential mechanism of CuB in murine B16F10 melanoma cells. Anti-proliferation and anti-invasion effects were assessed in cultured cells, and in vivo anti-tumor activity was evaluated in a murine subcutaneous melanoma model. Flow cytometry was adopted to analyze cell cycle distribution and reactive oxygen species (ROS) levels. Actin levels were determined by western blot analysis, and the profiles of differential expressed proteins were identified by a quantitative proteomic approach. The results showed that CuB exerted inhibitory effects on cell proliferation, colony formation, as well as migration and invasion potential of the melanoma cells. The growth of subcutaneous melanoma was significantly inhibited in mice treated with CuB when compared with control group. Furthermore, CuB treatment caused rapid cell membrane blebbing and deformation, and induced G(2)/M-phase arrest and formation of multiploid cells. Notably, the G-actin pool was rapidly depleted and actin aggregates were formed quickly after CuB treatment. A number of cytoskeleton-regulatory proteins were differentially regulated. Blockage of ROS production significantly reduced the G-actin depletion ability and the anti-tumor activity of CuB. These findings indicate that CuB induces rapid depletion of the G-actin pool through ROS-dependent actin aggregation in melanoma cells, which may at least partly account for its anti-tumor activity.     

Chemical constituents and bioactivities of starfish

Starfish have been the research topic in many chemical and pharmacological laboratories due to their complex secondary metabolites and diverse bioactivities. The aim of this review is to provide an up-to-date review on the chemistry and bioactivity of compounds isolated from all kinds of starfish to illustrate the chemodiversity and biological significance of these constituents, along with their geographical distribution where it is discernible.     

Valproic acid synergistically enhances the cytotoxicity of gossypol in DU145 prostate cancer cells: an iTRTAQ-based quantitative proteomic analysis

Gossypol (GOS), a BH3 mimetic, has been investigated as a sensitizing co-therapy to radiation and chemotherapy in treatment of metastatic prostate cancer. In this study, we found that valproic acid (VPA), a histone deacetylase inhibitor (HDACI), counteracted the suppressive effect of GOS on histone H3 acetylation and enhanced the cytotoxicity of GOS to DU145 prostate cancer cells. Significant synergistic effects were observed in combined GOS and VPA treatment, culminating in more DNA damage and cell death. The iTRAQ-based quantitative proteomic analysis revealed differential proteomic profiles in cells treated with VPA, GOS or their combination. In GOS-treated cells, oxidative phosphorylation-related proteins were depressed and endoplasmic reticulum stress markers were upregulated. In the presence of VPA, the GOS-induced mitochondrial stress was further enhanced since glycolysis- and hypoxia-associated proteins were upregulated, suggesting a disruption of energy metabolism in these cells. Furthermore, the DNA damage repair ability of cells co-treated with GOS and VPA was also decreased, as evidenced by the downregulation of DNA damage repair proteins and the enhancement of DNA fragmentation and cell death. These findings suggest that GOS in combination with an HDACI has the potential to increase its clinical efficacy in the treatment of prostate cancer.     

The interaction between the first transmembrane domain and the thumb of ASIC1a is critical for its N-glycosylation and trafficking

Acid-sensing ion channel-1a (ASIC1a), the primary proton receptor in the brain, contributes to multiple diseases including stroke, epilepsy and multiple sclerosis. Thus, a better understanding of its biogenesis will provide important insights into the regulation of ASIC1a in diseases. Interestingly, ASIC1a contains a large, yet well organized ectodomain, which suggests the hypothesis that correct formation of domain-domain interactions at the extracellular side is a key regulatory step for ASIC1a maturation and trafficking. We tested this hypothesis here by focusing on the interaction between the first transmembrane domain (TM1) and the thumb of ASIC1a, an interaction known to be critical in channel gating. We mutated Tyr71 and Trp287, two key residues involved in the TM1-thumb interaction in mouse ASIC1a, and found that both Y71G and W287G decreased synaptic targeting and surface expression of ASIC1a. These defects were likely due to altered folding; both mutants showed increased resistance to tryptic cleavage, suggesting a change in conformation. Moreover, both mutants lacked the maturation of N-linked glycans through mid to late Golgi. These data suggest that disrupting the interaction between TM1 and thumb alters ASIC1a folding, impedes its glycosylation and reduces its trafficking. Moreover, reducing the culture temperature, an approach commonly used to facilitate protein folding, increased ASIC1a glycosylation, surface expression, current density and slowed the rate of desensitization. These results suggest that correct folding of extracellular ectodomain plays a critical role in ASIC1a biogenesis and function.     

Persistence of past stimulations: storing sounds within the inner ear

Tones cause vibrations within the hearing organ. Conventionally, these vibrations are thought to reflect the input and therefore end with the stimulus. However, previous recordings of otoacoustic emissions and cochlear microphonic potentials suggest that the organ of Corti does continue to move after the end of a tone. These after-vibrations are characterized here through recordings of basilar membrane motion and hair cell extracellular receptor potentials in living anesthetized guinea pigs. We show that after-vibrations depend on the level and frequency of the stimulus, as well as on the sensitivity of the ear. Even a minor loss of hearing sensitivity caused a sharp reduction in after-vibration amplitude and duration. Mathematical models suggest that after-vibrations are driven by energy added into organ of Corti motion after the end of an acoustic stimulus. The possible importance of after-vibrations for psychophysical phenomena such as forward masking and gap detection are discussed.     

Isolation of the Chinese rose sHSP gene promoter and its differential regulation analysis in transgenic Arabidopsis plants

In our previous study, we identified a Rosa chinensis heat shock protein (HSP) gene, RcHSP17.8, which was induced by abiotic stresses, such as high temperature and osmotic stress. To analyze the expression of RcHSP17.8 and the function of cis-acting elements in the promoter region, a 1,910 bp fragment of the upstream sequence of the RcHSP17.8 translation initiation codon and five promoter deletion fragments were fused to a β-glucuronidase (GUS) report gene. These plasmids were transferred to Arabidopsis thaliana via Agrobacterium. GUS staining was seen in all the organs, especially in the vascular tissues after heat treatment. In transgenic Arabidopsis, GUS expression driven by the full length promoter was significantly higher under heat shock, but no GUS activity was detected under other abiotic stresses. Deletion analysis indicated that the region from −178 to −771 was essential for the promoter’s response to high temperature.