Preparation, characterization and pH-metric measurements of 4-hydroxysalicylidenechitosan Schiff-base complexes of Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ru(III), Rh(III), Pd(II) and Au(III)

The 4-hydroxysalicylidenechitosan Schiff-base (2CS-Hdhba) was prepared by the condensation of 2,4-dihydroxybenzaldehyde with chitosan, and its metal complexes, [M(2CS-dhba)Cl₂(H₂O)₂] (M(III) = Fe, Ru, Rh), [M′(2CS-dhba)(AcO)(H₂O)₂] (M′(II) = Co, Ni, Cu, Zn), [Pd(2CS-dhba)Cl(H₂O)] and [Au(2CS-dhba)Cl₂], are reported. These complexes were characterized by elemental analysis, by spectral data (FTIR, solid-phase ¹³C NMR, UV–vis and ESR spectroscopy), by morphological observations (SEM and XRD), and by magnetic and thermal measurements. The Schiff base (2CS-Hdhba) behaves as a bidentate chelate with a single negative charge. The azomethine nitrogen and the deprotonated 2-hydroxy centres with the pendant glucosamine hydroxy functionality play no role in coordination. The dissociation constants of 2CS-Hdhba and the stability constants of some of its metal complexes have been determined pH-metrically.     

Localization of rRNA genes in the nuclear space of Calliphora erythrocephala Mg. nurse cells during polytenization

Multicolor 3D fluorescence in situ hybridization was used to study arrangement of rRNA genes in Calliphora erythrocephala nurse cell nuclei with different levels of polyteny. It has been shown that the rRNA genes are exclusively localized to chromosome 6, suggesting that chromosome 6 is the only C. erythrocephala chromosome responsible for nucleolar formation. We have also described changes in localization of ribosomal genes within the chromosome territory during polytenization, namely, that rDNA signals are detected in the peripheral region of chromosome territory starting from the stage of polytene chromosomes. In addition, it has emerged that large nucleolus associated with chromosome 6 starts to develop in the central nuclear region in the C. erythrocephala nurse cell nuclei at the stage of a primary reticular structure. The central position and nucleolar structure are retained at the stages when chromosome 6 occupies the central position, that is, at the stages of polytene and bloblike chromosomes. When the nucleus restores a reticular structure but at a higher polyteny level, the displacement of chromosome 6 to the nuclear periphery is accompanied by disruption of the large nucleolus into micronucleoli. The micronucleoli are distributed in the nuclear space retaining their association with the nucleolar-organizing regions of chromosome 6. Thus, our data suggest that the large-scale alterations in the organization of chromosome 6 and the nucleolus during polytenization are the correlated processes directly dependent on the rRNA gene activity. The earlier described dynamics of nucleolar-organizing chromosome territory and nucleolus in the nuclear space is likely to be associated with the change in the total expression activity of the nucleus, which complies with the hypothesis on the correlation between spatial nuclear organization and expression regulation of genetic material.     

Pulmonary Toxicity in Mice Following Exposure to Cerium Chloride

The widespread application of lanthanoids (Lns) in manufacturing industries has raised occupational and environmental health concerns about the possible increased health risks to humans exposed to Lns in their working and living environments. Numerous studies have shown that exposures to Ln cause pulmonary injury in animals, but very little is known about the molecular mechanisms of the pulmonary inflammation caused by cerium chloride (CeCl₃) exposure. In this study, we evaluated the oxidative stress and molecular mechanism underlying with the pulmonary inflammation associated with chronic lung toxicity in mice treated with nasally instilled CeCl₃ for 90 consecutive days. Our findings suggest that significant cerium accumulated in the lung, leading the obvious increase of the lung indices, significant increases in inflammatory cells and levels of lactate dehydrogenase, alkaline phosphate, and total protein, overproduction of reactive oxygen species and peroxidation of lipids, reduced antioxidant capacity, and pulmonary inflammation. CeCl₃ exposure also activated nuclear factor κB, increased the expression of tumor necrosis factor α, cyclooxygenase-2, heme oxygenase 1, interleukin 2, interleukin 4, interleukin 6, interleukin 8, interleukin 10, interleukin 18, interleukin 1β, and CYP1A1. However, CeCl₃ reduced the expression of nuclear factor κB (NF-κB)-inhibiting factor and heat shock protein 70. These findings suggest that the pulmonary inflammation caused by CeCl₃ in mice is closely associated with oxidative stress and inflammatory cytokine expression.     

miR-208-Induced Epithelial to Mesenchymal Transition of Pancreatic Cancer Cells Promotes Cell Metastasis and Invasion

The aim of this study was to investigate the role of miR-208 in the invasion and metastasis of pancreatic cancer cells and the underlying molecular mechanism. miR-208 mimic, miR-208 inhibitor and NC were transfected into pancreatic cancer cell line Bxpc3 using liposome. Transwell invasion and scratch assays were used to test cell migratory and invasive abilities. Western blotting and quantitative PCR methods were used to detect E-cadherin, fibronectin and vimentin protein and mRNA expression in pancreatic cancer cell line BxPC3 after transfection by miR-208 mimic, miR-208 inhibitor and NC. Transwell invasion and scratch assays showed that after overexpressing miR-208, pancreatic cancer cell line BxPC3 exhibited enhanced in vitro migratory and invasive abilities, while after downregulating miR-208 expression, cell migratory and invasive abilities were decreased. Western blotting and quantitative PCR showed that after overexpressing miR-208, expression of E-cadherin, an epithelial cell marker, was decreased and expression of fibronectin and vimentin, interstitial cell markers, was increased in pancreatic cancer cell line BxPC3; however, after inhibiting miR-208, increased E-cadherin expression and decreased fibronectin and vimentin expression were observed in pancreatic cancer cell line BxPC3. After overexpressing miR-208, p-AKT and p-GSK-3β expression was altered by activating AKT/GSK-3β/snail signaling pathway. miR-208 induces epithelial to mesenchymal transition of pancreatic cancer cell line BxPC3 by activating AKT/GSK-3β/snail signaling pathway and thereby promotes cell metastasis and invasion.     

黑龙江呼兰河口湿地自然保护区夏季鸟类群落结构及多样性

2011年至2013年每年的5—8月,采用样线法对黑龙江呼兰河口湿地自然保护区夏季鸟类的群落组成与结构进行了研究。野外调查共记录鸟类13目33科91种,其中国家重点保护鸟类11种。区内夏季鸟类以非雀形目鸟类居多,共有18科53种,占总种数的58%;雀形目鸟类15科38种,占总种数的42%。从居留型来看,保护区夏季鸟类群落中留鸟16种,夏候鸟75种。在地理区系构成上,保护区以古北界物种为主,共有47种,占总种数的51.6%,其次是广布种,共有41种,占45.1%,东洋界物种仅有3种。连续3年的多样性指数呈下降趋势,推测人为活动干扰增加与河口湿地公园建设可能是导致鸟类数量减少的最主要因素。     

Detecting the selection signatures in Chinese Duroc,Landrace, Yorkshire,Liangshan, and Qingyu pigs

Functional & Integrative Genomics - Here we used two kinds of chips data from 5 pig breeds, Chinese Duroc (DD), Landrace (LL), Yorkshire (YY), Liangshan (LS), and Qingyu pigs (QY) in China to...     

Diazoxide-induced cardioprotection via DeltaPsim loss depending on timing of application

Although the role of mitochondrial ATP-sensitive potassium (mitoKATP) channels in cardioprotection is widely accepted, it remains unclear when their opening is critical for protection. We tested the hypothesis that the mitoKATP channel acts as a trigger or mediator of protection against apoptosis through loss of mitochondrial inner membrane potential (DeltaPsim). Exposure of neonatal rat cardiomyocytes to H2O2 (0.5 mmol/L) resulted in apoptosis associated with severe DeltaPsim loss. Pretreatment with diazoxide (20 to 100 micromol/L) prevented H2O2-induced apoptosis and DeltaPsim loss at 2 but not 18 h after exposure, while the latter was prevented by cotreatment with diazoxide. Lack of protection by pretreatment with diazoxide was observed in cardiomyocytes cultured in a medium containing H2O2 for 2 h and then not containing for 16 h. The slopes of the regression lines of the relationship between the proportion of apoptotic cells and DeltaPsim loss (y = -0.89 vs. -0.42) and the proportion of cells with high side scatter signal differed between cardiomyocytes exposed H2O2 for 2 and 18 h. Diazoxide per se caused a transient DeltaPsim loss (within 30 min) with a recovery followed by persistent DeltaPsim loss (after 6 h). Inhibition of the former by 5-hydroxydecanoate (5-HD, 0.5 mmol/L) abolished protection of pretreatment with diazoxide (trigger phase), while that of the latter prevented the protection of cotreatment with diazoxide (mediator phase). Our results suggest that mitoKATP channels act as a trigger and mediator of cardioprotection through a transient or persistent DeltaPsim loss depending on phenotypic consequence in response to oxidants.     

Self-Assembly in Monoelaidin Aqueous Dispersions: Direct Vesicles to Cubosomes Transition

Background

In the present study, synchrotron small-angle X-ray scattering (SAXS) and Cryo-TEM were used to characterize the temperature-induced structural transitions of monoelaidin (ME) aqueous dispersion in the presence of the polymeric stabilizer F127. We prove that the direct transition from vesicles to cubosomes by heating this dispersion is possible. The obtained results were compared with the fully hydrated bulk ME phase.

Methodology/Principal Findings

Our results indicate the formation of ME dispersion, which is less stable than that based on the congener monoolein (MO). In addition, the temperature-dependence behavior significantly differs from the fully hydrated bulk phase. SAXS findings indicate a direct L_α-V₂ internal transition in the dispersion. While the transition temperature is conserved in the dispersion, the formed cubosomes with internal Im3m symmetry clearly contain more water and this ordered interior is retained over a wider temperature range as compared to its fully hydrated bulk system. At 25°C, Cryo-TEM observations reveal the formation of most likely closely packed onion-like vesicles. Above the lamellar to non-lamellar phase transition at 65°C, flattened cubosomes with an internal nanostructure are observed. However, they have only arbitrary shapes and thus, their morphology is significantly different from that of the well-shaped analogous MO cubosome and hexosome particles.

Conclusions/Significance

Our study reveals a direct liposomes-cubosomes transition in ME dispersion. The obtained results suggest that the polymeric stabilizer F127 especially plays a significant role in the membrane fusion processes. F127 incorporates in considerable amount into the internal nanostructure and leads to the formation of a highly swollen Im3m phase.