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Background: Research has shown that epigenetic modification are involved the regulation of diapause in bivoltine silkworms (Bombyx mori), but it remains unclear how epigenetic modification in response to environmental signals precisely to regulate the diapause processing of bivoltine B. mori. Methods and results: In this study, the diapause terminated eggs of bivoltine B. mori, Qiufeng (QF) were divided into two groups: a QFHT group incubated at 25 °C with a natural day/night cycle to produce diapause eggs, and a QFLT group incubated at 16.5 °C in darkness to produce non-diapause eggs. On the 3rd day of the pupal stage, the total RNAs of the eggs were extracted and their N6-adenosine methylation (m6A) abundances were analyzed to explore the effects of m6A methylation on diapause in the silkworm. The results showed that 1984 m6A peaks are shared, 1563 in QFLT and 659 in QFHT. The m6A methylation level of the QFLT group was higher than that of the QFHT one in various signaling pathways. The m6A methylation rate of mevalonate kinase (MK) in the insect hormone synthesis pathway was significantly different between the two groups. The knockdown of MK by RNA interference in the pupae of QFLT resulted in females laying diapause eggs rather than non-diapause eggs after mating. Conclusions: m6A methylation involves in the diapause regulation of bivoltine B. mori by changing the expression levels of MK. This result provides a clearer image of the environmental signals on the regulation of diapause in bivoltine silkworms. [ABSTRACT FROM AUTHOR]

Background: As a potential tumor suppressor gene, Claudin-7 (Cldn7), which is a component of tight junctions, may play an important role in colorectal cancer occurrence and development.Aims: To generate a knockout mouse model of inducible conditional Cldn7 in the intestine and analyze the phenotype of the mice after induction with tamoxifen.Methods: We constructed Cldn7-flox transgenic mice and crossed them with Villin-CreERT2 mice. The Cldn7 inducible conditional knockout mice appeared normal and were well developed at birth. We induced Cldn7 gene deletion by injecting different dosages of tamoxifen into the mice and then conducted a further phenotypic analysis.Results: After induction for 5 days in succession at a dose of 200 µl tamoxifen in sunflower oil at 10 mg/ml per mouse every time, the mice appeared dehydrated, had a lower temperature, and displayed inactivity or death. The results of hematoxylin-eosin staining showed that the intestines of the Cldn7 inducible conditional knockout mice had severe intestinal defects that included epithelial cell sloughing, necrosis, inflammation and hyperplasia. Owing to the death of ICKO mice, we adjusted the dose of tamoxifen to a dose of 100 µl in sunflower oil at 10 mg/ml per mouse (aged more than 8 weeks old) every 4 days. And we could induce atypical hyperplasia and adenoma in the intestine. Immunofluorescent staining indicated that the intestinal epithelial structure was destroyed. Electron microscopy experimental analysis indicated that the intercellular gap along the basolateral membrane of Cldn7 inducible conditional knockout mice in the intestine was increased and that contact between the cells and matrix was loosened.Conclusions: We generated a model of intestinal Cldn7 inducible conditional knockout mice. Intestinal Cldn7 deletion induced by tamoxifen initiated inflammation and hyperplasia in mice. [ABSTRACT FROM AUTHOR]

Some genes involved in complex human diseases are particularly vulnerable to genetic variations such as single nucleotide polymorphism, copy number variations, and mutations. For example, Ras mutations account for over 30 % of all human cancers. Additionally, there are some genes that can display different variations with functional impact in different diseases that are unrelated. One such gene stands out: δ-catenin/NPRAP/Neurojungin with gene designation as CTNND2 on chromosome 5p15.2. Recent advances in genome wide association as well as molecular biology approaches have uncovered striking involvement of δ- catenin gene variations linked to complex human disorders. These disorders include cancer, bipolar disorder, schizophrenia, autism, Cri-du-chat syndrome, myopia, cortical cataract-linked Alzheimer's disease, and infectious diseases. This list has rapidly grown longer in recent years, underscoring the pivotal roles of δ- catenin in critical human diseases. δ-Catenin is an adhesive junction-associated protein in the delta subfamily of the β-catenin superfamily. δ-Catenin functions in Wnt signaling to regulate gene expression and modulate Rho GTPases of the Ras superfamily in cytoskeletal reorganization. δ-Catenin likely lies where Wnt signaling meets Rho GTPases and is a unique and vulnerable common target for mutagenesis in different human diseases. [ABSTRACT FROM AUTHOR]

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A chemical study of the 80% aqueous acetone extract of aerial parts of Setaria viridis led to the isolation of three new naphthol rhamnosides, 8-O-α-L-rhamnosyl-β-sorigenin ( 1), 6-hydroxy-8-O-α-L-rhamnosyl-β-sorigenin ( 2), and 6-methoxy-8-O-α-L-rhamnosyl-β-sorigenin ( 3), together with nine ( 4-12) known compounds. Their structures were established on the basis of spectroscopic data, including IR, MS, 1D, and 2D NMR. All the 12 compounds were tested for their antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, as well as antimicrobial activity. Compounds 1-3 exhibited strong antioxidant activity with IC values of 10.5, 13.8, and 15.3 μM, respectively, and modest activity against Staphylococcus aureus (ATCC 29213). [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the mechanism of deposition of extracellular matrix induced by TGF-β1 in skeletal muscle-derived stem cells (MDSCs). Rat skeletal MDSCs were obtained by using preplate technique, and divided into four groups: group A (control group), group B (treated with TGF-β1, 10 ng/mL), group C (treated with TGF-β1 and anti-connective tissue growth factor (CTGF), both in 10 ng/mL), and group D (treated with anti-CTGF, 10 ng/mL). The expression of CTGF, collagen type-I (COL-I) and collagen type-III (COL-III) in MDSCs was examined by using RT-PCR, Western blot and immunofluorescent stain. It was found that one day after TGF-β1 treatment, the expression of CTGF, COL-I and COL-III was increased dramatically. CTGF expression reached the peak on the day 2, and then decreased rapidly to a level of control group on the day 5. COL-I and COL-III mRNA levels were overexpresed on the day 2 and 3 respectively, while their protein expression levels were up-regulated on the day 2 and reached the peak on the day 7. In group C, anti-CTGF could partly suppress the overexpression of COL-I and COL-II induced by TGF-β1 one day after adding CTGF antibody. It was concluded that TGF-β1 could induce MDSCs to express CTGF, and promote the production of COL-I and COL-III. In contrast, CTGF antibody could partially inhibit the effect of TGF-β1 on the MDSCs by reducing the expression of COL-I and COL-III. Taken together, we demonstrated that TGF-β1-CTGF signaling played a crucial role in MDSCs synthesizing collagen proteins in vitro, which provided theoretical basis for exploring the methods postponing skeletal muscle fibrosis after nerve injury. [ABSTRACT FROM AUTHOR]

Long distance buried liquid-conveying pipeline is inevitable to cross faults and under earthquake action, it is necessary to calculate fluid-structure interaction(FSI) in finite element analysis under pipe-soil interaction. Under multi-action of site, fault movement and earthquake, finite element model of buried liquid-conveying pipeline for the calculation of fluid structure interaction was constructed through combinative application of ADINA-parasolid and ADINA-native modeling methods, and the direct computing method of two-way fluid-structure coupling was introduced. The methods of solid and fluid modeling were analyzed, pipe-soil friction was defined in solid model, and special flow assumption and fluid structure interface condition were defined in fluid model. Earthquake load, gravity and displacement of fault movement were applied, also model preferences. Finite element research on the damage of buried liquid-conveying pipeline was carried out through computing fluid-structure coupling. The influences of pipe-soil friction coefficient, fault-pipe angle, and liquid density on axial stress of pipeline were analyzed, and optimum parameters were proposed for the protection of buried liquid-conveying pipeline. [ABSTRACT FROM AUTHOR]

Based on the distribution of underground fracture and faults in Lunnan area, the distribution of underground liquid was investigated. According to the well data of petroleum exploration in Lunnan area, the influencing factors of fracture distribution was analyzed. Model preferences were studied and all influencing factors were considered, such as depth, temperature, confining pressure, reconstruction in tectonic movement, and randomicity. Fracture probability was obtained through numerical simulation of stress field, and the relationship between fracture distribution and liquid distribution was analyzed. According to the calculating results, liquid distribution was predicted, and liquid movement was analyzed through geological analysis. By comparing liquid distribution with the results of liquid test in wells, it is found that liquid moves through faults and accumulates to fracture areas. Faults are channel-ways of liquid movement and high fracture probability areas near faults are favorite areas for liquid accumulation. Because Lunnan area is a typical area for liquid movement research in carbonate rock areas with complicated influencing factors and four fracture types, this method can be applied to other carbonate rock areas, especially, those with violent faults activity and complicated fracture distribution. Finally, some advice is proposed for liquid movement investigation in carbonate rock area. [ABSTRACT FROM AUTHOR]

It was shown that active queue management schemes implemented in the routers of communication networks supporting transmission control protocol (TCP) flows can be modelled as a feedback control system. In this paper based on Lyapunov function we developed an optimal controller to improve active queue management (AQM) router’s stability and response time, which are often in conflict with each other in system performance. Ns-2 simulations showed that optimal controller outperforms PI controller significantly. [ABSTRACT FROM AUTHOR]

We have investigated the effects of temperature on the conductance and voltage-dependent kinetics of cardiac gap junction channels between pairs of seven-day embryonic chick ventricle myocytes over the range of 14-26 degrees C. Records of junctional conductance (Gj) and steady-state unit junctional channel activity were made using the whole-cell double patch-clamp technique while the bath temperature was steadily changed at a rate of about 4 degrees C/min. The decrease in Gj upon cooling was biphasic with a distinct break at 21 degrees C. In 12 cell pairs, Q10 was 2.2 from 26 to 21 degrees C, while between 21 and 14 degrees C it was 6.5. The mean Gj at 22 degrees C (Gj22) was 3.0 +/- 2.1 nS, ranging in different preparations from 0.24 to 6.4 nS. At room temperature, embryonic cardiac gap junctions contain channels with conductance states near 240, 200, 160, 120, 80 and 40 pS. In the present study, we demonstrate that cooling decreases the frequency of channel openings at all conductance levels, and at temperatures below 20 degrees C shifts the prevalence of openings from higher to lower conductance states: all 240 pS openings disappear below 20 degrees C; 200 pS openings are suppressed at 17 degrees C; below 16 degrees C 160 and 120 pS events disappear and only 80 and 40 pS states are seen. Temperature also affected the voltage-dependent kinetics of the channels. Application of a 6 sec, 80 mV voltage step across the junction (Vj80) caused a biexponential decay in junctional conductance. Decay was faster at lower temperatures, whereas the rate of recovery of Gj after returning to Vj0 was slowed. Cooling reduced the fast decay time constant, increased both recovery time constants, and decreased the magnitude of Gj decay, thus leaving a 10-16% larger residual conductance (Gss/Ginit, +/- 80 mV Vj) at 18 than at 22 degrees C. From these results we propose that embryonic chick cardiac gap junctions contain at least two classes of channels with different conductances and temperature sensitivities. [ABSTRACT FROM AUTHOR]

We used the double whole-cell voltage-clamp technique on ventricle cell pairs isolated from 7-day chick heart to measure the conductance of their gap junctions ( G) and junctional channels ( γ) with a steady-state voltage difference ( V) applied across the junction. Currents were recorded from single gap junction channels ( i) as symmetrical rectangular signals of equal size and opposite sign in the two cells, and γ was measured from i/ V. We observed channel openings at six reproducible conductance levels with means of 42.6, 80.7, 119.6, 157.7, 200.4 and 240.3 pS. More than half of all openings were to the 80-and 160-pS conductance levels. The probability that a high conductance event (e.g., 160 or 240 pS) results from the random simultaneous opening of several 40-pS channels is small, based on their frequency of occurrence and on the prevalence of shifts between small and large conductance states with no intervening 40-pS steps. Our results are consistent with three models of embryonic cardiac gap junction channel configuration: a homogeneous population of 40-pS channels that can open cooperatively in groups of up to six; a single population of large channels with a maximal conductance near 240 pS and five smaller substates; or several different channel types, each with its own conductance. G was determined from the junctional current ( I) elicited by rectangular pulses of applied transjunctional voltage as I/ V. It was highest near 0 V and was progressively reduced by application of V between 20 and 80 mV or −20 and −80 mV. In response to increases in V, G decayed in a voltage-and timedependent fashion. After a 6-sec holding period at 0 V, the initial conductance ( G) measured immediately after the onset of an 80-mV step in V was nearly the same as that measured by a 10-mV prepulse. However, during 6-sec pulses of V>±20 mV, G declined over several seconds from G to a steady-state value ( G). At potentials greater than ±20 mV the current decay could be fit with biexponential curves with the slow decay time constant ( τ) 5-20 times longer than τ. For the response to a step to 80 mV V, for example, τ=127 msec and τ=2.6 sec. The rate of current decay in response to smaller positive or negative steps in V was slower, the magnitude of the decline was smaller, and the ratio τ/ τ decreased. The relationship between G and V was approximately linear between 0 and 80 mV or −80 mV. whereas the relationship between G and V was nonlinear beyond ±20 mV. Upon returning to 0 V, G recovered with a biexponential time course, reaching its maximal value after several seconds; recovery time constants after a step in V from 80 to 0 mV were 225 msec and 1.9 sec. In the resting state, at low junctional voltage, high conductance channel activity (160-240 pS) is favored. Voltage-dependent decline of G results in part from a shift from high to lower conductance states. [ABSTRACT FROM AUTHOR]