Catalytic properties of inorganic pyrophosphatase in rat liver mitochondria]

Intact rat liver mitochondria possess a very low hydrolytic activity, if any, towards exogenous pyrophosphate. This activity can be unmasked by making mitochondria permeable to PPi by toluene treatment or by disrupting them with detergents or ultrasound, thus indicating that the active site of pyrophosphatase is localized in the matrix. The initial rates of PPi hydrolysis of toluene-permeabilized mitochondria and purified pyrophosphatase were found to depend, in a similar manner, on PPi and Mg2+ concentrations. The simplest model consistent with these data in both cases implies that the reaction proceeds via two pathways and requires MgPPi as substrate and at least one Mg2+ ion as activator. In the presence of 0.4 mM Mg2+ (physiological concentration) the inhibition constant for Ca2+ is 12 microM and the enzyme activity is no less than 50% of the maximal one. The data obtained suggest that the activity of pyrophosphatase in mitochondria is high enough to keep free PPi concentration at a level close to the equilibrium one.     

Effects of amiridin and tacrine, drugs effective in Alzheimer's disease, on the activity of monoamine oxidase A and B]

In vitro comparative studies of effects of amiridin (9-amino-2, 3, 5, 6, 7, 8-hexahydro-1H-cyclopentane (b) choline monohydrate hydrochloride) and tacrine physostigmine and piracetam on monoamine oxidase A (MAO-A) and B (MAO-B) activity in the rat brain were carried out. Piracetam (1 x 10(-4)-1 x 10(-3) M) dose-dependently increased MAO-A and MAO-B activity. At all concentrations used (1 x 10(-7)-5 x 10(-4) M) physostigmine had no effect on MAO-A and MAO-B activity. Amiridin was found to inhibit MAO-B activity at 5 x 10(-4) M concentration only. Tacrine inhibited MAO-A activity at 5 x 10(-4) M concentration. The therapeutical effects of amiridin and tacrine in treatment of Alzheimer disease were not related to their action on MAO-A and -B activity.     

The myoarchitectonics of the human gastric cardia]

Anatomical investigations of the muscular layer of the cardia in corpses of adults (30-70 years of age) have shown the presence in the cardia of a 25-35 mm long sphincter disposed at an angle to the horizontal plane. Its formation proceeds with the participation of both the esophageal musculature (circular layer) and gastric musculature (gastro-esophageal fibers of the oblique muscular layer). As a whole, myo-architectonics of the cardia is dependent on the character of interrelation of the muscular layers of the esophagus and stomach which is responsible for the opening and closure of the gastro-esophageal junction.     

USP15 promotes the apoptosis of degenerative nucleus pulposus cells by suppressing the PI3K/AKT signalling pathway

ObjectivesDegenerative disc disease is characterized by an enhanced breakdown of its existing nucleus pulposus (NP) matrix due to the dysregulation of matrix enzymes and factors. Ubiquitin‐specific protease 15 (USP15) is reported to be abnormal in certain human diseases. However, its role in NP degeneration remains unclear. Therefore, we aimed to explore the function of USP15 in degenerative NP cell specimens.MethodsWe induced gene silencing and overexpression of USP15 in degenerative NP cells using RNA interference (RNAi) and a lentiviral vector, respectively. qRT‐PCR and Western blotting were used to determine gene and protein expression levels. Cell apoptosis was analysed via flow cytometry. Protein interaction was examined by performing a co‐immunoprecipitation assay. Furthermore, the PI3K inhibitor LY294002 and agonist IGF‐1 were used to investigate the link between USP15 and AKT in NP degeneration.ResultsWe found that USP15 was up‐regulated in degenerative NP cells and that its overexpression accelerated the process of apoptosis. Moreover, USP15 expression levels negatively correlated with AKT phosphorylation in degenerative NP cells. Furthermore, targeting and silencing USP15 with miR‐338‐3p and studying its interaction with FK506‐binding protein 5 (FKBP5) revealed enhancement of FKBP5 ubiquitination, indicating that USP15 is a component of the FKBP5/AKT signalling pathway in degenerative NP cells.ConclusionsOur results show that USP15 exacerbates NP degradation by deubiquitinating and stabilizing FKBP5. This in turn results in the suppression of AKT phosphorylation in degenerative NP cells. Therefore, our study provides insights into the understanding of USP15 function as a potential molecule in the network of NP degeneration.     

亏缺灌溉对板蓝根叶片光合生理特性及产量的影响

以北板蓝根(Isatis tinctoria)为研究对象, 于2018年在河西走廊中部干旱绿洲开展水分控制试验, 设轻、中、重度亏水及充分供水4个控水水平, 通过大田试验探究膜下滴灌条件下亏缺灌溉对板蓝根叶片生理指标、灌水量及产量的影响, 为河西地区板蓝根灌溉策略的制定提供理论依据。结果表明, 板蓝根叶片净光合速率(P_n)、蒸腾速率(T_r)和气孔导度(G_s)因营养和肉质根生长期受到亏缺灌溉影响而显著下降, 降幅随亏水程度的加剧而增大, 轻度亏水处理对叶片光合能力的影响不显著, 且在复水之后存在一定的补偿响应; 轻度亏水处理的产量与对照(8 348.91 kg·hm^-2)相比无显著差异, 而其它处理的产量均有不同程度的下降; 灌水量与产量的拟合关系呈二次抛物线, 即产量不随灌水量的增加而升高。因此, 综合分析表明膜下滴灌调亏降低了板蓝根叶片的光合能力, 而营养生长期轻度亏缺灌溉可以节水并提高产量和灌溉效率。     

Polymorphism analysis and supertype definition of swine leukocyte antigen class I molecules in three-way crossbred (Landrace,Duroc, and Yorkshire) pigs: implications for the vaccine development of African swine fever virus

正Dear Editor,Swine major histocompatibility complex (MHC) is a highly polymorphic gene in pigs and is also called swine leukocyte antigen (SLA)(Fan et al., 2018). SLA is divided into three major categories, SLA Ⅰ (SLA-1,-2,-3), SLA Ⅱ, and SLA Ⅲ(Smith et al., 2005). SLA Ⅰ plays an important role in cellular immunity which can eliminate viruses and other foreign     

Esterase activity and interaction of human hemoglobin with diclofenac sodium: A spectroscopic and molecular docking study

To get an idea about the pharmacokinetics and pharmacodynamics, it is important to study the drug‐protein interaction. Therefore, herein, we studied the interaction of diclofenac sodium (DIC) with human hemoglobin. The binding study of nonsteroidal antiinflammatory drug, DIC with human hemoglobin (HHB) was done by utilizing fluorescence, UV–visible, time‐resolved fluorescence and far‐UV circular dichroism spectroscopy (CD). Various thermodynamic parameters such as enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy change (ΔG) were also calculated. CD results showed that DIC induces secondary structure change in HHB. Fluorescence resonance energy transfer was also performed. Additionally, it was also observed that DIC inhibits the esterase‐like enzymatic activity of HHB via competitive inhibition.     

Recognition of RNA by the S9.6 antibody creates pervasive artifacts when imaging RNA:DNA hybrids

The S9.6 antibody is broadly used to detect RNA:DNA hybrids but has significant affinity for double-stranded RNA. The impact of this off-target RNA binding activity has not been thoroughly investigated, especially in the context of immunofluorescence microscopy. We report that S9.6 immunofluorescence signal observed in fixed human cells arises predominantly from ribosomal RNA, not RNA:DNA hybrids. S9.6 staining was unchanged by pretreatment with the RNA:DNA hybrid–specific nuclease RNase H1, despite verification in situ that S9.6 recognized RNA:DNA hybrids and that RNase H1 was active. S9.6 staining was, however, significantly sensitive to RNase T1, which specifically degrades RNA. Additional imaging and biochemical data indicate that the prominent cytoplasmic and nucleolar S9.6 signal primarily derives from ribosomal RNA. Importantly, genome-wide maps obtained by DNA sequencing after S9.6-mediated DNA:RNA immunoprecipitation (DRIP) are RNase H1 sensitive and RNase T1 insensitive. Altogether, these data demonstrate that imaging using S9.6 is subject to pervasive artifacts without pretreatments and controls that mitigate its promiscuous recognition of cellular RNAs.