DNA damage and senescence in osteoprogenitors expressing Osx1 may cause their decrease with age

Age‐related bone loss in mice results from a decrease in bone formation and an increase in cortical bone resorption. The former is accounted by a decrease in the number of postmitotic osteoblasts which synthesize the bone matrix and is thought to be the consequence of age‐dependent changes in mesenchymal osteoblast progenitors. However, there are no specific markers for these progenitors, and conclusions rely on results from in vitro cultures of mixed cell populations. Moreover, the culprits of such changes remain unknown. Here, we have used Osx1‐Cre;TdRFP mice in which osteoprogenitors express the TdRFP fluorescent protein. We report that the number of TdRFP‐Osx1 cells, freshly isolated from the bone marrow, declines by more than 50% between 6 and 24 months of age in both female and male mice. Moreover, TdRFP‐Osx1 cells from old mice exhibited markers of DNA damage and senescence, such as γH2AX foci, G1 cell cycle arrest, phosphorylation of p53, increased p21^CIP1 levels, as well as increased levels of GATA4 and activation of NF‐κB – two major stimulators of the senescence‐associated secretory phenotype (SASP). Bone marrow stromal cells from old mice also exhibited elevated expression of SASP genes, including several pro‐osteoclastogenic cytokines, and increased capacity to support osteoclast formation. These changes were greatly attenuated by the senolytic drug ABT263. Together, these findings suggest that the decline in bone mass with age is the result of intrinsic defects in osteoprogenitor cells, leading to decreased osteoblast numbers and increased support of osteoclast formation.     

Down-regulated expression of aquaporin-4 in the cerebellum after status epilepticus

Status epilepticus (SE) is a common neurological condition associated with high rates of mortality and permanent brain injury. SE usually leads to neuronal death which may be accompanied by edema, epileptogenesis and learning impairment. Aquaporin-4 (AQP4), is a transmembrane water channel protein in the neuropil of the central nervous system that has an important role in water transport in the brain; AQP4 expression is altered in many pathological conditions such as changes in the blood- brain barrier and/or astrocytic activation, including seizures. AQP4 was shown to be downregulated in the piriform cortex and the hippocampus after SE. Although it is normally expressed at a high level in the cerebellum, little is known about AQP4 levels in the cerebellum following SE. We addressed this in the present study in a mouse model of pilocarpine-induced SE. We found that AQP4 expression was reduced from 3 h to 3 days after SE, with the levels recovering on day 7. Moreover, mice in the acute post-SE stages exhibited impaired motor coordination and learning. These results indicate that cerebellar damage following SE involves changes in AQP4 expression.     

Characterization of one novel cry8 gene from Bacillus thuringiensis strain Q52-7

Bacillus thuringiensis (Bt) is the most widely used insecticidal microbe due to its specific toxicity and safe use with respect to animals and the environment. In this study, we isolated Bt strain Q52-7 from a soil sample collected in the Qian Shan District, Liao Ning Province, China. We observed that the Q52-7 strain produced spherical crystals. The Bt Q52-7 strain had high toxicity against Asian Cockchafer (Holotrichia parallela), exhibiting an LC₅₀ of 3.80 × 10⁹ cfu/g, but is not toxic for Anomala corpulenta Motschulsky and Holotrichia oblita. Using general cry8 primers, we amplified a 1.3 kb fragment with the polymerase chain reaction. Specific primers were designed for the amplified fragment to clone the full-length coding region. A novel gene, cry8Na1, had 69 % sequence similarity with cry8Ca1. cry8Na1 gene was successfully expressed in the HD-73^– acrystalliferous mutant of Bt subsp. Kurstaki HD-73. Bioassays demonstrated that the Cry8Na1 protein is highly toxic for the H. parallela, with a 50 % lethal concentration of 8.18 × 10¹⁰ colony forming units per gram.     

Improvement of sludge digestate biodegradability by thermophilic bioaugmentation

The sludge digestate stabilized by mesophilic anaerobic digestion was further degraded through thermophilic anaerobic digestion using 0–10 % (v/v) of thermophilic, proteolytic Coprothermobacter proteolyticus, and/or methanogenic granular sludge. The results demonstrated that the temperature shift to thermophilic condition promoted abiotic solubilization of proteins and reactivated the fermentative bacteria and methanogens indigenous in the sludge digestate, resulting in a final methane yield of 6.25 mmol-CH₄/g-volatile suspended solid (VSS) digestate. The addition of C. proteolyticus accelerated the hydrolysis and fermentation of proteins and polysaccharides in the digestate during the early stage of thermophilic anaerobic digestion and stimulated methane production by syntrophic cooperation with methanogenic granular sludge. In the treatment with granular sludge and inoculated with 10 % (v/v) of C. proteolyticus, a final methane yield of 7 mmol-CH₄/g-VSS digestate was obtained, and 48.4 % proteins and 27.0 % polysaccharides were degraded. The dissolved proteins were contributed by abiotic factor, C. proteolyticus, and indigenous digestate bacteria, respectively, by around 16, 28, and 56 %.     

Ten polymorphic microsatellite loci for the Atlantic halibut (Hippoglossus hippoglossus) and cross-species application in related species

In the present study, 10 polymorphic microsatellite DNA loci from Atlantic halibut (Hippoglossus hippoglossus) were isolated and characterized. The number of alleles for these loci ranged from 2 to 4 in tested 24 individuals. Observed and expected heterozygosities per locus varied from 0.21 to 0.70 and from 0.31 to 0.65, respectively. Most of these 10 microsatellite loci were successfully amplified and showed polymorphic in five related species. These loci will be useful for the assessment of genetic diversity and population structure of Atlantic halibut. H. Ding and C. Shao contributed equally to this work.     

Genome Sequence of Pseudomonas mendocina DLHK,Isolated from a Biotrickling Reactor

Pseudomonas mendocina DLHK is an aerobic bacterium isolated from a biotrickling reactor which can remove nitric oxide, a common air pollutant from combustion exhaust gas. Here, we present the draft genome of Pseudomonas mendocina DLHK.     

Reorienting the Fab Domains of Trastuzumab Results in Potent HER2 Activators

The structure of the Fab region of antibodies is critical to their function. By introducing single cysteine substitutions into various positions of the heavy and light chains of the Fab region of trastuzumab, a potent antagonist of HER2, and using thiol chemistry to link the different Fabs together, we produced a variety of monospecific F(ab′)₂-like molecules with activities spanning from activation to inhibition of breast tumor cell growth. These isomers (or bis-Fabs) of trastuzumab, with varying relative spatial arrangements between the Fv-regions, were able to either promote or inhibit cell-signaling activities through the PI3K/AKT and MAPK pathways. A quantitative phosphorylation mapping of HER2 indicated that the agonistic isomers produced a distinct phosphorylation pattern associated with activation. This study suggests that antibody geometric isomers, found both in nature and during synthetic antibody development, can have profoundly different biological activities independent of their affinities for their target molecules.     

Development of polymorphic microsatellite markers from barfin flounder (Verasper moseri) and their cross-species amplification

Barfin flounder (Verasper moseri) is a rare fish species in the world. Here, we reported 10 polymorphic microsatellite loci isolated from a dinucleotide-enriched genomic library of barfin flounder (Verasper moseri). The number of alleles, observed, and expected heterozygosity per locus in a test population ranged from 2 to 6, from 0.3333 to 1.0000, and from 0.4866 to 0.7774, respectively. One locus significantly deviated from Hardy–Weinberg equilibrium after Bonferroni correction and no significant linkage disequilibrium was found between pairs of loci. Cross-species amplification of these microsatellite loci in additional five fish species was performed. These polymorphic microsatellite loci would be useful for investigating genetic population structure and construction of genetic linkage map in Verasper moseri. Gui-Dong Miao and Chang-Wei Shao Contributed equally to this work.     

Endogenous hormonal and enzymatic responses of Catharanthus roseus with triadimefon application under water deficits

The effect of triadimefon was investigated in a medicinal plant, Catharanthus roseus subjected to water deficit stress. The abscisic acid (ABA) level, DNA and RNA contents and activities of ATPase and protease were found varying in different parts of the plants under treatment. Drought treatment increased the ABA level more than twofold in all parts of the plants. TDM treatment to the drought stressed plants showed highest contents. In roots, stem and leaves, drought stress caused a decrease in the DNA and RNA contents when compared with control and other treatments. TDM treatment with drought increased the nucleic acid contents to the level of the control roots. The activity of ATPase and protease were increased under drought treatment and lowered due to TDM applications. This information could be useful in the field of soil water deficits reclamation efforts by using plant growth regulators.     

重组大肠杆菌热稳定性过氧化氢酶的纯化及性质研究

将产热稳定性过氧化氢酶的重组大肠杆菌培养后菌体破碎得到的粗酶液经热处理、硫酸铵分级沉淀、DEAE\|Sephadex A\|50离子交换层析、HiPrep16/10 Phenyl疏水作用层析、Superdex200 HR 10/30凝胶层析提纯后得到电泳纯的酶,比酶活达到15629U/mg。此酶的最适温度为70℃,最适pH70,在60℃保温60min酶活力基本不变,在pH3～8的范围内比较稳定。此酶的Km和Vmax分别为775mmol/L和278mmol\5min\+\{-1\}·mg-1。1mmol/L的Zn2+、Ba2+、Mn2+可使该酶完全失活,KCN、NaN\-3、Na\-2S\-2O\-4、巯基乙醇对酶活力有抑制作用,50mmol/L的EDTA不影响酶活性。