Thermal manipulation during the middle incubation stage has a repressive effect on the immune organ development of Peking ducklings

Avian embryos are easily influenced by their environment during incubation. Previous studies have demonstrated that incubation temperature changes could influence muscle development and body weight, which subsequently determine the adult phenotype. The objective of this study was to investigate whether the development of immune organs in ducklings could be influenced by thermal manipulation during the middle stage of incubation. To evaluate this hypothesis, a control group was incubated under a normal temperature from E11 to E24, while the incubation temperature of the experimental group was increased by 1 °C. Our results indicated that slight changes in the incubation temperature significantly repressed the bursa of Fabricius index of the duck embryo on E25 (F1, 58=122.51, P<0.0001) and significantly repressed the spleen index of neonatal ducklings (F1, 58=74.38, P<0.0001). At 0 day posthatching (dph) and 14 dph, ducklings hatched from eggs incubated under the higher temperature had a lower percentage of globulin than the control group (F1, 10=19.97, P=0.0111; F1, 10=9.8, P=0.0352). The IFN-γ concentration of ducklings at 14 dph displayed the same trend (F1, 10=284.49, P<0.0001). These results suggested that thermal manipulation during the middle stage of incubation had a repressive effect on the development of immune organs and reduced the concentrations of serum globulin and IFN-γ. These results demonstrated that the subtle alteration of incubation temperature may weaken ducklings' immunity.     

Reduced β2-GPI is associated with increased platelet aggregation and activation in patients with prolonged isolated thrombocytopenia after allo-HSCT

We aimed to measure platelet function and its relationship with β2-GPI in prolonged isolated thrombocytopenia(PT) after allogeneic hematopoietic stem cell transplantation(allo-HSCT). Fifty-six patients with PT and 60 allo-HSCT recipients without PT(non-PT controls) were enrolled. Platelet aggregation and activation, β2-GPI and anti-β2-GPI antibody levels, vWF antigen,and vWF activity were analyzed. The effect of β2-GPI on platelet aggregation was also measured ex vivo. Results showed that ADP-induced platelet aggregation significantly increased(39%±7.5% vs. 23%±8.5%, P=0.032), and the platelet expression of both CD62 p(33.6%±11.6% vs. 8.5%±3.5%, P0.001) and PAC-1(42.4%±7.6% vs. 6.8%±2.2%, P0.001) was significantly higher in patients with PT than in those without PT. Significantly lower β2-GPI levels(164.2±12 μg m L–1 vs. 234.2±16 μg mL–1,P0.001), higher anti-β2-GPI IgG levels(1.78±0.46 U mL–1 vs. 0.94±0.39 U mL–1, P0.001), and increased vWF activity(133.06%±30.50% vs. 102.17%±25.90%, P0.001) were observed in patients with PT than in those without PT. Both ADPinduced platelet aggregation(n=116, r~2=-0.5042, P0.001) and vWF activity(n=116, r~2=-0.2872, P0.001) were negatively correlated with β2-GPI levels. In summary, our data suggested that platelet aggregation and activation were significantly higher in patients with PT than in those without PT, which might be associated with reduced β2-GPI levels. The reduced β2-GPI levels might be due to the existence of anti-β2-GPI IgG.     

Addressing the problems of base pairing and strand cyclization in template-directed synthesis: a case for the utility and necessity of 'molecular midwives' and reversible backbone linkages for the origin of proto-RNA

Nucleic acid synthesis is precisely controlled in living organisms by highly evolved protein enzymes. The remarkable fidelity of information transfer realized between template and product strands is the result of both the spatial selectivity of the polymerase active site for Watson-Crick base pairs at the point of nucleotide coupling and subsequent proof-reading mechanisms. In the absence of naturally derived polymerases, in vitro template-directed synthesis by means of chemically activated mononucleotides has proven remarkably inefficient and error-prone. Nevertheless, the spontaneous emergence of RNA polymers and their protein-free replication is frequently taken as a prerequisite for the hypothetical 'RNA world'. We present two specific difficulties that face the de novo synthesis of RNA-like polymers in a prebiotic (enzyme-free) environment: nucleoside base selection and intramolecular strand cyclization. These two problems are inherent to the assumption that RNA formed de novo from pre-existing, chemically-activated mononucleotides in solution. As a possible resolution to these problems, we present arguments and experimental support for our hypothesis that small molecules (referred to as 'molecular midwives') and alternative backbone linkages (under equilibrium control) facilitated the emergence of the first RNA-like polymers of life.     

In situ proteolysis for protein crystallization and structure determination

We tested the general applicability of in situ proteolysis to form protein crystals suitable for structure determination by adding a protease (chymotrypsin or trypsin) digestion step to crystallization trials of 55 bacterial and 14 human proteins that had proven recalcitrant to our best efforts at crystallization or structure determination. This is a work in progress; so far we determined structures of 9 bacterial proteins and the human aminoimidazole ribonucleotide synthetase (AIRS) domain.     

Streptomycin-induced ribosome engineering complemented with fermentation optimization for enhanced production of 10-membered enediynes tiancimycin-A and tiancimycin-D

Tiancimycins (TNMs) are a group of 10-membered anthraquinone-fused enediynes, newly discovered from Streptomyces sp. CB03234. Among them, TNM-A and TNM-D have exhibited excellent antitumor performances and could be exploited as very promising warheads for the development of anticancer antibody-drug conjugates (ADCs). However, their low titers, especially TNM-D, have severely limited following progress. Therefore, the streptomycin-induced ribosome engineering was adopted in this work for strain improvement of CB03234, and a TNMs high producer S. sp. CB03234-S with the K43N mutation at 30S ribosomal protein S12 was successfully screened out. Subsequent media optimization revealed the essential effects of iodide and copper ion on the production of TNMs, while the substitution of nitrogen source could evidently promote the accumulation of TNM-D, and the ratio of produced TNM-A and TNM-D was responsive to the change of carbon and nitrogen ratio in the medium. Further amelioration of the pH control in scaled up 25 L fermentation increased the average titers of TNM-A and TNM-D up to 13.7 ± 0.3 and 19.2 ± 0.4 mg/L, respectively. The achieved over 45-fold titer improvement of TNM-A, and 109-fold total titer improvement of TNM-A and TNM-D enabled the efficient purification of over 200 mg of each target molecule from 25 L fermentation. Our efforts have demonstrated a practical strategy for titer improvement of anthraquinone-fused enediynes and set up a solid base for the pilot scale production and preclinical studies of TNMs to expedite the future development of anticancer ADC drugs.     

One-step Condensation/copolymerization of VTES and DVB for Self-assembly Bionic Superhydrophobic Surface Coating and Study on Oil-water Separation

Mimicry of nature drives the development of bionic materials.Bionic superhydrophobic materials are a kind of high-efficiency materials to handle oil spills and ...     

A facile fluorescence turn-on biosensor customized for monitoring of protein kinase activity based on carboxylic carbon nanoparticle–peptide complexes

In this study, we present a facile and low-cost approach for detecting protein kinase A (PKA) by assembling a purpose-designed carboxyfluorescein (FAM)-labelled peptide with carboxylic carbon nanoparticles (CNPs). Fluorescence of the FAM-labelled peptide gradually decreases to a low background signal as a result of the electron transfer from CNPs to FAM-labelled peptide via the peptide, which acts as a bridge. The reaction in the sensor in the presence of adenosine 5′-triphosphate and PKA phosphorylates the substrate peptide and disrupts the electrostatic repulsive force between the CNPs and the peptide, therefore altering the spectroscopic signal of the system. The change in fluorescence signal was directly proportional to the PKA concentration in the range 0–1.8 U/ml with a detection limit of 0.04 U/ml. These results suggest that PKA activity can be effectively measured using the developed PKA biosensor. Moreover, the fluorescence biosensor was successfully used in the investigation of PKA in spiked human embryonic kidney (HEK) 293 cells lysates, indicating its potential applications in protein kinase-related biochemical fundamental research.