Growth densities regulate the response to elevated CO2 in a farmed seaweed Pyropia haitanensis (Bangiales,Rhodophyta)

Journal of Applied Phycology - Atmospheric CO2 concentration is predicted to nearly double by the end of this century. There are a large number of reports on the effects of elevated atmospheric CO2...     

留茬免耕播种对河西绿洲灌区春小麦出苗和产量的影响

本研究通过田间定位试验,探讨了河西绿洲灌区单作小麦、小麦/玉米间作、小麦/大豆间作3种典型春小麦生产模式下,长期留茬免耕播种对春小麦出苗和产量的影响,为该区域春小麦高效可持续生产提供理论依据。结果表明: 与传统翻耕相比,留茬免耕播种小麦/玉米和小麦/大豆间作的小麦出苗率、出苗均匀度下降明显,降幅分别为3.3%～8.6%、9.6%～20.5%和2.9%～8.8%、10.7%～61.7%;单作小麦的出苗均匀度有所提高,其中2019年显著增加14.9%,而出苗率在2020年显著降低4.2%;3种种植方式下,春小麦麦苗整齐度均有所下降。留茬免耕播种3种种植模式下,春小麦成穗数在收获时均与传统翻耕处理持平,差异不显著。3种模式下的春小麦均可以通过提高穗粒数和千粒重来弱化出苗对产量的影响,在收获时,春小麦籽粒产量的增幅分别为10.3%～12.9%(单作小麦)、10.5%～11.9%(小麦/玉米间作)和10.3%～22.5%(小麦/大豆间作),均达到显著水平。在农田风蚀退化极其严重的河西绿洲灌区,留茬免耕播种是春小麦生产中切实可行的耕作措施。     

Copper Nitrate Catalyzed Three-Component One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones

Abstract

An efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones from aldehydes, 1,3-dicarbonyl compounds, and urea using copper nitrate under refluxing temperature in ethanol was described. Compared with other Lewis copper salts, copper nitrate proved to be the most efficient. The advantages of the new method were good yields (61–93%), short reaction time (0.4–3 h), and inexpensive catalyst.     

Multiple gene genealogical analyses of a nematophagous fungus Paecilomyces lilacinus from China

Paecilomyces lilacinus is a geographically widespread nematophagous fungus and a promising biological control agent against plant parasitic nematodes. However, relatively little is known about its patterns of genetic variation through its broad geographic and ecological contexts. In this study, we analyzed the genetic variation of 2 virulence-associated genes (PLS and PLC) and 4 housekeeping gene fragments (ITS, RPB1, RPB2, and β-tubulin) among 80 P. lilacinus specimens collected from 7 locations in China. Various degrees of polymorphism and haplotype diversity were observed among the six gene fragments. However, no genetic differentiation was observed among the geographic populations, consistent with extensive gene flow among these geographic populations of P. lilacinus in China. Our analysis also suggested that clonal reproduction was the predominant mode of reproduction in natural populations of P. lilacinus.     

Antiviral Nucleoside Drug Delivery via Amino Acid Phosphoramidates

Abstract

Stable and water soluble amino acid phosphomonoester amidates of AZT were synthesized and shown to have potent anti-HIV-1 activity. Intracellular and cell extract metabolism studies revealed that these compounds are likely to be enzymatically converted to the corresponding monophosphates. In addition, we have shown that the half life and tissue distribution of a phosphoramidate of AZT is 5 and 10-fold greater, respectively, than AZT.     

Nucleoside Modification and Concerted Mutagenesis of the Human A3 Adenosine Receptor to Probe Interactions Between the 2-Position of Adenosine Analogs and Gln167 in the Second Extracellular Loop

Residues of the second extracellular loop are believed to be important for ligand recognition in adenosine receptors. Molecular modeling studies have suggested that one such residue, Gln ¹⁶⁷ of the human A ³ receptor, is in proximity to the C2 moiety of some adenosine analogs when bound. Here this putative interaction was systematically explored using a neoceptor strategy, i.e., by site-directed mutagenesis and examination of the affinities of nucleosides modified to have complementary functionality. Gln ¹⁶⁷ was mutated to Ala, Glu, and Arg, while the 2-position of several adenosine analogs was substituted with amine or carboxylic acid groups. All compounds tested lost affinity to the mutant receptors in comparison to the wild type. However, comparing affinities among the mutant receptors, several compounds bearing charge at the 2-position demonstrated preferential affinity for the mutant receptor bearing a residue of complementary charge. 13, with a positively-charged C2 moiety, displayed an 8.5-fold increase in affinity at the Q167E mutant receptor versus the Q167R mutant receptor. Preferential affinity for specific mutant receptors was also observed for 8 and 12. The data suggests that a direct contact is made between the C2 substituent of some charged ligands and the mutant receptor bearing the opposite charge at position 167.     

Investigation on Side-Spray Fluidized Bed Granulation with Swirling Airflow

Top-spray fluidized bed granulation with axial fluidization airflow from the bottom of the granulator is well-established in the pharmaceutical industry. The application of swirling airflow for fluidized bed granulation was more recently introduced. This study examined the effects of various process parameters on the granules produced by side-spray fluidized bed with swirling airflow using the central composite and Box–Behnken design of experiment. Influence of the amount of binder solution, spray rate, and distance between spray nozzle and powder bed were initially studied to establish operationally viable values for these parameters. This was followed by an in-depth investigation on the effects of inlet airflow rate, atomizing air pressure and distance between spray nozzle and powder bed on granule properties. It was found that the amount of binder solution had a positive correlation with granule size and percentage of lumps but a negative correlation with size distribution and Hausner ratio of the granules. Binder solution spray rate was also found to affect the granules size. High drug content uniformity was observed in all the batches of granules produced. Both inlet airflow rate and atomizing air pressure were found to correlate negatively with granule size and percentage of lumps but correlate positively with the size distribution of the granule produced. Percentage of fines was found to be significantly affected by inlet airflow rate. Distance between spray nozzle and powder bed generally affected the percentage of lumps.     

Regulation of ICAM‐1 expression in gingival fibroblasts infected with high‐glucose‐treated P. gingivalis

Porphyromonas gingivalis is a major pathogen in the initiation and progression of periodontal disease, which is recognized as a common complication of diabetes. ICAM‐1 expression by human gingival fibroblasts (HGFs) is crucial for regulating local inflammatory responses in inflamed periodontal tissues. However, the effect of P. gingivalis in a high‐glucose situation in regulating HGF function is not understood. The P. gingivalis strain CCUG25226 was used to study the mechanisms underlying the modulation of HGF ICAM‐1 expression by invasion of high‐glucose‐treated P. gingivalis (HGPg). A high‐glucose condition upregulated fimA mRNA expression in P. gingivalis and increased its invasion ability in HGFs. HGF invasion with HGPg induced increases in the expression of ICAM‐1. By using specific inhibitors and short hairpin RNA (shRNA), we have demonstrated that the activation of p38 MAPK and Akt pathways is critical for HGPg‐induced ICAM‐1 expression. Luciferase reporters and chromatin immunoprecipitation assays suggest that HGPg invasion increases NF‐κB‐ and Sp1‐DNA‐binding activities in HGFs. Inhibition of NF‐κB and Sp1 activations blocked the HGPg‐induced ICAM‐1 promoter activity and expression. The effect of HGPg on HGF signalling and ICAM‐1 expression is mediated by CXC chemokine receptor 4 (CXCR4). Our findings identify the molecular pathways underlying HGPg‐dependent ICAM‐1 expression in HGFs, providing insight into the effect of P. gingivalis invasion in HGFs.