Substituted dipiperidine alcohols as potent CCR2 antagonists

The synthesis and biological evaluation of a series of substituted dipiperidine alcohols are described. Structure-activity relationship studies led to the discovery of potent CCR2 antagonists displaying IC(50) values in the nanomolar or subnanomolar range. The cinnamoyl compounds had higher binding affinities than the corresponding urea analogs.     

Diffusion coefficients in the lateral intercellular spaces of Madin-Darby canine kidney cell epithelium determined with caged compounds.

The diffusion coefficients of two caged fluorescent dyes were measured in free solution and in the lateral intercellular spaces (LIS) of cultured Madin-Darby canine kidney (MDCK) cells after photoactivation by illumination with a continuous or pulsed UV laser. Both quantitative video imaging and a new photometric method were utilized to determine the rates of diffusion of the caged fluorescent dyes: 8-((4,5-dimethoxy-2-nitrobenzyl)oxy)pyrene-1,3,6-trisulfonic acid (DMNB-HPTS) and (4,5-dimethoxy-2-nitrobenzyl) fluorescein dextran (10,000 MW) (DMNB-caged fluorescein dextran). The diffusion coefficients at 37 degrees C in free solution were 3.3 x 10(-6) cm2/s (HPTS) and 0.98 x 10(-6) cm2/s (10,000 MW dextran). Diffusion of HPTS within nominally linear stretches of the LIS of MDCK cells grown on glass coverslips was indistinguishable from that in free solution, whereas dextran showed a 1.6 +/- 0.5-fold reduction in diffusivity. Measurements of HPTS diffusion within the LIS of multicellular regions also exhibited a diffusivity comparable to the free solution value. The restriction to diffusion of the dextran within the LIS may be due to molecular hindrance.     

The efficacy of DNA barcoding in the classification,genetic differentiation,and biodiversity assessment of benthic macroinvertebrates

Macroinvertebrates have been recognized as key ecological indicators of aquatic environment and are the most commonly used approaches for water quality assessment. However, species identification of macroinvertebrates (especially of aquatic insects) proves to be very difficult due to the lack of taxonomic expertise in some regions and can become time‐consuming. In this study, we evaluated the feasibility of DNA barcoding for the classification of benthic macroinvertebrates and investigated the genetic differentiation in seven orders (Insecta: Ephemeroptera, Plecoptera, Trichoptera, Diptera, Hemiptera, Coleoptera, and Odonata) from four large transboundary rivers of northwest China and further explored its potential application to biodiversity assessment. A total of 1,144 COI sequences, belonging to 176 species, 112 genera, and 53 families were obtained and analyzed. The barcoding gap analysis showed that COI gene fragment yielded significant intra‐ and interspecific divergences and obvious barcoding gaps. NJ phylogenetic trees showed that all species group into monophyletic species clusters whether from the same population or not, except two species (Polypedilum. laetum and Polypedilum. bullum). The distance‐based (ABGD) and tree‐based (PTP and MPTP) methods were utilized for grouping specimens into Operational Taxonomic Units (OTUs) and delimiting species. The ABGD, PTP, and MPTP analysis were divided into 177 (p = .0599), 197, and 195 OTUs, respectively. The BIN analysis generated 186 different BINs. Overall, our study showed that DNA barcoding offers an effective framework for macroinvertebrate species identification and sheds new light on the biodiversity assessment of local macroinvertebrates. Also, the construction of DNA barcode reference library of benthic macroinvertebrates in Eurasian transboundary rivers provides a solid backup for bioassessment studies of freshwater habitats using modern high‐throughput technologies in the near future.     

Quantitative analysis of cytoplasmic actin gene promoter and nuclear polyhedrosis virus immediate-early promoter activities in various tissues of silkworm Bombyx mori using recombinant Autographa californica nuclear polyhedrosis virus as vector

Cassettes harboring luciferase reporter driven by Bombyx mori cytoplasmic actin gene promoter (A3) (671 bp) and B. mori nuclear polyhedrosis virus immediate-early promoter (IE-1) (580 bp) were transferred to the bacmid AcΔEGT to generate the recombinant Autographa californica nuclear polyhedrosis viruses, AcNPVA3Luc and AcNPVIELuc, respectively. Recombinant baculoviruses were injected into the hemocoele of newly ecdysed 5th instar larvae. The activities of the A3 and IE-1 promoters in various tissues were measured by luciferase activity assay and normalized by the copy number of recombinant virus. Results showed that the activity of the A3 promoter was approximately 10-fold higher than the IE-1 promoter. The promoter activities of A3 and IE-1 were highest in the silk gland, followed by fat body, middle gut, Malpighian tubule, and hemocyte. In silk gland, activity of the two promoters was highest in posterior silk gland, followed by middle and anterior silk glands. The difference in promoter activities reflects the growth speed of tissue in silkworm larvae. The activity of the A3 promoter remained unchanged and was not inhibited significantly by viral factors at least 3–4 d post injection of rAcNPV.     

玉米花粉单倍体植株染色体上异染色质的变异

我们用Giemsa BSG C-带技术检查了玉米花药培养获得的花粉单倍体植株根尖细胞染色体上异染色质的变异,观察结果表明,有的植株所显示的C-带数目是与供体植株的相一致,有的植株所显示的C-带数目则发生了显著变化,其中有的增加,有的减少。并讨论了异染色质发生变异的可能原因。还相应地观察到间期核中染色中心的变化是与中期染色体上C-带数目的变化相一致。