Protein kinase C delta regulates Ser46 phosphorylation of p53 tumor suppressor in the apoptotic response to DNA damage

The p53 tumor suppressor is activated in the cellular response to genotoxic stress. Transactivation of p53 target genes dictates cell cycle arrest and DNA repair or induction of apoptosis; however, a molecular mechanism responsible for these distinct functions remains unclear. Recent studies revealed that phosphorylation of p53 on Ser(46) was associated with induction of p53AIP1 expression, resulting in the commitment of the cell fate into apoptotic cell death. Moreover, upon exposure to genotoxic stress, p53DINP1 was expressed and recruited a kinase(s) to p53 that specifically phosphorylated Ser(46). Here, we show that the pro-apoptotic kinase, protein kinase C delta (PKCdelta), is involved in phosphorylation of p53 on Ser(46). PKCdelta-mediated phosphorylation is required for the interaction of PKCdelta with p53. The results also demonstrate that p53DINP1 associates with PKCdelta upon exposure to genotoxic agents. Consistent with these results, PKCdelta potentiates p53-dependent apoptosis by Ser(46) phosphorylation in response to genotoxic stress. These findings indicate that PKCdelta regulates p53 to induce apoptotic cell death in the cellular response to DNA damage.     

Inhibition of intestinal glucose uptake by aporphines and secoaporphines

The effects of aporphines and secoaporphines on glucose uptake by isolated intestinal brush-border membrane vesicles (BBMV) or basolateral membrane vesicles (BLMV) and glucose absorption during in situ intestinal perfusion were studied. Of the tested compounds, N-allylsecoboldine was the most potent glucose uptake inhibitor, with IC50 values of 159 microM and 121 microM, respectively, for uptake by BBMV and BLMV. While thaliporphine competitively inhibited glucose uptake by both membrane preparations, inhibition by N-allylsecoboldine was competitive using BBMV and noncompetitive using BLMV. In addition, N-allylsecoboldine significantly reduced both glucose absorption during in situ intestinal perfusion and blood glucose levels in the oral glucose tolerance test. The results demonstrate that levels of both aporphines and secoaporphines achievable by oral administration have an inhibitory effect on intestinal glucose uptake and suggest that the hypoglycemic effects of these compounds merit attention.     

F0F1-ATPase as biosensor to detect single virus

F(0)F(1)-ATPase within chromatophore was constructed as a biosensor (immuno-rotary biosensor) for the purpose of capturing single virus. Capture of virus was based on antibody-antigen reaction. The detection of virus based on proton flux change driven by ATP-synthesis of F(0)F(1)-ATPase, which was indicated by F1300, was directly observed by a fluorescence microscope. The results demonstrate that the biosensor loading of virus particles has remarkable signal-to-noise ratio (3.8:1) compared to its control at single molecular level, and will be convenient, quick, and even super-sensitive for detecting virus particles.     

Arginine vasopressin in the caudate nucleus plays an antinociceptive role in the rat

Our previous work has shown that arginine vasopressin (AVP) regulates antinociception through brain nuclei rather than the spinal cord and peripheral organs. The present study investigated the nociceptive effect of AVP in the caudate nucleus (CdN) of the rat. Microinjection of AVP into the CdN increased pain threshold in a dose-dependent manner, while local administration of AVP-receptor antagonist-d(CH(2))(5)Tyr(Et)DAVP decreased pain threshold. Pain stimulation elevated AVP concentration in CdN perfuse liquid. CdN pretreatment with AVP-receptor antagonist completely reversed AVP's effect on pain threshold in the CdN. The data suggest that AVP in the CdN is involved in antinociception.     

PQN and DQN: algorithms for expression microarrays

An ideal expression algorithm should be able to tell truly different expression levels with small false positive errors and be robust to assay changes. We propose two algorithms. PQN is the non-central trimmed mean of perfect match intensities with quantile normalization. DQN is the non-central trimmed mean of differences between perfect match and mismatch intensities with quantile normalization. The quantiles for normalization can be either empirical or theoretical. When array types and/or assay change in a study, the normalization to common quantiles at the probe set level is essential. We compared DQN, PQN, RMA, GCRMA, DCHIP, PLIER and MAS5 for the Affymetrix Latin square data and our data of two sets of experiments using the same bone marrow but different types of microarrays and different assay. We found the computation for AUC of ROC at affycomp.biostat.jhsph.edu can be improved.     

Comparative studies on histological and ultra-structure of the pituitary of different ploidy level fishes

The histological and ultra-structure of the pituitary in diploid red crucian carp(Carassius auratus red var.),triploid crucian carp and allotetraploid hybrids within and after the breeding season were comparatively studied.The result showed that there were six endocrine cell types in the pituitary of these three kinds of fishes,and there was an obvious difference in cell size among different ploidy level fishes.As for the same type of pituitary cells,the cell size was increased gradually with the in- creasing ploidy level.In the breeding season,the allotetraploid hybrids had higher proportion of go- nadotropin cells(GTH)than triploids,and the triploids had higher proportion of GTH than diploids.The results were related to the earlier sexual maturity of allotetraploid hybrids and sterility of triploid cru- cian carp.On the other hand,among the three kinds of fishes,the proportion of somatotropin(STH) cells in triploids crucian carp was the highest,whereas that in allotetraploid hybrids was the lowest. The results might be connected with the faster growth rate of triploids and slower growth rate of al- lotetraploid hybrids.In addition,in GTH cells of meso-adenohypophysis after the breeding season, there were many endocrine particles in triploids,while those endocrine particles were released from the cells in allotetraploids and diploids.This result showed that the sterility of triploid crucian carp might be related to the hormone which was not released from the GTH cells.In a word,the present study indicated that the differences in the structure of pituitary among different ploidy level fishes contributed to their difference in the growth rate and gonadal development.     

Influence of Phytase Transgenic Corn on the Intestinal Microflora and the Fate of Transgenic DNA and Protein in Digesta and Tissues of Broilers

An experiment was conducted to investigate the effect of phytase transgenic corn (PTC) on intestinal microflora, and the fate of transgenic DNA and protein in the digesta and tissues of broilers. A total of 160 1-day-old Arbor Acres commercial male broilers were randomly assigned to 20 cages (8 chicks per cage) with 10 cages (replicates) for each treatment. Birds were fed with a diet containing either PTC (54.0% during 1–21 days and 61.0% during 22–42 days) or non-transgenic isogenic control corn (CC) for a duration of 42 days. There were no significant differences (P>0.05) between birds fed with the PTC diets and those fed with the CC diets in the quantities of aerobic bacteria, anaerobic bacteria, colibacillus and lactobacilli, or microbial diversities in the contents of ileum and cecum. Transgenic phyA2 DNA was not detected, but phyA2 protein was detected in the digesta of duodenum and jejunum of broilers fed with the PTC diets. Both transgenic phyA2 DNA and protein fragments were not found in the digesta of the ileum and rectum, heart, liver, kidney, and breast or thigh muscles of broilers fed with the PTC diets. It was concluded that PTC had no adverse effect on the quantity and diversity of gut microorganisms; Transgenic phyA2 DNA or protein was rapidly degraded in the intestinal tract and was not transferred to the tissues of broilers.     

Seasonal and Spatial Variations of Bulk Nitrogen Deposition and the Impacts on the Carbon Cycle in the Arid/Semiarid Grassland of Inner Mongolia,China

Atmospheric nitrogen (N) deposition is an important component that affects the structure and function of different terrestrial ecosystem worldwide. However, much uncertainty still remains concerning the magnitude of N deposition on grassland ecosystem in China. To study the spatial and temporal patterns of bulk N deposition, the levels of N (NH₄ ⁺-N and NO₃ ^--N) concentration in rainfall were measured at 12 sites across a 1200 km grassland transect in Inner Mongolia, China, and the respective N deposition rates were estimated. The inorganic N deposition rates ranged from 4.53 kg N ha^-1 to 12.21 kg N ha^-1 with a mean value of 8.07 kg N ha^-1 during the entire growing season, decreasing steadily from the eastern to the western regions. Inorganic N deposition occurred mainly in July and August across meadow steppe, typical steppe, and desert steppe, which corresponded to the seasonal distribution of mean annual precipitation. A positive relationship was found between inorganic N deposition and mean annual precipitation (R² = 0.54 ~ 0.72, P < 0.0001) across the grassland transect. Annual estimation of inorganic N deposition was 0.67 Pg yr^-1 in Inner Mongolia, China based on the correlation between N deposition rates and precipitation. N deposition was an important factor controlling aboveground biomass and ecosystem respiration, but has no effect on root biomass and soil respiration. We must clarify that we used the bulk deposition samplers during the entire sampling process and estimated the dissolved NH₄ ⁺-N and NO₃ ^--N deposition rates during the entire growing season. Long-term N deposition monitoring networks should be constructed to study the patterns of N deposition and its potential effect on grassland ecosystem, considering various N species, i.e., gaseous N, particle N, and wet N deposition.     

拟南芥根毛衰老死亡过程的PCD检测

根毛是植物体吸收养分的重要器官, 自然条件下根毛的寿命很短, 仅能存活2–3周, 随即脱落死亡。以模式植物拟南芥(Arabidopsis thaliana)根毛为材料, 对根毛死亡的细胞学特征进行了报道。结果发现, 根毛衰老死亡后细胞内的原生质体发生了收缩, 并在胞质中观察到凝集物的出现; 通过原位末端标记(TUNEL)检测, 发现幼根上的根毛细胞核DNA发生了片段化。上述结果表明, 拟南芥根毛的衰老死亡很可能是植物体自主调控的程序性细胞死亡(PCD)。另外, 当根毛衰老死亡后,细胞核大多会迁移到靠近根毛基部的位置, 且正常的长管状根毛发生旋转扭曲。     

The secondary structure of ribonuclease P RNA, the catalytic element of a ribonucleoprotein enzyme

Secondary structure models for the ribonuclease (RNAase) P RNAs of Bacillus subtilis and E. coli were derived by a phylogenetic comparative analysis of published sequences as well as four novel ones. The RNAase P RNA genes from Bacillus megaterium, Bacillus brevis, Bacillus stearothermophilus, and Pseudomonas fluorescens were cloned, sequenced, and compared with the other available sequences. Regions of pairing were identified by the occurrence of homologous complementary sequences that vary among the compared molecules. A common core of primary and secondary structure can be identified in all these RNAase P RNAs. The previously noted striking differences between the Bacillus and the enteric RNAase P RNAs arise not only from point mutations, but from the addition or deletion of structural domains. The primary and secondary structural features that are common to all of the RNAase P RNAs are likely to be the elements involved in the binding and cleavage of tRNA precursors, and in the interaction with the RNAase P protein.