富含亮氨酸蛋白LRP130抗体在恶性肿瘤中的表达和临床意义

目的:探讨富含亮氨酸蛋白LRP130抗体(LRPPRC)在胃癌、宫颈癌和前列腺癌的表达和临床意义。方法:应用免疫组化法检测120例胃癌、80例宫颈癌和198例前列腺癌组织中LRPPRC的表达;分析LRPPRC的表达和临床病理学参数的关系。结果:胃癌和正常胃组织LRPPRC的高表达率分别为71.7%(86/120)和21.7%(13/60),二者差异有统计学意义(P<0.001);宫颈癌和正常宫颈组织LRPPRC的高表达率分别为76.3%(61/80)和27.5%(11/40),二者差异有统计学意义(P<0.001);前列腺癌和前列腺增生组织LRPPRC的高表达率分别为61.6%(122/198)和18.0%(18/100),二者差异有统计学意义(P<0.001)。LRPPRC的高表达与前列腺癌患者的Gleason评分、血清PSA水平、雄激素阻断治疗后PSA下降水平和转移部位的数量相比呈显著正相关(P<0.05)。结论:恶性肿瘤组织LRPPRC表达增高;晚期前列腺癌LRPPRC的高表达预示恶性程度高和多发转移。

The Arabidopsis AS2 Gene Encoding a Predicted Leucine-zipper Protein Is Required for the Leaf Polarity Formation

The asymmetric leaves2 ( as2) is a classical Arabidopsis thaliana (L.) Heynh. mutant that shows leaf lobes and leaflet-like structures from the petioles of leaves. Genetic and molecular analyses have demonstrated that the AS2 function is required for repression of meristem-related homeobox genes in leaves. In this study, we describe phenotypic characterizations of new as2 alleles that are in the Landsberg erecta (Ler) genetic background. In addition to the as2 phenotypes reported previously, the new as2 mutants have some leaves with petiole growth underneath the leaf blade, showing a lotus-leaf structure. More severe rosettes leaves of the as2 mutants form a filament-like structure, reflecting a loss of the adaxial-abaxial polarity in leaves. Among as2 mutants analyzed in different genetic backgrounds, only those that are in the Ler genetic background resulted in a high frequency of the lotus-leaf structure. We have isolated the AS2 gene by map-based gene cloning. The predicted AS2 protein contains a leucine-zipper motif, and its N-terminus shares high levels of sequence similarity to those of a group of predicted proteins with no known biological functions. AS2 transcripts were detected in leaves, flowers and fruits, but absent in stems, consistent with the mutant phenotypes.

Dietary Leucine Requirement of Juvenile Japanese Seabass(Lateolabrax Japonicus)

A 56-day feeding trial was conducted to examine the dietary leucine requirement of juvenile Japanese seabass in sea- water floating net cages （1.5 m × 1.5 m × 2.0 m）. Six isonitrogenous （crude protein 40%） and isoenergetic （gross energy 20 kJ g-1） diets were formulated to contain different concentrations of leucine （0.9%, 1.49%, 2.07%, 2.70%, 3.30% and 3.88% of dry matter）. Crys- talline L-amino acids were supplemented to simulate the whole body amino acid pattern of Japanese seabass except for leucine. Three groups （30 fish individuals each, 8.0g±0.20g in initial weight） were fed to apparent satiation at 5：00 and 17：30 every day. During the experimental period, the water temperature ranged from 26 to 32℃ and salinity from 26 to 30, and the dissolved oxygen was maintained at 7mgL-l. The results showed that weight gain （WG）, nitrogen retention （NR）, feed efficiency （FE） and protein efficiency ratio （PER） were significantly increased when dietary leucine was increased from 0.90% to 2.70% of dry matter, and then declined. WG was the highest when fish were fed D4 containing 2.70% of leucine. No significant differences were observed in body composition among dietary treatments （P 〉 0.05）. Considering the change of WG, the optimum dietary leucine requirement of juve- nile Japanese seabass was either 2.39% of dry matter or 5.68% of dietary protein.

Genome Sequencing and Phylogenetic Analysis of Three Avian Influenza H9N2 Subtypes in Guangxi

Three isolates of H9N2 Avian Influenza viruses (AIV) were isolated from chickens in Guangxi province. Eight pairs of specific primers were designed and synthesized according to the sequences of H9N2 at GenBank. phylogenetic analysis showed a high degree of homology between the Guangxi isolates and isolates from Guangdong and Jiangsu provinces, suggesting that the Guangxi isolates originated from the same source. However, the eight genes of the three isolates from Guangxi were not in the same sublineages in their respective phylogenetic trees, which suggests that they were products of natural reassortment between H9N2 avian influenza viruses from different sublineages. The 9 nucleotides ACAGAGATA which encode amino acids T, G, I were absent between nucleotide 205 and 214 in the open reading frame of the NA gene in the Guangxi isolates. AIV strains that infect human have, in their HA proteins, leucine at position 226. The analysis of deduced amino acid sequence of HA proteins showed that position 226 of these isolates contained glycine instead of leucine, suggesting that these three isolates differ from H9N2 AIV strains isolated from human infections.

Bioinformatic Analysis of zm ERECTA-LIKE2Gene from Zea mays

Zm ERECTA-LIKE2 sequences were isolated according to the Zea mays genome. The study indicates that zm ERECTALIKE2 is composed of 2 410 nucleotides and encodes a receptor-like kinase which consists of 774 amino acids by biological analysis. The results show that zm ERECTA-LIKE2 protein contains 13 domains of leucine-rich repeats and belongs to the PKclike family, it is a liposoluble protein, with a conserved transmembrane region.

Leucine and histidine independently regulate milk protein synthesis in bovine mammary epithelial cells via mTOR signaling pathway

The aim of this study is to investigate the effects of leucine（Leu） and histidine（His） on the expression of both the mammalian target of rapamycin（mTOR） signaling pathway-related proteins and caseins in immortalized bovine mammary epithelial cells（CMEC-H）, using a single supplement through Western blotting. The Earle＇s balanced salt solution（EBSS） was set as the control group and other treatment groups, based on the EBSS, were added with different concentrations of Leu or His, respectively. The results showed that, compared with the control group, the expression of caseins and the phosphorylation of mTOR（Ser^2481）, Raptor（Ser^792）, e IF4E（Ser^209）, and e EF2（Thr^56） increased with the Leu concentrations ranging from 0.45 to 10.80 mmol/L（P〈0.01）. The P-4EBP1（Thr^37） at 10.80 mmol/L Leu, and P-RPS6（Ser^235/236） at 5.40 to 10.80 mmol/L Leu all decreased. Similarly, the His supplementation from 0.15 to 9.60 mmol/L increased the expression of αs2-casein, β-casein, κ-casein, P-mTOR（Ser^2481）, P-Raptor（Ser^792）, P-S6K1（Thr^389）, P-4EBP1（Thr^37）, P-e IF4E（Ser^209）, and P-e EF2（Thr^56）（P〈0.01） in CMEC-H, whereas the αs1-casein expression was only reduced at 9.60 mmol/L His, G protein β subunit-like protein（GβL） at 0.15 and 9.60 mmol/L His, and P-RPS6 at 4.80 to 9.60 mmol/L His. Our linear regression model assay suggested that the αs1-casein expression was positively correlated with P-mTOR（P〈0.01）, P-S6K1（P〈0.01）, and P-e EF2（P〈0.01） for the addition of Leu, while the expressions of β-casein（P〈0.01） and κ-casein（P〈0.01） were positively correlated with P-e EF2 for the addition of His. In conclusion, the milk protein synthesis was up-regulated through activation of the mTOR pathway with the addition of Leu and His in CMEC-H.

Crystal structure of a plant leucine rich repeat protein with two island domains

Leucine rich repeat(LRR)domain,characterized by a repetitive sequence pattern rich in leucine residues,is a universal protein-protein interaction motif present in all life forms.LRR repeats interrupted by sequences of 30 70 residues(termed island domain,ID)have been found in some plant LRR receptor-like kinases(RLKs)and animal Toll-like receptors(TLR7-9).Recent studies provide insight into how a single ID is structurally integrated into an LRR protein.However,structural information on an LRR protein with two IDs is lacking.The receptor-like protein kinase 2(RPK2)is an LRR-RLK and has important roles in controlling plant growth and development by perception and transduction of hormone signal.Here we present the crystal structure of the extracellular LRR domain of RPK2(RPK2-LRR)containing two IDs from Arabidopsis.The structure reveals that both of the IDs are helical and located at the central region of the single RPK2-LRR solenoid.One of them binds to the inner surface of the solenoid,whereas the other one mainly interacts with the lateral side.Unexpectedly,a long loop immediately following the N-terminal capping domain of RPK2-LRR is presented toward and sandwiched between the two IDs,further stabilizing their embedding to the LRR solenoid.A potential ligand binding site formed by the two IDs and the solenoid is located at the C-terminal side of RPK2-LRR.The structural information of RPK2-LRR broadens our understanding toward the large family of LRR proteins and provides insight into RPK2-mediated signaling.

Energetics of protein backbone hydrogen bonds and their local electrostatic environment

MD simulation study of several peptides including a polyalanine,a helix(pdb:2I9M),and a leucine zipper were carried out to investigate hydrogen bond energetics using dynamic polarized protein-specific charge(DPPC)to account for the polarization effect in protein dynamics.Results show that the backbone hydrogen-bond strength is generally correlated with its specific local electrostatic environment,measured by the number of water molecules near the hydrogen bond in the first solvation shell.The correlation coefficient is found to be 0.89,0.78,and 0.80,respectively,for polyalanine,2I9M protein,and leucine zipper.In the polyalanine,the energies of the backbone hydrogen bonds are very similar to each other due to their similar local electrostatic environment.The current study helps demonstrate and support the understanding that hydrogen bonds are stronger in a hydrophobic surrounding than in a hydrophilic one.For comparison,the result from simulation using standard force field shows a much weaker correlation between hydrogen bond energy and local electrostatic environment due to the lack of polarization effect in the force field.