SU8 bio-chemical sensor microarrays

Microfabricated cantilevers have recently attracted considerable attention as novel label-free chemical and biological biosensors which translate surface reactions into nanomechanical bending motion. However these studies have primarily focused on commercially available silicon cantilevers and relatively little work has been performed on cantilevers fabricated from other materials. Polymeric materials, offer significant advantages over silicon by virtue of the low Young's modulus, ease of microfabrication and reduced cost. In this paper, we report a non-vacuum fabrication process to produce arrays of SU8 cantilevers and demonstrate their application as chemical sensors using in situ reference cantilevers. © 2006 Elsevier B.V. All rights reserved.

云南保种乳用圭山羊遗传多样性蛋白电泳研究

采用水平式淀粉胶蛋白电泳技术,对路南保种乳用圭山羊33个个体的46个遗传座位的血液蛋白及同工酶的多态性进行了研究。结果发现AKP、LAP、CES-I、ESD、ME和Pa6个座位具多态性,多态座位的基因AKP~(0)、LAP~(A)、CES-I~(1)、ME~(B)、ESD~(1)和Pa~(A)的基因频率较高;多态座位百分比P=0.1304,平均杂合度H=0.0501。在Tf座位,出现两种表型AA、AB,但多态性贫乏;LDH谱带中发现一种不同的类型。

Molecular evolution of CXCR1, a G protein-coupled receptor involved in signal transduction of neutrophils

Human neutrophils are a type of white blood cell, which forms an early line of defense against bacterial infections. Neutrophils are highly responsive to the chemokine, interleukin-8 (IL-8) due to the abundant distribution of CXCR1, one of the IL-8 receptors on the neutrophil cell surface. As a member of the GPCR family, CXCR1 plays a crucial role in the IL-8 signal transduction pathway in neutrophils. We sequenced the complete coding region of the CXCR1 gene in worldwide human populations and five representative nonhuman primate species. Our results indicate accelerated protein evolution in the human lineage, which was likely caused by Darwinian positive selection. The sliding window analysis and the codon-based neutrality test identified signatures of positive selection at the N-terminal ligand/receptor recognition domain of human CXCR1.

Accelerated evolution of the pituitary adenylate cyclase-activating polypeptide precursor gene during human origin

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide abundantly expressed in the central nervous system and involved in regulating neurogenesis and neuronal signal transduction. The amino acid sequence of PACAP is extremely conserved across vertebrate species, indicating a strong functional constraint during the course of evolution. However, through comparative sequence analysis, we demonstrated that the PACAP precursor gene underwent an accelerated evolution in the human lineage since the divergence from chimpanzees, and the amino acid substitution rate in humans is at least seven times faster than that in other mammal species resulting from strong Darwinian positive selection. Eleven human-specific amino acid changes were identified in the PACAP precursors, which are conserved from murine to African apes. Protein structural analysis suggested that a putative novel Deuropeptide might have originated during human evolution and functioned in the human brain. Our data suggested that the PACAP precursor gene underwent adaptive changes during human origin and may have contributed to the formation of human cognition.

Adaptive evolution of MRGX2, a human sensory neuron specific gene involved in nociception

MRGX2, a G-protein-coupled receptor, is specifically expressed in the sensory neurons of the human peripheral nervous system and involved in nociception. Here, we studied DNA polymorphism patterns and evolution of the MRGX2 gene in world-wide human populations and the representative nonhuman primate species. Our results demonstrated that MRGX2 had undergone adaptive changes in the path of human evolution, which were likely caused by Darwinian positive selection. The patterns of DNA sequence polymorphisms in human populations showed an excess of derived substitutions, which against the expectation of neutral evolution, implying that the adaptive evolution of MRGX2 in humans was a relatively recent event. The reconstructed secondary structure of the human MRGX2 revealed that three of the four human-specific amino acid substitutions were located in the extra-cellular domains. Such critical substitutions may alter the interactions between MRGX2 protein and its ligand, thus, potentially led to adaptive changes of the pain-perception-related nervous system during human evolution. (c) 2005 Elsevier B.V. All rights reserved.

Rapid evolution, genetic variations, and functional association of the human spermatogenesis-related gene NYD-SP12

NYD-SP12 is a recently identified spermatogenesis-related gene with a pivotal role in human testis development. In this study, we analyzed between-species divergence and within-species variation of NYD-SP12 in seven representative primate species, four wo

Detecting positive darwinian selection in brain-expressed genes during human evolution

To understand the genetic basis that underlies the phenotypic divergence between human and non-human primates, we screened a total of 7176 protein-coding genes expressed in the human brain and compared them with the chimpanzee orthologs to identity genes

棕点湍蛙皮肤分泌液中促胰岛素释放肽的分离纯化、基因克隆及活性分析

通过分离纯化棕点湍蛙(Amolops loloensis)皮肤分泌液中的生物活性物质,得到有促胰岛素释放活性的分离峰,并鉴定其结构.采用葡聚糖Sephadex G-50凝胶层析和反相高效液相(RP-HPLC)等手段对棕点湍蛙皮肤分泌液进行分离纯化,利用胰岛素释放实验进行活性检测,Edman降解法测定活性峰的氨基酸序列,反转录法构建cDNA文库并克隆其基因.得到一个具有显著的促胰岛素释放活性的十六肽,测得其氨基酸序列为:FMPIvGKsMSGLSGKL-NH2,命名为amolopin-1.由cDNA(开放阅读框为192bp)推导的氨基酸一级结构显示,其前体由64个氨基酸残基(aa)组成,包括高度保守的信号肽(22aa),酸性肽以及成熟肽.经过数据库序列比对,从棕点湍蛙皮肤中得到一个新的促胰岛素释放肽,进一步分析其作用机理和药代动力学,极有可能得到一个新的治疗糖尿病的降糖药物.