日本七鳃鳗的二型体态

于国内首次揭示了日本七鳃鳗的二型体态现象,指出了国内文献资料对日本七鳃鳗特征描述的片面性,同时推出1个修正后的七鳃鳗种的检索表。     

脊椎动物Sox基因家族的系统发生分析

脊椎动物Sox基因是一类高度保守的基因家族,它们编码一类转录因子,参与多种发育过程的调控,这个家族的共有特征是Sox蛋白具有一个约79个氨基酸,可与DNA特异结合的HMG盒区,该基因家族成员众多复杂,对它们的基因结构,功能及进化关系的研究有助于对该基因家族的全面认识,利用已克隆的全部脊椎动物全长核苷酸／蛋白质数据,对这些数据进行序列比对及进化树的构建,分析Sox基因家族成员的分类及分子进化模式。     

Genome-wide Identification and Characterization of a Dehydrin Gene Family in Poplar (Populus trichocarpa)

Dehydrins (DHNs) define a complex group of stress inducible proteins characterized by the presence of one or more lysine-rich motifs. DHNs are present in multiple copies in the genome of plant species. Although genome-wide analysis of DHNs composition and chromosomal distribution has been conducted in herbaceous species, it remains unexplored in woody plants. Here, we report on the identification of ten genes encoding eleven putative DHN polypeptides in Populus. We document that DHN genes occur as duplicated blocks distributed over seven of the 19 poplar chromosomes likely as a result of segmental and tandem duplication events. Based on conserved motifs, poplar DHNs were assigned to four subgroups with the K_n subgroup being the most frequent. One putative DHN polypeptide (PtrDHN-10) with a SKS arrangement could originate from a recombination between SK_n and K_nS genes. In silico analysis of microarray data showed that in unstressed poplar, DHN genes are expressed in all vegetative tissues except for mature leaves. This exhaustive survey of DHN genes in poplar provides important information that will assist future studies on their functional role in poplar.     

Novel cysteine-rich secretory protein in the buccal gland secretion of the parasitic lamprey, Lethenteron japonicum

Lampreys are one of the most primitive vertebrates diverged some 500 million years ago. It has long been known that parasitic lampreys secrete anticoagulant from their buccal glands and prevent blood coagulation of host fishes. We found two major protein components of 160 and 26 kDa in the buccal gland secretion of parasitic river lamprey, Lethenteron japonicum. The larger protein was identified as river lamprey plasma albumin. The complete primary structure of the 26-kDa protein was determined by protein and cDNA analysis. It belonged to the cysteine-rich secretory protein (CRISP) superfamily that includes recently identified reptile venom ion-channel blockers. Lamprey CRISP blocked depolarization-induced contraction of rat-tail arterial smooth muscle, but showed no effect on caffeine-induced contraction. The result suggests that lamprey CRISP is an L-type Ca(2+)-channel blocker and may act as a vasodilator, which facilitates the parasite to feed on the host's blood. The lamprey CRISP protein contains a number of short insertions throughout the sequence, when aligned with reptilian venom CRISP proteins, probably due to the large evolutionary distance between the Agnatha and the Reptilia, and may represent a novel class of venom CRISP family proteins.     

Control of Locomotion in a Lower Vertebrate, the Lamprey: Brainstem Command Systems and Spinal Cord Regeneration

SYNOPSIS. The lamprey, a lower vertebrate, has recently becomea very useful model system for studying motor control, includingthe organization of neural networks, and for examining the relationbetween kinematic patterns and underlying neural mechanisms.This aquatic animal displays a number of interesting locomotorbehaviors, including flexure reflexes, forward locomotion, backwardlocomotion, turning, withdrawal, and equilibrium reflexes. Avaluable property of the lamprey preparation is that the nervoussystem survives under in vitro conditions for several days andgenerates well-coordinated locomotor activity that underliessome of the above behaviors. Thus, the neural control of basiclocomotor behaviors can be studied in an isolated nervous systemin which the ionic or pharmacological make-up of the bath canbe altered and in which stable conditions are provided for intracellularrecordings. In addition, recent data indicate that the lampreypreparation is a valuable model system for studies of axonalregeneration and recovery of locomotor function following spinalcord injury. This article will focus on three aspects of locomotorbehavior in the lamprey: kinematics and motor activity of locomotorbehaviors, descending control of locomotion, and regenerationof descending brainstem command pathways that initiate locomotion.     

Characterization and the Expression Analysis of Nitrate Transporter (NRT) Gene Family in Pineapple

Nitrate is the preferred nitrogen source of higher plants and an essential nutrient for plant growth and development. Nitrate transporters (NRTs) play vital roles in the nitrate uptake and transportation. However, the NRT gene family in pineapple is still unexplored. In this study, we performed a genome-wide analysis of the pineapple genome and identified 48 NRT genes (AcNRTs) distributed unevenly across 9 chromosomes and 2 scaffolds. Phylogenetic analysis showed that these genes can be divided into three groups, namely, AcNRT1/PTR, AcNRT2 and AcNRT3/NAR1 with 44, 3 and 1 members, respectively. AcNRTs within the same phylogenetic group share similar gene structure and domain composition. In addition, syntenic and phylogenetic analyses identified 34 Arabidopsis NRT genes with 31 pineapple NRT genes as orthologs. By investigating the expression profiles of these genes in various tissues, we showed that the expression pattern of some AcNRTs genes is tissue-specific. Furthermore, we examined the expression of the AcNRT2s under nitrate starvation and found that AcNRT2.1 and AcNRT2.2 both have the strongest response in roots suggesting that AcNRTs may play a broad role in the pineapple in response to nitrate deficiency. Taken together, our data provide insights into the evolution and function of pineapple NRTs and pave a path for future functional investigation of pineapple NRTs genes.     

Cloning and Characterization of a Novel Member of the Human Mad Gene Family (MADH6)

MAD (mothers against decapentaplegic)-related proteins (MADRs) are intracellular components that play critical roles in signal-transduction pathways involving the transforming growth factor β (TGFβ) superfamily. Some Mad genes are candidates for tumor-suppressor functions. From a human fetal brain cDNA library we have isolated a novel Mad-related gene. Two alternatively transcribed mRNAs encode deduced 430- and 467-amino-acid peptides that showed high levels of similarity to MADR1/Smad1/hMAD1 (about 80% identity at the amino acid level). This gene, which we designated MADH6, resides on 13q12–q14 between BRCA2 and RB, a region that frequently displays loss of heterozygosity in breast, liver, and prostate cancers.     

Glutamic Acid Decarboxylase in Sea Lamprey (Petromyzon marinus): Characterization, Localization, and Developmental Changes

Abstract: We have carried out assays for glutamic acid decarboxylase (GAD) in homogenates of brain and spinal cord from larval and adult sea lamprey ( Petromyzon marinus ). The enzyme had similar characteristics in both stages. Optimal pH was 6.8; optimal temperature was 27–30° C; K _m at 27°C was 5 mM. GAD activity was distributed uniformly along the length of the spinal cord. Specific activities for the larval cord and brain were 26 and 63 nm CO₂/mg protein/h. respectively. The specific activities for the adult cord and brain were 29 and 236 nm CO₂/mg protein/h, respectively. Thus, the activity of cord homogenates did not change significantly between larval and adult stages, but that of the brain increased about fourfold.     

萝卜全基因组中LBD基因家族成员的鉴定与分析

LBD基因家族是植物所特有的一类转录因子,在植物生长发育过程中起到非常重要的作用。本研究利用生物信息学方法,从萝卜基因组中鉴定出分布于9条染色体上的59个LBD基因。该家族成员结构比较简单,内含子数均不超过3个。萝卜LBD基因可分为两大类,分别包含50个和9个成员。它们在染色体上的分布不均匀,1号染色体上基因数目最多,有18个,而7号和8号染色体分别仅有1个LBD基因。对它们在不同组织和发育时期的表达模式研究发现,该基因家族具有一定的时空表达特异性,预测其参与萝卜不同的发育过程。本研究为萝卜LBD基因家族的功能分析奠定了基础。     

玉米JAZ家族基因ZmJAZ4的克隆及功能分析

JAZ(Jasmonate ZIM-domain)蛋白是植物特有的一类转录因子,通过抑制茉莉素调控基因的表达,在植物的生长发育及非生物胁迫等方面发挥重要的功能。从玉米B73自交系中克隆到一个新的JAZ家族基因Zm JAZ4,该基因c DNA全长为651bp,编码蛋白含有216个氨基酸,分子量约为23.1 k D,p I为10.78,属于碱性蛋白。Real-time RT-PCR结果表明,Zm JAZ4主要在茎端分生组织、雄穗、发育早期的种子以及胚乳中表达。系统进化分析显示,Zm JAZ4与At JAZ10转录因子相似性较高。亚细胞定位试验表明,Zm JAZ4定位于细胞核内。Zm JAZ4在酵母细胞中不具有转录激活活性。激素及胁迫处理表明,Zm JAZ4在地上部的表达受PEG、Na Cl、SA、GA和ABA诱导,而在地下部的表达受到ABA和GA诱导。结果分析表明,Zm JAZ4可能是一个重要的转录调控因子,参与调控多种激素信号通路及非生物胁迫响应。     

Complete Characterization of the Human ABC Gene Family

The human ATP-binding cassette (ABC) transporters comprise a large family of membrane transport proteins and play a vital role in many cellular processes. The genes provide functions as diverse as peptide transport, cholesterol and sterol transport, bile acid, retinoid, and iron transport. In addition some ABC genes play a role as regulatory elements. Many ABC genes play a role in human genetic diseases, and several are critical drug transport proteins overexpressed in drug resistant cells. Analysis of the gene products allows the genes to be grouped into seven different subfamilies.     

On the Modes of the Formation of the Exoskeleton in Early Jawless Vertebrates (Osteostraci,Agnatha)

Based on recently obtained original and published data on the fine structure of the external skeleton of osteostracan agnathans (Osteostraci, Agnatha), possible modes of the formation of their hard cover in the course of the horizontal growth of the exoskeleton are characterized. The developmental models for the formation of various configurations of cephalothoracic shields typical for osteostracans are revealed. It is shown that, in the morphogenesis of the hard cover of this group of early vertebrates, a significant part of the variants of the exoskeleton horizontal growth characteristic of early vertebrates are observed.     

Lamprey (<Emphasis Type="Italic">Lethenteron japonicum</Emphasis>) IL-17 upregulated by LPS-stimulation in the skin cells

We report here the first evidence for interleukin-17, a pro-inflammatory cytokine, in cyclostomes. To detect the novel molecules involved in the immune response in the skin of the lamprey Lethenteron japonicum, subtractive hybridization was performed with 6-h-cultured skin cells with or without lipopolysaccharide (LPS). In approximately 100 partially sequenced clones analyzed, we identified an interesting sequence similar to that of the IL-17 genes in teleosts and mammals. Subsequent rapid amplification of cDNA ends was used to obtain the cDNA of lamprey IL-17 (LampIL-17) that contains a 519-bp open reading frame encoding a mature protein of 154 amino acids and a 19-residue NH₂-terminal signal peptide. The phylogenetic tree indicated that LampIL-17 is clustered into IL-17D, which is a subgroup of the IL-17 family. Southern blot analysis showed that the lamprey harbors a single copy of the LampIL-17 gene in its genome. The LampIL-17 gene was constitutively expressed in most tissues examined as well as in the skin, where the basal layer epithelial cells expressed LampIL-17 mRNA. Real-time-polymerase chain reaction (RT-PCR) demonstrated that the LampIL-17 gene expression in LPS-stimulated skin cells tended to be greater than that in non-stimulated cells. These results suggest that LampIL-17 is responsible for defense against bacterial infections in the lamprey skin. Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number AB303391.     

Characterization of a Rice Gene Family Encoding Type-A Diterpene Cyclases

We have previously isolated and characterized the rice (Oryza sativa) cDNAs, OsCyc1/OsCPS4, OsCyc2/OsCPS2, OsKS4, OsDTC1/OsKS7, OsDTC2/OsKS8 and OsKS10, which encode cyclases that are responsible for diterpene phytoalexin biosynthesis. Among the other members of this gene family, OsCPS1 and OsKS1 have been suggested as being responsible for gibberellin biosynthesis, OsKSL11 has recently been shown to encode stemodene synthase, and the functions of the three other diterpene cyclase genes in the rice genome, OsKS3, OsKS5 and OsKS6, have not yet been determined. In this study, we show that recombinant OsKS5 and OsKS6 expressed in E. coli converted ent-copalyl diphosphate into ent-pimara-8(14),15-diene and ent-kaur-15-ene, respectively. Neither product is a hydrocarbon precursor required in the biosynthesis of either gibberellins or phytoalexins. OsKS3 may be a pseudogene from which the translated product is a truncated enzyme. These results suggest that the diterpene cyclase genes responsible for gibberellin and phytoalexin biosynthesis are not functionally redundant.     

Evolution of the Vertebrate Cytosolic Malate Dehydrogenase Gene Family: Duplication and Divergence in Actinopterygian Fish

Abstract A general correlation between neural expression and negative charge in isozymes suggests charge represents an adaptation to the neural environment. Interestingly, a notable exception exists in teleost fish. Two cytosolic malate dehydrogenase (MDH) isozymes have different spatial expression patterns in certain fishes: one is expressed in all tissues and the second is expressed primarily in the eye and skeletal muscle. While the neural MDH isozyme is negatively charged, the difference in charge between the two isozymes is not as pronounced as that observed in other gene families (e.g., triosephosphate isomerase and lactate dehydrogenase). Most tetrapods express a single cytosolic MDH isozyme, and it has been demonstrated recently that the pair of isozymes found in teleosts results from a gene duplication sometime after the separation of teleosts and tetrapods, although the exact timing of this duplication has not been inferred. Phylogenetic analyses suggest that the duplication of teleost isozymes occurred during the radiation of actinopterygian fish, consistent with the timing of duplication at other loci. Using inferred amino acid sequences, we examine the pattern of change following the duplication and across the rest of the MDH gene tree. Comparison between the MDH gene family and another gene family that shows a larger charge differential among members (triosephosphate isomerase) indicates that the smaller charge difference between MDH isozymes is best explained by greater constraint on amino acid change directly following the duplication, not greater constraint across the entire gene tree. This difference in constraint might result from the wider pattern of expression of the “neural” MDH isozyme.