广州蕨类植物增补(续)

报道了广州蕨类植物新记录种13种,隶属于10科11属.其中姬蕨科为广州新记录科.     

云贵高原及横断山区莲座蕨科植物地理分布

依据云南大学植物标本馆蕨类植物标本室(PYU)和国内主要标本馆保存的莲座蕨科植物标本,以及多年来积累的研究资料,建立该科植物在云南的产地GIS数据库。以此为基础,分析云南莲座蕨科植物空间分布的多样性和特有性,及其在云贵高原及横断山区的地理分布特征。研究结果如下：① 云南莲座蕨科植物种类丰富,分布海拔范围为100~2400m;② 滇东南是莲座蕨科植物分布的多样性和特有性中心,其多样性由滇东南向西、北方向递减;③ 云南有莲座蕨科2个属分布,即莲座蕨属(Angiopteris)和原始莲座蕨属(Archangiopteris),其中原始莲座蕨属的物种多样性较低而特有性较高。初步分析了该科植物中5个广布种和1个高山峡谷种分布格局的成因,以及5个特有种的发生史,推断广布种的分布格局形成于第四纪冰期之前,高山峡谷种的分布格局形成于第三纪之后,而特有种的主要成因可能是自然杂交和边缘效应。     

安徽祁门地区蕨类植物区系研究

安徽祁门地区蕨类植物共有107种(包括变种、变型),隶属于28科56属,其中发现安徽地理分布新记录种1个,即丝带蕨(Drymotaenium miyoshianum)。该区的蕨类植物优势科为鳞毛蕨科(Dryopte ridaceae)、水龙骨科(Polypodiaceae)和蹄盖蕨科(Athyriaceae);优势属为鳞毛蕨属(Dryopteris)、卷柏属(Selaginella)和复叶耳蕨属(Arachniodes)。属的地理成分以泛热带为主,亚热带和温带分布次之;种的地理分布则以中国-日本分布和中国特有分布为主。祁门蕨类植物区系在区系区划上应属于典型的华东地区。该区的蕨类植物生态类型以土生为主。种的相似性分析和属的聚类分析表明:该区系与三清山和天童山的关系密切,而与白石砬子等关系疏远。     

福建蕨类植物新资料

对凤丫蕨属(裸子蕨科)井冈山凤丫蕨一新变型,即条纹凤丫蕨(Coniogramme jinggangshanensis Ching et Shing f.zebrina X.X.Wang et M.M.Lin)和福建新记录种漏斗瓶蕨(Trichomanes naseana),碗蕨(Dennstaedtia scabra),桃花岛鳞毛蕨(Dryopteris hondoensis)和尖齿拟水龙骨(Polypodiastrum argutum)进行了报道.     

香港蕨类植物新记录

报道了香港蕨类植物新记录种5种,即台湾轴脉蕨(Ctenitopsis kusukuensis)、掌叶线蕨(Colysis digi-tata)、德化鳞毛蕨(Dryopteris dehuaensis)、海岛鳞始蕨(Lindsaeaorbiculatavar.commixta)和石松(Lycopo-diumclavatum),其中包括两个新记录属轴脉蕨属(Ctenitopsis)和石松属(Lycopodium)。另外,还列出了每个种的重要特征及其与相关种类的差异。     

山东植物2个新记录属

报道了山东植物2个新记录属:荚果蕨属(Matteuccia Todaro)及其新记录种荚果蕨(Matteuccia struthiopteris(Linnaeus)Todaro),觿茅属(Dimeria Robert Brown)及其新记录种觿茅(Dimeria ornithopoda Trinius)。凭证标本均存放于山东中医药大学药学院标本室(SDCM)。     

广东蕨类植物新资料

报道了2个新异名,1个新等级和35种蕨类植物在广东的分布新记录。正安肋毛蕨（Ctenitis changanensis Ching）和信宜铁角蕨（Asplenium xinyiense Ching et S.H.Wu）分别作直鳞肋毛蕨（Ctenitis eatoni (Bak.) Ching）和厚叶铁角蕨（Asplenium griffithianum Hook）的异名处理;齿翅井栏凤尾蕨（Pteris serralata（Miau）Y. H. Yan）被提升到种的等级;假芒萁属（Sticherus Presl）、柄盖蕨属（Peranema D. Don）、蛾眉蕨属（Lunathyrium Koidz.）和革舌蕨属（Scleroglossum Alderw）等4个属为广东分布新记录,小笠原卷柏（Selaginella boninensis Baker）为中国大陆分布新记录。广东现有蕨类已达到56科144属502种。     

海南鹦哥岭自然保护区蕨类植物区系

在充分的野外调查的基础上,初步探讨了海南鹦哥岭自然保护区蕨类植物的区系组成、生态分布与濒危状况。初步结果如下:1.鹦哥岭现有蕨类植物50科119属282种,科、属、种的比例分别占海南蕨类科、属、种的89·3%、84·4%和62·7%,其中台湾马尾杉(Phlegmariurus taiwanensis)、粗齿桫椤(Al-sophila denticulata)、启无蹄盖蕨(Athyrium wangii)、紫柄蕨(Pseudophegopteris pyrrhorachis)、微红新月蕨(Pronephrium megacuspe)、羽裂圣蕨(Dictyocline wilfordii)、多羽复叶耳蕨(Arachniodes amoena)、华南鳞毛蕨(Dryopteris tenuicula)等8种为海南分布新记录种。2.鹦哥岭蕨类区系以水龙骨科(Polypodiaceae)、蹄盖蕨科(Athyriaceae)、金星蕨科(Thelypteridaceae)、铁角蕨科(Aspleniaceae)为优势科,以铁角蕨属(Aspleni-um)、凤尾蕨属(Pteris)、短肠蕨属(Allantodia)、卷柏属(Selaginella)、毛蕨属(Cyclosorus)等为优势属,是一个以热带成分为主的热带区系,兼有较高比例的地区特有成分和东亚成分,其中,热带分布的科、属、种的比例分别为97·3%、88·3%和63·4%。3.鹦哥岭蕨类的生活环境大致可以区分为4种类型:低海拔次生林或灌草丛干旱生境、中高海拔林下阴湿生境、中高海拔林下湿润溪流生境和高海拔湿润苔藓矮林生境,以中高海拔林下阴湿生境中的蕨类最为丰富。4.鹦哥岭保存有许多海南珍稀蕨类,有10种国家二级保护蕨类,有56种海南受威胁蕨类,其中海南蹄盖蕨(Athyrium hainanense)、和七指蕨(Helminthostachys zeylanica)为海南极危种(CR),另有17种海南濒危(EN)、37种海南易危(VU)蕨类。     

福建蕨类植物新资料

报道福建蕨类植物新记录2种,分别为水龙骨科瓦韦属丝带蕨Lepisorus miyoshianus(Makino)Fraser-JenkinsSubh.和鳞毛蕨科舌蕨属舌蕨Elaphoglossum marginatum T.Moore。凭证标本存放于福建长汀圭龙山自然保护区植物标本室(FGNR)。     

广州市蕨类植物物种多样性研究

依据文献、标本与野外调查,简要回顾了历史上记录的广州蕨类植物,阐明了广州目前分布的蕨类植物的种类、区系特点、生态与地理分布、以及珍稀蕨类植物的种类与保护现状.广州地区有蕨类植物37科82属176种,其中乔芒萁(Dicranopteris gigantea)、刺边膜蕨(Hymenophyllm spinosum)和裸果鳞毛蕨(Dryopteris gymnosora)为广东分布新记录.广州蕨类植物区系以金星蕨科(Thelypteridaceae)、鳞毛蕨科(Dryopteridaceae)、水龙骨科(Polypo-diaceae)、蹄盖蕨科(Athyriaceae)和风尾蕨科(Pteridaceae)的植物最为丰富,没有本地特有种,亚洲热带亚热带分布成分和东亚分布成分占绝对优势.这176种蕨类植物中,约80%的种类生活在密林阴湿生境,约20%生活在疏林或灌草丛干旱生境,只有2种水生蕨类植物.在水平分布上,广州蕨类植物呈北多南少的分布格局,约90%的种类汇集在广州东北部的从化山区,74种在广州仅见于该山区.从物种多度上看,个体数量多(Cop2)的有33种,尚多(Cop1)的有48种,稀少(Sp)的有53种,很少(So1)的有41种.华南马尾杉(Phlegmariurus austrosbzicus)、福建观音座莲(Angiopteris fokiensis)、刺边膜蕨(Hymenophy llum spmosum)、粗齿桫椤(Alsophila denticulata)、小黑桫椤(A.m etteniana)、黑桫椤(A.podophylla)、桫椤(A.spinulosa)、水蕨(Ceratopteris thdictroides)、羽裂叶双盖蕨(Diplazium tomitaroanum)、闽浙圣蕨(Dictyocline mingchegensts)、微毛凸轴蕨(Metathelypteris adscendens)、峨眉茯蕨(Leptogramma scdlanll)、苏铁蕨(Brainea insignis)、珠芽狗脊(Woodwardia prolifera)和黑鳞复叶耳蕨(Arachniodes nigrospinosa)等15种被评估为广州的珍稀植物,它们亟待有效的保护.     

不同浓度Ni、Cu处理对骆驼蓬光合作用和叶绿素荧光特性的影响水

以骆驼蓬幼苗为材料,采用盆栽试验研究不同浓度(0、50、100、200、400 mg·kg-1)Ni、Cu处理对骆驼蓬叶片光合作用、叶绿素荧光特性及生长状况的影响.结果表明:随着Ni浓度的增加,骆驼蓬幼苗叶片的光合色素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、PS Ⅱ最大光化学效率(Fv/Fm)、PS Ⅱ电子传递量子产率(φpsⅡ)、光化学猝灭系数(qp)及各项生长指标均呈显著下降趋势,而细胞间隙CO2浓度(Ci)和非光化学猝灭系数(qn)呈显著增加趋势,其中Pn的下降主要是由非气孔限制所致;骆驼蓬幼苗叶片的光合色素含量、Pn、Gs、Tr、Ci、Fv/Fm、φpsⅡ、qp及各项生长指标均在50 mg·kg-1Cu处理时达到峰值,叶绿素a和b、Pn、Gs、Tr、Ci、Fv/Fm及各项生长指标值在100 mg·kg-1Cu处理时仍微高于对照,而后随Cu浓度的增加,光合色素含量、Pn、Gs、Tr、Ci、Fv/Fm、φpsⅡ、qp及各项生长指标均呈下降趋势,qN呈增加趋势,其中Pn的下降主要是由气孔限制所致.     

Design of peptide oxytocin antagonists with strikingly higher affinities and selectivities for the human oxytocin receptor than atosiban.

The peptide oxytocin (OT) antagonist atosiban, approved for tocolytic use in Europe (under the tradename Tractocile), represents an important new therapeutic advance for the treatment of premature labor. This paper presents some new peptide OT antagonists which offer promise as superior tocolytics. The solid phase synthesis is reported of four pairs of L and D-2-naphthylalanine (L/D-2Nal) position-2 modified analogs of the following four oxytocin (OT) antagonists: des-9-glycinamide [1-(beta-mercapto-beta,beta-pentamethylene propionic acid), 2-O-methyltyrosine, 4-threonine]ornithine-vasotocin (desGly-NH(2),d(CH(2))(5)[Tyr(Me)(2),Thr(4)]OVT) (A); the Tyr-NH(2) (9) analog of (A), d(CH(2))(5)[Tyr(Me)(2),Thr(4),Tyr-NH(2) (9)]OVT (B); the Eda(9) analog of (A), d(CH(2))(5)[Tyr(Me)(2),Thr(4),Eda(9)]OVT (C); and the retro COCH(2)Ph(4-0H)(10) modified analog of (C), d(CH(2))(5)[Tyr(Me)(2),Thr(4),Eda(9)<-- COCH(2)Ph(4-0H)(10)]OVT (D). The eight new analogs of A-D are (1) desGly-NH(2),d(CH(2))(5)[D-2Nal(2),Thr(4)]OVT, (2) desGly-NH(2),d(CH(2))(5)[2-Nal(2),Thr(4)]OVT, (3) d(CH(2))(5)[D-2Nal(2),Thr(4),Tyr-NH(2) (9)]OVT, (4) d(CH(2))(5)[2Nal(2),Thr(4),Tyr-NH(2) (9)]OVT, (5) d(CH(2))(5)[D-2Nal(2),Thr(4),Eda(9)]OVT, (6) d(CH(2))(5)[2Nal(2),Thr(4),Eda(9)]OVT, (7) d(CH(2))(5)[D-2Nal(2),Thr(4),Eda(9)<-- COCH(2)Ph(4-0H)(10)]OVT, (8) d(CH(2))(5)[2Nal(2),Thr(4),Eda(9)<-- COCH(2)Ph(4-OH)(10)]OVT. Peptides 1-8 were evaluated for agonistic and antagonistic activities in in vitro and in vivo rat bioassays, in rat OT receptor (rOTR) binding assays and in human OT receptor (hOTR) and human vasopressin (VP) vasopressor (V(1a)) receptor (hV(1a)R) binding assays. Also reported are the hOTR and hV(1a)R affinity data for atosiban and for B. None of the eight peptides exhibit oxytocic or vasopressor agonism. Peptides 1-8 exhibit weak antidiuretic agonism (activities in the range 0.014-0.21 U/mg). Peptides 1-6 exhibit potent in vitro (no Mg(2+)) OT antagonism (anti-OT pA(2) values range from 7.63 to 8.08). Peptides 7 and 8 are weaker OT antagonists. Peptides 1-6 are all OT antagonists in vivo (estimated in vivo anti-OT pA(2) values in the range 6.94-7.23). Peptides 1-8 exhibit vasopressor antagonism, anti-V(1a) pA(2) values in the range 5.1-7.65. Peptides 1-8 exhibit high affinities for the rOTR (K(i) values = 0.3-7.8 nM). Peptides 1-4 and B exhibit surprisingly very high affinities for the hOTR; their K(i) values are 0.17, 0.29, 0.07, 0.14 and 0.59 nM, respectively. Peptides 1-4 and B exhibit respectively 449, 263, 1091, 546 and 129 times greater affinity for the hOTR than atosiban (K(i) = 76.4 nM). Peptides 1-4 exhibit high affinities for the hV(1a)R (K(i)s = 1.1 nM, 1.3 nM, 0.19 nM and 0.54 nM, all higher than the hV1(a)R affinities exhibited by atosiban (K(i) = 5.1 nM) and by B (K(i) = 5.26 nM). Because of their strikingly higher affinities for the hOTR than atosiban, peptides 1-4 and B exhibit gains in anti hOT/anti hV(1a) receptor selectivity compared with atosiban of 93, 64, 39, 56 and 127, respectively. These OT antagonists are thus promising candidates for development as potential new tocolytic agents.     

Characterisation and biological activity of Glu3 amino acid substituted GIP receptor antagonists

Glucose-dependent insulinotropic polypeptide (GIP) is an important gastrointestinal hormone, which regulates insulin release and glucose homeostasis, but is rapidly inactivated by enzymatic N-terminal truncation. Here we report the enzyme resistance and biological activity of several Glu(3)-substituted analogues of GIP namely; (Ala(3))GIP, (Lys(3))GIP, (Phe(3))GIP, (Trp(3))GIP and (Tyr(3))GIP. Only (Lys(3))GIP demonstrated moderately enhanced resistance to DPP-IV (p<0.05 to p<0.01) compared to native GIP. All analogues demonstrated a decreased potency in cAMP production (EC(50) 1.47 to 11.02 nM; p<0.01 to p<0.001) with (Lys(3))GIP and (Phe(3))GIP significantly inhibiting GIP-stimulated cAMP production (p<0.05). In BRIN-BD11 cells, (Lys(3))GIP, (Phe(3))GIP, (Trp(3))GIP and (Tyr(3))GIP did not stimulate insulin secretion with both (Lys(3))GIP and (Phe(3))GIP significantly inhibiting GIP-stimulated insulin secretion (p<0.05). Injection of each GIP analogue together with glucose in ob/ob mice significantly increased the glycaemic excursion compared to control (p<0.05 to p<0.001). This was associated with lack of significant insulin responses. (Ala(3))GIP, (Phe(3))GIP and (Tyr(3))GIP, when administered together with GIP, significantly reduced plasma insulin (p<0.05 to p<0.01) and impaired the glucose-lowering ability (p<0.05 to p<0.01) of the native peptide. The DPP-IV resistance and GIP antagonism observed were similar but less pronounced than (Pro(3))GIP. These data demonstrate that position 3 amino acid substitution of GIP with (Ala(3)), (Phe(3)), (Tyr(3)) or (Pro(3)) provides a new class of functional GIP receptor antagonists.     

Biosynthetic studies on the alpha-glucosidase inhibitor acarbose: the chemical synthesis of isotopically labeled 2-epi-5-epi-valiolone analogs

2-epi-5-epi-valiolone is a cyclization product of the C(7) sugar phosphate, sedoheptulose 7-phosphate, involved in the biosynthesis of the aminocyclitol moieties of acarbose, validamycin, and pyralomicin. As part of our investigation into the pathway from 2-epi-5-epi-valiolone to the valienamine moiety of acarbose, we prepared 1-epi-5-epi-(6-(2)H(2))valiolol [(6-(2)H(2))-6], 5-epi-(6-(2)H(2))valiolol [(6-(2)H(2))-17], 1-epi-2-epi-5-epi-(6-(2)H(2))valiolol [(6-(2)H(2))-12] and 2-epi-5-epi-(6-(2)H(2))valiolamine [(6-(2)H(2))-11]. Compounds (6-(2)H(2))-6 and (6-(2)H(2))-17 were synthesized from 2,3,4,6-tetra-O-benzyl-D-glucopyranose in 10 and seven steps, respectively, whereas (6-(2)H(2))-12 and (6-(2)H(2))-11 were synthesized from 2,3,4,6-tetra-O-benzyl-D-mannopyranose in eight and 10 steps, respectively.     

Probing hydration of monovalent cations condensed around polymeric nucleic acids

We report the relative molar sound velocity increments, [U], partial molar volumes, V(o), and partial molar adiabatic compressibilities, K(S)(o), of the Li(+), Na(+), K(+), Rb(+), Cs(+), NH(4)(+), and N(CH(3))(4)(+) salts of poly(dAdT)poly(dAdT), poly(dGdC)poly(dGdC), poly(dIdC)poly(dIdC), poly(rA)poly(rU), poly(rG)poly(rC), poly(rI)poly(rC), and poly(rU) at 25 degrees C. When analyzing these data, we take into account the Donnan membrane equilibrium effect. Comparison between the values of [U], V(o), and K(S)(o) exhibited by the nucleic acid salts and respective chlorides (LiCl, NaCl, KCl, RbCl, CsCl, NH(4)Cl, and N(CH(3))(4)Cl) yields information about the state of counterion hydration in the vicinity of each nucleic acid structure studied here. Our analysis reveals that the poly(dGdC)poly(dGdC), poly(dIdC)poly(dIdC), and poly(rI)poly(rC) duplexes and single-stranded poly(rU) do not significantly influence the hydration properties of their condensed counterions. In the vicinity of these polymers, counterions retain their full hydration shells (within +/-15%). By contrast, counterions condensed around the poly(dAdT)poly(dAdT), poly(rA)poly(rU), and poly(rG)poly(rC) duplexes are significantly dehydrated and retain, respectively, only 65(+/-18)%, 34(+/-21)%, and 33(+/-9)% of their original hydration shells. Taken together, the volumetric data reported here provide important new information that ultimately may help us understand the central role that hydration and counterions play in modulating the conformational preferences of nucleic acids and the energetics of DNA recognition events.     

1alpha,25(OH)2D3 causes a rapid increase in phosphatidylinositol-specific PLC-beta activity via phospholipase A2-dependent production of lysophospholipid

1alpha,25(OH)(2)D(3) activates protein kinase C (PKC) in rat growth plate chondrocytes via mechanisms involving phosphatidylinositol-specific phospholipase C (PI-PLC) and phospholipase A(2) (PLA(2)). The purpose of this study was to determine if 1alpha,25(OH)(2)D(3) activates PI-PLC directly or through a PLA(2)-dependent mechanism. We determined which PLC isoforms are present in the growth plate chondrocytes, and determined which isoform(s) of PLC is(are) regulated by 1alpha,25(OH)(2)D(3). Inhibitors and activators of PLA(2) were used to assess the inter-relationship between these two phospholipid-signaling pathways. PI-PLC activity in lysates of prehypertrophic and upper hypertrophic zone (growth zone) cells that were incubated with 1alpha,25(OH)(2)D(3), was increased within 30s with peak activity at 1-3 min. PI-PLC activity in resting zone cells was unaffected by 1alpha,25(OH)(2)D(3). 1beta,25(OH)(2)D(3), 24R,25(OH)(2)D(3), actinomycin D and cycloheximide had no effect on PLC in lysates of growth zone cells. Thus, 1alpha,25(OH)(2)D(3) regulation of PI-PLC enzyme activity is stereospecific, cell maturation-dependent, and nongenomic. PLA(2)-activation (mastoparan or melittin) increased PI-PLC activity to the same extent as 1alpha,25(OH)(2)D(3); PLA(2)-inhibition (quinacrine, oleyloxyethylphosphorylcholine (OEPC), or AACOCF(3)) reduced the effect of 1alpha,25(OH)(2)D(3). Neither arachidonic acid (AA) nor its metabolites affected PI-PLC. In contrast, lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE) activated PI-PLC (LPE>LPC). 1alpha,25(OH)(2)D(3) stimulated PI-PLC and PKC activities via Gq; GDPbetaS inhibited activity, but pertussis toxin did not. RT-PCR showed that the cells express PLC-beta1a, PLC-beta1b, PLC-beta3 and PLC-gamma1 mRNA. Antibodies to PLC-beta1 and PLC-beta3 blocked the 1alpha,25(OH)(2)D(3) effect; antibodies to PLC-delta and PLC-gamma did not. Thus, 1alpha,25(OH)(2)D(3) regulates PLC-beta through PLA(2)-dependent production of lysophospholipid.     

长江口低氧区异养细菌及氮磷细菌分布

2009年8月15-28日,对长江口低氧高发海域的异养细菌、无机磷细菌、有机磷细菌、反硝化细菌和氨化细菌的空间分布特征进行初步研究.结果表明:氨化细菌数量最高,表层水、底层水和表层沉积物的数量均值分别为307.52×104个·L-1、184.50×104个·L-1和199.97×102个·g-1;其次为异养细菌,数量均值分别为87.35×104 cfu·L-1、86.85×104cfu·L-1和64.26×102cfu·g-1;再次为有机磷细菌,数量均值分别为19.26×104 cfu·L-1、18.82×104cfu·L-1和19.56×102cfu·g-1;无机磷细菌只分布在长江口内和河口南槽至舟山海域,数量均值分别为18.50×104cfu·L-1、31.00×104cfu·L-1和7.17×102cfu·g-1;反硝化细菌分布广,但数量较低,均值分别为3.94×104个·L-1、23.08×104个·L-1和6.22×102个·g-1.相关性分析结果说明:盐度、硝酸盐、磷酸盐、硅酸盐和pH是影响水体和表层沉积物异养细菌、磷细菌和反硝化细菌分布的主要因子;底层水和表层沉积物异养细菌、磷细菌与水温呈显著正相关;底层水异养细菌和有机磷细菌与溶解氧(DO)呈显著正相关;表层沉积物无机磷细菌与DO呈显著正相关,氨化细菌与DO呈显著负相关.聚类分析结果说明:低氧对表层沉积物的细菌群落结构产生影响.     

Synthesis of bisphosphonate derivatives of ATP by T4 RNA ligase

T4 RNA ligase catalyzes the synthesis of ATP beta,gamma-bisphosphonate analogues, using the following substrates with the relative velocity rates indicated between brackets: methylenebisphosphonate (pCH(2)p) (100), clodronate (pCCl(2)p) (52), and etidronate (pC(OH)(CH(3))p) (4). The presence of pyrophosphatase about doubled the rate of these syntheses. Pamidronate (pC(OH)(CH(2)-CH(2)-NH(2))p), and alendronate (pC(OH)(CH(2)-CH(2)-CH(2)-NH(2))p) were not substrates of the reaction. Clodronate displaced the AMP moiety of the complex E-AMP in a concentration dependent manner. The K(m) values and the rate of synthesis (k(cat)) determined for the bisphosphonates as substrates of the reaction were, respectively: methylenebisphosphonate, 0.26+/-0.05 mM (0.28+/-0.05 s(-1)); clodronate, 0.54+/-0.14 mM (0.29+/-0.05 s(-1)); and etidronate, 4.3+/-0.5 mM (0.028+/-0.013 s(-1)). In the presence of GTP, and ATP or AppCCl(2)p the relative rate of synthesis of adenosine 5',5'-P(1),P(4)-tetraphosphoguanosine (Ap(4)G) was around 100% and 33%, respectively; the methylenebisphosphonate derivative of ATP (AppCH(2)p) was a very poor substrate for the synthesis of Ap(4)G. To our knowledge this report describes, for the first time, the synthesis of ATP beta,gamma-bisphosphonate analogues by an enzyme different to the classically considered aminoacyl-tRNA synthetases.     

Dipetalodipin, a novel multifunctional salivary lipocalin that inhibits platelet aggregation, vasoconstriction, and angiogenesis through unique binding specificity for TXA2, PGF2alpha, and 15(S)-HETE

Dipetalodipin (DPTL) is an 18 kDa protein cloned from salivary glands of the triatomine Dipetalogaster maxima. DPTL belongs to the lipocalin superfamily and has strong sequence similarity to pallidipin, a salivary inhibitor of collagen-induced platelet aggregation. DPTL expressed in Escherichia coli was found to inhibit platelet aggregation by collagen, U-46619, or arachidonic acid without affecting aggregation induced by ADP, convulxin, PMA, and ristocetin. An assay based on incubation of DPTL with small molecules (e.g. prostanoids, leukotrienes, lipids, biogenic amines) followed by chromatography, mass spectrometry, and isothermal titration calorimetry showed that DPTL binds with high affinity to carbocyclic TXA(2), TXA(2) mimetic (U-46619), TXB(2), PGH(2) mimetic (U-51605), PGD(2,) PGJ(2), and PGF(2α). It also interacts with 15(S)-HETE, being the first lipocalin described to date to bind to a derivative of 15-lipoxygenase. Binding was not observed to other prostaglandins (e.g. PGE(1), PGE(2), 8-iso-PGF(2α), prostacyclin), leukotrienes (e.g. LTB(4), LTC(4), LTD(4), LTE(4)), HETEs (e.g. 5(S)-HETE, 12(S)-HETE, 20-HETE), lipids (e.g. arachidonic acid, PAF), and biogenic amines (e.g. ADP, serotonin, epinephrine, norepinephrine, histamine). Consistent with its binding specificity, DPTL prevents contraction of rat uterus stimulated by PGF(2α) and induces relaxation of aorta previously contracted with U-46619. Moreover, it inhibits angiogenesis mediated by 15(S)-HETE and did not enhance inhibition of collagen-induced platelet aggregation by SQ29548 (TXA(2) antagonist) and indomethacin. A 3-D model for DPTL and pallidipin is presented that indicates the presence of a conserved Arg(39) and Gln(135) in the binding pocket of both lipocalins. Results suggest that DPTL blocks platelet aggregation, vasoconstriction, and angiogenesis through binding to distinct eicosanoids involved in inflammation.