针层孔菌属和嗜蓝孢孔菌属2新记录种(英文)

仲氏针层孔菌和假斑点嗜蓝孢孔菌为中国孔状木生真菌2新记录种。本文根据采集的标本材料提供了该2个种的详细描述和线条图。     

尾孢菌属和假尾孢属新记录种

报道中国尾孢菌属和假尾孢属3个新记录种,寄生在波状补血草Limonium sinuatum上的海岛尾孢Cercospora insulana,寄生在夹竹桃Nerium indicum上的来间岛假尾孢Pseudocercospora kurimensis和匍匐假尾孢P.repens。提供了形态描述和绘图。研究的标本保存在中国科学院菌物标本馆(HMAS)。     

厚孢孔菌属一新种

本文报道了厚孢孔菌属(Pachykytospora)的一个新种,即大厚孢孔菌Pachykytospora major G.Y.Zheng et Bi和一个国内新记录:瘤厚孢孔菌Pachykytospora tuberculosa(DC.:Fr.)Kotl.et Pouz.。     

中国的肉座菌科Ⅲ.肉座菌属的菌生种

对肉座菌属的系统分类史进行了回顾,并对3个菌生种进行了报道;其中硫磺肉座菌(新拟)Hypocrea sulphurea(Schwein.)Sacc.为中国新记录种,拟层孔肉座菌H.fomitopsisP.G.Liuet     

中国芮氏孔菌属一新记录种

介绍了芮氏孔菌属的特征,其中日本芮氏孔菌是中国木腐菌新记录种,该种采集于广西壮族自治区。根据中国的材料对该种进行了详细的描述和显微结构绘图。     

湖南张家界的丝孢菌 Ⅱ.尾孢菌属和假尾孢属

本文报道尾孢菌属的4个种和假尾孢属的5个种,其中有3个新组合:乌黑假尾孢[Pseudocercospora fuliginosa(Ell.& Kell.)Zhao & Guo,comb.nov.],安息香假尾孢[Pse-udocercospora styracae(Chupp)Guo & Zhao,comb.nov.],水红木假尾孢[Pseudocercosporaviburni-cylindrici(Tai)Guo & Zhao,comb.nov.]和一个中国新记录。文中对新组合进行了简要描述并绘图。研究的标本分别保存在中国科学院微生物研究所真菌标本室(HMAS)和中国林业科学研究院林业研究所(HPAF)。     

胶瘤菌属和孔生胶瘤菌——中国新记录属、种

该文通过形态特征研究和基于ITS序列的分子系统学分析,对采自甘肃省连城国家级自然保护区的1份形态特殊的胶瘤菌属标本进行分类学研究。结果表明：该标本是孔生胶瘤菌(新拟)(Carcinomyces polyporina),隶属于担子菌门(Basidiomycota)、银耳纲(Tremellomycetes)、银耳目(Tremellales)、胶瘤菌科(新拟)(Carcinomycetaceae)。该物种代表了中国的1个新记录属、种,是该属在东亚地区的首次报道。孔生胶瘤菌寄生于多孔菌类真菌的子实体上,形成胶质状菌瘿,担子纵裂,担孢子可萌发后形成分生孢子。研究标本保存于中国科学院昆明植物研究所标本馆隐花植物标本室,馆藏号为HKAS 115765。     

中国地孔菌属(盘菌目)分类研究

本文报道盘菌目地孔菌属(Geopora Harkn.)我国种类的分类研究成果,共描述4个种即砂生地孔菌(Geopora arenicola(Lév.)Kers),库氏地孔菌(Geopora cooperi Harkn.),叶质地孔菌(Geopora foliacea(Schaef.)Ahmad)和梭椭孢地孔菌(Geopora perprolata B.C.Zhang,sp.nov.)。叶质地孔菌为中国新记录种。文中对各个种给予了详细的描述,并附有分种检索表。     

中国多孔菌科一新记录属——棘刚毛菌属(Echinochaete)

笔者1987年9月8日在吉林省张广才岭老爷岭山采到一份标本,生于阔叶树腐木上,经鉴定为短孔棘刚毛菌(Echinochaete brachyporus)隶属于多孔菌科(Polyporaceae),棘刚毛菌属(Echinochaete)。棘刚毛菌属为多孔菌科中一个较小的属,现已见报道的共有6种1变种,分布于世界许多地区。对于本属及其种类在我国未曾有记载。本文对该属的概况及新记录种的特征、分布作了报导。     

中国硬孔菌属研究小记及一新记录种

总结了我国硬孔菌属的种类.目前该属在我国共发现11种,其中叉囊硬孔菌为中国新记录种.文中对该种进行了详细描述和显微结构绘图,并给出了该属的检索表.     

中国锈革孔菌科新种及值得注意的种

本文报道了产于我国云南西双版纳热带雨林的多孔菌一新种,版纳嗜蓝孢层孔菌 Ｆｏｍｉｔｉｐｏｒｉａ ｂａｎｎａｅｎｓｉｓ Ｙ．Ｃ． Ｄａｉ,该菌具有平伏的子实体较小的担孢子及大量的子实层刚毛这些特征很容易使该新种区别于同属的其它种,对与其它近似种的不同也进行了讨论锈革孔菌科的另外两种悦目小集毛菌Ｃｏｌｔｒｉｃｉｅｌｌａ　 ａｂｌｅｃｔａｂｉｌｉｓ（Ｌｌｏｙｄ） Ｋｏｔｌ, Ｐｏｕｚａｒ＆ Ｒｙｖａｒｄｅｎ和杜氏齿革菌 Ｈｙｄｎｏｃｈａｅｔｅ ｄｕｐｏｒｔｉｉ Ｐａｔ．被报道为中国新记录种,并根据我国的材料对这两种进行了详细描述。三个种被重新进行了组合它们是 Ｆｏｍｉｔｉｐｏｒｉａ ｓｏｎｏｒａ（Ｇｌｉｂ．）Ｙ．Ｃ． Ｄａｉ, Ｆｏｍｉｔｉｐｏｒｉａ　 ｓｕｂｌａｅｖｉｇａｔａ（Ｃｌｅｌａｎｄ　＆ 　Ｒｏｄｗａｙ） Ｙ．Ｃ． Ｄａｉ和 Ｏｎｎｉａ　ｆｌａｏｖｉｄａ（Ｂｅｒｋ．） Ｙ．Ｃ． Ｄａｉ．     

云南剌皮属的研究

本文报道云南剌皮属Heterochaete Pat.10种,其中1个新种,3个国内新纪录种。新种是思茅剌皮H.simaoensis Hu et J.Z.Lisp.nov。本文所研究的标本藏于湖南师范大学真菌标本室(MHHNU)和中国科学院微生物研究所真菌标本室(HMAS)。     

Pat1 contributes to the RNA binding activity of the Lsm1-7–Pat1 complex

A major mRNA decay pathway in eukaryotes is initiated by deadenylation followed by decapping of the oligoadenylated mRNAs and subsequent 5′-to-3′ exonucleolytic degradation of the capless mRNA. In this pathway, decapping is a rate-limiting step that requires the hetero-octameric Lsm1-7–Pat1 complex to occur at normal rates in vivo. This complex is made up of the seven Sm-like proteins, Lsm1 through Lsm7, and the Pat1 protein. It binds RNA and has a unique binding preference for oligoadenylated RNAs over polyadenylated RNAs. Such binding ability is crucial for its mRNA decay function in vivo. In order to determine the contribution of Pat1 to the function of the Lsm1-7–Pat1 complex, we compared the RNA binding properties of the Lsm1-7 complex purified from pat1Δ cells and purified Pat1 fragments with that of the wild-type Lsm1-7–Pat1 complex. Our studies revealed that both the Lsm1-7 complex and purified Pat1 fragments have very low RNA binding activity and are impaired in the ability to recognize the oligo(A) tail on the RNA. However, reconstitution of the Lsm1-7–Pat1 complex from these components restored these abilities. We also observed that Pat1 directly contacts RNA in the context of the Lsm1-7–Pat1 complex. These studies suggest that the unique RNA binding properties and the mRNA decay function of the Lsm1-7–Pat1 complex involve cooperation of residues from both Pat1 and the Lsm1-7 ring. Finally our studies also revealed that the middle domain of Pat1 is essential for the interaction of Pat1 with the Lsm1-7 complex in vivo.     

The 3′ Overhangs at Tetrahymena thermophila Telomeres Are Packaged by Four Proteins,Pot1a,Tpt1, Pat1, and Pat2

Although studies with the ciliate Tetrahymena thermophila have played a central role in advancing our understanding of telomere biology and telomerase mechanisms and composition, the full complement of Tetrahymena telomere proteins has not yet been identified. Previously, we demonstrated that in Tetrahymena, the telomeric 3′ overhang is protected by a three-protein complex composed of Pot1a, Tpt1, and Pat1. Here we show that Tpt1 and Pat1 associate with a fourth protein, Pat2 (Pot1 associated Tetrahymena 2). Mass spectrometry of proteins copurifying with Pat1 or Tpt1 identified peptides from Pat2, Pot1a, Tpt1, and Pat1. The lack of other proteins copurifying with Pat1 or Tpt1 implies that the overhang is protected by a four-protein Pot1a-Tpt1-Pat1-Pat2 complex. We verified that Pat2 localizes to telomeres, but we were unable to detect direct binding to telomeric DNA. Cells depleted of Pat2 continue to divide, but the telomeres exhibit gradual shortening. The lack of growth arrest indicates that, in contrast to Pot1a and Tpt1, Pat2 is not required for the sequestration of the telomere from the DNA repair machinery. Instead, Pat2 is needed to regulate telomere length, most likely by acting in conjunction with Pat1 to allow telomerase access to the telomere.     

The C‐terminal α–α superhelix of Pat is required for mRNA decapping in metazoa

Pat proteins regulate the transition of mRNAs from a state that is translationally active to one that is repressed, committing targeted mRNAs to degradation. Pat proteins contain a conserved N‐terminal sequence, a proline‐rich region, a Mid domain and a C‐terminal domain (Pat‐C). We show that Pat‐C is essential for the interaction with mRNA decapping factors (i.e. DCP2, EDC4 and LSm1–7), whereas the P‐rich region and Mid domain have distinct functions in modulating these interactions. DCP2 and EDC4 binding is enhanced by the P‐rich region and does not require LSm1–7. LSm1–7 binding is assisted by the Mid domain and is reduced by the P‐rich region. Structural analysis revealed that Pat‐C folds into an α–α superhelix, exposing conserved and basic residues on one side of the domain. This conserved and basic surface is required for RNA, DCP2, EDC4 and LSm1–7 binding. The multiplicity of interactions mediated by Pat‐C suggests that certain of these interactions are mutually exclusive and, therefore, that Pat proteins switch decapping partners allowing transitions between sequential steps in the mRNA decapping pathway.     

集毛孔菌属2个中国新记录种(英文)

杜氏集毛孔菌和梨生集毛孔菌是中国新记录种。杜氏集毛孔菌发现于云南中部,生长在石栎树的根部。梨生集毛孔菌发现于湖北和湖南省,生长在阔叶树的林地上。笔者根据采集的材料对这2个种进行了详细的描述和显微结构绘图。     

Structural Insights into the Substrate Specificity of the Rhodopseudomonas palustris Protein Acetyltransferase RpPat: IDENTIFICATION OF A LOOP CRITICAL FOR RECOGNITION BY RpPat*?

Lysine acetylation is a post-translational modification that is important for the regulation of metabolism in both prokaryotes and eukaryotes. In bacteria, the best studied protein acetyltransferase is Pat. In the purple photosynthetic bacterium Rhodopseudomonas palustris, at least 10 AMP-forming acyl-CoA synthetase enzymes are acetylated by the Pat homologue RpPat. All bona fide RpPat substrates contain the conserved motif PX₄GK. Here, we show that the presence of such a motif is necessary but not sufficient for recognition by RpPat. RpPat failed to acetylate the methylmalonyl-CoA synthetase of this bacterium (hereafter RpMatB) in vivo and in vitro, despite the homology of RpMatB to known RpPat substrates. We used RpMatB to identify structural determinants that are recognized by RpPat. To do this, we constructed a series of RpMatB chimeras that became substrates of RpPat. In such chimeras, a short region (11–25 residues) of RpMatB located >20 residues N-terminal to the acetylation site was replaced with the corresponding sequences from other AMP-forming acyl-CoA synthetases that were known RpPat substrates. Strikingly, the enzymatic activity of RpMatB chimeras was regulated by acetylation both in vitro and in vivo. Crystal structures of two of these chimeras showed that the major difference between them and wild-type RpMatB was within a loop region ∼23 Å from the acetylation site. On the basis of these results, we suggest that RpPat likely interacts with a relatively large surface of its substrates, in addition to the PX₄GK motif, and that RpPat probably has relatively narrow substrate specificity.     

Diauxic shift-dependent relocalization of decapping activators Dhh1 and Pat1 to polysomal complexes

Dhh1 and Pat1 in yeast are mRNA decapping activators/translational repressors thought to play key roles in the transition of mRNAs from translation to degradation. However, little is known about the physical and functional relationships between these proteins and the translation machinery. We describe a previously unknown type of diauxic shift-dependent modulation of the intracellular locations of Dhh1 and Pat1. Like the formation of P bodies, this phenomenon changes the spatial relationship between components involved in translation and mRNA degradation. We report significant spatial separation of Dhh1 and Pat1 from ribosomes in exponentially growing cells. Moreover, biochemical analyses reveal that these proteins are excluded from polysomal complexes in exponentially growing cells, indicating that they may not be associated with active states of the translation machinery. In contrast, under diauxic growth shift conditions, Dhh1 and Pat1 are found to co-localize with polysomal complexes. This work suggests that Dhh1 and Pat1 functions are modulated by a re-localization mechanism that involves eIF4A. Pull-down experiments reveal that the intracellular binding partners of Dhh1 and Pat1 change as cells undergo the diauxic growth shift. This reveals a new dimension to the relationship between translation activity and interactions between mRNA, the translation machinery and decapping activator proteins.     

Rickettsia typhi Possesses Phospholipase A2 Enzymes that Are Involved in Infection of Host Cells

The long-standing proposal that phospholipase A₂ (PLA₂) enzymes are involved in rickettsial infection of host cells has been given support by the recent characterization of a patatin phospholipase (Pat2) with PLA₂ activity from the pathogens Rickettsia prowazekii and R. typhi. However, pat2 is not encoded in all Rickettsia genomes; yet another uncharacterized patatin (Pat1) is indeed ubiquitous. Here, evolutionary analysis of both patatins across 46 Rickettsia genomes revealed 1) pat1 and pat2 loci are syntenic across all genomes, 2) both Pat1 and Pat2 do not contain predicted Sec-dependent signal sequences, 3) pat2 has been pseudogenized multiple times in rickettsial evolution, and 4) ubiquitous pat1 forms two divergent groups (pat1A and pat1B) with strong evidence for recombination between pat1B and plasmid-encoded homologs. In light of these findings, we extended the characterization of R. typhi Pat1 and Pat2 proteins and determined their role in the infection process. As previously demonstrated for Pat2, we determined that 1) Pat1 is expressed and secreted into the host cytoplasm during R. typhi infection, 2) expression of recombinant Pat1 is cytotoxic to yeast cells, 3) recombinant Pat1 possesses PLA₂ activity that requires a host cofactor, and 4) both Pat1 cytotoxicity and PLA₂ activity were reduced by PLA₂ inhibitors and abolished by site-directed mutagenesis of catalytic Ser/Asp residues. To ascertain the role of Pat1 and Pat2 in R. typhi infection, antibodies to both proteins were used to pretreat rickettsiae. Subsequent invasion and plaque assays both indicated a significant decrease in R. typhi infection compared to that by pre-immune IgG. Furthermore, antibody-pretreatment of R. typhi blocked/delayed phagosomal escapes. Together, these data suggest both enzymes are involved early in the infection process. Collectively, our study suggests that R. typhi utilizes two evolutionary divergent patatin phospholipases to support its intracellular life cycle, a mechanism distinguishing it from other rickettsial species.