烟草内生菌根真菌的分离鉴定

本文报道了从烟草(Nicotiana tabacum L.)的根际土壤中分离出内生菌根真菌的孢子,用单孢接种烟苗并在温室内水培条件下培养。选出能在烟草上形成菌根的菌株,经过再次单孢接种确认后,进行种的鉴定。从分离的8个菌株中已鉴定出球囊霉属(Glomus)的3个新记录种:漏斗孢球囊霉[G.mosseae(Nic.& Gerd.)GeM.& Trappe]、根内孢球囊霉(G.intraradics Schenck & Smith)和联结球囊霉(G.constrictum Trappe)。     

中国毁丝霉属嗜热型真菌两新记录种

对在山东、陕西及云南采集的标本进行了研究 ,鉴定出毁丝霉属 (MyceliophthoraCost)中的 2个嗜热型真菌新记录种 ,即弗格斯毁丝霉 [M .fergusii(vanKlopotek)vanOorschot]和嗜热毁丝霉 [M .thermophila (Apinis)vanOorschot],并对其进行了描述和讨论。凭证标本保存在山东农业大学植物病理学标本室 (HSAUP)。     

我国北部的七种VA菌根真菌

从北京和新疆地区某些栽培及野生植物根际分离出7种VA真菌:丽孢无梗囊霉Acaulospora elegans Trappe & Gerd.,地表球囊霉Glomus versiforme (karsten) Berch,隐球囊霉G.occultum Walker,透光球囊霉G.diaphanum Morton & Walker,摩西球囊霉G.mosseae(Nicol.& Gerd.)Gerd.& Trappe,缩球囊霉G.constrictum Trappe,和苏格兰球囊霉G.caledonium(Nicol.& Gerd.)Trappe & Gerd.。其中,地表球囊霉为我国新记录种。本文除描述其形态特征外,还介绍了孢壁组织化学反应及生境条件。     

红壤中VA菌根真菌(球囊霉目)的种类和生态分布

本文报道了发育于第四纪红色粘土母质上的红壤中的4属13种VA菌根真菌(球囊霉目):1.细齿无梗囊霉 Acaulospora denticulata Sieverding & Toro;2.丽孢无梗囊霉Acaulospora elegans Trappe & Gerdemann:3.光壁无梗囊霉Acaulospora laevis Gerdeman D & Trappe:4.巨大巨孢囊霉Gigaspora gigantea(Nicol.& Gerd.)Gerdemann & Trappe;5.珍珠巨孢囊霉Gigaspora margarita Becket & Hall;6.聚球囊霉Glomus aggregatum Schenck & Smith;7.明球囊霉Glomus clarum Nicolson & Schenck;8.集球囊霉Glomus fasiculatum(Thaxter)Gerdemann & Trappe;9.地球囊霉Glomus geosporum(Nicol.& Gerd.)Walker;10.木薯球囊霉Glomus manihot Howeler,Sieverding & Schenck;11.变形球囊霉Glomus versiforme(Karsten)Berch;12.美丽盾孢囊霉Scutellospora calospora(Nicol.& Gerd.)Walker & Sanders;13.异配盾孢囊霉Scutellospora heterogama(Nicol.& Gerd.)Walker & Sanders。其中细齿无梗囊霉(Acaulospora denticulata)、巨大巨孢囊霉(Gigaspora gigantea)、木薯球囊霉(Glomus manihot)和异配盾孢囊霉(Scutellospora heterogama)4种为国内新记录种。对这13种VA菌根真菌的形态进行了描述讨论,并对这些种群的出现频度、不同利用方式     

我国北部的八种VA菌根真菌

本文为继“我国北部的七种VA菌根真菌”之后的续篇,报道了从北京、新疆和吉林分离的八个种:细凹无梗囊霉Acaulospora scrobiculata Trappe,蜜色无梗囊霉A.mellea Spain& Schenck,稍长无梗囊霉A.longula Spain & Schenck,近明球囊霉Glomus claroideumSchenck & Smith,集球囊霉G.fasciculatum(Thaxter)Gerd.& Trappe,emend.Walker& Koske,地球囊霉G.geosporum(Nicol.& Gerd.)Walker,何氏球囊霉G.hoi Berch &Trappe,根内球囊霉G.intraradix Schenck & Smith。其中,细凹无梗囊霉、蜜色无梗囊霉、稍长无梗囊霉和何氏球囊霉等4个为我国新记录种。本文报道了上述8种的形态特征描述、孢壁组织化学反应及生境状况。     

茎点霉和叶点霉两属的新种及国内新记录种

本文对采自东北地区的115份茎点霉(Phoma)和叶点霉(Phyllosticta)的标本进行分类研究,有新种2个和国内新记录种9个。新种是木瓜生叶点霉(Phyllosticta chaenomelesicola L.Yu et Bai)和草玉铃生叶点霉(Phyllosticta convallaricola L.Yu et Bai)。新种有拉丁文和汉文描述及图。对新记录种作了简要介绍。模式标本保存于沈阳农业大学植保系真菌标本室(HMSAU)。     

腔孢纲一新属——类腊肠茎点霉属

近年甘肃省河西走廊一带胡萝卜上发生一种叶斑病,严重时造成减产20%~30%。其病原物为丝分孢子真菌(半知菌)腔孢纲Coelomycetes中一未描述的真菌。该菌具有分生孢子器,但其形态与相似属茎点霉属Phoma、鞘茎点霉属Coleophoma和拟腊肠茎点霉属Allantophomopsis不同,遂建立类腊肠茎点霉属Allantophomoides(新属);其模式种为胡萝卜类腊肠茎点霉Allantophomoidescarotae(新种)。研究的标本保存在山东农业大学植物病理学标本室(HSAUP)。     

中国一新记录属—双聚散霉属(英文)

文中详细描述和报道了来自山东省沂源县沂山土壤中的一个中国新记录属—双聚散霉属(Dicyma Boulanger)和中国新记录种—青褐双聚散霉[Dicyma olivacea(Emoto & Tubaki)von Arx]。     

海南红树林生境中海疫霉种的分离与鉴定*

从海南琼山市东寨港红树林区、文昌市清澜港红树林区、三亚市红树林区落叶病斑上采集分离到15个海生疫霉菌株,经鉴定分属于二个海生疫霉菌种,其中11个菌株属泡囊海疫霉Halophytophthora vesicula (Anastasiou & Churchland) Ho & Jong,4个菌株属刺囊海疫霉圆裂变种Halophytophthora spinosa var. lobata (Fell & Master) Ho & Jong, 这两个种均属国内新纪录种。     

腔孢纲一新属--类腊肠茎点霉属

近年甘肃省河西走廊一带胡萝卜上发生一种叶斑病,严重时造成减产20%~30%.其病原物为丝分孢子真菌(半知菌)腔孢纲Coelomycetes中一未描述的真菌.该菌具有分生孢子器,但其形态与相似属茎点霉属Phoma、鞘茎点霉属Coleophoma和拟腊肠茎点霉属Allantophomopsis不同,遂建立类腊肠茎点霉属Allantophomoides(新属);其模式种为胡萝卜类腊肠茎点霉Allantophomoides carotae(新种).研究的标本保存在山东农业大学植物病理学标本室(HSAUP).     

Five new species of Eimeria Schneider, 1875 from the endangered Tibetan antelope Pantholops hodgsonii (Abel) (Artiodactyla: Bovidae: Caprinae) in the Hoh Xil Nature Reserve Area of Qinghai Province,China

We examined faeces of 76 endangered Tibetan antelopes Pantholops hodgsonii (Abel) in May 2017, from the Hoh Xil Nature Reserve, Qinghai Province, China, and found 62/76 (82%) discharging oöcysts representing five new species of Eimeria Schneider, 1875. Oöcysts of Eimeria pantholopensis n. sp., found in 54/76 (71%) chiru, are subspheroidal/ellipsoidal, 15–22 × 12–19 (18.6 × 16.1) µm, with a length/width (L/W) ratio of 1.0–1.3 (1.2); micropyle cap and 1–3 polar granules are present, but oöcyst residuum is absent. Sporocysts are ovoidal, 7–11 × 4–6 (9.2 × 5.3) µm, with a L/W ratio of 1.6–2.0 (1.7); Stieda body and sporocyst residuum of small, scattered granules are present; each sporozoite contains 2 refractile bodies. Oöcysts of Eimeria wudaoliangensis n. sp. found in 52/76 (68%) chiru, are pyriform, 21–29 × 17–21 (24.9 × 19.0) µm, with a L/W ratio of 1.1–1.5 (1.3); micropyle, micropyle cap and 1–4 polar granules are present, but oöcyst residuum is absent. Sporocysts are ovoidal, 9–13 × 5–8 (11.7 × 6.7) µm, with a L/W ratio of 1.4–2.7 (1.7); Stieda body and sporocyst residuum of disbursed granules are present; sporozoites have a single large refractile body. Oöcysts of Eimeria hodgsonii n. sp. found in 20/76 (26%) chiru, are elongate-ellipsoidal, 25–32 × 18–21 (28.9 × 19.8) µm, with a L/W ratio of 1.2–1.7 (1.5); micropyle, micropyle cap and 1–3 polar granules are present, but oöcyst residuum is absent. Sporocysts are ovoidal, 11–14 × 6–7 (12.3 × 6.8) µm, with a L/W ratio of 1.7–2.1 (1.8); Stieda body and sporocyst residuum as group of large granules lying along the interface between intertwined sporozoites are present; sporozoites have 2 refractile bodies. Oöcysts of Eimeria schalleri n. sp. found in 49/76 (64.5%) chiru, are ellipsoidal, 26–36 × 19–25 (30.4 × 23.2) µm, with a L/W ratio of 1.2–1.5 (1.3); micropyle with micropyle cap and polar granules appearing as many diffuse tiny bodies are present, but oöcyst residuum is absent. Sporocysts are ovoidal, 12–16 × 7–9 (14.2 × 7.8) µm, with a L/W ratio of 1.6–2.1 (1.8); Stieda body and sporocyst residuum are present, the latter as a group of small dispersed granules between intertwined sporozoites; sporozoites with 2 refractile bodies. Oöcysts of Eimeria sui n. sp. found in 4/76 (5%) chiru, are ovoidal, 32–38 × 26–30 (36.6 × 28.6) µm, with a L/W ratio of 1.0–1.4 (1.3); micropyle and micropyle cap and 1–3 polar granules are present, but oöcyst residuum is absent. Sporocysts are ovoidal, 15–18 × 8–10 (16.7 × 8.9) µm, with a L/W ratio of 1.7–2.1 (1.9); Stieda body and sporocyst residuum are present, the latter as a group of dispersed small granules; sporozoites with 2 refractile bodies. Five of 62 faecal samples in which oöcysts were detected (8%) had a single species infection, 13 of 62 (21%) had two species, 28 of 62 (45%) had three species and 16 of 62 (26%) had four species.

     

Relationship between the Interhelical Packing Angles and the Length of α-Helices in Proteins

Abstract—Mutual arrangement, or packing, of α-helices in proteins depends on several factors, but, tight packing and the chemical nature of the polypeptide chain are the most important. This study shows, for the first time, that the torsion packing angles between axes of α-helices depend on their length. A database of helical pairs formed by two connected and juxtaposed α-helices has been compiled using the Protein Data Bank. These helical pairs have been subdivided into four types: (1) 10474 pairs formed by long helices; (2) 3665 pairs in which the first α-helix is long and the second is short; (3) 3648 pairs in which the first α‑helix is short and the second is long; 4) 1895 pairs in which both helices are short. Analysis of the database showed that most helical pairs in which both the helices are long form α-hairpins having interhelical packing angles of Ω ≈ 20°. Most helical pairs in which one α-helix is long and the other is short or both helices are short form αα-corners having orthogonal (Ω ≈ –70°…–90°) or slanted (Ω ≈ –50°) packing of α-helices. The possible reasons for this relationship between interhelical angles (Ω) and the length of α-helices are discussed. These results are of great importance in protein modeling and prediction since they enable the determination of the mutual arrangement of α-helices in protein molecules.     

Two new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from skinks in Florida

Eimeria egregia n. sp. parasitises the gall-bladder of Eumeces egregius onocrepis, the brown red-tailed skink, in the Ocala National Forest, Marion County, Florida. Oöcysts are oval, 27.6 × 17.4 µm (25–32 × 16–20), without micropyle, polar body or oöcyst residuum. The oöcyst length/width ratio is 1.59 (1.42–1.76). Sporocysts are ovoid, 10.3 × 8.3 µm (8.5–12 × 7–9 µm), with a length/width ratio of 1.24 (1.06–1.50,), without a Stieda body, but with a prominent sporocyst residuum. Sporozoites are 10–12 × 2.5–3 µm. The ground skink Scincella lateralis is infected by Eimeria scincellae n. sp. The oöcysts are cylindrical, 29.8 × 15.9 µm (28–33 × 14–17), with no micropyle, polar body or oöcyst residuum. The oöcyst length/width ratio is 1.89 (1.68–2.14). Sporocysts are oval, 10.9 × 8.0 µm (9.5–12 × 7–9), with a length/width ratio of 1.36 (1.18–1.64,), no Stieda body and a prominent sporocyst residuum. Sporozoites are 9–11 × 2–2.5 µm.     

Description of the oöcysts of three new species of coccidia (Apicomplexa: Eimeriidae) from lizards in Namibia

Three new species of coccidian were recovered from the intestinal contents and faeces of lizards in Namibia, southwest Africa. Oöcysts of Eimeria barnardi n. sp. are described from Rhoptropus barnardi (Gekkonidae) and are ellipsoidal, 24.3 × 19.9 (21–26.5 × 16–22) m; shape index (length/width) 1.22 (1.12–1.30). A micropyle and oöcyst residuum are absent but a fragmented polar granule is present. Sporocysts are subspherical, 9.2 × 8.3 (8–11 × 7.5–9) m; shape index 1.11 (1.02–1.27). Oöcysts of Eimeria pachybibroni n. sp. were found in Pachydactylus bibroni (Gekkonidae) and are ellipsoidal, 26.2 × 18.2 (21.5–28 × 16–19) m; shape index 1.44 (1.30–1.52). A micropyle and oöcyst residuum are absent but a polar granule is present. Sporocysts are subspherical, 8.9 × 8.0 (8–9.5 × 7–8.5) m; shape index 1.12 (1.03–1.20). Oöcysts of Isospora spilogaster n. sp. are reported from Mabuya spilogaster (Scincidae) and are subspherical, 27.4 × 26.0 (21.5–35 × 21–35) m; shape index 1.05 (1.00–1.13). Micropyle, oöcyst residuum and polar granules are absent. Sporocysts are ellipsoidal, 13.2 × 9.7 (10.5–15 × 9–11) m; shape index 1.36 (1.08–1.50).     

Coccidian parasites (Apicomplexa: Eimeriidae) of the endemic Florida snake Tantilla relicta Telford (Serpentes: Colubridae)

The endemic Florida snake Tantilla relicta Telford is parasitised by six species of coccidia. Caryospora tantillae n. sp. has nearly spherical oöcysts, 19.6 × 18.9 µm (16–22 × 16–21), with no polar body, and an oöcyst length/width ratio (shape index, SI) of 1.04 (1.00–1.11). Ovoidal sporocysts are 15.1 × 11.6 µm (12–17 × 10–13), with an SI of 1.30 (1.1–1.6), a single prominent Stieda body and a sporocyst residuum. Sporozoites are 14 × 2.5 µm. Caryospora relictae n. sp. also has nearly spherical oöcysts, 18.5 × 17.6 µm (16–22 × 15–20), but is distinguished by having a distinct polar body and a substieda body in sporocysts. The oöcyst SI is 1.05 (1.0–1.2). Sporocysts are ovoidal, 14.8 × 11.4 µm (12–17 × 10–16), with an SI of 1.29 (1.1–1.5) and a sporocyst residuum. Sporozoites are 10–14 × 2–2.5 µm. Isospora cf. wilsoni has ovoidal to spherical oöcysts without a micropyle, measure 17.4 × 17.1 µm (15–19 × 15–19), and have an SI of 1.02 (1.00–1.07). Oöcysts have no polar granule or oöcyst residuum. Sporocysts are ovoidal, 11.4 × 8.2 µm (9–14 × 7–10), with an SI of 1.39 (1.18–1.62). Both a Stieda body and sporocyst residuum are present, but a substieda body, characteristic of I. wilsoni as described, was not observed. Sporozoites are 7–8 × 2.5–3 µm. An Eimeria sp., of which the sample was too small to justify taxonomic designation, has nearly spherical oöcysts without micropyle, a size of 22.5 × 20.9 µm (22–23 × 20–22), an SI of 1.08 (1.00–1.12) and no polar granule. Sporocysts measure 12.5 × 8.9 µm (11–14 × 7–11) and have an SI of 1.44 (1.18–1.87), a sporocyst residuum and no Stieda body. Sporozoites are 13 × 5 µm. Eimeria amphorae n. sp. has ovoidal to spherical oöcysts without a micropyle, a size of 24.8 × 22.3 µm (23–27 × 20–26), an SI of 1.12 (1.02–1.25) and no polar granule or oöcyst residuum. Sporocysts are elongate, 18.4 X 8.0 µm (17-22 × 6-9.5), with an SI 2.33 (1.79–3.00) and no discernible Stieda body or sporocyst residuum. Sporocyst shape differs by orientation, rectangular to amphora-like, tapering abruptly to a blunt point; sporozoites large, 15.5 × 4.2 µm. A biliary parasite, Eimeria pleistocenensis n. sp., has ovoidal to elongate oöcysts, without micropyle, with a size of 27.8 × 19.4 µm (23–32 × 14–23), with an SI of 1.44 (1.17–1.82) and an oöcyst residuum but no polar granule. Sporocysts ovoidal, 10.7 × 8.6 (9–13 × 8–10), with an SI of 1.24 (1.05–1.37), a sporocyst residuum, but without Stieda body; sporozoites 8.8 × 2.7 µm. Similar oöcysts from other Tantilla relicta populations, T. relicta neilli in north Florida T. relicta pamlica in southeastern Florida and T. relicta relicta in south-central Florida, have dimensions that lie within the range of variation in the type population and identically shaped sporocysts that suggest conspecificity with E. pleistocenensis, and presence of the species in the precursor to Tantilla relicta prior to the second interglacial period.     

Four new spider species of the family Theridiosomatidae (Arachnida,Araneae) from caves in Laos

Four new species of the spider family Theridiosomatidae are described from caves in Laos: Alaria cavernicola sp. n. (♂♀), A. navicularis sp. n., (♂♀) A. bicornis sp. n. (♂♀), Chthonopes thakekensis sp. n. (♀). Diagnoses and illustrations for all new taxa are given. All holotypes are deposited in the Senckenberg Research Institute in Frankfurt am Main, Germany (SMF).     

Helix-helix transitions in DNA: fibre X-ray study of the particular cases poly(dG-dC) · poly(dG-dC) and poly(dA) · 2poly(dT)

The helix-helix transitions which occur in poly(dG-dC) · poly(dG-dC) and in poly (dG-m⁵dC) · poly(dG-m⁵dC) are commonly assumed to be changes between the right-handed A- or B-DNA double helices and the left-handed Z-DNA structure. The mechanisms for such transconformations are highly improbable, especially when they are supposed to be active in long polynucleotide chains organised in semicrystalline fibres. The present alternative possibility assumes that rather than the Z-DNA it is a right-handed double helix (S-DNA) which actually takes part in these form transitions. Two molecular models of this S form, in good agreement with X-ray measurements, are proposed. They present alternating C(2′)-endo and C(3′)-endo sugar puckering like the “alternating B-DNA” put forward some years ago. Dihedral angles, sets of atomic coordinates and stereo views of the two S-DNA structures are given, together with curves of calculated diffracted intensities. Furthermore, we question the possibility of obtaining semicrystalline fibres with triple helices of poly(dA) · 2poly(dT) in a way which renders X-ray diffraction efficient. It is suggested that, up to now, only double helices of poly(dA) · poly(dT) can actually be observed by fibre X-ray diffraction measurements. Received: 30 March 1999 / Revised version: 30 June 1999 / Accepted: 30 June 1999     

Biogenic Origin of Polymetallic Nodules from the Clarion-Clipperton Zone in the Eastern Pacific Ocean: Electron Microscopic and EDX Evidence

Polymetallic/ferromanganese nodules (Mn-nodules) have been assigned a huge economic potential since they contain considerable concentrations of manganese, copper, nickel, iron, and cobalt. It has been assumed that they are formed by, besides hydrogenous, nonbiogenic processes, biogenic processes based on metabolic processes driven by microorganisms. In the present study, we applied the techniques of digital optical microscopy and high-resolution scanning electron microscopy to search for microorganisms in Mn-nodules. They were collected from the Clarion-Clipperton Zone in the Eastern Pacific Ocean and are composed of Mn (23.9%), Cu (0.69%), Ni (1.02%), Fe (10.9%), and Co (0.29%). These Mn-nodules, between 2.3 and 4.8 cm, show a distinct lamination; they are composed of small-sized micronodules, 100 to 450 μm in size, which are bound together by an interstitial whitish material. In the micronodules, a dense accumulation of microorganisms/bacteria could be visualized. Only two morphotypes exist: (1) round-shaped cocci and (2) elongated rods. The cocci (diameter: ≈3.5 μm) are arranged in bead-like chains, while the rods (≈2 × 0.4 μm) are arranged either as palisades or in a linear row. Energy-dispersive X-ray spectroscopy analyses showed that the areas rich in microorganisms/bacteria are also rich in Mn, while in regions where no microorganisms are found, the element Si is dominant. We suggest that growth of the Mn-nodules starts with the formation of “micronodules.” The formation of micronodules is assumed to be mediated by microorganisms. After accretion of biogenic and additional nonbiogenic minerals, the micronodules assemble to large nodules on the sea floor through additional inclusion of nonbiogenic material.     

Evolution and differential expression of the (1→3)-β-glucan endohydrolaseencoding gene family in barley, Hordeum vulgare

The (1→3)-β-d-glucan glucanohydrolases [(1→ 3)-GGH; EC 3.2.1.39] of barley (Hordeum vulgare L., cv Clipper) are encoded by a small gene family. Amino acid sequences deduced from cDNA and genomic clones for six members of the family exhibit overall positional identities ranging from 44% to 78%. Specific DNA and oligodeoxyribonucleotide (oligo) probes have been used to demonstrate that the (1→3)-GGH-encoding genes are differentially transcribed in young roots, young leaves and the aleurone of germinated grain. The high degree of sequence homology, coupled with characteristic patterns of codon usage and insertion of a single intron at a highly conserved position in the signal peptide region, indicate that the genes have shared a common evolutionary history. Similar structural features in genes encoding barley (1→3,1→4)-β-glucan 4-glucanohydrolases [(1→3,1→4)-GGH; EC 3.2.1.73] further indicate that the (l→3)-GGHs and (l→3,1→4)-GGHs are derived from a single ‘super’ gene family, in which genes encoding enzymes with related yet quite distinct substrate specificities have evolved, with an associated specialization of function. The (1→3,1→4)-GGHs mediate in plant cell wall metabolism through their ability to hydrolyse the (1→3,1→4)-β-glucans that are the major constituents in barley walls, while the (1→3)-GGHs, which are unable to degrade the plant (1→3,1→4)-β-glucans, can hydrolyse the (1→3)- and (1→3,1→6)-β-glucans of fungal cell walls.