西藏扎布耶盐碱湖细菌的多样性与分离菌株的生长特性

【背景】扎布耶湖位于青藏高原地区,是以水体中富含高浓度CO₃²⁻、HCO₃⁻和Na⁺为显著特性的盐碱湖,因其地理位置高寒、高海拔,人迹罕至,涉及该盐湖微生物的研究相对较少。【目的】系统探究湖水中细菌多样性和菌种资源等,发掘可利用的潜在菌种。【方法】采用Illumina测序16S rRNA基因V3−V4区分析扎布耶湖细菌的群落结构组成、物种多样性特征;采用纯培养筛选分离可培养细菌,明确分离菌株分类学地位、生长特性及产酸能力,同时测定分离菌株四氢嘧啶(ectoine)、吲哚乙酸(3-indoleacetic acid, IAA)和胞外聚合物(extracellular polymeric substances, EPS)的积聚量。【结果】Illumina测序明确分类地位的细菌有21门44纲86目583属,其中优势门类群是变形菌门(Proteobacteria, 25.11%−67.60%)、拟杆菌门(Bacteroidetes, 4.84%−35.02%)和厚壁菌门(Firmicutes, 1.24%−11.01%),优势属类群是克雷伯氏菌属(Klebsiella, 0.01%−9.53%)、盐单胞菌属(Halomonas, 0.54%−8.75%)、芽单胞菌属(Gemmatimonas, 2.39%−6.00%)和腈基降解菌属(Nitriliruptor, 1.27%−6.26%)。纯培养法筛选获得嗜盐碱菌38株,其中芽孢杆菌属(Bacillus) 23株(60.53%)和盐单胞菌属(Halomonas) 10株(26.32%),菌株均具有耐盐碱和产酸能力(19.80%−29.68%)。大多数菌株能积聚四氢嘧啶、IAA和EPS,产量范围分别为1.36−175.59、0.27−8.69和0.02−0.22 g/g。【结论】扎布耶湖细菌群落结构与其他地区盐碱湖相似,但存在大量未明确分类学地位的细菌,分离菌株多具有耐盐碱及产酸特性。此外,还发现4株高效生产四氢嘧啶、3株生产吲哚乙酸和3株生产胞外聚合物的潜力菌株,为扎布耶盐湖微生物资源的开发利用奠定了基础。     

镉对一株深色有隔内生真菌生长、矿质营养与草酸分泌的影响

【背景】深色有隔内生真菌(dark septate endophyte,DSE)广泛定殖于镉(Cd)污染生境的植物根系,具有增强植物镉耐性的重要生态功能,但人们关于DSE对镉胁迫的生理响应的了解有限。【目的】研究一株DSE嗜鱼外瓶霉(Exophiala pisciphila)对镉胁迫的矿质营养与低分子量有机酸分泌的响应。【方法】采用液体培养法,研究不同浓度(0、25、50、100、200、400 mg/L)镉胁迫对DSE菌丝生长、矿质元素(氮、磷、钾、硫、镁、铁、钙)与镉含量、草酸分泌的影响。【结果】随着镉胁迫浓度增加,菌丝生物量显著下降,降幅为22.8%−90.6%,菌丝的氮、钾和铁含量分别减少26.0%−52.8%、53.8%−92.9%和12.8%−34.3%,而磷、镁和钙含量分别增加15.4%−111.4%、20.4%−31.4%和35.1%−62.5%,硫含量在100 mg/L镉胁迫时增加25.1%。镉胁迫还导致培养液pH值下降,草酸浓度及单位菌丝草酸分泌量显著增加。相关分析发现,菌丝镉含量与硫呈显著负相关(P<0.05),与菌丝钾含量呈极显著负相关(P<0.01),与草酸分泌量呈极显著正相关(P<0.01)。【结论】镉胁迫显著抑制DSE的生长,改变矿质元素的吸收,促进草酸分泌。     

丝状真菌Podospora anserina中光敏色素基因的鉴定及功能分析

光敏色素在细菌和植物发育中起着关键作用,但它们在真菌中的生物学功能尚不完全清楚。【目的】探究光敏色素基因PaPhy1和PaPhy2在Podospora anserina有性生殖和无性发育中的作用及其调控机制。【方法】利用同源重组方法对P.anserina中2个光敏色素基因PaPhy1和PaPhy2进行定点敲除,获得光敏色素基因缺失菌株ΔPaPhy1和ΔPaPhy2,并通过遗传杂交构建双重突变体ΔPaPhy1ΔPaPhy2;分析突变型菌株和野生型菌株在不同光照下有性生殖、无性发育、生长速率和活性氧代谢等方面的差异,明确光敏色素基因在P.anserina中的主要功能。【结果】白光和蓝光诱导P.anserina子实体的形成,ΔPaPhy在光照下产生子实体的数量减少,ΔPaPhy的生命周期延长。【结论】光敏色素基因与P.anserina有性生殖密切相关;ΔPaPhy的衰老延迟和活性氧代谢有关。本研究的结果为进一步探索光照对丝状真菌繁殖调控机制以及抗衰老研究提供了新的思路。     

蔗根土天牛高致病力绿僵菌菌株的生物学特性研究

【目的】明确对蔗根土天牛Dorysthenes granulosus具有良好杀虫活性的金龟子绿僵菌Metarhizium anisopliae JC002菌株生长和产孢所需要的最适营养条件和环境条件。【方法】通过单因素试验,测试了不同培养基、碳源、氮源、温度、pH及紫外线照射不同时间对JC002菌株生长和产孢的影响。【结果】JC002菌株培养基的最佳配方是葡萄糖30 g、蛋白胨15 g、马铃薯200 g、琼脂20 g、水1 000 mL;蔗糖、NaNO3是菌落生长及产孢的最适碳源和氮源;菌株培养的最适温度为25℃,培养基的最适pH值为7.0;紫外光对菌株的生长速率无显著影响,但对产孢量有较大的抑制作用,紫外光照射时间越长,产孢越少。【结论】本研究为JC002菌株的大量培养及其孢子制剂的大量生产和有效利用奠定基础。     

海南近海水域产碱性蛋白酶菌株的分离筛选及发酵条件优化

【背景】微生物蛋白酶在工业生物技术上具有广阔的应用前景。在微生物蛋白酶中,碱性蛋白酶占全球酶总产量的50%以上,获取产碱性蛋白酶的新微生物资源意义重要。【目的】在海南近海贝类养殖基地海泥中筛选获得高产碱性蛋白酶的菌株,对其生长特性进行探究并优化菌株产酶条件,获得新的蛋白酶生产资源。【方法】以酪素培养基为筛选培养基,采用形态学结合系统发育分析鉴定菌株,通过响应面实验优化菌株的产酶条件。【结果】筛选获得一株高产碱性蛋白酶的菌株F3,鉴定为粘质沙雷氏菌（Serratia marcescens）。菌株在最优产酶条件下发酵酶活达到（339.36±4.30） U/mL。【结论】筛选获得的菌株粘质沙雷氏菌F3有较好的产碱性蛋白酶的能力。     

新生隐球菌一个新的产孢相关蛋白Srp1的鉴定与功能分析

【目的】研究产孢相关蛋白Srp1在新生隐球菌有性产孢和致病性中的作用及机理。【方法】采用基因枪转化技术构建新生隐球菌SRP1基因缺失突变体及其互补菌株,并通过小鼠致病性实验和菌株交配实验检测Srp1在新生隐球菌有性产孢和致病性中的作用。【结果】与野生型菌株相比,srp1Δ突变体小鼠致病性无差异;srp1Δ突变体能够交配并形成双核菌丝,但丧失产生担孢子的能力;初步机理分析表明srp1Δ突变体交配后其减数分裂过程被阻断,从而导致srp1Δ突变体不能产生担孢子。【结论】产孢相关蛋白Srp1不影响新生隐球菌的致病性,但可通过调控减数分裂过程影响新生隐球菌的有性生殖。     

余甘子采后软腐病菌的分离鉴定及其细胞壁水解酶活性

【背景】药食同源的余甘子果实在采后贮藏过程中极易软腐变质,严重影响其品质和经济价值。【目的】明确引起余甘子果实软腐病的病原菌种类及其生长特性和产细胞壁水解酶活性,为余甘子采后软腐病的控制及延长其贮藏期奠定基础。【方法】采用组织块分离法从采后发病的余甘子果实分离病原菌,按照科赫法则确定分离菌株的致病性;采用形态学特征结合rDNA-ITS序列分析对病原菌进行鉴定,测定病原菌菌丝生长和产孢特性,检测产胞外细胞壁水解酶活性。【结果】从具有软腐症状的余甘子果实中分离得到32株真菌,其中菌株DQ23是余甘子采后软腐病的致病菌,通过形态特征结合rDNA-ITS序列将其鉴定为Penicillium choerospondiatis。其菌丝在酵母膏葡萄糖琼脂培养基(YDA)上生长最快,在马铃薯蔗糖琼脂培养基(PSA)上产孢最多。该菌能有效利用多种碳、氮源,适宜产孢的碳源为蔗糖、葡萄糖,氮源为蛋白胨、牛肉膏、酵母膏。菌丝生长的最适温度和pH范围分别为25°C和3.0-5.0,产孢的最适温度和pH范围分别为25°C和4.0-7.0。光照均利于菌丝生长和产孢。该菌具有分解果胶、纤维素的能力,无分解蛋白质、鞣质的能力。【结论】Penicillium choerospondiatis是余甘子果实软腐病的病原菌,研究结果为该病害的防控奠定了基础。     

柑桔全爪螨高致病力菌株芽枝状枝孢霉的生物学特性研究

【目的】明确柑桔全爪螨Panonychus citri(Mc Gregor)高致病力菌株芽枝状枝孢霉Cladosporium cladosporioides(CQBBW3)的生物学特性。【方法】通过单因素试验,测试了不同培养基、碳源、氮源、温度及pH对CQBBW3菌株生长和产孢的影响。【结果】CQBBW3菌株的LC50为4.66×108个孢子/m L,LT50为6.2353 d。最佳生长培养基是淀粉琼脂培养基,最适产孢培养基为察氏培养基;菌丝生长最适碳源和氮源为甘露醇和甘氨酸,产孢最适碳源和氮源为乳糖和赖氨酸;最适生长温度为25℃,最适产孢温度为15℃和30℃;最适生长pH值为6.0~8.0,最适产孢pH值7.0。【结论】CQBBW3菌株对柑桔全爪螨有较好的杀虫活性,喜好25℃、中性、富含有机营养的环境。本研究为菌株快速培养及其真菌杀虫制剂的开发与田间应用奠定基础。     

分离菌株DT-08C的鉴定及其除草活性和对作物的安全性

【背景】猪殃殃为作物田的主要恶性杂草之一,目前的防除仍以化学方法为主,对人体和环境造成严重危害。微生物除草剂具有靶标性强、对环境安全等优点,对发展新型农业现代化具有重要的现实意义。【目的】筛选无污染、无危害、强除草的生防菌株,为微生物除草剂提供新的菌种资源。【方法】通过组织分离法分离纯化菌株,采用孢子悬浮液测定菌株除草活性和安全性,运用核糖体内转录间隔区(internaltranscribedspacer,ITS)和转录延伸因子(EF-1α,EF-1/EF-2)基因鉴定,并通过MEGA7.0软件构建系统发育树,最后通过菌落直径和菌丝干重结合血球记数法分析菌株适宜生长和产孢的环境条件。【结果】经分离纯化筛选获得一株菌,命名为DT-08C。经形态学特征和rDNAITS序列分析,分离菌株DT-08C鉴定为芍药镰刀菌(Fusariumpaeoniae),命名为Fusarium paeoniae DT-08C。该分离菌株对猪殃殃的致病率达到47.22%-93.93%,对蚕豆、豌豆、玉米、白菜、番茄、黄瓜和辣椒安全。最适菌落生长和产孢的培养基分别为PSA和燕麦片培养基。【结论】菌株DT-08C对猪...     

蝉拟青霉LB菌株的生物学特性

本文研究碳源、氮源、温度、湿度、pH值和光照等对蝉拟青霉LB菌株生长、产孢和孢子萌发的影响.结果表明,适合该菌株菌落生长和产孢的最佳碳源是可溶性淀粉和蔗糖,最佳氮源为蛋白胨;菌丝生长和孢子萌发的最适温度范围是25℃～27℃,产生分生孢子的最适温度是25℃;分生孢子萌发所需湿度范围是RH 90%～100%,当RH低于90%时很难萌发;在pH值4～10的范围内该菌能生长和产孢,菌丝生长最适pH为6,产生分生孢子和孢子萌发最适pH范围为6-7;光照处理对该菌产孢有一定的影响;分生孢子的致死条件为55℃ 10min.生物学特性显示,蝉拟青霉LB菌株是一株对营养要求不高、对环境适应能力较强的昆虫病原真菌.     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Molecular phylogeny of Phebalium (Rutaceae: Boronieae) and related genera based on the nrDNA regions ITS 1+2

Parsimony analyses of the internal transcribed spacer regions of nuclear ribosomal DNA (ITS 1 & ITS 2) for 38 taxa sampled from the Phebalium group (Rutaceae: Boronieae) and two outgroups confirm that, with the exception of Phebalium sensu stricto and Rhadinothamnus, six of the currently recognised genera within the group are monophyletic. The data indicate that Phebaliums. str. is paraphyletic with respect to Microcybe, and Rhadinothamnus is paraphyletic with respect to Chorilaena. Rhadinothamnus and Chorilaena together are the sister group to Nematolepis. Drummondita, included as an outgroup taxon, clustered within the ingroup as sister to Muiriantha and related to Asterolasia.The phylogeny suggests that the evolution of major clades within a number of these genera (e.g. Phebalium) relates to vicariance events between eastern and south-western Australia. Leionema is an eastern genus, with the most basal taxon being the morphologically distinct Leionema ellipticum from northern Queensland. Leionema also includes one species from New Zealand, but this species (as with some others) proved difficult to sequence and its phylogenetic position remains unknown. Taxonomic changes at the generic level are recommended.The authors wish to thank Paul G.Wilson, PERTH, for advice and discussion, and Paul Forster, BRI, for collecting and providing material of Leionema ellipticum. The project was supported by a Melbourne University Postgraduate Award (to BM), the Australian Biological Resources Study (ABRS), Australian Systematic Botany Society and Wolf Den (Australia) Investments.     

Tracking down the "head blob": comparative analysis of wingless expression in the developing insect procephalon reveals progressive reduction of embryonic visual system patterning in higher insects

The evolution of larval head morphology in holometabolous insects is characterized by reduction of antennal appendages and the visual system components. Little insight has been gained into molecular developmental changes underlying this morphological diversification. Here we compare the expression of the segment polarity gene wingless (wg) in the pregnathal head of fruit fly, flour beetle and grasshopper embryos. We provide evidence that wg activity contributes to segment border formation, and, subsequently, the separation of the visual system and protocerebrum anlagen in the anterior procephalon. In directly developing insects like grasshopper, seven expression domains are formed during this process. The activation of four of these, which correspond to polar expression pairs in the optic lobe anlagen and the protocerebral ectoderm, has shifted to postembryonic stages in flour beetle and Drosophila. The remaining three domains map to the protocerebral neuroectoderm, and form by disintegration of a large precursor domain in flour beetle and grasshopper. In Drosophila, the precursor domain remains intact, constituting the previously described “head blob”. These data document major changes in the expression of an early patterning gene correlated with the dramatic evolution of embryonic visual system development in the Holometabola.     

中国石蕊科地衣研究之四石蕊属地衣新种及中国新记录

摘要:本文报道了中国横断山地区石蕊属地衣12种,其中新种1个:贡嘎石蕊(Cladonia ngganensis S.Y. Guo & Wei),中国新记录11种:类黄粉石蕊(Cl. bacilliformis),比蒙氏石(Cl. beaumontii),小棍棒石蕊(Cl. clavulifera),圆筒石蕊(Cl. cylindrica),具粉石蕊(Cl. farinacea),北海道石蕊(Cl. hokkaidensis),厚叶石蕊(Cl. incrassata),大叶石蕊(Cl. macrophylla),丛杯石蕊( Cl. mateocyatha),多孔石蕊(Cl. multiformis)和亚石蕊(Cl. subrangiformis)。对于每一种的化学成分及地理分布进行了测定和分析。     

Molecular identification of Taenia spp. in wolves (Canis lupus), brown bears (Ursus arctos) and cervids from North Europe and Alaska

Taenia tapeworms of Finnish and Swedish wolves (Canis lupus) and Finnish brown bears (Ursus arctos), and muscle cysticerci of Svalbard reindeer (Rangifer tarandus platyrhynchus), Alaskan Grant's caribou (Rangifer tarandus granti) and Alaskan moose (Alces americanus) were identified on the basis of the nucleotide sequence of a 396 bp region of the mitochondrial cytochrome c oxidase subunit 1 gene. Two species were found from wolves: Taenia hydatigena and Taenia krabbei. The cysticerci of reindeer, caribou and one moose also represented T. krabbei. Most of the cysticercal specimens from Alaskan moose, however, belonged to an unknown T. krabbei-like species, which had been reported previously from Eurasian elks (Alces alces) from Finland. Strobilate stages from two bears belonged to this species as well. The present results suggest that this novel Taenia sp. has a Holarctic distribution and uses Alces spp. as intermediate and ursids as final hosts.     

A molecular phylogeny of Hebeloma species from Europe

In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.     

Fungal Thyroiditis: An Overview

The authors review the epidemiology, clinical manifestations, diagnosis, and treatment of fungal thyroiditis cases previously reported in the medical literature. Aspergillus was by far the most common cause of fungal thyroiditis. Immunocompromised patients, such as those with leukemia, lymphoma, autoimmune diseases, and organ-transplant patients on pharmacological immunosuppression were particularly at risk. Fungal thyroiditis was diagnosed at autopsy as part of disseminated infection in a substantial number of patients without clinical manifestations and laboratory evidence of thyroid dysfunction. Local signs and symptoms of infection were indistinguishable from other infectious thyroiditis and included fever, anterior cervical pain, thyroid enlargement sometimes associated with dysphagia and dysphonia, and clinical and laboratory features of transient hyperthyroidism due to the release of thyroid hormone from follicular cell damage, followed by residual hypothyroidism. Antemortem diagnosis of fungal thyroiditis was made by direct microscopy and culture of a fine-needle aspirate, or/and biopsy in most cases. Since most patients with fungal thyroiditis had disseminated fungal infection with delay in diagnosis and treatment, the overall mortality was high.