固氮蓝藻Anabaena sp.7120的叶绿素蛋白复合体的分离和光谱特性的研究

用光合膜片增溶和SDS-聚丙烯酰胺凝胶电泳方法,从固氮蓝藻Anabaena sp.7120分离到7条色素带。迁移率较慢的五条叶绿素蛋白复合体带,具有相同的吸收光谱和室温荧光光谱特性。它们的红区最大吸收峰在676nm;蓝区最大吸收峰在438nm。它们的室温荧光发射最高峰在672—673nm;在710,732和740nm都有小峰。这些是CPⅠ叶绿素所特有的。我们认为这5条带都是属于光系统Ⅰ的叶绿素蛋白复合体。另一条迁移率稍快的叶绿素蛋白复合体带为CPⅡ。它的红区最大吸收峰在672nm;蓝区最大吸收峰在436n

有机磷农药在水生态系中生物净化机理研究---- ----4. Pseudomonas sp. CTP-01 的对硫磷水解酶诱导合成性质

Pseudomonas sp.CTP-01的对硫磷水解酶具有底物诱导合成性质。停滞生长期的细胞接触底物半小时即产生相应酶的合成,而指数生长期的细胞接触底物48小时后才发生酶的合成。甲基对硫磷及对硝基酚也具有诱导作用,可见合成对硫磷水解酶的诱导特异基团可能与对硝基酚及其苯环上的取代基有密切关系。

三带喙库蚊寄生等索线虫(Isomermis sp.)生活史的初步研究

本文首次报导了武汉市郊区三带喙库蚊(Culex tritaeniorhynchus)孑孓体内寄生等索线虫(Isomermis sp.)的生活史。等索线虫在6月至9月份对宿主的寄生率的幅度为5%～48%。等索线虫一年内可发生多代,当气温在26°～33℃时,完成一代生活史的周期为22～28天;并成功地进行了室内人工感染;此外就等索线虫对宿主的感染强度,寄生部位;雌雄性比等问题也进行了初步的研究。

蓝裸甲藻(新种)(Gymnodinium cyaneum Hu sp.nov.)藻胆素(Phycobilin)的发现及其意义

<正> 在藻类的光合色素系统中,叶绿素a是各门类所共有的.但就其采收光能的天线色素而言,因门类而有很大的差别.因此,天线色素的不同就成为研究藻类系统分类和演化问题的重要依据之一.藻胆素是某些藻类光合系统中的主要天线色素.研究表明,藻胆素仅存在于蓝藻类(cyanophyceae)、红藻类(Rhodophyceae)和隐藻类(cryptophyceae)中.甲藻(Pyrrophyceae)的某些类型因其细胞核缺乏真核生物所具有的碱性蛋白而被称为间核生物(Mcsokaryota).从细胞核的性质来说,这些类型无

KHAWIA SAUROGOBII N. SP (CESTODA: CARYOPHYLLIDEA) FROM FRESHWATER FISH SAUROGOBIO SPP. (CYPRINIDAE) IN CHINA

Khawia saurogobii n. sp. is described from the intestine of the cyprinid fishes Saurogobio dabryi and Saurogobio dumerili in China. The new species belongs to the Lytocestidae and is placed in Khawia because of its afossate scolex, vitelline follicles in the cortical parenchyma, uterus not looping anterior to the cirrus sac, gonopores separate but close together in distinct genital atrium, external seminal vesicle absent, and postovarian follicles present. The new species differs from other congeneric species by the shape of the body markedly tapering posteriorly from the end of the anterior third, the shape of the scolex that is very short and markedly wider than the neck, spatulate without incisions, but shallow superficial grooves, vitelline follicles and testes starting immediately posterior to the scolex, and an ovary with long, posterior arms bent medially, thus giving the shape of an inverted A.

Fridericia liangi sp nov (Enchytraeidae, Oligochaeta) from Changbaishan Mountain, China

We describe one new enchytraeid species, Fridericia liangi sp. nov., from Mt. Changbaishan, Jilin Province, northeastern China. It was collected from soils at the foot of Changbaishan Mountain and is distinguished from all known congeners by the following combination of characters: 1) no lateral chaetae, only ventral chaetae throughout, 2) a maximum of four chaetae in ventral preclitellar bundles, 3) one chaeta in ventral postclitellar bundles, 4) dorsal pores from VII on, 5) esophageal appendages unbranched, 6) coelomocytes without refractile vesicles, 7) clitellum girdle shaped, well developed, 8) no subneural glands, and 9) spermathecae simple.

DnaJ-like protein gene sll1384 is involved in phototaxis in Synechocystis sp PCC 6803

In Synechocystis sp. PCC 6803, gene sll1384 encodes a protein with a DnaJ domain at its N-terminal portion and a TPR domain at the C-terminal portion. An sll1384 mutant shows no difference from the wild type in adaptation to different temperatures, but almost completely loses its capability of phototactic movement. After complementation with sll1384, the mutant regains the phototaxis. As shown with electron microscopy, on the cell surface, mutant cells have pili that appear to be the same as that of the wild type. Also, the transformation efficiency remains unchanged in the mutant. It is postulated that Sll1384 regulates phototaxis of Synechocystis through protein-protein interaction. It is the first DnaJ-like protein gene identified in a cyanobacterium for a role in phototaxis.

Outer membrane proteins induced by iron deficiency in Anabaena sp PCC 7120

Iron deficiency can induce cyanobacteria to synthesize siderophore receptor proteins on the outer membrane to enhance the uptake of iron. In this study, an outer membrane of high purity was prepared from Anabaena sp. PCC 7120 based on aqueous polymer two-phase partitioning and discontinuous sucrose density ultra-centrifugation, and the induction of outer membrane proteins by iron deficiency was investigated using 2-D gel electrophoresis. At least. five outer membrane proteins were newly synthesized or significantly up-regulated in cells transferred to iron-deficient conditions, which were all identified to be siderophore receptor proteins according to MALDI-TOF-MS analyses. Bacterial luciferase reporter genes luxAB were employed to monitor the transcription of the encoding genes. The genes were induced by iron deficiency at the transcriptional level in different responsive modes. Luciferase activity expressed from an iron-regulated promoter may be used as a bioreporter for utilizable iron in natural water samples. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.

ApcD is necessary for efficient energy transfer from phycobilisomes to photosystem I and helps to prevent photoinhibition in the cyanobacterium Synechococcus sp PCC 7002

Phyrobilisomes (PBS) are the major light-harvesting, protein-pigment complexes in cyanobacteria and red algae. PBS absorb and transfer light energy to photosystem (PS) II as well as PS I, and the distribution of light energy from PBS to the two photosystems is regulated by light conditions through a mechanism known as state transitions. In this study the quantum efficiency of excitation energy transfer from PBS to PS I in the cyanobacterium Synechococcus sp. PCC 7002 was determined, and the results showed that energy transfer from PBS to PS I is extremely efficient. The results further demonstrated that energy transfer from PBS to PS I occurred directly and that efficient energy transfer was dependent upon the allophycocyanin-B alpha subunit, ApcD. In the absence of ApcD, cells were unable to perform state transitions and were trapped in state 1. Action spectra showed that light energy transfer from PBS to PS I was severely impaired in the absence of ApcD. An apcD mutant grew more slowly than the wild type in light preferentially absorbed by phyrobiliproteins and was more sensitive to high light intensity. On the other hand, a mutant lacking ApcF, which is required for efficient energy transfer from PBS to PS II, showed greater resistance to high light treatment. Therefore, state transitions in cyanobacteria have two roles: (1) they regulate light energy distribution between the two photosystems; and (2) they help to protect cells from the effects of light energy excess at high light intensities. (C) 2009 Elsevier B.V. All rights reserved.

Morphological and molecular phylogenetic analysis of two Saprolegnia sp (Oomycetes) isolated from silver crucian carp and zebra fish

Two Saprolegnia isolates, JY isolated from silver crucian carp (Carassius auratus gibelio Bloch) and BMY isolated from zebra fish (Brachydanio rerio Hamilton) came from infections occurring concurrently in different locations in China. To confirm whether the two isolates were from the same Saprolegnia clone, comparative studies have been carried out based on their morphological, physiological and molecular characteristics. Observations showed that morphologically (both asexual and sexual organs) the two isolates were broadly similar and both isolates under-went repeated zoospore emergence. Comparing 704 base pairs of internal transcribed spacer (ITS) region and the 5.8S rDNA, we found isolates JY and BMY shared an identical ITS sequence with a minor variation (99.6 % similarity). Forty available sequences for representatives Saprolegnia spp. belonged to four phylogenetically separate clades. The two studied isolates fell within clade I that comprised a group of isolates which showed almost an identical ITS sequence but had been identified as a number of different morphological species. our findings suggest that isolates JY and BMY appear to belong to the S. ferax clade and this clade (1) contains a number of closely related phylogenetic species. This is distinct from the more common fish pathogenic isolates, which belong to the S. parasitica clade (III) and are characterized by having cysts decorated by bundles of long hooked hairs and two further clades (II and IV) containing largely saprotrophic or soil born species. (C) 2009 Published by Elsevier Ltd on behalf of The British Mycological Society.

The first study on the effects of microcystin-RR on gene expression profiles of antioxidant enzymes and heat shock protein-70 in Synechocystis sp PCC6803

Microcystins are heptapeptide toxins produced by cyanobacteria. Microcystin-RR(MC-RR) is a common variant among the 80 variants identified so far. There have been many investigations documenting the toxic effects of microcystins on animals and higher plants, but little is known on the toxic effects of microcystins on algae, especially at molecular level. We studied the effects of MC-RR on gene expression profile of a few antioxidant enzymes and heat shock protein-70 (Hsp70) in Synechocystis sp. PCC6803. After two days post-exposure, a high dose toxin (5 mg/l, about 4.8 x 10(-3) mM) significantly increased expression levels of the genes gpx1, sodB, katG, acnB, gamma-TMTand dnaK2, while a relatively low dose toxin (1 mg/l, about 9.63 x 10(-4) mM) induced a moderate and slow increase of gene expression. Our results indicate that MC-RR could induce the oxidative stress in Synechocystis sp. PCC6803 and the increase in gene expression of antioxidant enzymes and Hsp70 might protect the organism from the oxidative damage. in addition, cell aggregation was observed during the early period of exposure, which might be a specific oxidative stress reaction to MC-RR. (C) 2008 Elsevier Ltd. All rights reserved.

Depletion of Vipp1 in Synechocystis sp PCC 6803 affects photosynthetic activity before the loss of thylakoid membranes

A vipp1 mutant of Synechocystis sp. PCC 6803 could not be completely segregated under either mixotrophic or heterotrophic conditions. A vipp1 gene with a copper-regulated promoter (P-petE-vipp1) was integrated into a neutral platform in the genome of the merodiploid mutant. The copper-induced expression of P-petE-vipp1 allowed a complete segregation of the vipp1 mutant and observation of the phenotype of Synechocystis 6803 with different levels of vesicle-inducing protein in plastids 1 (Vipp1). When P-petE-vipp1 was turned off by copper deprivation, Synechocystis lost Vipp1 and photosynthetic activity almost simultaneously, and at a later stage, thylakoid membranes and cell viability. The photosystem II (PSII)-mediated electron transfer was much more rapidly reduced than the PSI-mediated electron transfer. By testing a series of concentrations, we found that P-petE-vipp1 cells grown in medium with 0.025 mu M Cu2+ showed no reduction of thylakoid membranes, but greatly reduced photosynthetic activity and viability. These results suggested that in contrast to a previous report, the loss of photosynthetic activity may not have been due to the loss of thylakoid membranes, but may have been caused more directly by the loss of Vipp1 in Synechocystis 6803.

Microcystin-RR induces physiological stress and cell death in the cyanobacterium Aphanizomenon sp DC01 isolated from Lake Dianchi, China

The phytoplankton community in Lake Dianchi (Yunnan Province, Southwestern China) is dominated in April by a bloom of Aphanizomenon, that disappears Suddenly and is displaced by a Microcystis bloom in May. The reasons for the rapid bloom disappearance phenomenon and the temporal variability in the composition of phytoplankton assemblages are poorly understood. Cell growth, ultrastructure and physiological changes were examined in cultures of Aphanizomenon sp. DC01 isolated from Lake Dianchi exposed to different closes of rnicrocystin-RR (MC-RR) produced by the Microcystis bloom. MC-RR concentrations above 100 mu g L-1 markedly inhibited the pigment (chlorophyll-a, phycocyanin) synthesis and caused an increase of soluble carbohydrate and protein contents and nitrate reductase activity of toxin-treated blue-green algae. A drastic. reduction in photochemical efficiency of PSII (Fv/Fm) was also found. Morphological examinationn showed that the Aphanizomenon filaments disintegrated and file cells lysed gradually after 48 h Of toxin exposure. Transmission electron microscopy revealed that cellular inclusions of stressed cells almost leaked out completely and the cell membranes were grossly damaged. These findings demonstrate the allelopathic activity of Microcystis aeruginosa inducing physiological stress and cell death of Aphanizomenon sp. DC01 Although the active concentrations of microcystin were rather high, we propose that microcystin may function as allelopathic Substance due to inhomogeneous toxin concentrations close to Microcystis cells. Hence, it may play a role in species Succession of Aphanizomenon and Microcystis in Lake Dianchi.

Peridiniopsis niei sp nov (Dinophyceae), a new species of freshwater red tide dinoflagellates from China

A new freshwater phototrophic species of the dinoflagellate genus Peridiniopsis, P. niei sp. nov., is described based on morphology. The new species appeared during spring with densities up to 1.48 x 10(7) cells L-1 in some tributaries and gullies of Three Gorge Reservoir and Lake Donghu, China, forming red tides. Peridiniopsis niei is a cyst-producing freshwater dinoflagellate that belongs to the group Penardii. The plate tabulation is po+x+4 '+0a+6 ''+5c+5s+5 '''+2 '''' and the plate pattern is symmetric. The cells of P. niei are pentagonal in ventral view, the epitheca is larger than the hypotheca, making up about 2/3 the length of the cell. Plate 3 ' is hexangular. The closest species to P. niei is P. penardii (Lemmermann) Bourrelly, but cells of the former are pentagonal, very compressed dorsoventrally, and the hypotheca is truncated with one transparent, robust spine on each antapical plate.

Fridericia dianchiensis sp nov (Enchytraeidae, oligochaeta) from Yunnan Province, China

Fridericia dianchiensis, a new enchytraeid species collected from Yunnan Province, is described here. It is characterized by a combination of the following characters: 1) lateral bundles containing maximum 3 chaetae; 2) esophageal appendages with 3-4 simple, terminal branches; 3) dorsal vessel originating in XX-XXIII; 4) sub-neural glands absent; 5) seminal vesicle large, occupying two segments; 6)clitellum girdle-shaped or gland cells absent between bursal slits and pre-middle ventrally; 7) coelomocytes without refractile vesicles, 8) spermatheca without diverticula and both ampullae broadly united; and 9) long spermathecal ectal duct without gland at the orifice.