Alterations in the Heat Response of Chlorella ellipsoidea by Deuteration

For the elucidation of the isotope effect on cell functionsof deuterium (D) incorporated into cell constituents, alterationsin the heat response of D-exchanged Chlorella ellipsoidea (D-Chlorella)were investigated. D-Chlorella cells obtained by culture inmedium that contained 60 mol% D₂O were assayed for their responseto heat in H₂O medium to rule out the solvent isotope effectof D₂O. Upon heating at 41–45?C, the heat sensitivityof D-Chlorella was greater than that of ordinary (H-Chlorella)cells; at 43?C, the heat sensitivity of D-Chlorella was 1.5–1.6times higher than that of H-Chlorella. For the induction ofresistance to heating, preheating of the cells at a lower temperaturethan that used for heat treatment was effective in the caseof both D- and H-Chlorella. However, the optimum temperaturefor preheating of D-Chlorella (34?C) was lower than for H-Chlorella(36–37?C). With preheating at 34?C, heat-shock proteins(HSPs), in particular proteins of 62 and 79 kDa, were inducedsimilarly in both types of cell. However, the gel-electrophoreticpatterns of HSPs induced at 37?C were differed somewhat betweenD- and H-Chlorella. These results suggest that the responseof cells to heat, in particular the induction of resistanceto heating and the synthesis of HSPs, was altered by deuterationof cell constituents. (Received June 11, 1990; Accepted November 24, 1990)     

Evidence from Crosslinking for Nearest-Neighbor Relationships among the Three Extrinsic Proteins of Spinach Photosystem II Complexes that are Associated with Oxygen Evolution

Treatment of oxygen-evolving Photosystem II complexes, whichlack light-harvesting chlorophyll a/b proteins, with a seriesof disuccinimidyl esters with different chain lengths yieldeda crosslinked product which consisted of one molecule each ofthe extrinsic 33 kDa and 23 kDa proteins. In addition, crosslinkingbetween the 33 kDa protein and the chlorophyll-carrying 47 kDaprotein and between the 23 kDa and 17 kDa proteins was confirmed.Thus, the three extrinsic proteins are closely associated witheach other to form a complex which is attached to the PS IIreaction center complexes. (Received December 1, 1989; Accepted May 2, 1990)     

Developmental Analysis of Steady-State Levels of Cu/Zn and Mn Superoxide Dismutase mRNAs in Maize Tissues

The superoxide dismutase (Sod) steady-state mRNA levels in maizeseedlings and developing kernels were examined by RNA blot analysis,using Cu/Zn and Mn cDNA probes encoding the cytosolic and mitochondrialSOD isozymes, respectively. The cytosolic (Cu/Zn) Sod steady-statemRNA levels remained relatively constant for the various tissuesexamined. In contrast, the mRNA levels of the mitochondrial(Mn) SOD-3 isozyme increased in postgerminative scutella. Thesteady-state mRNA of the Atp2 gene, F₁ ATPase ß subunit,was compared to the Sod3 (Mn) mRNA levels. Results of this comparativestudy suggest that the steady-state levels of mRNAs transcribedby nuclear genes encoding essential mitochondrial proteins areindependently regulated throughout development. (Received April 2, 1990; Accepted September 10, 1990)     

Isolation of Chloroplasts from Poteriochromonas malhamensis with the Capacity for Translation

An improved method for the isolation of chloroplasts from Poteriochromonasmalhamensis is described. Poteriochromonas cells were brokenby passage through a nylon mesh with pores of 6µ in diameterat a flow rate of about 5 ml/15 s. After centrifugation thecrude chloroplast fraction was purified by centrifugation ina step gradient of Percoll. The isolated chloroplasts were enclosedby envelope membranes and were still surrounded in part by cytoplasmicresidues. The chloroplasts had the capacity for translation,which was both chloramphenicol-sensitive and cycloheximide-insensitive.The properties of these isolated chloroplasts from Poteriochromonasare discussed in relation to experiments on the transport intothe chloroplasts of nucleus-encoded proteins. ² Present address: Bundesgesundheitsamt, Zulassungsstelle furGentechnologie, Columbiadamm 3, D-1000 Berlin, F.R.G. (Received July 24, 1990; Accepted March 15, 1991)     

The 33 kDa Protein of the Oxygen-Evolving Complex: a Multi-Gene Family in Tomato

A cDNA was isolated by chance from tomato which had a high similarityto a cDNA clone from potato known to code for the 33 kDa proteinof the oxygen-evolving complex [van Spanje et al. (1991) PlantMol. Biol. 17: 157]. The sequence of a previously describedpartial cDNA clone from tomato [Ko et al. (1990) Plant Mol.Biol. 14: 217] which has also a high similarity but is not identicalto the sequence described here indicates that tomato containsat least two genes coding for 33 kDa proteins per haploid genome.This conclusion is supported by Southern blot analysis. Thetissue specific expression of the corresponding genes is described. (Received September 28, 1992; Accepted February 15, 1993)     

Touch-Inducible Genes for Calmodulin and a Calmodulin-Related Protein Are Located in Tandem on a Chromosome of Arabidopsis thaliana

Genes for calmodulin and calmodulin-related proteins in Arabidopsisare up-regulated by a variety of physical stimuli, which includerain, wind and touch [Braam and Davis (1990) Cell 60: 357].We have isolated five genes for calmodulin (AtCALl, 2, 3, 5,6) and one gene for a calmodulin-related protein (AtCAL4) froman Arabidopsis genomic library. Touch stimulus of Arabidopsisplants induces the accumulation of mRNA transcribed from AtCAL4andAtCAL5, but not from the other isolated genes. The two touch-induciblegenes are arrayed in tandem with a short intergenic region of700 bp but they show different organ-specific patterns of expression. (Received April 27, 1995; Accepted July 20, 1995)     

Cloning and Characterization of the nrtA Gene That Encodes a 45-kDa Protein Involved in Nitrate Transport in the Cyanobacterium Synechococcus PCC 7942

A 45-kDa protein in the cytoplasmic membrane of the cyanobacteriumSynechococcus PCC 7942 is involved in the active transport ofnitrate [Omata et al. (1989) Proc. Natl. Acad. Sci. USA 86:6612]. The gene coding for this protein (designated herein asnrtA) has been cloned and sequenced. The nrtA gene encodes aprotein of 443 amino acids with a calculated molecular weightof 48424. The deduced amino acid sequence of the protein is46.5% homologous to that of a 42-kDa cytoplasmic membrane proteinthat is synthesized under carbon-limited conditions in SynechococcusPCC 7942. (Received July 16, 1990; Accepted December 5, 1990)     

Stimulation of the Uptake of Sorbitol into Vacuoles from Apple Fruit Flesh by Abscisic Add and into Protoplasts by Indoleacetic Acid

The uptake of sorbitol into vacuoles from immature flesh ofapple fruit (Maluspumila Mill, var domestica Schneid.) was facilitatedby 10^–6 M ABA, while such uptake into protoplasts wasnot stimulated. By contrast, the application of 10^–5 MIAA facilitated uptake of sorbitol into protoplasts but didnot significantly into vacuoles. (Received July 17, 1990; Accepted December 25, 1990)     

Interaction between L-Pipecolic Acid and Water Extracts of Various Plant Species in Floral Induction of Lemna paucicostata

The flower-inducing activity of L-pipecolic acid was synergisticallyenhanced by simultaneous application of the water extracts ofLemna paucicostata and Pharbitis nil, but suppressed by thewater extracts of all other plants we examined. Simultaneousapplication of the water extract of Lemna enhanced the flower-inducingactivity of all plant water extracts. (Received June 6, 1990; Accepted July 7, 1990)     

Immunological Cross-Reactivity among Corresponding Proteins of Photosystems I and II from Widely Divergent Photosynthetic Organisms

Immunological cross-reactivity among corresponding proteinsassociated with photosystems I and II in higher plants, greenalgae, red algae and cyanobacteria were examined with antiseraraised against the proteins from Synechococcus elongatus andspinach. (1) Generally, the cross-reactivity was very high betweenclosely related species but decreased with increasing phylogeneticdistances between organisms. Exceptionally, proteins from redalgae showed lower reactivities with the antisera against thecyanobacterial proteins than did corresponding proteins fromgreen algae and higher plants. (2) The extent of the cross-reactivitywas found to vary with the antisera used. Three antisera preparedagainst large chlorophyll-carrying proteins of photosystem Iand photosystem II reaction center complexes of Synechococcusreacted with the corresponding proteins of all the organismsexamined. By contrast, an antiserum raised against the extrinsic35 kDa protein of the cyanobacterium reacted with none of corresponding33 kDa proteins of other species. The antiserum against thespinach 33 kDa protein showed a wider range of cross-reactivity.Antisera raised against the Dl and D2 proteins from spinachwere highly reactive with corresponding proteins from otherphotosynthetic organisms, whereas an antiserum against a well-conservedsequence of the spinach D2 protein showed limited cross-reactivity.The results show that, although the extent of immunologicalcross-reactivity is determined mainly by the homology betweenproteins, caution is indicated in the application of immunologicalmethods to determinations of the distribution of various proteinsrelated to photosystems I and II in very different organisms. (Received December 8, 1989; Accepted March 12, 1990)     

Functional Structure of the Oxygen-Evolving Unit of Photosystem II as Determined by Radiation Inactivation

The size of the complex that is essential for the electron-transferactivity from the oxygen-evolving center to the secondary electronacceptor, Q_B, is about 250 kDa, as determined by target-sizeanalysis after the radiation inactivation of functions of photosystemII (PS II). Inter-Chl tranfer of excitation energy was insensitiveto the radiation inactivation indicating that the masses ofCP47, CP43, and light-harvesting Chi a/b proteins are not includedin the functional size of the oxygen-evolving PS II complex.The transfer of electrons from the secondary electron donor,Z, to Q_B was catalyzed by a unit of only 65 kDa. The sizes ofthe complexes involved in these light-induced functions of PSII were dependent on the intensity of actinic light. Under saturatingintensities of light, the functional size of the complex fortransfer of electrons from Z to Q_B was 38 kDa, with a correspondingdecrease in the size of the oxygen-evolving PS II from 250 kDato 125 kDa [Takahashi, Mano and Asada (1985) Plant Cell Physiol.26: 383]. The protein of about 30 kDa functions in the photoreductionof the pheophytin molecule, as well as in the electron transferfrom Z to Q_A. Under low-intensity light, complexes having thesame sizes as those of the basal functional complexes undersaturating-intensity light are further required, probably tostabilize separated charges in the PS II reaction center andthe oxygen-evolving center. (Received June 20, 1990; Accepted September 18, 1990)     

Regulation of bacterioplankton production and biomass in an oligotrophic cleanvater lake--the importance of the phytoplankton community

Estimations of bacterioplankton production and biomass werecarried out in enclosure experiments during two consecutiveyears (1989 and 1990) in oligotrophic clearwater Lake Njupfatet.The lake was limed in November 1989, and the experiments werecarried out both in 1989 (unlimed) and in 1990 (limed). Bags(3001) were manipulated with inorganic phosphorus and nitrogen,organic carbon, and metazoan zooplankton abundance. Both years,bacterial production was stimulated by inorganic nutrients aloneand in combination with organic carbon. However, the increasein bacterial production when inorganic nutrients were addedalone was much stronger in 1990 than in 1989. In 1989. bacterialproduction increased strongly only when inorganic nutrientsand organic carbon were added together. The phytoplankton communitywas dominated by the cyanobacterium Merismopedia tenuis-simaduring 1989, and the phytoplankton biomass increased only slightlywhen receiving inorganic nutrients. In 1990, when the lake hadbeen limed. M.tenuissima had completely disappeared and thephytoplankton community, dominated by Chrysophyceae and Chlorophyceae,responded strongly to additions of inorganic nutrients. Theincreased phytoplankton productivity in 1990 may have resultedin increased release of organic carbon, and this in turn thatthe carbon limitation of bacterioplankton production decreasedfrom 1989 to 1990. Zooplankton had a positive effect on bacterioplanktonproduction in 1989, but no effect in 1990. The loss of bacterialbiomass approximated 60% of the bacterial production in 1989,while in 1990 it almost equalled the bacterioplankton production.     

Proteins Associated with Specific Host-Pathogen Relationships in Infections with Wheat Rust

The specific relationship between host and pathogen was studiedusing a criss-cross genetic system of well characterized, nearisogenic mutants of Triticum aestivum that differed in theircompatibility reaction to two genetically related mutant clonesof Puccinia recondita tritici. Specific and non-specific pathogenesis-relatedchanges in proteins were followed by pulse-labelling with [³⁵S]methionineof rust-inoculated and mock-inoculated wheat leaves, combinedwith SDS-PAGE and subsequent fluorography. Detectable changesin the patterns of the polypeptides synthesized "de novo" werenoted as early as 3 days after infection. Synthesis of a 39-kDapolypeptide was enhanced in incompatible reactions while synthesisof an 85-kDa and a 15-kDa polypeptide were enhanced in compatiblereactions. Synthesis of polypeptides present in the mock-inoculatedleaves was suppressed in both the compatible (52-kDa band) andincompatible interaction systems (37-kDa band). Comparisonswith a third mutant clone of rust, which elicits an inversecriss-cross relationship with the same wheat lines, indicatedthat most of the detected changes are likely to be associatedwith gene-for-gene relationships. (Received January 16, 1990; Accepted October 1, 1990)     

Armoured dinoflagellates in the NE Atlantic during the BOFS cruises, 1988-90

The armoured dinoulagellates present in 90 plankton samplescollected by the use of an Apatein closing net were enumerated.The samples were collected from various stations around the20W meridian and between 44 and 60N during the 1988, 1989and 1990 Biogeochemical Ocean Flux Study (BOFS) cruises. Atmost stations, samples were obtained from various depths, althoughin 1990 only the surface zone was sampled. A total of 126 specieswere identified, of which 49 have chloroplasts and are thoughtto be autotrophic, 47 are assumed to be heterotrophic and thenutritional type of the remainder is unknown. The samples collectedduring July 1988 were dominated by large numbers of the twophotosynthetic species Gonyaulax polygramma and Protoceratiunreticulatum (=Gonyaulax grindleyi). The much more intensivesampling of 1989 revealed several Ceratiun species, C.fusus,C.furca and C.lineazum, together with Gonyaulax polygramma,as the most common dinoflagellates. In 1990 the samples, whichwere taken during a Lagrangian survey in May-June, were alsodominated by Ceratium species. This time C.azoricwn was a majorcomponent and Protoceratium reticulatum was again present inhigh numbers as in 1988. A number of analyses were carried outon the data collected. It was found that the majority of themore frequent species were autotrophs and most were membersof the genus Ceraziwn. The effects of depth were shown to resultin reduced numbers of cells and species, but no clear associationwas found between species and depth. After the application ofDetrended Correspondence Analysis (DECORANA) to all surfacesamples, there was found to be a clear association between thespecies composition and both time of year and latitude. Watercolumn stability is also probably an important factor in speciescomposition and cell numbers. Seasonal changes in the frequencyof the main species were also noted with some, such as C.lineatum,being more important early in the summer and others, such asProtoceratium reticulatum and particularly G.polygramma, becomingdominant later. The use of Two-way Indicator Analysis (TWINSPAN)revealed some potential species associations.     

中国隧蜂属研究及新种新亚种记述(膜翅目：隧蜂科)

中国隧蜂属Halictuss．sir．的研究是根据Pesenko的分类系统撰写的[1,2]。有关中国隧蜂属的第1篇报道是Morawitz[3]记述由俄罗斯N．M．Przewalsky1877年采自天山的Halictusquadricinctus及H.resurgens（名为H．sexcinctussensuMorawitz）,1890年Morawitz又增加两种[4],即H.tetrazonicus（部分应为H．tsintouensis）及H.rubicundus,该两种是G.N．Potanin于1886年采自甘肃（标签上误写为蒙古“Mongolei”,详见Pesenko中国及蒙古隧蜂属的讨论[5]）。Strand也记述了中国的种类[6,7],其1909年的文章中记述了中国西部（“Jarkand”…     

Methyl Viologen-Dependent Cyclic Electron Transport in Spinach Chloroplasts in the Absence of Oxygen

The methyl viologen (MV)-dependent, linear electron flow fromPS II to PS I was severely blocked in intact or broken, uncoupledchloroplasts when oxygen was removed from the suspension medium,as revealed by measurements of chlorophyll fluorescence andthe rate of photoreduction of MV. Kinetics of the reductionof pre-oxidized P700 by a saturating light pulse showed thatreduced MV in the absence of oxygen re-reduces P700⁺ via theintersystem electron transport chain. Since the re-reductionof P700⁺ was inhibited by 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone,the MV-mediated cyclic electron flow, in contrast to the phenazinemethosulphate-catalyzed one, involves the plastoquinone pool.However, 2-n-heptyl-4-hydro-xyquinoline-N-oxide, 2-n-nonyl-4-hydroxyquinoline-N-oxideand antimycin A did not inhibit the MV-mediated flow. Thus,the inhibition of the linear electron flow in chloroplasts underanaerobic conditions suggested the overreduction of the plastoquinonepool as a result of the MV-mediated cyclic flow (Received February 13, 1990; Accepted March 31, 1990)     

Long-term dynamics of main mesozooplankton species in the central Baltic Sea

Long-term dynamics (1959–1997) of the copepod speciesPseudocalanus elongatus, Temora longicornis, Acartia spp. andCentropages hamatus, as well as the taxonomic group of cladocerans,are described for the open sea areas of the central Baltic Sea.Differences between areas, i.e. Bornholm Basin, Gdansk Deepand Gotland Basin, as well as between 5 year periods, were investigatedby means of Analysis of Variance (ANOVA). No significant differencesin mesozooplankton biomass between areas were found. On theother hand, clear time-trends could be demonstrated and relatedto salinity and temperature, with P.elongatus biomass mainlydependent on salinity and T.longicornis, Acartia spp. and cladoceransbiomasses dependent, to a large extent, on thermal conditions.Decreasing salinities since the early 1980s due to a lack ofmajor inflows of highly saline water from the North Sea andincreased river run-off, both triggered by meteorological conditions,obviously caused a decrease in biomass of P.elongatus. Contrarily,the standing stocks of the other abundant copepod species andcladocerans followed, to a large degree, the temperature developmentand showed, in general, an increase. The shift in species compositionduring this period is considered to be a reason for decreasinggrowth rates of Baltic herring (Clupea harengus) since the early1980s, and for sprat (Sprattus sprattus) since the early 1990s.Generally, it is suggested that low mesozooplankton biomassesin the 1990s were caused, at least partially, by amplified predationby clupeid fish stocks.     

Evidence from Crosslinking for a Close Association of the Extrinsic 33 kDa Protein with the 9.4 kDa Subunit of Cytochrome b 559 and the 4.8 kDa Product of the psb I Gene in Oxygen-Evolving Photosystem II Complexes from Spinach

Oxygen-evolving photosystem II complexes from spinach, whichlack light-harvesting chlorophyll a/b proteins, were treatedwith a bifunctional crosslinking reagent, hexamethylene-diisocyanate.Identification of crosslinked proteins with antisera raisedagainst various constituent proteins of the oxygen-evolvingPS II complex showed that the extrinsic 33 kDa protein is locatedless than 11 Å from the 9.4 kDa subunit of cytochromeb 559 and the 4.8 kDa product of psb I gene. (Received October 14, 1991; Accepted February 6, 1992)