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Jones, GJ, Palenik BP, Morel FMM.  1987.  Trace-Metal Reduction by Phytoplankton - the Role of Plasmalemma Redox Enzymes. Journal of Phycology. 23:237-244.   10.1111/j.1529-8817.1987.tb04131.x   AbstractWebsite

The phytoplankton cell surface reduces external copper(II) and iron(III) complexes and redox dyes. This reductive activity appears to be mediated by one or more plasmalemma redox enzymes. Trace metal complexes are directly reduced by the redox enzyme, therefore the reduction rate is not regulated by the metal free ion activity in solution. This is in direct contrast to previous measurements of trace metal interactions with the phytoplankton cell membrane. Half-saturation constants for the reduction of Cu(II) complexes with carbonate, phenanthroline and bathocuproinedisulfonate are in the range 2.3–14.7 μM, which suggests that trace metal complexes are not the main electron acceptor in natural waters. In the diatom Thalassiosira weissflogii there is additional reductive activity associated with the cell wall.

Palenik, B, Zafiriou OC, Morel FMM.  1987.  Hydrogen-peroxide production by a marine phytoplankton. Limnology and Oceanography. 32:1365-1369. AbstractWebsite
Palenik, B, Morel FMM.  1988.  Dark production of hydrogen peroxide in the Sargasso Sea. Limnology and Oceanography. 33:1606-1611. AbstractWebsite
Morel, FMM, Palenik B.  1989.  The aquatic chemistry of biofilms. Structure and Function of Biofilms. 50( Characklis WG, Wilderer PA, Eds.).:351-366., Chichester: John Wiley & Sons, Ltd.   10.1002/jctb.280500315   Abstract
Palenik, B, Block JC, Burns RG, Characklis WG, Christensen BE, Ghiorse WC, Gristina AG, Morel FMM, Nichols WW, Tuovinen OH, Tuschewitzki GJ, Videla HA.  1989.  Biofilms: Properties and processes. Structure and Function of Biofilms. 50( Characklis WG, Wilderer PA, Eds.).:351-366., Chichester: John Wiley & Sons, Ltd.   10.1002/jctb.280500315   Abstract
Palenik, B, Kieber DJ, Morel FMM.  1989.  Dissolved organic nitrogen use by phytoplankton: The role of cell-surface enzymes. Biological Oceanography. 6:347-354. AbstractWebsite
Price, NM, Harrison GI, Hering JG, Hudson RJ, Nirel PMV, Palenik B, Morel FMM.  1989.  Preparation and chemistry of the artificial algal culture medium Aquil. Biological Oceanography. 6:443-461. AbstractWebsite
Palenik, B, Morel FMM.  1990.  Comparison of cell-surface L-amino-acid oxidases from several marine-phytoplankton. Marine Ecology-Progress Series. 59:195-201.   10.3354/meps059195   AbstractWebsite
Palenik, B, Morel FMM.  1990.  Amino acid utilization by a marine phytoplankton: A novel mechanism. Limnology and Oceanography. 35:260-269. AbstractWebsite
Roulier, MA, Palenik B, Morel FMM.  1990.  A method for the measurement of choline and hydrogen-peroxide in seawater. Marine Chemistry. 30:409-421.   10.1016/0304-4203(90)90084-p   AbstractWebsite

The horseradish peroxidase-mediated dimerization of hydroxyphenylpropionic acid can be used to measure hydrogen peroxide in seawater. The method was optimized and interferences investigated, and the method was then adapted to the measurement of choline in seawater. The enzyme choline oxidase is used specifically to oxidize choline to produce betaine and H2O2, and the latter is measured. Possible interferences with this method were investigated, and choline was measured in coastal seawater, where it varied from 0 to 45 nM.

Palenik, B, Price NM, Morel FMM.  1991.  Potential effects of UV-B on the chemical environment of marine organisms . Environmental Pollution. 70:117-130.   10.1016/0269-7491(91)90084-a   AbstractWebsite

An increase in ultraviolet-B (UV-B) due to depletion of stratospheric ozone may affect growth of marine phytoplankton by altering the chemistry of their environment. Production of bioactive free radicals, photodecomposition of organic matter, and availability of trace metals are likely to be altered by increased UV-B flux. Such changes to the chemical environment may be both deleterious and benefical to marine phytoplankton. Extracellular free radicals such as OH, Br2-, and CO3- are predicted to have a negligible impact, but superoxide and its decomposition product hydrogen peroxide may react rapidly with cell surfaces and destroy membrane function and integrity. Increased UV-B will enhance the bioavailability of the redox active trace metals Fe and Cu. Thus, in the Fe-limited high latitude ocean, increased Fe availability may promote phytoplankton production, while in other parts of the ocean increased Cu availability may be toxic. Overall, the interdependent direct and indirect effects of UV-B on phytoplanton may compensate for each other and account for the ability of marine ecosystems to be subjected to widely variable UV-B flux without apparent damage.

Palenik, B, Morel FMM.  1991.  Amine Oxidases of Marine-Phytoplankton. Applied and Environmental Microbiology. 57:2440-2443. AbstractWebsite

Some phytoplankton utilized a novel mechanism for obtaining nitrogen from primary amines. They oxidized the primary amines to produce extracellular hydrogen peroxide and aldehydes and used the third reaction product, ammonium, as a nitrogen source. The specificity, regulation, inhibition by bromoethylamine, and potential dependence on copper of this process are described.

Palenik, B.  1992.  Polymerase evolution and organism evolution. Current opinion in genetics & development. 2:931-6.   10.1016/s0959-437x(05)80118-2   AbstractWebsite

The continuing exploration of the structure-function relationships of polymerases and the use of polymerases as phylogenetic tools complement each other, as seen in the literature for the past year. DNA-dependent RNA-polymerase gene sequences, in particular, have been used both to define functional domains in the protein encoded and recently to explore fundamental questions in evolution.

Chisholm, SW, Frankel SL, Goericke R, Olson RJ, Palenik B, Waterbury JB, Westjohnsrud L, Zettler ER.  1992.  Prochlorococcus marinus nov. gen. nov. sp.: An oxyphototrophic marine prokaryote containing divinyl chlorophyll a and b . Archives of Microbiology. 157:297-300.   10.1007/bf00245165   AbstractWebsite

Several years ago, prochlorophyte picoplankton were discovered in the N. Atlantic. They have since been found to be abundant within the euphotic zone of the world's tropical and temperate oceans. The cells are extremely small, lack phycobiliproteins. and contain divinyl chlorophyll a and b as their primary photosynthetic pigments. Phylogenies constructed from DNA sequence data indicate that these cells are more closely related to a cluster of marine cyanobacteria than to their prochlorophyte 'relatives' Prochlorothrix and Prochloron. Several strains of this organism have recently been brought into culture, and herewith are given the name Prochlorococcus marinus.

Palenik, B, Haselkorn R.  1992.  Multiple evolutionary origins of prochlorophytes, the chlorophyll b-containing prokaryotes. Nature. 355:265-267.   10.1038/355265a0   AbstractWebsite

PROCHLOROPHYTES are prokaryotes that Carry out oxygenic photosynthesis using chlorophylls a and b, but lack phycobiliproteins as light-harvesting pigments 1. These characteristics distinguish them from cyanobacteria, which contain phycobiliproteins, but no chlorophyll b. Three prochlorophyte genera have been described: Prochloron 1-3, Prochlorothrix 4 and Prochlorococcus 5,6. The prochlorophytes share their pigment characteristics with green plant and euglenoid chloroplasts, which has led to a debate on whether these chloroplasts may have arisen from an endosymbiotic prochlorophyte rather than a cyanobacterium 2,7. Molecular sequence data, including those presented here based on a fragment of the rpoC1 gene encoding a subunit of DNA-dependent RNA polymerase, indicate that the known prochlorophyte lineages do not include the direct ancestor of chloroplasts 8-11. We also show that the prochlorophytes are a highly diverged polyphyletic group. Thus the use of chlorophyll b as a light-harvesting pigment has developed independently several times in evolution. Similar conclusions have been reached in parallel studies using 16S ribosomal RNA sequences 12.

Swift, H, Palenik B.  1993.  Prochlorophyte evolution and the origin of chloroplasts: Morphological and molecular evidence. Origins of plastids : symbiogenesis, prochlorophytes, and the origins of chloroplasts. ( Lewin RA, Ed.).:123-139., New York: Chapman & Hall Abstract
Pantoja, S, Lee C, Marecek JF, Palenik BP.  1993.  Synthesis and use of fluorescent molecular probes for measuring cell-surface enzymatic oxidation of amino-acids and amines in seawater. Analytical Biochemistry. 211:210-218.   10.1006/abio.1993.1259   AbstractWebsite

A method for investigating cell-surface enzymatic oxidative deamination of amino acids and amines in sea water was developed. This technique used synthetic fluorescent Lucifer Yellow derivatives of the amino acid lysine and the amine cadaverine as molecular probes to investigate oxidation pathways and rates. The probes were chemically stable under the conditions used and did not adsorb to container surfaces. The oxidative deamination of the fluorescent probes added to phyto-plankton cultures and the subsequent production of their fluorescent oxidation products could be selectively detected by HPLC at 250 pM levels. This approach allows selective investigation of cell-surface enzymatic oxidation since neither transport of the probes across the cell membrane nor chemical transformation of the probes occurs. Bacteria were also capable of oxidizing the fluorescent amino acid probe.

Palenik, B.  1994.  Cyanobacterial Community Structure as Seen from Rna-Polymerase Gene Sequence-Analysis. Applied and Environmental Microbiology. 60:3212-3219. AbstractWebsite

PCR was used to amplify DNA-dependent RNA polymerase gene sequences specifically from the cyanobacterial population in a seawater sample from the Sargasso Sea. Sequencing and analysis of the cloned fragments suggest that the population in the sample consisted of two distinct clusters of Prochlorococcus-like cyanobacteria and four clusters of Synechococcus-like cyanobacteria. The diversity within these clusters was significantly different, however. Clones within each Synechococcus-like cluster were 99 to 100% identical, while each Prochlorococcus-like cluster was only 91% identical at the nucleotide level. One Prochlorococcus-like cluster was significantly more closely related to a Mediterranean Sea (surface) Prochlorococcus isolate than to the other cluster, showing the highly divergent nature of this group even in one sample. The approach described here can be used as a general method for examining cyanobacterial diversity, while an oligotrophic ocean ecosystem such as the Sargasso Sea may be an ideal model for examining diversity in relation to environmental parameters.

Palenik, B, Koke JA.  1995.  Characterization of a nitrogen-regulated protein identified by cell-surface biotinylation of a marine-phytoplankton. Applied and Environmental Microbiology. 61:3311-3315. AbstractWebsite

The biotinylating reagent succinimidyl 6-(biotinamido)hexanoate was used to label the cell surfaces of the cosmopolitan, marine, eukaryotic microorganism Emiliania huxleyi under different growth conditions. Proteins characteristic of different nutrient conditions could be identified. In particular, a nitrogen-regulated protein, nrp1, has an 82-kDa subunit that is present under nitrogen limitation and during growth on urea, It is absent under phosphate limitation or during exponential growth on nitrate or ammonia. nrp1 is the major membrane or wall protein in nitrogen-limited cells and is found in several strains of E, huxleyi, It may be a useful biomarker for examining the physiological state of E. huxleyi cells in their environment.

Palenik, B, Swift H.  1996.  Cyanobacterial evolution and prochlorophyte diversity as seen in DNA-dependent RNA polymerase gene sequences. Journal of Phycology. 32:638-646.   Doi 10.1111/J.0022-3646.1996.00638.X   AbstractWebsite

Nucleotide sequence data from DNA-dependent RNA polymerase (rpoC) genes were used to examine the phylogenetic relationships among the phycobiliprotein- and three known chlorophyll b-containing (prochlorophyte) cyanobacteria. The phylogenetic trees obtained confirm the polyphyletic nature of the prochlorophytes. Data from Prochloron cells obtained form six different tunicate host species suggest that at least two closely related groups of Prochloron exist in the same area in Palau, West Caroline Islands. Overall, however, the genetic diversity within the analyzed samples was much smaller than within the nonsymbiotic Prochlorococcus.

Dyhrman, ST, Palenik BP.  1997.  The identification and purification of a cell-surface alkaline phosphatase from the dinoflagellate Prorocentrum minimum (Dinophyceae). Journal of Phycology. 33:602-612.   10.1111/j.0022-3646.1997.00602.x   AbstractWebsite

Two cell-surface proteins were identified in the dinoflagellate Prorocentrum minimum (Pavillard) Schiller strain CCMP 1329 that are evident in phosphate-limited cultures, but not in nitrate-limited cultures or cultures growing-exponentially in complete media. These proteins were detected by labeling cell-surface proteins with the biotinylating reagent succinimidyl 6-(biotinamido) hexanoate. One protein, of approximately 200,000 daltons was purified using differential centrifugation, detergent extraction, and gel filtration chromatography. This purified protein was able to hydrolyze orthophosphate groups from p-nitrophenylphosphate at pH 8, indicating it is an alkaline phosphatase, although it is larger than other alkaline phosphatases isolated to date from most microorganisms. This protein may be induced to help P. minimum cleave orthophosphate groups from organic forms of phosphate in marine environments. Ultimately, this protein could represent a unique antigen for developing an antibody probe for examining the relationships between phosphate stress and bloom formation in P. minimum, and perhaps other dinoflagellates, in the field.

Toledo, G, Palenik B.  1997.  Synechococcus diversity in the California Current as seen by RNA polymerase (rpoC1) gene sequences of isolated strains. Applied and Environmental Microbiology. 63:4298-4303. AbstractWebsite

Because they are ubiquitous in a range of aquatic environments and culture methods are relatively advanced, cyanobacteria may be useful models for understanding the extent of evolutionary adaptation of prokaryotes in general to environmental gradients. The roles of environmental variables such as light and nutrients in influencing cyanobacterial genetic diversity are still poorly characterized, however, In this study, a total of 15 Synechococcus strains were isolated from the oligotrophic edge of the California Current from two depths (5 and 95 m) with large differences in fight intensity, light quality, and nutrient concentrations. RNA polymerase gene (rpoC1) fragment sequences of the strains revealed two major genetic lineages, distinct from other marine or freshwater cyanobacterial isolates or groups seen in shotgun-cloned sequences from the oligotrophic Atlantic Ocean. The California Current low-phycourobilin (CCLPUB) group represented by six isolates in a single lineage was less diverse than the California Current high-phycourobilin (CCHPUB) group with nine isolates in three relatively divergent lineages. The former,vas found to be the closest known genetic group to Prochlorococcus spp., a chlorophyll b-containing cyanobacterial group, Having an isolate from this group will be valuable for looking at the molecular changes necessary for the transition from the use of phycobiliproteins to chlorophyll b as light-harvesting pigments. Both of the CCHPUB and CCLPUB groups included strains obtained from surface (5 m) and deep (95 m) samples, Thus, contrary to expectations, there was no clear correlation between sampling depth and isolation of genetic groups, despite the large environmental gradients present, To our knowledge, this is the first demonstration with isolates that genetically divergent Synechococcus groups coexist in the same seawater sample.

Palenik, B, Henson SE.  1997.  The use of amides and other organic nitrogen sources by the phytoplankton Emiliania huxleyi. Limnology and Oceanography. 42:1544-1551. AbstractWebsite

Although dissolved organic nitrogen (DON) is beginning to be seen as a potentially important nitrogen source for phytoplankton, much remains to be learned about its components and their utilization. Emiliania huxleyi, a cosmopolitan eukaryotic phytoplankton species abundant in oligotrophic oceans and during blooms in some coastal regions, was screened for use of various DON compounds. Hypoxanthine and other purines support the nickel-dependent growth of most E. huxleyi strains. Acetamide and formamide but not longer chain aliphatic amides were found to be excellent nitrogen sources for growth; other phytoplankton were also found to utilize acetamide but not formamide. In E. huxleyi, small amides are transported into the cell followed by degradation to ammonia, possibly by amide-specific enzymes. The related molecules hydroxyurea and thiourea were toxic to the cells and caused an increase in fluorescence consistent with blockage of photosystem II. This fluorescence increase was inhibited by urea and acetamide, suggesting transport of hydroxyurea, thiourea, urea, and acetamide by the same or closely related transporters.

Palenik, B, Wood MA.  1998.  Molecular markers of phytoplankton status and their application at the level of individual cells. Molecular Approaches To The Study Of The Ocean. ( Cooksey KL, Ed.).:187-205., New York: Chapman & Hall Abstract
Palenik, B, Dyhrman ST.  1998.  Recent progress in understanding the regulation of marine primary productivity by phosphorus. Phosphorus in Plant Biology: Regulating Roles in Molecular, Cellular, Organismic and Ecosystem Processe. ( Lynch JP, Deikman J, Eds.).:26-38., Rockville, MD: American Society of Plant Physiologists Abstract