Major Photosynthetic Pigments Research Articles

Spatial-Temporal Regularities of Hydrooptical Characteristics of the Ob River

Field studies conducted in spring (March 26 — April 9, 2022) and summer (June 5-16, 2022) in the Ob River mouth region at the three hydromorphological stations „Kazym-Mys“, „Azovy“, and „Salemal“ (YaNAO) to obtain new data on the hydrooptical characteristics of water in the Lower Ob river. Also, the trophic status and ecological state of the Lower Ob river region were assessed. The greatly varying light attenuation coefficient ε(λ) was calculated at the four characteristic wavelengths of 430, 450, 550, and 670 nm, respectively. It ranges from 9.3 m-1 to 22.1 m-1 during the winter low water (freeze-up) period and from 7.3 m-1 to 33.0 m-1 during the open water (high water) period. The calculated relative spectral contributions of major optically active components of water (pure water, suspension, yellow substance, chlorophyll) to ε(λ) suggest that suspension and yellow substance make up the maximal contribution at different horizons. Additionally, the calculated coefficient of light absorption by yellow substance кys(λ) varies within the ranges from 5.5 m-1 to 9.9 m-1 (spring) and from 3.1 m-1 to 17.0 m-1 (summer), respectively. The relative transparency was measured using the Secchi disc. The concentrations of yellow substance and major photosynthetic pigments — chlorophylls a, b, c, and carotenoids — were estimated alongside. The obtained results could be useful for environmental monitoring and predicting the dynamics of aquatic ecosystems in the region under climate change and increased anthropogenic pressure caused by the use of natural resources.

Ectothiorhodospira lacustris sp. nov., a New Purple Sulfur Bacterium from Low-Mineralized Soda Lakes That Contains a Unique Pathway for Nitric Oxide Reduction

Several strains of a Gram-negative, anaerobic photoautotrophic, motile, rod-shaped bacterium, designated as B14B, A-7R, and A-7Y were isolated from biofilms of low-mineralized soda lakes in central Mongolia and Russia (southeast Siberia). They had lamellar stacks as photosynthetic structures and bacteriochlorophyll a as the major photosynthetic pigment. The strains were found to grow at 25–35 °C, pH 7.5–10.2 (optimum, pH 9.0), and with 0–8% (w/v) NaCl (optimum, 0%). In the presence of sulfide and bicarbonate, acetate, butyrate, yeast extract, lactate, malate, pyruvate, succinate, and fumarate promoted growth. The DNA G + C content was 62.9–63.0 mol%. While the 16S rRNA gene sequences confirmed that the new strains belonged to the genus Ectothiorhodospira of the Ectothiorhodospiraceae, comparison of the genome nucleotide sequences of strains B14B, A-7R, and A-7Y revealed that the new isolates were remote from all described Ectothiorhodospira species both in dDDH (19.7–38.8%) and in ANI (75.0–89.4%). The new strains are also genetically differentiated by the presence of a nitric oxide reduction pathway that is lacking from all other Ectiothiorhodospiraceae. We propose to assign the isolates to the new species, Ectothiorhodospira lacustris sp. nov., with the type strain B14BT (=DSM 116064T = KCTC 25542T = UQM 41491T).

Efficacy of Ciprofloxacin and Amoxicillin Removal and the Effect on the Biochemical Composition of Chlorella vulgaris.

Antibiotics are frequently detected in the aquatic environment due to their excessive usage and low-efficiency removal in wastewater treatment plants. This can provide the origin to the development of antibiotic-resistant genes in the microbial community, with considerable ecotoxicity to the environment. Among the antibiotics, the occurrence of ciprofloxacin (CIP) and amoxicillin (AMX) has been detected in various water matrices at different concentrations around the Earth. They are designated as emerging contaminants (ECs). Microalga Chlorella vulgaris (C. vulgaris) has been extensively employed in phycoremediation studies for its acclimatization property, non-target organisms for antibiotics, and the production of value-added bioproducts utilizing the nutrients from the wastewater. In this study, C. vulgaris medium was spiked with 5 mg/L of CIP and AMX, and investigated for its growth-stimulating effects, antibiotic removal capabilities, and its effects on the biochemical composition of algal cells compared to the control medium for 7 days. The results demonstrated that C. vulgaris adapted the antibiotic spiked medium and removed CIP (37 ± 2%) and AMX (25 ± 3%), respectively. The operating mechanisms were bioadsorption, followed by bioaccumulation, and biodegradation, with an increase in cell density up to 46 ± 3% (CIP) and 36 ± 4% (AMX), compared to the control medium. Further investigations revealed that, in the CIP stress-induced algal medium, an increase in major photosynthetic pigment chlorophyll-a (30%) and biochemical composition (lipids (50%), carbohydrates (32%), and proteins (65%)) was observed, respectively, compared to the control medium. In the AMX stress-induced algal medium, increases in chlorophyll-a (22%), lipids (46%), carbohydrates (45%), and proteins (49%) production were observed compared to the control medium. Comparing the two different stress conditions and considering that CIP is more toxic than AMX, this study provided insights on the photosynthetic activity and biochemical composition of C. vulgaris during the stress conditions and the response of algae towards the specific antibiotic stress. The current study confirmed the ability of C. vulgaris to adapt, bioadsorb, bioaccumulate, and biodegrade emerging contaminants. Moreover, the results showed that C. vulgaris is not only able to remove CIP and AMX from the medium but also can increase the production of valuable biomass usable in the production of various bioproducts.

A comprehensive study on the exposure of nanoplastics to constructed wetland ecological systems: Macrophyte physiology and microbial enzymology, community composition and metabolic functions

The increasing emissions of nanoplastics inevitably pose a potential threat to constructed wetland (CWs) ecosystems. However, to our knowledge, the studies on the impact of nanoplastics on CWs were mainly for the effect on nitrogen removal, but comprehensive research on wetlands is still lacking. Thus, we revealed the overall effects of polystyrene nanoparticles (PSNPs) on wastewater treatment performance, and separate exploration of macrophytes and microbes. Results showed that although 1 and 10 mg/L PSNPs had little influences on COD removal, they caused serious suppression in TN removal, and 10 mg/L PSNPs negatively affected the NH4+-N and TP removal. These suppressions were due to the accumulation of>97% PSNPs attached to the sand biofilm, which proved that CWs could effectively remove nanoplastics. As for macrophyte physiology, PSNPs significantly affected the activities of superoxide dismutase, catalase, peroxidase, and the content of malondialdehyde in each phase. The major photosynthetic pigment biosynthesis was inhibited with 10 mg/L PSNPs. Furthermore, the soil catalase activities and the relative abundances of main antioxidant enzymes were obviously impacted. Caused by excess nanoplastic-induced ROS, almost all activities of dehydrogenase, phosphatase, ammonia monooxygenase, nitrate reductase were significantly inhibited. As for metagenomics analysis, taxonomy annotation revealed that PSNPs negatively affected the major functional bacteria involved in global geochemical nitrogen, phosphorus and sulfur cycle. Functional annotation analysis revealed that some indispensable metabolism pathways (oxidative phosphorylation, pyruvate metabolism, ABC transporter, two-component system, biofilm formation, etc.) were also inhibited. Additionally, nanoplastics reduced the overall pattern of genes related to nitrogen metabolism and partial genes in glucose degradation. Overall, our results comprehensively indicate that nanoplastic is a potential danger to wetland ecosystems and should receive more attention.

Photosynthetic pigments of co-occurring Northeast Atlantic Laminaria spp. are unaffected by decomposition

Along Northeast Atlantic coasts, the genus Laminaria dominates kelp forests. Two species, L. digitata and L. hyperborea, are cold temperate whilst the third, L. ochroleuca, is warm temperate. In northern France and the southern British Isles, all 3 species now co-occur, with a gradual rise in predominance of L. ochroleuca evident over recent decades due to climate-driven range shifts. Despite recent focus on the export of photosynthetically viable macroalgal detritus, the effect of decomposition on detrital pigment concentration remains unknown for northern hemisphere kelps. Furthermore, notwithstanding their importance in determining habitat suitability, the photosynthetic pigments of all 3 species have not yet been assessed comparatively within the same forest. Here, we present results of a field experiment aimed to test potential changes in the pigments of decomposing kelp blade fragments. Using spectrophotometry and Gaussian peak spectral deconvolution to quantify pigments, we found that shallow benthic decomposition over 1 mo did not affect major photosynthetic pigment concentrations in any of the examined species. Moreover, the 2 boreal species were similar in their sporophyte pigment stoichiometry and had more chlorophyll a, chlorophyll c, fucoxanthin and minor carotenoids (β,β-carotene and zeaxanthin) than L. ochroleuca. This resulted in total pigment content that was 82 and 74% higher in L. digitata and L. hyperborea than in L. ochroleuca. These differences correspond approximately to each species’ latitudinal distribution and photosynthetic performance. Our results suggest photosynthetic viability of Northeast Atlantic kelp in the initial detrital phase and a potential reduction of forest-scale photosynthetic capacity under continued ocean warming.

High-temperature resistance of the thin-blade strain of Pyropia haitanensis and its pilot cultivation in mariculture farm

The characteristics of the thin-blade strain (HR-5) were evaluated and compared with the wild type strain (WT) in Pyropia haitanensis in laboratory studies and pilot scale tests in a mariculture farm. The results showed that, at the suitable temperature (23 °C) and high temperature (27 and 29 °C) for 7 days, the survival rates of conchospores were 86.6, 73.5, and 42% in HR-5, which were 3.0, 13.3, and 3.2% higher than those of WT, respectively, but showing no significant difference between them (P > 0.05). When the F1 gametophytic blade of HR-5 and WT were first cultured at 23 °C for 25 days and then cultured at 23, 27, and 29 °C for another 20 days, the mean blade length increased by 13.1, 8.7, and 6.4 times for HR-5, and only 8.9, 4.6, and 3.5 times for WT compared with the original lengths, respectively. Three blade harvests were done in sea cultivation, and the mean wet weight of HR-5 blades was 0.17, 0.27, and 0.42 g per blade, which were 142.9, 49.2, and 38.3% higher than those of WT, respectively, showing significant differences between them (P < 0.05); the mean thickness of HR-5 blades was 26.0, 28.5, and 29.6 μm, decreasing by 31.9, 40.2, and 46.5% in contrast with that of WT, respectively, showing highly significant differences between them (P < 0.01); the phycobiliprotein content of HR-5 blades was 80.6, 75.3, and 61.8 mg g−1, increased by 12.2, 26.0, and 30.9% in contrast with that of WT, respectively. The results confirmed that the high-temperature resistance of HR-5 conchospores was similar to WT, while the blades of HR-5 were thinner and grew faster with higher contents of the major photosynthetic pigments as compared with WT. It therefore has the potential to be developed into a new variety with thin thallus suitable for cultivation along the coast of South China and promote the transformation and development of the industry of P. haitanensis.

Prosthecochloris marina sp. nov., a new green sulfur bacterium from the coastal zone of the South China Sea.

A Gram-negative, anaerobic photoautotroph, nonmotile, oval bacterium possessing gas vesicles and having no prosthecae, designated as V1, was isolated from the South China Sea coastal zone. It had chlorosomes as photosynthetic structures, and bacteriochlorophyll c as the major photosynthetic pigment. The strain was found to grow at 20-35°C, pH 6.3-8.0 (optimum, pH 7.1) and with 0.7-5.8% (w/v) NaCl (optimum, 1-1.8%). In the presence of sulfide and bicarbonate, acetate, and fructose promoted growth. The DNA G+C content was 47mol%. While the new isolate belonged to the Chlorobiaceae genus Prosthecochloris, it exhibited low similarity of the 16S rRNA gene sequences (96.21-96.78%) to other members of this genus. Comparison of the genome nucleotide sequences of strain V1 revealed that the new isolate was remote from the Chlorobiaceae type strains both in dDDH (16.8-18.9%) and in ANI (75.2-77.8%). We propose to assign the isolate to a new species, Prosthecochloris marina sp. nov., with the type strain V1T ( = VKM-3301T = KCTC 15824T).

Interaction of Zinc Oxide and Copper Oxide Nanoparticles with Chlorophyll: A Fluorescence Quenching Study

The present study aims to investigate the interactions of zinc oxide nanoparticles and copper oxide nanoparticles with the major photosynthetic pigment chlorophyll using ultraviolet-visible, steady state, and time resolved laser induced fluorescence spectroscopy. The steady state fluorescence measurements show that zinc oxide and copper oxide nanoparticles quench the fluorescence of chlorophyll in concentration-dependent manner. The Stern-Volmer plot for the chlorophyll-zinc oxide nanoparticles is linear, and the value of quenching constant has been observed to increase with temperature indicating the possibility of dynamic quenching. A decrease in the lifetime of chlorophyll with increase in the concentration of zinc oxide nanoparticles confirms the involvement of dynamic quenching in the chlorophyll–zinc oxide nanoparticle interaction. In the case of copper oxide nanoparticles, the Stern-Volmer plot deviates from linearity observed in the form of upward curvature depicting the presence of both static and dynamic quenching. In addition, the lifetime of chlorophyll decreases with increase in the concentration of copper oxide nanoparticles displaying the dominance of dynamic quenching in the chlorophyll-copper oxide nanoparticle interaction. The decrease observed in the value of binding constant with increasing temperature and negative values of change in enthalpy, entropy, and Gibb’s free energy indicates that van der Waal and hydrogen bonding are the prominent forces during the interaction of chlorophyll with both zinc oxide and copper oxide nanoparticles and that the process is spontaneous and exothermic. The interaction of zinc oxide and copper oxide nanoparticles with chlorophyll occurs through electron transfer mechanism. The obtained results are useful in understanding the sensitization processes involving chlorophyll and zinc oxide and copper oxide nanoparticles.

Phycobilins and Phycobiliproteins Used in Food Industry and Medicine.

Open tetrapyrroles termed phycobilins represent the major photosynthetic accessory pigments of several cyanobacteria and some eukaryotic algae such as the Glaucophyta, Cryptophyta and Rhodophyta. These pigments are covalently bound to so-called phycobiliproteins which are in general organized into phycobilisomes on the thylakoid membranes. In this work we first briefly describe the physico-chemical properties, biosynthesis, occurrence, in vivo localization and roles of the phycobilin pigments and the phycobiliproteins. Then the potential applications and uses of these pigments, pigment-protein complexes and related products by the food industry (e.g., as LinaBlue® or the so-called spirulina extract used as coloring food), by the health industry or as fluorescent dyes are critically reviewed. In addition to the stability, bioavailability and safety issues of purified phycobilins and phycobiliproteins, literature data about their antioxidant, anticancer, anti-inflammatory, immunomodulatory, hepatoprotective, nephroprotective and neuroprotective effects, and their potential use in photodynamic therapy (PDT) are also discussed.

Imhoffiella gen. nov., a marine phototrophic member of the family Chromatiaceae including the description of Imhoffiella purpurea sp. nov. and the reclassification of Thiorhodococcus bheemlicus Anil Kumar et al. 2007 as Imhoffiella bheemlica comb. nov.

A coccoid-shaped phototrophic purple sulfur bacterium, strain AK35T, was isolated from a coastal surface water sample collected from Visakhapatnam, India. Cells were Gram-stain-negative, motile and purple, containing bacteriochlorophyll a and the carotenoid rhodopinal as major photosynthetic pigments. Strain AK35T was able to grow photoheterotrophically and could utilize a number of organic substrates. It was unable to grow photoautotrophically. Strain AK35T was able to utilize sulfide and thiosulfate as electron donors. The main fatty acids present were identified as C16 : 0, C18 : 1ω7c, and C16 : 1ω7c and/or iso-C15 : 0 2OH (summed feature 3). Strain AK35T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and six unidentified lipids as polar lipids. The G+C content of the DNA of strain AK35T was 63.1 mol%. 16S rRNA gene sequence comparisons indicated that the isolate represented a member of the family Chromatiaceae. 16S rRNA gene sequence analysis indicated that strain AK35T is phylogenetically distinctly positioned outside the groups of most members of the genus Thiorhodococcus, clustered with members of the genera Marichromatium and Phaeochromatium, but was most closely related to Thiorhodococcus bheemlicus with a pairwise sequence similarity of 98.75 %. Based on DNA-DNA hybridization between strain AK35T and Thiorhodococcus bheemlicus MTCC 8120T a relatedness of 39.46 % was established. Distinct morphological, physiological and genotypic differences from these previously described taxa supported the classification of the new isolate as a representative of a novel species in a new genus, for which the name Imhoffiella purpurea gen. nov., sp. nov. is proposed. The type strain of Imhoffiella purpurea is AK35T (=JCM 18851T=KCTC 15575T=MTCC 12304T). In addition, Thiorhodococcus bheemlicus is recognized as another species of this genus and transferred to Imhoffiella bheemlica comb. nov.

Fast detection of leaf pigments and isoprenoids for ecophysiological studies, plant phenotyping and validating remote-sensing of vegetation.

Rapid developments in remote-sensing of vegetation and high-throughput precision plant phenotyping promise a range of real-life applications using leaf optical properties for non-destructive assessment of plant performance. Use of leaf optical properties for assessing plant performance requires the ability to use photosynthetic pigments as proxies for physiological properties and the ability to detect these pigments fast, reliably and at low cost. We describe a simple and cost-effective protocol for the rapid analysis of chlorophylls, carotenoids and tocopherols using high-performance liquid chromatography (HPLC). Many existing methods are based on the expensive solvent acetonitrile, take a long time or do not include lutein epoxide and α-carotene. We aimed to develop an HPLC method which separates all major chlorophylls and carotenoids as well as lutein epoxide, α-carotene and α-tocopherol. Using a C30 -column and a mobile phase with a gradient of methanol, methyl-tert-butyl-ether (MTBE) and water, our method separates the above pigments and isoprenoids within 28 min. The broad applicability of our method is demonstrated using samples from various plant species and tissue types, e.g. leaves of Arabidopsis and avocado plants, several deciduous and conifer tree species, various crops, stems of parasitic dodder, fruit of tomato, roots of carrots and Chlorella algae. In comparison to previous methods, our method is very affordable, fast and versatile and can be used to analyze all major photosynthetic pigments that contribute to changes in leaf optical properties and which are of interest in most ecophysiological studies.

Isolation and characterization of an improved strain of Porphyra chauhanii (Bangiales, Rhodophyta) with high-temperature resistance

The blades of the wild-type strain of Porphyra chauhanii (PC-WT) were irradiated with 60Co-γ rays and cultured at high temperature (30 °C) for 25 days. The surviving somatic cells of the irradiated blades were isolated enzymatically and were regenerated into whole blades and screened at high temperature. Vigorously growing blades at high temperature were selected and individually proliferated. A genetically homozygous and free-living conchocelis strain of TR-5 was obtained through parthenogenesis. Subsequently, TR-5 was compared with PC-WT for high-temperature resistance, growth, contents of major photosynthetic pigments, and the releasing ability of monospores and conchospores. The results showed that the survival percentage, division, and rhizoid germination of conchospores were not significantly different between TR-5 and PC-WT at 18 and 23 °C; but the survival percentages were 261.2 and 329.3 % higher, the division percentages were 42.8 and 72.6 % higher, and the rhizoid germination percentages were 94.3 and 199.5 % higher in the former than in the latter at 27 and 29 °C, respectively. When F1 gametophytic blades of TR-5 and PC-WT were firstly cultured at 23 °C for 30 days, and then cultured at 18, 23, and 27 °C for another 10 days, the absolute growth rates of TR-5 blades were 4.4, 4.3, and 10.4 times those of PC-WT and the relative growth rates were 1.1, 1.1, and 2.0 times those of PC-WT, respectively. The apical and middle parts of PC-WT blades were disintegrated due to the release of a large number of monospores after culturing for 15 days at 27 °C or 10 days at 29 °C, and only the basal parts of the blades remained intact. On the other hand, TR-5 blades grew rapidly with normal color and shape without releasing monospores and were slightly curled, even after being cultured for an additional 30 days. In addition, the contents of three major photosynthetic pigments (chlorophyll a (Chl. a), phycoerythrin (PE), and phycocyanin (PC)) and the conchospore numbers in TR-5 at a suitable temperature (23 °C) were 66.7, 244.2, 115.7, and 92.0 % higher than those of PC-WT, respectively. Meanwhile, the blades of TR-5 were 23.2 % thinner than those of PC-WT. The results indicated that TR-5 has thinner blade, higher contents of the major photosynthetic pigments, faster growth speed, higher temperature resistance, has larger number of conchospores released, and no monospore release as compared with PC-WT. It therefore has potential to be developed into a new variety suitable for cultivation in the aquaculture areas with high temperature in the coast of South China.

A comparative analysis of fatty acid composition and fucoxanthin content in six Phaeodactylum tricornutum strains from diff erent origins

Phaeodactylum tricornutum is a potential livestock for the combined production of eicosapentaenoic acid (EPA) and fucoxanthin. In this study, six marine diatom strains identified as P. tricornutum were cultured and their total lipid, fatty acid composition and major photosynthetic pigments determined. It was found that the cell dry weight concentration and mean growth rate ranged between 0.24–0.36 g/L and 0.31–0.33/d, respectively. Among the strains, SCSIO771 presented the highest total lipid content, followed by SCSIO828, and the prominent fatty acids in all strains were C16:0, C16:1, C18:1, and C20:5 (EPA). Polyunsaturated fatty acids, including C16:2, C18:2, and EPA, comprised a significant proportion of the total fatty acids. EPA was markedly high in all strains, with the highest in SCSIO828 at 25.65% of total fatty acids. Fucoxanthin was the most abundant pigment in all strains, with the highest in SCSIO828 as well, at 5.50 mg/g. The collective results suggested that strain SCSIO828 could be considered a good candidate for the concurrent production of EPA and fucoxanthin.

Phaeobacterium nitratireducens gen. nov., sp. nov., a phototrophic gammaproteobacterium isolated from a mangrove forest sediment sample

A novel brown-coloured, Gram-negative-staining, rod-shaped, motile, phototrophic, purple sulfur bacterium, designated strain AK40T, was isolated in pure culture from a sediment sample collected from Coringa mangrove forest, India. Strain AK40T contained bacteriochlorophyll a and carotenoids of the rhodopin series as major photosynthetic pigments. Strain AK40T was able to grow photoheterotrophically and could utilize a number of organic substrates. It was unable to grow photoautotrophically and did not utilize sulfide or thiosulfate as electron donors. Thiamine and riboflavin were required for growth. The dominant fatty acids were C12 : 0, C16 : 0, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The polar lipid profile of strain AK40T was found to contain diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and eight unidentified lipids. Q-10 was the predominant respiratory quinone. The DNA G+C content of strain AK40T was 65.5 mol%. 16S rRNA gene sequence comparisons indicated that the isolate represented a member of the family Chromatiaceae within the class Gammaproteobacteria. 16S rRNA gene sequence analysis indicated that strain AK40T was closely related to Phaeochromatium fluminis, with 95.2% pairwise sequence similarity to the type strain; sequence similarity to strains of other species of the family was 90.8-94.8%. Based on the sequence comparison data, strain AK40T was positioned distinctly outside the group formed by the genera Phaeochromatium, Marichromatium, Halochromatium, Thiohalocapsa, Rhabdochromatium and Thiorhodovibrio. Distinct morphological, physiological and genotypic differences from previously described taxa supported the classification of this isolate as a representative of a novel species in a new genus, for which the name Phaeobacterium nitratireducens gen. nov., sp. nov. is proposed. The type strain of Phaeobacterium nitratireducens is AK40T ( = JCM 19219T = MTCC 11824T).

Facile transformation of the five-membered exocyclic E-ring in 132-demethoxycarbonyl chlorophyll derivatives by molecular oxygen with titanium oxide in the dark

Major photosynthetic pigments chlorophyll(Chl)s have a cyclic tetrapyrrole with a five-membered exocyclic E-ring as photofunctional moieties. Its transformation is one promising methodology to develop functional pigments based on Chl chemistry. This paper report a facile conversion from Chl derivatives lacking the 132-methoxycarbonyl moiety to the corresponding chlorophyllous pigments, whose exocyclic E-ring had two oxo groups at the 131- and 132-positions, by contact with the TiO 2 particles in the presence of molecular oxygen in the dark. The conversion proceeded under mild conditions without hydrolysis of the ester group in the 17-propionate residue. This is in sharp contrast to the inevitable ester cleavage in the conventional synthesis of Chl derivatives that possess α-diketone in the E-ring. The reaction properties in the present method allowed us to perform a one-step conversion of Chl derivatives esterified with a natural isoprenoid alcohol phytol to the corresponding 132-oxo-pigments. No removal of central Zn from the chlorin macrocycle occurred in the present conversions using Zn pyropheophytin a as a starting material.

Relationships between Nutrients and Chlorophyll a Concentration in the International Alma Gol Wetland, Iran

This study investigated the relationships between nutrients and chlorophyll, a concentration in the International Alma Gol Wetland. Chlorophyll a is the major photosynthetic pigment in lots of phytoplanktons and has been used as a trophy index in aquatic ecosystems. Water samples were collected fortnightly from five stations in the wetland during summer and autumn. Chlorophyll-a ranged between 4.38 to 156.55 mg/m 3 , sulfate ranged between 138 to 190 mg/l, total alkalinity ranged between 80 to 280 mg/l, silica ranged between 3.80 to 35.00 mg/l, phosphate ranged between 0.02 to 3.70 mg/l, ammonia ranged between 0.10 to 11.90 mg/l, nitrate ranged between 0.01 to 2.75 mg/l and nitrite ranged between 0.01 to 0.39 mg/l. There was a significant correlation between chlorophyll a and nitrate, nitrite and ammonia but there was no significant correlation between chlorophyll a and silica, total alkalinity, sulfate and phosphorus.

Subsurface Associations of Acaryochloris-Related Picocyanobacteria with Oil-Utilizing Bacteria in the Arabian Gulf Water Body: Promising Consortia in Oil Sediment Bioremediation

Two picocyanobacterial strains related to Acaryochloris were isolated from the Arabian Gulf, 3m below the water surface, one from the north shore and the other from the south shore of Kuwait. Both strains were morphologically, ultrastructurally, and albeit to a less extend, phylogenetically similar to Acaryochloris. However, both isolates lacked chlorophyll d and produced instead chlorophyll a, as the major photosynthetic pigment. Both picocyanobacterial isolates were associated with oil-utilizing bacteria in the magnitude of 10(5) cells g(-1). According to their 16S rRNA gene sequences, bacteria associated with the isolate from the north were affiliated to Paenibacillus sp., Bacillus pumilus, and Marinobacter aquaeolei, but those associated with the isolate from the south were affiliated to Bacillus asahii and Alcanivorax jadensis. These bacterial differences were probably due to environmental variations. In batch cultures, the bacterial consortia in the nonaxenic biomass as well as the pure bacterial isolates effectively consumed crude oil and pure aliphatic and aromatic hydrocarbons, including very high-molecular-weight compounds. Water and diethylether extracts from the phototrophic biomass enhanced growth of individual bacterial isolates and their hydrocarbon-consumption potential in batch cultures. It was concluded that these consortia could be promising in bioremediation of hydrocarbon pollutants, especially heavy sediments in the marine ecosystem.

THE LIPID-PIGMENT COMPLEX COMPONENTS OF WINTER WHEAT LEAVES AT INOCULATION WITH MICROORGANISMS POSESSING PHOSPHATMOBILIZATION ABILITY

The evaluation of the physiological condition of winter wheat plants inoculated with phosphate mobilizing microorganisms under the phosphorus deficiency conditions was performed. The influence of PaenibacilluspolymyxaKB,Rhizobiumradiobacter1333andRhizobium radiobacter 5006 on lipid-pigment complexes of plants was observed. The accumulation of the major photosynthetic pigments, increasing of chlorophyll (a+b)/carotenoids ratio and maintaining of high level of phosphatidyl glycerol and stable content of sulphoquinovosyl diacylglycerol was revealed. The inoculation of seeds with phosphate mobilizing microorganisms had significantly improved the productivity of wheat plants in all variants with its highest indices at seeds bacterization with Rhizobium radiobacter 5006.

Cryopreservation of the Chlorophyll d-Containing Cyanobacterium Acaryochloris Marina

Cryopreservation of a prokaryotic alga, Acaryochloris marina, which was first isolated as a minor symbiont from a colonial ascidian, was investigated. This alga, possessing chlorophyll d as the major photosynthetic pigment, is an important organism for elucidating various biological questions such as the mechanism of chlorophyll diversity and the evolution of photosynthesis. However, the proportion of photosynthetic pigments changes on serial subcultures on maintenance under a fluorescent lamp, a light condition that differs from that of the original habitat. Cryopreservation has the capacity to ensure the maintenance of the physiological and genetic stability of A. marina. By placing samples in a styrene foam container in a deep freezer, cooling rate of –2 °C·min-1 was obtained for pre-freezing to –80 °C prior to plunging into liquid nitrogen. Amongst the three distinct cryoprotectants employed, [dimethyl sulfoxide (DMSO, 10% v/v), methanol (10% v/v), and glycerol (10% v/v)], DMSO was the most effective since cells preserved in DMSO for one month in liquid nitrogen or at –80 °C in a deep freezer, started to grow 200 h after inoculation at 20 °C under a fluorescent lamp. In contrast, no cell growth was observed when cells were preserved employing methanol, and growth of contaminant bacteria was observed when cells were preserved in glycerol. The optimum concentration of DMSO was 10%. Other concentrations of DMSO resulted in an extended lag period at 5% and 20% DMSO, and growth was completely inhibited at 40% DMSO.

Quantitative analysis of pigment gene expression in pigment mutants ofPorphyra haitanensis

Phycoerythrin (PE), phycocyanin (PC), allophycocyanin (APC), and chlorophyll a(Chl.a) are the four major photosynthetic pigments of Porphyra haitanensis. Their contents and ratio determine the blade color of Porphyra. In this study, the relative expressed levels of four pigment genes (Cpeα, Cpcα, Apcβ, and Chl.a) in different growth phases (early phase, bloom phase, and final phase) were determined using quantitative real-time PCR (qPCR) in one wild line and six pigment mutant lines of P. haitanensis. In all the lines, the relative expression levels of the four pigment genes were in the sequence: ApcβCpcα Chl.aCpeα. The expressed level of Cpeα varied significantly in the different phases in all the lines; how-ever, the expressions of Cpcα, Apcβ, and Chl.a were stable in all phases in all lines. Furthermore, liner correlation and regression analysis indicated that the expression levels of the pigment genes had no relation to the pigment protein contents in any of the lines. In other words, the expression levels of the four pigment genes had no relation to the differences in blade color among the Porphyra lines. Based on these results, we speculate that the pigment mutation of P. haitanensis was induced by mutations in genes that affect the synthesis of the pigment proteins.