LCIB functions as a carbonic anhydrase: evidence from yeast and Arabidopsis carbonic anhydrase knockout mutants.

Chlamydomonas reinhardtii evolved a CO-concentrating mechanism (CCM) because of the limited CO in its natural environment. One critical component of the C. reinhardtii CCM is the limiting CO inducible B (LCIB) protein.

Arabidopsis plastid carbonic anhydrase βCA5 is important for normal plant growth.

Carbonic anhydrases (CAs) are zinc-metalloenzymes that catalyze the interconversion of CO2 and HCO3-. In heterotrophic organisms, CAs provide HCO3- for metabolic pathways requiring a carboxylation step. Arabidopsis (Arabidopsis thaliana) has 14 α- and β-type CAs, two of which are plastid CAs designated as βCA1 and βCA5.

A Rapid Method for Detecting Normal or Modified Plant and Algal Carbonic Anhydrase Activity Using .

In recent years, researchers have attempted to improve photosynthesis by introducing components from cyanobacterial and algal CO2-concentrating mechanisms (CCMs) into terrestrial C3 plants. For these attempts to succeed, we need to understand the CCM components in more detail, especially carbonic anhydrase (CA) and bicarbonate (HCO3−) transporters. Heterologous complementation systems capable of detecting carbonic anhydrase activity (i.

Molecular interaction of nitrate transporter proteins with recombinant glycinebetaine results in efficient nitrate uptake in the cyanobacterium Anabaena PCC 7120.

Nitrate transport in cyanobacteria is mediated by ABC-transporter, which consists of a highly conserved ATP binding cassette (ABC) and a less conserved transmembrane domain (TMD). Under salt stress, recombinant glycinebetaine (GB) not only protected the rate of nitrate transport in transgenic Anabaena PCC 7120, rather stimulated the rate by interacting with the ABC-transporter proteins. In silico analyses revealed that nrtA protein consisted of 427 amino acids, the majority of which were hydrophobic and contained a Tat (twin-arginine translocation) signal profile of 34 amino acids (1-34).

Mitochondrial carbonic anhydrases are needed for optimal photosynthesis at low CO2 levels in Chlamydomonas.

Chlamydomonas reinhardtii can grow photosynthetically using CO2 or in the dark using acetate as the carbon source. In the light in air, the CO2 concentrating mechanism (CCM) of C. reinhardtii accumulates CO2, enhancing photosynthesis.

Thylakoid localized bestrophin-like proteins are essential for the CO concentrating mechanism of .

The green alga possesses a CO concentrating mechanism (CCM) that helps in successful acclimation to low CO conditions. Current models of the CCM postulate that a series of ion transporters bring HCO from outside the cell to the thylakoid lumen, where the carbonic anhydrase 3 (CAH3) dehydrates accumulated HCO to CO, raising the CO concentration for Ribulose bisphosphate carboxylase/oxygenase (Rubisco). Previously, HCO transporters have been identified at both the plasma membrane and the chloroplast envelope, but the transporter thought to be on the thylakoid membrane has not been identified.

Physiological responses to salt stress of salt-adapted and directly salt (NaCl and NaCl+NaSO mixture)-stressed cyanobacterium Anabaena fertilissima.

Soil salinity in nature is generally mixed type; however, most of the studies on salt toxicity are performed with NaCl and little is known about sulfur type of salinity (NaSO). Present study discerns the physiologic mechanisms responsible for salt tolerance in salt-adapted Anabaena fertilissima, and responses of directly stressed parent cells to NaCl and NaCl+NaSO mixture. NaCl at 500 mM was lethal to the cyanobacterium, whereas salt-adapted cells grew luxuriantly.

Packed-bed column biosorption of chromium(VI) and nickel(II) onto Fenton modified Hydrilla verticillata dried biomass.

The present study represents the first attempt to investigate the biosorption potential of Fenton modified Hydrilla verticillata dried biomass (FMB) in removing chromium(VI) and nickel(II) ions from wastewater using up-flow packed-bed column reactor. Effects of different packed-bed column parameters such as bed height, flow rate, influent metal ion concentration and particle size were examined. The outcome of the column experiments illustrated that highest bed height (25cm); lowest flow rate (10mLmin(-1)), lowest influent metal concentration (5mgL(-1)) and smallest particle size range (0.

The freshwater cyanobacterium Anabaena doliolum transformed with ApGSMT-DMT exhibited enhanced salt tolerance and protection to nitrogenase activity, but became halophilic.

Glycine betaine (GB) is an important osmolyte synthesized in response to different abiotic stresses, including salinity. The two known pathways of GB synthesis involve: 1) two step oxidation of choline (choline → betaine aldehyde → GB), generally found in plants, microbes and animals; and 2) three step methylation of glycine (glycine → sarcosine → dimethylglycine → GB), mainly found in halophilic archaea, sulphur bacteria and the cyanobacterium Aphanothece (Ap.) halophytica.

Low cellular P-quota and poor metabolic adaptations of the freshwater cyanobacterium Anabaena fertilissima Rao during Pi-limitation.

Anabaena fertilissima is a filamentous freshwater N(2)-fixing cyanobacterium, isolated from a paddy field. Growth of the cyanobacterium was limited by the non-availability of inorganic phosphate (Pi) in the growth medium and was found to be directly related to the cellular P quota, which declined rapidly in Pi-deficient cells. To overcome Pi-deficiency, cells induced both cell-bound and cell-free alkaline phosphatase activities (APase).

Isolation and screening of phlD (+) plant growth promoting rhizobacteria antagonistic to Ralstonia solanacearum.

Tomato (Lycopersicon esculentum) is important widely grown vegetable in India and its productivity is affected by bacterial wilt disease infection caused by Ralstonia solanacearum. To prevent this disease infection a study was conducted to isolate and screen effective plant growth promoting rhizobacteria (PGPR) antagonistic to R. solanacearum.

Anabaena sp. PCC7120 transformed with glycine methylation genes from Aphanothece halophytica synthesized glycine betaine showing increased tolerance to salt.

Photosynthetic, nitrogen-fixing Anabaena strains play an important role in the carbon and nitrogen cycles in tropical paddy fields although they are salt sensitive. Improvement in salt tolerance of Anabaena cells by expressing glycine betaine-synthesizing genes is an interesting subject. Due to the absence of choline in cyanobacteria, choline-oxidizing enzyme could not be used for the synthesis of glycine betaine.

An alkaline phosphatase/phosphodiesterase, PhoD, induced by salt stress and secreted out of the cells of Aphanothece halophytica, a halotolerant cyanobacterium.

Alkaline phosphatases (APases) are important enzymes in organophosphate utilization. Three prokaryotic APase gene families, PhoA, PhoX, and PhoD, are known; however, their functional characterization in cyanobacteria largely remains to be clarified. In this study, we cloned the phoD gene from a halotolerant cyanobacterium, Aphanothece halophytica (phoD(Ap)).

Cyanobacteria: an emerging source for drug discovery.

The c group of Gram-negative gliding bacteria, has a long history of cosmopolitan occurrence. It has great biodiversity despite the absence of sexual reproduction. This wide biodiversity may be reflected in the wide spectrum of its secondary metabolites.

Microcystin producing cyanobacterium Nostoc sp. BHU001 from a pond in India.

The cyanobacterium Nostoc sp. BHU001 is a new isolate from a pond in India. The cyanobacterium produces more than ten peptides including five microcystin (MC) variants, MC-LR, -WR, -AR, -LA and methylated MC-LR, and a new peptide similar to cyanopeptolin.

Enrichment of sugar content in melon fruits by hydrogen peroxide treatment.

Since sweetness is one of the most important qualities of many fruits, and since sugars are translocated from leaves to fruits, the present study investigates photosynthetic activity, activity of sugar metabolizing enzymes, sugar content in leaves and fruits and endogenous levels of hydrogen peroxide in leaves of melon plants treated with various dilutions of hydrogen peroxide, a nonspecific signaling molecule in abiotic stress. For this purpose, 4-month-old melon plants were treated with various concentrations (<50mM) of hydrogen peroxide by applying 300 mL per day to the soil of potted plants. The treatments resulted in increased fructose, glucose, sucrose and starch in the leaves and fruits.

Allergenicity of airborne cyanobacteria Phormidium fragile and Nostoc muscorum.

In recent times, airborne microorganisms and their constituents have become prominent safety and health concern. Ongoing climatic changes coupled with unwarranted human activities have significantly deteriorated the ambient air quality. In certain environments, airborne algae contribute significantly to the total biological load of the atmosphere, hitherto dominated by bacteria and fungi.

Growth and cellular ion content of a salt-sensitive symbiotic system Azolla pinnata-Anabaena azollae under NaCl stress.

Salinity, at a concentration of 10 mM NaCl affected the growth of Azolla pinnata-Anabaena azollae association and became lethal at 40 mM. Plants exposed up to 30 mM NaCl exhibited longer roots than the control, especially during the beginning of incubation. Average root number in plants exposed to 10 and 20 mM NaCl remained almost the same as in control.

Diversity and seasonal variation of viable algal particles in the atmosphere of a subtropical city in India.

To characterize the airborne algal diversity in a populous subtropical urban environment, sampling was done at a height of 2.5m, the normal human breathing zone. Results indicated that airborne algae are the permanent constituent of Varanasi city atmosphere.

Phosphate metabolism in the cyanobacterium Anabaena doliolum under salt stress.

In the present study, we have investigated the effects of NaCl concentrations on the growth and phosphate metabolism of an Anabaena doliolum strain isolated from a paddy field, in order to determine the possible effects of salinization. Growth rate, chlorophyll content, and protein content decreased with increasing salt concentration in the growth medium, while carbohydrate concentration increased. Phosphate content and phosphate uptake rate decreased.