• ALGAE
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• 제22권2호
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• pp.87-93
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• 2007

Three ecotypes of the freshwater red alga Compsopogon coeruleus (Balbis) Montagne were recorded from different freshwater and brackish water habitats of Orissa state in the east coast of India. These three had persistent differences in their branching pattern, e.g. (i) acute angle between main axis and lateral branch, (ii) equal or near to right angle between main axis and lateral branch, and (iii) short spine-like outgrowth instead of a branch in older filaments, besides having differences in the length, breadth and thickness of cortex of the thallus. Morphological observation of these taxa, and the ecological characteristics of the habitat of their occurrence is presented.

• ALGAE
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• 제32권3호
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• pp.235-244
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• 2017

Freshwater algae living in shallow waters have evolved various photomovement to stay in the optimum light condition for survival. Previous action-spectra investigations showed that Spirogyra filaments have phototropic movement in blue light. To decipher the genetic control of phototropic movement, two phototropin homologues were isolated from Spirogyra varians, and named SvphotA and SvphotB. Both phototropins have similar molecular structure consisted of two light-oxygen-voltage domains (LOV1, LOV2) and a serine / threonine kinase domain. SvphotA and SvphotB had 48.7% sequence identity. Phylogenetic analysis showed SvphotA and SvphotB belong to different clades suggesting early divergence, possibly before the divergence of land plants from the Zygnematales. Quantitative PCR and northern blot analysis showed that SvphotA and SvphotB responded differently to red and blue light. SvphotA was consistently expressed in the dark and in blue light, while SvphotB was expressed only when the plants were exposed to light. When the filaments were exposed to red light, SvphotA was significantly downregulated whereas SvphotB was highly upregulated. These results suggest that the two phototropins may have different roles in the photoresponse in S. varians.

• ALGAE
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• 제22권2호
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• pp.131-139
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• 2007

The expression of genes responding to cold stress in a freshwater alga, Spirogyra varians, was studied by using differential expression gene (DEG) method. A gene strongly up-regulated in 4°C was isolated and designated as SVCR2 (Spirogyra varians cold regulated) gene. The cDNA encoding SVCR2 was cloned using λZAP cDNA library of Spirogyra varians. The deduced amino acid had a sequence similarity with trans-membrane protein in Arabidopsis thaliana (Q9M2D2, 52.7%). Northern blot analysis demonstrated that transcript level of SVCR2 increased about 10 fold under low temperature (4°C), compared with that cultured at warm (20°C) conditions. The expression of SVCR2 was also affected by light conditions. When the plants were exposed to high light (HL) (1200 μmol photon m–2 s–1), the expression of SVCR2 began within 2 hrs. This gene expression lasted for 4 hrs and decreased afterwards. Under the blue light (470 nm) condition, the expression of this gene was induced in same way as HL treatment, even under less than 100 μmol photon m–2 s–1. But red light (650 nm) and UV-A irradiation did not affect the expression of SVCR2.

• ALGAE
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• 제30권1호
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• pp.1-13
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• 2015

A new macroscopic riverine red algal species, Lemanea manipurensis sp. nov. (Batrachospermales) is described from Manipur in northeast India. It has a sparsely branched, pseudoparenchymatous thallus with a single, central axial filament that lacks cortical filaments. Spermatangia occur generally in isolated, low and indistinct patches or form an almost continuous ring around the axis. Carposporophytes project into the hollow thallus cavity without an ostiole. The most striking morphological feature is the carposporophyte with very short gonimoblast filaments having cylindrical, narrow and sparsely branched sterile filaments, the terminal cell of each branch with a single, large, elongate carpospore. The widely distributed L. fluviatilis has spherical carpospores in long branched chains. Phylogenetic analysis of rbcL sequence data and comparison with other Batrachospermales clearly show that our specimens do not align with other species of Lemanea and Paralemanea investigated thus far. Five specific names attributed in previous literature (1973-2014) to Lemanea from Manipur, L. australis, L. catenata, L. fluviatilis, L. mamillosa, and L. torulosa are rejected until critical anatomical and molecular evidence is available for specimens from the Manipur river systems. Taxa referable to Paralemanea were not confirmed for India in this study. In view of the high demand for food and medical uses of L. manipurensis in northeast India, conservation measures are needed for its long term survival. The present paper constitutes the first combined morphological / molecular study on a freshwater red alga from India.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.181-184
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• 2001

The biological fixation of carbon dioxide using microalgae have many advantages over chemicals and remove carbon dioxide simultaneously. A ketocarotenoid astaxanthin is hyper-accumulated in the green freshwater microalga, Haematococcus pluvialis. In the present study, the combine effects of carbon dioxide concentration and light intensity on the growth of H. pluvilais were investigated. The carbon dioxide concentration above 10% caused a severe inhibition and around 5% is optimal for growth. Adaptation to high concentration of carbon dioxide enhanced the $CO_2$ tolerance. Specific growth rate calculated differently based upon cell number or dry weight because of the distinctive life cycle patterns of H. pluvialis : small-sized motile green cell and thick cell walled red cyst cell. Based on the light dependence of H. pluvialis, internally illuminated air-lift photobioreactor was designed and operated. Gradual increase of light supply gave more active growth and more effective productivity of astaxanthin than constant light supply.

• ALGAE
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• 제29권2호
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• pp.101-109
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• 2014

Small red algae, especially those previously referred to as 'primitive' are often overlooked, but can be quite abundant. These 'primitive' red algae are now placed in several classes distinct from the Florideophyceae, for example the Stylonematophyceae. A brownish-red filamentous alga was collected from a sandy tide pool at Cape Tribulation, Queensland, Australia. Cultured specimens were identified as Bangiopsis and conformed to the morphological characters of the genus (multicellular base, erect filaments branched or unbranched, uniseriate to multiseriate-tubular, single multilobed purple-red to red-brown plastid with central pyrenoid, vegetative cells released directly as spores). Molecular data of two plastid genes (rbcL, psbA) support placement of the Australian isolate and isolates from India in Bangiopsis. The genetic variation between these isolates and isolates from Puerto Rico previously attributed to B. subsimplex indicates that these should be considered as a separate species. As the type locality is in the Atlantic Ocean, French Guiana, and not far from Puerto Rico, and the Puerto Rican isolate has been used often in phylogenetic analyses, we propose that the Indian and Pacific Ocean isolates be designated a new species, B. franklynottii, to acknowledge Ott's many years of research on inconspicuous freshwater and marine red algae. Our research also highlights the lack of careful descriptions in many of the records of this genus and the lack of morphological characters to distinguish species. Especially within the morphologically simple red algae, morphological distinctness does not necessarily reflect evolutionary divergences.