• ALGAE
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• v.24 no.2
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• pp.57-60
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• 2009

We described a freshwater filamentous zygnematacean species, Zygnema cruciatum (Vaucher) Agardh in Korea,based on light microscopy and scanning electron microscopy. Zygnema cruciatum is characterized by unbranched fil-amcnts of short cylindrical cells, two stellate chloroplasts per cell, a pyrenoid in each chloroplast. Cells are 32-39 $\mu$m in width and 35-50 $\mu$m in length, Conjugation is scalariform and female gametangia are cylindrical or slightlyenlarged. Zygospores are yellow-brown, spherical or broadly ovoid, 35-44 $\mu$m wide and 40-47 $\mu$m long. Under SEM, wall of zygospore has pitted mesospore and pits are 1.4-1.8 $\mu$m in diameter and 3-4 $\mu$m apart from each other.

• ALGAE
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• v.25 no.4
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• pp.197-204
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• 2010

Cytoskeletal changes were observed during cell division of the green alga Zygnema cruciatum using flourescein isothiocynate (FITC)-conjugated phallacidin for F-actin staining and FITC-anti-$\alpha$-tubulin for microtubule staining. Z. cruciatum was uninucleate with two star-shaped chloroplasts. Nuclear division and cell plate formation occurred prior to chloroplast division. Actin filaments appeared on the chromosome and nuclear surface during prophase, and the F-actin ring appeared as the cleavage furrow developed. FITC-phallacidin revealed that actin filaments were attached to the chromosomes during metaphase. The F-actin ring disappeared at late metaphase. At telophase, FITC-phallacidin staining of actin filaments disappeared. FITC-anti-$\alpha$-tubulin staining revealed that microtubules were arranged beneath the protoplasm during interphase and then localized on the nuclear region at prophase, and that the mitotic spindle was formed during metaphase. The microtubules appeared between dividing chloroplasts. The results indicate that a coordination of actin filaments and microtubules might be necessary for nuclear division and chromosome movement in Z. cruciatum.

• ALGAE
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• v.22 no.2
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• pp.125-129
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• 2007

Conventional methods for the isolation and purification of mRNA from Zygnema were unsuccessful because of its high amount of pigments and RNA interactive molecules. In particular, pigments were difficult to remove using conventional protocols because they interacted with RNA during pulverization of the materials. This resulted in total degeneration of RNA in two to three hours. To alleviate this problem, we developed an isolation method that utilized DEAE-cellulose resin. The pigments bound to DEAE anion exchange resin and separated from the RNA. Purified total RNA showed an yield of 50 μg per 100 mg of tissue with this method. The amplified 2nd strand cDNA was distributed 300 bp and over.