• Journal of Plant Biotechnology
• /
• 제49권4호
• /
• pp.271-291
• /
• 2022

Pectin methylesterase (PME) plays an important role in vegetative and reproductive development and biotic/abiotic stress responses by regulating the degree of methyl-esterification of pectic polysaccharides in the plant cell wall. PMEs are encoded by a large multigene family in higher land plant genomes. In general, the expression of plant PME genes shows tissue- or cell-specific patterns and is induced by endogenous and exogenous stimuli. In this study, we identified PME multigene family members (CsPMEs) from the sweet orange genome and report detailed molecular characterization and expression profiling in different citrus tissues and two fruit developmental stages. We also discussed the possible functional roles of some CsPME genes by comparing them with the known functions of PMEs from other plant species. We identified 48 CsPME genes from the citrus genome. A phylogenetic tree analysis revealed that the identified CsPMEs were divided into two groups/types. Some CsPMEs showed very close phylogenetic relationships with the PMEs whose functions were formerly addressed in Arabidopsis, tomato, and maize. Expression profiling showed that some CsPME genes are highly or specifically expressed in the leaf, root, flower, or fruit. Based on the phylogenetic relationships and gene expression profiling results, we suggest that some CsPMEs could play functional roles in pollen development, pollen tube growth, cross incompatibility, root development, embryo/seed development, stomata movement, and biotic/abiotic stress responses. Our results shed light on the biological roles of individual CsPME isoforms and contribute to the search for genetic variations in citrus genetic resources.

• 한국환경농학회지
• /
• 제24권1호
• /
• pp.6-11
• /
• 2005

A prototype surface flow constructed wetland was built in the upstream area of reclaimed tidal lands to improve the water quality of Lake Sihwa by treating severely polluted stream water. In this study, a tracer test using rhodamine-WT was performed to investigate the flow characteristics and to quantify the observed hydraulic residence time (HRT) for a high-lying cell in the Banwol wetland of the Sihwa constructed wetland. The tracer test indicated that even if flow was mainly observed in the open water area of the Banwol wetland, water flowed continuously in the vegetative area and there was no dead zone. The calculated HRT (51.3 hrs), calculated by dividing the wetland volume by the wetland inflow, exceeded the observed HRT (38.7 hrs), since the short-circuiting of flux resulting from irregular topography and vegetation was not reflected in the calculated HRT. The exit tracer concentration curves were reproduced well by both the plug flow with dispersion and tanks-in-series models, indicating that the performance of the Banwol wetland can be estimated accurately using these models.

• 환경생물
• /
• 제35권3호
• /
• pp.345-353
• /
• 2017

Detailed morphological studies and molecular analyses based on plastid-encoded rbcL gene sequences were undertaken on Peyssonnelia species, a poorly known genus from Korea. We report new records for the Korean coast, Peyssonnelia harveyana and P. rumoiana. Peyssonnelia harveyana is chiefly characterized by P. rubra-type anatomy, closely packed perithallial filaments in firm matrix, hypothallial filaments arranged in parallel rows, thalli with appressed margins, hypobasal calcification, and unicellular rhizoids. Peyssonnelia rumoiana is principally characterized by two vegetative features, hypothallial filaments arranged in a polyflabellate layer, and perithallial filaments arising from the whole upper surface of each hypothallial cell (Peyssonnelia rubra-type anatomy). Our rbcL analyses revealed that P. harveynana and P. rumoiana were placed within a clade of Peyssonnelia. We also propose the new combination, Sonderophycus cauliferus comb. nov., for previous Peyssonnelia caulifera. Phylogenetic analyses revealed that our S. cauliferus was placed within a clade of Sonderophycus.

• ALGAE
• /
• 제19권2호
• /
• pp.79-90
• /
• 2004

Nuclear DNA contents of spermatia from eight ceramiacean and four dasyacean algae (Ceramiales, Rhodophyta) and microspores from two land plants were estimated by fluorescence microscopic image processing and their nuclear SSU rDNA sequence data were analyzed. In frequency distribution patterns, the DAPI-stained nuclear volume (NV) of spermatia showed two peaks corresponding to 1C and 2C. Nuclear 2C DNA contents estimated from NV were 0.45-2.31 pg in ceramiacean and 0.40-0.57 pg in dasyacean algae and 8.42-9.51 pg in two land plants, Capsicum annuum and Nicotiana tabacum. By nuclear patterning of vegetative cells derived from an apical cell, 2C DNA contents of spermatia were 2.31 pg in an alga having uninucleate and non-polyploid nucleus (Aglaothamnion callophyllidicola), 0.45-1.94 pg in algae having uninucleate and polyploid nucleus (Antithamnion spp. and Pterothamnion yezoense), and 0.40-0.62 pg in algae having multinucleate and non-polyploid nuclei (Griffithsia japonica and dasyacean algae). Each mature spermatium and microspore (pollen grain) seemed to have a 2C nucleus, which may provide a genetic buffering system to protect the genetic content of a spermatium and microspore from potentially lethal mutations. Nuclear DNA content and SSU rDNA sequence of Antithamnion sparsum from Korea were reasonably different from those of Antithamnion densum from France. The data did not support the previous taxonomic studies that these two taxa could be conspecific.

• ALGAE
• /
• 제27권4호
• /
• pp.225-234
• /
• 2012

Zygnema is a conjugating filamentous green algal genus that is distributed in a broad range of freshwater habitats, from sea level to alpine summits. Although more than 150 species have been described worldwide, their taxonomy remains unclear, probably owing to their relatively simple morphology. We investigated the detailed morphology of Korean Zygnema species, combined with analysis of the plastid psbA gene from 22 specimens of the genus and putative relatives, in order to develope a key to their identification and isolation, and to determine their relationships. We recognized two species of Zygnema; Z. insigne and Z. leiospermum, based on morphological characters such as width of the vegetative cell, position of zygospores, dimensions and form of spores, shape of female gametangia, and color of mesospores. The analysis of psbA data was consistent with morphological comparison. The pairwise divergence between two species was 3.7-4.1% (34-38 bp) in psbA sequences. The phylogeny of psbA revealed the monophyly of Z. insigne and Z. leiospermum together with two isolates of Z. circumcarinatum from Germany and Scotland. This is the first report on the psbA gene phylogeny of Zygnema.

• Journal of Microbiology and Biotechnology
• /
• 제1권1호
• /
• pp.37-44
• /
• 1991

A shuttle promoter-probe vector, pEB203, was derived from pBR322, pPL703 and pUB110. Using the vector, a useful DNA fragment, 319 bp EcoRI fragment, having strong promoter activity has been cloned from Bacillus subtills chromosomal DNA. Selection was based on chloramphenicol resistance which is dependent upon the introduction of DNA fragments allowing expression of a chloramphenicol acetyl transferase gene. The nucleotide sequence of the 319 bp fragment has been determined and the putative -35 and -10 region, ribosome binding site, and ATG initiation codon were observed. This promoter was named EB promoter and the resultant plasmid which can be used as an expression vector was named pEBP313. The crystal protein gene from B. thuringiensis subsp. kurstaki HD-73 was cloned downstream from the EB promoter without its own promoter. When the resultant plasmid, pBT313, was introduced into Escherichia coli and B. subtilis, efficient synthesis of crystal protein was observed in both cells, and the cp gene expression in B. subtilis begins early in the vegetative phase. The cell extracts from both clones were toxic to Hyphantria cunea larvae.

• Journal of Microbiology and Biotechnology
• /
• 제12권6호
• /
• pp.943-949
• /
• 2002

It has been proposed that chitin synthase 3 (CHS3)-nediated chitin synthesis during the vegetative cell cycle is regulated by chitin synthase 4 (CHS4) of Saccharomyces cerevisiae. To investigate direct protein-protein interaction between the coding products of these two genes, a domain of Chs3p that is responsible for interaction with Chs4p was identified, using the yeast two-hybrid system. This domain of 54 amino acids, termed MIRC3-4 (Maximum Interacting Region of Chs3p with Chs4p), is well conserved among CHS3 homologs of various fungi. Some mutations in MIRC3-4 resulted in a decrease in the enzymatic activity and chitin contents. Chs3p carrying those mutations exhibited weak interactions with Chs4p, when assayed by the yeast two-hybrid system. Surprisingly, all the mutants were sensitive to Calcofluor regardless of changes in enzymatic activities or chitin contents. This report deals with a core region in MIRC3-4 that affects the interaction with Chs4p.

• ALGAE
• /
• 제20권1호
• /
• pp.37-42
• /
• 2005

The morhology and life history of Stylonema cornu-cervi Reinsch from Japan were investigated. The species had multiseriate erect thalli from a basal cell. The thalli usually branched dichotomously, occasionally trichotomously near the base, and non-branched thalli were sometimes observed. A dichotomous branch on the upper portion near the base occurred only one time on each erect branch. Cells contained a stellate chloroplast, which was composed of a central rounded part with an obscure pyrenoid and 5-8 cup-like lobes connected to the central part by a small thin stipe. The biseriate part was observed on the six-celled stage in culture, and the grown thalli were multiseriate except for base and apices. Monospores forming from the immediate transformation of vegetative cells were observed. Thalli grew at 15-25$^{\circ}C$ and died at 10 and 30$^{\circ}C$. The fastest growth and maturation were observed under 25$^{\circ}C$ and 14L:10D. Although S. alsidii (Zanardini) Drew usually had uniseriate thalli, irregularly branched multiseriate thalli had been reported in cultures. It is possible that in the previous report the thalli were confused with S. cornu-cervi. In this report, S. cornu-cervi were distinguished from S. alsidii in that the branches were few, the multiseriate portions were observed on the early stage (six-celled stage), and the grown thalli were multiseriate except at the base and apices.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권3호
• /
• pp.167-172
• /
• 2001

Staphylokinase (SAK) was produced in B. subtilis using two different promoter systems, i.e. the P43 and sacB promoters. To maximize SAK expression in B. subtilis, fermentation control strategies for each promoter were examined. SAK, under P43, a vegetative promoter transcribed mainly by $\sigma$(sup)B containing RNA polymerase, was overexpressed at low dissolved oxygen (D.O.) levels, suggesting that the sigB operon is somewhat affected by the energy charge of the cells. The expression of SAK at the 10% D.O. level was three times higher than that at the 50% D.O. level. In the case of sacB, a sucrose-inducible promoter, sucrose feeding was used to control the induction period and induction strength. Since sucrose is hydrolyzed by two sucrose hydrolyzing enzymes in the cell and culture broth, the control strategy was based on replenishing the loss of sucrose in the culture. With continuous feeding of sucrose, WB700 (pSAKBQ), which contains the SAK gene under sacB promoter, yielded ca. 35% more SAK than the batch culture. These results present efficient promoter-dependent control strategies in B. subtilis host system for foreign protein expression.

• Journal of Microbiology and Biotechnology
• /
• 제23권6호
• /
• pp.766-770
• /
• 2013

Several upstream activators required for proper activation of brlA are involved in the development, vegetative growth, toxin production, and pathogenesis of Aspergillus fumigatus. In this study, we characterized the roles of two upstream developmental regulators, A. fumigatus flbB (AfuflbB) and flbE (AfuflbE), in toxin production and virulence. The deletion of AfuflbB and AfuflbE resulted in reduction of the expression of AfulaeA. Moreover, only about 8% to 10% of fumagillin was produced in the two mutants compared with that of wild type, and ${\Delta}AfuflbB$ strain produced 85% of gliotoxin compared with wild type, whereas none was produced by ${\Delta}AfuflbB$. Flow-cytometric analysis revealed decreased necrotic and apoptotic polymorphonuclear leukocytes cell death after exposure to supernatants from ${\Delta}AfuflbB$ and ${\Delta}AfuflbB$ strains compared with the wild type. These results indicate that FlbB and FlbE are necessary for the proper laeA expression, toxin production, and virulence of A. fumigatus.