Academia Journal of Biology

Mitogen-activated protein kinase (MPK) cascades have emerged as a major signal transduction mechanism that connects diverse receptors or sensors to cellular and nuclear responses in eukaryotes. Although function and activation of some MPKs in response to stimuli have been studied in details, but substrates of these kinases were still poorly understood. Here, we provide that Arabidopsis MYB77 transcription factor, a R2R3-MYB protein, is a substrate of MPK3/6 in vitro. The MPK3, MPK6 and MYB77 proteins from Arabidopsis were expressed in Escherichia coli. Using in vitro phosphorylation assays we have identified that MYB77 was phosphorylated by recombinant MPK3/6. To identify the phosphorylation sites of MYB77 by MPK, purified MYB77 protein was phosphorylated by MPK, desalted and passed over TiO2 for improved phosphopeptide detection. This sample has been used to analysis for mass spectrometry. Seven phosphopeptides of MYB77 contained predictive MPKs phosphorylation sites (S-P motif) were analyzed by mass spectrometry. As results we identified four putative phosphorylation sites originated from 7 phosphopeptide peaks. Our results suggest that MYB77 is a novel substrate of MPK3/6 containing four phosphorylation sites in Arabidopsis.

Panax vietnamensis is one of the most valuable medicinal plants in Vietnam. In recent years, there has been an increasing interest in propagation and conservation of this plant. This paper attempts to show that direct somatic embryogenesis using the thin cell layer technique is an effective method for micropropagation of P. vietnamensis. This success was mainly resulting from the ability to develop into complete plants, together with the shortening of culture time. In this paper, three sources of explants (leaves, petioles and main roots) of 3-month-old in vitro plantlets of P. vietnamensis were cultured on MS medium supplemented with NAA and 2,4-D at various concentrations (0.1, 0.2, 0.5, 1.0 and 2.0 mg.l-1). After 10 weeks of culture, the results showed that among three types of explants used, leaf explants were optimal for direct somatic embryogenesis. Leaves cultured on MS medium supplemented with 2 mg.l-1 NAA gave the highest frequency of direct somatic embryogenesis. Histological study showed the normal development phases of somatic embryos of P. vietnamensis.

Diet is one of the important factors having strong effects on growth rate, survival rate and rearing efficiency of many fish species in general and Russian sturgeon in particular. In this study, three different diets (CT1-Artemia and processed; CT2-Lansy and Skerting; CT3-Artemia, Lansy and Tubifex worm) were experimented in order to identify the most suitable diets for rearing Russian sturgeon from the stages of fry to fingerling. The fish were reared in the raceway system in a period of four weeks. Results showed that the diets had strong effects on growth and survival rates of Russian sturgeon. In which, the fish were fed on the formula CT3 gave the highest absolute growth rate and final body weight (0.2 g/ind./day; 4.04 g/ind.), followed by the formula CT1 (0.17 g/ind./day; 3.52 g/ind.) and lowest at the formula CT2 (0.13 g/ind./day; 3.02 g/ind.) (P<0.05). Similarly, the fish were fed with the formula CT3 obtained higher relative growth and survival rates compared to those of the formula CT2 (54.59%; 69.33% as opposed to 42.6%; 37.67%; P<0.05). However, there were no significant differences about these two parameters between the formula CT3 and those of the formula CT1 (48.58%; 69%) (P>0.05). From the results of this study, it can be suggested that the formula CT3 was the most appropriate diet for rearing the Russian sturgeon from the stages of fry to fingerling under Lam Dong conditions.

Pueraria mirifica is a popular medicinal plant and is rich in phytoestrogens, especially isoflavonoids. The chalcone isomerase (CHI) gene is well-known as a key factor in biosynthetic pathways such as flavonoid, isoflavonoid, and anthocyanin biosynthesis. Among four CHI subfamilies, group IV remained largely uncharacterized in P. mirifica. By isolation and gene cloning, the CHI4A gene was amplified and sequenced. A dataset that included CHI4A genes from isolation, transcriptome, and Glycine max CHI4A was constructed for analysis. A total of 31 single nucleotide polymorphism (SNPs) was detected among sequences and 14 SNPs were found in P. mirifica subgroups. Thirteen SNPs changed the amino acid sequences of CHI4A genes; however, they do not affect core active residues in the protein structure. Two active sites typical for group 4 CHI in the Fabaceae family: Ile50 and Tyr106; and one conserved site Asn113, were found in this study, which is similar to the result of the previous study on CHI4. A three-dimensional protein model of isolated P. mirifica CHI4A enzyme was constructed with a high confidence level. The result provides more information about the variation and protein profile of the CHI4A gene for further experiments.

Căn cứ vào những mẫu vật thu thập được ở Vịnh Bắc Bộ và vùng biển ven bờ miền Bắc Việt Nam từ năm 1959 đến 1978, tác giả xác định được ở vịnh Bắc Bộ có 19 loài mực, thuộc 8 giống và 3 họ.Tác giả phân tích một số yếu tố sinh thái và tập tính sống của các loài mực có ảnh hưởng đến sản lượng khai thác.

Ampeliscid crustaceans and amphipods at all of the Vietnam Sea, up to present times have been poorly studied. Only two publications appeared in the past time, by results of some surveys carried out in Nha Trang Bay (Imbach, 1967) and in Bac Bo Gulf (Tonkin Gulf) (Margulis, 1968). Totally in these above publications,22 species of Ampelisca and 12 species of Byblis has been recorded, of these, many new species to science were described.The results of our taxonomical study on a great number of materials of benthic Ampeliscidae, collected from different representative localities of the nearshore waters of Vietnam in different times, has enlarged and adjusted the previous data, which give a comprehensive knowledge on the Ampeliscidae species composition of the Vietnam Sea.By geographical distribution aspect, fauna Amphipoda Ampeliscidae of Vietnam sea may be divided into 3 groups: 1. Group species cosmopolitan or enlarge distributed in Indo-Pacific region (Ampelisca cyclops, A. brevicornis,  A.  miops,  A. zimboangae  Byblis  rhinoceros,  B. mucronata...); 2.  Species with restricteddistribution in West Pacific region (Ampelisca bocki, A. misakiensis, A. misaharensis, A. iyoensis, Byblis io, B. pilosa, B. plumosa, B. pirloti, B. callisto...); 3. Species up to now found only in Vietnam Sea (Ampelisca dongnamensis, A. thaoae, Byblis caecus...).In this area, 11 species are newly recorded for the benthic Ampeliscidae fauna of the Vietnam Sea, of which 6 species are new to science (5 Ampelisca, 1 Byblis). Some remarks on the geographical distribution and taxonomical characteristics of the ampeliscid fauna of the Vietnam Sea are presented in the paper.

Bacillus subtilis has been a model for research on Gram-positive bacteria for more than four decades. It is a non-pathogenic bacterium and is conferred the GRAS (Generally Recognized As Safe) status by FDA. B. subtilis has also been widely used in the production of industrial proteins because of its high secretion capacity into the culture medium. To enhance the utility of B. subtilis in protein expression system, the pHT vectors with strong promoter Pgrac were constructed. This promoter is based on the strong σA-dependent promoter preceding the groELS operon of B. subtilis fused with the lac operator (lacO) of Escherichia coli, which allows a target protein to be expressed up to 16% of total intracellular proteins. In the previous study, amyQ gene encoding reporter α-amylase (AmyQ) from Bacillus amyloliquefaciens fused with Pgrac promoter to construct the secretional expression plasmid pHT43-amyQ (Pgrac-amyQ) and expressed fairly good in B. subtilis. In this study, the promoter-Pgrac212 was selected from a library of 80 promoters to construct pHT1200 (Pgrac212-amyQ) with the aim of investigating the enhancement of the α-amylase expression. The results showed that Pgrac212-amyQ secreted α-amylase more effectively than Pgrac-amyQ in B. subtilis 1012 and B. subtilis WB800N, an extracellular protease-deficient strain. This report demonstrates that Pgrac212 is a strong promoter that can be used to produce other secretional proteins in B. subtilis.

There are 6 species belonging to the genus Suillus Gray [Suillus granulatus (L. ex Fr.) Kuntze, S. luteus (L. ex Fr.) S. F. Gray, S. bovinus (L. ex Fr.) Kuntze, S. piperatus Bull. ex (Fr.) Kuntze, S. viscidus L. ex Fr. and S. grevillei (Klotzsch.) Sing.] in the West Highland of Vietnam. 5 species [Suilus granulatus (L. ex Fr.) Kuntze, S. luteus (L. ex Fr.) S. F. Gray, S. bovinus (L. ex Fr.) Kuntze, S. piperatus Bull. ex (Fr.) Kuntze, S. viscidus L. ex Fr.] grow on soil in the pine forest. Only the species Suillus grevillei (Klotzsch.) Sing. grows on soil in the pine forest and the mixed forest. The species S. grevillei (Klotzsch.) Sing. is a new species to the West Highland macrofungi flora and may be a new species to the Vietnam macrofungi. The fruit body fleshes of these 6 species are soft, easily rotten and they are used as food.

Elucidating the mode of action of antimicrobial peptides (AMPs) in cell membrane disruption is a topic of interest in understanding the efficiency of different AMPs, which is beneficial in designing antibiotics with desired potency and selectivity. As a key component of the innate immunity system, human cathelicidin LL-37 plays a crucial role in protecting human against infectious diseases. LL-37 kills cells by disrupting the membrane integrity through physical interaction with cell membranes. In this paper, we investigated the molecular interactions of LL-37 with various model cell membranes using Sum Frequency Generation (SFG), a modern vibrational spectroscopic technique. 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (POPG) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) supported bilayers were used as models for bacterial cell membranes and mammalian cell membranes, respectively. In our experiments, the helical LL-37 molecules associated with the POPG/POPG bilayer surface at a tilt angle of 50o from the bilayer normal, indicating a toroidal pore mechanism of action for the peptide at a concentration of 400 nM. On the contrary, no interactions were observed between LL-37 and a zwitterionic POPC bilayer at much higher peptide concentrations (∼1.2 μM). Cholesterol is shown to suppress peptide-induced disorder in the lipid bilayer membranes.  These results would explain a selective effect of LL-37 on bacteria over mammalian cells. Additionally, in order to deduce the orientation of LL-37 on model cell membranes, we have introduced a modified data analysis approach. Our findings demonstrate that SFG is a powerful technique which can provide insights into the molecular interactions between antimicrobial peptides possessing multiple helical segments and cell membranes. 

The mangrove forest along Lach Van river in Dien Chau distric, Nghe An province has dramatically decreased that resulted in biological diversity reduction and negative consequences for local people. Therefore to conduct research to survey and assess the biodiversity of this area for proper protection and recovery of this forest is important. In our study, field surveys and plot sampling were conducted for collecting data to assess plant species richness using Shannon diversity index and Simpson dominance index. Preliminary results revealed 16 species of 13 taxonomies in the mangrove along to Lach Van river. The structure of species composition is relatively poor, this is a typical character of mangrove ecosystem in central Vietnam region. Shannon diversity index (H'mean = 0.590) and Simpson dominance index (Dmean = 0.640) indicated relatively low biodiversity.