Academia Journal of Biology

Helicobacter pylori is one of the most common infectious bacteria in the world that causes gastric diseases leading to cancer. The increase of multiple antibiotic resistance rates of H. pylori have been reported worldwide. Thus, development of novel drugs is urgently required. Piper betle has many therapeutic values in traditional medicine. In this study, therefore, we investigated antibacterial activity of P. betle extracts and their fractions against a H. pylori strain isolated in Vietnam. The agar disk diffusion assay showed inhibition zone of ethyl acetate extract and methanol extract from P. betle leaf that of were 46 mm and 32 mm in diameter, respectively. After fractionation of the ethyl acetate extract through silica gel column chromatography, two peaks, PD2 and PD3, out of 12 fractions showed the strongest antibacterial activity. PD2 was sub-fractionated further by re-chromatography on the silica gel column, and subfraction TK12 gave best resolution on LC-MS analysis. Finally, 4 potential compounds, quercetrin, calodenin B, vitexin and plicatipyrone, were identified in TK12 fraction. 

The genus Brulleia Szépligeti, 1904 was recorded for the first time in Vietnam, three new species, namely Brulleia flavosoma Long, sp. n.; B. mellicrus  Long, sp. n. and B. nigrisoma Long, sp. n., were descripbed and illustrated. A key to Brulleia species from Vietnam is provided. The checklist of the already known species of the genus Brulleia is also given.

Six species of the genus Toxabramis Gunther, 1873 (Cyprinidae, Cypriniformes) were found; among them two species were new for science. In the paper, the description of these new species is presented and a key to identify the known species of these genus is established. 1. Toxabramis maensis H. D. Nguyen & Q. N. Duong sp.nov. is found in the Ma river (Quanhoa and Thieuhoa districts, Thanhhoa province, Vietnam) Body elongate, strongly compressed. Head comparatively small. Mouth small. Oblique. Uper jaw prominent. Dorsal fin short, its origin behind that of ventral fin and near origin of caudal fin than top of rostral. Unbranched dorsal fin rays well ossified, denticulated behind. Anus immediatly in front of origin of anal fin. Lateral line complete. Coloration: body silvery; back dark. A dark axial lateral stripe running from the gill opening to the base of the caudal fin. Remarks: This species is near with Toxabramis hotayensis Hao, 2001, T. houdmeri Pellegrin, 1932 and T. nhatleensis sp.nov. but there are some different characteristics: the number of gill rakers on the first branchial arc of this species are more in comparison with other species of the genus; its number of lateral line scales are more in comparison with two species T. hotayensis and T. nhatleensis; its number of denticulate ossified unbranched dorsal fin rays are more in comparison with T. nhatleensis (table 1). 2. Toxabramis nhatleensis H. D. Nguyen, D. H. Tran & T. T. Ta sp.nov. is found in the Nhatle river (Lethuy district, Quangbinh province, Vietnam). Body elongate; Mouth small, comparatively oblique. Dorsal fin short, it’s origin behind that of ventral fin and its origin near of origin of caudal fin than top of the rostril. Unbranched dorsal fin rays well ossified, denticulated behind. Anus immediatly in front of origin of anal fin. Lateral line comlete. Coloration: body silvery; back dark. A dark axial lateral stripe running from the gill opening to the tip of the middle caudal fin rays. Remarks: this species is near with T. maensis H. D. Nguyen & Q. N. Duong sp.nov., T. houdmeri Pellegrin, 1932 and T. hotayensis Hao, but there are some different characteristics: the number of gill rakers of this species are more in comparison with T. hotayensis and its number of denticulate ossified unbranched dorsal fin rays are less than in T. hotayensis; its number of scales, gill rakers and denticulate ossified unbranched dorsal fin rays are less than in T. maensis (table 1).

A method for micropropagation was developed for Dendrocalamus asper, an economically and environmentally important bamboo. Disinfected seeds were cultured in flasks containing 20 ml of Murashige and Skoog’s medium (MS) supplemented with BA (1.0-7.0 mg l-1) or kinetin (1.0-7.0 mg l-1). Multiple shoots (6.53) were formed on MS medium supplemented with 3.0 mg l-1 BA and reached 1.49 cm in length. Continuous shoot proliferation was achieved on a MS medium supplemented with BA (1.0-7.0 mg l-1). The multiplication rate of 3.30 fold was achieved on MS medium supplemented with 3.0 mg l-1 BA. Propagules were excised from multiple shoots and transferred to rooting medium. After 4 weeks, high in vitro rooting was achieved on MS supplemented with 7.0 mg l-1 IBA. 3.70 cm in length root system developed 8.0-9.0 roots in 28 days. A high rate of plant survival (85%) was obtained within 2 weeks.

Miraculin is a taste-modifying and low calorie protein isolated from the red berries of Richadella dulcifica, a shrub native to West Africa. In this study, a synthetic miraculin gene was designed to optimize its codon usage for BY-2 tobacco cell lines. This gene was inserted into two constructs including pBI121/HSP-pro:Mir:HSP-ter that contains HSP promoter and HSP terminator isolated from Arabidopsis thaliana for enhancing production of miraculin and pBI121/35S-pro:Mir:NOS-ter for transformation into BY-2 tobacco cell lines. The presence and expression of miraculin gene in BY-2 tobacco cell lines were verified by PCR and Western blot, respectively. It was demonstrated that transgenic BY-2 tobacco cell lines grew stably in liquid media after 4-5 times of transplant. The expression of miraculin gene in transgenic BY-2 tobacco cell lines resulted in the accumulation of miraculin protein with molecular mass of approximately 43-45 kDa. Besides, it was observed that the expression of miraculin in HSP-pro:Mir:HSP-ter transformed BY-2 tobacco cell lines is better than the expression of miraculin in 35S-pro:Mir:HSP-ter transformed ones. For the first time, miraculin recombinant protein has been expressed in BY-2 tobacco cells providing a great potential for research and production of miraculin protein at industrial scale.

Macrobrachium chilinense sp. n.   Prawn of moderate size, body length 51-54 mm. Carapace glabrous, without microspinules. Rostrum narrow, straight overeaching Ant I peduncle, just reaching distal end scaphocerite. Rostrum formula: 3 + 7-8/3. Dorsal teeth unequally spaced, usually with wide gaps between 1-3 teeth on carapace. Second pereopods equal in size with body length, left and rigth similar in shape, all segments cylindrical form, covered with microspinules. Merus shorter than carpus (ratio 12/15), carpus scarcely equal in size with palm. Fingers very short, in comparision with palm, (0.3 times), distally armed with seta tuft, both moveable and immoveable fingers with 2 proximal teeth. First pleopod in male with endopod slightly concave at inner margin. Sexual dimorphism showed in smaller second pereopods in female. Eggs dimension d = 1-1.2 mm. Dimensions (male): (mm) tl; 51-54; cl: 15; M; 11-12: C: 14-16; D = 5-6.

Saccharomyces cerevisiae represents a valuable food supplement providing proteins and vitamins to the human diet. This yeast is also employed in studies on the interaction between microelements and microorganisms because it is easy to cultivate with a high cellular biomass yield in a short period of time. The present study was undertaken to investigate the influence of the medium composition (zinc, carbon and nitrogen concentrations) on zinc accumulation in S. cerevisiae. Results showed a positive correlation between zinc sulphate supplementation in the medium and the amount of zinc accumulated in the biomass. Zinc-rich (15 mg/g) yeast production was optimized using the software JMP. The optimal fermentation parameters were as follows: zinc sulphate content of 1.5 g/l, glucose concentration of 100 g/l, and yeast extract concentration of 5 g/l. 

Having surface activity, emulsifiers, foaming agents,  biosurfactants are widely used in many industries such as agriculture, chemistry, cosmetics, pharmaceutics, espencially in petroleum industry. Selecting marine biosurfactant-producing microoganisms and studying properties of biosurfactants are necessary to applying in oil pollution treatment. From marine sand samples taken from Vietnam coastal zone, a strain of biosurfactant-producing H3 was isolated. Strain H3 was identified as Acinetobacter calcoaceticus (id 99.9%) according to its morphological and 16S rDNA sequences. It grew and produced biosurfactant the most in medium with temperature 30oC, pH7, 0-1% NaCl (w/v) and DO as carbon source. In this condition, strain H3 produced crude biosurfactant of 15.73 g/l with the emulsification index E24 of 80%. Base on GC-MS analyses, the biosurfactant produced by Strain H3 consist of hydrophobic (-CH3) and hydrophilic (-COOH) groups in chemical structure C16H22O4 (1,2 benzendicarboxylic acide, bis 2- metyl propyl ester).

The Tonkin Snub-nosed Monkey Rhinopithecus avunculus is among the World’s 25 most endangered primates. At present, the species is found only in few forest areas in Ha Giang and Tuyen Quang Provinces, north-east Vietnam with a total number not exceeding 250 individuals.  The forest block in Cao Ma Po, Ta Van and Tung Vai Communes of Quan Ba District, Ha Giang Province (the Cao - Ta - Tung forest) harbors the second largest population of Tonkin Snub-nosed Monkey. This population was estimated to be conisted of about 30–35 individuals in 2007.  However, it faces a number of serious threats (wildlife hunting, habitat degradation by widespread forest farming of Tsao-ko cardamom plant, etc.) that may lead the population to be extinct in near future. The population was reduced to 15–21 individuals in 2016 due to these threats. In 2017–2018, we conducted a study to identify a priority habitat area to establish the Quan Ba Tonkin Snub-nosed Monkey Conservation Area. The results of our study show that the distribution of  the Quan Ba Tonkin Snub-nosed Monkey  population is  confined to a small area (about 5,000 ha) belonging to the Theng Chu Phin, Dao Dan Chai, Ta Lay mountains, the Hill 754 and a forest patch along the Vietnam-China  border  from the Post 283  to Post 295. This area harbors the best forest of the Cao - Ta - Tung area. The forest covers 92.3% of the area, and only 7.7% of the area is a non-forest land. There are two types of forest: evergreen broad-leaved forest (50.0% of total area) and limestone evergreen broad-leaved forest (42.3%).  The evergreen broad-leaved forest has been degraded to medium and restoration status. Tsao-ko cardamom Amomum tsao-ko fields are widespread. The limestone evergreen broad-leaved forest of almost primary status remains in very steep slopes and limestone mountains. The Cao - Ta - Tung forest was designated as a watershed protection forest that allows farming of agricultural and medicinal plants inside the forest and the forest farming of Tsao-ko cardamom is widespread becoming the most serious threat to the long-term survival of the Tonkin Snub-nosed Monkey population. In order to ensure long-term survival of the Quan Ba Tonkin Snub-nosed Monkey population, the  area of the Theng Chu Pin, Dao Dai Chai, Ta Lay, Tung Lau mountains,  the Hill 754 and a forest patch along the Vietnam-China border from the Post 283 to Post 285 must be designated as a special-use forest, i.e. to establish a Quan Ba Tonkin Snub-nosed Monkey Conservation Area.