Valentina BULIMAGA, Liliana ZOSIM, Alina TROFIM, Maria PISOVA
Abstract The dynamics of accumulation of total and acidic (sulfated) exopolysaccharides (EPS) produced by cyanobacteria Spirulina platensis and Nostoc linckia under the action of some chemical regulators at the two steps cultivation with the increasing of light at the second step were established. Procedures of EPS isolation from cyanobacteria Spirulina platensis and Nostoc linckia and the scheme of EPS production, obtaining and quantification have been developed. The synthesis of sulfated exopolysaccharides (till 91 mg/l) at the cultivation of spirulina in two stages was positively influenced by the variation of the light regime and the addition of carbon source with or without addition of Na2SeO3. Supplementing of the nutrient medium with sodium selenite (2 mg/l) and varying of light to 2500 lx in the 7th day of cultivation of cyanobacteria Nostoc linckia led to a maximum increasing in the amount of total and acidic exopolysaccharides (477 and 422 mg/g, respectively).
Keywords: Cyanobacteria cultivation; Spirulina platensis; Nostoc linckia; acidic exopolysaccharides; procedures of obtaning.
Valeriu-Ioan VINŢAN
Abstract. In the current paper we are presenting a phytosociological study of the spruce forests identified in the upper part of the Orăştie river basin situated in the central-western part of Romania, which belong to the association Hieracio transsilvanici-Piceetum and the subassociation calamagrostietosum villosae. The characterization of the subassociation under analysis and the presentation of its synthetic table have been done by selecting the most representative releves carried out in the spruce forests on the upper course of the river Orăștie. The phytocoenoses of the subassociation were analyzed in terms of physiognomy and floristic composition, life forms, floristic elements and ecological indices. The subassociation's phytocoenoses, which colonize the steep mountain slopes in the high boreal floor, fulfill hydrological, climatic and soil protection functions as well. We also notice the presence of Romanian Carpathian endemites (Silene nutans subsp. dubia) and Tertiary relicts (Sanicula europaea).
Keywords: phytocoenosis; association; relevee; floristic elements; life forms; ecological indices; Picea abies.
Cristina STANCĂ-MOISE, Tom BRERETON, Robert BLAJ
Abstract. This paper is part of a larger study started in 2011 for monitoring and control the populations of Lymantria monacha L., 1758 using pheromone traps. The continuation of the pest population monitoring in 2017 had the purpose of drawing up a plan to improve the control and limitation methods for 2018, as well as the detection of the outbreaks of this pest in the forest perimeter of the Miercurea Sibiu Forest District in Romania.
Keywords: pheromonal traps; Lymantria monacha L.; 1758; Forest District Miercurea Sibiului (Sibiu county, Romania)
Amel CHOUIA, Atef CHOUIKH, Fatma ALIA, El Hadda ADJAL, Azzedine CHEFROUR, Yasmina AIT KAKI
Abstract. The aims of this study were to evaluate the DPPH• radical scavenging and antibacterial activity of different metabolites extracted from two plants: essential oil from Matricaria recutita L. and flavonoids from flowers and leaves of Hibiscus rosa-sinensis L. The essential oil extracted by steam distillation method have presented a yield of 0.55%, with a blue color, as for the flowers extract of H. rosa-sinensis is the richest in flavonoids (FFR: 3.19%). Flavonoid extracts from Hibiscus rosa-sinensis L. flowers provided the highest antioxidant activity against free radical inhibition of DPPH. The essential oil of Matricaria recutita tested on pathogenic germs revealed a presence of positive effects on all the bacterial strains used. While Hibiscus rosa-sinensis leaf and flower extracts inhibited only the growth of certain pathogens such as Serratia rubidae and Enterobacter sp. The results obtained in this study and the comparison with other works in the same field, allowed us to unveil the importance attributed by traditional medicine to Matricaria recutita L. and Hibiscus rosa-sinensis L. as source of natural antiseptics.
Keywords: Matricaria recutita; essential oil; flavonoids; Hibiscus rosa-sinensis; antioxidant activity; antibacterial activity.
Nikhil MEHTA, Priyanka RAO, Raman SAINI
Abstract. In the recent times, the trend has been towards the use of natural and safe drugs with less or no side effects and equally effective like synthetic drugs for curing diseases. It leads the research towards finding new drugs from natural sources of which plants seems to be good candidate. So, in this view the present research has been done to investigate the presence of different phytochemicals such as phenols, terpenoids, saponins, tannins, etc. and antibacterial property of Sesbania aculeata against different bacteria. The plant is mainly cultivated for soil enrichment, various medicinal purposes, fibre, fuel wood, fodder, paper and dye industry and other agro-forestry use though up to yet not reported in details for its extract’s thermostability and antimicrobial property. Methanolic extracts were prepared from different parts of the plant at 65ºC for 10 cycles using Soxhlet apparatus. All the extracts analysed at their natural pH have been found to show antibacterial activity and among them prepared from seeds coat shows best results with average zone of inhibition varies from 26-32 mm in diameter at concentration of 10 mg/ml, by optimising biophysical parameters. The minimum inhibitory concentration of all the extracts ranges from 1-4 mg/ml against different bacterial strains which shows that the extracts even act at low doses. Extracts checked for thermostability at the range of temperature (60- 100ºC) and found stable up to 90ºC with no effects on antimicrobial activity. Among the different strains tested, Gram negative bacteria show higher susceptibility as compare to Gram positive bacteria. The results have shown that the extracts could be the good source of new medicines that may be used to treat various bacterial infections.
Keywords: Sesbania aculeata; phytochemicals; plant extract; antibacterial.