Abscisic acid-enhanced starch accumulation of bioenergy crop duckweed (Spirodela polyrrhiza)

This study demonstrates that abscisic acid (ABA) induced enhanced starch accumulation in duckweed Spirodela polyrrhiza. ABA up-regulates the expression of the APL2 gene which enhances the AGPase activity and results in larger and more starch granules in the duckweed fronds.

COMPARATIVE STUDY OF THE ANTIBACTERIAL ACTIVITY OF SEAWEED (Sargassum muticm) AND FRESHWATER WEED (Spirodela polyrrhiza)

Development of new drugs is needed to resist the situation of diseases caused by drug resistant bacteria for public health safety. Natural resource is a big source to find candidates having antibacterial activity and aquatic weed is such a natural resource possessing such activity. The current study was aimed to determine the effectiveness of sea weed (Sargassum muticum) and fresh water weed/duckweed (Spirodela polyrrhiza) against six bacterial isolates Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Pseudomonas luteola and Bacillus subtilis. The potency of methanol and ethanol extracts of these weeds was compared to determine the best candidate of weeds in inhibiting bacteria. Both agar well diffusion method and micro dilution was done to observe the antibacterial activity. Ethanol extract of Sargassum muticum worked best against Pseudomans aeruginosa (30mm zone of inhibition) and no activity against Bacillus subtilis. Methanol extract of the same Sargassum muticum showed less activity compared to ethanol extract except for Bacillus subtilis where it showed 21mm zone of inhibition. Ethanol and methanol extracts of Spirodela polyrrhiza showed less antibacterial activity against the bacteria compared to Sargassum muticum. They showed no antibacterial activity against Klebsiella pneumonia and Staphylococcus aureus. On average, the extracts impart a significant antibacterial activity against these six bacteria which are resistant to several antibiotics. Even one of them (Escherichia coli) is resistant to 4th generation cephalosporin but still fairly susceptible for extracts. The antibacterial properties of these marine and freshwater weeds can be subjected to develop new therapeutics to inhibit the resistant bacteria.

Antimicrobial Efficacy and Phytochemical Analysis of Three Aquatic Plant Species in Bangladesh

Aquatic plants are generally considered as breeding grounds for mosquitoes and other harmful vectors of diseases. However, in recent years, some research has been carried out to test their significance as sources of antimicrobial lead molecules. The aim of this research was to study the phytochemical composition of local aquatic plant species and test their antimicrobial effect against selected bacterial strains. Three different aquatic plant samples were collected from a large water body near Dhaka. Ethanol and ethyl acetate extracts of the plant species: Eichhornia crassipes, Pistia stratiotes, and Spirodela polyrrhiza were tested against Staphylococcus aureus, Salmonella typhi, and Lactobacillus spp. Out of the eight different extracts, only the ethyl acetate extracts prepared from Eichhornia crassipes showed significant anti-microbial activity against Staphylococcus aureus and Salmonella typhi. In disk diffusion tests, zone of inhibitions of ethyl acetate extracts of Eichhornia crassipes leaves and stems were 8.00 ± 0.5 mm and 7.83 ± .29 mm respectively. In well diffusion tests, zone of inhibitions of ethyl acetate extracts of Eichhornia crassipes leaves and stems were 18.00 mm and 20.00 mm respectively. Zones of inhibition of ethyl acetate extracts of Eichhornia crassipes stems against Staphylococcus aureus were 7.67 ± 0.29 mm and 12.00 mm respectively in disk and well diffusion tests. Zone of inhibition of ethyl acetate extracts of Spirodela polyrrhiza was 8.17 ± 0.29 mm against Staphylococcus aureus in disk diffusion tests. No extracts showed any antimicrobial potential against Lactobacillus. Phytochemical composition analysis showed the presence of alkaloids, flavonoids, steroids, phenolics, tannins, glycosides, and cardiac glycosides in the different ethanol and ethyl acetate extracts. Tannins were absent in all extracts and saponins were absent in all ethyl acetate extracts. Bangladesh J Microbiol, Volume 35 Number 1 June 2018, pp 7-11

Ростові ознаки Potamogeton natans L. у різних еколого-ценотичних умовах водойм басейну Десни

З опорою на величини восьми динамічних метричних морфопараметрів та п’яти динамічних алометричних надано інформацію про швидкість росту раметів Potamogeton natans L. у водоймах басейну річки Десни. Оцінено вплив на ріст Potamogeton natans низки екологічних чинників (проективного покриття, товщі води, її прозорості, характеру донних відкладів). Показано, що в регіоні досліджень у рослин цього виду найбільші значення більшості динамічних морфопараметрів припадають на ценопопуляції з угруповань Potamogeton natans subpurum (р. Свига) та Potamogeton natans subpurum варіант зі Spirodela polyrrhiza і Lemna trisulca, а найменші – на Potamogeton natans subpurum (із заплавного озера).