The diversity and load of heterotrophic bacteria and fungi associated with the mangrove soil from Suva, Fiji Islands, was determined by using the plate count method. The ability of the bacterial isolates to produce various hydrolytic enzymes such as amylase, gelatinase and lipase were determined using the plate assay. The heterotrophic bacterial load was considerably higher than the fungal load. There was a predominance of the gram positive genus, Bacillus. Other genera encountered included Staphylococcus, Micrococcus, Listeria and Vibrio. Their effectiveness on the degradation of commercial polythene carry bags made of high density polyethylene (HDPE) and low density polyethylene (LDPE) was studied over a period of eight weeks in the laboratory. Biodegradation was measured in terms of mean weight loss, which was nearly 5 % after a period of eight weeks. There was a significant increase in the bacterial load of the soil attached to class 2 (HDPE) polythene. After eight weeks of submergence in mangrove soil, soil attached to class 1 and class 3 polythene mostly had Bacillus (Staphylococcus predominated in class 2 polythene). While most of the isolates were capable of producing hydrolytic enzymes such as amylase and gelatinase, lipolytic activity was low. Class 2 HDPE suffered the greatest biodegradation. Rev. Biol. Trop. 55 (3-4): 777-786. Epub 2007 December, 28.
Forty samples of freshwater clam (Batissa violacea), popularly known as Kai, collected from the Suva market were analysed for total aerobic plate count and total coliforms. The heterotrophic bacteria isolated by plate count were also characterised up to genera. The results indicated higher than acceptable level of plate count and coliform bacteria. While total plate count of aerobic heterotrophic bacteria ranged from 5.5 x 105 colony forming units (cfu) per gram to more than 107 cfu/ gram, total coliform load varied between 1.1 x 104 to 1.1 x 105 per 100 gm of Kai flesh. The characterisation of the heterotrophic bacteria revealed the predominance of the genera Micrococcus (34%) and Bacillus (24%). Other genera encountered included Acinetobacter, Vibrio, Aeromonas, Alcaligenes, Pseudomonas, Streptococcus and members of the family Enterobacteriaceae. The results revealed the need for depuration of the Kai in clean running water to reduce the bacterial load to acceptable levels. Temperature control soon after harvesting by proper icing and thorough cooking of the Kai before consumption is also recommended.
There has been a growing interest in medicinal plants by the locals of the Pacific Islands since it is readily available. Annona muricata, commonly called soursop is one of such plants which is popular because it is being used to treat initial stages of cancer due to its antioxidant properties. This study investigated various extraction methods which could be used to compare and see the effectiveness of each on the chromosomes. The cytotoxicity and genotoxicity effect were studied using Allium cepa root tip cells. Eight onion bulbs were subjected to the treatment groups which were made using methanol, water and hexane extracts of A. muricata. Three different concentrations from each extraction solvent were used. The A. cepa root tip cells were subjected for 24 h to three different leaf extractions after left to grow in water. Concentrations of 12.5, 25 and 50 g/L were used. After the treatment, onion bulbs were put back in water to recover. Hence, 5 root tips from each bulb were removed (before treatment, treatment and recovery) with cells undergoing mitosis counted under 400x of a compound microscope. All studied concentrations of A. muricata methanol extract showed significant (p≤0.05) drop in the mean mitotic index when compared with control (mean MI reduced by 9.9, 44.4 and 54.2% for 12.5, 25 and 50 g/L respectively). A. muricata water extract also showed significant differences at 12.5 g/L where mitotic index (MI) was reduced by 8.6%. At 25 g/L, the reduction was by 35.3% and by 42.8% at 50 g/L. Drastic effect (p≤0.05) was observed with the soursop-hexane extract that reduced the MI significantly in 12.5 g/L by 5.0% and by 29.7% at 25 g/L. A huge reduction in MI was observed at 50 g/L where MI declined by 72.8%. Chromosomal aberrations were also observed which indicates the genotoxicity of the extracts. All the extraction methods contributed significantly towards the drop in total MI. Compounds in the extracts is mitodepressive.
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