International Letters of Natural Sciences Vol. 80

Abstract: Selected persistent organochlorine pollutants, including DDT and its metabolites, hexachlorobenzene, dieldrin, Aldrin, heptachlor, HCH as well as some of their isomers were determined in water, sediment and fish samples from the Ethiope River in Southern Nigeria. Twenty organochlorine pesticides were detected in both seasons from October 2012 – September 2013. Results revealed ∑HCH to be 0.620µg/L (water), 33 ng/g (sediment) and 29.00 ng/g (fish) for the rainy season while concentrations of 0.170 µg/L (water), 14 ng/g (sediment) and 28.00 ng/g (fish) were obtained for the dry season. 0.05–0.15 ng/g for aldrin, 0.12–5.8 ng/g for dieldrin, 0.22–0.64 ng/g for endrin, 0.24–6.37 ng/g for endosulfan and 0.21–8.81 ng/g for ΣDDT (p, p` -DDD, p, p` -DDE, p, p` -DDT). Among the OCPs, ∑HCH, endosulfan and PDDT were the most dominant compounds in the river sediments. γ- HCH was the most frequent detected compound in all the samples from this river. Among the cyclodiene compounds, aldrin was in abundance in most of the sediments, water and fish samples. γ-HCH, γ-HCH and HCB contributed this highest value for the water, sediment and fish sample respectively in the rainy season while aldrin, endrin and HCB were the highest contributors to the ΣOCPs to the mean of water, sediment and fish respectively. Hazard quotient and bioaccumulation analysis carried out on the fish sample revealed that the fishes were heavily contaminated with values >1 for both seasons which possess a possibility for ecological concern.

Abstract: The objective of this study was to evaluate genetic diversity of 35 Huperzia samples collected from the different ecological areas in Vietnam by using rbcL markers. The results revealed that the samples were genetically diverse in high genetic similarity which ranged from 98.0 to 99.0%, respectively. Based on the Genbank data in comparison, it was ascertained that only one sample (BK3) is a member of H.phlegmarioides group, and others belonged H. squarrosa group as divided into two main groups by phylogenetic tree analyses. It suggests that some Huperzia samples may plausibly descend from the same origin, evolution and arising relations. This study has provided useful information for further identifying the high-quality genetic plant sources for propagation, development and conservation of the high-valued medicinal materials of Huperzia plants in this country.

Abstract: Optimum usage of fertilizers is an important factor that defines the fate of crop yield by confirming the accessibility of nutrients in soil. Imbalance use of fertilizer not only reduces the crop productivity but also adversely affects the soil properties. A one-year experiment was carried out to explore the impact of different levels of farm yard manure and urea on soil properties, growth and yield of wheat crop. Treatments were application of nitrogen at i) 125 kg ha^-1 from urea, ii) 80 kg ha^-1 of nitrogen from urea + 10 tons of farm yard manure ha^-1 and iii) 20 tons of farm yard manure ha^-1. Wheat cultivar Sehar-2006 was used in the experiment. All the treatments’ combination affected crop growth, economic yield and soil properties. However, maximum positive impact of combined use of farm yard manure and urea was observed. Results indicated that productive tillers per unit area (16%), plant height, number of spikelets per spike (12.5%) and economical yield (11%) were greatly enhanced by combined usage of urea and farm yard manure as compared to sole application of urea. Combined application of urea and farm yard manure also positively affected the soil bulk density, particle density, percent porosity and soil saturated hydraulic conductivity as compared to either sole use of urea or farm yard manure. Combined usage of farm yard manure and urea are suggested better to produce higher economical yield along with improved soil properties.

Abstract: Hypseleotris agilis locally known as Bugwan is a native species and one of the most abundant fishes of commercial value in Lake Mainit, Philippines. A total of 1,584 H. agilis from Lake Mainit near the mouth of Kalinawan and Puyo River were caught from May 2018 to February 2019 to determine the length-weight relationship (LWR), condition factor (K), gonadosomatic index (GSI) and hepatosomatic index (HSI) of this species. Positive allometric growth was observed for both sexes (b>3). Sex ratio indicated the dominance of males over females as much as 58.7%. The number of ripe males and gravid females was observed throughout the months of the collection, which indicates the ability of the fish species to spawn continuously throughout the year. Determination of GSI in both sexes showed higher values during November (males) and December (females). However, HSI values were relatively low during the spawning season, which would indicate the usage of energy for gonadal maturation. The K factor showed high values during the peak spawning months, directly proportional to GSI values. This study provides updated information for management and conservation of this important fishery resource in Lake Mainit.

Abstract: Size-structure analyses and gonad characteristics of the elongate sunset clam Gari elongata from the coastal waters of Hinatuan, Surigao del Sur, Philippines, was determined in this study. An opportunistic sampling approach was applied during the collection of G. elongata from the coastal waters of Brgy. Loyola and Brgy. Aquino. A total of 1437 G. elongata individuals were subjected to length-weight measurements, and gonads from five (5) individuals per sex among size classes were processed for histological characterization. The maximum total length of G. elongata recorded is 5.42 cm, way smaller than its congeners elsewhere, which is at 7.0-9.2 cm. The size-structure analysis shows that G. elongata from Brgy. Loyola exhibited negative allometric growth while those gleaned from Brgy. Aquino exhibited positive allometry indicating variation in growth dynamics. Known as a gleaning source, Barangay Loyola is abundant in G. elongata, but individuals are much smaller compared to those gathered from Barangay Aquino. A ratio of 1:1 for male and female classification was observed, as seen from gonad histological analyses. Ovaries were found in the spawning capable state with gonads in ripe (30%), spent (25%), early development (25%), and partially spawning (20%) stages. Testes were found to be in the ripe (40%), early developing (10%), spent (10%), and partially spawning (40%) stages. Gari elongata exhibits spawning capable gonads at 2.85 cm and 2.95 cm for males and females, respectively, which suggests that the shellfish has adapted early to reproduction to maintain its population in the coastal waters of Hinatuan. The small body lengths of individuals with mature gonads indicate that G. elongata may have been exposed to some stress in their natural environment. Regulated management of G. elongata to avoid over-harvesting and assessment of water and sediment quality of their natural habitat is highly recommended

Abstract: (2E,6E)-3,7,11-Trimethyldodeca-2,6,10-trien-1-ol or farnesol is a natural isoprenoid possessing a range of beneficial biological activities as anti-candidiasis, anti-tumor and anti-hyperglycaemia. The present study, for the first time, isolated and identified farnesol from Euclea crispa leaves’ extract, subsequently, validated its antioxidant and antimicrobial potentials. The isolated compound was confirmed by spectroscopic techniques including ultraviolet-visible (UV/Vis), fourier-transform infrared (FTIR), and ¹H and ¹³C magnetic resonance (NMR) spectroscopies. By in vitro investigations, farnesol exhibited a considerable antioxidant activity with IC₅₀ values of 113.79, 109.59, and 116.65 µg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and nitric oxide radical scavenging assays, respectively. Additionally, farnesol performed a potent reducing power capacity which was in line with ascorbic acid, an outstanding antioxidant. By the disc-diffusion assay, farnesol exposed the superior antimicrobial activity against various disease-causing microorganisms. Significantly, at the concentration of 50 µg/mL, the compound effectively inhibited the growth of Escherichia coli and Aspergillus niger with inhibition zones of 12 and 11 mm, respectively. Findings from this research suggest that E. crispa leaf is a potential source of farnesol, a powerful antioxidant and antimicrobial agent.