Makara Journal of Science
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Estimation of Raindrop Size Distribution Parameters Using Rain Attenuation Data from a Ku-Band Communications Satellite
No full textThe rain attenuation of down-link radio wave signals from the Superbird-C satellite and surface rainfall data have been used to estimate the parameters of exponential raindrop size distribution (DSD) at Koto Tabang (100.32 °E, 0.20 °S), West Sumatra, Indonesia. Prior to analyzing the measured data, the ability of the method to recover the parameters of known DSDs from which the samples were taken was examined. It was found that the method can accurately retrieve the input parameter of the sample. Only six case studies are presented here, so the results are representative rather than definitive. The method successfully estimated the DSD parameters of a stratiform case with steady intensity and deep convective rains of a short duration. This can be inferred from the small difference between the parameters derived from rain attenuation data and those derived from a 2D video disdrometer. The poor performance of the method was observed for a stratiform case with strong rain intensity fluctuation and shallow convective rains with very low rain top height. This phenomenon is probably due to the bias that may be inherent in the estimation of specific rain attenuation, such as the assumption of a constant path length throughout the rain
Antioxidant Constituents from the Bark of Aglaia eximia (Meliaceae)
No full textThe genus Aglaia is a a rich source of different compounds with interesting biological activities. A part of our continuing search for novel biologically active compounds from Indonesia Aglaia plants, the ethyl acetate extract of bark of Aglaia eximia showed significant antioxidant activity. Four antioxidant compounds, kaempferol (1), kaempferol-3-O-α-L-rhamnoside (2), kaempferol-3-O-β-D-glucoside (3) and kaempferol-3-O-β-D-glucosyl-(1→4)-α-L-rhamnoside (4) were isolated from the bark of Aglaia eximia (Meliaceae). The chemical structures of compounds 1-4 were identified on the basis of spectroscopic datas including UV, IR, NMR and MS along with by comparison with those spectra datas previously reported. All compounds showed DPPH radical-scavenging activity with IC50 values of 1.18, 6.34, 8.17, 10.63 mg/mL, respectively
Genetic Diversity of Japonica Rice (Oryza sativa L.) Based on Markers Corresponding to Starch Synthesizing Genes
No full textGenes related to starch synthesis and the metabolism contribute to a variety of physicochemical properties that determine the eating/cooking qualities of rice. Our previous study suggested that a set of molecular markers was able to estimate the eating quality of japonica rice. The present study reports the genetic diversity of 22 japonica rice varieties based on markers corresponding to starch synthesizing genes. The mean of the polymorphic information content (PIC: 0.135) value and the diversity index (0.171) indicated a low genetic diversity in these varieties. The phylogenetic tree clearly demonstrated three main clusters: 1) cluster I contained seven varieties with similar physicochemical properties; 2) cluster II only showed a Japanese variety, Koshihikari, and 3) cluster III included the most Korean varieties (14 varieties). This phylogenetic analysis did not completely represent the physicochemical properties differentiation of the japonica varieties, although it did reveal an initial clue to the close relationship between Korean rice and the Japanese and Chinese varieties. Notably, these markers were also able to identify a premium japonica rice. The molecular markers and information concerning the genetic relationship would be useful in improving the japonica rice along with its starch quality of in breeding program
Effect of Global Warming on Chlorophyll-a Concentration in the Indonesian Waters
No full textChlorophyll-a is a pigment that is contained in phytoplankton. Through the photosynthesis process, chlorophyll-a plays an important role in the global carbon cycle. The purpose of this research is to investigate the effect of global warming on chlorophyll-a concentration in Indonesian waters. The data used includes the monthly data of sea surface temperatures from 1984-2013, CO2 concentrations from 1980-2014, and chlorophyll-a concentrations from 2003-2014. The method used is linear regression. The results show that sea surface temperatures in Indonesian waters increased by about 0.51 °C from 1984-2013. The effects of global warming on chlorophyll-a concentrations varies between different areas of Indonesian waters. From the 12 research sites, 9 showed a decrease in concentration and 3 showed an increase
The Trophic Status of the Lubuk Lampam Floodplain in South Sumatera, Indonesia
No full textThe Lubuk Lampam floodplain’s ecosystem is naturally affected by the fluctuation of the water surface. This ecosystem also receives anthropogenic substances such as nutrients and other chemicals, especially from the oil palm plantation and its industrial processing activities. The main objective of this research was to determine the trophic status of the floodplain using the trophic level index (TLI) and Carlson’s trophic state index (TSI). The water quality and the fish samples were collected and analyzed from 7 stations representing various types of floodplain habitat. The results showed that the trophic status of Lubuk Lampam was hypereutrophic (very nutrient-rich). This was also supported by the high increase of the body weight (“b” value more than 3) and the high gonadosomatic index (GSI) of the studied fishes, i.e. Osteochilus vittatus 2.53-6.81% (male) and 3.00-15.86% (female); Helostoma temminckii 0.28-3.33% (male) and 1.30-10.43% (female); and Channa striata 0.33-0.59% (male) and 0.21-2.73% (female)
A New Benzoyl Compound Isolated from the Endophytic Fungi of Kandis Gajah (Garcinia griffithii) and Asam Kandis (Garcinia cowa)
No full textGarcinia griffithii and Garcinia cowa belong to the genus Garcinia. The genus Garcinia has been known to be a rich source of secondary metabolites, such as xanthones, benzophenones, flavonoids, steroids, terpenoids, and other phenolic derivatives. Previous investigations of endophytic fungi from G. griffithii revealed the presence of three compounds not found in the host. In order to the continue the phytochemical work on endophytic fungi of G. griffithii, the constituent of the endophytic fungi of G. griffithii was re-examined. In this study, a benzoyl compound similar to that found in the endophytic fungus of G. cowa was observed. The same benzoyl compound was also isolated from the endophytic fungus Acremonium sp of G. griffithii and Aspergillus sp of G. cowa with cultivation of eight weeks in static conditions at room temperature. The culture medium was partitioned using ethyl acetate and evaporated to obtain the concentrated extract. Isolation of compounds was performed using the chromatography method. The chemical structure was proposed on the basis of spectroscopic data, including ultraviolet (UV), infrared (IR), mass spectrometry (MS), proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), heteronuclear single-quantum correlation spectroscopy (HSQC), heteronuclear multiple-bond correlation spectroscopy (HMBC), and correlation spectroscopy (COSY)
The Molecular Diversity-based ISSR of Durio tanjungpurensis Originating from West Kalimantan, Indonesia
No full textThe Durian Tengkurak (Durio tanjungpurensis Navia) is one of the endangered exotic species in the Malvaceae family. The species is important for conservation of the germplasm and is considered a potential genetic resource for the development of durian in the future. The objective of this research project was to assess the molecular diversity of D. tanjungpurensis in West Kalimantan, based on Inter Simple Sequence Repeat (ISSR) markers. We applied ten ISSR primers to reveal the genetic diversity of 60 individuals from six natural endemic D. tanjungpurensis populations. The genetic diversity parameters were estimated based on binary data about PCR products (present or absent bands). The results showed that the mean number of observed alleles, the mean number of effective alleles, the genetic diversity, the Shannon’s Information Index score, the number of polymorphic loci, and the percentage of polymorphic loci were 1.53, 1.29, 0.17, 0.26, 77.83, and 52.59, respectively. An analysis of molecular variance (AMOVA) showed that the genetic diversity within a population (65%) was higher than that found between the populations (35%). UPGMA clustering and principal coordinate analysis, based on the DICE similarity matrix, were used to classify the populations into three groups: 1) Hutan Rejunak and Tembaga, 2) Bukit Merindang, and 3) Hutan Rawak, Bukit Sagu 1, and Bukit Sagu 2. Further analysis of the population structure using STRUCTURE software was used to classify all the individuals into two major categories, thus uniting Groups 2 and 3 as one major category. In conclusion, a high level of genetic diversity in the Durian Tengkurak was revealed utilizing the ISSR markers employed in the study
Transformation of Inhibitor of Meristem Activity (IMA) Gene into Jatropha curcas L.
No full textJatropha is one of the many biodiesel plants developed in tropical countries. Efforts to increase its productivity can be done using various methods of breeding. One of the breeding methods is the introduction of genes into the Jatropha plant. The aim of this study is to assess the success of genetic transformation using the Inhibitor of Meristem Activity (IMA) gene in Jatropha curcas. The research procedures included inoculation of explants with Agrobacterium tumefaciens, callus induction, screening test of selection media, regeneration, and gene expression analysis using Polymerase Chain Reaction (PCR). IMA is one of the genes that controls flowering genes and ovule development. It was first isolated from tomato plants and has been successfully overexpressed in these plants using the Cauliflower Mosaic Virus (CaMV) 35S promoter. In this experiment, plant transformation was performed on J. curcas as the target. Explant callus formation in both the control and treated samples was good, but shoot formation decreased dramatically in the treated explants. PCR analysis indicated that IMA genes can be inserted into J. curcas with the size of the IMA gene is 500 bp
The Use of TiO2-SiO2 in Photocatalytic Process to Degrade Toxic and Dangerous Waste
No full textThis study was conducted to investigate the use of TiO2 immobilized on SiO2 (TiO2-SiO2) in a photocatalytic process to degrade toxic industrial waste, phenol, linear alkylbenzene sulfonate (LAS), and Cr(VI), which is dangerous for humans and the environment. Titanium dioxide (TiO2), as a photocatalyst, can make the solution become turbid. Thus, TiO2-SiO2 was used to increase the possibility of ultraviolet (UV) transmission. The phenol and LAS levels were measured with the Indonesian National Standard (INS) while the Cr(VI) level was determined with the colorimetric method. The activity test for the catalyst in suspension and immobilization against phenol showed that TiO2-SiO2 was more active than TiO2. By using the photocatalytic process with the TiO2-SiO2 photocatalyst for 8 h, degradation of phenol and LAS reached 50% as a single compound and 12% as a mixture. However, TiO2-SiO2 did not decrease Cr(VI
Coupled Ocean-Atmosphere Mode in the Tropical Indian Ocean during 2011
No full textCoupled ocean-atmosphere mode in the tropical Indian Ocean, so-called the Indian Ocean Dipole (IOD), occurred during boreal summer to fall 2011. In this study, data from satellite observations and atmospheric reanalysis datasets together with data from ocean current mooring were used to evaluate the evolution of the 2011 IOD event. It is shown that the 2011 IOD was a weak and short-lived event. It developed in July, peaked in September, decayed in October and terminated in November. During the peak phase, maximum negative sea surface temperature anomaly off Sumatera-Java reached -1.2 °C. As oceanic response to easterly wind anomalies along the equator, the observed zonal currents in the central and eastern equatorial Indian Ocean also showed prominent westward currents during the peak phase of the 2011 IOD event.