Makara Journal of Science
Not a member yet
423 research outputs found
Sort by
Role of Indigenous Nitrogen-fixing Bacteria in Promoting Plant Growth on Post Tin Mining Soil
No full textPost tin mining soil is generally marginal with low pH, has poor nutrient content, and is thus unfavorable for plant growth, particularly for Sorghum bicolor, which is a nutrient-demanding plant. Indigenous bacteria are usually used in bioaugmentation to ameliorate environmental degradation due to their ability to adapt well. This research aimed to isolate indigenous nitrogen-fixing bacteria and evaluate its potential for promoting the growth of S. bicolor on post tin mining soil. Nitrogen-fixing bacteria were isolated from post tin mining soil by using specific media and identified by Bergey’s manual. Twenty five isolates were obtained, and eight of them (Azospirillum sp., Azospirillum lipoferum, Azotobacter chroococcum, A. paspalii, and Rhizobium sp.) were identified as nitrogen-fixing bacteria. A greenhouse experiment was conducted using factorial completely randomized design with three replications. The first factors were fertilizers, i.e., NPK; A. lipoferum CBT4 + NPK; A. lipoferum CBT4; and without fertilizer (control). The second factors were soil types, i.e., A (fertile soil from Cibinong), B (soil from Bangka Botanical Garden), C (soil from post tin mines two years after mining), and D (soil from active tin mining). Result showed that Azospirillum lipoferum CBT4 isolated from C (soil from post tin mines two years after mining) exhibited the highest IAA, Ca-P solubilizing ability, and PME-ase activity. This species survived up to a population of 107 CFU/gram soil in the three types of post tin mining soils and could be a potential plant-growth promoting rhizobacteria (PGPR) species for effectively improving the growth of S. bicolor plant on post tin-mining soil
Extraction of “Quercetin-Rich” Red Onion Skin with Acetone and Chemical Modification using Aromatic Diazonium Salts
No full textThe extraction of “quercetin-rich” red onion skin (red onion skin extract [ROSE]) using acetone and chemical modification with aromatic diazonium salts of aniline (AmROSE), 2-aminophenol (APmROSE), and 2-aminobenzoic acid (ABmROSE) were carried out in this study. The effects of the particle diameter of red onion skin (ROS), volume of the solvent, and percentage of acetone in the solvent mixture on the extraction yield were investigated. The solubility, color, melting point, and functional groups present in ROSE before and after modification were also analyzed. The extraction of ROS using an aqueous solvent of 50% acetone gave the highest percentage extraction yield. In addition to the C=O, OH, C-O-C, and C-O-H functional groups that were present in both unmodified ROSE (UROSE) and modified ROSE, Infrared spectra results revealed that all the modifications (AmROSE, APmROSE, and ABmROSE) showed the presence of N=N and C-N of aromatic azo compounds at 1512–1496 and 1288–1256 cm−1, respectively. The three modifications were also found to be more soluble than UROSE in all the solvents. The melting point of UROSE and its modifications was within the range of 78 °C–105 °C, which was lower than that of commercial quercetin dehydrate P-Q (300 °C–310 °C)
Potential of Indigenous Methanotrophic Bacteria as a Biological Control Agent Against Xanthomonas oryzae pv. oryzae Causing Diseases on Rice
No full textMethanotrophic bacteria inhabit the rhizosphere and potentially inhibit the growth of pathogens. Therefore, they have potential utility as biological control agents. This study aimed to analyze 10 isolates of indigenous Methanotrophic bacteria with the potential to act as biological control agents for Xanthomonas oryzae pv. oryzae. Analysis of antagonistic activity was conducted by the direct inhibition method on media using the following parameters: the time to formation of a clear zone, the diameter of the clear zone, and the index of inhibition. The study recommended two isolates as biological control agents that can be combined to inhibit the growth of Xanthomonas oryzae pv. oryzae
Sequence Variability in the NRAMP1 Gene among Indigenous and Exotic Chicken Types
No full textThe natural resistance-associated macrophage protein 1 (NRAMP1) gene in chickens, which exists on chromosome 7, is thought to play a significant role in disease resistance. Variations in this gene have been documented and have played crucial roles in the variations in the resistance and/or susceptibility that is expressed by individuals and different groups of animal species. In this study, the NRAMP1 gene was studied for single nucleotide polymorphism (SNP) variability between indigenous and exotic chicken breeds. The gene was amplified using the polymerase chain reaction (PCR) method and sequenced and analyzed. Six SNPs, both synonymous and non-synonymous (C3700T, G3702C, A3712C, C3714G, C3693G, and G3705T), were detected in the gene in both indigenous and exotic chicken types. One allele form was detected among all the sample animals that were studied. A phylogenetic tree revealed that the indigenous chicken type and the exotic broiler chicken type are genetically similar with respect to this gene. However, the exotic layer chicken type is genetically suggested to be distantly related to both the indigenous and broiler chicken types, indicating that the gene has probably been evolving both within and among different poultry species
Determining Soft Layer Thickness Using Ambient Seismic Noise Record Analysis in Kota Baru, South Lampung
No full textThe local site effect of an earthquake can be calculated through an analysis of short period ambient noise, known as microtremors. The fundamental frequency and amplification factors can be identified by analyzing microtremors using the Horizontal to Vertical Spectral Ratio (HVSR) method. This information can then be used to determine the thickness of the soft layers of sediment. This study analyzed microtremor recordings made in Kota Baru, South Lampung. The amplification factor range according to the HVSR method was 2.3 to 6.17, and the fundamental frequency range was 0.56 Hz to 1.46 Hz. Some spectrums exhibit two peaks with f0 > f1. We suggest that these locations have two layers with significant impedance contrast, which aligns with the geological conditions. The center of the Kota Baru area, especially the region around T11 and T15, has a thicker soft layer than the outskirts; in the central area, the soft layer is approximately 85 to 102 meters thick. The western part of the analyzed area has a shallower soft layer of about 32 to 46 meters. The analysis indicates that the western part has less amplification because it is shallower than the other parts of the analyzed region
Decolorization of Synthetic Dyes by Ligninolytic Enzymes from Trametes hirsuta D7
No full textThe ability of ligninolytic enzymes from Trametes hirsuta D7 to decolorize several synthetic dyes was investigated. A crude enzyme powder was produced by fermenting oil palm empty fruit bunch fibers for one month. The dye decolorization by the enzymes occurred at an efficient 0.25 U/mL. The enzymes degraded 100, 200, 300, 400, and 500 ppm Remazol Brilliant Blue R (RBBR) within 7 h by 95.57 ± 0.32%, 93.46 ± 3.09%, 91.84 ± 0.65%, 86.44 ± 0.97%, and 82.14 ± 0.52%, respectively. The enzyme also decolorized anthraquinone (Acid Blue 129), monoazo (Acid Orange 7), diazo (Reactive Black 5), and trimethyl methane (Methyl Violet) dyes within 7 h by 94.59 ± 7.97%, 13.99 ± 0.30%, 7.61 ± 0.01%, and 7.59 ± 0.18%, respectively. Addition of MnSO4, H2O2, and violuric acid enhanced the dye decolorization rate by up to 10-fold. This study shows the potential for application of ligninolytic enzymes from T. hirsuta D7 in the treatment of wastewater effluent of textile industries
Eco-friendly and Convenient Synthesis of Biologically Active Polysubstituted Dihydro-2-Oxypyrroles Using Manganese (II) Nitrate Tetrahydrate at Ambient Temperatures
No full textA convenient, expedient and efficient method for the synthesis of polysubstituted dihydro-2-oxypyrroles is described via the one-pot four-condensation of dialkyl acetylenedicarboxylate, formaldehyde, and amines (aromatic and aliphatic) at ambient temperature in the presence of Manganese (II) Nitrate Tetrahydrate (Mn(NO3)2.4H2O) as a cost effective and inexpensive catalyst. The present methodology provides a simple and eco-safe procedure for the synthesis of polysubstituted dihydro-2-oxypyrroles with some additional advantages, such as good to high yields, short reaction times, avoidance of hazardous or toxic catalysts, simplicity of operating and work-up procedures with no necessity for chromatographic purification steps
Effect of Backbone, Sequence, and Positional Disorders on Electrical Transport in Modified Poly(dA)–Poly(dT) DNA Wire
No full textThe effect of medium and thermal fluctuations on charge transport in two types of modified poly(dA)–poly(dT) DNA was studied by calculating the transmission probability and current–voltage (I–V) characteristics of a model DNA wire sandwiched between two metal electrodes. Modification was performed by randomly replacing several A–T base pairs with C–G or G–C base pairs along the DNA chain. The medium–DNA interaction was modeled as the backbone onsite energy disorder in the DNA tight-binding Hamiltonian. The helicity of the molecule was considered by incorporating twist-angle-dependent intrastrand hopping amplitude in the model. Thermal fluctuation was modeled by varying the twist angles of each base in the DNA wire. Twist-angle disorder was influenced by temperature and frequency. The I–V results obtained by modeling the backbone disorder effect showed that the current decreased and the threshold voltage generally increased as disorder strength increased to a critical value. The current increased and the threshold voltage decreased as the disorder strength exceeded this critical value. However, certain values of the backbone disorder reduced the threshold voltage before the critical value was reached because the transmission bands shifted toward the Fermi energy. The results of thermal fluctuation modeling indicated that increasing thermal fluctuation (increasing temperature and decreasing frequency) degraded the electrical properties of the DNA modified with C–G base pairs but enhanced those of the DNA modified by G–C base pairs. This trend, however, did not always hold for all frequency values for the latter DNA type
Characterization of Cellulase Enzyme Produced by Two Selected Strains of Streptomyces Macrosporeus Isolated from Soil in Indonesia
No full textThis study was conducted to characterize the cellulase enzymes produced by Streptomyces macrosporeus BB 32 and S. microspores KRC 21. D, which were isolated from Tanjung Pendam, Belitung Island, and from Cibodas Botanical Garden, Indonesia, respectively. The optimal activity of the enzymes was analyzed using parameters such as incubation time, pH, temperature, carboxymethylcellulose (CMC) concentration. The effect of the addition of some metal ions as activators or inhibitors was also analyzed spectrophotometrically at l 540 nm. Results demonstrated that the activity of the cellulase enzymes of S. macrosporeus BB 32 and S. macrosporeus KRC 21 D reached the optimum level after 2 and 5 days of incubation and at pH values of 8.0 and 6.0, temperatures of 35 °C and 50 °C, and CMC concentrations of 1.75% and 2%, respectively. S. macrosporeus BB 32 cellulase was activated by the cations CuCl2, MgCl2, and ZnCl2 but inhibited by NaCl and CoCl2, reducing its activity. The cellulase of S. macrosporeus KRC 21.D was activated by the cation NaCl and by the divalent cations CoCl2, CuCl2, MgCl2, and ZnCl2. S. macrosporeus BB 32 was deposited at the Indonesian Culture Collection with the collection number InaCC A454
Blended Film from PVA and Sansevieria trifasciata Dichloromethane Fraction for Reducing Heat Radiation from Smartphones
No full textIt has been reported that the lidah mertua plant (Sansevieria trifasciata) can absorb electromagnetic radiation from various electronic equipment. The current study aimed to make a film layer from polyvinyl alcohol (PVA) and a dichloromethane (DCM) fraction of S. trifasciata to reduce heat radiation from smartphones. S. trifasciata leaves were macerated using ethanol and partitioned with ethyl acetate, DCM, and n-butanol. The DCM fraction was chosen to create the film, for which PVA was also used. The blended film made from PVA and 0.02% DCM reduced heat radiation from smartphones by up to 4.4 °C starting from the first minute of use; its heat reduction remained stable until the 20th minute. Based on these results, it was determined that the active compounds in the DCM fraction are closely related to saponin-type steroids