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Escherichia coli (E. coli) is an indicator bacteria that is often used to assess the level of microbial contamination in food and plants. This study aims to isolate and identify the presence of E. coli from Coleus amboinicus plants which are known to have antibacterial activity. Fresh leaf samples of C. amboinicus were taken from the home yard environment. Isolation was carried out using the serial dilution method and planting on eosin methylene blue (EMB) placement media. Identification was carried out based on colony morphology, Gram staining, and biochemical tests including IMViC (Indole, Methyl Red, Voges-Proskauer, Citrate). The results showed the presence of metallic green colonies on EMB, which showed the characteristics of E. coli. Biochemical tests showed Indole (+), Methyl Red (+), Voges-Proskauer (-), and Citrate (-), which confirmed the isolate as E. coli. The presence of E. coli in C. amboinicus indicates the possibility of environmental fecal contamination, and is a concern in the processing and consumption of this medicinal plant.

This study aims to evaluate the effectiveness of using Methylene Blue stain in the microscopic observation of frog skin cell structures. Cell staining is an essential technique in histological studies, as it enhances the visibility of cellular components that are otherwise difficult to observe without contrast. Methylene Blue is known to have a high affinity for acidic components within the cell nucleus, thus providing a clearer depiction of nuclear and cell membrane structures. This research employed a descriptive experimental method by preparing frog skin tissue samples stained with Methylene Blue and observing them under a light microscope. The results indicated that Methylene Blue staining produced high contrast, allowing for the identification of hexagonal-shaped cells and dark, centralized nuclei. The obtained microscopic images revealed a uniform distribution of cells with clearly observable morphological structures. Therefore, Methylene Blue is proven to be effective in enhancing the microscopic visualization of epithelial tissue in frog skin and is recommended for use in both educational and basic biological research contexts.

This study aims to evaluate the effectiveness of using Methylene Blue stain in the microscopic observation of frog skin cell structures. Cell staining is an essential technique in histological studies, as it enhances the visibility of cellular components that are otherwise difficult to observe without contrast. Methylene Blue is known to have a high affinity for acidic components within the cell nucleus, thus providing a clearer depiction of nuclear and cell membrane structures. This research employed a descriptive experimental method by preparing frog skin tissue samples stained with Methylene Blue and observing them under a light microscope. The results indicated that Methylene Blue staining produced high contrast, allowing for the identification of hexagonal-shaped cells and dark, centralized nuclei. The obtained microscopic images revealed a uniform distribution of cells with clearly observable morphological structures. Therefore, Methylene Blue is proven to be effective in enhancing the microscopic visualization of epithelial tissue in frog skin and is recommended for use in both educational and basic biological research contexts.

Coal is an organic mineral from ancient plant remains that settles and goes through physical or chemical processes over a period of up to millions of years. Coal is used as a source of steam-powered electrical energy through combustion which produces fly ash waste. fly ash contains various chemical materials such as SiO2; Al2O3; Fe2O3. The potential chemical content makes fly ash which can be used as an adsorbent for heavy metals and dyes by forming silica xerogel. To increase the silica oxide content in fly ash, a washing process is carried out with various solvents. Research on the adsorption of methylene blue dye using silica xerogel from fly ash with variations in contact time. The results showed that silica xerogel from fly ash was able to adsorb methylene blue dye at a contact time of 90 minutes. Adsorption kinetics follows a pseudo second order model with an R2 value that is better than pseudo first order. It can be seen that the R2 value respectively shows a linear regression of 0.703 for pseudo first order and 1 for pseudo second order.

Rice husk is a waste originating from agricultural waste that has not been utilized properly. The purpose of this study was to compare NaOH-activated rice husk activated charcoal with unactivated activated charcoal, and to measure the adsorption capacity of activated charcoal to methylene blue. Gravimetry, volumetry, and spectrophotometry are the analytical techniques used in this analysis. In this study, 1.5 M rice husk activated charcoal with NaOH showed the best results. It showed a water content of 8.81%, ash content of 5.87%, volatile matter content of 6.60%, and carbon content of 78.72%. In addition, the results showed that NaOH-activated rice husk activated charcoal has characteristic capabilities and adsorption capacity to methylene blue that meets SNI. The longer it is reasonable, the more rice husk activated charcoal.

The part of the basil plant is the leaves which have various types of benefits if studied further. With the introduction of secondary metabolites, it can be said that basil leaves contain eugenol compounds. The eugenol compound can be used as a reducing agent in the synthesis of TiO2 nanoparticles. The precursor used in the synthesis of TiO2 is titanium isopropoxide which has an oxidation state of +4. By utilizing the green synthesis method, TiO2 was reacted with basil leaf extract and then characterized using XRD and FTIR. The resulting particle size is 10.86 nm. And FTIR shows a wave number of 874.59 which represents the Ti-O functional group. Photocatalytic activity can take advantage of the synthesis of TiO2 nanoparticles by placing the nanoparticles in a methylene blue solution which has a concentration of 20 ppm and varies based on contact time and adsorbent mass. Photocatalytic activity testing obtained a degradation percentage of 79%-84% which varied based on adsorbant mass and contact time. Varying the adsorbant mass and time results in a degradation percentage that increases with each additional mass but will not increase again if it has reached the optimum phase and can reduce the degradation percentage.

Rice in the world consists of several types, including white rice, brown rice, black rice, and brown rice. Rice is also grouped into two groups, namely glutinous rice containing high amylopectin (low amylose) and non-glutinous rice, namely rice with low amylopectin content (high amylose). Amylose content determines the quality of taste, fluffiness and other physical properties. Rice that has a high amylose content has the properties of soft/hard rice, while rice that has a low amylose content has the character of a fluffier rice. This research was conducted with the aim to determine the amylose content found in black rice, especially local West Java. The research was conducted in October 2018 at the BB-PADI Sukamandi Subang laboratory. The tools used are beakers, measuring flasks, funnels, analytical scales, spray bottles, measuring pipettes, and a spectrophotometer. The materials used were Bandung black rice, Subang black rice, Bogor black rice, and Indramayu black rice, amylose standard solution, methylene blue indicator, 0.02 N HCl, distilled water, 95% ethanol solution, NaOH solution, iodine solution, and others. Determination of amylose content using the spectrophotometric method (AOAC, 1999), was carried out in two stages, namely: the Standard Curve Preparation Stage and the Sample Determination Stage. From the research results, the following data were obtained: the amylose content of black rice from Subang was 12.72%w/b, the amylose content of black rice from Bandung was 17.21%w/b, the amylose content of black rice from Bogor was 13.67%w /w and the amylose content of black rice from Indramayu was 21.18% w/w. Based on the results of the study, it can be concluded that black rice from three regions in West Java, namely Bandung, Subang and Bogor, is included in the low amylose content category (10-20%) and black rice from Indramayu is included in the medium amylose content group (20-25%). The lowest amylose content was owned by black rice from Subang with a value of 12.72% and the highest amylose content was owned by black rice from Indramayu with a value of 21.18% w/w.

High microbial contamination in food is an indicator of hygiene that determines the health of food for consumption. Meatballs are a very popular snack in Majene City. Apart from their delicious taste, meatballs also have a relatively cheap price, so they have always been a popular snack alternative. The high nutritional content in meatballs can be a medium for the growth of bacteria so meatballs can be carriers of disease. The aims of this study were to determine the total number of bacterial contaminants and identify the coliform in meatballs at Majene City. The study used a quantitative descriptive method with a sample of 10 traders. The test carried out was culturing bacteria on NA (Nutrient Agar) media to calculate the total number of microbes in meatballs using the Total Plate Count (TPC) method and EMBA (Eosin Methylene Blue Agar) media to determine the presence of coliform bacteria in the sample then continued with gram staining test. The results of the study showed that 3 samples were found on NA media which had microbial contamination levels exceeding the threshold specified in SNI (Indonesian National Standard) 3818:2014 where the highest amount allowed was 1 × 105 cfu/g. Samples that exceeded the threshold namely sample A was 1.33 × 106 cfu/g; sample C was 1.06 × 105 cfu/g; and sample G was 5.8 × 106 cfu/g. There were 5 samples that tested positive for coliform, namely samples A, B, C, D, and G