This study aimed to identify human DNA from mixing human and chicken blood samples by utilizing Polymerase Chain Reaction (PCR) and cytochrome b gene primer. The cytochrome b gene is a gene located in mitochondrial DNA and has high variation of sequence relation between one species and another. PCR analysis was performed using human cytochrome b gene primer in variation of DNA templates (0 ng, 0.01 ng, 0.1 ng, 1 ng, 10 ng and 100 ng), human blood percentages (100%, 50%, 40 %, 25%, 10%, 5%, 1%, 0%) and sample age before analysis (0 day, 3 days, 7 days, 10 days, and 15 days). The minimum DNA template obtained in this study was 0.01 ng and minimum percentage of human blood in the mixture was 1%. Blood spots on cloth isolated on days 0, 3, 7, 10 and 15 could still be analyzed and the resulting of DNA band (157 bp) had the same intensity/thickness. From the results of this study, it can be concluded that human blood in the mixture of human and chicken blood can be identified using PCR with specific primers of cytochrome b gene. PCR using specific primer of cytochrome b gene may help forensic practitioners to identify human sample in mixed biological samples.

This study aimed to detect Escherichia coli directly without DNA extraction. The nucleus membrane and cell membranes of the Escherichia coli are composed of a phospholipid bilayer, damaged if heated at 950C. Pre-denaturation and denaturation of PCR were carried out at 950C. The two stages are thought to break down the Escherichia coli cells, so that the DNA that comes out of the cells can directly become a template in the PCR analysis. In this study, PCR analysis was carried out using Escherichia coli culture, Escherichia coli bacteria culture incubated at 950C, and Escherichia coli bacteria cultures incubated at 650C + on ice as templates. The results showed that PCR analysis using Escherichia coli culture directly and Escherichia coli culture incubated at 650C + on ice as templates produced very thin DNA bands with a size of 580 bp. while PCR analysis using Escherichia coli bacteria culture incubated at 950C as a template produced thick DNA bands with a size of 580 bp. This study's results are very useful for saving time and costs in the detection of Escherichia coli bacteria. The sample to be tested does not need DNA isolation as usual, but only needs to be incubated at 950C for 10 minutes.

Since long ago Indonesia used nutritious plants as traditional medicines. Various types of plants in Indonesia can be used as alternative ingredients, one of which is aloe vera. Aloe vera contains saponin and anthraquinone, so aloe vera leaves function as antiseptic and antibacteria. Staphylococcus aureus is a gram-positive coccus bacteria. This bacterium is often found as a normal germ flora in humans. Staphylococcus aureus can cause infections in humans and animals. This study aims to determine the effect of ethanolic extract of Aloe vera leaves in inhibiting Staphylococcus aureus by using maceration extract method. The concentrations used were 20%, 40%, 60%, 80% and 100% with positive control (Erytromycin) and negative control (aquades). The inhibitory zone analysis is done using the table method. Test of ethanol extract of Aloe vera leaves in inhibiting Staphylococcus aureus produced inhibition zones at concentrations of 60%, 80% and 100% with average diameter of 6.94 mm, 6.22 mm and 9.5 mm. The conclusion of this research is the ethanolic extract of Aloe vera leaves can inhibit Staphylococcus aureus in high concentrations

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Abstract-Sperm is one of the body fluids that contain DNA and can be used as evidence or guidance to uncover various criminal cases. Evidence such as sperm can be found in various environments depending on the crime scene, such as being on a submerged cloth. The quality and quantity of DNA obtained from sperm is strongly influenced by the environment where the sperm are found. In this study, we tested the quality and quantity of DNA from sperm spots soaked in freshwater. The quality and quantity of DNA was measured using a spectrophotometer with a wavelength of 260nm and 280nm. The results showed an increase in the quality and quantity of DNA from sperm spots soaked on Day 1, 3 and 7. DNA ribbon also appeared on all samples when the DNA was amplified with STR primers at D21S11 and D13S317 locus.