Answer:
Background
During the course of a bacterial infection, the rapid identification of the causative agent(s) is necessary for the determination of effective treatment options. We have developed a method based on a modified broad-range PCR and an oligonucleotide microarray for the simultaneous detection and identification of 12 bacterial pathogens at the species level. The broad-range PCR primer mixture was designed using conserved regions of the bacterial topoisomerase genes gyrB and parE. The primer design allowed the use of a novel DNA amplification method, which produced labeled, single-stranded DNA suitable for microarray hybridization. The probes on the microarray were designed from the alignments of species- or genus-specific variable regions of the gyrB and parE genes flanked by the primers. We included mecA-specific primers and probes in the same assay to indicate the presence of methicillin resistance in the bacterial species. The feasibility of this assay in routine diagnostic testing was evaluated using 146 blood culture positive and 40 blood culture negative samples.
Explanation:
Results
Comparison of our results with those of a conventional culture-based method revealed a sensitivity of 96% (initial sensitivity of 82%) and specificity of 98%. Furthermore, only one cross-reaction was observed upon investigating 102 culture isolates from 70 untargeted bacteria. The total assay time was only three hours, including the time required for the DNA extraction, PCR and microarray steps in sequence.
It measures the total rate at which photosynthesis or chemosynthesis happens in a system.
Answer:
1: Light-dependent reactions:
Reactants: H2O, ADP, NADP
Products: O2, ATP, NADPH
Location: Thylakoid membranes of chloroplasts in cells of leaves
2: Light-independent reactions
Reactants: CO2, H2O, ATP, NADPH
Products: C6H12O6 (glucose), ADP, NADP
Location: Stroma of chloroplasts in leaf cells
Explanation:
Photosynthesis takes place in two stages:
1: Light-dependent reactions: This stage includes splitting of water in the presence of sunlight and release of electrons and oxygen gas. The electrons are channeled into the electron transport chain and result in the formation of ATP and NADPH. This stage includes photosystem I and II present in the thylakoid membrane. Hence, light-dependent reactions of photosynthesis occur in the thylakoid membrane of chloroplasts and form ATP and NADPH.
2: Light-independent reactions: Also called as Calvin cycle, the light-independent reactions use ATP and NADPH formed during light reactions of photosynthesis to fix CO2 into glucose. The enzymes of the Calvin cycle are present in the stroma of chloroplasts and hence, this stage of photosynthesis occurs in the chloroplast stroma.
