Molecular characterization and n use efficiency of LeAlaAT ‘Mekongga’ transgenic rice lines

Genetic engineering is one of the strategies for developing nitrogen (N)-use-efficient rice (Oryza sativa) varieties. One gene that plays an indirect role in N metabolism is alanine aminotransferase (AlaAT). It can efficiently increase N content and crop yield. In a previous study, the tomato AlaAT gene (LeAlaAT) was successfully isolated and introduced into ‘Mekongga’ rice. The present research was conducted during 2018 and 2019 at the Indonesian Center for Agricultural Biotechnology and Genetic Resources Research and Development (ICABIOGRAD), Bogor, Indonesia. The objectives of the present study were to perform the molecular characterization of LeAlaAT ‘Mekongga’ rice lines on the basis of the hpt marker gene, the direct PCR of the LeAlaAT fragment, and the phenotypic evaluation of the selected LeAlaAT T1 ‘Mekongga’ rice lines in response to different N fertilizer rates (0 kg ha−1 [control] and 60, 90, and 120 kg ha−1). This research involved three activities, namely (1) Southern blot analysis, (2) direct PCR, and (3) N use efficiency (NUE) test of ‘Mekongga’ transgenic lines. Southern blot analysis revealed that in T0 transgenic lines, the copy number of the hpt marker gene varied from 1 to 3. Direct PCR confirmed the presence of the AlaAT fragment in the T1 generation of five ‘Mekongga’ transgenic lines. The five transgenic lines showed high panicle number, biomass weight, shoot dry weight, and total grain weight under 120 kg ha−1 nitrogen. The high agronomical NUE of transgenic lines under 120 kg ha−1 N implied that the transgenic rice lines have the potential for efficient N use at a certain minimum level of N (120 kg ha−1 of nitrogen) and should be further evaluated at high N levels.

A Model System for Sensitive Detection of Viable E. coli Bacteria Combining Direct Viability PCR and a Novel Microarray-Based Detection Approach

We established an innovative approach that included direct, viability, and nested PCR for rapid and reliable identification of the fecal indicator organism Escherichia coli (E. coli). Direct PCR enabled successful amplification of the target uidA gene, omitting a prior DNA isolation or purification step. Furthermore, we applied viability PCR (v-PCR) to ensure the detection of only relevant viable bacterial cells. The principle involves the binding of propidium monoazide (PMA), a selective nucleic acid intercalating dye, to accessible DNA of heat killed bacteria cells and, consequently, allows viable and heat killed E. coli cells to be discriminated. To ensure high sensitivity, direct v-PCR was followed by a nested PCR step. The resulting amplicons were analyzed by a rapid 30 min microarray-based DNA hybridization assay for species-specific DNA detection of E. coli. A positive signal was indicated by enzymatically generated silver nanoparticle deposits, which served as robust endpoint signals allowing an immediate visual readout. The presented novel protocol allows the detection of 1 × 101 viable E. coli cells per PCR run.

Confirmación taxonómica de Gelidium americanum (Gelidiaceae, Rhodophyta) en Tabasco, México, usando un enfoque morfológico y molecular

Antecedentes y Objetivos: Gelidium americanum se distribuye ampliamente en la costa Atlántica de México; sin embargo, hasta ahora no se han realizado estudios que confirmen su identidad taxonómica utilizando marcadores moleculares y caracteres morfológicos. El objetivo del presente trabajo fue confirmar la identidad taxonómica con un enfoque morfológico y molecular, de los especímenes identificados como G. americanum recolectados previamente en la laguna costera de Mecoacán, Tabasco, México.Métodos: Se recolectaron tres especímenes de G. americanum en la laguna Mecoacán, Tabasco, México. El material se analizó morfológicamente, mediante observaciones en un microscopio estereoscópico y microscopio óptico. Para el análisis molecular se extrajo ADN de los talos muestreados empleando el método CTAB; se amplificaron los marcadores rbcL y COI-5P con el kit Phire Plant Direct (PCR), las secuencias fueron editadas en Bioedit y alineadas en Clustal W. Enseguida se hizo un análisis de Máxima Verosimilitud en RaxML, otro de Inferencia Bayesiana en MrBayes y se calcularon las distancias genéticas en MEGA. Resultados clave: Las secuencias obtenidas en el presente estudio para los marcadores rbcL y COI-5P se anidaron en el clado de las muestras identificadas previamente con marcadores moleculares como Gelidium americanum. Además, las distancias genéticas fueron mínimas, los caracteres morfológicos coincidieron con lo descrito previamente para otras localidades del Atlántico, a pesar de contar con un limitado número de especímenes.Conclusiones: Utilizando marcadores moleculares y caracteres morfológicos, se confirma la presencia de Gelidium americanum en la laguna Mecoacán a pesar de presentar características ambientales diferentes a las que habitualmente se han descrito para esta especie.

Comparison and Validation of Ichthyoplankton DNA Extraction Methods

Ichthyoplankton is the cluster of planktonic organisms that consists of fish eggs and larvae. These planktonic stages belong to the temporary zooplankton, representing future exploitable stocks. The study of the early ontogenesis of fish plays a key role in the understanding and evaluation of these populations through the study of their abundance and their spatio-temporal distribution. To better understand and protect these fisheries resources, it is essential to identify the different stages of fish embryonic development. This identification is usually performed using the classical method, based on morphological criteria under a binocular magnifying glass; however, this methodology is not always sufficient and is time consuming and, therefore, it is necessary to rely increasingly on molecular tools. The major problem with these tools is the yield and quality of the nucleic acids extracted from ichthyoplankton, especially in the case of eggs, which are small. Several methods have been used for DNA extraction from ichthyoplankton, either automated or manual, but very often from larvae or adults. In the present work, five fish egg DNA extraction protocols were compared based on their DNA yield and extraction quality, verified by agarose gel electrophoresis and quantitative PCR amplification. The results showed that extraction by our heat-protocol for direct PCR (Hp-dPCR) presents the simplest and cheapest protocol of all the kits used in this study, providing a sufficient quantity and quality of nucleic acids to be used for PCR amplification, and being within the reach of third world laboratories that often do not have sufficiently large budgets to obtain automated kits.

Genotyping Arabidopsis T-DNA lines v1

This protocol is used for genotyping Arabidopsis seedlings to test for the presence of a transfer DNA (T-DNA) insertion. By using two primer sets it is possible to determine whether a seedling is homozygous, heterozygous or azygous for an insertion in the predicted genomic location. To identify lines with T-DNA insertions in a gene of interest, you need the Arabidopsis Genome Identifier (AGI) number corresponding to the genomic locus (e.g. RCS1A = AT1G67090), then visit the Salk Institute T-DNA Express site to find all the mapped insertions at your locus of interest. Genotyping primers have been pre-designed for each T-DNA line, these can be retrieved from the Salk Institute T-DNA primer site, and ordered at any supplier of DNA oligonucleotides before starting the protocol. In the US T-DNA lines can be purchased from the Arabidopsis Biological Resource Center (ABRC) and in the UK and EU from the European Arabidopsis Stock Center (NASC). Recommended reading http://signal.salk.edu/tdnaprimers.2.html Setting up the PCR reaction Genotyping is performed with the Phire Direct PCR Mix, this includes the polymerase, nucleotides and salts necessary for amplification. We use the “dilution protocol” which involves taking a small leaf disk and homogenizing it in dilution buffer using a gel tip (see manufacturer’s instructions for more details.)

Genotyping Arabidopsis T-DNA lines v3

This protocol is used for genotyping Arabidopsis seedlings to test for the presence of a transfer DNA (T-DNA) insertion. By using two primer sets it is possible to determine whether a seedling is homozygous, heterozygous or azygous for an insertion in the predicted genomic location. To identify lines with T-DNA insertions in a gene of interest, you need the Arabidopsis Genome Identifier (AGI) number corresponding to the genomic locus (e.g. RCS1A = AT1G67090), then visit the Salk Institute T-DNA Express site to find all the mapped insertions at your locus of interest. Genotyping primers have been pre-designed for each T-DNA line, these can be retrieved from the Salk Institute T-DNA primer site, and ordered at any supplier of DNA oligonucleotides before starting the protocol. In the US T-DNA lines can be purchased from the Arabidopsis Biological Resource Center (ABRC) and in the UK and EU from the European Arabidopsis Stock Center (NASC). Recommended reading http://signal.salk.edu/tdnaprimers.2.html Setting up the PCR reaction Genotyping is performed with the Phire Plant Direct PCR Mix, this includes the polymerase, nucleotides and salts necessary for amplification. We use the “dilution protocol” which involves taking a small leaf disk and homogenizing it in dilution buffer using a gel tip (see manufacturer’s instructions for more details.)

Improved direct lysis PCR amplification method of microalgal culture for sequencing and species identification

Molecular approach plays important role in species identification for microalgae which involves sequencing of specific DNA barcode present in the genome. This approach involved preparation of template DNA for polymerase chain reaction (PCR) which is time consuming and requires large amounts of algal cells. Microalgal direct PCR have been used frequently for species identification, which simplified the DNA isolation procedure. However, the recent attempts to amplify the rbcL gene of microalga using the previously reported protocol led to poor repeatability. In this study, Nannochloropsis gaditana NIES-2587 was cultured in f/2 liquid medium. The culture growth was estimated on optical density value and the lysis process was improved using gradual temperature procedure during the PCR process. The same culture was extracted using manual DNA extraction method for comparison. The DNA obtained from both methods were amplified using RbclN primer pair to amplify 1486 bp partial sequence of Nannochloropsis rbcL gene, followed by the sequencing of the PCR product. Molecular identification based on the sequence result and BLAST analysis indicated that direct PCR and manual DNA extraction methods successfully produced high sequences result and confirmed the identity of microalgae species into N. gaditana strain CCMP527 with a genetic similarity of >99%.

Use of Direct PCR Technique Without DNA Extraction in Confirmation Test for Salmonella typhimurium Bacteria on Meatball Samples

The use of direct PCR technique without DNA extraction in the confirmation test for Salmonella typhimurium ATCC 14028 bacteria on meatball samples was carried out in the Food and Drug molecular biology testing laboratory Administration in Gorontalo. The basis of this research is to have an impact on economic value in carrying out the confirmation test for S. typhimurium ATCC 14028, where testing is carried out conventionally, namely DNA extraction, which requires a large amount of money. Hence, it is necessary to innovate to modify the testing phase so that it is more effective and efficient. The purpose of this study was to see whether the direct PCR technique without DNA extraction can be done for the confirmation test of S. typhimurium ATCC 14028 on meatball samples. This study's sample consisted of 20 types of meatball samples spiked with S. typhimurium ATCC 14028 cultures. The method used in this study was qPCR analysis using the SYBR Green method. Data analysis was carried out based on 2 main criteria: (1) Ct analysis and (2) Tm analysis. Real-time PCR analysis results obtained Ct values ​​in the range 14.14 - 15.20 with an average of 14.82 and Tm values ​​85.20 - 86.30 with an average of 85.79. Based on these data, it can be concluded that using direct PCR can be used for testing confirmation of S. typhimurium ATCC 14028 on meatball samples.

Detection of Pathogens of Acute Febrile Illness Using Polymerase Chain Reaction from Dried Blood Spots

Quantitative polymerase chain reaction (qPCR) of dried blood spots (DBS) for pathogen detection is a potentially convenient method for infectious disease diagnosis. This study tested 115 DBS samples paired with whole blood specimens of children and adolescent from Burkina Faso, Sudan, and Madagascar by qPCR for a wide range of pathogens, including protozoans, helminths, fungi, bacteria, and viruses. Plasmodium spp. was consistently detected from DBS but yielded a mean cycle threshold (Ct) 5.72 ± 1.6 higher than that from whole blood samples. A DBS qPCR Ct cutoff of 27 yielded 94.1% sensitivity and 95.1% specificity against the whole blood qPCR cutoff of 21 that has been previously suggested for malaria diagnosis. For other pathogens investigated, DBS testing yielded a sensitivity of only 8.5% but a specificity of 98.6% compared with whole blood qPCR. In sum, direct PCR of DBS had reasonable performance for Plasmodium but requires further investigation for the other pathogens assessed in this study.