Judul: Expression Analysis of Lipid Biosynthesis-Related bZIP1 and LEC1 Ortholog Genes in Chlorella vulgaris Cultures Under Nitrogen Deficiency Conditions, Expression Analysis of Lipid Biosynthesis-Related bZIP1 and LEC1 Ortholog Genes in Chlorella vulgaris Cultures Under Nitrogen Deficiency Conditions
Abstrak: Microalgae can produce energy-rich compounds, especially triacylglycerol, for biofuel production. This study aims to analyze the expression of lipid biosynthesis-related bZIP1 and LEC1 ortholog genes in the culture of Chlorella vulgaris under optimum and nitrogen-deficiency conditions and to identify the microalgae isolates through molecular approach. The C. vulgaris samples were cultured and subjected to nitrogen-deficiency treatment in NaNO3 compound with a control-to-treatment ratio 4:1 and final concentrations of 100 and 25 mg/L. Cell harvesting was performed on exponential phase based on the cell growth curve calculated using haemacytometer. Sequencing techniques confirmed the taxonomic status of microalgae isolates on 18S rRNA gene fragments. The orthologous genes were analyzed in the GeneBank database using the BLAST algorithm based on the similarity of protein sequences (BLASTp and tBLASTn). Total RNA isolation, cDNA synthesis, and qRT-PCR performed the gene expression analysis. Cell density calculation results showed that nitrogen-deficiency decreased the C. vulgaris growth. Sequence analysis of the 18S rRNA gene fragment revealed similarity with Chlorella. The qRT-PCR analysis results indicate a significant upregulation of the LEC1 ortholog gene by 2-fold compared to the control. Differently, the upregulation of the bZIP1 ortholog gene is not statistically significant, showing a 1.5-fold increase compared to the control.
Keyword: nitrogen-deficiency, bZIP1, LEC1, qRT-PCR

Judul: Expression of Orthologous bZIP1 and LEC1 Genes Related to Lipid Biosynthesis in Microalgae Nannochloropsis oceanica under Nitrogen Deficiency Culture Conditions
Abstrak: Mikroalga dimanfaatkan sebagai bahan baku biodiesel karena kemampuannya mengakumulasi triasilgliserol (TAG) yang tinggi. Gen bZIP1 dan LEC1 diketahui sebagai faktor transkripsi yang terlibat dalam meregulasi metabolisme lipid dan peningkatan TAG. Penelitian ini bertujuan menganalisis ekspresi gen ortolog bZIP1 dan LEC1 pada Nannochloropsis oceanica dalam kondisi kultur defisiensi nitrogen menggunakan teknik Quantitative Real-Time PCR (qRT-PCR). Sampel N. oceanica dikultur pada media Walne dan diberi perlakuan kondisi defisiensi nitrogen dengan perbandingan antara kontrol dengan perlakuan adalah 4:1 dan konsentrasi akhir NaNO3 100 dan 25 mg/L. Isolat N. oceanica berbasis morfologi dikonfirmasi dengan teknik sekuensing pada dua fragmen gen 18s rRNA dan diyakini pada tingkat genus merupakan Nannochloropsis sp.. Gen-gen ortolog bZIP1 dan LEC1 pada N. oceanica dianalisis menggunakan algoritma Basic Local Alignment Search Tool (BLAST) berdasarkan kemiripan sekuens protein (BLASTp dan tBLASTn) pada database genus Nannochloropsis. Primer dirancang dari sekuens nukleotida kedua gen tersebut. Hasil analisis ekspresi relatif dengan teknik qRT-PCR menunjukkan adanya peningkatan signifikan ekspresi gen ortolog bZIP1 sebesar 10,8 kali lipatnya sementara LEC1 tidak signifikan hanya 1,2 kali pada perlakuan kultur defisiensi nitrogen. Penelitian ini diharapkan menambah informasi kandidat gen yang dapat direkayasa sehingga diekspresi berlebih pada N. oceanica untuk menghasilkan strain yang memiliki tingkat produksi TAG yang lebih tinggi., Microalgae are a promising biodiesel feedstock due to their ability to accumulate substantial amounts of triacylglycerols (TAG). The bZIP1 and LEC1 genes are crucial transcription factors, governing lipid metabolism and enhancing TAG accumulation. This research aims to investigate the expression of orthologous bZIP1 and LEC1 genes in Nannochloropsis oceanica under nitrogen deficiency culture conditions, employing Quantitative Real-Time PCR (qRT-PCR) technique. The N. oceanica samples were cultured in Walne’s medium and subjected to nitrogen deficiency conditions with a control-to-treatment ratio of 4:1 using final NaNO3 concentrations of 100 and 25 mg/L. Morphologically identified N. oceanica isolate was confirmed through sequencing of two 18s rRNA gene fragments, indicating its genus-level classification as Nannochloropsis sp. Orthologous bZIP1 and LEC1 genes in N. oceanica were analyzed using Basic Local Alignment Search Tool (BLAST) algorithm, specifically BLASTp and tBLASTn, based on protein sequence similarity within the Nannochloropsis genus database. Primers were designed from the nucleotide sequences of both genes. The qRT-PCR results revealed a significant 10,8-fold increase in the expression of the bZIP1 orthologous gene, while LEC1 showed non-statistically significant 1,2-fold increase under nitrogen deficiency. This study contributes valuable insights into potential candidate genes for genetic engineering to enhance TAG production in N. oceanica strains.
Keyword: bZIP1, LEC1, Microalgae, qRT-PCR, triacylglycerol

Judul: Perancangan jalur interpretasi wisata sejarah kawasan kota tua Jakarta
Abstrak: Tapak perancangan berupa jalur interpretasi yang terletak di dalam wilayah administrasi kota Jakarta Barat dan melalui Jl. Stasiun, Jl. Pintu Besar Selatan dan Utara, Jl. Kali Besar timur dan barat, Jl. Cengkeh, Jl. Pos, dan Jl. Lada. Aksesibilitas menuju tapak mudah dengan berbagai alternatif sarana transportasi. Tata guna lahan kawasan 78% terdiri dari perkantoran perdagangan.
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