Judul: Biologi Reproduksi Ikan Layur (Trichiurus lepturus Linnaeus, 1758) di Teluk Palabuhanratu, Sukabumi. Jawa Barat
Abstrak: Ikan layur merupakan salah satu ikan yang memiliki nilai ekonomis penting dan telah menjadi komoditas ekspor. Permintaan yang terus meningkat menyebabkan peningkatan upaya penangkapan yang dapat mengancam ketersediaan sumberdaya ikan layur. Penelitian ini bertujuan menganalisis aspek biologi reproduksi ikan layur di Teluk Palabuhanratu. Penelitian dilaksanakan pada bulan Mei hingga September 2017. Pengambilan ikan contoh menggunakan metode penarikan contoh acak sederhana. Ukuran ikan layur yang diteliti sebanyak 639 ekor dengan nisbah kelamin antara jantan dan betina sebesar 1:2,20 atau didominasi ikan betina. Potensi reproduksi ikan layur betina tergolong tinggi dengan rata-rata 13 018 butir telur. Musim pemijahan ikan layur diduga terjadi selama periode pengamatan dan puncak pemijahan terindikasi terjadi pada bulan Juni dengan tipe pemijahan partial spawner. Ikan layur jantan mencapai ukuran pertama kali matang gonad (Lm) lebih awal dibandingkan dengan ikan layur betina, yaitu pada ukuran 641,37 mm untuk jantan dan 755,28 mm untuk betina.
Keyword: ikan layur (Trichiurus lepturus), musim pemijahan, potensi reproduksi, Teluk Palabuhanratu

Judul: Biologi Reproduksi Ikan Layur (Trichiurus lepturus Linnaeus, 1758) di Perairan Selat Sunda.
Abstrak: Ikan layur (Trichiurus lepturus) merupakan salah satu ikan ekonomis penting dan mulai diperhitungkan sebagai komoditi ekspor yang potensial. Tingginya permintaan akan ikan layur mengakibatkan tingginya upaya penangkapan yang dapat mengancam ketersediaan ikan layur di perairan. Penelitian ini dilakukan untuk mengkaji aspek biologi reproduksi, seperti rasio kelamin, ukuran pertama kali matang gonad, periode pemijahan, tipe pemijahan, dan fekunditas ikan layur. Pengambilan ikan contoh dilakukan pada bulan April-Agustus 2015 di PPP Labuan, Banten. Metode yang digunakan dalam pengambilan ikan contoh adalah penarikan contoh acak berlapis (stratified random sampling). Rasio kelamin antara ikan layur jantan dan betina adalah 0,84. Hasil analisis Spearman-Karber menunjukkan ukuran pertama kali matang gonad ikan layur adalah 536,29 untuk jantan dan 566,82 mm untuk betina, sedangkan hasil pengamatan menunjukkan ukuran ikan layur terkecil yang telah matang gonad adalah 401 mm untuk jantan dan 454 mm untuk betina. Ikan layur memijah sekitar bulan April, Mei, dan Juli. Tipe pemijahan ikan layur adalah batch spawners. Fekunditas ikan layur berkisar 1200-21400 butir telur.
Keyword: Biologi reproduksi, ikan layur, Trichiurus lepturus, Selat Sunda, Labuan

Judul: Glucose biosensor using a glucose dehydrogenase flavin adenine dinucleotide electrochemically immobilized on zeolite nanoparticles
Abstrak: A glucose biosensor was developed to measure blood glucose levels. The performance of these new glucose biosensors was continuously improved, producing better performance and stability. The technique selection and immobilization matrix are key factors for biosensor development, so that the prospecting of materials that can be used as a matrix for supporting enzyme, continue to be explore. The purpose of this study was to determine the activity and stability of the enzyme glucose dehydrogenase (GDH) that were immobilized on zeolite nanoparticles (NPZ) and determine the kinetic parameters and analytical performance by electrochemical methods. The resulting enzyme electrode with NPZ and enzyme electrode with zeolite A showed a high activity against the enzyme electrode glucose than without NPZ. The reaction kinetics of third electrodes of enzyme followed the Dixon equation. The 𝐼����𝑚����𝑎����𝑥����𝑎����𝑝����𝑝���� values for enzyme electrode without NPZ, with NPZ, and with zeolite A were 27.25 μA, 77.52 μA, and 48.54 μA, respectively. The 𝐾����𝑀����𝑎����𝑝����𝑝���� values for GDH enzyme that immobilized on the NPZ were 1.16 mM, 12.30 mM for GDH enzyme that immobilized on zeolite A and 0.95 mM for GDH enzyme immobilization without NPZ. The enzyme electrode without NPZ, with NPZ, and with zeolite A also showed a high sensitivity with value for the sensitivity were 0.58 μA mM-1, 0.81 μA mM-1, and 2.51 μA mM-1, respectively. The third enzyme electrodes showed different linear area with range for the enzyme electrode without NPZ, with NPZ and with zeolite A were 1.00-15.00 mM, 2.00-20.00 mM, and 0.06-10.00 mM, respectively. The blood glucose level of normal person ranged from 4 to 6 mM, so that the enzyme electrode with NPZ and without NPZ are suitable for use in the determination of the concentration of blood glucose. While the enzyme electrode with zeolite A has a smaller range so it is more suitable to use in the determination of glucose concentration in the foods or beverages. The enzyme electrode with NPZ and the enzyme electrode with zeolite A showed a good accuracy with relative error values were 3.84% and3.48%, respectively. Repeatability measurements also showed a good precission results with relative standard deviation values (%RSD) for the enzyme electrode with NPZ and enzyme electrode with zeolite A were 3.83% and 3.16%, respectively. By combining two immobilization techniques, physical adsorption on zeolite and entrapment on carbon paste, high enzymatic activity, good accuracy, and repeatability was attained. The enzyme electrode with NPZ and the enzyme electrode with zeolite A demonstrated a good electrochemical response toward glucose, allowing it to detect blood glucose levels and glucose levels in foods and beverages.
Keyword: glucose biosensor, immobilization, zeolite