BackgroundThe neural crest is a group of multipotent cells that emerges after an epithelial-to-mesenchymal transition from the dorsal neural tube early during development. These cells then migrate throughout the embryo, giving rise to a wide variety derivatives including the peripheral nervous system, craniofacial skeleton, pigment cells, and endocrine organs. While much is known about neural crest cells in mammals, birds, amphibians and fish, relatively little is known about their development in non-avian reptiles like snakes and lizards.ResultsIn this study, we show for the first time ever trunk neural crest migration in a snake by labeling it with DiI and immunofluorescence. As in birds and mammals, we find that early migrating trunk neural crest cells use both a ventromedial pathway and an inter-somitic pathway in the snake. However, unlike birds and mammals, we also observed large numbers of late migrating neural crest cells utilizing the inter-somitic pathway in snake.ConclusionsWe found that while trunk neural crest migration in snakes is very similar to that of other amniotes, the inter-somitic pathway is used more extensively by late-migrating trunk neural crest cells in snake.

Perairan darat merupakan salah satu ekosistem yang memunculkan interaksi antara organisme didalamnya dengan kualitas perairan itu sendiri. Baik buruknya parameter kualitas air sangat mempengaruhi keanekaragaman dan struktur komunitas. Plankton merupakan organisme perairan yang keberadaannya dapat menjadi indikator perubahan kualitas biologi perairan dan produktivitas primer perairan sungai. Tujuan dari penelitian ini yaitu untuk mengetahui kelimpahan plankton di perairan darat yang di wakili oleh sungai di dataran rendah Surabaya dan dataran tinggi di sungai Pujon dan Waduk Selorejo. Hasil penelitian identifikasi plankton yang diambil pada 3 tempat yang berbeda, spesies fitoplankton yang melimpah yaitu spesies Melosira sp, Oscillatoria sp, Tabellaria sp, Nitzshia sp dan Spirogyra sp. Sedangkan, untuk spesies zooplankton sendiri yang paling melimpah dari ketiga tempat tersebut yaitu spesies Cyclopoida sp, Mysit sp dan Brachionus sp. Data tersebut dapat di haraokan daoat menjadi data pendahuluan mengenai studi plankton di perairan darat baik di dataran rendah maupun di dataran tinggi.

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This research was done to explore bioactivity of Xylocarpus granatum's stem extract as tyrosinase inhibitor for alternative preventing black spot in Litopenaeus vannamei postharvest. In this research, extraction of bioactive compound from X. granatum stem was done by soaking the stem in 96% methanol for 24h at temperature 29°C. The methanol was evaporated by using rotary evaporator at temperature 50°C. The extract was dilute with distillate water at series of dilutions (10%, 30%, 50%, 70%, 90%, and distillate water as the control), and then immersing L. vannamei into X. granatum's stem extract as much as 10ml for 6h, and finally the data analyzing use the Kruskal Wallis test and the Least Significant Difference (LSD) test with the degree of confident 95%. The result showed that X. granatum's stem extract is able to prevent a black spot of L. vannamei after harvesting process. Furthermore, concentration of 10 % of extract is an effective concentration for preventing a black spot and the control has black spot 0.0360 -0.0373 mm 2 . Article history:Received 11 Pencegahan black spot secara fisik pada pasca panen yaitu cephalothorax udang dihilangkan sehingga menjadi udang head less. Cephalothorax udang telah diketahui mengandung polifenoloxidase, enzim tersebut mampu aktif pada kondisi optimumnya yaitu pH 6 dan suhu 45°C, aktifnya enzim tersebut mengakibatkan timbulnya black spot (Gimenez, 2004). Penghilangan kepala udang bertujuan untuk mengurangi jumlah dan aktivitas polifenoloxidase selama proses pasca panen (Benjakul, 2005).Pencegahan black spot secara kimia pada proses pasca panen yaitu penambahan asam askorbat pada udang sebagai antioksidan, perendaman udang ke dalam air es yang mengandung 100 ppm natrium bisulfit (NaHSO 3 )/sodium bisulfit, perendaman udang ke dalam air es yang mengandung 2 ppm metabisulfit/sodium metabisulfit 2 ppm selama 2 menit, serta pencucian udang dengan air yang mengandung klorin 1-10 ppm (Badan Standarisasi Nasional, 1998).Sulfit (metabisulfit maupun bisulfit) merupakan bahan

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