Judul: Penapisan Lektin dari Alga Hijau Asal Pantai Sepanjang, Y ogyakarta dan Binuangeun, Banten
Abstrak: Lectins are carbohydrate binding proteins that are reversible and have ability to agglutinate. Lectins derived from algae have several advantages, such as having low molecular mass, able to bind specific complex oligosaccharides and glycoproteins and they do not require divalent cations for their biological activity. This research aims to screen lectins of green algae from the coastal of Sepanjang, Yogyakarta and Binuangeun, Banten. This research consists of four stages: 1) sampling and identification of green algae; 2) extraction of the algal sample using Tris Buffer Saline (TBS) and Phosphate Buffer Saline (PBS); 3) hemagglutination test of the crude extract using rabbit eritrocytes and group A, B, and O of human eritrocytes, both native and enzyme treated erithrocytes; 4) analysis of total protein content using the BCA protein assay kits. Eleven species of green algae were collected and extracted. Five species of the algae (Cladhopora patentiramea, Ulva fasciata, Halimeda macroalba, Caulerpa racemosa var. macrophysa, dan Halimeda micronesica) showed hemagglutination activity on human erithrocytes. However, hemagglutination test of the other species (Ulva reticulata, Caulerpa sertulaioides, Caulerpa racemosa var. peltata, Chaetopmorha crassa, Enteromorpha intestinalis, dan morfospecies 1.) showed negative result on human erithrocytes. The hemagglutination activity of all the algae was positive on rabbit erithrocytes. Hemagglutination activity of all the algae except Ulva fasciata and Halimeda macroalba on the trypsin treated erithrocytes was lower than the native erithrocytes. A total of 5 species of green algae which showed activity against human erythrocytes, specifically on either O, A, and B blood group. The high total protein content of the algal extract did not positively correlated with the hemagglutination activity.
Keyword: Bogor Agricultural University (IPB), lectins., hemagglutination, green algae, glycoproteins, chlorophyta

Judul: Aktivitas Antibakteri dan Antioksidan Alga Hijau Halimeda gracilis dan Halimeda macroloba dari Kabupaten Administrasi Kepulauan Seribu
Abstrak: Rumput laut merupakan salah satu produsen primer di ekosistem perairan laut. Sebagian jenis rumput laut juga memiliki nilai ekonomis sebagai penghasil hidrokoloid (alginat, agar dan karagenan) yang secara luas digunakan dalam berbagai industri makanan dan farmaseutika. Metabolit sekunder yang diproduksi pada rumput laut biasanya untuk keperluan pertahanan diri dari gangguan predator alga seperti ikan, echinodermata, krustasea ataupun moluska. Tujuan penelitian ini adalah menentukan : 1) aktivitas antibakteri dan antioksidan alga hijau H. gracilis dan H. macroloba, 2) pengaruh perlakuan fisik dan induksi bakteri terhadap aktivitas antibakteri dan antioksidan, 3) kandungan komponen bioaktif, serta 4) fraksi aktif antibakteri. Ekstraksi dilakukan dengan metode maserasi menggunakan metanol dan dipekatkan dengan rotary evaporator. Ekstrak H. gracilis dan H. macroloba diuji terhadap Staphylococcus aureus dan Escherichia coli. Fraksinasi dilakukan dengan metode partisi cair-cair dan solid phase extraction (SPE). Uji antioksidan dilakukan dengan metode DPPH dan senyawa bioaktif ditentukan dengan uji fitokimia. Rendemen ekstrak kasar H. gracilis yang diperoleh adalah sekitar 18.55-23.94%, sedangkan rendemen ekstrak kasar pada H. macroloba sekitar 13.49-17.88%. Aktivitas antibakteri ekstrak kasar H. gracilis lebih tinggi dibandingkan dengan H. macroloba pada kedua bakteri uji. Perlakuan induksi bakteri (Vibrio harveyi dan Stenotrophomonas maltophilia) pada alga hijau H. gracilis menyebabkan penurunan aktivitas antibakteri pada bakteri uji E. coli. Induksi bakteri menyebabkan tidak adanya aktivitas antibakteri ekstrak kasar H. gracilis terhadap bakteri uji S. aureus. Perlakuan potong dan induksi bakteri pada H. macroloba terlihat meningkatkan aktivitas antibakterinya terhadap kedua bakteri uji. Aktivitas antibakteri tertinggi terlihat pada fraksi B H. gracilis utuh dengan zona hambat pada S. aureus dan E. coli masing-masing 7.00 mm dan 6.00 mm pada konsentrasi 0.2 mg/sumur. Zona hambat antibakteri hanya terlihat pada fraksi etil asetat setelah dilakukan partisi cair-cair. Hasil uji antioksidan menunjukkan ekstrak H. gracilis memiliki aktivitas antioksidan yang lebih baik dibandingkan H. macroloba pada semua perlakuan. Berdasarkan hasil uji fitokimia pada ekstrak kasar diketahui bahwa ekstrak H. gracilis mengandung fenol dan steroid, sedangkan ekstrak H. macroloba mengandung fenol dan saponin. Fraksi B diduga merupakan senyawa golongan steroid karena terbentuk bercak warna ungu ketika disemprot dengan pereaksi anisaldehida-asam sulfat.
Keyword: alga hijau, antibakteri, antioksidan, fraksinasi

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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