Insecticidal Activity of Extracellular Protein of PRU8 Isolate against Tenebrio molitor Larvae

Sel ataupun supernatan bebas sel dari kultur cair isolat bakteri entomopatogen PRU8 memiliki toksisitas tinggi terhadap larva Tenebrio molitor. Bioesei protein ekstrasel kasar hasil pengendapan amonium sulfat menunjukkan bahwa toksisitas tertinggi terdapat pada protein yang diendapkan pada kejenuhan amonium sulfat 70%. Pemurnian protein menggunakan kolom Hi Prep 16/60 Sephacryl S-200 HR menghasilkan satu fraksi protein toksin. Mortalitas larva uji yang disuntik dengan 19,2 nanogram toksin murni mencapai 71%. Uji toksisitas menggunakan toksin murni menunjukkan bahwa toksin tersebut termasuk kelompok toksin tipe injeksi. Berdasarkan analisa SDS-PAGE toksin tersebut tersusun atas dua protein dengan berat molekul 116,25 dan 66,24 kD

Aktivitas Antifungi Formula Kitosan-Tripolifosfat Terhadap Infeksi Colletotrichum spp. Pada Cabai

Colletotrichum spp. penyebab penyakit antraknosa banyak menginfeksi tanaman cabai, sehingga perlu dikendalikan dengan agen hayati ramah lingkungan. Tujuan penelitian ini adalah untuk menguji aktivitas antifungi campuran formulasi berbagai konsentrasi kitosan (K) (0.2%, 0.3% dan 0.5%) hasil ekstraksi kitinase isolat E65 dan NaTPP (0.1%) pada ratio [5:2] terhadap penghambatan  pertumbuhan jamur Colletotrichum spp. pada cabai. Daya hambat formulasi K-TPP terhadap pertumbuhan Colletotrichum spp. masing-masing dilakukan dengan metode in vitro (pada media PDA) dan in vivo (pada buah cabai). Konsentrasi K (0.5%) : TPP (0.1%) pada rasio [5:2], menunjukkan daya hambat paling tinggi terhadap infeksi Colletotrichum spp. Penelitian lanjutan perlu dilakukan terhadap aktivitas antifungi berbagai formulasi dan konsentrasi K-TPP lainnya terhadap cabai di lapangan

PROTEIN TOKSININSEKTISIDAL DARI BAKTERI PATOGEN SERANGGA Photorhabdus luminescens HJ

Photorhabdus luminescens HJ is an entomopathogenic bacterium that has a high toxicity against Tenebrio molitor larvae.Toxicity assay of crude extra cellular protein precipitated using ammonium sulphate showed that the highest toxin activity was found in 70 % saturation. Purification of the toxin using Hi Prep 16/60 Sephacryl S-200 HR column exhibited one fraction of toxic protein and three fractions of non-toxic protein. Mortality of T. molitor larvae treated with 19.2 nanogram of toxic fraction was up to 80%. Denatured protein analysis using sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed that the toxic fraction was composed of three proteins, which were 19.5, 42, and 66 kDa respectively. Based on toxin activity bioassay, this toxin type was an injectable toxin and presumably classified as Mcf toxin

Aktifitas Antifungi Kitosan Hasil Hidrolisis Enzimatik Terhadap Penyakit Antraknosa

Anthracnose disease caused by Colletotrichum gloeosporioides is one of an important fungal pathogen on mango fruits during the pre harvest or post harvest stage. The use of chitosan as an alternative method to control the disease is necessary due to its biodegradable, biocompatible and non-toxic effect. Chitosan tripolyphosphate (C-TPP) showed higher inhibition to C. gloeosporioides compared with that of low molecular weight (LMW) chitosan as affected by its particle size. The best of disease inhibitory activity was revealed by C-TPP B [0.2% LMW : 0.1% TPP; (5: 2)] and C [0.2% LMW: 0:08% TPP; (5: 1)] treatments based on  in vitro and in vivo test. Because of the concentration of chitosan and TPP may affect to particle structure, hence the C-TPP formation needs further to be optimized so that the size is getting smaller and stable

Biologi Penggerek Batang Jagung Ostrinia furnacalis Gueneé yang diberi Pakan Buatan

Ostrinia furnacalis is a corn stem-borer that develops complete metamorphosis and all stages in life cycle in corn. This research was aimed to examine several biology aspects of O. furnacalis such as life cycle, egg incubaton period, egg fertility, female fecundity, longevity of imago, and copulation time on artificial diet, based on the previous study. The results of the observations showed that the life cycle of artificial-diet-given O. furnacalis was between 27-34 days range. Female fecundity was 16-452 eggs with fertility rate of 61,97% and 3-5 days renge of egg incubation period. Longevity of imago was between 6-11 days range, and the longevity was longer in female compared to the male. The imago of O. furnacalis copulate on 0-3 days after emerge from pupae and the highest number in on the day 1. Copulation time was occurred at 3-8 hour after scotophase commenced and the highest was at third hour. The artificial diet used in this research can be used for O. furnacalis mass rearing purpose and performed shorter length of egg stage until pupal stage compared to mass rearing with natural diet.&nbsp

Biosintesis nanopartikel perak (AgNP) menggunakan Bacillus firmus E65 dan aktivitasnya terhadap mikroba patogen

Silver (Ag) in ionic form is toxic to microbial cells, but is environmentally friendly and safe for humans. This study aims to synthesize silver nanoparticles (AgNP) using Gram-positive bacterial isolate (B. firmus E65) as a bioreductor and to test its activity as an antimicrobial against Eschericia coli, Xanthomonas oryzae pv. oryzae (Xoo) and the fungus Colletotrichum gloeosporioides under in-vitro assays. AgNP was obtained by adding bacterial culture supernatant B. firmus E-65 to 5mM AgNO3 solution. The formation of AgNP was observed by changing the color of the solution after incubation at 37 °C for 72 hours. The UV-Vis spectrophotometer measurement to AgNP solution showed a maximum wavelength of 425 nm. The particle size of AgNP was 252.1 nm with intensity of 98.90 %. The result of bioassay against E. coli showed the greatest inhibition at 50 % AgNP (degree of inhibition (DI) =96.15 %), followed by 25 % AgNP (DI=76.92 %), and 12.5 % AgNP (DI=53.84 %). The bioassay against Xoo showed the greatest degree of inhibition was at AgNP 50 % (DI=92.85 %), followed by 25 % AgNP  and 12.5 % AgNP (DI=85.71 %). Meanwhile bioassay against C.gloeosporioides, the greatest inhibition  was observed at 25 % AgNP (DI=94.35 %), followed by 50 % AgNP (DI=91.9 %)

KARAKTERISASI KITINASE ISOLAT BAKTERI RHIZOSFIR ASAL CIANJUR DAN AKTIVITASNYA TERHADAP PATOGEN Colletotrichum sp.

Kitinase mampu menghidrolisis kitin dan berpotensi sebagai agen biokontrol. Tujuan penelitian adalah memurnikan dan mengkarakterisasi kitinase dari isolat terpilih, serta menentukan kemampuan kitinolitiknya dalam penghambatan jamur Colletotrichum sp. Aktivitas kitinase ditentukan dengan metode Spindler, sementara kadar protein ditentukan dengan metode Bradford. Produksi kitinase isolat rizobakteri (isolat C5C) menunjukkan aktivitas enzim spesifik tertinggi sebesar 0.0489 U/mg melalui pemurnian parsial NH4SO4 70%, serta dapat meningkatkan kemurnian 13.97 kali dibandingkan ekstrak kasar. Karakterisasi kitinase isolat C5C menunjukkan bahwa enzim aktif optimal  pada suhu 55°C, pH 7, waktu inkubasi 120 menit, serta memiliki nilai Km sebesar 1.300 x 103 mg/L dan Vmaks sebesar 0.0294 mgL-1detik-1. Aktivitas antifungi pada uji in vitro menunjukkan bahwa isolat C5C dapat menghambat pertumbuhan Colletotrichum sp.Kata kunci: biokontrol,Colletotrichum sp.,  kitinase, rizobakter

KARAKTERISASI BAKTERI PENGHASIL ASAM INDOL ASETAT DAN PENGARUHNYA TERHADAP VIGOR BENIH PADI

The ability to produce indole acetic acid (IAA) by endophytic bacteria is one of the basic criteria for the use of bacteria as plant growth promoter agent which is essential for the agricultural production.The objectives of this study were to evaluate the ability of 17 bacterial isolates to produce IAA and its effect on improvement of rice seed germination and molecular identification of the selected isolates based on the 16S rRNA gene. The IAA content was determined using Salkowski method measured by spectrophotometer UV-Vis and the effect of endophytic bacteria inoculation on seed germination was done by in vitro assay. Sequences of the selected isolates 16S rRNA amplified by PCR were analyzed the homology against bacterial 16S rRNA database in Genebank. IAA values ranged from 6.632 to 50.053 mg/L with the highest IAA production shown by isolate 6KJ which was followed by 4PB (41.807 mg/L). Bacterial IAA increased rice seed vigor significantly compared to control. However, bacterial inoculation with different concentrations of IAA did not significantly affect the growth of rice plants. Based on the IAA and its effect on seed vigor, 6KJ, 4PB and 2KB were selected for molecular identification. Results showed that the three isolates belonged to Bacillus genus, 6KJ as B. aryabhattai, 4PB belonging to B. cibi and 2KB having 97% homology with B. marisflavi. Further evaluation of the selected endophytic isolates producing IAA is necessary to be carried out to explore their potency as a source of hormone to promote plant growth

Pengaruh Media terhadap Produksi Prodigiosin Isolat Bakteri Entomopatogen Serratia marcescens Asal Wereng Batang Cokelat

Prodigiosin, the red pigment producedby the bacterium Serratia marcescens, is a secondarymetabolite of the family tripyrrole that has been widely usedas an antibiotic in the multifunction treatment ofantibacterial as well as antifungal. This study was aimed tostudy the effect of Luria-Bertani (LB) broth and nutrientbroth (NB) media suplemented with several concentrationsof FeSO4 and CaCO3 on the production and characteristic ofprodigiosin derived from S. marcescens. The study wasarranged in a completely randomized factorial design withfour replications. The LB and NB media were supplementedwith 0, 2.5, 5, and 10 mM CaCO3 and 0, 0.25, 0.5, and 1 mMFeSO4. Results showed a red pigment produced by S.marcescens when cultured on both LB and NB media. Redlikepigmentation was varied when supplemented withdifferent concentration of Fe2+ and Ca2+. The higher theconcentration of Fe2+, the more intense the red color,conversely, the higher the concentration of Ca2+, the lighterthe red color. The interaction was found between the mediaand concentrations of CaCO3 and FeSO4 on the productionof prodigiosin. The highest prodigiosin production wasobtained on NB media supplemented with FeSO4.Meanwhile, the addition of CaCO3 did not affect theprodigiosin production. An addition of 1 mM FeSO4 to LBand NB media produced crude prodigiosin of 486.0 mg/mland 489.0 mg/ml, respectively. Based on purification bycolumn chromatography using silica gel, the prodigiosinproduction on LB and NB media was 378 mg/ml and 450mg/ml, with the purity level of 77.8% and 92%, respectively.Detection of prodigiosin by thin-layer chromatography usingsilica gel showed the red pigment had Rf value of 0.83 andbioautography assay showed there was an antibacterialactivity against Xanthomanas oryzae pv. oryzae

Pemurnian Parsial dan Karakterisasi Kitinase Asal Jamur Entomopatogen Beauveria bassiana Isolat BB200109

Beauveria bassiana is one of theentomopathogenic fungus that produces chitinase wheninfecting its host. This study was aimed to purify, isolate andcharacterize chitinase of B. bassiana isolate BB200109.Pathogen identity was determined both morphologically andmolecularly using ITS primer, whilst characterization wasdone at various conditions i.e. temperature, pH, metal ionand incubation time. Results showed that the BB200109isolate belonged to B. bassiana. The isolate producedextracellular chitinase with chitinolytic index of 1.035. Partialpurification of three saturated ammonium sulphateprecipitation (10, 30, and 70%) showed maximum purity of1.2 times, while dialysis could increase the purity of 1.9times compared to that of crude enzyme extract.Characterization results showed that the chitinase isolatedfrom B. bassiana isolate BB200109 had an optimum activityat pH 4, temperature 50oC, and optimum incubation time of90 minutes. The effect of metal ions (60 mM) Mn2+ served asactivator, while EDTA, K+, Mg2+, Cu2+, Fe2+, Zn2+, and Na+acted as inhibitors. The chitinase demonstrated loweraffinity to chitin substrate as indicated by high Km value of0.266 mg/l and a Vmax of 0.067 mg/l sec. Based on SDS-PAGE,chitinase from B. bassiana isolate BB200109 had molecularweight of 60.25 kDa. The study implied the potency ofB. bassiana isolate BB200109 as extracellular chitinaseproducer with its enzyme charateristics seems to bedeveloped as an insect biocontrol agent