Tangkahan Conservation Forest in Karo County, North Sumatera has high biodiversity of endemic herbs. Many species of the wild herbs are well known used as traditional medicine not only by local people but also by people out of the area. The methanol extract of the medicinal wild herbs in Tangkahan Conservation Forest, Karo County to relief skin diseases caused by bacteria and fungi never been studied medically. The antimicrobial activity leave extract of the medicinal herbs to pathogenic microorganisms are studied. The leaves extract of kembu-kembu (Callicarpa candicans), rintih bulung (Piper muricatum), cep-cepan (Castanopsis costata), and sereh kayu (Eugenia grandis), has antimicrobial to bacteria (Bacillus sp., Escherichia coli, Serratia marcescens, Staphylococcus aureus) and yeast (Candida albicans). Toxicity assay of these plants by brine shrimp method using Artemia salina indicates that cep-cepan dan sereh kayu have lethal concentration higher than kembu-kembu and rintih bulung.

Filamentous fungi were isolated from ten spices collected from markets in Indonesia. The aim was to enumerate fungal contamination and to determine the toxigenicity of Aspergillus flavus strains on each of the spices. Viable fungal populations were determined using a dilution method. Toxigenicity of Aspergillus flavus was determined by culture on a quick screening coconut agar and by PCR using four sets of primers specific for aflatoxin pathway genes. All the tested spices were contaminated by storage fungi, Species of Aspergillus was the most commonly isolated moulds followed by species of Fusarium, Mucor, Penicillium and Rhizopus. The greatest number of Aspergillus flavus isolates were found on white pepper, followed by nutmeg, cardamom, and black pepper. The greatest number of Aspergillus chevalieri isolates were found on coriander, followed by nutmeg. Fifty strains of A. flavus were isolated, all of the strains produced large sclerotia and biseriate conidiophores. Their toxigenicity was assayed by the presence of yellow pigment on a quick screening coconut agar medium and PCR amplification of regulatory and structural genes in the aflatoxin pathway.

The aim of this investigation was to determine the effect of various water activities (a w ) on fungal population in nutmeg kernels during storage. The seed nutmegs were obtained from ripe fruits one week after they fell on the ground in North Minahasa Regency, North Sulawesi Province, Indonesia. The kernels (moisture content ± 10%) were stored 0, 15, and 30 days in various a w (0.75, 0.80, 0.83, 0.90, 0.97) using saturated salt solutions at 29 °C in sorption containers. Serial dilution method followed by a pour-plate method in Dichloran 18% Glycerol Agar (DG18) was used to isolate and quantify the fungal population. Results revealed that kernels stored at a w p < 0.05) different from at a w = 0.80-0.83. Fungal population of kernels determined a w p by duration of storage. Range of a w 0.80-0.83 has a smaller total fungal population than a w Aspergillus and Eurotium (6 species), Penicillium (3 species), Fusarium (2 species), 1 species each of Cladosporium or Syncephalastrum, and isolate A. The largest total fungal population (5.0×10 5 CFU g -1 ) was present at the beginning of storage (a w = 0.97) and it was dominated by Penicillium citrinum (2.6×10 5 CFU g -1 ) followed by Cladosporium cladosporioides (1.7×10 5 CFU g -1 ). After 30 days of storage (a w = 0.97) the population of P. citrinum was still dominant with a population of 2.4×10 4 CFU g -1 . Eurotium chevalieri followed with a population of 1.2×10 4 CFU g -1 .

A study on the effectiveness of gamma irradiation at doses of 5 and 10 kGy on fungal population, Aspergillus flavus strains, and aflatoxin B1 contamination on stored nutmeg kernels was conducted. The kernels were collected from seeds in a period of one week from the ground at North Sulawesi Province, Indonesia. Dried shelled kernels with ± 10 % moisture content, packed in polyethylene bags at 2.1 kg/bag, were irradiated at 5 and 10 kGy and stored at ambient temperature (28 °C) for 2 and 4 months. Kernel moisture content, fungal population, and aflatoxin B1 were determined before and after irradiation, and after 2 and 4 months of storage. Results showed that fungal population was reduced with the increasing irradiation dose. Five species of fungi were isolated, i.e., Aspergillus flavus, A. niger, Cladosporium cladosporioides, Eurotium chevalieri, and Penicillium citrinum. A total of twelve A. flavus strains were isolated, five strains from unirradiated kernels and five and two strains from irradiated kernels at doses 5 and 10 kGy, respectively. Among these strains, 58 % were capable of producing L sclerotia and 25 % were identified as toxigenic. Kernel moisture during storage was 7.3 % and no aflatoxin B1 was detected before and after irradiation, and after 2 and 4 months of storage duration.

The aims of this work were to investigate the effects of gamma irradiation on population, viability and aflatoxin B production of strains isolated from nutmeg kernels. Thirteen strains of. were isolated and cultured in potato dextrose agar. Conidia were harvested, air-dried, and irradiated 0, 5, or 10 kGy with gamma rays using a Cobalt-60 source. Toxigenicity were determined using a coconut agar medium and thin layer chromatography. Genomes of strains were extracted from mycelia. Four sets of primers, regulatory () and structural genes (-, -, -) were used to confirm the presence of the genes. Our results indicate that total fungal populations decreased significantly ( < 0.05) with increasing irradiation dose. However, doses of 5 and 10 kGy were insufficient to completely eliminate the viability of some . strains. Irradiation did not change toxigenicity and triggered surviving toxigenic strains to produce aflatoxin B.

Air kelapa adalah senyawa alami kompleks yang sering digunakan sebagai pengatur tumbuh alami.   Penggunaan air kelapa sebagai bahan organik merupakan alternatif dari penggunaan bahan sintetis pada tanaman. Tujuan penelitian ini adalah untuk mengetahui pengaruh konsentrasi limbah dalam air kelapa dan air cucian beras serta lama perendaman terhadap perkecambahan biji kacang hijau. Parameter yang diamati adalah tinggi globul, jumlah radikula, dan panjang radikula. Berdasarkan hasil penelitian, air kelapa dan air cucian beras berpengaruh terhadap tinggi bulu dimana bulu tertinggi terdapat pada kombinasi (20 ml air kelapa + 80 ml air cucian beras dan perendaman 2 jam). Panjang radikula terpanjang ditemukan pada kombinasi (10 ml air kelapa + 90 ml air cucian beras dan perendaman 6 jam). Jumlah akar paling banyak terdapat pada kombinasi (50 ml air kelapa + 50 ml air cucian beras dan perendaman 6 jam).

Isolation of soil fungi from landfill in Medan, North Sumatera, Indonesia was conducted. The aim was to investigate the fungal that potential to decolorize waste liquid batik home industry. Results showed that twenty-three species of filamentous fungi were successfuly isolated. All of the isolates were cultured in minimum salt medium containing waste liquid batik at concentration 25, 50, and 75%. At 75% waste, only 4 fungal isolates (Ys02, Ys13, Ys14, and Ys21) showed growth response. Cultured of the fungal isolates in minimum salt medium with 25% waste + 0.5% glucose were found three fungal isolates (Ys02, Ys14, and Ys21). Whereas, medium with 25% waste with no glucose were found only two fungal isolates (Ys14, and Ys21).

Assay on ability of endophytic bacteria isolated from peanut to inhibit Sclerotium sp. growth in peanut seedlings.   A study on assay of ability of endophytic bacteria to inhibit Sclerotium sp. in peanut seedling has been done. The bacteria were isolated from peanut healthy plants, while Sclerotium sp. was isolated from infected peanaut plant. Antagonistic assay was conducted by dual culture method.  In vivo assay of inhibiting Sclerotium sp. was conducted by dipping peanut seed in bacterial solution, and planting the seed in soil:compost (3:1) growing media. Six endophytic bacterial isolates showed to inhibit the growth of Sclerotium sp. in vitro. LN1 seemed to inhibit more of Sclerotium sp., while LN5 showed to inhibit less. Two potential isolates LN1 of gram-negative and LN2 of gram-positive using for further study showed to decrease more of dumping off. It also seemed that the isolates increased the seedling height, number of leaves, and dry weight.