Volatile metabolites of Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno and their toxicity to brinjal mealybug Coccidohystrix insolita (G)

Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno is a versatile indigenous entomopathogenic fungus with high speed of kill on hemipteran insects. Investigations were carried out to explore the volatile metabolites of L. saksenae and bioefficacy of its crude toxin to different life stages of brinjal mealybug, Coccidohystrix insolita. GCMS spectrum of crude toxin extracted from cultures grown in potato dextrose broth and Czapak Dox medium revealed the presence of 25 compounds each. The major secondary metabolites identified were 2,6 pyridine dicarboxylic acid (dipicolinic acid), n-hexadecanoic acid, octadecanoic acid, harmine, dl- mevalonic acid lactone, 2-piperidinone, 4H-pyran-4-one 2,3-dihydro-3,5dihydroxy-6methyl, acetamide,N-(2-phenylethyl), pyrrolo [1,2-a] pyrazine-1,4-dione, hexahydro. The biological properties of these compounds include insecticidal to nematicidal and antimicrobial activities. Bioefficacy studies with crude toxins revealed the toxicity of secondary metabolities to C. insolita. The dose dependent bioassay revealed 100 per cent moratality at a higher concentration of 1000 ppm at 72 and 96 h after treatment on nymphs and adults respectively. Results highlighted the role of secondary metabolites in the pathogenicity of saksenae and pave way to the utilization of its biocide molecules in safer pest management.

Perkembangan Penyakit Diplodia pada Tiga Isolat Botryodiplodia theobromae Path dan Peran Toksin Dalam Menekan Penyakit pada Jeruk (Citrus spp.)

<p>Penyakit diplodia (Botryodiplodia theobromae) pada tanaman jeruk menyebar cukup luas di sentra jeruk Indonesia. Serangan parah penyakit dapat menyebabkan kematian apabila tidak dikendalikan. Tujuan penelitian adalah mengetahui patogenisitas dan peran toksin dari tiga isolat B. theobromae asal Pasuruan dan Magetan pada jeruk siam, pamelo, dan manis. Penelitian dilakukan di Laboratorium dan Rumah Kasa Balai Penelitian Tanaman Jeruk dan Buah Subtropika pada bulan November 2015 – Mei 2016. Penelitian terdiri atas dua percobaan, yaitu uji patogenisitas pada tanaman dan uji toksin kasar pada skala laboratorium. Uji patogenisitas menggunakan rancangan acak kelompok dengan sembilan kombinasi perlakuan terdiri atas tiga jenis isolat, yaitu Mg52A.1, dan Mg39.2 (asal Magetan), Ps8b (asal Pasuruan), serta tiga jenis tanaman jeruk (pamelo, siam, manis). Parameter pengamatan terdiri atas masa inkubasi, jumlah sampel nekrosis, dan luas gejala. Perlakuan pengujian toksin terdiri atas kontrol tanpa toksin, toksin kasar isolat Mg52A.1, toksin kasar isolat Mg39.2, dan toksin kasar isolat Ps8b. Aplikasi toksin dilakukan pada daun tiga varietas jeruk dengan rancangan acak lengkap, tiap perlakuan diulang tiga kali dan masing masing terdiri atas dua daun asal tanaman yang berbeda. Hasil penelitian menunjukkan bahwa masa inkubasi isolat Mg39.2 lebih cepat dibandingkan dengan isolat Mg52A.1 dan Ps8b. Ketiga isolat patogen B. theobromae asal Pasuruan dan Magetan memiliki patogenisitas yang sama dalam menimbulkan gejala penyakit pada jeruk pamelo, siam, dan manis, sedangkan toksin hanya berperan dalam mempercepat masa inkubasi.</p><p>Diplodia disease (Botryodiplodia theobromae) spread quite widely in Indonesia citrus center. Severe attacks of disease can cause death if it not controlled. The purpose of this study was determine the pathogenicity and the effect of toxins from three isolates of B. theobromae origin Pasuruan and Magetan on tangerine, pummelo, and sweet orange varieties. The study was conducted at Indonesian Citrus and Subtropical Research Institute during November 2015 – May 2016. This observation consisted of two experiments that pathogenicity test in screenhouse and crude toxin of patogen test in laboratory. Pathogenicity test used randomized block design arranged as factorial. The first factor was three isolates: Mg52A.1, Mg39.2 (from Magetan), Ps8b (from Pasuruan) and the second factor were kind of citrus (pummelo, tangerine , and sweet orange). The observation parameter consist of the incubation period, the number of necrotic samples and visual symptom. Crude toxin test treatment consists of a control test toxin without toxins, crude toxin Mg52A.1, crude toxin Mg39.2 toxin, crude toxin Ps8b. Application toxin carried out on the three leaf varieties of oranges. Each treatment was repeated three times and each consists of two leaves of different varieties. The results showed that the incubation period Mg39.2 isolates faster than two other isolates. Infection with different isolates and treatment of different citrus varieties shows that it did not different significantly in causing disease symptom of diplodia. Similarly result on crude toxin treatment with three isolates on three varieties showed that it were not different necrotic symptom. Thus the three isolates of pathogens B.theobromae origin from Pasuruan and Magetan have the same pathogenicity in causing disease symptoms in citrus pummelo, tangerine, and sweet orange. Toxin only play a role in accelerating the incubation period.</p>

Detection of Toxic Effects of Clostridial Crude Toxin in Experimental Rats

The present study was conducted for the detection of toxic effects of clostridial crude toxin in experimental rats. The crude toxin of Clostridium perfringens was prepared and the rats were injected intraperitoneally (IP) 0.5 ml, 1.0 ml and 2.0 ml of crude toxin. The rats were observed for 24 hrs. The crude toxin inoculated rats showed the dose dependent clinical signs; depression, rough hair coat, respiratory distress, diarrhea and rapid heart beats, whereas PBS inoculated rats did not show any clinical sings. Necropsy changes were variable however, highly dilated and distended whole intestine with blood stained semifluid contents and gas along with congestion in all the affected rats were found dose dependently. Liver, lung and kidney were congested, hemorrhagic and swollen. More or less hydrothorax was seen during the postmortem of all affected rats. The peritoneal fat was frequently congested in all affected rats. Histopathological changes in intestine (0.5 ml inoculated rats) involved congestion, slightly swollen goblet cells and hemorrhages. The most severe lesions comprised of profuse hemorrhages in the mucosa and submucosa with complete necrosis, desquamation and intense leukocytic infiltration in 2 ml inoculated rats. Affected liver (1 ml inoculated rats) exhibited engorgement of central veins, sinusoidal spaces with blood and fatty change. The hepatocytes revealed swelling, granulation and vacuolation of cell cytoplasm, extensive hemorrhage and congestion were seen in 2 ml toxin inoculated rats. Congestion and sometimes extravasation were observed in the subepicardial region of heart. The myocardium revealed mild degenerative changes in the form of granularity of myocardial fiber. In lungs there was congestion, hemorrhage and leukocytes infiltration in the interstitial spaces around the bronchioles in both 1 and 2 ml toxin inoculated rats. Affected kidneys of different doses of crude toxin showed hemorrhage, congestion and inflammatory cells dose dependently. From the above findings, it may be concluded that clostridial crude toxin induced clinical signs, gross and histopathological lesions dose dependently in experimental rats.DOI: http://dx.doi.org/10.3329/pa.v21i1-2.16753 Progress. Agric. 21(1 & 2): 65 - 72, 2010

Inhibition of bacteria contaminating alcoholic fermentations by killer yeasts

The aim of this work was to study the in vitro antibacterial activity possessed by killer yeast strains against bacteria contaminating alcoholic fermentation (Bacillus subtilis, Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides), in cell X cell and cell X crude toxin preparations. The bacteria were not inhibited by any S. cerevisiae killer strains (5 out of 11). The inhibition caused by two crude toxin preparations (Trichosporon figueirae and Candida sp) against L. plantarum was surprisingly high but not in the same extent for B. subtilis, especially with three killer strains (Candida glabrata, Pichia anomala and Candida sp). L. mesenteroides and L. fermentum strains were neither inhibited in cell X cell nor crude toxin X cell tests. The results suggested that killer activity of yeasts might operate over bacteria and it could be used for the biocontrol of contaminating bacteria from alcoholic fermentation if additional tests on toxin application in fermentation shown to be successful. A wider panel of S. cerevisiae killer strains should be used to confirm that they were really unable to control the growth of these Gram-positive bacteria.

PERANAN TOKSIN YANG DIHASILKAN OLEH BOTRYODIPLODIA THEOBROMAE DALAM MENIMBULKAN PENYAKIT DIPLODIA PADA BEBERAPA JENIS JERUK

Role of toxin produced by Botryodiplodia theobromae causes Diplodia Bark Diseases on some citrus. The purpose of the research was to study the role of toxin produced by Botryodiplodia theobromae causes diplodia bark diseases on some citrus. Research was conducted from March through November 2007. The experiment was done at the laboratory and at a glass house of the Department of Plant Pests and Diseases of the Faculty of Agriculture and the laboratory of the Faculty of Science and Mathematics Lambung Mangkurat University in Banjarbaru. For a leaf-necrosis bioassay of crude toxin production, the surfaces of the leaves were scratched near the center with a needle, and culture filtrate samples (50 µl) were placed on each wounded site. Treated leaves were incubated in a moist chamber with light at 26oC for 4 days, and toxin activity was determined by induction of veinal necrosis on the seven susceptible cultivar of citrus. The results of the experiment showed that the B. theobromae pathogens produced the toxin. The crude toxin was bioassayed for leaf necrosis to determine their ability to produce toxin. Culture filtrates of the isolate were highly toxic only on five susceptible citrus leaves siam Banjar citrus, sweet orange, lime, kaffir lime, and sour lime, indicating that the B. theobromae can produced toxin. Pathogenicity and toxin production of B. theobromae did not differ among different cultivar. While, no necrotic symptom produces on the pummelo and sunkist. Toxin production of B. theobromae produced during spore germination.