Academic literature on the topic 'Mushroom detection'

Terfezia pfeilii is an edible mycorrhizal fungus that thrives in the Kalahari Desert of southern Africa. It is best known by desert dwellers for its flavour and as a source of nutrition. Although the genus Terfezia is generally regarded as being an ectomycorrhizal mycobiont, the exact mycorrhizal type formed by T. pfeilli and its' associated host plants remains uncertain. Discovery of the host plants for T. pfeilii would first be required in order to further investigate the life cycle and cultivation of this truffle. This study focussed on the isolation of mycelia from the ascocarp, optimising the growth conditions of the mycelial cultures, rapid molecular identification of T. pfeilii, investigation of potential helper bacteria and mycorrhizal synthesis experiments. T. pfeilii ascocarps were harvested from the Spitskop Nature Reserve in Upington, South Africa. Ascocarps were successfully identified using both morphological and molecular methods. Despite the delayed growth mostly caused by contaminating microorganisms, the isolation of T. pfeilii mycelia culture was successful. Molecular techniques were used to confirm the identity of the pure culture. Further studies were conducted on ways to improve the growth conditions of the mycelial culture on Fontana medium. An optimum temperature of 32°C, the addition of Bovine Serum Albumin as a nitrogen source and a pH of 7.5 significantly improved the growth of T. pfeilii in vitro. A rapid PeR-based molecular method was developed to speed up the identification of T. pfeilii. Specific primers that can exclusively amplify the ITS region of T. pfeilii were designed and used to identify both the ascocarps and the mycelial culture. The specificity of these primers was confirmed by their inability to amplify DNA from the isolates of contamining fungi obtained during the isolation process. Molecular comparison was made to confirm the reclassification of South African samples of T. pfeilii as Kalaharituber pfeilii as proposed by Ferdman et al.,(2005). However, in this study, the name T. pfeilii has been retained. A total of 17 bacterial isolates were obtained from the fruiting bodies of T. pfeaii and these were tested for stimulation of mycelial growth in vitro, indole production and phosphate solubilising capabilities. Bacterial isolates that showed potential to be Mycorrhization Helper Bacteria (MHB) were identified as Paenibacillus sp., Bacillus sp. and Rhizobium tropici. Selected plant seedlings were inoculated with T. pfeilii cultures or ascocarp slurry in order to re-establish the mycorrhizal association. After 8 months, light microscopy observations revealed an endomycorrhizal type association between Cynodon dactylon and T. pfeilii. This was confirmed with molecular analysis using specific T. pfeilii ITS primers. After 15 months, molecular methods confirmed Acacia erioloba as another host plant. These results have provided essential information paving the way for further investigation into the life cycle and biology of the Kalahari truffle.<br>KMBT_363<br>Adobe Acrobat 9.53 Paper Capture Plug-in

The purpose of this thesis is to assemble an HPGe detector intended to be used in a mass experiment during the autumn of 2018. After assembly, the detector will be characterized and a shielding, consisting of approximately two tons of lead, will be assembled around the detector. Different modules will be tested to find the optimal energy resolution possible for the planned measurements. To characterize the detector several measurements will be taken at different measurement geometries. Measurements of the background radiations will be performed before and after the assembly of the lead shielding such that a comparison of the shielding's effect on measurements can be made. These measurements will also be analyzed in an attempt to identify the different radionuclides contributing to the background radiation. The result was a reliable set-up with a good energy resolution. However, more tests are required to gain a greater understanding of the inner structure of the detector.

碩士<br>國立中興大學<br>植物病理學系<br>91<br>In 1998, commercial cultivation of Pleurotus eryngii (Dc. : Fr.)Quēl. at Taiwan Agricultural Research Institute (TARI) and Wufeng areas around central Taiwan were severely affected by an unknown disease. Symptoms consisted of brown spot, curling of the tissues, sometimes even shrinking and cracking of the infected fruit bodies. Ten isolates, GR-6、GR-7、GR-12、GR-13、GR-16、GR-18、GR-23、GR-28、GR-31 and GR-37 were isolated from diseased fruiting bodies. Pathogenicity was confirmed by inoculating the fungus onto fruit-bodies of P. eryngii for 3 - 4 days under high humidity (RH＞93%) at 16℃. Discoloration of brown spot similar to the original symptoms developed only on inoculated king oyster mushrooms. Noninoculated king oyster mushrooms P. eryngii remained symptomless. On malt extract peptone agar, colony diameter reached 32.5-35.0 mm 10 days after inoculation at 20℃, appeared to be orange to salmon red. Mycelium with septa, two kinds of conidiophores, one consists of verticillate conidiophores 110-170 µm, bearing 2-6 whorls of phialides 13-28 µm; the other bearing the “densely penicillate” phialides 10-16 µm ; Conidia hyaline, one-celled, ovoid , accumulating in a single, slimy, base protruding, smooth-walled, 4.0-6.8 x 3.0-4.5 µm. The fungus was identified as Gliocladium roseum Bainier according to the references of Domsch, et al (1980)、Schroer, et al (1999) and Smalley ＆ Hansen (1957). In advance, the causal agent was also confirmed by comparing the ITS and 28S rDNA sequences of ten isolates of the pathogen with NCBI database. The optimum temperature for conidial germination and mycelial growth of G. roseum isolates GR-12 and GR-28 was at 24-28℃. The best temperature for infection of G. roseum isolates GR-12 and GR-28 onto fruit-bodies of oyster mushroom P. eryngii was at 24-28℃. Pathogenicity of G. roseum isolates GR-12 and GR-28 was confirmed by inoculating onto fruit-bodies of Agaricus bisporus (Lange) Imbach、Lentinus edodes (Berk.) Sing.、Flammulina velutipes (Curt.: Fr.) Sing.、Pleurotus sajor (Fr.) Sing.、Pleurotus cystidosus Miller、Agrocybe cylindracea (DC: Fr) Mre.、Hypsizigus marmoreus Bunashimeji、Coprinus comatus (Müll.: Fr. ) Pers. Twelve carbohydrates and twelve nitrogenous compounds were evaluated for their effects on mycelial growth of two isolates, GR-12 and GR-28 of the pathogen. Among those compounds, sucrose, sorbitol, starch and maltose were more effective than other carbohydrates to enhance the growth of G. roseum. As to nitrogenous compounds, NaNO3, NaNO2 and KNO3 were more effective to enhance growth of the pathogen. Seven pesticides were respectively added into the basal medium (a modified Czapek’s medium containing 3% (w/v) maltose and 0.2% (w/v) NaNO2 , MNa medium) for indexing their suppressive effectiveness. Flutolanil at 200 ppm, mertect at 4 ppm, streptomycin sulfate at 500 ppm, chloramphenicol at 500 ppm and penicillin G at 500 ppm were obviously not effective in inhibiting growth of the pathogen. Finally, maltose-NaNO2 semiselective medium (MNa semiselective medium) consisting of 30 g maltose, 2 g NaNO2, 1 g K2HPO4, 0.5 g MgSO4 7H2O, 0.5 g KCl, 0.01 g FeSO4 7H2O, 20 g agar, 200 ppm flutolanil, 4 ppm mertect, 200 ppm streptomycin sulfate, 200 ppm chloramphenicol, 200 ppm penicillin G and 1L distilled water was hence formulated for the enumeration and isolation of G. roseum from the infested sawdust. The results showed that G. roseum could be accurately detected from artificially and naturally infested sawdust by use of MNa semiselective medium. Population density of the pathogen in naturally infested sawdust was 0 - 1.0×102cfu/g sawdust and in naturally infested soil was 0 — 3.0×102cfu/g soil. High population density of the fungus was also detected from air filter of the mushroom cultivation room by MNa semiselective medium. The disease severity could be reduced more than 30% by spraying Streptomyces padanus PMS-702 at 104cfu/ml, Bacillus subtilis BS 6-14 at 105cfu/ml or CH100 at 2000-fold dilution at the same time or one day before inoculation with the pathogen onto the fruit-bodies of P. eryngii. Environmental hygiene of the mushroom cultivation room is the determinant factor for the disease control. The study indicated that washing air filter of the mushroom cultivation room with water or 2%(v/v) sodium hypochlorite was effective in reducing population density of the pathogen for the disease control.