{"created":"2023-06-19T07:19:21.724907+00:00","id":5416,"links":{},"metadata":{"_buckets":{"deposit":"daab05c9-9fcd-480c-8328-65d71753a920"},"_deposit":{"created_by":4,"id":"5416","owners":[4],"pid":{"revision_id":0,"type":"depid","value":"5416"},"status":"published"},"_oai":{"id":"oai:az.repo.nii.ac.jp:00005416","sets":["370:197:377"]},"author_link":["23113","23114"],"item_10006_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2021-03-15"}]},"item_10006_degree_grantor_9":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"麻布大学"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"32701","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_10006_degree_name_8":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士(学術）"}]},"item_10006_description_22":{"attribute_name":"Abstract","attribute_value_mlt":[{"subitem_description":"Liposcelis bostrychophila (booklice) are a representative species of indoor psocids that are commonly found in ordinary houses and environments such as food-related facilities and pharmaceutical factories. As pests that affect preserved foods all over the world, they cause serious food hygiene problems because they prefer to live in preserved foods and grains. Booklice are 1.0 to 1.3 mm in body length and are a type of psocid with no wings, even upon reaching adulthood. Furthermore, they reproduce parthenogenetically with only females; as a single booklouse lays approximately 110 eggs in her lifetime, they have an extremely high breeding capacity. They can survive for up to two months without food and can become established in indoor environments within a short period of time. Although they are omnivorous, it has been reported that they particularly prefer brewer’s yeast and fungi. There are many cases of huge outbreak of fungivorous psocids, such as booklice, occurring in fungi that have propagated in institutional environments, such as food-related facilities and pharmaceutical factories, leading to the spread of fungi in the environment via body surfaces and feces. Because the number of psocids inhabiting the environment also increases, as the propagation of fungi increases in the facility, these psocids are indicators of fungal development. Since booklice are resistant to various insecticides and difficult to control, basic measures include preventing outbreaks of psocids by preventing the development of fungi in the facility. Although an understanding of the types of fungi strongly preferred by these pests is important for preventing outbreaks of psocids, there have been no studies on the fungal preferences of booklice or of the characteristics of fungi that are strongly preferred. Integrated pest management (IPM), which is a control method that integrates physical and environmental measures, has recently gained attention as an effective means of controlling insecticide-resistant insects, such as booklice. The basis of IPM involves monitoring the outbreak of the target pests and taking appropriate measures at an early stage. Effective substances and means for attracting pests are required to effectively carry out the monitoring. Various studies have been conducted on attractants using ultraviolet rays and bait in order to develop traps that can effectively capture booklice. However, to our knowledge, no studies have determined the factors related to these insects’ preferences and applied them to attraction using fungi of high feeding preference as a model. \nTherefore, in the present study, we evaluated the feeding preferences of booklice concerning typical fungi found in food-related facilities and investigated the morphological, optical, and biochemical profiles of the highly preferred fungi as well as factors, such as odorous substances, produced by these fungi and their relationship to the preference. The study outline is shown below.\n\nⅠ. The evaluation of fungal feeding preferences\nA booklouse feeding preference test was conducted using four species of fungi collected from an indoor environment, namely Aspergillus tubingensis, Aspergillus flavus, Penicillium chrysogenum, and Cladosporium cladosporioide. Paper discs (fungus discs) of 8 mm in diameter on which the test fungi were grown were placed at equal intervals in a plastic case 9 cm in diameter. Thirty adult booklice were released from the center of the case, and then the device was stored in an incubator set at 27±1 °C (humidity ≥80%). The population gathered on each disc was counted daily on the 2nd to 4th days of storage, and then the total population across 3 days was compared among discs (n=10). \nAmong the test fungi, the booklice showed the highest preference for P. chrysogenum, followed by C. cladosporioides and A. tubingensis, in order, with A. flavus being shown the lowest preference. Although the hyphae and spores on the discs of P. chrysogenum and C. cladosporioides were eaten, leaving few remaining fungus bodies, the fungus bodies of A. tubingensis and A. flavus were not eaten. These findings indicate that the booklice showed different feeding preferences among fungi, with the highest preference shown for P. chrysogenum.\n\nII. Morphological, optical, and biochemical profiles of fungi, in relation to feeding preference\nThe morphological, optical, and biochemical profiles of P. chrysogenum, which was shown the highest preference in the preference evaluation test, were compared with the other three tested species of fungi in order to identify the characteristics of the fungi that determined the feeding behavior and preferences among booklice. \nFirst, concerning the morphological profiles, we magnified and observed the surface characteristics and height of the fungal colonies, along with the shape and size of the spores and the thickness of the hyphae. The colony surface of P. chrysogenum and C. cladosporioides were found to be smooth and velvety with densely grown hyphae, whereas the surfaces of A. tubingensis and A. flavus colonies were uneven, and the hyphal density was coarse and powdery. The heights of the colonies of P. chrysogenum and C. cladosporioides were 200 µm, while A. flavus was 400 µm, and A. tubingensis was 1,000 µm, indicating a large difference in height. When booklice ate the fungus, they bent their legs and lowered their trophi to the position of the fungus, then peeled the fungus bodies off with their jaws. The height of the booklice was 300 to 400 µm, the trophi were located on the underside of the head, and because the thrusting range of the neck is small, the body structure was such that it was easy to eat food at a position lower than the trophi. The heights of the colonies of P. chrysogenum and C. cladosporioides were lower than the height of the booklice. In addition, because the hyphae and spores grew densely at a position lower than the trophi of booklice, it was easy for them to eat these fungus bodies. Based on these results, the behavior of booklice while eating fungi was clarified. To our knowledge, this is the first report on the details of this feeding behavior. These findings indicate that booklice prefer velvety fungi, such as P. chrysogenum and C. cladosporioides, with a low colony height.\nNext, upon observing the fungi under UV irradiation (330–385 nm), while the hyphae of A. tubingensis and A. flavus emitted light, the hyphae of P. chrysogenum and C. cladosporioides, which had been shown to have a high feeding preference, did not emit light, suggesting that the fungi that did not emit light had higher preference. \nFurthermore, the pH of the fungus disc of A. tubingensis was 3.1, while those of other test fungi, including P. chrysogenum, ranged from 5.2–6.6, indicating that A. tubingensis was acidic. It was thus assumed that A. tubingensis, which has hyphae that are taller than the body height of booklice, was used as a hiding place, rather than for feeding, as the fungal bodies of the disc remained uneaten despite A. tubingensis being the second-most preferred fungus in the preference evaluation test.\n\nIII. The evaluation of preference by odor of fungi and identification of odorous substances\nThe preference of the odorous substances produced by the fungi was evaluated using a handmade olfactometer device. The device consisted of a central box and four chambers, with four species of fungus discs placed in each chamber, and the air was adjusted to flow from each chamber side toward the central box. One hundred and twenty adult booklice were released from the central box, and the device was stored in an incubator set at 27±1 °C (humidity ≥80%). The population in each chamber was measured on the 3rd day of storage (n=5). As the result, the largest population was confirmed in the chamber in which the fungus disc of P. chrysogenum had been placed, followed by C. cladosporioides and A. flavus, in order, with A. tubingensis having attracted the fewest booklice. Similar to the results of the feeding preference evaluation, the booklice showed a high preference for P. chrysogenum in the odor evaluation test, suggesting the production of odorous substances that induced feeding behavior among booklice.\nNext, to identify the odorous substances produced by P. chrysogenum, the odorous substances of each fungus disc were measured by GC/MS, and as a result, 35 types of odorous substances were detected. Nine substances were detected in P. chrysogenum, which had the highest palatability (styrene, 1,5-octadien-3-ol, 1-octen-3-ol, 3-octanone, 4-methylundecane, 2,6,10-trimethyldodecane, 3,3,4-trimethyldecane, 3,4,5,6-tetramethyloctane, and butylated hydroxytoluene). Among these, 1,5-octadien-3-ol and 2,6,10-trimethyldodecane were detected only in P. chrysogenum, suggesting that these odorants are candidate booklice attractants.\nAs indicated above, this study revealed that preferences by booklice differ among species of fungus, given the results of the fungal feeding preference test of booklice, with P. chrysogenum being the most preferred among the four species of fungi commonly found in food-related facilities. We also examined the characteristics of fungi highly preferred by booklice in order to identify the fungal factors that determine feeding preference. Fungi that are highly preferred by booklice form velvety colonies that grow densely at a position lower than the trophi, and their hyphae do not emit light under ultraviolet irradiation. Furthermore, these fungi are believed to produce specific odorous substances that booklice can detect, allowing them to find their preferred food more easily.\nThese results indicate that controlling psocids will require understanding the species of fungi that are associated with a high risk of psocid breeding, which is problematic in many facilities, including food factories, food storage facilities, and pharmaceutical factories. Monitoring these fungi can predict the risk of psocid occurrence at an early stage. Furthermore, the proactive removal of such high-risk fungi present in institutional environments may lead to the prevention of outbreaks of fungivorous pests, such as psocids. Determining the common properties of highly preferred fungi, such as the specific odorous substances produced by the fungi that were revealed in this study, can be used to improve the efficiency of monitoring of psocids and help develop attractants to capture these pests. This may lead to the development of integrated pest management methods for psocids, which are currently being studied worldwide."}]},"item_10006_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"ヒラタチャタテは屋内性チャタテムシの代表種であり、一般家屋だけでなく、食品関連施設や製薬工場などの環境に普通に見られる。また、保存された食品や穀物に好んで生息するため、世界中で保存食品の害虫として、食品衛生上深刻な問題を引き起こしている。ヒラタチャタテは体長1.0〜1.3 mmで、成虫になっても翅がないタイプのチャタテムシである。また、雌のみで単為生殖し、生涯で約110個の卵を産むため、非常に高い繁殖能力を持っている。さらに、食物がなくても最大2ヵ月間生存可能で、屋内環境でも短期間で定着できる。食性は雑食性であるが、特にビール酵母や糸状菌を好むことが報告されている。食品関連施設や製薬工場などの施設環境に繁殖した糸状菌にヒラタチャタテなどの食菌性チャタテムシが大量発生し、体表や糞を介して環境に糸状菌を拡散させる事例が非常に多い。したがって、施設内に繁殖した糸状菌が増加すると、環境に生息するチャタテムシの数も増加するため、これらのチャタテムシは糸状菌の繁殖の指標となっている。また、ヒラタチャタテは多種の殺虫剤に耐性を持ち、その防除が困難となるため、施設内の糸状菌の繁殖を防いで、チャタテムシの発生を予防する対策が基本となる。チャタテムシの発生予防には、嗜好性が高い糸状菌の種類を理解することが重要であるが、ヒラタチャタテの糸状菌の嗜好性や、嗜好性が高い糸状菌の特性に関する研究はみられない。一方で、ヒラタチャタテなどの殺虫剤抵抗性昆虫を防除するための効果的な手段として、物理的対策や環境的対策などを統合した防除手法である総合的害虫管理（Integrated Pest Management, IPM）が最近注目されている。IPMの基本は、対象となる害虫の発生状況をモニタリングし、適切な対策を早期に行うことであり、このモニタリングを効果的に行うためには、害虫を誘引する有効な物質や手段が求められる。これまでもヒラタチャタテを効果的に捕獲できるトラップを開発するために、紫外線や餌を使った誘引剤について様々な研究がなされてきたが、摂食嗜好性が高い糸状菌をモデルとして、その嗜好性に関する要因を多角的に解明し、誘引へ応用した研究はみられない。\n　そこで、本研究では食品関連施設で見られる代表的な糸状菌を対象に、ヒラタチャタテの摂食嗜好性を評価し、嗜好性の高い糸状菌の形態的特性、光学的特性、生化学的特性、糸状菌によって産生される臭気物質などの要因とそれらの関連性について検討した。本研究の概要は以下のとおりである。\n\nⅠ. 糸状菌に対する摂食嗜好性評価\n　室内環境から採取した4種の糸状菌、すなわちAspergillus tubingensis、Aspergillus flavus、Penicillium chrysogenum、Cladosporium cladosporioidesを供試菌として、ヒラタチャタテの摂食嗜好性試験を行った。供試菌を発育させた直径8 ㎜ペーパーディスク（糸状菌ディスク）を直径9 cmのプラスチックケースに等間隔で配置し、成虫30頭をケース中央から放虫した後、装置を27±1℃（湿度80％以上）に設定したインキュベーターに保管した。保管後2～4日目に各ディスク上に集まった個体数を毎日計測し、3日間の合計数を比較した（n=10）。その結果、供試菌のなかで、最も嗜好性の高かった糸状菌はP. chrysogenumであった。次いで、C. cladosporioides、A. tubingensisと続き、A. flavusの嗜好性が最も低かった。また、P. chrysogenumとC. cladosporioidesのディスク上の菌糸や胞子は摂食され、菌体はほとんど残っていなかったが、A. tubingensisとA. flavusの菌体は摂食されていなかった。これらの結果から、ヒラタチャタテは糸状菌の種類によって異なる摂食嗜好性を示すことが明らかとなり、P. chrysogenumの嗜好性が最も高いことが判明した。\n\nⅡ. 摂食嗜好性に関わる糸状菌の形態的、光学的および生化学的特性\n　嗜好性評価試験において最も嗜好性が高かったP. chrysogenumの形態的、光学的、生化学的特性について、供試菌の他3種と比較し、ヒラタチャタテの摂食行動と、嗜好性を決定する糸状菌の特性との関連性を調べた。まず、形態的特性について、糸状菌コロニーの表面特性および高さ、胞子の形状およびサイズ、菌糸の太さを拡大観察した結果、P. chrysogenumとC. cladosporioidesのコロニー表面は滑らかで、菌糸が密に発育したビロード状であった。一方、A. tubingensisとA. flavusのコロニー表面は不均一で、菌糸の密度が粗い粉状であった。P. chrysogenumとC. cladosporioidesのコロニーの高さは200 µm、A. flavusは400 µm、A. tubingensisは1,000 µmであり、高さに大きな差が見られた。ヒラタチャタテは、糸状菌の摂食時に、脚を曲げ、口器を糸状菌の位置まで下げて菌体を顎で剥し取っていた。ヒラタチャタテの体高は300～400 µmで、口器は頭部の下面に位置し、頸部の駆動域が小さいため、口器よりも低い位置の餌を摂食しやすい体の構造となっていた。P. chrysogenumおよびC. cladosporioidesのコロニーの高さは、ヒラタチャタテの体高よりも低かった。また、菌糸と胞子は、ヒラタチャタテの口器よりも低い位置で密集して発育していたため、これらの菌体を容易に食べることができた。これらの結果より、ヒラタチャタテの糸状菌摂食時の行動が明らかとなり、この摂食行動の詳細については世界で初めての報告である。さらに、ヒラタチャタテは、コロニーの高さが低いビロード状の糸状菌であるP. chrysogenumおよびC. cladosporioidesを餌として好むことが判明した。\n　次に、糸状菌をUV照射（330～385 nm）下で観察した結果、A. tubingensisとA. flavusの菌糸は発光したが、摂食嗜好性の高いP. chrysogenum、C. cladosporioidesの菌糸は発光せず、発光しない糸状菌の方が、嗜好性が高いことが示唆された。さらに、糸状菌ディスクのpHを測定した結果、P. chrysogenumを含む他の供試菌は5.2～6.6であったが、A. tubingensisは3.1と酸性を示した。A. tubingensisは嗜好性評価試験においては、2番目に嗜好性が高かったが、ディスクの菌体は摂食されずに残っていたことから、糸状菌を餌としてではなく、虫体よりも高い菌糸のコロニーを潜伏場所としていたことが推察された。\n\nⅢ. 糸状菌の臭気による嗜好性評価および臭気物質の同定\n　糸状菌が産生する臭気物質による嗜好性について、自作の嗅覚誘引装置を用いて評価を行った。装置は中央ボックスと4つのチャンバーで構成され、各チャンバーに4種の糸状菌ディスクを配置し、中央ボックスに向かって、各チャンバー側から空気が流れるように調整した。成虫120頭を中央ボックスから放虫し、装置を27±1℃（湿度80％以上）に設定したインキュベーターに保管した。保管後3日目に各チャンバー内の個体数を計測した（n=5）。その結果、P. chrysogenumの糸状菌ディスクを置いたチャンバーで最も多くの個体数が確認された。次いで、C. cladosporioides、A. flavusが多く、A. tubeingensisは誘引された個体数が最も少なかった。摂食嗜好性評価の結果と同様に、臭気による評価試験においてもP. chrysogenumが高い嗜好性を示し、ヒラタチャタテの摂食行動を誘発させる臭気物質の産生が示唆された。\n　そこで、P. chrysogenumが産生した臭気物質を同定するため、各糸状菌ディスクの臭気物質をGC/MSで測定した結果、35種類の臭気物質が検出された。嗜好性が最も高かったP. chrysogenumから検出された物質は9種類（styrene、1,5-octadien-3-ol、1-octen-3-ol、3-octanone、4-methylundecane、2,6,10-trimethyldodecane、3,3,4-trimethyldecane、3,4,5,6-tetramethyloctane、butylated hydroxy toluene）であり、このうち1,5-octadien-3-olと2,6,10-trimethyldodecaneは、P. chrysogenum のみから検出された。したがって、これらの臭気物質がヒラタチャタテの誘引物質の候補であることが示唆された。\n\n　このように、本研究では、ヒラタチャタテの糸状菌の摂食嗜好性試験の結果により、糸状菌の種類によって嗜好性が異なり、食品関連施設で一般的に見られる4種の糸状菌の中では、P. chrysogenumが最も嗜好性が高いことが明らかになった。また、ヒラタチャタテの嗜好性が高い糸状菌の特性との関連性を検討し、摂食嗜好性を決定する糸状菌に共通する要因を特定した。すなわち、ヒラタチャタテにとって嗜好性の高い糸状菌は、口器よりも低い位置で密集して発育するビロード状のコロニーを形成し、また紫外線照射下で菌糸は発光しない種類であった。さらに、これらの糸状菌は特定の臭気物質を産生し、ヒラタチャタテは摂食嗜好性の高い糸状菌の臭気を探知できるものと考えられた。\n　これらの結果により、食品工場や食品貯蔵施設、製薬工場など多くの施設で問題となっているチャタテムシの防除において、チャタテムシの繁殖リスクが高い糸状菌の種類を把握することの有効性が示された。また、こうした糸状菌をモニタリングすることにより、チャタテムシの発生リスクを早期に予測することができる。さらに、施設環境に存在するリスクの高い糸状菌を積極的に除去することができれば、チャタテムシをはじめとする食菌性害虫の発生予防につながると考えられた。一方で、本研究で明らかになった糸状菌が産生する特定の臭気物質など、嗜好性の高い糸状菌がもつ共通の特性は、チャタテムシの効率的なモニタリングおよび捕獲に必要な誘引剤の開発などに応用が可能であり、世界的に検討が進められているチャタテムシに対する総合的有害生物防除（IPM）の手法の発展につながると考えられた。"}]},"item_10006_dissertation_number_12":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第35号"}]},"item_10006_textarea_23":{"attribute_name":"Rights","attribute_value_mlt":[{"subitem_textarea_value":"本論文の一部は以下のとおり公表されている。(Part of this dissertation has been published as follows.)\nYoshinami, M., Machida, R., Kobayashi, N., Sugita-Konishi, Y., Furuhata, K.\nMultifaceted fungal characteristics determining the fungal feeding preferences of the psocid, Liposcelis bostrychophila Badonnel (Psocoptera : Liposcelidae).\nJournal of Stored Products Research, 2020, 88, 101659\nhttps://doi.org/10.1016/j.jspr.2020.101659"}]},"item_10006_version_type_18":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"吉浪, 誠"}],"nameIdentifiers":[{}]},{"creatorNames":[{"creatorName":"Yoshinami, 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