Multidendritic sensory neurons in the adult Drosophila abdomen: origins, dendritic morphology, and segment- and age-dependent programmed cell death

<p>Abstract</p> <p>Background</p> <p>For the establishment of functional neural circuits that support a wide range of animal behaviors, initial circuits formed in early development have to be reorganized. One way to achieve this is local remodeling of the circuitry hardwiring. To genetically investigate the underlying mechanisms of this remodeling, one model system employs a major group of <it>Drosophila </it>multidendritic sensory neurons - the dendritic arborization (da) neurons - which exhibit dramatic dendritic pruning and subsequent growth during metamorphosis. The 15 da neurons are identified in each larval abdominal hemisegment and are classified into four categories - classes I to IV - in order of increasing size of their receptive fields and/or arbor complexity at the mature larval stage. Our knowledge regarding the anatomy and developmental basis of adult da neurons is still fragmentary.</p> <p>Results</p> <p>We identified multidendritic neurons in the adult <it>Drosophila </it>abdomen, visualized the dendritic arbors of the individual neurons, and traced the origins of those cells back to the larval stage. There were six da neurons in abdominal hemisegment 3 or 4 (A3/4) of the pharate adult and the adult just after eclosion, five of which were persistent larval da neurons. We quantitatively analyzed dendritic arbors of three of the six adult neurons and examined expression in the pharate adult of key transcription factors that result in the larval class-selective dendritic morphologies. The 'baseline design' of A3/4 in the adult was further modified in a segment-dependent and age-dependent manner. One of our notable findings is that a larval class I neuron, ddaE, completed dendritic remodeling in A2 to A4 and then underwent caspase-dependent cell death within 1 week after eclosion, while homologous neurons in A5 and in more posterior segments degenerated at pupal stages. Another finding is that the dendritic arbor of a class IV neuron, v'ada, was immediately reshaped during post-eclosion growth. It exhibited prominent radial-to-lattice transformation in 1-day-old adults, and the resultant lattice-shaped arbor persisted throughout adult life.</p> <p>Conclusion</p> <p>Our study provides the basis on which we can investigate the genetic programs controlling dendritic remodeling and programmed cell death of adult neurons, and the life-long maintenance of dendritic arbors.</p

Current classification and diversity of Fusarium species complex, the causal pathogen of Fusarium wilt disease of banana in Malaysia

The re-emergence of the Fusarium wilt caused by Fusarium odoratissimum (F. odoratissimum) causes global banana production loss. Thirty-eight isolates of Fusarium species (Fusarium spp.) were examined for morphological characteristics on different media, showing the typical Fusarium spp. The phylogenetic trees of Fusarium isolates were generated using the sequences of histone gene (H3) and translation elongation factor gene (TEF-1α). Specific primers were used to confirm the presence of F. odoratissimum. The phylogenetic trees showed the rich diversity of the genus Fusarium related to Fusarium wilt, which consists of F. odoratissimum, Fusarium grosmichelii, Fusarium sacchari, and an unknown species of the Fusarium oxysporum species complex. By using Foc-TR4 specific primers, 27 isolates were confirmed as F. odoratissimum. A pathogenicity test was conducted for 30 days on five different local cultivars including, Musa acuminata (AAA, AA) and Musa paradisiaca (AAB, ABB). Although foliar symptoms showed different severity of those disease progression, vascular symptoms of the inoculated plantlet showed that infection was uniformly severe. Therefore, it can be concluded that the Fusarium oxysporum species complex related to Fusarium wilt of banana in Malaysia is rich in diversity, and F. odoratissimum has pathogenicity to local banana cultivars in Malaysia regardless of the genotype of the banana plants

ショウジョウバエ感覚神経の樹状突起形態形成を制御するサブタイプ特異的な有糸分裂後転写プログラム

Yukako Hattori, Tadao Usui, Daisuke Satoh, Sanefumi Moriyama, Kohei Shimono, Takehiko Itoh, Katsuhiko Shirahige, Tadashi Uemura, Sensory-Neuron Subtype-Specific Transcriptional Programs Controlling Dendrite Morphogenesis: Genome-wide Analysis of Abrupt and Knot/Collier, Developmental Cell, Volume 27, Issue 5, 9 December 2013, Pages 530-544, ISSN 1534-5807京都大学0048新制・課程博士博士(生命科学)甲第18418号生博第298号新制||生||39(附属図書館)31276京都大学大学院生命科学研究科統合生命科学専攻(主査)教授 上村 匡, 教授 西田 栄介, 教授 荒木 崇学位規則第4条第1項該当Doctor of Philosophy in Life SciencesKyoto UniversityDFA

Interspecies Comparative Analyses Reveal Distinct Carbohydrate-Responsive Systems among Drosophila Species

栄養に柔軟に適応し成長するシステムの解明 --種間の適応能力の差を生む炭水化物応答機構--. 京都大学プレスリリース. 2019-09-04.Why fruit flies eat practically anything. 京都大学プレスリリース. 2019-09-05.During evolution, organisms have acquired variable feeding habits. Some species are nutritional generalists that adapt to various food resources, while others are specialists, feeding on specific resources. However, much remains to be discovered about how generalists adapt to diversified diets. We find that larvae of the generalists Drosophila melanogaster and D. simulans develop on three diets with different nutrient balances, whereas specialists D. sechellia and D. elegans cannot develop on carbohydrate-rich diets. The generalist D. melanogaster downregulates the expression of diverse metabolic genes systemically by transforming growth factor β (TGF-β)/Activin signaling, maintains metabolic homeostasis, and successfully adapts to the diets. In contrast, the specialist D. sechellia expresses those metabolic genes at higher levels and accumulates various metabolites on the carbohydrate-rich diet, culminating in reduced adaptation. Phenotypic similarities and differences strongly suggest that the robust carbohydrate-responsive regulatory systems are evolutionarily retained through genome-environment interactions in the generalists and contribute to their nutritional adaptabilities

Sensory-Neuron Subtype-Specific Transcriptional Programs Controlling Dendrite Morphogenesis: Genome-wide Analysis of Abrupt and Knot/Collier

神経細胞の個性を生み出すしくみの解明 －サブタイプ特異的な形づくりの遺伝子プログラム－. 京都大学プレスリリース. 2013-11-28.The transcription factors Abrupt (Ab) and Knot (Kn) act as selectors of distinct dendritic arbor morphologies in two classes of Drosophila sensory neurons, termed class I and class IV, respectively. We performed binding-site mapping and transcriptional profiling of isolated these neurons. Their profiles were similarly enriched in cell-type-specific enhancers of genes implicated in neural development. We identified a total of 429 target genes, of which 56 were common to Ab and Kn; these targets included genes necessary to shape dendritic arbors in either or both of the two sensory subtypes. Furthermore, a common target gene, encoding the cell adhesion molecule Ten-m, was expressed more strongly in class I than IV, and this differential was critical to the class-selective directional control of dendritic branch sprouting or extension. Our analyses illustrate how differentiating neurons employ distinct and shared repertoires of gene expression to produce class-selective morphological traits

Taxonomical studies on Botryosphaeriales in Japan

application/pdfFungi in the order Botryosphaeriales include pathogens that parasitize the leaves, fruits, and branches of plants and cause various diseases. These fungi are important plant pathogens globally, as they cause fruit rot, leaf blight, and branch blight in useful trees, such as fruit trees and trees that are used for urban greening and afforestation. In Japan, many tree diseases have been reported to be associated with Botryosphaeriales, but most of the Japanese species in this order have been described based solely on their morphological characteristics, with their molecular phylogenetic positions remaining unclear, highlighting the urgent need to review the Japanese Botryosphaeriales based on new criteria that reflect molecular phylogenetic relationships. Therefore, in this study, I conducted a taxonomic study of Japanese Botryosphaeriales fungi based on their morphological characteristics, culture characteristics, molecular phylogenetic relationships, and pathogenicities. The taxonomy of the species in the genus Phyllosticta, which are parasitic on conifer(Cupressaceae) trees in Japan, was conducted based on current criteria, including morphological characteristics, culture characteristics, phylogenetic relationships, and pathogenicities. Phylogenetic analyses revealed that this genus included several clades comprising plant pathogens that were isolated from a specific host as well as clades comprising endophytic species isolated from various conifer species. Each clade was recognized as a species based on the morphological characteristics and other features. Five species of Phyllosticta sensu stricto were recognized, two of which were newly recorded in the Japanese mycoflora. Furthermore, a new combination of P. pilospora and its epitype and an epitype and ex-type strain for P. cryptomeriae were proposed. To clarify the species diversity of Lasiodiplodia in Japan, I examined 30 Japanese isolates based on their morphological characteristics, culture characteristics, and phylogenetic relationships. Phylogenetic analyses using a matrix composed of ITS, tef1-α, tub2, and rpb2 sequences revealed that these isolates were divided into 11 clades that corresponded to L. theobromae, L. brasiliensis, L. swieteniae, L. pseudotheobromae, andLasiodiplodia spp. These species were also identified based on their morphological characteristics and the optimum growth temperature of each isolate, two of which were new additions to the Japanese mycoflora. In addition, four other species (L. latispora, L.parvispora, L. ryukyuensis, and L. yaguchii) were proposed. Reexamination of Japanese species in the genus Botryosphaeria isolated from 12 plant species belonging to ten families was carried out based on their morphological characteristics and molecular and phylogenetic analyses using the tef1-α, tub2, and rpb2 protein-coding regions and the ITS region of rDNA. These Japanese isolates were divided into five clades that were identified as B. dothidea, B. qingyuanensis, B. sinensis, andBotryosphaeria sp. Among these, B. qingyuanensis and B. sinensis have recently beenadded to the Japanese mycoflora and are not host-specific. In addition, B. tenuispora isolated from Leucothoe fontanesiana and insect galls on the leaves of Aucuba japonica was proposed as a new species. Reexamination of Japanese species in the genus Neofusicoccum was carried out based on their morphological characteristics and molecular phylogenetic relationships using the ITS, rpb2, tef1-α, and tub2 regions. These Japanese isolates were divided into five clades, which were recognized as the species N. parvum, other Neofusicoccum spp., and three new species proposed in this study (N. hyperici, N. miyakoense, and N.okinawaense). In addition, Physalospora laricina, which causes shoot blight in larch, was transferred to the genus Neofusicoccum and its epitype and ex-epitype isolates were proposed. their roles as plant pathogens, endophytes, and saprophytes in ecosystems.本文/Graduate school of Bioresources Mie University167

Taxonomical studies on Botryosphaeriales in Japan

application/pdf内容の要旨・審査結果の要旨/資源循環学専

Inter-organ Wingless/Ror/Akt signaling regulates nutrient-dependent hyperarborization of somatosensory neurons

Nutrition in early life has profound effects on an organism, altering processes such as organogenesis. However, little is known about how specific nutrients affect neuronal development. Dendrites of class IV dendritic arborization neurons in Drosophila larvae become more complex when the larvae are reared on a low-yeast diet compared to a high-yeast diet. Our systematic search for key nutrients revealed that the neurons increase their dendritic terminal densities in response to a combined deficiency in vitamins, metal ions, and cholesterol. The deficiency of these nutrients upregulates Wingless in a closely located tissue, body wall muscle. Muscle-derived Wingless activates Akt in the neurons through the receptor tyrosine kinase Ror, which promotes the dendrite branching. In larval muscles, the expression of wingless is regulated not only in this key nutrient-dependent manner, but also by the JAK/STAT signaling pathway. Additionally, the low-yeast diet blunts neuronal light responsiveness and light avoidance behavior, which may help larvae optimize their survival strategies under low-nutritional conditions. Together, our studies illustrate how the availability of specific nutrients affects neuronal development through inter-organ signaling

Cyclophilin B control of lysine post-translational modifications of skin type I collagen.

Covalent intermolecular cross-linking of collagen is essential for tissue stability. Recent studies have demonstrated that cyclophilin B (CypB), an endoplasmic reticulum (ER)-resident peptidyl-prolyl cis-trans isomerase, modulates lysine (Lys) hydroxylation of type I collagen impacting cross-linking chemistry. However, the extent of modulation, the molecular mechanism and the functional outcome in tissues are not well understood. Here, we report that, in CypB null (KO) mouse skin, two unusual collagen cross-links lacking Lys hydroxylation are formed while neither was detected in wild type (WT) or heterozygous (Het) mice. Mass spectrometric analysis of type I collagen showed that none of the telopeptidyl Lys was hydroxylated in KO or WT/Het mice. Hydroxylation of the helical cross-linking Lys residues was almost complete in WT/Het but was markedly diminished in KO. Lys hydroxylation at other sites was also lower in KO but to a lesser extent. A key glycosylation site, α1(I) Lys-87, was underglycosylated while other sites were mostly overglycosylated in KO. Despite these findings, lysyl hydroxylases and glycosyltransferase 25 domain 1 levels were significantly higher in KO than WT/Het. However, the components of ER chaperone complex that positively or negatively regulates lysyl hydroxylase activities were severely reduced or slightly increased, respectively, in KO. The atomic force microscopy-based nanoindentation modulus were significantly lower in KO skin than WT. These data demonstrate that CypB deficiency profoundly affects Lys post-translational modifications of collagen likely by modulating LH chaperone complexes. Together, our study underscores the critical role of CypB in Lys modifications of collagen, cross-linking and mechanical properties of skin