Chromosome structure and behaviour in Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae) germ cells and early embryo

Chromosome structure and behaviour in both meiosis of the germ cells and mitosis of the embryo from fertilisation to the two-cell stage in Bursaphelenchus xylophilus were examined by DAPI staining and three-dimensional reconstruction of serial-section images from confocal laser-scanning microscopy. By this method, each chromosome’s shape and behaviour were clearly visible in early embryogenesis from fertilisation through the formation and fusion of the male and female pronuclei to the first mitotic division. The male pronucleus was bigger than that of the female, although the oocyte is larger and richer in nutrients than the sperm. From the shape of the separating chromosomes at anaphase, the mitotic chromosomes appeared to be polycentric or holocentric rather than monocentric. Each chromosome was clearly distinguishable in the male and female germ cells, pronuclei of the one-cell stage embryo, and the early embryonic nuclei. The haploid number of chromosomes (N) was six (2n = 12), and all chromosomes appeared similar. The chromosome pair containing the ribosomal RNA-coding site was visualised by fluorescence in situ hybridisation. Unlike the sex determination system in Caenorhabditis elegans (XX in hermaphrodite and XO in male), the system for B. xylophilus may consist of an XX female and an XY male

Pine Wilt Disease: insights into the Biology of Bursaphelenchus xylophilus-associated bacteria.

Pine wilt disease (PWD) is caused by the parasitic nematode Bursaphelenchus xylophilus (pinewood nematode; PWN), which infects mainly Pinus spe- cies with the aid of an insect-vector, Monochamus sp.. Bacteria isolated from B. xylophilus are being con- sidered as a fourth element in this disease complex. Their precise roles of these organisms in this interac- tion are unclear, as both beneficial and pathogenic bacteria have been found associated with PWD. Previously, we have shown the high oxidative stress tolerance of the PWN-associated bacteria Serratia sp. LCN16 and Serratia marcescens PWN146, and their beneficial effects towards the nematode under harsh oxidative stress conditions. Here, we present a de- tailed analysis of the genome sequences of these two PWN-associated bacteria and provide new insights into their biology and contributions to PWD and the PWN. Serratia sp. LCN16 is phylogenetically most closely related to the phytosphere group of Serratia, and shares many features with endophytes (plant- associated bacteria). These include genes coding for plant polymer degrading enzymes, iron uptake/ transport, siderophore and phytohormone synthesis, aromatic compound degradation and detoxification enzymes. Serratia marcescens PWN146 can also with- stand and colonize the plant environment, without having any deleterious effects towards B. xylophilus nor to the nematode model C. elegans. PWN146 has the potential to interfere with plant metabolism via hormonal pathways or nutritional acquisition (i.e. iron), and to be competitive against other bacteria and fungi, through resource acquisition or produc- tion of antimicrobial compounds

Endometriosis of the Appendix Resulting in Perforated Appendicitis

Endometriosis is a relatively common disease among women of reproductive age. However, gastrointestinal endometriosis is rare and endometriosis of the appendix resulting in perforated appendicitis is even rarer. We experienced a case of endometriosis of the appendix manifesting as panperitonitis caused by perforation of the appendix. The patient was a 35-year-old woman who was hospitalized with an acute abdomen. She was diagnosed with panperitonitis and underwent urgent laparotomy. When perforation of the appendix was detected, appendectomy and intraperitoneal drainage were performed. Pathological examination revealed endometriosis extending from the muscularis propria to the subserosa, and a diagnosis of endometriosis of the appendix was made. We consider the relevant literature describing the mechanism by which endometriosis of the appendix occurs, and the association between endometriosis of the appendix and acute appendicitis

Composition of the Cockroach Gut Microbiome in the Presence of Parasitic Nematodes

Cockroaches are parasitized by thelastomatid nematodes, which live in an obligate manner in their hindgut and interact with the resident microbial community. In the present study, a composition analysis was performed on the gut microbiome of Periplaneta fuliginosa and P. americana to investigate natural and artificial infection by thelastomatid nematodes. Nine librar- ies of the 16S rRNA gene V3–V4 region were prepared for pyrosequencing. We examined the complete gut microbiome (fore-, mid-, and hindgut) of lab-reared P. fuliginosa naturally infected with the parasitic nematode Leidynema appendiculatum and those that were nematode-free, and complemented our study by characterizing the hindgut microbial communities of lab-reared P. americana naturally infected with Hammerschmidtiella diesingi and Thelastoma bulhoesi, artificially infected with L. appendiculatum, and those that were nematode-free. Our results revealed that the fore- and midgut of naturally infected and nematode-free P. fuliginosa have close microbial communities, which is in contrast with hindgut communities; the hindgut communities of both cockroaches exhibit higher microbial diversities in the presence of their natural parasites and marked differences were observed in the abundance of the most representative taxa, namely Firmicutes, Proteobacteria, and Bacteroidetes. Our results have provided basic information and encourage further studies on multitrophic interactions in the cockroach gut as well as the thelastomatid nematodes that play a role in this environment

The composition of hindgut microbiota of Periplaneta japonica in the presence of thelastomatid parasitic nematodes

Thelastomatid nematodes (Nematoda: Oxyurida: Thelastomatoidea) are obligatory parasites that occur naturally in the hindgut of arthropods. Their origin and impact in the host is still unknown. Previous studies showed that the presence of thelastomatid nematodes in the gut of cockroaches (Periplaneta fuliginosa and P. americana) could influence the composition of their hindgut microflora. Through a metagenomic approach (16S rRNA V3-V4 sequencing), we have characterized the hindgut microbiome of P. japonica in the presence of thelastomatid nematodes (L1986, natural parasitic nematode Protrellus sp. present as a natural infection condition; and L1987, non-native parasitic nematode Leidynema appendiculatum present as an artificial infection condition). The hindgut microbiome of P. japonica in both conditions were mainly composed of Bacteroidetes, Firmicutes and Proteobacteria. Moreover, the natural and artificial infection by thelastomatid nematodes lead to shifts in the relative abundance of these main resident flora as seen in P. americana. The OTUs percentage of Bacteroidetes and Proteobacteria were higher in P. japonica infected with Protrellus sp. (L1986) than in P. japonica infected by L. appendiculatum (L1987), while OTUs from Firmicutes phylum was higher in L1987 than in L1986. This study fosters a detailed investigation in the role played by these animal parasites in their host insect

咬合接触に関与しない口蓋床の口蓋部形態が睡眠中の咬筋筋活動に与える影響

This study aimed to reveal whether masseter muscle activity during sleep is affected by the difference in design of non-occlusal intraoral appliances on hard palate. Eight healthy Japanese participants were selected and wore each of the four types of appliances (horse shoe, thin, thick and medium thick) during sleep for one week with a one week interval without appliance during sleep. A masseter muscle electromyograph (EMG) was recorded during sleep. The EMG activities were analyzed by calculating the number of bursts per hour, episodes per hour, and bursts per episode. The EMG parameters with the thick type appliance were significantly lower than the baseline condition without appliance. In this study, it is suggested that a thick type appliance has an active effect on suppression of masseter muscle activity

Pinewood nematode-associated bacteria contribute to oxidative stress resistance of Bursaphelenchus xylophilus

Background: Pine wilt disease (PWD) caused by the pinewood nematode Bursaphelenchus xylophilus is one of the most serious forest diseases in the world. The role of B. xylophilus-associated bacteria in PWD and their interaction with the nematode, have recently been under substantial investigation. Several studies report a potential contribution of the bacteria for the PWD development, either as a helper to enhance the pathogenicity of the nematode or as a pathogenic agent expressing interesting traits related to lifestyle host-adaptation. Results: We investigated the nematode-bacteria interaction under a severe oxidative stress (OS) condition using a pro-oxidant hydrogen peroxide and explored the adhesion ability of these bacteria to the cuticle surface of the nematodes. Our results clearly demonstrated a beneficial effect of the Serratia spp. (isolates LCN-4, LCN-16 and PWN-146) to B. xylophilus under the OS condition. Serratia spp. was found to be extremely OS-resistant, and promote survival of B. xylophilus and down-regulate two B. xylophilus catalase genes (Bxy-ctl-1 and Bxy-ctl-2). In addition, we show that the virulent isolate (Ka4) of B. xylophilus survives better than the avirulent (C14-5) isolate under the OS condition. The bacterial effect was transverse for both B. xylophilus isolates. We could not observe a strong and specific adhesion of these bacteria on the B. xylophilus cuticle surface. Conclusions: We report, for the first time, that B. xylophilus associated bacteria may assist the nematode opportunistically in the disease, and that a virulent B. xylophilus isolate displayed a higher tolerance towards the OS conditions than an avirulent isolate

A Framework For Refining Text Classification and Object Recognition from Academic Articles

With the widespread use of the internet, it has become increasingly crucial to extract specific information from vast amounts of academic articles efficiently. Data mining techniques are generally employed to solve this issue. However, data mining for academic articles is challenging since it requires automatically extracting specific patterns in complex and unstructured layout documents. Current data mining methods for academic articles employ rule-based(RB) or machine learning(ML) approaches. However, using rule-based methods incurs a high coding cost for complex typesetting articles. On the other hand, simply using machine learning methods requires annotation work for complex content types within the paper, which can be costly. Furthermore, only using machine learning can lead to cases where patterns easily recognized by rule-based methods are mistakenly extracted. To overcome these issues, from the perspective of analyzing the standard layout and typesetting used in the specified publication, we emphasize implementing specific methods for specific characteristics in academic articles. We have developed a novel Text Block Refinement Framework (TBRF), a machine learning and rule-based scheme hybrid. We used the well-known ACL proceeding articles as experimental data for the validation experiment. The experiment shows that our approach achieved over 95% classification accuracy and 90% detection accuracy for tables and figures.Comment: This paper has been accepted at 'The International Symposium on Innovations in Intelligent Systems and Applications 2023 (INISTA 2023)