Direction-dependent differences in the quality and quantity of horizontal reaching in people after stroke.

Arm reaching is often impaired in individuals with stroke. Nonetheless, how aiming directions influence reaching performance and how such differences change with motor recovery over time remain unclear. Here, we elucidated kinematic parameters of reaching toward various directions in people with poststroke hemiparesis in the subacute phase. A total of 13 and 15 participants with mild and moderate-to-severe hemiparesis, respectively, performed horizontal reaching in eight directions with their more-affected and less-affected sides using an exoskeleton robotic device at the time of admission to and discharge from the rehabilitation ward of the hospital. The movement time, path length, and number of velocity peaks were computed for the mild group (participants able to reach toward all eight directions). In addition, the total amount of displacement (i.e., movement quantity) toward two simplified directions (mediolateral or anteroposterior) was evaluated for the moderate-to-severe group (participants who showed difficulty in completing the reaching task). Motor recovery was evaluated using the Fugl-Meyer assessment. The mild group showed worse values of movement parameters during reaching in the anteroposterior direction, irrespective of the side of the arm or motor recovery achieved. The moderate-to-severe group exhibited less movement toward the anteroposterior direction than toward the mediolateral direction at admission; however, this direction-dependent bias in movement quantity decreased, with the movement expanding toward the anteroposterior direction with motor recovery at discharge. These results suggest that direction-dependent differences in the quality and quantity of reaching performance exist in people after stroke, regardless of the presence or severity of hemiparesis. This highlights the need to consider the task work area when designing rehabilitative training.NEW & NOTEWORTHY Arm reaching, a fundamental function required for the upper extremities, is often impaired after stroke due to muscle weakness and abnormal synergies. Nonetheless, how aiming directions influence performance remains unclear. Here, we report that direction-dependent differences in the quality and quantity of reaching performance exist, surprisingly regardless of the presence or severity of hemiparesis. This result highlights the need to consider the task work area when designing rehabilitative training.

Characteristics of people seeking consultation after progressing to severe dementia: A mixed-method analysis.

OBJECTIVES: This explores the characteristics of patients with worsening dementia who did not receive a specialized medical examination or care. METHODS: This study utilized a mixed methods analysis. Of the 2712 people who received the Mini Mental State of Examination (MMSE) at the Community Consultation Center for Citizens with MCI and Dementia between December 2007 and December 2019, 1413 people who scored 23 points or less were included. Participants were categorized into mild, moderate, and severe groups, based on their MMSE scores. Participants' characteristics-gender, age, presence or absence of an escort, demographics, family type, and presence or absence of a family doctor-were compared between the groups. To further understand the severe group's characteristics, clinical psychologists recorded consultation forms were categorized. RESULTS: More than 80% of the patients in each group had a family doctor. Moreover, all the severe groups had escorts, and the role of family members and supporters was important for the consultation. In the severe group, 29 patients had never received specialized medical care. Their characteristics were coded "non-existence" (fewer people or opportunities to notice their needs), "connection failure" (a lack of access or connections to consultations), and "evaluation failure" (not recognized as a problem requiring consultation). CONCLUSIONS: It is necessary to improve primary physician education, disseminate knowledge, and raise awareness about dementia, besides building and strengthening networks to alleviate the isolation of dementia patients and their families. The psychological aspects of family members' denial regarding their family members with dementia must be addressed through intervention.

Metagenomic profile of caudal fin morphology of farmed red sea bream Pagrus major.

The morphology of farm-reared fish often differs from that of their wild counterparts, impacting their market value. Two caudal fin tip shapes, acutely angled and blunted, are recognized in farmed populations of red sea bream Pagrus major. The angled form is preferred by consumers over the blunt since it resembles that of wild fish. Discovering the cause of the blunted tip is crucial to maximizing the commercial value of farmed red sea bream. We hypothesized that the blunt fin tip is the result of opportunistic bacteria and conducted partial 16S rRNA metagenomic barcoding and generated a clone library of the 16S rRNA gene to compare bacterial communities of the 2 fin forms. Metagenomic barcoding revealed an abundance of 5 bacterial genera, Sulfitobacter, Vibrio, Tenacibaculum, Psychrobacter, and an unknown genus of Rhodobacteraceae, on the caudal fin surface. Sulfitobacter was significantly more common on the angled caudal fin than the blunted. Vibrio is the dominant genus on the blunted caudal fin. The clone library identified these genera to species level, and Sulfitobacter sp., Vibrio harveyi, Tenacibaculum maritimum, and Psychrobacter marincola were frequently observed in blunt caudal fins. Our results suggest that opportunistic pathogenic bacteria such as V. harveyi and T. maritimum are not the primary cause of caudal fin malformation, and multiple factors such as combinations of injury, stress, and pathogenic infection may be involved. The reason for the significantly greater occurrence of Sulfitobacter sp. in the angled caudal fin is unknown, and further investigation is needed.

Differences in the difficulty of subtasks comprising the toileting task among patients with subacute stroke: A cohort study.

INTRODUCTION: Toileting comprises multiple subtasks, and the difficulty of each is critical to determining the target and priority of intervention. The study aimed to examine the difficulty of subtasks that comprise toileting upon admission and the reacquisition of skills of subtasks during hospitalization. MATERIALS AND METHODS: This was a single-center prospective cohort study. We enrolled 101 consecutive stroke patients (mean age: 69.3 years) admitted to subacute rehabilitation wards. The independence in each of the 24 toileting subtasks was assessed using the Toileting Tasks Assessment Form (TTAF) every two or four weeks. The number of patients who were independent upon admission, as well as those who were not independent upon admission but became independent during hospitalization, was examined in each subtask. RESULTS: The most difficult subtask upon admission was "Lock the wheelchair brakes" (16.8% of patients were independent), followed by "Turn while standing (before urination/defecation)" (17.8%), "Pull the lower garments down" (18.0%), "Turn while standing (after urination/defecation)" (18.8%), "Pull the lower garments up and adjust them" (18.8%), and "Maintain a standing position (before urination/defecation)" (18.8%). The most difficult subtask for those who were not independent but became independent was "Dispose of incontinence pad/sanitary items" (19.3%), followed by "Press the nurse call button (after urination/defecation)" (28.3%), "Take the foot off the footrest and place it on the ground" (28.6%), and "Clean up after urination/defecation" (29.0%). CONCLUSIONS: The difficult subtasks upon admission and those for reacquired skills were different. The most difficult subtasks upon admission were main tasks, and the difficult subtasks in reacquiring skills were preparatory tasks.

Heavy oil exposure suppresses antiviral activities in Japanese flounder Paralichthys olivaceus infected with viral hemorrhagic septicemia virus (VHSV).

A combined treatment of heavy oil (HO) exposure and virus infection induces increased mortality in Japanese flounder (Paralichthys olivaceus). In this study, we addressed how HO exposure affects the immune system, especially antiviral activities, in Japanese flounder. The fish were infected with viral hemorrhagic septicemia virus (VHSV), followed by exposure to HO. We analyzed virus titers in the heart and mRNA expression in the kidney of surviving fish. The virus titers in fish exposed to heavy oil were higher than the threshold for onset. The results suggest that HO exposure may allow the replication of VHSV, leading to higher mortality in the co-treated group. Gene-expression profiling demonstrated that the expression of antiviral-activity-related genes, such as those for interferon and apoptosis induction, were lower in the co-treated group than in the group with VHSV infection only. These results helped explain the high virus titers in fish treated with both stressors. Thus, interferon production in the virus-infected cells and apoptosis induction by natural killer cells worked normally in the VHSV-infected fish without HO exposure, but these antiviral activities were slightly suppressed by HO exposure, possibly leading to extensive viral replication in the host cells and the occurrence of VHS.

Innate immunity in the edible ascidian Halocynthia roretzi developing soft tunic syndrome: Hemolymph can eliminate the causative flagellates and discriminate allogeneic hemocytes.

The infection of the kinetoplastid flagellate Azumiobodo hoyamushi causes soft tunic syndrome that often results in mass mortality in the aquaculture of the edible ascidian Halocynthia roretzi. In the diseased ascidian individuals, the flagellates are exclusively found in the tunic matrix that entirely cover the epidermis, and never invade into internal tissues, such as a mantle. The present study for the first time demonstrated that the ascidian blood plasma and hemolymph have an activity to agglutinate and disintegrate the flagellates, suggesting the innate immunity protects the internal tissue from the invasion of A. hoyamushi. This activity is indifferent between the healthy and the diseased individuals. Allo-specific recognition and cytotoxic reaction among ascidian hemocytes, so-called contact reaction, occur among the individuals of healthy-healthy, healthy-diseased, and diseased-diseased combination, and therefore, the hemocytes from diseased individuals still retain the allo-reactivity. Moreover, the allo-reactive combinations are not changed under the presence of the flagellates, indicating the flagellates neither suppress nor induce the effector system of the contact reaction. These results suggest that the infection of A. hoyamushi does not impair the innate immunity in the ascidian hemolymph.

Shock-absorbing effect of flooring-adopted mechanical metamaterial technology and its influence on the gait and balance of older adults.

OBJECTIVE: To elucidate the performance of a shock-absorbing floor material with a mechanical metamaterial (MM-flooring) structure and its effect on the gait and balance of older adults. METHODS: The drop-weight impact was applied to evaluate the shock-absorbing performance. The falling weight was adjusted equivalent to the energy exerted on the femur of an older woman when she falls, which was evaluated on the MM-flooring and six other flooring materials.Nineteen healthy people over the age of 65 years participated in the gait and balance evaluations. The timed up and go and two-step tests were adopted as gait performance tests, and the sway-during-quiet-balance test with force plates and the functional reach test (FRT) were adopted as balance tests. All the participants underwent these tests on the MM-flooring, shock-absorbing mat and rigid flooring. RESULTS: The shock-absorbing performance test revealed that MM-flooring has sufficient shock-absorbing performance, and suggesting that it may reduce the probability of fractures in the older people when they fall. The results of the gait performance test showed that the participants demonstrated the same gait performance on the MM-flooring and the rigid floor. In the quiet standing test, MM-flooring did not affect the balance function of the participants to the same extent as the rigid floor, compared with the shock-absorbing mat. In the FRT, no significant differences were found for any of the flooring conditions. CONCLUSIONS: MM-flooring has the potential to prevent fractures attributed to falls and does not affect the gait or balance of older adults.

Difficulty of the subtasks comprising bed-wheelchair transfer in patients with subacute strokes: A cohort study.

OBJECTIVE: Bed-wheelchair transfer comprises multiple subtasks; hence, it is important to know the difficulty of each subtask to identify and prioritize subtasks that must be practiced. This study aimed to investigate the difficulty of the subtasks that comprise bed-wheelchair transfer upon admission and reacquiring subtask skills during hospitalization. MATERIALS AND METHODS: This was a single-center prospective cohort study. We enrolled 137 consecutive stroke patients (mean age: 69.8 years) admitted to subacute rehabilitation wards who used wheelchairs upon admission. The degree of independence in each of the 25 subtasks that comprised transferring was assessed using the Bed-wheelchair transfer Tasks Assessment Form every 2 weeks. The number of patients who were independent in the subtasks upon admission and those who were not but became independent during hospitalization were examined. RESULTS: The most difficult subtask for independent patients upon admission was "Manipulate the handrail for the bed" (18.3%), followed by "Ready the wheelchair for transfer" (19.3%), "Maneuver the wheelchair toward the appropriate place for transfer to the bed" (20.6%), "Wear shoes/brace" (24.8%), and "Turn while standing" (25.5%). The most difficult subtask for those who were not independent but became independent was "Ready the wheelchair for transfer" (32.1%), followed by "Manipulate the handrail for the bed" (32.9%), "Press the nurse call button" (36.4%), "Press the nurse call button (wheelchair-to-bed)" (36.7%), and "Lock the wheelchair brakes" (37.3%). CONCLUSIONS: Subtasks related to preparation for transfer were difficult upon admission, and this tendency became more pronounced during the skill acquisition process.

Stroke Patients with Nearly Independent Transfer Ability are at High Risk of Falling.

OBJECTIVES: To examine the relationship between patients' transfer ability and fall risk in stroke patients during hospitalization. MATERIALS AND METHODS: We retrospectively enrolled 237 stroke patients who were transferred to a convalescent rehabilitation ward from acute wards in the same hospital. Using incident reports, we investigated their fall rates and activity status at the falls according to their transfer abilities, which were assessed with Functional Independence Measure (FIM) transfer scores. The bi-weekly time trend of fall rates in all patients and in three subgroups based on FIM transfer scores of 1-3, 4-5, and 6-7, and activity status at the falls, were investigated. In addition, changes of patients' transfer ability on admission, at the first fall, and at discharge were investigated among falling patients. RESULTS: The fall rate was the greatest in patients with a FIM transfer score of 4 (14.3 times/1000 person-days). The majority of falls for patients with a FIM transfer score of 1 occurred at the activity status of "on the bed" and "sitting", while three quarters of patients with a FIM score of 7 had falls during "standing" and "walking". No longitudinal trend in fall rates was found overall; however, the fall rate trends differed depending on the FIM transfer score. The majority of the patients who fell required full assistance for transfers upon admission but required no assistance at discharge. CONCLUSIONS: Fall risk differed among patients with various transfer abilities; the greatest risk was in those who needed minimal assistance for transfers.

Patients' thoughts on their falls in a rehabilitation hospital: a qualitative study of patients with stroke.

BACKGROUND: Patients with stroke in rehabilitation wards are at an increased risk of falling. Although patients' participation in establishing medical safety is considered crucial, there is limited evidence on their perspectives of falls. This study aims to comprehensively elucidate the subjective falling experience of patients with stroke who have been admitted to rehabilitation wards. METHODS: Twenty-three consecutive patients with stroke (44 to 90 years) who experienced a fall during hospitalisation were interviewed within 1 week after the fall, and thematic analysis was used to analyse the data. RESULTS: Five themes surrounding fall events were extracted from the narratives: 'Psychological background before the action', 'Support for the action', 'Direct causes of the fall', 'Patients' awareness after the fall', and 'Changes in attitudes and behaviours after the fall'. 'Psychological background before the action' comprised hastiness or hesitation to call for help. Participants often took an action based on 'Support for the action' derived from their past experiences of moving safely, their confidence, and/or motivation to challenge themselves to move. 'Direct causes of the fall' consisted of unfamiliar actions, training fatigue, the surrounding environment, reduced physical function due to paralysis, lack of attention, overconfidence in their ability, and insufficient prediction of falls. 'Patients' awareness after the fall' consisted of re-affirming difficult movements, the need for rehabilitation, a reduced ability to move, an increased risk of falling, the need for attention while moving, a fear of falling, and a lack of lessons learned from falling. Finally, patients demonstrated 'Changes in attitudes and behaviours after the fall' such as embodying a positive attitude to cope with the risk of falling or behavioural changes to reduce the risk of falling. CONCLUSIONS: Comprehensive information on patients' perspectives before and after the fall was elucidated, uncovering many aspects including the psychological background for why patients engaged in risky behaviours resulting in falls, presence of positive thinking, and behaviour after the fall. By incorporating the patients' views on fall incidences and their assessment, we can develop appropriate prevention strategies against falls.

Aryl Hydrocarbon Receptor Signaling Is Functional in Immune Cells of Rainbow Trout (Oncorhynchus mykiss).

The arylhydrocarbon receptor (AhR) is an important signaling pathway in the immune system of mammals. In addition to its physiological functions, the receptor mediates the immunotoxic actions of a diverse range of environmental contaminants that bind to and activate the AhR, including planar halogenated aromatic hydrocarbons (PHAHs or dioxin-like compounds) and polynuclear aromatic hydrocarbons (PAHs). AhR-binding xenobiotics are immunotoxic not only to mammals but to teleost fish as well. To date, however, it is unknown if the AhR pathway is active in the immune system of fish and thus may act as molecular initiating event in the immunotoxicity of AhR-binding xenobiotics to fish. The present study aims to examine the presence of functional AhR signaling in immune cells of rainbow trout (Oncorhynchus mykiss). Focus is given to the toxicologically relevant AhR2 clade. By means of RT-qPCR and in situ hybdridization, we show that immune cells of rainbow trout express ahr 2α and ahr 2ß mRNA; this applies for immune cells isolated from the head kidney and from the peripheral blood. Furthermore, we show that in vivo as well as in vitro exposure to the AhR ligand, benzo(a)pyrene (BaP), causes upregulation of the AhR-regulated gene, cytochrome p4501a, in rainbow trout immune cells, and that this induction is inhibited by co-treatment with an AhR antagonist. Taken together, these findings provide evidence that functional AhR signaling exists in the immune cells of the teleost species, rainbow trout.

Molecular cloning, characterization and expression analysis of complement components in red sea bream (Pagrus major) after Edwardsiella tarda and red sea bream Iridovirus (RSIV) challenge.

The complement system plays an important role in immune regulation and acts as the first line of defense against any pathogenic attack. To comprehend the red sea bream (Pagrus major) immune response, three complement genes, namely, pmC1r, pmMASP and pmC3, belonging to the classical, lectin and alternative complement cascade, respectively, were identified and characterized. pmC1r, pmMASP, and pmC3 were comprised of 2535, 3352, and 5735 base mRNA which encodes 732, 1029 and 1677 aa putative proteins, respectively. Phylogenetically, all the three studied genes clustered with their corresponding homologous clade. Tissue distribution and cellular localization data demonstrated a very high prevalence of all the three genes in the liver. Both bacterial and viral infection resulted in significant transcriptional alterations in all three genes in the liver with respect to their vehicle control counterparts. Specifically, bacterial challenge affected the pmMASP and pmC3 expression, while the viral infection resulted in pmC1r and pmC3 mRNA activation. Altogether, our data demonstrate the ability of pmC1r, pmMASP and pmC3 in bringing about an immune response against any pathogenic encroachment, and thus activating, not only one, but all the three complement pathways, in red sea bream.

Measurement of Tunic Hardness in an Edible Ascidian, Halocynthia roretzi, with Remarks on Soft Tunic Syndrome.

The infection caused by a kinetoplastid flagellate, Azumiobodo hoyamushi, in an ascidian, Halocynthia roretzi, results in softening of the tunic, and finally death. This disease is usually recognized using palpation of the softening tunic, and A. hoyamushi infection is detectable using microscopy or PCR amplification of specific gene fragments. The present study is the first quantitative evaluation of the symptoms of soft tunic syndrome by measuring the amount of bending (bending) and the peak force required to pierce the tunic (force). There was a strong correlation between bending and force. Correlation analyses among other parameters (ascidian total weight, tunic thickness, and tunic water content) indicated that larger ascidians had harder and thicker tunics with a higher water content. As compared to the tunic of healthy individuals, softened tunic was thinner and had lower water content. Infected tunics thus possibly lose water and become softer and thinner. Mechanisms for maintaining the appropriate water level content may be crucial for preventing tunic softening.

Tunic extract of the host ascidian attracts the causal agent of soft tunic syndrome, Azumiobodo hoyamushi (Kinetoplastea: Neobodonida).

Azumiobodo hoyamushi, a kinetoplastid flagellate, is the causative agent of soft tunic syndrome, an infectious disease of the edible ascidian Halocynthia roretzi. The flagellate is thought to invade the tunic matrix via a damaged area of the tunic on the siphon wall. We hypothesized that the flagellate locates the tunic entry site by a chemotactic response to soluble substances diffused from the host ascidians. To investigate this hypothesis, we examined whether the flagellate shows a chemotactic response to tissue extracts (tunic and other tissues) from the host ascidian H. roretzi. We tested extracts from 5 tissues as well as hemolymph. Only the tunic extract showed significant positive chemotactic activity, and the activity decreased with increasing dilution. Furthermore, autoclaved tunic extract, extracts from diseased individuals, and extract from the styelid ascidian Styela clava also had chemotactic activity, although the activities were lower than that of tunic extract from healthy H. roretzi. Ultrafiltration of the tunic extract through a 3 kDa cutoff membrane completely abrogated the activity; the ultrafiltration retentate still showed activity. Thus, the soluble factors that attract the flagellate are present exclusively in the tunic extract, and the chemotactic factors are larger than 3 kDa. Our experiments also suggested that the tunic extract contains both heat-stable and heat-labile factors. We conclude that the flagellate locates the tunic entry site by chemotaxis toward soluble factors that diffuse from a damaged area of the tunic on the siphon wall.

Feasibility of applying the psychosocial intervention STrAtegies for RelaTives to family caregivers of patients with dementia: a case report.

As the number of people with dementia in Japan continues to rise, family caregivers are experiencing an increasing care burden. Previous research has shown that this care burden can affect family caregivers' physical and mental health. Therefore, providing support for caregivers of family members with dementia has become an urgent issue in the country. The purpose of this study was to investigate the feasibility of applying STrAtegies for RelaTives (START), a psychosocial intervention programme developed in the UK to improve caregivers' moods and quality of life, to Japanese family caregivers. Specifically, in this paper, we provide a detailed description of the application of the Japanese version of START to a female caregiver. Our investigation found that the Japanese version of START is a feasible option for alleviating the mental and physical burden on family caregivers of patients with dementia. This result provides preliminary support for the wider application of START in Japan, as it can decrease care burden and improve the daily lives of caregivers of people with dementia. It also supports the development and implementation of other systems that can provide similar services for other caregivers.

Adenosine A1 receptors measured with 11 C-MPDX PET in early Parkinson's disease.

Adenosine A1 receptors (A1 Rs) interact negatively with dopamine D1 receptors (D1 Rs) in neurons of the basal ganglia's direct pathway, while adenosine A2A receptors (A2A Rs) negatively interact with dopamine D2 receptors (D2 Rs) in indirect-pathway neurons. The aim of this study was to investigate the cerebral density of A1 Rs in Parkinson's disease (PD) in its early stages, using PET scans with the radioligand 8-dicyclopropylmethyl-1-11 C-methyl-3-propylxanthine (11 C-MPDX). We studied 10 drug-naïve patients with early PD. Each patient was also examined for dopamine transporters (DATs) and D2 Rs by PET using 11 C-2-ß-carbomethoxy-3-ß-(4-fluorophenyl)-tropane (11 C-CFT) and 11 C-raclopride (11 C-RAC), respectively. Ten elderly, healthy volunteers were recruited as controls for 11 C-MPDX PET scanning and eight elderly volunteers were recruited as controls for 11 C-CFT and 11 C-RAC PET scanning. The PET scans revealed a decrease in the uptake ratio index (URI) of 11 C-CFT and an increase in the URI of 11 C-RAC in patients. In the temporal lobe, the binding potential for 11 C-MPDX was higher in the patient group than in healthy subjects, but not in the other regions examined, including the striatum. In patients, we observed motor-symptom asymmetry and a relationship between parkinsonism and the striatal density of DATs, but not A1 R density. In the putamen of early PD, asymmetrical down-regulation of A2A Rs is likely a compensatory mechanism in response to a decrease in dopamine. However, our study suggests that A1 Rs are unaltered in the putamen of early PD.

Encystment and excystment of kinetoplastid Azumiobodo hoyamushi, causal agent of soft tunic syndrome in ascidian aquaculture.

Soft tunic syndrome in the edible ascidian Halocynthia roretzi is caused by the kinetoplastid flagellate Azumiobodo hoyamushi, which was found to assume a fusiform cell form with 2 flagella in axenic, pure culture. When the flagellate form was incubated in sterilized artificial seawater (pH 8.4), some of the cells became cyst-like and adhered to the bottom of the culture plate. The cyst-like forms were spherical or cuboidal, and each had 2 flagella encapsulated in its cytoplasm. Encystment was also induced in culture medium alkalified to the pH of seawater (8.4) but not in unmodified (pH 7.2) or acidified media (pH 6.4). More than 95% of the cyst-like cells converted to the flagellate form within 1 d following transfer to seawater containing ascidian tunic extracts from host ascidians. The cyst-like cells were able to survive in seawater with no added nutrients for up to 2 wk at 20°C and for a few months at 5 to 15°C. The survival period in seawater depended on temperature: some cyst-like cells survived 3 mo at 10°C, and ca. 95% of these converted to flagellate forms in seawater containing tunic extracts. Thus, A. hoyamushi is able to persist under adverse conditions in a cyst-like form able to adhere to organic and inorganic substrata for protracted periods of time.

Cellulose is not degraded in the tunic of the edible ascidian Halocynthia roretzi contracting soft tunic syndrome.

Soft tunic syndrome is a fatal disease in the edible ascidian Halocynthia roretzi, causing serious damage to ascidian aquaculture in Korea and Japan. In diseased individuals, the tunic, an integumentary extracellular matrix of ascidians, softens and eventually tears. This is an infectious disease caused by the kinetoplastid flagellate Azumiobodo hoyamushi. However, the mechanism of tunic softening remains unknown. Because cellulose fibrils are the main component of the tunic, we compared the contents and structures of cellulose in healthy and diseased tunics by means of biochemical quantification and X-ray diffractometry. Unexpectedly, the cellulose contents and structures of cellulose microfibrils were almost the same regardless of the presence or absence of the disease. Therefore, it is unlikely that thinning of the microfibrils occurred in the softened tunic, because digestion should have resulted in decreases in crystallinity index and crystallite size. Moreover, cellulase was not detected in pure cultures of A. hoyamushi in biochemical and expressed sequence tag analyses. These results indicate that cellulose degradation does not occur in the softened tunic.

Host responses of Japanese flounder Paralichthys olivaceus with lymphocystis cell formation.

Lymphocystis disease virus (LCDV) is the causative agent of lymphocystis disease (LCD). In this study, we investigated the mechanisms of lymphocystis cell (LCC) formation from the viewpoint of gene expression changes in the infected fish. LCC occurrence and virus titers in the experimentally infected Japanese flounder, Paralichthys olivaceus were monitored by visual confirmation and real-time PCR, respectively. The gene expression changes in the fish fin were investigated by microarray experiments. LCCs firstly appeared in the fish at 21 days post infection (dpi). LCD incidence increased with time and reached 92.9% at 62 dpi. LCDV genome was firstly detected from dorsal fins at 14 dpi, and the relative amount of the genome gradually-increased until 56 dpi. Since the occurrence of LCC was approximately synchronized with increasing of the virus genome, virus replication might play important roles for LCC formation. The microarray detected a few gene expression changes until 28 dpi. However, the number of expression changed genes dramatically increased between 28 and 42 dpi in which LCCs formation was active. From the microarray data analyses, apoptosis and cell division related genes were down-regulated, whereas cell fusion and collagen related genes were up-regulated at 42 dpi. Together with the observation of morphological changes of LCCs in previous reports, it is suggested that the following steps are involved in LCC formation: the virus infected cells were (1) inhibited apoptotic death and (2) cell division before enlargement, (3) hypertrophied by cell fusion, and (4) surrounded by a hyaline capsule associated with the alteration of collagen fibers.

Azumiobodo hoyamushi, the kinetoplastid causing soft tunic syndrome in ascidians, may invade through the siphon wall.

The infectious kinetoplastid Azumiobodo hoyamushi causes 'soft tunic syndrome', a serious problem in aquaculture of the edible ascidian Halocynthia roretzi. Infection tests using diseased tunics demonstrated that juvenile (0.8 yr old) individuals never developed soft tunic syndrome, but all individuals in the other age groups (1.8, 2.8, and 3.8 yr old) showed the disease symptoms. In the infection tests, tunic softening was first observed at the tunic around siphons. Based on ultrastructural observation of the inner wall of the branchial siphon, the tunic lining the inner wall in juveniles (0.5 yr old) was completely covered with cuticle, which had a dense structure to prevent bacterial and protist invasion. In contrast, the tunic was often partly damaged and not covered with cuticle in healthy adults (≥2.5 yr old). The damaged tunic in the siphon wall could be an entrance for A. hoyamushi into the tunic of adult hosts.