A systematic survey of environmental DNA in Palau's lakes and waterfalls reveals an increase in Leptospira levels after flooding.

Objective: Leptospirosis is an important bacterial zoonosis which is widespread in tropical and subtropical islands and influences human and animal health which has secondary economic effects. Although leptospirosis is endemic in Palau, an Oceanian Pacific Island country, few systematic surveys of potential risk factors for Leptospira infection, such as weather and host animals, have been conducted in the natural environment. We used environmental DNA metabarcoding to assess the distribution, species diversity, and abundance of pathogenic Leptospira in this endemic region to investigate the potential environmental risks. Methods: Forty-two paired water samples, representing fine and rainy weather conditions, were collected from four representative waterfalls and lakes on Babeldaob Island, the largest island in Palau. High-throughput sequencing analysis was conducted for polymerase chain reaction products of leptospiral 16S rRNA and vertebrate animal mitochondrial 12S rRNA genes. Results: We revealed greater Leptospira diversity and abundance in samples collected after continuous rain, particularly in the presence of flooding, compared with samples collected under typhoon, monsoon, or fine weather conditions. From same samples, six mammalian species including cats (Felis catus), mice (Mus musculus), Yap flying fox (Pteropus yapensis), rats (Rattus spp.), and pigs (Sus scrofa) were repeatedly detected. These may be candidates of host animals of Leptospira in Palau; however, their detection was not clearly correlated with that of Leptospira. Conclusion: We repeatedly detected several species of pathogenic Leptospira from water samples of a wide region of Babeldaob Island. We confirmed that Leptospira contamination in freshwater environments increased under rainy conditions, particularly in the presence of flooding. This information could be used to improve public health control measures in this region.

Tissue-Targeted Transcriptomics Reveals SEMA3D Control of Hypoglossal Nerve Projection to Mouse Tongue Primordia.

The mouse hypoglossal nerve originates in the occipital motor nuclei at embryonic day (E)10.5 and projects a long distance, reaching the vicinity of the tongue primordia, the lateral lingual swellings, at E11.5. However, the details of how the hypoglossal nerve correctly projects to the primordia are poorly understood. To investigate the molecular basis of hypoglossal nerve elongation, we used a novel transcriptomic approach using the ROKU method. The ROKU algorithm identified 3825 genes specific for lateral lingual swellings at E11.5, of which 34 genes were predicted to be involved in axon guidance. Ingenuity Pathway Analysis-assisted enrichment revealed activation of the semaphorin signaling pathway during tongue development, and quantitative PCR showed that the expressions of Sema3d and Nrp1 in this pathway peaked at E11.5. Immunohistochemistry detected NRP1 in the hypoglossal nerve and SEMA3D as tiny granules in the extracellular space beneath the epithelium of the tongue primordia and in lateral and anterior regions of the mandibular arch. Fewer SEMA3D granules were localized around hypoglossal nerve axons and in the space where they elongated. In developing tongue primordia, tissue-specific regulation of SEMA3D might control the route of hypoglossal nerve projection via its repulsive effect on NRP1.

Habitual isomaltulose intake reduces arterial stiffness associated with postprandial hyperglycemia in middle-aged and elderly people: a randomized controlled trial.

Endothelin-1 (ET-1), produced by vascular endothelial cells, plays a pivotal role in the regulation of vascular tone. Isomaltulose, a naturally occurring sweetener and structural isomer of sucrose, reduces postprandial hyperglycemia, but its effect on arteriosclerosis due to hyperglycemia is unknown. The effects of 12 weeks of isomaltulose administration on ET-1 levels, a peptide that regulates arterial stiffness, blood pressure, and vascular tone, were tested before and after an oral glucose tolerance test. Fifty-four healthy middle-aged and older adults (30 men and 24 women) were divided into two groups: (1) a 25 g isomaltulose jelly drink intake group (Group I, 27 participants, mean age 55 ± 1 years) and (2) a sucrose jelly drink intake group (Group S, 27 participants, mean age 55 ± 1 years), each consuming isomaltulose or sucrose daily for 12 weeks, and a randomized, controlled study was conducted. Participants visited the laboratory before the intervention and 4, 8, and 12 weeks after the intervention to measure carotid-femoral (cf) and brachial-ankle (ba) pulse wave velocity (PWV), systolic blood pressure (BP), plasma glucose (PG), insulin, and ET-1 levels before and 60 and 120 min after a 75-g OGTT. baPWV, and ET-1 levels before intervention were significantly increased after 75-g OGTT compared to before 75-g OGTT in both groups (p < 0.05). The post-intervention baPWV, and ET-1 levels were significantly increased after 75-g OGTT in Group S compared to before 75-g OGTT (p < 0.05), whereas no significant changes were observed in Group I. These results suggest that consumption of isomaltulose, which has a lower GI than sucrose, is more effective in preventing the increases in systemic arterial stiffness associated with postprandial hyperglycemia in healthy middle-aged and older adults.

Feasibility of an Electronic Patient-Reported Outcome Tool for Screening Distress and Supportive Care Needs of Adolescents and Young Adults with Cancer.

Purpose: Although adolescent and young adult (AYA) cancer patients are digital natives and have high digital communication needs, previous studies of screening tools for AYAs have primarily used paper when measuring patient-reported outcomes (PROs). There are no reports on using an electronic PRO (ePRO) screening tool with AYAs. This study evaluated the feasibility of such a tool in clinical settings, and assessed the prevalence of AYAs' distress and supportive care needs. Methods: An ePRO tool based on the Distress Thermometer and Problem List (DTPL)-Japanese (DTPL-J) version for AYAs was implemented in a clinical setting for 3 months. To determine the prevalence of distress and need for supportive care, descriptive statistics were calculated for participant characteristics, selected items, and Distress Thermometer (DT) scores. Response rates, referral rates to an attending physician and other experts, and time required to complete PRO tools were assessed to evaluate feasibility. Results: From February to April 2022, 244 (93.8%) of 260 AYAs completed the ePRO tool based on the DTPL-J for AYAs. Based on a DT cutoff of ≥5, 65 of 244 patients (26.6%) had high distress. Worry (n = 81, 33.2%) was the most frequently selected item. Primary nurses referred 85 (32.7%) patients to an attending physician or other experts. The referral rate resulting from ePRO screening was significantly higher than that after PRO screening (χ2(1) = 17.99, p < 0.001). The average response time did not differ significantly between ePRO and PRO screening (p = 0.252). Conclusion: This study suggests the feasibility of an ePRO tool based on the DTPL-J for AYAs.

The relationship between Meckel's cartilage resorption and incisor tooth germ in mice.

Our understanding of the initiation and cellular mechanisms underlying endochondral resorption of Meckel's cartilage (MC) remains limited. Several studies have shown that the resorption site of MC and the mandibular incisor tooth germ are located close to each other. However, whether incisor tooth germ development is involved in MC resorption remains unclear. In this study, we aimed to elucidate the spatio-temporal interaction between the initiation site of MC resorption and the development of incisor tooth germs in an embryonic mouse model. To this effect, we developed a histology-based three-dimensional (3D) reconstruction technique using paraffin-embedded serial sections of various tissues in the jaw. The serial sections were cut in the frontal section and the tissue constituents (e.g., MC, incisor, and mineralized mandible) were studied using conventional and enzyme-based histochemistry. The outline of each component was marked on the frontal sectional images and 3D structures were constructed. To assess the vascular architecture at the site of MC resorption, immunohistochemical staining using anti-laminin, anti-factor VIII, and anti-VEGF antibodies was performed. MC resorption was first observed on the lateral incisor-facing side of the cartilage rods at sites anterior to the mental foramen on E16.0. The 3D analysis suggested that: (a) the posterior region of the clastic cartilage resorption corresponds to the cervical loop of the incisor; (b) the cervical portion of the tooth germ inflates probably due to temporal cellular congestion prior to differentiation into matrix-producing cells; (c) the incisor tooth germ tissue is present in close proximity to MC even in mouse with continuously growing tooth and determines the disappearance of MC as the tooth development.

Nuclear factor 1 X-type-associated regulation of myogenesis in developing mouse tongue.

OBJECTIVES: The tongue contains skeletal myofibers that differ from those in the trunk, limbs, and other orofacial muscles. However, the molecular basis of myogenic differentiation in the tongue muscles remains unclear. In this study, we conducted comprehensive gene expression profiling of the developing murine tongue. METHODS: Tongue primordia were dissected from mouse embryos at embryonic day (E)10.5-E18.5, while myogenic markers were detected via microarray analysis and quantitative polymerase chain reaction (PCR). In addition to common myogenic regulatory factors such as Myf5, MyoD, myogenin, and Mrf4, we focused on Nfix, which acts as a unique molecular switch triggering the shift from embryonic to fetal myoblast lineage during limb myogenesis. Nfix inhibition was performed using a specific antisense oligonucleotide in the organ culture of tongue primordia. RESULTS: Microarray and ingenuity pathway analyses confirmed the significant upregulation of myogenic signaling molecules, including Nfix, associated with the differentiation of myoblasts from myogenic progenitor cells during E10.5-E11.5. Quantitative PCR confirmed that Nfix expression started at E10.5 and peaked at E14.5. Fetal myoblast-specific genes, such as Mck and Myh8, were upregulated after E14.5, whereas embryonic myoblast-specific genes, such as Myh3 and Myh7, were downregulated. When Nfix was inhibited in the organ culture of tongue primordia, subtle morphological differences were noted in the tongue. Such an observation was only noted in the cultures of E10.5-derived tongue primordia. CONCLUSIONS: These results reveal the contribution of Nfix to tongue myogenesis. Nfix expression during early tongue development may play a vital role in tongue muscle development.

A practical protocol for high-spatial-resolution magnetic resonance angiography for cerebral arteries in rats.

BACKGROUND: Magnetic resonance angiography (MRA) is an important tool in rat models of cerebrovascular disease. Although MRA has long been used in rodents, the image quality is typically not as high as that observed in clinical practice. Moreover, studies on MRA image quality in rats are limited. This study aimed to develop a practical high-spatial-resolution MRA protocol for imaging cerebral arteries in rats. NEW METHOD: We used the "half position method" regarding coil placement and modified the imaging parameters and image reconstruction method. We applied this new imaging method to measure maturation-related signal changes on rat MRAs. RESULTS: The new practical high-spatial-resolution MRA imaging protocol obtained a signal intensity up to 3.5 times that obtained using a basic coil system, simply by modifying the coil placement method. This method allowed the detection of a gradual decrease in the signal in cerebral vessels with maturation. COMPARISON WITH EXISTING METHODS: A high-spatial-resolution MRA for rats was obtained with an imaging time of approximately 100 min. Comparable resolution and image quality were obtained using the new protocol with an imaging time of 30 min CONCLUSIONS: The new practical high-spatial-resolution MRA protocol can be implemented simply and successfully to achieve high image quality with an imaging time of approximately 30 min. This protocol will benefit researchers performing MRA imaging in cerebral artery studies in rats.

Painless thyroiditis mimicking relapse of hyperthyroidism during or after potassium iodide or thionamide therapy for Graves' disease resulting in remission.

The diagnosis of painless thyroiditis (PT) during antithyroid drug (ATD) treatment of Graves' disease (GD) is difficult. We evaluated the thyroidal radioactive iodine uptake (RAIU) in 100 patients with relapsed thyrotoxicosis during or after careful ATD treatment. The RAIU was <5%/5 h in 35 patients (35%) (Group A - PT), 5%-15%/5 h in 6 patients (6%) (Group B - indefinite) and >15%/5 h in 59 patients (59%) (Group C - relapsed GD [rGD]). TSH receptor antibody (TBII) was positive in 4 (11.4%), 3 (50.0%) and 39 (only 66.1%) patients in Groups A, B and C, respectively. In Group A, the serum fT4 level spontaneously normalized after 35 (26-56) days, sometimes followed by transient hypothyroidism, confirming the diagnosis of PT. Nineteen (54.3%) had been treated with potassium iodide, and PT frequently occurred ironically when the ATD dosage was reduced. PT repeatedly occurred in nine patients. All went into remission smoothly or developed hypothyroidism, except one patient with strongly positive TBII who developed rGD after the resolution of PT (PT on GD). In 10 (50%) of 20 patients with negative TBII despite rGD in Group C, TBII became positive afterwards. In conclusion, it is important to recognize that PT can occur in the clinical course of GD, resulting in frequent remission despite relapse of PT. The thyroid function reflects the balance between the stimulating TBII activity and the responsiveness of the thyroid tissue (sometimes unresponsive and other times autostimulated). The RAIU is still a valuable tool in cases of ambiguous thyrotoxicosis.

The relationship between social jetlag and subjective sleep quality: differences in young and middle-aged workers.

Social jetlag is a recent problem that is associated with a wide range of issues in the context of modern life. However, differences in the effects of social jetlag on sleep quality between young and middle-aged workers remain unclear. Accordingly, we aimed to examine the different effects of social jetlag on sleep quality in young (20-39 years) and middle-aged (40-59 years) workers from one factory. We included 106 male full-time workers (average age: 35.8 ± 11.5 years) who worked at the Kobe Factory of Fuji Electric Co., Ltd. Social jetlag was evaluated using the Munich ChronoType Questionnaire Japanese Version. Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index Japanese Version. Chronotype was determined using the Morningness-Eveningness Questionnaire Japanese Version (MEQ), while the health-related quality-of-life was evaluated using a revised version of the MOS 36-Item Short-Form Survey. Furthermore, we examined factors related to sleep quality in each age group using multiple regression analysis. Subjective sleep quality in the analysis set was poor; moreover, 39.4% of the participants had social jetlag for ≥ 1 h. Compared with middle-aged workers, young workers showed significantly longer and lower social jetlag and MEQ scores, respectively. Multiple regression analysis revealed that mental health and social jet lag were significantly associated with sleep quality in young participants. Contrastingly, social jetlag was not associated with sleep quality in middle-aged workers. Our findings demonstrate the importance of considering the effects of age-based factors on sleep quality.

Demonstration of aerosol profile measurement with a dual-wavelength high-spectral-resolution lidar using a scanning interferometer.

Simple dual-wavelength high-spectral-resolution lidar at 355 and 532 nm with a scanning interferometer was developed for continuous observations of aerosol profiles. Scanning the interferometer periodically over a range of one fringe at 532 nm (1.5 fringes at 355 nm) enabled recording of range-resolved interference signals at these two wavelengths. Reference signals taken from the transmitted laser were used to correct the interference phase shift due to laser frequency variation for every scan. Profiles of aerosol backscatter and extinction coefficients were retrieved from range-resolved interference data. One month of continuous measurements demonstrated the robustness of the system.

Lidar Ratio-Depolarization Ratio Relations of Atmospheric Dust Aerosols: The Super-Spheroid Model and High Spectral Resolution Lidar Observations.

The backscattering optical properties of an ensemble of randomly oriented dust particles at a wavelength of 355 nm were comprehensively studied by examining the invariant imbedding T-matrix results of the super-spheroid dust model. In particular, we focused on the lidar ratio ( S ) and depolarization ratio ( δ ) relations of dust aerosols to aid interpretation of data from the Atmospheric Lidar (ATLID) instrument that will be onboard the Earth Cloud, Aerosol and Radiation Explorer (EarthCARE) satellite. Super-spheroid models with various aspect ratios ( α ), roundness parameters ( n ) , and refractive indices were investigated over a wide range of particle sizes and compared to the observation data of the National Aeronautics and Space Administration (NASA) Langley 355-nm airborne high spectral resolution lidar. We found that super-spheroid dust particles with different sets of n and α could be used to model almost the entire range of the observed joint distributions of S and δ . The S - δ relation could effectively discriminate among dust particle types. The observed S and δ values with the largest population density were best covered by models with n > 2, especially by those with n varying from 2.4 to 3.0.

An isogenic panel of App knock-in mouse models: Profiling ß-secretase inhibition and endosomal abnormalities.

We previously developed single App knock-in mouse models of Alzheimer's disease (AD) that harbor the Swedish and Beyreuther/Iberian mutations with or without the Arctic mutation (AppNL-G-F and AppNL-F mice). We have now generated App knock-in mice devoid of the Swedish mutations (AppG-F mice) and evaluated its characteristics. Amyloid ß peptide (Aß) pathology was exhibited by AppG-F mice from 6 to 8 months of age and was accompanied by neuroinflammation. Aß-secretase inhibitor, verubecestat, attenuated Aß production in AppG-F mice, but not in AppNL-G-F mice, indicating that the AppG-F mice are more suitable for preclinical studies of ß-secretase inhibition given that most patients with AD do not carry the Swedish mutations. Comparison of isogenic App knock-in lines revealed that multiple factors, including elevated C-terminal fragment ß (CTF-ß) and humanization of Aß might influence endosomal alterations in vivo. Thus, experimental comparisons between different isogenic App, knock-in mouse lines will provide previously unidentified insights into our understanding of the etiology of AD.

Mouse models of Alzheimer's disease for preclinical research.

Most mouse models for preclinical research into Alzheimer's disease (AD) rely on the overexpression paradigm, in which familial AD (FAD)-related genes linked to amyloid precursor protein (APP) and presenilin-1 (PSEN1) are overexpressed. Such mice have been used for over two decades as the first-generation transgenic lines for AD, with animals exhibiting AD pathologies along with additional phenotypes, leading to the serious artifacts. To overcome the intrinsic drawbacks of the overexpression paradigm, we previously developed second-generation mouse models that incorporate humanized amyloid ß (Aß) sequences and several FAD-related mutations on the mouse endogenous App gene. Such models show AD pathologies in an age-dependent manner. In addition, our group recently generated additional lines of mice harboring multiple mutations without gene overexpression; these third-generation models exhibit an accelerated AD pathology compared to earlier generations. In this review, we describe the development and future prospects of AD mouse models in terms of their scientific properties and therapeutic perspectives in the context of the preclinical study of AD.

Recent Advances in the Modeling of Alzheimer's Disease.

Since 1995, more than 100 transgenic (Tg) mouse models of Alzheimer's disease (AD) have been generated in which mutant amyloid precursor protein (APP) or APP/presenilin 1 (PS1) cDNA is overexpressed ( 1st generation models ). Although many of these models successfully recapitulate major pathological hallmarks of the disease such as amyloid ß peptide (Aß) deposition and neuroinflammation, they have suffered from artificial phenotypes in the form of overproduced or mislocalized APP/PS1 and their functional fragments, as well as calpastatin deficiency-induced early lethality, calpain activation, neuronal cell death without tau pathology, endoplasmic reticulum stresses, and inflammasome involvement. Such artifacts bring two important uncertainties into play, these being (1) why the artifacts arise, and (2) how they affect the interpretation of experimental results. In addition, destruction of endogenous gene loci in some Tg lines by transgenes has been reported. To overcome these concerns, single App knock-in mouse models harboring the Swedish and Beyreuther/Iberian mutations with or without the Arctic mutation (AppNL-G-F and AppNL-F mice) were developed ( 2nd generation models ). While these models are interesting given that they exhibit Aß pathology, neuroinflammation, and cognitive impairment in an age-dependent manner, the model with the Artic mutation, which exhibits an extensive pathology as early as 6 months of age, is not suitable for investigating Aß metabolism and clearance because the Aß in this model is resistant to proteolytic degradation and is therefore prone to aggregation. Moreover, it cannot be used for preclinical immunotherapy studies owing to the discrete affinity it shows for anti-Aß antibodies. The weakness of the latter model (without the Arctic mutation) is that the pathology may require up to 18 months before it becomes sufficiently apparent for experimental investigation. Nevertheless, this model was successfully applied to modulating Aß pathology by genome editing, to revealing the differential roles of neprilysin and insulin-degrading enzyme in Aß metabolism, and to identifying somatostatin receptor subtypes involved in Aß degradation by neprilysin. In addition to discussing these issues, we also provide here a technical guide for the application of App knock-in mice to AD research. Subsequently, a new double knock-in line carrying the AppNL-F and Psen1 P117L/WT mutations was generated, the pathogenic effect of which was found to be synergistic. A characteristic of this 3rd generation model is that it exhibits more cored plaque pathology and neuroinflammation than the AppNL-G-F line, and thus is more suitable for preclinical studies of disease-modifying medications targeting Aß. Furthermore, a derivative AppG-F line devoid of Swedish mutations which can be utilized for preclinical studies of ß-secretase modifier(s) was recently created. In addition, we introduce a new model of cerebral amyloid angiopathy that may be useful for analyzing amyloid-related imaging abnormalities that can be caused by anti-Aß immunotherapy. Use of the App knock-in mice also led to identification of the α-endosulfine-K ATP channel pathway as components of the somatostatin-evoked physiological mechanisms that reduce Aß deposition via the activation of neprilysin. Such advances have provided new insights for the prevention and treatment of preclinical AD. Because tau pathology plays an essential role in AD pathogenesis, knock-in mice with human tau wherein the entire murine Mapt gene has been humanized were generated. Using these mice, the carboxy-terminal PDZ ligand of neuronal nitric oxide synthase (CAPON) was discovered as a mediator linking tau pathology to neurodegeneration and showed that tau humanization promoted pathological tau propagation. Finally, we describe and discuss the current status of mutant human tau knock-in mice and a non-human primate model of AD that we have successfully created.

Iodide-sensitive Graves' hyperthyroidism and the strategy for resistant or escaped patients during potassium iodide treatment.

The effectiveness of potassium iodide (KI) (100 mg/day) was evaluated in 504 untreated patients with Graves' hyperthyroidism (GD). Initial response to KI within 180 days, the effect of additional methylmercaptoimidazole (MMI) or radioactive iodine (RI) in resistant or escaped patients, and long-term prognosis were evaluated. Serum fT4 levels became low or normal in 422 patients (83.7%, KI-sensitive group) without serious side effects. Among these patients, serum TSH levels became high (n = 92, hypothyroid) or normal (n = 78) in 170 patients (33.7%) (KI-sensitive with a recovered TSH response, Group A), but remained suppressed in 252 patients (50.0%) (KI-sensitive with TSH suppression, Group B). Serum fT4 levels decreased but remained high in 82 patients (16.3%) (KI-resistant, Group C). Older patients, or those with small goiter and mild GD were more KI-sensitive with a recovered TSH response than others. Escape from KI effect occurred in 0%, 36% and 82% in Group A, B and C, respectively. Patients in Group B and C were successfully treated with additional low-dosage MMI or RI. After 2-23 years' treatment (n = 429), remission (including possible remission) and spontaneous hypothyroidism were significantly more frequent in Group A (74.3% and 11.1%, respectively,) than in Groups B (46.3% and 2.8%, respectively) or C (53.6% and 1.5%, respectively) (p < 0.0001). In conclusion, a high KI sensitivity with a recovered TSH response was observed in about a third of the patients in GD associated with a better prognosis. Additional MMI or RI therapy was effective in escaped or KI-resistant patients with suppressed TSH level.

A case of Graves' disease presenting with internal ophthalmoplegia during methylmercaptoimidazole treatment.

A 28-year-old Japanese woman positive for TSH receptor antibody and anti-nuclear antibody complained of difficulty seeing nearby objects, severe throbbing retro-orbital pain, diplopia, blepharoptosis and upward gaze palsy when she became hypothyroid during treatment with 30 mg methylmercaptoimidazole for Graves' hyperthyroidism. Brain magnetic resonance imaging revealed slightly swollen bilateral inferior rectus muscles, suggesting the external ophthalmoplegia due to the muscle pathology commonly encountered in Graves' disease. The retro-orbital pain was associated with marked accommodation failure and the pupillary abnormalities. The left and/or right eye showed intermittent, asymmetric and fluctuating mydriasis, being unresponsive to ordinary light but slowly responsive to strong sunlight and slowly responsive in a dark room. During the 5-year period, mydriasis was observed 9 times on both sides, 11 times only on the right side and 4 times only on the left side. Internal ophthalmoplegia with tonic pupils and accommodation failure affecting both the pupillary sphincter muscle and ciliary muscle due to damage to the parasympathetic outflow to these muscles was suggested. Autoimmune mechanism and/or the mechanism underlying channelopathy affecting the ciliary ganglion or short ciliary nerves might be responsible for this fluctuating complication. This very rare panophthalmopathy affecting both external and internal muscles occurred when the patient was suffering from iatrogenic hypothyroidism during the 30 mg methylmercaptimidazole treatment for Graves' disease.

A third-generation mouse model of Alzheimer's disease shows early and increased cored plaque pathology composed of wild-type human amyloid ß peptide.

We previously developed single App knock-in mouse models of Alzheimer's disease (AD) harboring the Swedish and Beyreuther/Iberian mutations with or without the Arctic mutation (AppNL-G-F and AppNL-F mice, respectively). These models showed Aß pathology, neuroinflammation, and cognitive impairment in an age-dependent manner. The former model exhibits extensive pathology as early as 6 months, but is unsuitable for investigating Aß metabolism and clearance because the Arctic mutation renders Aß resistant to proteolytic degradation and prone to aggregation. In particular, it is inapplicable to preclinical immunotherapy studies due to its discrete affinity for anti-Aß antibodies. The latter model may take as long as 18 months for the pathology to become prominent, which leaves an unfulfilled need for an Alzheimer's disease animal model that is both swift to show pathology and useful for antibody therapy. We thus utilized mutant Psen1 knock-in mice into which a pathogenic mutation (P117L) had been introduced to generate a new model that exhibits early deposition of wild-type human Aß by crossbreeding the AppNL-F line with the Psen1P117L/WT line. We show that the effects of the pathogenic mutations in the App and Psen1 genes are additive or synergistic. This new third-generation mouse model showed more cored plaque pathology and neuroinflammation than AppNL-G-F mice and will help accelerate the development of disease-modifying therapies to treat preclinical AD.

Alternative reproductive tactics in male freshwater fish influence the accuracy of species recognition.

Sexual conflict can result in coercive mating. Because males bear low costs of heterospecific mating, coercive males may engage in misdirected mating attempts toward heterospecific females. In contrast, sexual selection through consensual mate choice can cause mate recognition cues among species to diverge, leading to more accurate species recognition. Some species show both coercive mating and mate choice-associated courtship behaviors as male alternative reproductive tactics. We hypothesized that if the selection pressures on each tactic differ, then the accuracy of species recognition would also change depending on the mating tactic adopted. We tested this hypothesis in the guppy (Poecilia reticulata) and mosquitofish (Gambusia affinis) by a series of choice experiments. Poecilia reticulata and G. affinis males both showed imperfect species recognition and directed all components of mating behavior toward heterospecific females. They tended to direct courtship displays more frequently toward conspecific than heterospecific females. With male P. reticulata, however, accurate species recognition disappeared when they attempted coercive copulation: they directed coercions more frequently toward heterospecific females. We also found that heterospecific sexual interaction had little effect on the fecundity of gravid females, which suggests that prepregnancy interactions likely underpin the exclusion of G. affinis by P. reticulata in our region.

Female Marking via Rubidium-Labeled Ejaculates in the West Indian Sweetpotato Weevil (Coleoptera: Curculionidae).

The West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire), is one of the pests of the sweet potato, Ipomoea batatas, in tropical and subtropical countries. Although an eradication program using the sterile insect technique (SIT) for this weevil is now underway in Japan, the lack of potent attractants such as sex pheromones for this weevil species prevents effective monitoring and hampers pest control operations. New methods to monitor the performance of sterile males using trapped wild females are needed. In this study, we tested whether the ejaculate of the labeled males that were fed an artificial diet labeled with the trace element, rubidium (Rb), is detectable in the fertilized females. We fed an artificial diet treated with Rb (1.00, 0.50, 0.25, and 0.00%) to adult male weevils for 14 d after emerging and quantified the rubidium content in inseminated females. We also examined the side effects of the artificial diet on mating performance and longevity. The advantages of monitoring the spatial level of sterility using data from females labeled with ejaculate of Rb-fed males in an SIT eradication program are discussed.

Population genetic structure and evolution of Batesian mimicry in Papilio polytes from the Ryukyu Islands, Japan, analyzed by genotyping-by-sequencing.

Batesian mimicry is a striking example of Darwinian evolution, in which a mimetic species resembles toxic or unpalatable model species, thereby receiving protection from predators. In some species exhibiting Batesian mimicry, nonmimetic individuals coexist as polymorphism in the same population despite the benefits of mimicry. In a previous study, we proposed that the abundance of mimics is limited by that of the models, leading to polymorphic Batesian mimicry in the swallowtail butterfly, Papilio polytes, on the Ryukyu Islands in Japan. We found that their mimic ratios (MRs), which varied among the Islands, were explained by the model abundance of each habitat, rather than isolation by distance or phylogenetic constraint based on the mitochondrial DNA (mtDNA) analysis. In the present study, this possibility was reexamined based on hundreds of nuclear single nucleotide polymorphisms (SNPs) of 93 P. polytes individuals from five Islands of the Ryukyus. We found that the population genetic and phylogenetic structures of P. polytes largely corresponded to the geographic arrangement of the habitat Islands, and the genetic distances among island populations show significant correlation with the geographic distances, which was not evident by the mtDNA-based analysis. A partial Mantel test controlling for the present SNP-based genetic distances revealed that the MRs of P. polytes were strongly correlated with the model abundance of each island, implying that negative frequency-dependent selection interacting with model species shaped and maintained the mimetic polymorphism. Taken together, our results support the possibility that predation pressure, not isolation by distance or other neutral factors, is a major driving force of evolution of the Batesian mimicry in P. polytes from the Ryukyus.