Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 203
Filtrar
1.
Sci Rep ; 11(1): 7929, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33846449

RESUMO

The emergence of drug-resistant bacteria has become a major problem worldwide. Bacterial dipeptidyl peptidases 7 and 11 (DPP7s and DPP11s), belonging to the family-S46 peptidases, are important enzymes for bacterial growth and are not present in mammals. Therefore, specific inhibitors for these peptidases are promising as potential antibiotics. While the molecular mechanisms underlining strict specificity at the S1 subsite of S46 peptidases have been well studied, those of relatively broad preference at the S2 subsite of these peptidases are unknown. In this study, we performed structural and biochemical analyses on DPP7 from Stenotrophomonas maltophilia (SmDPP7). SmDPP7 showed preference for the accommodation of hydrophobic amino acids at the S2 subsite in general, but as an exception, also for asparagine, a hydrophilic amino acid. Structural analyses of SmDPP7 revealed that this exceptional preference to asparagine is caused by a hydrogen bonding network at the bottom of the S2 subsite. The residues in the S2 subsite are well conserved among S46 peptidases as compared with those in the S1 subsite. We expect that our findings will contribute toward the development of a universal inhibitor of S46 peptidases.

2.
J Infect Chemother ; 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33745812

RESUMO

INTRODUCTION: Rapid detection of Shiga toxin-producing Escherichia coli (STEC) is essential. Matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid, accurate, and low-cost microbial identification. We aimed to examine the discrimination ability of MALDI Biotyper (Bruker Daltonics) between STEC and non-STEC. METHODS: In total, 234 strains (79 STEC strains and 155 non-STEC strains) isolated from stool between 2009 and 2014 were measured by MALDI Biotyper and mass spectra of 2000-20,000 m/z were analyzed with ClinProTools (Bruker Daltonics). Eighty-three strains were randomly extracted to produce STEC detection models using 3 algorithms, and 151 strains were used as validation samples to verify STEC detection performance and discrimination performance of Shiga toxins with the STEC detection models. RESULTS: The STEC detection model with Quick Classifier (QC) algorithm was the most sensitive: sensitivity, 84.1% (37/44); specificity, 94.4% (101/107). Discrimination between STEC and non-STEC was excellent, but individual discrimination of Shiga toxins was not possible. CONCLUSION: MALDI Biotyper may be a useful rapid diagnostic method for STEC infection.

3.
Fukushima J Med Sci ; 67(1): 27-32, 2021 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-33642419

RESUMO

Of the 47 prefectures in Japan, Iwate had the fewest cases of coronavirus disease 2019 (COVID-19), with the first diagnosis officially confirmed on July 28, 2020. A baseline serological survey of COVID-19 antibodies is essential to accurately evaluate an epidemic outbreak. The primary purpose of this study was to determine pre-epidemic prevalence of COVID-19 antibodies among healthcare workers, using two laboratory-based quantitative tests. In addition, a point-of-care (POC) qualitative test, rapid, simple, and convenient for primary care clinics, was compared with the laboratory-based tests. All antibody tests were performed on serum from 1,000 healthcare workers (mean age, 40 ± 11 years) in Iwate Prefectural Central Hospital, May 29-31, 2020. A COVID-19 case was defined as showing positive results in both laboratory-based quantitative tests. None of 1,000 samples had positive results in both of the laboratory immunoassays. The POC test showed positive results in 33 of 1,000 samples (3.3%) (95% confidence interval:2.19-4.41), but no samples were simultaneously positive in both laboratory-based tests. In conclusion, COVID-19 cases were not serologically confirmed by a baseline control study of healthcare workers at our hospital in late May, 2020. Moreover, the POC qualitative test may offer no advantage in areas with very low prevalence of COVID-19, due to higher false-positive reactions compared with laboratory-based quantitative immunoassays.

4.
J Med Virol ; 2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33760273

RESUMO

The polymerase chain reaction (PCR) testing rate is low in our local area and the true rate of coronavirus disease 2019 (COVID-19) infection may include many asymptomatic individuals. We conducted a serosurveillance using antibody testing in an area where official report of COVID-19 infection is not done yet. Blood samples were obtained from 1404 healthcare workers (41 ± 11 years) in our hospital on May 29-31, 2020. First, the potential infection frequency was confirmed using two quantitative antibody tests. In addition, the usefulness of rapid antibody kit testing for COVID-19 serosurveillance was examined. A COVID-19-indected case was defined as showing positive results in both quantitative tests. None of 1404 samples had positive results from the two quantitative tests. The false positive rates were 0.36% and 0.07%, whereas those in rapid antibody kits were 3.3% and 3.0%. In conclusion, as of May, 2020, potential spread mainly by asymptomatic individuals infected with COVID-19 was not found in our local area where there was no official report of COVID-19, even if the PCR testing rate was low. Rapid antibody kits might not be useful due to the high false positive rate in an area with a low incidence of COVID-19 infected individuals.

5.
Int J Mol Sci ; 22(5)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33669048

RESUMO

Diabetic neuropathy is one of the most common complications of diabetes. This complication is peripheral neuropathy with predominant sensory impairment, and its symptoms begin with hyperesthesia and pain and gradually become hypoesthesia with the loss of nerve fibers. In some cases, lower limb amputation occurs when hypoalgesia makes it impossible to be aware of trauma or mechanical stimuli. On the other hand, up to 50% of these complications are asymptomatic and tend to delay early detection. Therefore, sensitive and reliable biomarkers for diabetic neuropathy are needed for an early diagnosis of this condition. This review focuses on systemic biomarkers that may be useful at this time. It also describes research on the relationship between target gene polymorphisms and pathological conditions. Finally, we also introduce current information on regenerative therapy, which is expected to be a therapeutic approach when the pathological condition has progressed and nerve degeneration has been completed.

6.
Med Mycol ; 59(3): 289-295, 2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33539539

RESUMO

An efficacious period of two topical antifungal drugs was compared in a Trichophyton mentagrophytes-infected onychomycosis model in guinea pigs treated with antifungal drugs prior to infection. Luliconazole 5% (LLCZ) and efinaconazole 10% (EFCZ) test solutions were applied to the animals' nails once daily for 2 weeks followed by a nontreatment period of 2, 4, and 8 weeks. After each nontreatment period, the nails were artificially infected by the fungus. Drug efficacy was quantitatively evaluated by qPCR and histopathological examination of the nails collected following a 4-week post-infection period. The fungal infection was confirmed in the untreated group. Both LLCZ and EFCZ prevented fungal infection in the treated groups with the nontreatment period of 2 weeks. After the nontreatment period of 4 weeks, no infection was observed in the LLCZ-treated group; however, infection into the nail surface and fungal invasion into the nail bed were observed in the EFCZ-treated group. After the nontreatment period of 8 weeks, fungi were found in the nail surface and nail bed in some nails treated with EFCZ; however, no infection was observed in the nail bed of the LLCZ-treated group. The results suggest that LLCZ possesses longer-lasting antifungal effect in nails of the guinea pigs than EFCZ, and that this animal model could be useful for translational research between preclinical and clinical studies to evaluate the pharmacological efficacy of antifungal drugs to treat onychomycosis. This experimentally shown longer-lasting preventive effects of LLCZ could also decrease the likelihoods of onychomycosis recurrence clinically.

7.
Semin Immunopathol ; 43(2): 245-253, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33532928

RESUMO

The strong association of HLA-B*27 with ankylosing spondylitis (AS) was first reported nearly 50 years ago. However, the mechanistic link between HLA-B*27 and AS has remained an enigma. While 85-90% of AS patients possess HLA-B*27, majority of HLA-B*27 healthy individuals do not develop AS. This suggests that additional genes and genetic regions interplay with HLA-B*27 to cause AS. Previous genome-wide association studies (GWAS) identified key genes that are distinctively expressed in AS, including the Endoplasmic Reticulum Aminopeptidase (ERAP) 1 and ERAP2. As these gene-encoding molecules are primarily implicated in the process of peptide processing and presentation, potential pathological interaction of these molecules with HLA-B*27 may operate to cause AS by activating downstream immune responses. The aberrant peptide processing also gives rise to the accumulation of unstable protein complex in endoplasmic reticulum (ER), which drives endoplasmic reticulum-associated protein degradation (ERAD) and unfolded protein response (UPR) and activates autophagy. In this review, we describe the current hypotheses of AS pathogenesis, focusing on antigen processing and presentation operated by HLA-B*27 and associated molecules that may contribute to the disease initiation and progression of AS.

8.
In Vivo ; 35(1): 555-561, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33402509

RESUMO

BACKGROUND/AIM: Perforation and postoperative complications have a negative effect on long-term outcomes in patients with colorectal cancer (CRC). The aim of this study was to evaluate the clinical factors with special reference to postoperative complications predicting the long-term outcome in those for whom curative resection for perforated CRC was performed. PATIENTS AND METHODS: Patients who underwent curative resection for perforated CRC at stage II or III from April 2003 to March 2020 were included. Clinical factors were retrospectively analyzed. RESULTS: Forty-four patients met the selection criteria. The 30-day mortality rate was 4.5% and the complication rate was 47.7%. Excluding 30-day mortality, five-year recurrence-free survival (RFS) and overall survival (OS) were 62.3% and 73.6%, respectively. Multivariate analysis showed that postoperative complications (p=0.005) and pT4 pathological factor (p=0.009) were independent prognostic factors for RFS. Only postoperative complications (p=0.023) were an independent prognostic factor for OS. CONCLUSION: Postoperative complications were significantly associated with RFS and OS, and pT4 was associated with RFS. The prevention and management of postoperative adverse events may be important for perforated CRC.

9.
J Clin Lab Anal ; 35(3): e23698, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33426721

RESUMO

BACKGROUND: To help combat the worldwide spread of multidrug-resistant Enterobacterales, which are responsible for many causes of urinary tract infection (UTI), we evaluated the ability of the Atellica UAS800 automated microscopy system, the only one offering the capability of bacterial morphological differentiation, to determine its effectiveness. METHODS: We examined 118 outpatient spot urine samples in which pyuria and bacteriuria were observed using flow cytometry (training set: 81; cross-validation set: 37). The ability of the Atellica UAS800 to differentiate between bacilli and cocci was verified. To improve its ability, multiple logistic regression analysis was used to construct a prediction formula. RESULTS: This instrument's detection sensitivity was 106 CFU/ml, and reproducibility in that range was good, but data reliability for the number of cocci was low. Multiple logistic regression analysis with each explanatory variable (14 items from the Atellica UAS800, age and sex) showed the best prediction formula for discrimination of uropathogen morphology was a model with 5 explanatory variables: number of bacilli (p < 0.001), squamous epithelial cells (p = 0.004), age (p = 0.039), number of cocci (p = 0.107), and erythrocytes (p = 0.111). For a predicted cutoff value of 0.449, sensitivity was 0.879 and specificity was 0.854. In the cross-validation set, sensitivity was 0.813 and specificity was 0.857. CONCLUSIONS: The Atellica UAS800 could detect squamous epithelial cells, an indicator of vaginal contamination, with high sensitivity, which further improved performance. Simultaneous use of this probability prediction formula with urinalysis results may facilitate real-time prediction of uropathogens and vaginal contamination, thus providing helpful information for empiric therapy.

10.
Carbohydr Polym ; 254: 117252, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357848

RESUMO

The green alga Parachlorella sp. BX1.5 is a new strain that can significantly coproduce lipids and polysaccharides, inside and outside the cells, respectively. This study aimed to investigate the characteristics and functional properties of the extracellular polysaccharide (EPS). Ethanol-extracted EPS from the cells grown in N-starved BG11 medium was found to be a novel acidic rhamnan of straight-chain type, with a high molecular mass of > 1.75 × 106 daltons. The water-soluble EPS exhibited high viscosity as sol, even at low concentrations, with 0.5 % EPS showing almost constant viscosity at 10-40 °C. Its addition to mayonnaise resulted in improved oil-off, suggesting its possible application as a thickener or food additive. Cells with added EPS were found to exhibit resistance to environmental stress conditions, such as heat, dryness, and decompression, and ultraviolet rays. Based on these rheological and biological effects, its unique properties with respect to biorefinery have been discussed here.


Assuntos
Clorófitas/química , Polissacarídeos/química , Emulsões , Matriz Extracelular de Substâncias Poliméricas/química , Aditivos Alimentares/química , Aditivos Alimentares/isolamento & purificação , Aditivos Alimentares/farmacologia , Microscopia de Força Atômica , Estrutura Molecular , Peso Molecular , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade
11.
Chaos ; 30(11): 113140, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33261318

RESUMO

Postural instability is one of the major symptoms of Parkinson's disease. Here, we assimilated a model of intermittent delay feedback control during quiet standing into postural sway data from healthy young and elderly individuals as well as patients with Parkinson's disease to elucidate the possible mechanisms of instability. Specifically, we estimated the joint probability distribution of a set of parameters in the model using the Bayesian parameter inference such that the model with the inferred parameters can best-fit sway data for each individual. It was expected that the parameter values for three populations would distribute differently in the parameter space depending on their balance capability. Because the intermittent control model is parameterized by a parameter associated with the degree of intermittency in the control, it can represent not only the intermittent model but also the traditional continuous control model with no intermittency. We showed that the inferred parameter values for the three groups of individuals are classified into two major groups in the parameter space: one represents the intermittent control mostly for healthy people and patients with mild postural symptoms and the other the continuous control mostly for some elderly and patients with severe postural symptoms. The results of this study may be interpreted by postulating that increased postural instability in most Parkinson's patients and some elderly persons might be characterized as a dynamical disease.

12.
Yakugaku Zasshi ; 140(12): 1441-1454, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-33268686

RESUMO

A requirement, which students must satisfy, for a diploma at the Showa University School of Pharmacy is the ability to "plan, practice, and assess pharmacotherapy". To continuously assess the ability of students to meet this requirement and to provide patients with proper pharmacotherapy during student clinical rotations, we formulated the "Rubric assessment for pharmacotherapy" and evaluated its usefulness in tutorial learning classes. Clinical pharmacy faculty members created the rubric based on the Subjective, Objective, Assessment, and Plan (SOAP) note guidelines of the university. Third- (2016) and fourth-year students (2017) were required to self-assess their SOAP notes to analyze six clinical cases using the rubric. The rubric consists of three domains: (1) Evaluation of patient condition, (2) Proposal of pharmacotherapy, and (3) Plan for an assessment of pharmacotherapy. The rubric comprises 31 subdomains and is evaluated according to four levels of performance. In this study, 978 rubric sheets that were used by students to evaluate their own SOAP notes were analyzed. We found that the students were able to continuously self-assess their performance using the rubric while continuously improving their achievement level (p<0.05). The results of this study suggest that rubric assessments may be used as a tool for supporting students to plan, practice, and assess pharmacotherapy.

13.
Kyobu Geka ; 73(12): 1002-1005, 2020 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-33268750

RESUMO

Extrapleural hematoma caused by thoracic vertebral burst fracture is very rare. We present the case of a 70-year-old man who was treated with a combination of video-assisted thoracic surgery (VATS) and extrathoracic operation. The patient was admitted to our hospital with complaints of dyspnea and pain in both legs. Computed tomography (CT) demonstrated a massive extrapleural hematoma in the right thoracic cavity, and 12th thoracic vertebral burst fracture. We treated the patient with pharmacotherapy because CT showed no active bleeding and the circulation and respiratory dynamics were stable. One week later, the hematoma was not reduced by pharmacotherapy, so we performed combination surgery of VATS. After surgery, there were no serious complications and the patient was discharged from the hospital on day 11 from surgery. In the following 2 months, there was no evidence of recurrence. The combination of VATS and extrathoracic operation was safe, and good result was obtained.

14.
J Pharm Health Care Sci ; 6(1): 25, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-33292643

RESUMO

BACKGROUND: Xanthan gum-based food thickeners (XG-FTs) are often ingested by patients with dysphagia to prevent aspiration during drug treatment. Reportedly, XG-FTs affect tablet disintegration, drug dissolution rates, and reduce the efficacy of postprandial antihyperglycemic agents. The absorption rate and quantity of fluoroquinolone antimicrobial agents correlate with drug efficacy, raising concern about the impact of XG-FTs. Previously, we reported that film-coated tablets were less susceptible to the effects of XG-FT than conventional and orally disintegrating tablets. Here, we compare the effect of XG-FTs on dissolution profiles of three oral fluoroquinolone-based film-coated tablets by evaluating the dissolution of crushed products, fine granules, and film-coated fine granules. METHODS: We examined formulations of tosufloxacin tosylate monohydrate (TFLX), levofloxacin hemihydrate (LVFX), and ciprofloxacin hydrochloride hydrate (CPFX). The formulations were immersed in 20 mL of 1.5% (w/v) XG-FT aqueous solution for 2.5 min followed by a dissolution test using the paddle method according to the Japanese Pharmacopoeia (dissolution test solution pH 1.2; volume 900 mL; temperature 37 ± 0.5 °C). The dissolution profile was evaluated according to the dissolution quantity indicated in product specifications and guidelines for bioequivalence testing of generic drugs. The 15-min mean dissolution rate was determined for a formulation immersed in 1.5% (w/v) XG-FT aqueous solution and compared with that for a non-immersed formulation (control). Fluoroquinolone film-coated tablets were mixed with starch-based FTs, guar gum-based FTs, or XG-FTs to observe their appearances. RESULTS: The dissolution profile of LVFX film-coated tablets was not affected by XG-FTs, but the dissolution of TFLX and CPFX was delayed. For crushed film-coated tablets, the 15-min mean dissolution rate was significantly delayed for all three fluoroquinolones when compared with that of uncrushed products. The dissolution profile of TFLX film-coated fine granules was unchanged by XG-FTs. CPFX film-coated tablets and crushed products produced a gel-like precipitate when mixed with XG-FTs and failed to meet product-dissolution specifications. A gel-like precipitate was also observed with guar gum-based FTs. CONCLUSION: The effect of XG-FTs on the dissolution profile of film-coated fluoroquinolone formulations varied depending on the formulation. The CPFX formulation formed a gel-like precipitate when immersed in XG-FTs resulting in a significantly delayed dissolution.

15.
Kyobu Geka ; 73(13): 1076-1079, 2020 Dec.
Artigo em Japonês | MEDLINE | ID: mdl-33271575

RESUMO

Solitary diaphragmatic metastasis from early endometrial cancer is quite rare. We present a case of a 58-year-old woman who had been performed radical surgery for stageⅠA, G1 endometrial cancer 3 years before. The patient was referred to our hospital for chest abnormal shadow. Computed tomography (CT) and Magnetic resonance imaging (MRI) showed a mass in the right diaphragm, without the finding of liver invasion. We performed partial resection of diaphragm through video-assisted thoracoscopic surgery (VATS). After surgery, there were no serious complications and was discharged from the hospital on day 6 from surgery. Nine months later, the patient is alive without recurrence.

16.
Int J Mol Sci ; 21(22)2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33227981

RESUMO

Hermaphroditic invertebrates and plants have a self-recognition system on the cell surface of sperm and eggs, which prevents their self-fusion and enhances non-self-fusion, thereby contributing to genetic variation. However, the system of sperm-egg recognition in mammals is under debate. To address this issue, we explored the role of major histocompatibility complex class I (MHC class I, also known as histocompatibility 2-Kb or H2-Kb and H2-Db in mice) antigens by analyzing H2-Kb-/-H2-Db-/-ß2-microglobulin (ß2M)-/- triple-knockout (T-KO) male mice with full fertility. T-KO sperm exhibited an increased sperm number in the perivitelline space of wild-type (WT) eggs in vitro. Moreover, T-KO sperm showed multiple fusion with zona pellucida (ZP)-free WT eggs, implying that the ability of polyspermy block for sperm from T-KO males was weakened in WT eggs. When T-KO male mice were intercrossed with WT female mice, the percentage of females in progeny increased. We speculate that WT eggs prefer fusion with T-KO sperm, more specifically X-chromosome-bearing sperm (X sperm), suggesting the presence of preferential (non-random) fertilization in mammals, including humans.

17.
Int J Surg Case Rep ; 77: 279-283, 2020 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-33189011

RESUMO

INTRODUCTION: Lung cancer is one of the most common cancers. On the other hand, lung cancer metastasis to the appendix is extremely rare, and in many cases it has been diagnosed with the onset of acute perforating appendicitis. PRESENTATION OF CASE: An 85-year-old man with fever and abdominal pain visited our hospital. He had a history of squamous cell carcinoma of the left upper and lower lobes, metastasis to the ipsilateral lung and femur. CT showed that a finding of acute perforating appendicitis, emergency cecal resection was performed. Examination of the resected specimen showed that the appendix was thickened overall, with a white nodular structure at the root and a perforation in the middle. The final diagnosis was acute perforating appendicitis caused by metastatic squamous cell carcinoma from the lung. The patient had no particular problems during the postoperative course. DISCUSSION: A PubMed search was performed, this appears to be the first reported case of appendiceal metastasis of squamous cell carcinoma of the lung. Since squamous cell carcinoma of the lung has a stronger tendency for local extension than other histological types, perforating appendicitis due to distant metastasis to the abdominal organs and metastasis to the appendix was reported as a very valuable case. CONCLUSION: Because the progression of concomitant or secondary appendicitis is rapid, we recommend frequent imaging modalities, prophylactic appendectomy be considered for patients who also have lung cancer and imaging findings show suspected metastasis to the appendix.

18.
Chem Pharm Bull (Tokyo) ; 68(11): 1055-1060, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33132372

RESUMO

In clinical practice, a thickening solution is frequently used to allow easy swallowing of tablets by patients suffering from dysphagia. This study investigated the effect of the thickening solution on tablet disintegration. Model tablets containing different disintegrants were prepared and their disintegration times (DTs) measured using standard methods. We also performed an additional disintegration test on the model tablets after immersing them for 1 min in thickening solution containing xanthan gum (XTG-SOL) ("modified disintegration test"). The DTs of the test tablets were substantially prolonged by immersion in XTG-SOL. Furthermore, the effect of the XTG-SOL on the DTs differed depending on the type of disintegrant contained in the tablets. To investigate in more detail this prolongation of tablet disintegration, we examined the contribution of tablet properties to their DTs. The properties analyzed included contact angle, T2 relaxation time, wetting time, and water absorption ratio. The contributions of these properties to the DTs were analyzed using multiple regression analysis. This analysis clarified that the tablet properties affecting DTs changed after immersion in XTG-SOL: wetting time significantly affected the DTs measured in the normal disintegration test, while T2 was crucial for the DTs of tablets immersed in XTG-SOL. These findings provide valuable information for design of tablet formulations, and for clinical medication management for older patients with dysphagia.

19.
Insect Sci ; 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33205542

RESUMO

Caterpillars (Lepidoptera and Symphyta larvae) employ diverse visual defensive tactics, and effectiveness of such tactics may be highly dynamic across time due to seasonal changes in the predator assemblages and their preference. This, however, has rarely been studied especially in tropical regions. Here we assessed temporal changes in the defensive value of caterpillar color and shape, using six types of plasticine dummy caterpillars: three colors (green, black, and white) × two shapes (curled and straight). These dummy caterpillars were deployed five times over different seasons in tropical forests of Xishuangbanna (China) and, as a comparison, twice in a temperate forest of Hirosaki (Japan). The colors and shapes of dummy caterpillars simulate visual traits of black sawfly larvae which take the curled resting posture in tropical rainforests of Xishuangbanna, apparently masquerading excrements commonly found on plants, while in Hirosaki there is no black-curled sawfly larvae and few excrements on plants. We found no significant effects of caterpillar colors or shapes on predation in Hirosaki. In contrast, black and curled caterpillars received significantly lower predation by birds in Xishuangbanna constantly across time. We, however, were unable to provide evidence that the black-curled sawfly larvae is masquerading as excrements. Shapes of the dummy caterpillars also affected the predation by ants and parasitoid wasps at certain times. This is the first report on ecological function of the curled posture of sawfly larvae, and we demonstrated the importance to assess the temporal dynamics of predation and effectiveness of defensive tactics in tropical forests. This article is protected by copyright. All rights reserved.

20.
Ecol Evol ; 10(12): 5852-5863, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32607195

RESUMO

A key focus of ecologists is explaining the origin and maintenance of morphological diversity and its association with ecological success. We investigate potential benefits and costs of a common and varied morphological trait, cuticular spines, for foraging behavior, interspecific competition, and predator-prey interactions in naturally co-occurring spiny ants (Hymenoptera: Formicidae: Polyrhachis) in an experimental setting. We expect that a defensive trait like spines might be associated with more conspicuous foraging, a greater number of workers sent out to forage, and potentially increased competitive ability. Alternatively, consistent with the ecological trade-off hypothesis, we expect that investment in spines for antipredator defense might be negatively correlated with these other ecological traits. We find little evidence for any costs to ecological traits, instead finding that species with longer spines either outperform or do not differ from species with shorter spines for all tested metrics, including resource discovery rate and foraging effort as well as competitive ability and antipredator defense. Spines appear to confer broad antipredator benefits and serve as a form of defense with undetectable costs to key ecological abilities like resource foraging and competitive ability, providing an explanation for both the ecological success of the study genus and the large number of evolutionary origins of this trait across all ants. This study also provides a rare quantitative empirical test of ecological effects related to a morphological trait in ants.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...