Last-minute travelers were defined as those travelers who planned

Last-minute travelers were defined as those travelers who planned their trip within 2 weeks from departure. Respondents who specifically stated that their main purpose for travel was to visit friends and relatives were considered VFRs. Knowledge of hepatitis A was determined by comparison of the risk for hepatitis A as perceived by the traveler with the actual

risk for hepatitis A, as described.8 To that end, all destinations (including those in malaria-endemic countries) were Erlotinib mw rated as low-, intermediate-, or high-risk destination for hepatitis A based on maps published by the Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.9

The accuracy (correct risk perception) was expressed as a percentage of maximal correctness, ranging from 0 to 100%. To determine U0126 the attitude (intended risk behavior) of participants toward hepatitis A, all participants were asked if they were planning to consume possibly contaminated food items such as tap water, ice cubes, raw shellfish, ice-cream, and salads. Each affirmative answer was scored with one point, whereas a negation was scored with 0 points. The final attitude score could range from 0 to 5; for convenience, the score was transformed to a 0 to 100% scale with the maximal risk score set at 100%. To have an indication of their practice (protection rate), travelers were considered to be protected against hepatitis A if they were either vaccinated for this trip, or fully vaccinated in the past (at least two doses of hepatitis A vaccine, or three doses of combined hepatitis A and B vaccine), or naturally immune;

others were considered to be unprotected. Buspirone HCl Protection rate was expressed as a percentage of protected individuals and could range from 0 to 100%. To estimate the impact of KAP of the travel risk group of interest on relative risk for hepatitis A, a composite estimate was constructed by summing up the effects of the separate determinants. To that end, it was assumed that either a poor risk perception, intended risk-seeking behavior, or poor protection rates led to an equal increase in relative risk for hepatitis A. Several statistical analyses were made between travelers to high- and to low-to-intermediate-risk destinations: on one hand the so-called “between risk destinations” analysis: eg, the comparison of VFRs traveling to high-risk destinations versus VFRs traveling to low-to-intermediate-risk destinations) and on the other hand the so-called “within risk destination” analyses: eg, the comparison of solo travelers to high-risk destinations versus the remaining (non-solo) travelers to high-risk destinations.

Among them, 1-decanol (C10) showed highest activity against both

Among them, 1-decanol (C10) showed highest activity against both M. smegmatis and M. tuberculosis. In addition, the current study also shows that the presence of a terminal double bond in a fatty alcohol potentiates its antimycobacterial activity. This antimycobacterial activity of the alcohols was found to be partly, if not exclusively, due to damage to the cellular envelope. The ability of 1-decanol and 9-decene-1-ol to attenuate biofilm formation by M. smegmatis was also investigated. All the alkanes, alkanols and alkene-1-ol used in this study were purchased from Sigma-Aldrich (St Louis, MO). Mycobacterium smegmatis mc2155 (ATCC 700084) and M. tuberculosis H37Rv (ATCC 25618) used in Dabrafenib cell line this study were a kind gift from Prof.

Sujoy Dasgupta, Bose Institute, Kolkata,

India, and Prof. N. K. Pal, IPGMER, Kolkata, India. Middlebrook 7H9 broth base supplemented with glycerol and bovine serum albumin was used for cultivation of M. smegmatis and Kirchner’s broth supplemented with antibiotic cocktail Polymyxin B, Amphotericin B, Carbenicillin, Trimethoprim was used for cultivation of M. tuberculosis. The medium contains phenol red as a pH indicator that turns yellow from pink upon growth of the M. tuberculosis. Preliminary assessment for antimycobacterial activity of long-chain fatty alcohols was done by agar diffusion method as described previously (Bauer et al., 1966). Briefly, paper discs of 4 mm in diameter soaked MAPK Inhibitor Library high throughput with 3 μL of each alcohol were placed on agar plates overlaid with soft agar (0.6%) that was inoculated with M. smegmatis mc2155. Plates were incubated for 48 h at 37 °C. The extent of inhibition was measured by the diameter of the zone of inhibition created around the

disc. The BDS method was performed as described previously (Charles, 1974). Briefly the compound to be tested was dissolved at a concentration of 8 mg mL−1 in 70% dimethyl sulfoxide and was further diluted twofold in each consecutive test tube in either Middlebrook 7H9 broth (Difco, Detroit, MI) for M. smegmatis mc2155 or in Kirchner’s broth for M. tuberculosis H37Rv. An aliquot (10 μL) of an CHIR-99021 mw overnight culture of either M. smegmatis mc2 155 or M. tuberculosis H37Rv (ca. 1 × 105 CFU mL−1) were added to each tube. Each culture was incubated at 37 °C for 48 h. The minimum inhibitory concentration (MIC) was defined as the lowest concentration at which there was no visible growth of the bacteria after 48 h of incubation. Mycobacterium tuberculosis growth in Kirchner’s medium is indicated by the change in colour from pink to yellow due to pH change of the medium by acid produced during growth of M. tuberculosis. The minimum concentration of agent at which no colour change of the growth medium was observed was designated as the MIC. Mycobacterium smegmatis mc2155 cells were grown to log phase and either treated with 0.8 mM of decanol for 2 h or left untreated. Cells were smeared on a glass cover slip, dried in air for 30 min and examined under AFM (Veeco, Singapore).

4%) were subtype B, with a higher rate in the MSM group (n = 183;

4%) were subtype B, with a higher rate in the MSM group (n = 183; 93.8%) (Table 1). DRMs were found in a total of 38 patients among the 266 sequences tested (14.3%). There was a constant increase in mutation rate PF-562271 mw (P = 0.001 for trend): while there

were no resistance mutations between 2001 and 2005 (n = 35), there were 14.3% in 2006 (n = 14), 9.5% in 2007 (n = 42), 11.4% in 2008 (n = 61) and 21.9% in 2009 (n = 114). Resistance mutations were exclusively from the MSM ERC. Excluding two subtype A viruses, all DRMs were subtype B viruses. Within the mutated viruses, 18 (6.8%) harboured nonnucleoside reverse transcriptase inhibitor (NNRTI)-associated resistance mutations, with K103N being the most abundant; 15 (5.6%) had protease inhibitor (PI)-associated mutations; and three (1.1%) had nucleoside reverse transcriptase inhibitor (NRTI)-associated mutations. One virus had

two classes (NNRTI and PI) and another virus harboured three classes of associated resistance mutations. Although not statistically significant (P = 0.66), in 2009 we documented a switch in the abundance of mutations as PI DRMs became more frequent than NNRTI DRMs (11.4% vs. 8.7%, respectively). Phylogenetic analysis carried out on a total of 198 subtype B sequences identified two major clusters of DRMs (Fig. 1a). One of the identified clusters included 13 of the 14 viruses harbouring the L90M major Doramapimod molecular weight PI-resistance mutation grouped together with a bootstrap support of 100%. Eleven patients within this cluster were diagnosed in 2009, one in 2008 and one in 2006.

The low evolutionary distance between these sequences and their pattern of segregation suggest a single source of infection Etoposide solubility dmso (Fig. 1b). The second cluster included 12 of 17 viruses harbouring the K103N NNRTI-associated resistance mutation (Fig. 1c). We further looked into the laboratory characteristics and response to cART of patients infected with the L90M viruses. A large range of viral loads and CD4 counts were found at baseline (989–100 000 HIV-1 RNA copies/ml and 150–760 cells/μl, respectively). Seven of the clustered L90M-infected patients started cART. One of the three patients who were treated with efavirenz and tenofovir/emtricitabine failed to suppress the viral load and rapidly developed the K103N resistance mutation in RT despite good adherence. In contrast, two others responded well to the same regimen. Four patients were given a higher genetic barrier regimen, for example darunavir. Three of them maintained their viral load below 40 copies/ml, but one failed to suppress the viral load below 40 copies/ml. Similar to previous reports from other industrialized countries and Israel [4, 13-16], the data presented herein demonstrate an increasing rate of DRMs in the treatment-naïve population in Tel Aviv, mainly in the MSM ERC.

4%) were subtype B, with a higher rate in the MSM group (n = 183;

4%) were subtype B, with a higher rate in the MSM group (n = 183; 93.8%) (Table 1). DRMs were found in a total of 38 patients among the 266 sequences tested (14.3%). There was a constant increase in mutation rate Selleck Ivacaftor (P = 0.001 for trend): while there

were no resistance mutations between 2001 and 2005 (n = 35), there were 14.3% in 2006 (n = 14), 9.5% in 2007 (n = 42), 11.4% in 2008 (n = 61) and 21.9% in 2009 (n = 114). Resistance mutations were exclusively from the MSM ERC. Excluding two subtype A viruses, all DRMs were subtype B viruses. Within the mutated viruses, 18 (6.8%) harboured nonnucleoside reverse transcriptase inhibitor (NNRTI)-associated resistance mutations, with K103N being the most abundant; 15 (5.6%) had protease inhibitor (PI)-associated mutations; and three (1.1%) had nucleoside reverse transcriptase inhibitor (NRTI)-associated mutations. One virus had

two classes (NNRTI and PI) and another virus harboured three classes of associated resistance mutations. Although not statistically significant (P = 0.66), in 2009 we documented a switch in the abundance of mutations as PI DRMs became more frequent than NNRTI DRMs (11.4% vs. 8.7%, respectively). Phylogenetic analysis carried out on a total of 198 subtype B sequences identified two major clusters of DRMs (Fig. 1a). One of the identified clusters included 13 of the 14 viruses harbouring the L90M major Alectinib PI-resistance mutation grouped together with a bootstrap support of 100%. Eleven patients within this cluster were diagnosed in 2009, one in 2008 and one in 2006.

The low evolutionary distance between these sequences and their pattern of segregation suggest a single source of infection RVX-208 (Fig. 1b). The second cluster included 12 of 17 viruses harbouring the K103N NNRTI-associated resistance mutation (Fig. 1c). We further looked into the laboratory characteristics and response to cART of patients infected with the L90M viruses. A large range of viral loads and CD4 counts were found at baseline (989–100 000 HIV-1 RNA copies/ml and 150–760 cells/μl, respectively). Seven of the clustered L90M-infected patients started cART. One of the three patients who were treated with efavirenz and tenofovir/emtricitabine failed to suppress the viral load and rapidly developed the K103N resistance mutation in RT despite good adherence. In contrast, two others responded well to the same regimen. Four patients were given a higher genetic barrier regimen, for example darunavir. Three of them maintained their viral load below 40 copies/ml, but one failed to suppress the viral load below 40 copies/ml. Similar to previous reports from other industrialized countries and Israel [4, 13-16], the data presented herein demonstrate an increasing rate of DRMs in the treatment-naïve population in Tel Aviv, mainly in the MSM ERC.

1–69 mmol/L), an OGTT may be considered as it may reveal DM How

1–6.9 mmol/L), an OGTT may be considered as it may reveal DM. However, an OGTT with normal FPG values may reveal IGT or DM; furthermore, an early diagnosis of IGT could allow the introduction of measures, such as changes in lifestyle or in antiretroviral Sotrastaurin treatment, aimed at preventing progression to full-blown DM, and in turn an early diagnosis of DM could help to avoid the severe complications of the disease

[31,32]. Screening for pre-diabetes and type 2 DM in asymptomatic people should be considered in adults of any age who are overweight or obese (BMI≥25 kg/m2) and have one or more additional risk factors for diabetes [25]. HIV-infected patients have additional risks associated with drug treatment [2–10] that make them click here candidates for proactive screening. The OGTT revealed that 11% of our cohort of (predominantly male) Caucasian patients with long-standing HIV infection had IGT or DM, undiagnosed on the basis of

FPG levels; among the considered factors, only CD4 cell counts and HOMA-IR predicted abnormal glucose tolerance. No previous study has the same design as ours, and so our results cannot be directly compared with others. Type 2 DM is frequently not diagnosed until complications appear, and approximately one-third of all people with diabetes may be undiagnosed. Although the effectiveness of identifying pre-diabetes and diabetes early by means of the mass testing of asymptomatic individuals has not been conclusively demonstrated (and rigorous trials to provide such a conclusive demonstration are unlikely to be carried out), pre-diabetes and diabetes meet the established criteria new for conditions for which early detection is appropriate [25]. The presence of pre-diabetes or diabetes can be established on the basis of FPG levels or a 2-h OGTT (75-g glucose load) or both. The OGTT is more sensitive and slightly more specific for diagnosing diabetes, but FPG is currently recommended because

the OGTT is more difficult to perform in practice and the results are less reproducible; however, the OGTT may be useful for further evaluating patients in whom diabetes is still strongly suspected but who have normal or impaired FPG levels [25]. In HIV-infected patients, FPG levels may be relatively insensitive for detecting all cases of DM: one study found that 72% of men meeting the criteria for DM by the 75-g OGTT had nondiabetic FPG levels, which is why the OGTT is considered necessary in studies aiming to capture all cases of DM in this patient population [33]. The duration of glycaemia is a strong predictor of adverse outcomes, and there are effective means of preventing the progression of pre-diabetes to DM and reducing the risk of disease complications [25]. This may be particularly important in HIV-infected patients, who are at higher risk of cardiovascular diseases than the general population [16,17].

Consistent with ITS and β-tubulin phylogenies, molecular clusteri

Consistent with ITS and β-tubulin phylogenies, molecular clustering based on lac3-1 sequence analysis grouped the P. cinnabarinus and P. puniceus strains into two highly supported specific lineages. The P. sanguineus and P. coccineus strains were distributed through four distinct, well supported clades

and sub-clades. A neotropical sub-clade grouped the P. sanguineus strains from French Guiana and Venezuela – and the reference strain CIRM-BRFM 902 – corresponding to P. sanguineus sensu stricto. A paleotropical sub-clade clustered the strains from Madagascar, Vietnam and New Caledonia, and could be defined as Pycnoporus cf. sanguineus. The Australian clade of P. coccineus, including the reference strain MUCL 39523, corresponded to P. coccineus sensu stricto. This clade also included

MAPK inhibitor the Malesian strain from the Solomon Islands, positioned separately, consistent with the high level of endemic species in that country (Udvardy, 1975). Target Selective Inhibitor Library ic50 The fourth group was the Eastern Asian region clade, clustering the strains from China, including CIRM-BRFM 542 of unknown origin and the strain MUCL 38527 from Japan. The strains of this last clade shared polymorphism in ITS and β-tubulin sequences with P. coccineus sensu stricto strains, as well as intron length in β-tubulin gene sequences, known to be characteristic of a lineage in basidiomycetes (Begerow et al., 2004). This suggests a misidentification of Chinese specimens, very recently confirmed by macroscopic observation of basidiocarps. The high degree of similarity of the morphological characters between Etomidate P. sanguineus and P. coccineus and the high variability of specimens across the season and the geographical area could explain this field misidentification (Nobles & Frew, 1962). Accordingly, the

Eastern Asian region strains of Pycnoporus (from China and Japan), together with the related strain CIRM-BRFM 542 (suspected to be of East Asian descent), formed a P. coccineus-like group defined as Pycnoporus cf. coccineus (Fig. 3). Biogeographic phylogenetic structure was related in polyporoid fungi such as Grifola frondosa, separating Eastern North American strains from Asian strains, and no morphological distinction was detected between them (Shen et al., 2002). In the Ganoderma applanatum/australe species complex, eight distinct clades were strongly correlated with the geographic origin of the strains, and corresponded to mating groups (Moncalvo & Buchanan, 2008). Interestingly, the East Asian clade in our study corresponded to the functional group of Pycnoporus strains previously reported for their high level of laccase production (Lomascolo et al., 2002).

As reported, the pair of primers (799f and 1492r) would not ampli

As reported, the pair of primers (799f and 1492r) would not amplify chloroplast 16S rRNA

from 41 plants and mitochondrial 18S rRNA of six Chlorophyta plants. In this study, we obtained only one band approximately 700 bp of bacterial 16S rRNA fragments using this pair of primers. This demonstrated that the primers 799f and 1492r could specifically amplify the endophytic bacterial click here 16S rRNA fragments and could not amplify mitochondrial 18S rRNA in reed roots; thus, it was suitable for use in the study of reed root endophytic bacteria. Proteobacteria were the most dominant group in our clone library and all five classes were detected, which was consistent with other studies (Chelius & Triplett, 2001; Sun et al., 2008). In the most abundant subgroup of Alphaproteobacteria, 10 clones were assigned to Pleomorphomonas oryzae and Pleomorphomonas koreensis, both nitrogen-fixing bacteria (Xie & Yokota, 2005; Im et al., 2006); nine clones were related selleck chemicals llc to A. picis, which was also identified as a nitrogen fixer (Peng et al., 2006). Other Azospirillum species have been isolated from roots of numerous wild and cultivated grasses, cereals,

food crops, and soils, and proved to be capable of enhancing the growth of plants through the production of phytohormones (Bashan & Holguin, 1997) and supplying nitrogen to their host plants (Dobereiner, 1980; Okon, 1985). Another dominant subgroup was observed in the Gammaproteobacteria. A majority of the clones were highly similar to Aeromonas bivalvium 868E, which was originally isolated from bivalve mollusks (Minana-Galbis et al., 2007) and was a primary Thalidomide or an opportunistic pathogen in invertebrates and vertebrates including humans (Martin-Carnahan & Joseph, 2005). It was also demonstrated to be capable of reducing nitrate (NO3−) to nitrite (NO2−) and producing indole from tryptophan (Minana-Galbis et al., 2007). A number of sequences were very similar to bacteria in genera Beggiatoa, Pseudomonas, Enterobacter, and Dickeya. According

to previous reports, species in Beggiatoa can use NO3− anaerobically as an alternative electron acceptor in place of O2 and can perform anaerobic H2S oxidation with NO3− (Kamp et al., 2006). Thus, they have a significant impact on the aquatic nitrogen and sulfur cycles. Pseudomonads are also often found in contaminated aquifers, because they are able to use a large number of substances as energy or carbon sources and can often tolerate toxic compounds (Moore et al., 2006). Some strains of Enterobacter are reported to have the ability to fix nitrogen or display antagonistic activity to phytopathogens (Hallmann et al., 1997; Tsuda et al., 2001); they have also been shown to use phytate and play an important role in phosphorus cycling (Fuentes et al., 2009).

As reported, the pair of primers (799f and 1492r) would not ampli

As reported, the pair of primers (799f and 1492r) would not amplify chloroplast 16S rRNA

from 41 plants and mitochondrial 18S rRNA of six Chlorophyta plants. In this study, we obtained only one band approximately 700 bp of bacterial 16S rRNA fragments using this pair of primers. This demonstrated that the primers 799f and 1492r could specifically amplify the endophytic bacterial Roxadustat clinical trial 16S rRNA fragments and could not amplify mitochondrial 18S rRNA in reed roots; thus, it was suitable for use in the study of reed root endophytic bacteria. Proteobacteria were the most dominant group in our clone library and all five classes were detected, which was consistent with other studies (Chelius & Triplett, 2001; Sun et al., 2008). In the most abundant subgroup of Alphaproteobacteria, 10 clones were assigned to Pleomorphomonas oryzae and Pleomorphomonas koreensis, both nitrogen-fixing bacteria (Xie & Yokota, 2005; Im et al., 2006); nine clones were related find more to A. picis, which was also identified as a nitrogen fixer (Peng et al., 2006). Other Azospirillum species have been isolated from roots of numerous wild and cultivated grasses, cereals,

food crops, and soils, and proved to be capable of enhancing the growth of plants through the production of phytohormones (Bashan & Holguin, 1997) and supplying nitrogen to their host plants (Dobereiner, 1980; Okon, 1985). Another dominant subgroup was observed in the Gammaproteobacteria. A majority of the clones were highly similar to Aeromonas bivalvium 868E, which was originally isolated from bivalve mollusks (Minana-Galbis et al., 2007) and was a primary Cyclin-dependent kinase 3 or an opportunistic pathogen in invertebrates and vertebrates including humans (Martin-Carnahan & Joseph, 2005). It was also demonstrated to be capable of reducing nitrate (NO3−) to nitrite (NO2−) and producing indole from tryptophan (Minana-Galbis et al., 2007). A number of sequences were very similar to bacteria in genera Beggiatoa, Pseudomonas, Enterobacter, and Dickeya. According

to previous reports, species in Beggiatoa can use NO3− anaerobically as an alternative electron acceptor in place of O2 and can perform anaerobic H2S oxidation with NO3− (Kamp et al., 2006). Thus, they have a significant impact on the aquatic nitrogen and sulfur cycles. Pseudomonads are also often found in contaminated aquifers, because they are able to use a large number of substances as energy or carbon sources and can often tolerate toxic compounds (Moore et al., 2006). Some strains of Enterobacter are reported to have the ability to fix nitrogen or display antagonistic activity to phytopathogens (Hallmann et al., 1997; Tsuda et al., 2001); they have also been shown to use phytate and play an important role in phosphorus cycling (Fuentes et al., 2009).


“We present a case of Loa loa infection in a patient, 21 y


“We present a case of Loa loa infection in a patient, 21 years after visiting an endemic area for only 4 days. To our knowledge, this case represents the longest time for the diagnosis of loiasis H 89 manufacturer to be made post-exposure in a traveler and emphasizes that even short exposures can place travelers at risk. A 60-year-old man was referred to one of the authors (M. B.) after his dermatologist

(J. K. G.) extracted a filamentous round worm from a right upper eyelid swelling (Figure 1). The patient had been experiencing migratory facial edema for the past 2 years. He had visited various physicians during that time period to evaluate transient swellings on the side of his nose, left eyebrow, and right cheek. INK 128 clinical trial Workup included a CT scan of the orbits, and an MRI brain—both of which were unrevealing except for a right lacrimal gland swelling on the MRI reported as “suspicious for lymphoma.” Three biopsies were performed prior to consultation, and no evidence of lymphoma or granulomatous disease was identified. The patient was told that these swellings could be a reaction to the facial surgery he had prior to becoming symptomatic. The medical history was significant for hypertension, Gleason 6 prostate cancer, and a rhytidectomy (face lift) 10 years ago. Medications included an aspirin (81 mg) and olmesartan–hydrochlorothiazide.

Social history was negative for alcohol abuse or tobacco. Although the patient had an extensive travel history throughout Europe, Asia, and South America,

the case is notable in that he had only visited sub-Saharan Africa once: In 1989, he traveled to Lagos, Nigeria for a 3-day business trip. He did not recall any unusual bites at that time and was in an urban setting at all times during the travel. The physical examination was unremarkable for further tissue swellings. In addition, there were no stigmata of chronic lymphedema or organomegaly. The rest of the examination was normal. The white blood cell count was 7,200 cells/microliter with Fossariinae 210 absolute eosinophils. Testing for peripheral blood microfilariae was negative. The IgE level was within the normal reference range, and the urinalysis was unremarkable. Serologies were not performed since we were able to send the worm for a definitive PCR diagnosis. Chest X-ray revealed pleural plaques and rounded multifocal opacities that were deemed on PET scan to be the sequelae of prior asbestos exposure. Review of formalin-fixed, paraffin-embedded tissue sections from multiple biopsies from the patient’s neck, right inner cheek, forehead, and right eyelid between March 2009 and May 2010 demonstrated patchy lymphocytic infiltrates, sometimes extending into the subcutaneous fat with occasional multinucleated giant cells and areas of necrosis. No prominent eosinophilic infiltrates were seen on any of the biopsies. A white roundworm measuring approximately 6.5 cm in length and 0.

, 2000; Naim et al, 2001) Mature forms of TDH and TRH consist o

, 2000; Naim et al., 2001). Mature forms of TDH and TRH consist of 165 amino acids with a pair of intramolecular disulfide bonds between cysteine moieties in positions 151 and 161 (Iida & Honda, 1997). TDH-positive V. parahaemolyticus is hemolytic on Wagatsuma agar, which is a special type of blood agar; this effect is known as the Kanagawa phenomenon (Miwatani et al., 1972; Okuda & Nishibuchi, 1998). Electron microscopic observations indicated that TDH formed pore-like structures on the surface of erythrocyte membranes (Honda et al., 1992). Furthermore, when lipid bilayers were treated with TDH, single channel pore formation was observed (Hardy et al., 2004). In addition, Miwatani reported

that heating crude TDH at 60 °C inactivated its hemolytic activity but the activity was restored by rapid cooling from the denatured state at 90 °C (Miwatani

et al., 1972). This paradoxical phenomenon Forskolin is known as PI3K Inhibitor Library the Arrhenius effect, which was originally reported with the α-hemolysin of Staphylococcus aureus by S.A. Arrhenius in 1907 (Arrhenius, 1907). We have previously determined that the underlying molecular mechanism mediating the Arrhenius effect in TDH is the reversibility of amyloid fibril formation upon heating of TDH (Fukui et al., 2005). On the other hand, TRH lost its hemolytic activity upon heating at 90 °C, suggesting that TRH activity is not associated with the Arrhenius effect in the same way as TDH (Honda et al., 1988). We have also previously identified the C4-symmetric tetrameric structure of TDH and its model in low solutions using

small-angle X-ray scattering, ultracentrifugation, and transmission electron microscopy (Hamada et al., 2007), and presented the crystal structure of TDH tetramers with a central pore at a 1.5 Å resolution (Yanagihara et al., 2010). Single amino acid substitutions of TDH showed that π-cation interactions between R46 and Y140 played an important role in maintaining the tetrameric structure, whereas the monomeric mutant, R46E, lost its hemolytic activity (Yanagihara et al., 2010). TRH shares antigenicity in part with TDH. Hybridization tests with trh gene-specific DNA ligase probes showed that trh gene had nucleotide sequence variations, trh1 and trh2 gene, in clinical strains (Nishibuchi et al., 1989; Kishishita et al., 1992). The trh1 gene is 84% homologous to the trh2 gene, and its nucleotide sequence analysis indicated that it shares 68% homology with tdh gene. The amino acid sequence of trh1 gene also shares 63% homology with that of tdh gene (Nishibuchi et al., 1989). However, detailed structural analysis and the association state of native TRH remain unclear. Protein aggregation and amyloid formation are related to many protein conformational diseases, including Alzheimer’s, Huntington’s, and Parkinson’s disease (Bucciantini et al., 2002; Quist et al., 2005).