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We have investigated the birefringence in packed films of binary spherical colloidal particles. Particulate films were obtained by drying a mixed suspension of colloidal particles with two different diameters. We observed positive and negative birefringence depending on the diameters and volume ratios of the large and small particles. When the diameters of the large and small particles were similar, the films showed positive birefringence. However, negative birefringence or weakening of positive birefringence was observed in films with a large diameter ratio and an optimal volume fraction of large particles. The large particles were embedded in packed small particles in the negative and weakened positive birefringent films. We propose a packing structure in which a single shell layer of small particles formed around a large particle. Using this model, we estimated the required volume ratio of large particles, and it was in good agreement with the optimal volume fraction. The relation between the packing structure of the binary colloidal particles and the birefringence is discussed.

A clear back flow was observed in the thin unidirectional drying cell of a colloidal suspension. Flow around the colloidal-particle packing front was more complex than expected, even though a colloidal suspension was confined in a narrow space with a submillimeter-scale or shorter gap height. We propose that an increase in particle concentration around the packing front induces downward flow, which is the origin for back flow inside the cell. A mathematical model, which considered both a drying induced horizontal flow and a circulation flow caused by a concentration gradient of particles, showed a reasonable agreement with experimental data for the width of the back-flow region. The concentration gradient of particles was not negligible and it generated a rather complicated flow even in a thin drying liquid film.

Correction for ‘Drying-induced back flow of colloidal suspensions confined in thin unidirectional drying cells’ by Kai Inoue et al., RSC Adv., 2020, 10, 15763–15768, https://doi.org/10.1039/D0RA02837A.

We have synthesized a mat of silicon nanowires (approx. 10 mg in weight and 20 cm2 in size) via the zinc reduction of silicon tetrachloride. The mat consisted of smooth and long nanowires with a median diameter (d50) of 40 nm. The flow pattern of gas inside the reactor that was used to form the mat significantly affected the formation of nanowires, even though conditions such as temperature or flow rates were fixed. In the best flow pattern, nanowires preferentially formed on a fixed position in the reactor and the mat gradually thickened as the reaction time increased. Computational fluid dynamic (CFD) simulations revealed that both a slow circulation flow of gases and a reaction front formed around the best position in the reactor, which resulted in the largest yield. This suggested that the reaction gases required a longer residence time for the preferential formation of the nanowires. The mechanism of this selective nanowire formation is discussed.

Metabolic engineering of microorganisms to produce specialized plant metabolites has been established. However, these methods are limited by low productivity and the intracellular accumulation of metabolites. Here, we aimed to use transport engineering for producing reticuline, an important intermediate in the alkaloid biosynthetic pathway. We established a reticuline-producingEscherichia colistrain and introduced a multidrug and toxic compound extrusion transporter,ArabidopsisAtDTX1, into it. AtDTX1 was selected due to its suitable expression inE. coliand its reticuline-transport activity. Expression of AtDTX1 significantly enhanced reticuline production by 11-fold; produced reticuline was secreted into the medium. AtDTX1 expression conferred high plasmid stability, and up- or downregulated genes associated with biological processes including metabolic pathways for reticuline biosynthesis, leading to a high production and secretion of reticuline. The successful application of a transporter for alkaloid production suggests that the transport engineering approach may improve the biosynthesis of specialized metabolites via metabolic engineering.

Microorganisms can be metabolically engineered to produce specialized plant metabolites. However, these methods are limited by low productivity and intracellular accumulation of metabolites. We sought to use transport engineering for producing reticuline, an important intermediate in the alkaloid biosynthetic pathway. In this study, we established a reticuline-producing Escherichia coli strain into which the multidrug and toxic compound extrusion transporter Arabidopsis AtDTX1 was introduced. AtDTX1 was selected due to its suitable expression in E. coli and its reticuline-transport activity. Expression of AtDTX1 enhanced reticuline production by 11-fold, and the produced reticuline was secreted into the medium. AtDTX1 expression also conferred high plasmid stability and resulted in upregulation or downregulation of several genes associated with biological processes, including metabolic pathways for reticuline biosynthesis, leading to the production and secretion of high levels of reticuline. The successful employment of a transporter for alkaloid production suggests that the proposed transport engineering approach may improve the biosynthesis of specialized metabolites via metabolic engineering.

Lettuce big-vein disease, caused by Mirafiori lettuce big-vein virus and Lettuce big-vein associated virus, is suppressed when the pH of field soil becomes acidic. Therefore, we evaluated the effect of soil pH on the activities of Olpidium virulentus, the vector of the viruses. We found that acidic soil, pH less than 6.0, significantly reduced O. virulentus infection of the root and influenced the detection rate of zoospores released in the surrounding water. We concluded that acidic soil suppresses zoospore release from zoosporangia.

Negative thinking/affect (NTA) in depression and anxiety is an important target of clinical intervention. However, individuals recognize the benefit of NTA. There is a need to develop a scale for empirical studies of NTA. Two-hundred and fifty-nine Japanese university students were assigned to answer: (a) the state in the past week (positive affect (PA) and Center for Epidemiologic Studies Depression Scale), (b) the current state (PA and State-Trait Anxiety Inventory-State (STAI-S)), and (c) the usual state (PA and STAI-Trait), after completing the Recognized Benefit of NTA Scale (RBNTA). Another 291 students completed the Rosenberg Self-Esteem Scale and the Revised Life Orientation Test, after completing the RBNTA. Two weeks later, 76 participants completed the RBNTA. The RBNTA with nine subscales was developed after comparing the indices of fitness from 14 different factor solutions. The internal and test-retest reliability and content validity were confirmed. Correlation analyses revealed that the recognition of trying to obtain benefits/avoid costs tends to associate with positive/negative affect and that most of such recognitions did not associate with self-esteem and optimism.

To clarify phylogenetic relationships and genetic diversity among Bartonella washoensis strains obtained from squirrels, multi-locus sequence analysis (MLSA) with the 16S rRNA, ftsZ, gltA, groEL, ribC, and rpoB genes was applied for 20 strains of B. washoensis isolated from five genera of squirrels (Tamias, Tamiasciurus, Glaucomys, Sciurus, and Spermophilus) within the family Sciuridae. Sequence similarities in the concatenated sequences of B. washoensis strains from squirrels of different genera ranged from 94.7% (Sciurus vs. Spermophilus) to 98.4% (Tamiasciurus vs. Glaucomys). Phylogenetic trees based on the concatenated sequences revealed that B. washoensis strains formed five distinct clades and each clade correlated with the genus of squirrel from which the strains were originally obtained. The discrimination was supported by 100% bootstrap values and posterior probabilities, respectively. These results suggest that B. washoensis strains may have co-speciated with their squirrel hosts and provide new insights into the application of the MLSA to identify sources of B. washoensis infection with accuracy.

At least 12 species in the genus Bartonella are zoonotic pathogens that may be transmitted among mammalian hosts by fleas or other arthropods. Apparent host specificity by some Bartonella species to mammalian hosts has been observed, and the detection of multiple Bartonella species in mammalian fleas suggests that fleas take bloodmeals from a variety of host species. However, many flea species are observed to parasitize a narrow host range. Therefore, we suspect that fleas may acquire Bartonella by a mechanism other than ingesting infectious blood. We found that detection of multiple Bartonella genotypes and species is apparently common in fleas and that the majority of fleas tested (5/9) carried Bartonella species atypical of their hosts. We also detected Bartonella DNA in flea reproductive tissues, suggesting that vertical transmission of this organism in vectors is possible, potentially leading to the accumulation of Bartonella diversity over time within fleas.

To evaluate the risk for emerging human infections caused by zoonotic Bartonella spp. from exotic small mammals, we investigated the prevalence of Bartonella spp. in 546 small mammals (28 species) that had been imported into Japan as pets from Asia, North America, Europe, and the Middle and Near East. We obtained 407 Bartonella isolates and characterized them by molecular phylogenetic analysis of the citrate synthase gene, gltA. The animals examined carried 4 zoonotic Bartonella spp. that cause human endocarditis and neuroretinitis and 6 novel Bartonella spp. at a high prevalence (26.0%, 142/546). We conclude that exotic small mammals potentially serve as reservoirs of several zoonotic Bartonella spp.

Here, we describe for the first time the prevalence and genetic properties of Bartonella organisms in wild rodents in Japan. We captured 685 wild rodents throughout Japan (in 12 prefectures) and successfully isolated Bartonella organisms from 176 of the 685 rodents (isolation rate, 25.7%). Those Bartonella isolates were all obtained from the rodents captured in suburban areas (rate, 51.8%), but no organism was isolated from the animals captured in city areas. Sequence analysis of rpoB and gltA revealed that the Bartonella isolates obtained were classified into eight genetic groups, comprising isolates closely related to B. grahamii (A-I group), B. tribocorum and B. elizabethae (B-J group), B. tribocorum and B. rattimassiliensis (C-K group), B. rattimassiliensis (D-L group), B. phoceensis (F-N group), B. taylorii (G-O group), and probably two additional novel Bartonella species groups (E-M and H-P). B. grahamii , which is one of the potential causative agents of human neuroretinitis, was found to be predominant in Japanese rodents. In terms of the relationships between these Bartonella genetic groups and their rodent species, (i) the A-I, E-M, and H-P groups appear to be associated with Apodemus speciosus and Apodemus argenteus ; (ii) the C-K, D-L, and F-N groups are likely implicated in Rattus rattus ; (iii) the B-J group seems to be involved in Apodemus mice and R. rattus ; and (iv) the G-O group is probably associated with A. speciosus and Clethrionomys voles. Furthermore, dual infections with two different genetic groups of bartonellae were found in A. speciosus and R. rattus . These findings suggest that the rodent in Japan might serve as a reservoir of zoonotic Bartonella infection.

We collected 641 small mammals belonging to 17 species of Rodentia and four species of Soricomorpha in Japan, Korea, Russia, Taiwan, and Thailand and investigated the prevalence and genetic diversity of Bartonella species. Apodemus (field mice) and Rattus (rats) were the most-common genera captured, making up 56.0% and 23.1% of the total specimens, respectively. Bartonellae were isolated from 54.6% of the collected animals, and the prevalence varied depending on the host species and the country of origin. The isolates were identified to the species level based on gltA and rpoB sequences. Although most Bartonella species were shared by more than two host species, the distribution patterns of Bartonella species clearly differed among the four most-common host genera: Apodemus, Rattus, Myodes (voles), and Suncus (shrews). The predominant Bartonella species were Bartonella grahamii in Apodemus, Bartonella tribocorum in Rattus, B. grahamii and Bartonella taylorii in Myodes, and an unclassified Bartonella sp. in Suncus.

Yersinia enterocolitica was isolated from 15.7% (88/560) of wild rodents captured in 15 prefectures in Japan. Prevalences by rodent species were 18.0% (70/388) in Japanese field mice (Apodemus speciosus), 20% (14/71) in small Japanese field mice (Apodemus argenteus), and 11% (4/38) in gray red-backed vole (Myodes rufocanus bedfordiae), suggesting that these rodent species are important reservoirs of Y. enterocolitica. Although most of the isolates were identified as biotype 1A, the pathogenic bioserotype 1B/O:8 was detected in one of the A. speciosus and in three of the A. argenteus captured in Aomori Prefecture. It is suggested that Apodemus mice may be an important reservoir of Y. enterocolitica, and that there are foci of the pathogenic bioserotype 1B/O:8 in Aomori Prefecture, because human sporadic cases by the serotype have been reported in this prefecture.

Four novel strains of members of the genus Bartonella , OY2-1T, BR11-1T, FN15-2T and KS2-1T, were isolated from the blood of wild-captured greater Egyptian jerboa (Jaculus orientalis), plantain squirrel (Callosciurus notatus), fat-tailed gerbil (Pachyuromys duprasi) and golden spiny mouse (Acomys russatus). All the animals were imported to Japan as pets from Egypt, Thailand and the Netherlands. The phenotypic characterization (growth conditions, incubation periods, biochemical properties and cell morphologies), DNA G+C contents (37.4 mol% for strain OY2-1T, 35.5 mol% for strain BR11-1T, 35.7 mol% for strain FN15-2T and 37.2 mol% for strain KS2-1T), and sequence analyses of the 16S rRNA genes indicated that those strains belong to the genus Bartonella . Sequence comparisons of gltA and rpoB genes suggested that all of the strains should be classified as novel species of the genus Bartonella . In phylogenetic trees based on the concatenated sequences of five loci, including the 16S rRNA, ftsZ, gltA and rpoB genes and the ITS region, and on the concatenated deduced amino acid sequences of three housekeeping genes (ftsZ, gltA and rpoB), all strains formed distinct clades and had unique mammalian hosts that could be discriminated from other known species of the genus Bartonella . These data strongly support the hypothesis that strains OY2-1T, BR11-1T, FN15-2T and KS2-1T should be classified as representing novel species of the genus Bartonella . The names Bartonella jaculi sp. nov., Bartonella callosciuri sp. nov., Bartonella pachyuromydis sp. nov. and Bartonella acomydis sp. nov. are proposed for these novel species. Type strains of Bartonella jaculi sp. nov., Bartonella callosciuri sp. nov., Bartonella pachyuromydis sp. nov. and Bartonella acomydis sp. nov. are OY2-1T ( = JCM 17712T = KCTC 23655T), BR11-1T ( = JCM 17709T = KCTC 23909T), FN15-2T ( = JCM 17714T = KCTC 23657T) and KS2-1T ( = JCM 17706T = KCTC 23907T), respectively.

The purpose of this study was to assess the role of fleas for transmission of Bartonella species among wild rodents in Japan. Flea samples were collected from wild rodents and examined genetically for Bartonella infection. Bartonella DNA was detected from 16 of 40 (40.0%) flea samples. Sequence analysis demonstrated that 3 of 16 (18.8%) of the Bartonella-positive animals were infested with fleas from which the closely related Bartonella DNA sequence was detected, indicating that the fleas acquired Bartonella from the infested rodents. The DNA was detected in hemolymph, the midgut and the ovary (only in female), indicating that Bartonella might be colonized through the midgut and distributed into the body.

We investigated the seroprevalence of five tick- or mite-borne zoonoses, scrub typhus (Orientia tsutsugamushi), Japanese spotted fever (Rickettsia japonica), tularemia (Francisella tularensis), Lyme disease (Borrelia afzelii and Borrelia garinii), and Q fever (Coxiella burnetii), in feral raccoons (Procyon lotor) captured in Hokkaido and Kanagawa Prefectures in Japan. Of the 559 raccoons captured in Hokkaido, 8 (1.4%), 3 (0.5%), 1 (0.2%), and 1 (0.2%) carried antibodies against O. tsutsugamushi (Gilliam type), F. tularensis, B. afzelii, and B. garinii, respectively. Of the 193 animals investigated in Kanagawa, 31 (16.1%) and 14 (7.3%) carried antibodies against O. tsutsugamushi and R. japonica, respectively, and the major serotype (27/31) of O. tsutsugamushi was Kuroki. No antibodies against C. burnetii were detected in either area examined. Therefore, feral raccoons could be an indicator of the prevalence of these four tick- or mite-borne zoonoses in the peridomestic environment in Japan.

Two bacterial strains, Fuji 18-1Tand Fuji 23-1T, were isolated from the blood of the small Japanese field mouse (Apodemus argenteus) and the large Japanese field mouse (Apodemus speciosus), respectively, specimens of which were captured in the forest of Mount Fuji, Japan. Phenotypic characterization (growth conditions, incubation periods, biochemical properties and cell morphologies), DNA G+C contents (40.1 mol% for strain Fuji 18-1Tand 40.4 mol% for strain Fuji 23-1T) and sequence analyses of the 16S rRNA genes indicated that both strains were members of the genusBartonella. UsingrpoBandgltAsequencing analysis, the highest sequence similarities between strains Fuji 18-1T, Fuji 23-1Tand other recognized species of the genusBartonellashowed values considerably lower than 91.4 % and 89.9 % in therpoBgene and 89.1 % and 90.4 % in thegltAgene, respectively. It is known that similarities of 95.4 % for therpoBgene and 96.0 % for thegltAgene can be applied as cut-off values for the designation of novel species of the genusBartonella. In a phylogenetic tree based on the merged set of concatenated sequences of seven loci [16S rRNA,ftsZ,gltA,groEL,ribCandrpoBgenes and the intergenic spacer region (ITS)], strains Fuji 18-1Tand Fuji 23-1Tformed a distinct clade from other recognized species of the genusBartonella. These data support the classification of strains Fuji 18-1Tand Fuji 23-1Tas novel species of the genusBartonella. The namesBartonella japonicasp. nov. andBartonella silvaticasp. nov. are proposed for these novel species. The type strains ofBartonella japonicasp. nov. andBartonella silvaticasp. nov. are Fuji 18-1T(=JCM 15567T=CIP 109861T) and Fuji 23-1T(=JCM 15566T=CIP 109862T), respectively.

To clarify the relationship between Bartonella grahamii strains and both the rodent host species and the geographic location of the rodent habitat, we have investigated 31 B. grahamii strains from ten rodent host species from Asia (Japan and China), North America (Canada and the USA), and Europe (Russia and the UK). On the basis of multi-locus sequencing analysis of 16S rRNA, ftsZ, gltA, groEL, ribC, and rpoB, the strains were classified into two large groups, an Asian group and an American/European group. In addition, the strains examined were clearly clustered according to the geographic locations where the rodents had been captured. In the phylogenetic analysis based on gltA, the Japanese strains were divided into two subgroups: one close to strains from China, and the other related to strains from Far Eastern Russia. Thus, these observations suggest that the B. grahamii strains distributed in Japanese rodents originated from two different geographic regions. In the American/European group, B. grahamii from the North American continent showed an ancestral lineage and strict host specificity; by contrast, European strains showed low host specificity. The phylogenetic analysis and host specificity of B. grahamii raise the possibility that B. grahamii strains originating in the North American continent were distributed to European countries by adapting to various rodent hosts.