Recurrent protein-losing enteropathy complicated by postural right subclavian vein compression and right-sided thoracic duct.

We report the case of a 16-year-old female patient with protein-losing enteropathy that was suspected to be caused by thoracic duct congestion associated with postural compression of right subclavian vein. Non-contrast magnetic resonance lymphangiography showed that the thoracic duct connected to the right-sided venous angle of the right subclavian vein which was obstructed when her right arm was lifted. In this case, comprehensive screening of the lymphatics using non-contrast magnetic resonance lymphangiography, which is a minimally invasive tool with high spatial resolution, was helpful for the recognition of the specific pathophysiology. Learning objective: Lymphatic disorders associated with congenital heart disease can be fatal. The morphology and dysfunction of the lymphatic system are complicated, and when added to the complex hemodynamics inherent to congenital heart disease, the pathophysiology is more difficult to understand. To understand the complexity of the lymphatic disease, it is necessary to learn a systematic diagnostic process of lymphatic disorders. In the present case, it is beneficial to know the usefulness of non-contrast magnetic resonance lymphangiography to screen overall lymphatics.

Redundant function of the Arabidopsis phosphatidylinositol 4-phosphate 5-kinase genes PIP5K4-6 is essential for pollen germination.

Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) is a key enzyme producing the signaling lipid phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] in eukaryotes. Although PIP5K genes are reported to be involved in pollen tube germination and growth, the essential roles of PIP5K in these processes remain unclear. Here, we performed a comprehensive genetic analysis of the Arabidopsis thaliana PIP5K4, PIP5K5, and PIP5K6 genes and revealed that their redundant function is essential for pollen germination. Pollen with the pip5k4pip5k5pip5k6 triple mutation was sterile, while pollen germination efficiency and pollen tube growth were reduced in the pip5k6 single mutant and further reduced in the pip5k4pip5k6 and pip5k5pip5k6 double mutants. YFP-fusion proteins, PIP5K4-YFP, PIP5K5-YFP, and PIP5K6-YFP, which could rescue the sterility of the triple mutant pollen, preferentially localized to the tricolpate aperture area and the future germination site on the plasma membrane prior to germination. Triple mutant pollen grains under the germination condition, in which spatiotemporal localization of the PtdIns(4,5)P2 fluorescent marker protein 2xmCHERRY-2xPHPLC as seen in the wild type was abolished, exhibited swelling and rupture of the pollen wall, but neither the conspicuous protruding site nor site-specific deposition of cell wall materials for germination. These data indicate that PIP5K4-6 and their product PtdIns(4,5)P2 are essential for pollen germination, possibly through the establishment of the germination polarity in a pollen grain.

A Retrospective Study on the Effectiveness and Safety of Vancomycin versus Daptomycin in Hemodialysis Patients.

Vancomycin or daptomycin is administered to hemodialysis patients infected with methicillin-resistant Staphylococcus and Enterococcus species. Although serious concerns regarding nephrotoxicity due to vancomycin have been raised, it might not be a critical issue in hemodialysis patients. Moreover, very few studies have investigated the effectiveness of vancomycin versus daptomycin in patients undergoing hemodialysis. Hence, we retrospectively evaluated the effectiveness and safety of vancomycin and daptomycin in patients undergoing hemodialysis. We investigated the following measures: mortality, clinical and microbiological effectiveness, and incidence of adverse events in hemodialysis patients who received vancomycin or daptomycin from 2014 to 2019. Moreover, we evaluated the covariates related to 30-day mortality. We found that 73 patients received vancomycin, while 34 received daptomycin for the treatment of infections due to methicillin-resistant Staphylococcus aureus, methicillin-resistant coagulase-negative Staphylococci, and Enterococcus faecium. Mortality after vancomycin treatment was significantly lower than daptomycin treatment (4.1% vs. 26.5%, p < 0.01). The clinical and microbiological effectiveness as well as the safety were not significantly different between the two treatments. Although daptomycin treatment with a loading dose was associated with lower mortality, the mortality of the treatment (8.3%) did not differ significantly compared to that of the vancomycin treatment (4.1%). Therefore, our findings suggest that vancomycin remains the first-line treatment for hemodialysis patients; however, a loading dose may be beneficial for patients receiving daptomycin.

Functional Differentiation among the Arabidopsis Phosphatidylinositol 4-Phosphate 5-Kinase Genes PIP5K1, PIP5K2 and PIP5K3.

Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) is involved in regulating various cellular processes through the signaling function of its product, phosphatidylinositol (4,5)-bisphosphate. Higher plants encode a large number of PIP5Ks forming distinct clades in their molecular phylogenetic tree. Although biological functions of PIP5K genes have been analyzed intensively in Arabidopsis thaliana, it remains unclear how those functions differ across clades of paralogs. We performed comparative functional analysis of the Arabidopsis genes encoding PIP5K1, PIP5K2 and PIP5K3, of which the first two and the last belong to closely related but distinct clades, to clarify their conserved and/or differentiated functions. Genetic analysis with their single and multiple mutants revealed that PIP5K1 and PIP5K3 have non-overlapping functions, with the former in total plant growth and the latter in root hair elongation, whereas PIP5K2 redundantly functions in both phenomena. This pattern of functional redundancy is explainable in terms of the overlapping pattern of their promoter activities. In transformation rescue experiments, PIP5K3 promoter-directed PIP5K1-YFP completely rescued the short-root-hair phenotype of pip5k3. However, PIP5K3-YFP could substitute for PIP5K1-YFP only partially in rescuing the severe dwarfism of pip5k1pip5k2 when directed by the PIP5K1 promoter. Phylogenetic analysis of angiosperm PIP5Ks revealed that PIP5K3 orthologs have a faster rate of diversification in their amino-acid sequences compared with PIP5K1/2 orthologs after they arose through a eudicot-specific duplication event. These findings suggest that PIP5K3 specialized to promote root hair elongation and lost some of the protein-encoded functions retained by PIP5K1 and PIP5K2, whereas PIP5K1 differentiated from PIP5K2 only in its promoter-directed expression pattern.

CFI 25 Subunit of Cleavage Factor I is Important for Maintaining the Diversity of 3' UTR Lengths in Arabidopsis thaliana (L.) Heynh.

Cleavage and polyadenylation at the 3' end of the pre-mRNA is essential for mRNA function, by regulating its translatability, stability and translocation to the cytoplasm. Cleavage factor I (CFI) is a multi-subunit component of the pre-mRNA 3' end processing machinery in eukaryotes. Here, we report that plant CFI 25 subunit of CFI plays an important role in maintaining the diversity of the 3' ends of mRNA. The genome of Arabidopsis thaliana (L.) Heynh. contained four genes encoding three putative CFI subunits (AtCFI 25, AtCFI 59 and AtCFI 68), orthologous to the mammalian CFI subunits. There were two CFI 25 paralogs (AtCFI 25a and AtCFI 25b) that shared homology with human CFI 25. Two null alleles of AtCFI 25a displayed smaller rosette leaves, longer stigmatic papilla, smaller anther, earlier flowering and lower fertility compared to wild-type plants. Null alleles of AtCFI 25b, as well as, plants ectopically expressing full-length cDNA of AtCFI 25a, displayed no obvious morphological defects. AtCFI 25a was shown to interact with AtCFI 25b, AtCFI 68 and itself, suggesting various forms of CFI in plants. Furthermore, we show that AtCFI 25a function was essential for maintaining proper diversity of the 3' end lengths of transcripts coding for CFI subunits, suggesting a self-regulation of the CFI machinery in plants. AtCFI 25a was also important to maintain 3' ends for other genes to different extent. Collectively, AtCFI 25a, but not AtCFI 25b, seemed to play important roles during Arabidopsis development by maintaining proper diversity of the 3' UTR lengths.

Arabidopsis PLDζ1 and PLDζ2 localize to post-Golgi membrane compartments in a partially overlapping manner.

KEY MESSAGE: Arabidopsis PLDζ1 and PLDζ2 localize to the trans-Golgi network and to compartments including the trans-Golgi network, multi-vesicular bodies, and the tonoplast, respectively, depending on their N-terminal regions containing PX-PH domains. Phospholipase D (PLD) is involved in dynamic cellular processes, including membrane trafficking, cytoskeletal reorganization, and signal transduction for gene expression, through the production of phosphatidic acid in membrane compartments specific to each process. Although PLD plays crucial roles in various plant phenomena, the underlying processes involving PLD for each phenomenon remain largely elusive, partly because the subcellular localization of PLD remains obscure. In this study, we performed comparative subcellular localization analyses of the Arabidopsis thaliana PX-PH-PLDs PLDζ1 and PLDζ2. In mature lateral root cap cells, own promoter-driven fluorescence protein fusions of PLDζ1 localized to the entire trans-Golgi network (TGN) while that of PLDζ2 localized to punctate structures including part of the TGN and multi-vesicular bodies as well as the tonoplast. These localization patterns were reproduced using N-terminal partial proteins, which contain PX-PH domains. An inducibly overexpressed fluorescence protein fusion of the PLDζ2 partial protein first localized to punctate structures, and then accumulated predominantly on the tonoplast. Further domain dissection analysis revealed that the N-terminal moiety preceding the PX-PH domain of PLDζ2 was required for the tonoplast-predominant accumulation. These findings suggest that PLDζ1 and PLDζ2 play partially overlapping but nonetheless distinctive roles in post-Golgi compartments along the membrane trafficking pathway from the TGN to the tonoplast.

Arabidopsis phosphatidylinositol 4-phosphate 5-kinase genes PIP5K7, PIP5K8, and PIP5K9 are redundantly involved in root growth adaptation to osmotic stress.

Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) produces phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2 ), a signaling phospholipid critical for various cellular processes in eukaryotes. The Arabidopsis thaliana genome encodes 11 PIP5K genes. Of these, three type B PIP5K genes, PIP5K7, PIP5K8, and PIP5K9, constitute a subgroup highly conserved in land plants, suggesting that they retain a critical function shared by land plants. In this study, we comprehensively investigated the biological functions of the PIP5K7-9 subgroup genes. Reporter gene analyses revealed their preferential expression in meristematic and vascular tissues. Their YFP-fusion proteins localized primarily to the plasma membrane in root meristem epidermal cells. We selected a mutant line that was considered to be null for each gene. Under normal growth conditions, neither single mutants nor multiple mutants of any combination exhibited noticeable phenotypic changes. However, stress conditions with mannitol or NaCl suppressed main root growth and reduced proximal root meristem size to a greater extent in the pip5k7pip5k8pip5k9 triple mutant than in the wild type. In root meristem epidermal cells of the triple mutant, where plasma membrane localization of the PtdIns(4,5)P2 marker P24Y is impaired to a large extent, brefeldin A body formation is retarded compared with the wild type under hyperosmotic stress. These results indicate that PIP5K7, PIP5K8, and PIP5K9 are not required under normal growth conditions, but are redundantly involved in root growth adaptation to hyperosmotic conditions, possibly through the PtdIns(4,5)P2 function promoting plasma membrane recycling in root meristem cells.

In vitro Neo-Genesis of Tendon/Ligament-Like Tissue by Combination of Mohawk and a Three-Dimensional Cyclic Mechanical Stretch Culture System.

Tendons and ligaments are pivotal connective tissues that tightly connect muscle and bone. In this study, we developed a novel approach to generate tendon/ligament-like tissues with a hierarchical structure, by introducing the tendon/ligament-specific transcription factor Mohawk (MKX) into the mesenchymal stem cell (MSC) line C3H10T1/2 cells, and by applying an improved three-dimensional (3D) cyclic mechanical stretch culture system. In our developed protocol, a combination of stable Mkx expression and cyclic mechanical stretch synergistically affects the structural tendon/ligament-like tissue generation and tendon related gene expression. In a histological analysis of these tendon/ligament-like tissues, an organized extracellular matrix (ECM), containing collagen type III and elastin, was observed. Moreover, we confirmed that Mkx expression and cyclic mechanical stretch, induced the alignment of structural collagen fibril bundles that were deposited in a fibripositor-like manner during the generation of our tendon/ligament-like tissues. Our findings provide new insights for the tendon/ligament biomaterial fields.

Author Correction: PtdIns(3,5)P2 mediates root hair shank hardening in Arabidopsis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Arabidopsis PCaP2 modulates the phosphatidylinositol 4,5-bisphosphate signal on the plasma membrane and attenuates root hair elongation.

Phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] serves as a subcellular signal on the plasma membrane, mediating various cell-polarized phenomena including polar cell growth. Here, we investigated the involvement of Arabidopsis thaliana PCaP2, a plant-unique plasma membrane protein with phosphoinositide-binding activity, in PtdIns(4,5)P2 signaling for root hair tip growth. The long-root-hair phenotype of the pcap2 knockdown mutant was found to stem from its higher average root hair elongation rate compared with the wild type and to counteract the low average rate caused by a defect in the PtdIns(4,5)P2 -producing enzyme gene PIP5K3. On the plasma membrane of elongating root hairs, the PCaP2 promoter-driven PCaP2-green fluorescent protein (GFP), which complemented the pcap2 mutant phenotype, overlapped with the PtdIns(4,5)P2 marker 2xCHERRY-2xPHPLC in the subapical region, but not at the apex, suggesting that PCaP2 attenuates root hair elongation via PtdIns(4,5)P2 signaling on the subapical plasma membrane. Consistent with this, a GFP fusion with the PCaP2 phosphoinositide-binding domain PCaP2N23 , root hair-specific overexpression of which caused a low average root hair elongation rate, localized more intense to the subapical plasma membrane than to the apical plasma membrane similar to PCaP2-GFP. Inducibly overexpressed PCaP2-GFP, but not its derivative lacking the PCaP2N23 domain, replaced 2xCHERRY-2xPHPLC on the plasma membrane in root meristematic epidermal cells, and suppressed FM4-64 internalization in elongating root hairs. Moreover, inducibly overexpressed PCaP2 arrested an endocytic process of PIN2-GFP recycling. Based on these results, we conclude that PCaP2 functions as a negative modulator of PtdIns(4,5)P2 signaling on the subapical plasma membrane probably through competitive binding to PtdIns(4,5)P2 and attenuates root hair elongation.

PtdIns(3,5)P2 mediates root hair shank hardening in Arabidopsis.

Root hairs elongate by tip growth and simultaneously harden the shank by constructing the inner secondary cell wall layer. While much is known about the process of tip growth1, almost nothing is known about the mechanism by which root hairs harden the shank. Here we show that phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)P2), the enzymatic product of FORMATION OF APLOID AND BINUCLEATE CELLS 1 (FAB1), is involved in the hardening of the shank in root hairs in Arabidopsis. FAB1 and PtdIns(3,5)P2 localize to the plasma membrane along the shank of growing root hairs. By contrast, phosphatidylinositol 4-phosphate 5-kinase 3 (PIP5K3) and PtdIns(4,5)P2 localize to the apex of the root hair where they are required for tip growth. Reduction of FAB1 function results in the formation of wavy root hairs while those of the wild type are straight. The localization of FAB1 in the plasma membrane of the root hair shank requires the activity of Rho-related GTPases from plants 10 (ROP10) and localization of ROP10 requires FAB1 activity. Computational modelling of root hair morphogenesis successfully reproduces the wavy root hair phenotype. Taken together, these data demonstrate that root hair shank hardening requires PtdIns(3,5)P2/ROP10 signalling.

Purification and structural analysis of volatile sesquiterpenes produced by Escherichia coli carrying unidentified terpene synthase genes from edible plants of the family Araliaceae.

A simple method to purify volatile sesquiterpenes from recombinant Escherichia coli was developed using the cells that carried known sesquiterpene synthase (Tps) genes ZzZss2 (ZSS2) and ZoTps1. This method was applied for the purification and structural analyses of volatile sesquiterpenes produced by E. coli cells that carried unidentified Tps genes, which were isolated from the Aralia-genus edible plants belonging to the family Araliaceae. Recombinant cells carrying each Tps gene were cultured in the two-layer medium (n-octane/TB medium), and volatile sesquiterpenes trapped in n-octane were purified through two-phase partition, silica gel column chromatography, and reversed-phase preparative high-performance liquid chromatography, if necessary. Further, their structures were confirmed by nuclear magnetic resonance, [α]D, and gas chromatography-mass spectrometry analyses. Herein, the products of E. coli cells that carried two Tps gene (named AcTps1 and AcTps2) in Araria cordata "Udo" and a Tps gene (named AeTps1) in Aralia elata "Taranoki" were studied resulting in identifying functionalities of these cryptic Tps genes.

Correlation Between NKG2DL Expression and Antitumor Effect of Protein-bound Polysaccharide-K in Tumor-bearing Mouse Models.

BACKGROUND/AIM: We investigated the relationship between the expression of natural killer group 2, member D ligands (NKG2DLs) and the antitumor effects of protein-bound polysaccharide-K (PSK). MATERIALS AND METHODS: PSK was administered to evaluate its effectiveness against tumor growth. The expression of Rae-1 and H60 were analyzed in multiple cell lines. RESULTS: PSK showed the highest antitumor effects in mice implanted with cells expressing neither Rae-1 nor H60. PSK had little antitumor effect in mice implanted with cells expressing both Rae-1 and H60. A correlation between the expression of NKG2DLs and the antitumor effect of PSK was observed. After PSK administration, INF-γ production in CD8+ T cells increased in mice with cells expressing neither Rae-1 nor H60, but did not change in mice implanted with cells expressing both Rae-1 and H60. CONCLUSION: We demonstrated that the expression of NKG2DLs affects tumor immunity and the efficacy of immuno therapy in tumor-bearing mouse model.

Relationship between type A behavior patterns and risk of temporomandibular disorder in Japanese undergraduate students.

Objective: Several studies have demonstrated the relationship between temporomandibular disorder (TMD) and emotional stress. Nonetheless, few surveys have examined the relationship between type A behavior patterns and TMD. The aim of this study was to clarify the relationships among TMD, type A behavior patterns, bruxism, and emotional stress in Japanese undergraduate students. Methods: This study was undertaken in Nayoro City, Japan, in 2015, among students of Nayoro City University. The survey was conducted through an anonymous, self-administered, multiple-choice questionnaire. Information was gathered on items evaluating the extent of TMD symptoms, bruxism, type A behavior patterns, and proneness and sensitivity to emotional stress. Results: The questionnaire recovery rate was 31.8% (175/551). There was a high likelihood of TMD in 16.1% of respondents, which is comparable to the findings of previous surveys on Japanese high school students. In keeping with previous studies, we confirmed significant relationships between TMD and both emotional stress and bruxism. A weak but statistically significant association was found between TMD and type A behavior patterns. Conclusion: We propose that TMD may be one of the diseases related to the type A behavior pattern.

A novel-type phosphatidylinositol phosphate-interactive, Ca-binding protein PCaP1 in Arabidopsis thaliana: stable association with plasma membrane and partial involvement in stomata closure.

The Ca(2+)-binding protein-1 (PCaP1) of Arabidopsis thaliana is a new type protein that binds to phosphatidylinositol phosphates and Ca(2+)-calmodulin complex as well as free Ca(2+). Although biochemical properties, such as binding to ligands and N-myristoylation, have been revealed, the intracellular localization, tissue and cell specificity, integrity of membrane association and physiological roles of PCaP1 are unknown. We investigated the tissue and intracellular distribution of PCaP1 by using transgenic lines expressing PCaP1 linked with a green fluorescence protein (GFP) at the carboxyl terminus of PCaP1. GFP fluorescence was obviously detected in most tissues including root, stem, leaf and flower. In these tissues, PCaP1-GFP signal was observed predominantly in the plasma membrane even under physiological stress conditions but not in other organelles. The fluorescence was detected in the cytosol when the 25-residue N-terminal sequence was deleted from PCaP1 indicating essential contribution of N-myristoylation to the plasma membrane anchoring. Fluorescence intensity of PCaP1-GFP in roots was slightly decreased in seedlings grown in medium supplemented with high concentrations of iron for 1 week and increased in those grown with copper. In stomatal guard cells, PCaP1-GFP was strictly, specifically localized to the plasma membrane at the epidermal-cell side but not at the pore side. A T-DNA insertion mutant line of PCaP1 did not show marked phenotype in a life cycle except for well growth under high CO2 conditions. However, stomata of the mutant line did not close entirely even in high osmolarity, which usually induces stomata closure. These results suggest that PCaP1 is involved in the stomatal movement, especially closure process, in leaves and response to excessive copper in root and leaf as a mineral nutrient as a physiological role.

GLABRA2 Directly Suppresses Basic Helix-Loop-Helix Transcription Factor Genes with Diverse Functions in Root Hair Development.

The Arabidopsis thaliana GLABRA2 (GL2) gene encodes a transcription factor involved in the cell differentiation of various epidermal tissues. During root hair pattern formation, GL2 suppresses root hair development in non-hair cells, acting as a node between the gene regulatory networks for cell fate determination and cell differentiation. Despite the importance of GL2 function, its molecular basis remains obscure because the GL2 target genes leading to the network for cell differentiation are unknown. We identified five basic helix-loop-helix (bHLH) transcription factor genes (ROOT HAIR DEFECTIVE6 [RHD6], RHD6-LIKE1 [RSL1], RSL2, Lj-RHL1-LIKE1 [LRL1], and LRL2) as GL2 direct targets using transcriptional and posttranslational induction systems. Chromatin immunoprecipitation analysis confirmed GL2 binding to upstream regions of these genes in planta. Reporter gene analyses showed that these genes are expressed in various stages of root hair development and are suppressed by GL2 in non-hair cells. GL2 promoter-driven GFP fusions of LRL1 and LRL2, but not those of the other bHLH proteins, conferred root hair development on non-hair cells. These results indicate that GL2 directly suppresses bHLH genes with diverse functions in root hair development.

Characteristics of a root hair-less line of Arabidopsis thaliana under physiological stresses.

The plasma membrane-associated Ca(2+)-binding protein-2 of Arabidopsis thaliana is involved in the growth of root hair tips. Several transgenic lines that overexpress the 23 residue N-terminal domain of this protein under the control of the root hair-specific EXPANSIN A7 promoter lack root hairs completely. The role of root hairs under normal and stress conditions was examined in one of these root hair-less lines (NR23). Compared with the wild type, NR23 showed a 47% reduction in water absorption, decreased drought tolerance, and a lower ability to adapt to heat. Growth of NR23 was suppressed in media deficient in phosphorus, iron, calcium, zinc, copper, or potassium. Also, the content of an individual mineral in NR23 grown in normal medium, or in medium lacking a specific mineral, was relatively low. In wild-type plants, the primary and lateral roots produce numerous root hairs that become elongated under phosphate-deficient conditions; NR23 did not produce root hairs. Although several isoforms of the plasma membrane phosphate transporters including PHT1;1-PHT1;6 were markedly induced after growth in phosphate-deficient medium, the levels induced in NR23 were less than half those observed in the wild type. In phosphate-deficient medium, the amounts of acid phosphatase, malate, and citrate secreted from NR23 roots were 38, 9, and 16% of the levels secreted from wild-type roots. The present results suggest that root hairs play significant roles in the absorption of water and several minerals, secretion of acid phosphatase(s) and organic acids, and in penetration of the primary roots into gels.

Protein-bound polysaccharide-K reduces the proportion of regulatory T cells in vitro and in vivo.

Regulatory T cells (Tregs) play an important role in maintaining immunological tolerance. However, this mechanism is one of the major obstacles to overcome when attempting to improve antitumor immunity. Protein-bound polysaccharide­K (PSK) has been used clinically as an antitumor drug, and one of its antitumor mechanisms involves improvement of the tumor-induced immunosuppressive state. Therefore, we investigated whether PSK affects Tregs in vitro and in vivo. In the in vitro study, CD4⁺CD25⁻ cells were separated from normal mouse spleen and cultured with or without PSK in the presence of TGF-ß. Although TGF-ß induced CD4⁺CD25⁺Foxp3⁺ Tregs, PSK reduced the proportion of TGF-ß-induced Tregs. In the in vivo study, BALB/c mice were injected subcutaneously with methylcholanthrene-induced fibrosarcoma (Meth A) cells on day 0, and were administered PSK (50 mg/kg) intraperitoneally from day 1, three times per week. After 4 weeks, the tumor volume, the proportion of Tregs and the CD8+/Treg ratio in the spleen, plasma TGF-ß concentration, and IFN-γ production by spleen cells were measured. PSK significantly reduced tumor growth, the proportion of Tregs in the spleen and the plasma TGF-ß concentration, and significantly increased the CD8+/Treg ratio in the spleen and IFN-γ production by spleen cells. The reduction of the TGF-ß concentration in blood by PSK appears to decrease the proportion of Tregs in lymphoid organs and to augment antitumor immunity.

Rapid structural changes and acidification of guard cell vacuoles during stomatal closure require phosphatidylinositol 3,5-bisphosphate.

Rapid stomatal closure is essential for water conservation in plants and is thus critical for survival under water deficiency. To close stomata rapidly, guard cells reduce their volume by converting a large central vacuole into a highly convoluted structure. However, the molecular mechanisms underlying this change are poorly understood. In this study, we used pH-indicator dyes to demonstrate that vacuolar convolution is accompanied by acidification of the vacuole in fava bean (Vicia faba) guard cells during abscisic acid (ABA)-induced stomatal closure. Vacuolar acidification is necessary for the rapid stomatal closure induced by ABA, since a double mutant of the vacuolar H(+)-ATPase vha-a2 vha-a3 and vacuolar H(+)-PPase mutant vhp1 showed delayed stomatal closure. Furthermore, we provide evidence for the critical role of phosphatidylinositol 3,5-bisphosphate [PtdIns(3,5)P2] in changes in pH and morphology of the vacuole. Single and double Arabidopsis thaliana null mutants of phosphatidylinositol 3-phosphate 5-kinases (PI3P5Ks) exhibited slow stomatal closure upon ABA treatment compared with the wild type. Moreover, an inhibitor of PI3P5K reduced vacuolar acidification and convolution and delayed stomatal closure in response to ABA. Taken together, these results suggest that rapid ABA-induced stomatal closure requires PtdIns(3,5)P2, which is essential for vacuolar acidification and convolution.

The Ca(2+) -binding protein PCaP2 located on the plasma membrane is involved in root hair development as a possible signal transducer.

Plasma membrane-associated Ca(2+) -binding protein-2 (PCaP2) of Arabidopsis thaliana is a novel-type protein that binds to the Ca(2+) /calmodulin complex and phosphatidylinositol phosphates (PtdInsPs) as well as free Ca(2+) . Although the PCaP2 gene is predominantly expressed in root hair cells, it remains unknown how PCaP2 functions in root hair cells via binding to ligands. From biochemical analyses using purified PCaP2 and its variants, we found that the N-terminal basic domain with 23 amino acids (N23) is necessary and sufficient for binding to PtdInsPs and the Ca(2+) /calmodulin complex, and that the residual domain of PCaP2 binds to free Ca(2+) . In mutant analysis, a pcap2 knockdown line displayed longer root hairs than the wild-type. To examine the function of each domain in root hair cells, we over-expressed PCaP2 and its variants using the root hair cell-specific EXPANSIN A7 promoter. Transgenic lines over-expressing PCaP2, PCaP2(G2A) (second glycine substituted by alanine) and ∆23PCaP2 (lacking the N23 domain) exhibited abnormal branched and bulbous root hair cells, while over-expression of the N23 domain suppressed root hair emergence and elongation. The N23 domain was necessary and sufficient for the plasma membrane localization of GFP-tagged PCaP2. These results suggest that the N23 domain of PCaP2 negatively regulates root hair tip growth via processing Ca(2+) and PtdInsP signals on the plasma membrane, while the residual domain is involved in the polarization of cell expansion.