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A bottom-up approach was developed to prepare TEMPO radical decorated hollow aromatic frameworks (HPAF-TEMPO) by using TEMPO radical functionalized monomers and SiO2 nanospheres as templates. The accessible inner layer, high density of TEMPO sites, and hybrid micro-/mesopores of the HPAF-TEMPO enable the aerobic oxidation of a broad range of alcohols with high efficiency and excellent selectivity.

Perylene-based organic semiconductors are attractive photoactive materials due to their broad visible-light absorption, large extinction coefficients, high photostability, and relatively low cost. ...

The layer‐by‐layer (LbL) method is a well‐established method for the growth of surface‐attached metal–organic frameworks (SURMOFs). Various experimental parameters, such as surface functionalization or temperature, have been identified as essential in the past. In this study, inspired by these recent insights regarding the LbL SURMOF growth mechanism, the impact of reactant solutions concentration on LbL growth of the Cu2(F4bdc)2(dabco) SURMOF (F4bdc2−=tetrafluorobenzene‐1,4‐dicarboxylate and dabco=1,4‐diazabicyclo‐[2.2.2]octane) in situ by using quartz‐crystal microbalance and ex situ with a combination of spectroscopic, diffraction and microscopy techniques was investigated. It was found that number, size, and morphology of MOF crystallites are strongly influenced by the reagent concentration. By adjusting the interplay of nucleation and growth, we were able to produce densely packed, yet thin films, which are highly desired for a variety of SURMOF applications., Insights from in situ and ex situ investigation on the concentration dependency of the layer‐by‐layer (LbL) growth of metal–organic frameworks on surfaces markedly improve control of the LbL process. Even at reduced cycle numbers, by varying reactant concentrations, densely packed yet thin films could be produced, which are highly desired for various applications.

The role of oligodendrocyte lineage cells, the largest glial population in the adult central nervous system (CNS), in the pathogenesis of Alzheimer’s disease (AD) remains elusive. Here, we developed a culture method for adult oligodendrocyte progenitor cells (aOPCs). Fibroblast growth factor 2 (FGF2) promotes survival and proliferation of NG2+ aOPCs in a serum-free defined medium; a subpopulation (~5%) of plexin-B3+ aOPCs was also found. FGF2 withdrawal decreased NG2+, but increased plexin-B3+ aOPCs and Aβ1-42 secretion. Plexin-B3+ aOPCs were distributed throughout the adult rat brain, although less densely than NG2+ aOPCs. Spreading depolarization induced delayed cortical plexin-B3+ aOPC gliosis in the ipsilateral remote cortex. Furthermore, extracellular Aβ1-42 accumulation was occasionally found around plexin-B3+ aOPCs near the lesions. In AD brains, virtually all cortical SPs were immunostained for plexin-B3, and plexin-B3 levels increased significantly in the Sarkosyl-soluble fractions. These findings suggest that plexin-B3+ aOPCs may play essential roles in AD pathogenesis, as natural Aβ-secreting cells., In order to investigate the role of oligodendrocyte lineage cells in Alzheimer’s Disease (AD) pathology, Nihonmatsu-Kikuchi et al developed a culture method for adult oligodendrocyte progenitor cells in the rat. Using this method as well as imaging AD patient brain tissue, they found that plexin-B3-expressing cells could be a potential source of amyloid β peptide.

Bacterial type III secretion systems assemble the axial structures of both injectisomes and flagella. Injectisome type III secretion systems subsequently secrete effector proteins through their hollow needle into a host, requiring co-ordination. In the Salmonella enterica serovar Typhimurium SPI-2 injectisome, this switch is triggered by sensing the neutral pH of the host cytoplasm. Central to specificity switching is a nonameric SctV protein with an N-terminal transmembrane domain and a toroidal C-terminal cytoplasmic domain. A 'gatekeeper' complex interacts with the SctV cytoplasmic domain in a pH dependent manner, facilitating translocon secretion while repressing effector secretion through a poorly understood mechanism. To better understand the role of SctV in SPI-2 translocon-effector specificity switching, we purified full-length SctV and determined its toroidal cytoplasmic region's structure using cryo-EM. Structural comparisons and molecular dynamics simulations revealed that the cytoplasmic torus is stabilized by its core subdomain 3, about which subdomains 2 and 4 hinge, varying the flexible outside cleft implicated in gatekeeper and substrate binding. In light of patterns of surface conservation, deprotonation, and structural motion, the location of previously identified critical residues suggest that gatekeeper binds a cleft buried between neighboring subdomain 4s. Simulations suggest that a local pH change from 5 to 7.2 stabilizes the subdomain 3 hinge and narrows the central aperture of the nonameric torus. Our results are consistent with a model of local pH sensing at SctV, where pH-dependent dynamics of SctV cytoplasmic domain affect binding of gatekeeper complex., Journal of Structural Biology, 213 (2), ISSN:1047-8477, ISSN:1095-8657

We present a facile protocol for the controlled growth of highly oriented and polyoxometalate-incorporating HKUST-1 SURMOFs. Combining the spin-coating technique with alcohol-vapour induced growth, film thickness, crystallite orientation and crystal size can be precisely tuned. The SURMOFs exhibit excellent abilities in selective adsorption of cationic dyes and water oxidation.

The roles played by oligodendrocyte (OL) lineage cells, the largest glial population in the adult CNS, in the pathogenesis of Alzheimer’s disease (AD) remain elusive. Here, we show a newly developed culture method for adult OL progenitor cells (aOPCs) and identify novel plexin-B3-expressing (plexin-B3+) aOPCs as potential amyloid β peptides (Aβ)-secreting cells. Fibroblast growth factor 2 (FGF2) promotes the survival and proliferation of aOPCs in a serum-free defined medium. Although the whole expression profiles of the expanded aOPCs closely resemble those of in vivo OPCs, we found a subpopulation (up to 5%) of plexin-B3+/olig2+ aOPCs in the cultures growing in FGF2. FGF2 withdrawal decreased NG2+, but increased plexin-B3+ aOPCs with increased APP expression, Aβ1-40, −42 secretions and Aβ1-42/total Aβ ratios in association with cored senile plaque-like morphological changes. In vivo, plexin-B3+ aOPCs are distributed throughout the adult brain, although less densely so than NG2+ aOPCs. Spreading depolarization, a type of brain injury, induced unique delayed cortical plexin-B3+ aOPC gliosis in the ipsilateral, but not in the contralateral, remote cortex. In AD brains, virtually all senile plaques in the cortex were immunostained with plexin-B3 antibodies and the levels of cortical plexin-B3 expression increased significantly in the Salcosyl-soluble fractions. These findings suggest that plexin-B3+ aOPCs play important roles in the pathogenesis of AD most likely as a natural Aβ source.

The role of oligodendrocyte lineage cells, the largest glial population in the adult central nervous system (CNS), in the pathogenesis of Alzheimer's disease (AD) remains elusive. Here, we developed a culture method for adult oligodendrocyte progenitor cells (aOPCs). Fibroblast growth factor 2 (FGF2) promotes survival and proliferation of NG2

Multivariate metal-organic frameworks (MTV-MOFs) incorporating multiple chemical functionalities within single-phase crystalline materials show superior properties that arise from synergistic effects. Herein, we report an efficient and versatile method for the growth of highly oriented multivariate surface-attached MOFs (MTV-SURMOFs) by the combination of the liquid-epitaxial growth method (LPE) and the mixed-linker strategy. Twenty-six MTV-SURMOFs of the [M2L2P] type with a maximum of five different dicarboxylate linkers (L) were deposited onto suitably functionalized surfaces. Systematic studies by infrared reflection absorption (IRRA) spectroscopy and surface XRD provide evidence for the formation of highly oriented MTV-SURMOFs. Interestingly, the pKa's of the dicarboxylate linkers play a crucial role for the orientational quality of the MTV-SURMOFs. In addition, benzene uptake experiments showed that the MTV-SURMOFs exhibit up to 2.6 times higher adsorption capacity as compared to the single-linker SURMOFs, demonstrating the synergistic effects in these surface systems.

Edwardsiella tarda is a Gram-negative enteric pathogen that causes hemorrhagic septicemia in fish and gastro- and extraintestinal infections in humans. The type III secretion system (T3SS) of E. tarda has been identified as a key virulence factor that contributes to pathogenesis in fish. However, little is known about the associated effectors translocated by this T3SS. In this study, by comparing the profile of secreted proteins of the wild-type PPD130/91 and its T3SS ATPase Δ esaN mutant, we identified a new effector by matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry. This effector consists of 1,359 amino acids, sharing high sequence similarity with Orf29/30 of E. tarda strain EIB202, and is renamed EseJ. The secretion and translocation of EseJ depend on the T3SS. A Δ eseJ mutant strain adheres to epithelioma papillosum of carp (EPC) cells 3 to 5 times more extensively than the wild-type strain does. EseJ inhibits bacterial adhesion to EPC cells from within bacterial cells. Importantly, the Δ eseJ mutant strain does not replicate efficiently in EPC cells and fails to replicate in J774A.1 macrophages. In infected J774A.1 macrophages, the Δ eseJ mutant elicits higher production of reactive oxygen species than wild-type E. tarda . The replication defect is consistent with the attenuation of the Δ eseJ mutant in the blue gourami fish model: the 50% lethal dose (LD 50 ) of the Δ eseJ mutant is 2.34 times greater than that of the wild type, and the Δ eseJ mutant is less competitive than the wild type in mixed infection. Thus, EseJ represents a novel effector that contributes to virulence by reducing bacterial adhesion to EPC cells and facilitating intracellular bacterial replication.

Many Gram-negative bacteria utilize a type III secretion system (T3SS) to translocate virulence proteins into host cells to cause diseases. In responding to infection, macrophages detect some of the translocated proteins to activate caspase-1-mediated cell death, called pyroptosis, and secretion of proinflammatory cytokines to control the infection. Edwardsiella tarda is a Gram-negative enteric pathogen that causes hemorrhagic septicemia in fish and both gastrointestinal and extraintestinal infections in humans. In this study, we report that the T3SS of E. tarda facilitates its survival and replication in murine bone marrow-derived macrophages, and E. tarda infection triggers pyroptosis of infected macrophages from mice and fish and increased secretion of the cytokine interleukin 1β in a T3SS-dependent manner. Deletion of the flagellin gene fliC of E. tarda results in decreased cytotoxicity for infected macrophages and does not attenuate its virulence in a fish model of infection, whereas upregulated expression of FliC in the fliC mutant strain reduces its virulence. We propose that the host controls E. tarda infection partially by detecting FliC translocated by the T3SS, whereas the bacteria downregulate the expression of FliC to evade innate immunity.

The relationship between depression and Alzheimer's disease (AD) has always been relevant and controversial. Here, we briefly review epidemiological and biological studies that have investigated these disorders and then introduce our recent research about postmortem brains from patients with major depressive disorder (MDD). Our novel methodological approaches have revealed that MDD may be associated with an unknown type of myelin/myelination abnormalities in the frontopolar cortex. Based mainly on our findings, as well as on neuropathological observations by Braak and Braak (Acta Neuropathol 9, 197-201, 1996), we discuss the possible existence of an as yet unknown common mechanism linking the pathophysiologies underlying both depression and AD.

Flexible in many aspects: inkjet printing of metal-organic frameworks permits their larger area, high-resolution deposition in any desired pattern, even in the form of gradients or shades. When flexible substrates are used, many applications can be envisioned, such as sensing and capture of hazardous gases for personal safety measures.

Following infection of mammalian cells, Salmonella enterica serovar Typhimurium (S. Typhimurium) replicates within membrane-bound compartments known as Salmonella-containing vacuoles (SCVs). The Salmonella pathogenicity island 2 type III secretion system (SPI-2 T3SS) translocates approximately 30 different effectors across the vacuolar membrane. SseF and SseG are two such effectors that are required for SCVs to localize close to the Golgi network in infected epithelial cells. In a yeast two-hybrid assay, SseG and an N-terminal variant of SseF interacted directly with mammalian ACBD3, a multifunctional cytosolic Golgi network-associated protein. Knockdown of ACBD3 by small interfering RNA (siRNA) reduced epithelial cell Golgi network association of wild-type bacteria, phenocopying the effect of null mutations of sseG or sseF. Binding of SseF to ACBD3 in infected cells required the presence of SseG. A single-amino-acid mutant of SseG and a double-amino-acid mutant of SseF were obtained that did not interact with ACBD3 in Saccharomyces cerevisiae. When either of these was produced together with the corresponding wild-type effector by Salmonella in infected cells, they enabled SCV-Golgi network association and interacted with ACBD3. However, these properties were lost and bacteria displayed an intracellular replication defect when cells were infected with Salmonella carrying both mutant genes. Knockdown of ACBD3 resulted in a replication defect of wild-type bacteria but did not further attenuate the growth defect of a ΔsseFG mutant strain. We propose a model in which interaction between SseF and SseG enables both proteins to bind ACBD3, thereby anchoring SCVs at the Golgi network and facilitating bacterial replication. IMPORTANCE Upon invasion of epithelial cells, the majority of vacuoles containing Salmonella enterica migrate to the perinuclear region-located Golgi network and remain in this region of the cell during the first few rounds of bacterial replication, forming a clustered microcolony of vacuoles. This process requires the action of SseF and SseG, two effector proteins that are translocated by the Salmonella SPI-2 type III secretion system. However, little is known about how they function. Here, we show that both proteins interact with the mammalian Golgi network-associated protein ACBD3. To our knowledge, the SseF-SseG-ACBD3 interaction is the first example of a tethering complex between a pathogen-containing vacuole and a host cell organelle.

As well-oriented, surface-bound metal-organic frameworks become the centerpiece of many new applications, a profound understanding of their growth mode becomes necessary. This work shows that the currently favored model of surface templating is in fact a special case valid only for systems with a more or less cubic crystal shape, while in less symmetric systems crystal ripening and minimization of surface energies dominate the growth process.

Cytosol, Salmonella , and pH Salmonella and other bacterial pathogens grow inside animal host cells within intracellular vacuoles. The bacteria secrete effector proteins across the vacuole membrane, altering the host-cell physiology to the pathogen's advantage. The secretion process involves a specialized secretory apparatus, the type III secretion system, whose assembly is triggered by the low pH within the host-cell vacuole. Now, Yu et al. (p. 1040 , published online 15 April; see the Perspective by Collier ) have identified neutral pH as a physiological signal for effector translocation by intracellular Salmonella . The process involves the disassembly of a membrane-bound regulatory complex that is also found in other animal pathogens. Thus, Salmonella exploits the low pH of the vacuole as a signal to induce assembly of the secretion system, and then the neutral pH of the cytoplasm to trigger effector translocation.

During the systemic phase of murine infection with Salmonella enterica serovar Typhimurium, bacterial virulence is correlated with the ability to grow and survive within host macrophages. Salmonella pathogenicity island 2 (SPI-2), encoding a type three secretion system, has emerged as an important contributor to Salmonella intracellular growth. SPI-2 mutants have been proposed to be more accessible than wild-type Salmonella to oxyradicals generated by the NADPH phagocyte oxidase. We performed mixed infections of mice to investigate the relationship between SPI-2 and SlyA, a transcriptional regulator that confers resistance to oxyradicals. In mixed-infection experiments, the SPI-2 null mutant was severely attenuated in virulence, whereas slyA mutants were only mildly attenuated. Surprisingly, further experiments indicated that the function of SPI-2 was partially dependent on slyA . The intracellular behavior of a slyA mutant in infected cells was consistent with inefficient SPI-2 expression, as formation of Salmonella -induced filaments and the intracellular F-actin meshwork, features that depend on SPI-2, were present at abnormally low frequencies. Furthermore, the translocated levels of the SPI-2 effector SseJ were severely reduced in a strain carrying a mutation in slyA . We used flow cytometry to investigate the role of SlyA in expression of green fluorescent protein (GFP) from transcriptional fusions with promoters of either of two other SPI-2 effector genes, sifB and sifA . The slyA mutant exhibited reduced GFP expression from both promoters. Combining mutations in slyA and other regulators of SPI-2 indicated that SlyA acts through the SsrAB two-component regulatory system. SlyA exhibits partial functional redundancy with OmpR-EnvZ and contributes to the transcriptional response to low osmolarity and the absence of calcium, two environmental stimuli that promote SPI-2 gene expression.

Summary Replication of Salmonella typhimurium in host cells depends in part on the action of the Salmonella Pathogenicity Island 2 (SPI-2) type III secretion system (TTSS), which translocates bacterial effector proteins across the membrane of the Salmonella-containing vacuole (SCV). We have shown previously that one activity of the SPI-2 TTSS is the assembly of a coat of F-actin in the vicinity of bacterial microcolonies. To identify proteins involved in SPI-2 dependent actin polymerization, we tested strains carrying mutations in each of several genes whose products are proposed to be secreted through the SPI-2 TTSS, for their ability to assemble F-actin around intracellular bacteria. We found that strains carrying mutations in either sseB, sseC, sseD or spiC were deficient in actin assembly. The phenotypes of the sseB-, sseC- and sseD– mutants can be attributed to their requirement for translocation of SPI-2 effectors. SpiC was investigated further in view of its proposed role as an effector. Transient expression of a myc::SpiC fusion protein in Hela cells did not induce any significant alterations to the host cell cytoskeleton, and failed to restore actin polymerization around intracellular spiC– mutant bacteria. However, the same protein did complement the mutant phenotype when expressed from a plasmid within bacteria. Furthermore, spiC was found to be required for SPI-2 mediated secretion of SseB, SseC and SseD in vitro. An antibody against SpiC detected the protein on immunoblots from total cell lysates of S. typhimurium expressing SpiC from a plasmid, but it was not detected in secreted fractions after exposure of cells to conditions that result in secretion of other SPI-2 effector proteins. Investigation of the trafficking of SCVs containing a spiC– mutant in macrophages revealed only a low level of association with the lysosomal marker cathepsin D, similar to that of wild-type bacteria. Together, these results show that SpiC is involved in the process of SPI-2 secretion and indicate that phenotypes associated with a spiC- mutant are caused by the inability of this strain to translocate effector proteins, thus calling for further investigation into the function(s) of this protein.

The Salmonella pathogenicity island 2 (SPI-2) type III secretion system (TTSS) of Salmonella typhimurium is required for bacterial replication within host cells. It acts by translocating effector proteins across the membrane of the Salmonella-containing vacuole (SCV). The SifA effector is required to maintain the integrity of the SCV membrane, and for the formation in epithelial cells of Salmonella-induced filaments (Sifs), which are tubular extensions of SCVs. We have investigated the role in S. typhimurium virulence of the putative SPI-2 effector genes sifB, srfJ, sseJ and sseI. An S. typhimurium strain carrying a mutation in sseJ was mildly attenuated for systemic virulence in mice, but strains carrying mutations in either srfJ, sseI or sifB had very little or no detectable virulence defect after intraperitoneal inoculation. Expression of SseJ in HeLa cells resulted in the formation of globular membranous compartments (GMCs), the composition of which appears to be similar to that of SCV membranes and Sifs. The formation of GMCs was dependent on the serine residue of the predicted acyltransferase/lipase active site of SseJ. Transiently expressed SseJ also inhibited Sif formation by wild-type bacteria, and was found to associate with Sifs, SCV membranes and simultaneously expressed SifA. Intracellular vacuoles containing sseJ mutant bacteria appeared normal but, in contrast to a sifA mutant, a sifA sseJ double mutant strain did not lose its vacuolar membrane, indicating that loss of vacuolar membrane around sifA mutant bacteria requires the action of SseJ. Collectively, these results suggest that the combined action of SseJ and SifA regulate dynamics of the SCV membrane in infected cells.

Background: The C-ring has a crucial role in bacterial type III secretion. Results: Salmonella ssaQ produces two proteins by tandem translation: a short protein binds to its corresponding region within the larger putative C-ring protein and stabilizes it. Conclusion: SsaQ function is optimized by a novel chaperone-like protein, produced by tandem translation from its own mRNA. Significance: The data increase the understanding of type III secretion., Type III secretion systems (T3SSs) of bacterial pathogens involve the assembly of a surface-localized needle complex, through which translocon proteins are secreted to form a pore in the eukaryotic cell membrane. This enables the transfer of effector proteins from the bacterial cytoplasm to the host cell. A structure known as the C-ring is thought to have a crucial role in secretion by acting as a cytoplasmic sorting platform at the base of the T3SS. Here, we studied SsaQ, an FliN-like putative C-ring protein of the Salmonella pathogenicity island 2 (SPI-2)-encoded T3SS. ssaQ produces two proteins by tandem translation: a long form (SsaQL) composed of 322 amino acids and a shorter protein (SsaQS) comprising the C-terminal 106 residues of SsaQL. SsaQL is essential for SPI-2 T3SS function. Loss of SsaQS impairs the function of the T3SS both ex vivo and in vivo. SsaQS binds to its corresponding region within SsaQL and stabilizes the larger protein. Therefore, SsaQL function is optimized by a novel chaperone-like protein, produced by tandem translation from its own mRNA species.

To explore the effect of long-chain polyunsaturated fatty acids (LPFA) on the survival and process growth of the brain hippocampal Oligodendrocyte precursor cells (OPC).Two kinds of cultured neural progenitor cells isolated from adult rat hippocampus were used. After arachidonic acid (AA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) treatment respectively, the activity of cells were determined by Lactate dehydrogenase (LDH) assay, and the quantitative measurements of the cell processes were done after the fluorescent immune cells staining.EPA, DHA and AA showed similar trends to increase the cell numbers when the concentrations were high (50 micromol/L, P0.05), but only EPA and DHA elongated the process of OPC significantly (P0.05).omega-3 LPFA (EPA and DHA) could enhance the survival and process growth of OPC.

The type III secretion system (TTSS) encoded by Salmonella Pathogenicity Island 2 (SPI-2) is required for systemic infection and intracellular replication of Salmonella enterica serovar Typhimurium. The SPI-2 TTSS is activated after internalization of bacteria by host cells, and translocates effector proteins into and across the vacuolar membrane, where they interfere with several host cell functions. Here, we investigated the function of SsaM, a small protein encoded within SPI-2. An ssaM deletion mutant had virulence and intracellular replication defects comparable to those of a SPI-2 TTSS null mutant. Although the ssaM mutant was able to secrete the effector protein SseJ in vitro, it failed to translocate SseJ into host cells, and to secrete the translocon proteins SseB, SseC and SseD in vitro. This phenotype is similar to that of a strain carrying a mutation in the SPI-2 gene spiC, whose product is reported to be an effector involved in trafficking of the Salmonella vacuole in macrophages. Both ssaM and spiC mutants were found to oversecrete the SPI-2 effector proteins SseJ and PipB in vitro. Fractionation assays and immunofluorescence microscopy were used to investigate the localization of SsaM and SpiC in macrophages. No evidence for translocation of these proteins was obtained. The similar phenotypes of the ssaM and spiC mutants suggested that they might be involved in the same function. Pull-down and co-immune precipitation experiments showed that SpiC and SsaM interact within the bacterial cell. We propose that a complex involving SsaM and SpiC distinguishes between translocators and effector proteins, and controls their ordered secretion through the SPI-2 TTSS.

The type III secretion system (TTSS) encoded by theSalmonellapathogenicity island 2 (SPI-2) is required for bacterial replication inside macrophages and for systemic infection in mice. Many TTSS secreted proteins, including effectors and components of the translocon, require chaperones which promote their stability, prevent their premature interactions or facilitate their secretion. In this study, the function of the first gene (sseA) of one of the SPI-2 operons (sseA–G) was investigated. This operon includes genes that encode translocon components (SseB, SseC and SseD), translocated proteins (SseF and SseG) and putative chaperones (SscA and SscB).sseAencodes a 12·5 kDa protein with a C-terminal region with the potential to form a coiled-coil structure, but no sequence similarity to other proteins. Mutation ofsseAresults in severe virulence attenuation and an intracellular replication defect. It is shown here that SseA is not a secreted protein, but is required for SPI-2-dependent translocation of two effector proteins (SifA and PipB). Furthermore, the translocon components SseB and SseD were not detected in ansseAmutant strain. By using a yeast two-hybrid assay and column binding experiments, it is demonstrated that SseA interacts directly with SseB and SseD. These results indicate that SseA is a chaperone for SseB and SseD. The inability of ansseAmutant to assemble the SPI-2 TTSS translocon accounts for its high level of virulence attenuationin vivo. To the authors' knowledge, this is the first chaperone described for the SPI-2 TTSS.

The Salmonella pathogenicity island 2 (SPI-2) type III secretion system (TTSS) of Salmonella typhimurium is required for bacterial replication within host cells. It acts by translocating effector proteins across the membrane of the Salmonella-containing vacuole (SCV). The SifA effector is required to maintain the integrity of the SCV membrane, and for the formation in epithelial cells of Salmonella-induced filaments (Sifs), which are tubular extensions of SCVs. We have investigated the role in S. typhimurium virulence of the putative SPI-2 effector genes sifB, srfJ, sseJ and sseI. An S. typhimurium strain carrying a mutation in sseJ was mildly attenuated for systemic virulence in mice, but strains carrying mutations in either srfJ, sseI or sifB had very little or no detectable virulence defect after intraperitoneal inoculation. Expression of SseJ in HeLa cells resulted in the formation of globular membranous compartments (GMCs), the composition of which appears to be similar to that of SCV membranes and Sifs. The formation of GMCs was dependent on the serine residue of the predicted acyltransferase/lipase active site of SseJ. Transiently expressed SseJ also inhibited Sif formation by wild-type bacteria, and was found to associate with Sifs, SCV membranes and simultaneously expressed SifA. Intracellular vacuoles containing sseJ mutant bacteria appeared normal but, in contrast to a sifA mutant, a sifA sseJ double mutant strain did not lose its vacuolar membrane, indicating that loss of vacuolar membrane around sifA mutant bacteria requires the action of SseJ. Collectively, these results suggest that the combined action of SseJ and SifA regulate dynamics of the SCV membrane in infected cells.

Bipolar and major depressive disorders are essentially relapsing and remitting disorders of affect with nearly full recovery between episodes. Although the underlying molecular mechanisms remain unclear, myelin-related abnormalities have long been suspected. Here, using novel statistical analysis, we show that subtle but significant abnormalities exist in the composition of fatty acids (FAs), including docosapentaenoic acid (22:5n-3), one of the omega-3 polyunsaturated FAs, found in the post-mortem frontopolar cortex (FPC) of subjects with bipolar or major depressive disorders, although not in those with schizophrenia. These abnormalities were all aggravated in a myelin level-dependent manner, suggesting their close relationship with myelination. Animal studies have further revealed that chronic antidepressant treatment induces robust changes in brain FA metabolism, but contributes only part of the abnormalities found in the affective disorder brains. These findings indicate that the pathophysiology of affective disorders involves an unknown type of perturbed myelination in the FPC that may serve as a novel diagnostic and therapeutic target.

Recent studies suggest that schizophrenia (SCH) and bipolar disorder (BPD) may share a similar etiopathology. However, their precise neuropathological natures have rarely been characterized in a comprehensive and quantitative fashion. We have recently developed a rapid, quantitative cell-counting method for frozen unfixed postmortem brains using a flow cytometer. In the present study, we not only counted stained nuclei, but also measured their sizes in the gray matter of frontopolar cortices (FPCs) and inferior temporal cortices (ITCs) from patients with SCH or BPD, as well as in that from normal controls. In terms of NeuN(+) neuronal nuclei size, particularly in the reduced densities of small NeuN(+) nuclei, we found abnormal distributions present in the ITC gray matter of both patient groups. These same abnormalities were also found in the FPCs of SCH patients, whereas in the FPCs of BPD patients, a reduction in oligodendrocyte lineage (olig2(+)) cells was much more common. Surprisingly, in the SCH FPC, normal left-greater-than-right asymmetry in neural nuclei densities was almost completely reversed. In the BPD FPC, this asymmetry, though not obvious, differed significantly from that in the SCH FPC. These findings indicate that while similar neuropathological abnormalities are shared by patients with SCH or BPD, differences also exist, mainly in the FPC, which may at least partially explain the differences observed in many aspects in these disorders.