AtFLL2, a member of the FLO2 gene family, affects the enlargement of leaves at the vegetative stage and facilitates the regulation of carbon metabolism and flow.

Arabidopsis thaliana FLL2, a member of the FLO2 gene family, is expressed specifically in green leaves. The fll2 mutant showed significantly large rosette leaves and reduced the chlorophyll content. The sucrose content was significantly reduced. The glucose content was higher during the vegetative growth stage but decreased during the early reproductive growth stage. The amount of assimilated starch was lower than that in the wild type plant. The expression levels of genes involved in biosynthesis of sucrose and starch were largely altered. These results suggest that, in the fll2 mutant, a small amount of photosynthetic products was used for the biosynthesis of starch, and the products were supplied to promote intracellular growth of the source organs or for transport to the sink organs. These findings suggest that FLL2 is a factor affecting the expression level of genes involved in sugar metabolism, whose mutation caused a change in the assimilated products. Abbreviations : DAS: days after sowing.

Arabidopsis thaliana FLO2 is Involved in Efficiency of Photoassimilate Translocation, Which is Associated with Leaf Growth and Aging, Yield of Seeds and Seed Quality.

FLO2, FLOURY ENDOSPERM 2, is highly conserved in higher plants, and rice FLO2 has been predicted to be involved in regulation of accumulation of storage compounds. We analyzed the function of Arabidopsis thaliana FLO2 (AtFLO2) because A. thaliana set structurally different seeds from those of rice. Although the flo2 mutant of A. thaliana showed normal germination, inflorescence and morphogenesis of flowers, peculiar phenotypes on leaves and siliques were observed, suggesting that this gene played important roles during both the vegetative and reproductive stages. The mutant leaves showed a decrease in chloroplast numbers, and increased total biomass with faster growth. When grown in high light intensity conditions, it was observed that aging events were induced. The flo2 mutant showed depressed transportation of photoassimilates into the sink organs. In the reproductive stage, the flo2 mutant had significantly smaller size siliques, causing a reduced yield of seeds. These seeds were structurally weak, and the quality of seeds was significantly lowered, with reduction of accumulation of storage compounds by seeds. A positron-emitting tracer imaging system (PETIS) analysis detected a decreased amount of photoassimilate transport in the flo2 mutant. Therefore, it was presumed that the phenotypes of the flo2 mutant were caused by reduced performance of translocation or transportation of the photoassimilates. Our observation suggests that AtFLO2 is strongly involved in regulation of translocation and transport of assimilates, and contributes greatly to quality control of the various processes involving substance supply or transfer, such as photoassimilation, leaf enlargement, yield of seeds in a silique and accumulation of seed storage compounds.

Evaluation of changes in oxyhemoglobin during Shiritori task in elderly subjects including those with Alzheimer‧s disease.

BACKGROUND: In recent years, as the prevalence of Alzheimer‧s disease (AD) has increased rapidly, demand has increased for early detection and treatment. Therefore, discovery and treatment intervention at the mild cognitive impairment stage are important. Dysfunction of the working memory is known to be conspicuously present in AD patients or mild cognitive impairment subjects from an early stage. Near-infrared spectroscopy (NIRS) is a method to measure hemoglobin concentration changes during an activation task. In the present study, we evaluated the cognitive function of elderly subjects, including those with AD, by means of NIRS. METHODS: The subjects were divided into three groups-the AD group, the intermediate group, and the healthy group (HG)-based on assement of dementia using the Hasegawa‧s Dementia Scale-Revised, Mini-Mental State Examination, and Clinical Dementia Rating. The intermediate group was divided into two groups-the high score group (HSMG) and the low score group (LSMG)-based on Hasegawa‧s Dementia Scale-Revised and Mini-Mental State Examination scores. In this study, during Shiritori tasks using single-event-related NIRS, we analyzed oxyhemoglobin changes in an area, the peak amplitude, and latency, and compared them among four groups: AD group, HSMG, LSMG, and HG. RESULT: In the AD group, the area at left channel (Ch)9, 11, and 19, the area at right Ch22, and the peak ampulitude at left Ch11 and 19 and right Ch5,12, and 22 were significantly smaller than those in HSMG and HG. Furthermore, the latency of the AD group was significantly longer than that of HSMG and HG at all region of interests. However, no significant difference was observed between the AD group and LSMG. CONCLUSION: These findings suggest that analysis of changes in oxyhemoglobin during Shiritori tasks may be a useful neuropsychological index for the early diagnosis of AD. Detailed studies will be conducted in LSMG to facilitate the early introduction of NIRS as a screening tool for cognitive impairment.

Single event-related changes in cerebral oxygenated hemoglobin using word game in schizophrenia.

Neuroimaging studies have been conducted using word generation tasks and have shown greater hypofrontality in patients with schizophrenia compared with healthy subjects. In this study, we compared the characteristics of oxygenated hemoglobin changes involved in both phonological and categorical verbal fluency between 35 outpatients with schizophrenia and 35 healthy subjects during a Japanese "shiritori" task using single-event-related near-infrared spectroscopy. During this task, the schizophrenic patients showed significantly smaller activation in the prefrontal cortex area than the controls. In addition, a significant positive correlation was obtained between oxygenated hemoglobin changes (prefrontal cortex area, inferior parietal area) and the severity of positive psychiatric symptoms. It is possible that hypofrontality of patients may be a diagnostic assistance tool for schizophrenia, and that the relationship between activation and positive syndrome scores may be of help in predicting functional outcome in patients.

Relationships between exploratory eye movement dysfunction and clinical symptoms in schizophrenia.

AIM: Many psychophysiological tests have been widely researched in the search for a biological marker of schizophrenia. The exploratory eye movement (EEM) test involves the monitoring of eye movements while subjects freely view geometric figures. Suzuki et al. (2009) performed discriminant analysis between schizophrenia and non-schizophrenia subjects using EEM test data; consequently, clinically diagnosed schizophrenia patients were identified as having schizophrenia with high probability (73.3%). The aim of the present study was to investigate the characteristics of schizophrenia patients who were identified as having schizophrenia on EEM discriminant analysis (SPDSE) or schizophrenia patients who were identified as not having schizophrenia on EEM discriminant analysis (SPDNSE). METHODS: The data for the 251 schizophrenia subjects used in the previous discriminant-analytic study were analyzed, and the demographic or symptomatic characteristics of SPDSE and SPDNSE were investigated. As for the symptomatic features, a factor analysis of the Brief Psychiatric Rating Scale (BPRS) rating from the schizophrenia subjects was carried out. RESULTS: Five factors were found for schizophrenia symptoms: excitement/hostility; negative symptoms; depression/anxiety; positive symptoms; and disorganization. SPDSE had significantly higher factor scores for excitement/hostility, negative symptoms and disorganization than SPDNSE. Furthermore, the BPRS total score for the SPDSE was significantly higher than that for the SPDNSE. CONCLUSION: SPDSE may be a disease subtype of schizophrenia with severe symptoms related to excitement/hostility, negative symptoms and disorganization, and EEM parameters may detect this subtype. Therefore, the EEM test may be one of the contributors to the simplification of the heterogeneity of schizophrenia.

Characteristics of cortical activation in schizophrenia during the card game "concentration".

Various functional imaging studies have demonstrated reduced lateralization of cortical activation during neurocognitive tasks in schizophrenia. -A well-known card game, "concentration", reflects working memory (WM). We compared characteristics of hemodynamic changes in the prefrontal to temporo-parietal areas of the brain during this card game between 24 outpatients with schizophrenia and 24 age- and gender-matched healthy control subjects. Using multi-channel near-infrared spectroscopy, we measured relative changes in oxygenated hemoglobin concentration (oxy-Hb changes), which reflects brain activity during this task. Patients showed reduced lateralization in the midfrontal area, which is involved in executive functions, and in the inferior parietal area, involved in WM subcomponents. We also found a significant negative correlation between left midfrontal region oxy-Hb changes and severity of negative symptoms of schizophrenia. Our results characterized disease-related features, suggesting the usefulness of oxy-Hb change measurement during this card game for assessing functional outcome in schizophrenic patients.

Exploratory eye movement dysfunction as a discriminator for schizophrenia : a large sample study using a newly developed digital computerized system.

In our previous studies, we identified that exploratory eye movement (EEM) dysfunction appears to be specific to schizophrenia. The availability of a biological marker specific to schizophrenia would be useful for clinical diagnosis of schizophrenia. Consequently, we performed the discriminant analysis between schizophrenics and non-schizophrenics on a large sample using the EEM test data and examined an application of the EEM for clinical diagnosis of schizophrenia. EEM performances were recorded in 251 schizophrenics and 389 non-schizophrenics (111 patients with mood disorders, 28 patients with neurotic disorders and 250 normal controls). The patients were recruited from eight university hospitals and three affiliated hospitals. For this study with a large sample, we developed a new digital computerized version of the EEM test, which automatically handled large amounts of data. We measured four parameters: number of eye fixations (NEF), total eye scanning length (TESL), mean eye scanning length (MESL) and responsive search score (RSS). These parameters of schizophrenics differed significantly from those of the other three groups. The stepwise regression analysis selected the TESL and the RSS as the valid parameters for discriminating between schizophrenics and non-schizophrenics. In the discriminant analysis using the RSS and TESL as prediction parameters, 184 of the 251 clinically diagnosed schizophrenics were discriminated as having schizophrenia (sensitivity 73.3%); and 308 of the 389 clinically diagnosed non-schizophrenic subjects were discriminated as non-schizophrenics (specificity 79.2%). Based on our findings we believe that the EEM measures may be useful for the clinical diagnosis of schizophrenia.

Unraveling Brucella genomics and pathogenesis in immunocompromised IRF-1-/- mice.

PROBLEM: Brucellosis causes abortion in domestic animals and Malta fever in humans. Comparison of Brucella species genomes may reveal potential virulence mechanisms. Engineering bioluminescent Brucella would permit monitoring bacterial dissemination. METHOD OF STUDY: Microarray of the B. melitensis genome allowed comparison of gene content from six Brucella species. Bioluminescent B. melitensis strains were developed using transposon mutagenesis permitting the study of pathogenic Brucella in mice. Monitoring bacterial dissemination as well as organ localization permits evaluating the role of genes and genomic islands in mutant bacteria. RESULTS: Comparative genomic analysis revealed 217 ORFs altered in five Brucella species and were often found in islands. Bioluminescent bacteria disseminated from the injection site to liver, spleen, inguinal lymph nodes, testes and submanibular region. CONCLUSIONS: Genomic islands contribute to Brucella pathogenicity. Biophotonic imaging suggests that Brucella dissemination in mice parallels acute and chronic infections of humans.

Nuclear and mitochondrial localization signals overlap within bovine herpesvirus 1 tegument protein VP22.

VP22, a tegument protein of bovine herpesvirus 1, accumulates in the nucleus of infected and transiently transfected cells. Previous studies indicated a possible regulatory function of VP22 within nuclei, but how VP22 enters nuclei is unknown. Despite the abundance of basic residues within this protein, no classic nuclear localization signal (NLS) motif has been identified. To identify the signal directing nuclear accumulation, a series of truncations, internal deletions, and point mutations were constructed. Fluorescence microscopy of cells transfected with VP22 constructs indicated that a sequence of 103 residues is necessary and sufficient for nuclear localization. This NLS sequence is conformation-sensitive in contrast to a classical sequential NLS. Energy depletion assays and co-immunoprecipitation suggested that this NLS sequence also binds histone H4, resulting in nuclear retention of VP22. In addition, a mitochondrial targeting sequence was identified at the C-terminal 49 amino acids, which overlapped the sequence required for nuclear targeting. Our findings demonstrate the diversity of VP22 protein to localize within the cell and provide the opportunity for VP22 to direct cargo specifically to different subcellular compartments.