Morphometric approach to address taxonomic problems: The case of Utricularia sect. Foliosa (Lentibulariaceae)

Utricularia sect. Foliosa Kamiénski comprises three recognized species, U. amethystina Salzm. ex A.St.-Hil. & Girard, U. tricolor A.St.-Hil., and U. tridentata Sylvén, delimited based mainly on shape and structure of the corolla. In comparison with the two latter members of the section, U. amethystina forms a complex of morphological variants, reflected taxonomically by the previous recognition of 31 synonyms. In his monograph of the genus, Taylor synonymized these taxa based primarily on his observation of continuous morphological variation of the flowers. In the same treatment he also suggested a future taxonomic re-evaluation could re-establish two, three or more taxa. Here we examine this question utilizing morphometric analyses of floral variation across most of the synonyms mentioned above, within populations from across their Neotropical distribution. Based on both morphological and geographic characters we identify strongly differentiated morphotypes. Our data provide support for both the maintenance of taxa previously recognised as synonyms under U. amethystina, and the resurrection of taxa to species status, namely U. bicolor, U. damazioi, U. lindmanii and U. hirtella, and four other putative new taxa.     

Changes in adhesive and migratory characteristics of hepatocellular carcinoma (HCC) cells induced by expression of alpha3beta1 integrin

The invasive and metastatic potentials of hepatocellular carcinoma are positively correlated with the expression level of alpha3beta1 integrin, a high-affinity adhesion receptor for laminin isoforms including laminin-5. In this study, we investigated changes in the adhesive and invasive behaviors of human HCC HepG2 cells after transfection with cDNA for alpha3 integrin in order to elucidate the direct involvement of this integrin in these cellular processes. We introduced cDNA for splice variants of alpha3 integrin (alpha3A and alpha3B) into the cells, and selected two transfectant clones (HepG2-3A and HepG2-3B), which express the alpha3A and alpha3B integrins, respectively. Both transfectant cells adhered almost equally to laminin-5-coated plates in an alpha3 integrin-dependent manner, indicating that transfected alpha3Abeta1 and alpha3Bbeta1 integrins were functionally active in these cells. The migratory and invasive potentials of the transfectant cells were assessed by scratch wound assay and in vitro chemoinvasion assay. The results demonstrated that the migration of HepG2-3A and HepG2-3B cells but not of mock transfectant (HepG2-M) cells was stimulated on the plates coated with laminin-5. Furthermore, HepG2-3A and HepG2-3B cells were found to be more invasive into laminin-5-containing matrices than were HepG2-M cells. These results strongly suggest that enhanced expression of alpha3beta1 integrin on HCC cells is directly involved in their malignant phenotypes such as invasion and metastasis.     

Role of sphingosine 1-phosphate in the pathogenesis of Sjögren's syndrome

Primary Sj?gren's syndrome (SS) is an autoimmune disease characterized by inflammatory mononuclear cell infiltration and destruction of epithelial cells of lacrimal and salivary glands. Sphingosine 1-phosphate (S1P) and signaling through its receptor S1P(1) have been implicated in many critical cellular events including inflammation, cancer, and angiogenesis. This study was undertaken to examine the role of S1P(1) signaling in the pathogenesis of primary SS. S1P(1) and sphingosine kinase 1, which converts sphingosine to S1P, were detected in the cytoplasm of inflammatory mononuclear cells, vascular endothelial cells, and epithelial cells in all labial salivary glands by immunohistochemistry. The expression of S1P(1) in inflammatory mononuclear cells was enhanced in advanced stages of primary SS. S1P enhanced proliferation and IFN-gamma production by CD4(+) T cells. The enhancing effect of S1P on IFN-gamma production by CD4(+) T cells was stronger in patients with primary SS than in healthy controls. S1P also enhanced Fas expression and Fas-mediated caspase-3 induction in salivary gland epithelial cells. IL-6 expression was detected in the cytoplasm of inflammatory mononuclear cells and ductal epithelial cells and was enhanced in advanced stages of primary SS. Furthermore, both IFN-gamma and S1P augmented IL-6 secretion by salivary gland epithelial cells. These effects of S1P were inhibited by pretreatment of pertussis toxin. Our data reveal that S1P(1) signaling may modulate the autoimmune phenotype of primary SS by the action of immune as well as epithelial cells.     

Increased social interaction in mice deficient of the striatal medium spiny neuron-specific phosphodiesterase 10A2

Cyclic nucleotide phosphodiesterase 10A (PDE10A) is a member of phosphodiesterase families that degrade cAMP and/or cGMP in distinct intracellular sites. PDE10A has a dual activity on hydrolysis of both cAMP and cGMP, and is prominently expressed in the striatum and the testis. Previous studies suggested that PDE10A is involved in regulation of locomotor activity and potentially related to psychosis, but concrete physiological roles of PDE10A remains elusive yet. In this study, we genetically inactivated PDE10A2, a prominent isoform of PDE10A in the brain, in mice, and demonstrate that PDE10A2 deficiency results in increased social interaction without any major influence on different other behaviors, along with increased levels of striatal cAMP. We also demonstrate that PDE10A2 is selectively distributed in medium spiny neurons, but not interneurons, of the striatal complex. Thus, our results establish a physiological role for PDE10A2 in regulating cAMP pathway and social interaction, and suggest that cAMP signaling cascade in striatal medium spiny neurons might be involved in regulating social interaction behavior in mice.     

Temperature variations since the mid-18th century for western Nepal, as reconstructed from tree-ring width and density of Abies spectabilis

The climate of western Nepal was reconstructed for the past 249 years using ring width and wood density of Abies spectabilis (D. Don) Spach from western Nepal. A total of 46 increment core samples were collected from 23 individual trees growing in an open A. spectabilis stand near timberline of 3850 m a.s.l. in Humla District, western Nepal. The core samples were subjected to densitometric analysis to obtain chronologies of ring width and three kinds of intra-annual bulk densities, i.e., minimum, maximum, and mean. Response analysis of tree-ring parameters with climate records revealed that the ring width was correlated negatively with March–May (pre-monsoon) temperature and positively with March–May precipitation, while the minimum density was correlated positively with March–July temperature and negatively with March–May precipitation. On the other hand, the maximum and mean densities were positively correlated with August–September and March–September temperatures, respectively. These results indicate that the ring width and minimum density are primarily controlled by the pre-monsoon temperature and precipitation, while the latewood density by the late monsoon temperature. Finally based on these results of the response analysis, a transfer function was established, with which March–September temperature was reconstructed for the past 249 years, which shows a warming trend from 1750s until approximately 1790, followed by cooling until 1810, then by a gradual warming trend extending to 1950, and a notable cold period continuing up to the present. No evidence of a consistent warming trend over the last century or two commonly appearing in higher latitudes was found in the present reconstruction, but possible factor behind the widespread glacial retreat in the Nepal Himalayas was discussed.     

Streptavidin-based containment systems for genetically engineered microorganisms

The use of genetically modified microorganisms for environmental remediation continues to be debated. Conditional lethal systems with tightly regulated gene expression can be used to contain released microorganisms and ameliorate some of the concerns about horizontal gene transfer. We have described streptavidin-based suicide systems to address these concerns and evaluated their function in Pseudomonas putida containing the TOL plasmid for aromatic hydrocarbon metabolism. Tight regulation of expression of a truncated streptavidin gene was required to avoid premature production of the toxic protein. Streptavidin expression was induced by the absence of 3-methyl benzoate (hydrocarbon substrate) which resulted in the elimination of 99.9% of the bacterial culture within eight hours. Low mutant escape rates at 10(-7) per cell per generation were also realized.     

Metabolic switching of astringent and beneficial triterpenoid saponins in soybean is achieved by a loss‐of‐function mutation in cytochrome P450 72A69

Triterpenoid saponins are major components of secondary metabolites in soybean seeds and are divided into two groups: group A saponins, and 2,3‐dihydro‐2,5‐dihydroxy‐6‐methyl‐4H‐pyran‐4‐one (DDMP) saponins. The aglycone moiety of group A saponins consists of soyasapogenol A (SA), which is an oxidized β‐amyrin product, and the aglycone moiety of the DDMP saponins consists of soyasapogenol B (SB). Group A saponins produce a bitter and astringent aftertaste in soy products, whereas DDMP saponins have known health benefits for humans. We completed map‐based cloning and characterization of the gene Sg‐5, which is responsible for SA biosynthesis. The naturally occurring sg‐5 mutant lacks group A saponins and has a loss‐of‐function mutation (L164*) in Glyma15g39090, which encodes the cytochrome P450 enzyme, CYP72A69. An enzyme assay indicated the hydroxylase activity of recombinant CYP72A69 against SB, which also suggested the production of SA. Additionally, induced Glyma15g39090 mutants (R44* or S348P) lacked group A saponins similar to the sg‐5 mutant, indicating that Glyma15g39090 corresponds to Sg‐5. Endogenous levels of DDMP saponins were higher in the sg‐5 mutant than in the wild‐type lines due to the loss of the enzyme activity that converts SB to SA. Interestingly, the genomes of palaeopolyploid soybean and the closely related common bean carry multiple Sg‐5 paralogs in a genomic region syntenic to the soybean Sg‐5 region. However, SA did not accumulate in common bean samples, suggesting that Sg‐5 activity evolved after gene duplication event(s). Our results demonstrate that metabolic switching of undesirable saponins with beneficial saponins can be achieved in soybean by disabling Sg‐5.