Important cytological findings for distinction between follicular variant and conventional papillary thyroid carcinoma, including noninvasive follicular thyroid tumors with papillary-like nuclear features.

We studied cytological specimens of conventional papillary thyroid carcinoma (PTC), follicular variant papillary thyroid carcinoma (FVPTC), and noninvasive follicular thyroid tumor with papillary-like nuclear features (NIFTP) (formerly noninvasive FVPTC) to identify useful cytological parameters for their differentiation. Cytological findings of invasive FVPTC and NIFTP were very similar to each other but differed from those of conventional PTC. Intranuclear cytoplasmic inclusions, true papillary cell clusters, monolayered cell sheets, ropy colloids, multinucleate giant cells, psammoma bodies, and cystic background were the observed characteristic features of conventional PTC.

Detection of abundant megakaryocytes in pulmonary artery blood in lung cancer patients using a microfluidic platform.

Objectives: The lung was recently re-discovered as a hematopoietic organ for platelet production in mice. However, evidence for the role of the lung in thrombopoiesis in humans is still limited. In this study, we examined megakaryocytes in the pulmonary and systemic circulation, specifically in pulmonary arterial blood (PAB), venous blood (PVB) and peripheral blood using a newly developed microfluidic platform for rare cell isolation.

Repression of Nitrogen Starvation Responses by Members of the Arabidopsis GARP-Type Transcription Factor NIGT1/HRS1 Subfamily.

Nitrogen (N) is often a limiting nutrient whose availability determines plant growth and productivity. Because its availability is often low and/or not uniform over time and space in nature, plants respond to variations in N availability by altering uptake and recycling mechanisms, but the molecular mechanisms underlying how these responses are regulated are poorly understood. Here, we show that a group of GARP G2-like transcription factors, NITRATE-INDUCIBLE, GARP-TYPE TRANSCRIPTIONAL REPRESSOR1/HYPERSENSITIVE TO LOW Pi-ELICITED PRIMARY ROOT SHORTENING1 proteins (NIGT1/HRS1s), are factors that bind to the promoter of the N starvation marker and repress an array of N starvation-responsive genes under conditions of high N availability.

Systemic transport of trans-zeatin and its precursor have differing roles in Arabidopsis shoots.

Organ-to-organ signal transmission is essential for higher organisms to ensure coordinated biological reactions during metabolism and morphogenesis. Similar to organs in animals, plant organs communicate by various signalling molecules. Among them, cytokinins, a class of phytohormones, play a key role as root-to-shoot long-distance signals, regulating various growth and developmental processes in shoots.

Arabidopsis Root-Type Ferredoxin:NADP(H) Oxidoreductase 2 is Involved in Detoxification of Nitrite in Roots.

Ferredoxin:NADP(H) oxidoreductase (FNR) plays a key role in redox metabolism in plastids. Whereas leaf FNR (LFNR) is required for photosynthesis, root FNR (RFNR) is believed to provide electrons to ferredoxin (Fd)-dependent enzymes, including nitrite reductase (NiR) and Fd-glutamine-oxoglutarate aminotransferase (Fd-GOGAT) in non-photosynthetic conditions. In some herbal species, however, most nitrate reductase activity is located in photosynthetic organs, and ammonium in roots is assimilated mainly by Fd-independent NADH-GOGAT.

Methylated Cytokinins from the Phytopathogen Rhodococcus fascians Mimic Plant Hormone Activity.

Cytokinins (CKs), a class of phytohormones that regulate plant growth and development, are also synthesized by some phytopathogens to disrupt the hormonal balance and to facilitate niche establishment in their hosts. Rhodococcus fascians harbors the fasciation (fas) locus, an operon encoding several genes homologous to CK biosynthesis and metabolism. This pathogen causes unique leafy gall symptoms reminiscent of CK overproduction; however, bacterial CKs have not been clearly correlated with the severe symptoms, and no virulence-associated unique CKs or analogs have been identified.

Agrobacterium tumefaciens tumor morphology root plastid localization and preferential usage of hydroxylated prenyl donor is important for efficient gall formation.

Upon Agrobacterium tumefaciens infection of a host plant, Tumor morphology root (Tmr) a bacterial adenosine phosphate-isopentenyltransferase (IPT), creates a metabolic bypass in the plastid for direct synthesis of trans-zeatin (tZ) with 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate as the prenyl donor. To understand the biological importance of Tmr function for gall formation, we compared Tmr and Trans-zeatin secretion (Tzs) another agrobacterial IPT that functions within the bacterial cell. Although there is no significant difference in their substrate specificities in vitro, ectopic overexpression of Tzs in Arabidopsis (Arabidopsis thaliana) resulted in the accumulation of comparable amounts of tZ- and N⁶-(Δ²-isopentenyl)adenine (iP)-type cytokinins, whereas overexpression of Tmr resulted exclusively in the accumulation of tZ-type cytokinins.

Functional analyses of LONELY GUY cytokinin-activating enzymes reveal the importance of the direct activation pathway in Arabidopsis.

Cytokinins play crucial roles in diverse aspects of plant growth and development. Spatiotemporal distribution of bioactive cytokinins is finely regulated by metabolic enzymes. LONELY GUY (LOG) was previously identified as a cytokinin-activating enzyme that works in the direct activation pathway in rice (Oryza sativa) shoot meristems.

Structural insight into the reaction mechanism and evolution of cytokinin biosynthesis.

The phytohormone cytokinin regulates plant growth and development. This hormone is also synthesized by some phytopathogenic bacteria, such as Agrobacterium tumefaciens, and is as a key factor in the formation of plant tumors. The rate-limiting step of cytokinin biosynthesis is catalyzed by adenosine phosphate-isopentenyltransferase (IPT).

The exp1 gene essential for pileus expansion and autolysis of the inky cap mushroom Coprinopsis cinerea (Coprinus cinereus) encodes an HMG protein.

The homobasidiomycete Coprinopsis cinerea is a member of the fungi known as inky cap mushrooms, and its fruiting-body pileus autolyzes soon after completion of the development. During the last 3h of the development, the pileus exhibits umbrella-like expansion: the pileal tissue is cracked at the base of each gill and then each gill tissue is split to form a V-shape, as seen in a cross section. We identified two C.

Direct control of shoot meristem activity by a cytokinin-activating enzyme.

The growth of plants depends on continuous function of the meristems. Shoot meristems are responsible for all the post-embryonic aerial organs, such as leaves, stems and flowers. It has been assumed that the phytohormone cytokinin has a positive role in shoot meristem function.

Agrobacterium tumefaciens increases cytokinin production in plastids by modifying the biosynthetic pathway in the host plant.

Agrobacterium tumefaciens infects plants and induces the formation of tumors called "crown galls" by integrating the transferred-DNA (T-DNA) region of the Ti-plasmid into the plant nuclear genome. Tumors are formed because the T-DNA encodes enzymes that modify the synthesis of two plant growth hormones, auxin and cytokinin (CK). Here, we show that a CK biosynthesis enzyme, Tmr, which is encoded by the Agrobacterium T-DNA region, is targeted to and functions in plastids of infected plant cells, despite having no typical plastid-targeting sequence.

AtIPT3 is a key determinant of nitrate-dependent cytokinin biosynthesis in Arabidopsis.

We analyzed the spatial expression pattern of Arabidopsis thaliana adenosine phosphates-isopentenyltransferase genes (AtIPT1, AtIPT3 to AtIPT8) and the effect of inorganic nitrogen sources on their regulation. In mature plants, the AtIPTs were differentially expressed in various tissues including the roots, leaves, stems, flowers and siliques. In transgenic seedlings expressing a gene for green fluorescent protein (GFP) driven by the AtIPT promoters, AtIPT1::GFP was predominantly expressed in the vascular stele of the roots, AtIPT3::GFP was in the phloem companion cells, AtIPT5::GFP was in the lateral root primordium and pericycle, and AtIPT7::GFP was in both the vascular stele and the phloem companion cells of the roots.

Distinct isoprenoid origins of cis- and trans-zeatin biosyntheses in Arabidopsis.

Plants produce the common isoprenoid precursors isopentenyl diphosphate and dimethylallyl diphosphate (DMAPP) through the methylerythritol phosphate (MEP) pathway in plastids and the mevalonate (MVA) pathway in the cytosol. To assess which pathways contribute DMAPP for cytokinin biosynthesis, metabolites from each isoprenoid pathway were selectively labeled with (13)C in Arabidopsis seedlings. Efficient (13)C labeling was achieved by blocking the endogenous pathway genetically or chemically during the feed of a (13)C labeled precursor specific to the MEP or MVA pathways.