Structural aspects of cypsela and seed development of Trichocline catharinensis (Cabrera): a Brazilian endemic species.

This is the first study to describe in a timescale morphohistological and ultrastructural characteristics of fruit (cypsela) and seed development in Trichocline catharinensis, which was completed 21 days after anthesis (DAA). At anthesis, we identified an ovary with three differentiated regions, including the inner epidermis, inner part, and outer epidermis. The mature ovule showed an integument with the outer epidermis, integumentary parenchyma, and endothelium. Cells around the endothelium form the periendothelial zone with thick cell walls that showed Periodic acid-Schiff (PAS)-positive reaction. The periendothelial zone and endothelium showed degradation of the cells during embryogenesis. The main stages of embryo development from fecundation through mature seed were identified. The ripe cypsela showed the pericarp (exocarp), seed coat (exotesta), and remaining endosperm surrounding the embryo. Mature embryos were straight with shoot apical meristem (SAM), and root apical meristem (RAM) was separated by the hypocotyl. Light microscopy (LM) and transmission electron microscopy (TEM) analyses indicate cells with characteristics of meristem cells, as well as proteins and lipid bodies and mitochondria with few cristae in cotyledon cells. Our findings provide insight into taxonomic and physiological studies by detailing cypsela and seed ontogenesis from an endemic and vulnerable Asteraceae from southern Brazil. This study is also a starting point for establishing the biological criteria for seed harvesting and future studies of seed physiology and conservation of plant genetic resource.

Effects of Ultraviolet Radiation (UV-A+UV-B) on the Antioxidant Metabolism of the Red Macroalga Species Acanthophora spicifera (Rhodophyta, Ceramiales) From Different Salinity and Nutrient Conditions.

Acanthophora spicifera (M.Vahl) Børgesen is a macroalga of great economic importance. This study evaluated the antioxidant responses of two algal populations of A. spicifera adapted to different abiotic conditions when exposed to ultraviolet-A+ultraviolet-B radiation (UV-A+UV-B). Experiments were performed using the water at two collection points for 7 days of acclimatization and 7 days of exposure to UVR (3 h per day), followed by metabolic analyses. At point 1, water of 30 ± 1 practical salinity unit (psu) had concentrations of 1.06 ± 0.27 mm NH 4 + , 8.47 ± 0.01 mm NO 3 - , 0.17 ± 0.01 mm PO 4 - 3 and pH 7.88. At point 2, water of 35 ± 1 psu had concentrations of 1.13 ± 0.05 mm NH 4 + , 3.73 ± 0.01 mm NO 3 - , 0.52 ± 0.01 mm PO 4 - 3 and pH 8.55. Chlorophyll a, phycobiliproteins, carotenoids, mycosporins, polyphenolics and antioxidant enzymes (catalase, superoxide dismutase and guaiacol peroxidase) were evaluated. The present study demonstrates that ultraviolet radiation triggers antioxidant activity in the A. spicifera. However, such activation resulted in greater responses in samples of the point 1, with lower salinity and highest concentration of nutrients.

Anatomical and biochemical changes associated with thedevelopment and germination of Araucaria angustifolia seeds

This study aimed at assessing the cell cycle, and anatomical and biochemical changes that the embryonic axis of Araucaria angustifolia undergoes during development, focusing on the maturation stage. During all development, cells exhibited intense metabolic activity with an abundance of mitochondria, lipid bodies, and vacuolated cells. The continued accumulation of starch and protein was observed by LM and TEM and indicated by spectra of FTIR. Cell differentiation of the procambium was observed with a thickening of the cell wall and the formation of resiniferous ducts. At Stage III and IV, cells exhibited structural changes such as altered or elongated mitochondria and presence of plastoglobules. These results suggest that there is a gradual transition from developmental metabolism to germination metabolism. Such changes can contribute to the rapid germination of seeds right after their dispersion, making it an ecological strategy to reduce post-dispersal exposure to predators and to avoid damage from reduced moisture.

Ocean warming and copper pollution: implications for metabolic compounds of the agarophyte Gelidium floridanum (Gelidiales, Rhodophyta).

Ocean warming is increasing and scientific predictions suggest a rise of up to 4°C in sea water temperatures. The combination of a polluted and warmer environment may be detrimental for aquatic species, especially for primary producers such as seaweeds. This study investigated the potential for interactive effects of an increased seawater temperature in a copper-rich environment on the photosynthetic pigments and metabolic compounds of the red seaweed Gelidium floridanum. Seaweed samples were cultivated in a factorial design with temperature (24°C and 30°C), copper (0 and 3 µM), and time (7 and 14 d). The exposure of G. floridanum to copper and 30°C for 7 d resulted in a lower concentration of chlorophyll a, smaller phycobiliprotein rods and lower concentration of soluble sugars. After 14 d of cultivation, a higher concentration of chlorophyll a and soluble sugars could be observed on seaweeds cultivated under 30°C. The accumulation of carotenoids and the release of phenolic compounds indicated specific protective mechanisms against temperature and copper, respectively. Overall, seaweeds grew less when exposed to copper 3 µM at 30°C.

Morphological and functional characterization of the hemocytes from the pearl oyster Pteria hirundo and their immune responses against Vibrio infections.

Hemocyte populations of the pearl oyster Pteria hirundo were characterized at morphological, ultrastructural and functional levels. Three main hemocyte populations were identified: hyalinocytes, granulocytes and blast-like cells. Hyalinocytes were the most abundant population (88.2%) characterized by the presence of few or no granules in the cytoplasm and composed by two subpopulations, large and small hyalinocytes. Comparatively, granulocytes represented 2.2% of the hemocyte population and were characterized by the presence of numerous large electron-lucid granules in the cytoplasm. Finally, the blast-like cells (9.5%) were the smallest hemocytes, showing spherical shape and a high nucleus/cytoplasm ratio. Hemocytes exhibited a significant phagocytic capacity for inert particles (38.5%) and showed to be able to produce microbicidal molecules, such as reactive oxygen species (ROS) (ex vivo assays). The immune role of hemocytes was further investigated in the P. hirundo defense against the Gram-negative Vibrio alginolyticus. A significant decrease in the total number of hemocytes was observed at 24 h following injection of V. alginolyticus or sterile seawater (injury control) when compared to naïve (unchallenged) animals, indicating the migration of circulating hemocytes to the sites of infection and tissue damage. Bacterial agglutination was only observed against Gram-negative bacteria (Vibrio) but not against to marine Gram-positive-bacteria. Besides, an increase in the agglutination titer was observed against V. alginolyticus only in animals previously infected with this same bacterial strain. These results suggest that agglutinins or lectin-like molecules may have been produced in response to this particular microorganism promoting a specific recognition. The ultrastructural and functional characterization of P. hirundo hemocytes constitutes a new important piece of the molluscan immunity puzzle that can also contribute for the improvement of bivalve production sustainability.

Metabolomics of Ulva lactuca Linnaeus (Chlorophyta) exposed to oil fuels: Fourier transform infrared spectroscopy and multivariate analysis as tools for metabolic fingerprint.

Fossil fuels, e.g. gasoline and diesel oil, account for substantial share of the pollution that affects marine ecosystems. Environmental metabolomics is an emerging field that may help unravel the effect of these xenobiotics on seaweeds and provide methodologies for biomonitoring coastal ecosystems. In the present study, FTIR and multivariate analysis were used to discriminate metabolic profiles of Ulva lactuca after in vitro exposure to diesel oil and gasoline, in combinations of concentrations (0.001%, 0.01%, 0.1%, and 1.0% - v/v) and times of exposure (30min, 1h, 12h, and 24h). PCA and HCA performed on entire mid-infrared spectral window were able to discriminate diesel oil-exposed thalli from the gasoline-exposed ones. HCA performed on spectral window related to the protein absorbance (1700-1500cm-1) enabled the best discrimination between gasoline-exposed samples regarding the time of exposure, and between diesel oil-exposed samples according to the concentration. The results indicate that the combination of FTIR with multivariate analysis is a simple and efficient methodology for metabolic profiling with potential use for biomonitoring strategies.

In vitro exposure of Ulva lactuca Linnaeus (Chlorophyta) to gasoline - Biochemical and morphological alterations.

Refined fuels have considerable share of pollution of marine ecosystems. Gasoline is one of the most consumed fuel worldwide, but its effects on marine benthic primary producers are poorly investigated. In this study, Ulva lactuca was chosen as a biological model due to its cosmopolitan nature and tolerance to high levels and wide range of xenobiotics and our goal was to evaluate the effects of gasoline on ultrastructure and metabolism of that seaweed. The experimental design consisted of in vitro exposure of U. lactuca to four concentrations of gasoline (0.001%, 0.01%, 0.1%, and 1.0%, v/v) over 30 min, 1 h, 12 h, and 24 h, followed by cytochemical, SEM, and biochemical analysis. Increase in the number of cytoplasmic granules, loss of cell turgor, cytoplasmic shrinkage, and alterations in the mucilage were some of the ultrastructural alterations observed in thalli exposed to gasoline. Decrease in carotenoid and polyphenol contents, as well as increase of soluble sugars and starch contents were associated with the time of exposure to the xenobiotic. In combination, the results revealed important morphological and biochemical alterations in the phenotype of U. lactuca upon acute exposure to gasoline. This seaweed contain certain metabolites assigned as candidates to biomarkers of the environmental stress investigated and it is thought to be a promise species for usage in coastal ecosystems perturbation monitoring system. In addition, the findings suggest that U. lactuca is able to metabolize gasoline hydrocarbons and use them as energy source, acting as bioremediator of marine waters contaminated by petroleum derivatives.

Triterpene derivative: A potential signaling pathway for the fern-9(11)-ene-2α,3ß-diol on insulin secretion in pancreatic islet.

AIM: Triterpenes and their derivatives influence on carbohydrate metabolism. In vivo and in vitro treatment investigated the effect of the natural triterpene fern-9(11)-ene-2α,3ß-diol (1), isolated from Croton heterodoxus, and a derivative triterpene (2) on glucose homeostasis. MAIN METHODS: The antidiabetic effect of the crude extract from C. heterodoxus leaves, the natural triterpene (1) as well as the derivative triterpene (2) were assayed on glucose tolerance. The effect and the mechanism of action on in vivo treatment with triterpene 2 on glycaemia and insulin secretion were studied. In addition, in vitro studies investigated the mechanism of triterpene 2 on glucose uptake and calcium influx on insulin secretion in pancreatic islets. KEY FINDINGS: The results show the extract slightly reduced the glycaemia when compared with hyperglycemic group. However, the presence of the substituent electron-withdrawing 4-nitrobenzoyl group in the A-ring of triterpene 2 powered the serum glucose lowering compared to triterpene 1. In addition, in vivo treatment with triterpene 2 significantly increased the insulin secretion induced by glucose and stimulated the glucose uptake and calcium influx in pancreatic islet. The effect of triterpene on calcium influx was completely inhibited by diazoxide, nifedipine and stearoylcarnitine treatment. SIGNIFICANCE: The stimulatory effect of triterpene 2 on glucose uptake, calcium influx, regulation of potassium (K(+)-ATP) and calcium (L-VDCCs) channels activity as well as the pathway of PKC highlights the mechanism of action of the compound in pancreatic islets on insulin secretion and glucose homeostasis. In addition, this compound did not induce toxicity in this experimental condition.

Data supporting the role of enzymes and polysaccharides during cassava postharvest physiological deterioration.

This data article is referred to the research article entitled The role of ascorbate peroxidase, guaiacol peroxidase, and polysaccharides in cassava (Manihot esculenta Crantz) roots under postharvest physiological deterioration by Uarrota et al. (2015). Food Chemistry 197, Part A, 737-746. The stress duo to PPD of cassava roots leads to the formation of ROS which are extremely harmful and accelerates cassava spoiling. To prevent or alleviate injuries from ROS, plants have evolved antioxidant systems that include non-enzymatic and enzymatic defence systems such as ascorbate peroxidase, guaiacol peroxidase and polysaccharides. In this data article can be found a dataset called "newdata", in RData format, with 60 observations and 06 variables. The first 02 variables (Samples and Cultivars) and the last 04, spectrophotometric data of ascorbate peroxidase, guaiacol peroxidase, tocopherol, total proteins and arcsined data of cassava PPD scoring. For further interpretation and analysis in R software, a report is also provided. Means of all variables and standard deviations are also provided in the Supplementary tables ("data.long3.RData, data.long4.RData and meansEnzymes.RData"), raw data of PPD scoring without transformation (PPDmeans.RData) and days of storage (days.RData) are also provided for data analysis reproducibility in R software.

The role of ascorbate peroxidase, guaiacol peroxidase, and polysaccharides in cassava (Manihot esculenta Crantz) roots under postharvest physiological deterioration.

This study aimed to investigate the role of ascorbate peroxidase (APX), guaiacol peroxidase (GPX), polysaccharides, and protein contents associated with the early events of postharvest physiological deterioration (PPD) in cassava roots. Increases in APX and GPX activity, as well as total protein contents occurred from 3 to 5 days of storage and were correlated with the delay of PPD. Cassava samples stained with Periodic Acid-Schiff (PAS) highlighted the presence of starch and cellulose. Degradation of starch granules during PPD was also detected. Slight metachromatic reaction with toluidine blue is indicative of increasing of acidic polysaccharides and may play an important role in PPD delay. Principal component analysis (PCA) classified samples according to their levels of enzymatic activity based on the decision tree model which showed GPX and total protein amounts to be correlated with PPD. The Oriental (ORI) cultivar was more susceptible to PPD.

Cephalothrix gen. nov. (Cyanobacteria): towards an intraspecific phylogenetic evaluation by multilocus analyses.

For more than a decade, the taxonomy of the Phormidiaceae has been problematic, since morphologically similar organisms represent phylogenetically distinct entities. Based on 16S rRNA gene sequence analyses, the polyphyletic genus Phormidium and other gas-vacuolated oscillatorioids appear scattered throughout the cyanobacterial tree of life. Recently, several studies have focused on understanding the oscillatorioid taxa at the generic level. At the specific level, few studies have characterized cyanobacterial strains using combined datasets (morphology, ultrastructure and molecular multilocus analyses). Using a multifaceted approach, we propose a new, well-defined genus, Cephalothrix gen. nov., by analysing seven filamentous strains that are morphologically 'intermediate' between gas-vacuolated taxa and Phormidium. Furthermore, we characterize two novel species: Cephalothrix komarekiana sp. nov. (strains CCIBt 3277, CCIBt 3279, CCIBt 3523, CCALA 155, SAG 75.79 and UTEX 1580) and Cephalothrix lacustris sp. nov. (strain CCIBt 3261). The generic name and specific epithets are proposed under the provisions of the International Code of Nomenclature for Algae, Fungi, and Plants.

The mechanism of action of ursolic acid as insulin secretagogue and insulinomimetic is mediated by cross-talk between calcium and kinases to regulate glucose balance.

BACKGROUND: The effect of in vivo treatment with ursolic acid (UA) on glycemia in hyperglycemic rats and its mechanism of action on muscle were studied. METHODS: The UA effects on glycemia, glycogen, LDH, calcium and on insulin levels were evaluated after glucose tolerance curve. The ß-cells were evaluated through the transmission electron microscopy. UA mechanism of action was studied on muscles through the glucose uptake with/without specific insulin signaling inhibitors. The nuclear effect of UA and the GLUT4 expression on muscle were studied using thymidine, GLUT4 immunocontent, immunofluorescence and RT-PCR. RESULTS: UA presented a potent antihyperglycemic effect, increased insulin vesicle translocation, insulin secretion and augmented glycogen content. Also, UA stimulates the glucose uptake through the involvement of the classical insulin signaling related to the GLUT4 translocation to the plasma membrane as well as the GLUT4 synthesis. These were characterized by increasing the GLUT4 mRNA expression, the activation of DNA transcription, the expression of GLUT4 and its presence at plasma membrane. Also, the modulation of calcium, phospholipase C, protein kinase C and PKCaM II is mandatory for the full stimulatory effect of UA on glucose uptake. UA did not change the serum LDH and serum calcium balance. CONCLUSIONS: The antihyperglycemic role of UA is mediated through insulin secretion and insulinomimetic effect on glucose uptake, synthesis and translocation of GLUT4 by a mechanism of cross-talk between calcium and protein kinases. GENERAL SIGNIFICANCE: UA is a potential anti-diabetic agent with pharmacological properties for insulin resistance and diabetes therapy.

Survival and ultrastructural features of peach palm (Bactris gasipaes, Kunth) somatic embryos submitted to cryopreservation through vitrification.

Bactris gasipaes (Arecaceae), also known as peach palm, was domesticated by Amazonian Indians and is cultivated for its fruit and heart-of-palm, a vegetable grown in the tree's inner core. Currently, the conservation of this species relies on in situ conditions and field gene banks. Complementary conservation strategies, such as those based on in vitro techniques, are indicated in such cases. To establish an appropriate cryopreservation protocol, this study aimed to evaluate the ultrastructural features of B. gasipaes embryogenic cultures submitted to vitrification and subsequent cryogenic temperatures. Accordingly, somatic embryo clusters were submitted to Plant Vitrification Solution 3 (PVS3). In general, cells submitted to PVS3 had viable cell characteristics associated with apparently many mitochondria, prominent nucleus, and preserved cell walls. Cells not incubated in PVS3 did not survive after the cryogenic process in liquid nitrogen. The best incubation time for the vitrification technique was 240 min, resulting in a survival rate of 37 %. In these cases, several features were indicative of quite active cell metabolism, including intact nuclei and preserved cell walls, an apparently many of mitochondria and lipid bodies, and the presence of many starch granules and condensed chromatin. Moreover, ultrastructure analysis revealed that overall cellular structures had been preserved after cryogenic treatment, thus validating the use of vitrification in conjunction with cryopreservation of peach palm elite genotypes, as well as wild genotypes, which carry a rich pool of genes that must be conserved.

The mechanism of adhesion and germination in the carpospores of Porphyra spiralis var. amplifolia (Rhodophyta, Bangiales).

Spore release is the primary means of dispersion employed by red algae, and it provides insight into the elements linking the stages of their life history. In most red algae, spores are released within a sheath-like envelope of mucilage, which is responsible for their primary attachment. However, few studies have characterized the polysaccharides involved in the adhesion of seaweed spores. Therefore, in this paper, the process of spore germination and adhesion in Porphyra spiralis var. amplifolia is described, as representative of the germination pattern of the Naccaria type. Using FITC-labeled lectins, we discovered high concentrations of α-D-mannose, α-D-glucose and ß-D-galactose in the mucilage. The germ tube reacted with RCA-FITC, indicating the presence ß-D-galactose, and the rhizoidal cells showed the presence of α-D-mannose, α-D-glucose and ß-D-galactose, indicating their importance to substrate adhesion. Using light and transmission electron microscopy, we also conducted an analysis of spore ultrastructure. We found that the differentiation of a vacuole in the spore is one of the most important processes marking the initial stage of germination. Thus, as the degree of vacuolation increases, whole cell contents move towards the germ tube, which undergoes several successive divisions forming the sporophytic phase. Therefore, we can conclude that germination in Porphyra spiralis var. amplifolia is characterized by (1) the fixation of carpospores in the substrate by sugars present in the mucilage and (2) the polarization of cell contents by the processes of vacuolization and germ tube formation.

Cytochemical characterization and ultrastructural organization in calluses of the agarophyte Gracilariopsis tenuifrons (Gracilariales, Rhodophyta).

The culture and physiology of red macroalgae calluses are well documented. To date, however, no report has either performed a cytochemical analysis or characterized the ultrastructural organization of calluses at different stages of development and under the effect of plant growth regulators. Therefore, to undertake such analyses, this work studied the red seaweed Gracilariopsis tenuifrons (Bird et Oliveira) Fredericq et Hommersand. Morphology studies suggested three types of calluses: a) terminal callus having an irregular amorphous shape and filamentous projections originating from the cortical region of the thallus; b) apical callus growing on apical branches and having an elongated semispherical shape; and c) intercalary callus developing along the intermediary region of the thallus and having the appearance of small declivities with irregular edges. The abundance of intercalary calluses over terminal and apical calluses is most likely a result of a major cortical surface that would support the cellular growth required to generate calluses. Callus development was initially observed as a matrix of cellular disorganization with filamentous projections; then, the cellular mass seemed to become more compact with spherical uncolored aspect. The presence of starch grains in the inner part of the explant could be explained by absorption from the culture medium and by proper biosynthesis during callus development. Cell wall reaction to staining suggested cellulose and agar composition with acidic polysaccharides. Results suggest that none of the three morphological types of calluses showed any significant differences on the basis of either cytochemistry or ultrastructural organization.

Ultrastructure of the siphonaceous green alga Halimeda cuneata, with emphasis on the cytoskeleton.

Cytoplasm streaming is a fundamental process for the transport of molecules and organelles in plant cells. In vegetative filaments of the coenocytic green alga, Halimeda cuneata Hering, the spatial organisation of microtubules in the cytoplasmic layer, was observed under transmission electron microscopy. A cross section of a cortical filament shows a tubular cell wall enclosing a peripheral layer of cytoplasm with numerous chloroplasts, amyloplasts, nuclei, mitochondria and microtubules surrounding a small central vacuole. Towards the thallus medulla the central vacuole enlarges considerably and the cytoplasm becomes gradually reduced to a thin parietal layer, the number of organelles is reduced and the quantity of microtubules increases. Therefore, most of the thallus volume is occupied by the huge central vacuole which extends throughout the coenocytic filaments. Microtubules run longitudinally, being about 0.05 microm from each other. Some microtubules were observed in close association to cell organelles.

Changes in ultrastructure and histochemistry of two red macroalgae strains of Kappaphycus alvarezii (Rhodophyta, Gigartinales), as a consequence of ultraviolet B radiation exposure.

Ultraviolet radiation (UVR) affects macroalgae in many important ways, including reduced growth rate, reduction of primary productivity and changes in cell biology and ultrastructure. Among red macroalgae, Kappaphycus alvarezii is of economic interest by its production of kappa carrageenan. Only a few reports have examined the changes in macroalgae ultrastructure and cell biology resulting from UVB radiation exposure. Therefore, we examined two strains of K. alvarezii (green and red) exposed to UVB for 3 h per day during 28 days and then processed them for histochemical and electron microscopy analysis. Reaction with Toluidine Blue showed an increase in the thickness of the cell wall and Periodic Acid-Schiff stain showed a decrease in the number of starch grains. UVBR also caused changes in the ultrastructure of cortical and subcortical cells, which included increased thickness of the cell wall and number of free ribosomes and plastoglobuli, reduced intracellular spaces, changes in the cell contour, and destruction of chloroplast internal organization. Based on these lines of evidence, it was evident by the ultrastructural changes observed that UVBR negatively affects intertidal macroalgae and, by extension, their economic viability.