Epigenetic repressor-like genes are differentially regulated during grapevine (Vitis vinifera L.) development

Grapevine sexual reproduction involves a seasonal separation between inflorescence primordia (flowering induction) and flower development. We hypothesized that a repression mechanism implicating epigenetic changes could play a role in the seasonal separation of these two developmental processes in grapevine. Therefore, the expression of five grapevine genes with homology to the Arabidopsis epigenetic repressor genes FERTILIZATION INDEPENDENT ENDOSPERM (FIE), EMBRYONIC FLOWER 2 (EMF2), CURLY LEAF (CLF), MULTICOPY SUPPRESSOR OF IRA 1 (MSI1) and SWINGER (SWN) was analyzed during the development of buds and vegetative and reproductive organs. During bud development, the putative grapevine epigenetic repressor genes VvCLF, VvEMF2, VvMSI1, VvSWN and VvFIE are mainly expressed in latent buds at the flowering induction period, but also detected during bud burst and inflorescence/flower development. The overlapping expression patterns of grapevine PcG-like genes in buds suggest that chromatin remodeling mechanisms could be operating during grapevine bud development for controlling processes such as seasonal flowering, dormancy and bud burst. Furthermore, the expression of grapevine PcG-like genes was also detected in fruits and vegetative organs, suggesting that epigenetic changes could be at the basis of the regulation of various proliferation–differentiation cell transitions that occur during grapevine development.     

Macleya cordata and Prunella vulgaris in oral hygiene products - their efficacy in the control of gingivitis

A double-blind, placebo-controlled clinical trial was performed to investigate the effectiveness of a herbal-based dentifrice in the control of gingivitis. Forty volunteers completed the 84-day study. All subjects were balanced for parameters measured - plaque index (PI), community periodontal index of treatment needs (CPITN) and papillary bleeding index (PBI). The dentifrice was effective in reducing symptoms of gingivitis as evaluated by the CPITN and PBI indexes.     

Flow cell hydrodynamics and their effects on E. coli biofilm formation under different nutrient conditions and turbulent flow

Biofilm formation is a major factor in the growth and spread of both desirable and undesirable bacteria as well as in fouling and corrosion. In order to simulate biofilm formation in industrial settings a flow cell system coupled to a recirculating tank was used to study the effect of a high (550 mg glucose l?1) and a low (150 mg glucose l?1) nutrient concentration on the relative growth of planktonic and attached biofilm cells of Escherichia coli JM109(DE3). Biofilms were obtained under turbulent flow (a Reynolds number of 6000) and the hydrodynamic conditions of the flow cell were simulated by using computational fluid dynamics. Under these conditions, the flow cell was subjected to wall shear stresses of 0.6 Pa and an average flow velocity of 0.4 m s?1 was reached. The system was validated by studying flow development on the flow cell and the applicability of chemostat model assumptions. Full development of the flow was assessed by analysis of velocity profiles and by monitoring the maximum and average wall shear stresses. The validity of the chemostat model assumptions was performed through residence time analysis and identification of biofilm forming areas. These latter results were obtained through wall shear stress analysis of the system and also by assessment of the free energy of interaction between E. coli and the surfaces. The results show that when the system was fed with a high nutrient concentration, planktonic cell growth was favored. Additionally, the results confirm that biofilms adapt their architecture in order to cope with the hydrodynamic conditions and nutrient availability. These results suggest that until a certain thickness was reached nutrient availability dictated biofilm architecture but when that critical thickness was exceeded mechanical resistance to shear stress (ie biofilm cohesion) became more important.     

Thermodynamic properties and characterization of proteoliposomes rich in microdomains carrying alkaline phosphatase

Tissue-nonspecific alkaline phosphatase (TNAP) is associated to the plasma membrane via a GPI-anchor and plays a key role in the biomineralization process. In plasma membranes, most GPI-anchored proteins are associated with "lipid rafts", ordered microdomains enriched in sphingolipids, glycosphingolipids and cholesterol. In order to better understand the role of lipids present in rafts and their interactions with GPI-anchored proteins, the insertion of TNAP into different lipid raft models was studied using dipalmitoylphosphatidylcholine (DPPC), cholesterol (Chol), sphingomyelin (SM) and ganglioside (GM1). Thus, the membrane models studied were binary systems (9:1 molar ratio) containing DPPC:Chol, DPPC:SM and DPPC:GM1, ternary systems (8:1:1 molar ratio) containing DPPC:Chol:SM, DPPC:Chol:GM1 and DPPC:SM:GM1 and finally, a quaternary system (7:1:1:1 molar ratio) containing DPPC:Chol:SM:GM1. Calorimetry analysis of the liposomes and proteoliposomes indicate that lateral phase segregation could be noted only in the presence of cholesterol, with the formation of cholesterol-rich microdomains centered above Tc=41.5°C. The presence of GM1 and SM into DPPC-liposomes influenced mainly ΔH and Δt(1/2) values. The gradual increase in the complexity of the systems decreased the activity of the enzyme incorporated. The presence of the enzyme also fluidifies the systems, as seen by the intense reduction in ?H values, but do not alter Tc values significantly. Therefore, the study of different microdomains and its biophysical characterization may contribute to the knowledge of the interactions between the lipids present in MVs and its interactions with TNAP.     

Diplospory and obligate apomixis in Miconia albicans (Miconieae, Melastomataceae) and an embryological comparison with its sexual congener M. chamissois

Apomixis, or asexual reproduction through seeds, has been reported for species of the tribe Miconieae, Melastomataceae, but details of the process have yet to be described. We analyzed and compared sporogenesis and gametogenesis in the apomictic Miconia albicans and the sexual M. chamissois. The results point to some differences between species, which were related to the apomictic process. In M. albicans microsporogenesis, problems during meiosis and degeneration of its products led to total pollen sterility, while M. chamissois presented normal bicellular pollen grains in the mature anther. The absence or abnormality of meiosis in M. albicans megasporogenesis led to the formation of an unreduced embryo sac and also to egg cell parthenogenesis, which gave rise to the apomictic embryo. Embryo and endosperm development were autonomous, resulting in seeds and fruits independent of pollination and fertilization. Thus, in this species, apomixis can be classified as diplosporic and obligate. In contrast, meiosis was as expected in the sexual M. chamissois, and led to the development of a reduced embryo sac. Despite the divergent pathways, many embryological characteristics were similar between the studied species and other Melastomataceae and they seem to be conservative character states for the family.     

Shell Beds as paleoecological puzzles: A case study from the Upper Permian of the Paraná Basin, Brazil

Summary Microstratigraphic, sedimentological, and taphonomic features of the Ferraz Shell Bed, from the Upper Permian (Kazanian-Tatarian?) Corumbataí Formation of Rio Claro Region (the Paraná Basin, Brazil), indicate that the bed consists of four distinct microstratigraphic units. They include, from bottom to top, a lag concentration (Unit 1), a partly reworked storm deposit (Unit 2), a rapidly deposited sandstone unit with three thin horizons recording episodes of reworking (Unit 3), and a shell-rich horizon generated by reworking/winnowing that was subsequently buried by storm-induced obrution deposit (Unit 4). The bioclasts of the Ferraz Shell Bed represent exclusively bivalve mollusks.Pinzonellaillusa andTerraia aequilateralis are the dominant species. Taphonomic analysis indicates that mollusks are heavily time-averaged (except for some parts of Unit 3). Moreover, different species are time-averaged to a different degree (disharmonious time-averaging). The units differ statistically from one another in their taxonomic and ecological composition, in their taphonomic pattern, and in the size-frequency distributions of the two most common species. Other Permian shell beds of the Paraná Basin are simílar to the Ferraz Shell Bed in their faunal composition (they typically contain similar sets of 5 to 10 bivalve species) and in their taphonomic, sedimentologic, and microstratigraphic characteristics. However, rare shell beds that include 2–3 species only and are dominated by articulated shells preserved in life position also occur. Diversity levels in the Permian benthic associations of the Paraná Basin were very low, with the point diversity of 2–3 species and with the within-habitat and basin-wide (alpha and gamma) diversities of 10 species, at most. The Paraná Basin benthic communities may have thus been analogous to low-diversity bivalve-dominated associations of the present-day Baltic Sea. The ‘Ferraz-type’ shell beds of the Paraná Basin represent genetically complex and highly heterogeneous sources of paleontological data. They are cumulative records of spectra of benthic ecosystems time-averaged over long periods of time (10²–10⁴ years judging from actualistic research). Detailed biostratinomic reconstructions of shell beds can not only offer useful insights into their depositional histories, but may also allow paleoecologists to optimize their sampling designs, and consequently, refine paleoecological and paleoenvironmental interpretations.     

Isolation of complement-fragment-iC3b-binding proteins by affinity chromatography. The identification of p150,95 as an iC3b-binding protein.

The proteins from labelled human spleen membranes and polymorphonuclear leucocytes which bind to the iC3b fragment of complement component C3 were prepared by iC3b-Sepharose chromatography in the presence of bivalent cations. Complement receptor type 3(CR3) was eluted from iC3b-Sepharose by removal of bivalent cations. Complement receptors type 1 and 2 (present in spleen but not in polymorphonuclear leucocytes) were sequentially eluted by an NaCl gradient. An additional protein of Mr 135 000 was eluted from iC3b-Sepharose under the same conditions as those used to elute CR3. Preabsorption of the starting material on an anti-(CR3 beta-subunit) antibody column before iC3b-Sepharose chromatography removed the alpha- and beta-chains of CR3 and the 135 000-Mr protein. Preabsorption with iC3b-Sepharose before the anti-(CR3 beta-subunit) antibody column showed that iC3b binds CR3 and p150,95, the smallest member of the group of three homologous proteins that share the same beta-subunit.     

Dynamics of G6PD activity in patients receiving weekly primaquine for therapy of Plasmodium vivax malaria

BackgroundAcute Plasmodium vivax malaria is associated with haemolysis, bone marrow suppression, reticulocytopenia, and post-treatment reticulocytosis leading to haemoglobin recovery. Little is known how malaria affects glucose-6-phosphate dehydrogenase (G6PD) activity and whether changes in activity when patients present may lead qualitative tests, like the fluorescent spot test (FST), to misdiagnose G6PD deficient (G6PDd) patients as G6PD normal (G6PDn). Giving primaquine or tafenoquine to such patients could result in severe haemolysis.MethodsWe investigated the G6PD genotype, G6PD enzyme activity over time and the baseline FST phenotype in Cambodians with acute P. vivax malaria treated with 3-day dihydroartemisinin piperaquine and weekly primaquine, 0·75 mg/kg x8 doses.ResultsOf 75 recruited patients (males 63), aged 5–63 years (median 24), 15 were G6PDd males (14 Viangchan, 1 Canton), 3 were G6PD Viangchan heterozygous females, and 57 were G6PDn; 6 patients had α/β-thalassaemia and 26 had HbE.Median (range) Day0 G6PD activities were 0·85 U/g Hb (0·10–1·36) and 11·4 U/g Hb (6·67–16·78) in G6PDd and G6PDn patients, respectively, rising significantly to 1·45 (0·36–5·54, p<0.01) and 12·0 (8·1–17·4, p = 0.04) U/g Hb on Day7, then falling to ~Day0 values by Day56. Day0 G6PD activity did not correlate (p = 0.28) with the Day0 reticulocyte counts but both correlated over time. The FST diagnosed correctly 17/18 G6PDd patients, misclassifying one heterozygous female as G6PDn.ConclusionsIn Cambodia, acute P. vivax malaria did not elevate G6PD activities in our small sample of G6PDd patients to levels that would result in a false normal qualitative test. Low G6PDd enzyme activity at disease presentation increases upon parasite clearance, parallel to reticulocytosis. More work is needed in G6PDd heterozygous females to ascertain the effect of P. vivax on their G6PD activities.Trial registrationThe trial was registered (ACTRN12613000003774) with the Australia New Zealand Clinical trials (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=363399&isReview=true).     

Linear and nonlinear stiffness and friction in biological rhythmic movements

Biological rhythmic movements can be viewed as instances of self-sustained oscillators. Auto-oscillatory phenomena must involve a nonlinear friction function, and usually involve a nonlinear elastic function. With respect to rhythmic movements, the question is: What kinds of nonlinear friction and elastic functions are involved? The nonlinear friction functions of the kind identified by Rayleigh (involving terms such as $\dot \theta ^3 $ ) and van der Pol (involving terms such as $\theta ^2 \dot \theta $ ), and the nonlinear elastic functions identified by Duffing (involving terms such as $\theta ^3 $ ), constitute elementary nonlinear components for the assembling of self-sustained oscillators. Recently, additional elementary nonlinear friction and stiffness functions expressed, respectively, through terms such as $\theta ^2 \dot \theta ^3 $ and $\theta \dot \theta ^2 $ , and a methodology for evaluating the contribution of the elementary components to any given cyclic activity have been identified. The methodology uses a quantification of the continuous deviation of oscillatory motion from ideal (harmonic) motion. Multiple regression of this quantity on the elementary linear and nonlinear terms reveals the individual contribution of each term to the oscillator's non-harmonic behavior. In the present article the methodology was applied to the data from three experiments in which human subjects produced pendular rhythmic movements under manipulations of rotational inertia (experiment 1), rotational inertia and frequency (experiment 2), and rotational inertia and amplitude (experiment 3). The analysis revealed that the pendular oscillators assembled in the three experiments were compositionally rich, braiding linear and nonlinear friction and elastic functions in a manner that depended on the nature of the task.