Does attraction to frugivores or defense against pathogens shape fruit pulp composition?

Fruit traits evolve in response to an evolutionary triad between plants, seed dispersers, and antagonists that consume fruits but do not disperse seeds. The defense trade-off hypothesis predicts that the composition of nutrients and of secondary compounds in fruit pulp is shaped by a trade-off between defense against antagonists and attraction to seed dispersers. The removal rate model of this hypothesis predicts a negative relationship between nutrients and secondary compounds, whereas the toxin-titration model predicts a positive relationship. To test these alternative models, we evaluated whether the contents of nutrients and secondary compounds can be used to predict fruit removal by mutualists and pathogens in 14 bird-dispersed plants on a subtropical island in São Paulo state, southeastern Brazil. We selected eight to ten individuals of each species and prevented fruit removal by covering four branches with a net and left fruits on four other branches available to both, vertebrate fruit consumers and pathogens. The persistence of ripe fruits was drastically different among species for bagged and open fruits, and all fruit species persisted longer when protected against seed dispersers. We found that those fruits that are quickly removed by vertebrates are nutrient-rich, but although the attack rate of pathogens is also high, these fruits have low contents of quantitative defenses such as tannins and phenols. Thus, we suggest that the fruit removal rate by seed dispersers is the primary factor selecting the levels of fruit defense. Likewise, nutrient-poor fruits have low removal of seed dispersers and low probability of attack by pathogens. These species retain ripe fruits in an intact condition for a prolonged period because they are highly defended by secondary compounds, which reduce overall attractiveness. However, this strategy might be advantageous for plants that depend on rare or unreliable dispersers.     

Establishment of in vitro culture system for evaluating dentin–pulp complex regeneration with special reference to the differentiation capacity of BrdU label-retaining dental pulp cells

We have proposed the new hypothesis that dental pulp stem cells play crucial roles in the pulpal healing process following exogenous stimuli in cooperation with progenitors. This study aimed to establish an in vitro culture system for evaluating dentin–pulp complex regeneration with special reference to the differentiation capacity of slow-cycling long-term label-retaining cells (LRCs). Three intraperitoneal injections of BrdU were given to pregnant ICR mice to map LRCs in the mature tissues of born animals. The upper bilateral first molars of 3-week-old mice were extracted and divided into two pieces and cultured for 0, 1, 3, 5 and 7 days using the Trowel’s method. We succeeded in establishing an in vitro culture system for evaluating dentin–pulp complex regeneration, where most odontoblasts were occasionally degenerated and lost nestin immunoreactivity because of the separation of cell bodies from cellular processes in the dentin matrix by the beginning of in vitro culture. Numerous dense LRCs mainly resided in the center of the dental pulp associating with blood vessels throughout the experimental periods. On postoperative days 1–3, the periphery of the pulp tissue including the odontoblast layer showed degenerative features. By Day 7, nestin-positive odontoblast-like cells were arranged along the pulp–dentin border and dense LRCs were committed in the odontoblast-like cells. These results suggest that dense LRCs in the center of the dental pulp associating with blood vessels were supposed to be dental pulp stem/progenitor cells possessing regenerative capacity for forming newly differentiated odontoblast-like cells.     

Properties of Streptomyces sp. endo-β-xylanases in relation to their applicability in kraft pulp bleaching

A screening of a collection of Streptomyces sp. strains has shown that Streptomyces achromogenes 5028 (S1), Streptomyces longisporus ruber 4–167 (S2) and Streptomyces sp. 8812 (S3) degraded efficiently beechwood xylan. The -xylanase activities present in the culture filtrate of the strains were purified to electrophoretic homogeneity and found to be typical non-debranching endo--xylanases (1,4--D-xylan xylanohydrolases: E.C. 3.2.1.8) with respective molecular weights of 25,000 (S1), 45,000 (S2) and 22,000 (S3). The enzymes were characterized with respect to their temperature–pH relationship and kinetic profile. Immunological experiments suggested that the enzyme produced by S1 belonged to family 11 of glycanases and the S3 enzyme to family 10. The three xylanases adsorbed onto crystalline cellulose but were catalytically inert towards this material, indicating a possible application of these enzymes in biobleaching processes. With respect to its effect on and brightness values in a DEDED bleaching sequence, the xylanase produced by the S1 strain appeared as comparable to a Trichoderma longibrachiatum commercial enzyme preparation (Novozym 431). Streptomyces sp. xylanases may find applications in elemental-chlorine-free bleaching procedures.     

New polyoxometalate–laccase integrated system for kraft pulp delignification

New polyoxometalate–laccase integrated system (PLIDS) employing polyoxometalate [SiW₁₁V^VO₄₀]⁵⁻ and laccase of Trametes versicolor for the continuous delignification of eucalypt kraft pulp has been developed. Pulp was delignified in a batch reactor containing catalytic amounts of [SiW₁₁V^VO₄₀]⁵⁻ at about 90 °C under atmospheric pressure. Re-oxidation of reduced polyoxometalate (POM) with laccase was carried out at 45 °C in a separate aerated bioreactor coupled with an ultrafiltration tubular ceramic membrane. This allowed the separation of laccase from re-oxidized POM, which was supplied in turn continuously to the delignification reactor.Proposed PLIDS allowed sustainable pulp delignification with minimal degradation of polysaccharides. The implementation of PLIDS, instead the fist chlorine dioxide stage (D) in conventional DEDED bleaching sequence, showed almost 60% of chlorine dioxide savings with strength properties of the bleached pulp (90% ISO) similar to those obtained after the conventional bleaching.     

Responses of neurons of different hypothalamic structures to stimulation of tooth pulp and Aß afferents in the cat sciatic nerve

The response of neurons of different hypothalamic structures to stimulation of painful tooth pulp afferents and painless sciatic nerve Aß afferents was investigated during acute experiments on cats. It was found that 80.7%, 81.5%, and 71.4% of neurons of the posterior, tuberal, and anterior hypothalamus respectively, responded to stimulation of the tooth pulp. Shortest latency of response was recorded in the posterolateral hypothalamus. Latency of response was shorter in the lateral than in the medial structures throughout the hypothalamus. A distinct prevalence of excitatory response was found in neurons of the posterior area and an almost equal proportion of excitatory and inhibitory response in neurons of the tuberal and anterior hypothalamus. A high degree of convergence between noxious and nonnoxious somatic afferents were discovered in hypothalamic neurons: 85.8% of those studied responded to stimulation of the sciatic nerve Aß afferents. The comparable unidirectional response pattern of hypothalamic neurons to stimulation of tooth pump painful afferents and painless sciatic nerve Aß fibers point to the nonspecific nature of the response observed in the mainstream population of multisensory hypothalamic neurons. A small population of unimodal nociceptive neurons (14.2%) was found in the hypothalamus. Nociceptive responses of anterior hypothalamic neurons were distinguished by their long refractory phase, lasting 200–500 msec, and their low rate of reproduction during rhythmic stimulation of tooth pulp (1.5–2 Hz). Neuronal organization of the nociceptive hypothalamic afferent system is discussed together with the role of convergent and specific "nociceptive" neurons in the shaping of thalamic regulatory functions.L. A. Orbeli Institute of Physiology, Academy of Sciences of the Armenian SSR, Erevan. Translated from Neirofiziologiya, Vol. 18, No. 2, pp. 171–180, March–April, 1986.     

Biotechnological management of coffee pulp — isolation,screening, characterization,selection of caffeine-degrading fungi and natural microflora present in coffee pulp and husk

A total of 272 strains of filamentous fungi were isolated from soil, leaves of coffee plants and coffee cherries collected in coffee-growing areas of Mexico on three semi-synthetic culture media containing coffee extract, coffee extract with sucrose and coffee pulp extract. The isolated strains were purified by conventional techniques and identified by microscopic examination. Strains were selected on the basis of their caffeine-degrading ability in well-defined liquid medium containing caffeine. Most of the isolated microorganisms belong to Aspergillus, Penicillium, Trichoderma, Fusarium, and Humicola genera. Five strains belonging to Aspergillus species and two strains belonging to Penicillium species had the ability to degrade almost 100% of the caffeine in liquid medium. A comparative study on the evaluation of natural microflora present in coffee pulp and coffee husk revealed the presence of a wide variety of microorganisms. The percentage distribution of fungi, bacteria and yeast was almost similar in all the samples, except in coffee husk where the fungal population was slightly higher than in the other two samples. The yeast population was predominant when the coffee pulp was lyophilized immediately after pulping. However, there was a wide diversity in the microbial population with respect to selective media containing functional nutritional groups like cellulose, starch and pectin.     

Tissue engineering: Dentin – pulp complex regeneration approaches (A review)

Dental pulp is a highly specialized tissue that preserves teeth. It is important to maintain the capabilities of dental pulp before a pulpectomy by creating a local restoration of the dentin-pulp complex from residual dental pulp. The articles identified were selected by two reviewers based on entry and exit criteria. All relevant articles indexed in PubMed, Springer, Science Direct, and Scopus with no limitations from 1961 to 2016 were searched. Factors investigated in the selected articles included the following key words: Dentin-Pulp Complex, Regeneration, Tissue Engineering, Scaffold, Stem Cell, and Growth Factors. Of the 233 abstracts retrieved, the papers which were selected had evaluated the clinical aspects of the application of dentin-pulp regeneration. Generally, this study has introduced a new approach to provoke the regeneration of the dentin-pulp complex after a pulpectomy, so that exogenous growth factors and the scaffold are able to induce cells and blood vessels from the residual dental pulp in the tooth root canal. This study further presents a new strategy for local regeneration therapy of the dentin-pulp complex. This review summarizes the current knowledge of the potential beneficial effects derived from the interaction of dental materials with the dentin-pulp complex as well as potential future developments in this exciting field.     

Bioprospecting of thermo- and osmo-tolerant fungi from mango pulp–peel compost for bioethanol production

The persistent edaphic stress on microbial succession due to dynamic changes during composting was explored for selection of multi-stress tolerant microbe(s) desirable for ethanol production. A total of 23 strains were isolated from mango compost using four successive enrichments in YP broth (g l^?1): glucose, 100; 150; 250 with ethanol (40) and cycloheximide (0.4) at 40 °C, pH 6.0. Based on multi-gene ribotyping, 14 yeasts (61 %) of Saccharomycetaceae, 2 filamentous fungi (8.6 %) and 7 bacteria (30.4 %) were obtained. Phenetic and phylogenetic analysis of the 14 yeasts revealed 64.3 % tolerant to 500 g l^?1 glucose, growth at 45 °C and resemblance to Candida sp. (14.3 %), Kluyveromyces marxianus (35.7 %), Pichia kudriavzevii (21.4 %) and Saccharomyces cerevisiae (28.6 %). Assessment of the 14 yeasts in glucose fermentation medium (pH 4.5 at 40 °C) showed ethanol productivity of ≥92 % by 12 yeasts with theoretical yields of 90–97 %. Fermentation of molasses (150 g l^?1 glucose equivalent) by P. kudriavzevii D1C at 40 °C resulted in 73.70 ± 0.02 g l^?1 ethanol and productivity of 4.91 ± 0.01 g l^?1 h^?1. Assessment of P. kudriavzevii D1C revealed multi-stress tolerance towards 5-hydroxymethyl furfural, ethanol (20 %, v/v), high gravity and H₂O₂ (0.3 M) indicating suitability for ethanol production using high gravity molasses and pre-treated lignocellulosic biomass fermentation.     

Constitutive activation of β-catenin in odontoblasts induces aberrant pulp calcification in mouse incisors

Journal of Molecular Histology - During dentin formation, odontoblast polarization ensures that odontoblasts directionally secrete dentin matrix protein, leading to tubular dentin formation;...     

Pollution control in pulp and paper industrial effluents using integrated chemical–biological treatment sequences

The main objective of the present study was to improve the quality of pulp and paper industrial wastewater of two local mills RAKTA and El-Ahlia, Alexandria, Egypt, and to bring their pollutant contents to safe discharge levels. Quality improvement was carried out using integrated chemical and biological treatment approaches after their optimization. Chemical treatment (alum, lime, and ferric chloride) was followed by oxidation using hydrogen peroxide and finally biological treatment using activated sludge (90 min for RAKTA and 60 min for El-Ahlia effluents). Chemical coagulation produced low-quality effluents, while pH adjustment during coagulation treatment did not enhance the quality of the effluents. Maximum removal of the tested pollutants was achieved using the integrated treatment and the pollutants recorded residual concentrations (RCs) of 34.67, 17.33, 0.13, and 0.43 mg/l and 15.0, 11.0, 0.0, and 0.13 mg/l for chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), tannin and lignin, and silica in RAKTA and El-Ahlia effluents, respectively, all of which were below their maximum permissible limits (MPLs) for the safe discharge into water courses. Specific oxygen uptake rate (SOUR) and sludge volume index (SVI) values reflect good conditions and healthy activated sludge. Based on the previous results, optimized conditions were applied as bench scale on the raw effluents of RAKTA and El-Ahlia via the batch chemical and the biological treatment sequences proposed. For RAKTA effluents, the sequence was as follows: (1) coagulation with 375 mg/l FeCl₃, (2) oxidation with 50 mg/l hydrogen peroxide, and (3) biological treatment using activated sludge with 2,000 mg/l initial concentration and 90 min hydraulic retention time (HRT), while for El-Ahlia raw effluents, the sequence was (1) coagulation with 250 mg/l FeCl₃, (2) oxidation with 45 mg/l hydrogen peroxide, and (3) biological treatment using activated sludge with 2,000 mg/l initial concentration and 60 min HRT. In conclusion, results confirmed that the application of the proposed sequential treatments removed almost all COD, BOD₅, high molecular weight compounds, and silica from RAKTA and El-Ahlia influents and produced high-quality effluents, thus achieving the main objective of this study.     

Main lipophilic extractives in different paper pulp types can be removed using the laccase–mediator system

Lipophilic extractives in wood and other lignocellulosic materials exert a negative impact in pulp and paper manufacturing causing the so-called pitch problems. In this work, the appropriateness of an enzymatic treatment using the laccase–mediator system for pitch biocontrol is evaluated. With this purpose, three pulp types representative for different raw materials and pulping processes—eucalypt kraft pulping, spruce thermomechanical pulping, and flax soda-anthraquinone pulping—were treated with a high-redox-potential laccase from the basidiomycete Pycnoporus cinnabarinus in the presence of 1-hydroxybenzotriazole as a redox mediator. The gas chromatography and gas chromatography/mass spectrometry analyses of the lipophilic extractives from the enzymatically treated pulps revealed that the laccase–mediator treatment completely or greatly removed most of the pitch-causing lipophilic compounds present in the different pulps including: (1) free and conjugated sitosterol in eucalypt paper pulp; (2) resin acids, sterol esters, and triglycerides in spruce pulp; and (3) sterols and fatty alcohols in the flax pulp. Different amounts of free and conjugated 7-oxosterols were found as intermediate products in the oxidation of pulp sterols. Therefore, the laccase–mediator treatment is reported as an efficient method for removing pitch-causing lipophilic compounds from paper pulps obtained from hardwood, softwood, and nonwoody plants.     

Matrix and TGF-β-related gene expression during human dental pulp stem cell (DPSC) mineralization

We have recently reported the induction of dental pulp stem cells (DPSCs) into dentin-secreting odontoblast-like cells after stimulation by isolated dentin matrix components, thus mimicking the nature of tissue regeneration seen after tooth disease and injury. After confluency, the cells were further cultured for 21 d in the 10% fetal bovine serum (FBS) Dulbecco’s modified Eagle’s medium (DMEM) (control), and in this medium, with the addition of dentin extract (DE) and the mineralization supplement (MS) of ascorbic acid and β-glycerophosphate (treatment). To identify genes associated with this process, specimens were analyzed with a HG-U133A human gene chip and Arrayassist software. A total of 425 genes, among them 21 matrix and eight TGF-β-related genes, were either up- or downregulated in the experimental group in which the cells showed odontoblast-like differentiation and mineralization. Expression of selected genes was further confirmed by real-time polymerase chain reaction (PCR) analysis. Of the extracellular matrix (ECM)-related genes, two types of collagen genes were upregulated and seven others downregulated. Other ECM-related genes, for example fibulin-1, tenascin C, and particularly thrombospondin 1, were upregulated, and fibulin-2 was downregulated. Most noticeably, the matrix metalloproteinase 1 was induced by the treatment. In the TGF-β superfamily, upregulation of the type II receptor, endoglin, and growth/differentiation factor 5 was coordinated with the downregulation of activin A, TGF-β2, and TGF-β1 itself. This study identifies the matrix and TGF-β-related gene profiles during the DPSC cell mineralization in which several genes are reported for the first time to be associated with this process, thus greatly expanding our molecular knowledge of the induced disease repair process.     

How to regulate a gene: to repress or to activate?

Gene-expression responses to an input can depend on growth conditions; in this issue, Sasson et al. (2012) show that this dependence is lower when the input results in a high degree of promoter occupancy.     

Kinetics of Thermoascus aurantiacus solid-state fermentation on sugar-beet pulp – polysaccharide alteration and production of related enzymatic activities

 The fungal solubilization of cell wall components of sugar-beet pulp, during solid-state fermentation of Thermoascus aurantiacus, is reported here. The extracellular fungal enzyme activities related to the substrate degradation were also studied. In 120 h, more than 60% of the main sugar-beet pulp polysaccharides, i.e. pectins, arabinose- and glucose-containing polysaccharides, were rapidly brought into solution by the fungus. The slow accumulation of monosaccharides compared to the fast degradation of the polysaccharides suggested that most of the released sugars were consumed by the fungus. The analysis of the enzymes present in the water extracts of the solid-state cultures proved that the fungus was able to synthesize a complete enzymatic system required for the hydrolysis of the main sugar-beet pulp polysaccharides. The highest enzyme activities measured were β-glucosidase and α-L-arabinofuranosidase. Received: 22 September 1995/Received revision: 15 January 1996/Accepted: 22 January 1996     

Did fleshy fruit pulp evolve as a defence against seed loss rather than as a dispersal mechanism?

Relatively few studies have examined the evolution of the mutualism between endozoochorous plants and seed dispersers. Most seed dispersal studies are ecological and examine the role of fruit pulp in promoting seed dispersal. This interaction is often assumed to have originated due to selection stemming from seed dispersers. Here I suggest a "defence scenario" wherein fleshy fruits originated as mechanisms to defend seeds and secondarily became structures to promote seed dispersal. I suggest that frugivory followed from herbivores that specialized on consuming seed defensive tissues and that enhanced seed dispersal was initially a consequence of seed defence. The proposed defence scenario is not posited as an explanation for the sequence that led to all modern frugivores. However, it is suggested that seed predation was the initial source of selection that led to fleshy fruits; the necessary precursor to frugivory. Support is described from the fossil record and from modern structures and interactions. Testable predictions are made in hope that greater interest will be focused on the defensive role of fleshy fruit pulp both in modern interactions and historically.     

Recombinant expression,characterization, and pulp prebleaching property of a Phanerochaete chrysosporium endo-β-1,4-mannanase

A Phanerochaete chrysosporium cDNA predicted to encode endo-1,4-β-d-mannanase, man5D, was cloned and expressed in Aspergillus niger. The coding region of the gene man5D was predicted to contain, in order from the N-terminal: a secretory signal peptide, cellulose-binding domain, linker region, and glycosyl hydrolase family 5 catalytic site. The enzyme was purified from culture filtrate of A. niger transformants that carried the recombinant man5D. Recombinant Man5D had an apparent molecular size of about 65 kDa by SDS-PAGE, and optimal activity at pH 4.0–6.0 and 60 °C. It was stable from pH 4.0 to 8.0 and up to 60 °C. The enzyme showed affinity for Avicel cellulose, suggesting that the predicted cellulose-binding domain is biologically functional. The specific activities of Man5D on mannan, galactomannan, and glucomannan at pH 5 and 60 °C ranged from 160 to 460 μmol/(min mg), with apparent K_m values from 0.54 to 2.3 mg/mL. Product analysis results indicated that Man5D catalyzes endo-cleavage, and appears to have substantial transglycosylase activity. When used to treat softwood kraft pulp, Man5D hydrolyzed mainly glucomannan and exhibited a positive effect as a prebleaching agent. Compared to a commercial prebleaching with xylanase, the prebleaching effect of Man5D was weaker but with reduced loss of fibre yield as determined by the release of solubilized sugars.     

Disgust sensitivity relates to affective responses to – but not ability to detect – olfactory cues to pathogens

Hundreds of studies have assessed variation in the degree to which people experience disgust toward substances associated with pathogens, but little is known about the mechanistic sources of this variation. The current investigation uses olfactory perception and threshold methods to test whether it is apparent at the cue-detection level, at the cue-interpretation level, or both. It further tests whether relations between disgust sensitivity and olfactory perception are specific to odors associated with pathogens. Two studies (N's = 119 and 160) of individuals sampled from a Dutch university each revealed that pathogen disgust sensitivity relates to valence perceptions of odors found in pathogen sources, but not to valence perceptions of odors not associated with pathogens, nor to intensity perceptions of odors of either type. Study 2, which also assessed olfactory thresholds via a three-alternative forced-choice staircase method, did not reveal a relation between pathogen disgust sensitivity and the ability to detect an odor associated with pathogens, nor an odor not associated with pathogens. In total, results are consistent with the idea that pathogen disgust sensitivity relates to how olfactory pathogen cues are interpreted after detection, but not necessarily to the ability to detect such cues.     

Micromanipulation of culture niche permits long-term expansion of dental pulp stem cells—an economic and commercial angle

Stem cells isolated from dental pulp possess the capacity for self-renewal and the potential for multi-lineage differentiation. However, dental pulp stem cells have different characteristics in terms of their culture conditions. The success of stem cells culture is governed by its micro-environmental niche. Therefore, we studied the effects of culture niche on long-term expansion of dental pulp stem cells in terms of cell morphology, growth kinetics, senescence pattern, cell surface marker expression differentiation capacity, and seeding plating density of dental pulp stem cells in four different, widely used media composition Among the various basal media tested, α-minimum essential media and knock out-minimum essential media supplemented with 10% fetal bovine serum were found to be the most optimal media composition in preserving the phenotypic characteristics and differentiation potential for prolonged periods as compared with DMEM-F12 and DMEM-LG. Plating density has been shown to affect overall yield. As a conclusion, the adoption of an appropriate culture system significantly improved cell yield, thus enabling the attainment of sufficient yields for therapeutic applications economizing in terms of cost of production and minimizing seeding cell density for maximum yield.