Flesh Tissue Research Articles

Differential effect of ethylene supplementation and inhibition on abscisic acid metabolism of potato (Solanum tuberosum L.) tubers during storage

Ethylene is used as a commercial potato sprout suppressant, but the role of ethylene in potato dormancy is unclear and contradictory. Two potato cultivars ‘Estima’ and ‘Marfona’ were treated with air or continuous ethylene (10μLL−1), transferred from air to ethylene or vice versa at first indication of sprouting (10% peeping of the control tubers), over three seasons. The ethylene binding inhibitor, 1-methylcyclopropene, was applied (1μLL−1 for 24h) either at harvest and/or at first indication of sprouting. Tubers were stored at 6°C for 30 weeks and assessed for sprout length and number, and non-structural carbohydrate content. Abscisic acid (ABA) metabolism in tubers throughout storage was monitored. Ethylene applied from harvest or the first indication of sprouting reduced sprout growth significantly for both cultivars while ethylene induced sugar accumulation was prevented by 1-MCP application prior to ethylene storage. Multiple applications of 1-MCP showed no additional benefit to ethylene induced sugar accumulation. A rise in ABA content in flesh tissue was observed in response to ethylene application while 1-MCP blocked the ethylene induced rise in ABA caused by exogenous and endogenous ethylene. The increase in ABA caused by ethylene may delay dormancy break yet 1-MCP blocked this rise in ABA with no apparent effect on sprout behaviour. Sucrose is a prerequisite signalling molecule for hormonal dormancy control. 1-MCP reduced the ethylene induced rise in sucrose content therefore although 1-MCP reduced ABA, the reduction in sucrose content may still have delayed sprout initiation. However, the level of sucrose in the 1-MCP treated tubers did not decrease below that of the control. Taken together, ABA and sucrose may play a role in the sprout suppressing ability of exogenously applied ethylene, but it is clear that other factors are involved.

Analysis of Light Transport Features in Stone Fruits Using Monte Carlo Simulation

The propagation of light in stone fruit tissue was modeled using the Monte Carlo (MC) method. Peaches were used as the representative model of stone fruits. The effects of the fruit core and the skin on light transport features in the peaches were assessed. It is suggested that the skin, flesh and core should be separately considered with different parameters to accurately simulate light propagation in intact stone fruit. The detection efficiency was evaluated by the percentage of effective photons and the detection sensitivity of the flesh tissue. The fruit skin decreases the detection efficiency, especially in the region close to the incident point. The choices of the source-detector distance, detection angle and source intensity were discussed. Accurate MC simulations may result in better insight into light propagation in stone fruit and aid in achieving the optimal fruit quality inspection without extensive experimental measurements.

Changes in minimally processed apple tissue with storage time and temperature: mechanical–acoustic analysis and rheological investigation

Texture and mesostructure of packaged fresh-cut ‘Fuji’ apple slices were studied during 30 days storage at 4, 10 and 20 °C. Instrumental mechanical–acoustic texture evaluations were carried out, and cell wall materials were isolated from the flesh tissue by means of an ethanol and methanol–chloroform solvents extraction procedure. The emphasis was on relating the macroscopic loss of fresh texture characteristics to the changes in the rheological properties occurring to the structuring elements of the cell wall materials (CWMs). The rheology of the reconstituted CWM water dispersion was evaluated by means of oscillatory dynamic testing, and viscoelastic data were interpreted according to the ‘weak-gel model’ theory. The dynamics of the flowing components at the mesoscale structural level was related to the texture softening, which yields decrease in firmness and rigidity parameters, and an attenuation of the acoustic emission (fewer acoustic peaks and lower sound pressure level), as it was measured in the combined acoustic–mechanical test. The kinetic reaction rate values are presented. Softening of apple flesh is accompanied by slight cleavage of molecular assemblies and a loss in cell adhesion, mediated by the increase in assemblies’ water uptake. The ability to handle the relationship between the sounds produced during flesh crushing and the structure of the cellular tissue would assist breeders and geneticists in the selection and control of the apple crispness, or would support technologists in preventing postharvest softening during storage and retail.

Controlled atmosphere-related injury in ‘Honeycrisp’ apples is associated with γ-aminobutyrate accumulation

Chiu, G. Z., Shelp, B. J., Bowley, S. R., DeEll, J. R. and Bozzo, G. G. 2015. Controlled atmosphere-related injury in ‘Honeycrisp’ apples is associated with γ-aminobutyrate accumulation. Can. J. Plant Sci. 95: 879–886. ‘Honeycrisp’ apples (Malus×domestica Borkh.), including fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), can be susceptible to controlled atmosphere (CA)-related injury of the flesh tissue during storage. To better understand the biomarkers associated with this physiological disorder, we compared the temporal responses of the universal stress signature, γ-aminobutyrate (GABA), and visual symptoms of CA-related injury in apples subjected to elevated CO2. Fruit were treated with or without 1-MCP prior to CA [2.5 kPa O2, 5 (elevated) or 0.03 (ambient) kPa CO2] storage at either 3 or 20°C for up to 24 wk. At 20°C, 1-MCP-treated apples displayed symptoms of CA-related injury by 3 wk of elevated CO2 storage; a similar 15% disorder incidence was apparent by 6 wk in non 1-MCP-treated fruit. A maximal incidence of 30% for this disorder occurred after 24 wk at 3°C in fruit held at elevated CO2, regardless of 1-MCP treatment. At 20°C, GABA levels were 48% higher within 6 wk of the transfer of 1-MCP-treated fruit to elevated CO2. At 3°C, a 2.6-fold increase in GABA level occurred by week 6 of elevated CO2 storage, and was maintained for an additional 18 wk thereafter; a similar change in GABA level was apparent in non 1-MCP-treated fruit, albeit delayed until week 18 of storage. These findings indicate that shifts in GABA are associated with the onset of visual symptoms of CA-related injury in ‘Honeycrisp’ fruit in response to elevated CO2, regardless of 1-MCP.

Antioxidant Activity, Total Phenolic and Total Flavonoid Content in Sixty Varieties of Potato (Solanum tuberosum L.) Grown in Ireland

Potatoes accumulate phenolic compounds, which may have health-promoting effects. In this study, the skin and flesh tissues of 60 varieties of potato planted in two trial sites were evaluated for total phenolics, total flavonoids and antioxidant activity. Higher levels of total phenolics, total flavonoids and antioxidant activity were found in the skin than in the flesh of tubers. Blue variety ‘Congo’ showed the highest values in both tissues, except antioxidant activity in the skin which was higher in variety ‘Edzell Blue’. Maximum values in skin and flesh, respectively, were 12.6 and 3.6 mg/g gallic acid equivalents for total phenolics, 9.5 and 2.3 mg/g catechin equivalents for total flavonoids and 18.8 and 4.4 mg/g Trolox equivalents for antioxidant activity on a dry-weight basis. Strong positive correlations were found among total phenolics, total flavonoids and antioxidant activity. Site and year of cultivation significantly affected the three parameters studied.

Antihypertensive peptide purified from Styela clava flesh tissue stimulates glucose uptake through AMP-activated protein kinase (AMPK) activation in skeletal muscle cells

Previously, our group described an antihypertensive peptide (Ala-His-Ile-Ile-Ile, MW: 565.3 Da) with angiotensin I-converting enzyme inhibitory and vasodilatory effects that was purified from Styela clava flesh tissue. In the present study, we investigated the metabolic effects of the antihypertensive peptide in skeletal muscle cells. We found that the antihypertensive peptide stimulated glucose uptake in differentiated L6 rat myoblast cells in a dose-dependent manner. Inhibition of AMP-activated protein kinase (AMPK) by compound C significantly inhibited the antihypertensive peptide-stimulated glucose uptake. Western blotting analyses revealed that the antihypertensive peptide stimulated AMPK phosphorylation and this enhancement could be specifically inhibited by compound C. Furthermore, the current study demonstrates that translocation of glucose transporter-4 (GLUT4) to the plasma membrane was stimulated by the antihypertensive peptide. In summary, the findings from this study suggest that the antihypertensive peptide may have beneficial effects on the glucose metabolism in skeletal muscle cells via a mechanism involving AMPK and possible stimulation of the intrinsic activity of GLUT4 transporter.

전복에서의 갈조류 곰피의 섭취 및 phlorotannin 축적

Dietary intake and bioavailability of phorotannins in abalone was investigated after feeding with the phlorotannin-rich brown seaweed Ecklonia stolonifera after 4 days starvation. Reverse-phase high-performance liquid chromatography (RP-HPLC) affords isolation and quantification of the major phlorotannins of 7-phloroeckol and eckol, which were identified by mass spectrometry and nuclear magnetic resonance. Abalone growth and feed consumption rates were similar when fed either with the E. stolonifera or the common feed seaweed Saccharina japonica for 20 days. Throughout the feeding period, 7-phloroeckolol was accumulated in the abalone flesh tissue up to an average of 0.58±0.13 mg/g dry weight after 6 days. Eckol was reached to 0.25±0.05 mg/g dry tissue after 6 days, and maintained the level until end of feeding period. By feeding S. japonica as a control, no phlorotannins were detected in the abalone tissues. Both of the abalone, fed with E. stolonifera or S. japonica, had enzymes that decomposed 7-phloroeckol and eckol in muscle tissues, with similar degradation rates of ?0.05 or less and ?0.05 mg/ml/hr, respectively. Phlorotannins were reduced by constitutive enzymes in abalone tissues. Therefore, value-added abalone containing bioactive phlorotannins can be produced by simply changing the feed to the phlorotannin-rich brown seaweed E. stolonifera 6 days before harvest.

Controlled atmosphere-related injury in ‘Honeycrisp’ apples is associated with g-aminobutyrate accumulation

Chiu, G. Z., Shelp, B. J., Bowley, S. R., DeEll, J. R. and Bozzo, G. G. 2015. Controlled atmosphere-related injury in ‘Honeycrisp’ apples is associated with γ-aminobutyrate accumulation. Can. J. Plant Sci. 95: 879-886. ‘Honeycrisp’ apples (Malus×domestica Borkh.), including fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), can be susceptible to controlled atmosphere (CA)-related injury of the flesh tissue during storage. To better understand the biomarkers associated with this physiological disorder, we compared the temporal responses of the universal stress signature, γ-aminobutyrate (GABA), and visual symptoms of CA-related injury in apples subjected to elevated CO2. Fruit were treated with or without 1-MCP prior to CA [2.5 kPa O2, 5 (elevated) or 0.03 (ambient) kPa CO2] storage at either 3 or 20°C for up to 24 wk. At 20°C, 1-MCP-treated apples displayed symptoms of CA-related injury by 3 wk of elevated CO2 storage; a similar 15% disorder incidence was apparent by 6 wk in non 1-MC...

Cell wall composition of the skin and flesh tissue of crisp and standard texture southern highbush blueberry genotypes

BACKGROUND: Blueberry cultivars with very firm, crisp fruit textures have been developed to increase consumer acceptance and as an aid in production and marketing. The basis for the crisp fruit texture is unknown. OBJECTIVES: The objective of this study was to compare the bioyield force (BF) and cell wall composition of crisp and standard texture blueberry genotypes. METHODS: Bioyield force of seven southern highbush blueberry genotypes having standard (‘Springhigh’, ‘Star’, Windsor’) and crisp (‘Sweetcrisp’, FL06-561, FL06-562, and FL98-325) fruit texture was measured on fresh, whole fruits. Dry weight, alcohol insoluble residue (AIR), uronic acids (UA), and neutral sugars (NS) were then measured on separated flesh and skin tissue. RESULTS: The BF of the standard texture genotypes was significantly less than all four crisp genotypes. There were differences in the dry weight and AIR among genotypes, but these differences did not correspond to crisp and standard texture classes. There was no significant difference among genotypes in the measurement of UA or NS. CONCLUSIONS: These results confirm that there is a phenotypic difference between crisp and standard texture blueberry genotypes that can be detected with BF measurements, but that quantitative differences among total cell wall material, pectins, and neutral sugars were not responsible for the variability of these texture types.

METHODS OF FRUIT TISSUE SAMPLING TO QUANTIFY CALCIUM AND MAGNESIUM CONTENTS TO SEGREGATE APPLES FOR BITTER PIT INCIDENCE

Susceptibility to bitter pit (BP) has been associated with low Ca content and high Mg/Ca ratio in the fruit, which is highly affected by fruit genotype. This study was carried out to identify the best fruit tissue sampling method to assess Ca and Mg contents to segregate apples for BP occurrence. ‘Fuji’ and ‘Catarina’ apples (with low and high susceptibilities to BP, respectively) were segregated in lots without and with BP symptoms, after four months of cold storage (0±0.5°C/95% RH), and then analyzed for Ca and Mg contents by three fruit tissue sampling methods: peel+flesh, peel, and flesh. For peel+flesh, a wedge-shaped segment was cut longitudinally from the fruit, discarding the core tissue. The fruit calyx-end was used for peel (thickness of 2 mm) and flesh (thickness of 2-8 mm) sampling. For peel+flesh and flesh, Ca content was lower and Mg/Ca ratio was higher in fruit with BP in both cultivars. For peel, only in ‘Fuji’, Ca content was lower and Mg/Ca ratio was higher in fruit with BP. In ‘Catarina’, Mg/Ca ratio in the flesh tissue at the calyx-end increased from 1.83 in fruit without BP to 4.56 in fruit with BP (~2.5-fold increase), while in ‘Fuji’ this ratio increased from 0.96 in fruit without BP to 1.29 in fruit with BP (~1.3-fold increase). Therefore, the high susceptibility to BP in ‘Catarina’ might be explained by its high Mg/Ca ratio in the flesh tissue under the peel, at the calyx-end of the fruit, were the symptoms appeared. Nonetheless, the results show that the Mg/Ca ratio in the flesh at the calyx-end is more suitable to segregate apple fruit for BP susceptibility in both cultivars.

IMPACT OF HEAT SANITATION OF FRESH WHOLE CANTALOUPE ON FRUIT QUALITY AND VOLATILE METABOLISM

Harmful microorganisms can contaminate fresh fruits and vegetables and with this cause outbreaks of foodborne illness. Therefore, mitigation strategies are needed to eliminate or restrict the multiplication of potential pathogens while maintaining fresh produce quality. This study assessed a vapour heat treatment on the control of Listeria on whole fresh cantaloupes (Cucumis melo) and its impact on quality, composition and fruit physiology. Fruit inoculated with Listeria innocua, a non-pathogenic surrogate of Listeria monocytogenes, were treated with 84°C vapour heat for 240 s, followed by storage at 4, 7 or 10°C for 0, 7, 10 or 14 days. At these times, fruit were analyzed for visual appearance, firmness, soluble solids, titratable acidity, flesh colour, respiration rate, and volatile production. On average, the heat treatment achieved 4-log reductions in surrogate pathogen densities. However, the heat treatment caused discoloration of the rind affecting the visual quality of whole fruit. No discoloration or deterioration of flesh tissue, change in flesh firmness, soluble solids or titratable acids was associated with the heat treatment. Fruit respiration measured after warming fruit to 20°C was reduced in heat-treated fruit throughout storage, averaging a CO2 production rate of 16.2 compared to 38.2 mg/kg h for non-heated fruit. This suggested permanent physiological damage occurred to the rind tissue. Heat treatments reduced acetaldehyde, had no effect on ethanol and increased ethyl acetate emissions. Storage at 10°C stimulated the emission of all three volatiles. The heat treatment stimulated the production of methyl, ethyl and acetate esters, but inhibited ester production during storage at temperatures that induced ripening. The vapour heat treatment was an effective sanitation treatment, but caused injury to the melon rind. Therefore, this treatment has potential to ensure safety of fresh-cut melon products.

Anti-inflammatory effect of enzymatic hydrolysates from Styela clava flesh tissue in lipopolysaccharide-stimulated RAW 264.7 macrophages and in vivo zebrafish model.

BACKGROUND/OBJECTIVESIn this study, potential anti-inflammatory effect of enzymatic hydrolysates from Styela clava flesh tissue was assessed via nitric oxide (NO) production in lipopolysaccahride (LPS) induced RAW 264.7 macrophages and in vivo zebrafish model.MATERIALS/METHODSWe investigated the ability of enzymatic hydrolysates from Styela clava flesh tissue to inhibit LPS-induced expression of pro-inflammatory mediators in RAW 264.7 macrophages, and the molecular mechanism through which this inhibition occurred. In addition, we evaluated anti-inflammatory effect of enzymatic hydrolysates against a LPS-exposed in in vivo zebrafish model.RESULTSAmong the enzymatic hydrolysates, Protamex-proteolytic hydrolysate exhibited the highest NO inhibitory effect and was fractionated into three ranges of molecular weight by using ultrafiltration (UF) membranes (MWCO 5 kDa and 10 kDa). The above 10 kDa fraction down-regulated LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), thereby reducing production of NO and prostaglandin E2 (PGE2) in LPS-activated RAW 264.7 macrophages. The above 10 kDa fraction suppressed LPS-induced production of pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. In addition, the above 10 kDa fraction inhibited LPS-induced phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinase (JNK), and p38. Furthermore, NO production in live zebrafish induced by LPS was reduced by addition of the above 10 kDa fraction from S. clava enzymatic hydrolysate.CONCLUSIONThe results of this study suggested that hydrolysates derived from S. clava flesh tissue would be new anti-inflammation materials in functional resources.

A constitutive model for mechanical response characterization of pumpkin peel and flesh tissues under tensile and compressive loadings.

Enhancing quality of food products and reducing volume of waste during mechanical operations of food industry requires a comprehensive knowledge of material response under loadings. While research has focused on mechanical response of food material, the volume of waste after harvesting and during processing stages is still considerably high in both developing and developed countries. This research aims to develop and evaluate a constitutive model of mechanical response of tough skinned vegetables under postharvest and processing operations. The model focuses on both tensile and compressive properties of pumpkin flesh and peel tissues where the behaviours of these tissues vary depending on various factors such as rheological response and cellular structure. Both elastic and plastic response of tissue were considered in the modelling process and finite elasticity combined with pseudo elasticity theory was applied to generate the model. The outcomes were then validated using the published results of experimental work on pumpkin flesh and peel under uniaxial tensile and compression. The constitutive coefficients for peel under tensile test was α = 25.66 and β = -18.48 Mpa and for flesh α = -5.29 and β = 5.27 Mpa. under compression the constitutive coefficients were α = 4.74 and β = -1.71 Mpa for peel and α = 0.76 and β = -1.86 Mpa for flesh samples. Constitutive curves predicted the values of force precisely and close to the experimental values. The curves were fit for whole stress versus strain curve as well as a section of curve up to bio yield point. The modelling outputs had presented good agreement with the empirical values and the constructive curves exhibited a very similar pattern to the experimental curves. The presented constitutive model can be applied next to other agricultural materials under loading in future.

Chilling-related cell damage of apple (Malus × domestica Borkh.) fruit cortical tissue impacts antioxidant, lipid and phenolic metabolism.

'Soggy breakdown' (SB) is an internal flesh disorder of 'Honeycrisp' apple (Malus × domestica Borkh.) fruit that occurs during low temperature storage. The disorder is a chilling injury (CI) in which visible symptoms typically appear after several weeks of storage, but information about the underlying metabolism associated with its induction and development is lacking. The metabolic profile of flesh tissue from wholly healthy fruit and brown and healthy tissues from fruit with SB was characterized using gas chromatography-mass spectrometry (GC-MS) and liquid chromatograph-mass spectrometry (LC-MS). Partial least squares discriminant analysis (PLS-DA) and correlation networks revealed correlation among ester volatile compounds by composition and differences in phytosterol, phenolic and putative triacylglycerides (TAGs) metabolism among the tissues. anova-simultaneous component analysis (ASCA) was used to test the significance of metabolic changes linked with tissue health status. ASCA-significant components included antioxidant compounds, TAGs, and phytosterol conjugates. Relative to entirely healthy tissues, elevated metabolite levels in symptomatic tissue included γ-amino butyric acid, glycerol, sitosteryl (6'-O-palmitoyl) β-d-glucoside and sitosteryl (6'-O-stearate) β-d-glucoside, and TAGs containing combinations of 16:0, 18:3, 18:2 and 18:1 fatty acids. Reduced metabolite levels in SB tissue included 5-caffeoyl quinate, β-carotene, catechin, epicatechin, α-tocopherol, violaxanthin and sitosteryl β-d glucoside. Pathway analysis indicated aspects of primary metabolism differed according to tissue condition, although differences in metabolites involved were more subtle than those of some secondary metabolites. The results implicate oxidative stress and membrane disruption processes in SB development and constitute a diagnostic metabolic profile for the disorder.

Calcium content and its correlated distribution with skin browning spot in bagged Huangguan pear.

Skin browning spot (SBS) is an important physiology disorder that often occurs in bagged fruit at the mature stage in the Huangguan (Pyrus bretschneideri × Pyrus pyrifolia) pear. Using atomic absorption spectrometry, X-ray microanalysis, and the potassium-pyroantimonate precipitation method, the water-soluble and total Ca(2+), Mg(2+), and K(+) contents, their microdistribution, and the Ca(2+) localization were investigated in bagged Huangguan pear fruit in the presence and absence of SBS. Our results show that the water-soluble and total Ca(2+) contents in both the skin and flesh tissue and the total Ca(2+) content only in the skin tissue of the fruits with SBS were significantly lower compared to those of the fruits without SBS. However, a higher K(+) content in the skin tissue was found in the fruits with SBS. There were no significant differences in the water-soluble and total Mg(2+) contents in the skin and flesh tissue between the fruits with and without SBS. In addition, the results of the X-ray microanalysis were consistent with changes in the total Ca(2+), Mg(2+), and K(+) contents in the skin and flesh tissue of the pear fruit that were affected by SBS. Compared to the skin tissue of pear fruit without SBS and the healthy part near the lesion zone of SBS, the lesion zone of SBS exhibited a high accumulation of Ca(2+) grains in the cell membrane of the epidermis cells, while fewer Ca(2+) grains were found in the vacuoles and cell walls. Altogether, these results indicate that Ca(2+) deficiency and the cellular Ca(2+) distribution in skin tissue contributed to the occurrence of SBS in bagged Huangguan pear fruit.

Study on Surface Dot Piting of Lingwu Long Jujubes

The experiment was carried to study a new storage disease of Lingwu long jujubes —surface dot piting and its incidence regularity .There was no abnormal fruit at room temperature ,while fruits storage at lower temperature started to appear concave spots on the seventh to tenth day. The size and distribution of spots are irregular ,and flesh browning and ligneous occurred at the lesion site. SEM results showed that relatived to the peel of the healthy fruit, the microstructure of the epidermal tissue of the lesion site was uneven and rough ,which showed large areas of uniform crack band, and the flesh tissue is messy, with varying degrees of wrinkles, looser organization, or seriously damaged. There was significant negative correlation between this new storage disease and storage temperature, whereas no correlation with gas composition, humidity or other storage conditions.

Effects of location within the tree canopy on carbohydrates, organic acids, amino acids and phenolic compounds in the fruit peel and flesh from three apple (Malus × domestica) cultivars.

Fruits from three cultivars of apple (Malus × domestica Borkh.)—‘McIntosh’, ‘Gala’ and ‘Mutsu’—were harvested from the exterior and interior of the tree canopy. Peel and flesh tissues were sampled separately to determine how the position of the fruit on the tree might affect the levels of the primary and secondary metabolites in the fruit. Fruit from the outer-canopy had a higher fresh weight and a higher soluble solids content compared with inner-canopy fruit. Both the flesh and peel of the outer-canopy fruit had higher concentrations of soluble sugars and sugar alcohols, but lower starch concentrations than the inner-canopy fruit. Canopy position did not significantly affect malic acid concentrations, except in the peel of ‘McIntosh’ and the flesh of ‘Mutsu’. Although levels of ascorbic and succinic acids were higher in the peel of the outer-canopy fruit, the responses of other organic acids to canopy position depended on tissue type and cultivar. Except for histidine, lysine, threonine and glycine, most amino acids accumulated at higher concentrations in the inner-canopy fruit. By contrast, levels of phenolic compounds from both the peel and flesh were significantly higher in the outer-canopy fruit. The significant effects of location within the canopy on both primary metabolites and secondary metabolites demonstrate the importance of light exposure on apple fruit quality.

Evidence for Apoplasmic Phloem Unloading in Pear Fruit

Pear is a tree fruit species with worldwide distribution and belongs to the Rosaceae family. In this study, the phloem unloading pathway in pear (Pyrus bretschneideri ‘Yali’) fruit was investigated using transmission electron microscopy coupled with a symplasmic tracer dye, carboxyfluorescein diacetate (CFDA). Structurally, the sieve element-companion cell (SE-CC) complex in the phloem cells of major and minor sepal bundles is symplasmically isolated to its surrounding parenchyma cells (PCs) throughout fruit development. This was demonstrated by movement of the fluorescent dye which was restricted to phloem cells only without apparent diffusion. Meanwhile, different sugar contents were examined in fruit phloem exudates, with the results indicating that sorbitol comprised about 70 % of total soluble sugars. Gene transcription of a putative plasma membrane sorbitol transporter (PbSOT1) in flesh tissues enclosing the phloem was examined by RT-qPCR, showing that the transcripts were present at all stages of fruit development, but highest in young fruits. These results potentially suggest that the phloem unloading pathway in the pear fruit is mainly via the apoplasm rather than the symplasm.

Relationship between pollination and cell wall properties in common fig fruit

Most botanical types in fig Ficus carica require pollination to fulfil their development and ensure quality onset of the fruit. Cell wall behaviour and composition was followed in fig fruit in response to pollination during maturity. Figs, when ripe, soften drastically and lose of their firmness and cell wall cohesion. Pollination increased peel thickness, flesh thickness, fresh weight and dry matter content of the fruit. Alcohol insoluble solids (AIS), more concentrated in the flesh tissue, were not influenced by the lack of pollination. Concentrations in uronic acids were higher in the AIS of the peel than that of the flesh and differences were significant between pollinated and non-pollinated fruits. Pectin polymers in figs were high methylated (DM>50). The methylation degree (DM) increased more with pollination affecting textural properties of the fig receptacle. The major neutral sugars from the AIS were glucose (Glc) from cellulose followed by arabinose (Ara). No significant changes in neutral sugars content could be allocated to pollination. Pollination is essential in fruit enlargement and softening. Minor changes were determined in the cell wall composition of the fruit at maturity. Fertile seeds resulting from pollination may possibly take place in hormonal activity stimulating many related enzymes of the wall matrix depolymerisation in particular polygalacturonase (PG) and pectin methylesterase (PME).

Collagen: Basis of Life

Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals, making up about 25% of the whole-body protein content. Collagens represent a large family of proteins and at least 28 different collagen types have been described so far which are genetically, chemically and immunologically distinct. All collagens are composed of three polypeptide alpha chains coiled around each other to form the triple-helix configuration, which are stabilized by numerous hydrogen bonds. The primary structural motif of mature collagen is (Gly-X-Pro/Hyp) n . Every third residue is glycine, which is preceded by either a prolyl or a hydroxyprolyl residue. Collagen biosynthesis takes place both intra and extracellularly. It is synthesized by fibroblasts, chondroblasts, osteoblasts and other cells. Degradation of collagen also involves two pathways, the major intracellular collagenase independent and the extracellular collagenase mediated. Collagen related diseases such as osteogenesis imperfecta, ehler danlos syndrome, scurvy, epidermolysis bullosa, collagenopathy most commonly arise from mutations in the collagen genes or the genes encoding some of the enzymes involved in the post-translational modifications in normal collagen production. Through this is a review article, we aim to discuss the various aspects of collagen and its clinical implications in periodontal health and disease.