Lamina Tissue Research Articles

BMSC-derived extracellular vesicles promoted osteogenesis via Axin2 inhibition by delivering MiR-16-5p

Osteoporosis (OP) is a systemic bone disease caused by an imbalance in osteogenesis and osteoclastic resorption. Extracellular vesicles (EVs)-encapsulated miRNAs from bone mesenchymal stem cells (BMSCs) have been reported to participate in osteogenesis. MiR-16-5p is one of the miRNAs that regulates osteogenic differentiation; however, studies have shown that its role in osteogenesis is controversial. Thus, this study aims to investigate the role of miR-16-5p from BMSC-derived extracellular vesicles (EVs) in osteogenic differentiation and uncover the underlying mechanisms. In this study, we used an ovariectomized (OVX) mouse model and an H2O2-treated BMSCs model to investigate the effects of BMSC-derived EVs and EV-encapsulated miR-16-5p on OP and the underlying mechanisms. Our results proved that the miR-16-5p level was significantly decreased in H2O2-treated BMSCs, bone tissues of OVX mice, and lumbar lamina tissues from osteoporotic women. EVs-encapsulated miR-16-5p from BMSCs could promote osteogenic differentiation. Moreover, the miR-16-5p mimics promoted osteogenic differentiation of H2O2-treated BMSCs, and the effects exerted by miR-16-5p were mediated by targeting Axin2, a scaffolding protein of GSK3β that negatively regulates the Wnt/β-catenin signaling pathway. This study provides evidence that EVs-encapsulated miR-16-5p from BMSCs could promote osteogenic differentiation by repressing Axin2.

Artificial lamina after laminectomy: Progress, applications, and future perspectives.

In clinical practice, laminectomy is a commonly used procedure for spinal decompression in patients suffering from spinal disorders such as ossification of ligamentum flavum, lumbar stenosis, severe spinal fracture, and intraspinal tumors. However, the loss of posterior column bony support, the extensive proliferation of fibroblasts and scar formation after laminectomy, and other complications (such as postoperative epidural fibrosis and iatrogenic instability) may cause new symptoms requiring revision surgery. Implantation of an artificial lamina prosthesis is one of the most important methods to avoid post-laminectomy complications. Artificial lamina is a type of synthetic lamina tissue made of various materials and shapes designed to replace the resected autologous lamina. Artificial laminae can provide a barrier between the dural sac and posterior soft tissues to prevent postoperative epidural fibrosis and paravertebral muscle compression and provide mechanical support to maintain spinal alignment. In this paper, we briefly review the complications of laminectomy and the necessity of artificial lamina, then we review various artificial laminae from clinical practice and laboratory research perspectives. Based on a combination of additive manufacturing technology and finite element analysis for spine surgery, we propose a new designing perspective of artificial lamina for potential use in clinical practice.

Aquaporin 4 is not present in normal porcine and human lamina cribrosa.

Aquaporin 4 is absent from astrocytes in the rodent optic nerve head, despite high expression in the retina and myelinated optic nerve. The purpose of this study was to quantify regional aquaporin channel expression in astrocytes of the porcine and human mouse optic nerve (ON). Ocular tissue sections were immunolabeled for aquaporins 1(AQP1), 4(AQP4), and 9(AQP9), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP) and alpha-dystroglycan (αDG) for their presence in retina, lamina, myelin transition zone (MTZ, region just posterior to lamina) and myelinated ON (MON). Semi- quantification of AQP4 labeling & real-time quantitative PCR (qPCR) data were analyzed in retina and ON tissue. Porcine and control human eyes had abundant AQP4 in Müller cells, retinal astrocytes, and myelinated ON (MON), but minimal expression in the lamina cribrosa. AQP1 and AQP9 were present in retina, but not in the lamina. Immunolabeling of GFAP and αDG was similar in lamina, myelin transition zone (MTZ) and MON regions. Semi-quantitative AQP4 labeling was at background level in lamina, increasing in the MTZ, and highest in the MON (lamina vs MTZ, MON; p≤0.05, p≤0.01, respectively). Expression of AQP4 mRNA was minimal in lamina and substantial in MTZ and MON, while GFAP mRNA expression was uniform among the lamina, MTZ, and MON regions. Western blot assay showed AQP4 protein expression in the MON samples, but none was detected in the lamina tissue. The minimal presence of AQP4 in the lamina is a specific regional phenotype of astrocytes in the mammalian optic nerve head.

Laparoscopic Pancreatoduodenectomy with Resection of the Inferior Vena Cava and Reconstruction with a Peritoneal Patch.

Laparoscopic resection of the inferior vena cava (IVC) during laparoscopic pancreatoduodenectomy (LPD) has never been described. A 32-year-old male with large solid pseudopapillary neoplasm underwent LPD with resection of the IVC and reconstruction by a peritoneal patch (PP). In this indication, the dissection is achieved by resection of the IVC. Kocher maneuver is difficult owing to the caval invasion, and section of the retroportal lamina tissue, before Kocher maneuver, is needed to control the left side of the IVC. Extended lymphadenectomy is not needed because the risk of lymph node invasion is low, and venous resection may be required for severe tumor adhesions without necessary histological invasion, to avoid tumor rupture at high risk of recurrence.1,2 The IVC was clamped by a laparoscopic vascular clamp and reconstructed (5-6 cm) with a PP. The operative duration was 430 min, including IVC clamping for 27 min. The outcome was marked by biliary fistula and 24 days of hospital stay. Histology showed 6 cm tumor without histological invasion of the IVC wall. After 15 months of follow-up, there was no recurrence and no stenosis of the IVC. In our experience, reconstruction of the IVC with a PP is a safe procedure, with no PP-related complications and high patency rate (> 90%).3 CONCLUSION: Laparoscopic resection of the IVC is feasible in highly selected centers. The harvesting of the PP is easier than that of other autologous venous grafts, especially when done by the laparoscopic approach.

Alleviating the adverse effects of deficit irrigation in Flame seedless grapevine via Paulsen interstock

Abstract Using interstock with a potential genetic base is considered more recent and sustainable strategy for mitigating the water deficit. This investigation was carried out on transplant of Flame seedless (Vitis vinifera) grapevine grafted onto two rootstocks namely; Freedom (Vitis champinii x 1613C) and 1103Paulsen (vitis berlandieri x Vitis rupestris) with or without 1103Paulsen as interstock to determine its performance under deficit irrigation condition (50% of field capacity). The results indicated that Paulsen as rootstock or as interstock significantly increased the growth vigor of Flame seedless scion as well as the leaf content of total proline, phenols and sugars. Paulsen rootstock has decreased stomatal conductance, leaf transpiration rate and increased diffusion resistance under 50% deficit irrigation compared with grafting on Freedom rootstock. Moreover, Paulsen as interstock for Flame seedless grafted onto Freedom rootstock significantly increased relative water content accompanied by an increase in thickness of leaf anatomical characters such as midvein, lamina, palisade, xylem and phloem tissue under deficit irrigation compared with grafts without Paulsen interstock. This study suggests that using Paulsen as interstock, can be an adaptation strategy for water stress through controlling in some morphological, chemical physiological and anatomical responses of scion.

Photosynthetic capacity of co-occurring kelp species revealed by in situ measurements

Accurate estimates of productivity of marine macrophytes are crucial to predict the consequences of invasive species expansions and climate-related range shifts on coastal ecosystem functioning and carbon cycling. We examined the potential impacts of climate-driven shifts in the relative abundances of foundation species within a temperate reef system on net primary productivity. Specifically, we estimated productivity rates of 3 co-occurring kelp species (Laminaria hyperborea, L. ochroleuca and Undaria pinnatifida) in contrasting regions of their ranges (centre, leading-edge and invasive, respectively) via in situ photorespirometry methods in Brittany, France. Lamina tissues of cold-temperate L. hyperborea and warm-temperate L. ochroleuca had similar rates of net productivity. The stipes of L. hyperborea, however, displayed much higher rates of productivity and respiration than L. ochroleuca, likely due to the dense macroalgal epiphytes colonising their surface. Our results suggest that replacement of L. hyperborea by L. ochroleuca in the NE Atlantic due to increased dominance or further range expansion of this warm-temperate species might lead to reduced net rates of productivity as a result of increased lamina respiration and reduced photosynthetic capacity of stipes. The invasive kelp U. pinnatifida had high rates of net productivity at saturating light levels (294 µmol O2 g-1 dry weight h-1), 3 times higher than any kelp species ever incubated in situ, helping to explain its high success as an invader. We show that shifts in the distributions and relative abundances of seemingly similar foundation species may lead to subsequent changes in net metabolic balance.

Dissecting Metabolism of Leaf Nodules in Ardisia crenata and Psychotria punctata

Root-microbe interaction and its specialized root nodule structures and functions are well studied. In contrast, leaf nodules harboring microbial endophytes in special glandular leaf structures have only recently gained increased interest as plant-microbe phyllosphere interactions. Here, we applied a comprehensive metabolomics platform in combination with natural product isolation and characterization to dissect leaf and leaf nodule metabolism and functions in Ardisia crenata (Primulaceae) and Psychotria punctata (Rubiaceae). The results indicate that abiotic stress resilience plays an important part within the leaf nodule symbiosis of both species. Both species showed metabolic signatures of enhanced nitrogen assimilation/dissimilation pattern and increased polyamine levels in nodules compared to leaf lamina tissue potentially involved in senescence processes and photosynthesis. Multiple links to cytokinin and REDOX-active pathways were found. Our results further demonstrate that secondary metabolite production by endophytes is a key feature of this symbiotic system. Multiple anhydromuropeptides (AhMP) and their derivatives were identified as highly characteristic biomarkers for nodulation within both species. A novel epicatechin derivative was structurally elucidated with NMR and shown to be enriched within the leaf nodules of A. crenata. This enrichment within nodulated tissues was also observed for catechin and other flavonoids indicating that flavonoid metabolism may play an important role for leaf nodule symbiosis of A. crenata. In contrast, pavettamine was only detected in P. punctata and showed no nodule specific enrichment but a developmental effect. Further natural products were detected, including three putative unknown depsipeptide structures in A. crenata leaf nodules. The analysis presents a first metabolomics reference data set for the intimate interaction of microbes and plants in leaf nodules, reveals novel metabolic processes of plant-microbe interaction as well as the potential of natural product discovery in these systems.

Extracellular vesicles released from hiPSC-derived MSCs attenuate chronic prostatitis/chronic pelvic pain syndrome in rats by immunoregulation

BackgroundChronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is an intractable nonbacterial inflammatory disease. Mesenchymal stem cells (MSCs) derived from human induced pluripotent stem cells (hiPSCs, iMSCs) have been well documented for the management of inflammatory and autoimmune disorders because of their powerful immunoregulatory and anti-inflammatory capacities. Recently, studies have indicated that extracellular vesicles (EVs) released from iMSCs hold biological functions similar to their parental cells. This study aimed to evaluate the therapeutic efficacy of EVs released from iMSCs (iMSCs-EVs) on CP/CPPS and to explore the underlying mechanisms.MethodsAn experimental autoimmune prostatitis (EAP) model was established in rats by subcutaneous injection of prostate antigen with adjuvant. Then, iMSCs-EVs were injected into EAP rats via the tail vein. Pain behavioral measurements, urodynamic tests, and histopathological analyses were performed at 2, 4, and 6 weeks. The expression of cyclooxygenase-2 (COX-2) was evaluated by immunofluorescence staining and Western blot. The alterations of B cells, Th1 cells, Th2 cells, Th17 cells, and Treg cells in peripheral blood and spleen were analyzed using flow cytometry. The levels of Th1-, Th2-, Th17-, and Treg-related inflammatory mediators were determined by ELISA.ResultsAfter iMSCs-EVs administration, rats had reduced pain as indicated by the recovery of nociceptive responses to baseline. The voiding pressure was significantly reduced, and the intercontraction interval was increased. The findings of histopathological analysis revealed that iMSCs-EVs could significantly decrease inflammatory cell infiltration and promote basal lamina and glandular epithelial tissue repair. Further studies demonstrated that the overexpression of COX-2 was downregulated by iMSCs-EVs. Meanwhile, the increases in the percentages of Th1 and Th17 cells were dramatically reversed. Also, rats that received iMSCs-EVs showed markedly increased percentages of Treg cells. The levels of those inflammatory mediators showed the same changing tendency.ConclusionsiMSCs-EVs administration has the potential to ameliorate chronic pelvic pain, improve voiding dysfunction, suppress inflammatory reactions, and facilitate prostatic tissue repair. The functions are mediated by downregulating the overexpression of COX-2 and restoring the imbalance of Th1/Th2 and Treg/Th17 cells.

Biochemical and histological evaluation of the characteristics of potential environmental sustainability of hardwood microclones (poplar, birch) grown in experimental nutrient media

Histological characteristics of lamina tissues (numerical values, area of stomata and width of stomatal pore), indicators of photosynthetic and enzymatic activity of the leaves of poplar (Populus alba L. × Populus tremula L.) and birch (Betula pubescens Ehrh.) microclones have been studied as criteria levels of stability degrees of plant tissue resistance to drought and fungal diseases. The stimulation of microclone potential resistance to the effects of various stressors has been revealed when adding a solution of TiO2 and ZnO nanoparticles into a cultivation substrate.

Phytoextraction, phytotransformation and rhizodegradation of ibuprofen associated with Typha angustifolia in a horizontal subsurface flow constructed wetland

Widespread occurrence of trace pharmaceutical residues in aquatic environments is of great concerns due to the potential chronic toxicity of certain pharmaceuticals including ibuprofen on aquatic organisms even at environmental levels. In this study, the phytoextraction, phytotransformation and rhizodegradation of ibuprofen associated with Typha angustifolia were investigated in a horizontal subsurface flow constructed wetland system. The experimental wetland system consisted of a planted bed with Typha angustifolia and an unplanted bed (control) to treat ibuprofen-loaded wastewater (∼107.2 μg L−1). Over a period of 342 days, ibuprofen was accumulated in leaf sheath and lamina tissues at a mean concentration of 160.7 ng g−1, indicating the occurrence of the phytoextraction of ibuprofen. Root-uptake ibuprofen was partially transformed to ibuprofen carboxylic acid, 2-hydroxy ibuprofen and 1-hydroxy ibuprofen which were found to be 1374.9, 235.6 and 301.5 ng g−1 in the sheath, respectively, while they were 1051.1, 693.6 and 178.7 ng g−1 in the lamina. The findings from pyrosequencing analysis of the rhizosphere bacteria suggest that the Dechloromonas sp., the Clostridium sp. (e.g. Clostridium saccharobutylicum), the order Sphingobacteriales, and the Cytophaga sp. in the order Cytophagales were most probably responsible for the rhizodegradation of ibuprofen.

Comparative analysis of the biodiversity of fungal endophytes in insect-induced galls and surrounding foliar tissue

Insect-induced galls are abnormal plant growths that can provide food and shelter to their inhabitants, resulting in stressed plant tissue that may alter the conditions for the colonization or proliferation of endophytic fungi. We investigated the effect gall formation has on fungal endophyte communities and diversity. Using three closely-related gall-forming aphid species that specialize on poplars, we characterized fungal endophyte diversity in galls and surrounding petiole and leaf lamina tissue. A total of 516 fungal endophyte samples were isolated from 272 tissue samples (32 leaves, 31 petioles, and 209 galls), resulting in 23 distinct morphotypes. Despite sharing a common host plant and often forming spatially contiguous galls, the endophyte profiles within the galls of each aphid species were distinct, not only from the galls of the other species, but also from surrounding plant tissue. These results suggest that insect galls can affect the composition of fungal endophyte species in plant tissues, by altering either the colonization or proliferation of their endophytic mycobiota. Likewise, fungal endophytes may be important in the ecology and evolution of insect galls.

Uptake and Distribution of Cd in Sweet Maize Grown on Contaminated Soils: A Field-Scale Study

Maize is an economic crop that is also a candidate for use in phytoremediation in low-to-moderately Cd-contaminated soils, because the plant can accumulate high concentration of Cd in parts that are nonedible to humans while accumulating only a low concentration of Cd in the fruit. Maize cultivars CT38 and HZ were planted in field soils contaminated with Cd and nitrilotriacetic acid (NTA) was used to enhance the phytoextractive effect of the maize. Different organs of the plant were analyzed to identify the Cd sinks in the maize. A distinction was made between leaf sheath tissue and leaf lamina tissue. Cd concentrations decreased in the tissues in the following order: sheath > root > lamina > stem > fruit. The addition of NTA increased the amount of Cd absorbed but left the relative distribution of the metal among the plant organs essentially unchanged. The Cd in the fruit of maize was below the Chinese government's permitted concentration in coarse cereals. Therefore, this study shows that it is possible to conduct maize phytoremediation of Cd-contaminated soil while, at the same time, harvesting a crop, for subsequent consumption.

Progressive Extracellular Matrix Disorganization in Chemically Induced Murine Oral Squamous Cell Carcinoma

Introduction. Oral squamous cell carcinoma (OSCC) is one of the ten most common cancers affecting the human population. Tumor pathogenesis implies a multistep process in which cells acquire features that enable them to become tumorigenic and ultimately malignant. The process of OSCC carcinogenesis can be reproduced in animal models, the OSCC induction with 4-nitroquinoline-1-oxide (4NQO) in mice is a widely used tool for studying tumor pathogenesis. Objective. The aim of the present study was to determine the progressive changes in basal lamina and connective tissue remodeling during 4NQO-induced OSCC carcinogenesis. Material and Methods. Samples were classified according to “International Histological Classification of tumors” in mild, moderate, and severe dysplasia and invasive carcinoma. Five samples of each pathologic entity and control healthy tongues were used. Immunohistochemical analysis of collagen IV as well as histochemical analysis of glycosylated molecules (PAS) and collagen I (Picro Sirius red) were performed. Results. During experimental-induced carcinogenesis by 4NQO a progressive basal lamina destruction and collagen I disorganization in adjacent connective tissue can be observed. Conclusion. Our results confirm previous studies that show alterations in extracellular matrix (ECM) in malignant lesions, validating the experimental carcinogenesis induced by 4NQO.

A petiole-galling insect herbivore decelerates leaf lamina litter decomposition rates

Summary 1. Herbivore-mediated changes in leaf-litter chemistry are often considered responsible for altering litter decomposition rates, but such chemical changes often co-occur with other factors such as physical alteration of leaf material that also influence decomposition rates. We attempted to disentangle these effects using the poplar petiole gall moth (Ectoedemia populella Brusk), which forms galls on petioles at the base of the leaf lamina but does not alter leaf morphology. Thus, differences in leaf decomposition rates between galled and ungalled leaves should be explained by gall-mediated changes in leaf chemistry. 2. Petiole galling decelerated leaf lamina litter decomposition in two Populus host species, but in temporally distinct ways. In Populus granidentata, galling decelerated decomposition by 7% after 4 months. After 12 and 18 months, Populus tremuloides litter decomposition rates were 12% and 17% lower, respectively, in lamina tissue whose petiole had been galled relative to ungalled. On average, the petiole galler increased leaf lamina nitrogen concentrations by 17%, decreased tannin concentrations from 37% to 53% and decreased tannin-binding capacity by 11% and 37% in P. grandidentata and P. tremuloides, respectively. These changes would be expected to increase, rather than decrease, decomposition rates. 3. Unlike other insect herbivores guilds that have variable effects on litter decomposition in direction and magnitude, all gall insects studied to date have decelerated leaf-litter decomposition. This consistent effect of galling on decomposition provides a framework for deciphering a fundamental aspect of insect herbivory on a critical ecosystem process. 4. We used a gall-inducing moth with a distinctive natural history to confirm the role of herbivore-mediated litter chemistry in leaf-litter decomposition dynamics. Moreover, we advance the hypothesis that gall-induced defensive manipulations that protect a host plant from injury by other herbivores lead to decelerated litter decomposition.

Impact of defoliation severity on photosynthesis, carbon metabolism and transport gene expression in perennial ryegrass.

Defoliation severity affects grass regrowth. The changes to biological processes affecting regrowth induced by severe defoliation are not fully understood, nor have they been investigated at a molecular level in field-grown plants. Field-grown perennial ryegrass (Lolium perenne L.) plants were defoliated to 20, 40 or 60mm during winter. Throughout regrowth, transcript profiles of 17 genes involved in photosynthesis and carbon metabolism or transport were characterised in stubble and lamina tissue. Although defoliation to 20mm reduced residual lamina area and stubble water-soluble carbohydrate reserves compared with plants defoliated to 40 or 60mm, net herbage regrowth was not reduced. Transcript profiles indicated a potential compensatory mechanism that may have facilitated regrowth. At the one-leaf regrowth stage, plants defoliated to 20mm had greater abundance of photosynthesis-related gene transcripts (rca, rbcS1, rbcS2, fba, fbp and fnr) and 20% greater stubble total nitrogen than plants defoliated to 60mm. A greater capacity for photosynthesis in outer leaf sheaths may be one potential mechanism used by severely defoliated plants to compensate for the reduced residual lamina area; however, this premise requires further investigation.

Yellowing of disease? Or differentiating for adaptation? Study on Cinnamomum camphora ecotypes

Cinnamomum camphora (L.) Presl is an evergreen broad-leaved tree of the Lauraceae family, widely distributed in the sub-tropical areas in the south of China and used as a virescent tree in urban gardens and streets in Shanghai for its beautiful shape and intensive stress-resistance. However, yellowing of C. camphora in recent years casts doubt about its significance. We believe the green-leaved and yellow-leaved C. camphora might be two different ecotypes, and tentatively refer to the green-leaved C. camphora as C. camphora f. viridis f. nov (CCV) and the yellow-leaved as C. camphora f. flavus f. nov (CCF). We studied their differences and arrived at the following conclusions: 1) compared with CCF, the area of lamina of CCV is significantly larger and the amount of chlorophyll (Chl) significantly higher; 2) the lamina and palisade tissues of CCV are significantly thicker than those of CCF, but its cuticle is significantly thinner; 3) the shape of the stomata of CCV is different from that of the CCF; the stomatal density and stomatal index of CCV are significantly lower than those of CCF. These results show that C. camphora might evolve adaptive differentiation in some aspects which can be used in virescence in urban streets and gardens.

Red (anthocyanic) leaf margins do not correspond to increased phenolic content in New Zealand Veronica spp.

Red or purple coloration of leaf margins is common in angiosperms, and is found in approx. 25 % of New Zealand Veronica species. However, the functional significance of margin coloration is unknown. We hypothesized that anthocyanins in leaf margins correspond with increased phenolic content in leaf margins and/or the leaf entire, signalling low palatability or leaf quality to edge-feeding insects. Five species of Veronica with red leaf margins, and six species without, were examined in a common garden. Phenolic content in leaf margins and interior lamina regions of juvenile and fully expanded leaves was quantified using the Folin-Ciocalteu assay. Proportions of leaf margins eaten and average lengths of continuous bites were used as a proxy for palatability. Phenolic content was consistently higher in leaf margins compared with leaf interiors in all species; however, neither leaf margins nor more interior tissues differed significantly in phenolic content with respects to margin colour. Mean phenolic content was inversely correlated with the mean length of continuous bites, suggesting effective deterrence of grazing. However, there was no difference in herbivore consumption of red and green margins, and the plant species with the longest continuous grazing patterns were both red-margined. Red margin coloration was not an accurate indicator of total phenolic content in leaf margins or interior lamina tissue in New Zealand Veronica. Red coloration was also ineffective in deterring herbivory on the leaf margin, though studies controlling for variations in leaf structure and biochemistry (e.g. intra-specific studies) are needed before more precise conclusions can be drawn. It is also recommended that future studies focus on the relationship between anthocyanin and specific defence compounds (rather than general phenolic pools), and evaluate possible alternative functions of red margins in leaves (e.g. antioxidants, osmotic adjustment).

Morphology and oxidative physiology of sulphur-deficient mulberry plants

The aim of the study was to induce S deficiency symptoms and to relate the generation of reactive oxygen species (ROS) and altered cellular redox environment with the effects of S deficiency in mulberry ( Morus alba L.) cv. Kanva-2 plants. A study of antioxidant responses, malondialdehyde (MDA) content as an indicator of oxidative damage and ratio of dehydroascorbate (DHA) to ascorbic acid (AsA) as an index of cellular redox environment in S-deficient mulberry plants was undertaken. The S deficiency effects appeared as paling of the youngest emerging leaves. Soon, the leaves, as they expanded, became devoid of the green pigment and turned completely yellow. These leaves showed upward curling of the leaf margins and prominent wrinkles in the lamina tissues. Sulphur-deficient plants showed improved leaf water status, as indicated by increases in the degree of succulence (DS), specific water content (SWC), relative water content (RWC) and water potential ( Ψ) of leaves, contained less tissue S concentration, less chloroplastic pigments, decreased tissue Fe and Cu and had improved tissue Mn concentrations. Increased hydrogen peroxide concentration under deficiency of S did not induce oxidative damage as indicated by decreased MDA concentration. The S-deficient plants exhibited significant decreases in the concentrations of DHA and total ascorbate. The ratio DHA/AsA decreased in these plants. While the activity of catalase (EC 1.11.1.6) decreased in S-deficient plants, activities of peroxidase (EC 1.11.1.7), superoxide dismutase (EC 1.15.1.1), and ascorbate peroxidase (EC 1.11.1.11) were increased. The results suggest that deficiency of S induced oxidative stress, however, because of low tissue Fe and Cu and enhanced antioxidant enzymes activities other than catalase, provided ample protection against oxidative challenge to the S-deficient mulberry plants.

In vitro degradation of forage chicory (Cichorium intybus L.) by endopoly‐ galacturonase

AbstractBACKGROUND: Leaves of forage chicory break down rapidly in the rumen despite little or no rumination. Because chicory cell walls contain high concentrations of pectin, degradation of leaf midrib and leaf lamina tissues by pectinolytic enzymes was investigated.RESULTS: Treatment with endopolygalacturonase (endo‐PG) degraded fresh intact chicory leaves to particles of less than 1 mm in length and solubilised more than 70% of the dry matter within 16 h. Uronic acids were released more extensively than neutral monosaccharides. In similar treatments, 77% of white clover leaflets and 12% of perennial ryegrass leaf blades were solubilised or broken down to particles with a size of less than 1 mm. The degradation of pectic polysaccharides in chicory midribs was monitored by immunofluorescence labelling with monoclonal antibodies JIM5 and JIM7 which target partially methyl‐esterified epitopes of the homogalacturonan (HG) domain of pectin. Examination by fluorescence microscopy revealed that cell separation in the cortical parenchyma of chicory midrib following endo‐PG treatment was associated with loss of HG from the middle lamella, the corners of intercellular spaces and from the tricellular junctions.CONCLUSION: The results of the current study suggest that one of the main contributions to chicory breakdown in the rumen may be cell separation caused by degradation of HG by pectinolytic enzymes from rumen bacteria. Copyright © 2007 Society of Chemical Industry

Black coloration in leaves of Ophiopogon planiscapus 'Nigrescens'. Leaf optics, chromaticity, and internal light gradients.

Black-pigmented leaves occur only rarely in nature, possibly because their efficiency of light capture for photosynthesis is low. Using near-isogenic morphs of black- and green-leafed Ophiopogon planiscapus Nakai 'Nigrescens', we tested the possibility that black pigmentation restricts the transmission of PAR within the leaf. We measured chromaticity coordinates of black and green leaf phenotypes, quantified their pigments and optical properties, and followed the transmission profiles of red, blue and green light through lamina tissues. Chroma and lightness values for the black leaves were comparable to those of a black paint standard, and were lower than those for the green phenotype, or for green and anthocyanic leaves of three other species. The adaxial surface of black leaves absorbed 95% incident quanta, and reflected 4% across the entire 400-700 nm waveband. There were no obvious structural differences between black and green leaves. Black coloration correlated with luxuriant concentrations of both chlorophylls and anthocyanins in superficial mesophyll. Profiles of transmission of red and blue light were similar in green and black leaves. In contrast, green light was restricted to uppermost palisade mesophyll layers in black leaves, but was transmitted to more central mesophyll in green leaves.