Presence Of PL Research Articles

The juxtaposition of Cambrian and early Ordovician magmatism in the Tafí del Valle area. Characteristics and recognition of Pampean and Famatinian magmatic suites in the easternmost Sierras Pampeanas

Along more than 1000 km, the boundary between the Pampean and Famatinian belts separates the Cambrian magmatism to the east (540-515 Ma) from the easternmost granitic rocks ascribed to the Famatinian orogeny to the west (early Ordovician). The geochronological and geochemical study presented in this work has revealed the first Cambrian magmatism in the Sierras de Aconquija and Cumbres Calchaquíes at the northeastern edge of the Famatinian belt. Pabellón (522 ± 2.8 Ma) and Ñuñorco Grande (478.3 ± 2.3 Ma) intrusive units form part of the small plutons exposed together in the Tafí del Valle area, which have been related according to their geochemical characteristics. The good correlation observed between ages and characteristic geochemical signatures have motivated the comparison with other intrusive complexes along the Pampean and eastern Famatinian belts, resulting in regional diagnostic geochemical features and a petrogenetic and evolutive proposal for the Cambrian and early Ordovician magmatism in the eastern Sierras Pampeanas. Easternmost early Ordovician granitic rocks constitute a calcic, weak to moderately peraluminous series. They are Sr-rich tonalitic to monzogranitic magmas (SiO2 >62 %wt.) with steep REE patterns, positive and negative Eu anomalies, high Sr/Y and moderate Ce/Yb ratios. Accordingly, the water-fluxed melting of a mafic source under high to moderate pressures may be involved in the origin of silica- and Ca-rich parental magma. The shallower evolution of these melts consists of Pl-dominated fractionation trends that finally constituted Pl-rich crystal mushes (tonalites) and more felsic residual liquids. Regarding Cambrian granodiorites and monzogranites, any petrogenetic scheme must consider the magnesian, high-K calc-alkalic characteristics for a short-range silica variation, low to moderate peraluminosity and high zircon saturation temperatures (>850 °C). Source conditions are determined by the presence of Pl and Hbl in the solid assemblage based on the REE patterns. These geochemical characteristics point to the extensive HT-LP melting of a dominantly crustal source, probably assisted by the injection of hot H2O-rich mafic melts.

Application of integrated clustering and petrophysical-microscopic methods for facies determination of Campanian–Maastrichtian and Danian–Thanetian reservoirs: Constraints for tectonostratigraphic influences on sedimentation across the NW Indian Plate margin

This paper focuses on reservoirs study in tectonostratigraphic perspective using soft computing multivariate statistical technique of clustering analysis (CA) to delineate electrofacies (EF) for rock typing. The EF knowledge was combined with petrophysics, rock fabric number (rfn) and application of microscopic studies comprising thin sections (TS), scanning electron microscopy (SEM), back scattered electron (BSE) and energy dispersive X-Ray spectroscopy (EDS) on fauna acquired from novel drill cuttings of selected wells. The methods were implemented on data of eight exploratory wells from eastern Sulaiman sedimentary basin (Pakistan) to investigate tectonostratigraphic influences and reservoir characteristics of the Campanian–Maastrichtian, and Danian–Thanetian reservoirs. The Danian-Thanetian (Upper and Lower Ranikot Formations) demonstrate good reservoir rocks in the Sulaiman Fold Belt (SFB) and the northern part of the Zindapir (ZA), however, in the Sulaiman Depression (SD), the Danian-Thanetian reservoirs are shale-rich bearing poor reservoir potential based on EF log correlation. The presence of glauconite (Gl) in the Paleocene Ranikot intervals suggests transgressive (TST) or early highstand system tract (HST) for this particular formation. This evidence is further supported by the occurrence of planktonic foraminifera (Pl), the abundance of which is indicative of late TSTs and early stage HSTs. The presence of Pl in the Campanian Parh Limestone indicates an open sea environment. The clay minerals (kaolinite, chlorite, montmorillonite) occurrence in Maastrichtian Pab Sandstone suggest the detrimental effect on reservoir quality, hindering permeability and fluid flow, proposing this particular formation as a tight reservoir. The kaolinite clay type in the Lower Ranikot Sands in the northern part of ZA characterize continental to near-shore sediments, indicative of fluviatile environment. The Maastrichtian Mughal Kot Formation in the SFB indicates arkosic sandstone (feldspar-rich) with some micaceous content and montmorillonite.The findings from the EF correlation of different wells demonstrate that the reservoir rocks in the SD to the southeast are more shale rich in comparison to those encountered in the SFB in the northeast and northwest. The rfn suggests class 1 type rock fabric (grain dominant) for the Cretaceous Parh Limestone. Due to incomplete logging data, it was not possible to derive rfn for Paleocene formations. The results validate the reservoir heterogeneities on microscopic and small-scale using drill cuttings and well logs.Geologically, active tectonics during the Cretaceous and Paleocene, local sea level fluctuations, diagenesis, clay mineralogy and paleo-topography have strongly affected the lateral variation of facies of Campanian–Maastrichtian, and Danian–Thanetian reservoirs. Moreover, regional active tectonics (Himalayan Orogeny) spanning the Cretaceous and Paleogene Periods also played a major role in crafting the reservoir architecture of various rock units. The results demonstrate the Campanian–Maastrichtian and Danian–Thanetian reservoirs as promising exploratory targets in the SFB. The comparison of the achieved outcomes showed a close agreement with the lateral facies variation in Cretaceous (Campanian–Maastrichtian) and Paleocene (Danian–Thanetian) across the study area.

Nano-complexation of ε-poly-l-lysine with DNA: Improvement of antimicrobial activity under high phosphate conditions.

ε-Poly-l-lysine (PL) has high antimicrobial activity and a wide antimicrobial spectrum and is applied broadly in the food industry. However, PL may lose part of its activity in phosphate systems, which are typically used in seafood processing. To enhance antimicrobial activity under high phosphate conditions, DNA/PL nanoparticles were fabricated via the nanoprecipitation method. The DNA/PL nanoparticle size was smallest when the ethanol to water ratio was 7:1, and the mean diameter was 101 nm. UV-vis showed hypochromism and a redshift of the DNA in the presence of PL, indicating an intercalative interaction between DNA and PL. FTIR spectroscopy revealed that strong hydrogen bonds and hydrophobic interactions were involved in DNA/PL nanoparticle formation. Compared with that of PL, the antimicrobial activity of the nanoparticles against S. aureus, B. subtilis, and E. coli was enhanced. Additionally, the DNA/PL nanoparticles still retained higher antimicrobial activity in the phosphate system than free PL. The antimicrobial mechanistic analysis provided evidence that the DNA/PL nanoparticles showed high bioactivity due to cell membrane damage. This work provides a potential method to enhance the antimicrobial activity of PL under adverse conditions, which can promote the application of PL in seafood containing phosphate compounds.

P2.16-34 Visceral Pleural Invasion is Closely Associated with Nodal Spread in cStage IA Lung Adenocarcinoma

Survival outcomes of patients with clinical Stage IA (cIA) lung adenocarcinoma (LAD) are favorable after resections. In this decade, limited resection without lymphnodes dissections have been indicated for selected cases based on the radiological findings and intraoperative hilar explorations, while we sometimes experience occult lymphnodes metastases among them. These facts refer that limited resections could potentially induce underestimation of the disease, local failure and worsened patients’ prognoses. In the present study, we retrospectively investigate the clinicopathological and oncogenic factors in association with the occult nodal spread and skip metastases, and aim to identify population for standard resection in cIA LAD. We retrospectively investigated 287 patients with cIA LAD who underwent standard pulmonary resections with mediastinal dissections from January 2013 through December 2017. Clinicopathological factors including location of the tumor, radiological pleural invasion and oncogenic status (EGFR/KRAS/ALK/Triple Negative) were reviewed for outcomes of occult nodal spread and skip metastasis. According to the ROC curves analyses, cutoff values of total diameter (TD), solid diameter (SD), mediastinal window diameter (MD) in CT image and pathological invasive size (IS) were settled to diagnose nodal metastases and skip pN2, respectively. Among 287 patients with cIA LAD, 34 (11.8%) with lymph node metastases and 8 (2.8%) with pN2 without hilar metastases (skip pN2) were identified. Univariate analyses revealed that high serum CEA level, TD, MD, SUVmax, IS and pathological pleural invasion (pl) were predictive for nodal metastases. And multivariate analysis showed that pl was closely associated with nodal metastases (Odds Ratio: 3.3, p=0.007). Furthermore, multivariate analysis following the univariate analyses also showed that presence of pl was the factor closely associated with skip N2 metastases (Odds Ratio: 5.7, p=0.029), whereas radiological findings nor oncogenic status were not so. In the clinical valuables, serum CEA level, SD, MD, SUVmax were significantly associated with pl. In resected cIA LAD, pathological pleural invasion was closely associated with both occult nodal spread and skip pN2, while any other preoperative factors and oncogenic status were not. New diagnostic modalities for pl may provide the candidates for standard resections in cIA LAD.

Transformations of Titanium(IV) Butoxide on Magnetite Surface in the Presence of Pluronic P-123

The technique of producing magnetically operated nanocomposites Fe3O4/TiO2 with high specific surface area (to 320 m2/g) was developed. A copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (Pluronic-123) was used as a template. The processes of converting n-butylortotytanatu (BOT) in TiO2 on the surface of magnetite in the presence of PL when heated, and the structure, magnetic and adsorption properties of nanocomposites Fe3O4/TiO2 were investigated. It is shown that the maximum temperature of the heat treatment of nanocomposites is 500 ºC. It was established that the specific saturation magnetization (σs) of nanocomposites Fe3O4/TiO2 by varying the content of PL ranges from 3.75 to 3.96 μT·m3/kg, while coercive force Hc – 1.47-1.61 kA/m. Adsorption complexes such as Fe3O4/TiO2/DNA were obtained.

Evaluation of the growth and osteogenic differentiation of ASCs cultured with PL and seeded on PLGA scaffolds.

Scaffold serves as an important component of tissue engineering, which facilitates cell attachment, proliferation and differentiation of cultured cells. In this study we aimed to use platelet lysates as a substitute for FBS in culturing and proliferation of human adipose tissue-derived stromal cells (ASCs), which constitute a promising source for cell therapy. We characterized ASCs in the presence of PL, and then we seeded them onto poly(lactic-co-glycolic acid) (PLGA) scaffolds, osteogenic media was used to induce their proliferation and osteogenic differentiation. Gene expression analysis revealed higher expression of osteogenic related genes, immunohistochemical staining showed proper cell attachment, growth and collagen matrix formation with the ability to induce vascularization. In conclusion, expansion of ASCs in PL-supplemented medium could promote cell proliferation and osteogenic differentiation of cells seeded on PLGA scaffolds, therefore it could be considered as a suitable and effective substitute for FBS to be used in clinical applications.

Combined effects of selected food additives on adhesion of various foodborne pathogens onto microtiter plate and cabbage leaves

Abstract The study was conducted to examine the adhesion inhibition and antibacterial activities by combined use of some selected food additives such as Sucrose Fatty Acid Ester (SE) C18, Gardenia Yellow (GY), Monascus Pigment (MP), Protamine (PT), e-polylysine (PL) and Milk Serum Protein (MSP), against Salmonella Enteritidis, Salmonella Typhimurium, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus. The adhesion of those pathogenic bacteria was reduced by several combination of food additives compared to that of each of the single use. The combinations decreased the relative adhesion more than 10% compared to that of each of the single use were taken into consideration. The following combinations such as SE18 & GY, PT & MSP, and PL & MSP were effective in inhibiting the attachment of S. Enteritidis onto microtiter plate compared to that of each of the single use. In case of S. Typhimurium, the combination of MSP & MP, SE18 & GY, SE18 & PT, SE18 & PL, SE18 & MP, SE18 & MSP, MP & PT, MSP & PL, GY & PL, and MSP & PT were effective in adhesion inhibition. The combination of SE18 & GY, GY & MSP, and PL & MSP were effective in inhibiting the attachment of P. aeruginosa onto microtiter plate compared to that of each of the single use. The combination of GY & MSP, MSP & PT or PL and MP & PL were effective to inhibit the attachment of L. monocytogenes. The adhesion of S. aureus was reduced by combined use of SE18 & PT, GY & PT, GY & PL, MSP & GY, MSP & PL, SE18 & GY, SE18 & MP, and MSP & PT compared to that of each of the single use. On the other hand, there were no such significant changes in viable counts of all pathogenic bacteria tested by using combination of food additives compared to that of each of the single use. However, the viable counts of S. Enteritidis and P. aeruginosa decreased drastically in the presence of PL (0.01%) and PT (1%), respectively and reached to the lower detection limit. In addition, the viable counts of L. monocytogenes decreased around 4 Log in the presence of PL. These results clearly showed that the combination of MSP and PT or PL effectively reduced adhesion of all the Gram-positive and negative pathogens tested on the microtiter plate. The pretreatment of cabbage leaves with combination of PL & MSP was also effective to reduce the viable counts of secondary-contaminated S. Enteritidis on the cabbage leaves by washing with water compared to that of untreated cabbage leaves.

High concentrations of pyridoxal stimulate the expression of IGFBP1 in HepG2 cells through upregulation of the ERK/c-Jun pathway

Increasing evidence suggests that dietary vitamin B6 is linked to the prevention of cancer and cardiovascular disease. However, the molecular mechanisms involved in this process are not yet understood. Preliminary results in the current study indicated, following DNA microarray analysis and quantitative PCR, that insulin‑like growth factor‑binding protein 1 (IGFBP1) mRNA is upregulated in HT29 colon carcinoma cells exposed to pyridoxal (PL, 500 µM). IGFBP1 is secreted from the liver and is hypothesized to exert a protective role in the development of cancer and cardiovascular disease. Thus, further experiments were performed to investigate the effect of PL on the expression of IGFBP1 in HepG2 hepatocellular carcinoma cells. The addition of PL (500 µM) markedly increased the expression of IGFBP1 mRNA in HepG2 cells at 6, 12 and 24 h (P<0.01), whereas other vitamers (500 µM), including pyridoxal 5'‑phosphate (PLP), pyridoxine (PN) and pyridoxamine (PM), caused no such effect. The expression of the IGFBP1 protein in the cell lysate and culture medium was elevated in the presence of PL. PL elevated expression of the active form of ERK1 protein, p‑ERK1, and the p‑c‑Jun protein, a downstream factor of ERK. Furthermore, IGFBP1 expression, elevated by PL, was suppressed by PD98059, an ERK inhibitor. Higher expression of IGFBP1 protein by PL was suppressed by cycloheximide. These results suggest that PL may induce the expression of IGFBP1 in hepatoma cells via a mechanism involving the ERK/c‑Jun pathway.

A novel mechanism of Enhancing the Haemostatic Effect in the Combination with Recombinant Factor VIII and Activated Prothrombin Complex Concentrate(APCC) in Hemophilia A Patients with Inhibitor

Abstract 1178We have reported that factor (F)VIIa/tissue factor (TF) rapidly activated FVIII by proteolysis of the heavy chain (HCh), and that appeared to serve physiologically as an activator for up-regulation of FVIII activity in very early-timed coagulation phase (J Thromb Haemost. 2010;8:2494). Furthermore, the activation phase could be observed even in the presence of anti-FVIII inhibitors, independently of their types of kinetic and epitope of inhibitors, whilst the inactivation was moderated by anti-C2 with type 1 behavior (Thromb Haemost. 2011;105:989). More recently, the other group has reported that the combination of FVIII and bypassing agent, APCC, also potentiated the thrombin generation in hemophilia A plasmas with inhibitors (Klintman et al. Br J Haematol. 2010;151:381), but the mechanisms have remained unknown. In this study, we investigated the hemostatic effect of the combination therapy with APCC and FVIII. We first examined FVIII activation catalyzed by APCC in one-stage clotting assay. The activity level of FVIII (10 nM) elevated rapidly by ∼3-fold within 1 min after addition of APCC (0.05 U/mL)/TF (0.5 nM), and subsequently decreased to the initial level within 10 min. However, the addition of APCC without TF little affected FVIII activity within 10 min, but after then gradually elevated its activity. The presence of E-76, FVIIa-specific inhibitor, significantly moderated the reaction triggered by APCC/TF, but hirudin, FIIa-specific inhibitor, little affected this activation. We further evaluated the velocity of APCC-induced thrombin generation in the presence or absence of FVIII. The increase rate of thrombin production triggered by APCC/TF in the presence of FVIII was greater than that by APCC/TF in the absence of FVIII by ∼1.6-fold, whilst the increase was little observed in the absence of TF. To clarify its enhancing effects, we performed APCC-catalyzed FVIII cleavage in SDS-PAGE and Western blot. APCC contains FVII (mainly active form) and FII, FIX and FX (mainly non-active forms). In general, FVIIa/TF, FIIa, and FXa rapidly proteolyze the HCh at Arg372 (and Arg740), and FVIIa/TF and FXa proteolyze at Arg336. FVIII proteolysis by FVIIa/TF is dependent on the presence of PL, but not FIIa. Interestingly, APCC/TF proteolyzed the HCh at Arg372 and Arg740, followed by at Arg336 in the presence of PL, whilst did not proteolyze in its absence. The presence of TF accelerated the proteolysis by ∼6.6-fold compared to the absence of TF. However, the addition of E-76 significantly delayed these cleavages. These findings supported that APCC as well as rFVIIa possessed a potential to activation/inactivation of FVIII in early-timed coagulation phase, and that FVIIa in APCC appeared to play a major role in APCC-catalyzed FVIII activation/inactivation. Furthermore, to confirm this enhancing effect in the presence of anti-FVIII inhibitors, we prepared the anti-FVIII inhibitor IgGs (3 of anti-A2, 4 of anti-C2 with type 1, and 2 of anti-C2 with type 2). The presence of anti-FVIII inhibitors did not significantly affect the APCC-catalyzed FVIII activation (by ∼3-fold), independently of their epitopes, in one-stage clotting assay. Of surprise, anti-C2 with type 1 significantly moderated APCC-catalyzed FVIIIa inactivation, and the peak level of FVIIIa retained over 30 min. In contrast, the other inhibitors little affected this inactivation, similar to FVIIa/TF-catalyzed FVIII reaction. In conclusion, we demonstrated the putative mechanism of enhancing hemostatic effects in the combination therapy using FVIII and APCC. In addition, only a small amount of APCC relative to the standard dosage (1–2 U/mL) for clinical use could activate FVIII even in the presence of anti-FVIII inhibitors, and this combination therapy would provide new therapeutic strategy in congenital hemophilia A with inhibitor and/or acquired hemophilia A. Disclosures:Yada:Baxter Hemophilia Scientific Research and Education Fund 2011: Research Funding. Nogami:Bayer Award 2009: Research Funding.

Platelet Pathology in GATA-1 Dyserythropoietic Macrothrombocytopenia.

Germline mutations in the X-linked hematopoietic transcription factor, GATA-1, have been associated with dyserythropoietic anemia (DEA), macrothrombocytopenia (MTP), and congenital erythropoietic porphyria. Recently, morphological features suggestive of the Gray Platelet Syndrome (GPS) were described in a pedigree with a germline R216Q GATA-1 mutation (Blood 106:6a, 2005). The present study has evaluated platelets (Pl) in the electron microscope from members of a previously described pedigree (Blood 98:2681–2688, 2001) with GATA-1 G208S, MTP, and dyserythropoiesis without anemia, for whom detailed platelet morphology studies have not been reported. The presence of a hemizygous GATA-1 mutation was confirmed by conventional fluorescent dye chemistry sequencing of DNA from patient peripheral blood mononuclear cells. Their Pl revealed wide variations in size, shape, internal and external structure. Some normal sized and giant Pl contained usual numbers of alpha granules and dense bodies, while most of the large cells were hypogranular. Some contained no membrane systems or organelles. Others were filled with masses of dense tubular system (DTS) channels, and others contained the tubular inclusions found in the Medich Giant Platelets Disorder (Platelets 15:345–353, 2004). Many of the hypogranular cells contained small vacuoles that may have been enclosing membranes of alpha granules. Except for the tubular inclusions, all of these structural variations are observed in GPS Pl (Am. J. Pathol. 95:445–462, 1979). However, additional striking abnormalities were seen in GATA-1 Pl that are not characteristic of GPS Pl. Many GATA-1 Pl contained unusual, closely associated dense double membranes differing from normal elements of rough endoplasmic reticulum, smooth endoplasmic reticulum, DTS or surface connected open canalicular system (OCS), but resembling channels of the OCS after exposure to EDTA. They were observed previously only in megakaryocytes (Mk) from one family with GATA-1 DEA-MTP (Nat. Genet , 24:266–270, 2000). The dense double membranes were often found in parallel association and, in some examples, isolating areas of cytoplasm. However, the isolated areas were not undergoing autophagic degradation as such areas enclosed by elements of the DTS do in White Platelet Syndrome Pl (Platelets 15:173,2004). Instead, they proved to be another unique feature of GATA-1 platelets, the presence of Pl within Pl. The sequestered cells were usually mature in appearance and often discoid in form with circumferential coils of microtubules. In some GATA-1 Pl there were two Pl within the same cell, and on rare occasions, a Pl within a Pl within a Pl. Pl within Pl have never been observed previously in any human platelet disorder. Another unique feature, related to Pl within Pl, was the frequent Pl to Pl surface attachment of non-activated cells forming large macrothrombocytes with no similarity to aggregates of stimulated normal platelets.Conclusion: The substructural abnormalities of Pl from patients with germline GATA-1 mutations share some overlap with those seen in GPS Pl, but are distinct and unique. The MTP, Pl within Pl and surface Pl to Pl attachments suggest a major defect in the formation and separation of GATA-1 Pl from pro-Pl of the parent Mk, resulting in the MTP characteristic of the disorder.

SOLUBILIZATION OF SOME NON-STEROIDAL ANTIINFLAMMATORY DRUGS (NSAIDs) BY PLURONIC F-127 BLOCK COPOLYMER

This work is an attempt to solubilize certain non-steroidal anti-inflammatory drugs such as Piroxicam (PXM), Ibuprofen (IBU) and Indomethacin (IND), through the use of hydrophilic surfactant pluronic F-127 (Pl. F-127), which was used in different concentrations above its critical micelle concentration (CMC). The solubility of the investigated drugs was enhanced, and was linearly correlated with the surfactant concentration. The effect of temperature on the solubilization capacity of the surfactant and the distribution coefficient of the drugs between the micellar and aqueous phases was determined. It was found that, there is a direct relationship between the solubilization capacity of surfactant toward the used drugs and temperature and there is an inverse relationship between the distribution coefficient and temperature. These observations were more obvious for IBU than IND and PXM. The change in heat of solution (H), free energy (G) and entropy (S) as a result of solubilization of the investigated drugs were calculated. The data prevailed that, the presence of Pl. F-127 energetically favors the solubility of the used drugs and more favorable by increasing the surfactant concentration. The dissolution study was performed for these drugs. Pl. F-127 proved its ability to enhance the dissolution rate of the investigated water insoluble drugs.

Human galectin-1 recognition of poly-N-acetyllactosamine and chimeric polysaccharides.

Human galectin-1 is a dimeric carbohydrate binding protein (Gal-1) (subunit 14.6 kDa) widely expressed by many cells but whose carbohydrate binding specificity is not well understood. Because of conflicting evidence regarding the ability of human Gal-1 to recognize N-acetyllactosamine (LN, Galbeta4GlcNAc) and poly-N-acetyllactosamine sequences (PL, [-3Galbeta4GlcNAcbeta1-]n), we synthesized a number of neoglycoproteins containing galactose, N-acetylgalactosamine, fucose, LN, PL, and chimeric polysaccharides conjugated to bovine serum albumin (BSA). All neoglycoproteins were characterized by MALDI-TOF. Binding was determined in ELISA-type assays with immobilized neoglycoproteins and apparent binding affinities were estimated. For comparison, we also tested the binding of these neoglycoconjugates to Ricinus communis agglutinin I, (RCA-I, a galactose-binding lectin) and Lycopersicon esculentum agglutinin (LEA, or tomato lectin), a PL-binding lectin. Gal-1 bound to immobilized Galbeta4GlcNAcbeta3Galbeta4Glc-BSA with an apparent K(d) of approximately 23 micro M but bound better to BSA conjugates with long PL and chimeric polysaccharide sequences (K(d)'s ranging from 11.9 +/- 2.9 microM to 20.9 +/- 5.1 micro M). By contrast, Gal-1 did not bind glycans lacking a terminal, nonreducing unmodified LN disaccharide and also bound very poorly to lactosyl-BSA (Galbeta4Glc-BSA). By contrast, RCA bound well to all glycans containing terminal, nonreducing Galbeta1-R, including lactosyl-BSA, and bound independently of the modification of the terminal, nonreducing LN or the presence of PL. LEA bound with increasing affinity to unmodified PL in proportion to chain length. Thus Gal-1 binds terminal beta4Gal residues, and its binding affinity is enhanced significantly by the presence of this determinant on long-chain PL or chimeric polysaccharides.

Ultrastructural and biochemical effects of endopectate lyase on cell walls from cell suspension cultures of bean and rice

Cell walls prepared from suspension cell cultures of bean and rice in log-phase growth were used to examine the effects of endopectate lyase (PL) on the solubilization of cell wall carbohydrates and concomitant ultrastructural alterations. Cell wall preparations from both plant sources were heterogeneous and contained a range of wall types from primary walls to xylem elements with spiral, secondary wall thickenings. Marked differences in wall thickness and number of wall laminations typified both preparations.Bean cell walls were more susceptible to degradation by PL than were those of rice. Upon treatment of the former with 2.3 × 10−3 units/mL of PL (1 unit released 1 μmol of unsaturated uronide/min at 30 °C from polygalacturonic acid at pH 8.5), 27% of the noncellulosic wall carbohydrate was solubilized in 1 h. This represented 50% of the PL susceptible carbohydrate in the preparation. Only 3% of the noncellulosic carbohydrate was released from rice cell walls in 1 h when treated with 115 × 10−3 units of PL/mL. This accounted for 60% of the PL susceptible wall fractions. Only uronic acid, rhamnose, galactose, and arabinose were solubilized from both preparations by PL.Cell walls in the bean and rice preparations were affected differentially by the PL. Those walls with secondary thickenings did not appear to be degraded, while the distinct fibrillar appearance of both bean and rice walls tended to fade or disappear. The middle lamella tended to dissolve to varying degrees in the presence of PL. Bean walls were more severely degraded than were the rice walls and many exhibited swelling, separation of wall layers, markedly reduced staining intensity, and (or) a granular ultrastructure.This study has demonstrated that as PL acts on susceptible cell walls there are major changes evoked in cell wall structure which suggest that the rhamnogalacturonan fraction of the higher plant cell wall contributes significantly to cell wall integrity. This study also emphasizes the need for cell wall material of proven uniformity for investigations of both cell wall composition and effects of specific polysaccharide degrading enzymes on cell wall integrity. Preliminary studies indicate that tobacco pith may provide more uniform cell walls than do cell suspension cultures.