General regulatory factors exert differential effects on nucleosome sliding activity of the ISW1a complex.

BACKGROUND: Chromatin dynamics is deeply involved in processes that require access to DNA, such as transcriptional regulation. Among the factors involved in chromatin dynamics at gene regulatory regions are general regulatory factors (GRFs). These factors contribute to establishment and maintenance of nucleosome-depleted regions (NDRs). These regions are populated by nucleosomes through histone deposition and nucleosome sliding, the latter catalyzed by a number of ATP-dependent chromatin remodeling complexes, including ISW1a. It has been observed that GRFs can act as barriers against nucleosome sliding towards NDRs. However, the relative ability of the different GRFs to hinder sliding activity is currently unknown. RESULTS: Considering this, we performed a comparative analysis for the main GRFs, with focus in their ability to modulate nucleosome sliding mediated by ISW1a. Among the GRFs tested in nucleosome remodeling assays, Rap1 was the only factor displaying the ability to hinder the activity of ISW1a. This effect requires location of the Rap1 cognate sequence on linker that becomes entry DNA in the nucleosome remodeling process. In addition, Rap1 was able to hinder nucleosome assembly in octamer transfer assays. Concurrently, Rap1 displayed the highest affinity for and longest dwell time from its target sequence, compared to the other GRFs tested. Consistently, through bioinformatics analyses of publicly available genome-wide data, we found that nucleosome occupancy and histone deposition in vivo are inversely correlated with the affinity of Rap1 for its target sequences in the genome. CONCLUSIONS: Our findings point to DNA binding affinity, residence time and location at particular translational positions relative to the nucleosome core as the key features of GRFs underlying their roles played in nucleosome sliding and assembly.

NUAK1 coordinates growth factor-dependent activation of mTORC2 and Akt signaling.

BACKGROUND: mTORC2 is a critical regulator of cytoskeleton organization, cell proliferation, and cancer cell survival. Activated mTORC2 induces maximal activation of Akt by phosphorylation of Ser-473, but regulation of Akt activity and signaling crosstalk upon growth factor stimulation are still unclear. RESULTS: We identified that NUAK1 regulates growth factor-dependent activation of Akt by two mechanisms. NUAK1 interacts with mTORC2 components and regulates mTORC2-dependent activation of Akt by controlling lysosome positioning and mTOR association with this organelle. A second mechanism involves NUAK1 directly phosphorylating Akt at Ser-473. The effect of NUAK1 correlated with a growth factor-dependent activation of specific Akt substrates. NUAK1 induced the Akt-dependent phosphorylation of FOXO1/3a (Thr-24/Thr-32) but not of TSC2 (Thr-1462). According to a subcellular compartmentalization that could explain NUAK1's differential effect on the Akt substrates, we found that NUAK1 is associated with early endosomes but not with plasma membrane, late endosomes, or lysosomes. NUAK1 was required for the Akt/FOXO1/3a axis, regulating p21CIP1, p27KIP1, and FoxM1 expression and cancer cell survival upon EGFR stimulation. Pharmacological inhibition of NUAK1 potentiated the cell death effect induced by Akt or mTOR pharmacological blockage. Analysis of human tissue data revealed that NUAK1 expression positively correlates with EGFR expression and Akt Ser-473 phosphorylation in several human cancers. CONCLUSIONS: Our results showed that NUAK1 kinase controls mTOR subcellular localization and induces Akt phosphorylation, demonstrating that NUAK1 regulates the growth factor-dependent activation of Akt signaling. Therefore, targeting NUAK1, or co-targeting it with Akt or mTOR inhibitors, may be effective in cancers with hyperactivated Akt signaling.

Melatonin and Vitamins as Protectors against the Reproductive Toxicity of Bisphenols: Which Is the Most Effective? A Systematic Review and Meta-Analysis.

Bisphenols such as bisphenol A (BPA), S (BPS), C (BPC), F (BPF), AF (BPAF), tetrabromobisphenol, nonylphenol, and octylphenol are plasticizers used worldwide to manufacture daily-use articles. Exposure to these compounds is related to many pathologies of public health importance, such as infertility. Using a protector compound against the reproductive toxicological effects of bisphenols is of scientific interest. Melatonin and vitamins have been tested, but the results are not conclusive. To this end, this systematic review and meta-analysis compared the response of reproductive variables to melatonin and vitamin administration as protectors against damage caused by bisphenols. We search for controlled studies of male rats exposed to bisphenols to induce alterations in reproduction, with at least one intervention group receiving melatonin or vitamins (B, C, or E). Also, molecular docking simulations were performed between the androgen (AR) and estrogen receptors (ER), melatonin, and vitamins. About 1234 records were initially found; finally, 13 studies were qualified for review and meta-analysis. Melatonin plus bisphenol improves sperm concentration and viability of sperm and increases testosterone serum levels compared with control groups; however, groups receiving vitamins plus bisphenols had lower sperm concentration, total testis weight, and testosterone serum levels than the control. In the docking analysis, vitamin E had the highest negative MolDock score, representing the best binding affinity with AR and ER, compared with other vitamins and melatonin in the docking. Our findings suggest that vitamins could act as an endocrine disruptor, and melatonin is most effective in protecting against the toxic effects of bisphenols.

Poly(dA:dT) Tracts Differentially Modulate Nucleosome Remodeling Activity of RSC and ISW1a Complexes, Exerting Tract Orientation-Dependent and -Independent Effects.

The establishment and maintenance of nucleosome-free regions (NFRs) are prominent processes within chromatin dynamics. Transcription factors, ATP-dependent chromatin remodeling complexes (CRCs) and DNA sequences are the main factors involved. In Saccharomyces cerevisiae, CRCs such as RSC contribute to chromatin opening at NFRs, while other complexes, including ISW1a, contribute to NFR shrinking. Regarding DNA sequences, growing evidence points to poly(dA:dT) tracts as playing a direct role in active processes involved in nucleosome positioning dynamics. Intriguingly, poly(dA:dT)-tract-containing NFRs span asymmetrically relative to the location of the tract by a currently unknown mechanism. In order to obtain insight into the role of poly(dA:dT) tracts in nucleosome remodeling, we performed a systematic analysis of their influence on the activity of ISW1a and RSC complexes. Our results show that poly(dA:dT) tracts differentially affect the activity of these CRCs. Moreover, we found differences between the effects exerted by the two alternative tract orientations. Remarkably, tract-containing linker DNA is taken as exit DNA for nucleosome sliding catalyzed by RSC. Our findings show that defined DNA sequences, when present in linker DNA, can dictate in which direction a remodeling complex has to slide nucleosomes and shed light into the mechanisms underlying asymmetrical chromatin opening around poly(dA:dT) tracts.

Microbiota composition in the lower respiratory tract is associated with severity in patients with acute respiratory distress by influenza.

Several factors are associated with the severity of the respiratory disease caused by the influenza virus. Although viral factors are one of the most studied, in recent years the role of the microbiota and co-infections in severe and fatal outcomes has been recognized. However, most of the work has focused on the microbiota of the upper respiratory tract (URT), hindering potential insights from the lower respiratory tract (LRT) that may help to understand the role of the microbiota in Influenza disease. In this work, we characterized the microbiota of the LRT of patients with Influenza A using 16S rRNA sequencing. We tested if patients with different outcomes (deceased/recovered) and use of antibiotics differ in their microbial community composition. We found important differences in the diversity and composition of the microbiota between deceased and recovered patients. In particular, we detected a high abundance of opportunistic pathogens such as Granulicatella, in patients either deceased or with antibiotic treatment. Also, we found antibiotic treatment correlated with lower diversity of microbial communities and with lower probability of survival in Influenza A patients. Altogether, the loss of microbial diversity could generate a disequilibrium in the community, potentially compromising the immune response increasing viral infectivity, promoting the growth of potentially pathogenic bacteria that, together with altered biochemical parameters, can be leading to severe forms of the disease. Overall, the present study gives one of the first characterizations of the diversity and composition of microbial communities in the LRT of Influenza patients and its relationship with clinical variables and disease severity.

The linker histone Hho1 modulates the activity of ATP-dependent chromatin remodeling complexes.

Diverse factors play roles in chromatin dynamics, including linker proteins. Among them are high mobility group (HMG) box family proteins and linker histones. In the yeast Saccharomyces cerevisiae, Hmo1 has been identified as an HMG-box protein. This protein displays properties that are in agreement with this allocation. However, a number of studies have postulated that Hmo1 functions as a linker histone in yeast. On the other hand, when discovered, the Hho1 protein was identified as a linker histone. While multiple studies support this classification, some findings point to characteristics of Hho1 that are dissimilar to those commonly assigned to linker histones. In order to better understand the roles played by Hmo1 and Hho1 in chromatin dynamics and transcriptional regulation, we performed several analyses directly comparing these two proteins. Our analyses of genome-wide binding profiles support the belonging of Hmo1 to the HMGB family and Hho1 to the linker histones family. Interestingly, by performing protein-protein interaction analyses we found that both Hmo1 and Hho1 display physical interaction with the ATP-dependent chromatin remodeling complexes RSC, ISW1a and SWI/SNF. Moreover, by carrying out nucleosome remodeling assays, we found that both proteins stimulate the activity of the ISW1a complex. However, in the case of RSC, Hmo1 and Hho1 displayed differential properties, with Hho1 mainly showing an inhibitory effect. Our results are in agreement with the opposite roles played by RSC and ISW1a in chromatin dynamics and transcriptional regulation, and expand the view for the roles played by Hho1 and linker histones.

Visual Acuity and Number of Amniotic Membrane Layers as Indicators of Efficacy in Amniotic Membrane Transplantation for Corneal Ulcers: A Multicenter Study.

BACKGROUND: To evaluate new indicators in the efficacy of amniotic membrane transplantation (AMT) for non-healing corneal ulcers (NHCUs). METHODS: Retrospective, multicenter study. In total, 223 AMTs for NHCU in 191 patients were assessed. The main outcomes studied were the success rate of AMT (complete re-epithelization), postoperative visual acuity (VA) gain, and number of AM layers transplanted. RESULTS: The overall AMT success rate was 74.4%. In 92% of our patients VA stability or improvement. Postoperative VA was significantly higher than preoperative VA in the entire cohort (p < 0.001) and in all etiological groups of ulcers (post-bacterial, p ≤ 0.001; post-herpetic, p ≤ 0.0038; neurotrophic ulcers, p ≤ 0.014; non-rheumatic peripheral, p ≤ 0.001; and ulcers secondary to lagophthalmos and eyelid malposition or trauma, p ≤ 0.004). Most participants (56.5%) presented a preoperative VA equal to or less than counting fingers (≤0.01). Of these, 13.5% reached a postoperative VA equal to or better than legal blindness (≥0.05) after AMT. A higher success rate was observed in the monolayer than in the multilayer AMT (79.5% and 64.9%, respectively; p = 0.018). No statistically significant values were found between the number of layers transplanted and VA gain (p = 0.509). CONCLUSION: AMT is not only beneficial in achieving complete re-epithelialization in NHCUs but also in improving postoperative VA; these improvements are independent of etiologies of ulcers. Furthermore, the use of monolayer AMT seems to be a more appropriate option than multilayer AMT for NHCU since the multilayer AMT did not present better outcomes (success rate and VA gain) compared to monolayer AMT in the different types of ulcers studied.

Underexpression of endothelial nitric oxide synthase leads to more severe pulmonary complex vascular lesions associated with HIV patients / La baja expresión de oxido nítrico sintetasa provoca mayor severidad en las lesiones vasculares complejas asociadas al VIH

Abstract Background: Despite increase in survival of human immunodeficiency virus (HIV) patients due to highly active antiretroviral therapy, non-infectious complications are still prevalent such as presentation of lung vasculopathy, even in asymptomatic patients. Endothelial nitric oxide synthase (eNOS) is necessary to produce nitric oxide that causes pulmonary endothelial vasodilation. Participation of this protein in the pulmonary circulation in HIV patients has not been elucidated. This work studied the presence and expression of eNOS in pulmonary complex vascular lesions associated with HIV (PCVL/HIV). Methods: In lung tissues from patients who died from complications of HIV, we used immunohistochemistry and immune chemiluminescence (imageJ) to determine the different degrees of expression of eNOS in PCVL-HIV in comparison with non-PCVL/HIV. Reagents used were anti-eNOS and an automated system. All data are presented as mean and standard deviation. Differences were analyzed with Wilcoxon; p < 0.05 was accepted as statistically significant. Results: In 57 tissues, the histological evidence of pulmonary vasculopathy was showed as different types (proliferative, obliterative, and plexiform) and severe presentation of vasculopathy than non-PCVL/HIV. A statistically significant decrease of eNOS was observed in all PCVL/HIV tissue samples. Conclusion: eNOS has a relevant role in the pathogenesis of pulmonary vasculopathy in acquired immunodeficiency syndrome patients. It is necessary to determine in the future the participation of eNOS and other mechanisms involved in PCVL/HIV.

Resumen Antecedentes: A pesar del incremento en la sobrevivencia del paciente con virus de inmunodeficiencia humana (VIH) debido al uso del tratamiento antiretroviral altamente efectivo, las complicaciones no infecciosas siguen ocasionando vasculopatía pulmonar, aun en pacientes asintomáticos. La óxido nítrico sintetasa (ONSe) es necesaria para la producción de óxido nítrico la cual provoca vasodilatación pulmonar. La participación de esta proteína en la circulación pulmonar en los pacientes con VIH aún no se ha dilucidado. Este trabajo estudia la presencia y la expresión de ONSe en las lesiones vasculares pulmonares complejas asociadas al VIH (LVPC/VIH). Métodos: En tejidos pulmonares de pacientes que fallecieron por complicaciones del VIH, se utilizó inmunohistoquímica e inmunoquimioluminescencia (imageJ) para determinar los diferentes grados de expresión de la ONSe en LVPC/VIH. Los reactivos utilizados son anti-ONSe en sistema automatizado. Todos los datos son presentados en media y desviación estándar. Las diferencias son analizadas con la prueba de Wilcoxon; se aceptó como estadísticamente significativa una p < 0.05. Resultados: En 57 pacientes, la histología de la vasculopatía pulmonar mostró diferentes tipos (proliferativo, obliterativo y plexiforme) además de varias presentaciones de vasculopatía en tejidos no-LVPC/VIH. Se observó diferencia estadística en la disminución de ONSe en todos los tejidos LVPC/VIH. Conclusiones: La ONSe tiene un papel relevante en la patogénesis de la vasculopatía pulmonar en el VIH. Es necesario determinar en el futuro la participación de ONSe y otros mecanismos involucrados en LVPC/VIH.

Underexpression of endothelial nitric oxide synthase leads to more severe pulmonary complex vascular lesions associated with HIV patients.

Background: Despite increase in survival of human immunodeficiency virus (HIV) patients due to highly active antiretroviral therapy, non-infectious complications are still prevalent such as presentation of lung vasculopathy, even in asymptomatic patients. Endothelial nitric oxide synthase (eNOS) is necessary to produce nitric oxide that causes pulmonary endothelial vasodilation. Participation of this protein in the pulmonary circulation in HIV patients has not been elucidated. This work studied the presence and expression of eNOS in pulmonary complex vascular lesions associated with HIV (PCVL/HIV). Methods: In lung tissues from patients who died from complications of HIV, we used immunohistochemistry and immune chemiluminescence (imageJ) to determine the different degrees of expression of eNOS in PCVL-HIV in comparison with non-PCVL/HIV. Reagents used were anti-eNOS and an automated system. All data are presented as mean and standard deviation. Differences were analyzed with Wilcoxon; p < 0.05 was accepted as statistically significant. Results: In 57 tissues, the histological evidence of pulmonary vasculopathy was showed as different types (proliferative, obliterative, and plexiform) and severe presentation of vasculopathy than non-PCVL/HIV. A statistically significant decrease of eNOS was observed in all PCVL/HIV tissue samples. Conclusion: eNOS has a relevant role in the pathogenesis of pulmonary vasculopathy in acquired immunodeficiency syndrome patients. It is necessary to determine in the future the participation of eNOS and other mechanisms involved in PCVL/HIV.

Antecedentes: A pesar del incremento en la sobrevivencia del paciente con virus de inmunodeficiencia humana (VIH) debido al uso del tratamiento antiretroviral altamente efectivo, las complicaciones no infecciosas siguen ocasionando vasculopatía pulmonar, aun en pacientes asintomáticos. La óxido nítrico sintetasa (ONSe) es necesaria para la producción de óxido nítrico la cual provoca vasodilatación pulmonar. La participación de esta proteína en la circulación pulmonar en los pacientes con VIH aún no se ha dilucidado. Este trabajo estudia la presencia y la expresión de ONSe en las lesiones vasculares pulmonares complejas asociadas al VIH (LVPC/VIH). Métodos: En tejidos pulmonares de pacientes que fallecieron por complicaciones del VIH, se utilizó inmunohistoquímica e inmunoquimioluminescencia (imageJ) para determinar los diferentes grados de expresión de la ONSe en LVPC/VIH. Los reactivos utilizados son anti-ONSe en sistema automatizado. Todos los datos son presentados en media y desviación estándar. Las diferencias son analizadas con la prueba de Wilcoxon; se aceptó como estadísticamente significativa una p < 0.05. Resultados: En 57 pacientes, la histología de la vasculopatía pulmonar mostró diferentes tipos (proliferativo, obliterativo y plexiforme) además de varias presentaciones de vasculopatía en tejidos no-LVPC/VIH. Se observó diferencia estadística en la disminución de ONSe en todos los tejidos LVPC/VIH. Conclusiones: La ONSe tiene un papel relevante en la patogénesis de la vasculopatía pulmonar en el VIH. Es necesario determinar en el futuro la participación de ONSe y otros mecanismos involucrados en LVPC/VIH.

A Trichostatin A (TSA)/Sp1-mediated mechanism for the regulation of SALL2 tumor suppressor in Jurkat T cells.

SALL2 is a transcription factor involved in development and disease. Deregulation of SALL2 has been associated with cancer, suggesting that it plays a role in the disease. However, how SALL2 is regulated and why is deregulated in cancer remain poorly understood. We previously showed that the p53 tumor suppressor represses SALL2 under acute genotoxic stress. Here, we investigated the effect of Histone Deacetylase Inhibitor (HDACi) Trichostatin A (TSA), and involvement of Sp1 on expression and function of SALL2 in Jurkat T cells. We show that SALL2 mRNA and protein levels were enhanced under TSA treatment. Both, TSA and ectopic expression of Sp1 transactivated the SALL2 P2 promoter. This transactivation effect was blocked by the Sp1-binding inhibitor mithramycin A. Sp1 bound in vitro and in vivo to the proximal region of the P2 promoter. TSA induced Sp1 binding to the P2 promoter, which correlated with dynamic changes on H4 acetylation and concomitant recruitment of p300 or HDAC1 in a mutually exclusive manner. Our results suggest that TSA-induced Sp1-Lys703 acetylation contributes to the transcriptional activation of the P2 promoter. Finally, using a CRISPR/Cas9 SALL2-KO Jurkat-T cell model and gain of function experiments, we demonstrated that SALL2 upregulation is required for TSA-mediated cell death. Thus, our study identified Sp1 as a novel transcriptional regulator of SALL2, and proposes a novel epigenetic mechanism for SALL2 regulation in Jurkat-T cells. Altogether, our data support SALL2 function as a tumor suppressor, and SALL2 involvement in cell death response to HDACi.

Impact of food processing on rye product properties and their in vitro digestion.

PURPOSE: Rye products have been reported to elicit postprandial insulin and glucose responses which may be beneficial for prevention of type-2 diabetes. However, mechanisms underlying variations in responses related to processing techniques are not fully understood. METHODS: Five differently processed rye products (sourdough-fermented bread, fermented and unfermented crispbread, extrusion-cooked rye, and porridge) and refined wheat bread were characterised. Two in vitro methods, a dynamic method simulating digestion in the stomach and small intestine and a static method, simulating conditions in the stomach were used to determine viscosity development, structural changes and release of glucose during digestion. RESULTS: Structural and compositional differences induced by processing influenced product digestion. Gastric disintegration and digesta particle size were related to characteristics of the starch/protein matrix, while digesta viscosity was reduced due to fibre degradation during fermentation. More cohesive boluses were associated with slower glucose release. Sourdough fermentation increased amylose leakage and appeared to inhibit starch hydrolysis despite low digesta viscosity and rapid disintegration. CONCLUSIONS: The net release of glucose during digestion of foods is determined by several factors which may vary in their importance depending on product specific properties.

Influence of seasonal variation and ultra high temperature processing on lipid profile and fat globule structure of Swedish cow milk.

To investigate the effects of seasonal variations and processing on cow milk fat, raw milk collected in six individual months and corresponding ultra high temperature (UHT) milk were analyzed. Similar seasonal variations in lipid classes and fatty acid composition were found in raw and UHT milk. Under commercial processing, lipid content was standardized to approximately 1.5% in UHT milk. Decreased diameter of fat droplets (around 1µm) and thinner globule membranes were observed, as revealed using confocal laser scanning microscopy (CLSM). The distribution of lipid classes was modified with a decreased proportion of triacylglycerol accompanied by the increase of phospholipids and free fatty acids. Saturated fatty acids C12:0 and C14:0, trans-fatty acids including conjugated linoleic acid (CLA), polyunsaturated fatty acids C18:2(n-6) and C18:3(n-3), showed increased proportions in UHT milk. These results provide an indication of the effect of UHT processing on milk lipid properties.

Role of Nhp6 and Hmo1 in SWI/SNF occupancy and nucleosome landscape at gene regulatory regions.

Diverse chromatin modifiers are involved in regulation of gene expression at the level of transcriptional regulation. Among these modifiers are ATP-dependent chromatin remodelers, where the SWI/SNF complex is the founding member. It has been observed that High Mobility Group (HMG) proteins can influence the activity of a number of these chromatin remodelers. In this context, we have previously demonstrated that the yeast HMG proteins Nhp6 and Hmo1 can stimulate SWI/SNF activity. Here, we studied the genome-wide binding patterns of Nhp6, Hmo1 and the SWI/SNF complex, finding that most of gene promoters presenting high occupancy of this complex also display high enrichment of these HMG proteins. Using deletion mutant strains we demonstrate that binding of SWI/SNF is significantly reduced at numerous genomic locations by deletion of NHP6 and/or deletion of HMO1. Moreover, alterations in the nucleosome landscape take place at gene promoters undergoing reduced SWI/SNF binding. Additional analyses show that these effects also correlate with alterations in transcriptional activity. Our results suggest that, besides the ability to stimulate SWI/SNF activity, these HMG proteins are able to assist the loading of this complex onto gene regulatory regions.

The CREB Transcription Factor Controls Transcriptional Activity of the Human RIC8B Gene.

Proper regulation of gene expression is essential for normal development, cellular growth, and differentiation. Differential expression profiles of mRNA coding for vertebrate Ric-8B during embryo and adult stages have been observed. In addition, Ric-8B is expressed in few cerebral nuclei subareas. These facts point to a dynamic control of RIC8B gene expression. In order to understand the transcriptional regulation of this gene, we searched for cis-elements in the sequence of the human RIC8B promoter region, identifying binding sites for the basic/leucine zipper (bZip) CREB transcription factor family (CRE sites) and C/EBP transcription factor family (C/EBP sites). CRE sites were found clustered near the transcription start site, while the C/EBP sites were found clustered at around 300 bp upstream the CRE sites. Here, we demonstrate the ability of CREB1 and C/EBPß to bind their respective elements identified in the RIC8B promoter. Comparative protein-DNA interaction analyses revealed only the proximal elements as high affinity sites for CREB1 and only the distal elements as high affinity sites for C/EBPß. Chromatin immunoprecipitation analyses, carried out using a human neuroblastoma cell line, confirmed the preferential association of CREB to the proximal region of the RIC8B promoter. By performing luciferase reporter assays, we found the CRE sites as the most relevant elements for its transcriptional activity. Taken together, these data show the existence of functional CREB and C/EBP binding sites in the human RIC8B gene promoter, a particular distribution of these sites and demonstrate a relevant role of CREB in stimulating transcriptional activity of this gene. J. Cell. Biochem. 117: 1797-1805, 2016. © 2016 Wiley Periodicals, Inc.

Improved material properties of solution-cast starch films: Effect of varying amylopectin structure and amylose content of starch from genetically modified potatoes.

High-amylose potato starches were produced through genetic modification resulting in changed granule morphology and composition, with higher amylose content and increased chain length of amylopectin. The increased amylose content and structural changes in amylopectin enhanced film-forming behavior and improved barrier and tensile properties in starch films. The molecular structure in these starches was related to film-forming properties. Solution-cast films of high-amylose starch revealed a homogeneous structure with increasing surface roughness at higher amylose content, possibly due to amylose aggregation. Films exhibited significantly higher stress and strain at break compared with films of wild-type starch, which could be attributable to the longer chains of amylopectin being involved in the interconnected network and more interaction between chains, as shown using transmission electron microscopy. The oxygen permeability of high-amylose starch films was significantly decreased compared with wild-type starch. The nature of the modified starches makes them an interesting candidate for replacement of non-renewable oxygen and grease barrier polymers used today.