Modulation Of Enzymes Research Articles

Exploring the Dynamics of Holo-Shikimate Kinase through Molecular Mechanics

Understanding the connection between local and global dynamics can provide valuable insights into enzymatic function and may contribute to the development of novel strategies for enzyme modulation. In this work, we investigated the dynamics at both the global and local (active site) levels of Shikimate Kinase (SK) through microsecond time-scale molecular dynamics (MD) simulations of the holoenzyme in the product state. Our focus was on the wild-type (WT) enzyme and two mutants (R116A and R116K) which are known for their reduced catalytic activity. Through exploring the dynamics of these variants, we gained insights into the role of residue R116 and its contribution to overall SK dynamics. We argue that the connection between local and global dynamics can be attributed to local frustration near the mutated residue which perturbs the global protein dynamics.

Anxiolytic activity of methanolic extract of Cardia dichotoma leaves in rats

The present study aimed to evaluate the methanolic extract of Cordia dichotoma (MECD) leaves (MECD) for anxiolytic activity in rats. Elevated plus maze test (EPM) and light and dark test were used to evaluate the antianxiety property of MECD. Diazepam (2 mg/kg) and methanolic extract of Cordia dichotoma (50,100, and 200n mg/Kg, p.o.) were administered daily for 21 days. EPM and light and dark tests were assessed on the 7th, 14th, and 21st days. On the 21st day, animals were killed, and the striatum was excised for the estimation of various biochemical parameters like malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) as well as histopathological study. In this study, the (MECD) demonstrated a significant and dose-dependent increase in time spent in the open arm of the elevated plus maze (EPM) test and the time spent in the light compartment in the light & dark test. It also significantly decreased the MDA level and increased CAT, GSH, and SOD levels (p < 0.001) in the MECD-treated group compared to the control group. Furthermore, MECD significantly restored histological abnormalities, revealing reduced stress-induced damage. It is suggested that MECD possessed an anxiolytic effect via modulation of endogenous enzymes in experimental-induced anxiety in rats.

Synthesis, characterization and hypolipidemic effects of urazine derivatives on rat: Study of molecular modeling and enzyme inhibition

The prevalence of hyperlipidemia has increased dramatically worldwide. It is a major public health threat, characterized by the presence of an abnormal lipid profile, primarily with elevated serum total cholesterol (TC), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) levels, and reduced high-density lipoprotein (HDL) level. Genetic factors, dietary and lifestyle habits play important roles in hyperlipidemia. It can increase the risk of chronic metabolic disorders, such as obesity, cardiovascular disease, and type II diabetes. The main objective of the present study was to evaluate the effect of urazine derivatives on serum triglyceride, cholesterol, LDL, HDL, and nitric oxide (NO) levels in high-fat diet (HFD)-induced hyperlipidemic rats. Synthetic compounds were prepared and confirmed by spectroscopic methods. Then, 88 male Sprague-Dawley rats were divided into 11 groups: control, HFD-treated group, HFD plus atorvastatin-treated group, and HFD plus 8 synthetic compounds-treated groups. The body weight, triglyceride, cholesterol, LDL, HDL, and NO levels were measured. The data with p < 0.05 were considered significant. The results indicated that HFD significantly increased cholesterol, triglyceride, and LDL levels and decreased NO concentration and HDL level compared to the control group (p < 0.05). However, HFD plus urazine derivatives significantly decreased NO, cholesterol, and triglyceride levels and increased HDL levels compared to the HFD-treated group (p < 0.05). Urazine derivatives may improve liver dysfunction in HFD-induced hyperlipidemic rats by modulation of detoxification enzymes and their anti-oxidant effects and also blood lipid profile.

Black pepper (Piper nigrum Lam) as a natural feed additive and source of beneficial nutrients and phytochemicals in chicken nutrition

Abstract Tropical countries are rich in medicinal herbs that have the potentials to improve poultry productivity and health by increasing digestive enzyme activity, immune responses, and modulation of gut microbiota composition through the action of their bioactive constituents. Presently, black pepper (BP), one of such tropical herbs is gaining popularity as a substitute for antibiotics in poultry production, which have been found to promote the development of anti-resistant strains of bacteria and incorporation of drug residues in animal products. BP belongs to the genus - Piper, species – nigrum, and family - Piperaceae. The leaves, fruits, and seeds of BP are moderate in essential nutrients such as minerals and vitamins, but low in anti-nutritional factors. It is also high in important bioactive compounds such as polyphenols and flavonoids. These bioactive compounds play important roles in regulating the normal physiological functions of animals such as growth, egg production, and immune responses. Therefore, the aim of this review is to pool evidence on the chemical composition of BP that acts as feed additives and their mode of action in enhancing performance and product quality, as well as the reasons for the inconsistent results among authors on the feed additive value of BP in chicken nutrition.

One-step self-assembly of quantum dot-based spherical nucleic acid nanostructure for accurate monitoring of long noncoding RNA MALAT1 in living cells and tissues

Simple and sensitive measurement of long non-coding RNA (lncRNA) is critical for early detection of malignancies. Herein, we demonstrate one-step self-assembly of quantum dot (QD)-based spherical nucleic acid (SNA) nanostructure for accurate monitoring of lncRNAs in living cells and tissues. When target lncRNA is present, it binds with a dumbbell probe to expose the complementary domain of Cy5-labeled primer, which subsequently induces cascade primer exchange reaction to produce abundant Cy5-labeled initiators. The Cy5-labeled initiators subsequently hybridize with hairpin probes on the QD surface to activate isothermal circular strand-displacement polymerization reaction, generating the QD-DNA-Cy5 nanostructures and inducing efficient Förster resonance energy transfer (FRET) between donor QD and acceptor Cy5. The obtained FRET signals are accurately quantified by single-molecule imaging. Notably, the single QD-based SNA nanostructure functions not only as a signal transmitter but also as a protector against non-specific amplification. Moreover, this assay utilizes only one DNA polymerase to achieve two-stage amplification, avoiding careful modulation of multiple enzymes. The self-assembly of QD nanosensor can be accomplished in single-step and single-tube manners at room temperature, eliminating precise temperature control and labor-intensive reaction protocols. This QD nanosensor achieves high sensitivity with a limit of detection (LOD) of 65.25 aM, and it is capable of quantifying lncRNA expression at single-cell level, differentiate tumor cells from normal cells, and distinguish breast cancer patients from healthy individuals, providing a versatile paradigm for biomedical research and early clinic diagnostics.

Protective role of flavonoids quercetin and silymarin in the viral-associated inflammatory bowel disease: an updated review.

Inflammatory bowel disease (IBD) is a chronic recurrent inflammation of the gastrointestinal tract (GIT). IBD patients are susceptible to various infections such as viral infections due to the long-term consumption of immunosuppressive drugs and biologics. The antiviral and IBD protective traits of flavonoids have not been entirely investigated. This study objective included an overview of the protective role of flavonoids quercetin and silymarin in viral-associated IBD. Several viral agents such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella zoster virus (VZV) and enteric viruses can be reactivated and thus develop or exacerbate the IBD conditions or eventually facilitate the disease remission. Flavonoids such as quercetin and silymarin are non-toxic and safe bioactive compounds with remarkable anti-oxidant, anti-inflammatory and anti-viral effects. Mechanisms of anti-inflammatory and antiviral effects of silymarin and quercetin mainly include immune modulation and inhibition of caspase enzymes, viral binding and replication, RNA synthesis, viral proteases and viral assembly. In the nutraceutical sector, natural flavonoids low bioavailability and solubility necessitate the application of delivery systems to enhance their efficacy. This review study provided an updated understanding of the protective role of quercetin and silymarin against viral-associated IBD.

CHARACTERISTICS OF THE BINDING BETWEEN THE ENZYME PREPARATION RAPHANUS SATIVUS L. AND NATURAL LAYERED ALUMOSILICA IN THE PRESENCE OF IRON OXIDES

IR and X-ray analyses of bentonite modified with magnetite and enzyme established the dependence of enzyme immobilization on the presence of iron oxides. IR studies have proven that the binding of the enzyme to the carrier is adsorption in nature without stable chemical interactions. This type of binding does not significantly affect the change in the structure of the enzyme module. Characte­ristic bands of vibrations of amide groups of proteins were detected at 1637 cm-1 ( ν-vibrations of C=O bonds (amide I)), 713 cm-1 (δ – vibrations of O=C-N in the plane (amide IV)), which can participate in the sorption binding of the enzyme to bentonite and the SiO2 group, which is characterized by a weak connection of the outer part of protein with the formation of a surface structure, which disappears over time due to the diffusion of molecules into the pores of the mineral. Comparison of the basal distances in the samples established the following dependence: 12.43 Å bentonite+ Fe3O4+enz (48 h) &gt; 12.38; Å natural bentoni­te&gt; 12.31; Å bentonite+ Fe3O4+enz (2 hours) &gt; 11.91; Å bentonite+ Fe3O4 , which indicates a high probability of iron compounds entering the interlayer space due to the hydrolysis of magnetite with the formation of Fe-(OH)n bonds and unstable compounds. According to the research results, a scheme of the interaction of the enzyme with modified layered iron aluminosilicate is proposed: 1 – transport of the enzyme to the surface (phase distribution boundaries); 2 – deformation of the enzyme under the action of the surface as a result of a polycondensation reaction with the formation of water molecules; 3 – entry of water molecules into the interlayer space; 4 – hydrolysis of magnetite particles; 5 – extraction of iron hydroxide from the interlayer space due to the formation of aggregates with an enzyme molecule that has a related adsorption center.

Enzymatic reaction modulated hydride generation of arsenic for parathion-methyl monitoring in traditional Chinese medicine by atomic fluorescence spectrometry

In the production of traditional Chinese medicine (TCM), the frequent use of organophosphorus pesticides (OPs) will lead to a certain residue and affect the quality of TCM. Therefore, the development of simple and rapid methods for OPs residue monitoring is of great significance for the quality control and evaluation of TCM. In this work, a novel method was developed for the indirect determination of parathion-methyl (PM) residue in TCM by hydride generation atomic fluorescence spectrometry (HG-AFS) based on enzyme modulation. The acetylthiocholine (ATCh) can be hydrolyzed by butyrylcholinesterase (BChE) to produce thiocholine (TCh), which contains − SH that can interact with As(III) and inhibits its HG procedure, further reducing its AFS signal. However, OPs like PM can inhibit the activity of BChE to restore the AFS signal. Therefore, the indirect analysis of PM can be achieved by detecting As(III). A low limit of detection (LOD) of 0.043 μg mL−1 and a relative standard deviation (RSD) of 0.5% were obtained, respectively. The proposed method was successfully applied for the analysis of PM residue in 6 kinds of TCMs commonly used in clinical practice. This present strategy offers a unique alternative for OPs assay with high sensitivity, selectivity, and simple operation.

Norbergenin prevents LPS-induced inflammatory responses in macrophages through inhibiting NFκB, MAPK and STAT3 activation and blocking metabolic reprogramming.

Inflammation is thought to be a key cause of many chronic diseases and cancer. However, current therapeutic agents to control inflammation have limited long-term use potential due to various side-effects. This study aimed to examine the preventive effects of norbergenin, a constituent of traditional anti-inflammatory recipes, on LPS-induced proinflammatory signaling in macrophages and elucidate the underlying mechanisms by integrative metabolomics and shotgun label-free quantitative proteomics platforms. Using high-resolution mass spectrometry, we identified and quantified nearly 3000 proteins across all samples in each dataset. To interpret these datasets, we exploited the differentially expressed proteins and conducted statistical analyses. Accordingly, we found that LPS-induced production of NO, IL1β, TNFα, IL6 and iNOS in macrophages was alleviated by norbergenin via suppressed activation of TLR2 mediated NFκB, MAPKs and STAT3 signaling pathways. In addition, norbergenin was capable of overcoming LPS-triggered metabolic reprogramming in macrophages and restrained the facilitated glycolysis, promoted OXPHOS, and restored the aberrant metabolites within the TCA cycle. This is linked to its modulation of metabolic enzymes to support its anti-inflammatory activity. Thus, our results uncover that norbergenin regulates inflammatory signaling cascades and metabolic reprogramming in LPS stimulated macrophages to exert its anti-inflammatory potential.

Modulation of enzymes and metabolites in response to shoot fly infestation in resistant and susceptible sorghum genotypes

Modulation of enzymes and metabolites in response to shoot fly infestation in resistant and susceptible sorghum genotypes

Feinabstimmung der Redoxeigenschaften von heteroleptischen Molybdän‐Komplexen mittels Ligand‐Ligand‐Kooperativität

AbstractHeteroleptische Molybdänkomplexe mit 1,5‐Diaza‐3,7‐Diphosphacyclooctan (P2N2) und non‐innocent (nicht‐unschuldigen) Dithiolenliganden wurden synthetisiert und elektrochemisch charakterisiert. Dabei wurde festgestellt, dass die Reduktionspotentiale der Komplexe durch einen synergistischen Effekt moduliert werden, welcher durch DFT‐Berechnungen als Ligand‐Ligand‐Kooperativität über nicht‐kovalente Wechselwirkungen identifiziert werden konnte. Dieses Ergebnis konnte durch elektrochemische Studien in Kombination mit UV/Vis‐Spektroskopie und temperaturabhängiger NMR‐Spektroskopie bestätigt werden. Das beobachtete Verhalten erinnert an eine enzymatische Redoxmodulation durch Effekte basierend auf Interaktionen in der zweiten Ligandensphäre.

Fine-Tuning Redox Properties of Heteroleptic Molybdenum Complexes through Ligand-Ligand-Cooperativity.

Heteroleptic molybdenum complexes bearing 1,5-diaza-3,7-diphosphacyclooctane (P2 N2 ) and non-innocent dithiolene ligands were synthesized and electrochemically characterized. The reduction potentials of the complexes were found to be fine-tuned by a synergistic effect identified by DFT calculations as ligand-ligand cooperativity via non-covalent interactions. This finding is supported by electrochemical studies combined with UV/Vis spectroscopy and temperature-dependent NMR spectroscopy. The observed behavior is reminiscent of enzymatic redox modulation using second ligand sphere effects.

Modulation of angiotensin converting enzyme 2 activity in human mesangial cells treated with hydroxychloroquine

Introduction: The occurrence of the first case caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the coronavirus disease (COVID-19), was described in Wuhan, China, by the end of 2019, and due to its high transmissibility, the virus had a fast dissemination throughout the world. One of COVID-19 complications is acute kidney injury. The SARS-CoV-2 possesses a membrane protein which interacts with a receptor on the host cell’s surface, the angiotensin converting enzyme 2 (ACE2), important for the virus internalization into the host cell. In the beginning of the pandemic, little was known about effective drugs against it, so hydroxychloroquine (HCQ) was indicated for both treatment or prophylactic measure against COVID-19, which is currently known for not having a protective action, and may affect the kidney depending on the concentration used. The kidney which is essential in maintaining the organism’s homeostasis through the renin-angiotensin-aldosterone system (RAAS), was also one of the main target organs in the COVID-19. The basic kidney unity, the nephron, possesses mesangial cells, which are part of both the glomerulus and the mesangial matrix, and synthetize some of the RAAS components. An imbalance in the RAAS may lead to arterial hypertension, one of the comorbidities that may cause the COVID-19 aggravation. Objectives: To evaluate the RAAS components modulation in immortalized human mesangial cells (IHMC) under treatment with hydroxychloroquine (HCQ), Losartan (Los) and the association of both medicines (Los+HCQ). Methods: The IHMC were treated for 4 hours with HCQ 50 μM or 150 μM, and Los 1 μM to evaluate the effects on ACE, ACE2 and renin activities. Protein quantification and cell viability with MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay were assessed by absorbance. ACE, ACE2 and renin proteolytic activities were evaluated by fluorometric assays using the substrates Z-Phe-His-Leu, APK(Dnp) and ABZ-DRVYIHPFHLVIHNQ-EDDnp, respectively. Results: Cell viability decreased after treatment with both drugs, either alone or combined. The renin activity showed no significant variation in the three groups studied. The ACE2 activity was lowered by Los, Los+HCQ, but not by HCQ alone. The expression of ACE2 detected by immunofluorescence presented no significant variation compared to the control. Conclusion: The decrease in ACE2 activity in all studied groups compared to the control, despite the protein synthesis remaining similar to the control, demonstrates that fragments of Angiotensins I and II can inhibit this activity. The ACE2 expression maintained similar levels despite treatments, which favors the SARS-CoV-2 infection process. The mechanisms involved in this process must be studied, considering that inhibiting the ACE2 activity implies in a decrease of Ang 1-7 production, compromising vasodilation. (Supported by CAPES and FAPESP This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Reactive Oxygen Species Metabolism Modulation on the Quality of Apple Fruits Inoculated with Penicillium expansum under Different Ambient pHs

Apple blue mold is a significant postharvest disease caused by Penicillium expansum. pH modification in colonized tissues leads to the production of organic substances, the modulation of enzymes, and then increases fungal pathogenicity. This study evaluated Penicillium expansum-inoculated apple fruits’ quality responding to pH treatments ranging from 2.5 to 8.5 and analyzed the reactive oxygen species (ROS) metabolism modulation in inoculated apple fruits at the same pH. The results showed that the fruit quality of the firmness, total soluble solids, and titratable acid displayed a quick loss at pHs 5.0 and 7.0, compared with 2.5 and 8.5. Similarly, higher disease incidence was observed at pHs 5.0 and 7.0. Apple fruits infected with P. expansum at pHs 2.5 and 8.5 had less content of O2•−, H2O2, and malondialdehyde (MDA); lower enzymatic activity of NADPH oxidase (NOX); and greater cell membrane integrity than those at pHs 5.0 and 7.0. The analysis of the antioxidant enzymatic activities showed upregulation of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) at pHs 2.5 and 8.5 compared with those at pHs 5.0 and 7.0. Similar trends were shown in ascorbic acid and glutathione. These results support the hypothesis that inoculated apple fruits at pHs 2.5 and 8.5 improve resistance to P. expansum by modulating ROS metabolism, compared with pHs 5.0 and 7.0.

Role of the Dietary Phytochemical Curcumin in Targeting Cancer Cell Signalling Pathways.

The diarylheptanoid curcumin [(1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione] is one of the phenolic pigments responsible for the yellow colour of turmeric (Curcuma longa L.). This phytochemical has gained much attention in recent years due to its therapeutic potential in cancer. A range of drug delivery approaches have been developed to optimise the pharmacokinetic profile of curcumin and ensure that it reaches its target sites. Curcumin exhibits numerous biological effects, including anti-inflammatory, cardioprotective, antidiabetic, and anti-aging activities. It has also been extensively studied for its role as a cancer chemopreventive and anticancer agent. This review focusses on the role of curcumin in targeting the cell signalling pathways involved in cancer, particularly via modulation of growth factors, transcription factors, kinases and other enzymes, pro-inflammatory cytokines, and pro-apoptotic and anti-apoptotic proteins. It is hoped that this study will help future work on the potential of curcumin to fight cancer.

Modulation of IRAK enzymes as a therapeutic strategy against SARS-CoV-2 induced cytokine storm.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the current pandemic coronavirus disease 2019 (COVID-19). Dysregulated and excessive production of cytokines and chemokines, known as cytokine storm, is frequently seen in patients with severe COVID-19 disease and it can provoke a severe systematic inflammation in the patients. The IL-1R/TLRs/IRAKs signaling network is a key pathway in immune cells that plays a central role in regulating innate immunity and inflammatory responses via stimulating the expression and production of various proinflammatory molecules including cytokines. Modulation of IRAKs activity has been proposed to be a promising strategy in the treatment of inflammatory disorders. In this review, we highlight the biochemical properties of IRAKs and their role in regulating inflammatory molecular signaling pathways and discuss the potential targeting of IRAKs to suppress the SARS-CoV-2-induced cytokine storm in COVID-19 patients.

A Hitchhiker's Guide to Supplying Enzymatic Reducing Power into Synthetic Cells.

The construction from scratch of synthetic cells by assembling molecular building blocks is unquestionably an ambitious goal from a scientific and technological point of view. To realize functional life-like systems, minimal enzymatic modules are required to sustain the processes underlying the out-of-equilibrium thermodynamic status hallmarking life, including the essential supply of energy in the form of electrons. The nicotinamide cofactors NAD(H) and NADP(H) are the main electron carriers fueling reductive redox reactions of the metabolic network of living cells. One way to ensure the continuous availability of reduced nicotinamide cofactors in a synthetic cell is to build a minimal enzymatic module that can oxidize an external electron donor and reduce NAD(P)+. In the diverse world of metabolism there is a plethora of potential electron donors and enzymes known from living organisms to provide reducing power to NAD(P)+ coenzymes. This perspective proposes guidelines to enable the reduction of nicotinamide cofactors enclosed in phospholipid vesicles, while avoiding high burdens of or cross-talk with other encapsulated metabolic modules. By determining key requirements, such as the feasibility of the reaction and transport of the electron donor into the cell-like compartment, we select a shortlist of potentially suitable electron donors. We review the most convenient proteins for the use of these reducing agents, highlighting their main biochemical and structural features. Noting that specificity toward either NAD(H) or NADP(H) imposes a limitation common to most of the analyzed enzymes, we discuss the need for specific enzymes─transhydrogenases─to overcome this potential bottleneck.

5-Aminolevulinic acid mitigates the chromium-induced changes in Helianthus annuus L. as revealed by plant defense system enhancement

Chromium (Cr) in the soil is one of the major pollutants for agricultural production. This study examined the efficiency of sunflower plants to remediate Cr-contaminated soils using a plant growth regulator, 5-aminolevolinic acid (ALA). At six leaf stage, sunflower plants were exposed to soil-applied Cr (0.15 g kg−1), manganese (Mn, 0.3 g kg−1) and trisodium (S,S)-ethylenediamine-N,N′-disuccinic acid (EDDS, 2.5 mmol kg−1), ALA (10 mg L−1) was sprayed. After ALA treatment, the plants were harvested for further biochemical analyses. Results showed that EDDS and Mn improved the Cr accumulation but restrained plant growth. Conversely, ALA improved the growth of Cr-stressed plants by promoting chlorophyll concentration in the top fully expanded leaves. The bioaccumulation quantity and removal efficiency of sunflowers treated by Cr + EDDS + ALA was improved by 47.92% and 47.94%, respectively, as compared to the Cr treatment. This was further supported by qRT-PCR analysis, where the expression of heavy metal transport genes such as ZIP6 and NRAMP6 and subsequently Cr accumulation in sunflower tissues increased by EDDS, Mn, and ALA application. However, compared with other treatments, ALA ameliorated cellular injury from Cr-stress by uptake or movement of Cr prevention, modulation of antioxidant enzymes, and elimination of reactive oxygen species. Our study suggested that ALA as an ideal option for the phytoremediation of Cr-contaminated soils.

FLOURY ENDOSPERM 6 mutations enhance the sugary phenotype caused by the loss of ISOAMYLASE1 in barley

Key messageBarley double mutants in two genes involved in starch granule morphology, HvFLO6 and HvISA1, had impaired starch accumulation and higher grain sugar levels than either single mutant.Starch is a biologically and commercially important glucose polymer synthesized by plants as semicrystalline starch granules (SGs). Because SG morphology affects starch properties, mutants with altered SG morphology may be useful in breeding crops with desirable starch properties, including potentially novel properties. In this study, we employed a simple screen for mutants with altered SG morphology in barley (Hordeum vulgare). We isolated mutants that formed compound SGs together with the normal simple SGs in the endosperm and found that they were allelic mutants of the starch biosynthesis genes ISOAMYLASE1 (HvISA1) and FLOURY ENDOSPERM 6 (HvFLO6), encoding starch debranching enzyme and CARBOHYDRATE-BINDING MODULE 48-containing protein, respectively. We generated the hvflo6 hvisa1 double mutant and showed that it had significantly reduced starch biosynthesis and developed shrunken grains. In contrast to starch, soluble α-glucan, phytoglycogen, and sugars accumulated to higher levels in the double mutant than in the single mutants. In addition, the double mutants showed defects in SG morphology in the endosperm and in the pollen. This novel genetic interaction suggests that hvflo6 acts as an enhancer of the sugary phenotype caused by hvisa1 mutation.

Enzymatic Synthesis of Sialyl Lactosamine Grafted Chitooligosaccharides

Comprehensive SummaryAn efficient enzymatic assembly strategy was developed for the concise synthesis of structurally well‐defined sialylated chitooligosaccharides. Two enzyme modules for the β‐1,3‐N‐acetyl‐glucosaminylation and β‐1,4‐galactosylation were applied for the grafting N‐acetyl lactosamine (LacNAc) unit(s) onto the chitooligosaccharides. The LacNAc grafted chitooligosaccharides were further modified with α‐2,3‐ or α‐2,6‐sialylation by two enzymatic sialylation modules to generate a total of 20 sialylated chitooligosaccharides. The inhibition study of influenza virus‐induced cytopathy with synthetic sialylated chitooligosaccharides indicated that the sialic acid linkage and chain length both contribute to the binding preference and inhibition potency.