Subunit Composition Research Articles

Pseudomonas aeruginosa Bacterioferritin Is Assembled from FtnA and BfrB Subunits with the Relative Proportions Dependent on the Environmental Oxygen Availability.

Ferritins are iron storage proteins assembled from 24 subunits into a spherical and hollow structure. The genomes of many bacteria harbor genes encoding two types of ferritin-like proteins, the bacterial ferritins (Ftn) and the bacterioferritins (Bfr), which bind heme. The genome of P. aeruginosa PAO1 (like the genomes of many bacteria) contains genes coding for two different types of ferritin-like molecules, ftnA (PA4235) and bfrB (PA3531). The reasons for requiring the presence of two distinct types of iron storage protein in bacterial cells have remained largely unexplained. Attempts to understand this issue in P. aeruginosa through the recombinant expression of the ftnA and bfrB genes in E. coli host cells, coupled to the biochemical and structural characterization of the recombinant 24-mer FtnA and 24-mer BfrB molecules, have shown that each of the recombinant molecules can form an Fe3+-mineral core. These observations led to the suggestion that 24-mer FtnA and 24-mer BfrB molecules coexist in P. aeruginosa cells where they share iron storage responsibilities. Herein, we demonstrate that P. aeruginosa utilizes a single heterooligomeric 24-mer Bfr assembled from FtnA and BfrB subunits. The relative content of the FtnA and BfrB subunits in Bfr depends on the O2 availability during cell culture, such that Bfr isolated from aerobically cultured P. aeruginosa is assembled from a majority of BfrB subunits. In contrast, when the cells are cultured in O2-limiting conditions, the proportion of FtnA subunits in the isolated Bfr increases significantly and can become the most abundant subunit. Despite the variability in the subunit composition of Bfr, the 24-mer assembly is consistently arranged from FtnA subunit dimers devoid of heme and BfrB subunit dimers each containing a heme molecule.

Tailoring protein intrinsic charge by enzymatic deamidation for solubilizing chicken breast myofibrillar protein in water

Inspired by the salt-in effect, the potential use of protein-glutaminase (PG) to increase the intrinsic charges of chicken breast myofibrillar proteins (CMPs) for enhanced water solubility was tested. The degree of deamidation (DD) and solubility of CMPs increased with PG reaction time. Over 60% of CMPs were soluble in water under a DD of 6.5% due to specific conversion of glutamine to glutamic acid. PG deamidation could remarkably increase the net charge of CMPs with a merit in maintaining most of the amino acid and protein subunit compositions. Such a high electrostatic repulsion exerted a transformation of β-sheet into α-helix, unfolded the structure to expose hydrophobic residues, and allowed the dissociation of myofibril and release of subunits (myosin, actin or their oligomers), leading to a stable colloidal state. This work may foster the engineering advances of protein micro-modification in the tailor manufacture of muscle protein-based beverages.

Extrasynaptic NMDA Receptors Bidirectionally Modulate Intrinsic Excitability of Inhibitory Neurons.

The NMDA subtype glutamate receptors (NMDARs) play important roles in both physiological and pathologic processes in the brain. Compared with their critical roles in synaptic modifications and excitotoxicity in excitatory neurons, much less is understood about the functional contributions of NMDARs to the inhibitory GABAergic neurons. By using selective NMDAR inhibitors and potentiators, we here show that NMDARs bidirectionally modulate the intrinsic excitability (defined as spontaneous/evoked spiking activity and EPSP-spike coupling) in inhibitory GABAergic neurons in adult male and female mice. This modulation depends on GluN2C/2D- but not GluN2A/2B-containing NMDARs. We further show that NMDAR modulator EU1794-4 mostly enhances extrasynaptic NMDAR activity, and by using it we demonstrate a significant contribution of extrasynaptic NMDARs to the modulation of intrinsic excitability in inhibitory neurons. Together, this bidirectional modulation of intrinsic excitability reveals a previously less appreciated importance of NMDARs in the second-to-second functioning of inhibitory GABAergic neurons.SIGNIFICANCE STATEMENT NMDA subtype of glutamate receptors (NMDARs) have important roles in brain functions, including both physiological and pathologic ones. The role of NMDARs in inhibitory neurons has been less elucidated compared with that in excitatory neurons. Our results demonstrate the importance of GluN2C/GluN2D-containing but not GluN2A/GluN2B-containing extrasynaptic NMDARs in modulating the intrinsic excitability of inhibitory neurons. These results further suggest distinct contributions of subsynaptic locations and subunit compositions of NMDARs to their functions in excitatory and inhibitory neurons. The above findings have implications for better understanding of brain diseases, such as schizophrenia.

Identification and biochemical characterization of a heteromeric cis-prenyltransferase from the thermophilic archaeon Archaeoglobus fulgidus.

cis-Prenyltransferases (cPTs) form linear polyprenyl pyrophosphates, the precursors of polyprenyl or dolichyl phosphates that are essential for cell function in all living organisms. Polyprenyl phosphate serves as a sugar carrier for peptidoglycan cell wall synthesis in bacteria, a role that dolichyl phosphate performs analogously for protein glycosylation in eukaryotes and archaea. Bacterial cPTs are characterized by their homodimeric structure, while cPTs from eukaryotes usually require two distantly homologous subunits for enzymatic activity. This study identifies the subunits of heteromeric cPT, Af1219 and Af0707, from a thermophilic sulphur-reducing archaeon, Archaeoglobus fulgidus. Both subunits are indispensable for cPT activity, and their protein-protein interactions were demonstrated by a pulldown assay. Gel filtration chromatography and chemical cross-linking experiments suggest that Af1219 and Af0707 likely form a heterotetramer complex. Although this expected subunit composition agrees with a reported heterotetrameric structure of human hCIT/NgBR cPT complex, the similarity of the quaternary structures is likely a result of convergent evolution.

Repetitive mild traumatic brain injury induces persistent alterations in spontaneous synaptic activity of hippocampal CA1 pyramidal neurons.

Mild traumatic brain injury (mTBI) or concussion is the most common form of TBI which frequently results in persistent cognitive impairments and memory deficits in affected individuals [1]. Although most studies have investigated the role of hippocampal synaptic dysfunction in earlier time points following a single injury, the long-lasting effects of mTBI on hippocampal synaptic transmission following multiple brain concussions have not been well-elucidated. Using a repetitive closed head injury (3XCHI) mouse model of mTBI, we examined the alteration of spontaneous synaptic transmission onto hippocampal CA1 pyramidal neurons by recording spontaneous excitatory AMPA receptor (AMPAR)- and inhibitory GABAAR-mediated postsynaptic currents (sEPSCs and sIPSCs, respectively) in adult male mice 2-weeks following the injury. We found that mTBI potentiated postsynaptic excitatory AMPAR synaptic function while depressed postsynaptic inhibitory GABAAR synaptic function in CA1 pyramidal neurons. Additionally, mTBI slowed the decay time of AMPAR currents while shortened the decay time of GABAAR currents suggesting changes in AMPAR and GABAAR subunit composition by mTBI. On the other hand, mTBI reduced the frequency of sEPSCs while enhanced the frequency of sIPSCs resulting in a lower ratio of sEPSC/sIPSC frequency in CA1 pyramidal neurons of mTBI animals compared to sham animals. Altogether, our results suggest that mTBI induces persistent postsynaptic modifications in AMPAR and GABAAR function and their synaptic composition in CA1 neurons while triggering a compensatory shift in excitation/inhibition (E/I) balance of presynaptic drives towards more inhibitory synaptic drive to hippocampal CA1 cells. The persistent mTBI-induced CA1 synaptic dysfunction and E/I imbalance could contribute to deficits in hippocampal plasticity that underlies long-term hippocampal-dependent learning and memory deficits in mTBI patients long after the initial injury.

Opportunities for Precision Treatment of GRIN2A and GRIN2B Gain-of-Function Variants in Triheteromeric N-Methyl-D-Aspartate Receptors.

N-methyl-D-aspartate receptors (NMDARs) are tetrameric assemblies of two glutamate N-methyl-D-aspartate receptor subunits, GluN1 and two GluN2, that mediate excitatory synaptic transmission in the central nervous system. Four genes (GRIN2A-D) encode four distinct GluN2 subunits (GluN2A-D). Thus, NMDARs can be diheteromeric assemblies of two GluN1 plus two identical GluN2 subunits, or triheteromeric assemblies of two GluN1 subunits plus two different GluN2 subunits. An increasing number of de novo GRIN variants have been identified in patients with neurologic conditions and with GRIN2A and GRIN2B harboring the vast majority (> 80%) of variants in these cases. These variants produce a wide range of effects on NMDAR function depending upon its subunit subdomain location and additionally on the subunit composition of diheteromeric versus triheteromeric NMDARs. Increasing evidence implicates triheteromeric GluN1/GluN2A/GluN2B receptors as a major component of the NMDAR pool in the adult cortex and hippocampus. Here, we explore the ability of GluN2A- and GluN2B-selective inhibitors to reduce excess current flow through triheteromeric GluN1/GluN2A/GluN2B receptors that contain one copy of GRIN2A or GRIN2B gain-of-function variants. Our data reveal a broad range of sensitivities for variant-containing triheteromeric receptors to subunit-selective inhibitors, with some variants still showing strong sensitivity to inhibitors, whereas others are relatively insensitive. Most variants, however, retain sensitivity to non-selective channel blockers and the competitive antagonist D-(-)-2-amino-5-phosphonopentanoic acid. These results suggest that with comprehensive analysis, certain disease-related GRIN2A and GRIN2B variants can be identified as potential targets for subunit-selective modulation and potential therapeutic gain. SIGNIFICANCE STATEMENT: Triheteromeric NMDA receptors that contain one copy each of the GluN2A and GluN2B subunits show intermediate sensitivity to GluN2A- and GluN2B-selective inhibitors, making these compounds candidates for attenuating overactive, GRIN variant-containing NMDA receptors associated with neurological conditions. We show that functional evaluation of variant properties with inhibitor pharmacology can support selection of a subset of variants for which GluN2 subunit-selective agents remain effective inhibitors of variant-containing triheteromeric NMDA receptors.

Purification and Identification of the 20S Proteasome Complex from Zebrafish.

The proteasome is a large polymeric protease complex responsible for degradation of intracellular proteins and generation of peptides. In this study, we purified a native 20S proteasome protein complex from zebrafish (Danio rerio) from the whole body. The cytosolic fraction of zebrafish hydrolyzed Suc-Leu-Leu-Val-Tyr-MCA (Suc-LLVY-MCA), a well-known substrate for the proteasome, in the presence of sodium dodecyl sulfate. From the cytosolic fraction, the 20S proteasome was purified using five column chromatography steps: DEAE cellulose, Q-Sepharose, Sephacryl S-300 gel, hydroxylapatite, and phenyl Sepharose. Electrophoresis and Western blot analyses showed that zebrafish 20S proteasome subunits have molecular masses ranging from 22 to 33 kDa. The subunit composition of the purified 20S proteasome was identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis after two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) separation. Fourteen kinds of 20S subunits were found. As a special characteristic of zebrafish, two proteins of the α1 subunit were identified. In addition, the results suggested that the α8 subunit is in the 20S complex instead of the α4 subunit. In this study, we demonstrated the subunit composition of the 20S proteasome complex present in zebrafish cells.

Nicotinic acetylcholine receptor modulator insecticides act on diverse receptor subtypes with distinct subunit compositions.

Insect nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels mainly expressed in the central nervous system of insects. They are the directed targets of many insecticides, including neonicotinoids, which are the most widely used insecticides in the world. However, the development of resistance in pests and the negative impacts on bee pollinators affect the application of insecticides and have created a demand for alternatives. Thus, it is very important to understand the mode of action of these insecticides, which is not fully understood at the molecular level. In this study, we systematically examined the susceptibility of ten Drosophila melanogaster nAChR subunit mutants to eleven insecticides acting on nAChRs. Our results showed that there are several subtypes of nAChRs with distinct subunit compositions that are responsible for the toxicity of different insecticides. At least three of them are the major molecular targets of seven structurally similar neonicotinoids in vivo. Moreover, spinosyns may act exclusively on the α6 homomeric pentamers but not any other nAChRs. Behavioral assays using thermogenetic tools further confirmed the bioassay results and supported the idea that receptor activation rather than inhibition leads to the insecticidal effects of neonicotinoids. The present findings reveal native nAChR subunit interactions with various insecticides and have important implications for the management of resistance and the development of novel insecticides targeting these important ion channels.

Developmental Formation of the GABAergic and Glycinergic Networks in the Mouse Spinal Cord.

Gamma-aminobutyric acid (GABA) and glycine act as inhibitory neurotransmitters. Three types of inhibitory neurons and terminals, GABAergic, GABA/glycine coreleasing, and glycinergic, are orchestrated in the spinal cord neural circuits and play critical roles in regulating pain, locomotive movement, and respiratory rhythms. In this study, we first describe GABAergic and glycinergic transmission and inhibitory networks, consisting of three types of terminals in the mature mouse spinal cord. Second, we describe the developmental formation of GABAergic and glycinergic networks, with a specific focus on the differentiation of neurons, formation of synapses, maturation of removal systems, and changes in their action. GABAergic and glycinergic neurons are derived from the same domains of the ventricular zone. Initially, GABAergic neurons are differentiated, and their axons form synapses. Some of these neurons remain GABAergic in lamina I and II. Many GABAergic neurons convert to a coreleasing state. The coreleasing neurons and terminals remain in the dorsal horn, whereas many ultimately become glycinergic in the ventral horn. During the development of terminals and the transformation from radial glia to astrocytes, GABA and glycine receptor subunit compositions markedly change, removal systems mature, and GABAergic and glycinergic action shifts from excitatory to inhibitory.

Progresses in GluN2A-containing NMDA Receptors and their Selective Regulators.

NMDA receptors play an important physiological role in regulating synaptic plasticity, learning and memory. GluN2A subunits are the most abundant functional subunits of NMDA receptors expressed in mature brain, and their dysfunction is related to various neurological diseases. According to subunit composition, GluN2A-containing NMDA receptors can be divided into two types: diheteromeric and triheteromeric receptors. In this review, the expression, functional and pharmacological properties of different kinds of GluN2A-containing NMDA receptors as well as selective GluN2A regulators were described to further understand this type of NMDA receptors.

ECMpy, a Simplified Workflow for Constructing Enzymatic Constrained Metabolic Network Model.

Genome-scale metabolic models (GEMs) have been widely used for the phenotypic prediction of microorganisms. However, the lack of other constraints in the stoichiometric model often leads to a large metabolic solution space being inaccessible. Inspired by previous studies that take an allocation of macromolecule resources into account, we developed a simplified Python-based workflow for constructing enzymatic constrained metabolic network model (ECMpy) and constructed an enzyme-constrained model for Escherichia coli (eciML1515) by directly adding a total enzyme amount constraint in the latest version of GEM for E. coli (iML1515), considering the protein subunit composition in the reaction, and automated calibration of enzyme kinetic parameters. Using eciML1515, we predicted the overflow metabolism of E. coli and revealed that redox balance was the key reason for the difference between E. coli and Saccharomyces cerevisiae in overflow metabolism. The growth rate predictions on 24 single-carbon sources were improved significantly when compared with other enzyme-constrained models of E. coli. Finally, we revealed the tradeoff between enzyme usage efficiency and biomass yield by exploring the metabolic behaviours under different substrate consumption rates. Enzyme-constrained models can improve simulation accuracy and thus can predict cellular phenotypes under various genetic perturbations more precisely, providing reliable guidance for metabolic engineering.

Purification, characterization, and immunomodulatory activity of a lectin from the seeds of horse chestnut (Aesculus hippocastanum L.)

This work aimed to purify, characterize, and evaluate the immunomodulatory activity of a lectin from Aesculus hippocastanum seeds (AhSL). The lectin was isolated from saline extract through chromatography on a DEAE-Sephadex column. Protein homogeneity and subunit composition were evaluated with polyacrylamide gel electrophoresis (PAGE) under native and denaturing (SDS-PAGE) conditions, respectively. AhSL was evaluated for trypsin inhibitor activity, carbohydrate-binding specificity, and the effects of cations (Ca2+, Mn2+, and Mg2+), temperature, and pH on its hemagglutinating activity. Lectin stability under heating and pH variation was evaluated through fluorometric analysis. The activity of this lectin (12.5 µg/mL) in modulating cytokine release and nitric oxide production by mouse splenocytes was assessed. Isolated AhSL (purification fold: 68.8) showed a single polypeptide band in PAGE for acidic proteins and two polypeptide bands of approximately 68 and 124 kDa in SDS-PAGE. Its hemagglutinating activity was inhibited by monosaccharides, disaccharides, and glycoproteins, but was not affected by cations, and remained stable after heating (30–100 °C) and under pH 4.0–8.0. Fluorometric analysis revealed that the overall lectin conformation was not altered after heating to 100 °C and remained stable under various pH values. AhSL also showed trypsin inhibitor activity (specific activity: 1,280.31 U/mg) and induced the release of interleukins 10 and 6, tumor necrosis factor α, and nitric oxide by splenocytes. In conclusion, AhSL is a bioactive protein with promising biotechnological potential, which may find applications as immunological targeting or antitumor agents.

Something's fishy: cardiovascular ATP-sensitive K+ channels in zebrafish.

Mammalian adenosine-triphosphate-sensitive K+ (KATP ) channels help couple cellular metabolism to electrical excitability in cardiac myocytes and are activated and inhibited by vasodilators and vasoconstrictors, respectively, in vascular myocytes. Using a combination of patch-clamp electrophysiology along with knockout and knockin strategies the subunit composition of zebrafish cardiovascular KATP channels were shown to be similar to the mammalian orthologs. However, zebrafish KATP channels were insensitive to small molecule KATP channel openers. These findings suggest that zebrafish may be an appropriate model system to study the cardiovascular sequelae of KATP channelopathies and molecular comparisons between mammalian and zebrafish KATP orthologs may help define the binding sites for KATP channel openers in the future. This article is protected by copyright. All rights reserved.

NACHO permits functional heterologous expression of an insect homomeric α6 nicotinic acetylcholine receptor

Insect nicotinic acetylcholine receptors (nAChR) are molecular targets of highly effective insecticides. The use of chaperone proteins has been key to successful functional expression of these receptors in heterologous systems, permitting functional and pharmacological studies of insect nAChRs with particular subunit composition. Here, we report the first use of the chaperone protein, NACHO, to enable functional expression of an insect nAChR, the α6 subunit from Apis mellifera, in Xenopus laevis oocytes. This is also the first report of functional expression of a homomeric insect α6 nAChR. Using two-electrode voltage-clamp electrophysiology we show that the acetylcholine EC50 of the α6 receptor is 0.88 μM and that acetylcholine responses are antagonized by α-bungarotoxin. Spinosad showed agonist actions and kept the ion channel open when co-applied with acetylcholine, reinforcing the α6 nAChR subunit as a key molecular target for the spinosyn class of insecticide. The use of NACHO may provide a basis for future expression studies of insect α6 nAChRs, potentially providing a tool for the discovery of novel insecticides.

Biophysical and synaptic properties of regular spiking interneurons in hippocampal area CA3 of aged rats

Neuronal processing from the dentate gyrus to the hippocampus is critical for storage and recovery of new memory traces. In area CA3, GABAergic interneurons form a strong barrage of inhibition that modulates pyramidal cells. A well-established feature of aging is decreased GABAergic inhibition, a phenomenon that contributes to the exacerbated excitability of aged pyramidal cells. In hippocampal slices of aged rats (22–28 months old) we examined the properties of regular spiking CA3 interneurons with patch-clamp whole-cell recordings. We found enhanced firing discharge without altering the maximal firing rate of aged regular spiking interneurons. In the mossy fibers (MF) to interneurons synapse, a switch in the AMPA receptor subunit composition was found in aged interneurons. Young regular spiking interneurons predominantly express CP AMPA receptors and MF LTD. By contrast, aged regular spiking interneurons contain a higher proportion of CI AMPA receptors and respond with MF LTP. We show for the first time that the specialized MF terminals contacting interneurons, retain synaptic capabilities and provide a novel insight of the interneuron's function during aging.

Pharmacological characterization of novel heteromeric GluCl subtypes from Caenorhabditis elegans and parasitic nematodes.

Background and PurposeMacrocyclic lactones are the most widely used broad‐spectrum anthelmintic drugs for the treatment of parasitic nematodes affecting both human and animal health. Macrocyclic lactones are agonists of the nematode glutamate‐gated chloride channels (GluCls). However, for many important nematode species, the GluCls subunit composition and pharmacological properties remain largely unknown. To gain new insights into GluCl diversity and mode of action of macrocyclic lactones, we identified and pharmacologically characterized receptors made of highly conserved GluCl subunits from the model nematode Caenorhabditis elegans , the human filarial nematode Brugia malayi and the horse parasite Parascaris univalens.Experimental ApproachAVR‐14, GLC‐2, GLC3 and GLC‐4 are the most conserved GluCl subunits throughout the Nematoda phylum. For each nematode species, we investigated the ability of these subunits to form either homomeric or heteromeric GluCls when expressed in Xenopus laevis oocytes and carried out detailed pharmacological characterization of the functional channels.Key ResultsA total of 14 GluCls were functionally reconstituted, and heteromers formation was inferred from pharmacological criteria. The GLC‐2 subunit plays a pivotal role in the composition of heteromeric GluCls in nematodes. We also found a novel GluCl subtype, combining GLC‐2/GLC‐3 subunits, for which a high concentration of the anthelmintics ivermectin and moxidectin reversibly potentiates glutamate‐induced response.Conclusion and ImplicationsThis study brings new insights into the diversity of GluCl subtypes in nematodes and promotes novel drug targets for the development of the next generation of anthelmintic compounds.

Tosoh reports on its consolidated results for 1H FY 2022: Speciality Group

Depletion of intracellular calcium ion stores initiates a rapid cascade of events culminating with the activation of the so-called Store-Operated Channels (SOC) at the plasma membrane. Calcium influx via SOC is essential in the initiation of calcium-dependent intracellular signaling and for the refilling of internal calcium stores, ensuring the regeneration of the signaling cascade. In spite of the significance of this evolutionary conserved mechanism, the molecular identity of SOC has been the center of a heated controversy spanning over the last 20 years. Initial studies positioned some members of the transient receptor potential canonical (TRPC) channel superfamily of channels (with the more robust evidence pointing to TRPC1) as a putative SOC. Recent evidence indicates that Stromal Interacting Molecule 1 (STIM1) activates some members from the TRPC family of channels. However, the exact subunit composition of TRPC channels remains undetermined to this date. To identify the subunit composition of STIM1-activated TRPC channels, we developed novel method, which combines single channel electrophysiological measurements based on the patch clamp technique with single molecule fluorescence imaging. We termed this method Single ion Channel Single Molecule Detection technique (SC-SMD). Using SC-SMD method, we have obtained direct evidence of the subunit composition of TRPC channels activated by STIM1. Furthermore, our electrophysiological-imaging SC-SMD method provides evidence at the molecular level of the mechanism by which STIM1 and calmodulin antagonize to modulate TRPC channel activity.

Proteins and polysaccharides from vegetative mycelium of medicinal basidiomycete Lentinus edodes display cytotoxicity towards human and animal cancer cell lines

Detection and study of biologically active compounds seems a promising area of research in cancer diagnostics and therapies. The glycoprotein and polysaccharide fractions showing high cytotoxicity towards several human and animal cancer cell lines: A549, Hep-2, HeLa, С6 and SPEV-2 were isolated from basidiomycete Lentinus edodes vegetative mycelium and fruiting body and further characterized. It was found that water-soluble glycoprotein fractions caused the most significant, 70–100% inhibition of metabolic activity of SPЕV-2, А549 and С6 cell lines. The effective concentrations of glycoprotein fractions reducing the viability of cancer cell lines were determined. The protein and subunit composition of fractions was studied; the highly active galactose-specific lectins were found to be present in these fractions. Comparative analysis of transcriptomes of L. edodes vegetative mycelium, fruiting body and primordium revealed the presence of carbohydrate-binding glycoproteins (lectins) specific for each stage of basidiomycete morphogenesis. Histological examination revealed some morphological indicators of immune system activation and the absence of toxic effect on gastro-intestinal mucosa of animals at peroral administration of fungal glycoprotein fractions. Fungal protein and, in particular, lectin preparations derived from L. еdodes vegetative mycelium might be considered as novel prospective tools in cancer diagnostics and therapies.

Functions and Composition Variations of Wheat Glutenin Proteins in Steamed Bread and Noodles

As a major food crop, wheat offers indispensable energy and nutrients to humans worldwide. With the living standards rising, the demand of high-quality wheat increases sharply. Wheat gluten proteins (glutenins and gliadins) are important components of seed storage proteins that affect the elasticity, strength or viscosity of dough. In this review, we summarize the composition of glutenin subunits in wheat grain and analyze the impact of glutenin on the traditional Chinese foods: steamed bread and noodles. Furthermore, we summarize the molecular markers used for wheat quality breeding. The advent of the recent wheat genomic will speed up the identification and quality breeding of novel glutenins.

The avermectin/milbemycin receptors of parasitic nematodes

Glutamate-gated chloride channels are the most important target of ivermectin and related compounds in parasitic nematodes. A small family of genes encode subunits of these channels, allowing the assembly of multiple channel subtypes; the subunit composition of most of the native receptors is unknown. The members of the gene family vary between species, making extrapolation from C. elegans to parasites difficult. Expression of recombinant receptors in Xenopus oocytes can identify subunits that have the ability to co-assemble into novel channels, but localisation data, ideally at the single-cell level, is required to confirm that these subunits are expressed in the same cells and tissues. Fortunately, recent advances in this area are starting to make this information available; this information is adding to our understanding of how the drugs act and of the possible subunit combinations that create their targets in vivo.