• Cellular mechanisms governing glucose-dependent insulinotropic polypeptide secretion.

      Reimann, Frank; Diakogiannaki, Eleftheria; Moss, Catherine E.; Gribble, Fiona M.; Wellcome Trust; University of Cambridge (Elsevier, 2020-11-19)
      Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone secreted from the upper small intestine, which plays an important physiological role in the control of glucose metabolism through its incretin action to enhance glucose-dependent insulin secretion. GIP has also been implicated in postprandial lipid homeostasis. GIP is secreted from enteroendocrine K-cells residing in the intestinal epithelium. K-cells sense a variety of components found in the gut lumen following food consumption, resulting in an increase in plasma GIP signal dependent on the nature and quantity of ingested nutrients. We review the evidence for an important role of sodium-coupled glucose uptake through SGLT1 for carbohydrate sensing, of free-fatty acid receptors FFAR1/FFAR4 and the monoacyl-glycerol sensing receptor GPR119 for lipid detection, of the calcium-sensing receptor CASR and GPR142 for protein sensing, and additional modulation by neurotransmitters such as somatostatin and galanin. These pathways have been identified through combinations of in vivo, in vitro and molecular approaches.
    • Confocal microscopy provides visual evidence and confirms the feasibility of dsRNA delivery to emerald ash borer through plant tissues

      Pampolini, Flavia; Rodrigues, Thais B.; Leelash, Ramya S.; Kawashima, Tomokazu; Rieske, Lynne K. (Springer, 2020-05-15)
      Double-stranded RNA (dsRNA)-mediated gene silencing, or RNA interference (RNAi), is an emerging biotechnology that has been a breakthrough tool for crop protection. Exogenous dsRNA triggers the RNAi pathway, silences genes, disrupts protein function, and can cause insect mortality. However, effective delivery of the dsRNA is problematic, particularly in systems with long-lived, endophagous insects such as the emerald ash borer (EAB), Agrilus planipennis, a tree-killing nonnative invader that attacks ash, Fraxinus spp. Larvae feed on cambial tissue causing rapid tree death. EAB is susceptible to RNAi, but we lack a practical means of delivery. Here we evaluated delivery of dsRNA to green, F. pennsylvanica, and tropical ash, F. uhdei, through root and/or petiole absorption, and also demonstrated dsRNA absorption through the EAB egg chorion. We labeled exogenous dsRNA using a fluorescing label and then used confocal microscopy and RT-qPCR to evaluate its distribution in plant and insect tissues. Labeled dsRNAs are detectable in root, stem, and leaf tissues 48-h postapplication. In excised ash branches, labeled dsRNA is detectable in the inner bark and in recovered EAB neonates 8-day postapplication. Eggs and larvae emerging from treated eggs also presented fluorescing dsRNA under confocal imaging. Adult EAB-fed tropical ash leaves treated with in vitro synthesized EAB-specific dsSHI through petiole absorption experience a significant knockdown of the shi gene and a significant mortality. Our findings provide a proof of concept that delivery of dsRNAs through topical or systemic application methods is a feasible means of suppressing EAB, providing hope for future tree protection.
    • Risk prediction and assessment: duration, infections, and death toll of the COVID-19 and its impact on China’s economy

      Yue, Xiao-Guang; Shao, Xue-Feng; Li, Rita Yi Man; Crabbe, M. James C.; Mi, Lili; Hu, Siyan; Baker, Julien S.; Liu, Liting; Dong, Kechen; University of Bedfordshire; et al. (MDPI, 2020-04-03)
      This study first analyzes the national and global infection status of the Coronavirus Disease that emerged in 2019 (COVID-19). It then uses the trend comparison method to predict the inflection point and Key Point of the COVID-19 virus by comparison with the severe acute respiratory syndrome (SARS) graphs, followed by using the Autoregressive Integrated Moving Average model, Autoregressive Moving Average model, Seasonal Autoregressive Integrated Moving-Average with Exogenous Regressors, and Holt Winter’s Exponential Smoothing to predict infections, deaths, and GDP in China. Finally, it discusses and assesses the impact of these results. This study argues that even if the risks and impacts of the epidemic are significant, China’s economy will continue to maintain steady development.
    • Reconstructing phylogenetic relationships based on repeat sequence similarities

      Vitales, Daniel; Garcia, Sonia; Dodsworth, Steven; Institut Botànic de Barcelona; Universitat de Barcelona; University of Bedfordshire (Elsevier, 2020-02-28)
      A recent phylogenetic method based on genome-wide abundance of different repeat types proved to be useful in reconstructing the evolutionary history of several plant and animal groups. Here, we demonstrate that an alternative information source from the repeatome can also be employed to infer phylogenetic relationships among taxa. Specifically, this novel approach makes use of the repeat sequence similarity matrices obtained from the comparative clustering analyses of RepeatExplorer 2, which are subsequently transformed to between-taxa distance matrices. These pairwise matrices are used to construct neighbour-joining trees for each of the top most-abundant clusters and they are finally summarized in a consensus network. This methodology was tested on three groups of angiosperms and one group of insects, resulting in congruent evolutionary hypotheses compared to more standard systematic analyses based on commonly used DNA markers. We propose that the combined application of these phylogenetic approaches based on repeat abundances and repeat sequence similarities could be helpful to understand mechanisms governing genome and repeatome evolution.
    • Repetitive DNA restructuring across multiple Nicotiana allopolyploidisation events shows a lack of strong cytoplasmic bias in influencing repeat turnover

      Dodsworth, Steven; Guignard, Maite S.; Pérez-Escobar, Oscar A.; Struebig, Monika; Chase, Mark W.; Leitch, Andrew R.; ; University of Bedfordshire; Queen Mary University of London; Royal Botanic Gardens, Kew; et al. (MDPI, 2020-02-19)
      Allopolyploidy is acknowledged as an important force in plant evolution. Frequent allopolyploidy in Nicotiana across different timescales permits the evaluation of genome restructuring and repeat dynamics through time. Here we use a clustering approach on high-throughput sequence reads to identify the main classes of repetitive elements following three allotetraploid events, and how these are inherited from the closest extant relatives of the maternal and paternal subgenome donors. In all three cases, there was a lack of clear maternal, cytoplasmic bias in repeat evolution, i.e., lack of a predicted bias towards maternal subgenome-derived repeats, with roughly equal contributions from both parental subgenomes. Different overall repeat dynamics were found across timescales of <0.5 (N. rustica L.), 4 (N. repanda Willd.) and 6 (N. benthamiana Domin) Ma, with nearly additive, genome upsizing, and genome downsizing, respectively. Lower copy repeats were inherited in similar abundance to the parental subgenomes, whereas higher copy repeats contributed the most to genome size change in N. repanda and N. benthamiana. Genome downsizing post-polyploidisation may be a general long-term trend across angiosperms, but at more recent timescales there is species-specific variance as found in Nicotiana.
    • Risk management analysis for novel Coronavirus in Wuhan, China

      Yue, Xiao-Guang; Shao, Xue-Feng; Li, Rita Yi Man; Crabbe, M. James C.; Mi, Lili; Hu, Siyan; Baker, Julien S.; Liang, Gang; European University Cyprus; Polytechnic Institute of Porto; et al. (MDPI, 2020-02-03)
      Recently, a novel coronavirus pneumonia (2019–nCoV) outbreak occurred in Wuhan, China, rapidly spreading first to the whole country, and then globally, causing widespread concern. From the perspectives of early warning and identification of risk, risk monitoring, and analysis, as well as risk management and handling, we propose corresponding solutions and recommendations, which include institutional cooperation, and to inform national and international policy-makers.
    • Genomics evolutionary history and diagnostics of the Alternaria alternata species group including apple and Asian pear pathotypes

      Armitage, Andrew D.; Cockerton, Helen M.; Sreenivasaprasad, Surapareddy; Woodhall, James; Lane, Charles R.; Harrison, Richard; Clarkson, John P. (Frontiers, 2020-01-23)
      The Alternaria section alternaria (Alternaria alternata species group) represents a diverse group of saprotroph, human allergens, and plant pathogens. Alternaria taxonomy has benefited from recent phylogenetic revision but the basis of differentiation between major phylogenetic clades within the group is not yet understood. Furthermore, genomic resources have been limited for the study of host-specific pathotypes. We report near complete genomes of the apple and Asian pear pathotypes as well as draft assemblies for a further 10 isolates representing Alternaria tenuissima and Alternaria arborescens lineages. These assemblies provide the first insights into differentiation of these taxa as well as allowing the description of effector and non-effector profiles of apple and pear conditionally dispensable chromosomes (CDCs). We define the phylogenetic relationship between the isolates sequenced in this study and a further 23 Alternaria spp. based on available genomes. We determine which of these genomes represent MAT1-1-1 or MAT1-2-1 idiomorphs and designate host-specific pathotypes. We show for the first time that the apple pathotype is polyphyletic, present in both the A. arborescens and A. tenuissima lineages. Furthermore, we profile a wider set of 89 isolates for both mating type idiomorphs and toxin gene markers. Mating-type distribution indicated that gene flow has occurred since the formation of A. tenuissima and A. arborescens lineages. We also developed primers designed to AMT14, a gene from the apple pathotype toxin gene cluster with homologs in all tested pathotypes. These primers allow identification and differentiation of apple, pear, and strawberry pathotypes, providing new tools for pathogen diagnostics.
    • Non-destructive genome skimming for aquatic copepods

      Vakati, Vinod; Dodsworth, Steven; Neijiang Normal University; Hanyang University; University of Bedfordshire (Springer, 2020-01-21)
      Copepods are important ecologically and represent a large amount of aquatic biomass in both freshwater and marine systems. Despite this, the taxonomy of copepods and other meiofauna is not well understood, hampered by tiny sizes, cryptic taxa, intraspecific polymorphisms and total specimen destruction where DNA methods are employed. In this article we highlight these issues and propose a more up-to-date approach for dealing with them. Namely, we recommend non-destructive DNA extraction methods, coupled with high-throughput sequencing (HTS). Whilst DNA yields may be low, they should still be sufficient for HTS library preparation and DNA sequencing. At the same time morphological specimens can be preserved and the crucial link between morphology and DNA sequence is maintained. This is critical for an integrative taxonomy and a fuller understanding of biodiversity patterns as well as evolutionary processes in meiofauna.
    • The origin and diversification of the hyperdiverse flora in the Chocó biogeographic region

      Pérez-Escobar, Oscar Alejandro; Lucas, Eve; Jaramillo, Carlos; Monro, Alexandre; Morris, Sarah K.; Bogarín, Diego; Greer, Deborah; Dodsworth, Steven; Aguilar-Cano, José; Sanchez Meseguer, Andrea; et al. (Frontiers, 2019-12-06)
      Extremely high levels of plant diversity in the American tropics are derived from multiple interactions between biotic and abiotic factors. Previous studies have focused on macro-evolutionary dynamics of the Tropical Andes, Amazonia, and Brazil’s Cerrado and Atlantic forests during the last decade. Yet, other equally important Neotropical biodiversity hotspots have been severely neglected. This is particularly true for the Chocó region on the north-western coast of South and Central America. This geologically complex region is Earth’s ninth most biodiverse hotspot, hosting approximately 3% of all known plant species. Here, we test Gentry’s [1982a,b] hypothesis of a northern Andean-Central American Pleistocene origin of the Chocoan flora using phylogenetic reconstructions of representative plant lineages in the American tropics. We show that plant diversity in the Chocó is derived mostly from Andean immigrants. Contributions from more distant biogeographical areas also exist but are fewer. We also identify a strong floristic connection between the Chocó and Central America, revealed by multiple migrations into the Chocó during the last 5 Ma. The dated phylogenetic reconstructions suggest a Plio-Pleistocene onset of the extant Chocó flora. Taken together, these results support to a limited extend Gentry’s hypothesis of a Pleistocene origin and of a compound assembly of the Chocoan biodiversity hotspot. Strong Central American–Chocoan floristic affinity may be partly explained by the accretion of a land mass derived from the Caribbean plate to north-western South America. Additional densely sampled phylogenies of Chocoan lineages also well represented across the Neotropics could enlighten the role of land mass movements through time in the assembly of floras in Neotropical biodiversity hotspots.
    • Factors affecting targeted sequencing of 353 nuclear genes from herbarium specimens spanning the diversity of angiosperms

      Brewer, Grace E.; Clarkson, James J.; Maurin, Olivier; Zuntini, Alexandre R.; Barber, Vanessa; Bellot, Sidonie; Biggs, Nicola; Cowan, Robyn S.; Davies, Nina M.; Dodsworth, Steven; et al. (Frontiers, 2019-09-12)
      The world’s herbaria collectively house millions of diverse plant specimens, including endangered or extinct species and type specimens. Unlocking genetic data from the typically highly degraded DNA obtained from herbarium specimens was difficult until the arrival of high-throughput sequencing approaches, which can be applied to low quantities of severely fragmented DNA. Target enrichment involves using short molecular probes that hybridise and capture genomic regions of interest for high-throughput sequencing. In this study on herbariomics, we used this targeted sequencing approach and the Angiosperms353 universal probe set to recover up to 351 nuclear genes from 435 herbarium specimens that are up to 204 years old and span the breadth of angiosperm diversity. We show that on average 207 genes were successfully retrieved from herbarium specimens, although the mean number of genes retrieved and target enrichment efficiency is significantly higher for silica gel-dried specimens. Forty-seven target nuclear genes were recovered from a herbarium specimen of the critically endangered St Helena boxwood, Mellissia begoniifolia, collected in 1815. Herbarium specimens yield significantly less high molecular weight DNA than silica gel-dried specimens, and genomic DNA quality declines with sample age which is negatively correlated with target enrichment efficiency. Climate, taxon-specific traits, and collection strategies additionally impact target sequence recovery. We also detected taxonomic bias in targeted sequencing outcomes for the 10 most numerous angiosperm families that were investigated in depth. We recommend that 1) for species distributed in wet tropical climates, silica gel-dried specimens should be used preferentially, 2) for species distributed in seasonally dry tropical climates, herbarium and silica gel-dried specimens yield similar results, and either collection can be used, 3) taxon specific traits should be explored and established for effective optimisation of taxon-specific studies using herbarium specimens, 4) all herbarium sheets should, in future, be annotated with details of the preservation method used, 5) long-term storage of herbarium specimens should be in stable low humidity and low temperature environments, and 6) targeted sequencing with universal probes, such as Angiosperms353 should be investigated closely as a new approach for DNA barcoding that will ensure better exploitation of herbarium specimens than traditional Sanger sequencing approaches.
    • Crystal structure of zinc-α2-glycoprotein in complex with a fatty acid reveals multiple different modes of protein-lipid binding

      Lau, Andy M.; Zahid, Henna; Gor, Jayesh; Perkins, Stephen J.; Coker, Alun R.; McDermott, Lindsay C.; University College London; University of Bedfordshire (Portland Press, 2019-09-10)
      Human zinc-α2-glycoprotein (ZAG) is a 42 kDa adipokine which regulates body fat mass and is associated with cachexia and obesity. ZAG belongs to the major histocompatibility complex class I protein family and binds long chain polyunsaturated fatty acids in its groove formed from the α1 and α2 domains. To identify the molecular basis of its lipid-binding function, we determined the first crystal structure at 2.49Å resolution for fatty acid-bound ZAG, where the ligand was the fluorescent 11-(dansylamino)undecanoic acid (DAUDA). The 192 kDa crystallographic asymmetric unit contained six ZAG and eight fatty acid molecules in unique conformations. Six fatty acid molecules were localised to the ZAG grooves, where its tails were bound in two distinct conformations. The carboxylate groups of three fatty acids projected out of the groove, while the fourth was hydrogen bonded with R73 inside the groove. Other ligand-residue contacts were primarily hydrophobic. A new fatty acid site was revealed for two further DAUDA molecules at the ZAG α3 domains. Following conformational changes from unbound ZAG, the α3 domains formed tetrameric β-barrel structures lined by fatty acid molecules that doubled the binding capacity of ZAG. Analytical ultracentrifugation revealed that ZAG in solution was a monomer in the absence of DAUDA, but formed small amounts of tetramers with DAUDA. By showing that ZAG binds fatty acids in different locations, we demonstrate an augmented mechanism for fatty acid binding in ZAG that is distinct from other known fatty acid binding proteins, and may be relevant to cachexia.
    • Hyb-Seq for flowering plant systematics

      Dodsworth, Steven; Pokorny, Lisa; Johnson, Matthew G.; Kim, Jan T.; Maurin, Olivier; Wickett, Norman J.; Forest, Felix; Baker, William J.; Royal Botanic Gardens, Kew; University of Bedfordshire; et al. (Cell Press, 2019-08-30)
      High-throughput DNA sequencing (HTS) presents great opportunities for plant systematics, yet genomic complexity needs to be reduced for HTS to be effectively applied. We highlight Hyb-Seq as a promising approach, especially in light of the recent development of probes enriching 353 low-copy nuclear genes from any flowering plant taxon.
    • The climatic challenge: which plants will people use in the next century?

      Borrell, J.S.; Dodsworth, Steven; Forest, Felix; Pérez-Escobar, Oscar Alejandro; Lee, M.A.; Mattana, E.; Stevenson, P.C.; Howes, M.-J.R.; Pritchard, H.W.; Ballesteros, D.; et al. (Elsevier, 2019-08-30)
      More than 31,000 useful plant species have been documented to fulfil needs and services for humans or the animals and environment we depend on. Despite this diversity, humans currently satisfy most requirements with surprisingly few plant species; for example, just three crops – rice, wheat and maize – comprise more than 50% of plant derived calories. Here, we synthesize the projected impact of global climatic change on useful plants across the spectrum of plant domestication. We illustrate the demographic, spatial, ecophysiological, chemical, functional, evolutionary and cultural traits that are likely to characterise useful plants and their resilience in the next century. Using this framework, we consider a range of possible pathways for future human use of plants. These are centred on two trade-offs: i) diversification versus specialization in the range of species we utilize, and ii) substitutionof the species towards those better suited to future climate versus facilitating adaptation in our existing suite of dominant useful plants. In the coming century, major challenges to agriculture and biodiversity will be dominated by increased climatic variation, shifting species ranges, disruption to biotic interactions, nutrient limitation and emerging pests and pathogens. These challenges must be mitigated, whilst enhancing sustainable production to meet the needs of a growing population and a more resource intensive standard of living. With the continued erosion of biodiversity, our future ability to choose among these pathways and trade-offs is likely to be diminished.
    • Ferulic acid ameliorates pentylenetetrazol-induced seizures by reducing neuron cell death

      Zhang, Shu-Hong; Liu, Donghai; Hu, Qingyun; Zhu, Jinling; Wang, Shuqiu; Zhou, Shaobo; Jiamusi University; University of Bedfordshire (Elsevier, 2019-08-05)
      Abstract: To investigate the neuroprotective effect of ferulic acid (FA) in a pentylenetetrazol (PTZ)-induced seizures rat model, the seizures behaviour, spatial learning ability and memory capability of the rats were assessed. Both the antioxidation and anti-apoptosis pathways were also investigated. In this study, male Wistar rats were randomly divided into 3 groups (n = 12 in each group). For 28 days, the rats were administered saline alone (i.p. normal saline, NS group), PTZ (40 mg/kg, i.p., PTZ group) once daily to induce seizures, or FA (i.p. 60 mg/kg) 20 min before being given PTZ (40 mg/kg, i.p., FA + PTZ group) to assess the neuroprotective effect of FA. The seizures behaviour of the rats was analysed with the Racine scale. The spatial learning and memory capacity of the rats were assessed by the Morris water maze test. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were measured, and both in situ staining with the DNA-binding bisbenzimide Hoechst 33258 and TUNEL assays were used to assess apoptosis. Western blotting was used to further analyse the expression of Apaf-1, caspase-9, caspase-3, Bcl-2, Bid, Bax, cleaved caspase-3 and cytochrome c. The results showed that compared to the those of the PTZ group, FA pre-treatment significantly (p < 0.01) reduced the Racine scores starting at day 4, prolonged the latency of the onset of seizure at day 28, reduced the escape latency period starting at day 2, increased the frequency of crossing the platform location, increased the SOD activity, reduced the MDA content and apoptosis rate, and upregulated the Bcl-2 levels whilst downregulating the Bax, cytochrome c, Apaf-1, caspase-9, caspase-3, cleaved caspase-3 and Bid expression levels. This study demonstrated that pre-treatment with FA exerts strong neuroprotective effects by reducing seizures behaviour and by improving spatial learning ability and memory capacity. The neuroprotective effect may be a result of a reduction in neuron cell death that occurs via the antioxidative and anti-apoptotic pathways. 
    • Hedgehog signalling promotes Th2-differentiation in naive human CD4 T-cells

      Yánez, Diana C.; Lau, Ching-In; Chawda, Mira Manilal; Ross, Susan; Furmanski, Anna L.; Crompton, Tessa; University College London; University of Bedfordshire; Universidad San Francisco de Quito (Journal of Allergy and Clinical Immunology, 2019-07-24)
      Original journal article Abstract: Here we show that differentiation of human naïve CD4 T-cells to Th2 is promoted by Hedgehog signaling and attenuated by SMO-inhibition. As Hedgehog proteins are produced by epithelial tissues this finding is important to understanding atopic disease.
    • ATP-specificity of succinyl-CoA synthetase from Blastocystis hominis

      Huang, Ji; Nguyen, Vinh H.; Hamblin, Karleigh; Maytum, Robin; van der Giezen, Mark; Fraser, Marie E.; (International Union of Crystallography, 2019-07-08)
      Succinyl‐CoA synthetase (SCS) catalyzes the only step of the tricarboxylic acid cycle that leads to substrate‐level phosphorylation. Some forms of SCS are specific for ADP/ATP or for GDP/GTP, while others can bind all of these nucleotides, generally with different affinities. The theory of `gatekeeper' residues has been proposed to explain the nucleotide‐specificity. Gatekeeper residues lie outside the binding site and create specific electrostatic interactions with incoming nucleotides to determine whether the nucleotides can enter the binding site. To test this theory, the crystal structure of the nucleotide‐binding domain in complex with Mg2+‐ADP was determined, as well as the structures of four proteins with single mutations, K46βE, K114βD, V113βL and L227βF, and one with two mutations, K46βE/K114βD. The crystal structures show that the enzyme is specific for ADP/ATP because of interactions between the nucleotide and the binding site. Nucleotide‐specificity is provided by hydrogen‐bonding interactions between the adenine base and Gln20β, Gly111β and Val113β. The O atom of the side chain of Gln20β interacts with N6 of ADP, while the side‐chain N atom interacts with the carbonyl O atom of Gly111β. It is the different conformations of the backbone at Gln20β, of the side chain of Gln20β and of the linker that make the enzyme ATP‐specific. This linker connects the two subdomains of the ATP‐grasp fold and interacts differently with adenine and guanine bases. The mutant proteins have similar conformations, although the L227βF mutant shows structural changes that disrupt the binding site for the magnesium ion. Although the K46βE/K114βD double mutant of Blastocystis hominis SCS binds GTP better than ATP according to kinetic assays, only the complex with Mg2+‐ADP was obtained.
    • Effect of culture medium on morphogenic processes in vitro in Cinchona officinalis L.

      Moreno Serrano, José Antonio; Pérez Ruíz, César; Moreno Fierro, Ivonne; Moreno Fierro, Jorge (Facultad de Ciencias Agrarias. Universidad Nacional de Cuyo, 2019-06-30)
      This paper describes the effect of the various plant growth regulators of the culture medium on morphogenic processes in vitro in Cinchona officinalis L, a highly vulnerable species from southern Ecuador. To do this, different concentrations of NaOCl were used in combination with different immersion times for seed disinfection; for seed germination in vitro GA3 was added to the MS basal culture medium in different concentrations, and for morphogenic processes in vitro, different concentrations of auxins and cytokinins were combined. The decrease in the contamination rate was with high concentrations of NaOCl and an increase in the germination rate in 45 days with the addition of 1.0 mg L-1 GA3 to the culture medium the hormonal combination of 0.5 mg L-1 NAA + 2.5 mg L-1 BAP showed a high rate of shoot proliferation and with 1.0 mg L-1 NAA a high number of roots was obtained. In the callogenesis phase, the best results were obtained with 1.0 mg L-1 2,4-D + 0.5 mg L-1 BAP for callus proliferation. In vitro propagation protocols were generated in Cinchona officinalis L, for the preservation and conservation of the species.
    • Negative regulation of autophagy in activating nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasomes in the hippocampus of an epilepsy rat model

      Wu, Jia-Mei; Chen, Liqiang; Wang, Shuo; Li, Yingyu; Liu, Lei; Chen, Guang; Wang, Shu-Qiu; Zhou, Shaobo (American Scientific Publishers, 2019-06-25)
      Epilepsy, characterized by unpredictable and periodic seizures, is associated with chronic hippocampal inflammation and autophagy. Moreover, a molecular relationship between autophagy and inflammation in neurodegenerative disorders has been reported, highlighting the role of autophagy in the regulation of inflammation. To the best of our knowledge, there is no previous evidence of an association between nucleotide-binding oligomerization domain-like receptor family pyrin domaincontaining 3 (NLRP3) inflammasome and autophagy in epilepsy. Hence, we in this study aimed at investigating the possible association between NLRP3 inflammasome activation and autophagy in the development of epilepsy. A rat model of temporal lobe epilepsy was induced with lithiumpilocarpine. Five groups, i.e., control (n=20), status epilepticus (SE, n=30), SE+control (siRNA; n=15), SE+NLRP3 siRNA (n=30), and SE+wortmannin (n=30), were investigated. Real-time quantitative reverse transcription polymerase chain reaction, Western blotting, and quantum dotbased immunohistochemistry were used to detect the mRNA/protein expression levels of NLRP3, caspase-1, interleukin (IL)-1, IL-18, Beclin-1, and microtubule-associated protein light chain 3 (LC3) in the hippocampus. In addition, transmission electron microscopy was utilized to investigate autophagosome in the hippocampus of SE rats. We found that mRNA and protein expressions of NLRP3, caspase-1, IL-1, IL-18, LC3, and Beclin-1 were activated in the hippocampus. Gene silencing of NLRP3 suppressed caspase-1, IL-1, and IL-18 release and significantly ameliorated hippocampal damage. Furthermore, the LC3 and Beclin-1 expression levels decreased significantly after treatment with wortmannin. Importantly, NLRP3 inflammasome activation and IL-1/IL-18 releases were significantly enhanced after treatment with wortmannin, which implied a negative association between autophagy inhibition and NLRP3 inflammasome activation. Our study provides the first evidence that autophagy plays an important role in NLRP3 inflammasome activation in the development of epilepsy. These findings suggest that regulation of autophagy may be a promising potential strategy for treating patients with epilepsy.
    • Tandem oligomeric expression of metallothionein enhance heavy metal tolerance and bioaccumulation in Escherichia coli.

      Ma, Wenli; Li, Xuefen; Wang, Qi; Ren, Zhumei; Crabbe, M. James C.; Wang, Lan; Shanxi University; University of Oxford; University of Bedfordshire (Elsevier, 2019-06-13)
      Metallothioneins (MTs) are a family of low molecular weight, cysteine-rich, metal-binding proteins, which play important roles in metal homeostasis and heavy metal detoxification. In our previous study, a novel full length MT cDNA was successfully cloned from the freshwater crab (Sinopotamon henanense). In the present study, tandem repeats of two and three copies of the crab MT gene were integrated by overlap extension PCR (SOEPCR) and expressed in Escherichia coli. The SUMO fusion expression system was adopted to increase the stability and solubility of the recombinant MT proteins. The recombinant proteins were purified and their metal-binding abilities were further analyzed by the ultraviolet absorption spectral scan. Furthermore, the metal tolerance and bioaccumulation of E. coli cells expressing oligomeric MTs were determined. Results showed that the recombinant plasmids pET28a-SUMO-2MT and pET28a-SUMO-3MT were successfully constructed. SDS-PAGE analysis showed that the SUMO-2MT and SUMO-3MT were expressed mainly in the soluble forms. Oligomeric MTs expression significantly enhanced Cu, Cd or Zn tolerance and accumulation in E. coli in the order: SUMO-3MT˃SUMO-2MT˃SUMO-MT˃control. Cells harboring pET28a-SUMO -3MT exhibited the highest Cu, Cd or Zn bioaccumulation at 5.8-fold, 3.1-fold or 6.7-fold higher than that of the control cells. Our research could lay a foundation for large-scale preparation of MTs and provide a scientific basis for bioremediation of heavy metal pollution by oligomeric MTs.
    • Adaptive changes of glioblastoma cells following exposure to hypoxic (1% oxygen) tumour microenvironment.

      Musah-Eroje, Ahmed; Watson, Sue; University of Nottingham; University of Bedfordshire (MDPI, 2019-04-28)
      Glioblastoma multiforme is the most aggressive and malignant primary brain tumour, with a median survival rate of between 15 to 17 months. Heterogeneous regions occur in glioblastoma as a result of oxygen gradients which ranges from 0.1% to 10% in vivo. Emerging evidence suggests that tumour hypoxia leads to increased aggressiveness and chemo/radio resistance. Yet, few in vitro studies have been performed in hypoxia. Using three glioblastoma cell-lines (U87, U251, and SNB19), the adaptation of glioblastoma cells in a 1% (hypoxia) and 20% (normoxia) oxygen microenvironment on proliferation, metabolism, migration, neurosphere formation, CD133 and VEGF expression was investigated. Compared to cells maintained in normoxia (20% oxygen), glioblastoma cells adapted to 1% oxygen tension by reducing proliferation and enhancing metabolism. Both migratory tendency and neurosphere formation ability were greatly limited. In addition, hypoxic-mediated gene upregulation (CD133 and VEGF) was reversed when cells were removed from the hypoxic environment. Collectively, our results reveal that hypoxia plays a pivotal role in changing the behaviour of glioblastoma cells. We have also shown that genetic modulation can be reversed, supporting the concept of reversibility. Thus, understanding the degree of oxygen gradient in glioblastoma will be crucial in personalising treatment for glioblastoma patients.