Recent Submissions

  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • The interaction of Wnt-11 and signalling cascades in prostate cancer

    Koushyar, Sarah; Grant, Guy H.; Uysal-Onganer, Pinar (Springer Netherlands, 2016-08-11)
    Prostate cancer (PCa) is the second most common cancer among the male population. Conventional therapies target androgen signalling, which drives tumour growth; however, they provide limited survival benefits for patients. It is essential, therefore, to develop a more specific biomarker than the current gold standard, PSA testing. The Wnt signalling pathway induces expression of target genes through cell surface receptors. A non-canonical member of this family, Wnt-11, is evolutionarily highly conserved and is normally expressed by various cells in the developing embryo, as well as in the heart, liver and skeletal muscle of adult humans. We comprehensively review several cell signalling pathways to explain how they interact with Wnt-11, demonstrating its use as a potential biomarker for PCa. Several studies have shown that the expression of Wnt-11 is associated with gastric, renal and colorectal adenocarcinomas and PCa. Moreover, Wnt-11 affects extracellular matrix composition and cytoskeletal rearrangement, and it is required for proliferation and/or survival during cell differentiation. It was found that PCa cell lines express high levels of Wnt-11, which allows differentiation of the epithelial prostate tumour cells to neuron-like (NE) cells. The NE cells produce additional factors that can cause regression after treatment. Accumulating evidence shows that Wnt-11 could be a potential biomarker in diagnosing PCa. Many studies have shown both non-canonical and canonical Wnts interact with several signalling cascades such as PKC, JNK, NF-κB, Rho, PKA and PI3K. In particular, evidence demonstrates Wnt-11 is involved in the progression of PCa, thus it could have the potential to become both a specific disease marker and an important therapeutic target.
  • 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.
  • Downregulation of hsa_circ_0000285 serves as a prognostic biomarker for bladder cancer and is involved in cisplatin resistance

    Wang, S.; Chi, B.; Zhao, D.; Liu, L.; Yin, X.; Wang, F.; Bi, S.; Gui, S.; Zhou, Shaobo; Qin, W.; et al. (AEPress, 2019-03-19)
    Bladder cancer remains a very challenging disease to treat with the high rates of recurrence and progression associated with current therapies. Although the association between bladder cancer pathology and circRNAs remains undetermined, circRNAs signatures may be useful as prognostic and predictive factors and clinical tools for assessing disease state, treatment response and outcome. This study investigates if these circRNAs can be used as biomarkers for bladder cancer diagnosis and predicting treatment response. Herein, qPCR measured the expression of hsa_circRNA_100783, hsa_circ_0000285 and hsa_circRNA_100782 in bladder cancer tissues. It was established that sa_circ_0000285, but not hsa_circRNA_100782 and hsa_circRNA_10078, are significantly reduced in bladder cancer tissues and serum compared to adjacent tissues and healthy controls. Moreover, hsa_circ_0000285 expression was lower in cisplatin-resistant bladder cancer patients than in those who were cisplatin-sensitive. Here, hsa_circ_0000285 was associated with tumor size (p<0.001), differentiation (p<0.001), lymph node metastasis (p=0.038), distant metastasis (p=0.004) and TNM stage (p=0.013). Further analysis showed that hsa_circ_0000285 would be an independent prognostic factor for bladder cancer patient outcome. In conclusion, our study indicates hsa_circ_0000285 may be a novel biomarker for bladder cancer because of its involvement in bladder cancer chemo-sensitivity.
  • 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.
  • WWOX sensitises ovarian cancer cells to paclitaxel via modulation of the ER stress response

    Janczar, Szymon; Nautiyal, Jaya; Xiao, Yi; Curry, Edward; Sun, Mingjun; Zanini, Elisa; Paige, Adam J.W.; Gabra, Hani; Imperial College London; Medical University of Lodz; et al. (Springer Nature, 2017-07-27)
    There are clear gaps in our understanding of genes and pathways through which cancer cells facilitate survival strategies as they become chemoresistant. Paclitaxel is used in the treatment of many cancers, but development of drug resistance is common. Along with being an antimitotic agent paclitaxel also activates endoplasmic reticulum (ER) stress. Here, we examine the role of WWOX (WW domain containing oxidoreductase), a gene frequently lost in several cancers, in mediating paclitaxel response. We examine the ER stress-mediated apoptotic response to paclitaxel in WWOX-transfected epithelial ovarian cancer (EOC) cells and following siRNA knockdown of WWOX. We show that WWOX-induced apoptosis following exposure of EOC cells to paclitaxel is related to ER stress and independent of the antimitotic action of taxanes. The apoptotic response to ER stress induced by WWOX re-expression could be reversed by WWOX siRNA in EOC cells. We report that paclitaxel treatment activates both the IRE-1 and PERK kinases and that the increase in paclitaxel-mediated cell death through WWOX is dependent on active ER stress pathway. Log-rank analysis of overall survival (OS) and progression-free survival (PFS) in two prominent EOC microarray data sets (Tothill and The Cancer Genome Atlas), encompassing ~800 patients in total, confirmed clinical relevance to our findings. High WWOX mRNA expression predicted longer OS and PFS in patients treated with paclitaxel, but not in patients who were treated with only cisplatin. The association of WWOX and survival was dependent on the expression level of glucose-related protein 78 (GRP78), a key ER stress marker in paclitaxel-treated patients. We conclude that WWOX sensitises EOC to paclitaxel via ER stress-induced apoptosis, and predicts clinical outcome in patients. Thus, ER stress response mechanisms could be targeted to overcome chemoresistance in cancer.
  • A novel 3D in vitro model of glioblastoma reveals resistance to temozolomide which was potentiated by hypoxia

    Musah-Eroje, Ahmed; Watson, Sue; University of Nottingham; University of Bedfordshire (Springer, 2019-01-29)
    Glioblastoma (GBM) is the most common invasive malignant brain tumour in adults. It is traditionally investigated in vitro by culturing cells as a monolayer (2D culture) or as neurospheres (clusters enriched in cancer stem cells) but neither system accurately reflects the complexity of the three-dimensional (3D) chemoresistant microenvironment of GBM. Using three GBM cell-lines (U87, U251, and SNB19), the effect of culturing cells in a Cultrex-based basement membrane extract (BME) [3D Tumour Growth Assay (TGA)] on morphology, gene expression, metabolism, and temozolomide chemoresistance was investigated. Cells were easily harvested from the 3D model and cultured as a monolayer (2D) and neurospheres. Indeed, the SNB19 cells formed neurospheres only after they were first cultured in the 3D model. The expression of CD133 and OCT4 was upregulated in the neurosphere and 3D assays respectively. Compared with cells cultured in the 2D model, cells were more resistant to temozolomide in the 3D model and this resistance was potentiated by hypoxia. Taken together, these results suggest that micro-environmental factors influence GBM sensitivity to temozolomide. Knowledge of the mechanisms involved in temozolomide resistance in this 3D model might lead to the identification of new strategies that enable the more effective use of the current standard of care agents. PURPOSE MATERIALS AND METHODS RESULTS CONCLUSION
  • 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.
  • 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.
  • 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.
  • A novel human neuronal cell model to study iron accumulation in Parkinson’s disease

    Mehta, Kosha; Ahmed, Bushra Y.; Farnaud, Sébastien; University of Bedfordshire (OMICS International, 2019-02-11)
    Objectives: With an estimated seven to ten million sufferers worldwide, Parkinson’s disease (PD) is the second most common age-related neurodegenerative disorder. Progress in elucidating its causes has been slow, partly due to the lack of human-relevant models. Similarly, while the contribution of iron is increasingly advocated, identifying its role in disease progression remains challenging mainly due to the lack of valid model. In this study, we created Parkinson-like conditions in a human neuron model and conducted preliminary studies on iron-related parameters to assess whether these cells replicated iron accumulation observed in Parkinsonism. Methods: ReNcell VM (human neural progenitor) were differentiated into dopaminergic neurons (dDCNs) and treated with neurotoxin 6-hydroxy dopamine (100 μM) to mimic Parkinsonism. Total intracellular, mitochondrial and cytoplasmic iron was measured by ferrozine assay. Expression of iron-related genes TFRC, SLC40A1, HAMP and SLC25A37 were assessed through real-time PCR. Results: Data showed that the treated dDCNs accumulated iron over time and exceeded levels measured in untreated dDCNs by 2.5-fold at 48 h (p<0.02). Following the treatment, the treated cells showed lower expression of TFRC (p<0.05), but substantially higher mRNA expressions of SLC40A1 (9-fold; p<0.02) and HAMP (5.7-fold; p<0.05), along with higher intracellular iron (p<0.05). Higher iron accumulation in the mitochondria than cytosol (p<0.05), was also observed with increased expression of the mitochondrial iron-importer SLC25A37 (p=0.08). Conclusion: Our Parkinsonian model demonstrates iron accumulation and elevated HAMP expression as previously described in PD phenotype. The observed mitochondrial iron shuttling, which is proposed to be one of the primary contributors of oxidative stress in PD, calls for further investigation. The differences observed in distribution of iron in our human model and with the expression of major iron-related proteins, indicate that our model reproduces the disease state successfully, and suggests that further study could help in advancing our understanding of PD.
  • Arsenite oxidase also functions as an antimonite oxidase

    Wang, Qian; Warelow, Thomas P.; Kang, Yoon-Suk; Romano, Christine; Osborne, Thomas H.; Lehr, Corinne R.; Bothner, Brian; McDermott, Timothy R.; Santini, Joanne M.; Wang, Gejiao; et al. (American Society for Microbiology, 2014-12-29)
    Arsenic and antimony are toxic metalloids and are considered priority environmental pollutants by the U.S. Environmental Protection Agency. Significant advances have been made in understanding microbe-arsenic interactions and how they influence arsenic redox speciation in the environment. However, even the most basic features of how and why a microorganism detects and reacts to antimony remain poorly understood. Previous work with Agrobacterium tumefaciens strain 5A concluded that oxidation of antimonite [Sb(III)] and arsenite [As(III)] required different biochemical pathways. Here, we show with in vivo experiments that a mutation in aioA [encoding the large subunit of As(III) oxidase] reduces the ability to oxidize Sb(III) by approximately one-third relative to the ability of the wild type. Further, in vitro studies with the purified As(III) oxidase from Rhizobium sp. strain NT-26 (AioA shares 94% amino acid sequence identity with AioA of A. tumefaciens) provide direct evidence of Sb(III) oxidation but also show a significantly decreased Vmax compared to that of As(III) oxidation. The aioBA genes encoding As(III) oxidase are induced by As(III) but not by Sb(III), whereas arsR gene expression is induced by both As(III) and Sb(III), suggesting that detection and transcriptional responses for As(III) and Sb(III) differ. While Sb(III) and As(III) are similar with respect to cellular extrusion (ArsB or Acr3) and interaction with ArsR, they differ in the regulatory mechanisms that control the expression of genes encoding the different Ars or Aio activities. In summary, this study documents an enzymatic basis for microbial Sb(III) oxidation, although additional Sb(III) oxidation activity also is apparent in this bacterium.

View more