Biology subjects

Anderson, B.

Publications and source records attributed to Anderson, B..

26 records · Page 2Linked to original sources

bioRxiv2020

Heterologous expression of cryptomaldamide in a cyanobacterial host

Filamentous marine cyanobacteria make a variety of bioactive molecules that are produced by polyketide synthases, non-ribosomal peptide synthetases, and hybrid pathways that are encoded by large biosynthetic gene clusters. These cyanobacterial natural products represent potential drugs leads; however, thorough pharmacological investigations have been impeded by the limited quantity of compound that is typically available from the native organisms. Additionally, investigations of the biosynthetic gene clusters and enzymatic pathways have been difficult due to the inability to conduct genetic manipulations in the native producers. Here we report a set of genetic tools for the heterologous expression of biosynthetic gene clusters in the cyanobacteria Synechococcus elongatus PCC 7942 and Anabaena (Nostoc) PCC 7120. To facilitate the transfer of gene clusters in both strains, we engineered a strain of Anabaena that contains S. elongatus homologous sequences for chromosomal recombination at a neutral site and devised a CRISPR-based strategy to efficiently obtain segregated double recombinant clones of Anabaena. These genetic tools were used to express the large 28.7 kb cryptomaldamide biosynthetic gene cluster from the marine cyanobacterium Moorena (Moorea) producens JHB in both model strains. S. elongatus did not produce cryptomaldamide, however high-titer production of cryptomaldamide was obtained in Anabaena. The methods developed in this study will facilitate the heterologous expression of biosynthetic gene clusters isolated from marine cyanobacteria and complex metagenomic samples. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/267179v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@660caforg.highwire.dtl.DTLVardef@1cab871org.highwire.dtl.DTLVardef@130de4org.highwire.dtl.DTLVardef@f50c64_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2020

Algorithmic Learning for Auto-deconvolution of GC-MS Data to Enable Molecular Networking within GNPS.

Gas chromatography-mass spectrometry (GC-MS) represents an analytical technique with significant practical societal impact. Spectral deconvolution is an essential step for interpreting GC-MS data. No public GC-MS repositories that also enable repository-scale analysis exist, in part because deconvolution requires significant user input. We therefore engineered a scalable machine learning workflow for the Global Natural Product Social Molecular Networking (GNPS) analysis platform to enable the mass spectrometry community to store, process, share, annotate, compare, and perform molecular networking of GC-MS data. The workflow performs auto-deconvolution of compound fragmentation patterns via unsupervised non-negative matrix factorization, using a Fast Fourier Transform-based strategy to overcome scalability limitations. We introduce a "balance score" that quantifies the reproducibility of fragmentation patterns across all samples. We demonstrate the utility of the platform with breathomics analysis applied to the early detection of oesophago-gastric cancer, and by creating the first molecular spatial map of the human volatilome.

bioinformatics↗

bioRxiv2019

GHSR-1a is not Required for Ghrelin's Anti-inflammatory and Fat-sparing Effects in Cancer Cachexia

Adipose tissue (AT) atrophy is a hallmark of cancer cachexia contributing to increased morbidity/mortality. Ghrelin has been proposed as a treatment for cancer cachexia partly by preventing AT atrophy. However, the mechanisms mediating ghrelins effects are incompletely understood, including the extent to which its only known receptor, GHSR-1a, is required for these effects. This study characterizes the pathways involved in AT atrophy in the Lewis Lung Carcinoma (LLC)-induced cachexia model and those mediating the effects of ghrelin in Ghsr+/+ and Ghsr-/- mice. We show that LLC causes AT atrophy by inducing anorexia, and increasing AT inflammation, thermogenesis and energy expenditure. These changes were greater in Ghsr-/-. Ghrelin administration prevented LLC-induced anorexia only in Ghsr+/+, but prevented WAT inflammation and atrophy in both genotypes, although its effects were greater in Ghsr+/+. LLC-induced increases in BAT inflammation, WAT and BAT thermogenesis, and energy expenditure were not affected by ghrelin. In conclusion, ghrelin ameliorates WAT inflammation, fat atrophy and anorexia in LLC-induced cachexia. GHSR-1a is required for ghrelins orexigenic effect but not for its anti-inflammatory or fat-sparing effects.

cancer biology↗

bioRxiv2019

Cerebellar lesions disrupt spatial and temporal visual attention.

The current study represents the first comprehensive examination of spatial, temporal and sustained attention following cerebellar damage. Results indicated that, compared to controls, cerebellar damage resulted in a larger cueing effect at the longest SOA - possibly reflecting a slowed the onset of inhibition of return (IOR) during a reflexive covert attention task, and reduced the ability to detect successive targets during an attentional blink task. However, there was little evidence to support the notion that cerebellar damage disrupted voluntary covert attention or the sustained attention to response task (SART). Lesion overlay data and supplementary voxel-based lesion symptom mapping (VLSM) analyses indicated that impaired performance on the reflexive covert attention and attentional blink tasks were related to damage to Crus II of the left posterior cerebellum. In addition, subsequent analyses indicated our results are not due to either general motor impairments or to damage to the deep cerebellar nuclei. Collectively these data demonstrate, for the first time, that the same cerebellar regions may be involved in both spatial and temporal visual attention.

neuroscience↗

bioRxiv2019

Cross-compatibility of five highbush blueberry varieties and ideal crossing combinations

Blueberry plants require large quantities of pollen deposited on stigmas to produce commercial-quality fruit. Like many agricultural crops, the interaction between pollen-source variety and pollen-recipient variety can be a major determinant of fruit quality in blueberries. However, little information exists to guide growers in optimising fruit set and quality. Using five commonly grown blueberry varieties, I determined whether crossing between varieties (inter-varietal) increased fruit mass and decreased developmental time relative to crossing within a variety (intra-varietal), and if so, what the best crossing combinations are. While intra-varietal pollination often produced fruit, for certain varieties the fruit set and fruit mass were highly reduced compared to inter-varietal pollination. Furthermore, intra-varietal pollination resulted in longer fruit developmental time in comparison to pollination between varieties. For the same pollen-recipient variety, inter-varietal crosses typically outperformed intra-varietal crosses in fruit mass and developmental time; however, the extent to which inter-varietal crosses outperformed intra-varietal crosses differed between pollen-donor varieties. This result suggests that combinations of varieties are not trivial as some inter-varietal combinations may outperform others. Furthermore, some varieties appear to be more susceptible to the negative effects of intra-varietal crosses than others and that less susceptible varieties may be better suited to conditions where pollinator movement is poor. While our study can guide growers in determining optimal co-planting schemes for the varieties tested, for example in South Africa where these varieties are frequently grown. It also serves as a blueprint for similar compatibility studies that can easily be performed prior to planting to determine the best inter-varietal combinations.

plant biology↗

bioRxiv2019

Honey bees, Apis mellifera, are important pollinators of the highbush blueberry variety Ventura despite the inability to sonicate

Animal-mediated pollination is an essential ecosystem service which over a third of the worlds agricultural crops depend on. Blueberry fruit production is highly dependent on pollinators and in their native range they are pollinated mostly by bumble bees (Bombus spp.). Demand for blueberries has increased in recent years due to their perceived health benefits. Consequently, blueberry cultivation has expanded well beyond their native range, including several regions where bumble bees are not present. In many areas, honey bees may be the only commercially available pollinators of blueberries because many countries ban the importation of bumble bees. This study aimed to determine the benefits of honey bee pollination on blueberry fruit quality and quantity for the variety Ventura by comparing yields of honey-bee-pollinated flowers to flowers where pollinators had been excluded. Honey bees significantly increased berry mass and diameter. Our results suggest that the presence of honey bee pollinators potentially increases revenue by approximately $864 501/ha in areas without bumble bees. We conclude that Ventura is reliably pollinated by honey bees, and that honey bee pollination may be a useful substitute for bumble bees in areas where bumble bees are absent. We also determined the extent to which blueberry yields could still be improved by comparing fruit quality and quantity under honey bee pollination to fruit quality and quantity achieved through ideal hand pollination. We found that blueberry yields may be still be significantly increased relative to ideal hand pollination and we discuss potential ways to improve the efficiency of honeybee pollination in the future. Additional research is required to study how beneficial honey bees are to fruit yield on varieties as the benefits of honey bees are likely to vary across different varieties.

plant biology↗

bioRxiv2019

A rabbit monoclonal antibody against the antiviral and cancer genomic DNA mutating enzyme APOBEC3B

The DNA cytosine deaminase APOBEC3B (A3B) is normally an antiviral factor in the innate immune response. However, A3B has been implicated in cancer mutagenesis, particularly in solid tumors of the bladder, breast, cervix, head/neck, and lung. Here, we report data on the generation and characterization of a rabbit monoclonal antibody (mAb) for human A3B through a series of immunoblot, immunofluorescence microscopy, and immunohistochemistry experiments. Positive results indicate that one mAb, 5210-87-13, will be useful for fundamental research in virology and cancer biology and that immunohistochemical quantification of A3B enzyme levels may constitute a clinical biomarker for tumor evolvability and differential treatment.

cancer biology↗

bioRxiv2018

A novel pollen-tracking method: using quantum dots as pollen labels

To understand the evolution of flowers and mating systems in animal-pollinated plants, we have to directly address the function for which flowers evolved--the movement of pollen from anthers to stigmas. However, despite a long history of making significant advances in our understanding natural selection and evolution, the field of pollination biology has largely studied pollen movement indirectly (e.g., pollen analogues or paternity assignment to seeds) due to a lack of suitable pollen tracking methods. Here, we develop and test a novel pollen-tracking technique using quantum dots as pollen-grain labels. Quantum dots are semiconductor nanocrystals so small in size that they behave like artificial atoms. When exposed to UV light, they emit extremely bright light in a range of different colours. Their photostability, broad excitation range, and customisable binding-li-gands make quantum dots ideal bio-labels. We tested the suitability of CuInSexS2-x/ZnS (core/shell) quantum dots with oleic acid (zinc-oleate complex) ligands as pollen-grain labels. We found that quantum dots attach to pollen grains of four different species even after agitation in a polar solvent, suggesting that the oleic acid ligands on quantum dots bind to pollenkitt surrounding pollen grains. We also showed that most pollen grains within anthers of the same four species are labelled with quantum dots after applying sufficient quantum-dot solution to anthers. To test whether quantum-dot pollen-labels influenced pollen transport, we conducted pollen transfer trials on Sparaxis villosa (Iridaceae) using captively reared honeybees. We found no difference in pollen transport between labelled and unlabelled pollen grains. Our experiments therefore demonstrate the potential for quantum dots to be used as easily applied pollen labels, which allow subsequent tracking of the fates of pollen grains in the field. The ability to track pollen grain movement in situ, may finally allow us to address an historically neglected aspect of plant reproductive ecology and evolution.

evolutionary biology↗