Abbkine Scientific

2017年6月30日星期五

Selective depletion of uropathogenic E. coli from the gut by a FimH antagonist

Topics overview: Targeting FimH with M4284 can reduce intestinal colonization of genetically diverse UPEC isolates; Insights into the generalizable, underlying features of epitope-specific repertoires and adaptive immune recognition; The function of H3K9me2 and H3K9me3; The association of Parkinson’s disease with alleles of the major histocompatibility complex; Analytical tools to identify which host species are likely to harbour the next human virus.

1. Selective depletion of uropathogenic E. coli from the gut by a FimH antagonist.

Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) affect 150 million people annually. Despite effective antibiotic therapy, 30–50% of patients experience recurrent UTIs. In addition, the growing prevalence of UPEC that are resistant to last-line antibiotic treatments, and more recently to carbapenems and colistin, make UTI a prime example of the antibiotic-resistance crisis and emphasize the need for new approaches to treat and prevent bacterial infections. UPEC strains establish reservoirs in the gut from which they are shed in the faeces, and can colonize the periurethral area or vagina and subsequently ascend through the urethra to the urinary tract, where they cause UTIs. UPEC isolates encode up to 16 distinct chaperone-usher pathway pili, and each pilus type may enable colonization of a habitat in the host or environment. For example, the type 1 pilus adhesin FimH binds mannose on the bladder surface, and mediates colonization of the bladder. However, little is known about the mechanisms underlying UPEC persistence in the gut. Here, using a mouse model, Caitlin N. Spaulding at Washington University in Missouri, USA and his colleagues show that F17-like and type 1 pili promote intestinal colonization and show distinct binding to epithelial cells distributed along colonic crypts. Phylogenomic and structural analyses reveal that F17-like pili are closely related to pilus types carried by intestinal pathogens, but are restricted to extra-intestinal pathogenic E. coli. Moreover, they show that targeting FimH with M4284, a high-affinity inhibitory mannoside, reduces intestinal colonization of genetically diverse UPEC isolates, while simultaneously treating UTI, without notably disrupting the structural configuration of the gut microbiota. By selectively depleting intestinal UPEC reservoirs, mannosides could markedly reduce the rate of UTIs and recurrent UTIs.

2. Quantifiable predictive features define epitope-specific T cell receptor repertoires.

T cells are defined by a heterodimeric surface receptor, the T cell receptor (TCR), that mediates recognition of pathogen-associated epitopes through interactions with peptide and major histocompatibility complexes (pMHCs). TCRs are generated by genomic rearrangement of the germline TCR locus, a process termed V(D)J recombination, that has the potential to generate marked diversity of TCRs (estimated to range from 10¹⁵to as high as 10⁶¹ possible receptors). Despite this potential diversity, TCRs from T cells that recognize the same pMHC epitope often share conserved sequence features, suggesting that it may be possible to predictively model epitope specificity. Here Pradyot Dash at St Jude Children’s Research Hospital in Tennessee, USA and his colleagues report the in-depth characterization of ten epitope-specific TCR repertoires of CD8⁺ T cells from mice and humans, representing over 4,600 in-frame single-cell-derived TCRαβ sequence pairs from 110 subjects. They developed analytical tools to characterize these epitope-specific repertoires: a distance measure on the space of TCRs that permits clustering and visualization, a robust repertoire diversity metric that accommodates the low number of paired public receptors observed when compared to single-chain analyses, and a distance-based classifier that can assign previously unobserved TCRs to characterized repertoires with robust sensitivity and specificity. Their analyses demonstrate that each epitope-specific repertoire contains a clustered group of receptors that share core sequence similarities, together with a dispersed set of diverse ‘outlier’ sequences. By identifying shared motifs in core sequences, they were able to highlight key conserved residues driving essential elements of TCR recognition. These analyses provide insights into the generalizable, underlying features of epitope-specific repertoires and adaptive immune recognition.

3. Unique roles for histone H3K9me states in RNAi and heritable silencing of transcription.

Heterochromatic DNA domains play important roles in regulation of gene expression and maintenance of genome stability by silencing repetitive DNA elements and transposons. From fission yeast to mammals, heterochromatin assembly at DNA repeats involves the activity of small noncoding RNAs (sRNAs) associated with the RNA interference (RNAi) pathway. Typically, sRNAs, originating from long noncoding RNAs, guide Argonaute-containing effector complexes to complementary nascent RNAs to initiate histone H3 lysine 9 di- and tri-methylation (H3K9me2 and H3K9me3, respectively) and heterochromatin formation. H3K9me is in turn required for recruitment of RNAi to chromatin to promote sRNA amplification. Yet, how heterochromatin formation, which silences transcription, can proceed by a co-transcriptional mechanism that also promotes sRNA generation remains paradoxical. Here, using Clr4, the fission yeast S. pombe homolog of mammalian SUV39H H3K9 methyltransferases, Gloria Jih at Harvard Medical School in Massachusetts, USA and her colleagues designed active site mutations that block H3K9me3, but allow H3K9me2 catalysis. They show that H3K9me2 defines a functionally distinct heterochromatin state that is sufficient for RNAi-dependent co-transcriptional gene silencing (CTGS) at pericentromeric DNA repeats. Unlike H3K9me3 domains, which are transcriptionally silent, H3K9me2 domains are transcriptionally active, contain modifications associated with euchromatic transcription, and couple RNAi-mediated transcript degradation to the establishment of H3K9me domains. The two H3K9me states recruit reader proteins with different efficiencies, explaining their different downstream silencing functions. Furthermore, transition from H3K9me2 to H3K9me3 is required for RNAi-independent epigenetic inheritance of H3K9me domains. Their findings demonstrate that H3K9me2 and H3K9me3 define functionally distinct chromatin states and uncover a mechanism for formation of transcriptionally permissive heterochromatin that is compatible with its broadly conserved role in sRNA-mediated genome defense.

4. T cells from patients with Parkinson’s disease recognize α-synuclein peptides.

Genetic studies have shown the association of Parkinson’s disease with alleles of the major histocompatibility complex. Here David Sulzer at Columbia University in New York, USA and his colleagues show that a defined set of peptides that are derived from α-synuclein, a protein aggregated in Parkinson’s disease, act as antigenic epitopes displayed by these alleles and drive helper and cytotoxic T cell responses in patients with Parkinson’s disease. These responses may explain the association of Parkinson’s disease with specific major histocompatibility complex alleles.

5. Host and viral traits predict zoonotic spillover from mammals.

The majority of human emerging infectious diseases are zoonotic, with viruses that originate in wild mammals of particular concern (for example, HIV, Ebola and SARS). Understanding patterns of viral diversity in wildlife and determinants of successful cross-species transmission, or spillover, are therefore key goals for pandemic surveillance programs. However, few analytical tools exist to identify which host species are likely to harbour the next human virus, or which viruses can cross species boundaries. Here Kevin J. Olival at EcoHealth Alliance in New York, USA and his colleagues conduct a comprehensive analysis of mammalian host–virus relationships and show that both the total number of viruses that infect a given species and the proportion likely to be zoonotic are predictable. After controlling for research effort, the proportion of zoonotic viruses per species is predicted by phylogenetic relatedness to humans, host taxonomy and human population within a species range—which may reflect human–wildlife contact. They demonstrate that bats harbour a significantly higher proportion of zoonotic viruses than all other mammalian orders. They also identify the taxa and geographic regions with the largest estimated number of ‘missing viruses’ and ‘missing zoonoses’ and therefore of highest value for future surveillance. They then show that phylogenetic host breadth and other viral traits are significant predictors of zoonotic potential, providing a novel framework to assess if a newly discovered mammalian virus could infect people.

2017年6月29日星期四

Anti-COX IV Mouse Monoclonal Antibody (14Y2) joins the Abbkine Scientific family

Wuhan, China. 430074, 29^th June 2017. Abbkine Scientific Co. Ltd has announced the release of its new Anti-COX IV Mouse Monoclonal Antibody (14Y2). COX IV, also called Cytochrome c Oxidase or Complex IV (EC 1.9.3.1), which is a large trans-membrane protein complex found in bacteria and the mitochondrion. It is located in the mitochondrial (or bacterial) membrane and is the last enzyme in the respiratory electron transport chain.

Otherwise known as the Cytochrome c oxidase polypeptide IV antibody, the COX IV antibody has a human, mouse and rat reactivity with a recombinant protein immunogen. The product is available in a liquid solution and affinity-purified from mouse ascites by affinity-chromatography using specific immunogen.

The monoclonal antibody is hosted in the mouse, with Mouse IgG1 Isotype. The uniqueness of the antibody stems from its flexibility and durability, as it can be stored for about twelve months from the date of shipment. While it is advised that investigators determine the optimal working dilutions experimentally, the suggested starting dilutions are WB 1:1000-3000, reiterating its flexibility.

COX IV antibody is usually as a Mitochondrial Loading Control.

About Abbkine Scientific

Abbkine Scientific Company Limited is a life science research company headquartered in California. Founded in 2012, the establishment has been able to spread its tentacles across the globe with increasing presence and acceptance from Asia Pacific thanks to its continuous efforts to make the world a better place.

Abbkine combines cutting edge technology with manufacturing engineering and cost advantage to provide innovative, high-quality assay kits and other research and scientific products enhance life science fundamental research and drug discovery amongst others.

2017年6月28日星期三

PDGFRα Mouse Monoclonal Antibody (7A3) Review

PDGFRα, platelet-derived growth factor receptor alpha, also termed PDGFRA, encodes a cell surface tyrosine kinase receptor for members of the platelet-derived growth factor family. This receptor binds to certain isoforms of platelet-derived growth factors (PDGFs) and thereby becomes active in stimulating cell signaling pathways that elicit responses such as cellular growth and differentiation. The receptor is critical for the development of certain tissues and organs during embryogenesis and for the maintenance of these tissues and organs, particularly hematologic tissues, throughout life. Mutations in PDGFRA have been associated with idiopathic hypereosinophilic syndrome, somatic and familial gastrointestinal stromal tumors, and a variety of other cancers.

Abbkine PDGFRα Mouse Monoclonal Antibody (7A3) takes synthetic peptide of PDGFRα at AA range of 1010-1090 as immunogen. The antibody was affinity-purified from mouse ascites by affinity-chromatography. The antibody could be used to detect endogenous levels of PDGFRA in the samples of human, rat and mouse. It has been validated in IF and IHC-p experiments. Suggested starting dilutions are: IHC-p: 1:100-200, and the researchers should explore optimal concentrations for your own tests.

Our lab bought this antibody one week ago. I stained mouse brain sections at a dilution 1:200 and there are strong signals in corpus callosum. In one word, this antibody is an excellent antibody. Also, my other colleague conducted the immunohistochemical analysis of rat spleen tissue. PDGFRα Mouse Monoclonal Antibody (7A3) was diluted at 1:200. It works well for IHC staining.

2017年6月26日星期一

ABCB5 Monoclonal Antibody Review

ATP-binding cassette sub-family B member 5 also known as P-glycoprotein ABCB5 is a plasma membrane-spanning protein that in humans is encoded by the ABCB5 gene. ABCB5 is an ABC transporter and P-glycoprotein family member principally expressed in physiological skin and human malignant melanoma. ABCB5 has been suggested to regulate skin progenitor cell fusion and mediate chemotherapeutic drug resistance in stem-like tumor cell subpopulations in human malignant melanoma. It is commonly over-expressed on circulating melanoma tumour cells.

Abbkine ABCB5 Monoclonal Antibody was affinity-purified from mouse ascites by affinity-chromatography using specific immunogen. The antibody was validated for WB, IF, IHC-p and tested to react with Human. Abbkine suggested the starting dilutions are as follows: WB: 1:2000, IF: 1:200, IHC-p: 1:200. Optimal working dilutions should be determined by users.

After several times failure of using other brands of ABCB5 Antibody, I found Abbkine through internet. What I have to say: the antibody is amazing. It saves my experiment and my time. I applied the antibody in WB, IF, IHC. All the results are in line with my expectations. Compared with other brands, the price of this antibody is even lower. There is no doubt that I’ll purchase products from Abbkine again.

2017年6月25日星期日

Abbkine Scientific launches the PurKine™ Protein L Resin

The PurKine™ Protein L Resin is the latest addition to the resin family from the stables of scientific research giant, Abbkine Scientific Company Limited. The company recently announced the official launch of the product designed to purify monoclonal antibodies from culture supernatant or ascites known to have the kappa light chain in gravity column procedures.

Otherwise known as Protein L Resin, the product has been largely described as being perfect for affinity purification of mammalian IgG containing particular kappa light chains from ascites fluid, serum, cell culture supernatant and a host of other antibody samples.

The Antibody Purification Protein L is designed to minimize nonspecific binding proteins, thanks to the proprietary modification method employed in its production. Protein L Agarose is also known to be very useful in purifying VLk-containing monoclonal antibodies from culture supernatant, as it does not bind bovine immunoglobulin present in the media serum supplement.

Available in a liquid solution, the Protein L resin consists of 90μm beads of cross-linked 4% agarose, to which Recombinant protein L has been coupled. The cost-effectiveness of the product has been validated after test results show no decrease in performance after at least five repeated uses.

The product is available in multiple formats including bulk resin, spin columns and complete kits, allowing for flexibility on the part of the users.

About Abbkine Scientific Co. Ltd

Abbkine Scientific Co. Ltd is headquartered in California. The life science research company was founded in 2012 and has subsequently reached the rest of the world, with a wide range of high quality science products and services.

Abbkine Scientific combines cutting edge technology with manufacturing engineering and cost advantage, providing high-quality and innovative assay kits and other research and scientific products designed to enhance life science fundamental research and drug discovery amongst others.

2017年6月23日星期五

Engineered bacteria can function in the mammalian gut long-term as live diagnostics of inflammation

Topics overview: What’s Metafluidics; How to solve the Cpf1 function limitation in BV3L6 and Lachnospiraceae bacterium ND2006; The breakthrough of single-cell genome sequencing to large cell populations; Bacteria can be engineered to function as diagnostics or therapeutics in the mammalian gut; TACCA was applied to produce a high-quality (N50 of 9.76 Mb) de novo chromosome assembly of the wheat line CH Campala Lr22a in only 4 months.

1. Open-source, community-driven microfluidics with Metafluidics.

Microfluidic devices have the potential to automate and miniaturize biological experiments, but open-source sharing of device designs has lagged behind sharing of other resources such as software. Synthetic biologists have used microfluidics for DNA assembly, cell-free expression, and cell culture, but a combination of expense, device complexity, and reliance on custom set-ups hampers their widespread adoption. David S Kong at Massachusetts Institute of Technology Lincoln Laboratory in Massachusetts, USA and his colleagues present Metafluidics, an open-source, community-driven repository that hosts digital design files, assembly specifications, and open-source software to enable users to build, configure, and operate a microfluidic device. They use Metafluidics to share designs and fabrication instructions for both a microfluidic ring-mixer device and a 32-channel tabletop microfluidic controller. This device and controller are applied to build genetic circuits using standard DNA assembly methods including ligation, Gateway, Gibson, and Golden Gate. Metafluidics is intended to enable a broad community of engineers, DIY enthusiasts, and other nontraditional participants with limited fabrication skills to contribute to microfluidic research.

2. Engineered Cpf1 variants with altered PAM specificities.

The RNA-guided endonuclease Cpf1 is a promising tool for genome editing in eukaryotic cells. However, the utility of the commonly used Acidaminococcus sp. BV3L6 Cpf1 (AsCpf1) and Lachnospiraceae bacterium ND2006 Cpf1 (LbCpf1) is limited by their requirement of a TTTV protospacer adjacent motif (PAM) in the DNA substrate. To address this limitation, Linyi Gao at Broad Institute of MIT and Harvard in Massachusetts, USA and his colleagues performed a structure-guided mutagenesis screen to increase the targeting range of Cpf1. They engineered two AsCpf1 variants carrying the mutations S542R/K607R and S542R/K548V/N552R, which recognize TYCV and TATV PAMs, respectively, with enhanced activities in vitro and in human cells. Genome-wide assessment of off-target activity using BLISS indicated that these variants retain high DNA-targeting specificity, which they further improved by introducing an additional non-PAM-interacting mutation. Introducing the identified PAM-interacting mutations at their corresponding positions in LbCpf1 similarly altered its PAM specificity. Together, these variants increase the targeting range of Cpf1 by approximately threefold in human coding sequences to one cleavage site per ~11 bp.

3. Single-cell genome sequencing at ultra-high-throughput with microfluidic droplet barcoding.

The application of single-cell genome sequencing to large cell populations has been hindered by technical challenges in isolating single cells during genome preparation. Here Freeman Lan at University of California in California, USA and his colleagues present single-cell genomic sequencing (SiC-seq), which uses droplet microfluidics to isolate, fragment, and barcode the genomes of single cells, followed by Illumina sequencing of pooled DNA. They demonstrate ultra-high-throughput sequencing of >50,000 cells per run in a synthetic community of Gram-negative and Gram-positive bacteria and fungi. The sequenced genomes can be sorted in silico based on characteristic sequences. They use this approach to analyze the distributions of antibiotic-resistance genes, virulence factors, and phage sequences in microbial communities from an environmental sample. The ability to routinely sequence large populations of single cells will enable the de-convolution of genetic heterogeneity in diverse cell populations.

4. Engineered bacteria can function in the mammalian gut long-term as live diagnostics of inflammation.

Bacteria can be engineered to function as diagnostics or therapeutics in the mammalian gut but commercial translation of technologies to accomplish this has been hindered by the susceptibility of synthetic genetic circuits to mutation and unpredictable function during extended gut colonization. Here, David T Riglar at Harvard Medical School in Massachusetts, USA and his colleagues report stable, engineered bacterial strains that maintain their function for 6 months in the mouse gut. They engineered a commensal murine Escherichia coli strain to detect tetrathionate, which is produced during inflammation. Using their engineered diagnostic strain, which retains memory of exposure in the gut for analysis by fecal testing, they detected tetrathionate in both infection-induced and genetic mouse models of inflammation over 6 months. The synthetic genetic circuits in the engineered strain were genetically stable and functioned as intended over time. The durable performance of these strains confirms the potential of engineered bacteria as living diagnostics.

5. Rapid cloning of genes in hexaploid wheat using cultivar-specific long-range chromosome assembly.

Cereal crops such as wheat and maize have large repeat-rich genomes that make cloning of individual genes challenging. Moreover, gene order and gene sequences often differ substantially between cultivars of the same crop species. A major bottleneck for gene cloning in cereals is the generation of high-quality sequence information from a cultivar of interest. In order to accelerate gene cloning from any cropping line, Anupriya Kaur Thind at University of Zurich in Zurich, Switzerl and and his colleagues report ‘targeted chromosome-based cloning via long-range assembly’ (TACCA). TACCA combines lossless genome-complexity reduction via chromosome flow sorting with Chicago long-range linkage to assemble complex genomes. They applied TACCA to produce a high-quality (N50 of 9.76 Mb) de novo chromosome assembly of the wheat line CH Campala Lr22a in only 4 months. Using this assembly they cloned the broad-spectrum Lr22a leaf-rust resistance gene, using molecular marker information and ethyl methanesulfonate (EMS) mutants, and found that Lr22a encodes an intracellular immune receptor homologous to the Arabidopsis thaliana RPM1 protein.

2017年6月22日星期四

Anti-Plant Actin Mouse Monoclonal Antibody (3T3) becomes the latest addition to the Abbkine family

Abbkine Scientific Co. Ltd is known for making quality life science products and tools and it recently announced the official launch of its new antibody – the Anti-Plant Actin Mouse Monoclonal Antibody (3T3).

The antibody otherwise known as AT3G12110 antibody is a Plant Actin Antibody, which is an essential component of cell cytoskeleton. The substance also plays a critical role in the streaming of cytoplasmic, determination of cell shape, cell division and extension growth.

The product is available in a liquid solution and hosted by mouse hence, Plant Actin Mouse mAb. The antibody is also a Recombinant Protein immunogen, with plant reactivity. The antibody like many of its other counterparts is affinity-purified from mouse ascites using specific immunogen by affinity-chromatography.

The Anti-Plant Actin Mouse Monoclonal Antibody (3T3) is made solely for research purpose and not intended for clinical or human use. It can also be stored for as long as one year at -20°C from date of shipment.

Optimal working dilutions for the Anti-Plant Actin Mouse Monoclonal Antibody (3T3) should be determined by the investigator after experiments. However, the suggested starting dilutions are WB 1:2000-5000.

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About Abbkine Scientific

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