DBCO-PEG4-Desthiobiotin is a PEG linker containing a desthiobiotin group and a DBCO functional group. Desthiobiotin is used for affinity-based applications such as pull-down assays or for ligating with streptavidin proteins while DBCO is a click chemistry handle that quickly reacts with azide groups on target molecules. Desthiobiotin is a sulfur-free analogue of biotin which binds streptavidin with slightly less strength than biotin, which provides it with a soft-release characteristic that is useful for in pull-down assays by minimizing co-elution with endogenous biotinylated molecules. The inclusion of a PEG linker in this molecule improves its aqueous solubility.
Detail
DBCO-PEG4-Desthiobiotin is a PEG linker containing a desthiobiotin group and a DBCO functional group. Desthiobiotin is used for affinity-based applications such as pull-down assays or for ligating with streptavidin proteins while DBCO is a click chemistry handle that quickly reacts with azide groups on target molecules. Desthiobiotin is a sulfur-free analogue of biotin which binds streptavidin with slightly less strength than biotin, which provides it with a soft-release characteristic that is useful for in pull-down assays by minimizing co-elution with endogenous biotinylated molecules. The inclusion of a PEG linker in this molecule improves its aqueous solubility.
Gel images of different ranges of library size selection. Sheared human genomic DNA was used as input.
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Library size selection is an enrichment of a specific range of library sizes for NGS library preparations. The NGS library preparation is related to the quality of the sequencing data. Precise NGS library size selection can increase sequencing efficiency, improve data quality, and reduce costs.
There are two types of sequencing technologies: short-read sequencing and long-read sequencing. Short-read sequencing uses DNA libraries that contain small insert DNA fragments of similar sizes, usually several hundred base pairs. The sequencing efficiency can be improved if the DNA size selection is in the right range. Cat.# 20104S and 20104L are the best kits for NGS library size selection of illumina paired-end 100 (PE100) sequencing with 100-200 bp library inserts; Cat.# 20105S and 20105L are the best kits for NGS library size selection of illumina paired-end 150 (PE150) sequencing with 150-300 bp library inserts; and Cat.# 20106S and 20106L are the best kits for NGS library size selection of illumina paired-end 300 (PE300) sequencing with 300-600 bp library inserts.
Long-read sequencing uses a large DNA fragment as input and makes very long reads. Usually, library size selection is preferred to remove smaller fragments. Cat.# 20110S and 20110L are the best kits for long-read sequencing size selection with DNA sizes >5 kb, and Cat.# 20111S and 20111L are the best kits for long-read sequencing size selection with DNA sizes >10 kb.
The magnetic beads, or SPRI (Solid Phase Reversible Immobilization) beads, is well used for the purification of DNA due to their reversible DNA binding. The NGS library can be size-selected by the magnetic beads or SPRI beads. The properties of the magnetic beads can be changed for a specific range of DNA binding. The contaminants and other unwanted components in the libraries can also be removed during size selection.
Specific ranges of NGS libraries can be selected using magnetic beads with different buffer compositions. The first DNA-beads binding step, also called the right-side clean-up, removes large NGS library fragments. The large NGS library fragments that bind to the beads are discarded with the beads pellet. The desired NGS library fragments in the supernatant are transferred to a new well, and new beads are added to the supernatant for the second beads-DNA binding, also called the left-side clean-up. After the rinsing step, the NGS library fragments with the dual selection are eluted in water or an appropriate buffer. The magnetic beads method has great advantages over time-consuming column purification and tedious gel-based purification.
NGS library size selection with dual clean-ups.
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Library size selection for long-read sequencing only requires a single clean-up. In this case, only the large library fragments are bound to the beads, while other small library fragments are discarded with the supernatant. The selected larger library fragments are eluted in water or an appropriate buffer after the rinsing step.
NGS library size selection with single clean-up for >5 kb and >10 kb libraries.
Usages： For determination of coliform confirmatory test for multi-tube fermentation.
Principle: Peptone provide carbon and nitrogen sources; lactose as fermentable sugars; ox bile powder and brilliant green inhibit the non-Enterobacteriaceae.
Formulation (per liter): Peptone: 10g Lactose: 10g Ox bile powder: 20g Brilliant green: 0.0133g Final pH7.2 ± 0.2
How to use: 1.Suspend 40g of the product, add 1 L of distilled water, stirring heated to boiling until completely dissolved, packed in a test tube with a small inverted tube, autoclave at 121 ℃ for 15min, cool to room temperature and set aside. 2.Sample handling and dilution. Slightly. 3.Transplanted LST broth tube to brilliant green lactose bile broth tube by using a inoculating loop. 4.the tube was placed in an incubator culture at 36 ± 1 ℃ for 24h. 5.Observe the results. Press production trachea number, check table report MPN MPN value per gram (mL) sample of coliform bacteria.
Quality control: Quality control strains were inoculated and culuture at 36 ± 1 ℃ for 24h ,results are as follows: Bacterial Name Bacterial No. Growth Status Gassing Escherichia coli ATCC25922 good +
Salmonella typhimurium CMCC (B) 50115 good —
Staphylococcus aureus ATCC6538 inhibited —
Storage: Store in a dark, cool and dry place, tighten the cap immediately after use. Storage period of three years.
Programmed Death-Ligand 1 (PD-L1), also known as CD274 or B7 Homolog 1 (B7-H1), is a transmembrane protein involved in suppressing the immune system and rendering tumor cells resistant to CD8 T cell-mediated lysis through binding of the Programmed Death-1 (PD-1) receptor. Overexpression of PD-L1 may allow cancer cells to evade the actions of the host immune system. In renal cell carcinoma, upregulation of PD-L1 has been linked to increased tumor aggressiveness and risk of death, and, in ovarian cancer, higher expression of this protein has lead to significantly poorer prognosis. PD-L1 has also been linked to systemic lupus erythematosus and cutaneous melanoma. When considered in adjunct with CD8 tumor-infiltrating lymphocyte density, expression levels of PD-L1 may be a useful predictor of multiple cancer types, including stage III non-small cell lung cancer, hormone receptor negative breast cancer, and sentinel lymph node melanoma.
