Novel Single-Cell Analysis Platform Based on a Solid-State Zinc-Coadsorbed Carbon Quantum Dots Electrochemiluminescence Probe for the Evaluation of CD44 Expression on Breast Cancer Cells

A novel single-cell analysis platform was fabricated using solid-state zinc-coadsorbed carbon quantum dot (ZnCQDs) nanocomposites as an electrochemiluminescence (ECL) probe for the detection of breast cancer cells and evaluation of the CD44 expression level. Solid-state ZnCQDs nanocomposite probes were constructed through the attachment of ZnCQDs to gold nanoparticles and then the loading of magnetic beads to amplify the ECL signal, exhibiting a remarkable 120-fold enhancement of the ECL intensity. Hyaluronic acid (HA)-functionalized solid-state probes were used to label a single breast cancer cell by the specific recognition of HA with CD44 on the cell surface, revealing more stable, sensitive, and effective tagging in comparison with the water-soluble CQDs. This strategy exhibited a good analytical performance for the analysis of MDA-MB-231 and MCF-7 single cells with linear range from 1 to 18 and from 1 to 12 cells, respectively. Furthermore, this single-cell analysis platform was used for evaluation of the CD44 expression level of these two cell lines, in which the MDA-MB-231 cells revealed a 2.8–5.2-fold higher CD44 expression level. A total of 20 single cells were analyzed individually, and the distributions of the ECL intensity revealed larger variations, indicating the high cellular heterogeneity of the CD44 expression level on the same cell line. The as-proposed single-cell analysis platform might provide a novel protocol to effectively study the individual cellular function and cellular heterogeneity

Table_1.DOCX

<p>The aim of this study was to characterize the subtypes and virulence profiles of 69 Staphylococcus aureus isolates obtained from retail ready-to-eat food in China. The isolates were analyzed using multilocus sequence typing (MLST) and polymerase chain reaction (PCR) analysis of important virulence factor genes, including the staphylococcal enterotoxin (SE) genes (sea, seb, sec, sed, see, seg, seh, sei, sej), the exfoliative toxin genes (eta and etb), the toxic shock syndrome toxin-1 gene (tst), and the Panton-Valentine leucocidin-encoding gene (pvl). The isolates encompassed 26 different sequence types (STs), including four new STs (ST3482, ST3484, ST3485, ST3504), clustered in three clonal complexes and 17 singletons. The most prevalent STs were ST1, ST6, and ST15, constituting 34.8% of all isolates. Most STs (15/26, 57.7%) detected have previously been associated with human infections. All 13 toxin genes examined were detected in the S. aureus isolates, with 84.1% of isolates containing toxin genes. The three most prevalent toxin genes were seb (36.2%), sea (33.3%), and seg (33.3%). The classical SE genes (sea–see), which contribute significantly to staphylococcal food poisoning (SFP), were detected in 72.5% of the S. aureus isolates. In addition, pvl, eta, etb, and tst were found in 11.6, 10.1, 10.1, and 7.2% of the S. aureus isolates, respectively. Strains ST6 carrying sea and ST1 harboring sec-seh enterotoxin profile, which are the two most common clones associated with SFP, were also frequently detected in the food samples in this study. This study indicates that these S. aureus isolates present in Chinese ready-to-eat food represents a potential public health risk. These data are valuable for epidemiological studies, risk management, and public health strategies.</p

Gene deletion profiles and types for the 13 <i>Salmonella</i>1,4,[5],12:i:- isolates.

<p>Gene deletion profiles and types for the 13 <i>Salmonella</i><u>1</u>,4,[5],12:i:- isolates.</p

Prevalence (%) of the virulence genes by serotype.

<p>Prevalence (%) of the virulence genes by serotype.</p

Antimicrobial resistance patterns of <i>Salmonella</i>1,4,[5],12:i:- and <i>Salmonella</i> Typhimurium isolates.

<p>^aASSuT resistance phenotype (ampicillin-streptomycin-sulfonamides-tetracycline);</p><p>^bACSSuT resistance phenotype (ampicillin-chloramphenicol-streptomycin-sulfonamides-tetracycline).</p><p>Antimicrobial resistance patterns of <i>Salmonella</i><u>1</u>,4,[5],12:i:- and <i>Salmonella</i> Typhimurium isolates.</p

Virulotyping: most commonly detected haplotypes.

<p>^aIdentical haplotypes.</p><p>Virulotyping: most commonly detected haplotypes.</p

Prevalence and Characterization of Monophasic <i>Salmonella</i> Serovar 1,4,[5],12:i:- of Food Origin in China

<div><p><i>Salmonella enterica</i> subsp. <i>enterica</i> serovar <u>1</u>,4,[5],12:i:- is a monophasic variant of <i>Salmonella</i> Typhimurium, which has recently been recognized as an emerging cause of infection worldwide. This bacterium has also ranked among the four most frequent serovars causing human salmonellosis in China. However, there are no reports on its contamination in Chinese food. Serotyping, polymerase chain reaction, antibiotic resistance, virulotyping, and multilocus sequence typing (MLST) assays were used to investigate the prevalence of this serological variant in food products in China, and to determine phenotypic and genotypic difference of monophasic isolates and <i>Salmonella</i> Typhimurium isolated over the same period. <i>Salmonella</i><u>1</u>,4,[5],12:i:- was prevalent in various food sources, including beef, pork, chicken, and pigeon. The study also confirmed the high prevalence (53.8%) of resistance to ampicillin, streptomycin, sulfonamides, and tetracycline in <i>Salmonella</i><u>1</u>,4,[5],12:i:-, which was higher than that in <i>Salmonella</i> Typhimurium. Moreover, <i>Salmonella</i><u>1</u>,4,[5],12:i:- isolates in our study were different from <i>Salmonella</i> Typhimurium isolates by the absence of three plasmid-borne genes (<i>spvC</i>, <i>pefA</i>, and <i>rck</i>) and the presence of <i>gipA</i> in all isolates. All <i>Salmonella</i><u>1</u>,4,[5],12:i:- isolates demonstrated MLST pattern ST34. Genomic deletions within the <i>fljBA</i> operon and surrounding genes were only found in <i>Salmonella</i><u>1</u>,4,[5],12:i:- isolates, with all isolates containing a deletion of <i>fljB</i>. However, <i>hin</i> and <i>iroB</i> were identified in all <i>Salmonella</i><u>1</u>,4,[5],12:i:- isolates. Three different deletion profiles were observed and two of them were different from the reported <i>Salmonella</i><u>1</u>,4,[5],12:i:- clones from Spain, America, and Italy, which provided some new evidence on the independent evolution of the multiple successful monophasic clones from <i>Salmonella</i> Typhimurium ancestors. This study is the first report of <i>Salmonella</i><u>1</u>,4,[5],12:i:- in food products from China. The data are more comprehensive and representative, providing valuable information for epidemiological studies, risk management, and public health strategies.</p></div

Functional-Group Specific Aptamers Indirectly Recognizing Compounds with Alkyl Amino Group

Aptamers are usually generated against a specific molecule. Their high selectivity makes them only suitable for studying specific targets. Since it is nearly impossible to generate aptamers for every molecule, it can be of great interest to select aptamers recognizing a common feature of a group of molecules in many applications. In this paper, we describe the selection of aptamers for indirect recognition of alkyl amino groups. Because amino groups are small and positive charged, we introduced a protection group, <i>p</i>-nitrobenzene sulfonyl (<i>p</i>-nosyl) to convert them into a form suitable for aptamer selection. Taking N^ε-<i>p</i>-nosyl-l-lysine (PSL) as a target, we obtained a group of aptamers using the SELEX technique. Two optimized aptamers, M6b-M14 and M13a exhibit strong affinity to PSL with the <i>K</i>_d values in the range of 2–5 μM. They also show strong affinity to other compounds containing <i>p</i>-nosyl-protected amino groups except those also possessing an α-carboxyl group. Both aptamers adopt an antiparallel G-quadruplex structure when binding to targets. An aptamer beacon based on M6b-M14 showed good selectivity toward the reaction mixture of <i>p</i>-nosyl-Cl and alkyl amino compounds, and could recognize lysine from amino acid mixtures indirectly, suggesting that aptamers against a common moiety of a certain type of molecules can potentially lead to many new applications. Through this study, we have demonstrated the ability to select aptamers for a specific part of an organic compound, and the chemical conversion approach may prove to be valuable for aptamer selection against molecules that are generally difficult for SELEX

DataSheet_1_Severe persistent mycobacteria antigen stimulation causes lymphopenia through impairing hematopoiesis.docx

Miliary tubersculosis (TB), an acute systemic blood disseminated tuberculosis mainly caused by Mycobacterium tuberculosis (M. tuberculosis), can cause signs of lymphopenia in clinical patients. To investigate whether/how persistent mycobacteria antigen stimulation impairs hematopoiesis and the therapeutic effect of interleukin-7 (IL-7), a mouse model of Mycobacterium Bovis Bacillus Calmette-Guérin (BCG) intravenous infection with/without an additional stimulation with M. tuberculosis multi-antigen cocktail containing ESAT6-CFP10 (EC) and Mtb10.4-HspX (MH) was established. Consistent with what happened in miliary TB, high dose of BCG intravenous infection with/without additional antigen stimulation caused lymphopenia in peripheral blood. In which, the levels of cytokines IFN-γ and TNF-α in serum increased, and consequently the expression levels of transcription factors Batf2 and IRF8 involved in myeloid differentiation were up-regulated, while the expression levels of transcription factors GATA2 and NOTCH1 involved in lymphoid commitment were down-regulated, and the proliferating activity of bone marrow (BM) lineage- c-Kit+ (LK) cells decreased. Furthermore, recombinant Adeno-Associated Virus 2-mediated IL-7 (rAAV2-IL-7) treatment could significantly promote the elevation of BM lymphoid progenitors. It suggests that persistent mycobacteria antigen stimulation impaired lymphopoiesis of BM hematopoiesis, which could be restored by complement of IL-7.</p

Uranium Adsorption Tests of Amidoxime-Based Ultrahigh Molecular Weight Polyethylene Fibers in Simulated Seawater and Natural Coastal Marine Seawater from Different Locations

Uranium recovery from seawater was investigated in simulated seawater in the laboratory and in natural seawater from the coasts of China with different amidoxime-based (AO) ultrahigh molecular weight polyethylene (UHMWPE) fibers. The capacities of adsorbents AO-UHMWPE-1 and -2 were 4.54 and 2.41 mg U/g-adsorbent, respectively, after 24 h of adsorption in the simulated seawater with 330 ppb U. Their capacities were 2.93 and 1.95 mg U/g-adsorbent, respectively, after 42 days of adsorption in simulated seawater flow-through experiments with 3.3 ppb U. However, because of sediment and marine organism contamination, the capacities were 0.25 and 0.04 mg U/g-adsorbent, respectively, after 68 days of adsorption in natural seawater in Xiamen. The capacity of AO-UHMWPE-7 was 1.41 mg U/g-adsorbent after 15 days of adsorption in natural seawater in Daishan. The average capacity of AO-UHMWPE-7 was 1.50 mg U/g-adsorbent, which was 18 times greater than that for V after 15 days of adsorption in natural seawater in Daishan. Results indicated that there were many factors affecting the adsorption capacity of uranium. In addition to the character of the adsorbent, including degree of grafting, functional group density, and AO conversion ratio, the marine hydrological conditions, such as temperature, flow velocity, turbidity, etc., are also crucially important for uranium extraction from seawater