Fluorescent nanoparticles (FNPs) have been found to be useful as visualization tools for biological sensing, probing, imaging, and monitoring. Applied to targeted cancer cell imaging, FNPs are highly desirable for early stage cancer diagnosis and treatment. However, the light emission from most of the FNPs reported is severely limited because of the aggregation-caused quenching (ACQ) effect. Herein, we present highly emissive inorganic-organic nanoparticles with core-shell structures for targeted cancer cell imaging. Coated with a folate-functionalized silica shell, 9,10-distyrylanthracene (DSA) fluorogens with aggregation-induced emission (AIE) properties served as the fluorescent core, affording folate-functionalized fluorescent silica nanoparticles (FFSNPs) with a high fluorescence quantum yield (up to 20%). The FFSNPs are of small size (diameter ~60 nm), monodispersed, stable in aqueous suspension, and pose little toxicity to living cells and thus can be utilized for targeted HeLa cell imaging. In addition, the FFSNPs are mesoporous and therefore can potentially be used as vehicles for controlled, externally activated release of anticancer drugs.

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MicroRNAs (miRNAs) are small non-coding endogenous RNA molecules that down-regulate the expression of target genes in a sequence-dependent manner. Recent studies indicated that miRNAs are mechanistically involved in the regulation of the mammalian corpus luteum (CL). However, few studies have profiled the different miRNA expression patterns in bovine non-regressed and regressed CL. In this study, miRNA microarray was employed to investigate the different miRNA expression patterns in bovine CL. Among the 13 differentially expressed miRNAs, seven were preferentially expressed in non-regressed CL, while six miRNAs were more highly expressed in regressed CL. Real-time RT-PCR was used to validate the microarray results. Mir-378 miRNA, known to be associated with apoptosis, was 8.54-fold (P < 0.01) up-regulated in non-regressed CL, and the interferon gamma receptor 1 (IFNGR1) gene, which potentially plays a role in apoptosis of the luteal cell, was predicted to be the target of mir-378. The results of real-time RT-PCR of mir-378 and western blot analysis of the IFNGR1 protein at different stages of CL development showed that mir-378 decreased the expression of IFNGR1 protein but not IFNGR1 mRNA. Taken together, our data support a direct role for miRNA in apoptosis of bovine CL.

Background The natural hosts of Shigella are typically humans and other primates, but it has been shown that the host range of Shigella has expanded to many animals. Although Shigella is becoming a major threat to animals, there is limited information on the genetic background of local strains. The purpose of this study was to assess the presence of virulence factors and the molecular characteristics of S. flexneri isolated from calves with diarrhea. Results Fifty-four S. flexneri isolates from Gansun, Shanxi, Qinghai, Xinjiang and Tibet obtained during 2014 to 2016 possessed four typical biochemical characteristics of Shigella. The prevalences of ipaH, virA, ipaBCD, ial, sen, set1A, set1B and stx were 100 %, 100 %, 77.78 %, 79.63 %, 48.15 %, 48.15 and 0 %, respectively. Multilocus variable number tandem repeat analysis (MLVA) based on 8 variable number of tandem repeat (VNTR) loci discriminated the isolates into 39 different MLVA types (MTs), pulsed field gel electrophoresis (PFGE) based on NotI digestion divided the 54 isolates into 31 PFGE types (PTs), and multilocus sequence typing (MLST) based on 15 housekeeping genes differentiated the isolates into 7 MLST sequence types (STs). Conclusions The findings from this study enrich our knowledge of the molecular characteristics of S. flexneri collected from calves with diarrhea, which will be important for addressing clinical and epidemiological issues regarding shigellosis.

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We previously reported that numerous naturally occurring genetic mutations in the 5'-upstream regulatory region (5'-URR) of the bovine follicle-stimulating hormone beta-subunit gene (FSHB) were associated with reduced serum follicle-stimulating hormone (FSH) levels, poor-quality semen and low fertility in bulls. In addition, two different FSHB mRNA transcripts resulting from the linked mutations of genomic DNA were discovered in mutation-bearing bull pituitaries. Here, using electrophoretic mobility shift assay, we identified c.-1539_-1538delGGinsTTAACT mutations in the 5'-URR that generated a novel cis-regulatory element in bovine FSHB. Moreover, this novel element seemed to play a role in repressing FSHB transcription based on a promoter activity analysis in LβT2 gonadotrope cells. Quantitative assays of FSHB mRNA in the bovine pituitaries suggested that the levels of FSHB wild-type transcripts in the mutation-bearing bulls were significantly lower (P < 0.05) than in those of bulls without FSHB genetic mutations and that the levels of FSHB-mutated transcripts were significantly lower (P < 0.05) than that of wild-type transcripts in the mutation-bearing bulls. Altogether, our results suggest that decreased serum FSH levels and male fertility in bulls with the c.-1539_-1538delGGinsTTAACT mutation likely result from the alteration of cis-regulatory elements and induction of FSHB transcription.

Background: Antibiotic resistance genes (ARGs) have become recognized contaminants and pose a high public health risk. The animal gut microbiota is a reservoir of ARGs, but the knowledge of the origin and dissemination of ARGs remains unclear. Methods: 30 of the fecal samples were obtained from bovine and were immediately frozen in liquid nitrogen. Total metagenomic DNA was extracted by cetyltrimethylammonium bromide (CTAB) method and sequenced by Illumina HiSeq X Ten platform. After quality control and assembled, the sequence were annotated by NR, CARD and IS nder. Statistical analysis was performed using SPSS 19.0.Results: A total of 42 ARG types were detected by annotating the metagenomic sequencing data from the Comprehensive Antibiotic Resistance Database (CARD). We found that the diversity and abundance of ARGs in individual yaks were signi cantly lower than those in dairy and beef cattle. The results of heat map and single-nucleotide polymorphism (SNP) clustering suggest that ARGs from dairy and beef cattle are more similar, while those from yaks cluster separately. Conclusion:The long-term use of antibiotics may contribute to this difference, suggesting that antibiotic consumption is the main cause of ARG prevalence. Furthermore, abundant insertions and integrations were also found in this study, signifying a strong potential for horizontal transfer of ARGs among microbes, especially pathogens.

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