Photoluminescent Gold Nanoclusters as Sensing Probes for Uropathogenic Escherichia coli

Glycan-bound nanoprobes have been demonstrated as suitable sensing probes for bacteria containing glycan binding sites. In this study, we demonstrated a facile approach for generating glycan-bound gold nanoclusters (AuNCs). The generated AuNCs were used as sensing probes for corresponding target bacteria. Mannose-capped AuNCs (AuNCs@Mann) were generated and used as the model sensors for target bacteria. A one-step synthesis approach was employed to generate AuNCs@Mann. In this approach, an aqueous solution of tetrachloroauric acid and mannoside that functionized with a thiol group (Mann-SH) was stirred at room temperature for 48 h. The mannoside functions as reducing and capping agent. The size of the generated AuNCs@Mann is 1.95±0.27 nm, whereas the AuNCs with red photoluminescence have a maximum emission wavelength of ∼630 nm (λ_excitation = 375 nm). The synthesis of the AuNCs@Mann was accelerated by microwave heating, which enabled the synthesis of the AuNCs@Mann to complete within 1 h. The generated AuNCs@Mann are capable of selectively binding to the urinary tract infection isolate Escherichia coli J96 containing the mannose binding protein FimH expressed on the type 1 pili. On the basis of the naked eye observation, the limit of detection of the sensing approach is as low as ∼2×10⁶ cells/mL.     

Modified McKeown Minimally Invasive Esophagectomy for Esophageal Cancer: A 5-Year Retrospective Study of 142 Patients in a Single Institution

Background

To achieve decreased invasiveness and lower morbidity, minimally invasive esophagectomy (MIE) was introduced in 1997 for localized esophageal cancer. The combined thoracoscopic-laparoscopic esophagectomy (left neck anastomosis, defined as the McKeown MIE procedure) has been performed since 2007 at our institution. From 2007 to 2011, our institution subsequently evolved as a high-volume MIE center in China. We aim to share our experience with MIE, and have evaluated the outcomes of 142 patients.

Methods

We retrospectively reviewed 142 consecutive patients who had presented with esophageal cancer undergoing McKeown MIE from July 2007 to December 2011. The procedure, surgical outcomes, disease-free and overall survival of these cases were assessed.

Results

The average total procedure time was 270.5±28.1 min. The median operation time for thoracoscopy was 81.5±14.6 min and for laparoscopy was 63.8±9.1 min. The average blood loss associated with thoracoscopy was 123.8±39.2 ml, and for laparoscopic procedures was 49.9±14.3 ml. The median number of lymph nodes retrieved was 22.8. The 30 day mortality rate was 0.7%. Major surgical complications occurred in 24.6% and major non-surgical complications occurred in 18.3% of these patients. The median DFS and OS were 36.0±2.6 months and 43.0±3.4 months respectively.

Conclusions

Surgical and oncological outcomes following McKeown MIE for esophageal cancer were acceptable and comparable with those of open-McKeown esophagectomy. The procedure was both feasible and safe – properties that can be consolidated by experience.     

FLZ Alleviates the Memory Deficits in Transgenic Mouse Model of Alzheimer’s Disease via Decreasing Beta-Amyloid Production and Tau Hyperphosphorylation

Alzheimer’s disease (AD) is the most common cause of dementia worldwide and mainly characterized by the aggregated β-amyloid (Aβ) and hyperphosphorylated tau. FLZ is a novel synthetic derivative of natural squamosamide and has been proved to improve memory deficits in dementia animal models. In this study, we aimed to investigate the mechanisms of FLZ’s neuroprotective effect in APP/PS1 double transgenic mice and SH-SY5Y (APPwt/swe) cells. The results showed that treatment with FLZ significantly improved the memory deficits of APP/PS1 transgenic mice and decreased apoptosis of SH-SY5Y (APPwt/swe) cells. FLZ markedly attenuated Aβ accumulation and tau phosphorylation both in vivo and in vitro. Mechanistic study showed that FLZ interfered APP processing, i.e., FLZ decreased β-amyloid precursor protein (APP) phosphorylation, APP-carboxy-terminal fragment (APP-CTF) production and β-amyloid precursor protein cleaving enzyme 1 (BACE1) expression. These results indicated that FLZ reduced Aβ production through inhibiting amyloidogenic pathway. The mechanistic study about FLZ’s inhibitory effect on tau phosphorylation revealed t the involvement of Akt/glycogen synthase kinase 3β (GSK3β) pathway. FLZ treatment increased Akt activity and inhibited GSK3β activity both in vivo and in vitro. The inhibitory effect of FLZ on GSK3β activity and tau phosphorylation was suppressed by inhibiting Akt activity, indicating that Akt/GSK3β pathway might be the possible mechanism involved in the inhibitory effect of FLZ on tau hyperphosphorylation. These results suggested FLZ might be a potential anti-AD drug as it not only reduced Aβ production via inhibition amyloidogenic APP processing pathway, but also attenuated tau hyperphosphoylation mediated by Akt/GSK3β.     

RhoGAPs Attenuate Cell Proliferation by Direct Interaction with p53 Tetramerization Domain

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Construction of a genetic linkage map in Fenneropenaeus chinensis using SNP markers

Genetic linkage maps of Fenneropenaeus chinensis were constructed using a “double pseudo-testcross” strategy with 200 single nucleotide polymorphisms (SNPs) markers. This study represents the first SNP genetic linkage map for F. chinensis. The parents and F ₁ progeny of 100 individuals were used as mapping populations. 21 genetic linkage groups in the male and female maps were identified. The male linkage map was composed of 115 loci and spanned 879.7 cM, with an average intermarker spacing of 9.4 cM, while the female map was composed of 119 loci and spanned 876.2 cM, with an average intermarker spacing of 8.9 cM. The estimated coverage of the linkage maps was 51.94% for the male and 53.77% for the female, based on two estimates of genome length. The integrated map contains 180 markers distributed in 16 linkage groups, and spans 899.3 cM with an average marker interval of 5.2 cM. This SNP genetic map lays the foundation for future shrimp genomics and genetic breeding studies, especially the discovery of gene or regions for economically important traits in Chinese shrimp.     

A comparative study of the atp9 gene between a cytoplasmic male sterile line and its maintainer line and further development of a molecular marker specific for male sterile cytoplasm in kenaf (Hibiscus cannabinus L.)

mtDNA was isolated from cytoplasmic male sterility (CMS) line P3A and its maintainer P3B of kenaf (Hibiscus cannabinus L.). The atp9 gene and its two flanking sequences were obtained using homology cloning and high-efficiency thermal asymmetric interlaced PCR methods. The coding sequences showed only two base pairs difference between the CMS and its maintainer, and shared a homology of over 87 % with atp9 genes from other species in GenBank. However, when comparing the flanking sequences, a 47-bp deletion was characterized at the 3′ flanking sequence of atp9 in the CMS line. Quantitative PCR analysis indicated that the expression level of atp9 in the CMS line was 0.937-fold that of its maintainer. Furthermore, the respiratory rate of anthers in the CMS line was markedly lower than that of its maintainer. The results indicated that the 47-bp deletion at the 3′ flanking sequence of atp9 and/or down-regulated expression of the atp9 gene in the CMS line might be closely related to CMS in kenaf. To confirm whether the 47-bp deletion was specific to cytoplasm of male sterile lines, another 21 varieties were used for further analysis. The results showed that the 47-bp deletion was specific to male sterile cytoplasm (MSC) of kenaf. Based on these, a specific molecular marker was developed to distinguish the MSC from male fertile cytoplasm of kenaf.     

Slow rise of Ca2+ and slow release of reactive oxygen species are two cross-talked events important in tumour necrosis factor-α-mediated apoptosis

Tumour necrosis factor-α(TNF-α) was found to be a cell cycle-independent apoptogenic cytokine in cultured fibroblast L929 cells. This assertion is based on the observations (1) TNF-α increased the number of cells with hypo-diploid DNA in a time dependent manner as revealed by flow cytometry, and (2) TNF-α induced DNA fragmentation as resolved by agarose gel electrophoresis. When cells were exposed to TNF-α (50ng/ml), a slow rise in intracellular free Ca²⁺ level and a delayed increase in the production of reactive oxygen species (ROS) (both observed 3h after the addition of TNF-α) were observed in fluo-3 and furared or dichlorofluorescein loaded cells, respectively. Interestingly, challenge of cells with TNF-α in the presence of BAPTA/AM, an intracellular Ca²⁺ chelator, decreased the release of ROS. Removal of ROS by 4-hydroxy 2,2,6,6-tetra-methyl-piperidinooxy (4OH-TEMPO) blocked the TNF-α-mediated Ca²⁺ rise. Moreover, when cells were exposed to TNF-α with both 4OH-TEMPO and BAPTA/AM, more viable cells were found than from treatment with either BAPTA/AM or 4OH-TEMPO. These results suggest that ROS and cellular Ca²⁺ are two cross-talk messengers important in TNF-α-mediated apoptosis.     

The association between genetic damage in peripheral blood lymphocytes and polymorphisms of three glutathione S-transferases in Chinese workers exposed to 1,3-butadiene

1,3-Butadiene (BD) has been classified as a human carcinogen, group I; however, the relationship between polymorphisms of glutathione S-transferases that metabolize BD and chromosomal damage is not clear. The present study used sister chromatid exchange (SCE) and cytokinesis-block micronucleus (CBMN) assays to detect chromosomal damage in peripheral lymphocytes of 44 BD-exposed workers and 39 non-exposed healthy controls. PCR and PCR-RFLP were employed to detect three known glutathione S-transferase polymorphisms GSTT1, GSTM1, and GSTP1 (Ile105Val). The data demonstrated that the micronucleus (CBMN) frequency in BD-exposed workers was significantly higher than that in controls (frequency ratio (FR) = 1.48, 95% CI: 1.14–1.91, P < 0.01), and the CBMN frequency was higher in workers exposed to higher cumulative BD levels (FR = 1.70, 95% CI: 1.28–2.27, P < 0.01). However, differences in SCE frequency were not observed (FR = 1.14, 95% CI: 0.81–1.61, P > 0.05). Among exposed workers, chromosomal damage was related to BD exposure levels (FR = 1.35, 95% CI: 1.02–1.80, P < 0.05); age, older workers exhibited higher MN frequencies than younger workers (FR = 1.45, 95% CI: 1.14–1.84, P < 0.05); and years of work, those with more years of work exhibited higher MN frequencies than those with fewer years (FR = 1.40, 95% CI: 1.10–1.77, P < 0.05). Multivariate Poisson regression analysis showed that those who carried GSTM1 (?) (FR = 1.48, 95% CI: 1.14–1.92) or GSTT1 (?) (FR = 1.42, 95% CI: 1.10–1.83) genotypes, and especially those who carried both (FR = 2.10, 95% CI: 1.43–3.09) exhibited significantly higher MN frequencies than those carrying GSTM1 (+), GSTT1 (+) genotypes or their combination. The GSTP1 Val genotype did not affect MN frequency (P > 0.05). Our results suggested that higher levels of BD exposure in the workplace resulted in increased chromosomal damage, and that polymorphisms in GSTT1 and GSTM1 genes might modulate the genotoxic effects of BD exposure. Furthermore, the GSTT1 and GSTM1 polymorphisms exhibited an additive effect. Finally, urinary DHBMA was found to provide a biomarker that correlated with airborne BD levels.