Screening of bacteria for self-healing of concrete cracks and optimization of the microbial calcium precipitation process.

A novel high-throughput strategy was developed to determine the calcium precipitation activity (CPA) of mineralization bacteria used for self-healing of concrete cracks. A bacterial strain designated as H4 with the highest CPA of 94.8 % was screened and identified as a Bacillus species based on 16S rDNA sequence and phylogenetic tree analysis. Furthermore, the effects of certain influential factors on the microbial calcium precipitation process of H4 were evaluated. The results showed that lactate and nitrate are the best carbon and nitrogen sources, with optimal concentrations of approximately 25 and 18 mM, respectively. The H4 strain is able to maintain a high CPA in the pH range of 9.5-11.0, and a suitable initial spore concentration is 4.0 × 10(7) spores/ml. Moreover, an ambient Ca(2+) concentration greater than 60 mM resulted in a serious adverse impact not only on the CPA but also on the growth of H4, suggesting that the maintenance of the Ca(2+) concentration at a low level is necessary for microbial self-healing of concrete cracks.

Toxicity of metal oxide nanoparticles: mechanisms, characterization, and avoiding experimental artefacts.

Metal oxide nanomaterials are widely used in practical applications and represent a class of nanomaterials with the highest global annual production. Many of those, such as TiO2 and ZnO, are generally considered non-toxic due to the lack of toxicity of the bulk material. However, these materials typically exhibit toxicity to bacteria and fungi, and there have been emerging concerns about their ecotoxicity effects. The understanding of the toxicity mechanisms is incomplete, with different studies often reporting contradictory results. The relationship between the material properties and toxicity appears to be complex and diifficult to understand, which is partly due to incomplete characterization of the nanomaterial, and possibly due to experimental artefacts in the characterization of the nanomaterial and/or its interactions with living organisms. This review discusses the comprehensive characterization of metal oxide nanomaterials and the mechanisms of their toxicity.

Open-access colonoscopy: outcomes of referrals from the emergency department.

AIM: The study investigated the diagnostic outcome of colonoscopy referrals from the emergency department (ED) via an open-access system. METHOD: A retrospective cohort study over two years was performed on all patients under 65 years referred for open-access colonoscopy by the ED in a hospital with an annual ED attendance of 140,000. Patient characteristics and presenting symptoms were retrieved. Waiting times from presentation to colonoscopy were recorded. RESULTS: Over a 2-year period, 266 patients were referred, of whom 37 defaulted, leaving 229 patients who had a colonoscopy. The mean age was 48.3 ± 11.3 (SD) and the female/male ratio was 229/125. The most frequent presenting symptoms included: rectal bleeding (n = 142, 62%), change of bowel habit (n = 47, 20.5%) and abdominal pain (n = 40, 17.5%). The median waiting time from presentation to colonoscopy was 17 (range 1-69) days. A positive colonoscopic finding was recorded in 45.4%, including colorectal cancer in 12 (5.2%). CONCLUSION: The rate of a positive diagnoses from the ED-based colonoscopy referral service was comparable to that of the general Hong Kong population. This approach may help to reduce the waiting time for colonoscopy in a specialist colorectal clinic.

MiR-101 promotes nasopharyngeal carcinoma cell apoptosis through inhibiting Ras/Raf/MEK/ERK signaling pathway.

The article "MiR-101 promotes nasopharyngeal carcinoma cell apoptosis through inhibiting Ras/Raf/MEK/ERK signaling pathway, by R.-S. Wu, E.-H. Qiu, J.-J. Zhu, J.-R. Wang, H.-L. Lin, published in Eur Rev Med Pharmacol Sci 2018; 22(1): 150-157-DOI: 10.26355/eurrev_201801_14112-PMID: 29364482" has been withdrawn from the authors. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/14112.

Differential conservation of histone 2A variants between mammals and sea urchins.

The histone 2A proteins of the sea urchin Strongylocentrotus purpuratus are compared with those of the mouse. While the major H2As in these two organisms do not comigrate on two-dimensional gels, the sea urchin contains a protein that comigrates with the minor histone 2A variant H2A.Z from mammals. H2A.Z is of particular interest because its sequence homology with other H2As is quite low, and it is not phosphorylated as are other H2As. A comparison of the tryptic peptide patterns of several H2As from sea urchin blastulae and mouse L1210 cells show that, while the patterns of the H2A.Zs differ greatly from the patterns of the other H2As, the patterns of the mouse and sea urchin H2A.Zs are very similar. Since the H2A.Zs have only one or two peptides in common with the other H2As, the conservation of their sequence indicates that H2A.Zs have evolved under somewhat different selective pressures from other H2As. Unlike all the other sea urchin H2As whose syntheses either turn on or off during early development, H2A.Z seems to be synthesized continuously throughout this period.U

Cytoplasmic synthesis of nuclear proteins. Kinetics of accumulation of radioactive proteins in various cell fractions after brief pulses.

The synthesis of cytoplasmic and nuclear proteins has been studied in HeLa cells by examining the amount of radioactive protein appearing in the various subcellular fractions after labeling for brief periods. Due to the rapid equilibration of the amino acid pool, the total radioactivity in cytoplasmic protein increases linearly. The radioactivity observed in the cytoplasm is the sum of two components, the nascent proteins on the ribosomes and the completed proteins. At very short labeling times the specific activity of newly formed proteins found in the soluble supernatant fraction (completed protein) increases as the square of time, whereas the specific activity of the ribosomal fraction (nascent protein) reaches a plateau after 100 sec. The kinetics of accumulation of radioactive protein in the nucleus and the nucleolus is very similar to that of completed cytoplasmic protein, which suggests that the proteins are of similar origin. The rate of release and migration of proteins from the ribosomes into the nucleus requires less time than the synthesis of a polypeptide, which is about 80 sec. The uptake of label into nucleolar proteins is as rapid as the uptake of label into proteins of the soluble fraction of the cytoplasm, while nuclear proteins, including histones, tend to be labeled more slowly. The same results are obtained if protein synthesis is slowed with low concentrations of cycloheximide. The kinetics of incorporation of amino acids into various fractions of the cell indicates that the nucleus and the nucleolus contain few if any growing polypeptide chains, and thus do not synthesize their own proteins.

In situ hybridization to detect spatial gene expression in medaka.

A whole-animal tissue section in situ hybridization (ISH) system with radio-labeled probes was developed to detect differential gene expression among tissues of the small, oviparous teleost fish, Japanese medaka (Oryzias latipes). Because of its tissue- and gender-specific expression, gonadal aromatase (CYP19a) was selected as a model gene to demonstrate the potential of the system. The ISH system was validated with a 7d exposure to the model aromatase inhibitor, fadrozole. Fadrozole did not affect the magnitude of gene expression in testes, but significantly up-regulated CYP19a gene expression in ovaries. These results were confirmed with quantitative real-time-polymerase chain reaction (RT-PCR). Histological evaluation revealed that females exposed to 100microg/L fadrozole lacked mature oocytes. Male gonadal morphology was normal in all treatments. The ISH method developed in this study allowed tissue-specific resolution of gene expression in a whole animal model, as well as the ability to analyze cellular morphological detail in the same organism.

Development of a marine fish model for studying in vivo molecular responses in ecotoxicology.

A protocol for fixation and processing of whole adult marine medaka (Oryzias melastigma) was developed in parallel with in situ hybridization (ISH) and immunohistochemistry (IHC) for molecular analysis of in vivo gene and protein responses in fish. Over 200 serial sagittal sections (5microm) can be produced from a single adult medaka to facilitate simultaneous localization and quantification of gene-specific mRNAs and proteins in different tissues and subcellular compartments of a single fish. Stereological analysis (as measured by volume density, V(v)) was used to quantify ISH and IHC signals on tissue sections. Using the telomerase reverse transcriptase (omTERT) gene, omTERT and proliferating cell nuclear antigen (PCNA) proteins as examples, we demonstrated that it is possible to localize, quantify and correlate their tissue expression profiles in a whole fish system. Using chronic hypoxia (1.8+/-0.2 mgO(2)L(-1) for 3 months) as an environmental stressor, we were able to identify significant alterations in levels of omTERT mRNA, omTERT protein, PCNA (cell proliferation marker) and TUNEL (apoptosis) in livers of hypoxic O. melastigma (p<0.05). Overall, the results suggest that O. melastigma can serve as a model marine fish for assessing multiple in vivo molecular responses to stresses in the marine environment.

Persistent dizziness and nausea in patients receiving postoperative epidural pain control after living donor liver transplantation: case reports.

Dizziness and nausea are frequent problems among patients receiving patient-controlled epidural analgesia (PCEA) after major surgery. It is important to consider the various etiologies that might cause these adverse events, especially among patients who have undergone massive hepatic resection for living donor liver transplantation (LDLT). We have described 2 LDLT cases with persistent dizziness and nausea postoperatively despite several adjustments in PCEA management. Their symptoms were quickly relieved after suspension of PCEA medication. Our 2 cases of LDLT represented a unique setting for this type of complication.

Artificial vascular graft for inferior vena cava reconstruction in living donor liver transplantation: a case report.

Artificial grafts are not recommended because of the high incidence of thrombogenic effects. However, in some situations, such as emergency or when no vascular bank is available, an artificial graft must be used. We present a case in which a polytetrafluoroethyline graft was used as a conduit to reconstruct the retrohepatic vena cava severed during living donor liver transplantation (LDLT). A 48-year-old woman had end-stage primary biliary cirrhosis for 5 years received a right lobe liver graft from her son. The retrohepatic vena cava was divided and ligated in several sequences. The upper end of the severed retrohepatic vena cava retracted into the liver parenchyma. The lower end of the severed vena cava was distended, with multiple stitches. A 16-mm artificial graft was used as a conduit to replace the inferin vena cava for outflow reconstruction. The patient tolerated the complicated procedure well. No anticoagulant was used throughout the entire course. The patient has been well with excellent liver function after follow-up for more than 5 years. Magnetic resonance imaging and Doppler ultrasonographic studies showed good patency of the cava with no evidence of thrombosis. We suggest use of an artificial graft in living donor liver transplantation, in particular in urgent situations when autologous or allogeneic vessels are not available.

Induction, adaptation and recovery of lysosomal integrity in green-lipped mussel Perna viridis.

Biomarkers are generally applied to detect pollution in environmental monitoring. Such biological responses should accurately reflect the stress over time in a quantitative manner. As such, the initial and maximum responses induced by stress, as well as adaptation and recovery of these biomarkers, need to be fully understood or else erroneous false-negative or false-positive may be arrived. However, most of the biomarker studies only provided information on initially induced responses under different concentrations of toxicants, while biological adaptation and recovery were poorly known. In this study, the time required for induction, adaptation and recovery of lysosomal integrity in green-lipped mussel Perna viridis upon exposure to benzo[a]pyrene was investigated over a period of 62 days. Maximum induction occurred on day 6 when lysosomal integrity was significantly reduced by 51%, and no further change or adaptation was detected thereafter. When mussels were depurated in clean seawater after 18 days of exposure to benzo[a]pyrene, a gradual recovery was observed, with lysosomal integrity returning to its background level and showing a complete recovery after 20 days of depuration. Lysosomal integrity was significantly correlated with the body burden concentrations of benzo[a]pyrene and condition index of the mussels. The relatively fast induction (6 days) and recovery (20 days) without apparent adaptation suggested that lysosomal integrity in P. viridis can serve as a good biomarker in biomonitoring, as its response is not likely to generate both false-negative and false-positive results.

Spatio-temporal changes of marine macrobenthic community in sub-tropical waters upon recovery from eutrophication. II. Life-history traits and feeding guilds of polychaete community.

A two-year study was conducted in the vicinity of a harbour in sub-tropical Hong Kong, to examine the progress of recovery of macrobenthic community, based on analyses of both life-history traits and trophic guilds of polychaetes, upon cessation of organic pollution caused by sewage discharge. Seventy seven out of 83 species collected were classified under four ecological groups based on the life-history traits and sensitivity to organic gradients. The mean ATZI marine biotic index (AMBI) derived from these ecological groups showed spatial difference among the five sampling locations. In particular, the presence of different percentages of polychaete species from Groups III (unbalanced community) and IV (polluted community) suggested the presence of pollution stress in certain degree at all sampling locations. However, no significant temporal changes were noted over the study period. From all polychaete species identified, they were classified into 13 feeding guilds. The mean diversity of these feeding guilds at most of the sampling locations was significantly higher than that at one of the inside-harbour locations. The composition of feeding guilds was also significantly different spatially. At one of the inside-harbour locations, the dominant feeding guilds were motile/discretely motile surface deposit feeders with tentaculates or unarmed pharynx, and motile omnivores with jawed pharynx in the first year of study, but were replaced by motile, jawed carnivores in the second year of study. The increased proportion of carnivores over the study period can be seen as a sign of recovery in the community structure since abundance of predators is commonly higher in habitats with better environmental quality. The implications of using life-history traits and feeding guild analyses for benthic community are discussed.

Spatio-temporal changes of marine macrobenthic community in sub-tropical waters upon recovery from eutrophication. I. Sediment quality and community structure.

A two-year study was conducted in the vicinity of a harbour in sub-tropical Hong Kong, to examine the progress of improvement in sediment quality and recovery of macrobenthic community upon cessation of organic pollution caused by sewage discharge. Median sediment particle diameter (Mdphi) and levels of total organic carbon (TOC), total Kjeldahl nitrogen (TKN), ammonia-nitrogen (NH(3)-N) and total phosphorus (TP), as well as macrobenthic species composition and abundance were determined bi-monthly at three inside-harbour and two outside-harbour locations. At the two inside-harbour locations, significantly higher levels of TOC, TKN, NH(3)-N and TP in sediments were observed than the outside-harbour locations. However, no significant temporal change of nutrient levels was detected at all sampling locations during the two-year study, except a significant decrease in TKN and NH(3)-N levels at one outside-harbour location and a decline in NH(3)-N content at another outside-harbour location. Spatially, the highest in mean total species number, individual number, species diversity H' and lowest evenness J was found at one outside-harbour location, whereas the other four locations had relatively similar values. H' was negatively correlated with TOC, TKN, NH(3)-N and TP content in sediments while J was positively correlated with MDphi. Across the study period, the patterns of macrobenthic community were significantly different among all samplings and that the spatial difference of benthic community was best correlated with MDphi, TOC, TKN and water depth. A weak sign of recovery in macrobenthic community structure was detected at inside-harbour locations, with replacement of opportunistic by ubiquitous species over the two-year study. The slow recovery of macrobenthic community was related to sediment characteristics. Results of a larval settlement bioassay using the polychaete Capitella sp. I also demonstrated that the inside-harbour sediments were still unfavourable for colonization and larval settlement of species sensitive to pollution. The slow biodegradation of the organic pollutants and continuous presence of heavy metals in the sediment may hinder settlement and colonization of benthic animals. However, increases of H' and J were observed in a longer time scale when comparing the present data with those obtained four years ago. This suggested that a detectable recovery of benthic community in the harbour may take at least three years and a complete recovery may even take longer duration.

Influences of ammonia-nitrogen and dissolved oxygen on lysosomal integrity in green-lipped mussel Perna viridis: laboratory evaluation and field validation in Victoria Harbour, Hong Kong.

Lysosomal integrity in mussels has been applied as a biomarker to detect the pollution of trace organics and metals in the natural environments. However, few studies have examined the effects of water quality on the response of lysosomal integrity, in particular total ammonia-nitrogen (TAN) and dissolved oxygen (DO). This study demonstrated that high level of TAN (2.0mg/l) and low DO (2.5mg O(2)/l) could significantly reduce the lysosomal integrity in green-lipped mussel Perna viridis, respectively by 33% and 38%, whereas the mussel lysosomal integrity decreased by 70% in the combined treatment of TAN and low DO under laboratory conditions after one week. The mussel lysosomal integrity of all treatment groups could return to the control level after a three week recovery period. In the field validation in Victoria Harbour, Hong Kong during an one-year study period, lysosomal integrity in P. viridis identified the cleanest site east to the harbour, where the lowest TAN and highest DO concentrations were found. While lysosomal integrity in mussels seemed not affected by seasonal changes, approximately 40% of the variation of this biomarker could be attributable to the changes in TAN and DO in seawater. In conclusion, the response of the mussel lysosomal integrity can be confounded by both TAN and DO prevailing in the natural environments and thus caution must be exercised in relating the observed changes in lysosomal integrity to any specific pollutant in coastal water quality monitoring studies.

MiR-101 promotes nasopharyngeal carcinoma cell apoptosis through inhibiting Ras/Raf/MEK/ERK signaling pathway.

OBJECTIVE: Extra-cellular signal regulated kinase (ERK)/mitogen activated protein kinase (MAPK) signaling pathway is widely involved in cell proliferation and apoptosis. MAPK kinase 1 (MEK1) is the upstream protein kinase of ERK that can activate ERK/MAPK signaling pathway. microRNA-101 (MiR-101) down-regulation is found to be associated with nasopharyngeal carcinoma (NPC) pathogenesis. Bioinformatics analysis shows the complementary targeted relationship between miR-101 and the 3'-UTR of MEK1 mRNA. This study explores the role of miR-101 in regulating MEK1 expression, ERK/MAPK signaling pathway activation, and NPC pathogenesis. MATERIALS AND METHODS: Dual luciferase assay confirmed the targeted relationship between miR-101 and MEK1. MiR-101 and MEK1 expressions were compared in inflammatory nasopharynx tissue and NPC tissue. MiR-101, MEK1, phosphorylated ERK 1/2 (p-ERK1/2), survivin expressions in NP69, CNE-1, HONE1, and C666-2 cell lines were detected. NPC cell line C666-1 was cultured in vitro and divided into four groups, including miR-NC, miR-101, si-NC and si-MEK1. Cell apoptosis was determined by flow cytometry. Cell proliferation was evaluated by EdU staining. RESULTS: MiR-101 targeted inhibited MEK1 expression. MiR-101 was significantly down-regulated, while MEK1 was significantly elevated in NPC tissue compared with inflammatory nasopharynx tissue. MiR-101 was markedly declined, whereas MEK1, p-ERK1/2, and survivin were apparently increased in CNE-1, HONE1, and C666-1 cells compared with NP69 cells. MiR-101 mimic and/or si-MEK1 transfection significantly reduced MEK1, p-ERK1/2, and survivin levels, attenuated cell proliferation, and enhanced cell apoptosis. CONCLUSIONS: Down-regulation of miR-101 was related to NPC pathogenesis. MiR-101 elevation suppressed NPC cell proliferation and promoted apoptosis through targeted inhibiting MEK1 expression to alleviate ERK/MAPK signaling pathway and survivin expression.

Mechanism for differential sensitivity of the chromosome and growth cycles of mammalian cells to the rate of protein synthesis.

It has been documented widely that when the generation times of eucaryotic cells are lengthened by slowing the rate of protein synthesis, the duration of the chromosome cycle (S, G2, and M phases) remains relatively invariant. Paradoxically, when the growth of exponentially growing cultures of CHO cells is partially inhibited with inhibitors of protein synthesis, the immediate effect is a proportionate reduction in the rate of total protein, histone protein, and DNA synthesis. However, on further investigation it was found that over the next 2 h the rates of histone protein and DNA synthesis recover, in some cases completely to the uninhibited rate, while the synthesis rates of other proteins do not recover. We called this process chromosome cycle compensation. The amount of compensation seen in CHO cell cultures can account quantitatively for the relative invariance in the length of the chromosome cycle (S, G2, and M phases) reported for these cells. The mechanism for this compensation involves a specific increase in the levels of histone mRNAs. An invariant chromosome cycle coupled with a lengthening growth cycle must result in a disproportionate lengthening of the G1 phase. Thus, these results suggest that chromosome cycle invariance may be due more to specific cellular compensation mechanisms rather than to the more usual interpretation involving a rate-limiting step for cell cycle progression in the G1 phase.

Interrelationships of protein and DNA syntheses during replication of mammalian cells.

During the replication of chromatin, the syntheses of the histone protein and DNA components are closely coordinated but not totally linked. The interrelationships of total protein synthesis, histone protein synthesis, DNA synthesis, and mRNA levels have been investigated in Chinese hamster ovary cells subjected to several different types of inhibitors in several different temporal combinations. The results from these studies and results reported elsewhere can be brought together into a consistent framework which combines the idea of autoregulation of histone biosynthesis as originally proposed by W. B. Butler and G. C. Mueller (Biochim. Biophys. Acta 294:481-496, 1973] with the presence of basal histone synthesis and the effects of protein synthesis on DNA synthesis. The proposed framework obviates the difficulties of Butler and Mueller's model and may have wider application in understanding the control of cell growth.

A field experimental study on recolonization and succession of subtidal macrobenthic community in sediment contaminated with industrial wastes.

A field experiment was carried out in Hong Kong to study the patterns of recolonization and succession of subtidal macrobenthos in defaunated sediment contaminated with industrial wastes and to determine the time required for benthic recovery in the industrial-contaminated sediment. A total of 50 species was found with an average of 172 animals/tray and 24 species/tray recorded one month after deployment. Initial colonizers were predominantly polychaetes (96 animals/tray, accounting for 55.7%) and gastropods (47 animals/tray, accounting for 27.2%). Abundance of macrobenthos increased quickly to a peak (505 animals/tray) after four months, declined afterwards, and increased again till the end of the experiment. Species number peaked (57 species/tray) in the same month as abundance did, and gradually declined thereafter. Abundance, species number and diversity were significantly lower in the industrial-contaminated sediment as compared to the controls during the early successional stages, indicating the harmful effects of industrial wastes on recolonization and succession of macrobenthos. Although no significant differences in community parameters between the industrial-contaminated and the control sediments were found after eleven months, significant difference in species composition still existed after fourteen months, showing a relatively long-term impact of industrial wastes on macrobenthic community structure.

Measurement of O6-alkylguanine-DNA alkyltransferase activity in human cells and tumor tissues by restriction endonuclease inhibition.

A sensitive assay for O6-alkylguanine-DNA alkyltransferase activity in cell or tumor extracts has been devised. The theoretical basis of the new assay lies in the observation that certain restriction enzymes will not cleave DNA containing methylated bases. Thus, if a synthetic oligodeoxynucleotide with a restriction sequence containing O6-methylguanine were incubated with the restriction enzyme, this synthetic oligodeoxynucleotide should remain intact. However, if the guanine-O6 methyl group were first removed by O6-alkylguanine-DNA alkyltransferase present in certain cell or tissue extracts the synthetic oligodeoxynucleotide would be cleaved by the restriction enzyme. The parental oligodeoxynucleotide and its restriction products are separated from each other and analyzed on denaturing polyacrylamide gels. The extent of cleavage by the restriction enzyme is a direct assay of the content of O6-alkylguanine-DNA alkyltransferase in the cell/tumor extracts. The assay has been tested against cell culture and xenograft tumor systems and has performed in a predictive manner, correctly predicting five Mer- and three Mer+ phenotypes. Furthermore, the assay is quantitative and the number of molecules of the O6-alkylguanine-DNA alkyltransferase per cell estimated using this assay agrees with those that have been published.

Fate of newly synthesized histones in G1 and G0 cells.

We have shown that quiescent cells as well as those in the G1 phase of the cell cycle synthesize histones at a reduced but significant rate. Now, we show that the histones synthesized during G0 and G1 are stably incorporated into nuclei soon after synthesis. Micrococcal nuclease digestion of nuclei isolated from cells in G0 and G1 revealed that the specific histone variants synthesized in these different physiological states are found associated with DNA as nucleosomes. Nucleosomes were separated by polyacrylamide gel electrophoresis in a reducing buffer so that histone spot morphology, particularly that of the H3s was improved.