312 research outputs found

    Hydrolysis of 5-methylfuran-2-yl to 2,5-dioxopentanyl allows for stable bio-orthogonal proximity-induced ligation

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    Ligation methodologies featuring bio-orthogonal units and leading to the formation of a stable adduct are the ideal candidates for being applied in a biological context. However, most of the available strategies rely on highly reactive species that require careful handling, or on the activation of pro-reactive functional groups. We here report on a proximity-induced ligation reaction that relies on a stable 2,5-dione, that can be conveniently generated under acidic conditions from a 2,5-dialkylfuran building block, and hydrazine nucleophiles. This bio-orthogonal ligation, which proceeds under physiological conditions, does not require any stimulus or trigger and leads to the formation of a pyridazinium adduct that demonstrates excellent stability under harsh conditions (24 h at 90 °C). The reaction was applied to the formation of PNA-PNA adducts, DNA- and RNA-templated ligations, and for the formation of peptide-peptide adducts in solution. This convenient methodology was further implemented on plastic and glass surfaces to realize self-addressable covalent constructs

    Beyond small molecules: Targeting G-quadruplex structures with oligonucleotides and their analogues

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    G-Quadruplexes (G4s) are widely studied secondary DNA/RNA structures, naturally occurring when G-rich sequences are present. The strategic localization of G4s in genome areas of crucial importance, such as proto-oncogenes and telomeres, entails fundamental implications in terms of gene expression regulation and other important biological processes. Although thousands of small molecules capable to induce G4 stabilization have been reported over the past 20 years, approaches based on the hybridization of a synthetic probe, allowing sequence-specific G4-recognition and targeting are still rather limited. In this review, after introducing important general notions about G4s, we aim to list, explain and critically analyse in more detail the principal approaches available to target G4s by using oligonucleotides and synthetic analogues such as Locked Nucleic Acids (LNAs) and Peptide Nucleic Acids (PNAs), reporting on the most relevant examples described in literature to date

    X-linked heterochromatin distribution in the holocentric chromosomes of the green apple aphid Aphis pomi

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    Chromatin organization in the holocentric chromosomes of the green apple aphid Aphis pomi has been investigated at a cytological level after C-banding, NOR, Giemsa, fluorochrome staining and fluorescent in situ hybridization (FISH). C-banding technique showed that heterochromatic bands are exclusively located on X chromosomes. This data represents a peculiar feature that clearly contradicts the equilocal distribution of heterochromatin typical of monocentric chromosomes. Moreover, silver staining and FISH carried out with a 28S rDNA probe localized rDNA genes on one telomere of each X chromosome; CMA(3) staining reveals that these silver positive telomeres are, the only GC-rich regions among A. pomi heterochromatin, whereas all other C-positive bands are DAPI positive thus containing AT-rich DNA

    Sperm nuclear DNA damage and altered chromatin structure: effect on fertilization and embryo development

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    In the first part of this report we investigate whether chromatin anomalies in human spermatozoa can influence fertilization after intracytoplasmic sperm injection (ICSI). We have examined the sperm chromatin packaging quality using the chromomycin A3 (CMA3) fluorochrome and the presence of DNA damage in spermatozoa using in-situ nick translation. When comparing the spermatozoa of patients undergoing in-vitro fertilization (IVF) and ICSI distinct differences are evident in that ICSI males have a higher CMA3 fluorescence, indicating spermatozoa with loosely packed chromatin, and more spermatozoa containing endogenous DNA nicks. When examining the unfertilized oocytes of ICSI patients we found that men who had a high percentage of anomalies in their chromatin, i.e. >30% CMA3 fluorescence and >10% nicks, had more than double the number of unfertilized oocytes containing spermatozoa that had remained condensed. The observation that failed fertilized oocytes, injected with spermatozoa from patients with a higher percentage of sperm nuclear anomalies, contain more condensed spermatozoa indicates that a selection process against these spermatozoa may be in place at the time of fertilization. In the second part of the study we show that spare ICSI embryos have significantly lower rates of development to the blastocyst stage compared with those developed after routine IVF. These results show that a greater understanding of the molecular basis of male infertility is therefore needed to broaden our knowledge on the effect that abnormal spermatozoa have on fertilization and embryo developmen

    Sperm chromatin anomalies can influence decondensation after intracytoplasmic sperm injection

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    In this study we investigated whether morphology and chromatin anomalies in human spermatozoa can influence fertilization after intracytoplasmic sperm injection (ICSI). We examined unfertilized oocytes, using the fluorochrome Hoechst 33342, to determine whether a relationship exists between failure of fertilization and sperm chromatin quality. Sperm chromatin packaging quality was assessed using the chromomydn A3 (CMA3) fluorochrome, and the presence of DNA damage in spermatozoa, using in-situ nick translation. Normal males present sperm parameters with a normal morphology of >20%, CMA3 fluorescence of <30% and exhibit endogenous nicks in <10% of their spermatozoa. When patients were separated according to these values no difference was observed in their fertilization rates after ICSL When the unfertilized ICSI oocytes were examined, we found that patients with CMA3 fluorescence of <30% and nicks in <10% of their spermatozoa had only 17.5 and 21.6% respectively of their unfertilized oocytes containing spermatozoa that remained condensed. In contrast, patients with higher CMA3 and nick values had a significantly higher number, 412 and 48.9%, of their unfertilized oocytes containing condensed spermatozoa. Sperm morphology did not show any such pattern. The percentage of spermatozoa which had initiated decondensation in unfertilized oocytes was not influenced by morphology, CMA3 fluorescence or nicks. In light of these results we postulate that poor chromatin packaging and/or damaged DNA may contribute to failure of sperm decondensation after ICSI and result in failure of fertilizatio

    Case studies of automation in services

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    A full understanding of the technological complexity underlying robotics and automation is still lacking, most of all when focusing on the impacts on work in services. By means of a qualitative analysis based on over 50 interviews to HR managers, IT technicians, workers and trade union delegates, this work provides evidence on the main changes occurring at shopfloor level in selected Italian companies having adopted technological artefacts potentially affecting labour tasks by automating processes. The analysis of interviews complemented with visits to the companies and desk research on business documents highlights that so far labour displacement due to the adoption of automation technologies is not yet in place, while tasks and organizational reconfiguration appear more widespread. Major heterogeneity applies across plants due to the final product/service produced, the techno-organizational capabilities of the firm and the type of strategic orientation versus technological adoption. These elements also affect drivers and barriers to technological adoption. Overall, the analysis confirms the complexity in automating presumably low-value-added phases: human labour remains crucial in conducting activities that require flexibility, adaptability and reconfiguration of physical tasks. Further, human agency and worker representation, in particular the role of trade unions, are almost disregarded and not considered by the firms when deciding to introduce a new technology

    A performance score of the quality of inpatient diabetes care is a marker of clinical outcomes and suggests a cause-effect relationship between hypoglycaemia and the risk of in-hospital mortality

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    Aims: To build a tool to assess the management of inpatients with diabetes mellitus and to investigate its relationship, if any, with clinical outcomes. Materials and methods: A total of 678 patients from different settings, Internal Medicine (IMU, n = 255), General Surgery (GSU, n = 230) and Intensive Care (ICU, n = 193) Units, were enrolled. A work-flow of clinical care of diabetes was created according to guidelines. The workflow was divided into five different domains: (a) initial assessment; (b) glucose monitoring; (c) medical therapy; (d) consultancies; (e) discharge. Each domain was assessed by a performance score (PS), computed as the sum of the scores achieved in a set of indicators of clinical appropriateness, management and patient empowerment. Appropriate glucose goals were included as intermediate phenotypes. Clinical outcomes included: hypoglycaemia, survival rate and clinical conditions at discharge. Results: The total PS and those of initial assessment and glucose monitoring were significantly lower in GSU with respect to IMU and ICU (P &lt;.0001). The glucose monitoring PS was associated with lower risk of hypoglycaemia (OR = 0.55; P &lt;.0001), whereas both the PSs of glucose monitoring and medical therapy resulted associated with higher in-hospital survival only in the IMU ward (OR = 6.67 P =.001 and OR = 2.38 P =.03, respectively). Instrumental variable analysis with the aid of PS of glucose monitoring showed that hypoglycaemia may play a causal role in in-hospital mortality (P =.04). Conclusions: The quality of in-hospital care of diabetes may affect patient outcomes, including glucose control and the risk of hypoglycaemia, and through the latter it may influence the risk of in-hospital mortality

    Gene Modulation by Peptide Nucleic Acids (PNAs) Targeting microRNAs (miRs)

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    Since non-viral gene therapy was developed and employed in different in vitro and in vivo experimental systems as an effective way to control and modify gene expression, RNA has been considered as a molecular target of great relevance (Li &Huang, 2008, López-Fraga et al., 2008). In combination with standard chemotherapy, the siRNA therapy can reduce the chemoresistance of certain cancers, demonstrating its potential for treating many malignant diseases. Examples of RNA sequences to be targeted for therapeutic applications are mRNAs coding oncoproteins or RNA coding anti-apoptotic proteins for the development of anti-cancer therapy. In the last years, progresses in molecular biology have allowed to identify many genes Coding for small non coding RNA molecules, microRNA (miRNAs or miRs), able to regulate gene expression at the translation level (Huang et al., 2008, Shrivastava & Shrivastava, 2008, Sahu et al. 2007, Orlacchio et al., 2007, Williams et al., 2008, Papagiannakopoulos & Kosik, 2008). Accordingly, an increasing number of reports associate the changed expression with specific phenotypes and even with pathological conditions (Garzon & Croce, 2008, Mascellani et al., 2008, Sontheimer & Carthew, 2005, Filipowicz et al., 2005, Alvarez-Garcia & Miska, 2005). Interestingly, microRNAs play a double role in cancer, behaving both as oncogenes or tumor suppressor genes. In general, miRs promoting cancer targets mRNA coding for tumor-suppression proteins, while microRNAs exhibiting tumor-suppression properties usually target mRNAs coding oncoproteins. MicroRNAs which have been demonstrated to play a crucial role in the initiation and progression of human cancer are defined as oncogenic miRNAs (oncomiRs) (Cho, 2007). The oncomiR expression profiling of human malignancies has also identified a number of diagnostic and prognostic cancer signals (Cho, 2007, Lowery et al., 2008). Moreover, microRNAs have been firmly demonstrated to be involved in cancer metastasis (metastamiRs). Examples of metastasis-promoting microRNAs are, miR-10b (Calin et al., 2006), miR-373 and - 520c (Woods et al., 2007), miR-21, -143 and -182 (Hayashita et al., 2005; Si et al., 2007; Zhu et al.,2007). Reviews on metastamiR has been recently published Hurst et al. (Hurst et al. 2009, Edmonds et al. 2009). Reviews on metastamiRs has been recently published by Hurst et al
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