IPT9, a cis-zeatin cytokinin biosynthesis gene, promotes root growth

Cytokinin and auxin are plant hormones that coordinate many aspects of plant development. Their interactions in plant underground growth are well established, occurring at the levels of metabolism, signaling, and transport. Unlike many plant hormone classes, cytokinins are represented by more than one active molecule. Multiple mutant lines, blocking specific parts of cytokinin biosynthetic pathways, have enabled research in plants with deficiencies in specific cytokinin-types. While most of these mutants have confirmed the impeding effect of cytokinin on root growth, the ipt29 double mutant instead surprisingly exhibits reduced primary root length compared to the wild type. This mutant is impaired in cis-zeatin (cZ) production, a cytokinin-type that had been considered inactive in the past. Here we have further investigated the intriguing ipt29 root phenotype, opposite to known cytokinin functions, and the (bio)activity of cZ. Our data suggest that despite the ipt29 short-root phenotype, cZ application has a negative impact on primary root growth and can activate a cytokinin response in the stele. Grafting experiments revealed that the root phenotype of ipt29 depends mainly on local signaling which does not relate directly to cytokinin levels. Notably, ipt29 displayed increased auxin levels in the root tissue. Moreover, analyses of the differential contributions of ipt2 and ipt9 to the ipt29 short-root phenotype demonstrated that, despite its deficiency on cZ levels, ipt2 does not show any root phenotype or auxin homeostasis variation, while ipt9 mutants were indistinguishable from ipt29. We conclude that IPT9 functions may go beyond cZ biosynthesis, directly or indirectly, implicating effects on auxin homeostasis and therefore influencing plant growth

Computational Modeling and Analysis of Insulin Induced Eukaryotic Translation Initiation

Insulin, the primary hormone regulating the level of glucose in the bloodstream, modulates a variety of cellular and enzymatic processes in normal and diseased cells. Insulin signals are processed by a complex network of biochemical interactions which ultimately induce gene expression programs or other processes such as translation initiation. Surprisingly, despite the wealth of literature on insulin signaling, the relative importance of the components linking insulin with translation initiation remains unclear. We addressed this question by developing and interrogating a family of mathematical models of insulin induced translation initiation. The insulin network was modeled using mass-action kinetics within an ordinary differential equation (ODE) framework. A family of model parameters was estimated, starting from an initial best fit parameter set, using 24 experimental data sets taken from literature. The residual between model simulations and each of the experimental constraints were simultaneously minimized using multiobjective optimization. Interrogation of the model population, using sensitivity and robustness analysis, identified an insulin-dependent switch that controlled translation initiation. Our analysis suggested that without insulin, a balance between the pro-initiation activity of the GTP-binding protein Rheb and anti-initiation activity of PTEN controlled basal initiation. On the other hand, in the presence of insulin a combination of PI3K and Rheb activity controlled inducible initiation, where PI3K was only critical in the presence of insulin. Other well known regulatory mechanisms governing insulin action, for example IRS-1 negative feedback, modulated the relative importance of PI3K and Rheb but did not fundamentally change the signal flow

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

Family firms and internationalization:an exploratory study on high-tech entrepreneurial ventures

This paper empirically explores a highly relevant, although poorly investigated topic: internationalization of family firms that operate in high-tech industries. Specifically, we compare internationalization of family and nonfamily entrepreneurial ventures in these industries. Relying on prior studies on internationalization of family firms, we speculate on how the specificities of high-tech industries shape the advantages and disadvantages of family entrepreneurial ventures in pursuing internationalization as compared with their nonfamily peers. In the empirical part of the paper, through a rigorous quantitative analysis of unique data from 264 Italian high-tech entrepreneurial ventures, we explore whether in high-tech industries family entrepreneurial ventures are more (or less) likely to pursue internationalization than their nonfamily counterparts. Surprisingly enough, our econometric estimates indicate that, in high-tech industries, family entrepreneurial ventures exhibit a higher internationalization propensity than their nonfamily peer

Does corporate social performance yiedl any tangible financial benefit during a crisis? An event study on Lehman Brothers' Bankruptcy

The aim of this article is to empirically test – through the event study methodology – whether Corporate Social Performance (CSP) had any impact on Corporate Financial Performance (CFP) in the context of the crisis due to Lehman Brothers ’ bankruptcy. Drawing on previous studies belonging to different streams of literature, this article proposes three mechanisms that may have linked CSP to CFP in the context of the crisis. Stock prices of the non-fi nancial companies included in the S & P 500 stock market index are examined before and during the bankruptcy announcement. Empirical fi ndings show that in the context of the crisis due to Lehman Brothers ’ bankruptcy, CSP was positively correlated with short-term CFP (Abnormal Returns), thus providing a buffer effect

Corporate social responsibility reporting:a content analysis in family and non-family firms

Family firms are ubiquitous and play a crucial role across all world economies, but how they differ in the disclosure of social and environmental actions from non-family firms has been largely overlooked in the literature. Advancing the discourse on corporate social responsibility reporting, we examine how family influence on a business organization affects CSR reporting. The arguments developed here draw on institutional theory, using a rich body of empirical evidence gathered through a content analysis of the CSR reports of 98 large and medium-sized Italian firms. The grounded theory analysis informs and contextualizes several differences in the type and content of corporate social responsibility reports of family and non-family firms. Our findings show that in comparison to non-family firms, family firms disseminate a greater variety of CSR reports, are less compliant with CSR standards and place emphasis on different CSR topics. We thus contribute to family business and corporate social responsibility reporting literatures in several ways, offering implications for practice and outlining promising avenues for future research

M&A and diversification strategies: what effect on quality of inventive activity?

The aim of this paper is to examine how an acquirer's diversification strategy shapes the multiple dimensions of inventive activity. Differing from prior research, we use a set of indicators to investigate this phenomenon. In particular, we consider three different but complementary dimensions of inventive quality: technological impact, originality of the synthesized knowledge streams, and generality of applicability across different technological domains. The results obtained using a quasi-experimental approach show that diversification via acquisitions has a negative effect on post-acquisition technological impact. However, firms that have diversified outperform those firms that have not. Last, the acquirer's originality and generality increase after the merger and acquisition transaction, evidencing that the inventive activity benefited from the diversification strategy