Functional characterisation of sulfurtransferase proteins in higher plants

[no abstract

Conformational studies on Arabidopsis sulfurtransferase AtStr1 with spectroscopic methods

Sulfurtransferases/rhodaneses (Str) are enzymes widely distributed in archaea, prokaryota and eukaryota, and catalyze the transfer of sulfur from a donor molecule to a thiophilic acceptor substrate. In this reaction, Str cycles between the sulfur-free and the sulfur-substituted form. Two-domain Str consist of two globular domains of nearly identical size and conformation connected by a short linker sequence, which is elongated in plant two-domain Str proteins compared to Str in other organisms. The two-domain Arabidopsis thaliana Str1 protein (At1g 79230) was expressed in Escherichia coli as a mature protein, as a variant without the elongated linker sequence, and as AtStr1C332S and AtStr1C339V. The persulfuration state of the purified recombinant proteins was investigated in the presence and absence of sulfur donors by fluorescence spectroscopy. The secondary structure was analyzed by circular dichroism (CD) in the far-UV range, while overall changes in tertiary structure were determined by CD in the near-UV range. Finally, protein stability was analyzed by tryptic digestion. The elongated linker sequence is essential for correct conformation and stability, and thereby affects the catalytic activity of AtStr1. Replacement of the catalytic cysteine residue C332 leads to higher rigidity of the molecule, whereas replacement of C339 does not lead to any conformational changes, providing evidence of the direct involvement of C339 in catalysis.DFG/PA/764/1-

Malaria amongst febrile children: call for a pediatric malaria assessment tool

In 2017, malaria accounted for 435 000 deaths worldwide. Eleven percent (11%) of these deaths occurred in the Democratic Republic of Congo (DRC), where malaria continues to be a leading cause of morbidity and mortality. Children are amongst the most vulnerable to malaria, which causes 40% of childhood deaths in the country. Although many risk factors for developing malaria have been identified, there is a paucity of data available on the sociodemographic risk factors for pediatric malaria. A cross-sectional study including 131 febrile children aged 2 months to 14 years presenting to Heal Africa Hospital due to febrile illness. Guardians of participants answered a questionnaire about household and maternal characteristics, as well as child symptomatology. Malaria status was confirmed via blood smear. Results were analyzed using the chi-square test, likelihood ratios and a logistic regression. The absence of father as head of household (p=0.011) and gestational malaria (p=0.044) were significantly associated with pediatric malaria. This study provides insight into sociodemographic risk factors associated with pediatric malaria in the DRC. While further investigation is required, this study highlights the benefit of considering these factors when approaching the febrile child. A pediatric malaria assessment tool incorporating socio-demographics, symptoms and physical exam findings may guide investigations to reduce unnecessary testing and provide better patient-centred care

Limits on axion and light Higgs boson production in Y(1S) decays

We have searched for axion and light Higgs boson production in the channel Y(1S) → (a0 or h0)+gamma, where the non-interacting axion a0 and the Higgs boson h0 do not decay in the detector. We find no evidence for an axion and give an upper limit, Br(Y(1S) -> a0 gamma) <4.0x10(-5) (90% CL), for long-lived axions. Combining our limit with the previous search in J/Psi decays, we are able to rule out the axion in the standard model with first order QCD corrections. Our Y(1S) data also rule out a Higgs boson with mass m<86 MeV

Developmental co-occurrence of psychopathology dimensions in childhood

Background: Comorbidity between psychopathologies may be attributed to genetic and environmental differences between people as well as causal processes within individuals, where one pathology increases risk for another. Disentangling between-person (co)variance from within-person processes of psychopathology dimensions across childhood may shed light on developmental causes of comorbid mental health problems. Here, we aim to determine whether and to what extent directional relationships between psychopathology dimensions within-person, and between individuals within families, play a role in comorbidity.// Methods: We conducted random intercepts cross-lagged panel model (RI-CLPM) analyses to unravel the longitudinal co-occurrence of child psychopathology dimensions, jointly estimating between-person and within-person processes from childhood to early adolescence (age 7–12). We further developed an extension of the model to estimate sibling effects within-family (wf-RI-CLPM). Analyses were separately conducted in two large population-based cohorts, TEDS and NTR, including parent-rated measures of child problem behaviours based on the SDQ and CBCL scales respectively.// Results: We found evidence for strong between-person effects underlying the positive intercorrelation between problem behaviours across time. Beyond these time-varying within-person processes accounted for an increasing amount of trait variance, within- and cross-trait, overtime in both cohorts. Lastly, by accommodating family level data, we found evidence for reciprocal directional influences within sib-pairs longitudinally.// Conclusions: Our results indicate that within-person processes partly explain the co-occurrence of psychopathology dimensions across childhood, and within sib-pairs. Analyses provided substantive results on developmental processes underlying comorbidity in behavioural problems. Future studies should consider different developmental timeframes to shed more light on the processes contributing to developmental comorbidity./

a multicentre prevalence study

Objectives: The aim of this study was to measure the prevalence of skin diseases in aged nursing home residents and to explore possible associations with demographic and medical characteristics. Design: Descriptive multicentre prevalence study. Setting and participants: The study was conducted in a random sample of ten institutional long-term care facilities in the federal state of Berlin, Germany. In total, n=223 residents were included. Results: In total, 60 dermatological diseases were diagnosed. The most frequently diagnosed skin disease was xerosis cutis (99.1%, 95% CI 97.7% to 100.0%) followed by tinea ungium (62.3%, 95% CI 56.0% to 69.1%) and seborrheic keratosis (56.5%, 95% CI 50.2% to 63.0%). Only few bivariate associations have been detected between skin diseases and demographic and medical characteristics. Conclusion: Study results indicate that almost every resident living in residential care has at least one dermatological diagnosis. Dermatological findings range from highly prevalent xerosis and cutaneous infection up to skin cancer. Not all conditions require immediate dermatological treatment and can be managed by targeted skin care interventions. Caregivers need knowledge and diagnostic skills to make appropriate clinical decisions. It is unlikely that specialised dermatological care will be delivered widely in the growing long-term care sector. Trial registration number: This study is registered at https://clinicaltrials.gov/ct2/show/NCT02216526

Resultados de la labor de Investigación 2016-2021

Este informe tiene como objetivo presentar los principales aportes de la labor de investigación realizada en la Universidad de Costa Rica en el período 2016-2021, correspondiendo a los primeros proyectos que pueden vincularse con la entrada en vigencia de la Agenda del Desarrollo Sostenible 2030. Los datos de proyectos y convenios en en este informe provienen del Sistema de Información de Proyectos (SIP), agosto 2022.UCR::Vicerrectoría de Investigació