Harnessing dual-mode RIPK1 ligands for cross-species anti-necroptosis inhibitor compounds.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) has a crucial role in cell death and inflammation. A promising approach to develop novel inhibitors of RIPK1 mediated necroptosis is to mix the different binding modes of the known RIPK1 inhibitors into one molecule. Herein we report the synthesis and biological evaluation of novel mixed type inhibitors. Using Eclitasertib as a starting point, and applying our previous, published knowledge regarding cyclic malonamides, we successfully identified a library of active compounds. The active enantiomer of the most balanced and promising compound was subjected to pharmacokinetics and in vivo hypothermia study in mice.

Design, synthesis and biological evaluation of novel cyclic malonamide derivatives as selective RIPK1 inhibitors.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) plays a key role in cell death and inflammation. RIPK1 is a well-established therapeutic target, due to the presence of a unique kinase-regulating allosteric pocket, which enables selective inhibition. Herein we used GSK2982772 as our starting point in our discovery campaign. Applying isosteric replacement, we successfully identified the malonamide scaffold, instead of the well-established serine template. Further structural optimization led to the design and synthesis of a series of analog inhibitors. The enantiomers of the most promising compound were tested on 97 different kinases. The active enantiomer proved to be kinase selective.

dNTPpoolDB: a manually curated database of experimentally determined dNTP pools and pool changes in biological samples.

Stimulated by the growing interest in the role of dNTP pools in physiological and malignant processes, we established dNTPpoolDB, the database that offers access to quantitative data on dNTP pools from a wide range of species, experimental and developmental conditions (https://dntppool.org/). The database includes measured absolute or relative cellular levels of the four canonical building blocks of DNA and of exotic dNTPs, as well. In addition to the measured quantity, dNTPpoolDB contains ample information on sample source, dNTP quantitation methods and experimental conditions including any treatments and genetic manipulations. Functions such as the advanced search offering multiple choices from custom-built controlled vocabularies in 15 categories in parallel, the pairwise comparison of any chosen pools, and control-treatment correlations provide users with the possibility to quickly recognize and graphically analyse changes in the dNTP pools in function of a chosen parameter. Unbalanced dNTP pools, as well as the balanced accumulation or depletion of all four dNTPs result in genomic instability. Accordingly, key roles of dNTP pool homeostasis have been demonstrated in cancer progression, development, ageing and viral infections among others. dNTPpoolDB is designated to promote research in these fields and fills a longstanding gap in genome metabolism research.

Emotion Regulation Predicts Depressive Symptoms in Adolescents: A Prospective Study.

Emotion regulation as a proximal factor has been linked with depressive symptoms. However, studies have mainly focused on a limited number of strategies and have mostly been cross-sectional in design. This is particularly evident when examining the protective effects of adaptive strategies. This study aimed to investigate the prospective relationship between putatively adaptive and maladaptive emotion regulation strategies and depressive symptoms among adolescents. Additionally, a person-oriented approach was applied to identify latent classes of adolescents based on their depressive symptoms and compared these classes in terms of their adaptive and maladaptive strategies. Two waves of data from a prospective study, which included 1371 youth (mean age: 15.66 years; SD = 0.49 years; 55.1% girls), were analysed. The two points of data collection were spaced approximately half a year apart. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale, and putatively adaptive and maladaptive emotion regulation strategies were assessed with the Cognitive Emotion Regulation Questionnaire. Seven strategies (acceptance, positive refocusing, positive reappraisal, putting into perspective, self-blame, rumination, and catastrophizing) were categorised into adaptive and maladaptive factors using exploratory structural equation modeling. After controlling for gender, age, and depressive symptoms at Time 1, both maladaptive and adaptive emotion regulation strategies at Time 1 predicted depressive symptoms at Time 2. Three subgroups emerged based on the intensity of depressive symptoms across the waves: the stable low, stable moderate, and stable high depressive symptom groups. The use of maladaptive emotion regulation strategies (such as rumination, self-blame, and catastrophizing) at Time 1 was more pronounced in the stable moderate and high symptom groups compared to the stable low depressive symptom group. The comparable prospective associations between putatively adaptive and maladaptive strategies with symptoms suggest the need to identify factors that may mitigate the negative impact of maladaptive emotion regulation and/or promote adaptive emotion regulation to buffer the effects of everyday stressors.

Tilorone increases glucose uptake in vivo and in skeletal muscle cells by enhancing Akt2/AS160 signaling and glucose transporter levels.

Skeletal muscle plays a major role in whole-body glucose metabolism. Insulin resistance in skeletal muscle is characterized by decreased insulin-stimulated glucose uptake resulting from impaired intracellular trafficking and decreased glucose transporter 4 (GLUT4) expression. In this study, we illustrated that tilorone, a low-molecular-weight antiviral agent, improves glucose uptake in vitro and in vivo. Tilorone increased bone morphogenetic protein (BMP) signaling in C2C12 myoblasts, the transcription of multiple BMPs (BMP2, BMP4, BMP7, and BMP14), Smad4 expression, and the phosphorylation of BMP-mediated Smad1/5/8. The activation of Akt2/AS160 (TBC1D4) signaling, the critical regulator of GLUT4 translocation, was also increased, as well as the levels of GLUT4 and GLUT1, leading to enhanced uptake of the radioactively labeled glucose analog 18 F-fluoro-2-deoxyglucose (18 FDG). However, this excess glucose content did not result in increased ATP formation by mitochondrial respiration; both basal and ATP-linked respiration were diminished, thereby contributing to the induction of AMPK. In differentiated myotubes, AS160 phosphorylation and 18 FDG uptake also increased. Moreover, tilorone administration further increased insulin-stimulated phosphorylation of Akt2 and glucose uptake of myotubes indicating an insulin-sensitizing effect. Importantly, during in vivo experiments, the systemic administration of tilorone resulted in increased 18 FDG uptake of skeletal muscle, liver, and adipose tissue in C57BL/6 mice. Our results provide new perspectives for the treatment of type 2 diabetes, which has a limited number of treatments that regulate protein expression or translocation.

The iNaturalist platform as a source of data to study amphibians in Brazil.

Based on debilitating recent budget cuts for science, Brazilian researchers had to find alternative ways to continue scientific production. Here we provide a perspective for the use of citizen-science data deposited in the iNaturalist platform as an alternative source of data to support biodiversity research. Observations contributed by volunteers can be analyzed at large spatial and temporal scales and can respond to questions in behavioral and population ecology. We analyzed this potential through the example of Brazilian amphibians, a group that is less studied worldwide than birds. In fact, to our knowledge, only two studies have been published that are based on citizen-science data for Brazilian amphibians. At the time of writing, the iNaturalist platform has over 14,800 research grade observations from Brazil, representing 698 species, a number increasing daily. Compared to other species-rich countries, volunteer-collected datasets from Brazil cover a relatively high taxonomic diversity (61%), providing a plethora of valuable data. Despite this potential, there are large spatial gaps in sampling in Brazil. Here we encourage established and budding herpetologists not only to use the platform to retrieve data, but also to contribute to iNaturalist actively, with new observations, as well as by identifying species in existing records.

Posts Supporting Anti-Environmental Policy in Brazil are Shared More on Social Media.

Weakening environmental laws supported by disinformation are currently of concern in Brazil. An example of disinformation is the case of the "firefighter cattle". Supporters of this idea believe that by consuming organic mass, cattle decrease the risk of fire in natural ecosystems. This statement was cited by a member of the Bolsonaro government in response to the unprecedented 2020 fires in the Pantanal, as well as in support of a new law that enables extensive livestock in protected areas of this biome. By suggesting that grazing benefits the ecosystem, the "firefighter cattle" argument supports the interests of agribusiness. However, it ignores the real costs of livestock production on biodiversity. We analysed the social repercussion of the "firefighter cattle" by analysing public reactions to YouTube, Facebook, and Google News posts. These videos and articles and the responses to them either agreed or disagreed with the "firefighter cattle". Supportive posts were shared more on social media and triggered more interactions than critical posts. Even though many netizens disagreed with the idea of "firefighter cattle", it has gone viral, and was used as a tool to strengthen anti-environmental policies. We advocate that government institutions should use resources and guidelines provided by the scientific community to raise awareness. These materials include international reports produced by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) and the Intergovernmental Panel on Climate Change (IPCC). We need to curb pseudoscience and misinformation in political discourse, avoiding misconceptions that threaten natural resources and confuse global society.

A user-friendly, high-throughput tool for the precise fluorescent quantification of deoxyribonucleoside triphosphates from biological samples.

Cells maintain a fine-tuned, dynamic concentration balance in the pool of deoxyribonucleoside 5'-triphosphates (dNTPs). This balance is essential for physiological processes including cell cycle control or antiviral defense. Its perturbation results in increased mutation frequencies, replication arrest and may promote cancer development. An easily accessible and relatively high-throughput method would greatly accelerate the exploration of the diversified consequences of dNTP imbalances. The dNTP incorporation based, fluorescent TaqMan-like assay published by Wilson et al. has the aforementioned advantages over mass spectrometry, radioactive or chromatography based dNTP quantification methods. Nevertheless, the assay failed to produce reliable data in several biological samples. Therefore, we applied enzyme kinetics analysis on the fluorescent dNTP incorporation curves and found that the Taq polymerase exhibits a dNTP independent exonuclease activity that decouples signal generation from dNTP incorporation. Furthermore, we found that both polymerization and exonuclease activities are unpredictably inhibited by the sample matrix. To resolve these issues, we established a kinetics based data analysis method which identifies the signal generated by dNTP incorporation. We automated the analysis process in the nucleoTIDY software which enables even the inexperienced user to calculate the final and accurate dNTP amounts in a 96-well-plate setup within minutes.

In Vivo Preclinical Assessment of ß-Amyloid-Affine [11C]C-PIB Accumulation in Aluminium-Induced Alzheimer's Disease-Resembling Hypercholesterinaemic Rat Model.

Aluminum (Al) excess and hypercholesterinaemia are established risks of Alzheimer's disease (AD). The aim of this study was to establish an AD-resembling hypercholesterinaemic animal model-with the involvement of 8 week and 48 week-old Fischer-344 rats-by Al administration for the safe and rapid verification of ß-amyloid-targeted positron emission tomography (PET) radiopharmaceuticals. Measurement of lipid parameters and ß-amyloid-affine [11C]C-Pittsburgh Compound B ([11C]C-PIB) PET examinations were performed. Compared with the control, the significantly elevated cholesterol and LDL levels of the rats receiving the cholesterol-rich diet support the development of hypercholesterinaemia (p ≤ 0.01). In the older cohort, a notably increased age-related radiopharmaceutical accumulation was registered compared to in the young (p ≤ 0.05; p ≤ 0.01). A monotherapy-induced slight elevation of mean standardised uptake values (SUVmean) was statistically not significant; however, adult rats administered a combined diet expressed remarkable SUVmean increment compared to the adult control (SUVmean: from 0.78 ± 0.16 to 1.99 ± 0.28). One and two months after restoration to normal diet, the cerebral [11C]C-PIB accumulation of AD-mimicking animals decreased by half and a third, respectively, to the baseline value. The proposed in vivo Al-induced AD-resembling animal system seems to be adequate for the understanding of AD neuropathology and future drug testing and radiopharmaceutical development.

In Vivo Assessments of Mesoblastic Nephroma (Ne/De) and Myelomonoblastic Leukaemia (My1/De) Tumour Development in Hypercholesterolemia Rat Models.

Given the rising prevalence of lipid metabolic disorders and malignant diseases, we aimed to establish an in vivo hypercholesterinaemic tumour-bearing rat model for the induction and assessment of these conditions. A normal standard CRLT/N, 2 (baseline),- or 4 (2 + 2, pretreated)-week-long butter and cholesterol rich (BCR) diet was applied to mesoblastic nephroma (Ne/De) and myelomonoblastic leukaemia (My1/De) tumour-bearing and healthy control Long­Evans and Fischer 344 rats. The beginning of chow administration started in parallel with tumour induction and the 2 weeks of pre-transplantation in the baseline and pretreated groups, respectively. Fourteen days post-inoculation, the measurement of lipid parameters and [18F]F-FDG PET/MRI examinations was executed. The comparable lipid status of baseline healthy and tumorous rats proves that regardless of tumour presence, BCR-based hypercholesterolemia was achieved. A higher tumour mass among pretreated tumorous animals was found when compared to the control groups (p < 0.05, p < 0.01). Further, a visually greater [18F]F-FDG accumulation was observed in pretreated BCR tumorous animals; however, the quantitative data (SUVmean: 9.86 ± 0.98, 9.68 ± 1.24; SUVmax: 19.63 ± 1.20; 17.56 ± 3.21 for Ne/De and My1/De, respectively) were not statistically significantly different from those of the CRLT/N tumorous rats (SUVmean: 8.40 ± 1.42, 7.22 ± 1.06 and SUVmax: 15.99 ± 2.22, 12.46 ± 1.96 for control Ne/De and My1/De, respectively). Our model seems to be appropriate for simultaneously investigating hypercholesterolemia and cancer in the same rat.

PET Probes for Preclinical Imaging of GRPR-Positive Prostate Cancer: Comparative Preclinical Study of [68Ga]Ga-NODAGA-AMBA and [44Sc]Sc-NODAGA-AMBA.

Gastrin-releasing peptide receptors (GRPR) are overexpressed in prostate cancer (PCa). Since bombesin analogue aminobenzoic-acid (AMBA) binds to GRPR with high affinity, scandium-44 conjugated AMBA is a promising radiotracer in the PET diagnostics of GRPR positive tumors. Herein, the GRPR specificity of the newly synthetized [44Sc]Sc-NODAGA-AMBA was investigated in vitro and in vivo applying PCa PC-3 xenograft. After the in-vitro assessment of receptor binding, PC-3 tumor-bearing mice were injected with [44Sc]Sc/[68Ga]Ga-NODAGA-AMBA (in blocking studies with bombesin) and in-vivo PET examinations were performed to determine the radiotracer uptake in standardized uptake values (SUV). 44Sc/68Ga-labelled NODAGA-AMBA was produced with high molar activity (approx. 20 GBq/µmoL) and excellent radiochemical purity. The in-vitro accumulation of [44Sc]Sc-NODAGA-AMBA in PC-3 cells was approximately 25-fold higher than that of the control HaCaT cells. Relatively higher uptake was found in vitro, ex vivo, and in vivo in the same tumor with the 44Sc-labelled probe compared to [68Ga]Ga-NODAGA-AMBA. The GRPR specificity of [44Sc]Sc-NODAGA-AMBA was confirmed by significantly (p ≤ 0.01) decreased %ID and SUV values in PC-3 tumors after bombesin pretreatment. The outstanding binding properties of the novel [44Sc]Sc-NODAGA-AMBA to GRPR outlines its potential to be a valuable radiotracer in the imaging of GRPR-positive PCa.

The role of the microbiome in ovarian cancer: mechanistic insights into oncobiosis and to bacterial metabolite signaling.

Ovarian cancer is characterized by dysbiosis, referred to as oncobiosis in neoplastic diseases. In ovarian cancer, oncobiosis was identified in numerous compartments, including the tumor tissue itself, the upper and lower female genital tract, serum, peritoneum, and the intestines. Colonization was linked to Gram-negative bacteria with high inflammatory potential. Local inflammation probably participates in the initiation and continuation of carcinogenesis. Furthermore, local bacterial colonies in the peritoneum may facilitate metastasis formation in ovarian cancer. Vaginal infections (e.g. Neisseria gonorrhoeae or Chlamydia trachomatis) increase the risk of developing ovarian cancer. Bacterial metabolites, produced by the healthy eubiome or the oncobiome, may exert autocrine, paracrine, and hormone-like effects, as was evidenced in breast cancer or pancreas adenocarcinoma. We discuss the possible involvement of lipopolysaccharides, lysophosphatides and tryptophan metabolites, as well as, short-chain fatty acids, secondary bile acids and polyamines in the carcinogenesis of ovarian cancer. We discuss the applicability of nutrients, antibiotics, and probiotics to harness the microbiome and support ovarian cancer therapy. The oncobiome and the most likely bacterial metabolites play vital roles in mediating the effectiveness of chemotherapy. Finally, we discuss the potential of oncobiotic changes as biomarkers for the diagnosis of ovarian cancer and microbial metabolites as possible adjuvant agents in therapy.

Record-breaking wildfires in the world's largest continuous tropical wetland: Integrative fire management is urgently needed for both biodiversity and humans.

In the Brazilian Pantanal, wildfire occurrence has increased, reaching record highs of over 40,000 km2 in 2020. Smoke from wildfires worsened the situation of isolated, as well as urban communities, already under an increasing toll of COVID-19. Here we review the impacts and the possible causes of the 2020 mega-fires and recommend improvements for public policies and fire management in this wetland. We calculated the amount of area burnt annually since 2003 and describe patterns in precipitation and water level measurements of the Paraguay River. Our analyses revealed that the 2020 wildfires were historically unprecedented, as 43% of the area (over 17,200 km2) had not been burnt previously in the last two decades. The extent of area affected in 2020 represents a 376% increase compared to the annual average of the area burnt annually in the last two decades, double than the value in 2019. Potential factors responsible for this increase are (i) severe drought decreased water levels, (ii) the fire corridor was located in the Paraguay River flood zone, (iii) constraints on firefighters, (iv) insufficient fire prevention strategy and agency budget reductions, and (v) recent landscape changes. Climate and land use change will further increase the frequency of these extreme events. To make fire management more efficient and cost-effective, we recommend the implementation of an Integrated Fire Management program in the Pantanal. Stakeholders should use existing traditional, local ecological, and scientific knowledge to form a collective strategy with clear, achievable, measurable goals, considering the socio-ecological context. Permanent fire brigades, including indigenous members, should conduct year-round fire management. Communities should cooperate to create a collaborative network for wildfire prevention, the location and characteristics (including flammability) of infrastructures should be (re)planned in fire-prone environments considering and managing fire-catalysed transitions, and depending on the severity of wildfires. The 2020 wildfires were tackled in an ad-hoc fashion and prioritisation of areas for urgent financial investment, management, protection, and restoration is necessary to prevent this catastrophe from happening again.

Ceftazidime-avibactam and ceftolozane-tazobactam susceptibility of multidrug resistant Pseudomonas aeruginosa strains in Hungary.

Our objective was to compare the activity ceftazidime-avibactam (C/A) and ceftolozane-tazobactam (C/T) against multidrug (including carbapenem) resistant Pseudomonas aeruginosa clinical isolates collected from six diagnostic centers in Hungary and to reveal the genetic background of their carbapenem resistance. Two hundred and fifty consecutive, non-duplicate, carbapenem-resistant multidrug resistant (MDR) P. aeruginosa isolates were collected in 2017. Minimal inhibitory concentration values of ceftazidime, cefepime, piperacillin/tazobactam, C/A and C/T were determined by broth microdilution method and gradient diffusion test. Carbapenem inactivation method (CIM) test was performed on all isolates. Carbapenemase-encoding blaVIM, blaIMP, blaKPC, blaOXA-48-like and blaNDM genes were identified by multiplex PCR. Of the isolates tested, 33.6% and 32.4% showed resistance to C/A and C/T, respectively. According to the CIM test results, 26% of the isolates were classified as carbapenemase producers. The susceptibility of P. aeruginosa isolates to C/A and C/T without carbapenemase production was 89% and 91%, respectively. Of the CIM-positive isolates, 80% were positive for blaVIM and 11% for blaNDM. The prevalence of Verona integron-encoded metallo-beta-lactamase (VIM)-type carbapenemase was 20.8%. NDM was present in 2.8% of the isolates. Although the rate of carbapenemase-producing P. aeruginosa strains is high, a negative CIM result indicates that either C/A or C/T could be effective even if carbapenem resistance has been observed.

Formulation of Creams Containing Spirulina Platensis Powder with Different Nonionic Surfactants for the Treatment of Acne Vulgaris.

Natural products used in the treatment of acne vulgaris may be promising alternative therapies with fewer side effects and without antibiotic resistance. The objective of this study was to formulate creams containing Spirulina (Arthrospira) platensis to be used in acne therapy. Spirulina platensis belongs to the group of micro algae and contains valuable active ingredients. The aim was to select the appropriate nonionic surfactants for the formulations in order to enhance the diffusion of the active substance and to certify the antioxidant and antibacterial activity of Spirulina platensis-containing creams. Lyophilized Spirulina platensis powder (SPP) was dissolved in Transcutol HP (TC) and different types of nonionic surfactants (Polysorbate 60 (P60), Cremophor A6:A25 (CR) (1:1), Tefose 63 (TFS), or sucrose ester SP 70 (SP70)) were incorporated in creams as emulsifying agents. The drug release was evaluated by the Franz diffusion method and biocompatibility was tested on HaCaT cells. In vitro antioxidant assays were also performed, and superoxide dismutase (SOD) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were executed. Antimicrobial activities of the selected compositions were checked against Staphylococcus aureus (S. aureus) and Cutibacteriumacnes (C. acnes) (formerly Propionibacterium acnes) with the broth microdilution method. Formulations containing SP 70 surfactant with TC showed the most favorable dissolution profiles and were found to be nontoxic. This composition also showed significant increase in free radical scavenger activity compared to the blank sample and the highest SOD enzyme activity was also detected after treatment with the cream samples. In antibacterial studies, significant differences were observed between the treated and control groups after an incubation time of 6 h.

The diamide insecticide chlorantraniliprole increases the single-channel current activity of the mammalian skeletal muscle ryanodine receptor.

Very recently, the diamide insecticide chlorantraniliprole was shown to induce Ca2+-release from sarcoplasmic reticulum (SR) vesicles isolated from mammalian skeletal muscle through the activation of the SR Ca2+ channel ryanodine receptor. As this result raises severe concerns about the safety of this chemical, we aimed to learn more about its action. To this end, single-channel analysis was performed, which showed that chlorantraniliprole induced high-activity bursts of channel opening that accounts for the Ca2+-releasing action described before.

Lithocholic acid, a bacterial metabolite reduces breast cancer cell proliferation and aggressiveness.

Our study aimed at finding a mechanistic relationship between the gut microbiome and breast cancer. Breast cancer cells are not in direct contact with these microbes, but disease could be influenced by bacterial metabolites including secondary bile acids that are exclusively synthesized by the microbiome and known to enter the human circulation. In murine and bench experiments, a secondary bile acid, lithocholic acid (LCA) in concentrations corresponding to its tissue reference concentrations (< 1 µM), reduced cancer cell proliferation (by 10-20%) and VEGF production (by 37%), aggressiveness and metastatic potential of primary tumors through inducing mesenchymal-to-epithelial transition, increased antitumor immune response, OXPHOS and the TCA cycle. Part of these effects was due to activation of TGR5 by LCA. Early stage breast cancer patients, versus control women, had reduced serum LCA levels, reduced chenodeoxycholic acid to LCA ratio, and reduced abundance of the baiH (7α/ß-hydroxysteroid dehydroxylase, the key enzyme in LCA generation) gene in fecal DNA, all suggesting reduced microbial generation of LCA in early breast cancer.

Conservation and the 4 Rs, which are rescue, rehabilitation, release, and research.

Vertebrate animals can be injured or threatened with injury through human activities, thus warranting their "rescue." Details of wildlife rescue, rehabilitation, release, and associated research (our 4 Rs) are often recorded in large databases, resulting in a wealth of available information. This information has huge research potential and can contribute to understanding of animal biology, anthropogenic impacts on wildlife, and species conservation. However, such databases have been little used, few studies have evaluated factors influencing success of rehabilitation and/or release, recommended actions to conserve threatened species have rarely arisen, and direct benefits for species conservation are yet to be demonstrated. We therefore recommend that additional research be based on data from rescue, rehabilitation, and release of animals that is broader in scope than previous research and would have community support.

Assessment of cerebral circulation in a porcine model of intravenously given E. coli induced fulminant sepsis.

BACKGROUND: The aim of the present work was to assess cerebral hemodynamic changes in a porcine model of E.coli induced fulminant sepsis. METHODS: Nineteen healthy female Hungahib pigs, 10-12 weeks old, randomly assigned into two groups: Control (n = 9) or Septic Group (n = 10). In the Sepsis group Escherichia coli culture suspended in physiological saline was intravenously administrated in a continuously increasing manner according to the following protocol: 2 ml of bacterial culture suspended in physiological saline was injected in the first 30 min, then 4 ml of bacterial culture was administered within 30 min, followed by infusion of 32 ml bacterial culture for 2 h. Control animals received identical amount of saline infusion. Systemic hemodynamic parameters were assessed by PiCCo monitoring, and cerebral hemodynamics by transcranial Doppler sonography (transorbital approach) in both groups. RESULTS: In control animals, systemic hemodynamic variables and cerebral blood flow velocities and pulsatility indices were relatively stable during the entire procedure. In septic animals shock developed in 165 (IQR: 60-255) minutes after starting the injection of E.coli solution. Blood pressure values gradully decreased, whereas pulse rate increased. A decrease in cardiac index, an increased systemic vascular resistance, and an increased stroke volume variation were observed. Mean cerebral blood flow velocity in the middle cerebral artery did not change during the procedure, but pulsatility index significantly increased. CONCLUSIONS: There is vasoconstriction at the level of the cerebral arterioles in the early phase of experimental sepsis that overwhelmes autoregulatory response. These results may serve as additional pathophysiological information on the cerebral hemodynamic changes occurring during the septic process and may contribute to a better understanding of the pathomechanism of septic encephalopathy.

Highly potent dUTPase inhibition by a bacterial repressor protein reveals a novel mechanism for gene expression control.

Transfer of phage-related pathogenicity islands of Staphylococcus aureus (SaPI-s) was recently reported to be activated by helper phage dUTPases. This is a novel function for dUTPases otherwise involved in preservation of genomic integrity by sanitizing the dNTP pool. Here we investigated the molecular mechanism of the dUTPase-induced gene expression control using direct techniques. The expression of SaPI transfer initiating proteins is repressed by proteins called Stl. We found that Φ11 helper phage dUTPase eliminates SaPIbov1 Stl binding to its cognate DNA by binding tightly to Stl protein. We also show that dUTPase enzymatic activity is strongly inhibited in the dUTPase:Stl complex and that the dUTPase:dUTP complex is inaccessible to the Stl repressor. Our results disprove the previously proposed G-protein-like mechanism of SaPI transfer activation. We propose that the transfer only occurs if dUTP is cleared from the nucleotide pool, a condition promoting genomic stability of the virulence elements.