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Apicomplexan parasites possess secretory organelles called rhoptries that undergo regulated exocytosis upon contact with the host. This process is essential for the parasitic lifestyle of these pathogens and relies on an exocytic machinery sharing structural features and molecular components with free-living ciliates. However, how the parasites coordinate exocytosis with host interaction is unknown. Here, we performed a Tetrahymena-based transcriptomic screen to uncover novel exocytic factors in Ciliata and conserved in Apicomplexa. We identified membrane-bound proteins, named CRMPs, forming part of a large complex essential for rhoptry secretion and invasion in Toxoplasma. Using cutting-edge imaging tools, including expansion microscopy and cryo-electron tomography, we show that, unlike previously described rhoptry exocytic factors, TgCRMPs are not required for the assembly of the rhoptry secretion machinery and only transiently associate with the exocytic site-prior to the invasion. CRMPs and their partners contain putative host cell-binding domains, and CRMPa shares similarities with GPCR proteins. Collectively our data imply that the CRMP complex acts as a host-molecular sensor to ensure that rhoptry exocytosis occurs when the parasite contacts the host cell., (© 2022 The Authors. Published under the terms of the CC BY 4.0 license.)

Food processing affects the structure and chemical state of proteins. In particular, protein oxidation occurs and may impair protein properties. These chemical reactions initiated during processing can develop during digestion. Indeed, the physicochemical conditions of the stomach (oxygen pressure, low pH) favor oxidation. In that respect, digestive proteases may be affected as well. Yet, very little is known about the link between endogenous oxidation of digestive enzymes, their potential denaturation, and, therefore, food protein digestibility. Thus, the objective of this study is to understand how oxidative chemical processes will impact the pepsin secondary structure and its hydrolytic activity. The folding and unfolding kinetics of pepsin under oxidative conditions was determined using Synchrotron Radiation Circular Dichroism. SRCD gave us the possibility to monitor the rapid kinetics of protein folding and unfolding in real-time, giving highly resolved spectral data. The proteolytic activity of control and oxidized pepsin was investigated by MALDI-TOF mass spectrometry on a meat protein model, the creatine kinase. MALDI-TOF MS allowed a rapid evaluation of the proteolytic activity through peptide fingerprint. This study opens up new perspectives by shifting the digestion paradigm taking into account the gastric digestive enzyme and its substrate.

It is well known that some patients present with "more than severe" tricuspid regurgitation (TR). We aimed to assess the prognosis of these very severe TR patients. We defined very severe TR using 3 simple echocardiographic parameters: a coaptation gap≥10mm, a laminar TR flow and a systolic reversal of the hepatic vein flow. We included 259 consecutive patients (76 ± 13 years; 46% men) with moderate-to-severe TR (n = 114) and severe TR (n = 145). The primary end point was the combination of hospitalisation for right heart failure (RHF) and cardiovascular mortality. Median follow-up was 24(7 to 47) months. In patients with severe TR, 52 (36%) met the definition of very severe TR. These patients were younger, had more history of RHF and were more frequently treated with loop diuretics than those with moderate-to-severe TR (all p < 0.001). Four-year event-free survival rates were 68 ± 5%, for moderate-to-severe TR, 48 ± 6% for severe TR and only 35 ± 7% for very-severe TR (p < 0.001). On multivariable analysis, after adjustment for outcome predictors including age, comorbidity, RHF, TR etiology, left and right ventricular dysfunction, and tricuspid valve surgery, patients with very severe TR had a worsened prognosis than those with moderate-to-severe TR (Adjusted Hazard Ratio [95% Confidence Interval] = 2.43 [1.18 to 5.53]; p = 0.002) and than those with severe TR (Adjusted Hazard Ratio [95% Confidence Interval] = 2.23 [1.06 to 5.56]; p = 0.015). In conclusion, very severe TR is frequent in patients with severe TR, corresponds to a more advanced stage of the disease and is associated with poor outcomes. Therefore, the use of a 5-grade classification of TR severity is justified in routine clinical practice. (ID-RCB: 2017-A03233-50)., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: The authors had for aim to assess the conformity of antibiotic prescription with guidelines, for the management of community-acquired pneumonia, in a French University Hospital., Design: This prospective study included adults patients hospitalized for pneumonia over a period of six months. The attending physician estimated the severity of pneumonia. The adequacy to guidelines focused on: first antibiotic choice and prescription modality, antibiotic choice in case of treatment modification at 48 to 72 hours, and duration of antibiotherapy., Results: A hundred and nine cases of pneumonia were included in 106 patients. The mean age was 66 years, the mortality rate was 17 %. Bacterial documentation was recorded in 40.4 % of cases. The first antibiotics used were in accordance with guidelines in 52.3 % of cases. The non conformity rate was minor in 55.8 % of cases. Antibiotherapies putting the patient at risk were used in less than 10 % of the cases. The rate of antibiotic modification at 48 to 72 hours was 46.8 %, primarily for bacteriological purposes (35.3 %) or initial treatment failure (27.4 %). The treatment duration was inappropriate in 52.7 % of cases and generally too long in case of non conformity., Conclusion: It seems important to support guideline information, training of prescribers, and to consult an antibiotic expert., ((c) 2010 Elsevier Masson SAS. All rights reserved.)

A PCR-based technique using new fluorescent probes, called molecular beacons, was developed to detect the antifolate resistance-associated S108N point mutation in Plasmodium falciparum. One hundred African clinical isolates were tested by the new method in comparison with the PCR-restriction fragment length polymorphism method. This new molecular technique appears to be a promising tool for epidemiological studies.

The correlation between the structure of two short sequences from the Plasmodium falciparum cg2 gene and parasite chloroquine susceptibility was evaluated in unselected clinical isolates obtained from travellers returning mainly from Africa to France in 1995 and 1996. As determined by an isotopic semi-microtest, 74 isolates were susceptible to chloroquine (50% inhibitory concentration < 80 nM), 13 were intermediate (80 nM < 50% inhibitory concentration < 110 nM) and 53 were resistant (50% inhibitory concentration > 110 nM). Two polymerase chain reaction assays were developed, one for the kappa and one for the omega repeat domains of cg2 gene. The kappa and the omega repeat domains of 99 isolates were sequenced. A variation in the unit number of kappa and omega repeats was observed. Variations in repetitive sequences, which were not previously described, were found: three for the kappa repeat region: kappa9; kappa10 and kappa11 and three for the omega repeat region: omega8; omega9 and omega22. A polymorphism was observed inside the repeat units of kappa and omega regions. There were six possible kappa repeat units and seven possible omega repeat units. The presence of a particular pattern, containing kappa14 and omega16 repeat units, was associated with a lack of chloroquine susceptibility in 44 out of 46 cases. However, not all resistant isolates had this 'resistant' genotype. Among 43 resistant isolates, 36 (84%) had the kappa14 repeats sequence and 36 had the omega16 repeats sequence. These results lend further support to linkage between cg2 polymorphisms and chloroquine resistance without excluding the existence of other resistance component(s).