Influence of Culture Media and Environmental Factors (Water Potential and Temperature) on Mycelial Growth of Phytopythium vexans (de Bary), the Causal Agent of Dieback Disease in Apple Trees

This study aimed at evaluating the effects of culture media and environmental factors (temperature and water potential (Ψw)) on the growth of the pathogenic fungus Phytopythium vexans (de Bary) associated with root rot and dieback disease in apple trees. Tomato agar, potato dextrose agar (PDA), and soybean agar were the most favourable for rapid mycelial growth, with optimum growth recorded for PDA medium. To determine the environmental conditions that promoted the development of this phytopathogen, the effects of temperature (5–30 °C), water potential (Ψw) (−15.54; −0.67 MPa) (0.89–0.995 aw), and their interaction were evaluated on the in vitro radial growth rates of the five isolates of P. vexans and on their latency phase (time period prior to growth). The results of this study showed that temperature, water potential, and their interaction had significant effects (p < 0.001) on the radial growth rates and latency phases of all tested P. vexans isolates. All isolates were able to grow throughout the temperature range (5 to 30 °C), with the maximum radial growth rate being observed at the highest temperatures, 25–30 °C. Growth was seen to be faster at −0.67 MPa (0.995 aw) at 25 °C and 30 °C. No growth was observed at Ψw < −5.44 MPa (0.96 aw), regardless of the temperature. It was found that the length of the latency phase depended significantly on both environmental factors. The longest latency phases (5 days on average) were recorded at a temperature of 5 °C and Ψw of −0.67 MPa (0.995 aw) and −2.69 MPa (0.98 aw), while the shortest latency phases were observed at a temperature of 30 °C and a Ψw of −0.67 MPa (0.995 aw), with an average of 0.2 days. The findings from this study could help to understand the impact of these environmental factors on the occurrence of diseases caused by P. vexans and more likely to design a reliable preventive control strategy based on the avoidance of conditions that play in favour of the phytopathogen

Linking Urban Water Management, Wastewater Recycling, and Environmental Education: A Case Study on Engaging Youth in Sustainable Water Resource Management in a Public School in Casablanca City, Morocco

The management of water resources is crucial for sustainable development, necessitating innovative solutions to address the increasing demand for safe water. Alternative approaches must be adopted to effectively engage young generations in understanding the importance of water resources. This chapter reports on an experiment that aimed to promote sustainability education by linking wastewater treatment and reuse with an educational garden. In particular, an undertaking was executed to establish a decentralized wastewater treatment system wherein purified water was employed for the purpose of irrigation. The study’s primary focus is on the association between urban water management, wastewater recycling, and environmental education. The study has two distinct components. The first segment discusses three examples of projects that have employed urban wastewater treatment and reuse to generate environmental education materials using various approaches. The second component features a case study of a public high school in Casablanca, where students participated in a questionnaire and participatory workshops to design an educational garden. The study’s outcomes include a proposed educational garden design that will be presented to the relevant authorities and project partners

Congenital cystic adenomatoid malformation – dangers of misdiagnosis: a case report

Abstract Background Congenital cystic adenomatoid malformation is a rare pulmonary malformation, but is the most common lung malformation observed in children. In developing countries, such as Morocco, prenatal diagnosis is missing. Congenital cystic adenomatoid malformation may occur after birth in the presence of complications and needs a computed tomography scan for confirmation. However, our lack of awareness of this malformation has been responsible for a late and wrong diagnosis along with therapeutic errors. We report the first case in Morocco where diagnosis is confirmed by histology after death. Case presentation A 10-month-old Arab boy was prescribed various antibiotics (including anti-staphylococcal) and endured repeated chest drainages, leading to his death just after radiological diagnosis and instant surgery. Conclusions The goal of this case report is to firmly express the need for both pediatricians and radiologists to enlarge diagnosis investigations, especially of congenital or constitutional entities in children, as soon as recurrence of respiratory distress and pulmonary infections are manifested. We also emphasize this important entity because of its frequency, to avoid the eventual therapeutic errors

Vibrio splendidus O-antigen structure: A trade-off between virulence to oysters and resistance to grazers

A major debate in evolutionary biology is whether virulence is maintained as an adaptive trait and/or evolves to non‐virulence. In the environment, virulence traits of non‐obligatory parasites are subjected to diverse selective pressures and trade‐offs. Here we focus on a population of Vibrio splendidus that displays moderate virulence for oysters. A MARTX (Multifunctional‐autoprocessing repeats‐in‐toxin) and a type‐six secretion system (T6SS) were found to be necessary for virulence toward oysters, while a region (wbe) involved in O‐antigen synthesis is necessary for resistance to predation against amoebae. Gene inactivation within the wbe region had major consequences on the O‐antigen structure, conferring lower immunogenicity, competitive advantage and increased virulence in oyster experimental infections. Therefore, O‐antigen structures that favor resistance to environmental predators result in an increased activation of the oyster immune system and a reduced virulence in that host. These trade‐offs likely contribute to maintaining O‐antigen diversity in the marine environment by favoring genomic plasticity of the wbe region. The results of this study indicate an evolution of V. splendidus toward moderate virulence as a compromise between fitness in the oyster as a host, and resistance to its predators in the environment

SFlt-1 elevates blood pressure by augmenting endothelin-1-mediated vasoconstriction in mice.

OBJECTIVE: Scavenging of vascular endothelial growth factor (VEGF) elevates blood pressure (BP) in patients receiving anti-angiogenic therapy. Similarly, inhibition of circulation VEGF by its soluble receptor fms-like tyrosine kinase-1 (sFlt-1) underlies BP elevation in pre-eclampsia. Both phenotypes are characterized by augmented production of endothelin-1 (ET-1), suggesting a role for ET-1 in anti-angiogenic hypertension. We aimed to assess the effect of VEGF inhibition on ET-1-induced contractility and downstream ET-1 signaling. APPROACH AND RESULTS: Male C57BL/6N mice were treated with either sFlt-1 or vehicle and BP was assessed via tail-cuff. Mean arterial pressure of sFlt-1-treated mice markedly increased compared to vehicle-treated controls (N = 11-12, p<0.05). After sacrifice, carotid and mesenteric arteries were isolated for isometric tension measurements. ET-1-induced contractions were similar in mesenteric arteries of vehicle and sFlt-1-treated mice, but augmented in carotid segments of sFlt-1-treated mice compared to controls (N = 9-10, p<0.05). The increased contraction in carotid segments could be completely abrogated by the cyclooxygenase (COX) inhibitor indomethacin (N = 9-10, p<0.05), indicating heightened prostaglandin-mediated vasoconstriction. This was associated with a shift towards procontractile ETB signaling in sFlt-1-treated mice, possibly explaining the increased ET-1-induced prostaglandin-mediated vasoconstriction. In line with the ex vivo findings, sFlt-1-induced BP elevation could be prevented in vivo by oral treatment with either a high-dose of the COX inhibitor aspirin (N = 7) or with picotamide (N = 9), a dual thromboxane A2 synthase inhibitor and receptor antagonist. CONCLUSIONS: VEGF inhibition augments the pressor response to ET-1. The cyclooxygenase-thromboxane signaling route downstream of ET-1 might be a possible target to prevent BP elevation during VEGF inhibition

Resistance of the oyster pathogen Vibrio tasmaniensis LGP32 against grazing by Vannella sp. marine amoeba involves Vsm and CopA virulence factors

International audienceVibrios are ubiquitous in marine environments and opportunistically colonize a broad range of hosts. Strains of Vibrio tasmaniensis present in oyster farms can thrive in oysters during juvenile mortality events and behave as facultative intracellular pathogen of oyster haemocytes. Herein, we wondered whether V. tasmaniensis LGP32 resistance to phagocytosis is specific to oyster immune cells or contributes to resistance to other phagocytes, like marine amoebae. To address this question, we developed an integrative study, from the first description of amoeba diversity in oyster farms to the characterization of LGP32 interactions with amoebae. An isolate of the Vannella genus, Vannella sp. AP1411, which was collected from oyster farms, is ubiquitous, and belongs to one clade of Vannella that could be found associated with Vibrionaceae. LGP32 was shown to be resistant to grazing by Vannella sp. AP1411 and this phenotype depends on some previously identified virulence factors: secreted metalloprotease Vsm and copper efflux p-ATPase CopA, which act at different steps during amoeba-vibrio interactions, whereas some other virulence factors were not involved. Altogether, our work indicates that some virulence factors can be involved in multi-host interactions of V. tasmaniensis ranging from protozoans to metazoans, potentially favouring their opportunistic behaviour

Plasma ceramide is increased and associated with proteinuria in women with pre-eclampsia and HELLP syndrome

Objectives: Ceramide is a sphingolipid with anti-angiogenic and pro-apoptotic properties that has shown to be increased in plasma of women with pre-eclampsia. We aimed to compare plasma and placental sphingolipid content among normotensive pregnant women and pre-eclamptic women with and without HELLP syndrome and we aimed to assess whether ceramide is related to hypertension and proteinuria in pre-eclampsia. Study design: Case-control study. Participants were recruited from the Department of Obstetrics at the Academic Medical Center in Amsterdam, The Netherlands. In total 48 pregnant women were included: 24 with pre-eclampsia and 24 normotensive controls. Of the 24 pre-eclamptic women, 11 had HELLP syndrome. Main outcome measures: Plasma and placental ceramide content and correlation with blood pressure and protein excretion in pre-eclampsia. Results: Total plasma, but not placental, ceramide was higher in pre-eclamptic women with HELLP syndrome (11200 95% CI 9531–12870 nmol/ml, n = 11) compared to pre-eclamptic women without HELLP (7413 95% CI 5928–8898 nmol/ml, n = 13, p < 0.001) and normotensive pregnant women (7404 95% CI 6695–8112 nmol/ml, n = 24, p < 0.001). Maternal circulating ceramide levels were strongly associated with proteinuria (r = 0.621, n = 24, p = 0.001) in pre-eclamptic women and inversely correlated with gestational age at delivery (r = 0.771, p < 0.01) in pre-eclamptic women with HELLP syndrome. Plasma ceramide was not correlated with blood pressure. Conclusion: Plasma but not placental ceramide content is increased in women with pre-eclampsia and HELLP syndrome. The strong positive correlation with proteinuria and the inverse correlation with gestational age at delivery indicate that excess plasma ceramide may contribute to the pathophysiology of pre-eclampsia and HELLP

Role of nitric oxide and the endothelium.

<p>A) Effect of eNOS inhibition with L-NAME (N = 5) and endothelium (EC) denudation (N = 4) on ET-1 concentration-response curves in carotid segments of vehicle-treated mice (Cntrl). Data are expressed as mean±SEM, *(maximal efficacy of Cntrl vs. Cntrl + L-NAME and Cntrl vs. Cntrl + EC denuded, N = 9–5, <i>p</i><0.05). <b>B</b>) Effect of L-NAME (N = 4) and EC denudation (N = 3) on ET-1 concentration-response curves in carotid segments of sFlt-1-treated mice. <b>C</b>) Metacholine concentration-response curve generated after pre-constriction with the α1-adrenergic receptor agonist phenylephrine. Data are expressed as mean±SEM,*(maximal relaxation sFlt-1 vs. Cntrl, N = 13–14, <i>p</i><0.05).</p

mRNA expression of ET_A and ET_B receptors and effect ET_B receptor blockade.

<p>A) Quantitative Real-Time PCR showing thoracic aorta mRNA expression profiles of Ednra and Ednrb in vehicle (Cntrl) and sFlt-1-treated mice normalized to Hprt mRNA levels. Data expressed as mean±SEM, *(Inset figure shows a two-fold increase in high-responders vs. Cntrl, N =  7–13, <i>p</i><0.05), #(high-responders vs. low-responders, N = 7–5, <i>p</i> = 0.06). <b>B</b>) Effect of pre-incubation with the ET_B receptor antagonist BQ788 on endothelin-1 concentration-response curves of carotid segments isolated from vehicle (Cntrl, N = 5) and sFlt-1-treated mice (N = 4). *(maximal efficacy of Cntrl vs. Cntrl + BQ788, N = 5–9, <i>p</i><0.05), $(EC₅₀ of sFlt-1 vs. sFlt-1 + BQ788 and Cntrl vs. Cntrl + BQ788, <i>p</i><0.05)</p

Effect of sFlt-1 on blood pressure.

<p><i>In vivo</i> effect of sFlt-1 or vehicle (Cntrl) infusion during two weeks on mean arterial pressure (MAP). Data are presented as mean±SEM, N = 11–12, (ns) not significant, * <i>p</i><0.05.</p