Orobanche foetida resistance in two new faba bean genotypes produced by radiation mutagenesis

Purpose: Broomrape produces serious damage to many legume crops and, particularly, becomes a limiting factor for faba bean (Vicia faba L.) production in the Mediterranean basin. Currently, several traditional methods of control have been developed, but none has proved to be effective for this parasite. However, breeding for resistance to this pest remains as one of the most feasible and environment-friendly methods for managing broomrape, but the mechanisms governing the interaction between the parasite and the host are not yet well understood. Therefore, we studied the behavior and molecular and enzymatic changes associated with the resistance to Orobanche foetida in faba bean mutants, which were obtained through radiation mutagenesis.

Materials and methods: Three faba bean genotypes were used in this study, the variety ‘Badï’, characterized by high productivity in Orobanche-free soils and susceptibility to O. foetida, and two mutant lines P2M3 and P7M3 (derived from radio mutagenesis program), selected for their higher resistance to O. foetida in a field evaluation. The infection progress and the relative changes in the co-culture response, the enzymatic activities changes and the efficiency of the root extract stimulants from the host plant were followed and evaluated in all the genotypes.

Results: Experiments showed that low induction of seed germination is a major component of resistance in these lines against O. foetida. This is confirmed by the in vitro experiments with root exudates. The parallel reduction in infection was accompanied by the continuous enhancement of the peroxidase activity, the polyphenol oxidase activity and the phenylalanine ammonia lyase activity in faba bean roots.

Conclusion: These data suggest the contribution of these enzymes in faba bean resistance to O. foetida broomrape induced by the use of gamma rays. Management of Orobanche by way of crop selection, based on these enzyme systems is a possible option.     

Markers Associated with COVID-19 Susceptibility,Resistance, and Severity

In December 2019, the latest member of the coronavirus family, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in Wuhan, China, leading to the outbreak of an unusual viral pneumonia known as coronavirus disease 2019 (COVID-19). COVID-19 was then declared as a pandemic in March 2020 by the World Health Organization (WHO). The initial mortality rate of COVID-19 declared by WHO was 2%; however, this rate has increased to 3.4% as of 3 March 2020. People of all ages can be infected with SARS-CoV-2, but those aged 60 or above and those with underlying medical conditions are more prone to develop severe symptoms that may lead to death. Patients with severe infection usually experience a hyper pro-inflammatory immune reaction (i.e., cytokine storm) causing acute respiratory distress syndrome (ARDS), which has been shown to be the leading cause of death in COVID-19 patients. However, the factors associated with COVID-19 susceptibility, resistance and severity remain poorly understood. In this review, we thoroughly explore the correlation between various host, viral and environmental markers, and SARS-CoV-2 in terms of susceptibility and severity.     

Eyelid Skin Involvement in Pemphigus Foliaceus

Purpose: To report the involvement of eyelid skin in a patient with pemphigus foliaceus. Methods: Retrospective, interventional case report of a patient with pemphigus foliaceus involving both eyelids. The diagnosis of pemphigus foliaceus was based on histopathology and confirmed by direct immunofluorescence and immunoblot. Failure to respond to conventional immunosuppressive therapy, including high-dose corticosteroids, methotrexate, azathioprine, dapsone, and mycophenolate mofetil, necessitated the use of intravenous immunoglobulin (IVIg) therapy. Results: After successful treatment with IVIg, no change in visual acuity or other sequelae secondary to ocular pemphigus foliaceus were observed. Normal ocular architecture was maintained. Clinical remission was observed after successful therapy. Conclusions: Pemphigus foliaceus involves the skin of the eyelid and does not involve the conjunctiva. The patient did not respond to conventional immunosuppressive therapy. The use of IVIg as mono-therapy resulted in long-term clinical remission.     

Modulation of calcium signaling by interleukin-13 in human airway smooth muscle: role of CD38/cyclic adenosine diphosphate ribose pathway

CD38/cyclic adenosine diphosphate ribose (cADPR) signaling plays an important role in the regulation of intracellular calcium responses to agonists in a variety of cells, including airway smooth muscle (ASM) cells. The present study was aimed at determining the effect of interleukin (IL)-13, a cytokine implicated in the pathogenesis of asthma, on CD38/cADPR signaling and to ascertain the contribution of CD38/cADPR signaling to IL-13-induced airway hyperresponsiveness. Human ASM cells maintained in culture were exposed to 50 ng/ml IL-13 for 22 h and levels of CD38 expression and intracellular calcium responses to agonists were measured. Treatment of human ASM cells with IL-13 resulted in increased CD38 expression as determined by real-time polymerase chain reaction, Western blot analysis, and indirect immunofluorescence. Increased CD38 expression was reflected as increased ADP-ribosyl cyclase activity in the ASM cell membranes. The net intracellular calcium responses to bradykinin, thrombin, and histamine were significantly (P < or = 0.05) higher in cells treated with IL-13 compared with controls. Furthermore, 8-bromo-cADPR, a cADPR antagonist, attenuated IL-13-induced augmented intracellular calcium responses to agonists in human ASM cells. These findings indicate that the CD38/cADPR-dependent pathway has a major role in IL-13-induced modulation of calcium signaling in human ASM.     

Relative contribution of different transmembrane segments to the CFTR chloride channel pore

The membrane-spanning part of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl^? channel comprises 12 transmembrane (TM) α-helices, arranged in 2 symmetrical groups of 6. However, those TMs that line the channel pore are not completely defined. We used patch clamp recording to compare the accessibility of cysteine-reactive reagents to cysteines introduced into different TMs. Several residues in TM11 were accessible to extracellular and/or intracellular cysteine reactive reagents; however, no reactive cysteines were identified in TMs 5 or 11. Two accessible residues in TM11 (T1115C and S1118C) were found to be more readily modified from the extracellular solution in closed channels, but more readily modified from the intracellular solution in open channels, as previously reported for T338C in TM6. However, the effects of mutagenesis at S1118 (TM11) on a range of pore functional properties were relatively minor compared to the large effects of mutagenesis at T338 (TM6). Our results suggest that the CFTR pore is lined by TM11 but not by TM5 or TM7. Comparison with previous works therefore suggests that the pore is lined by TMs 1, 6, 11, and 12, suggesting that the structure of the open channel pore is asymmetric in terms of the contributions of different TMs. Although TMs 6 and 11 appear to undergo similar conformational changes during channel opening and closing, the influence of these two TMs on the functional properties of the narrowest region of the pore is clearly unequal.     

Presacral ganglioneuroma in an 8-year-old child: case report,and literature review

Ganglioneuromas are benign tumors of the sympathetic nervous system, rarely found in the presacral region. In this study, we report the case of presacral ganglioneuroma in an 8-year-old girl, who complained of abdominal pain with diarrhea and abdominal distension. Ultrasound showed a large hypoechoic pelvic mass complicated by right ureter hydronephrosis. the CT and MRI confirm the presence of a presacral tissue mass with heterogeneous enhancement after contrast injection. The child underwent a complete surgical resection, and the anatomopathological study returned in favor of a ganglioneuroma. The presacral ganglioneuroma is an extremely rare tumor in that only twenty cases have been reported in the literature. 3 of which were less than 8-years-old. Through our case, we will review the epidemiological, clinical, radiological and therapeutic characteristics of this type of tumor.     

In patients on prolonged HAART,a significant pool of HIV infected CD4 T cells are HIV-specific

OBJECTIVES: To examine the antigen specificities of HIV reservoir CD4 T cells in patients on prolonged and effective highly active antiretroviral therapy (HAART). DESIGN: Five HIV-infected patients, who were highly adherent to antiretroviral treatment, were selected on the basis of long-term undetectable plasma viral RNA on unmodified HAART. To investigate the antigen specificities of infected memory CD4 T cells, we examined the capacity of recall antigens, including HIV antigens, to induce virus production by peripheral blood mononuclear cells (PBMC). METHODS: To quantify CD4 T cells infected by replication-competent virus, and to determine their antigen specificities, we used a limiting dilution-based culture assay. CD8 T cell-depleted PBMC at several cell densities were activated by using Tuberculin purified protein derivative, cytomegalovirus, or HIV-1 p24 with and without HIV-1 Nef. RESULTS: We found that the pool of infected CD4 T cells includes HIV-specific cells with apparent frequencies between 5- and 100-fold higher than those of the common specificities for cytomegalovirus or Tuberculin. CONCLUSION: Our findings suggest that a significant proportion of replication-competent HIV-infected CD4 T cells in these patients are memory cells directed against HIV determinants. This may provide a rationale for the therapeutic use of recombinant HIV antigens to reduce the pool of HIV-reservoir cells.