The leaf secretory scales of <Emphasis Type="Italic">Combretum molle</Emphasis> (Combretaceae): morphology,ultrastructure and histochemistry

This paper reports the results of a study on the morphology, mode of secretion, ultrastructure and histochemistry of leaf secretory scales of Combretum molle using both light and electron microscopy. The density of the secretory scales is higher on the abaxial leaf surface in the intervein areas. Each secretory scale is made up of a basal epidermal cell, a short bicellular stalk and a multicellular umbrella-like head comprising 8–24 cells. The secretion is released from each head cell into the subcuticular space through a lateral ostiole, and then onto the leaf surface via a central pore on each scale. This secretion mechanism is described in this study for the first time in family Combretaceae. Ultrastructural characteristics of scale cells display the typically active metabolism of secretory systems. Preliminary histochemical investigations show that these scales contain lipids, terpenoids, phenolics, flavonoids and alkaloids which probably offer anti-microbial and anti-herbivore protection.     

Short-term response of wild grapevines (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L<Emphasis Type="Italic">. ssp. sylvestris</Emphasis>) to NaCl salinity exposure: changes of some physiological and molecular characteristics

The physiological and molecular response to salt stress was studied in two wild grapevine (Vitis vinifera L. ssp. sylvestris or Vitis sylvestris) accessions “Khédhayria” and “Houamdia”, previously identified as salt-tolerant and salt-sensitive pair wise. Plants from both accessions were subjected to a progressive salt stress by the use of a nutritional solution containing up to 150 mM NaCl for 2 weeks. Salt stress adversely affected growth and water potential since the first day of exposure to 150 mM NaCl. However, chlorophyll fluorescence parameters were unchanged until 14 days of salt exposure. At that time point the predawn water potential (Ψ_PD), the non-photochemical quenching of fluorescence (NPQ) and the coefficient of photochemical quenching (q_p) were significantly less altered in the tolerant accession. At the molecular level semi-quantitative RT-PCR assays revealed a differential expression of (Vs α-gal/SIP and Vs DHN) genes within these contrasting accessions after exposure to 24 h and 14 days of salt. Comparably, the Vs RD22 gene had increased slightly after only 14 days of treatment in both accessions. These results were the first pieces of information reported on the early and late regulation of salt response genes in wild grapevines. Furthermore, genotype-dependent parameters such as NPQ, q_p, mRNA levels of Vs α-gal/SIP and Vs DHN could be used to screen salt-tolerant wild grapevine genotypes.     

Early and Non-Invasive Detection of Chronic Wasting Disease Prions in Elk Feces by Real-Time Quaking Induced Conversion

Chronic wasting disease (CWD) is a fatal prion disease of wild and captive cervids in North America. Prions are infectious agents composed of a misfolded version of a host-encoded protein, termed PrP^Sc. Infected cervids excrete and secrete prions, contributing to lateral transmission. Geographical distribution is expanding and case numbers in wild cervids are increasing. Recently, the first European cases of CWD have been reported in a wild reindeer and two moose from Norway. Therefore, methods to detect the infection early in the incubation time using easily available samples are desirable to facilitate effective disease management. We have adapted the real-time quaking induced conversion (RT-QuIC) assay, a sensitive in vitro prion amplification method, for pre-clinical detection of prion seeding activity in elk feces. Testing fecal samples from orally inoculated elk taken at various time points post infection revealed early shedding and detectable prion seeding activity throughout the disease course. Early shedding was also found in two elk encoding a PrP genotype associated with reduced susceptibility for CWD. In summary, we suggest that detection of CWD prions in feces by RT-QuIC may become a useful tool to support CWD surveillance in wild and captive cervids. The finding of early shedding independent of the elk’s prion protein genotype raises the question whether prolonged survival is beneficial, considering accumulation of environmental prions and its contribution to CWD transmission upon extended duration of shedding.     

Mechanisms Underpinning Increased Plasma Creatinine Levels in Patients Receiving Vemurafenib for Advanced Melanoma

Context

Serum creatinine has been reported to increase in patients receiving Vemurafenib, yet neither the prevalence nor the mechanism of this adverse event are known.

Objective

We aimed to evaluate the frequency and the mechanisms of increases in plasma creatinine level in patients receiving Vemurafenib for advanced melanoma.

Methods

We performed a retrospective monocentric study including consecutive patients treated with Vemurafenib for an advanced melanoma. We collected clinical and biological data concerning renal function before introduction of Vemurafenib and in the course of monthly follow-up visits from March 2013 to December 2014. Cystatin C-derived glomerular filtration rate was evaluated before and after Vemurafenib initiation, as increase in serum cystatin C is specific to a decrease in the glomerular filtration rate. We also performed thorough renal explorations in 3 patients, with measurement of tubular secretion of creatinine before and after Vemurafenib initiation and a renal biopsy in 2 patients.

Results

70 patients were included: 97% of them displayed an immediate, and thereafter stable, increase in creatinine (+22.8%) after Vemurafenib initiation. In 44/52 patients in whom Vemurafenib was discontinued, creatinine levels returned to baseline. Serum cystatin C increased, although proportionally less than serum creatinine, showing that creatinine increase under vemurafenib was indeed partly due to a renal function impairment. In addition, renal explorations demonstrated that Vemurafenib induced an inhibition of creatinine tubular secretion.

Conclusion

Thus, Vemurafenib induces a dual mechanism of increase in plasma creatinine with both an inhibition of creatinine tubular secretion and slight renal function impairment. However, this side effect is mostly reversible when Vemurafenib is discontinued, and should not lead physicians to discontinue the treatment if it is effective.     

Antischistosomal and liver protective effects of Curcuma longa extract in Schistosoma mansoni infected mice

With a view to clarify the induction of the "Crabtree consequence" in liver cells of S. mansoni infected mice, the curative effect of oil extract of C. longa was tested and compared to praziquantel (PZQ) the effective drug against all schistosome species occurring in man. Protein, glucose, glucose-6-phopsphatase, AMP-deaminase, adensoine deaminase, urea concentration, pyravate kinase (PK), phosphoenol pyruvate carboxykinase (PEPCK) and PK/PEPCK ratio were estimated. In addition, worm burden and ova count in mice infected with S. mansoni were elucidated. The result showed that C. longa normalized the concentration of protein, glucose, AMP-deaminase and adenosine deaminase, which were changed by infection. Moreover, it lowered pyruvate kinase level, while PZQ-treatment induced more elevation of this enzyme. PZQ was more effective in lowering worm burden while C. longa extract was more potent in reducing egg count.     

A pandemic strain of calicivirus threatens rabbit industries in the Americas

The filoviruses, Ebola (EBOV) and Marburg (MARV), cause a lethal hemorrhagic fever. Human isolates of MARV are not lethal to immmunocompetent adult mice and, to date, there are no reports of a mouse-adapted MARV model. Previously, a uniformly lethal EBOV-Zaire mouse-adapted virus was developed by performing 9 sequential passages in progressively older mice (suckling to adult). Evaluation of this model identified many similarities between infection in mice and nonhuman primates, including viral tropism for antigen-presenting cells, high viral titers in the spleen and liver, and an equivalent mean time to death. Existence of the EBOV mouse model has increased our understanding of host responses to filovirus infections and likely has accelerated the development of countermeasures, as it is one of the only hemorrhagic fever viruses that has multiple candidate vaccines and therapeutics. Here, we demonstrate that serially passaging liver homogenates from MARV-infected severe combined immunodeficient (scid) mice was highly successful in reducing the time to death in scid mice from 50–70 days to 7–10 days after MARV-Ci67, -Musoke, or -Ravn challenge. We performed serial sampling studies to characterize the pathology of these scid mouse-adapted MARV strains. These scid mouse-adapted MARV models appear to have many similar properties as the MARV models previously developed in guinea pigs and nonhuman primates. Also, as shown here, the scid-adapted MARV mouse models can be used to evaluate the efficacy of candidate antiviral therapeutic molecules, such as phosphorodiamidate morpholino oligomers or antibodies.     

Screening of lactic starter from Tunisian fermented vegetables and application for the improvement of caper (Capparis spinosa) fermentation through an experimental factorial design

This study aims at designing a lactic starter for caper fermentation isolated from Tunisian fermented vegetables to improve the process and produce consistent and high-quality product. In this study, the lactic starter was isolated by exploring the lactic acid bacteria (LAB) of Tunisian artisanal fermented vegetables. Identification was carried out by partial 16S rRNA gene sequencing. Screening was based on salt tolerance and antagonistic activities against Escherichia coli ATCC 10536 and Enterococcus faecalis ATCC 10541. Caper fermentation was optimized through a full factorial experimental design (23), by exploring three factors: starter inoculum size, NaCl concentration, and acetate content. Differences in pH values, Total aerobic mesophilic bacteria and LAB counts between the beginning and end of fermentation are selected as responses and corresponding regression coefficients were calculated. The lactic microbiota is mainly represented by Lactobacillus plantarum group. Based on salt tolerance and antimicrobial activity, the strain Lactobacillus plantarum F3 was selected as starter for caper fermentation. The effect of NaCl concentration, acetate content, and inoculum size on acidity, total aerobic mesophilic bacteria count, and LAB count after 1 week and 1 month of caper fermentation was studied. Depending on the fermentation time, either 1 week or 1 month, the initial conditions should comprise 0% acetate, 108 CFU/mL inoculum, and 5% NaCl for 1 week against 5% acetate, 107 CFU/mL inoculum, and 10% NaCl for 1 month lasting caper fermentation. A protocol for caper fermentation was set up ensuring hygienic quality and LAB viability. Lb. plantarum F3 was selected as lactic starter for caper fermentation, and initial fermentation conditions were optimized through a full factorial design. This work has shown loss in LAB viability after 1 week of fermentation. Based on results obtained, an optimized fermentation protocol was set up. This protocol ensures LAB survival and high hygienic quality of the product.     

Lipogenesis in arterial wall and vascular smooth muscular cells: regulation and abnormalities in insulin-resistance

Background

Vascular smooth muscular cells (VSMC) express lipogenic genes. Therefore in situ lipogenesis could provide fatty acids for triglycerides synthesis and cholesterol esterification and contribute to lipid accumulation in arterial wall with aging and during atheroma.

Methods

We investigated expression of lipogenic genes in human and rat arterial walls, its regulation in cultured VSMC and determined if it is modified during insulin-resistance and diabetes, situations with increased risk for atheroma.

Results

Zucker obese (ZO) and diabetic (ZDF) rats accumulated more triglycerides in their aortas than their respective control rats, and this triglycerides content increased with age in ZDF and control rats. However the expression in aortas of lipogenic genes, or of genes involved in fatty acids uptake, was not higher in ZDF and ZO rats and did not increase with age. Expression of lipogenesis-related genes was not increased in human arterial wall (carotid endarterectomy) of diabetic compared to non-diabetic patients. In vitro, glucose and adipogenic medium (ADM) stimulated moderately the expression and activity of lipogenesis in VSMC from control rats. LXR agonists, but not PXR agonist, stimulated also lipogenesis in VSMC but not in arterial wall in vivo. Lipogenic genes expression was lower in VSMC from ZO rats and not stimulated by glucose or ADM.

Conclusion

Lipogenic genes are expressed in arterial wall and VSMC; this expression is stimulated (VSMC) by glucose, ADM and LXR agonists. During insulin-resistance and diabetes, this expression is not increased and resists to the actions of glucose and ADM. It is unlikely that this metabolic pathway contribute to lipid accumulation of arterial wall during insulin-resistance and diabetes and thus to the increased risk of atheroma observed in these situations.     

Chromium Chloride Administration Causes a Substantial Reduction of Coronary Lipid Deposits,Aortic Lipid Deposits,and Serum Cholesterol Concentration in Rabbits

This experiment was carried out to test the null hypothesis that intramuscular trivalent chromium administration would not remove lipids from the heart and ascending aorta of the hyoercholesterolemic rabbits and would not lower their serum cholesterol levels. A novel computer-based method, previously described, was used to assess the sizes of the intracardiac and aortic lesions. Clinical chemistry and histopathology were performed through routine methods. The sizes of the lipid deposits in the coronary vasculature of the hypercholesterolemic rabbits were greatly reduced as a result of the intramuscular chromium chloride injections. Lipid deposits in the ascending aorta were similarly reduced, as well as the serum cholesterol concentrations. The terminal serum chromium concentrations in the chromium-treated group were in the range of 3,258–4,513 μg/L, whereas, in the untreated animals, the concentrations were 3.2 to 6.3 μg/L. The general condition of the chromium-treated animals was good and they were continuing to gain weight up to the time they were killed. However, it was found that their liver function tests had become abnormal even though there was no evidence of hepatic histopathological lesions specifically affecting the chromium-treated group. The kidney function tests and histopathology were normal. These findings suggest that a more aggressive approach than those tried hitherto might be useful in treating atherosclerotic human patients with chromium.     

Pathological studies on postvaccinal reactions of Rift Valley fever in goats

Background

Multiple short hairpin RNA (shRNA) gene therapy strategies are currently being investigated for treating viral diseases such as HIV-1. It is important to use several different shRNAs to prevent the emergence of treatment-resistant strains. However, there is evidence that repeated expression cassettes delivered via lentiviral vectors may be subject to recombination-mediated repeat deletion of 1 or more cassettes.

Results

The aim of this study was to determine the frequency of deletion for 2 to 6 repeated shRNA cassettes and mathematically model the outcomes of different frequencies of deletion in gene therapy scenarios. We created 500+ clonal cell lines and found deletion frequencies ranging from 2 to 36% for most combinations. While the central positions were the most frequently deleted, there was no obvious correlation between the frequency or extent of deletion and the number of cassettes per combination. We modeled the progression of infection using combinations of 6 shRNAs with varying degrees of deletion. Ourin silico modeling indicated that if at least half of the transduced cells retained 4 or more shRNAs, the percentage of cells harboring multiple-shRNA resistant viral strains could be suppressed to < 0.1% after 13 years. This scenario afforded a similar protection to all transduced cells containing the full complement of 6 shRNAs.

Conclusion

Deletion of repeated expression cassettes within lentiviral vectors of up to 6 shRNAs can be significant. However, our modeling showed that the deletion frequencies observed here for 6× shRNA combinations was low enough that thein vivo suppression of replication and escape mutants will likely still be effective.