Leaf anatomy and water loss of in vitro PEG-treated ‘Valiant’ grape

Polyethylene glycol was used to induce water stress of micropropagated Valiant grape. Reduced growth and slow rooting were observed in treated plantlets with 2, 4 and 6% polyethylene glycol as compared to control plantlets with no polyethylene glycol in the rooting medium. At high concentrations of 4 and 6%, leaves exhibited wilting and necrosis. At the 2% level, plantlets recovered and grew satisfactorily. Detached leaves of treated plantlets with 2% polyethylene glycol lost less water than controls when exposed to low humidity for 4 hours. Leaf anatomy of plantlets treated with 2% polyethylene glycol, control (in vitro plantlets) and greenhouse-grown plants were compared under light microscopy. Leaves from control plantlets contained larger mesophyll cells, lacked normal palisade layer formation, had greater intercellular pore spaces and fewer chloroplasts. Leaves from polyethylene glycol-treated plantlets, however, had smaller mesophyll cells, a more defined palisade layer, reduced intercellular pore space and the greatest number of chloroplasts. These results suggest that an osmoticum such as polyethylene glycol may be used to induce more normal leaf anatomy and reduced water loss in micropropagated Valiant grapes.Abbreviations BA 6-benzylaminopurine - FAA formalin-acetol-alcohol - MS Murashige & Skoog (1962) medium - MW molecular weight - NAA napthaleneacetic acid - PEG polyethylene glycol - TBA tertiary butyl alcohol     

Cadmium‐induced toxicity increases prolyl endopeptidase (PREP) expression in the rat testis

During the differentiation of the male gamete, there is a massive remodeling in the shape and architecture of all the cells of the seminiferous epithelium. The cytoskeleton, as well as many associated proteins with it, plays a pivotal role in this process. The testis is particularly susceptible to environmental pollutant, which can lead to injury and impairment of normal spermatozoa production. Cadmium (Cd) is one of the major chemical environmental toxicants in economically developed countries. Food and cigarettes are the main sources of exposure to this element. Here, the protective role of zinc (Zn) to prevent the testicular toxicity in male adult rats after prenatal and during lactation exposure to Cd has been assessed. Altered testicular histology at the interstitial and germinal levels was found, whereas Zn supply completely corrected Cd toxicity. Moreover, the effects of these metals on the testicular expression and localization of the protease prolyl endopeptidase (PREP) were evaluated. Interestingly, the results showed an increase of PREP messenger RNA and protein. Data were corroborated by immunofluorescence. This study raises the possibility of using PREP as a new fertility marker.     

First report of the rare tooth fungus Hericium erinaceus in North African temperate forests

Abstract

The rare fungus Hericium erinaceus (Bull.) Pers. was collected from temperate forests in northwestern Tunisia and described for the first time in Africa. In this paper, we report data about the distribution, ecology, morphology and molecular identification of H. erinaceus. Collected data may help expand our knowledge on this critically endangered rare species worldwide.     

Effects of Cadmium and High Temperature on Some Parameters of Calcium Metabolism in the Killifish (Aphanius fasciatus)

This study aims to investigate the influence of high temperature on cadmium (Cd) toxicity in Aphanius fasciatus (Pisces: Cyprinodontidae). For this reason, Cd, mineral, and organic content in the vertebral column as well as the histological structure of gills and bone were compared in fishes exposed for 30 days to Cd (2 mg/L CdCl₂) and/or high temperature (26 °C). Cd exposure caused a negative correlation between Cd and Ca concentrations (r?=?0.98, p?<?0.05), as well as a significant decrease in inorganic components (p?<?0.05) and ash weight/dry weight ratio (p?<?0.05) in the vertebral column. These changes were accompanied by an increased frequency of histological alterations in gills and bone. Concomitant treatment with Cd and high temperature increases Cd accumulation and Ca depletion in the skeletal tissue and increases the frequency and the severity of histological alterations. These results confirm that temperature increases Cd toxicity and needs to be taken into account for the accurate prediction and assessment of Cd-induced spinal deformities in fish.     

COPD in Nonsmokers: Reports from the Tunisian Population-Based Burden of Obstructive Lung Disease Study

Background

It’s currently well known that smoking and increasing age constitute the most important risk factors for chronic obstructive pulmonary disease (COPD). However, little is known about COPD among nonsmokers. The present study aimed to investigate prevalence, risk factors and the profiles of COPD among nonsmokers based on the Tunisian Burden of Obstructive Lung Disease (BOLD) study.

Methods

807 adults aged 40 years+ were randomly selected from the general population. We collected information about history of respiratory disease, risk factors for COPD and quality of life. Post-bronchodilator spirometry was performed for assessment of COPD. COPD diagnostic was based on the post-bronchodilator FEV₁/FVC ratio, according to the Global Initiative for Obstructive Lung Disease (GOLD) guidelines. The lower limit of normal (LLN) was determined as an alternative threshold for the FEV₁/FVC ratio.

Results and Conclusions

Among 485 nonsmokers, 4.7% met the criteria for GOLD grade I and higher COPD. These proportions were similar even when the LLN was used as a threshold. None of the nonsmokers with COPD reported a previous doctor diagnosis of COPD compared to 7.1% of smokers. Nonsmokers accounted for 45.1% of the subjects fulfilling the GOLD spirometric criteria of COPD. Nonsmokers were predominately men and reported more asthma problems than obstructed smokers. Among nonsmokers significantly more symptoms and higher co-morbidity were found among those with COPD. Increasing age, male gender, occupational exposure, lower body mass index and a previous diagnosis of asthma are associated with increased risk for COPD in nonsmokers. This study confirms previous evidence that nonsmokers comprise a substantial proportion of individuals with COPD. Nonsmokers with COPD have a specific profile and should, thus, receive far greater attention to prevent and treat chronic airway obstruction.     

Chemical composition and antimicrobial activity of the essential oil of Teucrium ramosissimum (Lamiaceae)

The phytochemical composition of the essential oil of Teucrium ramosissimum (aerial parts), harvested in a mountainous region of Tunisia, was analyzed. A total of 68 compounds, accounting for 99.44% of the essential oil, were identified by GC and GC/MS. The major compounds were beta-eudesmol (61; 44.52%), caryophyllene oxide (56; 9.35%), alpha-thujene (1; 5.51%), sabinene (4; 4.71%), and T-cadinol (59; 3.9%). The essential oil, which is being used in Tunisian folk medicine against infectious diseases, was tested for its antimicrobial properties against five different bacteria, and found to have weak to moderate activity, with minimal-inhibitory-concentration (MIC) and minimal-bactericidal-concentration (MBC) values in the range 0.24-0.36 and 1.3-2.9 mg/ml, resp.     

Tc1/Tc2 ratio in the inflammatory process in patients with Behçet's disease

BACKGROUND: Peripheral blood CD8+ T cells expressing interferon gamma and interleukin-4 (IL-4), and lacking CD28 molecules, were responsible for the dynamic interplay between peripheral blood and inflammatory sites. INTRODUCTION: The aim of the current study was to define in Behçet''s disease (BD), CD8+ T-cell subsets using CD28 and CD11b monoclonal antibodies, and the characterization of the Tc1/Tc2 ratio and perforin expression. METHODS: Flow cytometry was used for intracytoplasmic cytokines and perforin expression. Effector cells were investigated by adhesion of CD8+ T cells to human microvascular endothelial cells and by chemotaxis using beta-chemokine. RESULTS: Interferon-gamma-producing CD8+ T cells in active and remission BD patients were increased, which induce a significant increase of the Tc1:Tc2 ratio in BD. CD8(+)CD28(-)CD11b+ T cells were found to be more expanded in BD patients than in age-matched healthy controls. The expression of CD11b molecules in active BD allowed to CD8(+)CD28+/CD8(+)CD28- subsets to adhere to human microvascular endothelial cells, with more efficiency in BD. Using MIP-1alpha, we observed that the migratory process of CD28(-)CD11b(+) is more important in BD. CD28(-)CD11b+ exhibited an increased perforin expression in BD patients. CONCLUSION: Taken together these results suggest the presence of immune activation, probably in response to a profound inflammation affecting BD patients. The physiopathological significance of these results were toward autoimmune diseases and/or infectious process.     

Lebecetin, a potent antiplatelet C-type lectin from Macrovipera lebetina venom

A novel C-type lectin protein (CLP), lebecetin, was purified to homogeneity from the venom of Macrovipera lebetina by gel filtration on a Sephadex G75 column and ion exchange chromatography on Mono S column. Lebecetin is a basic protein with a pHi=9.9 and migrates in SDS-PAGE as a single band or two distinct bands under nonreducing and reducing conditions, respectively. These results are further confirmed by MALDI-TOF mass spectrometry that indicates a molecular mass of 29779 Da for native lebecetin and molecular masses of 15015 and 16296 Da for alpha and beta subunits, respectively. The N-terminal amino acid sequences of lebecetin subunits show a high degree of similarity with those of C-type lectin-like proteins. In addition, functional studies showed that lebecetin has a potent inhibitory effect on platelet aggregation induced by thrombin in a concentration-dependent manner. In contrast, no inhibitory effect is observed when platelets are exposed to thromboxane A2 (TxA2) mimetic (U46619) or arachidonic acid. Moreover, there was no effect either on blood coagulation or A, B and O washed human erythrocytes agglutination. Furthermore, flow cytometric analysis revealed that fluoro-isothiocyanate (FITC)-labelled lebecetin bound to human formalin fixed platelets in a saturable and concentration manner and this binding was specifically prevented by anti-glycoprotein Ib (GPIb) mAb. These observations suggest that lebecetin is a C-type lectin-like protein that selectively binds to platelet GPIb.     

Chemodiversity of Volatile Oils in Thapsia garganica L. (Apiaceae)

The chemical composition of the volatile oils obtained from the roots, leaves, flowers, and stems of Thapsia garganica of Tunisian origin was investigated by GC‐FID and GC/MS analyses. Sesquiterpene hydrocarbons and oxygenated monoterpenes were predominant in the oils of all plant parts. Bicyclogermacrene (21.59–35.09%) was the main component in the former compound class, whereas geranial (3.31–14.84%) and linalool (0.81–10.9%) were the most prominent ones in the latter compound class. Principal‐component (PCA) and hierarchical‐cluster (HCA) analyses revealed some common constituents, but also significant variability amongst the oils of the different plant parts. This organ‐specific oil composition was discussed in relation to their biological and ecological functions. For the evaluation of the intraspecific chemical variability in T. garganica, the composition of the flower volatile oils from four wild populations was investigated. Bicyclogermacrene, linalool, and geranial were predominant in the oils of three populations, whereas epicubenol, β‐sesquiphellandrene, and cadina‐1,4‐diene were the most prominent components of the oil of one population. PCA and HCA allowed the separation of the flower oils into three distinct groups, however, no relationship was found between the volatile‐oil composition and the geographical distribution and pedoclimatic conditions of the studied populations.     

Effects of zinc pre-treatment on blood glutathione,serum zinc and kidney histological organisation in male rats exposed to cadmium

The effects of sub-chronic exposure to cadmium (Cd) on the blood glutathione, serum zinc and on the kidney histological organisation in rats as well as the possible protective role of zinc (Zn) are the object of this study. For this purpose, 60 male Wistar rats (8 weeks old) were divided into three groups: the first group was exposed to Cd in the form of CdCl₂, administered in five doses (each of 0.4 mg Cd/kg b.w.) on days 5, 10, 15, 20 and 25, giving a total dose of 2 mg Cd/kg b.w., i.p.; the second group was simultaneously exposed to Zn and Cd with the same timeline and the same doses of Cd as the first group but with, in addition, injections of Zn in the form of ZnCl₂, administered in doses of 0.8 mg Zn/kg b.w., giving a total dose of 4 mg Zn/kg b w, i.p.; a control group received 0.5 mL of physiological saline in an identical manner. Intoxication with Cd was followed by a significant decrease in blood glutathione, increase in oxidized glutathione as well as histological damage in kidneys. Pre-treatment with Zn exhibited a protective role against Cd toxicity with a significant decrease in serum zinc content. This fact may be explained by an excessive use of zinc in metallothionein synthesis as a cadmium detoxification agent.