Kenaf (Hibiscus cannabinus L.) is a valuable fiber and medicinal plant from the Malvaceae family. It is an alternative crop that may be a feasible source of cellulose which is economically viable and ...ecologically friendly. This plant is cultivated for its fiber although its leaves and seeds have also been used in traditional medicine in India and Africa for the treatment of various disease conditions. Kenaf fibers are commonly used for paper pulp and cordage, but it is also a promising lignocellulosic feedstock for bioenergy production. The kenaf seed oil can be used for cooking and in different industrial applications. The present paper is an overview on its ethnobotanical and phytochemical properties reported in the literature that we have investigated and its great potential as a valuable multipurpose crop due to numerous uses.
According to the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC), global climate change is now unequivocal. Tunisia, like many other countries, has been affected by ...climate changes, including rising temperatures, intense heatwaves, and altered precipitation regimes. Tunisia's mean annual temperatures has risen about +1.4 °C in the twentieth century, with the most rapid warming taking place since the 1970s. Drought represents a primary contributing factor to tree decline and dieback. Long‐term drought can result in reduced growth and health of trees, thereby increasing their susceptibility to insect pests and pathogens. Reported increases in tree mortality point toward accelerating global forest vulnerability under hotter temperatures and longer, more intense droughts. In order to assess the effect of these climate changes on the current state of forest ecosystems in Tunisia and their evolution, an investigative study was required. Here, we review the current state of knowledge on the effects of climate change on sclerophyllous and semi‐deciduous forest ecosystems in Tunisia. Natural disturbance during recent years, as well as the adaptability and resilience of some forest species to climate change, were surveyed. The Standardized Precipitation Evapotranspiration Index (SPEI) is a multi‐scalar drought index based on climate data that has been used to analyse drought variability. The SPEI time scale analysis showed a negative trend over the 1955–2021 period in Tunisian forest regions. In 2021, Tunisia lost 280 km2 of tree cover to fires, which is equivalent to 26% of the total lost area between 2008 and 2021. Changing climate conditions have also affected phenological parameters, with an advance in the start of the green season (SOS) of 9.4 days, a delay at the end of the green season (EOS) of 5 days, with a consequent extended duration of the green season (LOS) by an average of 14.2 days. All of these alarming findings invite us to seek adaptation strategies for forest ecosystems. Adapting forests to climate change is therefore a challenge for scientists as well as policymakers and managers.
Emergent vulnerability to climate‐driven disturbances in Mediterranean forests: advancing the understanding resilience and adaptive capacity.
Pistacia lentiscus L. is known in some Tunisian forest area by its fixed oil used in traditional medicine as an antiseptic product. This investigation is the first to study the antimicrobial activity ...of P.lentiscus edible oil and its phenolic extract. Oil was extracted from fruits harvested from six provenances located in Tunisia. The antimicrobial activity was tested using disc diffusion assay and the broth dilution method. Kbouch and Sidi Zid oils were most efficient (p < 0.003) against, respectively, Staphylococcus aureus and Aspergillus niger with an inhibition zone of 9.33 mm. The phenolic extract had the largest spectrum of sensitive microorganisms. The minimum inhibitory concentration and minimum bactericidal concentration results showed that all strains were inhibited by both oil and extract.
Nineteen Tunisian carob populations from different sites were studied to assess their genetic variation based on pods and kernels measures. The mean of the main descriptive morphological values of ...pods were weight (16.39
g), length (168.9
mm), width (20.5
mm), lateral thickness (8.3
mm), central thickness (5.8
mm), number of viable kernels (12.26), number of aborted kernels (1.38), kernels weight (0.2
g), kernel length (9.1
mm), kernel width (6.9
mm), kernel thickness (4.1
mm) and kernel yield (17.2%). Most of the parameters measured showed significant differences (
P
<
0.05 to
P
<
0.001) that indicates a high genetic diversity; type and geographical origin of trees being taken as the source of variation.
The relationship among these characters was analysed by principal component analysis (PCA) resulting in the separation of these populations classed in three grouped and three ungrouped populations.
Eucalyptus is the second major wood species used for Tunisian reforestation since 1957, and they are found around the country in several arboretums. Eucalyptus may be an interesting raw material to ...the Tunisian wood industry. The main obstacle to its industrial exploitation is its natural propensity to incur internal checking, collapse and a high transverse shrinkage during industrial drying process. This study focused on the physical and mechanical properties of reforested Eucalytus saligna and Eucalyptus camaldulensis from the north west of Tunisia. Moisture content, densities, shrinkages and mechanical properties were determined. Then, the impact of pre-steaming on the physical properties of modified wood was investigated. The results showed that both Eucalyptus possess low dimensional stability and mechanical properties compared to other Eucalyptus species from Tunisia, Morocco, Australia and Brazil. These wood characteristics were mainly due to their low density and sensitivity to collapse reactions, occurred during drying. Pre-steaming process reduced Eucalypts wood moisture content, changing the wood permeability and resulting in a residual collapse recovery and a decrease in wood shrinkage. Pre-steaming treated E. camaldulensis and E. saligna wood could be valuable as furniture and/or structural material without being submitted to moisture content variation.
The most interesting factors associated with seed and cone production of Aleppo pine were largely reviewed to identify broad patterns and potential effectiveness of reforestation efforts and ...planning. Aleppo pine cone production and seed yields are relatively variable, with differences between spatial and temporal influences. These differences are considered, mainly between (i) year, (ii) stand characteristics and (iii) individual tree measurements. Annual variability among populations was recorded for cone production per tree, based on influencing factors such as genetic characteristics, wetness, nutrient availability, insect pests and disease. In addition, some factors may affect Aleppo pine tree growth directly but may be affecting seed and cone production indirectly. Therefore, reduced stand density results in less competition among Aleppo pine trees and accompanying understory flora, which subsequently increases the stem diameter and other tree dimensions, including seed production. This review suggests that reforestation planning, particularly thinning, will result in improved tree morphology that will increase Aleppo pine seed and cone crops. Wildfire intensity and stand conditions such as light and soil nutrient status are also examined.
Abstract
Background
Despite highly effective HIV preexposure prophylaxis (PrEP) options, no options provide on-demand, nonsystemic, behaviorally congruent PrEP that many desire. A tenofovir-medicated ...rectal douche before receptive anal intercourse may provide this option.
Methods
Three tenofovir rectal douches—220 mg iso-osmolar product A, 660 mg iso-osmolar product B, and 660 mg hypo-osmolar product C—were studied in 21 HIV-negative men who have sex with men. We sampled blood and colorectal tissue to assess safety, acceptability, pharmacokinetics, and pharmacodynamics.
Results
The douches had high acceptability without toxicity. Median plasma tenofovir peak concentrations for all products were several-fold below trough concentrations associated with oral tenofovir disoproxil fumarate (TDF). Median colon tissue mucosal mononuclear cell (MMC) tenofovir-diphosphate concentrations exceeded target concentrations from 1 hour through 3 to 7 days after dosing. For 6–7 days after a single product C dose, MMC tenofovir-diphosphate exceeded concentrations expected with steady-state oral TDF 300 mg on-demand 2-1-1 dosing. Compared to predrug baseline, HIV replication after ex vivo colon tissue HIV challenge demonstrated a concentration-response relationship with 1.9 log10 maximal effect.
Conclusions
All 3 tenofovir douches achieved tissue tenofovir-diphosphate concentrations and colorectal antiviral effect exceeding oral TDF and with lower systemic tenofovir. Tenofovir douches may provide a single-dose, on-demand, behaviorally congruent PrEP option, and warrant continued development.
Clinical Trials Registration
. NCT02750540.
Tenofovir formulated as a rectal douche offers the potential for a single-dose, on-demand, acceptable, and behaviorally congruent option for HIV preexposure prophylaxis supported by colorectal tissue tenofovir diphosphate and antiviral effect exceeding similar measures associated with oral tenofovir disoproxil fumarate.
In this investigation, we aim to study, for the first time, the effect of the growing area on tocopherols, carotenoids and fatty acid content of Pistacia lentiscus fixed oil. Fruits were harvested ...from eight different sites located in the north and the centre of Tunisia. Tocopherols, carotenoids and fatty acid content of the fixed oils were determined. The highest carotenoid content was exhibited by Feija oil (10.57 mg/kg of oil). Oueslatia and Tabarka oils displayed the highest α-tocopherol content (96.79 and 92.79 mg/kg of oil, respectively). Three major fatty acids were determined: oleic, palmitic and linoleic acids. Oleic acid was the main fatty acid presenting more than 50% of the total fatty acid content. Kebouche oil presented the highest oleic acid content (55.66%). All these results highlight the richness of carotenoids, tocopherols and unsaturated fatty acids in P. lentiscus seed oil and underscore the nutritional value of this natural product.
Acer monspessulanum (maple) is an endemic endangered tree with a wide but fragmented distribution in the Mediterranean mountains. The persistence of its small populations depends often on few adults, ...which makes it is highly vulnerable to limiting recruitment factors. In this paper, we examined the regeneration status of this maple in three populations through its geographical distribution in the mountain range of the Tunisian dorsal (Jbel Srerej national park and sacred site). Morphological parameters, genetic variability, and diversity were analyzed as species viability indicators. The ecological site of maple was studied based on the soil texture and structure under the population, additionally to the role of shrubs as nurse plants in maple regeneration dynamic. Here, the maple population in Tunisia was investigated for the first time. The results show that Acer monspessulanum population has a variation terms of height, stem diameter and crown diameter, it also shows that there is a good natural regeneration. Analysis of the soil's physicochemical parameters showed that the species grows on sandy loam and clay loam soil, shallow and slightly alkaline pH. This study contributes to better characterization of the Tunisian maple population and its ecological niche from the standpoint of soil and vegetation.
▶ Currently there are no reports describing methods for the in vitro propagation of kenaf. Hence, development of suitable regeneration methods would be interesting. The purpose of this study was to ...develop an efficient and suitable protocol for micropropagation of H. cannabinus plants through multiple buds growing from nodal and apical explants using MS medium free from growth regulators and without a rooting step.
The present study report a protocol for the efficient in vitro propagation of kenaf (Hibiscus cannabinus L., an industrial crop having high cellulosic fiber content) on hormone free MS medium using the shoot apex and nodal explants. Shoot tips and nodes were isolated from 15 days old seedlings cultivated on MS medium. Different combinations and concentrations of auxin/cytokinin were used and added to the MS medium to assess the shoot and root induction of theses explants. Several subcultures were drived in order to enhance the multiplication rate. Healthy and well developed in vitro propagated shoots were transferred for acclimatization under greenhouse conditions in pots filled with different substrates (sand+compost or perlite). Our results showed that shoots could elongate and root within 4–6 weeks on MS basal medium without any callus formation. However, addition of growth regulators to the MS medium leaded to a decrease in shoot and root induction rates. Indeed, the highest shoot regeneration frequency (90.5%) was obtained on MS control medium. Elongated shoots were transferred onto the same hormone free MS medium using five subcultures where the multiplication rate reached the highest value (3.66) at the fifth and last step. The in vitro rooted plantlets were acclimatized in greenhouse and successfully transplanted to natural conditions with 70% survival.
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