Plants in traditional home gardens: richness,composition, conservation and implications for native biodiversity in Benin

Home gardens have received increasing attention and have been insistently presented as hotspots for agro-biodiversity over the last decades. However, apart from their exceptional high plant species diversity, there is little quantitative evidence of the effectiveness of plant species conservation in home gardens. This study examined this issue by assessing (i) the size and membership of garden flora and the contribution to the maintenance of the national flora, (ii) how home garden flora connects to the larger ecosystem it belongs to and (iii) the conservation status of plant species at the home garden level. 360 home gardens distributed in three agro-ecological zones and nine phyto-geographical districts in Benin were visited and inventoried. Diversity parameters at different taxonomic levels were calculated. Species accumulation and spatial occupancy, multivariate methods and rarity index were also used for data analysis. Findings showed that the 360 studied home gardens hosted up to 14.21% of plant species and 44.32% of plant families of the national flora. Home garden flora was constantly dominated by exotic plant species but strongly connected to their surrounding ecosystems, being composed of at least 60% of plant species from their phyto-geographical districts. Finally, home garden plant species were mostly rare and threatened at the home garden level. In this study, we acknowledge the contribution of home gardens to the maintenance of plant species diversity at regional and global levels than local level. Based on the observed prevalence of exotic species, HG effectiveness in sustainably conserving native plant species biodiversity remains questionable.     

Mitochondria in cardiomyocyte Ca signaling

Ca²⁺ signaling is of vital importance to cardiac cell function and plays an important role in heart failure. It is based on sarcolemmal, sarcoplasmic reticulum and mitochondrial Ca²⁺ cycling. While the first two are well characterized, the latter remains unclear, controversial and technically challenging.In mammalian cardiac myocytes, Ca²⁺ influx through L-type calcium channels in the sarcolemmal membrane triggers Ca²⁺ release from the nearby junctional sarcoplasmic reticulum to produce Ca²⁺ sparks. When this triggering is synchronized by the cardiac action potential, a global [Ca²⁺]_i transient arises from coordinated Ca²⁺ release events. The ends of intermyofibrillar mitochondria are located within 20 nm of the junctional sarcoplasmic reticulum and thereby experience a high local [Ca²⁺] during the Ca²⁺ release process. Both local and global Ca²⁺ signals may thus influence calcium signaling in mitochondria and, reciprocally, mitochondria may contribute to the local control of calcium signaling. In addition to the intermyofibrillar mitochondria, morphologically distinct mitochondria are also located in the perinuclear and subsarcolemmal regions of the cardiomyocyte and thus experience a different local [Ca²⁺].Here we review the literature in regard to several issues of broad interest: (1) the ultrastructural basis for mitochondrion – sarcoplasmic reticulum cross-signaling; (2) mechanisms of sarcoplasmic reticulum signaling; (3) mitochondrial calcium signaling; and (4) the possible interplay of calcium signaling between the sarcoplasmic reticulum and adjacent mitochondria.Finally, this review discusses experimental findings and mathematical models of cardiac calcium signaling between the sarcoplasmic reticulum and mitochondria, identifies weaknesses in these models, and suggests strategies and approaches for future investigations.     

Prevalence and Risk Factors of Lassa Seropositivity in Inhabitants of the Forest Region of Guinea: A Cross-Sectional Study

Background

Lassa fever is a viral hemorrhagic fever endemic in West Africa. The reservoir host of the virus is a multimammate rat, Mastomys natalensis. Prevalence estimates of Lassa virus antibodies in humans vary greatly between studies, and the main modes of transmission of the virus from rodents to humans remain unclear. We aimed to (i) estimate the prevalence of Lassa virus–specific IgG antibodies (LV IgG) in the human population of a rural area of Guinea, and (ii) identify risk factors for positive LV IgG.

Methods and Findings

A population-based cross-sectional study design was used. In April 2000, all individuals one year of age and older living in three prefectures located in the tropical secondary forest area of Guinea (Gueckedou, Lola and Yomou) were sampled using two-stage cluster sampling. For each individual identified by the sampling procedure and who agreed to participate, a standardized questionnaire was completed to collect data on personal exposure to potential risk factors for Lassa fever (mainly contact with rodents), and a blood sample was tested for LV IgG. A multiple logistic regression model was used to determine risk factors for positive LV IgG. A total of 1424 subjects were interviewed and 977 sera were tested. Prevalence of positive LV Ig was of 12.9% [10.8%–15.0%] and 10.0% [8.1%–11.9%] in rural and urban areas, respectively. Two risk factors of positive LV IgG were identified: to have, in the past twelve months, undergone an injection (odds ratio [OR] = 1.8 [1.1–3.1]), or lived with someone displaying a haemorrhage (OR = 1.7 [1.1–2.9]). No factors related to contacts with rats and/or mice remained statistically significant in the multivariate analysis.

Conclusions

Our study underlines the potential importance of person-to-person transmission of Lassa fever, via close contact in the same household or nosocomial exposure.     

Dynamics of calcium sparks and calcium leak in the heart

We present what we believe to be a new mathematical model of Ca²⁺ leak from the sarcoplasmic reticulum (SR) in the heart. To our knowledge, it is the first to incorporate a realistic number of Ca²⁺-release units, each containing a cluster of stochastically gating Ca²⁺ channels (RyRs), whose biophysical properties (e.g., Ca²⁺ sensitivity and allosteric interactions) are informed by the latest molecular investigations. This realistic model allows for the detailed characterization of RyR Ca²⁺-release properties, and shows how this balances reuptake by the SR Ca²⁺ pump. Simulations reveal that SR Ca²⁺ leak consists of brief but frequent single RyR openings (∼3000 cell⁻¹ s⁻¹) that are likely to be experimentally undetectable, and are, therefore, “invisible”. We also observe that these single RyR openings can recruit additional RyRs to open, due to elevated local (Ca²⁺), and occasionally lead to the generation of Ca²⁺ sparks (∼130 cell⁻¹ s⁻¹). Furthermore, this physiological formulation of “invisible” leak allows for the removal of the ad hoc, non-RyR mediated Ca²⁺ leak terms present in prior models. Finally, our model shows how Ca²⁺ sparks can be robustly triggered and terminated under both normal and pathological conditions. Together, these discoveries profoundly influence how we interpret and understand diverse experimental and clinical results from both normal and diseased hearts.     

Reconstructive surgery for giant penoscrotal elephantiasis: about one case

Elephantiasis of the external genitalia is characterized by lymphedema and thickening of the subcutaneous tissues. This gives the skin an appearance similar to a pachyderm skin. This pathology is invalidating for the patient. Reconstructive surgery is often the only way to restaure aesthetic and functional aspects of the external genitalia. We aim to report a 52 year man with huge penoscrotal elephantiasis who underwent excision and penoscrotal reconstruction at the department of Urology, Yalgado Ouedraogo Teaching Hospital at Ouagadougou.     

Action of the antitumor and antispermatogenic agent lonidamine on electron transport in ehrlich ascites tumor mitochondria

The effect of lonidamine, an antispermatogenic and antitumor drug, on the oxygen consumption, ATPase activity, and redox state of the electron carriers of Ehrlich ascites tumor mitochondria has been studied. Lonidamine inhibits ADP- and uncoupler-stimulated respiration on various NAD- and FAD-linked substrates, but does not affect state 4 respiration. Experiments to determine its site of action showed that lonidamine does not significantly inhibit electron flow through cytochrome oxidase. Electron flow through site 2, the ubiquinone-cytochrome b-cytochrome c₁ complex, also was unaffected by lonidamine, which failed to inhibit the oxidation of duroquinol. Moreover, inhibition of electron flow through site 2 was also excluded because of the inability of the N,N,N′,N′-tetramethyl-p-phenylenediamine bypass to relieve the lonidamine inhibition of the oxidation of pyruvate + malate. The F₀F₁ATPase activity and vectorial H⁺ ejection are also unaffected by lonidamine. The inhibition of succinate oxidation by lonidamine was found to take place at a point between succinate and iron-sulfur center S3. Spectroscopic experiments demonstrated that lonidamine inhibits the reduction of mitochondrial NAD⁺ by pyruvate + malate and other NAD-linked substrates in the transition from state 1 to state 4. However, lonidamine does not inhibit reduction of added NAD⁺ by submitochondrial vesicles or by soluble purified NAD-linked dehydrogenases. These observations, together with other evidence, suggest that electron transport in tumor mitochondria is inhibited by lonidamine at the dehydrogenase-coenzyme level, particularly when the electron carriers are in a relatively oxidized state and/or when the inner membrane-matrix compartment is in the condensed state. The action of lonidamine in several respects resembles the selective inhibition of electron transport in tumor cells produced by cytotoxic macrophages.     

Species richness,cultural importance,and prioritization of wild spices for conservation in the Sudano-Guinean zone of Benin (West Africa)

Background

Spices have always been used for their flavor-enhancement characteristics and for their medicinal properties. In Benin, scientific research on spices is scarce, despite their importance in the local population’s daily needs. This study investigated the diversity of wild spices and documented the associated traditional knowledge that can be used for their valuation, domestication, and sustainable management in the Sudano-Guinean Zone of Benin.

Methods

Data were collected during field expeditions using semi-structured interviews in ten localities across the three phytodistricts of the zone. Species richness and Shannon’s diversity index were estimated using species accumulation curves. Use report (UR), cultural importance, use value (UV) index, and informant consensus factor (F_ic) were used to assess traditional knowledge on wild species, their local importance, and informants’ agreement among sociolinguistic groups. Priority wild spices were finally identified using an approach combining eight criteria (native status, economic value, ethnobotanical value, global distribution, national distribution, in-situ and ex-situ conservation status, legislation, and threats assessment) in four prioritization methods (point scoring procedure, point scoring procedure with weighting, compound ranking system, and binomial ranking system).

Results

A total of 14 species, belonging to 12 genera and 9 families, were inventoried. The most prominent families were Zingiberaceae (21.43%), Annonaceae (21.43%), and Rutaceae (14.29%). More than 200 specific uses were reported, with the Tchabè people holding the greatest level of knowledge (70 uses; UR?=?5.70?±?0.33). The culturally most important spices differed among sociolinguistic groups. Most of the informants agree on the use of the species among (F_ic = 0.72–0.98) and across the considered use categories (F_ic = 0.88–0.99). The highest UV were registered for Aframomum alboviolaceum (UV?=?0.93), Lippia multiflora (UV?=?0.76), and Aframomum angustifolium (UV?=?0.18). Overall, people perceived wild spices as declining due to agriculture, grazing, and drought. Five species, A. alboviolaceum, L. multiflora, Monodora tenuifolia, Xylopia aethiopica, and Z. zanthoxyloides, were the most prioritized for conservation.

Conclusions

This study provides information relevant for the implementation of conservation and domestication actions of wild spices in Benin. Priority species could be integrated into traditional agroforestry systems (e.g., home gardens). However, for this to be effective, further research should be undertaken on morphological and genetic diversity and propagation methods of priority wild spices.

     

Association of anthracyclines and synthetic hexanucleotides. Structural factors influencing sequence specificity

The equilibrium and kinetic aspects of the interaction between four anthracyclines and two synthetic self-complementary hexanucleotides was investigated by fluorescence detection. Two of the studied anthracyclines are widely used antitumor drugs: doxorubicin (1, formerly adriamycin) and daunorubicin (2, formerly daunomycin). The other two, 9-deoxydoxorubicin (3) and 3'-deamino-3'-hydroxy-4'-epidoxorubicin (4), are doxorubicin analogues with modifications of the chemical groups that have been proposed as responsible for sequence specificity (Chen, K.-X., Gresh, N. and Pullman, B. (1985). J. Biomol. Struct. Dyn. 3, 445-466). One of the oligonucleotides, d(CGTACG), is identical to that used in the high resolution x-ray structure determination of the daunorubicin intercalative complex (Wang, A. H.-J., Ughetto, G., Quigley, G. J. & Rich, A. (1987). Biochemistry 26, 1152-1163). Binding to this hexanucleotide is compared with intercalation into the d(CGCGCG) duplex, revealing sequence preferences of the four anthracyclines. Taking into account the anthracycline aggregation and the dissociation of the hexanucleotide double standard form, results can be interpreted with a model that assumes complete fluorescence quenching at intercalative sites containing the CG base pair, and a large residual fluorescence after intercalation within the TpA fragment. All four anthracyclines show preferential intercalation at sites near the ends of both hexanucleotide duplexes, partly as a result of positive cooperativity in the formation of di-intercalated species at these sites. Within the limits of experimental error, complete site specificity for the CpG fragment is found in the intercalation of 1 and 2 into d(CGTACG) duplex, whereas analogues 3 and 4 give increasing evidence of intercalation at other sites including the fluorescence-preserving TpA fragment. Site specificity is less pronounced in the association with d(CGCGCG), when cooperativity is taken into account. Kinetic data corroborate the results of equilibrium studies and are interpreted with a mechanism that includes formation of an intermediate bound species followed by drug redistribution to preferential sites. Finally, from a comparison of pertinent site binding constants, approximate free energy contributions to sequence specific DNA interaction, due to C9-OH on the aglycone and -NH3+ on daunosamine, are estimated not to exceed 2 kcal/mol.     

Le rôle de l’église et de la morale chrétienne sur le contrôle des naissances dès l’Antiquité à nos jours

This article discusses the role of the Church in birth control from Antiquity to the present day.