An initial study of fallow periods on the nematode community in the Soudanese-Sahelian zone of Senegal

Les observations ont été réalisées sur des jachères naturelles, sur sols ferrugineux peu profonds, dans la région de Nioro du Rip au Sud du Sénégal. Sur l'ensemble du site, 12 espèces de nématodes phytoparasites ont été identifiées. Dans les jachères anthropisées, l'effectif du peuplement ainsi que le nombre d'espèces observées diminuent lorsque l'âge de la jachère augmente de 1 à 17 ans. La mise en défens pendant 5 ans d'une jachère de 17 ans modifie ces tendances : le peuplement diminue moins vite et le nombre d'espèces est plus élevé que dans les zones anthropisées. Au plan qualitatif, seuls #Helicotylenchus dihystera et #Tylenchorhynchus gladiolatus se développent quelle que soit la situation de la jachère. Parmi les autres espèces, #Xiphinema parasetariae est plus particulièrement présent sur les jachères âgées et inversement pour #Scutellonema cavenessi. La mise en défens fait pratiquement disparaître cette espèce considérée comme très dangereuse pour les cultures de cette région. Le peuplement de nématodes saprophages reste pratiquement stable sur les jachères anthropisées. Il augmente sur la jachère en défens, notamment à proximité des ligneux. Parmi les espèces végétales, #Andropogon pseudapricus, contrairement à #Pennisetum pedicellatum, est généralement associé à des populations importantes de nématodes. (Résumé d'auteur

Size and the Not-So-Single Sex: Disentangling the Effects of Size and Budget on Sex Allocation in Hermaphrodites

Sex allocation theory explains how size-related variations in male and female fitness may favor the evolution of size-dependent sex allocation in hermaphrodites. Although empirical studies show that sex allocation changes gradually with size in many species, theoretical studies tend to predict an abrupt sex reversal from one sex to the other, that is, single-sexed sequential hermaphrodites. We show that this discrepancy between data and theory collapses if one takes into account that size affects male and female fitness through distinct routes. Using the classification of budget (larger individuals spend a greater budget on reproduction) and direct (e.g., larger plants are taller and may disperse pollen more efficiently) effects of size suggested by Klinkhamer et al., we propose a simple general framework appropriately incorporating these two categories of size effects in male and female fitness expressions. Analytical and numerical results show that a gradual sex change is evolutionarily stable for a large set of parameter values. Sex reversal is selected only in the absence of budget effects of size. We provide further predictions on size-dependent sex allocation and assess the relative importance of budget and direct effect for creating different patterns

Dextran sulfate enhances the level of an oxidative DNA damage biomarker, 8-oxo-7,8-dihydro-2'-deoxyguanosine, in rat colonic mucosa.

International audienceDextran sodium sulfate (DSS) given in drinking water can induce colonic inflammation and produce colorectal tumors in rodents, although it is not directly genotoxic. The hypothesis that DSS can produce free radicals and induce oxidative DNA damage in colonic mucosa has been tested. In rats fed for 2 days with water containing 3% and 6% DSS, colonic inflammation manifestations were recorded and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), a major biomarker of oxidative DNA damage, was assayed in colonic mucosa. As compared with control rats given pure water, inflammatory manifestations were seen in rats given DSS. At the same time, 8-oxodGuo levels in colonic mucosa were doubled (P < 0.001). These results suggest that formation of oxidative DNA damage in colonic mucosa depends on inflammation and maybe on the production of reactive oxygen species. This study shows that DSS can induce oxidative DNA damage within only 2 days, which could explain in part its carcinogenic properties

Cloning, Expression and Purification of an Acetoacetyl CoA Thiolase from Sunflower Cotyledon

Thiolase I and II coexist as part of the glyoxysomal β-oxidation system in sunflower (Helianthus annuus L.) cotyledons, the only system shown to have both forms. The importance of thiolases can be underscored not only by their ubiquity, but also by their involvement in a wide variety of processes in plants, animals and bacteria. Here we describe the cloning, expression and purification of acetoacetyl CoA thiolase (AACT) in enzymatically active form. Use of the extensive amount of sequence information from the databases facilitated the efficient generation of the gene-specific primers used in the RACE protocols. The recombinant AACT (1233 bp) shares 75% similarity with other plant AACTs. Comparison of specific activity of this recombinant AACT to a previously reported enzyme purified from primary sunflower cotyledon tissue was very similar (263 nkat/mg protein vs 220 nkat/mg protein, respectively). Combining the most pure fractions from the affinity column, the enzyme was purified 88-fold with a 55% yield of the enzymatically active, 47 kDa AACT

Getting to the Left of SHARP: Lessons Learned from West Point\u27s Efforts to Combat Sexual Harassment and Assault

View the Executive SummaryOn July 26, 1948, President Harry Truman signed Executive Order 9981, ending the practice of segregating the military services by race. That same year, the Army allowed women to join the services on an equal basis with men. Both of these steps preceded the larger societal changes that allowed fully equal treatment of all types of American citizens in military service. Just over 2 years ago, Congress repealed the Don’t Ask, Don’t Tell policy, allowing for gays and lesbians to openly take their place in the military. Our procedures and policies for successful gender integration have grown and evolved. The authors share five principles for leaders and commanders on the prevention of sexual harassment and assault, as well as associated “Tips” for implementation: (1) Leaders identify and break chains of circumstance; (2) Education is preferable to litigation; (3) What’s electronic is public; (4) Don’t ignore pornography; and, (5) Unit climate is the commander’s responsibility. These principles and their associated tips are not panaceas, and these recommendations are submitted for discussion and feedback.https://press.armywarcollege.edu/monographs/1468/thumbnail.jp

Protein Block Expert (PBE): a web-based protein structure analysis server using a structural alphabet

Encoding protein 3D structures into 1D string using short structural prototypes or structural alphabets opens a new front for structure comparison and analysis. Using the well-documented 16 motifs of Protein Blocks (PBs) as structural alphabet, we have developed a methodology to compare protein structures that are encoded as sequences of PBs by aligning them using dynamic programming which uses a substitution matrix for PBs. This methodology is implemented in the applications available in Protein Block Expert (PBE) server. PBE addresses common issues in the field of protein structure analysis such as comparison of proteins structures and identification of protein structures in structural databanks that resemble a given structure. PBE-T provides facility to transform any PDB file into sequences of PBs. PBE-ALIGNc performs comparison of two protein structures based on the alignment of their corresponding PB sequences. PBE-ALIGNm is a facility for mining SCOP database for similar structures based on the alignment of PBs. Besides, PBE provides an interface to a database (PBE-SAdb) of preprocessed PB sequences from SCOP culled at 95% and of all-against-all pairwise PB alignments at family and superfamily levels. PBE server is freely available at