The effects of protection on steppic vegetation in the Mediterranean arid zone of Southern Tunisia

Plant Ecology - The results of observations and measurements on five units of steppic vegetation in the mediterranean arid zone of S. Tunisia are presented in this paper. These units were totally...     

Characterization of six novel mutations in the CYBB gene leading to different sub-types of X-linked chronic granulomatous disease

Chronic granulomatous disease is an inherited disorder in which phagocytes lack a functional NADPH oxidase and so cannot generate superoxide anions (O₂^–). The most common form is caused by mutations in CYBB encoding gp91 phox, the heavy chain of flavocytochrome b₅₅₈ (XCGD). We investigated 11 male patients and their families suspected of suffering from X-linked CGD. These XCGD patients were classified as having different variants (X91⁰, X91^– or X91⁺) according to their cytochrome b₅₅₈ expression and NADPH oxidase activity. Nine patients had X91⁰ CGD, one had X91^– CGD and one had X91⁺ CGD. Six mutations in CYBB were novel. Of the four new X91⁰ CGD cases, three were point mutations: G65A in exon 2, G387T in exon 5 and G970T in exon 9, leading to premature stop codons at positions Try18, Try125 and Glu320, respectively, in gp91 phox. One case of X91⁰ CGD originated from a new 1005G deletion detected in exon 9. Surprisingly, four nonsense mutations in exon 5 led to the generation of two mRNAs, one with a normal size containing the mutation and the other in which exon 5 had been spliced. A novel X91^– CGD case with low gp91 phox expression was diagnosed. It was caused by an 11-bp deletion in the linking region between exon 12 and intron 12, activating a new cryptic site. Finally, a new X91⁺ CGD case was detected, characterized by a missense mutation Leu505Arg in the potential NADPH-binding site of gp91 phox. No clear correlation between the severity of the clinical symptoms and the sub-type of XCGD could be established.     

Le ganglion sentinelle dans les cancers de la cavité orale : impact clinique et apport de l’imagerie hybride

ObjectivesWe report a prospective evaluation of the sentinel lymph node identification and biopsy in oral cavity cancer in order to assess the additional value of the single photon emission computed tomography-computed tomography (SPECT-CT).Patients and methodsThirteen patients with T1 or T2 clinical N0 oral cavity cancer were prospectively included. They first underwent a lymphoscintigraphy with planar imaging. A SPECT-CT was performed secondly. Finally, excised sentinel lymph nodes were screened according to a specific histological processing.ResultsThe scintigraphic detection rate was 100%, both with planar and SPECT/CT imaging. Dynamic and early images were predictive of the lymph node drainage territory for 11 patients (85%). An impact of SPECT/CT in 83% of cases was achieved with additional quantitative information in 58% cases and qualitative information in 58% cases. A greater sensibility was also pointed out for level 1 sentinel lymph nodes, close to the injection site. Once, an occult metastasis was revealed by the histological analysis of the sentinel lymph nodes.ConclusionRadioisotopic sentinel lymph node technique for oral cavity cancers allowed determining neck node status for all patients. Ninety-two percent of them were spared from a radical neck dissection or radiotherapy. Preoperative detection of sentinel lymph node is optimised in most cases by hybrid imaging procedure. Anatomical data provided by hybrid imaging are useful for surgery.     

Citizen science in schools: Engaging students in research on urban habitat for pollinators

Citizen science can play an important role in school science education. Citizen science is particularly relevant to addressing current societal environmental sustainability challenges, as it engages the students directly with environmental science and gives students an understanding of the scientific process. In addition, it allows students to observe local representations of global challenges. Here, we report a citizen science programme designed to engage school‐age children in real‐world scientific research. The programme used standardized methods deployed across multiple schools through scientist–school partnerships to engage students with an important conservation problem: habitat for pollinator insects in urban environments. Citizen science programmes such as the programme presented here can be used to enhance scientific literacy and skills. Provided key challenges to maintain data quality are met, this approach is a powerful way to contribute valuable citizen science data for understudied, but ecologically important study systems, particularly in urban environments across broad geographical areas.     

Influence of 1-[(E)-2-(2-methyl-4-nitrophenyl)diaz-1-enyl]pyrrolidine-2-carboxylic acid and diphenyliodonium chloride on ruminal protein metabolism and ruminal microorganisms.

The effects of 1-[(E)-2-(2-methyl-4-nitrophenyl)diaz-1-enyl]pyrrolidine-2-carboxy lic acid (LY29) and diphenyliodonium chloride (DIC) on the degradation of protein to ammonia were determined in a mixed rumen microbial population taken from sheep on a grass hay-concentrate diet. Both compounds decreased NH3 production by inhibiting deamination of amino acids. LY29, but not DIC, inhibited growth of the high-activity ammonia-producing species, Clostridium aminophilum and Clostridium sticklandii.     

Development of an herbaceous cover in a Sudano-Sahelian savanna in North Cameroon in relation to available soil water

Dynamics of annual communities are studied in Sudano-Sahelian savannas of the north of the Cameroon. The vegetation composition of three types of soil (a vertisol, a degraded vertisol and a ferruginous soil) under two rainfall conditions is compared. The study supports the idea that intense fluctuations in water availability at the beginning of the rainy season determine which species germinate, grow and survive under conditions of water stress. However soil conditions can accentuate or reduce the influence of the rainfall fluctuations while the land use history of each station tends to buffer the variations of the overall pattern determining potential vegetation.     

Restoration and Rehabilitation of Degraded Ecosystems in Arid and Semi-Arid Lands. II. Case Studies in Southern Tunisia, Central Chile and Northern Cameroon

A model of ecosystem degradation and three possible responses to it—restoration, rehabilitation, and real-location—is applied to ongoing projects in the arid mediterranean region of southern Tunisia, the subhumid mediterranean region of central Chile, and the semiarid tropical savannas of northern Cameroon. We compare both nonhuman and human determinants of ecosystem degradation processes in these contrasted regions, as well as interventions being tested in each. A number of quantifiable “vital ecosystem attributes” are used to evaluate the effects of ecosystem degradation and the experimental responses of rehabilitation on vegetation, soils and plant-soil-water relations. We argue that attempts to rehabilitate former ecosystem structure and functioning, both above- and below ground, are the best way to conserve biodiversity and insure sustainable long-term productivity in ecosystems subjected to continuous use by people in arid and semi-arid lands of “the South.” The success of such efforts, however, depends not only on elucidating the predisturbance (or slightly disturbed) structure and function of the consciously selected “ecosystem of reference,” but also on understanding and working with the socioeconomic, technical, cultural, and historical factors that caused the degradation in the first place.