The Use of a Predictive Habitat Model and a Fuzzy Logic Approach for Marine Management and Planning

Bottom trawl survey data are commonly used as a sampling technique to assess the spatial distribution of commercial species. However, this sampling technique does not always correctly detect a species even when it is present, and this can create significant limitations when fitting species distribution models. In this study, we aim to test the relevance of a mixed methodological approach that combines presence-only and presence-absence distribution models. We illustrate this approach using bottom trawl survey data to model the spatial distributions of 27 commercially targeted marine species. We use an environmentally- and geographically-weighted method to simulate pseudo-absence data. The species distributions are modelled using regression kriging, a technique that explicitly incorporates spatial dependence into predictions. Model outputs are then used to identify areas that met the conservation targets for the deployment of artificial anti-trawling reefs. To achieve this, we propose the use of a fuzzy logic framework that accounts for the uncertainty associated with different model predictions. For each species, the predictive accuracy of the model is classified as ‘high’. A better result is observed when a large number of occurrences are used to develop the model. The map resulting from the fuzzy overlay shows that three main areas have a high level of agreement with the conservation criteria. These results align with expert opinion, confirming the relevance of the proposed methodology in this study.     

Reproduction characteristics,survival rate and sex-ratio of four brine shrimp Artemia salina (Linnaeus, 1758) populations from Tunisia cultured under laboratory conditions

Artemia has a remarkable genetic variability that can be expressed in various phenotypic characteristics, such as morphometry, growth rate, reproductive isolation or molecular composition. This study presents reproduction characteristics, survival rate and sex-ratio of four Artemia salina populations from Tunisia cultured under standard conditions. Results show that both low (17.8% and 30.6% in Megrine saltwork and Sabkhet Sijoumi, respectively) and high (83.9% for Sahline saltwork) values were recorded for the percentage of total oviparous offspring. The offspring per brood varied from 70.3?±?41.9 (Megrine saltwork) to 73.6?±?51.4 (Sabkhet El Adhibet). Broods per female varied between 3.1?±?0.9 (Sahline saltwork) and 4.5?±?1.2 (Megrine saltwork), and time between broods ranged from 5.7?±?1.1 to 6.5?±?2.2 days for Megrine and Sahline, respectively. Statistical analysis (one-way analysis of variance, Tukey's HSD test, p?<?0.05) revealed no significant differences between reproductive traits of the four studied populations except for mean of oviparous and oviviparous offspring per female (F?=?9.158, p?<?0.05), and brood per female (F?=?4.779, p?<?0.05). The survival rate of the four studied A. salina populations fluctuated between 31.4% and 64.5% for Megrine and Sahline saltwork, respectively. However, the sex-ratio showed that for Megrine saltwork and Sabkhet El Adhibet, males predominated with 1?:?0.90 and 1?:?0.97 (males?:?females), respectively. The comparison between our results and those reported of other Artemia populations showed that the offspring per brood of Tunisian Artemia are comparable to A. persimilis but different to A. salina from Abu Kammash (Libya) and A. urmiana (Urmia Lake, Iran), and that days between brood, are similar to A. salina from Abu Kammash, A. sinica and polyploid A. parthenogenetica, but different from A. persimilis and A. franciscana.     

Structural basis of siRNA recognition by TRBP double‐stranded RNA binding domains

The accurate cleavage of pre‐micro(mi)RNAs by Dicer and mi/siRNA guide strand selection are important steps in forming the RNA‐induced silencing complex (RISC). The role of Dicer binding partner TRBP in these processes remains poorly understood. Here, we solved the solution structure of the two N‐terminal dsRNA binding domains (dsRBDs) of TRBP in complex with a functionally asymmetric siRNA using NMR, EPR, and single‐molecule spectroscopy. We find that siRNA recognition by the dsRBDs is not sequence‐specific but rather depends on the RNA shape. The two dsRBDs can swap their binding sites, giving rise to two equally populated, pseudo‐symmetrical complexes, showing that TRBP is not a primary sensor of siRNA asymmetry. Using our structure to model a Dicer‐TRBP‐siRNA ternary complex, we show that TRBP's dsRBDs and Dicer's RNase III domains bind a canonical 19 base pair siRNA on opposite sides, supporting a mechanism whereby TRBP influences Dicer‐mediated cleavage accuracy by binding the dsRNA region of the pre‐miRNA during Dicer cleavage.     

Mitochondrial mismatch analysis is insensitive to the mutational process

Mismatch distributions are histograms showing the pattern of nucleotide (or restriction) site differences between pairs of individuals in a sample. They can be used to test hypotheses about the history of population size and subdivision (if selective neutrality is assumed) or about selection (if a constant population size is assumed). Previous work has assumed that mutations never strike the same site twice, an assumption that is called the model of infinite sites. Fortunately, the results are surprisingly robust even when this assumption is violated. We show here that (1) confidence regions inferred using the infinite- sites model differ little from those inferred using a model of finite sites with uniform site-specific mutation rates, and (2) even when site- specific mutation rates follow a gamma distribution, confidence regions are little changed until the gamma shape parameter falls well below its plausible range, to roughly 0.01. In addition, we evaluate and reject the proposition that mismatch waves are produced by pooling data from several subdivisions of a structured population.      

HeLa细胞端粒酶最适反应条件及活性重建

端粒是真核细胞染色体末端的重复ＤＮＡ序列 ,其生物学功能是防止染色体ＤＮＡ降解、末端融合、非正常重组和染色体的缺失[1] .由于存在“末端复制问题” ,随着老化人体细胞端粒重复序列长度不断缩短 ,但在生殖细胞中由于端粒酶的存在 ,端粒序列并不缩短 .端粒酶是由蛋白质和ＲＮＡ构成的核蛋白 ,是依赖ＲＮＡ的ＤＮＡ聚合酶 ,在ＤＮＡ3’端合成端粒重复序列[2 ] .研究表明 ,在 85 %～ 95 %的人肿瘤细胞中可以检测到端粒酶的活性[3 ,4 ] ,而在正常体细胞中除生殖细胞和造血干细胞等极少数细胞中存在端粒酶活性外 ,均检测不到端粒酶活性 ,这…     

Immunolocalization of BRCA1 protein in tumor breast tissue: prescreening of BRCA1 mutation in Tunisian patients with hereditary breast cancer?

BRCA1 is a tumor suppressor gene which is inactivated by mutation in familial breast and ovarian cancers. Over 300 different disease causing germ-line mutations have been described; 60% are unique to an individual family. This diversity and the large size of the gene lead us to search for a prescreening method for BRCA1 mutations. Since BRCA1 is a nuclear protein in normal cells, but reported by some authors to be cytoplasmic in breast tumor cells of patients with BRCA1 mutation, we evaluated immunohistochemistry as a prescreening technique to identify BRCA1 mutations in patients with familial presentation of breast cancer. Using a monoclonal antibody against the carboxy-terminal region of BRCA1, we performed immunohistochemistry on 18 tumor samples from patients with hereditary breast cancer. Cytoplasmic staining of BRCA1 was observed in 10 cases. Of the 18 tumors, 12 (66%) showed either BRCA mutation or BRCA1 accumulation or both, indicating that BRCA1 function might be lost in breast tumor cells not only through mutation, but also via abnormal cytoplasmic location. The immunohistochemical test used in this study would not be efficient as a pre-screening method of deleterious mutations, but it appeared useful to investigate tumor physiology.     

Inefficient nodulation of chickpea (Cicer arietinum L.) in the arid and Saharan climates in Tunisia bySinorhizobium meliloti biovarmedicaginis

The aim of this work is to study the genetic diversity and the symbiotic effectiveness of the natural populations of rhizobia nodulating chickpea (Cicer arietinum L.) in six locations of South Tunisia, where chickpea had never been cultivated. Nodules were observed only in the two soil samples from Gafsa (0.8 nodules per plant) and Tataouine (2 nodules per plant). PCR-RFLP typing of 165 rRNA genes of 42 isolates indicated that all analysed strains showed the same ribotype as the reference strainSinorhizobium meliloti RCR2011. These isolates induced ineffective nodules on chickpea andMedicago sativa; however nodules onMedicago laciniata were effective. Analysis of the symbiotic diversity by PCR-RFLP, of thenifDK spacer suggested that all chickpea isolates from the South belong to the biovarmedicaginis ofS. meliloti. The present paper is, to our knowledge, the first report showing that chickpea is selectively nodulated under soil conditions by a specific biovar ofS. meliloti showing specificity toM. laciniata. The specificity of this interaction as well the impact of this inefficient nodulation on chickpea cultivation needs to be investigated further.     

Unraveling negative biotic interactions determining soil microbial community assembly and functioning

Microbial communities play important roles in all ecosystems and yet a comprehensive understanding of the ecological processes governing the assembly of these communities is missing. To address the role of biotic interactions between microorganisms in assembly and for functioning of the soil microbiota, we used a top-down manipulation approach based on the removal of various populations in a natural soil microbial community. We hypothesized that removal of certain microbial groups will strongly affect the relative fitness of many others, therefore unraveling the contribution of biotic interactions in shaping the soil microbiome. Here we show that 39% of the dominant bacterial taxa across treatments were subjected to competitive interactions during soil recolonization, highlighting the importance of biotic interactions in the assembly of microbial communities in soil. Moreover, our approach allowed the identification of microbial community assembly rule as exemplified by the competitive exclusion between members of Bacillales and Proteobacteriales. Modified biotic interactions resulted in greater changes in activities related to N- than to C-cycling. Our approach can provide a new and promising avenue to study microbial interactions in complex ecosystems as well as the links between microbial community composition and ecosystem function.Subject terms: Soil microbiology, Ecology     

New taxa and combinations in Old World Urticaceae

In anticipation of the publication of full revisions, a diagnosis of a new species of Droguetia is presented together with two new combinations for subspecies of Droguetia iners , a new combination for a species and a variety on Didymodoxa and a new combination for a subspecies of Australina pusilla . The name Elatostema trinerve Hochst. (1845) is shown to be conspecific with and antedate Urera cameroonensis Wedd. (1869). The new combination Urera trinervis is therefore made.     

Seed Priming of Bread Wheat Varieties with Growth Regulators and Nutrients Improves Salt Stress Tolerance Particularly for the Local Genotype

Journal of Plant Growth Regulation - Salt stress is a main factor limiting the production and productivity of wheat in arid and semi-arid zones. The objectives of this study were to compare the...