Enhancing mating performance after juvenile hormone treatment in Anastrepha fraterculus: a differential response in males and females acts as a physiological sexing system

Methoprene (a mimic of juvenile hormone) treatment can reduce the time required for sexual maturation in Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) males under laboratory conditions, supporting its use as a treatment for sterile males within the context of the sterile insect technique (SIT). We evaluated sexual behaviour, mating competitiveness of methoprene-treated males, and female readiness to mate after methoprene-treatment in field cages. The study involved two strains of A. fraterculus from Argentina and Peru, which show several polymorphisms in relation to their sexual behaviour. We also analyzed whether methoprene treatment affected male and/or female behaviour in the same way in these two strains. Methoprene-treated males were equally competitive with untreated mature males, and became sexually competitive 6 days after emergence (3–4 days earlier than untreated males). In contrast, methoprene did not induce sexual maturation in females or, at least, it did not induce a higher rate of mating in 7-day-old females. These results were observed both for the Argentina and the Peru strains. Altogether, our results indicate that methoprene treatment produces sexually competitive males in field cages. In the absence of a genetic sexing system, and when sterile males and females of A. fraterculus are released simultaneously, the fact that females do not respond as do males to the methoprene treatment acts as a physiological sexing effect. Therefore, in the presence of mainly sexually immature sterile females, released sexually mature sterile males would have to disperse in search of wild fertile females, thereby greatly reducing matings among the released sterile insects and thus enhancing sterile insect technique efficiency.     

Smokers with CT Detected Emphysema and No Airway Obstruction Have Decreased Plasma Levels of EGF,IL-15, IL-8 and IL-1ra

Rationale

Low-grade inflammation and emphysema have been shown to be associated with an increased risk of lung cancer. However, the systemic inflammatory response in patients with emphysema is still unknown.

Objective

To compare the plasma cytokine profiles in two groups of current or former smokers without airway obstruction: a control group of individuals without computed tomography (CT) detected emphysema vs. a study group of individuals with CT detected emphysema.

Methods

Subjects underwent a chest CT, spirometry, and determination of EGF, IL-15, IL-1ra, IL-8, MCP-1, MIP-1β, TGFα, TNFα, and VEGF levels in plasma. Cytokine levels in each group were compared adjusting for confounding factors.

Results

160 current smokers and former smokers without airway obstruction participated in the study: 80 without emphysema and 80 subjects with emphysema. Adjusted group comparisons revealed significant reductions in EGF (−0.317, p = 0.01), IL-15 (−0.21, p = 0.01), IL-8 (−0.180, p = 0.02) and IL-1ra (−0.220, p = 0.03) in subjects with emphysema and normal spirometry.

Conclusions

Current or former smokers expressing a well-defined disease characteristic such as emphysema, has a specific plasma cytokine profile. This includes a decrease of cytokines mainly implicated in activation of apoptosis or decrease of immunosurveillance. This information should be taken into account when evaluated patients with tobacco respiratory diseases.     

Mutational Spectrum of Semaphorin 3A and Semaphorin 3D Genes in Spanish Hirschsprung patients

Hirschsprung disease (HSCR, OMIM 142623) is a developmental disorder characterized by the absence of ganglion cells along variable lengths of the distal gastrointestinal tract, which results in tonic contraction of the aganglionic colon segment and functional intestinal obstruction. The RET proto-oncogene is the major gene associated to HSCR with differential contributions of its rare and common, coding and noncoding mutations to the multifactorial nature of this pathology. In addition, many other genes have been described to be associated with this pathology, including the semaphorins class III genes SEMA3A (7p12.1) and SEMA3D (7q21.11) through SNP array analyses and by next-generation sequencing technologies. Semaphorins are guidance cues for developing neurons implicated in the axonal projections and in the determination of the migratory pathway for neural-crest derived neural precursors during enteric nervous system development. In addition, it has been described that increased SEMA3A expression may be a risk factor for HSCR through the upregulation of the gene in the aganglionic smooth muscle layer of the colon in HSCR patients. Here we present the results of a comprehensive analysis of SEMA3A and SEMA3D in a series of 200 Spanish HSCR patients by the mutational screening of its coding sequence, which has led to find a number of potentially deleterious variants. RET mutations have been also detected in some of those patients carrying SEMAs variants. We have evaluated the A131T-SEMA3A, S598G-SEMA3A and E198K-SEMA3D mutations using colon tissue sections of these patients by immunohistochemistry. All mutants presented increased protein expression in smooth muscle layer of ganglionic segments. Moreover, A131T-SEMA3A also maintained higher protein levels in the aganglionic muscle layers. These findings strongly suggest that these mutants have a pathogenic effect on the disease. Furthermore, because of their coexistence with RET mutations, our data substantiate the additive genetic model proposed for this rare disorder and further support the association of SEMAs genes with HSCR.     

Somatic embryogenesis in holm oak male catkins

Somatic embryogenesis (SE) of tree species is the most promising method for the implementation of multivarietal forestry and for biotechnological approaches. To date, however, the application of this technology to mature trees is restricted to a few species. This is the first report on the induction of SE from male catkins of 100-year-old holm oaks (Quercus ilex L.). Embryogenic competence was mainly dependent on genotype and restricted to the most advanced catkin developmental stage with distinguishable closed flowers along the axis. Following a three-stage treatment procedure, embryogenic response (frequencies up 3.3 %) was obtained in three [Remedio, Villar del Arzobispo (VA) and Hunde (HU)] out of the five genotypes evaluated. In the culture conditions tested, the preferred protocol to induce SE in holm oak catkins should include: induction on MS medium with 6-benzyladenine and naphthaleneacetic acid, subculture onto medium with a reduced concentration of both plant growth regulators and a final transference to medium without growth regulators. Under these conditions, cotyledonary-stage somatic embryos developed from brown calli with or without nodular structures. Secondary SE, favored by the addition of sorbitol to the manifestation medium, allowed the establishment of 14 embryogenic lines belonging to VA and HU genotypes. Histological observations of the proliferating cultures revealed the presence of globular, torpedo and cotyledonary somatic embryos. Somatic embryos were diploid as verified by flow cytometry analysis, suggesting that they originated from the perianthic tissue of the male flower.     

A trait-based approach predicting community assembly and dominance of microbial invasive species

Understanding the mechanisms underlying community assembly helps to define success and susceptibility to biological invasions. Here, we explored phytoplankton community assembly following niche and neutral paradigms and using a trait-based approach. Under the hypothesis that the morphology-based functional groups (MBFG) clusters species with similar niche, we analysed how trait-related differences in fitness influence dominance of an invasive species. This was based on literature review, field data and model simulations. We predict that invading species can be dominant if: 1) do not belong to the local MBFG but use unexploited areas of the niche, or 2) belong to the resident MBFG but exhibit a higher fitness due to a particular combination of traits. The invasive dinoflagellate Ceratium furcoides was used as the model species to evaluate these hypotheses, its morphological (e.g. volume) and physiological (e.g. growth rates) traits were compared with species from the same (V: photosynthetic flagellates) and different (VII: colonial cyanobacteria) MBFG. Fitness was estimated using models parametrized with MBFG rates (R*, ability to draw down phosphate) under different environmental conditions (i.e. flushing). Results contributed to support both hypotheses. First, the alternation of C. furcoides and cyanobacteria dominance was explained by the use of different niches. Secondly, species from MBFG V were dominant under similar environments. Within this group V C. furcoides showed higher fitness under low flushing and high predation, advantage provided by a distinctive combination of traits. The application of trait-based approaches to represent the niche and estimate fitness along environmental gradients was useful to evaluate community assembly and can be used to predict the dominance of microbial species invasions.     

Nesaecrepida infuscata: a biological control agent of the invasive plant Mimosa pigra

Mimosa pigra L. is a serious weed of wetlands of Australia, Asia and Africa. A suite of established biocontrol agents have been introduced in Australia and some Asian countries, but better control is needed. Nesaecrepida infuscata (Schaeffer) (Coleoptera: Chrysomelidae) is a common insect on M. pigra in tropical America. The larvae develop on the roots while the adults feed on the leaves. As both roots and leaves of M. pigra are relatively undamaged in the introduced range, this species has potential to limit the growth, survival and seed production. Furthermore, it is abundant in the dry season and so inflicts damage when most other agents are not active. In host specificity tests, larvae did not develop on any of the 65 test plant species other than M. pigra. Adult feeding on test plant species other than M. pigra was minimal. Based on these results, this insect has been released in Australia.     

Native anurans threatened by the alien tree Ligustrum lucidum in a seasonal subtropical forest

Biological Invasions - Amphibians are declining globally from diverse and complex causes, with one of the most prevalent being alien species invasion. Alien woody invaders, such as the evergreen...     

The Phosphorylated Pathway of Serine Biosynthesis Is Essential Both for Male Gametophyte and Embryo Development and for Root Growth in Arabidopsis

This study characterizes the phosphorylated pathway of Ser biosynthesis (PPSB) in Arabidopsis thaliana by targeting phosphoserine phosphatase (PSP1), the last enzyme of the pathway. Lack of PSP1 activity delayed embryo development, leading to aborted embryos that could be classified as early curled cotyledons. The embryo-lethal phenotype of psp1 mutants could be complemented with PSP1 cDNA under the control of Pro35S (Pro35S:PSP1). However, this construct, which was poorly expressed in the anther tapetum, did not complement mutant fertility. Microspore development in psp1.1/psp1.1 Pro35S:PSP1 arrested at the polarized stage. The tapetum from these lines displayed delayed and irregular development. The expression of PSP1 in the tapetum at critical stages of microspore development suggests that PSP1 activity in this cell layer is essential in pollen development. In addition to embryo death and male sterility, conditional psp1 mutants displayed a short-root phenotype, which was reverted in the presence of Ser. A metabolomic study demonstrated that the PPSB plays a crucial role in plant metabolism by affecting glycolysis, the tricarboxylic acid cycle, and the biosynthesis of amino acids. We provide evidence of the crucial role of the PPSB in embryo, pollen, and root development and suggest that this pathway is an important link connecting primary metabolism with development.