Wrap attack of the spider <Emphasis Type="Italic">Achaearanea tepidariorum</Emphasis> (Araneae: Theridiidae) by preying on mealybugs <Emphasis Type="Italic">Planococcus citri</Emphasis> (Homoptera: Pseudococcidae)

Predation by Achaearanea tepidariorum (Koch 1841) on mealybugs Planococcus citri (Risso 1813) is facilitated by the design of its web, which features a tangle of sticky gumfooted lines, and wrap attacks as well as the ability to handle the prey, whose body is covered with a waxy secretion, via silk. Crawling, i.e., wingless, mealybugs (in particular those in the nymphal stages and adult females and, to a lesser extent, winged males) are caught by means of the gumfooted lines, covered with globules of an adhesive secretion. The process of wrap attack and subsequent handling of the captured prey is a series of the following consecutive events: (1) confining and immobilising the mealybugs with sticky silk; (2) biting with chelicerae and paralyzing the prey with a toxin; (3) detaching the confined prey, attached to the tense threads, from the plant surface and catapulting it toward the central section of the web; (4) wrapping the catapulted prey in viscid silk emitted by the spinning apparatus; (5) transporting the wrapped prey to the central section of the web; (6) wrapping the prey in the central section of the web in nonsticky silk, whose tufts are present in this part of the web even before the attack; (7) filling the prey with digestive fluid; (8) sucking the prey empty; and (9) cleaning the chelicerae and mouth parts. The process of silk tuft wrapping was described for the first time. The described ability to hunt mealybugs implies the possibility of using A. tepidariorum spiders for biological control of these pests.     

Gene targeting in maize by somatic ectopic recombination

Low transformation efficiency and high background of non‐targeted events are major constraints to gene targeting in plants. We demonstrate here applicability in maize of a system that reduces the constraint from transformation efficiency. The system requires regenerable transformants in which all of the following elements are stably integrated in the genome: (i) donor DNA with the gene of interest adjacent to sequence for repair of a defective selectable marker, (ii) sequence encoding a rare‐cutting endonuclease such as I‐SceI, (iii) a target locus (TL) comprising the defective selectable marker and I‐SceI cleavage site. Typically, this requires additional markers for the integration of the donor and target sequences, which may be assembled through cross‐pollination of separate transformants. Inducible expression of I‐SceI then cleaves the TL and facilitates homologous recombination, which is assayed by selection for the repaired marker. We used bar and gfp markers to identify assembled transformants, a dexamethasone‐inducible I‐SceI::GR protein, and selection for recombination events that restored an intact nptII. Applying this strategy to callus permitted the selection of recombination into the TL at a frequency of 0.085% per extracted immature embryo (29% of recombinants). Our results also indicate that excision of the donor locus (DL) through the use of flanking I‐SceI cleavage sites may be unnecessary, and a source of unwanted repair events at the DL. The system allows production, from each assembled transformant, of many cells that subsequently can be treated to induce gene targeting. This may facilitate gene targeting in plant species for which transformation efficiencies are otherwise limiting.     

Life history of the sandy beach amphipod Deshayesorchestia deshayesii (Crustacea: Talitridae) from Bizerta beach (North of Tunisia)

Population dynamics and reproductive activity of the amphipod Deshayesorchestia deshayesii were studied monthly from June 2007 to December 2008 in Bizerta beach. During this period, 6577 specimens of D. deshayesii were identified; the sex ratio was female biased, with a mean of the monthly sex ratios equal to 0.21?±?0.12. Due to the absence of embryos or eggs in the female brood pouches and juveniles in the samples, results suggested that the reproductive season extended from April to November, with a sexual resting period during winter from December to March. Brood size varied between 4 and 17 eggs and fecundity appeared to be correlated with female size. Six cohorts were identified on the first sampling date. Additionally, 12 new cohorts were detected during the study period. Life span was estimated at 5–7?months depending on the time of birth. Cohorts that appeared at the beginning of the reproductive period tended to have shorter lives than those born later in the season. These results suggest that D. deshayesii can be considered as a semi-annual species, with iteroparous females.     

Cadmium,copper and zinc toxicity effects on growth,proline content and genetic stability of Solanum nigrum L., a crop wild relative for tomato; comparative study

Plants like other organisms are affected by environmental factors. Cadmium, copper and zinc are considered the most important types of pollutants in the environment. In this study, a comparison of growth and biochemical parameters between the crop wild relative (CWR) Solanum nigrum versus its cultivated relative Solanum lycopersicum to different levels of Cu, Zn and Cd stress were investigated. The presence of ZnSO₄ and CuSO₄ in Murashige and Skoog medium affected severely many growth parameters (shoot length, number of roots and leaves, and fresh weight) of both S. nigrum and S. lycopersicum at high levels. On the other hand, CdCl₂ significantly reduced most of the studied growth parameters for both species. S. nigrum exhibited higher tolerance than S. lycopersicum for all types of stress. In addition, results show that as stress level increased in the growing medium, proline content of both S. nigrum and S. lycopersicum increased. A significant difference was observed between the two species in proline accumulation as a result of stress. In addition, a higher accumulation rate was observed in the crop wild relative (S. nigrum) than in cultivated S. lycopersicum. Changes in Inter-simple sequence repeat (ISSR) pattern of CuSO₄ treated S. nigrum and S. lycopersicum plants were also observed. In conclusion, based on growth and biochemical analysis, S. nigrum showed higher level of metals tolerance than S. lycopersicum which indicates the possibility of using it as a crop wild relative for S. lycopersicum.     

Decreasing Tropomyosin Phosphorylation Rescues Tropomyosin-induced Familial Hypertrophic Cardiomyopathy

Studies indicate that tropomyosin (Tm) phosphorylation status varies in different mouse models of cardiac disease. Investigation of basal and acute cardiac function utilizing a mouse model expressing an α-Tm protein that cannot be phosphorylated (S283A) shows a compensated hypertrophic phenotype with significant increases in SERCA2a expression and phosphorylation of phospholamban Ser-16 (Schulz, E. M., Correll, R. N., Sheikh, H. N., Lofrano-Alves, M. S., Engel, P. L., Newman, G., Schultz Jel, J., Molkentin, J. D., Wolska, B. M., Solaro, R. J., and Wieczorek, D. F. (2012) J. Biol. Chem. 287, 44478–44489). With these results, we hypothesized that decreasing α-Tm phosphorylation may be beneficial in the context of a chronic, intrinsic stressor. To test this hypothesis, we utilized the familial hypertrophic cardiomyopathy (FHC) α-Tm E180G model (Prabhakar, R., Boivin, G. P., Grupp, I. L., Hoit, B., Arteaga, G., Solaro, R. J., and Wieczorek, D. F. (2001) J. Mol. Cell. Cardiol. 33, 1815–1828). These FHC hearts are characterized by increased heart:body weight ratios, fibrosis, increased myofilament Ca²⁺ sensitivity, and contractile defects. The FHC mice die by 6–8 months of age. We generated mice expressing both the E180G and S283A mutations and found that the hypertrophic phenotype was rescued in the α-Tm E180G/S283A double mutant transgenic animals; these mice exhibited no signs of cardiac hypertrophy and displayed improved cardiac function. These double mutant transgenic hearts showed increased phosphorylation of phospholamban Ser-16 and Thr-17 compared with the α-Tm E180G mice. This is the first study to demonstrate that decreasing phosphorylation of tropomyosin can rescue a hypertrophic cardiomyopathic phenotype.     

Molecular characterization of extended-spectrum-beta-lactamase-producing Escherichia coli isolates from red foxes in Portugal

The presence of broad-spectrum-cephalosporin-resistant Escherichia coli isolates and the implicated mechanisms of resistance and virulence factor genes were investigated in red fox (Vulpes vulpes) in Portugal. Cefotaxime-resistant E. coli isolates were isolated from two of 52 fecal samples (4 %), being both ESBL producers. The β-lactamase genes found in the two isolates were bla _SHV-12 + bla _TEM-1b. The tet(A) and sul2 genes were also detected in these isolates, together with the non-classical class 1 integron (intI1-dfrA12-orfF-aadA2-cmlA1-aadA1-qacH-IS440-sul3) with the PcH1 promoter. The two isolates belonged to the phylogroup A. Amino acid changes in GyrA (S83L + D87G) and ParC (S80I) proteins were identified in our study. Concerning MLST typing, both isolates were assigned to ST1086, never found before in wild animals, and they presented closely related PFGE patterns. This study reveals the presence of ESBL-producing E. coli isolates, in a wild ecosystem, which could be disseminated through the environment to other niches.     

Proteome of a methicillin-resistant Staphylococcus aureus clinical strain of sequence type ST398

Proteomics is a powerful tool to analyze the differences in gene expression of bacterial strains. Staphylococcus aureus has long been recognized as an important pathogen in human disease. In order to investigate this pathogen, the proteome of a clinical methicillin-resistant S. aureus (MRSA) strain of the sequence type ST398 was determined using 2-DE. Using 2-DE we obtained a total of 105 spots the MRSA strain. Furthermore in correlation with bioinformatic databases, they allowed accurate identification and characterization of proteins, resulting in 227 identified proteins. There were found proteins related to basic function of the cell, but also proteins related to virulence like catalase, specific of S. aureus species, and proteins related to antibiotic resistance. Proteins associated with antibiotic resistance or virulence factors are related to genomic databases. The most abundant classes identified involved glycolysis, energy production, one-carbon metabolism, and oxidation-reduction process, all of which reflect an active metabolism. These results highlight the importance of proteomics to deepen in the knowledge of protein expression of MRSA strain of the lineage ST398, microorganism with diverse and important resistance mechanisms. With this proteome map we have an essential tool for a better understanding of this pathogen and providing new data for protein databases. This article is part of a Special Issue entitled: Proteomics: The clinical link.