CRISPR Screens Uncover Genes that Regulate Target Cell Sensitivity to the Morphogen Sonic Hedgehog

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Four years host–parasitoid food web: testing sampling effort on trophic levels

Incomplete sampling is a major problem affecting data quality with respect to food webs. We described a host–parasitoid food web based on data from four years of sampling, evaluated the dataset robustness of the food web, and tested the hypothesis that different trophic levels require different sampling efforts. We sampled Senegalia tenuifolia fruits at eight sampling sites in three areas, during four years (2011–2014) in the Brazilian cerrado (savanna). We recorded 26 insect species in three trophic levels associated with S. tenuifolia. For species accumulation curves, all insect trophic levels, areas and years reached the asymptote, except for one area. The cumulative species richness in each trophic level suggested that the third level (primary parasitoid) should be sampled for a longer time than the second and fourth levels, supporting our hypothesis. In conclusion, the sampling effort employed was sufficient to assess most of the insect species richness, and provided a high-quality and well-represented host-parasitoid food web, even though trophic levels require different efforts.     

Inhibition of the AnxA1/FPR1 autocrine axis reduces MDA-MB-231 breast cancer cell growth and aggressiveness in vitro and in vivo

Breast Cancer (BC) is a highly heterogeneous disease whose most aggressive behavior is displayed by triple-negative breast cancer (TNBC), which lacks an efficient targeted therapy. Despite its controversial role, one of the proteins that having been linked with BC is Annexin A1 (AnxA1), which is a Ca⁺² binding protein that acts modulating the immune system, cell membrane organization and vesicular trafficking. In this work we analyzed tissue microarrays of BC samples and observed a higher expression of AnxA1 in TNBCs and in lymph node metastasis. We also observed a positive correlation in primary tumors between expression levels of AnxA1 and its receptor, FPR1. Despite displaying a lesser strength, this correlation also exists in BC lymph node metastasis. In agreement, we have found that AnxA1 was highly expressed and secreted in the TNBC cell line MDA-MB-231 that also expressed high levels of FPR1. Furthermore, we demonstrated, by using the specific FPR1 inhibitor Cyclosporin H (CsH) and the immunosuppressive drug Cyclosporin A (CsA), the existence of an autocrine signaling of AnxA1 through the FPR1. Such signaling, elicited by AnxA1 upon its secretion, increased the aggressiveness and survival of MDA-MB-231 cells. In this manner, we demonstrated that CsA works very efficiently as an FPR1 inhibitor. Finally, by using CsA, we demonstrated that FPR1 inhibition decreased MDA-MB-231 tumor growth and metastasis formation in nude mice. These results indicate that FPR1 inhibition could be a potential intervention strategy to manage TNBCs displaying the characteristics of MDA-MB-231 cells. FPR1 inhibition can be efficiently achieved by CsA.     

Lopesia indaiensis (Diptera,Cecidomyiidae), a new species of gall midge feeding on Andira fraxinifolia Benth (Fabaceae), an endemic plant in Brazil

Lopesia indaiensis (Diptera, Cecidomyiidae), a new species of gall midge found causing galls on Andira fraxinifolia (Fabaceae), an endemic plant species in Brazil, is described based on larva, pupa, male and female. L. indaiensis galls were collected in Dores do Indaiá, State of Minas Gerais, Southeastern Brazil. Larvae were removed from the galls and pupae and adults were obtained by rearing. The specimens were mounted on slides and the most important morphological characters were illustrated. The new species was compared to the other species of Lopesia.     

Floral scent chemistry within the genus Linnaea (Caprifoliaceae)

‘Beauty bush’ and ‘twin flower’ are common names attributed to two well‐recognizable species belonging to the genus Linnaea (16 spp.) – L. amabilis and L. borealis – long admired by botanists and gardeners for their perfumed paired bell‐shaped flowers. In the present study, we investigated their floral scent compositions through gas chromatography – mass spectrometry (GC‐MS) analysis of dynamic headspace samples. Because the flowers of L. borealis in wild populations are fragrant both during the day and in the evening, circadian variation of scent emission was also assessed for this species. In total, 26 chemical compounds comprise the floral scent bouquets of L. amabilis and L. borealis, identified as monoterpenes (14), benzenoids and phenylpropanoids (5), aliphatics (3), sesquiterpenes (3) and irregular terpenes (1). Whereas monoterpenes, notably (‐)‐α‐ and β‐pinene, dominated the scent of L. amabilis (over 82% relative abundance), benzene derivates: 1,4 dimethoxybenzene, anisaldehyde, 2‐phenylethanol, benzaldehyde and nicotinaldehyde were exclusive to analysed headspace samples of L. borealis, accounting for 52% to 100% of their relative compositions, in three Swedish populations. A southwestern Finnish population was characterized by the four first mentioned benzenoid compounds and large amounts of (‐)‐α‐ and β‐pinenes plus two aliphatic substances. The scent compounds identified for both species are ubiquitous and may serve as generalist attractants/stimulants for a broad assortment of anthophilous insects. The basic work on the flower scent of L. amabilis and L. borealis should inspire studies of their pollination biology, primarily the behaviour‐guiding roles of the characteristic emitted volatiles.     

Frequency modulation of theta volleys of septal neurons during rhythmic oligosynaptic stimulation in the rabbit

Activity of the neurones with stable theta-bursts was recorded extracellularly in intact and hippocampectomized septum of unanaesthetized chronic rabbits during low-frequency (3-17 Hz) stimulation of horizontal limb of the diagonal band or the lateral septal nucleus. Gradual entrainment and phase-locking of the spontaneous theta-cycles occurred. Two types of entrainment were observed: "entrainment by pause", where interburst interval was reset by the stimuli; and "entrainment by burst", where bursts were time-locked to the stimuli. Such reorganization of the spontaneous bursts occurred in a narrow frequency range of stimulation (from 4 Hz up to 9-12 Hz), with the best resonance following in the range of "basic" theta frequencies of the awake rabbit (5-6 Hz). With stimulation beyond the theta-range three phenomena occurred: shift of the burst frequencies to higher or lower harmonics of stimulation frequencies; complex interactions of basic background frequency with the rhythm of stimulation ("beating"); escape from the influence of the stimuli with return to background theta-burst frequency.     

DNA-duplexes with phosphoamide bond: interaction with restriction endonucleases EcoRII and SsoII

We studied the interaction of EcoRII and SsoII restriction endonucleases with synthetic DNA duplexes, containing 3'N----5'P and 3'P----5'N phosphoamide internucleotide bonds in one of the cleavage points. Enzymatic hydrolysis of the modified strand of the duplexes is blocked in all cases. The presence of phosphoamide bonds was found to reduce the rate of cleavage of the natural strand by EcoRII and to have no influence in case of SsoII. Properties of the EcoRII endonuclease complex with its substrate, containing non-cleavable 3'N----5'P internucleotide bonds in each cleavage point, were examined. In the presence of Mg2+ ions the equilibrium association constant of the enzyme-substrate complex is 3-fold reduced, and the dissociation rate constant of the complex is increased by 1.5 times.     

Interaction of restriction and modification enzyme EcoRII with synthetic DNA fragments. VII. The study of complex-formation of endonuclease EcoRII with substrates containing natural and modified recognition sites

As shown by a nitrocellulose filter binding assay, in the absence of Mg2+ EcoRII restriction endonuclease binds specifically to a set of synthetic concatemer DNA duplexes of varying chain length, containing natural and modified recognition sites of this enzyme. The binding of the substrates with the central AT, TT or AA-pair in the recognition site decreases at AT greater than TT much greater than AA. Substitution of the pyrophosphate bond at the cleavage site for the phosphodiester or phosphoramide bond produces little influence on the stability of the complexes. The affinity of the enzyme for nonspecific sites is two orders of magnitude less than that for the specific EcoRII sequences. Equilibrium association constant for a substrate with one recognition site is 3.9 X 10(8) M-1. Addition of Mg2+ leads to the destabilization of the EcoRII endonuclease complex with DNA duplex, containing pyrophosphate bonds. The dissociation rate constants and the lifetime of the EcoRII endonuclease--synthetic substrates complexes have been determined.     

Effect of ionizing radiation on the lipid composition of aminoacyl-tRNA-synthetase complexes

The effect of X-radiation (0.21 C/kg) on a lipid component of aminoacyl-tRNA-synthetase complexes from rat liver (for instance, phospholipids, neutral lipids, and prostaglandins) has been studied. The content of prostaglandins and lysophosphatidyl choline increases and that of phospholipids and neutral lipids decreases 60 min after irradiation. In 24 h, the content of prostaglandins, fatty acids, cholesterol, and phosphatidyl ethanolamine approaches the control level.