The insect upper lip (labrum) is a nonsegmental appendage-like structure

SUMMARY The insect upper lip—the labrum—is a lobe-like structure anterior to the mouth opening. Whether the labrum represents a fused pair of segmental appendages or evolved independently is heavily debated. Here, we identify additional similarities of the regulatory gene network active in labrum and trunk appendages. However, we do not find a labral parasegment boundary and we show that labral Tc-Dll expression is independent of Tc-wg and Tc-hh signals. In contrast, Tc-Dll expression in all trunk appendages does require these signals. Finally, we identify crucial differences between the location of the labrum and trunk appendages: the labrum develops in median rather than lateral tissues and is part of an anterior nonsegmental tissue marked by and dependent on Tc-six3 activity. To reconcile these seeming contradictory results, we propose that the genetic network evolved in either labrum or trunk appendages and became redeployed at a novel location to form the other structure.     

Preservation of the Blood Brain Barrier and Cortical Neuronal Tissue by Liraglutide,a Long Acting Glucagon-Like-1 Analogue,after Experimental Traumatic Brain Injury

Cerebral edema is a common complication following moderate and severe traumatic brain injury (TBI), and a significant risk factor for development of neuronal death and deterioration of neurological outcome. To this date, medical approaches that effectively alleviate cerebral edema and neuronal death after TBI are not available. Glucagon-like peptide-1 (GLP-1) has anti-inflammatory properties on cerebral endothelium and exerts neuroprotective effects. Here, we investigated the effects of GLP-1 on secondary injury after moderate and severe TBI. Male Sprague Dawley rats were subjected either to TBI by Controlled Cortical Impact (CCI) or sham surgery. After surgery, vehicle or a GLP-1 analogue, Liraglutide, were administered subcutaneously twice daily for two days. Treatment with Liraglutide (200 μg/kg) significantly reduced cerebral edema in pericontusional regions and improved sensorimotor function 48 hours after CCI. The integrity of the blood-brain barrier was markedly preserved in Liraglutide treated animals, as determined by cerebral extravasation of Evans blue conjugated albumin. Furthermore, Liraglutide reduced cortical tissue loss, but did not affect tissue loss and delayed neuronal death in the thalamus on day 7 post injury. Together, our data suggest that the GLP-1 pathway might be a promising target in the therapy of cerebral edema and cortical neuronal injury after moderate and severe TBI.     

Diel fragrance pattern correlates with olfactory preferences of diurnal and nocturnal flower visitors in Salix caprea (Salicaceae)

Floral scent, often a complex mixture of several volatile organic compounds (VOCs), has generally been interpreted as an adaptation to attract pollinators. However, not many studies have analysed which VOCs are functionally relevant for the reproductive success of a plant. Here, we show that, in Salix caprea (Salicaceae), temporal changes in floral scent emission during the day and night attract two different types of flower visitor: bees during the day and moths during the evening and night. We analysed the contribution of the two flower visitor groups to the reproductive success of the plant. The differences in scent emitted during the peak activity times of flower visitors (day versus night) were quantified and the response of 13 diurnal/nocturnal pollinator taxa to the floral scents was tested using gas chromatographic and electroantennographic techniques. Many of the c. 40 identified scent compounds were physiologically active, and bees and moths responded to nearly identical sets of compounds, although the response strengths differed. In bioassays, bees preferred the most abundant 1,4‐dimethoxybenzene over lilac aldehyde, a compound with increased emission at night, whereas moths preferred lilac aldehyde over 1,4‐dimethoxybenzene. Pollination by wind plus nocturnal pollinators (mainly moths) or by wind alone contributed less to seed set than pollination by wind plus diurnal pollinators (mainly bees). This suggests that the emission of scent during the night and attracting moths have no significant effect on reproductive success. It is possible that the emission of lilac aldehydes and other compounds at night is s result of phylogenetic constraints. Future studies should investigate whether moths may produce a marginal fitness gain in some years and/or some populations. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 624–640.     

Comparison of the structures of the native form of rat liver 5S rRNA and yeast tRNAphe: small-angle and wide-angle X-ray scattering study

The small-angle and wide-angle X-ray scattering of tRNA^phe (yeast) and ribosomal 5S RNA (rat liver) in solution have been analysed and compared. tRNA^phe in solution is folded into a compact L-shaped structure similar to its structure in crystals. The geometry of the secondary structure of the double helical regions is also equivalent to the A-form in the crystalline state. Despite differences between the molar mosses of 5S rRNA (40 000 g mol^?1) and tRNA^phe (25 000 g mol^?1), and the fact that the 5S rRNA molecule is more anisometric than the tRNA^phe molecule, there are many structural similarities. The geometrical parameters of the secondary structure of double helical regions in both RNA molecules are almost identical; the mean rise per base pair is about 0.253–0.28 nm and the mean turn angle is about 32.5–33.5. Identical cross-sectional radii of gyration, R_sq,1 ≈ 1.16 nm and R_sq,2 = 0.92 nm, identical molar mass per unit length, , and a mean thickness of the molecules D ≈ 1.65 nm suggest a similar, nearly coplanar organization of isolated, double helical arms. Furthermore, there are compact regions in the central parts of both molecules, which are the sites of tertiary interactions in the tRNA^phe molecule and are a potential site of tertiary interactions in the SS rRNA molecule for stabilization of the complicated L-shape of the two molecules. Both molecules have a pseudo-twofold axis,w hich may play a role in recognition for binding of specific proteins.     

Crystal Structures of Wzb of Escherichia coli and CpsB of Streptococcus pneumoniae, Representatives of Two Families of Tyrosine Phosphatases that Regulate Capsule Assembly

Many Gram-positive and Gram-negative bacteria utilize polysaccharide surface layers called capsules to evade the immune system; consequently, the synthesis and export of the capsule are a potential therapeutic target. In Escherichia coli K-30, the integral membrane tyrosine autokinase Wzc and the cognate phosphatase Wzb have been shown to be key for both synthesis and assembly of capsular polysaccharides. In the Gram-positive bacterium Streptococcus pneumoniae, the CpsCD complex is analogous to Wzc and the phosphatase CpsB is the corresponding cognate phosphatase. The phosphatases are known to dephosphorylate their corresponding autokinases, yet despite their functional equivalence, they share no sequence homology. We present the structure of Wzb in complex with phosphate and high-resolution structures of apo-CpsB and a phosphate-complexed CpsB. We show that both proteins are active toward Wzc and thereby demonstrate that CpsB is not specific for CpsCD. CpsB is a novel enzyme and represents the first solved structure of a tyrosine phosphatase from a Gram-positive bacterium. Wzb and CpsB have completely different structures, suggesting that they must operate by very different mechanisms. Although the mechanism of Wzb can be inferred from previous studies, CpsB appears to have a tyrosine phosphatase mechanism not observed before. We propose a chemical mechanism for CpsB based on site-directed mutagenesis and structural data.