The Carbohydrate-linked Phosphorylcholine of the Parasitic Nematode Product ES-62 Modulates Complement Activation

Parasitic nematodes manufacture various carbohydrate-linked phosphorylcholine (PCh)-containing molecules, including ES-62, a protein with an N-linked glycan terminally substituted with PCh. The PCh component is biologically important because it is required for immunomodulatory effects. We showed that most ES-62 was bound to a single protein, C-reactive protein (CRP), in normal human serum, displaying a calcium-dependent, high-avidity interaction and ability to form large complexes. Unexpectedly, CRP binding to ES-62 failed to efficiently activate complement as far as the C3 convertase stage in comparison with PCh-BSA and PCh-containing Streptococcus pneumoniae cell wall polysaccharide. C1q capture assays demonstrated an ES-62-CRP-C1q interaction in serum. The three ligands all activated C1 and generated C4b to similar extents. However, a C2a active site was not generated following ES-62 binding to CRP, demonstrating that C2 cleavage was far less efficient for ES-62-containing complexes. We proposed that failure of C2 cleavage was due to the flexible nature of carbohydrate-bound PCh and that reduced proximity of the C1 complex was the reason that C2 was poorly cleaved. This was confirmed using synthetic analogues that were similar to ES-62 only in respect of having a flexible PCh. Furthermore, ES-62 was shown to deplete early complement components, such as the rate-limiting C4, following CRP interaction and thereby inhibit classical pathway activation. Thus, flexible PCh-glycan represents a novel mechanism for subversion of complement activation. These data illustrate the importance of the rate-limiting C4/C2 stage of complement activation and reveal a new addition to the repertoire of ES-62 immunomodulatory mechanisms with possible therapeutic applications.     

Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) and Cyclic ADP-Ribose (cADPR) Mediate Ca2+ Signaling in Cardiac Hypertrophy Induced by β-Adrenergic Stimulation

Ca²⁺ signaling plays a fundamental role in cardiac hypertrophic remodeling, but the underlying mechanisms remain poorly understood. We investigated the role of Ca²⁺-mobilizing second messengers, NAADP and cADPR, in the cardiac hypertrophy induced by β-adrenergic stimulation by isoproterenol. Isoproterenol induced an initial Ca²⁺ transients followed by sustained Ca²⁺ rises. Inhibition of the cADPR pathway with 8-Br-cADPR abolished only the sustained Ca²⁺ increase, whereas inhibition of the NAADP pathway with bafilomycin-A1 abolished both rapid and sustained phases of the isoproterenol-mediated signal, indicating that the Ca²⁺ signal is mediated by a sequential action of NAADP and cADPR. The sequential production of NAADP and cADPR was confirmed biochemically. The isoproterenol-mediated Ca²⁺ increase and cADPR production, but not NAADP production, were markedly reduced in cardiomyocytes obtained from CD38 knockout mice. CD38 knockout mice were rescued from chronic isoproterenol infusion-induced myocardial hypertrophy, interstitial fibrosis, and decrease in fractional shortening and ejection fraction. Thus, our findings indicate that β-adrenergic stimulation contributes to the development of maladaptive cardiac hypertrophy via Ca²⁺ signaling mediated by NAADP-synthesizing enzyme and CD38 that produce NAADP and cADPR, respectively.     

Culex tritaeniorhynchus: Failure to detect heterosis in the life table characteristics of outcrossed laboratory colonies

Intra and interstrain crosses were made between unselected and inbred adults of the Balloki and Peshawar, Pakistan, laboratory colonies of C. tritaeniorhynchus and life tables were constructed for their progeny. No overall heterosis effects were detected. Inbreeding severely reduced fertility and fecundity and lowered the innate capacity for increase. Interstrain crosses among inbred adults restored some vigor, but all life table estimates relating to fecundity were significantly less than crosses among the unselected adults. Thus, outcrosses among laboratory-adapted colonies did not appear to impart marked heterosis and would probably not enhance the vigor of males used for genetic control.

---

Zusammenfassung Intra- und Interstammkreuzungen wurden zwischen unselektionierten und ingezüchteten Insekten der Balloki- und Peshawar-Laboratoriumskolonien von C. tritaeniorhynchus durchgeführt und es wurden Life Tables für ihre Nachkommenschaft erstellt. Dabei konnten keine allgemeinen Heterosis-effekte festgestellt werden. Inzucht verminderte die Fertilität und Fekundität stark und reduzierte die genetische Vermehrungsfähigkeit. Interstammkreuzungen zwischen Inzuchtinsekten brachte etwas Vigor zurück, aber alle Life Table-Schätzungen im Hinblick auf Fekundität waren gesichert tiefer als bei Kreuzungen zwischen nicht selektionierten Insekten. Demnach scheinen Kreuzungen zwischen verschiedenen dem Laboratorium angepassten Kolonien keine ausgeprägte Heterosis zu bringen. Sie würden wahrscheinlich die Qualität von Männchen und Weibchen, die für die genetische Bekämpfung verwendet werden, nicht verbessern.

     

Amblyomin-X,a recombinant Kunitz-type inhibitor,regulates cell adhesion and migration of human tumor cells

ABSTRACT

In a tumor microenvironment, endothelial cell migration and angiogenesis allow cancer to spread to other organs causing metastasis. Indeed, a number of molecules that are involved in cytoskeleton re-organization and intracellular signaling have been investigated for their effects on tumor cell growth and metastasis. Alongside that, Amblyomin-X, a recombinant Kunitz-type protein, has been shown to reduce metastasis and tumor growth in in vivo experiments. In the present report, we provide a mechanistic insight to these antitumor effects, this is, Amblyomin-X modulates Rho-GTPases and uPAR signaling, and reduces the release of MMPs, leading to disruption of the actin cytoskeleton and decreased cell migration of tumor cell lines. Altogether, our data support a role for Amblyomin-X as a novel potential antitumor drug.     

D224V and S128Y mutation in FSHRED influence thumb movement differentially: An intricate insight gained by short-term molecular dynamics simulation

Follicle-stimulating hormone-follicle-stimulating hormone receptor (FSH-FSHR) interaction is one of the most thoroughly studied signaling pathways primarily because of being implicated in sexual reproduction in mammals by way of maintaining gonadal function and sexual fertility. Despite material advances in understanding the role of point mutations, their mechanistic basis in FSH-FSHR signaling is still confined to mystically altered behavior of sTYS335 (sulfated tyrosine) yet lacking a substantial theory. To understand the structural basis of receptor modulation, we choose two behaviorally contradicting mutations, namely S128Y (activating) and D224Y (inactivating), found in FSH receptor responsible for ovarian hyperstimulation syndrome and ovarian dysgenesis, respectively. Using short-term molecular dynamics simulations, the atomic scale investigations reveal that the binding pattern of sTYS with FSH and movement of the thumb region of FSHR show distinct contrasting patterns in the two mutants, which supposedly could be a critical factor for differential FSHR behavior in activating and inactivating mutations.     

Exploration of Genetic Pattern of Phenological Traits in Wheat (<i>Triticum aestivum</i> L.) under Drought Stress

Drought is the major detrimental environmental factor for wheat (Triticum aestivum L.) production. The exploration of genetic patterns underlying drought tolerance is of great significance. Here we report the gene actions controlling the phenological traits using the line × tester model studying 27 crosses and 12 parents under normal irrigation and drought conditions. The results interpreted via multiple analysis (mean performance, correlations, principal component, genetic analysis, heterotic and heterobeltiotic potential) disclosed highly significant differences among germplasm. The phenological waxiness traits (glume, boom, and sheath) were strongly interlinked. Flag leaf area exhibits a positive association with peduncle and spike length under drought. The growing degree days (heat-units) greatly influence spikelets and grains per spike, however, the grain yield/plant was significantly reduced (17.44 g to 13.25 g) under drought. The principal components based on eigenvalue indicated significant PCs (first-seven) accounted for 79.9% and 73.9% of total variability under normal irrigation and drought, respectively. The investigated yield traits showed complex genetic behaviour. The genetic advance confronted a moderate to high heritability for spikelets/spike and grain yield/plant. The traits conditioned by dominant genetic effects in normal irrigation were inversely controlled by additive genetic effects under drought and vice versa. The magnitude of dominance effects for phenological and yield traits, i.e., leaf twist, auricle hairiness, grain yield/plant, spikelets, and grains/spike suggests that selection by the pedigree method is appropriate for improving these traits under normal irrigation conditions and could serve as an indirect selection index for improving yield-oriented traits in wheat populations for drought tolerance. However, the phenotypic selection could be more than effective for traits conditioned by additive genetic effects under drought. We suggest five significant cross combinations based on heterotic and heterobeltiotic potential of wheat genotypes for improved yield and enhanced biological production of wheat in advanced generations under drought.     

Biosynthesis of selenocysteine on its tRNA in eukaryotes

Selenocysteine (Sec) is cotranslationally inserted into protein in response to UGA codons and is the 21st amino acid in the genetic code. However, the means by which Sec is synthesized in eukaryotes is not known. Herein, comparative genomics and experimental analyses revealed that the mammalian Sec synthase (SecS) is the previously identified pyridoxal phosphate-containing protein known as the soluble liver antigen. SecS required selenophosphate and O-phosphoseryl-tRNA^[Ser]Sec as substrates to generate selenocysteyl-tRNA^[Ser]Sec. Moreover, it was found that Sec was synthesized on the tRNA scaffold from selenide, ATP, and serine using tRNA^[Ser]Sec, seryl-tRNA synthetase, O-phosphoseryl-tRNA^[Ser]Sec kinase, selenophosphate synthetase, and SecS. By identifying the pathway of Sec biosynthesis in mammals, this study not only functionally characterized SecS but also assigned the function of the O-phosphoseryl-tRNA^[Ser]Sec kinase. In addition, we found that selenophosphate synthetase 2 could synthesize monoselenophosphate in vitro but selenophosphate synthetase 1 could not. Conservation of the overall pathway of Sec biosynthesis suggests that this pathway is also active in other eukaryotes and archaea that synthesize selenoproteins.