A honey bee digestive phospholipase A2: Presenting and writing on an international stage

David Stanley,Yi-yun Xu 한국응용곤충학회 2018 한국응용곤충학회 학술대회논문집 Vol.2018 No.04

Honey bees are challenged with declining colony numbers, generally called ‘Colony Collapse Syndrome’ (CCS). This issue is certainly a syndrome because it is due to a range of threats, including parasitic mites, exposure to agricultural chemicals and various viruses, among other things. We posed the hypothesis the CCS could also be due to declining nutritional qualities, which may relate to digestive physiology. Because there is no information on honey bee lipid nutrition and digestion, we characterized a digestive phospholipase A2 in honey bee midguts. In this paper, I will report on some of our findings. With a focus on students, I will also use this report to share thoughts on presenting and writing for international audiences.

Eicosanoid Signaling in Insects: from Discovery to Plant Protection

Stanley, David,Kim, Yonggyun Taylor Francis 2014 Critical reviews in plant sciences Vol.33 No.1

Inhibition of a NEDD8 Cascade Restores Restriction of HIV by APOBEC3G

( David J Stanley ),( Koen Bartholomeeusen ),( David C Crosby ),( Dong Yong Kim ),( Eunju Kwon ),( Linda Yen ),( Nathalie Caretta Cartazo ),( Ming Li ),( Stefanie J?ger ),( Jeremy Mason Herr ),( Fumia 영남대학교 약품개발연구소 2013 영남대학교 약품개발연구소 연구업적집 Vol.23 No.0

Cellular restriction factors help to defend humans against human immunodeficiency virus (HIV). HIV accessory proteins hijack at least three different Cullin-RING ubiquitin ligases, which must be activated by the small ubiquitin-like protein NEDD8, in order to counteract host cellularrestriction factors. We found that conjugation of NEDD8 to Cullin-5 by the NEDD8-conjugating enzyme UBE2F is required for HIV Vif-mediated degradation of the host restriction factor APOBEC3G (A3G). Pharmacological inhibition of the NEDD8 E1 by MLN4924 or knockdown of either UBE2F or its RING-protein binding partner RBX2 bypasses the effect of Vif, restoring the restriction of HIV by A3G. NMR mapping and mutational analyses define specificity determinants of the UBE2F NEDD8 cascade. These studies demonstrate that disrupting host NEDD8 cascades presents a novel antiretroviral therapeutic approach enhancing the ability of the immune system to combat HIV.

Physiological trade-off between cellular immunity and flight capability in the wing-dimorphic sand cricket, Gryllus firmus

박영진,David Stanley 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.3

The sand cricket, Gryllus firmus, is a wing-dimorphic species with long-wing (LW) and shortwing (LW) morphs. The LWforms have very well developedwings and flight muscles and their SWcounterparts have reducedwings and flight muscles, coupled with greater resource allocations to reproduction. This is thewell-known oogenesisflight syndrome, inwhich resources are differentially allocated to reproduction or flight. Insects have also evolved very sophisticated and robust immune systems, understood as a major adaptation that partly accounts for the long-term biological success of insects. Nodulation is the predominant cellular immune reaction to microbial infections, responsible for clearingmost infecting microbes fromhemolymph circulation in the first two hours after an infection. This is a biologically expensive process because in large infections millions of hemocytes are invested into melanotic nodules. These lost hemocytes are later replaced in hematopoietic organs. Honey bees and a few other insect species redirect resources fromcellular immunity to another biologically expensive activity, foraging flights. These reallocations are conceived as physiological trade-offs, inwhich the costs of one biological function are traded off for another. Based on previous work, we posed the hypothesis that the sand cricket, Gryllus firmus, already known to reallocate resources in the oogenesis-flight syndrome, also reallocates resources from immune functions to flight. Here, we report that relative to long-wing morphs, the short-wing forms have higher immune capacity, registered in terms of nodulation reactions to the same challenge, higher hemocytic phospholipase A2 activity (an enzyme involved in immune signaling) and relatively reduced age-related immunosenescence. We infer from these data that sand crickets, and likely many insect species, reallocate resources between flight, reproduction and immunity. Such trade-offsmay support other functions, such as foraging and mate finding, as well.

Cellular immunosenescence in adult male crickets, <i>Gryllus assimilis</i>

Park, Youngjin,Kim, Yonggyun,Stanley, David Wiley Subscription Services, Inc., A Wiley Company 2011 Archives of Insect Biochemistry and Physiology Vol.76 No.4

<P><B>Abstract</B></P><P>Ecological immunity studies in invertebrates, particularly insects, have generated new insights into trade‐offs between immune functions and other physiological parameters. These studies document physiologically directed reallocations of immune costs to other high‐cost areas of physiology. Immunosenescence, recognized as the age‐related deterioration of immune functions, is another mechanism of radically altering immune systems. We investigated the hypothesis that aging brings on immunosenescence in adult males of the cricket, <I>Gryllus assimilis.</I> Our data show that the intensity of melanotic nodule formation decreased with adult age from after 3‐week post‐adult emergence. Circulating hemocyte populations similarly decreased from about 5,000 hemocytes/<I>µ</I>l hemolymph to about 1,000 hemocytes/<I>µ</I>l hemolymph. The numbers of damaged hemocytes in circulation increased from less than 10% at 1‐week post‐adult emergence to approximately 60% by 3‐week post‐adult emergence. The composition of hemocyte types changed with age, with increasing proportions of granulocytes and decreasing proportions of plasmatocytes. The declines in nodule formation were not linked to the adult age of sexual behaviors, which begin shortly after entering adulthood in this species. We infer that age‐related senescence, rather than cost reallocations, may account for observed declines in various parameters of immune functions in insects, as seen in other animals. © 2011 Wiley Periodicals, Inc.</P>

Plasmatocyte‐spreading peptide influences hemocyte behavior via eicosanoids

Srikanth, Koigoora,Park, Junga,Stanley, David W.,Kim, Yonggyun Wiley Subscription Services, Inc., A Wiley Company 2011 Archives of Insect Biochemistry and Physiology Vol.78 No.3

<P><B>Abstract</B></P><P>Hemocyte‐spreading behavior is required for expressing a cellular immune response, nodulation, which clears the vast majority of invading microbes from circulation. The nodulation response is completed by a layer of plasmatocytes, which spread over the nodule and initiate a malanization process leading to darkened nodules. Plasmatocyte‐spreading peptide (PSP), the first reported insect cytokine, is responsible for mediating the spreading and attachment of some subclasses of plasmatocytes to nodules. Prostaglandins (PGs), one group of eicosanoids formed from arachidonic acid (AA), also mediate plasmatocyte spreading (PS), although the potential interactions between the PSP and PG signal transduction pathways have not been investigated. We tested our hypothesis that PSP acts via biosynthesis of eicosanoids, specifically PGs, in the beet armyworm, <I>Spodoptera exigua</I>. In this study, we report that (1) PSP and PGE<SUB>2</SUB> independently stimulated Ca<SUP>++</SUP>‐dependent PS, (2) inhibitors of PG biosynthesis reversibly blocked PS, (3) dsRNA silencing the gene encoding proPSP blocked PS, which was rescued by PSP and by AA, (4) PSP‐stimulated PS was reversibly impaired by inhibitors of PG biosynthesis, and (5) the inhibitor‐impaired spreading was rescued by AA. Taken together, these points strongly support our model showing that PSP acts via a plasmatocyte‐surface receptor, which stimulates biosynthesis of the PGs responsible for mediating plasmatocytes spreading. © 2011 Wiley Periodicals, Inc.</P>

Eicosanoid-mediated immunity in insects

Kim, Yonggyun,Ahmed, Shabbir,Stanley, David,An, Chunju PERGAMON 2018 DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Vol. No.

<P><B>Abstract</B></P> <P>Eicosanoid is a collective term for oxygenated metabolites of C20 polyunsaturated fatty acids. As seen in mammals, eicosanoids play crucial roles in mediating various physiological processes, including immune responses, in insects. Upon microbial pathogen infection, non-self recognition signals are propagated to nearly immune effectors such as hemocytes and fat body using various immune mediators, in which eicosanoid signals act as the ultimate downstream mediator. The chemical diversity of eicosanoids may operate to mediate various immune responses. Some entomopathogenic bacteria suppress eicosanoid biosynthesis, which inhibits host insect immunity and promotes their pathogenicity. This review introduces immune responses mediated by various eicosanoids. Then it explains the cross-talks of eicosanoids with other immune mediators including cytokines, biogenic monoamines, and nitric oxide to clarify the complexity of insect immune mediation. Finally, we highlight the biological significance of eicosanoids by demonstrating bacterial pathogenicity inhibiting a key enzyme – phospholipase A<SUB>2</SUB> – in eicosanoid biosynthesis using their secondary metabolites to defend host insect immune attack.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Eicosanoids play crucial roles in mediating insect immune responses. </LI> <LI> Eicosanoid signals act as the ultimate downstream mediator. </LI> <LI> Some insect pathogens suppress insect immunity by inhibiting eicosanoid biosynthesis. </LI> </UL> </P>

Nucleation and Aggregative Growth of Palladium Nanoparticles on Carbon Electrodes: Experiment and Kinetic Model

Kim, Yang-Rae,Lai, Stanley C. S.,McKelvey, Kim,Zhang, Guohui,Perry, David,Miller, Thomas S.,Unwin, Patrick R. American Chemical Society 2015 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.119 No.30

<P>The mechanism and kinetics of the electrochemical nucleation and growth of palladium (Pd) nanoparticles (NPs) on carbon electrodes have been investigated using a microscale meniscus cell on both highly oriented pyrolytic graphite (HOPG) and a carbon-coated transmission electron microscopy (TEM) grid. Using a microscale meniscus cell, it is possible to monitor the initial stage of electrodeposition electrochemically, while the ability to measure directly on a TEM grid allows subsequent high-resolution microscopy characterization which provides detailed nanoscopic and kinetic information. TEM analysis clearly shows that Pd is electrodeposited in the form of NPs (approximately 1–2 nm diameter) that aggregate into extensive nanocrystal-type structures. This gives rise to a high NP density. This mechanism is shown to be consistent with double potential step chronoamperometry measurements on HOPG, where a forward step generates electrodeposited Pd and the reverse step oxidizes the surface of the electrodeposited Pd to Pd oxide. The charge passed in these transients can be used to estimate the amounts of NPs electrodeposited and their size. Good agreement is found between the electrochemically determined parameters and the microscopy measurements. A model for electrodeposition based on the nucleation of NPs that aggregate to form stable structures is proposed that is used to analyze data and extract kinetics. This simple model reveals considerable information on the NP nucleation rate, the importance of aggregation in the deposition process, and quantitative values for the aggregation rate.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-30/acs.jpcc.5b03513/production/images/medium/jp-2015-03513y_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5b03513'>ACS Electronic Supporting Info</A></P>

Neural Network-Based System Identification and Controller Synthesis for an Industrial Sewing Machine

Il-Hwan Kim,Stanley Fok,Kingsley Fregene,Dong-Hoon Lee,Tae-Seok Oh,David W. L. Wang 대한전기학회 2004 International Journal of Control, Automation, and Vol.2 No.1

The Monoterpenoid Produced by Entomopathogenic Bacterium, Xenorhabdus nematophilus, Inhibits Phospholipase A2 Activity

Park Young-Jin,Putnam Sean M.,Kim Yong-Gyun,Stanley David W. 한국응용곤충학회 2003 한국응용곤충학회 학술대회논문집 Vol.2003 No.1