A comparative Proteomics Analysis Identified Differentially Expressed Proteins in Pancreatic Cancer–Associated Stellate Cell Small Extracellular Vesicles

Human pancreatic stellate cells (HPSCs) are an essential stromal component and mediators of pancreatic ductal adenocarcinoma (PDAC) progression. Small extracellular vesicles (sEVs) are membrane-enclosed nanoparticles involved in cell-to-cell communications and are released from stromal cells within PDAC. A detailed comparison of sEVs from normal pancreatic stellate cells (HPaStec) and from PDAC-associated stellate cells (HPSCs) remains a gap in our current knowledge regarding stellate cells and PDAC. We hypothesized there would be differences in sEVs secretion and protein expression that might contribute to PDAC biology. To test this hypothesis, we isolated sEVs using ultracentrifugation followed by characterization by electron microscopy and Nanoparticle Tracking Analysis. We report here our initial observations. First, HPSC cells derived from PDAC tumors secrete a higher volume of sEVs when compared to normal pancreatic stellate cells (HPaStec). Although our data revealed that both normal and tumor-derived sEVs demonstrated no significant biological effect on cancer cells, we observed efficient uptake of sEVs by both normal and cancer epithelial cells. Additionally, intact membrane-associated proteins on sEVs were essential for efficient uptake. We then compared sEV proteins isolated from HPSCs and HPaStecs cells using liquid chromatography–tandem mass spectrometry. Most of the 1481 protein groups identified were shared with the exosome database, ExoCarta. Eighty-seven protein groups were differentially expressed (selected by 2-fold difference and adjusted p value ≤0.05) between HPSC and HPaStec sEVs. Of note, HPSC sEVs contained dramatically more CSE1L (chromosome segregation 1–like protein), a described marker of poor prognosis in patients with pancreatic cancer. Based on our results, we have demonstrated unique populations of sEVs originating from stromal cells with PDAC and suggest that these are significant to cancer biology. Further studies should be undertaken to gain a deeper understanding that could drive novel therapy.     

An order-specific monoclonal antibody to Diptera reveals the impact of alternative prey on spider feeding behavior in a complex food web

Generalist predators have the capacity to restrict pest population growth, especially early in the season before densities increase. However, their polyphagous feeding habits sometimes translate into reduced pest consumption when they target alternative prey. An order-specific monoclonal antibody was developed to examine the strength of trophic connections between Diptera, a major category of non-pest prey, and linyphiid spiders in alfalfa. We report the development and characterization of a monoclonal antibody with order-level specificity to Diptera. This antibody elicited strong absorbance to 22 Diptera from 13 families, no false-positive reactivity to non-dipteran invertebrates, and antigen detection periods following prey consumption that were comparable between spiders. Over 900 field-collected females of the linyphiid spiders Erigone autumnalis and Bathyphantes pallidus were screened for Diptera antigen. Significantly more B. pallidus screened positive for Diptera (40%) compared to E. autumnalis (16%), indicating differential reliance on these prey. In parallel with the collection of spiders for gut-content analysis, prey availability was estimated at web sites. The two spiders exhibited different feeding responses to prey availability. Consumption of Diptera by B. pallidus was strongly correlated with Diptera abundance whilst the availability of other potential prey did not influence predation rates. Conversely, E. autumnalis did not prey upon Diptera in proportion to availability, but increased Collembola activity-density reduced dipteran consumption. Integration of molecular gut-content analysis with precise sampling of prey demonstrated how two closely related linyphiid spiders exhibit different feeding responses to the availability of prey under natural field conditions. Elucidating the feeding preferences of natural enemies is critical to effective incorporation of biological control by generalist predators in the management of agricultural pests.     

Water and solute transport by the Malpighian tubules of the stick insect,Carausius morosus

Summary Structural features of the principal, urine-secreting cells (type 1 cells) of the Malpighian tubules of Carausius are de scribedquantitatively and discussed in relation to possible mechanisms of water and solute transport. Mitochondria are arranged in two bands of about equal volume near to the basal and apical surfaces, suggesting active processes occur at both surfaces. Basal infoldings and apical microvilli which greatly amplify the cell surface are probably primarily devices to increase the passive permeability of the tissue to solutes. They do not provide functionally significant standing-osmotic-gradients. The extensive endoplasmic reticulum is locally differentiated into several components and ramifies between the infoldings and along microvilli but probably is not an intracellular conduit for the majority of urinary constituents. Vesicles and stages in their formation or liberation are observed both basally and apically although they probably do not contribute significantly to transcellular transport. At present it remains a problem to satisfactorily account for observations that the urine of Carausius can be hypotonic.This investigation formed part of a dissertation for the degree of Ph. D. in the University of Newcastle upon Tyne. It is a pleasure to thank Prof. J. Shaw for his advice and encouragement and the Science Research Council for financial support.     

Novel strategies for assessing and managing the risks posed by invasive alien species to global crop production and biodiversity

International actions to combat the threat posed by invasive alien species (IAS) to crops and biodiversity have intensified in recent years. The formulation of 15 guiding principles on IAS by the Convention on Biological Diversity (CBD) stimulated the International Plant Protection Convention (IPPC) to review its role in protecting biodiversity. IPPC standards now demonstrate clearly that the risks posed by any organism that is directly or indirectly injurious to cultivated or uncultivated plants can be assessed and managed under the IPPC. Since the IPPC, unlike the CBD, constitutes an international legal instrument recognised by the World Trade Organization, greater protection from the introduction of IAS is now available. However, phytosanitary measures can only be enacted if they can be justified by risk analysis and we outline some novel strategies to improve the assessment and management of the risks posed by IAS, highlighting some of the key challenges which remain.     

Impacts of a native parasitic plant on an introduced and a native host species: implications for the control of an invasive weed

Background and Aims: While invasive species may escape from natural enemies in thenew range, the establishment of novel biotic interactions withspecies native to the invaded range can determine their success.Biological control of plant populations can be achieved by manipulationof a species' enemies in the invaded range. Interactions weretherefore investigated between a native parasitic plant andan invasive legume in Mediterranean-type woodlands of SouthAustralia. Methods: The effects of the native stem parasite, Cassytha pubescens,on the introduced host, Cytisus scoparius, and a co-occurringnative host, Leptospermum myrsinoides, were compared. The hypothesisthat the parasitic plant would have a greater impact on theintroduced host than the native host was tested. In a fieldstudy, photosynthesis, growth and survival of hosts and parasitewere examined. Key Results: As predicted, Cassytha had greater impacts on the introducedhost than the native host. Dead Cytisus were associated withdense Cassytha infections but mortality of Leptospermum wasnot correlated with parasite infection. Cassytha infection reducedthe photosynthetic rates of both hosts. Infected Cytisus showedslower recovery of photosystem II efficiency, lower transpirationrates and reduced photosynthetic biomass in comparison withuninfected plants. Parasite photosynthetic rates and growthrates were higher when growing on the introduced host Cytisus,than on Leptospermum. Conclusions: Infection by a native parasitic plant had strong negative effectson the physiology and above-ground biomass allocation of anintroduced species and was correlated with increased plant mortality.The greater impact of the parasite on the introduced host maybe due to either the greater resources that this host providesor increased resistance to infection by the native host. Thisdisparity of effects between introduced host and native hostindicates the potential for Cassytha to be exploited as a controltool.     

Variation of Pleurotus ostreatus (Jacq. Ex Fr.) P. Kumm. (1871) performance subjected to differentdoses and timings of nano-urea

Supplementation of the growing substrate by nitrogenous additives has been known to improve the production of oyster mushroom (Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm. (1871)). However, the application of nano-additives has not been reported in such cultivation yet. The study investigated the effect of nano-urea added in two different doses (3 g and 5 g per kg substrate), once (at spawning or after first flush) or twice (at spawning and after first flush) to the growing substrate consisting of wheat straw and spent oyster substrate (1:1, w/w). Results showed that the application of nano-urea once has induced the highest number of mushroom flushes (four flushes) despite the dose applied. Contrarily to early findings, where high doses of nitrogen have caused inhibition of mushroom growth and production, nano-urea application has had better effects when applied twice. With 5 g/kg, it induced the shortest period between the first and the third flush (15 days). With 3 g/kg, it resulted in the highest biological and economic yields at the third flush (332.7 g/bag and 283.1 g/bag respectively), in total (973.4 g/bag and 854.0 g/bag respectively), the highest biological efficiency (109.6%), and pileus diameter/stipe length ratio (2.8). Experimental findings of the current study may be potentially applied at commercial scale.     

Suppression of pecan and peach pathogens on different substrates using Xenorhabdus bovienii and Photorhabdus luminescens

Prior research indicated the ability of concentrated metabolites from Xenorhabdus spp. and Photorhabdus spp. to suppress a variety of peach and pecan diseases in vitro, and on detached pecan leaves or terminals. In the current study, our objectives were to (1) determine if bacterial broths (in addition to concentrated metabolites tested previously) have suppressive ability and (2) determine if metabolites or bacterial broths are active in a soil medium. In laboratory studies, two pathogens of pecan (Fusicladium effusum and Phytophthora cactorum) and one peach pathogen (Armillaria tabescens) were tested for susceptibility to Xenorhabdus bovienii (SN) and Photorhabdus luminescens (VS) bacterial broths or concentrated metabolites on three different substrates. Treatments were applied to lesions of F. effusum on terminals to ascertain any suppressive effect on sporulation, to A. tabescens in soil to determine effect on survival of mycelia, and to lesions caused by P. cactorum on pecan leaf surfaces to assess any reduction in lesion development. Acetone (the metabolite solvent), un-inoculated media (tryptic soy broth) and water were included as controls. The X. bovienii metabolite treatment was as efficacious as a commercial fungicide (fenbuconazole) in reducing sporulation of F. effusum on pecan terminals. The P. luminescens metabolite treatment also caused reduced sporulation relative to water and acetone controls but bacterial broths had no effect. In contrast, all bacterial broth and metabolite treatments suppressed lesion growth caused by P. cactorum (measured on detached leaves maintained on agar). However, in soil, only the P. luminescens metabolite treatment was suppressive to A. tabescens (this is the first report of Photorhabdus or Xenorhabdus toxicity to Armillaria spp.). This study provides a basis for further research on the use of Xenorhabdus and Photorhabdus metabolites or bacterial broth for suppression of pecan and peach diseases.     

Biological rhythms in birds — development, insights and perspectives

The aim of this review is to show that probably the internal clock of precocial birds is imprinted in the prenatal period by exogenous factors (zeitgeber). The activity of organ functions occurs early during embryonic development, before this function is ultimately necessary to ensure the survival of the embryo. Prenatal activation of some functional systems may have a training effect on the postnatal efficiency.The development of physiological control systems is influenced by endogenous and exogenous factors during the late prenatal and early postnatal period: epigenetic adaptation processes play an important role in the development of animals; they have acquired characteristics which are innated but not genetically fixed. As a rule, the actual value during the determination period has a very strong influence on the set-point of the system. This will be explained using the example of thermoregulation.It is shown in detail that it seems to be possible to imprint the prenatal development of circadian rhythms by periodic changes of the light-dark cycle but not by rhythmic influence of acoustic signals.Altogether, there are more questions open than solved concerning the perinatal genesis of circadian rhythms in birds. Topics are given for the future research.     

Suppression of Plant-parasitic Nematode Populations in Turfgrass by Application of Entomopathogenic Nematodes

We studied the influence of entomopathogenic nematodes , Steinernema carpocapsae and S. riobravis, on natural populations of plant - parasitic nematodes (PPNs) infesting turfgrass in Georgia and South Carolina . S. riobravis applied at 6 109 infective juveniles (IJs) / acre provided up to 95 - 100% control of the root - knot , Meloidogyne sp ., sting , Belonolaimus longicaudatus, and ring nematode , Criconemella sp ., in Georgia , but S. carpocapsae had no effect . S. riobravis was as effective as the chemical nematicide , Fenamiphos (Nemacur 10G) at 4 weeks after treatment and more effective at 8 weeks after treatment . In South Carolina , both S. riobravis and S. carpocapsae applied at 1 109 IJs / acre provided up to 86 - 100 % control of the root - knot , sting and ring nematodes . Application of 6 109 IJs / acre increased control by only 4 - 14 % over the 1 109 dosage . Possible causes of differences in efficacy of S. carpocapsae at the two sites are discussed . It is concluded that S. riobravis may provide effective , predictable and economical control of PPNs in turfgrass .