Identification of reference markers for characterizing honey bee (Apis mellifera) hemocyte classes

Cell mediated immunity of the honey bee (Apis mellifera) involves the activity of several hemocyte populations, currently defined by morphological features and lectin binding characteristics. The objective of the present study was to identify molecular markers capable of characterizing subsets of honey bee hemocytes. We developed and employed monoclonal antibodies with restricted reactions to functionally distinct hemocyte subpopulations. Melanizing cells, known as oenocytoids, were defined by an antibody to prophenoloxidase, aggregating cells were identified by the expression of Hemolectin, and phagocytic cells were identified by a marker expressed on granulocytes. We anticipate that this combination of antibodies not only allows for the detection of functionally distinct hemocyte subtypes, but will help to further the exploration of hematopoietic compartments, as well as reveal details of the honey bee cellular immune defense against parasites and microbes

Analysis of Ras-induced overproliferation in Drosophila hemocytes.

We use the Drosophila melanogaster larval hematopoietic system as an in vivo model for the genetic and functional genomic analysis of oncogenic cell overproliferation. Ras regulates cell proliferation and differentiation in multicellular eukaryotes. To further elucidate the role of activated Ras in cell overproliferation, we generated a collagen promoter-Gal4 strain to overexpress Ras(V12) in Drosophila hemocytes. Activated Ras causes a dramatic increase in the number of circulating larval hemocytes (blood cells), which is caused by cellular overproliferation. This phenotype is mediated by the Raf/MAPK pathway. The mutant hemocytes retain the ability to phagocytose bacteria as well as to differentiate into lamellocytes. Microarray analysis of hemocytes overexpressing Ras(V12) vs. Ras(+) identified 279 transcripts that are differentially expressed threefold or more in hemocytes expressing activated Ras. This work demonstrates that it will be feasible to combine genetic and functional genomic approaches in the Drosophila hematopoietic system to systematically identify oncogene-specific downstream targets

Activation of the Drosophila NF-κB factor Relish by rapid endoproteolytic cleavage

The Rel/NF-κB transcription factor Relish plays a key role in the humoral immune response in Drosophila. We now find that activation of this innate immune response is preceded by rapid proteolytic cleavage of Relish into two parts. An N-terminal fragment, containing the DNA-binding Rel homology domain, translocates to the nucleus where it binds to the promoter of the Cecropin A1 gene and probably to the promoters of other antimicrobial peptide genes. The C-terminal IκB-like fragment remains in the cytoplasm. This endoproteolytic cleavage does not involve the proteasome, requires the DREDD caspase, and is different from previously described mechanisms for Rel factor activation

Regression plane concept for analysing continuous cellular processes with machine learning

Biological processes are inherently continuous, and the chance of phenotypic discovery is significantly restricted by discretising them. Using multi-parametric active regression we introduce the Regression Plane (RP), a user-friendly discovery tool enabling class-free phenotypic supervised machine learning, to describe and explore biological data in a continuous manner. First, we compare traditional classification with regression in a simulated experimental setup. Second, we use our framework to identify genes involved in regulating triglyceride levels in human cells. Subsequently, we analyse a time-lapse dataset on mitosis to demonstrate that the proposed methodology is capable of modelling complex processes at infinite resolution. Finally, we show that hemocyte differentiation in Drosophila melanogaster has continuous characteristics. High-content screening prompted the development of software enabling discrete phenotypic analysis of single cells. Here, the authors show that supervised continuous machine learning can drive novel discoveries in diverse imaging experiments and present the Regression Plane module of Advanced Cell Classifier.Peer reviewe

The raspberry Gene Is Involved in the Regulation of the Cellular Immune Response in Drosophila melanogaster

Drosophila is an extremely useful model organism for understanding how innate immune mechanisms defend against microbes and parasitoids. Large foreign objects trigger a potent cellular immune response in Drosophila larva. In the case of endoparasitoid wasp eggs, this response includes hemocyte proliferation, lamellocyte differentiation and eventual encapsulation of the egg. The encapsulation reaction involves the attachment and spreading of hemocytes around the egg, which requires cytoskeletal rearrangements, changes in adhesion properties and cell shape, as well as melanization of the capsule. Guanine nucleotide metabolism has an essential role in the regulation of pathways necessary for this encapsulation response. Here, we show that the Drosophila inosine 5'-monophosphate dehydrogenase (IMPDH), encoded by raspberry (ras), is centrally important for a proper cellular immune response against eggs from the parasitoid wasp Leptopilina boulardi. Notably, hemocyte attachment to the egg and subsequent melanization of the capsule are deficient in hypomorphic ras mutant larvae, which results in a compromised cellular immune response and increased survival of the parasitoid

Two Nimrod receptors, NimC1 and Eater, synergistically contribute to bacterial phagocytosis in Drosophila melanogaster

Eater and NimC1 are transmembrane receptors of the Drosophila Nimrod family, specifically expressed in haemocytes, the insect blood cells. Previous ex vivo and in vivoRNAi studies have pointed to their role in the phagocytosis of bacteria. Here, we have created a novel NimC1 null mutant to re-evaluate the role of NimC1, alone or in combination with Eater, in the cellular immune response. We show that NimC1 functions as an adhesion molecule ex vivo, but in contrast to Eater it is not required for haemocyte sessility in vivo. Ex vivo phagocytosis assays and electron microscopy experiments confirmed that Eater is the main phagocytic receptor for Gram-positive, but not Gram-negative bacteria, and contributes to microbe tethering to haemocytes. Surprisingly, NimC1 deletion did not impair phagocytosis of bacteria, nor their adhesion to the haemocytes. However, phagocytosis of both types of bacteria was almost abolished in NimC1(1);eater(1) haemocytes. This indicates that both receptors contribute synergistically to the phagocytosis of bacteria, but that Eater can bypass the requirement for NimC1. Finally, we uncovered that NimC1, but not Eater, is essential for uptake of latex beads and zymosan particles. We conclude that Eater and NimC1 are the two main receptors for phagocytosis of bacteria in Drosophila, and that each receptor likely plays distinct roles in microbial uptake

The Effect of Feeding with Central European Local Mulberry Genotypes on the Development and Health Status of Silkworms and Quality Parameters of Raw Silk

SIMPLE SUMMARY: Several regions of Slovenia and Hungary retained numerous centuries-old white mulberry trees, evidence of past sericultural activities, being traditionally used to feed the silkworm larvae. Attempts for the reintroduction of sericulture in these countries are ongoing. The current study assessed the suitability of the locally adapted mulberry trees for contemporary sericultural needs. Silkworm hybrids were fed with leaves of the selected local mulberry genotypes and the larvae performance parameters (bodyweight, spinning success, cocoon quantity, and quality) were compared to those fed with reference mulberry varieties. The chemical contents and nutritive parameters of the mulberry leaves were determined, and connections were predicted between selected leaf compounds and silkworm performance parameters. The local mulberries had higher total protein contents, and lower total phenolic contents and differed in some individual phenolics, macro- and microelements compared to the reference sericultural and fruit varieties. A combined positive influence of proteins, specific phenolics, and microelements on larval growth and silk thread parameters was predicted. The health status and gut microbiome compositions of larvae were also analyzed. The results of the study indicate that selected local Slovenian and Hungarian mulberry varieties are suitable for high-quality silk cocoon and raw silk production. ABSTRACT: Silkworm rearing activities ceased in the 1970′s in several European countries. Attempts on the re-establishment of ecological and sustainable sericulture in Slovenia and Hungary are ongoing. The aim of the study was to assess the usability of locally adapted mulberry genotypes for sericulture and to estimate connections between leaf compound and silkworm performance parameters. A controlled feeding experiment of silkworms was performed to test the influence of leaves from selected trees on the growth of larvae, the health and microbiological status of larvae (e.g., gut bacterial microbiome, Bombyx mori nucleopolyhedrovirus infection), weight of cocoons and raw silk parameters. The Slovenian and Hungarian mulberry genotypes had significantly higher total protein contents, and lower total phenolic contents and differed significantly in some individual phenolics compared to the reference sericultural and fruit varieties. Significant differences were found in the contents of the macro- and microelements, namely S, Mn, Fe, and Sr. Based on correlative statistics and multivariate analysis, a combined positive influence of proteins, specific phenolics, and microelements on larval growth and silk thread parameters was predicted. The results of the study indicate that selected local Slovenian and Hungarian mulberry varieties are suitable for high-quality silk cocoon and raw silk production

Synergistic inhibitory effect of apomine and lovastatin on osteosarcoma cell growth

BACKGROUND: Osteosarcoma is the most frequent malignant primary bone tumor that occurs mainly in the young, with an incidence peak observed at age 18 years. Both apomine and lovastatin have antitumor activity in a variety of cancer cell lines. Apomine, a 1,1-bisphosphonate-ester, increases the rate of degradation of 3-hydroxy-3 methylglutaryl-coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in the mevalonate pathway, whereas lovastatin competitively inhibits HMG-CoA reductase enzyme activity, thereby preventing protein prenylation and cholesterol synthesis. METHODS: The authors of this report investigated the effect of combined treatment with apomine and lovastatin in vitro on human and murine osteosarcoma cell lines and in vivo using a murine syngeneic model of osteosarcoma. Apomine and lovastatin synergistically decreased viability and induced apoptosis in both murine and human osteosarcoma cell lines. RESULTS: Combined apomine and lovastatin strongly decreased HMG-CoA reductase enzyme levels compared with lovastatin treatment alone. Consequently, the accumulation of unprenylated ras-related protein 1A induced by lovastatin was enhanced in the presence of apomine. All synergistic effects on cell viability, apoptosis, and protein prenylation were overcome by the addition of mevalonate or geranylgeraniol, 2 mevalonate pathway intermediates downstream from the target enzyme, HMG-CoA reductase. This confirmed that the mechanism of synergy in osteosarcoma cells is through augmented inhibition of HMG-CoA reductase. Finally, treatment of POS-1 osteosarcoma-bearing mice with a combination of apomine and lovastatin significantly reduced tumor progression in these mice compared with single treatments, which had no effect at the doses used. CONCLUSIONS: The results from this study revealed that combination therapy with apomine and lovastatin may be a novel treatment strategy for osteosarcoma. Cancer 2012;. © 2011 American Cancer Society