Imaging, pathology, and diagnosis of solitary fibrous tumor of the pancreas: A case report and review of literature.

BACKGROUND: A solitary fibrous tumor (SFT) is often located in the pleura, while SFT of the pancreas is extremely rare. Here, we report a case of SFT of the pancreas and discuss imaging, histopathology, and immunohistochemistry for accurate diagnosis and treatment. CASE SUMMARY: A 54-year-old man presented to our hospital with pancreatic occupancy for over a month. There were no previous complaints of discomfort. His blood pressure was normal. Blood glucose, tumor markers, and enhanced computed tomography (CT) suggested a malignant tumor. Because the CT appearance of pancreatic cancer varies, we could not confirm the diagnosis; therefore, we performed endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB). Pathology and immunohistochemistry were consistent with SFT of the pancreas. The postoperative pathology and immunohistochemistry were consistent with the puncture results. The patient presented for a follow-up examination one month after discharge with no adverse effects. CONCLUSION: Other diseases must be excluded in patients with a pancreatic mass that cannot be diagnosed. CT and pathological histology have diagnostic value for pancreatic tumors. Endoscopic puncture biopsy under ultrasound can help diagnose pancreatic masses that cannot be diagnosed preoperatively. Surgery is an effective treatment for SFT of the pancreas; however, long-term follow-up is strongly recommended because of the possibility of malignant transformation of the tumor.

Metabolomic Analysis of Cricket paralysisvirus Infection in Drosophila S2 Cells Reveals Divergent Effects on Central Carbon Metabolism as Compared with Silkworm Bm5 Cells.

High-throughput approaches have opened new opportunities for understanding biological processes such as persistent virus infections, which are widespread. However, the potential of persistent infections to develop towards pathogenesis remains to be investigated, particularly with respect to the role of host metabolism. To explore the interactions between cellular metabolism and persistent/pathogenic virus infection, we performed untargeted and targeted metabolomic analysis to examine the effects of Cricket paralysis virus (CrPV, Dicistroviridae) in persistently infected silkworm Bm5 cells and acutely infected Drosophila S2 cells. Our previous study (Viruses 2019, 11, 861) established that both glucose and glutamine levels significantly increased during the persistent period of CrPV infection of Bm5 cells, while they decreased steeply during the pathogenic stages. Strikingly, in this study, an almost opposite pattern in change of metabolites was observed during different stages of acute infection of S2 cells. More specifically, a significant decrease in amino acids and carbohydrates was observed prior to pathogenesis, while their abundance significantly increased again during pathogenesis. Our study illustrates the occurrence of diametrically opposite changes in central carbon mechanisms during CrPV infection of S2 and Bm5 cells that is possibly related to the type of infection (acute or persistent) that is triggered by the virus.

Divergent molecular evolution in glutathione S-transferase conferring malathion resistance in the oriental fruit fly, Bactrocera dorsalis (Hendel).

Insect glutathione S-transferases (GSTs) are important in insecticide detoxification and Insect-specific GSTs, Epsilon and Delta, have largely expanded in insects. In this study, we functionally expressed and characterized an epsilon class GST gene (BdGSTe8), predominant in the adult Malpighian tubules of Bactrocera dorsalis. This gene may be associated with malathion resistance based on transcriptional studies of resistant and susceptible strains. RNA interference-mediated knockdown of this gene significantly recovered malathion susceptibility in the adults of a malathion-resistant strain, and overexpression of BdGSTe8 enhanced resistance in transgenic Drosophila. Analysis of BdGSTe8 polymorphism showed that several point mutations may be associated with metabolic resistance to malathion. A cytotoxicity assay in Escherichia coli indicated that both of the recombinant BdGSTe8 proteins may play a functional role in protecting cells from toxicity. The allele of BdGSTe8-B conferred higher levels of malathion detoxification capability. Liquid chromatography and ultra-performance liquid chromatography-tandem mass spectrometry analysis showed that the BdGSTe8-A allele did not metabolize malathion directly. However, the BdGSTe8-B allele was involved in the direct metabolism of malathion, which was caused by a mutation in V128A. Further analysis of the sequence suggests that BdGSTe8 evolved rapidly. It maybe play the role of a backup gene and could become a new gene in the future in order to retain the ability of detoxification of malathion, which was driven by positive selection. These results suggest that divergent molecular evolution in BdGSTe8 has played a role in metabolic resistance to malathion in B. dorsalis.

A Metabolomics Approach to Unravel Cricket Paralysis Virus Infection in Silkworm Bm5 Cells.

How a host metabolism responds to infection with insect viruses and how it relates to pathogenesis, is little investigated. Our previous study observed that Cricket paralysis virus (CrPV, Dicistroviridae) causes short term persistence in silkworm Bm5 cells before proceeding to acute infection. In this study, a metabolomics approach based on high resolution mass spectrometry was applied to investigate how a host metabolism is altered during the course of CrPV infection in Bm5 cells and which changes are characteristic for the transition from persistence to pathogenicity. We observed that CrPV infection led to significant and stage-specific metabolic changes in Bm5 cells. Differential metabolites abundance and pathway analysis further identified specific metabolic features at different stages in the viral life cycle. Notably, both glucose and glutamine levels significantly increased during CrPV persistent infection followed by a steep decrease during the pathogenic stages, suggesting that the central carbon metabolism was significantly modified during CrPV infection in Bm5 cells. In addition, dynamic changes in levels of polyamines were detected. Taken together, this study characterized for the first time the metabolic dynamics of CrPV infection in insect cells, proposing a central role for the regulation of both amino acid and carbohydrate metabolism during the period of persistent infection of CrPV in Bm5 cells.

Functional characterization of BdB1, a well-conserved carboxylesterase among tephritid fruit flies associated with malathion resistance in Bactrocera dorsalis (Hendel).

There are many evidences that insect carboxylesterase possess important physiological roles in xenobiotic metabolism and are implicated in the detoxification of organophosphate (OP) insecticides. Despite the ongoing resistance development in the oriental fruit fly, Bactrocera dorsalis (Hendel), the molecular basis of carboxylesterase and its ability to confer OP resistance remain largely obscure. This study was initiated to provide a better understanding of carboxylesterase-mediated resistance mechanism in a tephritid pest fly. Here, we narrow this research gap by demonstrating a well-conserved esterase B1 gene, BdB1, mediates malathion resistance development via gene upregulation with the use of a laboratory selected malathion-resistant strain (MR) of B. dorsalis. No sequence mutation of BdB1 was detected between MR and the susceptible strain (MS) of B. dorsalis. BdB1 is predominantly expressed in the midgut, a key insect tissue for detoxification. As compared with transcripts in MS, BdB1 was significantly more abundant in multiple tissues in the MR. RNA interference (RNAi)-mediated knockdown of BdB1 significantly increased malathion susceptibility. Furthermore, heterologous expression along with cytotoxicity assay revealed BdB1 could probably have the function of malathion detoxification.

Functional characterization of an α-esterase gene involving malathion detoxification in Bactrocera dorsalis (Hendel).

Extensive use of insecticides in many orchards has prompted resistance development in the oriental fruit fly, Bactrocera dorsalis (Hendel). In this study, a laboratory selected strain of B. dorsalis (MR) with a 21-fold higher resistance to malathion was used to examine the resistance mechanisms to this organophosphate insecticide. Carboxylesterase (CarE) was found to be involved in malathion resistance in B. dorsalis from the synergism bioassay by CarE-specific inhibitor triphenylphosphate (TPP). Molecular studies further identified a previously uncharacterized α-esterase gene, BdCarE2, that may function in the development of malathion resistance in B. dorsalis via gene upregulation. This gene is predominantly expressed in the Malpighian tubules, a key insect tissue for detoxification. The transcript levels of BdCarE2 were also compared between the MR and a malathion-susceptible (MS) strain of B. dorsalis, and it was significantly more abundant in the MR strain. No sequence mutation or gene copy changes were detected between the two strains. Functional studies using RNA interference (RNAi)-mediated knockdown of BdCarE2 significantly increased the malathion susceptibility in the adult files. Furthermore, heterologous expression of BdCarE2 combined with cytotoxicity assay in Sf9 cells demonstrated that BdCarE2 could probably detoxify malathion. Taken together, the current study bring new molecular evidence supporting the involvement of CarE-mediated metabolism in resistance development against malathion in B. dorsalis and also provide bases on functional analysis of insect α-esterase associated with insecticide resistance.

Inheritance, Realized Heritability, and Biochemical Mechanisms of Malathion Resistance in Bactrocera dorsalis (Diptera: Tephritidae).

To better characterize the resistance development and therefore establish effective pest management strategies, this study was undertaken to investigate the inheritance mode and biochemical mechanisms of malathion resistance in the oriental fruit fly, Bactrocera dorsalis (Hendel), which is one of the most notorious pests in the world. After 22 generations of selection with malathion, the malathion-resistant (MR) strain of B. dorsalis developed a 34-fold resistance compared with a laboratory susceptible strain [malathion-susceptible (MS)]. Bioassay results showed that there was no significant difference between the LD50 values of malathion against the progenies from both reciprocal crosses (F(1)-SR and F(1)-RS). The degree of dominance values (D) was calculated as 0.39 and 0.32 for F(1)-RS and F(1)-SR, respectively. The logarithm dosage-probit mortality lines of the F(2) generation and progeny from the backcross showed no clear plateaus of mortality across a range of doses. In addition, Chi-square analysis revealed significant differences between the mortality data and the theoretical expectations. The realized heritability (h(2)) value was 0.16 in the laboratory-selected resistant strain of B. dorsalis. Enzymatic activities identified significant changes of carboxylesterases, cytochrome P450 (general oxidases), and glutathione S-transferases in MR compared with the MS strain of B. dorsalis. Taken together, this study revealed for the first time that malathion resistance in B. dorsalis follows an autosomal, incompletely dominant, and polygenic mode of inheritance and is closely associated with significantly elevated activities of three major detoxification enzymes.

The epsilon glutathione S-transferases contribute to the malathion resistance in the oriental fruit fly, Bactrocera dorsalis (Hendel).

Epsilon glutathione S-transferases (eGSTs) play important roles in xenobiotics detoxification and insecticides resistance in insects. However, the molecular mechanisms of eGSTs-mediated insecticide resistance remain largely unknown in the Bactrocera dorsalis (Hendel), one of the most notorious pests in the world. Here, we investigated the roles of eight GST genes which belonged to epsilon class (BdGSTe1, BdGSTe2, BdGSTe3, BdGSTe4, BdGSTe5, BdGSTe6, BdGSTe7 and BdGSTe9) in conferring malathion resistance in B. dorsalis. Adult developmental stage-, sex- and tissue-specific expression patterns of the eight eGST genes were analyzed via quantitative reverse transcription PCR. The results showed that BdGSTe2, BdGSTe3, BdGSTe4 and BdGSTe9 were abundant in the midgut, fat body and Malpighian tubules. Notably, BdGSTe2, BdGSTe4 and BdGSTe9 were significantly overexpressed in a malathion-resistant (MR) strain of B. dorsalis compared to the malathion-susceptible (MS) strain. Functional expression and cytotoxicity assays showed significantly higher malathion detoxification capabilities in BdGSTe2-, BdGSTe3-, BdGSTe4- and BdGSTe9-expressing Sf9 cells compared to the parental and green fluorescent protein (GFP)-expressing Sf9 cells. Moreover, malathion susceptibility in MS adults was increased 30%, 14%, and 33% when BdGSTe2, BdGSTe3 and BdGSTe4 mRNA levels were repressed by RNA interference (RNAi)-mediated knockdown, respectively. Taken together, overexpression of the isoforms of eGSTs, including BdGSTe2, BdGSTe4, and particularly, BdGSTe9 plays an important role in the malathion resistant development in B. dorsalis.

Functional characterization of NADPH-cytochrome P450 reductase from Bactrocera dorsalis: Possible involvement in susceptibility to malathion.

NADPH cytochrome P450 reductase (CPR) is essential for cytochrome P450 catalysis, which is important in the detoxification and activation of xenobiotics. In this study, two transcripts of Bactrocera dorsalis CPR (BdCPR) were cloned, and the deduced amino-acid sequence had an N-terminus membrane anchor for BdCPR-X1 and three conserved binding domains (FMN, FAD, and NADP), as well as an FAD binding motif and catalytic residues for both BdCPR-X1 and BdCPR-X2. BdCPR-X1 was detected to have the high expression levels in adults and in Malpighian tubules, fat bodies, and midguts of adults, but BdCPR-X2 expressed lowly in B. dorsalis. The levels of BdCPRs were similar in malathion-resistant strain compared to susceptible strain. However, injecting adults with double-stranded RNA against BdCPR significantly reduced the transcript levels of the mRNA, and knockdown of BdCPR increased adult susceptibility to malathion. Expressing complete BdCPR-X1 cDNA in Sf9 cells resulted in high activity determined by cytochrome c reduction and these cells had higher viability after exposure to malathion than control. The results suggest that BdCPR could affect the susceptibility of B. dorsalis to malathion and eukaryotic expression of BdCPR would lay a solid foundation for further investigation of P450 in B. dorsalis.