Molecular characterization of the carbon dioxide receptor in the oriental latrine fly, Chrysomya megacephala (Diptera: Calliphoridae).

The blowfly Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) cannot only act as a mechanical vector of various pathogens, but also infest man and animals causing human health problems and economic losses in the livestock and fish industries. As in other insects, olfaction of this species plays an important role in host location and is presumably mediated via transmembrane receptor signaling pathways. Here, we isolate and characterize CmegGr1 and CmegGr2, two new members of the chemosensory receptor gene family from C. megacephala. The open reading frames of CmegGr1 and CmegGr2 cDNA clones encode 453 and 486 amino acid residues, respectively. These two deduced proteins display high amino acid conservation with previously identified carbon dioxide (CO2) receptors, such as Drosophila melanogaster Gr21a/Gr63a and Anopheles gambiae s.s. Gr22/Gr24. Further sequence analysis showed that both proteins are consistent with their corresponding orthologs in the membrane topology prediction with some ambiguities in the location of N terminus and the number of transmembrane domains. The transcripts of CmegGr1 and CmegGr2 were detected in the major chemosensory organs including the antennae and proboscises with maxillary palps attached. These results suggest that CmegGr1 and CmegGr2 are likely to be the primary receptors for CO2 detection in C. megacephala. Knowledge of the molecular identity of the blowfly olfactory CO2 receptors may aid in the development of novel control strategies designed to take advantage of this unique and critical olfactory pathway.

Identification of forensically important arthropods on exposed remains during summer season in northeastern Egypt.

OBJECTIVE: To document the arthropod succession pattern and to identify forensically important species in northeastern Egypt (32° 15' E and 30° 36' N) for the first time. METHODS: Carcasses were exposed in an open area for 60 days during summer season. Ambient daily temperature (maximum and minimum) and relative humidity (RH) were recorded and existing keys were used for identification of different species. RESULTS: During the period of study, the mean of maximum and minimum temperatures were 34.85 °C and 29.2 °C respectively, while the mean of RH was 53.5%. Four stages of decomposition were observed: fresh, bloat, decay and dry. The most abundant orders were found to be Diptera, Coleoptera and Hymenoptera. Arthropods were collected belonging to 4 families of Diptera: Muscidae, Fanniidae, Calliphoridae and Sarcophagidae. While there were 2 families of Coleoptera: Dermestidae and Histeridae. Monomorium species was the only Hymenoptera family in this study. CONCLUSION: The present work provided a basis for further studies dealing with insect colonization of carcasses in different seasons and locations in Egypt.

Medical Morphology Training Using the Xuexi Tong Platform During the COVID-19 Pandemic: Development and Validation of a Web-Based Teaching Approach.

BACKGROUND: Histology and Embryology and Pathology are two important basic medical morphology courses for studying human histological structures under healthy and pathological conditions, respectively. There is a natural succession between the two courses. At the beginning of 2020, the COVID-19 pandemic suddenly swept the world. During this unusual period, to ensure that medical students would understand and master basic medical knowledge and to lay a solid foundation for future medical bridge courses and professional courses, a web-based medical morphology teaching team, mainly including teachers of courses in Histology and Embryology and Pathology, was established. OBJECTIVE: This study aimed to explore a new teaching mode of Histology and Embryology and Pathology courses during the COVID-19 pandemic and to illustrate its feasibility and acceptability. METHODS: From March to July 2020, our team selected clinical medicine undergraduate students who started their studies in 2018 and 2019 as recipients of web-based teaching. Meanwhile, nursing undergraduate students who started their studies in 2019 and 2020 were selected for traditional offline teaching as the control group. For the web-based teaching, our team used the Xuexi Tong platform as the major platform to realize a new "seven-in-one" teaching method (ie, videos, materials, chapter tests, interactions, homework, live broadcasts, and case analysis/discussion). This new teaching mode involved diverse web-based teaching methods and contents, including flipped classroom, screen-to-screen experimental teaching, a drawing competition, and a writing activity on the theme of "What I Know About COVID-19." When the teaching was about to end, a questionnaire was administered to obtain feedback regarding the teaching performance. In the meantime, the final written pathology examination results of the web-based teaching and traditional offline teaching groups were compared to examine the mastery of knowledge of the students. RESULTS: Using the Xuexi Tong platform as the major platform to conduct "seven-in-one" teaching is feasible and acceptable. With regard to the teaching performance of this new web-based teaching mode, students demonstrated a high degree of satisfaction, and the questionnaire showed that 71.3% or more of the students in different groups reported a greater degree of satisfaction or being very satisfied. In fact, more students achieved high scores (90-100) in the web-based learning group than in the offline learning control group (P=.02). Especially, the number of students with objective scores >60 in the web-based learning group was greater than that in the offline learning control group (P=.045). CONCLUSIONS: This study showed that the web-based teaching mode was not inferior to the traditional offline teaching mode for medical morphology courses, proving the feasibility and acceptability of web-based teaching during the COVID-19 pandemic. Our findings lay a solid theoretical foundation for follow-up studies of medical students.

Phylogenetic comparison and splice site conservation of eukaryotic U1 snRNP-specific U1-70K gene family.

Eukaryotic cells can expand their coding ability by using their splicing machinery, spliceosome, to process precursor mRNA (pre-mRNA) into mature messenger RNA. The mega-macromolecular spliceosome contains multiple subcomplexes, referred to as small nuclear ribonucleoproteins (snRNPs). Among these, U1 snRNP and its central component, U1-70K, are crucial for splice site recognition during early spliceosome assembly. The human U1-70K has been linked to several types of human autoimmune and neurodegenerative diseases. However, its phylogenetic relationship has been seldom reported. To this end, we carried out a systemic analysis of 95 animal U1-70K genes and compare these proteins to their yeast and plant counterparts. Analysis of their gene and protein structures, expression patterns and splicing conservation suggest that animal U1-70Ks are conserved in their molecular function, and may play essential role in cancers and juvenile development. In particular, animal U1-70Ks display unique characteristics of single copy number and a splicing isoform with truncated C-terminal, suggesting the specific role of these U1-70Ks in animal kingdom. In summary, our results provide phylogenetic overview of U1-70K gene family in vertebrates. In silico analyses conducted in this work will act as a reference for future functional studies of this crucial U1 splicing factor in animal kingdom.

MicroRNA-331 inhibits development of gastric cancer through targeting musashi1.

BACKGROUND: The molecular mechanisms involved in microRNAs (miRNAs) have been extensively investigated in gastric cancer (GC). However, how miR-331 regulates GC pathogenesis remains unknown. AIM: To illuminate the effect of miR-331 on cell metastasis and tumor growth in GC. METHODS: The qRT-PCR, CCK8, Transwell, cell adhesion, Western blot, luciferase reporter and xenograft tumor formation assays were applied to explore the regulatory mechanism of miR-331 in GC. RESULTS: Downregulation of miR-331 associated with poor prognosis was detected in GC. Functionally, miR-331 suppressed cell proliferation, metastasis and tumor growth in GC. Further, miR-331 was verified to directly target musashi1 (MSI1). In addition, miR-331 inversely regulated MSI1 expression in GC tissues. Furthermore, upregulation of MSI1 weakened the inhibitory effect of miR-331 in GC. CONCLUSION: miR-331 inhibited development of GC through targeting MSI1, which may be used as an indicator for the prediction and prognosis of GC.

The complete mitochondrial genome of the flesh fly, Boettcherisca peregrine (Diptera: Sarcophagidae).

The complete mitochondrial genome of Boettcherisca peregrine (B. peregrina), an important forensic entomology, was sequenced for the first time. The 14,922 bp circular genome contains 37 genes that were found in a typical Metazoan genome: 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. It also contains one non-coding A + T-rich region. The arrangement of the genes was the same as that found in the other insect. The overall base composition on heavy strand was as follows: A, 38.86%; G, 15.10%; C, 9.93%; T, 36.11%; and the A + T content 74.97%. The mitochondrial genome of Sarcophaga presented could be valuable for resolving phylogenetic relationships within the order Diptera and especially for the family Sarcophagidae. The molecular data presented may also be used to screen favorable molecular markers for species identifications for forensic entomology purposes.

The complete mitochondrial genome of the scuttle fly, Megaselia scalaris (Diptera: Phoridae).

More than 1400 scuttle flies species in worldwide comprise the Megaselia genus, the largest genus in the family Phoridae. The complete mitochondrial genome of Megaselia scalaris, a medically important entomology was sequenced for the first time. The 15,599 bp circular genome contains the 37 genes found in a typical Metazoan genome: 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. The mitochondrial genome also contains one non-coding A + T-rich region. The arrangement of the genes was identical with other insect. Each of the base composition on heavy strand was as follows A: 38.87%, G: 13.74%, C: 9.46%, T: 37.93% and the A + T content 76.80%. The mitochondrial genome of M. scalaris presented may be valuable for determining phylogenetic relationships within the order Diptera and especially for the family Phoridae. These sequences could also be used to select reliable molecular markers for species identification in forensic entomology.

Epidermal growth factor-like domain-containing protein 7 (EGFL7) enhances EGF receptor-AKT signaling, epithelial-mesenchymal transition, and metastasis of gastric cancer cells.

Epidermal growth factor-like domain-containing protein 7 (EGFL7) is upregulated in human epithelial tumors and so is a potential biomarker for malignancy. Indeed, previous studies have shown that high EGFL7 expression promotes infiltration and metastasis of gastric carcinoma. The epithelial-mesenchymal transition (EMT) initiates the metastatic cascade and endows cancer cells with invasive and migratory capacity; however, it is not known if EGFL7 promotes metastasis by triggering EMT. We found that EGFL7 was overexpressed in multiple human gastric cancer (GC) cell lines and that overexpression promoted cell invasion and migration as revealed by scratch wound and transwell migration assays. Conversely, shRNA-mediated EGFL7 knockdown reduced invasion and migration. Furthermore, EGFL7-overexpressing cells grew into larger tumors and were more likely to metastasize to the liver compared to underexpressing CG cells following subcutaneous injection in mice. EGFL7 overexpression protected GC cell lines against anoikis, providing a plausible mechanism for this enhanced metastatic capacity. In excised human gastric tumors, expression of EGFL7 was positively correlated with expression levels of the mesenchymal marker vimentin and the EMT-associated transcription repressor Snail, and negatively correlated with expression of the epithelial cell marker E-cadherin. In GC cell lines, EGFL7 knockdown reversed morphological signs of EMT and decreased both vimentin and Snail expression. In addition, EGFL7 overexpression promoted EGF receptor (EGFR) and protein kinase B (AKT) phospho-activation, effects markedly suppressed by the EGFR tyrosine kinase inhibitor AG1478. Moreover, AG1478 also reduced the elevated invasive and migratory capacity of GC cell lines overexpressing EGFL7. Collectively, these results strongly suggest that EGFL7 promotes metastasis by activating EMT through an EGFR-AKT-Snail signaling pathway. Disruption of EGFL7-EGFR-AKT-Snail signaling may a promising therapeutic strategy for gastric cancer.

Identification of forensically important sarcophagid flies (Diptera: Sarcophagidae) in China, based on COI and 16S rDNA gene sequences.

Insects attracted to cadavers may provide important indications of the postmortem interval (PMI). However, use of the flesh flies (Diptera: Sarcophagidae) for PMI estimation is limited as the species are often not morphologically distinct, especially as immatures. In this study, 23 forensically important flesh flies were collected from 13 locations in 10 Chinese provinces. Then, a 278-bp segment of the cytochrome oxidase subunits one (COI) gene and a 289-bp segment of the 16S rDNA gene of all specimens were successfully sequenced. Phylogenetic analysis of the sequenced segments showed that all sarcophagid specimens were properly assigned into four species (Boerttcherisca peregrina [Robineau-Desvoidy, 1830], Helicophagella melanura [Meigen, 1826], Parasarcophaga albiceps [Meigen, 1826], and Parasarcophaga dux [Thompson, 1869]) with relatively strong supporting values, thus indicating that the COI and 16S rDNA regions are suitable for identification of sarcophagid species. The difference between intraspecific threshold and interspecific divergence confirmed the potential of the two regions for sarcophagid species identification.