scholarly journals The Alphavirus Sindbis Infects Enteroendocrine Cells in the Midgut of Aedes aegypti

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 848
Author(s):  
Yani P. Ahearn ◽  
Jason J. Saredy ◽  
Doria F. Bowers

Transit of the arthropod-borne-virus (arbovirus) Sindbis (SINV) throughout adult female mosquitoes initiates with its attachment to the gut lumen, entry and amplification in midgut cells, followed by dissemination into the hemolymph. Free-mated adult females, aged day 5–7, were proffered a viremic blood suspension via sausage casings containing SINV-TaV-Green Fluorescent Protein (GFP) at a final titer of 106 PFU/mL. Midguts (MGs) from fully engorged mosquitoes were resected on days 5 and 7 post-bloodmeal, and immunolabeled using FMRFamide antibody against enteroendocrine cells (ECs) with a TX-Red secondary antibody. Following immunolabeling, the organs were investigated via laser confocal microscopy to identify the distribution of GFP and TX-Red. Infection using this reporter virus was observed as multiple GFP expression foci along the posterior midgut (PMG) epithelium and ECs were observed as TX-Red labeled cells scattered along the entire length of the MG. Our results demonstrated that SINVGFP did infect ECs, as indicated by the overlapping GFP and TX-Red channels shown as yellow in merged images. We propose that ECs may be involved in the SINV infection pathway in the mosquito MG. Due to the unique role that ECs have in the exocytosis of secretory granules from the MG and the apical-basolateral position of ECs in the PMG monolayer, we speculate that these cells may assist as a mechanism for arboviruses to cross the gut barriers. These findings suggest that MG ECs are involved in arbovirus infection of the invertebrate host.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Danielle Weber-Adrian ◽  
Rikke Hahn Kofoed ◽  
Joseph Silburt ◽  
Zeinab Noroozian ◽  
Kairavi Shah ◽  
...  

AbstractNon-surgical gene delivery to the brain can be achieved following intravenous injection of viral vectors coupled with transcranial MRI-guided focused ultrasound (MRIgFUS) to temporarily and locally permeabilize the blood–brain barrier. Vector and promoter selection can provide neuronal expression in the brain, while limiting biodistribution and expression in peripheral organs. To date, the biodistribution of adeno-associated viruses (AAVs) within peripheral organs had not been quantified following intravenous injection and MRIgFUS delivery to the brain. We evaluated the quantity of viral DNA from the serotypes AAV9, AAV6, and a mosaic AAV1&2, expressing green fluorescent protein (GFP) under the neuron-specific synapsin promoter (syn). AAVs were administered intravenously during MRIgFUS targeting to the striatum and hippocampus in mice. The syn promoter led to undetectable levels of GFP expression in peripheral organs. In the liver, the biodistribution of AAV9 and AAV1&2 was 12.9- and 4.4-fold higher, respectively, compared to AAV6. The percentage of GFP-positive neurons in the FUS-targeted areas of the brain was comparable for AAV6-syn-GFP and AAV1&2-syn-GFP. In summary, MRIgFUS-mediated gene delivery with AAV6-syn-GFP had lower off-target biodistribution in the liver compared to AAV9 and AAV1&2, while providing neuronal GFP expression in the striatum and hippocampus.


2013 ◽  
Vol 95 (3) ◽  
pp. 319-329
Author(s):  
Atsushi Hirao ◽  
Tatsuo Kawarasaki ◽  
Kenjiro Konno ◽  
Satoko Enya ◽  
Masatoshi Shibata ◽  
...  

2020 ◽  
Vol 26 (2) ◽  
pp. 267-274
Author(s):  
Jason J. Saredy ◽  
Florence Y. Chim ◽  
Zoë L. Lyski ◽  
Yani P. Ahearn ◽  
Doria F. Bowers

AbstractBiological transmission of arthropod-borne viruses (arboviruses) to vertebrate hosts by hematophagous insects poses a global threat because such arboviruses can result in a range of serious public health infectious diseases. Sindbis virus (SINV), the prototype Alphavirus, was used to track infections in the posterior midgut (PMG) of Aedes aegypti adult mosquitoes. Females were fed viremic blood containing a virus reporter, SINV [Thosea asigna virus-green fluorescent protein (TaV-GFP)], that leaves a fluorescent signal in infected cells. We assessed whole-mount PMGs to identify primary foci, secondary target tissues, distribution, and virus persistence. Following a viremic blood meal, PMGs were dissected and analyzed at various days of post blood-feeding. We report that virus foci indicated by GFP in midgut epithelial cells resulted in a 9.8% PMG infection and a 10.8% dissemination from these infected guts. The number of virus foci ranged from 1 to 3 per individual PMG and was more prevalent in the PMG-middle > PMG-frontal > PMG-caudal regions. SINV TaV-GFP was first observed in the PMG (primary target tissue) at 3 days post blood-feeding, was sequestered in circumscribed foci, replicated in PMG peristaltic muscles (secondary target tissue) following dissemination, and GFP was observed to persist in PMGs for 30 days postinfection.


2018 ◽  
Vol 10 (4) ◽  
pp. 12
Author(s):  
Mahipal Singh ◽  
Xiaoling Ma

Dermal fibroblasts are useful for production of genetically engineered biologically active factors for development of cellular therapies and tissue engineering products for regenerative medicine. However, their transfection efficiencies using traditional non-viral methods are low and vary based on cell-type and species-specific differences. Using nucleofection technology, here we show that the transfection efficiency of primary fibroblasts established after 0-, 35-, and 65-days of postmortem storage of sheep skin tissues in a refrigerator was 59.49 % ± 9.66 %, 59.33 % ± 11.59 %, and 43.48 % ± 8.09 % respectively, as determined by analysis of green fluorescent protein (GFP) expression. 


2006 ◽  
Vol 18 (2) ◽  
pp. 297
Author(s):  
H. Y. Yong ◽  
C. Murphy ◽  
A. Rieke ◽  
L. Lai ◽  
Y. Hao ◽  
...  

The technique for intracytoplasmic sperm injection (ICSI) has, until now, focused on scoring the tail of the sperm prior to catching and aspiration into the injection pipette. This is in spite of the fact that damage to the head would more closely simulate what occurs during normal fertilization. In addition, to aid in visualizing the injection process so that a reduced volume can be injected, the oocyte is generally centrifuged to clear a portion of the cytoplasm. Thus, with conventional ICSI, the sperm are immobilized with polyvinylpyrrolidone, repeatedly frozen and thawed, treated with DTT or Triton X-100, and severed between the head and tail; the oocyte is centrifuged or activated. All of the above treatments are designed to compensate for the intrinsic defects in conventional ICSI. Our objective was to use a modified ICSI procedure whereby aggressively motile sperm were captured onto the broken tip of an injection pipette and then injected into noncentrifuged oocytes. Damage to the head of the sperm occurred on the pipette or while pushed through the zona pellucida. These procedures are based on the work of Yong et al. 2003 Hum. Reprod. 18, 2390, where they achieved an improvement in development in vitro as compared to conventional methods. Ovaries were collected from prepubertal gilts, and oocytes were aspirated and matured in vitro. Sperm were collected from a transgenic boar carrying the green fluorescent protein (GFP) and frozen. After thawing, aggressively motile sperm were captured and injected through the zona pellucida and into the cytoplasm of the in vitro-matured oocytes. A total of 452 injected oocytes (43-171 oocytes per recipient) were surgically transferred into the oviduct of six surrogate gilts. Two gilts (33%) became pregnant. One gave birth to a healthy male piglet. GFP expression was observed in the nose and hooves by direct epifluorescent examination of the newborn piglet. This pattern of GFP expression is identical to that in non-ICSI-derived GFP pigs in this line. This result showed for the first time that this new sperm injection technique could be used for production of a viable transgenic piglet using in vitro-matured oocytes and frozen-thawed sperm.


2020 ◽  
Author(s):  
Noriyuki Satoh ◽  
Koji Kinjo ◽  
Kohei Shintaku ◽  
Daisuke Kezuka ◽  
Hiroo Ishimori ◽  
...  

ABSTRACTCorals of the family Acroporidae are key structural components of reefs that support the most diverse marine ecosystems. Due to increasing anthropogenic stresses, coral reefs are in decline. Along the coast of Okinawa, Japan, three different color morphs of Acropora tenuis have been recognized for decades. These include brown (N morph), yellow-green (G) and purple (P) forms. The tips of axial coral polyps exhibit specific fluorescence spectra. This attribute is inherited asexually, and color morphs do not change seasonally. In Okinawa Prefecture, during the summer of 2017, the N and P morphs experienced bleaching, in which some N morphs died while P morphs recovered. In contrast, G morphs successfully withstood the stress. Symbiotic dinoflagellates are essential symbiotic partners of scleractinian corals. Photosynthetic activity of symbionts was reduced in July in N and P morphs; however, the three color-morphs host similar sets of Clade-C zoothanthellae, suggesting that beaching of N and P morphs cannot be attributed to differences in symbiont clades. The decoded Acropora tenuis genome includes five genes for green fluorescent proteins (GFP), two for cyan fluorescent proteins (CFP), three for red fluorescent proteins (RFP), and seven genes for chromoprotein (ChrP). A summer survey of gene expression profiles demonstrated that (a) expression of CFP and REP was quite low in all three morphs, (b) P morphs expressed higher levels of ChrP, (c) both N and G morphs expressed GFP highly, and (d) GFP expression was reduced in N morphs, compared to G morphs, which maintained higher levels of GFP expression throughout the summer. Although further studies are required to understand the biological significance of these color morphs of Acropora tenuis, our results suggest that thermal stress resistance is modified by genetic mechanisms that coincidentally lead to diversification of color morphs.


BioTechniques ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 91-95 ◽  
Author(s):  
Tomo Kondo ◽  
Shigehiko Yumura

During molecular cloning, screening bacterial transformants is a time-consuming and labor-intensive process; however, tractable tools that can be applied to various vectors for visual confirmation of desired colonies are limited. Recently, we reported that translational enhancement by a Dictyostelium gene sequence (TED) boosted protein expression even without an expression inducer in Escherichia coli. Here, we demonstrate a generally applicable molecular tool using the expression of green fluorescent protein enhanced by TED. By inserting a module related to TED into the cloning site in advance, we effectively screened E. coli colonies harboring the desired plasmid functions in a prokaryote ( Magnetospirillum gryphiswaldense) or eukaryote ( Dictyostelium discoideum). Thus, our system represents a user-friendly technique for cloning.


2006 ◽  
Vol 72 (9) ◽  
pp. 6088-6093 ◽  
Author(s):  
Helen Rawsthorne ◽  
Kevin N. Turner ◽  
David A. Mills

ABSTRACT Group II introns are mobile genetic elements that can be redirected to invade specific genes. Here we describe the use of the lactococcal group II intron, Ll.ltrB, to achieve multicopy delivery of heterologous genes into the genome of Lactococcus lactis IL1403-UCD without the need for selectable markers. Ll.ltrB was retargeted to invade three transposase genes, the tra gene found in IS904 (tra904), tra981, and tra983, of which 9, 10, and 14 copies, respectively, were present in IL1403-UCD. Intron invasion of tra904, tra981, and tra983 allele groups occurred at high frequencies, and individual segregants possessed anywhere from one to nine copies of intron in the respective tra alleles. To achieve multicopy delivery of a heterologous gene, a green fluorescent protein (GFP) marker was cloned into the tra904-targeted Ll.ltrB, and the resultant intron (Ll.ltrB::GFP) was induced to invade the L. lactis tra904 alleles. Segregants possessing Ll.ltrB::GFP in three, four, five, six, seven, and eight copies in different tra904 alleles were obtained. In general, increasing the chromosomal copy number of Ll.ltrB::GFP resulted in strains expressing successively higher levels of GFP. However, strains possessing the same number of Ll.ltrB::GFP copies within different sets of tra904 alleles exhibited differential GFP expression, and segregants possessing seven or eight copies of Ll.ltrB::GFP grew poorly upon induction, suggesting that GFP expression from certain combinations of alleles was detrimental. The highest level of GFP expression was observed from a specific six-copy variant that produced GFP at a level analogous to that obtained with a multicopy plasmid. In addition, the high level of GFP expression was stable for over 120 generations. This work demonstrates that stable multicopy integration of heterologous genes can be readily achieved in bacterial genomes with group II intron delivery by targeting repeated elements.


2008 ◽  
Vol 35 (3) ◽  
pp. 243-253 ◽  
Author(s):  
Sean T. Glenn ◽  
Craig A. Jones ◽  
Li Pan ◽  
Kenneth W. Gross

Renin is responsible for initiating the enzymatic cascade that results in the production of angiotensin II, the major effector molecule of the renin-angiotensin system (RAS). Extensive information on the regulatory region of the renin gene has been derived by transient transfection studies in vitro, particularly using the As4.1 cell line. To verify key factors within the regulatory region of renin in vivo, homologous recombination was used to introduce a green fluorescent protein (GFP) cassette into exon one of the renin gene contained within a 240 kb bacterial artificial chromosome (BAC) to create a construct that has GFP expression controlled by the renin regulatory region (RenGFP BAC). Within the regulatory region of the RenGFP BAC construct we independently deleted the enhancer, as well as mutated the HOX-PBX site within the proximal promoter element. Transgenic lines were generated for each of these BAC constructs and GFP expression was analyzed throughout a spectrum of tissues positive for renin expression including the kidney, adrenal gland, gonadal artery, and submandibular gland. The results described within this manuscript support the interpretation that the renin enhancer is critical for regulating baseline expression where as the Hox/Pbx site is important for the tissue specificity of renin expression.


2001 ◽  
Vol 360 (3) ◽  
pp. 645-649 ◽  
Author(s):  
Renu K. JAIN ◽  
Paul B. M. JOYCE ◽  
Miguel MOLINETE ◽  
Philippe A. HALBAN ◽  
Sven-Ulrik GORR

Green fluorescent protein (GFP) is used extensively as a reporter protein to monitor cellular processes, including intracellular protein trafficking and secretion. In general, this approach depends on GFP acting as a passive reporter protein. However, it was recently noted that GFP oligomerizes in the secretory pathway of endocrine cells. To characterize this oligomerization and its potential role in GFP transport, cytosolic and secretory forms of enhanced GFP (EGFP) were expressed in GH4C1 and AtT-20 endocrine cells. Biochemical analysis showed that cytosolic EGFP existed as a 27kDa monomer, whereas secretory forms of EGFP formed disulphide-linked oligomers. EGFP contains two cysteine residues (Cys49 and Cys71), which could play a role in this oligomerization. Site-directed mutagenesis of Cys49 and Cys71 showed that both cysteine residues were involved in disulphide interactions. Substitution of either cysteine residue resulted in a reduction or loss of oligomers, although dimers of the secretory form of EGFP remained. Mutation of these residues did not adversely affect the fluorescence of EGFP. EGFP oligomers were stored in secretory granules and secreted by the regulated secretory pathway in endocrine AtT-20 cells. Similarly, the dimeric mutant forms of EGFP were still secreted via the regulated secretory pathway, indicating that the higher-order oligomers were not necessary for sorting in AtT-20 cells. These results suggest that the oligomerization of EGFP must be considered when the protein is used as a reporter molecule in the secretory pathway.


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