6,128 research outputs found
Development of the CRISPR/Cas9 System for Targeted Gene Disruption in Aspergillus Fumigatus
Low rates of homologous recombination have broadly encumbered genetic studies in the fungal pathogen Aspergillus fumigatus. The CRISPR/Cas9 system of bacteria has recently been developed for targeted mutagenesis of eukaryotic genomes with high effi- ciency and, importantly, through a mechanism independent of homologous repair machinery. As this new technology has not been developed for use in A. fumigatus, we sought to test its feasibility for targeted gene disruption in this organism. As a proof of principle, we first demonstrated that CRISPR/Cas9 can indeed be used for high-efficiency (25 to 53%) targeting of the A. fu- migatus polyketide synthase gene (pksP), as evidenced by the generation of colorless (albino) mutants harboring the expected genomic alteration. We further demonstrated that the constitutive expression of the Cas9 nuclease by itself is not deleterious to A. fumigatus growth or virulence, thus making the CRISPR system compatible with studies involved in pathogenesis. Taken to- gether, these data demonstrate that CRISPR can be utilized for loss-of-function studies in A. fumigatus and has the potential to bolster the genetic toolbox for this important pathogen
Differentiation of primate primordial germ cell-like cells following transplantation into the adult gonadal niche.
A major challenge in stem cell differentiation is the availability of bioassays to prove cell types generated in vitro are equivalent to cells in vivo. In the mouse, differentiation of primordial germ cell-like cells (PGCLCs) from pluripotent cells was validated by transplantation, leading to the generation of spermatogenesis and to the birth of offspring. Here we report the use of xenotransplantation (monkey to mouse) and homologous transplantation (monkey to monkey) to validate our in vitro protocol for differentiating male rhesus (r) macaque PGCLCs (rPGCLCs) from induced pluripotent stem cells (riPSCs). Specifically, transplantation of aggregates containing rPGCLCs into mouse and nonhuman primate testicles overcomes a major bottleneck in rPGCLC differentiation. These findings suggest that immature rPGCLCs once transplanted into an adult gonadal niche commit to differentiate towards late rPGCs that initiate epigenetic reprogramming but do not complete the conversion into ENO2-positive spermatogonia
Metrology Camera System of Prime Focus Spectrograph for Subaru Telescope
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber
spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS
will cover a 1.3 degree diameter field with 2394 fibers to complement the
imaging capabilities of Hyper SuprimeCam. To retain high throughput, the final
positioning accuracy between the fibers and observing targets of PFS is
required to be less than 10um. The metrology camera system (MCS) serves as the
optical encoder of the fiber motors for the configuring of fibers. MCS provides
the fiber positions within a 5um error over the 45 cm focal plane. The
information from MCS will be fed into the fiber positioner control system for
the closed loop control. MCS will be located at the Cassegrain focus of Subaru
telescope in order to to cover the whole focal plane with one 50M pixel Canon
CMOS camera. It is a 380mm Schmidt type telescope which generates a uniform
spot size with a 10 micron FWHM across the field for reasonable sampling of
PSF. Carbon fiber tubes are used to provide a stable structure over the
operating conditions without focus adjustments. The CMOS sensor can be read in
0.8s to reduce the overhead for the fiber configuration. The positions of all
fibers can be obtained within 0.5s after the readout of the frame. This enables
the overall fiber configuration to be less than 2 minutes. MCS will be
installed inside a standard Subaru Cassgrain Box. All components that generate
heat are located inside a glycol cooled cabinet to reduce the possible image
motion due to heat. The optics and camera for MCS have been delivered and
tested. The mechanical parts and supporting structure are ready as of spring
2016. The integration of MCS will start in the summer of 2016.Comment: 11 pages, 15 figures. SPIE proceeding. arXiv admin note: text overlap
with arXiv:1408.287
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Referral Center Experience With Nonpalpable Contraceptive Implant Removals.
ObjectiveTo describe our experience with office removal of nonpalpable contraceptive implants at our referral center.MethodsWe performed a retrospective cohort study by reviewing the charts of patients referred to our family planning specialty center for nonpalpable or complex contraceptive implant removal from January 2015 through December 2018. We localized nonpalpable implants using high-frequency ultrasonography and skin mapping in radiology, followed by attempted removal in the office using local anesthesia and a modified vasectomy clamp. We abstracted information on demographics, implant location, and outcomes.ResultsOf 61 referrals, 55 patients attended their scheduled appointments. Seven patients had palpable implants; six elected removal. The other 48 patients had ultrasound localization, which identified 47 (98%) of the implants; the remaining patient had successful localization with computed tomography imaging. Nonpalpable implants were suprafascial (n=22), subfascial (n=25) and intrafascial (n=1); four of these patients opted to delay removal. Of 50 attempted office removals, all palpable (n=6), all nonpalpable suprafascial (n=21 [100%, 95% CI 83-100%]), and 19 out of 23 (83%, 95% CI 67-98%) subfascial implants were successful. Three of the four patients with failed subfascial implant office removal had successful operating room removal with a collaborative orthopedic surgeon; the other patient sought removal elsewhere. Transient postprocedure neuropathic complaints were noted in 7 out of 23 (30%, 95% CI 12-49%) subfascial and 1 out of 21 (5%, 95% CI 0-13%) suprafascial removals (P=.048). Nonpalpable implants were more likely to be subfascial in nonobese patients (24/34, 71%) as compared with obese (1/13, 8%) patients (P<.001). Seven (28%) of the 25 subfascially located implants had been inserted during a removal-reinsertion procedure through the same incision.ConclusionMost nonpalpable contraceptive implants can be removed in the office by an experienced subspecialty health care provider after ultrasound localization. Some patients may experience transient postprocedure neuropathic pain. Nonpalpable implants in thinner women are more likely to be in a subfascial location
Integrating Design Throughout The Mechanical Engineering Curriculum: A Focus On The Engineering Clinics
At Rowan University, we have infused design into the curriculum through an eight-semester course sequence called the Engineering Clinic. Through this experience students learn the art and science of design in a multidisciplinary team environment. While many engineering programs currently include a Capstone Design course taken near the end of the college career to meet the design needs, Engineering Clinic at Rowan allows students to hone their design skills throughout their four-year career. This paper will describe in further detail the objectives and execution of each year in the design sequence, types of projects and how the Clinics complement traditional core courses in the curriculum. Impacts and benefits of the Clinics on students and faculty are discussed, as well as comparative data of Rowan Mechanical Engineering students and their peers nationally
Restriction endonuclease TseI cleaves A:A and T:T mismatches in CAG and CTG repeats.
The type II restriction endonuclease TseI recognizes the DNA target sequence 5'-G^CWGC-3' (where W = A or T) and cleaves after the first G to produce fragments with three-base 5'-overhangs. We have determined that it is a dimeric protein capable of cleaving not only its target sequence but also one containing A:A or T:T mismatches at the central base pair in the target sequence. The cleavage of targets containing these mismatches is as efficient as cleavage of the correct target sequence containing a central A:T base pair. The cleavage mechanism does not apparently use a base flipping mechanism as found for some other type II restriction endonuclease recognizing similarly degenerate target sequences. The ability of TseI to cleave targets with mismatches means that it can cleave the unusual DNA hairpin structures containing A:A or T:T mismatches formed by the repetitive DNA sequences associated with Huntington's disease (CAG repeats) and myotonic dystrophy type 1 (CTG repeats)
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