58 research outputs found
IDDQ testing of a CMOS first order sigma-delta modulator of an 8-bit oversampling ADC
This work presents IDDQ testing of a CMOS first order sigma-delta modulator of an 8-bit oversampling analog-to-digital converter using a built-in current sensor [BICS]. Gate-drain, source-drain, gate-source and gate-substrate bridging faults are injected using fault injection transistors. All the four faults cause varying fault currents and are successfully detected by the BICS at a good operation speed. The BICS have a negligible impact on the performance of the modulator and an external pin is provided to completely cut-off the BICS from the modulator. The modulator was designed and fabricated in 1.5 μm n-well CMOS process. The decimator was designed on Altera\u27s FLEXE20K board using Verilog. The modulator and decimator were assembled together to form a sigma-delta ADC
Evolved to Break Free: Evolution and Diversity in Single Gene Lysis
mall lytic phages compelled by the same evolutionary pressures as large dsDNA phages have evolved mechanisms to lyse their hosts efficiently and at optimal times to ensure maximum fecundity. The ssDNA Microviridae and ssRNA Leviviridae, with extremely small genomes (<6kb), effect lysis with a single gene. The most studied single-gene lysis systems (SGL) are gene E of the canonical microvirus PhiX174 and genes A2 and L of the paradigm ssRNA phages Qβ and MS2, respectively. All three lysis proteins lack muralytic activity, and two, A2 and E, have been shown to function as “protein antibiotics” by acting as noncompetitive inhibitors of conserved peptidoglycan (PG) biosynthesis enzymes, MurA and MraY, respectively. The third, L of MS2, does not inhibit PG biosynthesis but instead is hypothesized to trigger host autolytic response through an unknown mechanism.
The work described in this dissertation identifies a chaperone involved in MS2 L-mediated lysis, the minimal lytic domain of L, and a new paradigm in SGL that resolves a long-standing debate in peptidoglycan biosynthesis. Using a genetic approach, dnaJ was shown to be required for L-mediated lysis. DnaJ was shown to form a complex with L and this interaction is abrogated in the absence of the highly basic N-terminal half of L. Mutational analysis of L has revealed that most critical residues are clustered around a highly-conserved LS motif. To determine if SGL evolved at different genomic locations target other steps in PG biosynthesis we studied of the lysis mechanism of Lys^M from an E. coli phage M. Both genetic and biochemical analysis have demonstrated that Lys^M targets MurJ, the proposed Lipid II flippase candidate, and blocks Lipid II flipping to effect host lysis. Thus, the results presented in this dissertation provide the most convincing evidence in favor of MurJ being the Lipid II flippase. Additionally, the results highlight the plasticity of ssRNA phages to evolve inhibitors against proteins involved in PG biosynthesis and maintenance
Effects of salinity, alkalinity, and acidity on crop growth and development on pea (Pisum sativum)
Effects of salinity, alkalinity, and acidity on crop growth and development
on pea (Pisum sativum)
Authors: Laxmi Prasanna Shakamudi, Rasagna Chamakura, Vineela Bathula
Mentor: Dr. Megan Taylor
Hutson school of agriculture, Murray state university
Pea (Pisum sativum) is one of the vegetables that belong to the Fabaceae family, is a pulse crop that has been widely used and cultivated in all parts of the world. As with many crops pea plants also experience abiotic stresses that affect the plant’s growth, development, and productivity. Abiotic stresses that affect crop growth and development include soil salinity, alkalinity, and acidity. This study was conducted to determine the effect of salinity, alkalinity, and acidity on the growth and development of pea plants that were grown in plastic cups in which soil is treated with different levels of salinity, alkalinity, and acidity. Each treatment is replicated 3 depending on the levels of treatment. Root morphology and length were determined on day 13 at the time of harvest. Results indicate that pea germination was negatively affected by the soil under salt stress and alkaline stress condition and maximum seed germination were observed with the control with 100% germination rate. The acid-treated soil was measured with a 66% germination rate. The study determines that salinity and alkalinity have negative effects on the germination, growth, and development of pea plants. Acidic soils at lower concentrations did not affect germination and growth, as a concentration of acidic levels increased there was a negative impact on germination and growth for pea plants. For shoot length, root length, and emergence, the T-test revealed substantial variations between control and acidity. Comparable results are seen for chlorophyll fluorescence.
Keywords: Pea (Pisum sativum), Salt stressed soils, Alkaline soils, and Acidic soils
MS2 Lysis of Escherichia coli Depends on Host Chaperone DnaJ
ABSTRACT
The L protein of the single-stranded RNA phage MS2 causes lysis of
Escherichia coli
without inducing bacteriolytic activity or inhibiting net peptidoglycan (PG) synthesis. To find host genes required for L-mediated lysis, spontaneous Ill (
i
nsensitivity to
L
l
ysis) mutants were selected as survivors of L expression and shown to have a missense change of the highly conserved proline (P330Q) in the C-terminal domain of DnaJ. In the
dnaJ
P330Q
mutant host, L-mediated lysis is completely blocked at 30°C without affecting the intracellular levels of L. At higher temperatures (37°C and 42°C), both lysis and L accumulation are delayed. The lysis block at 30°C in the
dnaJ
P330Q
mutant was recessive and could be suppressed by
L
o
vercomes
d
na
J
(
L
odj
) alleles selected for restoration of lysis. All three
L
odj
alleles lack the highly basic N-terminal half of the lysis protein and cause lysis ∼20 min earlier than full-length L. DnaJ was found to form a complex with full-length L. This complex was abrogated by the P330Q mutation and was absent with the L
odj
truncations. These results suggest that, in the absence of interaction with DnaJ, the N-terminal domain of L interferes with its ability to bind to its unknown target. The lysis retardation and DnaJ chaperone dependency conferred by the nonessential, highly basic N-terminal domain of L resembles the SlyD chaperone dependency conferred by the highly basic C-terminal domain of the E lysis protein of ϕX174, suggesting a common theme where single-gene lysis can be modulated by host factors influenced by physiological conditions.
IMPORTANCE
Small single-stranded nucleic acid lytic phages (
Microviridae
and
Leviviridae
) lyse their host by expressing a single “protein antibiotic.” The protein antibiotics from two out of three prototypic small lytic viruses have been shown to inhibit two different steps in the conserved PG biosynthesis pathway. However, the molecular basis of lysis caused by L, the lysis protein of the third prototypic virus, MS2, is unknown. The significance of our research lies in the identification of DnaJ as a chaperone in the MS2 L lysis pathway and the identification of the minimal lytic domain of MS2 L. Additionally, our research highlights the importance of the highly conserved P330 residue in the C-terminal domain of DnaJ for specific protein interactions.
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Disinfection and removal performance for Escherichia coli and heavy metals by silver-modified zeolite in a fixed bed column
Antibacterial effect of silver (I) carbohydrate complexes on oral pathogenic key species in vitro
FS using CPCM
MATLAB code for feature selection using Conditional Priority Coverage Maximization (CPCM). The text file readme.txt has further details on the usage of the code
Detecting Object Position Using Sensor Data
This report deals with detecting object position using sensor datausing three different types of sensors held at four corners of a givendimensional plate; two sensors of URM09 Analog, 1 of URM09 Ultrasonic and 1 of VL6180X ToF sensor. The accuracy of the sensors performance is investigated using relative standard deviation. The results show that the proposed solution allows to estimate the objectposition and size without significant error
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