Biomedical subjects

S Pappu

Publications and source records attributed to S Pappu.

4 recordsLinked to original sources

PubMed1998

Sequence characteristics of natural populations of tomato spotted wilt tospovirus infecting flue-cured tobacco in Georgia.

Using primers from conserved regions, the nucleocapsid (Nc) gene sequences of naturally occurring tomato spotted wilt tospovirus (TSWV) isolates from flue-cured tobacco (Nicotiana tabacum) grown in several Georgia counties were amplified by immunocapture-reverse transcription-polymerase chain reaction. The resulting amplicons were cloned and sequenced. Sequence analyses showed a high degree of sequence conservation among the Nc genes of the tobacco isolates, and those reported from other parts of the world. However, distinct differences that were unique to these tobacco isolates as well as the previously studied peanut, tomato and pepper isolates from Georgia were present. The Georgia isolates formed a distinct cluster that was clearly resolved from the rest of the TSWV isolates based on sequence phylograms.

Base Sequence↗

PubMed1997

A robust point-matching algorithm for autoradiograph alignment.

We present a novel method for the geometric alignment of autoradiographs of the brain. The method is based on finding the spatial mapping and the one-to-one correspondences (or homologies) between point features extracted from the images and rejecting non-homologies as outliers. In this way, we attempt to account for the local, natural and artifactual differences between the autoradiograph slices. We have used the resulting automated algorithm on a set of left prefrontal cortex autoradiograph slices, specifically demonstrated its ability to perform point outlier rejection, validated its robustness property using synthetically generated spatial mappings and provided an anecdotal visual comparison with the well-known iterated closest-point (ICP) algorithm. Visualization of a stack of aligned left prefrontal cortex autoradiograph slices is also provided.

Algorithms↗

PubMed1993

Comparative sequence analysis of the coat proteins of biologically distinct citrus tristeza closterovirus isolates.

The genome of citrus tristeza closterovirus (CTV) consists of a 20 kb single-stranded RNA encapsidated in a 2000 nm long, flexuous particle. Double-stranded (replicative form) RNAs purified from CTV-infected tissue were used to prepare complementary DNA libraries that involved initial first-strand cDNA synthesis followed by selective amplification of the coat protein gene. CTV-specific antisera were used to select clones expressing the coat protein. The coat protein genes of seven Florida and four exotic isolates that differ in their biological properties were cloned and sequenced. The gene is 669 base pairs long and encodes a 223 amino acid protein. There was a greater than 80% homology at both nucleotide and amino acid levels among all the isolates examined. However, comparisons showed that each isolate was found to have several unique amino acid residues. Several blocks of amino acid residues were conserved among all the isolates. A cluster dendrogram showed greater similarities among groups of mild and severe Florida isolates that differed significantly from those of the geographically distinct, exotic CTV isolates.

Amino Acid Sequence↗

PubMed1986

Fascia patch graft for a digital flexor sheath defect over primary tendon repair in the chicken.

The histologic appearance of 14 chicken flexor tendon repair sites with a defect in the tendon sheath was compared with 14 covered by fascia patch grafts. Half the animals (seven with and seven without the patch) were studied 3 weeks after surgery and the other half 8 weeks after surgery. The qualitative microscopic examination showed that the area of healing was better organized with less restrictive-appearing adhesions when the sheath defect was grafted.

Animals↗