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Uma Maheswari

Publications and source records attributed to Uma Maheswari.

7 recordsLinked to original sources
PubMed2005

Comparative genomics of the pennate diatom Phaeodactylum tricornutum.

Diatoms are one of the most important constituents of phytoplankton communities in aquatic environments, but in spite of this, only recently have large-scale diatom-sequencing projects been undertaken. With the genome of the centric species Thalassiosira pseudonana available since mid-2004, accumulating sequence information for a pennate model species appears a natural subsequent aim. We have generated over 12,000 expressed sequence tags (ESTs) from the pennate diatom Phaeodactylum tricornutum, and upon assembly into a nonredundant set, 5,108 sequences were obtained. Significant similarity (E < 1E-04) to entries in the GenBank nonredundant protein database, the COG profile database, and the Pfam protein domains database were detected, respectively, in 45.0%, 21.5%, and 37.1% of the nonredundant collection of sequences. This information was employed to functionally annotate the P. tricornutum nonredundant set and to create an internet-accessible queryable diatom EST database. The nonredundant collection was then compared to the putative complete proteomes of the green alga Chlamydomonas reinhardtii, the red alga Cyanidioschyzon merolae, and the centric diatom T. pseudonana. A number of intriguing differences were identified between the pennate and the centric diatoms concerning activities of relevance for general cell metabolism, e.g. genes involved in carbon-concentrating mechanisms, cytosolic acetyl-Coenzyme A production, and fructose-1,6-bisphosphate metabolism. Finally, codon usage and utilization of C and G relative to gene expression (as measured by EST redundance) were studied, and preferences for utilization of C and CpG doublets were noted among the P. tricornutum EST coding sequences.

Animals↗
PubMed2005

The Diatom EST Database.

The Diatom EST database provides integrated access to expressed sequence tag (EST) data from two eukaryotic microalgae of the class Bacillariophyceae, Phaeodactylum tricornutum and Thalassiosira pseudonana. The database currently contains sequences of close to 30,000 ESTs organized into PtDB, the P.tricornutum EST database, and TpDB, the T.pseudonana EST database. The EST sequences were clustered and assembled into a non-redundant set for each organism, and these non-redundant sequences were then subjected to automated annotation using similarity searches against protein and domain databases. EST sequences, clusters of contiguous sequences, their annotation and analysis with reference to the publicly available databases, and a codon usage table derived from a subset of sequences from PtDB and TpDB can all be accessed in the Diatom EST Database. The underlying RDBMS enables queries over the raw and annotated EST data and retrieval of information through a user-friendly web interface, with options to perform keyword and BLAST searches. The EST data can also be retrieved based on Pfam domains, Cluster of Orthologous Groups (COG) and Gene Ontologies (GO) assigned to them by similarity searches. The Database is available at http://avesthagen.sznbowler.com.

DNA, Algal↗
PubMed2005

Conscious cardiac surgery with cardiopulmonary bypass using thoracic epidural anesthesia without endotracheal general anesthesia.

OBJECTIVE: The purpose of this study was to evaluate the feasibility of thoracic epidural anesthesia as an alternative technique to general anesthesia in patients undergoing cardiac surgery under cardiopulmonary bypass. DESIGN: A prospective study. SETTING: Tertiary referral heart hospital. PARTICIPANTS: Eleven patients underwent cardiac surgical procedures requiring cardiopulmonary bypass under thoracic epidural anesthesia from February to April 2004. INTERVENTIONS: An epidural catheter was inserted at C7 to T2 intervertebral space on the day before the operation. Subsequently, cardiac surgery was performed using cardiopulmonary bypass. MEASUREMENTS AND RESULTS: The midsternotomy approach was used in all the patients. Anticoagulation was achieved with 300 units/kg of heparin. Under normothermic cardiopulmonary bypass, 6 patients underwent closure of atrial septal defect, 3 underwent valve replacements, and 2 underwent coronary artery bypass surgery combined with valve replacements. Soon after establishing cardiopulmonary bypass, all but 1 patient developed apnea, which was reversed after termination of cardiopulmonary bypass. The mean cardiopulmonary bypass time was 102 +/- 28 minutes, the aortic cross-clamp time was 58 +/- 28 minutes, and the total duration of surgery was 229 +/- 64 minutes. There was no mortality or morbidity in this series. CONCLUSION: Cardiac surgical procedures requiring cardiopulmonary bypass may be performed under thoracic epidural anesthesia, without endotracheal general anesthesia.

Adult↗
PubMed2005

Diatomics: toward diatom functional genomics.

For diatom biologists one of the most interesting research areas over the next years will be in linking mathematical models for pattern formation with information derived from molecular genetic, biochemical, and physiological studies. A major goal of this research is to exploit diatom proficiency in biogenic silica formation to develop strategies for bio-inspired nanofabrication of silicon based materials. Development of high-throughput methods for the functional analysis of diatom genes is a key step toward this goal. In this article we review the different techniques available to investigate gene and protein function in diatoms. Furthermore, to make diatom research as effective as possible the research community must address the question of which diatom species should be developed as a model. Choice of a diatom model organism should be made on the basis of several criteria, such as the ease of genetic manipulation, ecological relevance, or biomineralization capability. Phaeodactylum tricornutum is one of the principal three species that are candidates for such a model. For this species we have accomplished the first large-scale analysis of 12000 expressed sequence tags (ESTs) and have organized it in a queryable database, Phaeodactylum tricornutum database (PtDB). A summary of the functional analysis of this EST collection is presented, and genes of particular interest are highlighted.

Chromosome Mapping↗
PubMed2005

Cardiopulmonary bypass in conscious patients undergoing cardiac surgery.

This study was undertaken to evaluate the feasibility of thoracic epidural anesthesia as an alternative technique to general anesthesia in patients undergoing cardiac surgery under cardiopulmonary bypass. This prospective study was conducted in a tertiary referral hospital. Seventeen patients underwent cardiac surgical procedures requiring cardiopulmonary bypass without general anesthesia under thoracic epidural anesthesia from February to May 2004. An epidural catheter was inserted at any of intervertebral spaces from C7 to T2 on the day before surgery. Subsequently, cardiac surgery was performed under normothermic cardiopulmonary bypass, during which the patients remained conscious. The types of surgery included closure of atrial septal defects, valve replacements, and combined bypass surgery and valve replacements. Approach to the heart was obtained through midsternotomy. Anticoagulation was achieved with 300 units/kg of heparin. Normothermic cardiopulmonary bypass was initiated slowly during the course of 10 to 15 min. Nonpulsatile flow was administered using centrifugal pump and mean perfusion pressure was maintained in the range of 70-80 mmHg. The planned surgical procedure could be performed in all the patients. Soon after establishing cardiopulmonary bypass, the patients developed apnea, which reverted to normalcy a few minutes after disconnection of cardiopulmonary bypass. The mean time for cardiopulmonary bypass was 102 +/- 28 min, aortic cross clamp time was 58 +/- 28 min, and the total duration of surgery was 229 +/- 64 min. None of the patients required conversion to general anesthesia. There was no mortality or morbidity in this series and to our knowledge our series is the first such. Cardiac surgical procedures requiring cardiopulmonary bypass may be conducted under thoracic epidural anesthesia, without endotracheal general anesthesia.

Adult↗