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N Sarker

Publications and source records attributed to N Sarker.

5 recordsLinked to original sources
PubMed2004

Radiation hybrid map assignments of 11 ESTs obtained from a 28-day-old swine embryo cDNA library to the IMpRH map.

In order to improve the map resolution and to locate more genes on the porcine radiation hybrid map, expressed sequence tags (ESTs) were isolated from a 28-day-old normal pig embryo cDNA library. The ESTs were sequenced from the 5'-end and similarities were checked with sequences registered in the NCBI DNA database (http://www.ncbi.nlm.nih.gov/blast/). The ESTs sequences which have high identity scores (>80%) against human genes or ESTs were further sequenced from the 3' untranslated region. The ESTs which were sequenced successfully were used to design primers for PCR analysis of the radiation hybrid panel. Eleven ESTs were physically mapped to porcine chromosomes 2, 4, 8, 10, 13, 14 and X. The localizations are in agreement with the comparative mapping data between human and pig. The results will provide unique information to the comparative map of human and pig.

Animals↗
PubMed2001

Directed isolation and mapping of microsatellites from swine Chromosome 1q telomeric region through microdissection and RH mapping.

Several quantitative trait loci (QTLs) (vertebrate number, birth weight, age at puberty, growth rate, gestation length, and backfat depth) have been independently mapped to the distal region of swine Chromosome (SSC) 1q in several resource populations. In order to improve the map resolution and refine these QTLs more precisely on SSC1q, we have isolated and mapped additional microsatellites (ms), using chromosome microdissection and radiation hybrid (RH) mapping. Five copies of the telomeric region of SSC1q were microdissected from metaphase spreads and pooled. The chromosomal fragment DNA was randomly amplified by using degenerate oligonucleotide primed polymerase chain reaction (DOP-PCR), enriched for ms, and subcloned into a PCR vector. Screening of subsequent clones with ms probes identified 23 unique ms sequences. Fifteen of these (65%) were subjected to radiation hybrid (RH) mapping by using the INRA-University of Minnesota porcine RH panel (IMpRH); and the remaining eight were not suited for the RH mapping. Twelve microsatellites were assigned to SSC1q telomeric region of IMpRH map (LOD >6), and three remain unlinked (LOD <6). Out of the 15 microsatellite markers, 9 were polymorphic in NIAI reference population based on the Meishan and Göttingen miniature pig. In summary, we have used microdissection and radiation hybrid mapping to clone and map 12 new microsatellites to the swine gene map to increase the resolution of SSC1q in the region of known QTLs.

Animals↗
PubMed2000

Cell-mediated and humoral immunity and phagocytic ability in chicken Lines divergently selected for serum immunoglobulin M and G levels.

Humoral and cell-mediated immunities and phagocytic ability were examined at the third and fourth generations of selection in two pairs of chicken lines (at 10 wk of age) that were divergently selected for levels of high serum Ig M (HIM), low serum Ig M (LIM), high serum Ig G (HIG), and low serum Ig G (LIG). Cell-mediated immunity was examined by splenomegaly assay at 12 wk of age. At 20 and 23 wk of age, 20 birds from the respective lines were injected Brucella abortus (BA), and blood samples were collected at 7 and 14 d postprimary immunization (PPI) and postsecondary immunization (PSI). Phagocytic ability was measured by carbon clearance assay at 25 and 30 wk of age. The results showed that the LIG line had higher degree of splenomegaly indices than the HIG line in both generations. The HIM and HIG lines had significantly (P < 0.05) higher total antibody titers to BA than their low counterparts. Similarly, mercaptoethanol-resistant (MER) antibody titers to BA, as measured only in the fourth generation, were significantly (P < 0.05) higher in the HIM and HIG lines than their low counterparts. In both generations, the HIM and HIG lines had significantly (P < 0.01) faster carbon clearance ability than the LIM and LIG lines. The results suggest that both pairs of selected lines exhibited divergence in immunocompetence, although they had been selected for serum Ig isotypes.

Animals↗
PubMed1999

Direct and correlated response to divergent selection for serum immunoglobulin M and G levels in chickens.

Two pairs of chicken lines were divergently selected for serum immunoglobulin M and G levels at 10 wk of age to examine the effect of selection on direct and correlated traits. After three generations of selection, the lines were tested for their ability of antibody production against SRBC, a T cell dependent antigen. At 14 and 17 wk of age, the lines were immunized intravenously with 1 mL of 5% SRBC solution. Blood samples were collected at 7 and 14 d of post primary immunization (PPI) and post secondary immunization (PSI). Selection was effective (P < 0.01) in changing the serum immunoglobulin M levels. The G levels were changed in a downward direction initially in the high line. The differences between the high immunoglobulin M (HIM) and low immunoglobulin M (LIM) lines as well as high immunoglobulin G (HIG) and low immunoglobulin G (LIG) lines became larger during the course of selection. Selection differentials varied considerably during the selection, but the selection response was almost constant. Realized heritability was relatively high, ranging from 0.58 to 0.66 and from 0.40 to 0.60 for the IgM and IgG selected lines, respectively. Total antibody titers to SRBC differed significantly (P < 0.01) between the HIM and LIM lines at 7 and 14 d PPI, and 7 d PSI. The HIM line also produced significantly higher mercaptoethanol resistant antibody titers to SRBC than the LIM line at 7 and 14 d PPI and PSI. The LIG line had significantly higher total antibody titers to SRBC than the HIG line at both 7 and 14 d of PPI and PSI. From these results, it is suggested that selection of chickens on the basis of serum immunoglobulin isotypes may change antibody producing cells as well as other immunocompetent cells that modulate the immune response of the selected lines.

Animals↗