Joseph M. Merrick

The Minimal Gene Complement of Mycoplasma genitalium

The complete nucleotide sequence (580,070 base pairs) of the Mycoplasma genitalium genome, the smallest known genome of any free-living organism, has been determined by whole-genome random sequencing and assembly. A total of only 470 predicted coding regions were identified that include genes required for DNA replication, transcription and translation, DNA repair, cellular transport, and energy metabolism. Comparison of this genome to that of Haemophilus influenzae suggests that differences in genome content are reflected as profound differences in physiology and metabolic capacity between these two organisms.

The Schistosoma mansoni gene index: Gene discovery and biology by reconstruction and analysis of expressed gene sequences

Expressed sequence tag (EST) sequencing and analysis is a primary research tool to identify and characterize the Schistosoma mansoni transcriptome. As part of our gene discovery effort, a total of 5,793 ESTs have been generated from clones selected randomly from complementary DNA (cDNA) libraries constructed from male and female adult worms. Assembly analysis of all the 16,813 public S. mansoni ESTs has identified 1,920 distinct tentative consensus sequences (TCs) and 5,571 nonoverlapping ESTs (singletons). Of these, 376 TCs (20%) and 1,449 singletons (26%) are unique to the SUNY/TIGR sequencing effort. Tentative consensus sequences and singletons were distributed into various categories of biological roles associated with cell structure, metabolism, protein fate, signal transduction, transcription, protein synthesis, transporters, and cell growth. The TCs and singletons represent transcripts that can be used as a resource for functional annotation of genomic sequence data, comparative sequence analysis, and cDNA clone selection for microarray projects. The utility of EST analysis is demonstrated by identifying new protease genes, which may be involved in hemoglobin degradation.

Classification of Human Heterophile Antibodies

A classification of heterophile antibodies is proposed, which is based on interactions with guinea pig kidney homogenate. The major groups of antibodies combining with guinea pig kidney encompass Hanganutziu-Deicher antibodies, Forssman antibodies, and antibodies to Newcastle disease virus. Antibodies which fail to combine with guinea pig kidney are primarily those of Paul-Bunnell variety.

Formation of heterophile antibodies by human tonsilar lymphocytes: I. In vitro stimulation with heterologous antigens

Abstract Short term cultures of human tonsilar lymphocytes (HTL) in a medium with human AB serum were studied for production of plaque forming cells (PFC) against bovine (BRBC) and sheep red blood cells (SRBC) following in vitro stimulation by various antigens. Stimulation by BRBC or SRBC resulted in production of significant number of PFC against BRBC and SRBC, 100 to 500/10 6 HTL, 4 to 8 days after initiation of the cultures. Seven of 10 HTL specimens stimulated by BRBC produced PFC against both BRBC and SRBC and three gave negative results. Of 12 SRBC-stimulated HTL samples, five produced PFC against both SRBC and BRBC, four against SRBC only and the remaining three gave negative results. Evidence was presented that E rosetting cells (T) as well as plastic-adhering cells were required for the in vitro PFC responses. Stimulation of HTL by murine thymocytes or by murine lymphoma EL-4 cells resulted also in formation of PFC against both BRBC and SRBC. Antibodies secreted by the PFC were studied by inhibition tests with solubilized heterophile antigens. These studies demonstrated that Hanganutziu-Deicher antibodies were secreted by PFC produced by HTL stimulated by BRBC as well as by SRBC and that Forssman antibodies were secreted by PFC formed by SRBC-stimulated HTL. Demonstration of P-B antibodies was not unequivocal. Stimulation by Hanganutziu-Deicher antigen induced in seven of 19 HTL specimens formation of PFC against BRBC and SRBC and stimulation by Paul-Bunnell antigen resulted in formation of PFC against BRBC or against BRBC and SRBC in four of 25 specimens.

Studies on Paul-Bunnell (P-B) Antigen-Antibody System

Preparations obtained by the chloroform-methanol extraction procedure from spleen tissues of patients with Hodgkins disease, lymphomas, and leukemias, as well as from peripheral blood buffy coat of infectious mononucleosis (IM) patients were studied for the presence of 2 Paul-Bunnell (P-B) antigens; BS antigen shared by bovine red blood cells (BRBC) and sheep red blood cells (SRBC) and another, B antigen characteristic for BRBC. Both BS and B antigens were demonstrated by means of agglutination inhibition tests in over 40% of these extracts. None of the extracts from spleens, tonsils, and buffy coat of apparently normal human beings contained these antigens. P-B antigens of lymphoma-leukemia extracts were further purified by DEAE-Sephadex column chromatography. The purified fractions of some of these spleen extracts formed a precipitation line with IM sera, which merged into a reaction of identity with the lines formed by P-B antigens of BRBC. In studying various pathologic sera, B antigen was detected in sera of 28% of lymphoma-leukemia patients, 15% of patients with carcinomas of internal organs, and 3% of patients with systemic lupus erythematosus. On the other hand, BS antigen was found in only 3% of lymphoma-leukemia sera. These results confirmed our previous observations and indicated that both BS and B antigens are expressed as neoantigens on the patients spleen cells as a result of pathologic processes in lymphoreticular malignancies.

A glycopeptide resistant to exoglycosidases

Abstract The carboxyl group of the terminal N-acetylneuraminic acid residue of the glycopeptide, prepared from α1-acid glycoprotein by protease digestion, was esterified with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and then reduced with sodium borohydride. The reduced glycopeptide, thus prepared, containing the reduced N-acetylneuraminic acid, was resistant to hydrolysis by neuraminidase, and consequently to other exoglycosidases. The penultimate β- d -galactosyl residue of the oligosaccharide chain of the reduced glycopeptide was hydrolyzed by β- d -galactosidase only after the removal of the terminal, reduced, sialic acid by mild hydrolysis with acid. The reduced glycopeptide should be a useful substrate for the assay of endoglycosidases in the presence of exoenzymes. It should also find use as a carbon source in the growth of endoglycosidase-elaborating bacteria.