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S Ferris

Publications and source records attributed to S Ferris.

At least 37 records · Page 2Linked to original sources
PubMed1995

Characterization of a major Mycoplasma penetrans lipoprotein and of its gene.

A novel mycoplasmal species designated as Mycoplasma penetrans has been isolated recently from patients infected with human immunodeficiency virus. p35, a major antigen extracted from the membrane of this mycoplasma using Triton X-114 has been found to be a lipoprotein. After proteolytic treatment of p35, the sequence of one of the resulting peptides was determined and a corresponding oligonucleotide was deduced. Using this oligonucleotide as a probe the p35 gene was cloned and sequenced. Sequence analysis revealed an amino-terminal signal peptide with a potential acylation site which would result in a 35.3 kDa mature product. In addition, the p35 gene was followed by an open reading frame with a corresponding polypeptide partially homologous to p35, in particular to the N-terminus region.

Amino Acid Sequence↗
PubMed1994

Different proliferative response of human and chimpanzee lymphocytes after contact with human immunodeficiency virus type 1 gp120.

T cell functional defects are a common aspect of human immunodeficiency virus (HIV) infection. Moreover, it has been suggested that indirect mechanisms are involved in CD4+ cell depletion. Unresponsiveness to proliferative stimuli of lymphocytes incubated with HIV particles or with viral proteins is well documented. Nevertheless, drawing a clear picture of the anergy phenomenon is difficult because of several unresolved and controversial questions. Here we report that recombinant gp120 induces anergy in T helper lymphocytes cultured with different stimuli. The proliferative responses to interleukin (IL)-2, IL-4, IL-6, anti-CD2, anti-CD3 and phorbol 12-myristate 13-acetate are inhibited. Moreover, anergic cells show a different distribution in cell cycle phases as compared to control cells, leading us to suggest that the progression in the cell cycle is hampered and that a pre-mitotic block takes place. Furthermore, since chimpanzees are susceptible to HIV-1 infection without showing immunodeficiency signs, we analyzed the proliferation of chimpanzee lymphocytes without observing anergy in cells preincubated with gp120. Taken together, these results support the hypothesis that anergy plays an important role in HIV infection in vivo.

Animals↗
PubMed1994

Molecular characterization of the P1-like adhesin gene from Mycoplasma pirum.

A DNA fragment has been isolated from the genome of Mycoplasma pirum by use of a genetic probe derived from the conserved region within the genes for the major adhesins of Mycoplasma genitalium and Mycoplasma pneumoniae. A gene encoding an adhesin-like polypeptide was localized, and sequence analysis indicated a G + C content of only 28%, with A- and T-rich codons being preferentially used. A total of 91% of positions 3 were either A or T. The deduced polypeptide is 1,144 amino acids long (126 kDa) and shows 26% identity with the adhesins of M. genitalium and M. pneumoniae. Other features in common with these two membrane proteins include a similar hydropathic profile and a proline-rich C terminus. Antibodies were prepared by using as an immunogen a peptide derived from the C terminus of the M. pirum adhesin-like polypeptide and were found to recognize on immunoblots a 126-kDa polypeptide from an M. pirum cellular extract. The characterization of the adhesin-like gene is a first step toward a better understanding of the mechanisms allowing this human mycoplasma to attach to host cells.

Adhesins, Bacterial↗
PubMed1993

Identification of Mycoplasma pirum genes involved in the salvage pathways for nucleosides.

Genes encoding enzymes involved in the salvage pathway for nucleosides have been cloned and sequenced from the mollicute Mycoplasma pirum. One of them, encoding deoxyriboaldolase, was functionally identified by complementation of an Escherichia coli mutant. These genes are clustered, suggesting an operon organization, and they are immediately followed by the putative gene for the triose phosphate isomerase, an enzyme used during glycolysis.

Aldehyde-Lyases↗
PubMed1990

Isolation of recombinant fragments of the major outer-membrane protein of Chlamydia trachomatis: their potential as subunit vaccines.

Recombinant fragments of the major outer-membrane protein (MOMP) of Chlamydia trachomatis, expressed at high levels in Escherichia coli, were isolated and purified. Antisera to the recombinant proteins reacted preferentially with overlapping synthetic peptides covering the immunoaccessible variable segments of MOMP. These sera also reacted in a species-specific manner with the surface of intact infectious elementary bodies, and in a Chlamydia genus-specific manner in assays using denatured or bound chlamydial antigens. The ability of recombinant MOMP preparations to elicit antibody to the surface of chlamydial elementary bodies raises the possibility that these proteins may be useful for chlamydial vaccine development.

Animals↗
PubMed1990

The major outer-membrane proteins of Chlamydia trachomatis serovars A and B: intra-serovar amino acid changes do not alter specificities of serovar- and C subspecies-reactive antibody-binding domains.

The major outer-membrane protein (MOMP) of Chlamydia trachomatis is a promising candidate antigen for chlamydial vaccine development. We have sequenced the MOMP genes for a serovar A and a serovar B isolate and have compared these new sequences with those already reported. Intra-serovar changes in the inferred amino acid sequences of the surface-exposed variable segments known to be responsible for binding of neutralizing antibody were observed. Nevertheless, epitope mapping with solid-phase peptides showed that these intra-serovar changes did not affect the binding of serovar- and subspecies-specific, potentially protective antibodies. Variable segment 1 of C. trachomatis serovar A contained two adjacent antibody-binding sites, one of which was C-subspecies specific while the other was serovar A specific. Therefore the subspecies binding site for C-complex organisms is in variable segment 1, whilst that for B-complex organisms is in variable segment 4. This work shows that MOMP sequences are relatively stable within the serovar categorization for isolates taken decades apart from different continents. Within a given serovar, however, limited interchange of functionally related amino acids may occur without impairing the binding of serovar-specific antibody.

Amino Acid Sequence↗
PubMed1989

Surface-exposed epitopes on the major outer-membrane protein of Chlamydia trachomatis defined with peptide antisera.

The surface exposure of computer-predicted, linear B-cell epitopes on the major outer-membrane protein (MOMP) of Chlamydia trachomatis serovar B was assessed using antibodies raised against synthetic peptides in conjunction with immunogold transmission electron microscopy. Several of the chosen peptides elicited antibodies which reacted with both denatured and native MOMP. The majority of the exposed epitopes were found within the variable segments of MOMP. For each of the epitopes identified, the extent of their surface accessibility varied both among individual organisms and different developmental forms. Evidence for two distinct subspecies-specific epitopes within VS4 is presented.

Amino Acid Sequence↗
PubMed1983

First results on the effects of MAO inhibition on cognitive functioning in elderly depressed patients.

Elderly depressed patients who met the Research Diagnostic Criteria (RDC) for major depressive illness, were treated with phenelzine, a non-selective monoamine oxidase inhibitor, for a period of 2 to 7 wk, following 2 wk of placebo washout period. Possible pre- and post-treatment differences on the cognitive test battery were evaluated using the Wilcoxon test. Although recovery from depression was obtained in the majority of patients (Hamilton, Global and Self-rating Scales), none of the cognitive measures showed statistically significant changes over the course of the treatment period and the cognitive tests scores did not change as a result of treatment. It is of interest that tricyclic antidepressants (TCAs) are known to impair memory in geriatric patients, presumably due to their sedative and anticholinergic effects. The lack of an adverse cognitive effect for phenelzine therefore suggests a possible advantage of monoamine oxidase inhibitors over tricyclic antidepressants for the treatment of geriatric depression.

Aged↗
PubMed1983

Resistant geriatric depressions and therapeutic response to monoamine oxidase inhibitors.

Elderly depressed patients who met the research diagnostic criteria (RDC) for major depressive illness, resistant to other types of treatment, were treated with phenelzine, a nonselective monoamine oxidase (MAO) inhibitor, for a period of 2 to 7 weeks, following 2 weeks of placebo washout period. Dosage ranged from 15-75 mg daily. Clinical status of patients as well as vital signs, EKG, and platelet MAO inhibition were measured weekly. All responders at the end of this period were followed for 1 to 2 years. Analysis of the results showed a 65% response rate as measured by Hamilton, Global, and Self-rating Scales. No significant drug effect in cognitive functioning, as measured by objective cognitive tests, was observed. Clinical improvement was sustained for all participants throughout the follow-up period with no side effects. A direct relationship between platelet MAO inhibition and clinical response was found. The majority of the responders (70%) had achieved high platelet MAO inhibition values (greater than 80%), while most of the nonresponders had platelet MAO inhibition values of less than 80%. These findings have potential clinical and research implications for treating geriatric depression, especially the ones resistant to other forms of treatment.

Aged↗