Advances in Understanding Carboxysome Assembly in Prochlorococcus and Synechococcus Implicate CsoS2 as a Critical Component

The marine Synechococcus and Prochlorococcus are the numerically dominant cyanobacteria in the ocean and important in global carbon fixation. They have evolved a CO2-concentrating-mechanism, of which the central component is the carboxysome, a self-assembling proteinaceous organelle. Two types of carboxysome, α and β, encapsulating form IA and form IB d-ribulose-1,5-bisphosphate carboxylase/oxygenase, respectively, differ in gene organization and associated proteins. In contrast to the β-carboxysome, the assembly process of the α-carboxysome is enigmatic. Moreover, an absolutely conserved α-carboxysome protein, CsoS2, is of unknown function and has proven recalcitrant to crystallization. Here, we present studies on the CsoS2 protein in three model organisms and show that CsoS2 is vital for α-carboxysome biogenesis. The primary structure of CsoS2 appears tripartite, composed of an N-terminal, middle (M)-, and C-terminal region. Repetitive motifs can be identified in the N- and M-regions. Multiple lines of evidence suggest CsoS2 is highly flexible, possibly an intrinsically disordered protein. Based on our results from bioinformatic, biophysical, genetic and biochemical approaches, including peptide array scanning for protein-protein interactions, we propose a model for CsoS2 function and its spatial location in the α-carboxysome. Analogies between the pathway for β-carboxysome biogenesis and our model for α-carboxysome assembly are discussed.

Specific binding of glucosaminylmuramyl peptides to histones

Intracellular N-acetylglucosaminylmuramyl peptide-binding proteins of murine macrophages and myelomonocytic WEHI-3 cells were characterized. SDS-PAGE and Western blotting revealed proteins with molecular masses of 18, 32 and 34 kDa retaining the ability to specifically bind glucosaminylmuramyl dipeptide. The inhibition analysis demonstrated that only biologically active muramyl peptides but not inactive analogs or fragments of glucosaminylmuramyl dipeptide could inhibit glucosaminylmuramyl dipeptide-binding to these proteins. Purification of these proteins and sequencing of peptides obtained after in-gel trypsin digestion enabled us to identify the above mentioned proteins as histones H1 and H3. These findings suggest that nuclear histones might be target molecules for muramyl peptides.

A novel gene encoding a sulfur-regulated outer membrane protein in Thiobacillus ferrooxidans

Thiobacillus ferrooxidans is a Gram-negative chemolithotrophic bacterium able to oxidize ferrous iron, elemental sulfur and inorganic sulfur compounds. The oxidation of sulfur by T. ferrooxidans resulted in an expression of some outer membrane proteins (OMPs) at a level higher than that observed during ferrous iron oxidation. Among these OMPs, a protein with a molecular mass of 54 kDa was purified and 18 amino acids of the N-terminal sequence determined. Using a 54 bp PCR generated DNA product as a probe for the protein, we isolated a 4.5 kb Pst I DNA chromosomal fragment containing the corresponding gene. Sequencing 2169 bp of this fragment revealed the open reading frame codifying for the protein, consisting of 467 amino acids and a molecular mass of 49,674 Da. The mature protein was produced by the removal of a 32 amino acid signal peptide-like sequence from the N-terminus of a 499 amino acid peptide. Although no significant homology with any known protein has been found and its physiological role remains unclear, its high expression on sulfur substrates suggests a role in sulfide mineral oxidation.

Shared tumor antigens in colorectal carcinoma and neuroendocrine tumors

ND4 monoclonal antibody recognizes a tumor marker found on poorly differentiated colorectal cancer. We demonstrate its expression in 25% of gastrointestinal neuroendocrine tumors, which also express CEA in 37% of cases. As in colorectal cancer the ND4 marker is predominantly membrane bound in a colonic neuroendocrine tumor cell line, LCC-18 (p < 0.05). The ND4 marker is absent in a poorly differentiated colorectal cancer cell line that does not express CEA or other tumor antigens. Shed antigen in the serum of patients with neuroendocrine tumors is detected in only five of seven patients with the carcinoid syndrome and two of four of those without evidence of the syndrome. However, the reactivity was less in the patients with localized disease, and this test is unlikely to be of diagnostic utility in this group of patients. The sharing of this antigen in colorectal cancer and neuroendocrine tumors is not universal, but does support the common-cell progenitor theory for the origin of these tumors.

Rhodobacter capsulatus genes encoding form I ribulose-1,5-bisphosphate carboxylase/oxygenase (cbbLS) and neighbouring genes were acquired by a horizontal gene transfer

Analysis of the nucleotide sequence of the form I ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) genes (cbbL and cbbS) of the non-sulfur purple bacterium Rhodobacter capsulatus indicated that the deduced amino acid sequence of the large subunit was not closely homologous to the large subunit from related organisms. Indeed, phylogenetic analysis suggested that the large subunit protein (CbbL) more closely resembled the enzyme from alpha/beta/gamma purple bacteria and cyanobacteria and is within a 'green-like' radiation of the RubisCO phylogenetic tree, well separated from CbbL of the related organism Rhodobacter sphaeroides. A cbbQ gene was discovered downstream of cbbS in Rh. capsulatus, a gene arrangement which also appears to be limited to certain organisms containing a 'green-like' RubisCO. Upstream, and divergently transcribed from cbbLSQ, is a gene (cbbRI) that encodes a LysR-type transcriptional activator. Phylogenetic analysis of the deduced amino acid sequence of CbbRI also suggests that this protein is quite distinct from the Rh. sphaeroides CbbR protein, and is even distinct from the previously described CbbRII protein, the gene of which is upstream and divergently transcribed from the cbbII operon of Rh. capsulatus. Interestingly, Rh. capsulatus CbbRI is more closely related to CbbR from bacteria whose RubisCO falls within the 'green-like' radiation of the CbbL tree. These studies suggest that the cbbRI-cbbL-cbbS-cbbQ genes were acquired by Rh. capsulatus via horizontal gene transfer from a bacterial species containing a 'green-like' RubisCO.

The 95-kilodalton membrane glycoprotein overexpressed in novel multidrug-resistant breast cancer cells is NCA, the nonspecific cross-reacting antigen of carcinoembryonic antigen

Human breast carcinoma MCF-7/AdrVp cells display a novel multidrug resistance phenotype that is characterized by the overexpression of a 95-kDa membrane glycoprotein (p95) and by marked reduction in intracellular anthracycline accumulation, without overexpression of P-glycoprotein or the multidrug resistance protein MRP. p95 is also highly expressed in multidrug-resistant NCI-H1688 cells derived from a human small cell lung carcinoma. Deglycoslyated p95 from NCI-H1688 cells was isolated by two-dimensional gel electrophoresis and then digested with trypsin. The tryptic peptides were analyzed by mass spectrometry and microsequencing. These analyses identified p95 to be identical to NCA-90, the nonspecific cross-reacting antigen related to the carcinoembryonic antigen (CEA). Further confirmation that p95 is indeed NCA-90 was obtained by Northern and Western blot studies using probes or antibodies specific for p95, NCA-90, or CEA family members. Western blot studies also revealed that CEA itself is overexpressed in MCF-7/AdrVp cells compared to parental MCF-7/W cells. The enforced expression of NCA-90 protein in HeLa cells stably transfected with NCA-90 cDNA did not result in increased resistance of the transfected cells to daunorubicin or a decrease in daunorubicin accumulation in the transfected cells compared to cells transfected only with the expression vector. However, a recent report by H. Kawaharata et al. (Int. J. Cancer, 72: 377-382, 1997) of diminished accumulation, retention, and cytotoxicity of doxorubicin in EJNIH3T3 cells in which enforced expression of CEA was accomplished leaves open the possibility that the overexpression of CEA, possibly in combination with that of NCA-90, could account at least in part for the drug resistant phenotype displayed by MCF-7/AdrVp cells.

Neuropeptide Y 3-36 is an endogenous ligand selective for Y2 receptors

Neuropeptide Y (NPY 1-36) binds to Y1 and Y2 receptors with similar affinity. No endogenous molecular form of NPY with selectivity for Y1 or Y2 receptors has been described so far. We report the presence of an endogenous fragment of NPY in porcine brain, NPY 3-36, which lacks the amino-terminal dipeptide Tyr-Pro of NPY 1-36. NPY 3-36 accounts for 35% of NPY-like immunoreactivity in porcine brain. We have compared binding of NPY 3-36 and NPY 1-36 in model systems of Y1-like (SK-N-MC cells) and Y2-like receptors (CHP234 cells). NPY 3-36 and NPY 1-36 had similarly high affinity for Y2-like receptors on CHP234 cells, but NPY 3-36 had a 1000-fold lower affinity than NPY 1-36 for Y1-like receptors on SK-N-MC cells. Thus amino-terminal cleavage of NPY 1-36 generating NPY 3-36 converts an unselective Y1/Y2 receptor ligand into a highly Y2 selective ligand. This may be a means of fine tuning NPY biological actions.

Breast-tumor xenograft targeting and therapy studies using radiolabeled chimeric anti-cea monoclonal-antibody t84.66

Carcinoembryonic antigen (CEA) is expressed in approximately 60% of breast carcinomas. T84.66 is a well characterized anti-CEA murine monoclonal antibody (MAb) that does not cross-react with other CEA-related proteins. It has been humanized and used extensively after radiolabeling in clinical/experimental protocols for localization/therapy of colorectal cancer. MCF-7 human breast cancer cell line expresses CEA and is tumorigenic in athymic mice. In order to determine if anti-CEA MAb could specifically target breast cancer CEA, biodistribution, radiolocalization and therapy studies were performed in the animal model. Five tumor-bearing animals per time point were injected with 15 muCi of In-111-cT84.66. Mice were imaged and sacrificed at 24, 48, 72 and 144 h and biodistribution studies performed. For therapy studies, 19 tumor-bearing mice were injected either with 120 muCi of 90Y-cT84.66 or PBS. The tumors were measured tri-weekly and weighed at autopsy 21 days post therapy. Activity accumulation steadily increased in the tumors reaching 21% of the injected dose per gram of tumor (ID/g) at 144 h. At that time, the %ID/g in the tumor was 3 times higher than that in blood and the liver and 8 times higher than in other major organs. On day 10 post-therapy, 16 of the 19 control mice had tumor volumes between 1 and 3 cm3, while none of the treated tumors ever reached 1 cm3 in size. At autopsy, a 12-fold tumor weight difference (p=0.0001) was observed between control and treated mice (2.4g vs. 0.2g average weight, respectively). In summary, breast cancer CEA was specifically targeted with T84.66 allowing good tumor localization as well as significant tumor growth inhibition. Given the significant expression of CEA in breast cancer, this tumor should be included into the CEA-expressing malignancies for targeting with anti-CEA MAbs.

Characterization of two forms of peptide YY, PYY(1-36) and PYY(3-36), in the rabbit

Peptide YY (PYY) has been purified as a 36 amino acid peptide from intestinal extracts of several mammalian species including pig, rat, dog, and man. The primary structure of rabbit PYY is still unknown, although rabbit tissues have extensively been used for characterization of PYY receptor subtypes and receptor subtype-mediated actions. We report the purification and primary structure of PYY(1-36) (PYY-I) from rabbit intestinal mucosa, and the existence of a second endogenous molecular form of PYY, PYY(3-36) (PYY-II). The amino acid sequence of PYY-I is YPSKPEAPGEDASPEELNRYYASLRHYLNLVTRQRY-amide. Rabbit PYY differs from porcine PYY, which is identical to rat and canine PYY, by two amino acid substitutions at positions 3 (Ser instead of Ala) and 18 (Asp instead of Ser), whereas rabbit PYY and human PYY differ by only one residue at position 3 (Ser instead of Ile). The existence of two endogenous forms of PYY in the rabbit, with PYY-II lacking the amino-terminal dipeptide Tyr-Pro of PYY-I, is consistent with previously reported findings, demonstrating the existence of PYY-II in man and dog (9,11). We have previously demonstrated that PYY-I is an unselective Y1/Y2 agonist, whereas PYY-II is a highly selective Y2 agonist. Thus, proteolytic processing of PYY-I controls the peptide's receptor selectivity. The existence of PYY-I and PYY-II in the rabbit supports the assumption of a physiological role of Y receptor heterogeneity for PYY.

Intrathecal morphine in younger patients for postoperative pain following spinal fusion

Intrathecal morphine in an average dose of 0.01 mg/kg was given to 33 patients between ages 11 and 16 years who had spinal arthrodesis for idiopathic scoliosis. The morphine was administered intrathecally as a 10 cc bolus at the conclusion of the arthrodesis, but before closure. The goal was to study safety in terms of respiratory depression and pain relief. Respirations occurred spontaneously in 30 of the 33 patients within 15 minutes of cessation of anesthesia. Respiratory depression occurred in five patients, four of whom had arterial blood pCO2 levels greater than 60 mm Hg. Thirty-one patients had relief of pain for 8 to greater than 40 hours, averaging 18 hours. Two patients had no noticeable pain relief. There appeared to be no relation between dose and pain relief in this limited dose range. We were unable to duplicate the long duration of pain relief reported elsewhere. We also were unable to decrease the side effects of respiratory depression and nausea to a level reported by others. It may be that the 10 cc bolus injected intrathecally circulates to the brain and ventricles faster than desired, or that factors relating to type of anesthesia or dose need to be considered. Low-dose intrathecal morphine does provide noticeable pain relief in younger patients undergoing spinal fusion. The side effects of nausea and respiratory depression can be managed safely with medication.

Intrathecal morphine: dosage and efficacy in younger patients for control of postoperative pain following spinal fusion

Intrathecal morphine in an average dose of 0.01 mg/kg was given to 33 patients between ages 11 and 16 years who had spinal arthrodesis for idiopathic scoliosis. The morphine was administered intrathecally as a 10-cc bolus at the conclusion of the arthrodesis, but before closure. The goal was to study safety in terms of respiratory depression and pain relief. Respirations occurred spontaneously in 30 of the 33 patients within 15 minutes of cessation of anesthesia. Respiratory depression occurred in five patients, four of whom had arterial blood pCO2 levels greater than 60 mm Hg. Thirty-one patients had relief of pain for 8 to greater than 40 hours, averaging 18 hours. Two patients had no noticeable pain relief. There appeared to be no relation between dose and pain relief in this limited dose range. We were unable to duplicate the long duration of pain relief reported elsewhere. We also were unable to decrease the side effects of respiratory depression and nausea to a level reported by others. It may be that the 10 cc bolus injected intrathecally circulates to the brain and ventricles faster than desired, or that factors relating to type of anesthesia or dose need to be considered. Low-dose intrathecal morphine does provide noticeable pain relief in younger patients undergoing spinal fusion. The side effects of nausea and respiratory depression can be managed safely with medication.

Biochemical and cytogenetic studies of human lung cancers

In ongoing studies, we have tested resected lung cancers from 41 men and 49 women; of those with primary lung cancer, 46 patients are free of disease and 35 have died of cancer or have persistent disease. Measurements and studies were as follows: total cellular deoxyribonucleic acid content by image analysis (n = 77); total genomic deoxyribonucleic acid methylation state and banding patterns from probed Southern blots (n = 36); radioimmunoassay for motilin, bombesin, gastrin, vasoactive intestinal peptide, and cholecystokinin (n = 18); and cytogenetic analysis (n = 39). All lung cancers were hyperploid. Adenocarcinomas and epidermoid carcinomas were generally hexaploid to nearly septaploid; comparisons by stage and histologic features suggested potential prognostic correlations. There was general hypomethylation of deoxyribonucleic acid (p less than 0.001). Deoxyribonucleic acid digests from restriction endonuclease Hpa II, when probed with deoxyribonucleic acid homologous to KPN, showed banding patterns that separated histologically indistinguishable primary adenocarcinomas and metastatic adenocarcinomas from one another. Cancers studied with radioimmunoassay were all negative for polypeptide hormones. Five cancers grew adequately in vitro to permit study of 190 detailed karyotypes (20 to 50 per tumor). Chromosome modal numbers ranged from 49 to 109. There were from 4 to 20 clearly abnormal marker chromosomes per tumor; abnormality derived from chromosome 1 was prevalent. Ten of 19 tumors xenotransplanted to nude mice were carried through two to five transplant generations without a change in histologic patterns.

Bacterial challenge study of a porous carbon percutaneous implant

Numerous percutaneous devices for power transmission and control to electrically powered, intracorporeal blood pumps have been used for periods ranging from 12 months to 4 yrs; however, consistent and reliable performance has not been achieved, due most frequently to the development of infection and sinus tracts at the percutaneous lead exit site. The present study showed that percutaneous devices fabricated from porous vitreous carbon can function satisfactorily in vivo over extended periods. The implant sites successfully resisted infection by normal flora bacteria for as long as 48 months, although superficial surface colonization and infection did occur after deliberate application of pathogens.

An ultrasound window to perform scanned, focused ultrasound hyperthermia treatments of brain tumors

A series of calculations and tests were performed on polyethylene, polystyrene, acrylic, and a commercially available polymethyl methacrylate cranioplastic to determine which material would best serve as an acoustical window in the skull. The purpose of the window is to transmit focused ultrasound to treat brain tumors with hyperthermia. Each material was evaluated based on its ability to transmit power and to protect the brain. The results revealed that, of the four materials tested, polyethylene transmitted the largest percentage of incident power and is the toughest and best suited material to protect the brain. Further physical tests showed that a polyethylene plate does not significantly distort the sound field. Finally, acute and chronic dog tests (supported by theoretical calculations) using the polyethylene as an acoustical window through the skull showed that it will not reach temperatures greater than the target hyperthermia temperature (42 degrees C) at the required intensity levels unless the tumor is near the skull and the skin surface is not cooled. Since polyethylene effectively transmits power without distorting the sound field of overheating in dog tests, it may now be used in Phase 1 clinical ultrasound hyperthermia tests on human patients. However, the chronic animal studies indicated that the collagen which composes the dura thickens under the cranioplasty and absorbs increasingly greater amounts of power with time. A thick layer of organized fibrous tissue also formed on the external surface of the cranioplasty, filling in the cavity formed by the exterior surface of the cranioplasty and by the excision of the temporalis muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

CCK-5: sequence analysis of a small cholecystokinin from canine brain and intestine

The purpose of this study is to purify and to characterize chemically cholecystokinin (CCK)-like peptides present in brain and gut extracts that elute from gel filtration after the octapeptide. Canine small intestinal mucosa and brain were boiled in water and then extracted in cold trifluoroacetic acid, and cholecystokinin-like immunoreactivity was determined by carboxyl-terminal specific radioimmunoassay. Gel permeation chromatography on Sephadex G-50 revealed a form of CCK apparently smaller than CCK-8. This peptide was purified by immunoaffinity chromatography and three successive reverse phase high-performance liquid chromatography steps. Microsequence analysis showed that the amino terminal primary sequence of this small CCK was Gly-Trp-Met-Asp. Immunochemical and chromatographic analysis indicated that the carboxyl-terminal residue was Phe-NH2 and thus the full sequence is Gly-Trp-Met-Asp-Phe-NH2. An antibody that recognizes synthetic CCK-8, CCK-5, and CCK-4 equally did not reveal the presence of significant amounts of CCK-4. These results indicate that CCK-5 is the major CCK form smaller than the octapeptide present in brain (19% of total CCK immunoreactivity) and small intestine (7% of total). This finding, coupled with the demonstration by others that CCK-5 interacts with high-affinity brain CCK receptors, indicates that CCK-5 may play a physiological role in brain function.

Results of modified Bristow procedure

A modified Bristow procedure was performed on 23 patients over a two-year period. The modification consisted of splitting the subscapularis muscle in line with its fibers and attaching the coracoid process to the neck of the scapula with a malleolar screw. The results were evaluated by questionnaire, physical examination, and radiographs. The average age of the patients was 24 years. There were 20 men and three women. The patients presented 16 left shoulders and seven right shoulders; nine were dominant. The number of previous dislocations was 12. The average follow-up period was 25 months and the average hospital stay was two days. There were no blood transfusions. Each patient returned to his or her preoperative activity level; no patient had pain in the shoulder at rest. With overhead activity, five patients had some pain and 18 had none. Of the nine patients whose surgery was on the dominant side, only two had difficulty in throwing. There were no postoperative recurrent dislocations. There was an average loss of external rotation of 13 degrees and an average loss of internal rotation of 12 degrees. Bony fusion of the coracoid to the neck of the scapula occurred in only one out of 13 shoulders. Complications were minor and resolved completely. The advantages of the procedure are good surgical exposure, minimal tissue trauma, insignificant blood loss, and fewer days in the hospital per patient. The procedure was relatively safe and generally effective.

A novel active pentapeptide from chicken brain identified by antibodies to FMRFamide

The tetrapeptide Phe-Met-Arg-Phe-NH2 (FMRFamide) and peptides structurally related to it, have been isolated from molluscan ganglia. They have widespread actions on both invertebrate and vertebrate tissues and there is increasing evidence that they are an important group of invertebrate peptide neurotransmitters. It is of interest that the primary amino acid sequence of FMRFamide forms the C-terminal tetrapeptide of an enkephalin-like heptapeptide (Met-enkephalin-ArgPhe) isolated from bovine adrenal medulla and striatum. Antisera to FMRFamide have been shown to react in radioimmunoassay and immunohistochemistry with material in the central nervous system of various vertebrate species, but the identity of this material, and in particular its relationship to the opioid heptapeptide, remains uncertain. We have used antibodies specific for the C-terminus of FMRFamide in radioimmunoassays to monitor purification of the material in chicken brain. We describe here the sequence of one of the peptides obtained. It is a biologically active peptide which does not seem to be related to other known vertebrate neuropeptides.

Confirmation of the primary structure of thymosin alpha1 by microsequence analysis of limited acid and enzymatic hydrolysis fragments

The primary structure of the 28-peptide thymosin alpha 1 as determined by Goldstein et al. (1) has been confirmed by independent procedures. Limited dilute acid digestion generated a 26-peptide and a 22-peptide both extending to the C-terminal and lacking the N-terminal blocking group. A combination of Edman microsequencing, carboxypeptidase Y and thermolysin digestion, and fast atom bombardment mass spectrometry was used.

Amino acid sequence of a human leukocyte interferon

The primary structures of three major species of human leukocyte interferon differ from the structure predicted from the DNA sequence of recombinants containing leukocyte interferon-coding regions. Compared to the recombinant interferon produced in bacteria, three of the purified natural proteins isolated from leukocytes lack the 10 COOH-terminal amino acids suggested by the DNA sequence.

Properties of a human alpha-interferon purified from E. coli extracts

A human alpha interferon, designated HuIFN-alpha A, produced in E. coli by direct expression of cloned cDNA [Goeddel et al., Nature 287, 411--416 (1980)] has been purified from bacterial extracts and characterized. The protein has a molecular weight (19,400 by SDS/PAGE) and amino acid composition consistent with the DNA sequence. The pI was determined to be 6.1. The molecule has a specific activity of 1.5 x 10(8) NIH reference units/mg of protein. The sequence of the first 35 amino acids is identical to that expected from the nucleotide sequence. About 50% of the molecules begin with the expected cysteine, and 50% begin with the initiator methionine which E. coli apparently did not remove efficiently. Analysis of a trypsin digest of the native molecule showed that all four of the molecule's cysteines are involved in disulfide bonds: Cys1 is bonded to Cys98, and Cys29 is bonded to Cys 138.

NH2-terminal amino acid sequence of human fibroblast interferon

The purification of human fibroblast interferon by chromatography on Blue Sepharose and high-performance liquid chromatography is described. The amino acid composition and a partial sequence of the homogeneous protein are reported. The NH2 terminus was determined to be NH2-Met1-Ser-Tyr-Asn-Leu-Leu-Gly-Phe-Leu-Gln-Arg-Ser-Ser-Asn-Phe-Gln-X-Gln-Lys.

Amino-terminal amino acid sequence of human leukocyte interferon

We report the amino-terminal sequence of the first 22 amino acids of human leukocyte interferon. These and other results indicate that human leukocyte interferon consists of many individual species. We, therefore, postulate that diversity in this protein is routinely present and that the human leukocyte interferons represent a multigene family.