Expression and purification of mammalian calreticulin in Pichia pastoris

Calreticulin is a 46-kDa Ca(2+)-binding chaperone of the endoplasmic reticulum membranes. The protein binds Ca(2+) with high capacity, affects intracellular Ca(2+) homeostasis, and functions as a lectin-like chaperone. In this study, we describe expression and purification procedures for the isolation of recombinant rabbit calreticulin. The calreticulin was expressed in Pichia pastoris and purified to homogeneity by DEAE-Sepharose and Resource Q FPLC chromatography. The protein was not retained in the endoplasmic reticulum of Pichia pastoris but instead it was secreted into the external media. The purification procedures reported here for recombinant calreticulin yield homogeneous preparations of the protein by SDS-PAGE and mass spectroscopy analysis. Purified calreticulin was identified by its NH(2)-terminal amino acid sequences, by its Ca(2+) binding, and by its reactivity with anti-calreticulin antibodies. The protein contained one disulfide bond between (88)Cys and (120)Cys. CD spectral analysis and Ca(2+)-binding properties of the recombinant protein indicated that it was correctly folded.

Pyrrole analogues of chloramphenicol. II. Synthesis and antibacterial activity of DL-threo-1-(1-methyl-5-nitro-pyrrole-2-yl)-2-dichloroacetamidopropane-1, 3-diol

The seven-stage synthesis of a pyrrole analogue of chloramphenicol (VII) was described. The compound exhibits a significant antibacterial activity.

[Biochemical mechanism of raloxifen and tamoxifen action for the prevention of breast cancer. Studies in vitro]

Cancer growth follows fine balance disturbance between cell proliferation, differentiation and death. It has been shown that mutation of 4 to 5 genes controlling cellular proliferation events may be contributive to carcinogenesis. Estrogens play a central role in reproductive physiology. They are also a causative factors in the pathogenesis of neoplastic and non-neoplastic diseases, including breast cancer. The estrogen dependency of human breast cancer has been successfully exploited in the treatment of early and advanced diseases and provides a unique opportunity for chemoprevention of this common malignancy. The aim of present study was to examine the effects of tamoxifen and raloxifen on the induction of apoptosis and proliferative activity of human breast adenocarcinoma MCF-7 cells. It has been found that both tamoxifen and raloxifen decreased the speed of cell cycle in MCF-7 cells and acts as proapoptotic factors. It reduces viability of cancer cells and probability of neoplastic clone multiplification. This effect conducts to limitation of cancer expansion.

Influence of estrogen, antiestrogen and UV-light on the balance between proliferation and apoptosis in MCF-7 breast adenocarcinoma cells culture

Studies of the mechanism of actions of estrogen, antiestrogen and physical factors may provide clues to an understanding of breast cancer growth and/or regression regulation and thus identify novel targets for therapeutic intervention. Defective control of apoptosis appears to play a central role in the pathogenesis of neoplasia. Conversely, cancer therapy and ionizing radiation can induce cancer cell death by apoptosis and/or necrosis. bcl-2 gene and p-53 gene products have been both linked to programmed cell death pathways. We have analyzed the effect of estradiol, tamoxifen and UV exposure on the induction of apoptosis, expression of p53 and bcl-2 gene products as well as the proliferative activity (expressed as [3H]thymidine incorporation and PCNA and MPM2 antigens involvement) in MCF7. It has been found that estradiol increases the speed of cell cycle in MCF7 and acts as antiapoptotic factor. Tamoxifen has multiple influence on the rate of growth of cancer cells: depends on estrogen receptor (ER), conducts reduction of proliferation rate; depends on ER and other mechanisms conducts to suppressions of Bcl-2 protein expression and induction of cell death through apoptotic pathway. Estradiol prevents the apoptotic influence of tamoxifen probably by enhancement of Bcl-2 protein expression and does not prevent the inhibition of proliferation rate. The irradiation with UV induces apoptosis by over-expression of p53 and down-regulation of bcl-2 gene.

Trichinella spiralis and Trichinella pseudospiralis: developmental patterns of enzymes involved in thymidylate biosynthesis and pyrimidine salvage

Thymidylate synthase, dihydrofolate reductase and dUTPase specific activities were found to remain at a high and constant level in crude extracts from adult worms of Trichinella spiralis, as well as from muscle larvae of both Trichinella spiralis (isolated 1-24 months after infection) and Trichinella pseudospiralis (isolated 5.5-13 months after infection). The results obtained with Trichinella pseudospiralis muscle larvae isolated with the use of pepsin did not differ from those obtained when pepsin was not used. No thymidine kinase activity could be detected in muscle larvae of either species and thymidine phosphorylase could be found only in T. pseudospiralis larvae isolated without the use of pepsin. Muscle larvae of both species contained orotidylate phosphoribosyl transferase activity, pointing to a possibility of 5-fluorouracil activation. Uridine phosphorylase, another enzyme involved in 5-fluorouracil anabolism, was also present in T. pseudospiralis muscle larvae. Results of comparative studies on inhibition of purified T. spiralis and rat thymidylate synthases by substrate (4-thio-5-fluoro-dUMP, 2-thio-5-fluoro-dCMP and N4-hydroxy-dCMP) and cofactor (ZD 9331) analogues indicated only dUMP analogues to show feeble selectivity towards the parasite enzyme. A hypothesis is discussed, assuming high expression of thymidylate synthase in muscle larvae to be connected with their cells being arrested in the cell cycle.

Pyrrole analogues of chloramphenicol. I. Synthesis and antibacterial activity of DL-threo-1-(1-methyl-4-nitropyrrole-2-yl)-2-dichloroacetamidopropane-1,3-diol

The seven-stage synthesis of a pyrrole analogue of chloramphenicol [IX] was described. The compound exhibits a significant antibacterial activity, over the 12-50% range of the chloramphenicol activity.

alpha1-microglobulin as a marker of proximal tubular damage in urinary tract infection in children

The urinary alpha1-microglobulin (alpha1-M) as a marker of proximal tubular damage was measured in 86 children, aged 3/12 to 12 years, with a diagnosis of urinary tract infection (UTI) and fever. All patients had normal glomerular filtration rates (GFR). They were divided into 2 groups: A: with UTI and etiological factor E. coli, B: with UTI and etiological factor Proteus sp. Similar measurements of alpha1-M were obtained for a control group of healthy children. An increased mean level serum alpha1-M was observed in patients with UTI and fever compared to control group (p < 0.001). Urinary alpha1-M as the alpha1-microglobulin/creatinine ratio was higher in both tested group of patients with UTI and fever. Those found in group A1 and B1 before treatment were the highest and statistically significantly elevated after treatment (group A2 and B2: p < 0.001). Our results indicate the usefulness of the urinary alpha-microglobulin/creatinine ratio as a marker of proximal kidney tubule damage in children with E. coli and Proteus sp. infections. Additionally, it seems to be associated with the humoral and cellular immune response.

Molecular modelling, synthesis and antitumour activity of carbocyclic analogues of netropsin and distamycin--new carriers of alkylating elements

A series of netropsin and distamycin analogues was synthesised and investigated by molecular modelling. The lowest-energy conformations of four carbocyclic lexitropsins, potential carriers of alkylating elements, were obtained using the HyperChem 4.0 program, and compared with the DNA-lexitropsin crystal structures from the Brookhaven National Laboratory Protein Data Bank. A method for synthesis of carbocyclic lexitropsins was elaborated, with the use of a nitro group or azobenzene as precursors for the aromatic amino group. The influence of methoxy group in ortho position with respect to amide groups on the activity of the new compounds was investigated. All of the compounds tested showed high antitumour activity in the standard cell line of mammalian tumour MCF-7.

The concentration of alpha-1-antichymotrypsin in blood serum of women in labour

Concentration of alpha-1-antichymotrypsin (A-1-ACT) in blood serum of parturient women was determined. The investigation was conducted in 33 women bearing eutrophic newborns and 36 women bearing hypotrophic newborns. The control group consisted of 30 healthy non-pregnant women in reproductive age. Concentrations of A-1-ACT were determined using the radial immunodiffusion method according to Mancini et al. Maximal concentration of A-1-ACT determined in group I was three times higher than minimal concentration. Maximal concentration of A-1-ACT determined in group II was two times higher than minimal concentration. In the control group, the difference between minimal and maximal concentrations of A-1-ACT was inconsiderable. The lack of statistically significant differences between these three groups suggests that labour stress does not influence serum concentrations of this inhibitor. The importance of A-1-ACT in the placental tissue may be connected with immunological mechanisms that assure development and maintenance of pregnancy.

Aryltriazole C-nucleosides with affinity with certain DNA sequences. I. Synthesis of 2-(3-nitrophenyl)-4-(beta-D-erythrofuranosyl)-1,2,3-triazole

The paper describes the synthesis of 2-(3-nitrophenyl)-4-(beta-D-erythrofuranosyl)-1,2,3-triazole. This substance is a key substrate for synthesis of C-nucleosides, having a potential affinity with the G-C base pair.

[The phenotype characteristics of cord blood lymphocytes in premature neonates]

It has been observed high risk of infections in neonates as a result from lymphocytes immaturity. It is connected to phenotype differences of lymphocytes between neonates and adults. This high susceptibility to infections is especially high in premature neonates. With the use of flow cytometry we have evaluated the phenotype of cord blood lymphocytes in premature neonates. In comparison to results of healthy newborns we have observed significant decrease in CD7+, CD3+, CD4+, CD25+, CD57+ lymphocytes an increase in total number of CD8+ cells as well as alteration in CD4/CD8 ratio. Our results suggest deeply damage of cellular immunity in preterm infants.

[Flow cytometry in hematologic diagnosis]

The paper presents flow cytometry method in haematology diagnostics. Beside to the estimation of blast cells phenotype in acute leukaemia, flow cytometry allows to evaluate the presence of minimal residual disease (MRD) and multi drug resistance protein (MDR). Flow cytometry plays a crucial role in the estimation of DNA profile in cancer cells and evaluation of stem cells. Repeatedly flow cytometry is used to estimate platelets and reticulocytes.

[The concentration of alpha-2-antiplasmin in sera of women in post partum]

Alpha-2-antiplasmin is a main inhibitor of plasmin and play a crucial role in regulation of intravascular fibrinolysis. It is important to know, in pregnant women as well in the immediate post partum period the activation of hemostasis takes place and is observed thrombotic incidences. In our studies we have included 33 pregnant women whose delivered eutrophic newborns alpha-2-AP 7.79 mg/dl and 36 pregnant women whose delivered small-for-date newborns, alpha-2-AP 7.49 mg/dl. We found no significant statistically differences between tested groups and in comparison to control group 6.0 mg/dl. The presented results seems to indicate, the determination of concentration of alpha-2-AP in sera of women in immediate post partum period does not reflect the changes in the mechanisms of fibrinolytic system in the course of the partum.

[Antiproteases in the pathogenesis of neoplastic diseases]

The imbalance between proteases and their inhibitors has substantial significance for the pathogenesis of the neoplastic disease. Proteases have been shown to play multiple roles in carcinogenesis and tumor promotion, while antiproteases (PI) can be regarded as anticarcinogenic agents. Hypotheses concerning the mechanism of PI anticarcinogenic action were presented in this article. The estimation of the antiprotease level may be clinically and therapeutically useful in some cases of cancer disease.

Middle superficial cerebral vein

The microanatomical study present the anatomy of the middle cerebral vein. On the basis of the anatomical data we distinguished concentric and nonconcentric types of tributaries of the middle superficial cerebral vein. The nonconcentric type prevails.

[Serine protease inhibitors in newborns. IV. Levels of alpha-2-macroglobulin in serum of eutrophic and hypotrophic newborns and their mothers]

It is accepted that alpha-2-M may serve as an important factor for the regulation of homeostasis. For these reasons it is valuable to determine its concentration in some clinical conditions. We have found that the level of alpha-2-M is evidently higher in hypotrophic newborns than in neutrophic newborns. It is interesting to note that the mothers of hypotrophic newborns also exhibit increased concentration of alpha-2-M in comparison to the mothers of eutrophic newborns. No differences were observed in concentration of this inhibitor between mothers and this newborns in both groups. Taking under consideration these findings it seems there is an inverse relationship between cord serum alpha-2-M concentrations and birth weight of newborns. Probably the increase of this inhibitor may reflect in some extent its function as moderating factor high susceptibility hypotrophic newborns for infections since alpha-2-M plays so crucial role in inflammatory processes.

[Flow cytometric analysis of cord blood lymphocytes]

It has been observed that immunological reactivity of neonatal leukocytes is diminished. It seems to result from lymphocytes immaturity. In the present study we have evaluated the phenotype of cord blood lymphocytes with the use of flow cytometry. In neonates we have observed the increase in the absolute number of CD1a and CD7 positive lymphocytes as well as CD2, CD3, CD4, CD8, CD16, CD19 and CD20 positive, while number of CD57 positive cells was significantly decreased. The ratios of CD4/CD8 and T/B lymphocytes were similar to the corresponding ratios observed in adults. Our results have shown the presence of immature lymphocyte population as well quantitative depletion of subpopulation of CD57 cells, what may pose an increased risk of infection in neonates. Nevertheless, increased number of T and B lymphocytes with mature phenotype along with normal ratio of lymphocyte subpopulations and increased number of CD16 positive cells (NK cells), may explain phenomenon of good health among majority of newborns.

Comparison of oxidative base damage in mitochondrial and nuclear DNA

The levels of endogenous pig liver cells mitochondrial DNA oxidative base damage have been investigated using isotope dilution gas chromatography mass spectrometry (GC/MS). Higher levels of five measured bases were found in mtDNA in relation to nuclear DNA. We have also detected large differences in the modified base ratios of mitochondrial versus nuclear DNA. These ratios for the bases with promutagenic properties as 8OHGua and 5OHCyt are much lower than for other bases (5OHHyd, 5OHMeHyd, 5OHMeUra).

Does the concentration of alpha 1-proteinase inhibitor reflect the transformation of liver cirrhosis to liver carcinoma?

Serum concentration of alpha1-proteinase inhibitor (alpha1-PI) was determined by nephelometric method in forty seven patients with liver cirrhosis (LC) and fifteen patients with hepatocellular carcinoma (HCC). Our data show an increase in the concentration of alpha1-PI in the group with decompensated LC by 17% and in HCC by 29%. The level of alpha1-PI higher than (220 mg%) may be indicative of the disease progression towards decompensated LC or HCC. In the conclusion, an increase in alpha1-PI concentration in patients with LC may be considered as an alarming factor, but is not sufficiently specific to become a diagnostic tool for the detection of HCC development.

A general system for generating unlabelled gene replacements in bacterial chromosomes

A general system is described that facilitates gene replacements such that the recombinant strains are not labelled with antibiotic resistance genes. The method is based on the conditional replication of derivatives of the lactococcal plasmid pWV01, which lacks the repA gene encoding the replication initiation protein. Replacement vectors can be constructed in and isolated from gram-positive and gram-negative helper strains that provide RepA in trans. Cointegrate formation of the integration vectors with the chromosome of the target strain is selected by antibiotic resistance. Resolution of the cointegrate structure is identified in the second step of the procedure by the loss of the lacZ reporter gene present in the delivery vector. The second recombination event results either in gene replacement or in restoration of the original copy of the gene. As no antibiotic resistance marker is present in the genome of the mutant the system can be used to introduce multiple mutations in one strain. A feasibility study was performed using Lactococcus lactis and Bacillus subtilis as model organisms. The results indicate that the method should be applicable to any non-essential gene in numerous bacterial species.

Trichinella spiralis thymidylate synthase: developmental pattern, isolation, molecular properties, and inhibition by substrate and cofactor analogues

Thymidylate synthase specific activity was found to remain at a constant level in crude extracts from muscle larvae, isolated (1-15 months after infection) by pepsin-HCI digestion, as well as from adult worms of Trichinella spiralis. The enzyme was purified and its molecular (monomer mol. wt 35 kD) and kinetic (sequential mechanism with the K(m) values 3.1 and 19 microM for dUMP and N5,10-methylenetetrahydrofolate, respectively) properties determined. 5-Fluoro-dUMP was a competitive, slow-binding inhibitor of the parasite enzyme. N5,10-methylenetetrahydrofolate analogues 10-propargy1-5,8- dideazafolate (CB3717), ZD1694, BW1843U89, and AG337 were weaker inhibitors of the parasite than regenerating rat liver enzyme. Inhibition by 10-propargyl-5,8-dideazafolate was strengthened by an increasing number of glutamate residues. Thymidine kinase activity could not be detected in the muscle larvae crude extracts.

Molecular cloning and nucleotide sequence of the gene encoding the major peptidoglycan hydrolase of Lactococcus lactis, a muramidase needed for cell separation

A gene of Lactococcus lactis subsp. cremoris MG1363 encoding a peptidoglycan hydrolase was identified in a genomic library of the strain in pUC19 by screening Escherichia coli transformants for cell wall lysis activity on a medium containing autoclaved, lyophilized Micrococcus lysodeikticus cells. In cell extracts of L. lactis MG1363 and several halo-producing E. coli transformants, lytic bands of similar sizes were identified by denaturing sodium dodecyl sulfate (SDS)-polyacrylamide gels containing L. lactis or M. lysodeikticus cell walls. Of these clearing bands, corresponding to the presence of lytic enzymes with sizes of 46 and 41 kDa, the 41-kDa band was also present in the supernatant of an L. lactis culture. Deletion analysis of one of the recombinant plasmids showed that the information specifying lytic activity was contained within a 2,428-bp EcoRV-Sau3A fragment. Sequencing of part of this fragment revealed a gene (acmA) that could encode a polypeptide of 437 amino acid residues. The calculated molecular mass of AcmA (46,564 Da) corresponded to that of one of the lytic activities detected. Presumably, the enzyme is synthesized as a precursor protein which is processed by cleavage after the Ala at position 57, thus producing a mature protein with a size of 40,264 Da, which would correspond to the size of the enzyme whose lytic activity was present in culture supernatants of L. lactis. The N-terminal region of the mature protein showed 60% identity with the N-terminal region of the mature muramidase-2 of Enterococcus hirae and the autolysin of Streptococcus faecalis. Like the latter two enzymes, AcmA contains C-terminal repeated regions. In AcmA, these three repeats are separated by nonhomologous intervening sequences highly enriched in serine, threonine, and asparagine. Genes specifying identical activities were detected in various strains of L. lactis subsp. lactis and L. lactis subsp. cremoris by the SDS-polyacrylamide gel electrophoresis detection assay and PCR experiments. By replacement recombination, an acmA deletion mutant which grew as long chains was constructed, indicating that AcmA is required for cell separation.

Serum concentration of alpha-2-macroglobulin, alpha-1-antitrypsin and alpha-1-antichymotrypsin [correction of alpha-2-antichymotrypsin] in patients with Hodgkin's disease

In twenty four patients diagnosed with Hodgkin's disease we have determined several antiproteases. Our findings have shown the decrease of concentration of alpha-2-macroglobulin and increase of alpha-1-proteinase inhibitor and alpha-1-antichymotrypsin. The observed changes were statistically significant p < 0.001. We did not find any correlation between the concentration of inhibitors and the clinical stage of carcinoma and histopathological data. The determination of the level of antiproteases in patients with cancer disease may be assumed to reflect partly at least the capability of anticancer mechanism in the host.

Effect of dimethylsulfoxide-hydroxyl radical scavenger on cerulein-induced acute pancreatitis in rats

Acute oedematous pancreatitis was induced in Wistar male rats by intravenous (i.v.) infusion of cerulein at the rate of 5.10(-6)g.kg-1.h-1 for 3 or 6 hrs. The effects of dimethylsulfoxide (DMSO)-hydroxyl radical scavenger in this model of disease were examined. DMSO was injected i.v., 0.75 g.kg-1, at 0 and 3 hrs during cerulein infusion. Treatment with this agent exerted a protective effect on the rat pancreas in the cerulein-induced acute pancreatitis. This effect is expressed by inhibition of lipid peroxidation in pancreatic tissue, less oedema formation, diminution of hyperlipasemia and a significant reduction in acinar cell vacuolisation. Our data suggest that besides the hydroxyl radical, other oxidants (secondary?) may cause cytotoxicity in this model of disease. We suggest that phagocytic inflammatory cells provide such oxidants.

Opiate-like peptides. Part XIII. Synthesis and analgesic activity of met-enkephalin analogs substituted in position 4 with D-4-halogenophenylalanine

Six met-enkephalin derivatives substituted in position 4 with D-4-chlorophenylalanine or D-4-fluorophenylalanine were obtained. Their antinociceptive activity was determined after icv administration to rats by tail immersion test. Cataleptic activity and the influence of the analogs obtained on the body temperature were also estimated. All compounds exerted analgesic activity, which was decreased significantly by naloxone. Almost all compounds appeared cataleptic, some of them caused hypothermia.

[Proteases and protease antagonists in neoplasms]

The maintenance of equilibrium between proteases and their inhibitors has substantial significance for the pathogenesis of the neoplastic disease. It concerns especially the invasiveness of the neoplasms, which increases with rising of the proteases activity or with the decrease of the inhibitory activity of antiproteases. The neoplastic cell has the faculty of producing numerous proteases which by damaging connective tissue facilitates the invasion by the neoplasm. Invasiveness of the neoplasms may be augmented by the production of proteases by the host cells stimulated by the neoplasm. The condition of the proteases--antiproteases balance is also influenced by the production of antiproteases by neoplastic cells. Among numerous antiproteases alpha-2-macroglobulin has most intensive cytotoxic action in relation with the neoplasm. According to data collected from the literature, antiproteases can be regarded as anticarcinogenic agents. On account of this, the estimation of the antiproteases level can be regarded as a measure of the ability of the body system to resist the invasiveness of neoplasms.

Derivatives of the L-lysine-peptides with antibacterial activity

A number of derivatives of the L-lysine peptides has been obtained and their antibacterial properties were evaluated and compared with those of the ethyl ester of Nalpha-palmitoyl-L-lysyl-L-lysine dihydrochloride. Some correlations have been found between the chemical structure and antibacterial activity of the compounds.