Effects of dietary supplementation of different levels of vitamin B12 on the liver metabolism of laying hens

BACKGROUND

Vitamin B₁₂ plays an important role in lipid, protein, carbohydrate and nucleic acid metabolism. We investigated the effect of supplementing layers' diets with different vitamin B₁₂ levels on liver metabolism using a liquid chromatography-mass spectrometry-based metabolomic approach to observe and analyse wide-target metabolomics in the liver.

RESULTS

We assigned hens to three groups, namely blank control group without vitamin B₁₂ diet (BCG), normal control group with 25 μg kg^-1 vitamin B₁₂ (NCG) and vitamin B₁₂ supplement group I with 100 μg kg^-1 vitamin (VBSG I). The VBSG I group layers had higher (P < 0.05) vitamin B₁₂ concentration than those from other groups. The egg yolk vitamin B₁₂ concentration increased (P < 0.01) with the increasing vitamin B₁₂ dietary supplemental level. Between the NCG versus BCG, VBSG I versus BCG, and VBSG I versus NCG groups, 11, 20 and 11 metabolites were significantly changed, respectively. The KEGG pathway of vitamin B₆ metabolism was significantly impacted in the NCG layers than those from BCG; seven and five pathways were significantly impacted in the VBSG I layers compared with those from BCG and NCG, including pyrimidine metabolism, vitamin B₆ metabolism, glycerophospholipid metabolism, etc. CONCLUSION: We concluded that 25 μg kg^-1 vitamin B₁₂ supplementation in corn-soybean meal-based layer diet increased the egg yolk vitamin B₁₂ concentration and impacted the vitamin B₆ metabolic pathway, and 100 μg kg^-1 of it increased the egg yolk and liver vitamin B₁₂ concentrations and impacted vitamin B₆ , lipid, nucleic acid and amino acid metabolic pathways. © 2022 Society of Chemical Industry.

Spectrophotometric determination of lamotrigine in pharmaceutical preparations and urine by charge-transfer complexation

Rapid and sensitive spectrophotometric methods are developed for the determination of lamotrigine (LTG) in pharmaceutical dosage forms and urine samples, based on the formation of the charge-transfer (CT) complexes between LTG as an n-donor and the acceptors: bromocresol green (BCG), bromocresol purple (BCP), and chlorophenol red (CPR). These complexes are studied spectrophotometrically in chloroform solution in order to obtain some information about their stoichiometry and stability of complexation. The analytical parameters and their effects on the extraction of drug from urine samples are investigated. The reactions were extremely rapid at room temperature, and the absorbance values remained unchanged after 24 h for all reactions. Beer's law was obeyed in the concentration ranges 0.15-19.8, 0.15-19.8 and 0.05-34.1 microg x ml(-1) for CPR, BCP and BCG, respectively. The proposed methods were applied successfully for the determination of LTG in pharmaceutical formulations, and human urine samples in the presence of other antiepileptic drugs such as carbamazepine, oxcarbazepine and phenobarbital, with good accuracy and precision.

Epitope-tagging vectors for the expression and detection of recombinant proteins in mycobacteria

New tools are required to study the growing number of uncharacterised genes derived from genome sequence projects that are specific to bacterial pathogens such as Mycobacterium tuberculosis. We have developed a series of vectors that permit the specific detection of recombinant proteins expressed in mycobacterial species. Gene expression in these vectors is driven by the strong hsp60 promoter of Mycobacterium bovis BCG and detection of expressed products is facilitated by C-terminal fusion of residues 409-419 of the human c-myc proto-oncogene. Using the M. tuberculosis Ag85B as a reporter of gene expression, we demonstrate that the vectors permit the specific detection of recombinant products expressed in the host species M. bovis BCG. BCG over-expressing Ag85B was a potent inducer of Ag85B-specific T cells in immunised mice, indicating that the C-terminal c-myc tag did not alter the characteristics of the recombinant protein. The versatility of the epitope-tagging vectors was demonstrated by the efficient secretion and detection of recombinant products in BCG. The vectors described in this study will facilitate the expression of foreign proteins in mycobacterial host systems.

[Examination of protein MPB 70 properties in BCG substrains used for the production of Polish antituberculosis vaccines]

The aim of the study was examination of MPB70 protein production by different BCG substrains and testing this protein as reagent in allergenic skin test on BCG vaccinated guinea pigs. Three BCG substrains: Danish 1331 (D), Japanese 172 (J) and Polish BCG Moreau (P) were used for the study. The protein MPB70 received from dr Nagai from Osaka University was used as reference preparation. It has been shown that MPB70 protein of molecular weight about 21,500 Da was present only in BCG Moreau (P) and Japanese (J) substrains. In immunoblotting test monoclonal antibodies reacted additionally with 43,000 Da protein in all tested substrains. We suspect that the detected additional molecule was a dimer of MPB70 protein. The development of skin reactions to MPB70 protein was seen in guinea pigs vaccinated with J and P substrains. The peak of alergy to MPB70 protein was observed 9 weeks after vaccination. In sera of vaccinated animals antibodies against MPB70 protein were detected by ELISA method. The possibility of using MPB70 protein for diagnostic purpose is discussed.

Cell mass of Mycobacterium bovis BCG estimated by gas chromatography

The presence of additives and large cellular aggregates in freeze-dried BCG vaccines precludes accurate measurement of total cell content by traditional methods. The possibility that extraction and quantitation of a cell membrane fatty acid may provide a suitable means of cell mass determination was tested. The palmitic acid methyl ester peak area determined by gas chromatography was directly proportional to the wet weight of freshly grown Tice-, Pasteur-, and Glaxo-substrain BCG, as well as the dry weight of the ampoule contents after removal of soluble material. Extraction of palmitic acid from Tice BCG vaccine was not appreciably affected by lyophilization and the calculated dry cell mass values of freeze-dried vaccine samples correlated well with particle number. This method, therefore, may be useful in measuring BCG cell mass during all stages of vaccine manufacture and storage.

Experimental research on utilization of bioluminescent technique to substitute the current viability count for BCG vaccine

The possibility of using the bioluminescent (BL) technique to substitute the traditional viability count of colony forming units (CFU) of BCG vaccine was investigated. The results showed there is a significant dose-dependent correlation between the concentration of standard adenosine triphosphate (ATP) and ATP BL value. The ultrasonic-chloroform method designed by us yielded the best results. The correlation coefficient values (r) of BL of the liquid and lyophilized vaccine were found to be 0.8 155 and 0.8 484 respectively (P less than 0.05). The coefficient of variation (CV) between the BL value of different lots of ATP obtained was 3.2-4.4%, much lower than that of CFU (CV = 10.4-11.2%). The presence of bacterial clumps within the vaccine had great influence on the bacterial ATP value and on the CFU viability count. 2.8 fg of ATP was found in each CFU formed in the vaccine with clumps, while it was only 0.94 fg in the vaccine without clumps, indicating the superiority of the BL method. The BL method has shown a high sensitivity, good reproducibility and simplicity in handling with quick results and high accuracy. Therefore, we consider that the BL method can be used to substitute the CFU method.

Size characterization of Mycobacterium bovis BCG (Bacillus Calmette Guérin) vaccine, Tice substrain

Reconstituted, lyophilized, attenuated Mycobacterium bovis, Bacillus Calmette Guérin (BCG) vaccine, Tice substrain, was characterized using a Coulter Multisizer and a HIAC/Royco counter. The primary organism has an equivalent spherical diameter approximating 1 micron but the BCG cell suspension is heavily aggregated. The cumulative size distribution of the suspension fits a log-probit plot and this information can be used to determine the total number of particles per ampoule. The instrumental count may be related to the viable count. The state of dispersion was unaffected by mild shear (syringe aspiration or ultrasound) and only slightly affected by the addition of cetylpyridinium chloride or sodium tauroglycolate.

Antitumor activity of the DNA fraction from Mycobacterium bovis BCG. II. Effects on various syngeneic mouse tumors

MY-1, a fraction extracted from BCG and composed of 70.0% DNA and 28.0% RNA, was examined for its antitumor activity against 9 different syngeneic mouse tumors. Tumor regression was induced in almost all of the mice bearing any of five kinds of solid tumors by repeated intralesional injections of 100 micrograms MY-1. When cells of some tumors were inoculated intradermally together with MY-1, tumor growth was suppressed, lung metastases were inhibited, and the survival times of mice bearing 1 of 3 leukemic tumors were prolonged. Repeated sc injections with MY-1 in sites remote from tumor cell inoculation or repeated iv injections were more or less effective against three kinds of solid tumors. Mice inoculated with Lewis lung carcinoma cells in a hind footpad and whose legs were amputated 9 days later were given iv or sc injections of MY-1 every other day (8 times in total), resulting in substantial prolongation of survival. No direct cytotoxicity of MY-1 for these tumors could be shown in three kinds of experiments, which indicates that the antitumor mechanism of MY-1 is host mediated. MY-1 was equally effective in mice with or without presensitization with BCG, whereas BCG was much more effective in BCG-sensitized mice. This finding suggests that a delayed-type hypersensitivity reaction elicited by BCG protein is not required for the antitumor activity of MY-1.

Antitumor activity of deoxyribonucleic acid fraction from Mycobacterium bovis BCG. I. Isolation, physicochemical characterization, and antitumor activity

A fraction extracted from Mycobacterium bovis strain BCG, which was composed of 70.0% DNA, 28.0% RNA, 1.3% protein, 0.20% glucose, and 0.1% lipid and of no detectable amounts of cell wall components such as alpha, epsilon-diaminopimelic acid and hexosamine, was found to possess strong antitumor activity. Repeated intralesional injection of this fraction, designated MY-1, without attachment to oil or a single intralesional injection of MY-1 emulsified in mineral oil caused the IMC carcinoma of CDF1 mice and line 10 tumor of strain 2 guinea pigs to regress and/or prevented metastasis very effectively. MY-1 after digestion with RNase, which contained 97.0% single-stranded DNA with a guanine-cytosine content of 69.8%, was more effective than undigested MY-1 against IMC and line 10 tumor, while MY-1 digested with DNase, which contained 97.0% RNA, had reduced activity, suggesting that the DNA from BCG possessed strong antitumor activity under certain conditions. Details of the extraction procedures and physicochemical characterization of MY-1 were also described.

A comparison of the rate of oxygen uptake and the adenosine triphosphate content of routine and experimental BCG preparations

The ATP content and oxygen uptake rate, two parameters of viability of a BCG suspension, are compared. The lack of correlation between measurements made on fresh routine preparations indicates that the ATP measurements is affected by the degree of dispersion of the preparation. Experimental preparations made under standard conditions (constant semi-dry weight and stepwise dispersive grinding) from cultures of the same age as the fresh routine cultures (14 days) had a smaller ATP content, which correlated well with the respiration rate. In experimental preparations from seven-day cultures this correlation was significant. Between days 7 and 14 the ATP content declined much more rapidly than the respiration rate.

Viability, heat stability and immunogenicity of four BCG vaccines prepared from four different BCG strains

Four BCG strains, French 1173-P2, Danish 1331, Japanese 172 and Glaxo-1077, among those most widely used throughout the world for tuberculosis vaccination, were prepared according to the respective conditions in each BCG-production unit. These 16 vaccine preparations were distributed and compared using standardized in vitro and in vivo conditions, based on optical density and bacillary mass/ml. The results presented in this report concern only the 4 freeze-dried BCG strains prepared by the Institut Pasteur BCG unit. It is shown that these 4 preparations differ in their in vitro characteristics such as growth, morphology, heat stability and viability, tested by colony-forming units and the ATP content. In addition, statistically significant differences were observed in biological control tests performed in guinea-pigs and mice when they were immunized with the same concentrations of 4 reconstituted vaccines. For instance, in tests measuring hallmarks of cell-mediated immunity--such as local granuloma formation, spleen index, delayed-type hypersensitivity to tuberculin, and non-specific immunopotentiation to unrelated antigen--a ranking order of relative immunopotency of the four strains was made, giving the following classification in decreasing order: French 1173-P2, Danish 1331, Japanese 172 and Glaxo-1077. Specific acquired resistance after BCG vaccination in mice was obtained with all four vaccines. However, higher protection was observed in mice vaccinated with Glaxo-1077 and French 1173-P2 strains. No obvious correlation existed between the intensity of cellular post-vaccination resistance and the above CMI tests, except those concerning the three-week index of BCG infection measured in the spleen, which correlated with the protection test.

Mycobacterial carrier and antitumour activity of the combination: BCG-cyclophosphamide

Immuno-chemical studies of various BCG components show that the anti-tumour effect of BCG plus cyclophosphamide is attributed to the interaction between two bacterial fractions and the cytotoxic drug, cyclophosphamide(CY). One of the bacterial fraction is a chemically-well-defined peptidoglycopeptide fraction(PGLF) with immuno-stimulating activity and the other is a bacterial residue (BR) completely devoid of immuno-stimulating activity. Nevertheless, BR, a powerful adsorbant, was found to be a "mycobacterial carrier" of both the active bacterial molecule (PGLF) and the cytotoxic drug (CY).

Chemical and biological properties of subfractions of hot-water extract from delipidated BCG

a hog-water extract from delipidated Mycobacterium bovis strains BCG was fractionated by precipitation with ethanol. The chemical and biological properties of the subfractions thus obtained were investigated. A subfraction precipitated at 20% ethanol contained less neutral sugar and more ninhydrin-positive substance than other subfractions. Only the guinea pigs that were treated with 20% ethanol-precipitate showed no humoral antibody response to egg white albumin, despite positive skin reaction. The subfractions precipitated at low concentrations of ethanol exhibited a significant antitumor activity in ddY and C3H He mice inoculated intraperitoneally with tumor cells. These results suggest that the hot-water extract from delipidated BCG consists of subfractions with different chemical and biological properties.

Induction of antituberculous immunity by polysaccharidic contaminants of crude ribosomal vaccines isolated from Mycobacterium bovis, strain BCG

Crude ribosomal fractions isolated from the BCG strain of Mycobacterium bovis are capable of inducing antituberculous immunity in CF-1 mice. These crude preparations contain varying amounts of polysaccharides in addition to ribosomal ribonucleic acid and proteins. Whereas these latter two constituents of the crude fractions were found inactive, high levels of antituberculous immunity were induced by a ribosomal sub-fraction significantly enriched with polysaccharides. These results strongly suggest that polysaccharides play an important role in the induction of antituberculous immunity in CF-1 mice immunized with crude ribosomal fractions isolated from the BCG strain and that if ribosomal proteins and/or RNA are of a certain importance, their role would be secondary (complexes providing physical support to polysaccharides, adjuvant, etc.).

Report on results of a collaborative assay of BCG vaccines organized by the International Associaton of Biological Standardization

In a collaborative assay initiated by the International Association of Biological Standardization 13 laboratories investigated the properties of 10 freeze-dried BCG vaccines made in different ways by different producers which met the requirements of the World Health Organization. The in vitro tests with respect to the dry weight of the bacteria, the number of culturable particles and the stability during storage at 37 degrees C gave results which showed statistically significant differences between vaccines as well as between laboratories. The use of a reference vaccine in the tests for the number of culturable particles did not improve the precision of the results. These tests are useful as in-process tests to assure the producer that his vaccine will consist of the required amount of bacteria of which a high percentage is living. It was found that all vaccines had a survival of more than 25% after 1 month at 37 degrees C with the exception of two vaccines in rubber-stoppered vials. The two in vivo tests, determining skin reactivity in guinea-pigs and multiplication of BCG in spleens of mice, resulted in nearly the same ranking of the vaccines with respect to their virulence, differing from that of the in vitro tests. In the skin reactivity test the simultaneous injection of both the reference vaccine and a test vaccine into the same animal achieved the elimination of the inter-laboratory variation of the results.

Preservation of mycobacterial suspensions at -55 degrees C

Suspensions in dilute Sauton's medium of 14 mycobacterial strains grown under identical conditions were prepared with bacilli harvested at their midlog phase of growth,and were frozen and stored at -55 degrees C. Survivals, estimated by CFU determinations after periodic intervals of storage, showed no adverse effect of freezing and thawing on any of the strains. Effectiveness of preservation, however, varied from strain to strain and no correlation existed between effectiveness and species of mycobacteria. No noticeable changes in the virulence of the H37Rv strain and in the immunizing activity of BCG were detected after prolonged storeage. Results of experimentsperformed with two strains suspended in seven diluents suggest that some are more suitable for long-term preservation, particularly so for the more sensitive one.

Quantitative evaluation of the effectiveness of Connaught freeze-dried BCG vaccine in mice and in guineapigs

Although the field trials carried out by the Medical Research Council of Great Britain demonstrated that BCG vaccination can confer a substantial degree of immunity against tuberculous infection, it does not follow that BCG substrains other than the one used for those trials will produce equally favourable results. In fact, there is increasing evidence that different BCG strains may differ widely in their protective potency. The experiments described here further confirm these differences. They also show how the determination of the minimum dose of a BCG vaccine capable of delaying the development of tuberculous infection in mice and in guinea-pigs can yield reproducible data that may help to characterize individual BCG strains.The main purpose of these experiments was to determine the protective potency of Connaught freeze-dried BCG vaccine, lot 140, and to compare it with that of three other BCG vaccines. Marked differences were found with respect to the minimum protective dose for mice or guinea-pigs and the degree of immunity and tuberculin allergy produced in guinea-pigs as shown by the dose-response relationships recorded over a wide dosage range. The results suggest that the Connaught vaccine equals or surpasses the other vaccines in effectiveness.Such tests require a reference BCG vaccine of high protective potency for both animals and man.

The lipid substances and cytopathic effects in man of BCG strain "Copenhagen" and attenuated vole bacillus strain "Prague"

Both virulent and attenuated acid-fast micro-organisms (including BCG) may provoke in the infected or vaccinated host cytopathic effects characterized by the formation of specific granulation tissue or caseous necrosis. The mycobacterial antigens responsible for these reactions are localized in the lipid substances which are not essential for eliciting immunity to tuberculosis.The lipid contents of 3 mycobacterial strains (BCG-Prague, BCG-Copenhagen, and MP-Prague-the latter an attenuated strain of Myco. microti) were repeatedly analysed during the period 1964-66. The latter 2 strains-of high and low lipid content respectively-were injected intradermally into 2 tuberculin-positive human volunteers and their cytopathic effects studied. The local reaction to MP-Prague was minimal and healed completely after 1 month; severe ulcerous reactions requiring 4 months to heal were observed with BCG-Copenhagen.Electron-microscopic investigation of ultrathin sections showed marked differences in the surface structure of these strains, indicating that they had different ways of disintegrating in vivo.The authors suggest that mycobacterial strains with a low lipid content and established immunogenicity may be more valuable for tuberculosis prophylaxis than BCG or other attenuated mycobacteria.

Comparison of photometric and weight estimation of Mycobacterium content in homogenous BCG cultures containing Tween 80

A comparison of the weight and photometric methods of primary assay of BCG vaccine has been made, using a vaccine prepared in albumin-free medium but containing Tween 80. In the weight method, the bacteria were trapped on a membrane filter; for photometry a Pulfrich Elpho photometer and an instrument of Czech origin were used. The photometric results were the more precise, provided that the measurements were made within two days of completion of growth; after this time the optical density of the suspension began to decrease slowly. The lack of precision of the weighing method is probably due to the small weight of culture deposit (which was almost on the limit of accuracy of the analytical balance) and to difficulties in the manipulation of the ultrafilter.