Studies on the immunoglobulin spectrum of porcine serum and colostrum

An analysis of the immunoglobulin region of porcine blood serum proved the presence of a number of protein fractions which is higher than in other animal species. The presence of antibody activity to tetanus anatoxin examined by radioimmunoelectrophoresis was found in three γ G-globulin fractions, which could be distinguished from each other, and also in two additional fractions. One of the latter was the γ-macroglobulin fraction and the other one might correspond to γ A-globulin even though its mobility was higher than the mobility of γ A-globulin of human serum. A comparison of the immunoglobulin spectrum of porcine serum, colostrum, and of the suckling pig serum after ingestion of the colostrum showed that the main component of porcine colostrum constitutes the γ G-immunoglobulin, even though the colostrum seems to contain other components of the latter which have a higher electrophoretic mobility. The antibody activity of colostrum was found only in fractions γ G and γ M. The fraction of colostrum which might correspond to γ A did not display any activity at all. The activity in suckling pig serum was also concentrated in fractions γ G and γ M.     

Seric and secretory antibodies reactive to α, β and γ intimins of Escherichia coli in healthy Brazilian adults

Intimin is essential for attaching and effacing lesions by pathogens such as enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC), and the antigenic polymorphism of intimin determines distinct subtypes. Our aim was to investigate the presence of immunoglobulin G (IgG) and IgA antibodies reactive to α, β and γ intimins in serum and colostrum from healthy Brazilian adults. We found seric IgG and secretory IgA antibodies reactive to conserved and variable regions of α, β and γ intimins and a positive correlation between the concentrations of these antibodies in both serum and colostrum that suggested cross reactivity among anti-intimin antibodies, as was confirmed by immunoblotting and absorption. The concentrations of anti-conserved region antibodies were higher than those of variable region antibodies. The presence of antibodies reactive to EHEC antigens could result from contact with EPEC or with other bacteria of the environment even though this bacterium is not frequent in Brazil, and suggests possible protection against EHEC.     

Effects of pulsed electric fields on DNA of human lymphocytes

The effects of pulsed electric fields of low frequency (50 Hz) on DNA of human lymphocytes were investigated. The influence of additional external factors, such as hydrogen peroxide (H₂O₂) and γ-irradiation, as well as the repair efficiency in these lymphocytes, was also evaluated. The comet assay, a very sensitive and rapid method for detecting DNA damage at the single cells level was the method used. A significant amount of damage was observed after exposure to the electric fields, compared to the controls. After 2 h incubation at 37^°C, a proportion of damage was repaired. H₂O₂ and γ-irradiation increased the damage to lymphocytes exposed to pulsed electric fields according to the dose used, while the amount of the repair was proportional to the damage.     

Role of gamma irradiation in regulation of NO3 level in rocket (Eruca vesicaria subsp. sativa) plants

The changes in the growth indices and certain metabolic activities in response to different doses of γ-irradiation (0, 20, 50, 100, and 200 Gy) were studied, using rocket seedlings. The total yield, seed mass, and essential oil content increased significantly by 20 Gy dose of γ-irradiation as compared with the control samples. In addition, total sugars, total free amino acids, total soluble phenols, kinetin, GA₃, nitrate reductase activity, and total protein increased significantly at 20 Gy dose. Meanwhile, NO₃ content decreased significantly at 20 Gy dose. The nitrogen and potassium content increased at the same dose of gamma rays of 20 Gy. While the phosphorus content showed no significant effect at all the γ-irradiation doses used. The results obtained in this work revealed that the most effective dose was 20 Gy of gamma rays. It was suggested that pretreatment of rocket seeds before planting with 20 Gy dose of γ-irradiation, may oppose the harsh effect of NO₃ accumulation and increased the quality and quantity of rocket yield. Published in Russian in Fiziologiya Rastenii, 2006, Vol. 53, No. 2, pp. 215–219. The text was submitted by the author in English.     

Pre-sowing gamma irradiation of cotton seeds from a point source of Cs137 and its effect on emergence,growth and yield

Summary The effect of pre-sowing -irradiation of cotton seeds from a point source of Cs¹³⁷ on emergence, growth, flowering, and yield was studied. High radiation doses caused reduction of emergence, inhibition of growth retardation of flowering, and reduction in number of flowers and bolls produced by the plant. The yield was greatly reduced under high dosages and approached that of the control plants under low dosages. -rays caused a marked degree of sterility.No significant stimulating effect on growth and development was detected when the dry cotton seeds were subjected to -irradiation doses of 1.17 to 26.92 kr.     

Gamma irradiation induced apoptotic changes in the chromatin structure of human erythroleukemia K562 cells

Exponentially growing human erythroleukemia K562 cells were synchronized by centrifugal elutriation prior to and after Co⁶⁰ γ-irradiation (4 Gy). Forward scatter flow cytometry used for size analysis revealed the increase of an early apoptotic cell population ranging from lower (0.05 C-value) to higher DNA content (∼1 C) as the cells progressed through the S phase. The increase in cellular DNA content expressed in C-values correlated with apoptotic chromatin changes manifested as many small apoptotic bodies in early S phase and larger but less numerous disintegrated apoptotic bodies in late S phase. Most significant changes after exposure to γ-irradiation took place in early S phase resulting in an increase of nuclear size by more than 50%. Cell fractions containing irradiated cells showed enhanced growth arrest at 2.4 C-value, which was accompanied by apoptosis. Apoptotic cell cycle arrest near to the G₁/G₀ checkpoint and apoptotic changes indicate that the radiation resistance of K562 cells is related to the bypass of the early stage of the p53 apoptotic pathway. Apoptotic changes in chromatin structure induced by γ-irradiation indicate that these injury-specific changes can be identified and distinguished from chromatin changes induced by UV radiation or heavy metals.     

Promyelocytic leukemia protein interacts with werner syndrome helicase and regulates double-strand break repair in γ-irradiation-induced DNA damage responses

We show here that γ-irradiation leads to the translocation of endogenous Werner syndrome helicase (WRN) from nucleoli to nucleoplasmic DNA double strand breaks (DSBs), and WRN plays a role in damage repair. The relocation of WRN after irradiation was perturbed by promyelocytic leukemia protein (PML) knockdown and enhanced by PML IV over-expression. PML IV physically interacted with WRN after irradiation. Amino acids (a.a.) 394 to 433 of PML were necessary for this interaction and the nucleoplasmic translocation of WRN and were involved in DSB repair and cellular sensitivity to γ-irradiation. Taken together, our results provide molecular support for a model in which PML IV physically interacts with and regulates the translocation of WRN for DNA damage repair through its 394–433 a.a. domain.     

Gamma-irradiation depletes endogenous germ cells and increases donor cell distribution in chimeric chickens

The production of chimeric birds is an important tool for the investigation of vertebrate development, the conservation of endangered birds, and the development of various biotechnological applications. This study examined whether gamma (γ)-irradiation depletes endogenous primordial germ cells and enhances the efficiency of somatic chimerism in chickens. An optimal irradiation protocol for stage X embryos was determined after irradiation at various doses (0, 100, 300, 500, 600, 700, and 2,000 rad). Exposure to 500 rad of γ-irradiation for 73 s significantly decreased the number of primordial germ cells (P < 0.0001). Somatic chimera hatchlings were then produced by transferring blastodermal cells from a Korean Oge into either an irradiated (at 500 rad) or intact stage X White Leghorn embryo. An analysis of feather color pattern and polymerase chain reaction-based species-specific amplification of various tissues of the hatchlings confirmed chimerism in most organs of the chick produced from the irradiated recipient; a lesser degree of chimerism was observed in the non-irradiated control recipient. In conclusion, the exposure of chick embryos to an optimized dose of γ-irradiation effectively depleted germ cells and yielded greater somatic chimerism than non-irradiated control embryos. This technique can be applied to interspecies reproduction or the production of transgenic birds.     

Role of Disulphide Bonds in the Resistance of Bacillus cereus Spores to Gamma Irradiation and Heat

S ummary . Spores of Bacillus cereus were treated with thioglycollic acid which ruptures at least 10–30% of the spore disulphide bonds by reducing them to thiol groups. The treated spores were still viable and were sensitive to lysozyme but remained as resistant to γ-irradiation and to heat as untreated spores. Neither treated nor untreated spores were sensitized to irradiation by reagents which block thiol groups. The results did not indicate that the high content of disulphide bonds in spore coat protein protects spores against inactivation by irradiation or heat.     

Characterisation of the Schizosaccharomyces pombe rad4/cut5 mutant phenotypes: dissection of DNA replication and G2 checkpoint control function

Mutation of the essential Schizosaccharomyces pombe rad4/cut5 gene causes sensitivity to UV and ionising radiation at the permissive temperature whilst at the restrictive temperature cells fail to undergo DNA replication but still attempt mitosis owing to a defective S-phase checkpoint response. Many mutations in genes encoding DNA replication proteins also abolish checkpoint responses, possibly because the replication machinery is a pre-requisite for the generation of the signal. We demonstrate here that rad4/cut5 cells fail to arrest cell division when treated with the replication inhibitor hydroxyurea at the semi-permissive temperature 32° C, but retain essentially normal replicative capacity. This demonstrates that the replication and checkpoint function of the rad4/cut5 gene product can be separated and that the Rad4 protein differs from other replication proteins in being directly involved in generating the S-phase checkpoint signal. Furthermore, we have investigated the checkpoint response or rad4/cut5-deficient cells to γ-irradiation and UV-mimetic drugs. We find that, at the restrictive temperature, the rad4 ⁻ /cut5 ⁻ cells fail to delay mitosis in response to γ-irradiation whilst retaining a normal checkpoint response to the UV-mimetic drug 4-nitroquinoline-1-oxide. The lack of the γ-irradiation checkpoint is reminiscent of the deficiency associated with mutation of the human ATM locus, the causative deficiency of the heritable disorder ataxia telangiectasia. The implications of our results for the organisation of distinct checkpoint-response pathways in both fission yeast and mammalian cells are discussed. Moreover the data are consistent with a model in which the generation of the S-Phase checkpoint signal is DNA polymerase ɛ dependent. Received: 29 October 1996 / Accepted: 14 January 1997     

Endoreduplication in Drosophila melanogaster progeny after exposure to acute γ-irradiation

Radiation and Environmental Biophysics - The purpose of this investigation was to study the effect of acute γ-irradiation of parent adults on the endoreduplication of giant chromosomes in F1...     

Evaluation of hprt mutant assay as a biomarker monitoring the specific environmental mutagen

To evaluate the availability of an hprtmutant assay for monitoring a specific environmental mutagen, the mutation effects of -irradiation and pentachlorophenol (PCP) on the hypoxanthine guanine phosphoriboxyl transferase (hprt) locus in a human T-cell culture system were analyzed in vitro. The assay of somatic mutation at the hprtlocus did not differentiate the characteristic effect of -irradiation from that produced by PCP, because both damaging agents induced the somatic mutations in a similar dose-dependent manner. Direct DNA sequencing showed that both damaging agents induced different mutation spectra in the hprtlocus of T-cells. The large deletions, which account for 75% of the analyzed mutants, were induced by -irradiation. By contrast, point mutations such as base substitutions rose up to 97% in the case of PCP-treated cells. It may be that 190 base pair and 444 base pair positions are hot spots induced by PCP. These results suggest that the hprtmutation spectrum can be used as a potential biomarker for assessing a specific environmental risk.     

Strain improvement inStreptomyces galilaeus,a producer of anthracycline antibiotics galirubins

The production of ε-pyrromycinone glycosides inStreptomyces galilaeus increased 12-fold, with respect to the wild strain, as a result of a sequential procedure including both natural selection and treatment with mutagens (nitrous acid, UV light and γ-irradiation). Nitrous acid exhibited the highest mutagenic effect, both in increasing the productivity and in inducing blocked mutants. A mutant strain blocked in the biosynthesis of glycosides and accumulating free ε-pyrromycinone as the principal metabolite was obtained.     

Gamma-radiation upregulates MHC class I/II and ICAM-I molecules in multiple myeloma cell lines and primary tumors

Summary The γ-irradiation of normal cells causes an increased synthesis of specific proteins. However, few studies have described the effects of high doses of irradiation on the expression of cell surface antigens in tumor cells. This study analyzed the effects of high doses of γ-irradiation on the surface antigen expression of Major Histocompatability Complex (MHC) class I/II and intercellular adhesion molecule-1 (ICAM-I) in human multiple myeloma (MM) cell lines ARP-1, ARK-RS, and 10 MM primary tumors. The expression of surface antigens was evaluated by fluorescence-activated cell sorter analysis at different time points, following the exposure to high doses of γ-irradiation. Doses of 10,000 and 15,000 cGy were no0105 sufficient to totally block cell replication in both cell lines and primary tumors; cell replication was able to be inhibited completely only at 18,000 cGy. Lower doses (10,000 cGy) and lethal doses of irradiation (i.e., 15,000 and 18,000 cGy) increased the expression of all surface antigens present on the cells before irradiation. Essentially, such upregulation was shown to be dose dependent, with higher radiation doses resulting in higher antigen expression. Furthermore, when the kinetics of this upregulation were studied 3 and 6 d after irradiation, there was a constant increase in antigen expression in MM cells. These findings suggest that upregulation of costimulatory molecules, such as of MHC class I/II antigens and ICAM-1 molecules in MM patients treated by γ-radiation, can increase the immunogenicity of the tumor cells. In light of these findings, radiotherapy combined with immunotherapy might be considered in relapsing patients after receiving the standard treatment.     

Identification of soil micro-habitats for growth, death and survival of a bacterium, γ-1,2,3,4,5,6-hexachlorocyclohexane-assimilating Sphingomonas paucimobilis, by fractionation of soil

Abstract A soil bacterium, Sphingomonas paucimobilis , is known to be the only bacterium which can aerobically assimilate γ-1,2,3,4,5,6-hexachlorocyclohexane (γ-HCH). Indigenous γ-HCH-assimilating S. paucimobilis survives in the soil where γ-HCH has been annually applied since 1973. In contrast, γ-HCH-assimilating S. paucimobilis strain SS86 cannot survive when inoculated into the control soil, although it can multiply in the presence of γ-HCH. Micro-habitats of γ-HCH-assimilating S. paucimobilis indigenous or inoculated into the soils were identified by fractionation of the soils. When γ-HCH was added to the soil, indigenous γ-HCH-assimilating S. paucimobilis grew. Most of the growing indigenous bacteria were found in fractions smaller than 0.025 mm which corresponded to soil inter-aggregate pores, and died afterwards. However, the indegenous bacteria which survived for a long period were found mainly in fractions larger than 0.025 mm which contained soil aggregates. When γ-HCH-assimilating strain SS86 was inoculated, the bacteria were located in inter-aggregate pores and died quickly. Consequently, association of the bacteria with soil aggregates was suggested to be related to the long-term survival of γ-HCH-assimilating S. paucimobilis .     

A dual approach in the study of poly (ADP-ribose) polymerase: In vitro random mutagenesis and generation of deficient mice

A dual approach to the study of poly (ADP-ribose)polymerase (PARP) in terms of its structure and function has been developed in our laboratory. Random mutagenesis of the DNA binding domain and catalytic domain of the human PARP, has allowed us to identify residues that are crucial for its enzymatic activity.In parallel PARP knock-out mice were generated by inactivation of both alleles by gene targeting. We showed that: (i) they are exquisitely sensitive to -irradiation, (ii) they died rapidly from acute radiation toxicity to the small intestine, (iii) they displayed a high genomic instability to -irradiation and MNU injection and, (iv) bone marrow cells rapidly underwent apoptosis following MNU treatment, demonstrating that PARP is a survival factor playing an essential and positive role during DNA damage recovery and survival.     

Response to DNA-damaging agents in cultured cells from patients with X-linked duchenne muscular dystrophy phenotype: male DMD,female DMD,possible carriers

Using blood cultures the response to gamma () radiation was examined in a male DMD and his mother, in a female DMD and her mother and in a normal control. In a series of experiments chromosome aberrations were determined after 3 separate -irradiation dose levels: 0, 150, 300 rads. The DMD patients showed a response to ionising radiations different from control, in fact the percentage of aberrations was lower than the control. In this preliminary study a slight difference between normal and possible carriers was also found.     

Lipid peroxidation in microsomes of murine bone marrow after low-doseγ-irradiation

The principal aim of the study was to investigate the effect of low-dose-irradiation on lipid peroxidation (LPO) in murine bone marrow. To this end, the degree of LPO in suspensions of microsomes of murine bone marrow cells (BMC) was determined in terms of malondialdehyde (MDA) formation after whole-body or in vitro exposure to various doses of-radiation. These effects were compared to some extent with similar effects in liver and spleen preparations. As to the effect of-irradiation on LPO in BMC, the response depends on the dose level and on whether whole-body or in vitro exposures are involved. Whole-body irradiation did not result in an increase in LPO in BMC microsomes, even at such high doses as 15 Gy, although hepatic microsomes showed a marked increase. In contrast, in vitro irradiation of BMC microsomes with 0.1, 10 and 50 Gy brought about an increase in LPO. This increase was already significant (P <0.05) at 0.1 Gy following a post-irradiation incubation and substantial at 50 Gy, even without subsequent incubation. The results show that low doses of-irradiation are able to induce an elevation of LPO in murine BMC microsomes, but only after in vitro irradiation. In the case of whole-body irradiation cellular radical scavengers and other metabolic reactions may prevent a measurable increase in LPO. This is partly illustrated by the case of vitamin-E deficiency, where a substantial increase in LPO in BMC microsomes is observed even without-irradiation in comparison with euvitaminotic mice because normally occurring radicals are not scavenged sufficiently.On leave from the University of Rochester, School of Medicine and Dentistry, Rochester, NY 14678, USA     

Modification of Repair DNA Synthesis in Mutagen-Treated Human Fibroblasts during Adaptive Response and the Antimutagenic Effect of Garlic Extract

Repair DNA synthesis (RDS) in human fibroblasts during the adaptive responses (ARs) induced by cadmium chloride (CdCl₂), -radiation, and 4-nitroquinoline-1-oxide (4NQO) was compared in cells pretreated and not pretreated with garlic extract. The RDS was increased during the ARs induced CdCl₂ and -irradiation. Garlic extract stimulated RDS in cells treated by the same mutagens. 3-Aminobenzamide (3AB), an inhibitor of poly(ADP-ribose) polymerase, decreased the RDS rate in cells treated with CdCl₂ and -irradiation but had no significant effect on cells treated with 4NQO. It was demonstrated that DNA repair was involved into cell protection in different ways in the cases of antimutagen treatment and AR.     

Effects of γ-irradiation on antioxidant activity in soybean seeds

There are some reports that low doses of γ-irradiation could induce antioxidant activities in plant material, including soybean. Irradiation, required for the inactivation of some pathogens and induction of mutations, may have adverse effects on sensorial, nutritional and antioxidant qualities. The effects of different γ-irradiation doses (100–200 Gy) on antioxidant properties of soybean seeds was investigated. In this study, we report the results obtained by analysis of antioxidant enzyme activities, reduced glutathione, malonyldialdehyde (MDA) and hydroxyl (HO⁻) radical quantities, soluble protein content, and total antioxidant activity in irradiated soybean seeds. Antioxidant enzyme activities were affected due to high irradiation intensity. Significant changes of total antioxidant activity and MDA and HO.quantities were observed only under the highest irradiation dose, with a 15.7% reduction in total antioxidant activity, MDA quantity increase of 21.6%, and HO⁻ radical quantity increase of 79.3% compared to the non-irradiated control. The total soluble protein content increased slightly.