The influence of water and electrolyte replacement therapy and treatment with antibiotics against acute (3 to 5 day) intestinal radiation deaths in rats exposed to an acute lethal dose of x radiation was studied. The administration of sterile 0.9% solution containing either NaCl or a mixture of NaCl, Na lactate, and KCl during the critical 2 to 5 day period after irradiation had little, if any, protective effect. However, treatment with antibiotics during the same period definitely increased the number of survivors. This antibiotic -effect was enhanced significantly when NaCl, but not when equiosmolar glucose, was a constituent of the infusion solution given concurrently with the drug. The results strongly suggest that microorganisms may play a more prominent role than dehydration in the genesis of acute intestinal radiation death in the rat, but that dehydration must also be taken into account in the treatment of acute intestinal radiation injury. A comparison between whole-body and abdomen-only irradiated animals given a dose of 910 r showed that the therapeutic measures used were about equally effective against acute intestinal radiation death in the former as in the latter cases. It was observed, however, that third-day deaths, which were so prominent in whole-body irradiatedmore » animals, were virtually absent in cephalic one-half-shielded, abdomen-irradiated animals. it was further observed that these therapeutic measures were ineffective against deaths occurring primarily as a consequence of radiation-induced injury to the hematopoietic system, as evidenced by the high incidence of deaths during the second postexposure weeks (the period usually associated with bone marrow radiation syndrome) in whole-body but not in partial-body irradiated animals. A large number of 5 day survivors, protected against acute intestinal radiation death by the combined saline and antibiotic therapy after 1000 r of x irradiation to the abdomen only, died during the subsequent week. These deaths, which occurred in bone marrowshielded animals, apparently resulted from radiation injury sustained by the small intestine and not by any other abdominal viscera in the radiation field. (auth)« less
Breadboard simulations of life sciences laboratory concepts for conducting bioresearch in space were undertaken as part of the concept verification testing program. Breadboard simulations were conducted to test concepts of and scope problems associated with bioresearch support equipment and facility requirements and their operational integration for conducting manned research in earth orbital missions. It emphasized requirements, functions, and procedures for candidate research on crew members (simulated) and subhuman primates and on typical radioisotope studies in rats, a rooster, and plants.
Addition of the long arm of barley chromosome 1H (1HL) to wheat causes severe meiotic abnormalities and complete sterility of the plants. To map the barley gene responsible for the 1H-induced sterility of wheat, a series of addition lines of translocated 1H chromosomes were developed from the crosses between the wheat 'Shinchunaga' and five reciprocal translocation lines derived from the barley line St.13559. Examination of the seed fertility of the addition lines revealed that the sterility gene is located in the interstitial 25% region of the 1HL arm. The genetic location of the sterility gene was also estimated by physically mapping sequence-tagged site (STS) markers and simple-sequence repeat (SSR) markers with known map locations. The sterility gene is designated Shw (sterility in hybrids with wheat). Comparison of the present physical map of 1HL with two previously published genetic maps revealed a paucity of markers in the proximal 30% region and non-random distribution of SSR markers. Two inconsistencies in marker order were found between the present physical map and the consensus genetic map of group 1 chromosomes of Triticeae. On the basis of the effects on meiosis and chromosomal location, the relationship of the present sterility gene with other fertility-related genes of Triticeae is discussed.Key words: Hordeum vulgare, molecular markers, sterility, translocation, wheatbarley chromosome addition line.
Preharvest sprouting is a serious problem in grain crop production because it causes quality deterioration and economic losses. It is well known that grain colour is closely associated with grain dormancy in wheat; white-grained lines without accumulating proanthocyanidins in testa tend to be more susceptible to preharvest sprouting than red ones. All available white-grained wheat lines are restricted to triple recessive mutations at the R loci (R-A1, R-B1, and R-D1), but barley is known to have 11 independent loci conferring the proanthocyanidin-free grain phenotype. In this study, we evaluated the dormancy levels of anthocyanin/proanthocyanidin-free ant17 mutants. Three ant17 mutants showed the same levels of dormancy as their respective wild types. Sequencing of three independent ant17 alleles detected a point mutation within the coding regions of flavanone-3-hydroxylase (F3H), which are predicted to cause a premature stop codon at different sites. The F3H locus completely cosegregated with the Ant17 position on the chromosome arm 2HL. Expression of the barley F3H gene was observed in pigmented tissues, but not in nonpigmented roots and stems. This result indicates that wheat F3H may be a promising new target locus for breeding white-grained lines with a practical level of preharvest sprouting resistance.
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