Possible implications of reciprocity between ethylene and aflatoxin biogenesis in Aspergillus flavus and Aspergillus parasiticus.

Aspergillus flavus and Aspergillus parasiticus produced ethylene during early growth. However, the onset of toxin biosynthesis was marked by the absence of ethylene evolution. 2-Chloroethyl phosphonic acid, an ethylene-generating compound, inhibited aflatoxin biosynthesis in vivo. The reciprocal relationship between the production of aflatoxin and ethylene by the organism may indicate the involvement of the latter in the regulation of aflatoxin biogenesis.     

In vivo recombinant interleukin 2 administration enhances survival against a lethal challenge with Toxoplasma gondii

Administration of recombinant interleukin 2 (rIL 2) resulted in a significant (p less than 0.01) decrease in mortality in mice infected with a dose of Toxoplasma gondii that killed 100% of untreated mice. Mice treated with rIL 2 had a significantly (less than 0.005) lower numbers of cysts in the brains. The protection afforded by rIL 2 could not be correlated with increased antibody synthesis or be explained by increased macrophage killing in the treated mice. Mice treated with rIL 2 after Toxoplasma infection demonstrated increased natural killer (NK) cell activity compared with either Toxoplasma-infected or rIL 2-treated mice. rIL 2 failed to reverse the suppressed proliferative response of lymphocytes to concanavalin A and lipopolysaccharide in mice acutely infected with a virulent strain of T. gondii. These results reveal that rIL 2 may have a remarkably protective effect against intracellular parasites.     

A mechanism for rich-medium inhibition of the repair of daughter-strand gaps in the deoxyribonucleic acid of UV-irradiated Escherichia coli K12 uvrA

Ultraviolet-irradiated Escherichia coli K12 uvrA(B,C) cells show higher survival if plated on minimal growth medium (MM) rather than on rich growth medium (RM). This phenomenon has been referred to as 'minimal medium recovery' (MMR). UV-irradiated (4 J/m2) uvrA cells showed a similar rate of protein synthesis, whether incubated in MM or RM, however, they showed a severe depression in DNA synthesis when incubated in MM that lasted for about 30 min, and the normal rate of DNA synthesis was not reestablished until about 60 min after irradiation. When a sample of these same cells was switched to RM immediately after UV-irradiation, there was only a slight slowing of DNA synthesis, and the normal rate of synthesis was reestablished by 60 min. An additional mmrA mutation or growth retardation by valine blocked both this extra DNA synthesis in RM, and the inhibitory effect of RM on survival. These findings suggest that the absence of a marked delay in DNA synthesis observed in RM may be responsible for the inhibitory effect of RM on the survival of UV-irradiated excision-deficient cells. Two hypotheses, which are not mutually exclusive, are proposed and supported by data to explain why a fast rate of DNA synthesis after UV-irradiation partially inhibits postreplication repair and enhances cell lethality.     

Lipids of Cuscuta reflexa and changes in lipids of its host plants after infection

The lipid level (fresh weight basis) of Cuscuta reflexa Roxb. was related to the lipid content of the host plants Meilicago saliva L., Helianthus annuus L., Pisum sativum L. and Lantana camara L. Parasitizing by the dodder significantly increased the total lipid level of the hosts. The increase was mainly due to enhancement in the neutral lipid fraction.
The level of phospholipid in the parasite was always higher than in its hosts. Phospholidyl choline and phosphatidyl ethanolamine constituted about 65% of the total phospholipid of Cuscuta. This was followed by phosphatidyl inositol (ca 20%) and phosphatidyl glycerol (ca 12%). Phosphatidic acid constituted only ca 3% of the phospholipids of Cuscuta. Although the total phospholipid levels of various host plants were not affected as a result of the infection by Cuscuta, a significant decrease occurred in the levels of phosphatidyl eholine and phosphatidyl ethanolamine as well as marked increases in phosphatidyl inositol and phosphatidic acid. The infected tissue showed an increase in phospholipase D activity as compared with the controls. The results have been discussed in relation to changes in permeability of the infected tissue.     

Geminate recombination of CO in rabbit, opossum, and adult hemoglobins

The geminate recombination of CO with Hb following dissociation by a 10-ns laser pulse has been studied as a function of pH (9.2 and 7.0 without inositol hexaphosphate and 6.0 with inositol hexaphosphate) and temperature (5-35 degrees C). The hemoglobins studied included adult, Rothschild, rabbit, opossum, and carp. Despite significant differences in their structural and functional properties, the first four of these hemoglobins show similar trends in the yields, rates, and activation energies of the geminate recombination. The nature of the "cage recombination" in hemoglobin is discussed in the light of such findings. Neither a slow diffusion model nor a model based upon a specific non-heme binding site accounts for the observations.     

A possible adenine nucleotide storage form in normal and ischaemic rat heart

Perfusion of Langendorff rat hearts with [¹⁴C]adenosine yields an acid-insoluble, radioactive product whose concentration falls during ischaemia. The properties of the substance show that it is a polyribonucleotide. It is suggested that it may be mitochondrial poly A acting as a storage form of adenine nucleotides.     

Dystocia due to urinary bladder carcinoma in two water buffaloes (bubalus bubalis) - Clinical case report

Two buffaloes with full-term pregnancy suffered from dystocia because the cervix did not dilate in spite of strong labour pains and other parturition signs shown by each animal. The urinary bladder, cervix, vagina and surrounding area were very firm. Dead, emphysemated fetuses were removed by caesarean in each case and anuria was also noticed. One buffalo died and the other was euthanised after surgery because it did not improve. The post-mortem examinations revealed transitional cell carcinoma of urinary bladder infiltrating the cervix, vagina and surrounding area in each case.