cAMP concentration,morphological differentiation and citric acid production in Aspergillus niger

Summary The possibility that adenosine 3,5 monophosphate exerts an effect on citric acid production by Aspergillus niger by influencing pellet morphology has been investigated. The effect of pH and inoculum size on pellet formation, citric acid production, and intracellular and extracellular cAMP levels were studied. High levels of intracellular and extracellular cAMP in the later stages of the fermentation, the period of maximum citric acid formation, were associated with those treatments which gave pellets of intermediate size. The highest cAMP levels were associated with those treatments which gave the highest citric acid titre. It was concluded that high cAMP levels are principally associated with an optimum physiological state for citric acid production and that cAMP levels do not vary directly with pellet size.     

Detection of suspicious cells and rejection of artefacts in cervical cytology using the Leyden Television Analysis System.

In slide based automation of cervical cytology the first stage of analysis involves finding possibly suspicious cells, or areas on the slide with these types of cells. By using a television based system such as the Leyden Television Analysis System (LEYTAS), a number of detection methods can be applied to rapidly screen a large number of fields automatically for suspicious cells. In this paper, results using a parameter based on increased nuclear DNA content of cells are given and a second detection method based on a chromatin pattern feature, called chromatin contrast, is discussed. Two blind trials on 41 positive and 22 negative cervical slides, using the Leyden Television Analysis System to detect suspicious cells with an increased nuclear DNA content, were promising. In 1 of the 41 positive cases no suspicious cells were found. In the negative specimens, suspicious cells were detected in 1 of 9 cases and 1 of 13 cases, with the two detection parameters investigated. These findings are discussed and some automatic artefact rejection procedures with preliminary results are given.     

Inability of IL-2 and IL-10 to counteract B cell clonal deletion.

The B cell antigen receptor (BCR) delivers inhibitory signals in nascent B cells leading to the establishment of tolerance via clonal deletion or clonal anergy depending upon the type of antigen to which the B cells are exposed. In previous work, it has been demonstrated that activated Th2 cells, as well as some recombinant lymphokines, prevent the inhibition of growth and subsequent cell death induced through the BCR in model B cell lymphomas. Herein, we extend this work to another Th2 lymphokine, IL-10, that in contrast to IL-4 does not interfere with the deletion promoted by IgM crosslinking. The effect of individual lymphokines has also begun to be analyzed in a transgenic model of B cell clonal deletion. To this end, we have administered a recombinant vaccinia virus producing human IL-2 to mice expressing an autoreactive H-2Kk,b-specific transgenic IgMk and found that IL-2 does not abrogate B cell deletion in vivo.     

The effect of exhaustive exercise on expired pentane as a measure of in vivo lipid peroxidation in the rat

The concentrations of pentane and ethane in the expired breath of swimming rats were used to determine the possible occurrence of lipid peroxidation caused by strenuous exercise. Rats swum to exhaustion produced significantly more pentane but not ethane than did rats at rest. Rats fed a vitamin E-deficient diet produced slightly more pentane following exhaustive exercise than they did while at rest, but this increase was not statistically significant. Rats were also swum for prescribed lengths of time. Only rats that had swum for 20 or 40 min had significantly elevated concentrations of pentane in the breath. Rats swum for 10 or 30 min had elevated concentrations of pentane in the breath, but these increases were not statistically significant. These results suggest that lipid peroxidation is moderately increased following exhaustive exercise.     

Evolution of chromosomal abnormalities in sequential cytogenetic studies of ataxia telangiectasia

Summary Sequential cytogenetic studies of four patients with ataxia telangiectasia showed the progressive development of lymphocyte clones, each marked with a rearranged chromosome 14. Initial studies had shown random chromosomal breaks and rearrangements. Later studies in all patients showed nonrandom rearrangement of chromosome 14 with a breakpoint at 14q12 and with the distal segment translocated to either chromosome 14 or 7. The proportion of circulating lymphocytes carrying the marker tended to increase with time, accounting for the majority of the lymphocytes eventually in one case. The marked lymphocyte clones evolved further, as a result of loss of the small centric portions of the rearranged chromosome 14 (14pter14q12).Perhaps the abnormal clones in ataxia telangiectasia escape immunologic surveillance and flourish in an immunologically impaired environment. Subsequent to the loss of the centric portion of the rearranged chromosome 14, the cells may acquire additional capabilities that enhance malignant transformation.     

Evaluation of Nosema locustae (Microsporida) as a control agent of grasshopper populations in Saskatchewan

A quantitative study of the effect of a microsporidan, Nosema locustae, as a control agent against grasshopper populations in Saskatchewan, Canada, revealed that 50% of the populations of Melanoplus sanguinipes, M. packardii, and Camnula pellucida were infected between 4 and 5 weeks (400 to 424 degree-days) after application of the pathogen. Maxima of 95–100% infection were evident between 9 and 12 weeks (600–700 degree-days) after application. The percentage reduction in surviving populations of M. sanguinipes, i.e., those that did not die from natural causes, reached about 20% by the 4th week (400 degree-days) after inoculation, about 50% by the 9th week (600 + degree-days), and a maximum of about 60% by the 12th week (700 degree-days). An exponential relationship was obtained between percentage reduction and percentage infection in all three species. However, a similar percentage infection resulted in different percentage reduction in the populations. Results also revealed that the rate of reduction in populations reached its peak by about 40–80 degree-days before the maximum rate of infection was attained for each species. Egg production in the two Melanoplus species in treated plots was significantly lower (P < 0.05) than in the control plot.     

Effect of Polychlorinated Biphenyl Formulations on the Growth of Estuarine Bacteria

Polychlorinated biphenyl formulations inhibited the growth of certain estuarine bacteria. The sensitive strains, although exhibiting some similar physiological characteristics, contained both gram-positive and gram-negative bacteria.     

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Vaginal microbiome-hormonal contraceptive interactions associate with the mucosal proteome and HIV acquisition

Alterations to the mucosal environment of the female genital tract, such as genital inflammation, have been associated with increased HIV acquisition in women. As the microbiome and hormonal contraceptives can affect vaginal mucosal immunity, we hypothesized these components may interact in the context of HIV susceptibility. Using previously published microbiome data from 685 women in the CAPRISA-004 trial, we compared relative risk of HIV acquisition in this cohort who were using injectable depot medroxyprogesterone acetate (DMPA), norethisterone enanthate (NET-EN), and combined oral contraceptives (COC). In women who were Lactobacillus-dominant, HIV acquisition was 3-fold higher in women using DMPA relative to women using NET-EN or COC (OR: 3.27; 95% CI: 1.24–11.24, P = 0.0305). This was not observed in non-Lactobacillus-dominant women (OR: 0.95, 95% CI: 0.44–2.15, P = 0.895) (interaction P = 0.0686). Higher serum MPA levels associated with increased molecular pathways of inflammation in the vaginal mucosal fluid of Lactobacillus-dominant women, but no differences were seen in non-Lactobacillus dominant women. This study provides data suggesting an interaction between the microbiome, hormonal contraceptives, and HIV susceptibility.