SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
In our electron microscopy, acidiphils in the pituitary autografts placed in the renal capsules of immature male rats underwent a sequential transformation with the lapse of time: Within 3 and 6 days, all the somaotrophs packed with the large granules of about 350 mmu diameter dispersed. The size and number of the granules in somatotrophs were quickly and markedly reduced with severe modification of cell shape. There was evidence during this time course that Siperstein's or Moriarty's corticotrophs might be synonymous with the stellate shape of acidophils with the arrangement of small granules 150-200 mmu in diameter along the cell acidophils. The "acidophils of the small granule type" possibly related to ACTH production according to Yoshimura et al. (1974) were frequently detected in the grafts as elongated or irregularly shaped cells. Their minute granules 100-150 mmu in diameter were also distributed in row in the cytoplasmic peripheral area. Gradual loss of the minute granules below 100 mmu in diameter eventually made the acidophils to transform into agranular cells. Our own idea that ACTH secretion might correlate with a series of cells transforming along the acidophil-axis was indirectly supported by the present observation on pituitary grafts. On the other hand, basophils rapidly degenerated and died away. Ten and 20 days after autografting, the graft cells which might be principally composed of the cells of acidophil origin enormously proliferated through mitotic division, showing the homologous fine structure, without the normal cell individuality. They always contained three different size and shape of granules simulataneously. Significance of such a rapid and strong response of acidophils to the ectopic replacement in the immature male rats was discussed from the view-point of hypothalamic regulation to simple protein hormones.
The influence of pH on the specific growth rates of two acidophilic and two neutrophilic soil streptomycetes was studied. The acidophiles had maximum growth rates over a broad range from pH 4.5 to 5.5, while the neutrophiles had clearly defined optima at pH 7.0. Mycelium of neutrophiles was less tolerant of acidity than that of acidophiles; both showed decreased viability at pH levels below those which allowed growth. Spores of neutrophiles and acidophiles were equally tolerant of acidity and this may allow the former to survive in acid soils. Both spores and mycelium of acidophiles remained viable at pH levels above those allowing growth.
The effect of pH on the starch hydrolysing activity of one neutrophilic and two acidophilic soil streptomycetes was studied in detail. The neutrophilic culture extract was active from pH 5.0 to pH 8.0, with optimum activity from pH 5.5 to 6.5. Acidophile activity occurred from pH 2.5 to 7.0 with an optimum at pH 4.0 to 4.5. After storage for 24 h at different pH levels, neutrophiles showed a sharp reduction in activity at pH 5.0 with none below this point; some activity was maintained up to pH 10.0. Acidophiles remained active after storage at pH 3.0 and retained some activity up to pH 7,0--9.0. Less detailed tests on a range of soil streptomycetes showed that the differences between acidophiles and neutrophiles were consistent. The results indicated that acidophilic streptomycetes may produce a range of exo-enzymes which are themselves acid-requiring and play an important part in decomposition processes in acidic soils and litters.
Changes in physiological reproductive states of female Long-Evans hooded rats were directly correlated with changes in the concentration of acidophilic and basophilic connective tissue granulated cells in the lamina propria of the duodenum. Acidophilic granulated cell numbers were significantly higher at estrus and metestrus than at other stages of the estrous cycle or in the immature state. apcidophilic granulated cell numbers during pregnancy were not significantly different from cell numbers quantified during metestrus, diestrus, or proestrus, but were significantly lower than cell numbers during estrus. Late lactation (21-25 days) was associated with significant decreases in the numbers of acidophilic granulated cells from numbers observed during the estrous cycle and during pregnancy. Basophilic granulated cell numbers did not differ significantly during the estrous cycle, although the highest numbers were observed during proestrus. Basophilic granulated cell numbers were significantly higher during pregnancy than during the estrous cycle. Basophilic granulated cell counts in late lactation were comparable to numbers quantified in estrus, metestrus, and diestrus, but were significantly lower than during proestrus and pregnancy.
Nonconventional yeasts represent a great genetic and phenotypic diversity with potential for industrial strain development in the bio-production of green chemicals. In recent years, mass genome sequencing of nonconventional yeasts has opened avenues to improved understanding of transcriptional networks and phenotypic plasticity and gene function, including the discovery of novel genes. Here, we investigated the expressional and morphological changes at low-pH in three strains of the acidophilic yeast Maudiozyma bulderi (previously Kazachstania bulderi and Saccharomyces bulderi): CBS 8638, CBS 8639, and NRRL Y-27205. The comparison of the transcriptome of cells growing in a bioreactor at pH = 5.5 vs pH = 2.5, primarily showed dysregulation of genes involved in cell wall integrity, with NRRL Y-27205 the least acidophilic strain, showing the largest transcriptional response when compared to the other strains. We identified four uncharacterized genes, unique to M. bulderi, and predicted function as transporters, upregulated at low pH. Microscopy studies showed that M. bulderi cell wall is not damaged in acidic environment, and the membrane lipid composition remains stable at low pH, unlike Saccharomyces cerevisiae. Overall, our data on transcriptional variability in M. bulderi highlights genes and cellular pathways involved in the acidophilic adaptation of this species and can aid further strain development.
Among 87 pituitary adenomas, four neoplasms had a superficial resemblance to undifferentiated cell adenomas and some fine structural features of both sparsely granulated adenomatous growth hormone and prolactin cells. Misplaced exocytosis, fibrous bodies, and multiple centrioles were sometimes revealed within the same cell and usually were accompanied by oncocytic transformation, mitochondrial alterations, and abnormal centriologenesis. The patients had normal or low blood growth hormone levels and elevated or normal prolactin values. All the tumors that were tested contained immunoreactive growth hormone and prolactin, irrespective of the blood hormone levels. The four tumors could represent a hitherto unclassified adenoma type and derive from the common, committed precursor of the two acidophils. The term acidophil stem cell adenoma is proposed to designate this entity.
The cells of pituitary adenomas classified as acidophilic on PAS-light green-orange G staining could be further differentiated with the Brookes technique: they stained nonspecifically bluish-gray, orange with orange G, or red with carmoisine. On immunostaining for growth hormone and prolactin, the gray cells were either negative or reactive for prolactin, the orange cells contained growth hormone, and the red cells contained prolactin. Of 28 tumors, eight showed no immunostaining, 11 stained only for prolactin, three stained only for growth hormone, five contained mostly growth hormone cells and some prolactin cells, and one contained predominantly prolactin cells but also numerous growth hormone cells. Immunoreactive growth hormone granules in adenoma cells were usually arranged randomly; prolactin granules were often concentrated along one nuclear pole. This study emphasizes the tinctorial and immunocytochemical heterogeneity of "acidophilic" adenomas.
A series of extremely thermophilic acidophilic bacteria has been characterized as closely resembling the species Sulfolobus acidocaldarius except for a totally different guanosine-cytosine content in the DNA; some conceptual consequences of this situation are discussed. Both organisms also share special features, including a very characteristic type of ether lipid, with other extreme acidophilic thermophiles.
Acid mine drainage (AMD) is characterized by persistent acidity, high sulfate and dissolved metal concentrations. Sulfate-reducing bacteria (SRB) are attractive candidates for AMD remediation because dissimilatory sulfate reduction generates alkalinity while producing sulfide that can facilitate metal removal through precipitation. Extending these processes to acidic conditions has increased interest in acidophilic and acid-tolerant SRB (aSRB and atSRB), yet evidence from cultivation, molecular surveys and treatment systems has often been interpreted separately. This systematic review synthesized 53 culture-dependent, culture-independent, and treatment system studies from 2014 to 2024 to examine relationships among taxonomic occurrence, physiological capability, demonstrated low-pH sulfate reduction and treatment performance. Phylogenetic analysis showed that low-pH sulfate-reducing phenotypes were distributed across multiple lineages and 16S rRNA relatedness alone did not predict acid tolerance. Desulfosporosinus was the most consistently represented genus across studies, although its recurrence was influenced by cultivation strategies. Sulfate reduction was demonstrated below pH 3, with sustained low-pH activity most strongly supported by controlled reactor studies; approximately pH 4.0-5.5 emerged as a comparatively well-supported range, while activity at lower pH was more dependent on microbial physiology and experimental conditions. Low-pH sulfate reduction also emerged as a community-level process shaped by electron-donor use, metabolite turnover and complementary microbial functions, while treatment performance additionally depended on biomass retention, hydraulic conditions and sulfide management. The reviewed studies support a distinction between taxonomic presence, demonstrated activity and treatment contribution. Future work should prioritize standardized reporting of active sulfate-reduction conditions, stronger taxon-function validation and long-term field testing of low-pH sulfidogenic systems.
Acidophilic, thermophilic bacteria were isolated from Japanese acidic hot springs. They were spore-forming rods, identified as Bacillus acidocaldarius. DNA extracted from these acido-thermophiles showed no abnormality in chemical structure; it was instantly denatured and gradually decomposed giving rise to apurinic acid in a hot acid environment milder than the optimal conditions for the growth of the acido-thermophiles. Glyceraldehyde-3-phosphate dehydrogenase extracted from B. acidocaldarius was not active at pH 5 or less, and was resistant to heat at neutral but not acid pH. The intracellular pH was computed to be neutral by using dimethyl-2,4-oxazolidinedione. When uncouplers or inhibitors of respiration were added to the cells suspended in hot acid solution, the estimated pH was not changed and glyceraldehyde-3-phosphate dehydrogenase in the cells was not denatured. These results suggest that the cytoplasm of B. acidocaldarius is a hot neutral environment, and that a pH gradient across the cell envelope can be maintained even when oxidative phosphorylation or respiration is inhibited.
An improved procedure for the purification of a lipid-containing acidophilic thermophilic bacteriophage, phiNS11, is described. The procedure involves Cs2SO4 discontinuous density gradient, Cs2SO4 equilibrium density gradient and sucrose gradient centrifugations. The phage has an icosahedral shape, 75 nm in diameter, with spike-like structures radiating from the vertices. It contained about 12% by weight of lipid, 13--14% of DNA and 74--75% of protein. The phage was stable between pH 2 and 5, but rapidly inactivated above pH 6. It was highly sensitive to organic solvents and detergents. Some other basic properties such as the buoyant density and UV spectrum of the purified phage are also described.
A new solid medium is described for growing iron and heterotrophic bacteria from acid mine drainage (AMD). Examination of AMD from five states revealed several kinds of colonies of iron-oxidizing bacteria: (i) smooth, (ii) smooth with secondary growth sectors or branching, (iii) star-shaped, (iv) radiating lobe, and (v) flat-rough. All AMD samples yielded whitish colonies that could not use ferrous iron, sulfur, or hydrogen, nor could they grow on nutrient agar, brain heart infusion agar, or Trypticase soy agar. Glucose and sucrose supported growth if the sugar-salts medium was at pH 3.0. The new iron medium has several advantages over others: (i) easy preparation, (ii) rapid growth, (iii) larger colonies, (iv) differentiation of colony morphology, and (v) detection of a new group of heterotrophic acidophilic bacteria.
The cyto-immunological tests prove that anti-ACTH (17-39) immunserums do not become localized only on beta cells of anterior lobe of Man's pituitary. They can also react upon cells with slender erythrosinophilic granules. Normally, these cells are very scattered. However, we have established that they were particulary numerous in the pituitary of six infants suddendly deceased. Conspicuously, these cells with acidophilic granulations correspond to a stage of corticotropic cells maturation.
An acidophilic thermotolerant strain of Candida utilis 1668-3-37 was produced under conditions of continuous cultivation during 128 days. The optimum pH is 3.0-4.5 at 32 degrees C. The strain grows with mumax=0.30 hr(-1) at 37-38 degrees C and the same pH values if dry yeast autolysate (0.05%) is added to the medium.
Obligate thermophilic acidophilic cultures of Bacillus acidocaldarius were isolated from hot springs and soil of the Kunashir Island (the Kuril Islands) and Southern Sakhalin; their optimum temperature of growth is 65 degrees C and pH is 3.3--4.0. It has been shown for the first time that these organisms can be isolated from springs with either acidic or neutral and weakly alkaline pH values.
The Fluorochrome Geranine G binds to acidophilic neurosecretory cells and produces red orange fluorescence. Chromolipids and pigments show green fluorescence. This method is easy and sensitive. Fluorescence fading during irradiation is low.
Basic proteins of the granules of mast cells in nativ, formalin-, alcohol- and aceton fixed preparations without any preliminary treatment, when stained with acidic dye at the pH 9 cytochemically seem to be masked. After various preliminary treatment (treatment with acid, with cetylpiridinumchlorid, CPC) mast-cell granula stained with acidic-dye at pH 9 appear intensively acidophile. This phenomenon can be explained by the presence of basic proteins in the mast cell granula. Preliminary treatment with CPC inhibits acid radicals of the heparin. This may lead to the disintegration of the linkage between proteins of the heparin, thus amino-group of the basic proteins become reactivated and can be identified by acidic dyes. It can not be excluded as well, that CPC linked to the heparin with free positive radicals reveals acidic-dye-binding capacity. In cases of preliminary treatment with various acids this mechanism does not seem possible to lay on the base of changing of the dye binding capacity.