Ultrastructural localization of adenosine triphosphatase activity in HeLa cells at various stages of the cell cycle

Summary HeLa cells in a monolayer culture were synchronized to S, G₂ and mitotic phases by use of excess (2.5 mM) deoxythymidine double-block technique. The localizations of Ca⁺⁺-activated adenosine triphosphatase (ATPase) at different phases of the cell cycle were studied using light and electron-microscopic histochemical techniques, and microphotometric comparisons of the densities of reaction products. Enzyme reaction product was always localized in the endoplasmic reticulum, nuclear membrane, mitochondria and Golgi apparatus, but there were qualitative and quantitative differences related to the phases of the cell cycle. In S phase the activity was mainly concentrated in a perinuclear area of the cytoplasm whereas in G₂ and mitosis the activity was scattered throughout the cell. The total activity per cell was maximal in G₂, was less in S phase and least in mitosis. Activity in the mitochondria and endoplasmic reticulum was distinctly less in mitosis than in other phases of the cell cycle. The mitochondrial ATPase differed from the ATPase at other sites in ion dependence and sensitivity to oligomycin. The results suggest that there may be several distinct ATPases in proliferating cells.     

A new species ofConiochaetidium from soil

A new species ofConiochaetidium isolated from soil of Iraq is described. The speciesC. nuciforme differs fromC. savoryi in the shape and size of the ascospores. A key to differentiate the accepted species of the genus is reported.     

Wistar Rats Resistant to the Hypertensive Effects of Ouabain Exhibit Enhanced Cardiac Vagal Activity and Elevated Plasma Levels of Calcitonin Gene-Related Peptide

Ouabain is a cardiac glycoside produced in the adrenal glands and hypothalamus. It affects the function of all cells by binding to Na⁺/K⁺-ATPase. Several lines of evidence suggest that endogenous ouabain could be involved in the pathogenesis of essential (particularly, salt-sensitive) hypertension. However, information regarding the postulated hypertensive effect of the long-term administration of low-dose exogenous ouabain is inconsistent. This study was designed to help settle this controversy through the use of telemetric monitoring of arterial blood pressure and to elucidate the ouabain-induced alterations that could either promote or prevent hypertension. Ouabain (63 and 324 µg/kg/day) was administered subcutaneously to male Wistar rats. Radiotelemetry was used to monitor blood pressure, heart rate and measures of cardiovascular variability and baroreflex sensitivity. The continuous administration of ouabain for 3 months did not elevate arterial blood pressure. The low-frequency power of systolic pressure variability, urinary excretion of catecholamines, and cardiovascular response to restraint stress and a high-salt diet as well as the responsiveness to α1-adrenergic stimulation were all unaltered by ouabain administration, suggesting that the activity of the sympathetic nervous system was not increased. However, surrogate indices of cardiac vagal nerve activity based on heart rate variability were elevated. Molecular remodeling in mesenteric arteries that could support the development of hypertension (increased expression of the genes for the Na⁺/Ca²⁺ exchanger and Na⁺/K⁺-ATPase α2 isoform) was not evident. Instead, the plasma level of vasodilatory calcitonin gene-related peptide (CGRP) significantly rose from 55 (11, SD) in the control group to 89 (20, SD) pg/ml in the ouabain-treated rats (P_Tukey''s = 18.10⁻⁵). These data show that long-term administration of exogenous ouabain does not necessarily cause hypertension in rodents. The augmented parasympathetic activity and elevated plasma level of CGRP could be linked to the missing hypertensive effect of ouabain administration.     

Effect of dietary selenium, zinc and allopurinol supplements on plasma and tissue manganese levels in rats with thiocetamide-induced liver cirrhosis

The effect of thiocetamide-induced liver cirrhosis on plasma and tissuemanganese levels and the protective role of selenium, zinc and allopurinolsupplements was investigated in rats. Control plasma and liver manganese(Mn) levels were found to be (mean ± SD): 8.4 ± 2.4 mg/L and5.7 ± 1.5 mg/g wet weight respectively. Plasma manganese levels weresignificantly increased (p < 0.001) whereas liver manganese levels weresignificantly reduced (p < 0.05) in the cirrhotic rats. Treatment withselenium, zinc and allopurinol reversed this trend and restored themanganese levels close to the normal values. Lung, spleen, and kidneymanganese levels under control conditions were considerably lower than thatof the liver tissue. However, these levels registered a significant increase(p < 0.05) in cirrhotic rats and this change was normalized after selenium,zinc and allopurinol treatment. There were no significant differences in thecomparative efficacy of each of these protective agents. Zinc supplementconsiderably increased the plasma zinc levels and plasma Zn/Mn ratio had agood correlation with plasma zinc concentration. This ratio wassignificantly reduced in cirrhotic rats, but returned to the control levelafter zinc, selenium and allopurinol treatment. The results of this studyindicate that the trace element, manganese, plays an important role instabilizing cell structure and that this effect is mediated possibly bypreserving the antioxidant activity of the tissues.     

Assessment of Urinary Iodine Excretion Among Normal Kuwaiti Adults

This study was performed to investigate the status of iodine intake among the Kuwaiti population and its effect on thyroid function. The study group was comprised of 139 females and 86 males with a mean age of 33 and 35 years, respectively. Urinary iodine excretion (UIE) and serum free T4 (FT4), thyrotropin hormone (TSH), antiperoxidase antibodies (anti-TPOAb), and antithyroglobulin antibodies (anti-TGAb) were determined. Median UIE was 148 µg/L (within the recommended level by the World Health Organization [WHO]). However, UIE levels of <100 and <50 µg/L were detected in both male and female groups, respectively. Serum levels of TSH and FT4 were normal for all except one of the participants who suffered from hyperthyroidism, possibly as a result of elevated iodine intake, which was reflected in an increased UIE of 590 µg/L. Elevated anti-TPOAb >75 IU/mL and anti-TGAb >150 IU/mL were detected in 15% and 34% of subjects; only 10% of them had elevated levels of both anti-TPOAb and anti-TGAb. Thus, based on the WHO recommendations, the iodine intake for the Kuwaiti population is adequate. However, it is recommended that a national study be conducted by the appropriate authority in order to eliminate any artifacts which may have appeared in this study.     

Serum changes in trace elements during thyroid cancers

The objective was to examine changes in trace elements due to thyroid cancer in humans. Serum levels and tissue contents of trace elements (Zn, Cu, Mn, Mg, Fe and Se) were measured in 43 patients with thyroid cancer before and 4 days after surgery were compared to normal values. The serum levels of zinc in cancer patients were lower than those of normal subjects. Surgical removal of the cancer resulted in the restoration of these levels. Although serum Cu levels in patients were not different from normal, but post-operatively these levels rose significantly (p < 0.001). Levels of Fe, Mg and Mn were significantly lower (p < 0.001) post-operatively. There was no significant change in Serum Se levels. The thyroid tissue contents of these trace elements did not show a difference between the normal (Juxta-tumor) thyroid tissue and the cancerous lesion. Out of the six trace elements examined, the decrease of serum levels of zinc in cancer patients may be linked to the disease condition. It is suggested that this change: (a) may be used to demonstrate successful cancer surgery and (b) may have implications for a long-term follow-up of thyroid cancer patients.     

Subsurface Associations of Acaryochloris-Related Picocyanobacteria with Oil-Utilizing Bacteria in the Arabian Gulf Water Body: Promising Consortia in Oil Sediment Bioremediation

Two picocyanobacterial strains related to Acaryochloris were isolated from the Arabian Gulf, 3 m below the water surface, one from the north shore and the other from the south shore of Kuwait. Both strains were morphologically, ultrastructurally, and albeit to a less extend, phylogenetically similar to Acaryochloris. However, both isolates lacked chlorophyll d and produced instead chlorophyll a, as the major photosynthetic pigment. Both picocyanobacterial isolates were associated with oil-utilizing bacteria in the magnitude of 10⁵ cells g^?1. According to their 16S rRNA gene sequences, bacteria associated with the isolate from the north were affiliated to Paenibacillus sp., Bacillus pumilus, and Marinobacter aquaeolei, but those associated with the isolate from the south were affiliated to Bacillus asahii and Alcanivorax jadensis. These bacterial differences were probably due to environmental variations. In batch cultures, the bacterial consortia in the nonaxenic biomass as well as the pure bacterial isolates effectively consumed crude oil and pure aliphatic and aromatic hydrocarbons, including very high-molecular-weight compounds. Water and diethylether extracts from the phototrophic biomass enhanced growth of individual bacterial isolates and their hydrocarbon-consumption potential in batch cultures. It was concluded that these consortia could be promising in bioremediation of hydrocarbon pollutants, especially heavy sediments in the marine ecosystem.     

Expression of estrogen receptor α and β in rat astrocytes in primary culture: effects of hypoxia and glucose deprivation

Estrogen replacement therapy could play a role in the reduction of injury associated with cerebral ischemia in vivo, which could be, at least partially, a consequence of estrogen influence of glutamate buffering by astrocytes during hypoxia/ischemia. Estrogen exerts biological effects through interaction with its two receptors: estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), which are both expressed in astrocytes. This study explored effects of hypoxia and glucose deprivation (HGD), alone or followed by 1 h recovery, on ERα and ERβ expression in primary rat astrocyte cultures following 1 h exposure to: a) 5 % CO(2) in air (control group-CG); b) 2 % O(2)/5 % CO(2) in N(2) with glucose deprivation (HGD group-HGDG); or c) the HGDG protocol followed by 1 h CG protocol (recovery group-RG). ERα mRNA expression decreased in HGDG. At the protein level, full-length ERα (67 kDa) and three ERα-immunoreactive protein bands (63, 60 and 52 kDa) were detected. A significant decrease in the 52 kDa band was seen in HGDG, while a significant decrease in expression of the full length ERα was seen in the RG. ERβ mRNA and protein expression (a 54 kDa single band) did not change. The observed decrease in ERα protein may limit estrogen-mediated signalling in astrocytes during hypoxia and recovery.     

Activation of human dendritic cells by the PorA protein of Neisseria meningitidis

The major porin proteins present in the outer membrane of Neisseria meningitidis, the causative agent of life‐threatening meningitis and septicaemia, are believed to have potent immunostimulatory effects. In this study, the interactions between human monocyte‐derived dendritic cells (mo‐DC) and the PorA porin were investigated, in order to reveal the role of this protein in promoting innate and adaptive immune responses. Recombinant (r)PorA induced mo‐DC maturation, as reflected by reduced receptor‐mediated endocytosis, increased production of the chemokines IL‐8, RANTES, MIP‐1α and MIP‐1β and augmented expression of the surface markers CD40, CD54, CD80, CD86 and major histocompatibility complex class II molecules. However, rPorA induced either low level or no significant secretion of pro‐inflammatory cytokines from mo‐DC. The protein potently augmented the capacity of mo‐DC to activate both allogeneic CD4⁺ memory T‐cells and CD4⁺RA⁺ naïve T‐cells. In addition, rPorA appeared to inhibit the production of IL‐12p70 that follows from the interaction between CD40 on the mo‐DC and CD40‐ligand on T‐cells, thereby directing T‐cell differentiation towards a Th2 type response. These data demonstrate that PorA is involved in DC activation and in influencing the nature of the T‐helper immune response, which are important properties for generating antibody responses required for protective immunity against meningococci and for determining the immuno‐adjuvant effects of this protein.     

Serum changes in trace elements during thyroid cancers

The objective was to examine changes in trace elements due to thyroid cancer in humans. Serum levels and tissue contents of trace elements (Zn, Cu, Mn, Mg, Fe and Se) were measured in 43 patients with thyroid cancer before and 4 days after surgery were compared to normal values. The serum levels of zinc in cancer patients were lower than those of normal subjects. Surgical removal of the cancer resulted in the restoration of these levels. Although serum Cu levels in patients were not different from normal, but post-operatively these levels rose significantly (p < 0.001). Levels of Fe, Mg and Mn were significantly lower (p < 0.001) post-operatively. There was no significant change in Serum Se levels. The thyroid tissue contents of these trace elements did not show a difference between the normal (Juxta-tumor) thyroid tissue and the cancerous lesion. Out of the six trace elements examined, the decrease of serum levels of zinc in cancer patients may be linked to the disease condition. It is suggested that this change: (a) may be used to demonstrate successful cancer surgery and (b) may have implications for a long-term follow-up of thyroid cancer patients.