Relationships between boron concentrations and trout in the Firehole River, Wyoming: historical information and preliminary results of a field study

The Firehole River (FHR) in Yellowstone National Park (YNP) is a world-renowned recreational fishery that predominantly includes rainbow trout (RBT,Oncorhynchus mykiss) and brown trout (BNT,Salmo trutta). The trout populations apparently are closed to immigration and have been self-sustaining since 1955. Inputs from hot springs and geysers increase the temperature and mineral content of the water, including elevating the boron (B) concentrations to a maximum of 1 mg B/L. Both RBT and BNT reside in warm-water reaches, except when the water is extremely warm (≥25°C) during midsummer. They spawn in late fall and early winter, with documented spawning of BNT in the cold-water reach upstream from the Upper Geyser Basin and of RBT in the Lower Geyser Basin reach, where water temperatures presumably are the warmest; however, successful recruitment of RBT in waters containing 1 mg B/L has not been demonstrated conclusively. Thus, we began investigating the relationships among temperature, B concentrations, other waterquality parameters, and the distribution and reproduction of trout in the FHR in spring 1997. However, atypical high water flows and concomitant lower than historical temperatures and B concentrations during summer 1997 preclude conclusions about avoidance of high B concentrations.     

The effect of alpha and beta adrenergic blockade on Ni induced coronary spasm in scalded rats

After 20% total body surface scalding inducing 3d degree burn in rats the following parameters were studied in ebb and flow phases, as well as in burn disease, 2 hours, 2 and 7 days postburn: atomic absorption spectrophotometric study of the serum and myocardial Ni levels; the effect of Ni ions (10(-8)-10(-4) M/l) in vitro on total coronary resistance in the isolated perfused rat heart; the effect of alpha and beta adrenergic blocking agents (phenoxibenzamine, oxprenolol) on Ni-induced coronary vasoconstriction; electron cytochemical study of the ultrastructural changes of the myocardium 7 days after scalding. It was found that: During the first 2-3 hours after scalding or bleeding there was a significant elevation of serum Ni level which levelled off by the end of the first week. Total coronary resistance (TCR) increasing effect of Ni ions was significantly augmented during the first 2-3 hours after burn and bleeding (ebb phase). In the scalded group it decreased to the control value by the 2-3d day (flow phase) and increased again a week later (burn disease). In the scalded groups in vivo pretreatment with oxprenolol (10(-4) g/kg) completely inhibited the Ni induced coronary spasm. PBZ treatment in vitro (10(-5) M/l) had similar effect in the three postburn periods tested. Ultrastructural changes and intracellular Ni-dimetilglyoxim complexes could be detected. Oxprenolol treatment continuously applied from the 4th day postburn (2 X 0.5 mg/kg) prevented the development of myocardial damage, while the electron dense complexes containing Ni were still detectable. In view of our previous data we assume that the endogenous Ni increase in the serum after burn may be cardiopathogenic. The phasic changes of the sensitivity of the coronary vessels to Ni ion and the similarity of the effects of alpha and beta adrenergic blocking agents may be explained by the alterations in the neuroendocrine system and metabolic disturbances.     

Dracaena Leaf Proliferosis, a Newly Recorded Disease Affecting Dracaena sanderiana in Egypt

Dracaena leaf proliferosis is a newly reported disease affecting Dracaena sanderiana in Egypt. A cause and effect relationship between this disease and the fungus,Fusarium proliferatum var. minus has been established. In addition to D. sanderiana the fungus was found to be pathogenic, when tested in the laboratory, to several other members of the family Liliaceae. While the in vitro growth of the fungus is optimum at 25 °C, symptom expression is best at 30°C. Twelve fungicides were tested for their in vitro effect on fungal growth. Benlate, Rubigan, Saprol, Cercobin and Vitavax-200 came first on the list and inhibited growth at 2.5, 12.0, 55.0, 75.0, and 94.0 μg/ml, respectively. Although, Benlate was the most effective fungicide in this respect it failed to demonstrate similar effect on disease development when applied to plants artificially inoculated with the fungus. Fungal growth was completely inhibited on PDA medium by a bacterium belonging to Bacillus sp. but when the bacterium at a concentration of 1 × 10¹¹ cell/ml was applied 24 h before, at the same time with, or 24 h after inoculation no control of the disease was achieved. Naturally-infected plants could, however, be freed from infection when subjected to a hot air treatment at 35 ± 5 °C during day time and 25 ± 5° C at night for 3 months.     

Polycyclic aromatic hydrocarbon residues in blood serum and human milk in Egypt,A pilot case study

This study was performed to monitor residues of polycyclic aromatic hydrocarbons (PAHs) in samples of human blood serum and human milk taken from volunteers from one rural area of Egypt. Extraction and clean-up processes were conducted using the Quick Easy Cheap Effective Safe methodology. PAH residue analysis was performed by Gas chromatography-flame ioninzation detector (GC-FID) and High performance liquid chromatography-fluorescence detector (HPLC-FLD) for blood and milk samples, respectively. Some confirmatory work was conducted using a mass spectrometer. The concentrations of PAH residues in blood samples were between 0.007 and 0.407 mg/l, with many of the congeners below detection limits. Residues of the most carcinogenic PAH congeners including benzo (a) pyrene were below the limits of detection in all blood samples, and total PAH concentrations have ranged between 0.156 and 3.61 mg/l. Regarding human milk samples, the sum of PAH concentrations ranged from 95.23 to 229.26 (µg/kg f.w.) with a mean of 154.35 (µg/kg f.w.). Benzo[a]pyrene was detected in concentrations ranging from 0.348 to 15.4, with a mean of 7.872 (µg/kg f.w.). Acenaphthylene, dibenzo [a,h]anthracene, acenaphthene, and naphthalene were the most abundant congeners in milk samples. Results indicated that the sources of PAHs in blood serum and human milk are of pyrogenic and petrogenic origin, respectively.     

Protein kinase C decreases the hepatocyte growth factor-induced activation of Erk1/Erk2 MAP kinases

HGF and phorbol ester induce the scattering of HepG2 cells. Recently, we have reported that the motility and morphological responses that accompany this process require the activation of Erk1/Erk2 MAP kinases, and phosphatidylinositol 3-kinase contributes to the activation of Erk1/Erk2 in HGF-induced cells. The cell scattering-associated appearance of a high-M(r) (>300 kDa) protein pair has also been observed, and has been proven to be a sensitive marker of the intensity of Erk1/Erk2 activation. Our present study demonstrates that in HGF-induced cells protein kinase C and phosphatidylinositol 3-kinase regulate oppositely the expression of these cell scattering-associated proteins. While in phorbol ester-treated cells the sustained activation of protein kinase C is essential for this expression, in HGF-induced cells the inhibition of protein kinase C with bisindolylmaleimide I stimulates the expression. Protein kinase C reduces the HGF-induced phosphorylation of Erk1/Erk2, and in this way it can limit the intensity of Erk1/Erk2-dependent gene-expression     

Cyclic AMP-dependent protein kinase stimulates the formation of polyphosphoinositides in the plasma membranes of different blood cells

Plasma membrane preparations from lymphocytes, platelets and red cells were phosphorylated in the presence of [gamma-32 P]ATP. The dissociated catalytic subunit of cyclic AMP-dependent protein kinase increased the 32P-labelling of proteins and polyphosphoinositides in lymphocyte, platelet and in some red cell membranes. In the majority of red cell membrane preparations the 32P-labelling of proteins and polyphosphoinositides seemed to be stimulated by the catalytic subunit of the endogenous protein kinase, since the phosphorylation was not increased by the addition of the catalytic subunit but it was decreased by the heat-stable inhibitor protein of the protein kinase. Different sets of 32P-labelled proteins were shown by SDS-gel electrophoresis in the membranes of the 3 cell types. A 24000-Mr protein was the only one which was phosphorylated by the catalytic subunit in each membrane.     

Bacillus mojavensis strain 32A, a bioflocculant-producing bacterium isolated from an Egyptian salt production pond

Bacillus mojavensis strain 32A that exhibited 96.11% flocculation efficiency for clay suspensions was selected from other 15 comparative strains. Under growth condition, strain 32A was able to produce 5.2 g/L of purified biopolymer. Its constituent was mainly polysaccharide and protein with proportional of 98.4-1.6% respectively. FTIR spectrum was confirming its chemical analysis. This biopolymer attain very fast sedimentation rate. The cost-effective biopolymer and CaCl₂ dosages were 3 mg/L and 5 ml/L respectively that posed 89.7% flocculation efficiency. These dosages were suitable only for clay concentrations ?5 g/L. The maximum flocculation efficiency of the biopolymer recorded at pH 1.0 of clay suspension. The too high (>75 °C) or too low (<25 °C) clay suspension temperature was unfavorable for the biopolymer flocculation performance. The biopolymer solution utilized high thermal stability over the temperature range of 5-60 °C. Furthermore, its pH stability recorded at pH range of 5-9.     

New carrier for specific delivery of drugs to the brain

1,4-Dihydropyridines were thoroughly investigated as carriers for specific drug delivery to the brain and were found very efficient. The main problem which arises in their application in pharmaceutical preparations, is the short shelf-life time due to hydration and/or oxidation. To overcome these problems, a new carrier system is suggested. Many of 1,4-dihydropyridine-3,5-dicarboxylate derivatives are used as calcium channel blockers which are known to have long shelf-life time, and at the same time, they are safe, with no reported neurotoxicity. Since efficiency of brain specific delivery depends on the rate of oxidation of the dihydropyridine carrier, (the faster the rate, the higher the efficiency), these 3,5-dicarbonyl compounds have almost of no brain-specific delivery properties. N-alkoxycarbonylmethyl derivatives of 1,4-dihydropyridine-3,5-dicarboxylate, a new carrier system is suggested and expected to be stable enough for formulation and storage. The drug moiety will be connected to the 3,5-dicarbonyl groups in the form of esters or amides. The suggested drug-carrier once delivered and distributed in the body, will be subjected to several sequential enzymatic hydrolytic and oxidative processes. The D-carrier is designed so that, the rate of hydrolysis of the ester group at the nitrogen atom should be faster than that of the hydrolysis and release of the drug moiety. The stability and efficiency of brain specific delivery of model drugs were investigated. The in vitro and in vivo studies proved the efficiency of brain specific delivery of the carrier and at the same time its shelf life stability. The results suggest that the designed carrier is promising to be used in application of pharmaceutical formulation.     

Phorbol ester-induced migration of HepG2 cells is accompanied by intensive stress fibre formation,enhanced integrin expression and transient down-regulation of p21-activated kinase 1

Previously, we observed that phorbol ester induced more intensive scattering of HepG2 human hepatoma cells than hepatocyte growth factor (HGF). Regulatory components accounting for this intensive migration were studied. Phorbol ester-activated protein kinase C induced the early appearance of a great number of actin stress fibres. Whereas in response to HGF, the activation of phosphatidylinositol 3-kinase initiates the rearrangements of the actin cytoskeleton, in phorbol ester-treated cells, the activation of this enzyme was not required to the actin polymerisation. Activation of Erk1/Erk2 MAP kinases that was essential to the migration had a key role in enhancing the adherence of cells to the extracellular matrix via the increased expression of integrins alpha2, alpha6 and beta1. Protein kinase C stimulated the activation of p21-activated kinase (PAK), as well. However, it also stimulated the selective and transient down-regulation of PAK1, which coincided with the formation of stress fibres.