Interactions of chlorinated hydrocarbon pesticides with the 8S estrogen-binding protein in rat testes

The effect of certain DDT analogs on the binding of ³H-estradiol to the 8–9S estrogen binding protein of rat testicular cytosol was studied by sucrose sedimentation analysis. The binding of ³H-estradiol to testicular cytosol was inhibited by o,p'DDT, a DDT analog which is estrogenic in the intact female, but not by p,p'DDE which is a nonestrogen in the female. The pesticide methoxychlor, which is estrogenic $\text{in vivo}$ in the female, failed to inhibit ³H-estradiol binding, presumably requiring metabolic activation for binding to the testicular cytosol. In fact, its di-demethylated metabolite 2,2-bis(p-hydroxyphenyl)-1, 1,1-trichloroethane (HPTE), also estrogenic $\text{in vivo}$, caused $\text{marked}$ suppression of ³H-estradiol binding.     

Influence of pesticides on the growth of cyanobacteria.

Two unicellular and two filamentous cyanobacteria (blue-green algae) were exposed under conditions optimal for photoautotrophic growth to eleven pesticides. Low concentrations (0.01 to 5 ppm) of diuron, atrazine, and paraquat inhibited growth. With MCPA, MCPP, 2,4-D, milstem and ethrel, marked inhibitory effects were achieved only at concentrations above 100 ppm. Growth was inhibited by glyphosate, DDT, and thiram at intermediate concentrations. In some cases, the effective concentration of the pesticide varied considerably with the organism tested.     

Monotertiarybutylhydroquinone effects on Tetrahymena pyriformis.

The molecular toxicity of monotertiarybutylhydroquionone (TBHQ) was studied using $\text{Tetrahymena}$$\text{pyriformis}$ as a model cell system. TBHQ at 26 ppm in the media inhibited cell growth by 50%. TBHQ inhibited the oxidation of ¹⁴C-acetate to ¹⁴CO₂. In addition, increasing concentrations of TBHQ decreased the incorporation of ¹⁴C-acetate into lipids and protein, ¹⁴C-amino acids into protein, ³H-uridine into RNA and ³H-thymidine into DNA. The incorporation of ¹⁴C-acetate into glycogen increased with concentrations up to 20 ppm TBHQ in the media while glycogen synthesis decreased with 40 ppm TBHQ.     

Phagocytic activity of Dictyostelium amoebae treated with an organochlorine pesticide.

The effect of an organochlorine pesticide benzene hexachloride (containing α, β, γ and δ isomers) on the phagocytic activity of the vegetative cells of Dictyostelium discoideum was investigated. Benzene hexachloride (BHC) at concentrations of 60 ppm and above inhibited the phagocytic activity as revealed by ³H-labelled E. coli uptake. The BHC treated cells also showed smaller and delayed plaque formation. Interactions of lipophilic pesticide with the hydrophobic cell surface presumably alters the receptor mediated phagocytosis of Dictyostelium amoebae.     

Zooplankton-induced unicell-colony transformation in Scenedesmus acutus and its effect on growth of herbivore Daphnia

The effects of colonial ecomorphs of the green alga Scenedesmus acutus on growth of Daphnia cucullata and D. pulex were examined. In ecologically relevant densities (up to 200 animals l^-1) the relatively small D. cucullata did not induce colony formation in Scenedesmus acutus, whereas the larger congener D. pulex significantly promoted colony formation. Both clearance rate and population growth rate (r) were significantly lower in D. cucullata when fed colonial Scenedesmus then when fed unicellular food. However, for D. pulex no effects of food type were observed. These results show that large Daphnia may influence its food in such a way that smaller congeners and competitors are negatively affected.     

Seasonal patterns of food limitation in Daphnia galeata: separating food quantity and food quality effects

Food limitation for the cladoceran Daphnia galeta was measuredgrowing them with natural lake seston for one growing seasonunder standardized conditions in the laboratory. Growth rateswere related to several measures of food quantity. Particulateorganic carbon (POC) <30 µm was the best predictorof total food availability measured. It was better than chlorophyll-a(Chl-a) of the same size fraction, algal volume calculated fromcell counts or total particle volume from Coulter Counter measurements.Daphnids were also grown with Scenedesmus acutus under the sameconditions and their growth rates were compared. Sestonic carbonconcentrations were related to Scenedesmus carbon concentrations,that provided equal growth rates. The ratio of the carbon concentrationsof both food types (seston, Scenedesmus) represented the foodquality of seston. Thus, the nutritional quality of naturallake seston relative to a standard alga was determined overone growing season. Growth rates of seston fed animals revealedthat they were food limited during long periods of the year.This was also ascertained by standard clutch sizes of fieldanimals. However, the causes of food limitation varied withinthe duration of the studied period. Whereas during the clear-waterphase the food quantity was limiting (while the quality washigh: 100% Scenedesmus), shortly after on 10 June and 17 Junefood conditions were close to threshold concentrations due tolow food quality. For the remainder of the summer, a POC of0.3–0.6 mg C I^–1 with a quality of     

DDT inhibition of Ca-Mg ATPase from peripheral nerves and muscles of lobster, Homarus americanus

Sensitivity of CaMg ATPase from axonic plasma membrane (APM) and sarcoplasmic reticulum (SR) of lobster, $\text{Homarus}\text{,}\text{americanus}$, to DDT was studied. The CaMg ATPase found in SR with the high Ca²⁺ affinity is sensitive to DDT while the portion of ATPase related to the low Ca²⁺ affinity site is not inhibited by DDT. Also, DDT is more inhibitory against the CaMg ATPase prepared from APM than the one obtained from SR. The relationship between inhibition of the CaMg ATPase by DDT in the axonic nerve membrane and $\text{in}\text{,}\text{vivo}$ poisoning symptoms of the nervous system is discussed.     

The detection of a bound ferredoxin in the photosynthetic lamellae of blue-green algae and other oxygen evolving photosynthetic organisms

The presence of an electron transport component with an EPR spectrum similar to that of a ferredoxin has been demonstrated in the blue-green alga $\text{Anabaena}$$\text{cylindrica}$, the green alga $\text{Euglena}$$\text{gracilis}$, and in chloroplasts from sorghum ($\text{Sorghum}$$\text{bicolour}$) and beans ($\text{Phaseolus}$$\text{vulgaris}$). The component is photoreduced at 77°K and is very similar to that previously reported in spinach. It seems likely that this component is a primary electron acceptor in photosynthesis in all of these organisms.     

D-Ribulose 1, 5-diphosphate carboxylase from blue-green algae

D-Ribulose 1, 5-diphosphate carboxylase has been purified to a state of homogeneity from the marine blue-green alga $\text{Agmenellum}$$\text{quadruplicatum}$ strain PR-6. The enzyme has been found to be easily separated from the bulk soluble protein by means of centrifugation into a sucrose gradient. RuDP carboxylase from $\text{Agmenellum}$, upon chromatography using a calibrated Sephadex G-200 column, exhibits a molecular weight of 456,000 daltons, considerably smaller than the protein from eucaryotic algae. Only one polypeptide of approximately 56,000 daltons was obtained upon dissociation in sodium dodecylsulfate.     

Ribonucleotide reductase activity in green algae

A ribonucleoside diphosphate reductase is demonstrated in the algae, $\text{Scenedesmus}\text{obliquus}$ and $\text{Chlorella}\text{pyrenoidosa}$. In synchronized cultures an activity maximum at the 12th hour of the cell cycle coincides with maximum DNA production. Induction of reductase activity is prevented by cycloheximide. The enzyme requires dithiols for reduction of CDP $\text{in}\text{vitro}$; it is not significantly stimulated by iron or magnesium ions nor dependent upon deoxyadenosylcobalamin. ATP stimulates the reaction but dATP or dTTP act as inhibitors. The ribonucleotide reductase of green algae differs from the B₁₂-requiring enzyme characterized in $\text{Euglena}\text{gracilis}$.     

Morpho-physiological aspects of Scenedesmus acutus PVUW12 cultivated with a dairy industry waste and after starvation

Among green microalgae, Scenedesmus sp. is known for its potential in wastewater remediation and lipid production, especially under starvation. Moreover, it is often characterised by a mixotrophic metabolism. In this work, we cultivated S. acutus PVUW12 in the presence of a liquid fraction of scotta (LFS), a cheese whey by-product, as source of nutrients. Subsequently, cultures were starved to evaluate lipid production. Cells were analysed to obtain information about growth, nutrient consumption during LFS cultivation, morphology and photosynthetic efficiency. We found that the alga boosted its growth when cultured in presence of LFS. Production of stromatic starch grains, polyphosphate granules, cell wall enlargement and reduction of the photosynthetic efficiency were also induced. Massive lipid accumulation was observed only during starvation, which also induced a strong slowdown of growth, loss of polyphosphate grains and further decrease in photosynthetic efficiency. This study demonstrates that S. acutus PVUW12 can be involved in a two-step cultivation, first by promoting growth using a by-product from cheese industry and second by transferring the microalgae on starvation to induce lipid accumulation for bioenergetics purposes.     

A laboratory study on the demography and competition of three species of littoral cladocerans from Lake Huetzalin,Xochimilco, Mexico

Lake Huetzalin (Xochimilco) is a shallow waterbody in Mexico City with a dominance of the littoral cladocerans Simocephalus vetulus, Alona rectangula, and Pleuroxus aduncus. Here, we present data on the life table and population dynamics of these three cladoceran species on two types of diets (alga Scenedesmus acutus and detritus). We also analyzed the effect of competition on population growth using Scenedesmus, which proved to be the better diet than detritus. We hypothesize that feces of the larger cladoceran species (S. vetulus) could be a food source for the smaller taxa (A. rectangula and P. aduncus). Experiments were conducted in 100 ml beakers with 50 ml of medium in each at a temperature of 23 ± 1°C. We studied the demography of three test species using two food types with four replicates for each treatment in the life table experiments. Based on the data thus obtained we further studied the competition between the cladocerans on a diet of Scenedesmus. The maximal growth rates obtained for P. aduncus, S. vetulus, and A. rectangula fed Scenedesmus acutus were: 0.1, 0.3, and 0.5 d⁻¹, respectively. Among the test species, S. vetulus had the highest survivorship of 77 days when cultured on detritus and P. aduncus the lowest of 20 days on Scenedesmus. The gross reproductive rate (offspring female⁻¹ lifespan⁻¹) ranged from 6 neonates in Pleuroxus to 160 in Simocephalus per female. From the competition experiments conducted using alga as the diet, we observed that A. rectangula and, especially P. aduncus, had higher growth rates in the presence of S. vetulus than in the controls. This facilitation could be one of the reasons for higher species diversity in the littoral of water bodies.     

Electron-dense Regions in Dividing Mitochondria of a Green Alga, Scenedesmus acutus

The dividing and the constricted regions of mitochondria ina green alga, Scenedesmus acutus , were studied by electronmicroscopy. Electron-dense substances were always visible inthese specific regions of mitochondria that had been fixed byfreeze-substitution. Thin fibres, which seemed to surround theconstricted regions, were also seen. The possibility that theelectron-dense regions constitute part of the dividing apparatusof the mitochondria is discussed.Copyright 1993, 1999 AcademicPress Division apparatus, division of mitochondria, electron microscopy, mitochondria, Scenedesmus     

Interaction of DDT (1,1,1-trichloro-2,2-BIS(p-chlorophenyl)-ethane with liposomal phospholipids

The influence of $\text{1,1,1-}\text{trichloro}\text{-2,2-}\text{bis}\text{(p-}\text{chlorophenyl}\text{)}\text{ethane}$ (DDT) and several other pesticides on the physical state of membrane phospholipids was investigated using model lipids. The thermal dependence of fluorescence intensity of the probe parinaric acid in dipalmitoylphosphatidylcholine liposomes and lipid vesicles of mixed composition were recorded. DDT was incorporated into the liposomal bilayer. The insecticide lowered the phase transition temperature and broadened the temperature range of the transition. The effects were concentration-dependent.The results may be interpreted as a sort of blurred and facilitated phase transition of bilayer lipids caused by intercalation of DDT between fatty acyl chains of membrane phospholipids.     

Ammonia: basis for algal symbiosis in salamander egg masses

The nitrogenous waste product ammonia, excreted by laval stages of the salamander, $\text{Ambystoma gracilis}$ (Baird), is removed from the perivitelline fluid by a symbiotic green alga, $\text{Chlamydomonas}$ sp. The alga stores the excess nitrogen as membrane-bound proteinaceous bodies, which partially explains the accelerated rate of development in the algal-inhabited egg masses.     

Effect of pesticides on blue-green algae

Summary Effect of pesticides, i.e., Benzene Hexachloride, Lindane, Diazinon and Endrin that are often used in India was observed on nitrogen-fixing blue-green algae Cylindrospermum sp., Aulosira fertilissima Ghose and aerobically non-nitrogen-fixing blue-green alga Plectonema boryanum strain 594. These algae were sensitive for BHC in comparison to other pesticides. A. fertilissima and P. boryanum were more resistant than Cylindrospermum sp.     

Anomalies in 5'-end [32P] labelling of transfer RNA and partial sequence of a tRNAGlu from Scenedesmus obliquus

A chloroplast tRNA_m^Met species from $\text{Scenedesmus}\text{obliquus}$ is very poorly 5′-end [${}^{32}\text{P}$] labelled using [γ-³²P]ATP and T4 polynucleotide kinase. In sequencing the tRNA using standard 5′-labelled methods a very minor contaminating tRNA is preferentially labelled. The partial tRNA sequence determined by this method has an anticodon (CUC) for tRNA^Glu.     

A novel in vitro method for demonstrating proestrogens. Metabolism of methoxychlor and o,p'DDT by liver microsomes in the presence of uteri and effects on intracellular distribution of estrogen receptors.

A method for demonstrating proestrogens $\text{in}$$\text{vitro}$ has been developed. The method involves the incubation of the potential proestrogen with liver microsomes and NADPH in the presence of rat uteri, followed by examination of the effects of metabolism of the compound on the distribution of uterine estrogen receptor (R) in the cytosol (R_c) and in the nucleus (R_n). Thus, we examined whether DDT derivatives, which possess estrogenic activity $\text{in}$$\text{vivo}$, exhibit pro-estrogenic properties $\text{in}$$\text{vitro}$. Using this method, it appears that methoxychlor is a proestrogen, since the presence of microsomal enzymatic activity is required for methoxychlor to elicit translocation of uterine R_c into the nucleus, namely, the lowering of R_c and elevation of R_n. By contrast, o,p'DDT was active $\text{per}$$\text{se}$ in translocating R_c and did not require the presence of microsomal enzymes for activity.     

Characterization of the phase behavior of phosphonolipids in model and biological membranes by 31P-NMR

³¹P-NMR is used to characterize the phase behavior of phosphonolipids in both model and biological membranes. ($\text{1′,2′-}\text{Dipalmitoyl}\text{-sn-}\text{glyceryl)-2-aminoethylphosphonate}$ gives rise to static chemical shift tensor elements (?87, 5 and 63 ppm) which differ considerably from those reported for the analogous phospholipid, $\text{1,2-}\text{dipalmitoyl}\text{-sn-}\text{glycero-3-phosphoethanolamine}$ (?81, ?20 and 105 ppm). Phosphonolipid, as well as a mixture of phosphonolipid and $\text{1,2-}\text{dipalmitoyl}\text{-sn-}\text{glycero-3-phosphocholine}$, in aqueous dispersion gives rise to ³¹P spectra which may be interpreted in terms of lamellar structures. A mixture of phosphonolipid and egg phosphatidylethanolamine exhibits a bilayer-to-hexagonal phase transition with a concomitant decrease by one-half in the value of the ³¹P chemical shift anisotropies of both the phosphonate and phosphate resonances. The chemical shift anisotropy associated with phosphonolipid has been found to be consistently smaller than that observed for the analogous phospholipid. ³¹P-NMR spectra of total lipid extracts of Tetrahymena sp. indicate that both phospho- and phosphonolipids have a bilayer organization between ?20 and 20°C.     

Crude oil effects on microsomal mixed-function oxidase system components in the striped mullet (Mugil cephalus)

The effects of exposure to two types of crude oil on microsomal mixed-function oxidase system components in livers of juvenile striped mullet ($\text{Mugil cephalus}$) were investigated. Mullet were exposed for 4 days to emulsified Empire Mix or Saudi Arabian crude oils at an initial concentration of 75 ppm and an average of 1 ppm in the water column. Liver size was increased by about 50% following exposure to both oils. Since neither total hepatic protein nor microsomal protein increased as rapidly as did liver size, the concentrations of both were reduced following oil exposures. The proportion of microsomal protein to total hepatic protein or wet weight was not altered following crude oil exposure. Both cytochromes P-450 and $\text{b}$₅ were induced following oil treatment. NADPH-dependent enzymes assayed with cytochrome $\text{c}$ and dichlorophenolindophenol as substrates showed increases in activity after exposure to Empire Mix crude oil but only the latter enzyme activity was increased on a microsomal protein basis following Saudi Arabian crude oil treatment. Activities of NADH cytochrome $\text{c}$ and NADH cytochrome $\text{b}$₅ reductases appeared to vary with the protein level. However, since liver size was increased, oil-treated mullet had more of all parameters measured than did control mullet. Although the acute toxicity of Saudi Arabian crude oil to mullet is greater than that of Empire Mix crude oil, Empire Mix crude oil had greater inductive effects on microsomal oxidase components.