Environmentally-induced cadmium tolerance in the grass Holcuslanatus L.

This paper reports results of a study on cadmium tolerance in the grass $\text{Holcus}$$\text{lanatus}$ which suggest that tolerance is inducible and can be lost in transplanting plants to uncontaminated soils.     

Biotransformation of the fungicide pentachloronitrobenzene by Tetrahymenathermophila

The protozoan, $\text{Tetrahymena}$$\text{thermophila}$, metabolizes pentachloronitrobenzene to several products, including nitrite, pentachlorothioanisole and pentachloroaniline. The latter two metabolites were identified by gas chromatographymass spectrometry. Pentachlorothioanisole may be produced via a glutathione-dependent pathway, and two key enzymes of this pathway, glutathione transferase and thiol S-methyltransferase, have been detected in crude extracts of this microorganism.     

Biotransformation of N-phenyl-β-naphthylamine to β-naphthylamine in a laboratory sludge system

$\text{N}$-Phenyl-$\text{β}$-naphthylamine, a widely used rubber antioxidant and antiozonant, was biotransformed into $\text{β}$-naphthylamine, a potent carcinogen, in a laboratory sewage sludge system. $\text{β}$-Naphthylamine appeared to accumulate in the aqueous phase of the system while the undegraded parent compound appeared to be associated with the sludge solids.     

Metabolites of diisopropylnaphthalene in carp Part 2. Invitro experiment

This study described an $\text{in}$$\text{vitro}$ experiment on biotransformation of 2,6-DIPN in carp hepatopancreas. It has already been revealed by the previous $\text{in}$$\text{vivo}$ studies to be metabolized with enzymatic oxidation in the liver and been postulated a metabolic pathway. These results were confirmed by means of incubation with 2,6-DIPN in carp hepatic microsome preparation with NADPH, and G-6-P as co-factor. It was suggested that DIPN may be mainly metabolized in the hepatic cytochrome P-450 in the microsomes system. The kinetic parameters i.e. apparent Michaelis constant (Km) and maximum velocity (Vmax), in the metabolites formation were also calculated.     

Uptake and bioaccumulation of three PCBs by Chlorellafusca

This paper reports the bioaccumulation of three PCBs (2,4′-dichlorobiphenyl, 2,4,6,2′-tetrachlorobiphenyl and 2,4,6,2′,4′-pentachlorobiphenyl) by the green alga $\text{Chlorella}$$\text{fusca}$ under various conditions. A probable pattern of the bioconcentration mechanism is suggested. No metabolites were extracted from algae or water 6 days after incubation with PCBs.     

Effect of fungicidal seed treatments on alfalfa growth and nodulation by Rhizobiummeliloti

A study of the effect of 5 fungicide seed treatments on alfalfa ($\text{Medicago}$$\text{sativa}$ L. var. Vernal) growth and nodulation by $\text{Rhizobium}$$\text{meliloti}$ 102F66 was conducted in a growth chamber. Captan, maneb and thiram exhibited greater toxicity to $\text{R}$. $\text{meliloti}$ and alfalfa plants than that of benomyl and zineb. Recovery of the inhibitory effect was rapid.     

Oxidative dealkylation of five phenylurea herbicides by the fungus CunninghamellaechinulataThaxter

Microorganisms isolated from soil degrade phenylurea herbicides via two major pathways: (i) direct hydrolysis by an amidase leading to N,O-dimethylhydroxylamine, CO₂ and aniline¹ and (ii) N-dealkylation, which has been described as the first step in urea herbicide degradation by a variety of organisms including mammals, plants and microbial systems (for a review see reference 2).Until now no attempts have been made to investigate the mechanism of N-demethylation of substituted ureas in soil microorganisms, due to the instability of the N-hydroxymethyl intermediates. This reaction mechanism has only been described in detail in green plants^3–5. As among soil fungi Phycomycetes are known to demethylate phenylurea herbicides^6,7 this study has been made to identify intermediate hydroxymethyl compounds from urea herbicides, when incubated with the fungus $\text{Cunninghamella echinulata Thaxter}$.     

Chlordane compounds residues in Weddell seals (Leptonychotesweddelli) from the Antarctic

Weddell seal samples taken from the Antarctic have been found to be contaminated with chlordane compounds. ΣChlordane ($\text{cis}\text{-chlordane}\text{+}\text{cis}\text{-nonachlor}\text{+}\text{trans}\text{-nonachlor}\text{+}\text{oxychlordane}$) was present in blubber of seals at the range of 12 - 62 ng/g fresh weight. The order of chlordane compound concentrations was $\text{trans}\text{-nonachlor}\text{>}\text{oxychlordane}\text{>}\text{cis}\text{-nonachlor}\text{>}\text{cis}\text{-chlordane}$. Relative aboundance of $\text{cis}$-chlordane in Σchlordane is higher than that in humans. A probable explanation for their occurrence in the Antarctic is an airborne transport.     

The effect of cadmium ion on the growth,photosynthesis, and nitrogenase activity of Anabaenainaequalis

The growth of $\text{Anabaena}$$\text{inaequalis}$ was significantly inhibited by Cd²⁺ concentrations greater than 0.02 ppm (μg/ml) and completely inhibited at 0.06 ppm (Day 12). Cadmium had no significant effect upon the lag phase of growth or the culture doubling time, but caused the retardation phase to arrive sooner. One ppm Cd²⁺ significantly inhibited the rates of both photosynthesis and acetylene reduction, by $\text{A}$. $\text{inaequalis}$, with complete inhibition at 4 and 20 ppm respectively. Cell sensitivity increased directly with exposure time. Cadmium caused some cell lysis of $\text{A}$. $\text{inaequalis}$ and induced an increase in filament length, heterocyst frequency, and a loss of cellular contents from filament apical cells. The cellular abnormalities observed and the fact that toxicity increased with longer exposure times, suggested that metal toxicity resulted from effects of Cd²⁺ taken up by cells rather than Cd²⁺ at the cell surface.     

Effects of some pesticides on Rhizobiomjaponicum and on the seed germination and pathogens of soybean

The relative toxicity of 23 pesticides, including 21 fungicides and two pyrethroid insecticides, on $\text{Rhizobium}$$\text{japonicum}$, four soybean pathogens, $\text{Fusarium}$$\text{oxysporum}$, $\text{Phytophthora}$$\text{megasperma}$, $\text{Phytophthora}$$\text{parasitica}$ and $\text{Pythium}$$\text{ultimum}$, and germination of soybean seeds was compared with a highly toxic broad spectrum germicide, HgCl₂ under laboratory conditions.     

Accumulation of bis(tributyltin) oxide by the mud crab, Rhithropanopeusharrisii

Accumulation of ¹⁴C labelled bis(tributyltin) oxide (TBTO) by the mud crab, $\text{Rhithropanopeus}$$\text{harrisii}$, was determined through short-term exposure to labelled water and food. The potential for trophic accumulation during chronic low level exposure is emphasized.     

Toxicity of mixtures of phosphamidon and methidathion to lobsters (Homarusamericanus)

The joint toxicity of mixtures of phosphamidon and methidathion to adult lobsters ($\text{Homarus}$$\text{americanus}$) is greater than additive in tests with the combined 48-h toxicity unit of the mixtures totalling 0.25, 0.5 and 1.0 units. The largest magnification factor for greater than additive toxicity occurred where phosphamidon and methidathion contributed to the total toxicity unit in a ratio of 1:1.5 and was progressively smaller for ratios of 1:4.4 and 2:1.     

Interaction of higher marine fungi with the herbicide atrazine. III. Adsorption of atrazine to the marine fungus Dendryphiellasalina

The adsorption of the herbicide ¹⁴C-atrazine to the marine fungus $\text{Dendryphiella}$$\text{salina}$ was studied using sodium azide as an inhibitor of active uptake. Adsorption of atrazine (94 ppb) was found to reach equilibrium within six hours. Adsorption as a function of concentration (9.4 to 468 ppb) conformed to the empirically derived Freundlich equation giving a K value of 6.2. Atrazine on the fungal cell surface was easily desorbed by successive artificial seawater washes indicating a relatively loose binding. The ability of the marine fungus $\text{D.}$$\text{salina}$ to remove ¹⁴C-atrazine from an artificial seawater medium suggests an environmental role in the transport and redistribution of atrazine in estuaries.     

Heavy metal pollution from a point source demonstrated by means of mussels, Mytilusedulis

Heavy metal pollution from a point source has been demonstrated by the levels of mercury in flesh of mussels, $\text{Mytilus}$$\text{edulis}$.     

Effect of cadmium and zinc on intestinal absorption of xylose and tryptophan in the fresh water teleost fish, Heteropneustesfossilis

The effect of cadmium and of zinc on the rate of uptake of a pentose sugar xylose and an aminoacid tryptophan by the intestine of a teleost fish, $\text{Heteropneustes}$$\text{fossilis}$ was studied under two experimental conditions. In the first, four concentrations of cadmium or zinc (1.0 mM, 0.1 mM, 0.01 mM and 0.001 mM) mixed with the nutrient solution were filled in the intestinal sacs, and the rate of absorption was recorded after 1 h at 23°C. In the second experiment fish were exposed by bath to a sublethal concentration of cadmium (0.26 mg/1) or zinc (4 mg/1) for 15 and 30 days and the rate of absorption of the two nutrients was measured. The activity of intestinal Na⁺, K⁺ activated adenosine triphosphatase was also assayed. The two heavy metals at all the four concentrations decreased the rate of intestinal transport of nutrients. Increase in the concentration of each of the heavy metals decreased the uptake of nutrients, but the decreases were not linear. The rate of intestinal absorption of the two nutrients was also reduced by exposure of fish to the heavy metals $\text{in}$$\text{vivo}$. The activity of Na⁺, K⁺ ATPase decreased $\text{in}$$\text{vitro}$ with all four concentrations of cadmium and zinc and was diminished in fish exposed for 15 and 30 days. Of the two heavy metals, cadmium was more effective in reducing the rate of transport of xylose and tryptophan.     

Effects of selected pesticides on Rhizobiummeliloti, and on seed germination and Verticillium wilt pathogens of alfalfa

Studies on the effects of 21 fungicides and five pyrethroid insecticides on growth of $\text{Rhizobium}$$\text{meliloti}$, emergence and survival of alfalfa seed and the efficacy of the chemicals in control of Verticillium wilt pathogens were conducted.     

Changes in the levels of aspartate and alanine aminotransferase activities of Anabastestudineus (Bloch) exposed to disyston

In $\text{Anabas}$$\text{testudineus}$, the per cent changes noted in the aspartate aminotransferase (AAT) activities of gill, brain, intestine, liver, muscle and kidney until 6 hr of exposure to lethal concentration (10.5 mg/L disyston) were relatively much less when compared to those of sublethal concentration (4.0 mg/L disyston). But in the case of alanine aminotransferase (AIAT) activity, the tissues which showed such effect (paradoxical effect) were gill, brain and liver.     

Hydrocarbons in Sand Crabs (Emeritaanaloga) from Southern California (U.S.A.)

$\text{Emerita}$$\text{analoga}$ (Crustacea:Hippidae) from three southern California (U.S.A.) beaches contained 0.9 to 24.1 μg/g dry wt saturated hydrocarbons, and 3.6 to 21.4 μg/g dry wt unsaturated hydrocarbons. Major constituents were (in wt. % total): n-alkanes (13.1%), heneicosapentaene plus heneicosahexaene (1.0%), squalene (5.1%), and unidentified polyenes (7.8%). Crabs from beaches exposed to small boat traffic and natural oil seepage were slightly and severely tainted, respectively, with petroleum hydrocarbons. Animals from San Nicolas Island (85 km offshore) contained only biogenic compounds.     

Aqueous solubility of polychlorinated dibenzo-p-dioxins determined by high pressure liquid chromatography

Water solubilities (S_W) determined by the HPLC generator column method are reported for a series of chlorinated dibenzo-$\text{p}$-dioxins (PCDDs) with S_W ranging from 0.4 ng/L (ppt) for octa-chlorodibenzo-$\text{p}$-dioxin to 430 ng/L for 1,2,3,7-tetrachlorodibenzo-$\text{p}$-dioxin at 20°C. A correlation is demonstrated between S_W and HPLC capacity factors (k′) for these extremely hydrophobic compounds, allowing calculation of S_W of PCDDs from k′ and melting point data.     

Mercury induced alterations in the intestinal,absorption of nutrients in the fresh water murrel, Channapunctatus

The effect of five concentrations (10 mM, 1 mM, 0.1 mM, 0.01 mM and 0.001 mM) of mercury on the rate of absorption of glucose, fructose, glycine and tryptophan by the intestine of the fresh water murrel $\text{Channa}$$\text{punctatus}$ has been studied. Intestinal absorption of these nutrients was also examined in fish exposed to a sublethal concentration (3 μg/l) of mercury for 15 and 30 days. Significant decrease was recorded in the rate of intestinal absorption of all the four nutrients with higher concentrations (10 mM, 1 mM and 0.1 mM) of mercury. 0.01 mM and 0.001 mM of mercury also reduced the transport rate but it was insignificant, except in case of tryptophan, where 0.01 mM of mercury also produced significant decrease. Exposure of fish by bath to mercury also resulted in significant decrease in the intestinal transport rate of all the four nutrients after 30 days.