Influence of Particle Size Distribution and Content of Organic Matter on the Toxicity of Copper in Sediment Bioassays Using Caenorhabditis Elegans (Nematoda)

The influence of particle size distribution and organic matter on the toxicity of copper was investigated using the nematodeCaenorhabditis elegans as testorganism. Sediments taken at various depths from three lakes of different trophic status and artificial sediments were spiked with sublethal concentrations of CuSO₄. After an exposure of 72 h to spiked sediment or liquid medium, body length of the nematodes was determined. Both artificial and natural sediments reduced the effect of copper, with natural sediments being more effective. In natural sediments worms grew normally at concentrations of copper up to 63.5 mg/L, whereas in artificial sediments body length was reduced at concentrations of 11.3 mg Cu/L or higher. Body length was positively correlated with content of fine particles and organic matter, indicating that particle size distribution and organic matter are determinant factors for the ecotoxicology of sediments.     

Identification of gonadal steroid receptors in meningiomas from dogs and cats

Cytosolic assay was used to detect gonadal steroid receptors in brain tumor tissue from 6 dogs and 2 cats. For 4 samples, the maximal number of binding sites and the equilibrium dissociation constant were calculated, using Scatchard analysis. The concentration of receptor protein that was discovered was similar to that detected in hormone-sensitive tumors.     

Anal leiomyoma in a Holstein heifer.

A 2-year-old heifer was presented with masses on her anus that were interfering with cervical manipulation during embryo flushing. The masses had broad stalks attached within the anal sphinchter. Recovery was without incident after surgical resection. No recurrence of the masses had occurred 3 months later. Histologic diagnosis was benign leiomyoma.     

Role of commercial aircraft in global monitoring systems

The role of commercial aircraft in monitoring meteorological parameters and atmospheric constituents has been limited in the former case and virtually nonexistent in the latter. I have tried to point out that this situation can and should be changed now. The new family of wide-bodied jets such as the 747, DC-10, and L-1011 aircraft can be used to supply important global atmospheric and tropical meteorological data for which there is a pressing need. While scientists are not in total agreement on the magnitude of the effect of particulates and gases on the atmosphere, there is almost unanimous concurrence that we are severely limited in information, and that global baseline concentrations must be established for particulates and gases in the troposphere and lower stratosphere as soon as possible. Also, more synoptic meteorological information from the tropical troposphere is highly desirable. In the final analysis, commercial aircraft may offer the most inexpensive way to monitor our atmosphere in the near future. Much of the instrumentation technology is here and the rest is certainly within our grasp. The fact of the matter is that there are now over 220 Boeing 747's and Douglas DC-10's in service, flying an average of 10 hours a day. Long-range flights, such as those from Tokyo to Anchorage to London in the Northern Hemisphere and from Hawaii to Pago Pago to Sydney in the Southern Hemisphere, are commonplace. These aircraft are equipped with inertial navigation systems and central air data computers coupled to advanced data storage systems which can readily be interrogated by satellite. This means that there is now a large amount of snyoptic weather information which can be obtained with a minimum of effort and cost. Likewise, a start at obtaining measurements of atmospheric constituents on a global basis can be made now. All we need to do is make the effort.     

Acquisition by innervated cardiac myocytes of a pertussis toxin-specific regulatory protein linked to the alpha 1-receptor

During development, the chronotropic response of rat ventricular myocardium to alpha 1-adrenergic stimulation changes from positive to negative. The alpha 1-agonist phenylephrine increases the rate of contraction of neonatal rat myocytes cultured alone but decreases the rate of contraction when the myocytes are cultured with functional sympathetic neurons. The developmental induction of the inhibitory myocardial response to alpha 1-adrenergic stimulation in intact ventricle and in cultured myocytes was shown to coincide with the functional acquisition of a substrate for pertussis toxin. A 41-kilodalton protein from myocytes cultured with sympathetic neurons and from adult rat myocardium showed, respectively, 2.2- and 16-fold increases in pertussis toxin-associated ADP-ribosylation (ADP, adenosine diphosphate) as compared to controls. In nerve-muscle cultures, inhibition of the actions of this protein by pertussis toxin-specific ADP-ribosylation reversed the mature inhibitory alpha 1-adrenergic response to an immature stimulatory pattern. The results suggest that innervation is associated with the appearance of a functional pertussis toxin substrate by which the alpha 1-adrenergic response becomes linked to a decrease in automaticity.     

Gammaglobulin factors (Gm and Inv) in New Guinea: anthropological significance

Analysis of the hereditary Gm and Inv gamma-globulin factors of 1669 New Guineans from the Morobe and Eastern Highlands districts and Bougainville Island demonstrates thatthe frequencies of the three Gm alleles present (Gm(a), GM(ab), and Gm(ax)) are similar in general to those in Mongoloids and in particular to those in Southeast Asians and Micronesians. The New Guinea frequencies are distinct from those in other populations, including Australian aborigines. Highly significant differences in frequencies of Gm and Inv alleles occur between Melanesian-and non-Austronesian-speaking New Guineans.     

Identification,pathogenicity and community dynamics of fungi and oomycetes associated with pea root rot in northern France

The pea root rot complex is a major concern for green pea production worldwide. This study aimed at characterizing its composition and dynamics throughout a cropping season in northern France. To this end, fungi and oomycetes were isolated from green pea plant roots with symptoms sampled at the flowering stage in 22 fields in 2017, and at the pea emergence, elongation and flowering stages in two fields in 2018. Out of 646 isolates collected, 317 were identified using molecular markers. Fusarium oxysporum, F. solani and F. redolens were highly predominant. Pathogenicity tests separated the isolates into four aggressiveness groups. F. solani isolates were the most aggressive. Phylogenetic analysis of their TEF1 sequences showed that they mainly belonged to the F. pisi lineage, and that F. oxysporum isolates were genetically close to isolates from the UK that did not belong to the forma specialis pisi. In addition, several Clonostachys rhizophaga isolates are reported for the first time to cause pea root rot. The oomycetes were rarely found and were represented by a few Pythium spp. isolates. Lastly, this study shows that the fungal and oomycete communities associated with pea root rot change during the cropping season. The level of dissimilarity of the root-rot-associated communities decreased throughout the cropping season towards a more similar composition at the flowering stage, dominated by F. solani, F. oxysporum and F. redolens. The proportion of nonpathogenic to weakly pathogenic isolates decreased progressively during the growing season in favour of moderately to highly pathogenic isolates.