Effect of 2450 MHz microwave exposure on behavioural thermoregulation in mice

1. 1.|The purpose of this study was to determine the threshold specific absorption rate (SAR) during exposure to 2450 MHz continuous wave (CW) microwaves that affected thermoregulatory behaviour in mice.

2. 2.|A Plexiglas shuttle box was placed inside a waveguide imposed with a temperature gradient. The temperature gradient allowed the mice to select a particular section of the shuttle box which was, presumably, related to their state of thermal comfort. Exposing the mice to 2450 MHz inside the waveguide at SARs of 0–5.3 W kg⁻¹ for 1 h caused no significant change in their preferred ambient temperature.

3. 3.|Increasing SAR from 5.3 to 18.1 W kg⁻¹ caused the animals to shift their position to the cooler end of the shuttle box.

4. 4.|Following termination of microwave exposure animals that had selected a cool ambient temperature returned to the warm side of the shuttle box.

5. 5.|It is concluded that for mice exposed to radiation at 2450 MHz the thermoregulatory behaviour is significantly affected at SARs of 5.3 to 9.9 W kg⁻¹.

The acoustic repertoire of the Southern right whale,a quantitative analysis

Some 1274 southern right whale sounds were randomly selected and each sound was described by 10 acoustic variables. Two hundred and fifty of these sounds were also ‘labelled’ by the activity, size and sexual composition o the group producing them. Principal components analysis was performed on all the sounds' variables (1274×10) and on the variables for a subset of 823 sounds referred to as calls. Results of the principal components analyses indicate that the sounds can be divided into three major classes: blow sounds, slaps, and calls; and that the repertoire of calls is a continuum with certain types more common than others. The distribution of the ‘labelled’ sounds in the principal components analyses patterns revealed general associations between whale activities and the types of sounds produced.     

Histochemical analysis of rat testicular glycoconjugates. 1. Subsets of N-linked saccharides in seminiferous tubules

Summary The distribution of N-linked glycans in rat testis has been probed using a panel of lectins derived fromGalanthus nivalis (snowdrop, GNA),Canavalia ensiformis (jack bean, Con A),Lens culinaris (lentil, LCA),Pisum sativum (garden pea, PSA) andPhaseolus vulgaris, erythro- and leucoagglutinins (kidney bean, ePHA and IPHA). Several classes of N-linked glycan were identified in the spermatogenic series, and during differentiation into spermatozoa they altered in both their pattern of distribution and relative abundance. A population of tetra-antennary, non-bisected, complex glycans, detected by IPHA, was lost during the transition from spermatogonia to spermatocytes, while high-mannose structures were acquired; these were most abundant in spermatocytes, as were bi- and tri-antennary complex, non-bisected glycans, the latter becoming increasingly abundant on acrosomes and spermatozoa. Their bisected counterparts were more generally expressed throughout spermatogenic cells, although marked localization onto acrosomes and nuclear caps was again seen. Transition from spermatocytes to spermatids involved mainly changes of the acrosomal granule and nuclear cap, which were carried through to the final stages of differentiation. Sertoli cell surfaces and cytoplasmic granules showed a high level of N-glycan expression.     

Histochemical analysis of rat testicular glycoconjugates. 2. Beta-galactosyl residues in O- and N-linked glycans in seminiferous tubules.

Summary Rat testes have been examined with a panel of lectins that bind specifically to oligosaccharide sequences having terminal or subterminal -galactosyl residues in O-linked glycans, or in the outer chains of complex N-linked glycans:Arachis hypogaea (peanut, AHA),Erythrina cristagalli (coral tree, ECA),Ricinus communis (castor bean, RCA120) andAbrus precatorius (jequirity bean, APA) agglutinins. Pretreatment of sections with neuraminidase, -galactosidase and removal of alkali-labile O-linked sequences by -elimination allowed the structure of these glycans to be further explored. In spermatogonia and spermatocytes there was little evidence of glycans terminating in -galactosyl residues, although these were present at non-reducing terminals as sialylgalactosides. The acrosome contained two subsets of O-linked glycans terminating in sialylgalactosides, while the nuclear cap showed at least two subsets of N-linked sialylgalactosyl as well as O-linked glycans. Spermatozoa exhibited minor changes in the pattern of glycosylation, although the overall pattern of -galactosyl expression was similar. Binding to Sertoli cells showed the presence of some unsubstituted -galactosyl terminals on O-linked glycans but few such N-linked residues, while terminal -galactosides were scanty in tubular basement membranes.     

Biogeographic comparisons of marine algal polyphenolics: evidence against a latitudinal trend

Summary Marine allelochemicals generally are present in greater quantity and diversity in tropical than in temperate regions. Marine algal polyphenolics have been reported as an apparent exception to this biogeographic trend, with literature values for phenolic concentrations significantly higher in temperate than in tropical brown algae. In contrast, our results, the first reported for Caribbean brown algae (orders Dictyotales and Fucales), show that many species have high phenolic levels. In addition, both our study and previous studies with north temperate and tropical species demonstrate that there is marked variation in algal phenolic levels within species from different locations. We conclude that high phenolic concentrations occur in species from both temperate and tropical regions, indicating that latitude alone is not a reasonable predictor of plant phenolic concentrations.     

Anhydrobiosis in Nematodes II: Carbohydrate and Lipid Analysis in Undesiccated and Desiccate Nematodes

Glycogen, trehalose, glucose, and total lipid contents of six nematode species were studied. Anhydrobiotic Anguina tritici and Ditylencbus dipsaci stored trehalose in preference to glycogen and only small amounts of glucose were detected. Glycogen content was also reduced in anhydrobiotic Aphelenchus avenae. Conversely, Panagrellus redivivus and Turbatrix aceti contained large amounts of glycogen, appreciable amounts of glucose, and minimal amounts of trehalose. Ditylenchus myceliophagous "curds" contained low amounts of glycogen and very little trehalose; total lipid was 60% of that in fresh samples. The lipid contents of fresh samples of P. redivivus, T. aceti, and A. avenae were high (23.1, 21.9, and 36.7% dry weight, respectively), but in anhydrobiotic A. avenae larvae the level was reduced by over 60%. In contrast, lipid levels remained high in anhydrobiotic A. tritici and D. dipsaci larvae (40.6 and 38.3%, respectively). Analysis of lipid composition in anhydrobiotic A. tritici and A. avenae did not indicate any specific metabolic adaptations to desiccation survival.     

Maturation of ribosomal precursor RNA in Saccharomyces cerevisiae: A mutant with a defect in both the transport and terminal processing of the 20 S species

A mutant (CLP-8) of Saccharomyces cerevisiae possesses an abnormal ratio of native ribosomal subunits since it has an apparent deficiency of cytoplasmic 40 S subparticles. The mutant also has an abnormal anti-association factor activity. The lesion(s) responsible for the ribosomal subunit inbalance is not temperature-sensitive and is incomplete since the mutant still grows, albeit at a reduced rate compared to that of its parent. The lesion(s) in CLP-8 is, however, expressed at the level of 20 S ribosomal precursor RNA maturation. Thus, relative to the wild-type strain, there is both a slowed transport of 20 S ribosomal precursor RNA from the nucleus to the cytoplasm and a slowed cytoplasmic conversion of this RNA component into the mature 18 S form.