Effect of landscape structure on the spatial distribution of Mediterranean dung beetle diversity

Aim  Landscape structure influences the distribution of animals, altering their movements and their ability to reach habitat patches. We analysed the spatial patterns of dung beetle species diversity in three differently structured natural landscapes in a Mediterranean protected area in the centre of the Iberian Peninsula.
Location  Cabañeros National Park, Central Spain.
Methods  Diversity components within (α) and among (β) the three main vegetation types in the reserve were compared by using a hierarchical nested design. These were forests, scrublands and grasslands embedded in three different landscapes, where each was the most dominant and structurally connected habitat.
Results  Species richness of grassland habitat did not vary across landscapes, but forest habitat showed lower species richness in the grassland-dominated landscape. Scrubland was the least species-rich habitat, but here again there was no significant variation across landscapes. However, in all cases, there was a significant influence of habitat context (configuration of habitat patches within landscape matrix) on similarity of species composition. These tended to be more similar to the dominant landscape matrix where they were embedded, rather than to the same habitat type in other landscapes. Additive partitioning of diversity showed higher than expected values of β in all landscapes, which indicated a structured response. Highest values of β in the grassland-dominated landscape suggest that this was the least connected landscape for dung beetles.
Main conclusions  Our results suggest that in homogeneous conditions of climate and trophic resources, landscape structure may well be more important than habitat type as a determinant of dung beetle distribution in the Mediterranean.     

NH2-terminal sequence of the isolated yeast ATP synthase subunit 6 reveals post-translational cleavage

The three mitochondrially translated ATP synthase subunits of Saccharomyces cerevisiae were extracted from the enzyme and from whole mitochondria using an organic solvent mixture and then purified by reverse-phase HPLC. The amino acid composition of subunit 6 is close to the one predicted from the oli2 gene. The partial amino terminal sequence of subunit 6 reveals a post-translational cleavage site between the Thr-10 and Ser-11 residues of the precursor. Thus, mature subunit 6 contains 249 amino acid residues and displays a molecular mass of 27943 Da.     

Immunocytochemical characterization of mouse monoclonal ACTH antibodies with a note on staining conditions and control procedures

Mouse monoclonal antibodies (MAbs) have been produced against porcine ACTH and tested for their immunocytochemical utility. Ten out of 12 MAbs reacted with formaldehyde-fixed human ACTH[1-39] and fragments thereof. Cytochemical fragment testing revealed that 6 of the 10 MAbs recognized epitopes in the vicinity of the region where porcine ACTH differs from mouse ACTH (amino acids 26, 29 and 31). Both tissue and cytochemical model data indicate that many of the MAbs detected porcine ACTH with somewhat higher potency than human and rat ACTH (rat ACTH[1-39] is identical to mouse ACTH[1-39]). MAbs Nos. 5, 8 and 12, in particular, revealed a highly satisfactory signal to noise ratio also in formalin-fixed, paraffin-embedded specimens. Most of the MAbs were potent in detecting both the high concentrations of ACTH congeners in corticotrophs and melanotrophs and the lower concentrations of such peptides in human antropyloric gastrin cells. Blocking of tissue endogenous peroxidase activity reduced reactivity towards the MAbs. This could be circumvented by use of biotinylated primary antibodies combined with avidin/streptavidin-alkaline phosphatase detection. Availability of MAbs and of the corresponding synthetic antigen also made some quantitative comparisons and analyses of appropriate control procedures possible.     

OPERATIVE AND POSTOPERATIVE EMERGENCY USE OF HYDROCORTISONE DERIVATIVES AND CORTICOTROPIN

Impairment of adrenal function is a great hazard to patients undergoing major operation. The most important adrenal steroids are glucocorticoids (hydrocortisone), 17-ketosteroids, mineralo-corticoids (aldosterone), and small amounts of estrogen and progesterone. Urinary output of 17-hydroxycorticoids reflects overall adrenal cortical activity. Under severe stress this output increases greatly.Adrenal replacement therapy is facilitated by the advent of more powerful and more soluble adrenal hormone derivatives. Hydrocortisone hemisuccinate sodium is the agent of choice in surgical emergencies and for management of bilateral adrenalectomy. Fatal adrenal crisis may develop during operation in patients receiving hydrocortisone for long periods of time. Hydrocortisone may be of help in unresponsive shock not due to loss of blood. The usual side effects of the corticoids can be controlled easily.     

Resolution of mitochondrial NADH dehydrogenase and isolation of two iron-sulfur proteins

The low molecular weight NADH dehydrogenase which can be solubilized from the mitochondrial NADH-ubiquinone oxidoreductase complex with chaotropic agents consists of three subunits in equimolar ratio [Galante, Y. M., & Hatefi, Y. (1979) Arch. Biochem. Biophys. 192, 559]. The largest subunit (subunit I) can be completely separated from the other two (subunits II + III) by treatment with sodium trichloroacetate and ammonium sulfate fractionation. Both the subunit I and subunit II + III fractions contain iron and acid-labile sulfur. From visible and EPR spectroscopy and the iron and acid-labile sulfide content, we propose that the subunit II + III fraction contains a binuclear cluster. The cluster structure present in subunit I is as yet unclear. On separation of the subunits of NADH dehydrogenase, the FMN is lost.     

Intratumour amount of sex steroids in elderly breast cancer patients. An approach to the biological characterization of mammary tumours in the elderly

Interest in breast cancer in elderly women is growing as a result of the high frequency of cancer in older age groups. We measured tumour concentrations and circulating levels of testosterone, dihydrotestosterone (DHT) and oestradiol in 50 postmenopausal patients: 26 younger than 70 yr (median, 61.5, range 50–69) and 24 older than 70 yr (median, 74.5, range 70–82). Hormones were measured by radioimmunoassay (RIA) after extraction and separation on celite column chromatography. Intratumour levels of the three steroids were lower in the older than in the younger patients, but the difference was statistically significant only for DHT (P = 0.0126). The decrease in the tumour concentrations of testosterone and DHT in the older group was associated with a slight increase in circulating levels, yielding as final result a statistically significant decrease of the tissue/plasma (T/P) ratio of these hormones. No significant difference was observed between groups for oestradiol levels. The blood levels of testosterone, DHT and oestradiol were significantly correlated in the older group, but not in the younger group. In contrast, the tumour amounts of testosterone and DHT were found to be significantly associated only in the < 70 yr group. We concluded that the hormonal environment in which breast cancer develops is different in younger and older postmenopausal patients, and that the difference mainly concerns the intratumour amounts of androgens, suggesting that the steroids concur in the growth regulation of mammary tumours.