The role of nucleoside-diphosphate kinase reactions in G protein activation of NADPH oxidase by guanine and adenine nucleotides

NADPH-oxidase-catalyzed superoxide (O2-) formation in membranes of HL-60 leukemic cells was activated by arachidonic acid in the presence of Mg2+ and HL-60 cytosol. The GTP analogues, guanosine 5'-[gamma-thio]triphosphate (GTP[gamma S] and guanosine 5'-[beta,gamma-imido]triphosphate, being potent activators of guanine-nucleotide-binding proteins (G proteins), stimulated O2- formation up to 3.5-fold. The adenine analogue of GTP[gamma S], adenosine 5'-[gamma-thio]triphosphate (ATP[gamma S]), which can serve as donor of thiophosphoryl groups in kinase-mediated reactions, stimulated O2- formation up to 2.5-fold, whereas the non-phosphorylating adenosine 5'-[beta,gamma-imido]triphosphate was inactive. The effect of ATP[gamma S] was half-maximal at a concentration of 2 microM, was observed in the absence of added GDP and occurred with a lag period two times longer than the one with GTP[gamma S]. HL-60 membranes exhibited nucleoside-diphosphate kinase activity, catalyzing the thiophosphorylation of GDP to GTP[gamma S] by ATP[gamma S]. GTP[gamma S] formation was half-maximal at a concentration of 3-4 microM ATP[gamma S] and was suppressed by removal of GDP by creatine kinase/creatine phosphate (CK/CP). The stimulatory effect of ATP[gamma S] on O2- formation was abolished by the nucleoside-diphosphate kinase inhibitor UDP. Mg2+ chelation with EDTA and removal of endogenous GDP by CK/CP abolished NADPH oxidase activation by ATP[gamma S] and considerably diminished stimulation by GTP[gamma S]. GTP[gamma S] also served as a thiophosphoryl group donor to GDP, with an even higher efficiency than ATP[gamma S]. Transthiophosphorylation of GDP to GTP[gamma S] was only partially inhibited by CK/CP. Our results suggest that NADPH oxidase is regulated by a G protein, which may be activated either by exchange of bound GDP by guanosine triphosphate or by thiophosphoryl group transfer to endogenous GDP by nucleoside-diphosphate kinase.     

Configuration and localization of the nipple-areola complex in men.

The causes of bilateral absence of the nipple-areola complex in men are seldom congenital, but attributable rather to destruction as a result of trauma, or after mastectomy in female-to-male transsexuals and in male breast cancer, or after the correction of extreme bilateral gynecomastia. Such a bilateral loss becomes a major reconstructive challenge with respect to the configuration and localization of a new nipple-areola complex. Because there is very little information available in the literature, we carried out a cross-sectional study on the configuration and localization of the nipple-areola complex in men.A total of 100 healthy men aged 20 to 36 years were examined under standardized conditions. The first part of the study dealt with the configuration of the nipple-areola complex (dimensions, round or oval shape). The second part concentrated on the localization of the complex on the thoracic wall with respect to anatomic landmarks and in correlation to various parameters such as weight and height of the body, circumference of the thorax, length of sternum, and position in the intercostal space.Of the 100 subjects examined, 91 had oval and seven had a round nipple-areola complex. An asymmetry between the right and the left side was found in two cases. The mean ratio of the horizontal/vertical diameter of an oval nipple-areola complex was 27:20 mm and the mean diameter for a round nipple-areola complex was 23 mm. The center of the nipple-areola complex was in the fourth intercostal space in 75 percent and in the fifth intercostal space in 23 percent of the subjects. To localize the nipple-areola complex on the thoracic wall de novo, at least two reproducible measurements proved to be necessary, composed of a horizontal line (distance from the midsternal line to the nipple = A) and a vertical line (distance from the sternal notch to the intersection of line A, = B). The closest correlation for the horizontal distance A was given by the circumference of the thorax: A = 2.4 cm + [0.09 x circumference of thorax (cm)], (r = 0.68). The best correlation to calculate the vertical distance B was found using the distance A and the length of the sternum: B = 1.2 cm + [0.28 x length of sternum (cm)] + [0.1 x circumference of thorax (cm)], (R = 0.50).In cases of bilateral absence, we recommend creating an oval nipple-areola complex in men. The appropriate localization can be calculated by means of two simple equations derived from the circumference of the thorax and the length of the sternum.     

Temperature-dependent reproduction of the spruce bark beetle Ips typographus,and analysis of the potential population growth

1. The spruce bark beetle Ips typographus (L.) is one of the most important forest pests in Central Europe, but despite this the effects of temperature on life history and population growth are largely unknown. This study examines the effects of temperature on reproduction and intrinsic demographic statistics. 2. Laboratory experiments on oviposition were carried out at six temperatures in the range 12–33 °C, using the so-called sandwich rearing technique for bark beetles. 3. A linear relationship between oviposition rates and temperatures in the range 15–25 °C was used to estimate the lower temperature threshold for oviposition as 11.4 °C. With a nonlinear model fitted to the data across the whole range of experimental temperatures, the lower and upper limiting temperatures and optimum temperature were found to be 7.9, 33.7, and 28.9 °C, respectively. A model for daily oviposition rate was fitted, which describes the pattern of oviposition over the entire oviposition period. 4. The analysis of life tables, combining developmental rates, reproduction, mortality, and sex ratio, suggests maximum population growth (r_m) at near 30 °C. 5. After generating a first brood, spruce bark beetles often re-emerge from the tree and produce other sister broods. The effects of temperature and number of sister broods on demography were evaluated using age-specific life-table analyses. It is hypothesized that sister broods play an important role in regions where I. typographus is monovoltine, but have only moderate significance where this species has more than one generation per season.     

How do host plant use and seasonal life cycle relate to insect body size: A case study on European geometrid moths (Lepidoptera: Geometridae)

We used European geometrid moths (>630 species) as a model group to investigate how life history traits linked to larval host plant use (i.e., diet breadth and host-plant growth form) and seasonal life cycle (i.e., voltinism, overwintering stage and caterpillar phenology) are related to adult body size in holometabolous insect herbivores. To do so, we applied phylogenetic comparative methods to account for shared evolutionary history among herbivore species. We further categorized larval diet breadth based on the phylogenetic structure of utilized host plant genera. Our results indicate that species associated with woody plants are, on average, larger than herb feeders and increase in size with increasing diet breadth. Obligatorily univoltine species are larger than multivoltine species, and attain larger sizes when their larvae occur exclusively in the early season. Furthermore, the adult body size is significantly smaller in species that overwinter in the pupal stage compared to those that overwinter as eggs or caterpillars. In summary, our results indicate that the ecological niche of holometabolous insect herbivores is strongly interrelated with body size at maturity.