Patterns of nucleolar activity during spermatogenesis of two triatomines, Panstrongylus megistus and P-herreri

The present work analyzed spermatogenesis in two species of triatomines (genus Panstrongylus) using silver-ion impregnation. The sex chromosomes of P. megistus and P. herreri had nucleolar organizing activity and became strongly impregnated during the phases of meiotic prophase I. Fragmentation of the nucleolus occurred in both species during the meiotic cycle. The nucleolar region could be observed up to diakinesis in meiotic prophase after which only nucleolar bodies and fragments were seen. Postmeiotic reactivation of rRNA synthesis occurred in these two species and was probably related to cell differentiation.

Patterns of nucleolar activity during spermatogenesis of two triatomines, Panstrongylus megistus and P. herreri

The present work analyzed spermatogenesis in two species of triatomines (genus Panstrongylus) using silver-ion impregnation. The sex chromosomes of P. megistus and P. herreri had nucleolar organizing activity and became strongly impregnated during the phases of meiotic prophase I. Fragmentation of the nucleolus occurred in both species during the meiotic cycle. The nucleolar region could be observed up to diakinesis in meiotic prophase after which only nucleolar bodies and fragments were seen. Postmeiotic reactivation of rRNA synthesis occurred in these two species and was probably related to cell differentiation.

Foraging activity and demographic patterns of two termite species (Isoptera: Rhinotermitidae) living in urban landscapes in southeastern Brazil

Coptotermes gestroi and Heterotermes tenuis (Isoptera: Rbinotermitidae) are important pests in southeastern Brazil causing serious economic damage. In this study we determined the demographic patterns and foraging activity of these species using mark-release-recapture and the consumption of wooden stakes. Using both the weighted mean and Lincoln index methods, population estimates ranged from ≈ 0.57 to 1.99 million individuals for C. gestroi and from ≈ 0.20 to 1.37 million for H. tenuis. Territory size of the colonies ranged from 172.5 to 5235 m 2 for C. gestroi and from 16 to 40 m 2 for H. tenuis. Our results also indicate that foraging activity was dependent on the minimum temperature; however, the existence of a compensation strategy in the foraging activities may permit foragers to exploit food sources under different environmental conditions.

Patterns of functional enzyme activity in fungus farming ambrosia beetles

Introduction In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles (Curculionidae: Scolytinae and Platypodinae), wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow) and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i) 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii) four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. Results We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-β-1,3(4)-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-β-1,4-xylanase activity was exclusively detected in larvae. Conclusion Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily accessible hemicellulose components of the ray-parenchyma cells in the wood xylem. Furthermore, the detection of xylanolytic enzymes exclusively in larvae (which feed on fungus colonized wood) and not in adults (which feed only on fungi) indicates that only larvae (pre-) digest plant cell wall structures. This implies that in X. saxesenii and likely also in many other ambrosia beetles, adults and larvae do not compete for the same food within their nests - in contrast, larvae increase colony fitness by facilitating enzymatic wood degradation and fungus cultivation.

The phosphorylation state of the FIGQY tyrosine of neurofascin determines ankyrin-binding activity and patterns of cell segregation

Cell–cell recognition and patterning of cell contacts have a critical role in mediating reversible assembly of a variety of transcellular complexes in the nervous system. This study provides evidence for regulation of cell interactions through modulation of ankyrin binding to neurofascin, a member of the L1CAM family of nervous system cell adhesion molecules. The phosphorylation state of the conserved FIGQY tyrosine in the cytoplasmic domain of neurofascin regulates ankyrin binding and governs neurofascin-dependent cell aggregation as well as cell sorting when neurofascin is expressed in neuroblastoma cells. These findings suggest a general mechanism for the patterning of cell contact based on external signals that regulate tyrosine phosphorylation of L1CAM members and modulate their binding to ankyrin.

Proteinase inhibitors I and II from potatoes block UVB-induced AP-1 activity by regulating the AP-1 protein compositional patterns in JB6 cells

Proteinase inhibitor I (Inh I) and proteinase inhibitor II (Inh II) from potato tubers are effective proteinase inhibitors of chymotrypsin and trypsin. Inh I and Inh II were shown to suppress irradiation-induced transformation in mouse embryo fibroblasts suggesting that they possess anticarcinogenic characteristics. We have previously demonstrated that Inh I and Inh II could effectively block UV irradiation-induced activation of transcription activator protein 1 (AP-1) in mouse JB6 epidermal cells, which mechanistically may explain their anticarcinogenic actions. In the present study, we investigated the effects of Inh I and Inh II on the expression and composition pattern of the AP-1 complex following stimulation by UV B (UVB) irradiation in the JB6 model. We found that Inh I and Inh II specifically inhibited UVB-induced AP-1, but not NFκB, activity in JB6 cells. Both Inh I and Inh II up-regulated AP-1 constituent proteins, JunD and Fra-2, and suppressed c-Jun and c-Fos expression and composition in bound AP-1 in response to UVB stimulation. This regulation of the AP-1 protein compositional pattern in response to Inh I or Inh II may be critical for the inhibition of UVB-induced AP-1 activity by these agents found in potatoes.

Trends in federal transportation financial activity, fiscal years 1970-1979 : report number 3 : projections of federal transportation obligations, 1980-1989 (based on 1970-1979 historical patterns) /

"DOT-P-10-80-22"--Cover.

The earnings tests and work patterns in four nations : an analysis of why work activity among older men does not increase when the earnings test is removed or liberalized /

Prepared for Social Security Administration, Comparative Studies Staff, Office of International Policy; prepared under grant no. 98083, Department of Health and Human Services, Social Security Administration.

Early patterns of sexual activity: age cohort differences in Australia

Patterns of first sexual activity among Australians born between the 1940s and 1980s were analysed using data from a national telephone survey of 1784 adults (876 males; 908 females). Sixty-one percent of those randomly selected from the Australian electoral roll and contactable by telephone responded. Many trends, including earlier first intercourse - from 20 to 18 years (females) and 18.8 to 17.8 years (males) - were established with the 40-49 year cohort, whose sexual debut was in the late 1960s-70s. Significant age-cohort effects saw women in the contemporary (18-29 year) cohort draw level with males for age at first intercourse and first sex before age 16 and before leaving school. First intercourse contraceptive use climbed from 30% to 80'%. Condom use quadrupled to 70%. Australian age-cohort effects are remarkably consistent with those in similar western cultures: gender convergence in sexual experience and increasing avoidance of sexually transmitted disease and pregnancy. If such trends continue, positive long-term outcomes for health and social wellbeing should result.

Emerging adulthood and patterns of physical activity among young Australian women

The transition from adolescence to young adulthood is associated with a sharp decline in physical activity, particularly for women. This article explores the relations between physical activity status and change and status and change in four life domains: residential independence, employment status, relationship status, and motherhood. Two waves of survey data from a representative sample of 8,545 Australian women, aged 18-23 at Survey 1 and 22-27 at Survey 2, were analyzed. Cross-sectionally, physical inactivity was most strongly related to being a mother married, and not being in the labor force. Longitudinally, decreases in physical activity were most strongly associated with moving into a live-in relationship, with getting married, and with becoming a mother When considered in combination, women who were married with children and not employed outside the home were the most likely to be physically inactive. The data suggest that adoption of adult statuses, particularly traditional roles involving family relationships and motherhood, is associated with reductions in physical activity for these women, although it is possible that the effect is driven by socioeconomic factors associated with early transitions. The data suggest a need for interventions to promote continued physical activity among young women who cohabit or marry and among those not in the workforce, in addition to those supporting young mothers to be physically active.