Social influences on estrogen excretion and ovarian cyclicity in saddle back tamarins (Saguinus fuscicollis)

The effects of different social living conditions on estrogen excretion and on the ovarian cycle of saddle back tamarins were investigated. Urinary estrogens were monitored as indices of ovarian cyclicity in groups of adult females living under the following experimental conditions: (1) five parous females, each living with an adult castrated male (in one of the females plasma estradiol and progesterone were also measured); (2) five adult daughters living with their families. Each daughter was then removed from her family and paired with a vasectomized male. After pairing, scent marks collected from the family were introduced daily to one of the daughters and her mate. Scent exposure was then discontinued and hormone excretion measured for several weeks. The remaining four daughters were not exposed to family scent. The females living with castrated males showed urinary estrogen cycles of an average length of 17.5 ± 1.0 days. The plasma estrogen cycle was of the same length. The females studied under condition 2 showed low, noncycling estrogen levels while living in their families. They responded to pairing with an increase in the level of urinary estrogens, and four out of five showed regular estrogen cyclicity. The fifth female exposed to family scent marks after pairing also showed an increase in urinary estrogens. However, as long as scent transfer was maintained, no cycle was observed. Estrogen excretion increased again, and cyclicity commenced when scent transfer was discontinued. It is concluded that ovarian estrogen production is suppressed and cyclicity does not occur as long as daughters live in their families. Release from suppression and perhaps stimulation by the male cause a rapid increase in estrogen levels and the onset of cyclicity. Chemical stimuli produced by the family, perhaps particularly by the mother, may be involved in reproductive suppression.     

Die Beeinflussung der Histochemisch Nachweisbaren ATPase-Aktivität unter verschiedenen Versuchsbedingungen beim Vergleich der Ca- sowie Pb-Methode bei Ph 7,5 bzw. 7,2

Zusammenfassung Es wird über vergleichende Untersuchungen beim Nachweis der ATPase im niederen pH-Bereich unter Verwendung der Ca- und Pb-Methode berichtet. Hierbei zeigt es sich, daß es sich um ATPasen mit unterschiedlichen Eigenschaften handelt. Während die ATPase pH 7,2 keine Abhängigkeit von SH-Gruppen aufweist und Mg^.. benötigt, wird die Aktivität der ATPase pH 7,5 (Ca-Methode) durch SH-Gruppen-Blocker gehemmt, es tritt eine Aktivitätsminderung nach Zugabe von Mg^.. ins Inkubationsmedium ein. Auch der Einfluß der Fixierung ist bei beiden ATPasen unterschiedlich. Unabhängig hiervon ist hervorzuheben, daß sich auch Unterschiede im Verhalten der ATPase in Abhängigkeit vom untersuchten Organ ergeben. Unsere Ergebnisse unterstützen die Notwendigkeit eines spezifischen, von der Fragestellung bestimmten, Nachweises der ATPase.

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Summary The results of comparative studies on the determination of ATP-ase in the low pH range (using the Ca- and the Pb-method) are reported. The findings show that there are ATP-ases of different properties. Whereas ATP-ase pH 7.2 depends not on SH-groups but on the presence of Mg^.., the activity of ATP-ase pH 7.5 (Ca-method) is inhibited not only by SH-group blockers but also by the addition of Mg^.. to the incubation medium. There is also evidence that fixation has varying effects on ATP-ases. However, it must be emphasized that there are differences in the ATP-ase activity within the various organs investigated. Our results show that the choice of the method for a specific demonstration of ATP-ase depends to a very high degree on the problem under investigation.

     

Environmental heterogeneity determines the ecological processes that govern bacterial metacommunity assembly in a floodplain river system

How diversity is structured has been a central goal of microbial ecology. In freshwater ecosystems, selection has been found to be the main driver shaping bacterial communities. However, its relative importance compared with other processes (dispersal, drift, diversification) may depend on spatial heterogeneity and the dispersal rates within a metacommunity. Still, a decrease in the role of selection is expected with increasing dispersal homogenization. Here, we investigate the main ecological processes modulating bacterial assembly in contrasting scenarios of environmental heterogeneity. We carried out a spatiotemporal survey in the floodplain system of the Paraná River. The bacterioplankton metacommunity was studied using both statistical inferences based on phylogenetic and taxa turnover as well as co-occurrence networks. We found that selection was the main process determining community assembly even at both extremes of environmental heterogeneity and homogeneity, challenging the general view that the strength of selection is weakened due to dispersal homogenization. The ecological processes acting on the community also determined the connectedness of bacterial networks associations. Heterogeneous selection promoted more interconnected networks increasing β-diversity. Finally, spatiotemporal heterogeneity was an important factor determining the number and identity of the most highly connected taxa in the system. Integrating all these empirical evidences, we propose a new conceptual model that elucidates how the environmental heterogeneity determines the action of the ecological processes shaping the bacterial metacommunity.Subject terms: Community ecology, Microbial ecology     

Identification of Medieval Human Soft Tissue Remains in an Advanced State of Decomposition

Naturally preserved human soft tissue remains from mediaeval burials (ll-13th century A. D.) were investigated histologically after azocarmine/aniline alcohol (AZAN) or keratin-prekeratin-mucin (KPM) staining. The tissue remnants were in an advanced state of decomposition; they were completely collapsed and had lost their macroscopic characteristics. After rehydration, thin sectioning, and staining, microscopic properties permitted tissue identification, although differential staining of tissue components did not necessarily correspond with the expected results based on fresh tissue. The techniques and results presented in this paper are relevant for both anthropological and forensic purposes.     

Mycorrhizal response of <Emphasis Type="Italic">Clusia pusilla</Emphasis> growing in two different soils in the field

Arbuscular mycorrhizas (AM) are important for promoting the mineral nutrition, growth and survival of plants used to rehabilitate degraded areas. Clusia pusilla is an evergreen shrub which is tolerant of high irradiance, germinates readily and can be easily reproduced by cuttings. All these characteristics make this species useful in the recovery of deforested areas. The aim of this work was to explore the response of C. pusilla to AM in the field, in two types of soil: the shrubland soil in which the species naturally grows and in a soil of a riparian forest. Eight treatments were performed in each type of soil. The treatments consisted of a non-mycorrhizal control and mycorrhizal plants colonized by one of the three AM inocula tested in the presence or absence of triple superphosphate (150 kg ha^-1). After 11 months of growth in the shrubland soil, C. pusilla seedlings showed an increase in height and dry weight in response to the fertilizer but not to mycorrhizas. In contrast, in the forest soil the arbuscular mycorrhizal fungi (AMF) effect was equivalent to the fertilizer effect, and the two effects interacted positively. The lack of response to AM in shrubland soil was caused by its high sand content, which hinders the retention of the inocula. Due to a higher clay content, the forest soil binds inocula more tightly than shrubland soil. In conclusion, C. pusilla appears to benefit greatly from the addition of AMF in forest soil, though it requires an additional P source for such benefits in shrubland soil. This P source must be organic so that phosphorus is not lost by leaching. Although the growth rate of this species is very low, its survival can be guaranteed with the application of AMF inocula together with P-fertilizer applied at a low rate.     

Glutathione S transferase mu polymorphism and gastric cancer in the Portuguese population

The glutathione S-transferases appear to form part of a protective mechanism against the development of cancer where environmental chemical carcinogens are involved. In humans one member of the mu class gene family (GSTM1) has been shown to be polymorphic and is only expressed in ~50% of individuals. Previous studies have shown a possible link between the null phenotype and susceptibility to cancer but have been equivocal regarding stomach cancer. To evaluate any association in Portuguese gastric cancer individuals with GSTM1 variability, we performed GST M 1 polymorphism by PCR amplification in 148 gastric cancer patients and in 84 healthy control individuals. We found no statistical differences between the gastric cancer and control populations (wild type phenotype: 52%, 48%; null phenotype: 48%, 52%, respectively). A subset analysis into site of tumour also revealed no significant differences between the groups, although we found a slight increase of the wild type phenotype in the samples of the antrum compared with the control population (57% vs 48%, respectively; 2= 1.18; p 0.28) and a slight increase of the null phenotype in the signet ring cells/mucocellular group ( 2= 1.05; p 0.3). However, in both cases it did not reach statistical significance. A subset analysis of the histological groups following the WHO criteria revealed a statistically significant difference ( 2= 3.704; p 0.05) between the moderately differentiated gastric adenocarcinoma and the presence of the wild type phenotype. These results do not support the hypothesis that the GSTM1 null phenotype predisposes to gastric cancer in the Portuguese population and the moderately differentiated gastric adenocarcinoma seems to be associated with the presence of the G STM 1 wild type phenotype.