CYP17 and CYP19 genetic variants are not associated with age at natural menopause in Polish women

The aim of the study was to investigate associations between two common polymorphisms of CYP17 and CYP19, encoding key enzymes of estrogen biosynthesis, and age at menopause in Polish women. One hundred fifty women after menopause (49.5 ± 3.8 years), with no previous history of hormone replacement therapy took part in the study. The genetic control group consisted of 150 newborns from the same population. We investigated an association between the age at menopause and the single nucleotide polymorphism T → C in the 5′ untranslated region (promoter) of the CYP17 gene (c.-34T>C; rs743572 – MspA1) or the number of tetranucleotide repeats [TTTA]_n (rs60271534) including deletion/insertion (D/I) of a 3 bp sequence in intron 4 of the CYP19 gene. CYP17 polymorphism was analyzed by PCR-RFLP and CYP19 by PCR and capillary electrophoresis. In the case of CYP17 polymorphism, 28.7% and 36.7% wild homozygous (TT), 50.7% and 46.0% heterozygous (TC), as well as 20.6% and 17.3% mutated homozygous (CC) types were identified in the subjects and controls, respectively. The frequency of mutated alleles (C) was 46.0% vs. 40.3% (p = 0.19). In the case of CYP19 polymorphism, 34.0% and 32.0% of homozygotes (1_1), 50.7% and 51.3% of heterozygotes (1_2), 15.3% and 16.7% of homozygotes (2_2) were identified in the subjects and controls, respectively. No association between the studied CYP17 or CYP19 polymorphisms and age at menopause was found in Polish women.     

The disturbance and vegetation dynamics: a review and an alternative framework

Disturbances are common phenomena that occurs in nature and significantly affects the dynamics of vegetation and plant populations. This paper shows that despite considerable progress in the theory of disturbances, for different authors the notion of disturbance has different meanings. The differences follow from an alternative understanding of the term, assumption of the holistic or reductionistic concept of the study or different approaches to equilibrium and non-equilibrium in nature. Different theoretical and methodological assumptions taken when analysing vegetation changes under the effect of disturbances allow relative arbitrariness in the interpretation of results. However, not all biotic interactions and ecological processes taking place in plant communities can be identified as disturbances. The effects of disturbances should be described on the basis of an objective assessment of what is normal for the functioning and stabilisation of a community as well as what disturbs and disrupts this equilibrium. Moreover, assuming the equivalent treatment of ecological systems, the interaction of the disturbing factors should be related to a specific level of life organisation (an individual, population or community), which would permit unambiguous discernment of the disturbance effects and finally generalise its effects on different levels of the hierarchical structure of vegetation.     

Microconchid tubeworms across the upper Frasnian – lower Famennian interval in the Central Devonian Field,Russia

Abstract: Microconchid tubeworms (Tentaculita) encrusting brachiopod shells have been investigated from the upper Frasnian – lower Famennian (Upper Devonian) deposits of the Central Devonian Field, Russia. The condition of microconchids and associated encrusting taxa is reported for the first time from the early Famennian recovery interval (crepida Chron) following the Frasnian–Famennian mass extinction. Two species, one new (Palaeoconchus variabilis sp. nov.) and the second one in open nomenclature (Palaeoconchus sp.), are described. Compared to lower Famennian specimens, they seem to be preferentially grouped on the anterior parts of the brachiopod host shells, which are interpreted as the most suitable sites away from the sea‐bottom and sediment. During the late Frasnian (Late rhenana Chron), microconchids, outnumbered by cornulitids and as abundant as foraminifers, were also associated with trepostome bryozoans, tabulates, rugose corals and various problematic encrusters. During the early Famennian recovery interval encompassing the crepida Chron, microconchids greatly outnumbered all associated encrusters, including the previously dominant cornulitids, while foraminifers, tabulates and rugose corals vanished. Early Famennian microconchids, represented by the single, albeit very abundant, species Palaeoconchus variabilis sp. nov., were opportunists that rapidly colonised the environment during the ongoing transgression following the regression‐driven biotic crisis in the area of the Central Devonian Field. In comparison to their late Frasnian predecessors and even other Middle Devonian specimens, no size reduction (the so‐called Lilliput effect) of early Famennian microconchid tubes was observed. It is probable that microconchids either rapidly attained their ‘normal’ sizes or they did not suffer any dwarfism following the Frasnian–Famennian event.     

By their own devices: invasive Argentine ants have shifted diet without clear aid from symbiotic microbes

The functions and compositions of symbiotic bacterial communities often correlate with host ecology. Yet cause–effect relationships and the order of symbiont vs. host change remain unclear in the face of ancient symbioses and conserved host ecology. Several groups of ants exemplify this challenge, as their low‐nitrogen diets and specialized symbioses appear conserved and ancient. To address whether nitrogen‐provisioning symbionts might be important in the early stages of ant trophic shifts, we studied bacteria from the Argentine ant, Linepithema humile – an invasive species that has transitioned towards greater consumption of sugar‐rich, nitrogen‐poor foods in parts of its introduced range. Bacteria were present at low densities in most L. humile workers, and among those yielding quality 16S rRNA amplicon sequencing data, we found just three symbionts to be common and dominant. Two, a Lactobacillus and an Acetobacteraceae species, were shared between native and introduced populations. The other, a Rickettsia, was found only in two introduced supercolonies. Across an eight‐year period of trophic reduction in one introduced population, we found no change in symbionts, arguing against a relationship between natural dietary change and microbiome composition. Overall, our findings thus argue against major changes in symbiotic bacteria in association with the invasion and trophic shift of L. humile. In addition, genome content from close relatives of the identified symbionts suggests that just one can synthesize most essential amino acids; this bacterium was only modestly abundant in introduced populations, providing little support for a major role of nitrogen‐provisioning symbioses in Argentine ant's dietary shift.     

Impact of plant cover on the cavity‐nesting ant Temnothorax crassispinus

1. Plant communities influence the availability of important resources for ants, such as nest sites and food, as well as environmental conditions. Thus, plants affect the abundance and distribution of ants. 2. In a field experiment, the influence of plant cover on the settlement of nest sites and per‐capita productivity of sexual individuals by the ant Temnothorax crassispinus was analysed. In July 2014, in five areas with patches of alien balsam Impatiens parviflora, and another five of native balsam I. noli‐tangere, transects composed of artificial nests were established; the nest sites were situated inside patches of balsams, and outside of them. Four hundred and forty artificial nests were used. One year later, the nests were collected. 3. Colonies of the ants three times more often inhabited nest sites outside the patches of both balsams. Besides, colonies with queens were more frequently found in nest sites located away from balsams. The per‐capita productivity of sexual individuals was higher in nests collected in patches of balsam, and the colonies from patches of alien balsam produced a more female‐biased sex ratio. 4. In terms of the impact on the ant, no clear differences were found between the alien balsam and the native one. The most important factor affecting the fitness of ants in areas dominated by balsams is the presence of herbaceous plant cover rather than whether the plant is alien or native.