Phenotypes of SLC26A4 gene mutations: Pendred syndrome and hypoacusis with enlarged vestibular aqueduct

This paper presents the current views, regarding the pathomechanisms, which lead to the development of pathological symptoms in the enlargement of the vestibular aqueduct syndrome (EVAS) and the Pendred syndrome (PS). Associated phenotypes have been discussed and an attempt has been undertaken to correlate them with a corresponding genotype. Mutations of SLC26A4 gene are one of the factors, which are at the base of congenital hearing losses. Inherited hearing loss occurs in these cases either as an isolated phenomenon with anatomical anomalies of the labyrinth in the background (EVAS) or with endocrine disorders (PS). The official name of SLC26A4 gene is "solute carrier family 26, member 4". Pendrin, the product of its expression, transports iodine beyond thyroid follicular cells, where it is linked with thyroglobulin and, then, used in hormone synthesis. Abnormal expression of SLC26A4 gene results in disturbance of iodine organification. In the internal ear, pendrin transports bicarbonates to the endolymph, taking in this way an active part in pH control of the endolymph and providing proper functioning of KCNJ10 potassium channels and TRP5 calcium channels. Disorders of homeostasis in labyrinth fluids are responsible for abnormalities of its structure, such as enlargement of the vestibular aqueduct and of the endolymph sac. At present, the Human Gene Mutations database provides 124 recessive mutations of SLC26A4 gene. In EVAS and PS, two missense mutations are most frequently observed: L236P and T416P, as well as the mutation, regarding abnormal splicing process, i.e., IVS8+1G-A, in a total of 55% of the patients with recognised mutation of SLC26A4 gene; the remaining 45% of changes of this gene are unique mutations.     

Biological indicators in marine and coastal waters: a statistical and modelling analysis of the MARS campaign

We perform a statistical analysis of ecological data collected in the MARS project from marine environments of the Red and Mediterranean Seas in Israel, and the North Sea in Germany. In the study of fish parasite data, we examine the basic premise that the complex host lifecycles of heteroxenous (h) parasites make them more sensitive to pollution than monoxenous (m) parasites which have only one host. Unlike results from analyses of earlier survey data, we find that the pooled h/m index for a community is not a clear indicator of environmental stress as originally hypothesized. This is due to the relatively large seasonal variability at the sampling sites over the course of the 3-year survey. Other possible indicators for water pollution gradients are checked, including species richness, diversity and prevalence of parasite populations. A theoretical model of host-parasite population dynamics that makes the presence of ecological thresholds transparent is offered to help explain the abrupt transitions prominent in the distributions of parasites at different sites under different pollution loadings. Heavy metal and chlorinated hydrocarbon data collected from fish tissue samples and molluscs of the three seas are assessed as bioindicators for pollution monitoring. The xenobiotic loads and indices of defence system activity and tissue damage are shown to have great potential as monitoring bioindicators.     

Complementary predation on metamorphosing species promotes stability in predator–prey systems

Functionally redundant predation and functionally complementary predation are both widespread phenomena in nature. Functional complementary predation can be found, for example, when predators feed on different life stages of their prey, while functional redundant predation occurs when different predators feed on all life stages of a shared prey. Both phenomena are common in nature, and the extent of differential life-stage predation depends mostly on prey life history; complementary predation is expected to be more common on metamorphosing prey species, while redundant predation is thought to be higher on non-metamorphosing species. We used an ordinary differential equation model to explore the effect of varying degree of complementary and redundant predation on the dynamic properties of a system with two predators that feed on an age-structured prey. Our main finding was that predation on one stage (adult or juvenile) resulted in a more stable system (i.e., it is stable for a wider range of parameters) compared to when the two predators mix the two prey developmental stages in their diet. Our results demonstrate that predator–prey dynamics depends strongly on predators' functionality when predator species richness is fixed. Results also suggest that systems with metamorphosing prey are expected to be more diverse compared to systems with non-metamorphosing prey.     

Beyond “greening” and “browning”: Trends in grassland ground cover fractions across Eurasia that account for spatial and temporal autocorrelation

Grassland ecosystems cover up to 40% of the global land area and provide many ecosystem services directly supporting the livelihoods of over 1 billion people. Monitoring long-term changes in grasslands is crucial for food security, biodiversity conservation, achieving Land Degradation Neutrality goals, and modeling the global carbon budget. Although long-term grassland monitoring using remote sensing is extensive, it is typically based on a single vegetation index and does not account for temporal and spatial autocorrelation, which means that some trends are falsely identified while others are missed. Our goal was to analyze trends in grasslands in Eurasia, the largest continuous grassland ecosystems on Earth. To do so, we calculated Cumulative Endmember Fractions (annual sums of monthly ground cover fractions) derived from MODIS 2002–2020 time series, and applied a new statistical approach PARTS that explicitly accounts for temporal and spatial autocorrelation in trends. We examined trends in green vegetation, non-photosynthetic vegetation, and soil ground cover fractions considering their independent change trajectories and relations among fractions over time. We derived temporally uncorrelated pixel-based trend maps and statistically tested whether observed trends could be explained by elevation, land cover, SPEI3, climate, country, and their combinations, all while accounting for spatial autocorrelation. We found no statistical evidence for a decrease in vegetation cover in grasslands in Eurasia. Instead, there was a significant map-level increase in non-photosynthetic vegetation across the region and local increases in green vegetation with a concomitant decrease in soil fraction. Independent environmental variables affected trends significantly, but effects varied by region. Overall, our analyses show in a statistically robust manner that Eurasian grasslands have changed considerably over the past two decades. Our approach enhances remote sensing-based monitoring of trends in grasslands so that underlying processes can be discerned.     

Bin classification of G-protein-coupled peptide receptors

Summary With the use of the binmap method, 154 G-protein-coupled peptide receptors are classified. The binmap coordinates are obtained by using the number of residues between the conserved N residue in TM1 and C in the TM4-TM5 loop, between this C and the conserved P in TM6, and between this P and the last residue of the sequence. The binmap suggests that the cloned fMLP receptor in rabbit belongs in fact to the IL8 receptor type.     

Trade up polygyny and breeding synchrony in avian populations

The advent of the molecular techniques used to assign paternity has focused attention on the differences between the social and the genetic mating systems of sexual species. In particular, the interrelations between breeding synchrony-the degree to which the fertility periods of individual females in a population overlap and the degree of extra pair paternity (EPP) in that population, has became a subject of a lively debate. Investigation of the subject can be facilitated by examining the criteria that females use in choosing extra pair partners. These preferences constitute a continuum ranging between two extremes. At one end, there are situations wherein all the females in a population exhibit a preference for males with particular phenotypic markers, and females mated to males lacking such "quality" markers seek extra pair fertilizations from males that do -trade up polygyny. At the other extreme, there are situations wherein females seek to maximize the total number of male partners, rather than secure fertilization by males of particular type -indiscriminate polygyny. Previously, we used game theoretical methods to model the interrelations between breeding synchrony and EPP in the context of indiscriminate polygyny. Here we present an analogous investigation in the context of trade up polygyny. Our results for the two cases, which delimit the range of the possible behavior, are similar. That is, we see that it is the pursuit of extra pair fertilizations opportunities that determines breeding synchrony of populations, rather than the vice versa as has been previously suggested.