Null model analyses of temporal patterns of bird assemblages and their foraging guilds revealed the predominance of positive and random associations

Patterns of species associations have been commonly used to infer interactions among species. If species positively co‐occur, they may form predominantly neutral assemblages, and such patterns suggest a relatively weak role for compensatory dynamics. The main objective of this study was to test this prediction on temporal samples of bird assemblages (n = 19, 10–57 years) by the presence/absence and quantitative null models on assemblage and guild levels. These null model outcomes were further analyzed to evaluate the effects of various data set characteristics on the outcomes of the null models. The analysis of two binary null models in combination with three association indices revealed 20% with significant aggregations, 61% with random associations, and only 19% with significant segregations (n = 95 simulations). The results of the quantitative null model simulations detected more none‐random associations: 61% aggregations, 6% random associations, and 33% segregations (n = 114 simulations). Similarly, quantitative analyses on guild levels showed 58% aggregations, 20% segregations, and 22% random associations (n = 450 simulations). Bayesian GLMs detected that the outcomes of the binary and quantitative null models applied to the assemblage analyses were significantly related to census plot size, whereas the outcomes of the quantitative analyses were also related to the mean population densities of species in the data matrices. In guild‐level analyses, only 9% of the GLMs showed a significant influence of matrix properties (plot size, matrix size, species richness, and mean species population densities) on the null model outcomes. The results did not show the prevalence of negative associations that would have supported compensatory dynamics. Instead, we assume that a similar response of the majority of species to climate‐driven and stochastic factors may be responsible for the revealed predominance of positive associations.     

Light from heat lamps affects sow behaviour and piglet salivary melatonin levels

The light environment regulates animal physiology and behaviour. As widely used supplementary heat sources in creep areas, the effect of visible light radiated by infrared heat lamps on pigs is worth investigating. To investigate the effects of light from heat lamps on the behaviour of sows and piglets and possible endocrine mechanisms, 24 primiparous sows were randomly assigned to three supplementary heat source treatments: (1) 250 W non-luminous ceramic heat lamps (CE, n = 8), (2) 175 W red heat lamps (RL, n = 8), and (3) 175 W transparent heat lamps (TL, n = 8). All heat lamps were turned off on Day 15 postpartum. Piglets were weighed on days 3 and 21 postpartum. The number and duration of suckling within 24 h were analysed via video recordings on days 4, 8, and 16 postpartum. Sow posture changes during the day and night were detected using the YOLOv4 target detection network model. One marked piglet from six litters randomly selected from each treatment was used for saliva collection. Saliva samples were collected at 0800, 1400, 2000, and 0200 (+1 d) on days 10 and 20 postpartum. The results showed that the mean postural change frequency of TL sows was higher than that of CE sows (P < 0.05), while that of RL sows was not different from that of CE and TL sows. However, the duration of the sows being in each posture was not affected by the treatment. The total suckling duration of TL piglets was significantly longer than that of CE piglets, but there was no significant difference in the performance of the piglets. The melatonin concentrations in the saliva of piglets at 10 and 20 days of age in the three treatments showed different diurnal rhythms, but there was no significant difference in the levels of melatonin in TL piglets between night and day. Differences in salivary cortisol levels only appeared between the CE and RL groups at 20 days of age. Based on the present results, the illuminance and spectrum of the transparent heat lamps were sufficient to stimulate sow activity and inhibit melatonin levels in piglets. However, the stimulating effect on suckling was not sufficient to significantly improve the performance of piglets. Exposure to red heat lamps, rather than ceramic lamps, resulted in the strongest circadian rhythm of salivary melatonin in piglets.     

Association of the leukemia inhibitory factor gene mutation and the antiphospholipid antibodies in the peripheral blood of infertile women

To characterize the impact of the potentially functional mutation--the G to A transition at the position 3400 of the leukemia inhibitory factor (LIF; a pluripotent cytokine that plays a central role in the control of the embryo implantation) gene that leads to the exchange of valine with methionine at codon 64 we evaluated the association of the LIF gene mutation and the levels of antiphospolipid antibodies (aPLs) in the peripheral blood of infertile women (the aPLs examination was part of our routine immunological test during the infertility check-up). Eight infertile mutation-positive women were diagnosed with idiopathic infertility (n=5) and endometriosis (n=3) and their levels of aPLs in serum were compared with 115 infertile women without any LIF gene mutation. Enzyme-linked immunosorbent assay was used for the detection of seven antiphospholipid antibodies; the results were statistically assessed by the Fisher's 2 by 2 exact test to evaluate the association of the LIF gene mutations and aPLs in serum of infertile patients. The presence of aPLs was significantly higher in our study group (100%) than in 30% of aPLs-positives in control infertile patients (p = 0.0035) which indicates that the aPLs are elevated in women with LIF gene mutations.     

Synthesis and utilization of reversible and irreversible light-activated nanovalves derived from the channel protein MscL

This protocol details the chemical modification of the mechanosensitive channel of large-conductance (MscL) channel protein into a light-activated nanovalve and its utilization for triggered delivery in synthetic liposomal vesicles. It is based on charge-induced activation of this otherwise mechanosensitive channel by covalent attachment to the protein of rationally designed synthetic functionalities. In the dark, these functionalities will be uncharged and the channel will stay closed, but UV illumination will cause their ionization and trigger channel activity. In the case of reversible activation, subsequent illumination with visible light will neutralize the charge, causing the channel to close. The protocol includes synthesis of light-responsive compounds, protein isolation and its chemical labeling, reconstitution of the protein into artificial membranes, its analysis at the single-molecule level and its application in liposomal delivery. The whole protocol takes 4 days. Unlike mutagenesis, this method allows the introduction of custom-designed functional groups.     

Subspace projection approaches to classification and visualization of neural network-level encoding patterns

Recent advances in large-scale ensemble recordings allow monitoring of activity patterns of several hundreds of neurons in freely behaving animals. The emergence of such high-dimensional datasets poses challenges for the identification and analysis of dynamical network patterns. While several types of multivariate statistical methods have been used for integrating responses from multiple neurons, their effectiveness in pattern classification and predictive power has not been compared in a direct and systematic manner. Here we systematically employed a series of projection methods, such as Multiple Discriminant Analysis (MDA), Principal Components Analysis (PCA) and Artificial Neural Networks (ANN), and compared them with non-projection multivariate statistical methods such as Multivariate Gaussian Distributions (MGD). Our analyses of hippocampal data recorded during episodic memory events and cortical data simulated during face perception or arm movements illustrate how low-dimensional encoding subspaces can reveal the existence of network-level ensemble representations. We show how the use of regularization methods can prevent these statistical methods from over-fitting of training data sets when the trial numbers are much smaller than the number of recorded units. Moreover, we investigated the extent to which the computations implemented by the projection methods reflect the underlying hierarchical properties of the neural populations. Based on their ability to extract the essential features for pattern classification, we conclude that the typical performance ranking of these methods on under-sampled neural data of large dimension is MDA>PCA>ANN>MGD.     

Restoring marble trout genes in the Soča River (Slovenia)

In Slovenia, the unique watershed naturally hosting the marble trout is the So?a River, called Isonzo in Italy. In 1993–1996 molecular data established the existence of extensive hybridization with stocked Atlantic domestic lineages which is a threat for this taxon and for the economy of the country established on the angling tourism. Different management actions have been developed for restoring marble genes since 1996: banning stocking of brown trout, revising fishing regulations for anglers and testing genetically brood stock in hatchery for stocking phenotypic and pure marble fry. This long fight against hybridization was genetically surveyed using allozymes, mitochondrial sequences and microsatellites according to the available technique at each period. Despite the irregularity of genotyping along nearly fifteen years after the new management started, it appears that the proportion of domestic lineage in the river dropped regularly of about 2% each year, a positive result for conservative management measures.

     

Effects of Quercetin against Doxorubicin-Induced Testicular Toxicity in Male Rats

Biology Bulletin - This study investigated the protective effects of quercetin (QUE) in doxorubicin (DOX)-induced testicular toxicity in rats. In the present study, testicular histomorphometry, the...     

Species diversity in Gymnogeophagus (Teleostei: Cichlidae) and comparative biogeography of cichlids in the Middle Paraná basin,an emerging hotspot of fish endemism

Hydrobiologia - We address the diversity of two species groups of the cichlid genus Gymnogeophagus in the Middle Paraná basin using molecular phylogeography and traditional morphological...