Continuous growth through winter correlates with increased resting metabolic rate but does not affect daily energy budgets due to torpor use

Small mammals that are specialists in homeothermic thermoregulation reduce their self-maintenance costs of normothermy to survive the winter. By contrast, heterothermic ones that are considered generalists in thermoregulation can lower energy expenditure by entering torpor. It is well known that different species vary the use of their strategies to cope with harsh winters in temperate zones; however, little is still known about the intraspecific variation within populations and the associated external and internal factors. We hypothesized that yellow-necked mice Apodemus flavicollis decrease their resting metabolic rate (RMR) from autumn to winter, and then increase it during spring. However, since the alternative for seasonal reduction of RMR could be the development of heterothermy, we also considered the use of this strategy. We measured body mass (m_b), RMR, and body temperature (T_b) of mice during 2 consecutive years. In the 1st year, mice decreased whole animal RMR in winter, but did not do so in the 2nd year. All mice entered torpor during the 2nd winter, whereas only a few did so during the first one. Mice showed a continuous increase of m_b, which was steepest during the 2nd year. The relationship between RMR and m_b varied among seasons and years most likely due to different mouse development stages. The m_b gain at the individual level was correlated positively with RMR and heterothermy. This indicates that high metabolism in winter supports the growth of smaller animals, which use torpor as a compensatory mechanism. Isotope composition of mice hair suggests that in the 1st year they fed mainly on seeds, while in the 2nd, they likely consumed significant amounts of less digestible herbs. The study suggests that the use of specialist or generalist thermoregulatory strategies can differ with environmental variation and associated differences in developmental processes.     

Variation in sociosexuality across natural menstrual cycles: Associations with ovarian hormones and cycle phase

The psychological construct of sociosexuality—one's sexual openness or propensity to engage in uncommitted sexual relationships—has been broadly examined within numerous cultures and mating contexts. Although there is some evidence suggesting that components of sociosexuality, namely behavior, desire and attitude, change within-person, relatively little research has investigated potential sources of such variation. The aim of our study was to explore if the individual components of sociosexuality change across the menstrual cycle, either as a function of cycle phase or ovarian hormones. One hundred and two naturally cycling women, both single and in a committed relationships, completed questions from the the SOI-R (Sociosexuality Revised) questionnaire three times during a menstrual cycle, scheduled to coincide with their early follicular, peri-ovulatory, and luteal phases. Women provided saliva samples and performed luteinizing hormone tests to distinguish between ovulatory and anovulatory cycles. Women reported slightly more openness to uncommitted sexual relationships during the peri-ovulatory session, but significant differences were restricted only to women who exhibited the luteinizing hormone surge. Ovarian hormone concentrations within cycles significantly predicted SOI Attitude and Desire scores, with estradiol positively related, and progesterone negatively related to openness to uncommitted sexuality. These effects were generally modest in size. The results of this study suggest that sociosexuality can vary within short periods of time, such as a single menstrual cycle.     

PpEst is a novel PBAT degrading polyesterase identified by proteomic screening of Pseudomonas pseudoalcaligenes

A novel esterase, PpEst, that hydrolyses the co-aromatic-aliphatic polyester poly(1,4-butylene adipate-co-terephthalate) (PBAT) was identified by proteomic screening of the Pseudomonas pseudoalcaligenes secretome. PpEst was induced by the presence of PBAT in the growth media and had predicted arylesterase (EC 3.1.1.2) activity. PpEst showed polyesterase activity on both whole and milled PBAT film releasing terephthalic acid and 4-(4-hydroxybutoxycarbonyl)benzoic acid while end product inhibition by 4-(4-hydroxybutoxycarbonyl)benzoic acid was observed. Modelling of an aromatic polyester mimicking oligomer into the PpEst active site indicated that the binding pocket could be big enough to accommodate large polymers. This is the first report of a PBAT degrading enzyme being identified by proteomic screening and shows that this approach can contribute to the discovery of new polymer hydrolysing enzymes. Moreover, these results indicate that arylesterases could be an interesting enzyme class for identifications of polyesterases.

     

The Arabidopsis thaliana hypocotyl,a model to identify and study control mechanisms of cellular expansion

Developmental biology studies in general benefit from model organisms that are well characterized. Arabidopsis thaliana fulfills this criterion and represents one of the best experimental systems to study developmental processes in higher plants. Light is a crucial factor that drives photosynthesis, but that also regulates plant morphogenesis. As the hypocotyl is completely embryonic of origin, its growth occurs solely by expansion of the cells and this process is strongly dependent on the light conditions. In this review, we provide evidence that the hypocotyl serves as ideal model object to study cell expansion mechanisms and its regulation. We focus on the regulation of hypocotyl development by light and highlight the key modulating proteins in this signaling cascade. Downstream of light-signaling, cellular expansion is greatly dependent on specific cell wall depositions, which is related to cortical microtubular (re)arrangements and on composition and/or extensibility of the cell wall. We discuss possible further experimental approaches to broaden our knowledge on hypocotyl development, which will give an outlook on the probable evolution of the field.     

Screening of porous and cellular materials for covalent immobilisation of Agaricus bisporus tyrosinase

We conducted a systematic study of covalent immobilisation of Agaricus bisporus tyrosinase onto typical enzyme carriers. Acrylic beads, two commercial silica gels with different pore structures and mesoporous silica foam (MCFs) beads functionalised using different organosilanes showed that only aminated MCFs offer active preparations with immobilisation efficiencies greater than 100% and a similar ratio of diphenolase (L-DOPA) to monophenolase (L-tyrosine) activities as the free enzyme. The native enzyme was entirely inactivated during incubation at 55°C for 30 min, whereas the enzyme immobilised on acrylic carrier or MCF retained 46 and 35%, respectively, of the initial activity after similar treatment. Susceptibility of native and immobilised tyrosinase to suicide inactivation in the presence of L-tyrosine and L-DOPA was tested in repeated batch tests. However, none of the preparations obtained in the L-DOPA solution was operationally stable enough to be used for practical applications.     

Exposure to (1?→?3)-β-D-glucans in swine farms

The aim of this study was to assess the exposure to organic dust and (1 → 3)-β-D-glucans in the buildings where an intensive breeding of swine is going on and evaluation of the impact of the breeding technical conditions on the observed levels of bioaerosols. The study was carried out in 30 swine farms differentiated by the size of the herd and technical conditions of breeding. In 35 randomly selected buildings, air samples were collected by stationary measurements to determine the concentrations of organic dust and (1 → 3)-β-D-glucans in inhalable and respirable fractions. Furthermore, each of the investigated buildings was precisely characterized by means of a questionnaire for technical conditions and type of breeding. In each of the points, the microclimate parameters were measured, i.e., temperature, relative humidity, CO₂ concentration and air velocity. The analyzed levels of organic dust and (1 → 3)-β-D-glucans were characterized by a wide range of concentrations. For inhalable fraction, they reached respectively: organic dust (0.43–11.8 mg/m³), (1 → 3)-β-D-glucans (14–3,594 ng/m³). For respirable fraction, the results were as follows: organic dust (0.01–4.69 mg/m³), (1 → 3)-β-D-glucans (1–703 ng/m³). The concentrations of (1 → 3)-β-D-glucans were positively correlated with organic dust (r = 0.68; p < 0.001). The most significant factor increasing the concentrations of organic dust and (1 → 3)-β-D-glucans was the use of bedding in the form of cut straw. Additionally, the levels of (1 → 3)-β-D-glucans were affected by manual forage feeding, mechanical manure disposal and the lack of the liquid manure container in breeding buildings. In view of the hazardous effects of biological agents on the health of swine-breeding workers, the swine management systems without beddings should be used, along with automated dosing techniques.     

Probing the Monophyly of the Sphaeropleales (Chlorophyceae) Using Data From Five Genes

Molecular phylogenetic analyses have had a major impact on the classification of the green algal class Chlorophyceae, corroborating some previous evolutionary hypotheses, but primarily promoting new interpretations of morphological evolution. One set of morphological traits that feature prominently in green algal systematics is the absolute orientation of the flagellar apparatus in motile cells, which correlates strongly with taxonomic classes and orders. The order Sphaeropleales includes diverse green algae sharing the directly opposite (DO) flagellar apparatus orientation of their biflagellate motile cells. However, algae across sphaeroplealean families differ in specific components of the DO flagellar apparatus, and molecular phylogenetic studies often have failed to provide strong support for the monophyly of the order. To test the monophyly of Sphaeropleales and of taxa with the DO flagellar apparatus, we conducted a molecular phylogenetic study of 16 accessions representing all known families and diverse affiliated lineages within the order, with data from four plastid genes (psaA, psaB, psbC, rbcL) and one nuclear ribosomal gene (18S). Although single‐gene analyses varied in topology and support values, analysis of combined data strongly supported a monophyletic Sphaeropleales. Our results also corroborated previous phylogenetic hypotheses that were based on chloroplast genome data from relatively few taxa. Specifically, our data resolved Volvocales, algae possessing predominantly biflagellate motile cells with clockwise (CW) flagellar orientation, as the monophyletic sister lineage to Sphaeropleales, and an alliance of Chaetopeltidales, Chaetophorales, and Oedogoniales, orders having multiflagellate motile cells with distinct flagellar orientations involving the DO and CW forms.     

Diversity of Fusarium Species Isolated from Weeds and Plant Debris in Croatia

Weeds are alternative hosts of plant pathogens and when colonized may not exhibit disease symptoms. In 2008 and 2009, samples of weeds and plant debris were collected from 12 locations in eastern Croatia, and 300 Fusarium isolates colonizing them were identified. Strains were grouped and identified based on morphology and amplified fragment length polymorphism (AFLP) patterns. Portions of the β‐tubulin and translocation elongation factor 1‐α genes were sequenced from representative strains of each group to confirm the identifications. Fourteen Fusarium species were identified with F. graminearum (20%), F. verticillioides (18%), F. oxysporum (16%), F. subglutinans (13%) and F. proliferatum (11%) all present as more than 10% of the population. Fusarium acuminatum, F. avenaceum, F. concolor, F. crookwellense (F. cerealis), F. equiseti, F. semitectum, F. solani, F. sporotrichioides and F. venenatum, were all present at frequencies < 8%. Our results indicate that economically important Fusarium spp. may be isolated from numerous alternative hosts during the off season and that weeds and plant debris can serve as a reservoir of genetically diverse inoculum.     

The effect of adipokinetic hormones on the activity of digestive enzymes

The role of the adipokinetic hormone (AKH) in the control of protease, amylase and lipase activities is examined using the cockroach Periplaneta americana and the fruit fly Drosophila melanogaster as model species. The effects of Peram‐CAH‐I and ‐II on the activity of cockroach digestive enzymes in the gastric caeca and midgut are measured both in vivo and in vitro. The results show the activity of proteases, amylases and lipases in both parts of the gut: amylase activity is higher in the gastric caeca than in the midgut; lipase activity presents the opposite trend; and protease activity is similar in both organs. The applied hormones stimulate the activity of all digestive enzymes, although this stimulation is not uniform; AKHs affect enzymes selectively, and in some cases unequally, in the gastric caeca and midgut. No substantial differences between Peram‐CAH‐I and ‐II stimulation are recorded. The in vitro results demonstrate that AKH stimulates digestive enzyme activity directly. In agreement with the cockroach results, enzymatic activity in D. melanogaster larvae producing nonfunctional AKH is lower than that in the larvae with ectopically expressed Akh gene, where enzyme activity reaches or even exceeds that of the controls. Overall, the results demonstrate the active role of AKHs in the stimulation of digestive enzyme activity in insects.