Parental effects in Pieris rapae in response to variation in food quality: adaptive plasticity across generations?

1. Herbivores using seasonal resources must cope with variation in the quality of their host plants. The effects of variation in protein concentration of artificial diet and glucosinolate concentration in canola, Brassica napus, on Pieris rapae parental and progeny growth were investigated. 2. The hypothesis that parents respond to variation in food quality by altering the phenotype of their progeny to enhance progeny fitness was tested. Consistent with previous studies, P. rapae was not affected strongly by variation in the protein concentration of artificial diet and had equal mass on completing development. 3. The mass of individual eggs of P. rapae progeny was correlated negatively with the amount of protein in the diet on which parents fed. Moreover, mothers reared in extreme conditions (high and low protein) produced progeny that grew best under those conditions. These potentially adaptive parental effects were detected early in progeny growth but not later in their development. 4. Early larval growth of P. rapae was affected negatively by increasing glucosinolates in B. napus plants, although no effects of glucosinolates were detected later in growth or on the progeny's phenotype. 5. Thus, evidence is presented that variation in food quality (protein concentration) has major consequences for the progeny of P. rapae. Given the multivoltine life history of P. rapae and the seasonal differences in food quality it encounters, such parental effects may be adaptive.     

Is KCl a reliable extractant of15NH 4 + added to coastal marine sediments?

The release of NH ₄ ⁺ and¹⁵N-labelled NH ₄ ⁺ by one-step KCl extraction was assessed in different types of coastal marine sediments. KCl was efficient to extract NH ₄ ⁺ from sandy sediments and less efficient in silt sediments, where an extended extraction period was required for obtaining a maximum NH ₄ ⁺ yield. Extraction at 0 or 20 °C had only a little effect on the efficiency of KCl. KCl gave always non complete recovery of¹⁵NH ₄ ⁺ in silt sediments. However, the added label could be fully recovered by addition of 80 mol·cm^–3 exogenous NH ₄ ⁺ prior to KCl, or when NaCl or ASW replaced KCl.¹⁵NH ₄ ⁺ was added to non-biological silt sediment, which was incubated at 0 °C up to 16 hours, to see the effect of physical processes on the partition of¹⁵NH₄ among porewater (29–49%) exchangeable (9–30%) and non-extractable, organic bound pools (24–42%). Total¹⁵N recovery was approximately 100%. KCl failed to remove¹⁵NH₄ which entered to unknown, bound pools in sediment. Only shortly after addition of¹⁵N (0.1 h), the extraction period resulted in significantly different¹⁵N recoveries (P < 0.05) in KCl extractable NH ₄ ⁺ , 17% versus 9% of label was recovered after 1 min or 60 min extraction of sediment, respectively. Two hours of incubation time were required for complete equilibrium of¹⁵NH ₄ ⁺ among porewater, exchangeable and organic bound pools. Sediments (silt) to which¹⁵NH ₄ ⁺ has been added in order to measure NH ₄ ⁺ turn-over and KCl is used as extractant, should be incubated for at least 2 hours, before taking a zero-time sample.     

Changes in size of Baltic field voles over the last 50 years: are they really shrinking?

Using museum materials and recently trapped specimens of field voles (Microtus agrestis (Linnaeus, 1761)) from Lithuania and Estonia, we assessed temporal and latitudinal trends in body and skull size, comparing the periods 1980–1996 and 2014–2016. We measured four body and 23 skull characters, size-adjusting them using the geometric mean procedure. A pronounced decrease in the size of M. agrestis was noted in Estonia, where 23 out of 27 adjusted body and skull characters had decreased by up to 21.9%, with only the tail length, hind foot length, maximum height of mandibula excluding coronoid process and coronoid height of mandibula increasing significantly. Decreases were less marked in voles from Lithuania – most pronounced were a 6.1% decrease in adjusted body length, an 11.6% decrease in adjusted length of the braincase, a 3.85% decrease in the breadth of the braincase, measured at the widest part, a 2.9% decrease in condylobasal skull length and a 2.2% decrease in the height of the braincase. The coronoid height of the mandibula of Lithuanian individuals showed an 8.4% size increase. In both countries, the confounding effect of sex on the size changes of M. agrestis from 1980 to 2016 was much smaller than the effect of time period. Concluding, voles in Estonia became significantly smaller, while changes in the measured characters in Lithuania were heterogeneous.     

Regulation of phosphoinositide signaling by the inositol polyphosphate 5-phosphatases

Phosphoinositide signaling molecules control cellular growth, proliferation and differentiation, intracellular vesicle trafficking, and cytoskeletal rearrangement. The inositol polyphosphate 5-phosphatase family remove the D-5 position phosphate from PtdIns(3,4,5)P3, PtdIns(4,5)P2 and PtdIns(3,5)P2 forming PtdIns(3,4)P2, PtdIns(4)P and PtdIns(3)P respectively. This enzyme family, comprising ten mammalian members, exhibit seemingly non-redundant functions including the regulation of synaptic vesicle recycling, hematopoietic cell function and insulin signaling. Here we highlight recently established insights into the functions of two well characterized 5-phosphatases OCRL and SHIP2, which have been the subject of extensive functional studies, and the characterization of recently identified members, SKIP and PIPP, in order to highlight the diverse and complex functions of this enzyme family.     

Gap junction channels exhibit connexin-specific permeability to cyclic nucleotides

Gap junction channels exhibit connexin dependent biophysical properties, including selective intercellular passage of larger solutes, such as second messengers and siRNA. Here, we report the determination of cyclic nucleotide (cAMP) permeability through gap junction channels composed of Cx43, Cx40, or Cx26 using simultaneous measurements of junctional conductance and intercellular transfer of cAMP. For cAMP detection the recipient cells were transfected with a reporter gene, the cyclic nucleotide-modulated channel from sea urchin sperm (SpIH). cAMP was introduced via patch pipette into the cell of the pair that did not express SpIH. SpIH-derived currents (I(h)) were recorded from the other cell of a pair that expressed SpIH. cAMP diffusion through gap junction channels to the neighboring SpIH-transfected cell resulted in a five to sixfold increase in I(h) current over time. Cyclic AMP transfer was observed for homotypic Cx43 channels over a wide range of conductances. However, homotypic Cx40 and homotypic Cx26 exhibited reduced cAMP permeability in comparison to Cx43. The cAMP/K(+) permeability ratios were 0.18, 0.027, and 0.018 for Cx43, Cx26, and Cx40, respectively. Cx43 channels were approximately 10 to 7 times more permeable to cAMP than Cx40 or Cx26 (Cx43 > Cx26 > or = Cx40), suggesting that these channels have distinctly different selectivity for negatively charged larger solutes involved in metabolic/biochemical coupling. These data suggest that Cx43 permeability to cAMP results in a rapid delivery of cAMP from cell to cell in sufficient quantity before degradation by phosphodiesterase to trigger relevant intracellular responses. The data also suggest that the reduced permeability of Cx26 and Cx40 might compromise their ability to deliver cAMP rapidly enough to cause functional changes in a recipient cell.     

Spectroscopic study of ALA-induced endogenous porphyrins in arthritic knee tissues: targeting rheumatoid arthritis PDT.

The inflamed synovium of rheumatoid arthritis exhibits many features typical for neoplastic tissue implying that the photodynamic therapy might be an efficient modality for chronic poliarthritis. The accumulation of endogenously produced porphyrins after administration of exogenous 5-aminolevulinic acid (ALA) in a rabbit model of rheumatoid arthritis was evaluated by fluorescence spectroscopy. Independent of the way, intravenously or intra-articularly, in which ALA was administered to the experimental animals, the highest fluorescence intensity of endogenously produced porphyrins was detected in the tissues of the inflamed joints. Besides, the application of ALA had a systemic sensitising effect on the whole organism of rabbits. The highest amount of endogenously produced porphyrins in the inflamed joints measured from the surface of the skin above the synovium tissues was detected 1-3 h after the administration of ALA. Fluorescence measurements performed on the tissue specimens ex vivo showed the predominant accumulation of porphyrins in the synovium of the inflamed joints. The fluorescence of porphyrins was also observed in the cartilage tissues taken from knee joints. However, the fluorescence spectra features indicated that the composition of porphyrins detected in the cartilage tissues was different than that in the synovial tissues. The selective accumulation of porphyrins in the inflamed synovial tissues stands up for the application of photodynamic therapy in the treatment of rheumatoid arthritis and implies the possibility to use optical non-invasive methods based on fluorescence detection of endogenously produced porphyrins for diagnostics of inflamed tissues.     

Bergmann’s rule for Neomys fodiens in the middle of the distribution range

The body size of Palearctic Sorex shrews decreases at higher latitudes, and as such the Bergmann’s rule does not work. However, no analysis has ever been done for water shrew (Neomys fodiens) in the middle of distribution range. Analysis of available literature data showed that some body and skull measurements of N. fodiens are negatively correlated to latitude. Measurements of 158 water shrews from Estonia and Lithuania were also analyzed with respect to the short scale latitudinal pattern. We found that populations are separated (Wilk’s lambda = 0.363, p<0.0001). Differences are related to PC1 (skull size), explaining 49.80% of the variance and PC2 (body size), explaining 10.06% of the variance. Estonian shrews are smaller in their body and skull (most differences significant) and their skulls are relatively shorter and wider in the area of the brain case. Thus, the negative correlation of body and skull size to latitude in N. fodiens is applicable even over quite short latitudinal distances. Further analysis of diagnostic characters between N. fodiens and N. anomalus is required.     

Can low concentrations of Papain help repair articular cartilage defects?

In the present study, we investigate the capability of low concentrations of Papain to stimulate cartilage mesenchymal cells proliferation and transformation to chondrocytes and evaluate the healing capability of partial thickness defects in medial condyle cartilage of 30 rabbits’ knee joints. Papain 0.1 mg/ml and Ringer saline l ml each were injected intra-articularly to rabbits of experimental and control groups (15 animals each). Healthy cartilage from lateral condyle and cartilage from medial condyle where the surgical defect was created were studied histologically and by TEM. The study revealed that 0.1 mg/ml Papain activates proliferation and spreading of mesenchymal stem cells to young forms of chondrocyte from perichondrium to the upper layers of healthy cartilage. In only 22.27% cases of the experimental group, surgical defects filled with cartilaginous tissue on the background of distinct destruction of collagenous matrix in the native cartilage. However, in 55.5% of the control group the defect was spontaneously healed by hyaline cartilaginous tissue completely or partially on the basis of slight destruction of collagenous matrix. The defect site was filled with activated chondrocyte-like cells from the subchondral plate (not perichondrium) in both groups, which acquired some cisterns of rough endoplasmic reticulum (RER) and produced matrix proteins. The results suggest that Papain did not ameliorate the recovery of cartilage defects acquired through surgically-induced injury of collagenous matrix in native cartilage. We observed that articular cartilage is the source of mesenchymal stem cells which have the ability to transform into young forms of chondrocytes. This transformation process depends on the level of destruction of native cartilage collagen matrix induced by the defect or by Papain.     

A new experimental setup for studying the formation of phosphate binding iron oxides in marine sediments. Preliminary results

A new laboratory method is introduced to study theformation of phosphate binding iron(III) oxides at theredox boundary in marine sediments. A sediment core isgiven a very well-defined oxic-anoxic interface byplacing a 0.45 µm filter between the sediment andthe overlying water. After a period of 1 months thefilter is covered with a layer of fresh iron oxides,formed by the oxidation of upward diffusing Fe²⁺from the sediment pore water. The formed iron oxidesare investigated by electron probe X-ray microanalysis(EXPMA). With a sediment core from the brackish BalticSea the average molar composition of 788 formedparticles is Fe_1.00±0.13P_0.55±0.06Ca_0.37±0.04 plus unknown amounts of O, H andC. The results show that the particles have a uniformcomposition, and that calcium plays an important rolein the phosphate binding. The laboratory method is auseful supplement to in situ sampling forstudies of iron oxides.