Age-dependent changes in body size of Greek boys from 1982 to 2002

Objective: The prevalence of childhood obesity has been rising during the past decades in many parts of the world, including Greece. The dispersion of these trends across age, however, is less clear. The aim of this study was to examine the relationship between age and 20‐year changes in anthropometric characteristics of Greek boys. Research Methods and Procedures: A total of 204 and 106 boys 9 years old, 163 and 274 boys 12 years old, and 161 and 240 boys 15 years old were randomly recruited in 1982 and 2002, respectively, throughout the county of Iraklio, Crete, Greece. Height, weight, and BMI were measured. Results: Contemporary 9 and 12 year olds were taller than their peers in 1982 (+2.9% and +1.2%, respectively; p < 0.005), but this was not the case for 15 year olds (?0.8%; p = 0.083). Body weight and BMI were higher now than in the 1980s, and this held true for all age groups (p < 0.001). Increases in weight also showed a decline with advancing age (+17.4%, +13.9%, and +4.0% for 9, 12, and 15 year olds, respectively), whereas BMI changes were similar for those 9 and 12 years of age (～10.5%), but were almost 2‐fold higher than in 15 year olds (+5.5%). Discussion: Contemporary boys are taller, heavier, and have higher BMI values than their peers in 1982, but the magnitude of these increases gradually declines with advancing age. Rates of increase in BMI, however, seem to have greatly accelerated compared with previous decades.     

Dinucleotide spore photoproduct, a minimal substrate of the DNA repair spore photoproduct lyase enzyme from Bacillus subtilis

The overwhelming majority of DNA photoproducts in UV-irradiated spores is a unique thymine dimer called spore photoproduct (SP, 5-thymine-5,6-dihydrothymine). This lesion is repaired by the spore photoproduct lyase (SP lyase) enzyme that directly reverts SP to two unmodified thymines. The SP lyase is an S-adenosylmethionine-dependent iron-sulfur protein that belongs to the radical S-adenosylmethionine superfamily. In this study, by using a well characterized preparation of the SP lyase enzyme from Bacillus subtilis, we show that SP in the form of a dinucleoside monophosphate (spore photoproduct of thymidilyl-(3'-5')-thymidine) is efficiently repaired, allowing a kinetic characterization of the enzyme. The preparation of this new substrate is described, and its identity is confirmed by mass spectrometry and comparison with authentic spore photoproduct. The fact that the spore photoproduct of thymidilyl-(3'-5')-thymidine dimer is repaired by SP lyase may indicate that the SP lesion does not absolutely need to be contained within a single- or double-stranded DNA for recognition and repaired by the SP lyase enzyme.     

Activities of de-N-glycosylation are ubiquitously found in tomato plant

Activities of two de-N-glycosylation enzymes, PNGase (peptide N ⁴(N-acetyl-glucosaminyl)asparagine amidase) and ENGase (endo N-acetyl-β-D-glucosaminidase), involved in the release of N-glycans from N-glycoproteins, were monitored in several organs of tomato plants (Lycopersicon esculentum, Mill., cv. Dombito) with a fluorescence-HPLC procedure using a resofurin-labelled N-glycopeptide substrate. PNGase and ENGase activities were detected in every organ assayed but with quantitative differences. The highest activities were found in the youngest parts of the plant, i.e. apical buds, flowers and leaf blades. PNGase activities were consistently higher than ENGase activities (three-fold in average). Both de-N-glycosylation activities were associated with high levels of proteins and protease activities. During fruit growth and ripening, these three parameters decreased notably. The ubiquitous detection of these enzyme activities in the different organs is probably associated with the previously characterized unconjugated N-glycans in tomato. The possible role of PNGase and ENGase degradation products (i.e. unconjugated N-glycans) are discussed in relation with their biological functions in plant development.     

Lumican, a small leucine-rich proteoglycan substituted with keratan sulfate chains is expressed and secreted by human melanoma cells and not normal melanocytes

Melanoma is a frequent and therapy-resistant human disease. Malignant melanocytes modulate their microenvironment in order to penetrate the dermal/epidermal junction and eventually invade the dermis. The small leucine-rich proteoglycans (SLRPs) constitute important constituents of the dermis extracellular matrix (ECM), participating in both the structural and the functional organization of the skin. The role of a keratan sulphate SLRP lumican, has recently been investigated in the growth and metastasis of several cancers. In this study, the expression of lumican was studied in two human melanoma cell lines (WM9, M5) as well as in normal neonatal human melanocytes (HEMN) using real time PCR, western blotting with antibodies against the protein core and keratan sulfate, and treatments with specific enzymes. Both human metastatic melanoma cell lines were found to express lumican mRNA and effectively secrete lumican in a proteoglycan form, characterized to be substituted mostly with keratan sulfate chains. Lumican mRNA was not detected in normal melanocytes. This is the first time that the synthesis and secretion of lumican in human melanoma cell lines is reported. The role of this proteoglycan in the development and progression of malignant melanoma has to be further investigated.     

The Biology of Small Leucine-rich Proteoglycans in Bone Pathophysiology

The class of small leucine-rich proteoglycans (SLRPs) is a family of homologous proteoglycans harboring relatively small (36–42 kDa) protein cores compared with the larger cartilage and mesenchymal proteoglycans. SLRPs have been localized to most skeletal regions, with specific roles designated during all phases of bone formation, including periods relating to cell proliferation, organic matrix deposition, remodeling, and mineral deposition. This is mediated by key signaling pathways regulating the osteogenic program, including the activities of TGF-β, bone morphogenetic protein, Wnt, and NF-κB, which influence both the number of available osteogenic precursors and their subsequent development, differentiation, and function. On the other hand, SLRP depletion is correlated with degenerative diseases such as osteoporosis and ectopic bone formation. This minireview will focus on the SLRP roles in bone physiology and pathology.     

Site quality effects on post‐fire regeneration of Pinus brutia forest on a Greek island

Abstract. Natural stands of Pinus brutia were compared to burned areas after a great fire in 1985 on the island of Thasos, North Greece, in relation to site quality effects on the success of natural regeneration and understorey vegetation. The number of seedlings in the natural stands of P. brutia was 1124/ha against 3188/ha in the burned area. In both cases natural regeneration was successful. Under the canopy of P. brutia forests the predominant shrubs were Quercus coccifera and vPhillyrea latifolia. A high percentage (up to 40%) of the total area was covered by these species. In the burned areas, 12 yr after the wildfire of 1985, Cistus incanus and C. salvifolius played a significant role in the survival of P. brutia seedlings. These species had covered the burned area long before the pine seed germination.     

Intestinal eversion in a pelagic shark evokes chase and bite attempts by large-bodied carangid fish

Journal of Ethology - Expelling indigestible objectives through the cloaca is an important cleansing behaviour for several species of higher vertebrates. Although intestinal eversions are short in...     

Quantification of nematic cell polarity in three-dimensional tissues

How epithelial cells coordinate their polarity to form functional tissues is an open question in cell biology. Here, we characterize a unique type of polarity found in liver tissue, nematic cell polarity, which is different from vectorial cell polarity in simple, sheet-like epithelia. We propose a conceptual and algorithmic framework to characterize complex patterns of polarity proteins on the surface of a cell in terms of a multipole expansion. To rigorously quantify previously observed tissue-level patterns of nematic cell polarity (Morales-Navarrete et al., eLife 2019), we introduce the concept of co-orientational order parameters, which generalize the known biaxial order parameters of the theory of liquid crystals. Applying these concepts to three-dimensional reconstructions of single cells from high-resolution imaging data of mouse liver tissue, we show that the axes of nematic cell polarity of hepatocytes exhibit local coordination and are aligned with the biaxially anisotropic sinusoidal network for blood transport. Our study characterizes liver tissue as a biological example of a biaxial liquid crystal. The general methodology developed here could be applied to other tissues and in-vitro organoids.     

Generation of supercoils in nicked and gapped DNA drives DNA unknotting and postreplicative decatenation

Due to the helical structure of DNA the process of DNA replication is topologically complex. Freshly replicated DNA molecules are catenated with each other and are frequently knotted. For proper functioning of DNA it is necessary to remove all of these entanglements. This is done by DNA topoisomerases that pass DNA segments through each other. However, it has been a riddle how DNA topoisomerases select the sites of their action. In highly crowded DNA in living cells random passages between contacting segments would only increase the extent of entanglement. Using molecular dynamics simulations we observed that in actively supercoiled DNA molecules the entanglements resulting from DNA knotting or catenation spontaneously approach sites of nicks and gaps in the DNA. Type I topoisomerases, that preferentially act at sites of nick and gaps, are thus naturally provided with DNA–DNA juxtapositions where a passage results in an error-free DNA unknotting or DNA decatenation.     

Foraging ecology of Cookiecutter Sharks (<Emphasis Type="Italic">Isistius brasiliensis</Emphasis>) on pelagic fishes in Hawaii,inferred from prey bite wounds

The Cookiecutter Shark (Isistius brasiliensis) is an ecto-parasitic predator of numerous large pelagic fish and mammals. However, little is known of its foraging ecology due to its elusive foraging tactics in the pelagic environment. We used bite scar patterns on pelagic fishes landed at the Honolulu Fish Auction to assess some of the Cookiecutter Shark foraging habits. Swordfish (Xiphias gladius) had the greatest percentage of bites (87.9 ± 25.0% of individuals had healed scars) followed by Opah (Lampris guttatus, 33.0 ± 8.3% of individuals). Most fish with scars only had one Cookiecutter Shark bite per individual with the exception of Swordfish, which often had >5 bites per individual. Furthermore, Swordfish had a higher proportion of healed bite scars meaning they had been attacked while free-swimming. Seasonal changes in the probability of hooked fish being bitten by sharks were apparent for Swordfish, Bigeye Tuna and Opah. Based on bite scar diameter, larger Cookiecutter Sharks may preferentially attack Swordfish rather than the other species of pelagic fish. When taken in conjunction with diving behavior of pelagic fish, and fishing depths, the results add further support to the hypothesis that Cookiecutter Sharks perform diel vertical migrations.