Yolk‐sac larval development of the substrate‐brooding cichlid Archocentrus nigrofasciatus in relation to temperature

In order to conserve and culture the cichlid fish Archocentrus nigrofasciatus, more information about its reproductive biology and its larval behavior and morphogenesis is necessary. Currently, temperatures ranging from 21 to 27 °C are used in ornamental aquaculture hatcheries. Lower temperatures are preferred to reduce the costs of water heating, and 23 °C is usually the selected temperature. However, there is limited information on culturing protocols for ornamental species and most of the information generated on this topic remains scarce. Thus, the present study examines the morphological development of Archocentrus nigrofasciatus during the yolk‐sac period up to the age of 100 h post‐hatching in relation to 2 temperature regimes used in ornamental aquaculture: a temperature of 27 °C (thermal optimum) and a decreased temperature of 23 °C (thermal tolerance). The results of this study suggest that the 27 °C temperature generates intense morphological changes in yolk‐sac development in a shorter period. This has advantages as it reduces the time of yolk‐sac larval development, and, thus, minimizes the transition phase to exogenous feeding and maximizes the efficiency at which yolk is converted into body tissues. The present paper provides necessary information to produce freshwater ornamental fish with better practices so as to increase larval survival and capitalize on time for growth.     

Irrigating Onions and Potatoes with Chromium and Nickel: Its Effects on Catalase and Peroxidase Activities and the Cross-Contamination of Plants

Tropospheric ozone (O₃) has long been documented to cause an injury to plants, but a plants’ protectant, widely applicable in agronomical practice, does not exist. We evaluated the potential antiozonate efficacy of the antitranspirant di-1-p-menthene (Vapor Gard) compared with ethylenediurea (EDU) on Bel-W3 tobacco plants. Plants were treated either with water, or by EDU (10, 100, and 500 mg dm^?3), or by vapor (1, 5, 10, and 50 ml dm^?3) and were exposed either to O₃-enriched (90 ppb) or O₃-free air, for 12 days and 8 h day^?1. EDU when applied at 10 mg dm^?3 did not protect the plants against O₃, but when applied at 100 and 500 mg dm^?3 offered a significant protection to the plants. Vapor, when applied at 1 ml dm^?3 did not protect the plants against O₃, neither by terms of foliar visible injury nor by terms of aboveground biomass. In addition, when applied at 10 and 50 ml dm^?3 caused phytotoxicity to all the plants, which it was expressed as necrotic spots on the leaves’ surface, misshaping of the leaves, or short plants' height_. It is obvious that vapor does not protect Bel-W3 tobacco plants against O₃. The antiozonate role of di-1-p-menthene is species-specific and probably occurs only under short-term exposures.     

Structure and flexibility adaptation in nonspecific and specific protein-DNA complexes

Interaction of regulatory DNA binding proteins with their target sites is usually preceded by binding to nonspecific DNA. This speeds up the search for the target site by several orders of magnitude. We report the solution structure and dynamics of the complex of a dimeric lac repressor DNA binding domain with nonspecific DNA. The same set of residues can switch roles from a purely electrostatic interaction with the DNA backbone in the nonspecific complex to a highly specific binding mode with the base pairs of the cognate operator sequence. The protein-DNA interface of the nonspecific complex is flexible on biologically relevant time scales that may assist in the rapid and efficient finding of the target site.     

Occurrence of Organotin Compounds in the Aquatic Environment of Greece

The presence of organotin (OT) compounds was investigated in coastal areas (10 stations), wastewater treatment systems (six stations), rivers (19 stations) and lakes (12 stations) throughout Greece, in three sampling campaigns organized between October 1998 and September 1999. A screening method for the determination of toluene extractable organotins (TEOTs) by Electrothermal Atomic Absorption Spectrometry (ETAAS) was used during the first two sampling campaigns. TEOTs (sum of tributyltin, TBT, dibutyltin, DBT and triphenyltin, TPhT) were detected in most seawater and wastewater samples at concentrations up to 19.4 and 89.9 ng l^?1, respectively, while they were detected occasionally in surface water. During the third sampling campaign, OT compounds were extracted in selected stations using direct derivatization with NaBEt₄ in acidic medium and analysed by Gas Chromatography–Mass Spectrometry (GC–MS). In seawater, the levels of TBT, DBT and monobutyltin (MBT) were varied between < 2 and 70, 159 and 19 ng l^?1, respectively and tend to decrease with increasing distance from the coastline. TPhT was not detected in any of the samples. Significant concentrations of OT species were detected in influent wastewater, up to 384, 76.2 and 67.8 ng l^?1 for TBT, DBT and MBT, respectively. OTs were mainly associated with the suspended solids and were totally removed during wastewater treatment.     

A Study of Glycemic Response to Corinthian Raisins in Healthy Subjects and in Type 2 Diabetes Mellitus Patients

This study was designed to evaluate the metabolic response to Corinthian raisins in healthy and in patients with type 2 diabetes mellitus. Healthy subjects (n?=?15) and diabetic patients (n?=?15) received 74 g raisins or 50 g glucose as reference food. Blood samples were collected at time 0 (before the consumption) and 30, 60, 90, 120, 150 and 180 min after raisin or glucose consumption. There was no significant difference in baseline glucose and insulin between raisins and reference in both groups. The difference at glucose peaks between raisins and reference was significant in healthy and in diabetics. Glycemic and insulinemic responses were decreased after raisin consumption compared to reference. An estimate of the glycemic index would be 66.3?±?3.4.     

Influence of biotic factors on the mechanical properties of wood,taking into account the time of harvesting

The aim of the present paper is to investigate the influence of biotic factors (fungi and insects) on the mechanical properties of wood through the effect of blue-stain, taking into account the time of harvesting and the time of stay of wood in the forest. Specifically, the resistance to axial compression and to bending (modulus of rupture (MOR)) was studied using infected specimens of Scots Pine (Pinus sylvestris) and Norway Spruce (Picea abies) (the usual types of wood used in woodwork). The specimens were obtained from logs of Scots Pine and Norway Spruce that were harvested in three different seasons of year, namely in July 2012, November 2012 and June 2013, respectively, in the forest of Elatia-Greece, and the attack pace by biotic factors with respect to the time of logging was studied. The placement of the experimental surfaces of each type of tree was made on skid road and in the stand. Totally, 120 laboratory measurements in axial compression and 120 measurements in bending (MOR) took place. The results proved that blue-stain hardly affect the mechanical properties of both wooden species and particularly the specimens that were derived during the winter logging.     

Comparison of the radical scavenging potential of polar and lipidic fractions of olive oil and other vegetable oils under normal conditions and after thermal treatment

The antioxidant activity (IC(50)) of extra virgin olive oil (EVOO), commercial olive oil, and other vegetable oils (soybean, sunflower, and corn oil) was determined by UV-vis and by electron paramagnetic resonance (EPR) spectroscopy of the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Also, we studied the antioxidant activity of the methanol soluble phase (methanolic, MF) and the nonsoluble phase (lipidic, LF) of oils by the same methods. Similarly, we studied the effect of heating on the antioxidant activity at 160 and 190 degrees C. Also, the MF, containing the polyphenolic substances, was used for measurements of the radical scavenging capacity toward the most important oxygen free radicals, superoxide anion (O(2)(*)(-)) and hydroxyl (HO(*)) radicals. Results showed that soybean oil and EVOO had the highest antioxidant potential and thermal stability. In the case of soybean oil, the antioxidant capacity is the result of its high content of gamma- and delta-tocopherols (with the highest antioxidant capacity and thermostabilities), whereas in EVOO, the antioxidant potential is the result of the combination of specific antioxidant polyphenols, which are acting additionally as effective stabilizers of alpha-tocopherol. The high content of EVOO in tyrosol, hydrotyrosol, and oleuropein and other polyphenolics with radical scavenging abilities toward superoxide anion and hydroxyl radical suggests that olive oil possesses biological properties that could partially account for the observed beneficial health effects of the Mediterranean diet.