Physiological function of water channels as affected by salinity in roots of paprika pepper

The sap flow (Jv) and the osmotic pressure-dependent hydraulic conductance (L₀) of detached exuding root systems from paprika pepper plants (cv. Albar) were measured. Plants stressed with NaCl (30 m M ) and with six times the macronutrients of the Hoagland nutrient solution (6×HNS) were compared with controls grown in complete Hoagland nutrient solution. Jv of +NaCl and +6×HNS plants decreased markedly, but recovered to values similar to those of controls after removal of the treatments. Hydraulic conductance L₀ was always less in NaCl plants than in controls and 6×HNS. A total increase in the ion concentration of the xylem (except Na⁺ and Cl⁻) was observed with both treatments. In control and 6×HNS plants, HgCl₂ treatment (50 μ M ) caused a sharp decline in L₀ to values similar to those of NaCl-stressed roots, but were restored by treating with 5 m M dithiothreitol (DTT). However, in NaCl roots only a slight effect of Hg²⁺ and DTT was observed. In each treatment, there was no difference in the flux of K⁺ into the xylem after HgCl₂ and DTT application. The results suggest that NaCl decreased L₀ of the roots by reducing either the activity or abundance of Hg-sensitive water channels. The putative reduction in water-channel function of NaCl-treated plants did not seem to be due to the osmotic effect.     

Enhancement of fruit byproducts through bioconversion by Hermetia illucens (Diptera: Stratiomyidae)

Bioconversion is a biological process by which organic materials are converted into products with higher biological and commercial value. During its larval stage the black soldier fly Hermetia illucens is extremely voracious and can feed on a wide variety of organic materials. To study the impact of different fruit byproducts on the insect's growth, final larval biomass, substrate reduction, bioconversion parameters, and larval nutritional composition, 10 000 black soldier fly larvae (BSFL) were reared on 7.0 kg of one of three substrates (strawberry, tangerine, or orange) or on a standard diet as a control. The results highlight that BSFL can successfully feed and grow on each of these diets, though their development time, growth rate, and final biomass were differently impacted by the substrates, with strawberry being the most suitable. The lipid and protein contents of BSFL were similar among larvae fed on different substrates; however, major differences were detected in ash, micronutrient, fiber, fatty acid, and amino acid contents. Overall, the results indicate that fruit waste management through the BSFL bioconversion process represents a commercially promising resource for regional and national agrifood companies. Our study offers new perspectives for sustainable and environmentally friendly industrial development by which fruit byproducts or waste might be disposed of or unconventionally enhanced to create secondary products of high biological and economic value, including BSFL biomass as animal feed or, in perspective, as alternative protein source for human nutrition.     

C-Peptide-Based Assessment of Insulin Secretion in the Zucker Fatty Rat: A Modelistic Study

A C-peptide-based assessment of β-cell function was performed here in the Zucker fatty rat, a suitable animal model of human metabolic syndrome. To this aim, a 90-min intravenous glucose tolerance test (IVGTT) was performed in seven Zucker fatty rats (ZFR), 7-to-9week-old, and seven age-matched Zucker lean rats (ZLR). The minimal model of C-peptide (CPMM), originally introduced for humans, was adapted to Zucker rats and then applied to interpret IVGTT data. For a comprehensive evaluation of glucose tolerance in ZFR, CPMM was applied in combination with the minimal model of glucose kinetics (GKMM). Our results showed that the present CPMM-based interpretation of data is able to: 1) provide a suitable fit of C-Peptide data; 2) achieve a satisfactory estimation of parameters of interest 3) quantify both insulin secretion by estimating the time course of pre-hepatic secretion rate, SR(t), and total insulin secretion, TIS, and pancreatic sensitivity by means of three specific indexes of β-cell responsiveness to glucose stimulus (first-phase, Ф₁, second-phase, Ф₂, and steady-state, Ф_ss, never assessed in Zucker rats before; 4) detect the significant enhancement of insulin secretion in the ZFR, in face of a severe insulin-resistant state, previously observed only using a purely experimental approach. Thus, the methodology presented here represents a reliable tool to assess β-cell function in the Zucker rat, and opens new possibilities for the quantification of further processes involved in glucose homeostasis such as the hepatic insulin degradation.     

Response of three broccoli cultivars to salt stress, in relation to water status and expression of two leaf aquaporins

The aim of this study was to compare differences in water relations in the leaves of three broccoli cultivars and differential induction of the expression of PIP2 aquaporin isoforms under salt stress. Although broccoli is known to be moderately tolerant to salinity, scarce information exists about the involvement of leaf aquaporins in its adaptation to salinity. Thus, leaf water relations, leaf cell hydraulic conductivity (Lp_c), gas exchange parameters and the PIP2 expression pattern were determined for short- (15 h) and long- (15 days) term NaCl treatments. In the long term, the lower half-time of water exchange in the cells of cv. Naxos, compared with Parthenon and Chronos, and its increased PIP2 abundance may have contributed to its Lp_c maintenance. This unmodified Lp_c in cv. Naxos under prolonged salinity may have diluted NaCl in the leaves, as suggested by lower Na⁺ concentrations in the leaf sap. By contrast, the increase in the half-time of water exchange and the lower PIP2 abundance in cvs. Chronos and Parthenon would have contributed to the reduced Lp_c values. In cv. Parthenon, there were no differences between the ε values of control and salt-stressed plants; in consequence, cell turgor was enhanced. Also, the increases in BoPIP2;2 and BoPIP2;3 expression in cv. Chronos for the short-term NaCl treatment suggest that these isoforms are involved in osmotic regulation as downstream factors in this cultivar, in fact, in the short-term, Chronos had a significantly reduced osmotic potential and higher PIP2 isoforms expression.     

Clinical,ultrasonographic, and endocrinological studies on donkey pregnancy

Although donkey breeding has gained new interest in the past two decades, knowledge about donkey reproduction is still scarce, particularly on jenny pregnancy. The aim of this study was to describe the ultrasonographic and endocrine profiles of the physiological pregnancy in the jenny. The study was performed on 12 pregnancies of 7 Amiata donkeys from Day 10 after ovulation to delivery. Because three pregnancies, respectively at weeks 42, 44, and 45, were considered pathologic and treated pharmacologically, data collected from 2 weeks before diagnosis to the end of pregnancy were removed from the analysis. Average length of the normal pregnancies was 353.4 ± 13.0 days (range, 339–370 days). Timing, dimensions, and development during the first phases of embryonic growth, evaluated using transrectal ultrasound, were similar to that previously described in jennies and mares: first detection of embryonic vesicle was at 11.8 ± 1.3 days of gestation and diameter was 6.5 ± 1.9 mm, loss of spherical shape occurred at 18.5 ± 1.4 days, and embryo and heart beat were first seen at 22.0 ± 1.1 and 25 ± 1.1 days, respectively. The intrauterine growth in the second half of pregnancy, evaluated using the transrectal and transabdominal approach, also showed strong positive correlations, similar to that reported for the mare. The trends of the combined thickness of the utero-placental unit and the echogenicity of the amniotic and allantoic fluids are examples. The diameters (mm) of fetal chest, eye orbit, and aorta increased throughout pregnancy and were 40.6 ± 2.9, 8.7 ± 1.5, and 3.5 ± 0.7, respectively, at week 13, and 190.9 ± 12.0, 21.4 ± 1.5, and 30.6 ± 1.8 at the last evaluation before parturition. In contrast, heart rate decreased as pregnancy progressed. Regression analyses between these parameters and day of gestation were statistically significant (P < 0.001). All fetuses consistently showed some intrauterine activity. Maternal plasma progestagens and estrone sulfate concentrations followed a pattern similar to that seen in mares, although the prepartal progestagen peak was lower in jennies. This study provides a range of ultrasonographic and endocrine values for normal pregnancy in jennies.     

Characterization and expression analysis of SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) genes in sexual and apomictic Paspalum notatum

The SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) gene plays a fundamental role in somatic embryogenesis of angiosperms, and is associated with apomixis in Poa pratensis. The objective of this work was to isolate, characterize and analyze the expression patterns of SERK genes in apomictic and sexual genotypes of Paspalum notatum. A conserved 200-bp gene fragment was amplified from genomic DNA with heterologous primers, and used to initiate a chromosomal walking strategy for cloning the complete sequence. This procedure allowed the isolation of two members of the P. notatum SERK family; PnSERK1, which is similar to PpSERK1, and PnSERK2, which is similar to ZmSERK2 and AtSERK1. Phylogenetic analyses indicated that PnSERK1 and PnSERK2 represent paralogous sequences. Southern-blot hybridization indicated the presence of at least three copies of SERK genes in the species. qRT-PCR analyses revealed that PnSERK2 was expressed at significantly higher levels than PnSERK1 in roots, leaves, reproductive tissues and embryogenic calli. Moreover, in situ hybridization experiments revealed that PnSERK2 displayed a spatially and chronologically altered expression pattern in reproductive organs of the apomictic genotype with respect to the sexual one. PnSERK2 is expressed in nucellar cells of the apomictic genotype at meiosis, but only in the megaspore mother cell in the sexual genotype. Therefore, apomixis onset in P. notatum seems to be correlated with the expression of PnSERK2 in nucellar tissue.     

Quantitative assessment of dielectric parameters for membrane lipid bi‐layers from RF permittivity measurements

In this article, we propose and validate theoretical and experimental methods to quantitatively assess the Debye dielectric model of membrane lipid bi‐layers. This consists of two steps: permittivity measurements of biological solutions (liposomes), and estimation of the model parameters by inverse application of the Effective Medium Theory. The measurements are conducted in the frequency domain between 100 MHz and 2 GHz using a modified coaxial connector, at the temperatures of 27 and 30 °C. Estimations have been performed using a three‐layered model based on the Maxwell–Wagner formulation. Debye parameters (mean value ± standard error) found from fitting experimental data are: ε_s = 11.69 ± 0.09, ε_∞ = 4.00 ± 0.07, f_relax = 179.85 ± 6.20 MHz and ε_s = (1.1 ± 0.1) × 10^?7 S/m. This model can be used in microdosimetric studies aiming to precisely determine the E‐field distribution in a biological target down to the single cell level. In this context the use of an accurate membrane dielectric model, valid through a wide frequency range, is particularly appropriate. Bioelectromagnetics 30:286–298, 2009. © 2009 Wiley‐Liss, Inc.