Short and medium-term effects of two-phase olive mill waste application on olive grove production and soil properties under semiarid mediterranean conditions

A five-year field study was conducted to evaluate the potential use of oiled and de-oiled two-phase olive mill waste (TPOMW and DTPOMW, respectively) as soil amendment on a representative olive grove soil: a Cutanic Luvisol. Treatments included a non-amended control, TPOMW1, TPOMW2, DTPOMW1 and DTPOMW2 (30, 60, 27 and 54Mgha(-1) dry weight equivalent). Significant increases (P<0.05) in organic carbon, total N, available P and K, and aggregate stability were observed in the amended soils. Leaf analysis showed significant increases in N, P, and K concentrations in treated plots after the two first years of TPOMW or DTPOMW amendments. Also, a general increase in olive production was observed in the treated plots, this increase being higher in the TPOMW1 and DTPOMW1 treated soils. After five years of repeated TPOMW and DTPOMW application, the increase in yield was 29%, 9.8%, 30%, and 19% for TPOMW1, TPOMW2, DTPOMW1, and DTPOMW2, respectively. Raw TPOMW and DTPOMW have the potential to be valuable soil amendments and source of organic matter, with a positive effect on olive yield, and closing the cycle of residues-resources.     

Metabolic modulation induced by oestradiol and DHT in immature rat Sertoli cells cultured in vitro

Sertoli cells actively metabolize glucose that is converted into lactate, which is used by developing germ cells for their energy metabolism. Androgens and oestrogens have general metabolic roles that reach far beyond reproductive processes. Hence, the main purpose of this study was to examine the effect of sex hormones on metabolite secretion/consumption in primary cultures of rat Sertoli cells. Sertoli cell-enriched cultures were maintained in a defined medium for 50?h. Glucose and pyruvate consumption, and lactate and alanine secretion were determined, by 1H-NMR (proton NMR) spectra analysis, in the presence or absence of 100?nM E2 (17β-oestradiol) or 100?nM 5α-DHT (dihydrotestosterone). Cells cultured in the absence (control) or presence of E2 consumed the same amount of glucose (29±2?pmol/cell) at similar rates during the 50?h. After 25?h of treatment with DHT, glucose consumption and glucose consumption rate significantly increased. Control and E2-treated cells secreted similar amounts of lactate during the 50?h, while the amount of lactate secreted by DHT-treated cells was significantly lower. Such a decrease was concomitant with a significant decrease in LDH A [LDH (lactate dehydrogenase) chain A] and MCT4 [MCT (monocarboxylate transporter) isoform 4] mRNA levels after 50?h treatment in hormonally treated groups, being more pronounced in DHT-treated groups. Finally, alanine production was significantly increased in E2-treated cells after 25?h treatment, which indicated a lower redox/higher oxidative state for the cells in those conditions. Together, these results support the existence of a relation between sex hormones action and energy metabolism, providing an important assessment of androgens and oestrogens as metabolic modulators in rat Sertoli cells.     

Calmodulin activity and cAMP signalling modulate growth and apical secretion in pollen tubes

Our present understanding implicates both calmodulin (CaM) and 3',5'-cyclicAMP (cAMP) in the regulation of pollen tube growth. However, downstream molecules of these signalling pathways and the cellular processes they modulate remain largely unknown. In order to elucidate the role of CaM, we mapped its activity in growing pollen tubes. 2-chloro-(epsilon-amino-Lys(75))-[6-4-(N,N'-diethylaminophenyl)-1,3,5-triazin-4-yl]-calmodulin (TA-CaM) and fluorescein-calmodulin (FL-CaM), fluorescent analogues of CaM, were loaded into pollen tubes and CaM activity was mapped by fluorescence ratio imaging. It was found that CaM activity exhibits a tip-focused gradient, similar to the distribution of cytosolic-free calcium ([Ca(2+)](c)). In long pollen tubes, apical CaM activity was also found to oscillate with a period similar to [Ca(2+)](c) (40-80 sec). This oscillatory behaviour was not observed in small pollen tubes or in tubes that had stopped growing. Changes in CaM activity within the dome of the pollen tube apex resulting from the photolysis of caged photolysis of RS-20 (a peptide antagonist of CaM) induced re-orientation of the growth axis, suggesting that CaM is also involved in the guidance mechanism. CaM activity was strongly modulated by intracellular changes in cAMP (induced by activators and antagonists of adenylyl cyclase). These results indicate that the action of this protein is dependent not solely on [Ca(2+)](c) but also on a cross-talk with other signalling pathways. A putative target of this cross-talk is the secretory machinery as observed in pollen tubes loaded with the FM (N-(3-triethylammoniumpropyl)-4-(4-dibutylamino)styryl)pyridinium dibromide 1-43 dye and exposed to different antagonists and activators of these molecules. Our data thus suggest that pollen tube growth and orientation depend on an intricate cross-talk between multiple signalling pathways in which CaM is a key element.     

Asymmetric localization of <Emphasis Type="Italic">Arabidopsis</Emphasis> SYP124 syntaxin at the pollen tube apical and sub-apical zones is involved in tip growth

Background  

The continuous polarized vesicle secretion in pollen tubes is essential for tip growth but the location of endo- and exocytic sub-domains remains however controversial. In this report we aimed to show that Arabidopsis thaliana syntaxins are involved in this process and contribute to spatially define exocytosis and membrane recycling.     

Tubular Fluid Secretion in the Seminiferous Epithelium: Ion Transporters and Aquaporins in Sertoli Cells

Sertoli cells play a key role in the establishment of an adequate luminal environment in the seminiferous tubules of the male reproductive tract. Secretion of the seminiferous tubular fluid (STF) is vital for the normal occurrence of spermatogenesis and for providing a means of transport to the developing spermatozoa. However, several studies on this subject have not completely clarified the origin and composition of this fluid. Electrolyte and water are central components of STF. Sertoli cells secrete an iso-osmotic fluid with a higher content of K⁺ than the blood and express various membrane and water transporters (Na⁺/K⁺-ATPase; Ca²⁺-ATPase; V-type ATPase; Cl⁻ channels; CFTR Cl⁻ channels; K⁺ channels; L-, T- and N-type Ca²⁺ channels; Na⁺/H⁺ exchangers; Na⁺-driven HCO₃ ⁻/Cl⁻ exchangers (NDCBEs); Na⁺/HCO₃ ⁻ cotransporters (NBCes); Na⁺–K⁺–2Cl⁻ cotransporter; Na⁺/Ca²⁺ exchanger; and aquaporins 0 and 8) involved in cellular and secretory functions. Studies with knockout mice for some of these transporters showed tubular fluid accumulation and associated infertility, revealing the relevance of these processes for the normal occurrence of spermatogenesis. Nevertheless, the role of the several membrane transporters in the establishment of STF electrolyte composition needs to be further elucidated. This review summarizes the available data on the ionic composition of STF and on the Sertoli cell membrane mechanisms responsible for ion and water movement. Deepening the knowledge on the mechanisms involved in the secretion, composition and regulation of SFT is essential and will be a major step in understanding the infertility associated with some pathological conditions.     

Variation in morphology and functional performance across distinct evolutionary lineages of the Moorish gecko (Tarentola mauritanica) from the Iberian Peninsula

Deciphering the mechanisms that underlie morphological and functional diversity is essential for understanding how organisms adapt to their environment. Interestingly, phenotypic divergence does not necessarily correspond to the geographic and genetic separation between populations. Here, we explored the morphological and functional divergence among populations of two genetically differentiated clades of the Moorish gecko, Tarentola mauritanica. We used linear and geometric morphometrics to quantify morphological variation and investigated how it translates into biting and CLIMBING PERFORMANCE, to better understand the mechanisms potentially underlying population and lineage divergence. We found marked morphological differences between clades, both in body size and head shape. However, much of this differentiation is more strongly related to local variation between populations of the same clade, suggesting that recent ecological events may be more influential than deep evolutionary history in shaping diversity patterns in this group. Despite a lack of association between morphology and functional diversification in the locomotor system of the Moorish gecko, straightforward links are observed between head morphology and biting performance, providing more hints on the possible underlying causes. Indeed, variation in bite force is mostly determined by size variation and sexual dimorphism, and differences between the two clades concern how sexual variation is expressed, reinforcing the idea that both social and ecological factors contribute in shaping differentiation. Interestingly, the individuals from the islets off the coast of Murcia exhibit particular morphological and functional traits, which suggests that the ecological conditions related to insularity may drive the phenotypic differentiation of this population.     

Short-term effects on soil properties and wheat production from secondary paper sludge application on two Mediterranean agricultural soils

This study was conducted under greenhouse conditions to evaluate the potential use of SPS as a fertilizer, amendment and/or liming agent for wheat (Triticum aestivum L.). Two representative Mediterranean agricultural soils, a Cambic Arenosol (cmAR) and a Cromic Cambisol (crCM) were used. Treatments included four sludge rates ranging from 0 to 40 g kg(-1) (equivalent of 0, 38, 88 and 120 Mg ha(-1)). A significant increment in soil pH, organic carbon, N total, available P and exchangeable K were observed in both soils. Sludge application significantly increased N and decreased Zn, Mn and Cu concentrations in wheat. Wheat grain yields were reduced by 33% and 37% when 120 Mg SPS ha(-1) was applied to cmAR and crCM soils, respectively, due apparently to unavailability of Mg. However, straw yields, with much lower Mg requirements, increased significantly with SPS rates. Secondary pulp mill sludge seems to be a potential source of organic matter, N, P, K and a potential soil amendment liming agent for acid soils, when appropriate supplemental fertilizer was provided. For grain crops grown in these soils, addition of Mg is required for proper nutrient balance.