Oviducal glands throughout the gonad development stages: a case study of Octopus mimus (Cephalopoda)

The oviducal glands (ODG) play a crucial role in octopus reproduction. Herein, structural changes of each section of the ODG of Octopus mimus are described histologically throughout the gonad development stages (GDS). To do this, the epithelial height, stereociliated or non-stereociliated epithelium, nucleus type (pycnotic or non-pycnotic), epithelial secretions and the value range of the macroscopic maturity index (MaMI), which directly involves ODG status, were measured. The ODG are internally constituted of two glandular units (central and peripheral glands) and one set of receptacles (the spermathecae). High epithelia (40 to 80?μm) were observed in both gland units during periods with low MaMI values (< 0.1) corresponding to III-mature and IV-pre-spawning. The stereociliated epithelium was only apparent in II-maturing and III-mature in both gland units. The nuclei were noticeably pycnotic in the central gland during III-mature, IV-pre-spawning and V-spawning, but pycnotic in the peripheral gland only during VI-depletion. The epithelium was disorganised during VI-depletion, while sulphated acid mucin was only present during III-mature in the central gland. The epithelium transformations during the GDS are related to the functions of the gland units and to their multiple secretions. The ODG histology complements the GDS and provides better reproductive status assessment.     

Evaluation of molecular techniques for the genetic characterization of Saccharomyces cerevisiae strains

The applicability of different PCR-based techniques, random amplified polymorphic DNA, cleaved amplified polymorphic sequence and SSRs (simple sequence repeats) to genetically identify, typify and discriminate among Saccharomyces cerevisiae strains, was investigated. The analysis and comparison of the genetic profiles obtained for each of the techniques allowed determination of the degree of polymorphism, genetic diversity and relationships among the strains. Consequently, the discriminatory power and usefulness of the molecular techniques assayed was established. SSR analysis was the most effective method due to its high level of polymorphism, the ease of interpretation of the genetic profiles obtained, and the speed of use.     

Cryopreservation of in vitro-grown shoot-tips of hop (Humulus lupulus L.) using encapsulation/dehydration

 A cryopreservation procedure using encapsulation/dehydration was established for shoot-tips obtained from in vitro-grown shoots of hop. After dissection, shoot-tips were encapsulated in medium with alginate and 0.5 M sucrose. Optimal conditions consisted of preculture for 2 days in solid medium with 0.75 M sucrose, or in increasing sucrose concentrations, desiccation for 4 h with silicagel in a flow cabinet (16% water content) followed by rapid freezing and slow thawing. Shoot recovery after freezing 60 min in liquid nitrogen was around 80%. No phenotypical changes were observed in the recovered plants from cryopreserved shoot-tips growing in the field. Received: 20 April 1997 / Revised: 20 February 1998 / Accepted: 1 Dezember 1998     

Effects of ascorbate feeding on chlorophyll fluorescence and xanthophyll cycle components in the lichen Parmelia quercina (Willd.) Vainio exposed to atmospheric pollutants

The effects of environmental stresses on photosynthetic responses, ascorbate levels and pigment composition were investigated in samples of Parmelia quercina (Willd.) Vainio from control and polluted regions of the northern Castellón area (Valencia, Spain). In response to sustained pollutant stress in the field, lichen thalli had closed PSII traps and exhibited lower rates of electron transport and non-radiative energy dissipation. The xanthophyll concentration was not affected by exposure to atmospheric pollutants. The ascorbate concentration was lower in samples exposed to ambient air pollutants compared to control thalli. Ascorbate feeding of thalli from polluted sites stimulated electron flow, photochemical quenching and non-radiative energy dissipation. Additionally, ascorbate feeding enhances the de-epoxidation state of the xanthophyll pool in polluted thalli. The partial recovery for non-radiative energy dissipation was presumably due to the interaction between the increased thylakoid pH gradient and de-epoxidized xanthophylls. Furthermore, ascorbate feeding decreased photon excess in thalli from polluted sites owing to the stimulation of linear electron flow and non-radiative energy dissipation. The present study suggests that atmospheric pollutants, besides their intrinsic toxicity, put on an additional burden by hampering the operation of photoprotective mechanisms.     

Interaction between Calcite and Phosphorus in Biomineralization Processes in Tufa Carbonates

Using electron microscopy techniques (SEM, LTSEM) coupled with analytical methods (XRD and EDS) the role of phosphorus has been assessed in the formation of freshwater calcite deposits (tufa) in a small pond of the Ruidera Lakes (Spain). Differences between the cell walls and sheaths of bacteria and eukaryotic algae as well as the existence of additional layers of extracellular polymeric substances (EPS) were features that lead to differences in the process of induced calcite biomineralization. Phosphorus has influence in the biomineralization of the EPS, sheaths and cell walls of cyanobacteria allowing for fossil preservation whereas does not participate in the calcite precipitation around algae and mosses. This variability may explain the different positive or negative roles played by natural or artificial inputs of phosphorus in hard water lakes and the different morphological features of calcite precipitates associated with eukaryotic and cyanobacteria picoplankton found in natural environments. The biomineralization observed is in agreement with the isotopic composition of the tufa layers that reflect the variations in environmental conditions around biological communities. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Expression of MAL, an integral protein component of the machinery for raft-mediated pical transport, in human epithelia.

The MAL protein is the only integral membrane protein identified as being an essential component of the machinery necessary for apical transport in the canine MDCK cell line, a paradigm of polarized epithelial cells. To characterize the range of human epithelia that use MAL-mediated pathways of transport, we performed an immunohistochemical survey of normal tissues using a monoclonal antibody (MAb) specific for the MAL protein. For comparison, different types of carcinoma were also analyzed. MAL, with a characteristic strong supranuclear granular distribution, was detected in specific types of normal epithelial cells throughout the respiratory system, the gastrointestinal and genitourinary tracts, and in exocrine and endocrine glands. Absorptive cells (e.g., enterocytes), and many different types of specialized secretory cells, either organized in discrete clusters (e.g., endocrine cells in the pancreas), gathered together in an endocrine gland (e.g., thyroid), interspersed with other cells in glands (e.g., parietal cells), or dispersed singly among other cells (e.g., type 2 pneumocytes) were positive for MAL. We also analyzed a series of epithelial renal and thyroid tumors and found alterations dependent on the particular histological type of tumor. These results open potential applications of the anti-MAL antibody for the characterization of neoplastic tissue.     

Patterns of β‐diversity in a Mexican tropical dry forest

Abstract. Patterns of β‐diversity in a highly diverse tropical dry forest tree community are described; the contribution of environmental heterogeneity and distance to β‐diversity was assessed. Significant differences in elevation, insolation, slope and soil water holding capacity (p < 0.01), variables related to water availability, were found among 830 m × 100 m transects laid along contrasting slopes of a system of three parallel microbasins. A gradient in elevation and insolation was found within north‐facing transects, among 10 m × 10 m sites; south‐facing transects showed an elevation gradient while crest transects showed a gradient in water holding capacity. In total 119 species were registered, with 27 to 64 species per transect, and 4 to 16 species per site. A large β‐diversity was found among and within transects; two indices of β‐diversity consistently showed a higher β‐diversity within transects than among them. Among transects, 64% of the variance in species composition could be attributed to the environmental variables; an additional 22% to the spatial distribution of sites. Within transects, 42% of the deviance in β‐diversity values was explained by insolation, and 19% by distance. β‐diversity increased with distance and with difference in insolation among sites; north‐facing transects, those with most contrasting insolation conditions, had the steepest increase in β‐diversity with distance. Such increase was clearly associated with changes in species composition, not with changes in species richness.     

Peroxidases and the metabolism of capsaicin in Capsicum annuum L.

Capsaicinoids are acid amides of C₉ - C₁₁ branched-chain fatty acids and vanillylamine. These compounds are responsible for the pungency of the Capsicum species and of cultivars regarded as hot peppers. Moreover, it has been suggested that these compounds play an ecological role in seed dispersal. Because they are used in the pharmacological, food and pesticide industries, much attention has been paid on knowing how their accumulation is controlled, both in the fruit and in cell cultures. Such control involves the processes of biosynthesis, conjugation and catabolism. Recent progress has been made on the biosynthetic pathway, and several of the genes coding for biosynthetic enzymes have been cloned and expression studies performed. With regard to catabolism, cumulative evidence supports that capsaicinoids are oxidized in the pepper by peroxidases. Peroxidases are efficient in catalyzing in vitro oxidation of both capsaicin and dihydrocapsaicin. These enzymes are mainly located in placental and the outermost epidermal cell layers of pepper fruits, as occurs with capsaicinoids, and some peroxidases are present in the organelle of capsaicinoid accumulation, that is, the vacuole. Hence, peroxidases are in the right place for this function. The products of capsaicin oxidation by peroxidases have been characterized in vitro, and some of them have been found to appear in vivo in the Capsicum fruit. Details on the kinetics and catalytic cycle for capsaicin oxidation by peroxidases are also discussed.     

Dendritic cell-specific ICAM-3-grabbing nonintegrin expression on M2-polarized and tumor-associated macrophages is macrophage-CSF dependent and enhanced by tumor-derived IL-6 and IL-10

Dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN; CD209) is a human pathogen-attachment C-type lectin with no obvious murine ortholog and for which ligation leads to enhanced anti-inflammatory cytokine release and altered proinflammatory cytokine production. Although induced by IL-4 in monocytes and considered as a DC marker, DC-SIGN expression on human APCs under homeostatic conditions is so far unexplained. We report in this study that M-CSF enhances DC-SIGN expression on in vitro derived anti-inflammatory macrophages and that M-CSF mediates the induction of DC-SIGN by fibroblast- and tumor cell-conditioned media. The M-CSF-inducible DC-SIGN expression along monocyte-to-macrophage differentiation is dependent on JNK and STAT3 activation, potentiated by STAT3-activating cytokines (IL-6, IL-10), and abrogated by the M1-polarizing cytokine GM-CSF. In pathological settings, DC-SIGN expression is detected in tumor tissues and on ex vivo-isolated CD14(+) CD163(+) IL-10-producing tumor-associated macrophages. Importantly, DC-SIGN Abs reduced the release of IL-10 from macrophages exposed to Lewis(x)-expressing SKBR3 tumor cells. These results indicate that DC-SIGN is expressed on both wound-healing (IL-4-dependent) and regulatory (M-CSF-dependent) alternative (M2) macrophages and that DC-SIGN expression on tumor-associated macrophages might help tumor progression by contributing to the maintenance of an immunosuppressive environment.