Intransitivity in plant-soil feedbacks is rare but is associated with multispecies coexistence

Although plant-soil feedback (PSF) is being recognized as an important driver of plant recruitment, our understanding of its role in species coexistence in natural communities remains limited by the scarcity of experimental studies on multispecies assemblages. Here, we experimentally estimated PSFs affecting seedling recruitment in 10 co-occurring Mediterranean woody species. We estimated weak but significant species-specific feedback. Pairwise PSFs impose similarly strong fitness differences and stabilizing-destabilizing forces, most often impeding species coexistence. Moreover, a model of community dynamics driven exclusively by PSFs suggests that few species would coexist stably, the largest assemblage with no more than six species. Thus, PSFs alone do not suffice to explain coexistence in the studied community. A topological analysis of all subcommunities in the interaction network shows that full intransitivity (with all species involved in an intransitive loop) would be rare but it would lead to species coexistence through either stable or cyclic dynamics.

The niche of a stress-tolerant specialist, Dinophysis acuminata, in a coastal upwelling system

Dinophysis acuminata, the main cause of shellfish harvesting bans in Europe, blooms in the Galician Rías (NW Spain) throughout the upwelling season (ca. March to September). Here we illustrate rapid changes in vertical and across ría-shelf distributions of diatoms and dinoflagellates (including D. acuminata vegetative and small cells) in Ría de Pontevedra (RP) and Ría de Vigo (RV) during transitions from spin-down to spin-up phases of upwelling cycles. A subniche approach based on a Within Outlying Mean Index (WitOMI) showed that under the transient environmental conditions met during the cruise, both vegetative and small cells of D. acuminata colonized the Ria and Mid-shelf subniches, exhibiting good tolerance and extremely high marginality, in particular the small cells. Bottom-up (abiotic) control overwhelmed biological constraints, and shelf waters became a more favourable environment than the Rías. Contrasting higher biotic constraints inside the Rías were found for the small cells, with a subniche possibly controlled by unsuitable physiological status (notwithstanding the higher density) of the vegetative cell population. Results here on behaviour (vertical positioning) and physiological traits (high tolerance but very specialized niche) of D. acuminata give new insights into the ability of this species to remain in the upwelling circulation system. Higher shelf-ría exchanges in the Ría (RP) with more dense and persistent D. acuminata blooms reveal the relevance of transient event-scales and species- and site-specific characteristics to the fate of these blooms. Earlier statements about simple linear relationships between average upwelling intensities and the recurrence of Harmful algae bloom (HAB) events in the Galician Rías Baixas are questioned.

Mapping dinoflagellate blooms (Noctiluca and Alexandrium) in aquaculture production areas in the NW Iberian Peninsula with the Sentinel-2/3 satellites

The Galician Rías (northwestern Spain) are periodically affected by harmful algal blooms (HABs), mostly dinoflagellates, which pose a challenge to aquaculture activities due to the accumulation of biotoxins in shellfish. Typically, reddish blooms in the Rías are associated with non-toxic species like Noctiluca scintillans, with a few exceptions such as Alexandrium minutum, a producer of paralytic shellfish toxins (PST). Here, a useful approach is presented for monitoring reddish blooms through satellite imagery based on three case studies, two of them belonged to monospecific blooms of red Noctiluca scintillans, and the third to a bloom of Alexandrium spp. dominated by A. tamarense. In every case, a propulsive index was evaluated using Sentinel-2A/B satellites, which provide high spatial and spectral resolutions, combined with adequate atmospheric and sunglint correction by using the ACOLITE and C2RCC processors. This approach offers a simple and feasible method to accurately and timely map blooms of red N. scintillans and Alexandrium spp. in the study area, useful to detect the distribution of reddish blooms with synoptic observations for monitoring and aquaculture management purposes. Conversely, Sentinel-3A/B satellites with a relatively coarser spatial resolution, lacking adequate visualization and mapping of the extent of small blooms, did not accurately detect bloom footprints in the coastal bay region, although this sensor displays a set of suitable multispectral bands.

Liver transplant with controlled donors after circulatory death with normothermic regional perfusion and brain dead donors: A multicenter cohort study of transfusion, one-year graft survival and mortality

BACKGROUND

Controlled donation after circulatory death (cDCD) has expanded the donor pool for liver transplantation (LT). However, transfusion requirements and perioperative outcomes should be elucidated. The aim of this multicenter study was to assess red blood cell (RBC) transfusions, one-year graft and patient survival after LT after cDCD with normothermic regional perfusion (NRP) compared with donors after brain death (DBD).

METHODS

591 LT carried out in ten centers during 2019 were reviewed. Thromboelastometry was used to manage coagulation and blood product transfusion in all centers. Normothermic regional perfusion was the standard technique for organ recovery.

RESULTS

447 patients received DBD and 144 cDCD with NRP. Baseline MCF Extem was lower in the cDCD group There were no differences in the percentage of patients (63% vs. 61% p = 0.69), nor in the number of RBC units transfused (4.7 (0.2) vs 5.5 (0.4) in DBD vs cDCD, p = 0.11. Twenty-six patients (6%) died during admission for LT in the DBD group compared with 3 patients (2%) in the cDCD group (p = 0.15). To overcome the bias due to a worse coagulation profile in cDCD recipients, matched samples were compared. No differences in baseline laboratory data, or in intraoperative use of RBC or one-year outcome data were observed between DBD and cDCD recipients.

CONCLUSIONS

cDCD with NRP is not associated with increased RBC transfusion. No differences in graft and patient survival between cDCD and DBD were found. Donors after controlled circulatory death with NRP can increasingly be utilized with safety, improving the imbalance between organ donors and the ever-growing demand.

Plant species abundance and phylogeny explain the structure of recruitment networks

Established plants can affect the recruitment of young plants, filtering out some and allowing the recruitment of others, with profound effects on plant community dynamics. Recruitment networks (RNs) depict which species recruit under which others. We investigated whether species abundance and phylogenetic distance explain the structure of RNs across communities. We estimated the frequency of canopy-recruit interactions among woody plants in 10 forest assemblages to describe their RNs. For each RN, we determined the functional form (linear, power or exponential) best describing the relationship of interaction frequency with three predictors: canopy species abundance, recruit species abundance and phylogenetic distance. We fitted models with all combinations of predictor variables, from which we simulated RNs. The best functional form of each predictor was the same in most communities (linear for canopy species abundance, power for recruit species abundance and exponential for phylogenetic distance). The model including all predictor variables was consistently the best in explaining interaction frequency and showed the best performance in predicting RN structure. Our results suggest that mechanisms related to species abundance are necessary but insufficient to explain the assembly of RNs. Evolutionary processes affecting phylogenetic divergence are critical determinants of RN structure.

19,19'-Diacyloxy Signature: An Atypical Level of Structural Evolution in Carotenoid Pigments

We report the isolation from the green dinoflagellate Lepidodinium chlorophorum and structural characterization of a new carotenoid termed lepidoxanthin (1), determined to be (3S,5R,6S,3'R,6'R)-5,6-epoxy-19-(2-decenoyloxy)-19'-acetoxy-4',5'-didehydro-5,6,5',6'-tetrahydro-β,ε-carotene-3,3'-diol. Its until now unidentified 19,19'-diacyloxy substitution constitutes a chemical signature that can aid in unraveling the evolutionary course of this unicellular algae based on the proposed biosynthethic pathway.

Pigment variations in Emiliania huxleyi (CCMP370) as a response to changes in light intensity or quality

Many studies on photoacclimation examine the pigment responses to changes in light intensity, but variations in light climate in the aquatic environment are also related to changes in spectral composition. We have employed a high-performance liquid chromatography method with improved resolution towards chlorophyll c and fucoxanthin-related xanthophylls to examine the pigment composition of Emiliania huxleyi CCMP 370 under different light intensities and spectral qualities. To maintain its photosynthetic performance, E. huxleyi CCMP370 promotes drastic pigment changes that can be either the interconversion of pigments in pools with the same basic chromophoric structure (Fucoxanthin type or chlorophyll c type), or the ex novo synthesis (Diatoxanthin). These changes are linked either to variations in light quality (Fucoxanthin related xanthophylls) or in light intensity (chlorophyll c₃ /Monovinyl chlorophyll c₃ , Diadinoxanthin/Diatoxanthin, β,ɛ-carotene/ β,β-carotene). Fucoxanthin and 19'-hexanoyloxyfucoxanthin proportions were highly dependent on spectral conditions. Whereas Fucoxanthin dominated in green and red light, 19'-hexanoyloxyfucoxanthin prevailed under blue spectral conditions. Our results suggest that the huge pigment diversity enhanced the photoacclimative capacities of E. huxleyi to efficiently perform under changing light environments. The ubiquity and success in the global ocean as well as the capacity of E. huxleyi to form large surface blooms might be associated to the plasticity described here.

30 years of preventive studies of uterine cervical cancer 1982-2012

The studies for the prevention of uterine cervical cancer in Panama City began in a private institute, impelled by the high incidence of cancer. The preventive programs were initiated with the support of the Obstetrics and Gynecology Institute of the University of Padua in Italy. In these studies, we applied the methodological diagnostics of this Institute with certain modifications adapted to our needs. The diagnosis, treatment, and follow-up were carried out under the protocol of the University of Padua. We achieved a diagnosis of oncogenic risk (OR) in 6,411 patients which corresponded to 5,498 cases of human papillomavirus (HPV), 1,150 cases of dysplasia, 210 cases of cancer, and 794 cases of OR. From 2011, polymerase chain reaction (PCR) was also applied with the aim to improve the accuracy of the diagnosis. With this method the prevalence of pathologies were HPV infections both in healthy patients or in patients cured from HPV. Patients were treated by means of local destructive treatments (LDT), basically with cryotherapy and cauterization. We can consider these results as successful prevention and suggest to extend a preventive program to all the population.

30 years of colposcopic studies: validity of local destructives treatments

The effectiveness of local destructive treatments (LDT) applied in patients due to cervical pathology oncogenic risk (OR), were followed and verified in 396 patients who came to our attention, focusing on the type of pathology, type of treatment received, diagnosis clinical evolutionary, and results of the new study applying polymerase chain reaction (PCR), and above all, the time between the diagnosis, treatment, and PCR findings. The clinical evolution of the same reports achieved a healing rate of 82% followed by persistence 8.3%; improvement 4.8%, recurrence 2.8%, and only one case of progression 0.2%. The elapsed time in initial care and treatment was almost immediate, as the pathology diagnosis was considered on an emergency basis. Successive controls of these indicated that 119 studies of routine colposcopy were carried out, on an average of the first three years and with a maximum follow up of 30 years, with over 30 routine colposcopies that achieved healing in most of these. In 2011 and 2012, we added to the usual diagnostic methodology, molecular biology, and 119 studies were performed in those patients, resulting in only five negative cases. Most studies were classified as high risk papillomavirus (HR-HPV), corresponding to subtypes 31, 35, 18, and 16.

The Use of HPLC for the Characterization of Phytoplankton Pigments

HPLC is still the technique of choice for the analysis and characterization of phytoplankton pigments. In this chapter we describe procedures for sample preparation and pigment extraction, and the use of octyl silica columns and pyridine-containing mobile phases to separate chlorophylls and carotenoids. The identification of pigments on the basis of their retention times and visible spectra, the preparation of pigment standards, and the quantitative analysis by either external or internal standard procedures are also described.

Nitrogen deposition in Spain: modeled patterns and threatened habitats within the Natura 2000 network

The Mediterranean Basin presents an extraordinary biological richness but very little information is available on the threat that air pollution, and in particular reactive nitrogen (N), can pose to biodiversity and ecosystem functioning. This study represents the first approach to assess the risk of N enrichment effects on Spanish ecosystems. The suitability of EMEP and CHIMERE air quality model systems as tools to identify those areas where effects of atmospheric N deposition could be occurring was tested. For this analysis, wet deposition of NO3(-) and NH4(+) estimated with EMEP and CHIMERE model systems were compared with measured data for the period 2005-2008 obtained from different monitoring networks in Spain. Wet N deposition was acceptably predicted by both models, showing better results for oxidized than for reduced nitrogen, particularly when using CHIMERE. Both models estimated higher wet deposition values in northern and northeastern Spain, and decreasing along a NE-SW axis. Total (wet+dry) nitrogen deposition in 2008 reached maxima values of 19.4 and 23.0 kg N ha(-1) year(-1) using EMEP and CHIMERE models respectively. Total N deposition was used to estimate the exceedance of N empirical critical loads in the Natura 2000 network. Grassland habitats proved to be the most threatened group, particularly in the northern alpine area, pointing out that biodiversity conservation in these protected areas could be endangered by N deposition. Other valuable mountain ecosystems can be also threatened, indicating the need to extend atmospheric deposition monitoring networks to higher altitudes in Spain.

Cervical dysplasias 1982-2010 in the Republic of Panama. Diagnosis, treatment, and evolution

The aim of this work was to demonstrate the effectiveness of colposcopic diagnosis and conservative local treatments in cases of dysplasia after colpo-cytology and directed biopsy. The main treatments applied were cryosurgery and cauterization. The association of dysplasia and human papillomavirus (HPV) showed an increase of 96% in recent years. The local destructive treatments (TLC), in addition to destroy the virus, have also successfully activated the local immunological system mechanism against HPV. The evidence of such affirmation is based on the obtained results that are: 76% cured, 11% improved, 6.8% persistent, 3.4% recurrence, and only one percent progression.

Genetic regulation of cold-induced albinism in the maize inbred line A661

In spite of multiple studies elucidating the regulatory pathways controlling chlorophyll biosynthesis and photosynthetic activity, little is known about the molecular mechanism regulating cold-induced chlorosis in higher plants. Herein the characterization of the maize inbred line A661 which shows a cold-induced albino phenotype is reported. The data show that exposure of seedlings to low temperatures during early leaf biogenesis led to chlorophyll losses in this inbred. A661 shows a high plasticity, recovering resting levels of photosynthesis activity when exposed to optimal temperatures. Biochemical and transcriptome data indicate that at suboptimal temperatures chlorophyll could not be fully accommodated in the photosynthetic antenna in A661, remaining free in the chloroplast. The accumulation of free chlorophyll activates the expression of an early light inducible protein (elip) gene which binds chlorophyll to avoid cross-reactions that could lead to the generation of harmful reactive oxygen species. Higher levels of the elip transcript were observed in plants showing a cold-induced albino phenotype. Forward genetic analysis reveals that a gene located on the short arm of chromosome 2 regulates this protective mechanism.

Spatial genetic structure of Aquilegia taxa endemic to the island of Sardinia

BACKGROUND AND AIMS

The Mediterranean Basin is one of the most important regions for the Earth's plant biodiversity; however, the scarcity of studies on fine scale patterns of genetic variation in this region is striking. Here, an assessment is made of the spatial genetic structure of all known locations of the three Sardinian endemic species of Aquilegia in order to determine the relative roles of gene flow and genetic drift as underlying evolutionary forces canalizing the divergence of Sardinian Aquilegia taxa, and to see if the spatial genetic structure found fits the current taxonomic differentiation of these taxa.

METHODS

DNA from 89 individuals from all known locations of Aquilegia across Sardinia was analysed by means of amplified fragment length polymorphism (AFLP) markers. Both principal co-ordinates analysis (PCoA) and Bayesian clustering analyses were used to determine the spatial genetic structure irrespective of any taxonomic affiliation. Historical effects of gene flow and genetic drift were assessed by checking for the existence of isolation-by-distance patterns.

KEY RESULTS

STRUCTURE and PCoA analyses revealed a pattern of genetic variation geographically structured into four spatial genetic groups. No migration-drift equilibrium was detected for Aquilegia in Sardinia, when analysed either as a whole or in individual groups. The scenario approached a Case III pattern sensu Hutchinson and Templeton, which is associated with extreme isolation conditions where genetic drift has historically played a dominant role over gene flow.

CONCLUSIONS

The pattern of genetic variation of Sardinian taxa of Aquilegia indicates that genetic drift has been historically more influential than gene flow on population structure of Sardinian species of Aquilegia. Limited seed dispersal and divergent selection imposed by habitat conditions have been probably the main causes reinforcing post-Pleistocene geographical isolation of Aquilegia populations. The spatial genetic structure found here is not fully compatible with current taxonomic affiliations of Sardinian Aquilegia taxa. This is probably a consequence of the uncoupling between morphological and genetic patterns of differentiation frequently found in recently radiated taxa.

Screening of cervical cancer: 27 years experience in six Republics of Panama

Between the years of 1983 and 2010, a program of screening of patients was conducted in six of the Republics of Panama, applying cytology, colposcopy, and directed biopsy when required. In the community of Pocri de Los Santos, a tour of 33 rural areas was included in 27 years of consecutive coverage. This allowed to confirm that application that screening was successful, resulting in initial, evolutionary, or final diagnoses. These were of extreme importance because they indicated the disease and its response to conservative treatments applied and to the fact that the cancer evolution was nil.

Twenty-five years of medical colposcopic rural tours in the Republic of Panama: commitment and integration in screening 1983-2008

Between the years 1983 and 2008, colposcopic rural tours were carried out which covered six provinces of the Republic of Panama, in which women in those areas were offered the opportunity of a preventive cervical-uterine cancer screening, applying cytology, colposcopy and directed biopsies (in those cases requiring it), as well as immediate treatment. The years of follow-up, especially in the community of Pocri de Los Santos, confirmed that application of the diagnostic methodology was successful, as an initial diagnosis, evolution and a closing prognosis were achieved. The prognosis is of utmost importance because it illuminated the response to the applied conservative treatments and moreover it pointed out zero evolutionary cancer.

OCCURRENCE OF LOROXANTHIN, LOROXANTHIN DECENOATE, AND LOROXANTHIN DODECENOATE IN TETRASELMIS SPECIES (PRASINOPHYCEAE, CHLOROPHYTA)(1)

The pigment composition of six species of Tetraselmis (Prasinophyceae) was analyzed using improved HPLC methods. All pigment extracts showed three peaks corresponding to unknown carotenoids. The isolated pigments were analyzed using UV-Vis spectroscopy, electrospray ionization-mass spectrometry (ESI-MS), and when carotenoid esters were suspected, gas chromatography-mass spectrometry (GC-MS) of the methyl ester and dimethyloxazoline derivative of the corresponding fatty acid. The new pigments were determined to be loroxanthin, loroxanthin 19-(2-decenoate), and loroxanthin 19-(2-dodecenoate); this is the first time these pigments have been described in the genus Tetraselmis. Moreover, this is the first report of esterification of 2-decenoic acid to loroxanthin. The relative contents of these pigments depended on the light regime, with the lowest proportions measured at the highest photon flux density assayed. The implications of the identification of these pigments in the genus Tetraselmis for the pigment types previously described in the class Prasinophyceae are discussed.

Giant fibrothecoma--an interesting case

A 45-year-old woman came for specialized medical attention due to intraabdominal pathology that began in 2003. Studies indicated the presence of a cyst in the right ovary, for which she was referred for surgery. She did not undergo the surgery and for a period of two years she suffered from an excessively enlarged abdomin. Posterior ultrasound studies indicated the presence of fibromatosis and she was again referred for surgery. Laparatomy was carried out and a giant cyst was found in the right ovary attached to the omentum, intestine, appendix, posterior side of the abdominal wall and to the uterus. We proceeded to remove the cyst and successively total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Post surgery, the patient progressed well taking pertinent prophylatic measures. The histopathology report diagnosed a giant fibrothecoma weighing 30 pounds, together with endometrial hyperplasia and leiomyomas. The international literature reports that the incidence of these tumors is low, 5% of ovarian tumors, and even lower for functioning tumors as in this case.

New splicing mutation of MEN1 gene affecting the translocation of menin to the nucleus

Multiple endocrine neoplasia type 1 (MEN1) is a syndrome inherited in an autosomal dominant trait caused by the inactivation of the tumor suppressor gene MEN1.

OBJECTIVE

To communicate a family with a new heterozygous germ line mutation in the intronic region of MEN1 gene and to study its influence in the menin expression.

PATIENTS AND METHODS

We studied 5 members of a family with symptomatic hyperparathyroidism (HPT). One of them had also a neuroendocrine pancreatic tumor, and 2 had non-functional multinodular cortical adrenal hyperplasia compatible with the diagnosis of MEN1. After the mutation was identified, HSP92II restriction enzyme was used to determine both zygosity and segregation of the mutation. RT-PCR from leukocyte's isolated mRNA and western blot from pancreatic tumor tissue were performed. In vitro studies were done in Chinese hamster ovary (CHO) cells transfected with reporter minigenes carrying the coding regions spanning exon (EX)-intron 9 and EX10 with the mutant and the wild type sequences.

RESULTS

We identified a heterozygous G-to-T substitution in the intron-EX junction (IVS9-1 G>T) of MEN1 gene in the index case and the family members. The mRNA from patient's leukocytes was larger (934 bp) in comparison to the normal transcript (717 bp). Immunoblot analysis demonstrated that wild type (67 kDa) and two additional mutant proteins (approximately 55 and approximately 90 kDa) were expressed in the pancreatic tissue. The in vitro study showed a 45% nuclear localization of the mutated menin signal and a 95% in the wild type protein.

CONCLUSIONS

We identified a new intronic heterozygous germ line mutation (IVS9-1G>T) of MEN1 gene in a family affected by MEN1 syndrome. This mutation alters the splice acceptor site of intron 9 that promotes an incorrect splicing, generating aberrant proteins without the nuclear localization signals necessary for the normal menin translocation to the nucleus.

The geographic mosaic in predispersal interactions and selection on Helleborus foetidus (Ranunculaceae)

We examine the hierarchical geographic structure of the interaction between a plant, Helleborus foetidus, and its floral herbivores and pollinators (interactors). Six populations from three distant regions of the Iberian Peninsula were used to examine intra- and inter-regional variation in plant traits, interactors and plant fecundity, and to compare, through selection gradient and path analyses, which traits were under selection, and which interactors were responsible for differential selection. Geographic and temporal congruency in interactor-mediated selection was further tested using a recent analytical approach based on multi-group comparison in Structural Equation Models. Most plant traits, interactors and fecundity differed among regions but not between populations. Similarly, the identity of the traits under selection, the selection gradients (strength and/or the direction of the selection) and the path coefficients (identifying the ecological basis for selection) varied inter- but not intra-regionally. Results show a selection mosaic at the broad scale and, for some traits, a link of differential selection to trait differentiation.

Rapid separation of chlorophylls a and b and their demetallated and dephytylated derivatives using a monolithic silica C18 column and a pyridine-containing mobile phase

A monolithic C18-bonded silica rod column (Merck Chromolith) was applied to the separation of mixtures of chlorophylls a and b and their derivatives originated by hydrolysis of the phytyl ester linkage (chlorophyllides), loss of the central Mg atom (pheophytins), or both processes (pheophorbides). Mobile phases containing two different ion-pair reagents, ammonium acetate and buffered pyridine, were tested. Both eluents achieved the resolution of the eight pigments in less than 5 min. The method based on the pyridine-containing mobile phase was applied to the separation of chlorophylls and their green coloured degradation products in senescing leaves of deciduous trees, green fruits and a marine microalga.

Activation of Wnt signaling rescues neurodegeneration and behavioral impairments induced by beta-amyloid fibrils

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, which is probably caused by the cytotoxic effect of the amyloid beta-peptide (Abeta). We report here molecular changes induced by Abeta, both in neuronal cells in culture and in rats injected in the dorsal hippocampus with preformed Abeta fibrils, as an in vivo model of the disease. Results indicate that in both systems, Abeta neurotoxicity resulted in the destabilization of endogenous levels of beta-catenin, a key transducer of the Wnt signaling pathway. Lithium chloride, which mimics Wnt signaling by inhibiting glycogen synthase kinase-3beta promoted the survival of post-mitotic neurons against Abeta neurotoxicity and recovered cytosolic beta-catenin to control levels. Moreover, the neurotoxic effect of Abeta fibrils was also modulated with protein kinase C agonists/inhibitors and reversed with conditioned medium containing the Wnt-3a ligand. We also examined the spatial memory performance of rats injected with preformed Abeta fibrils in the Morris water maze paradigm, and found that chronic lithium treatment protected neurodegeneration by rescuing beta-catenin levels and improved the deficit in spatial learning induced by Abeta. Our results are consistent with the idea that Abeta-dependent neurotoxicity induces a loss of function of Wnt signaling components and indicate that lithium or compounds that mimic this signaling cascade may be putative candidates for therapeutic intervention in Alzheimer's patients.

Protein kinase C inhibits amyloid beta peptide neurotoxicity by acting on members of the Wnt pathway

Current evidence supports the notion that the amyloid beta-peptide (Abeta) plays a major role in the neurotoxicity observed in the brain in Alzheimer's disease. However, the signal transduction mechanisms involved still remain unknown. In the present work, we analyzed the effect of protein kinase C (PKC) on some members of the Wnt signaling pathway and its implications for Abeta neurotoxicity. Activation of PKC by phorbol 12-myristate 13-acetate protected rat hippocampal neurons from Abeta toxicity. This effect was accomplished by inhibition of glycogen synthase kinase-3beta (GSK-3beta) activity, which led to the accumulation of cytoplasmic beta-catenin and transcriptional activation via beta-catenin/T-cell factor/lymphoid enhancer factor-1 (TCF/LEF-1) of Wnt target genes, which in the present study were engrailed-1 (en-1) and cyclin D1 (cycD1,). In contrast, inhibition of Ca2+-dependent PKC isoforms activated GSK-3beta and offered no protection from Ab neurotoxicity. Wnt-3a and lithium salts, classical activators of the Wnt pathway, mimicked PKC activation. Our results suggest that regulation of members of the Wnt signaling pathway by Ca2+-dependent PKC isoforms may be important in controlling the neurotoxic process induced by Ab.

Wnt signaling involvement in beta-amyloid-dependent neurodegeneration

Alzheimer's disease (AD) is a progressive dementia paralleled by selective neuronal death, which is probably caused by the cytotoxic effects of the amyloid-beta peptide (Abeta). We have observed that Abeta-dependent neurotoxicity induces a loss of function of Wnt signaling components and that activation of this signaling cascade prevent such cytotoxic effects. Therefore we propose that compounds which mimic this signaling cascade may be candidates for therapeutic intervention in Alzheimer's patients.

Diffuse uterine leiomyomatosis with ovarian and parametrial involvement

BACKGROUND

Diffuse uterine leiomyomatosis is a rare, benign entity and approximately 30 cases have been described previously.

CASE

A 42-year-old woman who complained of abdominal pain had a pelvic ultrasound scan showing a uterine mass. During the operation, the surgeon observed that both ovaries, the broad ligament, and the pelvis contained various nodules of striking size. On sectioning, uterus and ovaries contained multiple nodules of elastic consistency; microscopically, all consisted of benign smooth muscle tissue.

CONCLUSION

Leiomyomatosis may exhibit concomitant parametrial, pelvic, and bilateral ovarian involvement.

THE MAIN NONPOLAR CHLOROPHYLL c FROM EMILIANIA HUXLEYI (PRYMNESIOPHYCEAE) IS A CHLOROPHYLL c 2 -MONOGALACTOSYLDIACYLGLYCERIDE ESTER: A MASS SPECTROMETRY STUDY

The main nonpolar chlorophyll c -like pigment was extracted from Emiliania huxleyi (Lohm.) Hay et Mohler (strain CCMP 370) cultures and isolated by preparative column chromatography and HPLC. The pigment, whose visible spectrum closely resembled that of chlorophyll c ₂ , was studied by low-resolution fast atom bombardment mass spectrometry, showing a very high mass molecular ion (m/z 1313). The fragment ions, either in the direct spectrum or obtained by tandem mass spectrometry with collision-induced dissociation of the molecular ion, were compatible with the consecutive losses of two fatty acids (14:0 and 18:4), glycerol, and a hexose, leaving a chlorophyll c ₂ backbone, suggesting the molecule consists of a chlorophyll c ₂ residue linked, via an ester bond, to the sugar moiety of a monohexosyldiacylglycerol. The identities of the two fatty acid residues (14:0 and 18:4n-3) were subsequently corroborated by gas chromatography of the corresponding methyl esters. Chemical hydrolysis-derivatization-gas chromatography-mass spectrometry demonstrated the occurrence of glycerol and that galactose is the constituent sugar. The porphyrin obtained on acid hydrolysis showed chromatographic and visible spectral properties identical to pheoporphyrin c ₂ . This evidence led us to propose a tentative structure whose molecular formula, C₇₆ H₉₆ O₁₄ N₄ Mg, was supported by the values of exact mass measurements by high-resolution fast atom bombardment mass spectrometry. This novel structure represents the highest molecular weight natural chlorophyll described to date.

Antineoplastic activity of BCG: location of antineoplastic glycans in the cellular integument of Mycobacterium bovis, BCG vaccine, Connaught substrain

The polysaccharidic integument surrounding growing cells of attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccine, Connaught substrain, can be removed with non-specific proteases. After 5 weeks incubation at 37 degrees C in Middlebrook 7H-9 medium, the collected cells were incubated with pronase and the integument and cells separated by centrifugation in a Ficoll-Histopaque preparation. After washing and drying, the detached integument accounted for 65% w/w of the original dried cell mass. Like the original cellular material, the detached integument manifested antineoplastic activity against a murine sarcoma model in vivo. Solubilization of the otherwise insoluble integument by boiling in water or by digestion in 8 M urea significantly enhanced activity of the integument itself, by 125 and 1,100 times, respectively. Integument extracts were shown to contain mainly glucose, with smaller quantities of other sugars, consistent with the presence in BCG of high molecular weight glycans, as previously reported. It is suggested that most, if not all, of the antineoplastic activity of BCG can be accounted for by the activity associated with the high-molecular weight polysaccharidic glycans which constitute the cellular integument.

Chemical and ultrastructural investigations of Mycobacterium bovis BCG: implications for the molecular structure of the mycobacterial cell envelope

The mycobacterial cell wall visualized by transmission electron microscopy (TEM) of thin sections of resin-embedded specimens is generally believed to consist of an electron-dense peptidoglycan, an electron-transparent arabinogalactanmycolate layer and an electron-dense outer layer (OL). In addition, a pseudocapsule known as the 'electron-transparent zone' (ETZ) has been observed after phagocytosis of mycobacteria by macrophages. TEM of thin sections of Mycobacterium bovis BCG, Tice substrain, revealed an OL bilayer, each of which measured 2-4 nm in diameter. The intermediate electron-transparent layer varied from 1 to about 250 nm in diameter and appears to be a previously observed oxygen-dependent amorphous integument that consists of hot water-extractable neutral polysaccharides, especially a recently characterized alpha glucan, comprising about 12% of the dry cell weight. This and other recent studies of BCG have revealed cell-surface features that may provide a better understanding of the outer mycobacterial cell envelope.

Separation of mono- and divinyl chlorophyll species by high-performance liquid chromatography using an octadecyl polyvinyl alcohol polymer column

Most of the chlorophylls and their related compounds from nonesterified chlorophyllide to esterified pheophytin were separated by high- performance liquid chromatography using a wide pore, C(18) polyvinyl alcohol polymer column with an elution using a binary gradient starting from a buffered mobile phase. The high selectivity of this system enabled not only the separation of common chlorophyll species but also the resolution of structurally similar compounds such as mono- and divinyl chlorophyllide and pheophorbide species which usually coelute on monomeric bonded phases. The method is successfully applied to analyses of the pigments extracted from green and etiolated tissues of higher plants and photosynthetic bacterial cells.