Differential distribution of tau proteins in developing cat cerebellum.

The differential distribution and phosphorylation of tau proteins in cat cerebellum was studied with two well characterized antibodies, TAU-1 and TAU-2. TAU-1 detects tau proteins in axons, and the epitope in perikarya and dendrites is masked by phosphorylation. TAU-2 detects a phosphorylation-independent epitope on tau proteins. The molecular composition of tau proteins in the range of 45 kD to 64 kD at birth changed after the first postnatal month to a set of several adult variants of higher molecular weights in the range of 59 kD to 95 kD. The appearance of tau proteins in subsets of axons corresponds to the axonal maturation of cerebellar local-circuit neurons in granular and molecular layers and confirms previous studies. Tau proteins were also identified in synapses by immunofluorescent double-staining with synapsin I, located in the pinceau around the Purkinje cells, and in glomeruli. Dephosphorylation of juvenile cerebellar tissue by alkaline phosphatase indicated indirectly the presence of differentially phosphorylated tau forms mainly in juvenile ages. Additional TAU-1 immunoreactivity was unmasked in numerous perikarya and dendrites of stellate cells, and in cell bodies of granule cells. Purkinje cell bodies were stained transiently at juvenile ages. During postnatal development, the intensity of the phosphate-dependent staining decreased, suggesting that phosphorylation of tau proteins in perikarya and dendrites may be essential for early steps in neuronal morphogenesis during cat cerebellum development.

Standardization and evaluation of ELISA for the serodiagnosis of amoebic liver abscess

An ELISA test for the serological diagnosisof amoebic liver abscess (ALA) was standardized and evaluated in sera from three groups of patients: (1) three patients with diagnosis confirmed by isolation of the parasite,(2) thirty seven patients with diagnosis established by clinical findings and ultrasound studies and (3) seven patients whose diagnosis were established by clinical findings and a positive double immunodifusion test. Ninety one serum samples from healthy subjects and 22 from patients with other liver or parasitic diseases were also included in the study. the optimum concentration of Entamoeba histolytica antigen was 1.25 µg/ml and optimum dilutions of serum and anti-human IgG-alkaline phosphatase conjugate were 1:400 and 1:4000 respectively. The cut-off point of the ELISA test in this study was an absorbance value of 0.34. The test parameters were: sensitivity = 95.7 per cent, specificty = 100 per cent, positive predictive value = 100 per cent and negative predictive value = 98.2 per cent.The ELISA test was found to be of great use as a diagnostic tool for the establishment of amoebic etiology in patients with clinical supposition of ALA. The test could also be used for seroepidemiological surveys of the prevalence of invasive amoebiasis in a given population, since it allows the processing of a greater number of samples at a lower cost tahn other serological tests.

Timing of Palaeozoic magmatism in the Maggia and Sambuco nappes and paleogeographic implications (Central Lepontine Alps)

Magmatic rocks from the pre-Mesozoic basements of the Sambuco and Maggia nappes have been dated by U-Pb zircon ages with the LA-ICPMS technique. Several magmatic events have been identified in the Sambuco nappe. The mafic banded calc-alkaline suite of Scheggia is dated at 540 Ma, an age comparable to that of mafic rocks in the Austroalpine Silvretta nappe. The Sasso Nero peraluminous augengneiss has an age of 480-470 Ma, like many other ``older orthogneisses'' in Alpine basement units. It hosts a large proportion of inherited zircons, which were dated around 630 Ma, a Panafrican age indicating the Gondwanan affiliation of the Sambuco basement. The calc-alkaline Matorello pluton yielded ages around 300 Ma, similar to numerous Late Carboniferous intrusions in other basement units of the Lower Penninic (Monte Leone, Antigorio, Verampio) and Helvetic domains (Gotthard and other External Crystalline Massifs). Associated lamprophyric dykes are slightly younger (300-290 Ma), like similar dykes sampled in gneiss blocks included in the sedimentary cover of the underlying Antigorio nappe (290-285 Ma). The Cocco granodiorite and Ruscada leucogranite, both intruding the basement of the neighbouring Maggia nappe, yielded ages of ca. 300-310 Ma, identical within errors to the age of the Matorello pluton. They are significantly older than former age determinations. This age coincidence, coupled with remarkable petrologic similarities between the Cocco and Matorello granodiorites, strongly suggests paleogeographic proximity of the Sambuco and Maggia nappes in Late Carboniferous times. In recent publications these two nappes have been interpreted as belonging to distinct Mesozoic paleogeographic domains: ``European'' for Sambuco and ``Brian double dagger onnais'' for Maggia, separated by the ``Valais'' oceanic basin. In this case, the similarity of the Matorello and Cocco intrusions would demonstrate the absence of any significant transcurrent movement between these two continental domains. Alternatively, according to a more traditional view, Sambuco and Maggia might belong to a single large Alpine tectonic unit.

Lipoxin A4 is a novel estrogen receptor modulator.

Inflammation is intimately linked with naturally occurring remodeling events in the endometrium. Lipoxins comprise a group of short-lived, nonclassic eicosanoids possessing potent anti-inflammatory and proresolution properties. In the present study, we investigated the role of lipoxin A(4) (LXA(4)) in the endometrium and demonstrated that 15-LOX-2, an enzyme necessary for LX biosynthesis, is expressed in this tissue. Our results establish that LXA(4) possesses robust estrogenic activity through its capacity to alter ERE transcriptional activity, as well as expression of estrogen-regulated genes, alkaline phosphatase activity, and proliferation in human endometrial epithelial cells. Interestingly, LXA(4) also demonstrated antiestrogenic potential, significantly attenuating E2-induced activity. This estrogenic activity was directly mediated through estrogen receptors (ERs). Subsequent investigations determined that the actions of LXA(4) are exclusively mediated through ERα and closely mimic those of the potent estrogen 17β-estradiol (E2). In binding assays, LXA(4) competed with E2 for ER binding, with an IC(50) of 46 nM. Furthermore, LXA(4) exhibited estrogenic activity in vivo, increasing uterine wet weight and modulating E2-regulated gene expression. These findings reveal a previously unappreciated facet of LXA(4) bioactions, implicating this lipid mediator in novel immunoendocrine crosstalk mechanisms.

Trypanosoma cruzi defined antigens in the serological evaluation of an outbreak of acute Chagas disease in Brazil (Catolé do Rocha, Paraíba)

Immunoglobulin G and M humoral response to recombinant protein B13 and glycoconjugate LPPG Trypanosoma cruzi defined antigens was evaluated by ELISA in 18 patients in the acute phase of Chagas disease, who were contaminated on the same occasion. LPPG showed 100% positivity detecting both IgM and IgG antibodies, while positivity of 55-65% was observed for B13. An epimastigote alkaline extract (EPI) also showed high sensitivity for acute IgM (100%) and IgG (90%) antibodies. However LPPG had better discriminatory reactivity since with EPI two patients showed negative IgG and several other sera presented OD values for IgG and IgM antibodies very close to the cutoff. Thus, it is suggested that detection of IgM antibodies by LPPG may be used for diagnosis of the acute phase of Chagas disease. An intense decline of IgG and IgM antibodies to the three antigens was observed in response to anti-T. cruzi chemotherapy in all acute phase patients. After treatment, six (30%) individuals maintained IgG positivity to EPI, LPPG, and B13 with lower reactivity than that measured at the acute phase. For comparison, serology of a group of 22 patients in the chronic phase of Chagas disease and also submitted to chemotherapy was determined. Positive IgM antibodies to EPI, LPPG and B13 were detected in only 5-9% cases. In all chronic-phase patients IgG antibodies highly reactive to the three antigens were present and no significant decrease resulted after benznidazole administration. These observations reinforce previous reports that treatment in the acute phase may reduce or eliminate the parasite.

Biochemical, immunological and toxicological characteristics of the crystal proteins of Bacillus thuringiensis subsp. medellin

Characterization of the insecticidal and hemolytic activity of solubilized crystal proteins of Bacillus thuringiensis (Bt) subsp. medellin (Btmed) was performed and compared to solubilized crystal proteins of isolates 1884 of B. thuringiensis subsp. israelensis (Bti) and isolate PG-14 of B. thuringiensis subsp. morrisoni (Btm). In general, at acid pH values solubilization of the Bt crystalline parasporal inclusions (CPI) was lower than at alkaline pH. The larvicidal activity demonstrated by the CPI of Btmed indicated that optimal solubilization of CPI takes place at a pH value of 11.3, in Bti at pH values from 5.03 to 11.3 and in Btm at pH values from 9.05 to 11.3. Hemolytic activity against sheep red blood cells was mainly found following extraction at pH 11.3 in all Bt strains tested. Polyacrylamide gel electrophoresis under denaturing conditions revealed that optimal solubilization of the CPI in all Bt strains takes place at the alkaline pH values from 9.05 to 11.3. An enriched preparation of Btmed crystals was obtained, solubilized and crystal proteins were separated on a size exclusion column (Sephacryl S-200). Three main protein peaks were observed on the chromatogram. The first peak had two main proteins that migrate between 90 to 100 kDa. These proteins are apparently not common to other Bt strains isolated to date. The second and third peaks obtained from the size exclusion column yielded polypeptides of 68 and 28-30 kDa, respectively. Each peak independently, showed toxicity against 1st instar Culex quinquefasciatus larvae. Interestingly, combinations of the fractions corresponding to the 68 and 30 kDa protein showed an increased toxicity. These results suggest that the 94 kDa protein is an important component of the Btmed toxins with the highest potency to kill mosquito larvae. When crystal proteins of Bti were probed with antisera raised independently against the three main protein fractions of Btmed, the only crystal protein that showed cross reaction was the 28 kDa protein. These data suggest that Btmed could be an alternative bacterium for mosquito control programs in case mosquito larval resistance emerges to Bti toxic proteins.

Therapeutic hypothermia for traumatic brain injury.

Experimental evidence demonstrates that therapeutic temperature modulation with the use of mild induced hypothermia (MIH, defined as the maintenance of body temperature at 32-35 °C) exerts significant neuroprotection and attenuates secondary cerebral insults after traumatic brain injury (TBI). In adult TBI patients, MIH has been used during the acute "early" phase as prophylactic neuroprotectant and in the sub-acute "late" phase to control brain edema. When used to control brain edema, MIH is effective in reducing elevated intracranial pressure (ICP), and is a valid therapy of refractory intracranial hypertension in TBI patients. Based on the available evidence, we recommend: applying standardized algorithms for the management of induced cooling; paying attention to limit potential side effects (shivering, infections, electrolyte disorders, arrhythmias, reduced cardiac output); and using controlled, slow (0.1-0.2 °C/h) rewarming, to avoid rebound ICP. The optimal temperature target should be titrated to maintain ICP <20 mmHg and to avoid temperatures <35 °C. The duration of cooling should be individualized until the resolution of brain edema, and may be longer than 48 h. Patients with refractory elevated ICP following focal TBI (e.g. hemorrhagic contusions) may respond better to MIH than those with diffuse injury. Randomized controlled trials are underway to evaluate the impact of MIH on neurological outcome in adult TBI patients with elevated ICP. The use of MIH as prophylactic neuroprotectant in the early phase of adult TBI is not supported by clinical evidence and is not recommended.

Análisis del ciclo de vida de sistemas de tratamiento de aguas residuales: influencia de los materiales utilizados

En este proyecto se tiene como objetivo comparar una EDAR específica con otras tres, desde el punto de vista ambiental, y establecer diferentes alternativas. En particular, se ha evaluado la mejor alternativa en la obtención de energía eléctrica para la propia utilización de la planta de tratamiento de aguas residuales, a partir del biogás generado en el digestor en la línea de lodos. En este tipo de instalaciones, entre las alternativas tanto en su uso actual como en fase de desarrollo, el motor de cogeneración de electricidad y el calor es el más utilizado para obtener simultáneamente la electricidad necesaria para las instalaciones y el calor necesario para mantener el digestor de lodos a la temperatura de trabajo (36ºC aproximadamente). Las otras alternativas evaluadas en este estudio son las pilas de biogás de membrana electrolítica polimérica (en inglés Polymeric Electrolyte Membrane, PEM) y las pilas de óxidos sólidos (en inglés Solid Oxide Fuel Cells, SOFC) con una turbina de gas (sistema híbrido SOFC-GT). Por otro lado, se estudian las características de los materiales que componen los dispositivos MEC (microbial electrolysis cell) y las pilas PEM y SOFC, así como las ventajas e inconvenientes de usar estas nuevas tecnologías en el tratamiento de aguas residuales, así como la evaluación del impacto ambiental de la EDAR objeto de estudio, que se ha llevado a cabo utilizando el análisis de ciclo de vida (ACV). El ACV es una herramienta que permite comparar diferentes procesos o productos que tengan la misma función, y así evaluar la alternativa que conlleve una mejora en el medio ambiental. La metodología de ACV pretende evaluar en detalle el ciclo de vida completo de un producto o proceso. Un ACV se suele definir de tipo "cradle to grave" o "desde la cuna hasta la tumba" o bien de tipo "gate to gate", o "de puerta a puerta". En el primer caso el estudio analiza el ciclo de vida completo del sistema, dese el origen hasta el final, mientras que en el segundo caso el ACV no tiene en cuenta su disposición final (vertedero, reciclaje, etc.). Un estudio de ACV del primer tipo conlleva hacer un estudio muy detallado, que en la práctica puede resultar muy largo y laborioso por la dificultad de encontrar todos los datos necesarios. Por ello, muchos estudios de ACV que se encuentran en la literatura suelen ser del tipo "gate to gate". Además, hay que esablecer las fronteras del sistema a estudiar, ya que hay procesos que tienen muy poca contribución a las categorías de impacto ambiental. En una EDAR los principales procesos considerados en el ACV llevado a cabo son el consumo de productos químicos, de electricidad, la producción de lodos y su utilización como composta, el biogás y su utilización para producir electricidad, los residuos sólidos y las distintas emisiones al medio producidas por el propio funcionamiento de la EDAR. Las operaciones relacionadas indirectamente como el transporte de los lodos, de productos químicos, de los residuos sólidos y la infraestructura con una vida media de 30 años no influyen significativamente en los resultados, por ejemplo el transporte de los lodos con un camión a 30km contribuyen en menos de 1% en todas las categorías de impacto. De acuerdo con las normativas ISO series 14040 que regulan las pautas de un ACV, se establece una unidad funcional apropiada, o sea habitante equivalente, ya que es la más apropiada por tener en cuenta la carga contaminante en el agua a tratar, parámetro imprescindible para comparar EDARs. Redefiniendo las fronteras, se realiza un ACV del depósito del biogás sin tener en cuenta el resto de la instalación y se toma como unidad funcional m3 de biogás, en el caso concreto de obtener biogás mediante un dispositivo MEC, que maximiza la cantidad de hidrógeno en detrimento de la cantidad de metano contenido en el biogás, observándose que la contribución de un biogás con un alto contenido en hidrógeno y, por tanto bajo en metano, produce una mejora ambiental. Las categorías de impacto ambiental que tienen contribución son el calentamiento global y la oxidación fotoquímica; el dispositivo MEC hace quela contribución a estas categorías de impacto sea de un orden de magnitud inferior con respecto al biogás generado en un digestor. Además, si se produce la combustión del biogás, la única categoría de impacto que tiene contribución es la de calentamiento global; para una dispositivo MEC la contribución sigue siendo un orden de magnitud inferior con respecto al biogás de un digestor de lodos.

Phase II study of weekly plitidepsin as second-line therapy for small cell lung cancer.

OBJECTIVE: To evaluate the antitumor activity and safety profile of plitidepsin administered as a 1h weekly intravenous (i.v.) infusion of 3.2mg/m(2) to patients with small cell lung cancer (SCLC) who relapsed or progressed after one line of chemotherapy. PATIENTS AND METHODS: This was a multicenter, open-label, single-arm, exploratory, phase II clinical trial. Treatment lasted until disease progression, unacceptable toxicity, patient refusal or treatment delay for >2 weeks. Objective response rate (primary efficacy endpoint) was evaluated according to response evaluation criteria in solid tumors (RECIST). The rate of stable disease (SD) lasting for at least 6 months and time-to-event variables were secondary endpoints of efficacy. Toxicity was assessed using National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 2.0. RESULTS: Twenty pretreated SCLC patients (median age, 60 years) with extensive (n=13) or limited-stage disease (n=7) received a total of 24 treatment cycles (median, one cycle per patient; range, 1-2). Objective tumor responses were not observed and only one of the 17 evaluable patients had SD. With a median follow-up of 11.8 months, the progression-free survival and the median overall survival were 1.3 months and 4.8 months, respectively. The most troubling or common toxicities were fatigue, muscle weakness, lymphopenia, anemia (no patients showed neutropenia), and asymptomatic, non-cumulative increase of transaminases levels and alkaline phosphatase. CONCLUSION: This clinical trial shows that a cycle of 1h weekly i.v. infusion of plitidepsin (3.2mg/m(2)) was generally well tolerated other than fatigue and muscle weakness in patients with pretreated SCLC. One patient died due to multi-organ failure. The absence of antitumor activity found here precludes further studies of this plitidepsin schedule as second-line single-agent treatment of SCLC.

Preparació de puntes de tungstè per a microscòpia d'efecte túnel (STM)

Es presenten els resultats experimentals obtinguts durant l’estudi sistemàtic realitzat de la preparació electroquímica de puntes de tungstè per al Microscopi d’Efecte Túnel (STM), fent servir dos electròlits: KOH i NaOH. L’estudi sobre la morfologia, longitud de la punta i radi de curvatura de la punta en funció del voltatge aplicat i les concentracions de l’electròlit es descriu al capítol 3. La caracterització de les puntes es va dur a terme, per una part, mitjançant un microscòpic electrònic de rastreig (SEM) i per l’altre banda, amb el ús de les puntes obtingudes al STM. En resumen, els resultats mostren que ambdós electròlits permeten obtenir puntes que es poden fer servir amb èxit per l’obtenció d’imatges amb l’STM. Les millors puntes són aquelles que s’obtenen dins de rangs de concentracions d’electròlit baixes, entre valor de 10 a 15% en pes pel NaOH i entre 10 i 20% pel KOH i rangs de voltatge entre 3 a 7 V pel NaOH i 4 a 8 V pel KOH. S’observa que es requereixen temps d’atac electroquímic menors fent servir com a electròlit NaOH. S’estudia, en el capítol 4, el tractament que requereix la punta per tal d’eliminar les impureses de la seva superfície. Es realitzen diferents proves amb tres mètodes de neteja: (1) tractament químic, (2) bombardeig iònic i (3) tractament tèrmic de recuit. En el capítol 5 del projecte s’analitzen les imatges d’una mostra d’or, Au(110), d’estructura coneguda, amb el microscopi d’efecte túnel STM) del laboratori fent servir les puntes obtingudes sota les condicions considerades òptimes. El resultat confirma el bon comportament de les puntes obtingudes sota les condicions descrites en els capítols anteriors i establert una pauta a seguir per obtenir puntes d’una manera senzilla i reproduïble.

Ontogenetic changes in digestive enzymatic capacities of the spider crab, Maja brachydactyla (Decapoda: Majidae)

Ontogenetic changes in digestive capabilities were analyzed in larvae and first juveniles of the spider crab Maja brachydactyla. Activities of five proteinases (total proteases, trypsin, chymotrypsin, pepsin-like and aminopeptidase), three carbohydrases (amylase, maltase and chitinase), an esterase and an alkaline phosphatase were studied to evaluate digestive enzyme profiles of the species. Both quantitative (spectrophotometry and fluorometry) and qualitative (SDS-PAGE) approaches were used. All assayed enzymes were active from hatching (zoea I-ZI) throughout larval development and in first juveniles. Significant variations during ontogeny were found only in total activities likely as a consequence of digestive system development. Specific activity varied little over ontogeny, being significant only for chitinase. Total proteases, trypsin and pepsin-like activities showed a similar pattern of increase as larval ontogeny advanced, decreasing significantly in juveniles. Chymotrypsin continued to increase, showing maximum activity after metamorphosis. Proteinase zymograms confirmed strong proteolytic activity in first zoeas, with increasing bands over the course of ontogeny, decreasing after metamorphosis. A group of bands with high molecular mass was specific to larval stages. Amylase and maltase showed a parallel pattern of continuous increase of total activity as development advanced. Gel-SDS-PAGE showed unchanged patterns of amylase activity in first zoeas of different ages and the most complex set of bands during larval ontogeny in second zoea. Esterase total activity increased significantly as ZI's aged likely reflecting introduction of a lipid-enriched diet. The importance of lipid accumulation at the beginning of ontogeny was also confirmed by the protease/esterase and amylase/esterase activity ratios, which decreased from hatch to late ZI and might be explained as an adaptation, ensuring the next molt. The results suggest that larvae of M. brachydactyla are capable of digesting a variety of dietary substrates as soon as they hatch.

Water as an essential nutrient: the physiological basis of hydration.

How much water we really need depends on water functions and the mechanisms of daily water balance regulation. The aim of this review is to describe the physiology of water balance and consequently to highlight the new recommendations with regard to water requirements. Water has numerous roles in the human body. It acts as a building material; as a solvent, reaction medium and reactant; as a carrier for nutrients and waste products; in thermoregulation; and as a lubricant and shock absorber. The regulation of water balance is very precise, as a loss of 1% of body water is usually compensated within 24 h. Both water intake and water losses are controlled to reach water balance. Minute changes in plasma osmolarity are the main factors that trigger these homeostatic mechanisms. Healthy adults regulate water balance with precision, but young infants and elderly people are at greater risk of dehydration. Dehydration can affect consciousness and can induce speech incoherence, extremity weakness, hypotonia of ocular globes, orthostatic hypotension and tachycardia. Human water requirements are not based on a minimal intake because it might lead to a water deficit due to numerous factors that modify water needs (climate, physical activity, diet and so on). Water needs are based on experimentally derived intake levels that are expected to meet the nutritional adequacy of a healthy population. The regulation of water balance is essential for the maintenance of health and life. On an average, a sedentary adult should drink 1.5 l of water per day, as water is the only liquid nutrient that is really essential for body hydration.

Adenosine Deaminase and Guanosine Deaminase Activities in Sera of Patients with Viral Hepatitis

In order to investigate purin and primidin metabolism pathways in hepatitis, adenosine deaminase (ADA) and guanosine deaminase (GDA) activities in sera of patients with different types and manifestations of viral hepatitis disease (A, B, C, D, E, chronic, acute) were investigated and compared with the control group of healthy individuals. Hepatitis cases were classified with respect to their serological findings and clinics. When compared all the hepatitis cases with the controls, levels of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase enzymes, as well as ADA and GDA, were significantly higher than the control group (p<0.01). Levels of ADA and GDA in hepatitis cases were determined as 26.07±11.98 IU/l and 2.37±1.91 IU/l, respectively. When compared their ADA and GDA levels amongst the classified hepatitis groups, there was no difference in ADA levels amongst cases (p>0.05). However, GDA levels in hepatitis A group were closed to the controls. Increase in serum ADA activities in hepatitis forms may be dependent on and reflect the increase in phagocytic activity of macrophages and maturation of T-lymphocytes, and may be valuable in monitoring in viral hepatitis cases.

Liquid line of descent of a basanitic liquid at 1.5 GPa: Constraints for metasomatic vein formation

The metasomatism observed in the oceanic and continental lithosphere is generally interpreted to represent a continuous differentiation process forming anhydrous and hydrous veins plus a cryptic enrichment in the surrounding peridotite. In order to constrain the mechanisms of vein formation and potentially clarify the nature and origin of the initial metasomatic agent, we performed a series of high-pressure experiments simulating the liquid line of descent of a basanitic magma differentiating within continental or mature oceanic lithosphere. This series of experiments has been conducted in an end-loaded piston cylinder apparatus starting from an initial hydrous ne-normative basanite at 1.5 GPa and temperature varying between 1,250 and 980°C. Near-pure fractional crystallization process was achieved in a stepwise manner in 30°C temperature steps and starting compositions corresponding to the liquid composition of the previous, higher-temperature glass composition. Liquids evolve progressively from basanite to peralkaline, aluminum-rich compositions without significant SiO2 variation. The resulting cumulates are characterized by an anhydrous clinopyroxene + olivine assemblage at high temperature (1,250-1,160°C), while at lower temperature (1,130-980°C), hydrous cumulates with dominantly amphibole + minor clinopyroxene, spinel, ilmenite, titanomagnetite and apatite (1,130-980°C) are formed. This new data set supports the interpretation that anhydrous and hydrous metasomatic veins could be produced during continuous differentiation processes of primary, hydrous alkaline magmas at high pressure. However, the comparison between the cumulates generated by the fractional crystallization from an initial ne-normative liquid or from hy-normative initial compositions (hawaiite or picrobasalt) indicates that for all hydrous liquids, the different phases formed upon differentiation are mostly similar even though the proportions of hydrous versus anhydrous minerals could vary significantly. This suggests that the formation of amphibole-bearing metasomatic veins observed in the lithospheric mantle could be linked to the differentiation of initial liquids ranging from ne-normative to hy-normative in composition. The present study does not resolve the question whether the metasomatism observed in lithospheric mantle is a precursor or a consequence of alkaline magmatism; however, it confirms that the percolation and differentiation of a liquid produced by a low degree of partial melting of a source similar or slightly more enriched than depleted MORB mantle could generate hydrous metasomatic veins interpreted as a potential source for alkaline magmatism by various authors.

Proteolytic processing of the Cyt1Ab1 toxin produced by Bacillus thuringiensis subsp. medellin

Bacillus thuringiensis produces d-endotoxins that require proteolytic processing to become active. The activation of the B. thuringiensis subsp. medellin 28 kDa (Cyt1Ab1) cytolytic toxin by trypsin, chymotrypsin and gut extract from Culex quinquefasciatus larvae was analyzed. The Cyt1Ab1 toxin of B. thuringiensis subsp. medellin was processed by all proteases tested to fragments between 23 and 25 kDa, while processing of the Cyt1Aa1 toxin produce fragments between 22.5 and 24.5 kDa. The Cyt1Ab1 toxin was preferentially processed at the alkaline pH of 12. The in vitro proteolytic processing of the Cyt1Ab1 toxin by C. quinquefasciatus larvae midgut extract showed a 25 kDa fragment; a similar result was observed when the activation was performed in the in vivo experiments. The solubilized Cyt1Ab1 toxin and the protease resistant cores generated by in vitro processing showed hemolytic activity but not mosquitocidal activity. Amino terminal sequence of the C. quinquefasciatus gut extract resistant fragment indicated that the cutting site was located between Lys31 and Asp32, with a sequence DDPNEKNNHNS; while for the trypsin-resistant fragment the cutting site was determined between Leu29 and Arg30, and for the chymotrypsin-resistant fragment between Arg30 and Lys31.