Resumen Este trabajo abarcó el estudio sedimentológico, paleontológico y geoquímico de la Formación La Luna, en una localidad al oeste del Macizo de Santander (Matanza, Colombia). La sección corresponde a un corte de 42 metros, compuesto por una alternancia de mudstones y wackestones inter- estratificados, niveles de chert, fosforitas y bentonitas. El contenido fósil está conformado por restos de amonitas, inocerámidos, gasterópodos turritélidos, fragmentos de peces y foraminíferos planctónicos. La asociación fósil indica una edad de Coniaciano-Santoniano. Las características sedimentológicas, el tipo de fósiles encontrados y los análisis petrográficos/geoquímicos desarrollados en esta sección sugieren condiciones de depositación en plataforma externa y una baja oxigenación en los sedimentos de fondo. Las conclusiones de este trabajo coinciden con interpretaciones preexistentes de la región cuenca, sugiriendo relaciones litoestratigráficas con la sucesión sedimentaria del Valle Medio del Magdalena (parte superior del “Miembro Galembo”). Sin embargo, solo estudios estratigráficos detallados en esta parte del Macizo de Santander, permitirán entender su evolución geológica durante el Cretácico superior.

Abstract This study comprised the sedimentological, paleontological and geochemical survey of the La Luna Formation, using as a reference one section in the west flank of the Santander Massif (Matanza, Colombia). The 42-meter length section comprises an alternance of interstratified mudstones, wackestones, chert, phosphorite and bentonite levels. Fossil content is defined by rest of ammonoids, inoceramids, turritellid gastropods, fish remains and planktonic foraminifers, suggesting all a Coniacian-Santonian age. The facial analysis, the fossil content and preliminary petrographic/geochemical analysis also suggest an outer shelf setting and low oxygenation conditions in the bottom sediments. In general, our results agree with previous interpretations of La Luna Formation, suggesting a closer relation with the Upper Cretaceous succession of the Middle Magdalena (upper “Galembo Member”). However, only detailed stratigraphical studies in this part of the Santander Massif, will allow a better understanding of its geological evolution during the Late Cretaceous.

BACKGROUND The inappropriate use of antibiotics has led to the accelerated growth of resistance to antibiotics. The search for new therapeutic strategies (i.e., antimicrobial peptides-AMPs) has thus become a pressing need. OBJECTIVE Characterising and evaluating Sarconesiopsis magellanica larval fat body-derived AMPs. METHODS Fat body extracts were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC); mass spectrometry was used for characterising the primary structure of the AMPs so found. ProtParam (Expasy) was used for analysing the AMPs’ physico-chemical properties. Synthetic AMPs’ antibacterial activity was evaluated. FINDINGS Four new AMPs were obtained and called sarconesin III, IV, V and VI. Sarconesin III had an α-helix structure and sarconesins IV, V and VI had linear formations. Oligomer prediction highlighted peptide-peptide interactions, suggesting that sarconesins III, V and VI could form self-aggregations when in contact with the microbial membrane. AMPs synthesised from their native molecules’ sequences had potent activity against Gram-positive bacteria and, to a lesser extent, against Gram-negative and drug-resistant bacteria. Sarconesin VI was the most efficient AMP. None of the four synthetic AMPs had a cytotoxic effect. MAIN CONCLUSIONS S. magellanica larval fat body-derived antimicrobial peptides are an important source of AMPs and could be used in different antimicrobial therapies and overcoming bacterial resistance.

Resumen Se presentan los resultados del proyecto de investigación Balance de la enseñanza de la filosofía en Colombia entre práctica y experiencia, a partir de problematizaciones epistemológicas que delimitan el objeto de la didáctica general y del encuentro con el emergente conocimiento didáctico del contenido [CDC], que plantea la necesidad de configurar una didáctica de la filosofía y sus conceptualizaciones. Se utiliza el modelo de Park y Oliver para analizar el CDC en clases de filosofía. La intención es valorar la pertinencia de este modelo en la enseñanza de la filosofía y encontrar potencialidades y limitaciones al ejecutar un modelo que evidencie el saber filosófico que circula en los espacios y tiempos de formación, lo cual permite reconsiderar el modelo mismo y modificarlo en función de la filosofía como un campo de saber escolarizado.

Abstract The results of the research project Assessment of the teaching of philosophy in Colombia between practice and experience are presented, based on epistemological problematizations that delimit the object of general didactics and on the encounter with the emerging pedagogical content knowledge [PCK], which raises the need to configure the didactics of philosophy and its conceptualizations. Park and Oliver's model is used to analyze the PCK in philosophy classes. The intention is to assess the pertinence of this model in the teaching of philosophy and to find potentialities and limitations when executing a model that highlights the philosophical knowledge that exists in spaces and times of formation, which allows reconsidering the model itself and modifying it in order to make it a field of schooled knowledge.

Resumo Apresentam-se os resultados do projeto de investigação Balance do ensino da filosofia na Colômbia entre a prática e a experiência, com base em problemas epistemológicos que delimitam o objeto da didática geral e o encontro com o emergente conhecimento didático do conteúdo [CDC], o que suscita a necessidade de configurar uma didática da filosofia e suas conceptualizações. O modelo de Park e Oliver sado para analisar o CDC nas aulas de filosofia. A intenção é avaliar a relevância deste modelo no ensino da filosofia e encontrar potencialidades e limitações ao executar um modelo que mostre o conhecimento filosófico que circula nos espaços e tempos de formação, o que permite reconsiderar o modelo mesmo e modificá-lo de acordo com a filosofia como um campo académico do conhecimento.

The goal of this study was to demonstrate the usefulness of an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of pulmonary tuberculosis (PTB) and extrapulmonary TB (EPTB). This assay used 20 amino acid-long, non-overlapped synthetic peptides that spanned the complete Mycobacterium tuberculosis ESAT-6 and Ag85A sequences. The validation cohort consisted of 1,102 individuals who were grouped into the following five diagnostic groups: 455 patients with PTB, 60 patients with EPTB, 40 individuals with non-EPTB, 33 individuals with leprosy and 514 healthy controls. For the PTB group, two ESAT-6 peptides (12033 and 12034) had the highest sensitivity levels of 96.9% and 96.2%, respectively, and an Ag85A-peptide (29878) was the most specific (97.4%) in the PTB groups. For the EPTB group, two Ag85A peptides (11005 and 11006) were observed to have a sensitivity of 98.3% and an Ag85A-peptide (29878) was also the most specific (96.4%). When combinations of peptides were used, such as 12033 and 12034 or 11005 and 11006, 99.5% and 100% sensitivities in the PTB and EPTB groups were observed, respectively. In conclusion, for a cohort that consists entirely of individuals from Venezuela, a multi-antigen immunoassay using highly sensitive ESAT-6 and Ag85A peptides alone and in combination could be used to more rapidly diagnose PTB and EPTB infection.

El interés en el uso de péptidos antimicrobianos para el control de enfermedades de hongos en plantas de banano ha aumentado en los últimos años. En este trabajo se analizó la actividad antifúngica de diferentes péptidos sobre el desarrollo in vitro de Mycosphaerella fijiensis y se encontró que estos inhiben el crecimiento micelial del hongo y la germinación de sus ascosporas. Todos los péptidos evaluados mostraron actividad contra el hongo, aunque con marcadas diferencias en los valores de IC50 los cuales variaron entre 3,06 y 239,61 µg/mL. Los péptidos que presentaron mayor actividad fueron los designados Ib-AMP4 e Ib-AMP2, ambos derivados de la planta Impatiens balsamina. De otro lado, la actividad in vitro de estos péptidos parece ser compatible con algunos fungicidas químicos ya que cuando se usaron en forma combinada, no se encontraron efectos antagónicos o sinérgicos con estos agentes. Los hallazgos sugieren que los péptidos antimicrobianos podrían ser utilizados como posibles estrategias alternativas para el control de la Sigatoka negra.

The interest in the use of antimicrobial peptides to control fungal diseases in banana plants has been rising in the last years. In this paper we analyzed the antifungal activity of different peptides on the in vitro development of Mycosphaerella fijiensis and found that they inhibited fungal mycelial growth and ascospore germination. All peptides evaluated displayed activity against the fungus although with marked differences in IC50 values ranging between 3.06 and 239.61 µg/mL. The peptides exhibiting better activity were the designated peptides Ib-AMP4 and Ib-AMP2, both derived from Impatiens balsamina. Furthermore, the in vitro activity of these peptides seemed compatible with existing chemical fungicides, having no antagonistic or synergistic effect with these agents. The effect of these peptides on M. fijiensis mycelial elongation and ascospores germination suggests that they can be used as potential alternative strategies for the control of black Sigatoka disease.

In this study, the use of Mtp-40 and alpha antigen polymerase chain reaction (PCR) amplification fragments for the precise tuberculosis (TB) diagnosis was evaluated. One hundred and ninety two different samples were obtained from 113 patients with suspected TB. Mtp-40 and alpha antigen protein genes were amplified by the PCR technique and compared to both the "gold standard" (culture) test, as well as the clinical parameters (including a clinical record and X-ray film exam in 113 patients). Thirty-eight of the 113 patients had a presumptive clinical diagnosis of TB; 74% being detected by PCR technique, 58% by culture and 44% by direct microscopic visualization. Weconclude that it is possible to use PCR as a suitable technique for the detection of any mycobacteria by means of the alpha antigen product, or the specific infection of Mycobacterium tuberculosis by means of the mtp-40 gene. This might be a good supporting tool in difficult clinical TB diagnosis and pauci-bacillary cases.

Differential display technique was applied in order to identify transcripts which are present in axenic amastigotes but not in promastigotes of the Leishmania panamensis parasites. One of them was cloned and the sequence reveals an open reading frame of 364 amino acids (aprox. 40 kDa). The deduced protein is homologous to the serine/threonine protein kinases and specially to the mitogen activates protein kinases from eukaryotic species. Southern blot analysis suggest that this transcript, named lpmkh, is present in the genome of the parasite as a single copy gene. These results could imply that lpmkh could be involved in the differentiation process or the preservation of amastigotes in axenic conditions.

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.

The malarial GBP 130 protein binds weakly to intact human erythrocytes; the binding sites seem to be located in the repeat region and this region's antibodies block the merozoite invasion. A peptide from this region (residues from 701 to 720) which binds to human erythrocytes was identified. This peptide named 2220 did not bind to sialic acid; the binding site on human erythrocyte was affected by treatment with trypsin but not by chymotrypsin. The peptide was able to inhibit Plasmodium falciparum merozoite invasion of erythrocytes. The residues F701, K703, L705, T706, E713 (FYKILTNTDPNDEVERDNAD) were found to be critical for peptide binding to erythrocytes.