Orthopedic implications of the corona mortis: a case report / Implicaciones ortopédicas de la corona mortis: reporte de un caso

SUMMARY: Corona mortis is classified as a connection between the inferior epigastric and obturator vessels over the superior pubic ramus. Its incidence varies among different studies. The corona mortis is an extremely important anatomical variation as it can be injured in a great number of procedures. Moreover, it can also be injured during pelvic or acetabular fractures. A male cadaver fixed in a 10 % formalin solution had its pelvic region dissected and an arterial corona mortis was observed on its right side. The left hemipelvis presented no variations whatsoever. This vessel was measured with the aid of a digital caliper. We aim to report this variation and address - from an orthopedic point of view - the clinical and surgical significance of the corona mortis.

RESUMEN: La corona mortis es clasificada como una conexión entre los vasos epigástricos inferiores y obturadores sobre la rama superior del pubis. Su incidencia varía según los diferentes estudios. La corona mortis es una variación anatómica extremadamente importante, ya que se es posible dañarla en un número significativo de procedimientos. Además, también puede resultar lesionada durante las fracturas pélvicas o acetabulares. Durante la disección de un cadáver de sexo masculino fijado en solución de formalina al 10 %, se observó la corona mortis arterial en el lado derecho de la región pélvica. El lado izquierdo de la pelvis no presentó ninguna variación. Se midió la corona mortis con ayuda de un calibre digital. Nuestro objetivo fue informar sobre esta variación y abordar - desde el punto de vista ortopédico - la importancia clínica y quirúrgica de la corona mortis.

High-performance variants of plant diacylglycerol acyltransferase 1 generated by directed evolution provide insights into structure function.

Diacylglycerol acyltransferase 1 (DGAT1) catalyzes the acyl-CoA-dependent biosynthesis of triacylglycerol, the predominant component of seed oil. In some oil crops, including Brassica napus, the level of DGAT1 activity can have a substantial effect on triacylglycerol production. Structure-function insights into DGAT1, however, remain limited because of the lack of a three-dimensional detailed structure for this membrane-bound enzyme. In this study, the amino acid residues governing B. napus DGAT1 (BnaDGAT1) activity were investigated via directed evolution, targeted mutagenesis, in vitro enzymatic assay, topological analysis, and transient expression of cDNA encoding selected enzyme variants in Nicotiana benthamiana. Directed evolution revealed that numerous amino acid residues were associated with increased BnaDGAT1 activity, and 67% of these residues were conserved among plant DGAT1s. The identified amino acid residue substitution sites occur throughout the BnaDGAT1 polypeptide, with 89% of the substitutions located outside the putative substrate binding or active sites. In addition, cDNAs encoding variants I447F or L441P were transiently overexpressed in N. benthamiana leaves, resulting in 33.2 or 70.5% higher triacylglycerol content, respectively, compared with native BnaDGAT1. Overall, the results provide novel insights into amino acid residues underlying plant DGAT1 function and performance-enhanced BnaDGAT1 variants for increasing vegetable oil production.

Maternal malnutrition diet during lactation period leads to incomplete catch-up growth in femur of the pups at adulthood / Restricción alimentaria materna durante la lactancia conduce a la recuperación del crecimiento incompleto en el fémur de las crías en la edad adulta

The aim of this study was to evaluate the effects of maternal protein and energy restriction during lactation, analyzing on morphological dimensions whether there was catch-up growth through normative nutrition restored, as well as on mechanical axis of femur of the offspring at adulthood. At parturition, Wistar rat dams were randomly assigned to the following groups: 1) control group (C) - free access to a standard laboratory diet containing 23 % protein, 2) protein-energy restricted group (PER) - free access to an isoenergetic, protein-restricted diet containing 8 % protein, and 3) energy-restricted group (ER) ­ fed with restricted amounts of a standard laboratory diet. At weaning, all pups were separated of dams and received free access to a standard laboratory diet containing 23 % protein until 180 days, when the rats were anesthetized and sacrificed. The dimensions of excised pup femur were measured directly using pre-established anatomical points. Morphometric analysis of the femur (macroscopic) showed that most of the measurements in the ER and PER groups were significantly lower than in the control group, with the greatest reductions occurring in the PER group and several structural abnormalities. Our results show that protein and energy restriction during lactation leads to an incomplete catch-up growth in adulthood. The femur showed significant reduction in most of the parameters in the two treated groups, particularly the PER group, when compared to the control group.

El objetivo de este estudio fue evaluar los efectos de la restricción de la proteína materna y de energía durante la lactancia, y analizar las dimensiones morfológicas si hubo recuperación del crecimiento a través de la nutrición normativa restaurada, así como en el eje mecánico del fémur de la descendencia en la edad adulta. En el parto, las crías de ratas Wistar fueron agrupadas aleatoriamente en los siguientes grupos: 1) control (C) - con acceso libre a una dieta estándar del laboratorio, que contenía 23 % de proteínas; 2) con restricción de proteínas y energía (PER) - acceso libre a una dieta isoenergética, con restricción de proteínas, conteniendo un 8 % de éstas y 3) grupo con restricción de energía, alimentado con restricción en la cantidad de alimento de la dieta estándar del laboratorio (ER). Al destete, todas las crías fueron separadas y recibieron las dietas establecidas hasta los 180 días (d180), luego fueron anestesiadas y sacrificadas. Las mediciones de los fémures de las crías de rata fueron obtenidas por puntos anatómicos preestablecidos. El análisis morfométrico de fémur demostró que la mayoría de las mediciones en los grupos ER y PER eran significativamente menores que las del grupo control, con mayores reducciones en el grupo PER. Nuestros resultados muestran que las restricciones de energía y proteínas durante la lactancia conducen a una recuperación del crecimiento incompleto en la edad adulta. El fémur mostró una reducción significativa en la mayoría de los parámetros en los dos grupos tratados, en particular el grupo de PER, en comparación con el grupo control.

Clinical practice guide for the choice of perioperative volume-restoring fluid in adult patients undergoing non-cardiac surgery.

The present Clinical practice guide responds to the clinical questions about security in the choice of fluid (crystalloid, colloid or hydroxyethyl starch 130) in patients who require volume replacement during perioperative period of non-cardiac surgeries. From the evidence summary, recommendations were made following the GRADE methodology. In this population fluid therapy based on crystalloids is suggested (weak recommendation, low quality evidence). In the events where volume replacement is not reached with crystalloids, the use of synthetic colloids (hydroxyethyl starch 130 or modified fluid gelatin) is suggested instead of 5% albumin (weak recommendation, low quality evidence). The choice and dosage of the colloid should be based in the product characteristics, patient comorbidity and anesthesiologist's experience.

Heterologous expression of flax PHOSPHOLIPID:DIACYLGLYCEROL CHOLINEPHOSPHOTRANSFERASE (PDCT) increases polyunsaturated fatty acid content in yeast and Arabidopsis seeds.

BACKGROUND: Flax (Linum usitatissimum L.) is an agriculturally important crop with seed oil enriched in α-linolenic acid (18:3 (cisΔ9, 12, 15); ALA). This polyunsaturated fatty acid (PUFA) is the major determinant for the quality of flax seed oil in food, nutraceuticals and industrial applications. The recently identified enzyme: phosphatidylcholine diacylglycerol cholinephosphotransferase (PDCT), catalyzes the interconversion between phosphatidylcholine (PC) and diacylglycerol (DAG), and has been shown to play an important role in PUFA accumulation in Arabidopsis thaliana seeds. METHODS: Two flax PDCT genes were identified using homology-based approach. RESULTS: In this study, we describe the isolation and characterization of two PDCT genes from flax (LuPDCT1 and LuPDCT2) with very high nucleotide sequence identity (97%) whose deduced amino acid sequences exhibited approximately 55% identity with that of A. thaliana PDCT (AtROD1). The genes encoded functionally active enzymes that were strongly expressed in developing embryos. Complementation studies with the A. thaliana rod1 mutant demonstrated that the flax PDCTs were capable of restoring PUFA levels in planta. Furthermore, PUFA levels increased in Saccharomyces cerevisiae when the flax PDCTs were co-expressed with FATTY ACID DESATURASES (FADs), FAD2 and FAD3, while seed-specific expression of LuPDCT1 and LuPDCT2 in A. thaliana resulted in 16.4% and 19.7% increases in C18-PUFAs, respectively, with a concomitant decrease in the proportion of oleic acid (18:1 (cisΔ9); OA). CONCLUSIONS: The two novel PDCT homologs from flax are capable of increasing C18-PUFA levels substantially in metabolically engineered yeast and transgenic A. thaliana seeds. These flax PDCT proteins appear to play an important dual role in the determination of PUFA content by efficiently channelling monounsaturated FAs into PC for desaturation and moving the resulting PUFAs out of PC for subsequent use in TAG synthesis. These results indicate that flax PDCTs would be useful for bioengineering of oil crops to increase PUFA levels for applications in human food and nutritional supplements, animal feed and industrial bioproducts.

Frequency of sternal foramen evaluated by MDCT: a minor variation of great relevance.

Due to inadvertent cardiac or great vessel injury, sternal foramina may pose as a great hazard during sternal puncture. They can also be misinterpreted as osteolytic lesions in cross-sectional imaging of the sternum. The distribution of these variations differs between populations, but data from Brazilians are scarcely reported. Therefore, this study aimed to verify the frequency of midline sternal foramen and double-ended xiphoid process, as developmental variations, in order to avoid fatal complications following sternal puncture of sternal acupuncture treatment. A total of 114 chest computed tomograms were evaluated. The frequency of midline sternal foramen in a complication risk bearing feature is of approximately 10.5%. The double-ended xiphoid process was present in 17.5%. We conclude that sternal acupuncture should be planned in the region of corpus-previous CT should be done to rule out this variation. Furthermore, we strongly recommend the acupuncture technique which prescribes a safe superficial-oblique approach to the sternum.

Bilateral absence of superior gemellus muscle in elderly cadaver / Ausencia bilateral del músculo gemelo superior en un cadáver anciano

The superior gemellus muscle (SGM) normally arises from the outer surface of the spine of the ischium, blends with the upper part of the tendon of the obturator internus, and is inserted with it into the medial surface of the greater trochanter. In this paper, we describe an anatomical variation in which the SGM is absent bilaterally. Therefore, as there are not many cases in literature, our attention has been drawn to the importance about absence of SGM, in order to improve anatomical and clinical knowledge about this finding.

El músculo gemelo superior (SGM) que se origina de la superficie externa de la parte posterior del isquion, se une a la parte superior del tendón del músculo obturador interno, y se introduce con él en la superficie medial del trocánter mayor. En este trabajo se describe una variación anatómica en la que el SGM está ausente bilateralmente. Debido a la escaza descripción de esta variación, es relevante conocer la ausencia de la SGM, con el fin de mejorar el conocimiento anatómico y clínico de este hallazgo.

Identification of a pair of phospholipid:diacylglycerol acyltransferases from developing flax (Linum usitatissimum L.) seed catalyzing the selective production of trilinolenin.

The oil from flax (Linum usitatissimum L.) has high amounts of α-linolenic acid (ALA; 18:3(cis)(Δ9,12,15)) and is one of the richest sources of omega-3 polyunsaturated fatty acids (ω-3-PUFAs). To produce ∼57% ALA in triacylglycerol (TAG), it is likely that flax contains enzymes that can efficiently transfer ALA to TAG. To test this hypothesis, we conducted a systematic characterization of TAG-synthesizing enzymes from flax. We identified several genes encoding acyl-CoA:diacylglycerol acyltransferases (DGATs) and phospholipid:diacylglycerol acyltransferases (PDATs) from the flax genome database. Due to recent genome duplication, duplicated gene pairs have been identified for all genes except DGAT2-2. Analysis of gene expression indicated that two DGAT1, two DGAT2, and four PDAT genes were preferentially expressed in flax embryos. Yeast functional analysis showed that DGAT1, DGAT2, and two PDAT enzymes restored TAG synthesis when produced recombinantly in yeast H1246 strain. The activity of particular PDAT enzymes (LuPDAT1 and LuPDAT2) was stimulated by the presence of ALA. Further seed-specific expression of flax genes in Arabidopsis thaliana indicated that DGAT1, PDAT1, and PDAT2 had significant effects on seed oil phenotype. Overall, this study indicated the existence of unique PDAT enzymes from flax that are able to preferentially catalyze the synthesis of TAG containing ALA acyl moieties. The identified LuPDATs may have practical applications for increasing the accumulation of ALA and other polyunsaturated fatty acids in oilseeds for food and industrial applications.

High prevalence of sternal foramen: quantitative, anatomical analysis and its clinical implications in acupuncture practice / Alta prevalencia del foramen esternal: análisis cuantitativo y anatómico y sus implicancias clínicas en la práctica de la acupuntura

The aim of our study was to verify the prevalence of the sternal foramen in adult cadavers and dry bones, as well as to determine its exact localization and relation to acupuncture points. One hundred eighty sternums fixed and contained in 10 percent formaldehyde solution were examined, of which 100 were dry bones and 80 belonged to adult cadavers. The morphometric measures were expressed in millimeters when measuring the length: 1) from jugular incision to the foramen (JI-F); 2) from sternal angle to the foramen (EA-F); 3) from xiphoid process to the foramen (XP-F). Statistical analysis was performed to compare expected vs obtained foramina frequency, using Fisher's test (p0.05 was considered significant). The results showed 16.6 percent sternal foramina, significant higher than expected (p0.0248). Of the 30 foramina, 53.3 percent were found in cadavers, of which one was a woman, and 46.7 percent sternums were found in dry bones. Of the cadavers with sternal foramen, 10 foramina were at the 5th sternochondral articulation level and 6 foramina at the 4th sternochondral level. Of the 14 analyzed dry bones, 9 foramina were at the space between the 4th and the 5th costal pit level and 5 foramina were at the 5th costal pit level. The mean±SD (mm) total length of the sternums was 151.8+/-34 and the measures JI-F, EA-F, and XP-F were, respectively, 103.8+/-22.1mm, 65.6+/-15mm and 46.9 +/-15mm. Knowledge of this occurrence is important to avoid serious heart injury by needle insertion, especially as this area holds a commonly used acupuncture point and sternal puncture...

El objetivo del estudio fue verificar la prevalencia del foramen esternal en cadáveres adultos y huesos secos, así como, determinar su localización y su relación con los puntos de acupuntura. Fueron examinados 180 esternones fijados en solución de formol al 10 por ciento, 100 eran huesos secos y 80 pertenecían a cadáveres de individuos adultos. Las medidas morfométricas se expresaron en milímetros, efectuándose las siguientes mediciones: 1) desde la incisura yugular al foramen; 2) desde el ángulo esternal al foramen y 3) desde el proceso xifoides hasta al foramen. El análisis estadístico permitió comparar la frecuencia de los forámenes, usando el test de Fisher (p 0,05 ). Los resultados mostraron la presencia del foramen esternal en 16,6 por ciento de los casos, siendo significativamente mayor a lo esperado (p 0,0248). De los 30 forámenes, el 53,3 por ciento se encontró en cadáveres y en el 46,7 por ciento en los huesos secos. De los cadáveres con foramen esternal, 10 forámenes se encontraban a nivel de la 5 articulación esternocondral y 6 a nivel de la 4 articulación esternocondral. De los 14 forámenes de los huesos secos, 9 forámenes se encontraban entre entre el 4 y el 5 espacio intercostal y 5 se localizaban a nivel del 5 articulación. La longitud total del esternón fue 151,8 mm +/- 34 y las medidas desde la incisura yugular al foramen, desde el ángulo esternal al foramen y desde el proceso xifoides hasta al foramen fueron, 103,8 +/- 22,1 mm, 65,6 +/- 15 mm y 46,9 +/- 15 mm, respectivamente. El conocimiento de este hecho es importante para evitar la lesión cardiaca grave por la inserción de agujas, ya que esta zona tiene un punto de acupuntura de uso común en la punción esternal...

Acyl-CoA:diacylglycerol acyltransferase: molecular biology, biochemistry and biotechnology.

Triacylglycerol (TG) is a storage lipid which serves as an energy reservoir and a source of signalling molecules and substrates for membrane biogenesis. TG is essential for many physiological processes and its metabolism is widely conserved in nature. Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the final step in the sn-glycerol-3-phosphate pathway leading to TG. DGAT activity resides mainly in two distinct membrane bound polypeptides, known as DGAT1 and DGAT2 which have been identified in numerous organisms. In addition, a few other enzymes also hold DGAT activity, including the DGAT-related acyl-CoA:monoacylglycerol acyltransferases (MGAT). Progress on understanding structure/function in DGATs has been limited by the lack of detailed three-dimensional structural information due to the hydrophobic properties of theses enzymes and difficulties associated with purification. This review examines several aspects of DGAT and MGAT genes and enzymes, including current knowledge on their gene structure, expression pattern, biochemical properties, membrane topology, functional motifs and subcellular localization. Recent progress in probing structural and functional aspects of DGAT1 and DGAT2, using a combination of molecular and biochemical techniques, is emphasized. Biotechnological applications involving DGAT enzymes ranging from obesity therapeutics to oilseed engineering are also discussed.

Proximal isovelocity surface area variability during systole in dogs with mitral valve prolapse.

The proximal isovelocity surface area (PISA) principles and methodology have been described in human and veterinary medicine with special emphasis given to the ease and speed for the quantification of mitral regurgitation. Although limitations have been described in both human and veterinary medicine, in the case of veterinary medicine, clinical examples have not been well defined and in some cases have not been individually presented. The objective of this paper is to illustrate in a qualitative manner the echocardiographic existence of the dynamic behavior and variability of mitral regurgitation in dogs with mitral valve prolapse, a factor to be taken into consideration as a limitation inherent to the PISA technique.

Entrapment of the sural nerve on gastrocnemius muscle: histological analysis / Compresión del nervio sural en el músculo gastrocnemio: análisis histológico

Anatomical variations in the formation of the sural nerve are common, although the topographical localization of this nerve is constant. In this report, we describe the histological analysis of anomalous course of the medial sural cutaneous nerve which descended through the gastrocnemius via a tunnel formed within the muscle and fascia. This anatomical curiosity are clinically important when evaluating sensory axonal loss in distal axonal neuropathies since sural nerve mononeuropathy is less likely to occur.

Las variaciones anatómicas en la formación del nervio sural son comunes, aunque la localización topográfica de este nervio es constante. En este reporte se describe el análisis histológico del nervio cutáneo sural medial de curso anómalo, que descendió a través de los músculos gastrognemios en un túnel formado en el músculo y la fascia. Esta curiosidad anatómica es de importancia clínica cuando se evalúa la pérdida sensitiva distal en neuropatías axonales, desde mononeuropatía del nervio sural a otras de menor frecuencia.

Functional and topological analysis of yeast acyl-CoA:diacylglycerol acyltransferase 2, an endoplasmic reticulum enzyme essential for triacylglycerol biosynthesis.

Acyl-CoA:diacylglycerol acyltransferase (EC 2.3.1.20) is a membrane protein present mainly in the endoplasmic reticulum. It catalyzes the final and committed step in the biosynthesis of triacylglycerol, which is the principal repository of fatty acids for energy utilization and membrane formation. Two distinct family members of acyl-CoA:diacylglycerol acyltransferase, known as DGAT1 and DGAT2, have been characterized in different organisms, including mammals, fungi, and plants. In this study, we characterized the functional role and topological orientation of signature motifs in yeast (Saccharomyces cerevisiae) DGAT2 using mutagenesis in conjunction with chemical modification. Our data provide evidence that both the N and C termini are oriented toward the cytosol and have different catalytic roles. A highly conserved motif, (129)YFP(131), and a hydrophilic segment exclusive to yeast DGAT2 reside in a long endoplasmic reticulum luminal loop following the first transmembrane domain and play an essential role in enzyme catalysis. In addition, the strongly conserved His(195) within the motif HPHG, which may play a role in the active site of DGAT2, is likely embedded in the membrane. These results indicate some similarities to the topology model of murine DGAT2 but also reveal striking differences suggesting that the topological organization of DGAT2 is not ubiquitously conserved.

Lipins from plants are phosphatidate phosphatases that restore lipid synthesis in a pah1Δ mutant strain of Saccharomyces cerevisiae.

The identification of the yeast phosphatidate phosphohydrolase (PAH1) gene encoding an enzyme with phosphatidate phosphatase (PAP; 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) activity led to the discovery of mammalian Lipins and subsequently to homologous genes from plants. In the present study, we describe the functional characterization of Arabidopsis and Brassica napus homologs of PAH1. Recombinant expression studies confirmed that homologous PAHs from plants can rescue different phenotypes exhibited by the yeast pah1Δ strain, such as temperature growth sensitivity and atypical neutral lipid composition. Using this expression system, we examined the role of the putative catalytic motif DXDXT and other conserved residues by mutational analysis. Mutants within the carboxy-terminal lipin domain displayed significantly decreased PAP activity, which was reflected by their limited ability to complement different phenotypes of pah1Δ. Subcellular localization studies using a green fluorescent protein fusion protein showed that Arabidopsis PAH1 is mostly present in the cytoplasm of yeast cells. However, upon oleic acid stimulation, green fluorescent protein fluorescence was predominantly found in the nucleus, suggesting that plant PAH1 might be involved in the transcriptional regulation of gene expression. In addition, we demonstrate that mutation of conserved residues that are essential for the PAP activity of the Arabidopsis PAH1 enzyme did not impair its nuclear localization in response to oleic acid. In conclusion, the present study provides evidence that Arabidopsis and B. napus PAHs restore lipid synthesis in yeast and that DXDXT is a functional enzymic motif within plant PAHs.

Role of cysteine residues in thiol modification of acyl-CoA:diacylglycerol acyltransferase 2 from yeast.

Acyl-CoA:diacylglycerol acyltransferase (EC 2.3.1.20, DGAT or DAGAT), which catalyzes the final step in triacylglycerol biosynthesis, has at least two discrete family members (DGAT1 and DGAT2) with different physiological roles. Here we report a systematic study of the local functional and structural role of seven cysteine residues present in DGAT2 from Saccharomyces cerevisiae (ScDGAT2, also known as Dga1p) using chemical modification in combination with site-directed mutagenesis. We demonstrate that although DGAT2 was susceptible to various thiol-modifying reagents, none of the cysteines were directly involved in the catalytic activity. Analysis of the accessibility of the sulfhydryl groups revealed that cysteines are also not involved in formation of intramolecular disulfide linkages. Inhibition of DGAT activity with thiol-specific reagents was localized to cysteine 314, which was found to be in the proximity of a highly conserved motif of DGAT2. Our work indicates that although this cysteine does not play a role in enzymatic catalysis, it may reside in a crucial position that is near a possible active site of DGAT2 or related to proper folding of the protein.

Simple methods to detect triacylglycerol biosynthesis in a yeast-based recombinant system.

Standard methods to quantify the activity of triacylglycerol (TAG) synthesizing enzymes DGAT and PDAT (TAG-SE) require a sensitive but rather arduous laboratory assay based on radio-labeled substrates. Here we describe two straightforward methods to detect TAG production in baker's yeast Saccharomyces cerevisiae. First we demonstrate that a quadruple knockout yeast strain deficient in storage lipids has a reduced growth rate in a medium supplemented with fatty acids. This phenotype is rescued by restoring TAG biosynthesis and can be thus used to select yeast cells expressing a recombinant TAG-SE. In the second method, the activity of the recombinant enzyme is measured in a fluorescent in situ assay using Nile red dye that is specific for neutral lipids. Correlation between Nile red fluorescence and enzyme activity is demonstrated with several mutants of a TAG synthesizing enzyme. This yeast live-cell-based assay is rapid, inexpensive, sensitive, and is amenable to high-throughput applications. The methods can be used for a variety of applications such as isolation of novel genes, directed evolution, gene-specific drug screening and will facilitate novel approaches in the research of TAG-SE.

Antisense suppression of type 1 diacylglycerol acyltransferase adversely affects plant development in Brassica napus.

Diacylglycerol acyltransferase (DGAT) catalyzes the acyl-coenzyme A (CoA) dependent acylation of sn-1,2-diacylglycerol to form triacylglycerol in the terminal step of seed oil formation. Previous work has suggested that the level of DGAT activity may have a substantial effect on the flow of carbon into triacylglycerol, implying that the enzyme may represent a promising target for seed oil modification through biotechnological approaches. In the current study, Brassica napus DH12075 was transformed with an antisense type 1 DGAT construct, resulting in a reduction in DGAT1 gene expression, total DGAT activity and seed oil content. In addition, reduced seed yield and germination rates were observed along with severe developmental abnormalities. These data suggest that in addition to its critical role in seed oil formation, DGAT1 enzyme may also be important for normal seed development in B. napus, although the underlying mechanism(s) remain to be determined.

Acyltransferase action in the modification of seed oil biosynthesis.

Seed oils represent a major source of dietary lipid and an increasingly valuable feedstock for industrial applications. There have been several attempts to modify seed oil content and composition through biotechnological approaches, resulting in the identification of several 'bottlenecks' limiting the accumulation of unusual fatty acids in storage lipids of oilseed crops. It has been suggested that the substrate preferences of endogenous acyltransferases play an important role in the utilization of unusual fatty acids in transgenic oilseeds, and there is increasing evidence that mechanisms of 'acyl-editing' via phospholipids are also involved in substrate trafficking and utilization. In this review, we will examine acyltransferase substrate specificity and selectivity in the context of designing strategies to maximize the accumulation of unusual fatty acids using biotechnological approaches.

Directed evolution of acyl-CoA:diacylglycerol acyltransferase: development and characterization of Brassica napus DGAT1 mutagenized libraries.

Metabolic flux to triacylglycerol (TAG) may be limited by the level of acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) activity. In some species, this enzyme also appears to play a role in the channeling of specific fatty acyl moieties into TAG. The objective of this work is to implement a directed evolution approach to enhance the catalytic efficiency of type-1 DGAT from Brassica napus (BnDGAT1). We generated randomly mutagenized libraries of BnDGAT1 in a yeast expression vector using error-prone PCR. The mutagenized libraries were used to transform a Saccharomyces cerevisiae strain devoid of neutral lipid biosynthesis and analyzed using a high-throughput screening (HTS) system. The HTS, recently developed for this purpose, consisted of a positive selection of clones expressing active DGAT mutants followed by quantification of DGAT activity by fluorescence detection of TAG in yeast cells. The initial results indicated that the positive selection system efficiently eliminated DGAT mutants lacking enzyme activity. Screening of 1528 selected mutants revealed that some DGAT clones had enhanced ability to synthesize TAG in yeast. This was confirmed by analysis of individual clones that could carry mutations resulting in an increased catalytic efficiency. The directed evolution approach could lead to the development of an improved plant DGAT1 for increasing seed oil content in oleaginous crops.

Is Rotavirus contributing to an increase of diarrhoea in a region of Spain?

Diarrhoeal illnesses are the most frequent of notifiable diseases in Aragon. Physicians notify diarrhoea cases with presumed infectious origin on a weekly basis. Following an increase in 2005-2006, we aimed to identify the responsible organism(s) in order to inform control measures. We described seasonality of diarrhoea notifications for 1998-2004 and 2005-2006. We calculated correlations between diarrhoea notifications and enteric pathogens diagnosed in two Aragonese laboratories, and applied linear regression using coefficients of determination (r2). In 2005-2006 the winter peak of diarrhoea notifications increased from 2494 to 3357 weekly cases (34.6%) and the peak in Rotavirus diagnoses from 15 to 39 weekly cases. The correlation of diarrhoea notifications with Rotavirus was 0.05 in 1998-2004 and 0.42 in 2005-2006. The model for 1998-2004 included Salmonella enterica, Giardia lamblia and Clostridium difficile (r2=0.08) and for 2005-2006 Rotavirus and Astrovirus (r2=0.24). Our results suggest that Rotavirus contributed to the increase of diarrhoea notifications. We recommend determining the disease burden of Rotavirus in order to guide vaccination policies.