MicroRNA-92a-CPEB3 axis protects neurons against inflammatory neurodegeneration

Neuroinflammation causes neuronal injury in multiple sclerosis (MS) and other neurological diseases. MicroRNAs (miRNAs) are important modulators of neuronal stress responses, but knowledge about their contribution to neuronal protection or damage during inflammation is limited. Here, we constructed a regulatory miRNA-mRNA network of inflamed motor neurons by leveraging cell type-specific miRNA and mRNA sequencing of mice undergoing experimental autoimmune encephalomyelitis (EAE). We found robust induction of miR-92a in inflamed spinal cord neurons and identified cytoplasmic polyadenylation element-binding protein 3 (Cpeb3) as a key target of miR-92a-mediated posttranscriptional silencing. We detected CPEB3 repression in inflamed neurons in murine EAE and human MS. Moreover, both miR-92a delivery and Cpeb3 deletion protected neuronal cultures against excitotoxicity. Supporting a detrimental effect of Cpeb3 in vivo, neuron-specific deletion in conditional Cpeb3 knockout animals led to reduced inflammation-induced clinical disability in EAE. Together, we identified a neuroprotective miR-92a-Cpeb3 axis in neuroinflammation that might serve as potential treatment target to limit inflammation-induced neuronal damage.

Calcium channel β3 subunit regulates ATP-dependent migration of dendritic cells

Migratory dendritic cells (migDCs) continuously patrol tissues and are activated by injury and inflammation. Extracellular adenosine triphosphate (ATP) is released by damaged cells or actively secreted during inflammation and increases migDC motility. However, the underlying molecular mechanisms by which ATP accelerates migDC migration is not understood. Here, we show that migDCs can be distinguished from other DC subsets and immune cells by their expression of the voltage-gated calcium channel subunit β3 (Cavβ3; CACNB3), which exclusively facilitates ATP-dependent migration in vitro and during tissue damage in vivo. By contrast, CACNB3 does not regulate lipopolysaccharide-dependent migration. Mechanistically, CACNB3 regulates ATP-dependent inositol 1,4,5-trisphophate receptor-controlled calcium release from the endoplasmic reticulum. This, in turn, is required for ATP-mediated suppression of adhesion molecules, their detachment, and initiation of migDC migration. Thus, Cacnb3-deficient migDCs have an impaired migration after ATP exposure. In summary, we identified CACNB3 as a master regulator of ATP-dependent migDC migration that controls tissue-specific immunological responses during injury and inflammation.

The journey of cardosin A in young Arabidopsis seedlings leads to evidence of a Golgi-independent pathway to the protein storage vacuole

The aspartic proteinase cardosin A is a vacuolar enzyme found to accumulate in protein storage and lytic vacuoles in the flowers and protein bodies in the seeds of the native plant cardoon. Cardosin A was first isolated several decades ago and has since been extensively characterized, both in terms of tissue distribution and enzyme biochemistry. In the native system, several roles have been attributed to cardosin A, such as reproduction, reserve mobilization, and membrane remodeling. To participate in such diverse events, cardosin A must accumulate and travel to different compartments within the cell: protein storage vacuoles, lytic vacuoles, and the cytoplasmic membrane (and eventually outside the cell). Several studies have approached the expression of cardosin A in Arabidopsis thaliana and Nicotiana tabacum with promising results for the use of these systems to study of cardosin A trafficking. A poly-sorting mechanism has been uncovered for this protein, as two different vacuolar sorting determinants, mediating different vacuolar routes, have been described. The first is a conventional C-terminal domain, which delivers the protein to the vacuole via the Golgi, and the second is a more unconventional signal-the plant-specific insert (PSI)-that mediates a Golgi-independent route. The hypothesis that these two signals are activated according to cell needs and in organs with high metabolic activity is investigated here. An Arabidopsis line expressing cardosin A under an inducible promoter was used to understand the dynamics of cardosin A regarding vacuolar accumulation during seed germination events. Using antibodies against different regions of the protein and combining them with immunofluorescence and immunocytochemistry assays in different young seedling tissues, cardosin A was detected along the secretory pathway to the protein storage vacuole, often associated with the endoplasmic reticulum. More interestingly, upon treatment with the drug Brefeldin A, cardosin A was still detected in protein storage vacuoles, indicating that the intact protein can bypass the Golgi in this system, contrary to what was observed in N. tabacum. This study is a good starting point for further research involving the use of fluorescent fusions and exploring in more detail the relationship between cardosin A trafficking and plant development.

The potential of almonds, hazelnuts, and walnuts SFE-CO2 extracts as sources of bread flavouring ingredients

Nuts have been part of the human diet since our early ancestors, and their use goes beyond nutritional purposes, for example, as aromatic sources for dairy products. This work explores the potential of almond (Prunus dulcis (Mill.) DA Webb), hazelnut (Corylus avellana L.), and walnut (Juglans regia L.) extracts as sources of food flavouring agents, suggesting a new added-value application for lower quality or excess production fruits. The extracts were obtained by supercritical fluid extraction with carbon dioxide and characterized by: quantification of the volatile fraction by HS-SPME GC-MS; sensory perception and description; and cytotoxicity against Vero cells. All extracts revealed potential as flavouring ingredients due to terpene abundance. No significant differences were observed for the minimal sensory perception, in which the odour threshold values ranged from 8.3 × 10^-4 to 6.9 × 10^-3 μg·mL^-1 for walnuts and almonds extracts, respectively. In contrast, the cytotoxic potential differed significantly among the extracts, and P. dulcis extract presented lower cytotoxicity. Notes as woody, fresh, and green were identified in the volatile intensifiers obtained from the P. dulcis extract. Thus, almond extract was identified as the most promising ingredient to increase the sensory value of food products, namely bread. This potential was verified by an increase in the odour perception of bread after adding 4 μL of extract to each 100 g of bread dough. The quantified eucalyptol and d-limonene terpenes - found in the P. dulcis extract - have improved the release of the pleasant and natural volatile compounds from bread crust and crumb compared to the control bread chemical and sensory profiles.

ESTUDO ONE-POT DA APLICAÇÃO DO CATALISADOR DE GRUBBS DE PRIMEIRA GERAÇÃO EM REAÇÕES DE METÁTESE DA PIPERINA E EUGENOL: A INFLUÊNCIA DA LIGAÇÃO DUPLA TERMINAL

ONE-POT STUDY OF THE APPLICATION OF CATALYST FIRST-GENERATION GRUBBS IN METATHESIS REACTIONS OF PIPERINE AND EUGENOL: THE INFLUENCE OF THE DOUBLE- BOND TERMINAL. In this paper, the piperine (PIP) and eugenol (EUG) organic compounds were used as substrates in olefin metathesis reactions catalyzed by first-generation Grubbs catalyst (G1) – [RuCl2(PCy3)2(=CHPh)], Cy is cyclohexyl and Ph is phenyl, in a one-pot system. The reactions occurred at 50 ºC, for 24, 48, or 96 h using the two substrates simultaneously in the ratio Ru:PIP:EUG of 1:1:1 and 1:10:10 mol. The results were evaluated by GC-MS, discussed in terms of the electronic and steric characteristics of the G1, and the structural proprieties of the substrates. In the Ru:PIP:EUG ratio of 1:1:1 mol, a dimeric species was observed for the olefin metathesis of EUG, in all time studied and in an additional experiment at 70 ºC for 48 h. When the Ru:PIP:EUG ratio was 1:10:10 mol, this dimer was not observed. Isomerization processes also were observed at all temperatures and catalyst:substrates ratio. The reaction yield increased with the raise of substrates amount. There was no cross-metathesis reaction. This fact was attributed to the chelating effect of the double coordination of the PIP to the catalyst.

Enhancing mitochondrial activity in neurons protects against neurodegeneration in a mouse model of multiple sclerosis

While transcripts of neuronal mitochondrial genes are strongly suppressed in central nervous system inflammation, it is unknown whether this results in mitochondrial dysfunction and whether an increase of mitochondrial function can rescue neurodegeneration. Here, we show that predominantly genes of the electron transport chain are suppressed in inflamed mouse neurons, resulting in impaired mitochondrial complex IV activity. This was associated with post-translational inactivation of the transcriptional co-regulator proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). In mice, neuronal overexpression of Ppargc1a, which encodes for PGC-1α, led to increased numbers of mitochondria, complex IV activity, and maximum respiratory capacity. Moreover, Ppargc1a-overexpressing neurons showed a higher mitochondrial membrane potential that related to an improved calcium buffering capacity. Accordingly, neuronal deletion of Ppargc1a aggravated neurodegeneration during experimental autoimmune encephalomyelitis, while neuronal overexpression of Ppargc1a ameliorated it. Our study provides systemic insights into mitochondrial dysfunction in neurons during inflammation and commends elevation of mitochondrial activity as a promising neuroprotective strategy.

Overexpression of ALDH1 and EMT marker profile are linked with unfavorable outcome in head and neck cancer

Background

The aim of this research was to assess the expression of aldehyde dehydrogenase 1 (ALDH1) and epithelial-mesenchymal transition (EMT) markers in head and neck squamous cell carcinoma (HNSCC), and to correlate them with the clinical and histopathological parameters of a patient cohort with follow-up over an 8-year period.

Material and Methods

For this, seventeen HNSCC and non-neoplastic adjacent epithelium (AE) samples were subjected to laser microdissection and real-time PCR to evaluate the mRNA expression of ALDH1, E-cadherin (E-CAD), N-cadherin (N-CAD), and vimentin (VIM). Also, immunohistochemistry was performed for ALDH1, E-CAD, N-CAD, and VIM in the tumor center (TC), invasion front (IF), and AE of the seventeen samples. Mann-Whitney, Kruskal-Wallis and Chi-square tests were used to correlate the mRNA and immunohistochemical expression with different variables, considering p<0.05. Kaplan-Meier curves were produced for local recurrence, regional metastasis and treatment.

Results

A mRNA overexpression of ALDH1 in primary tumors was associated with regional metastasis and a high ALDH1 immunostaining was related to metastasis and a worse patient outcome. Additionally, a favorable outcome was associated with the transition phase and an unfavorable outcome was associated with EMT event. An overall 26.9 months was observed with longer survival associated with surgery and radiotherapy.

Conclusions

However, due to the intense variability inherent to the indicator proteins in the EMT process, the complete profile markers related to this biological process should be continuous investigated.

Key words:Aldehyde dehydrogenase 1, epithelial mesenchymal transition, head and neck cancer, squamous cell carcinoma, follow-up study.

TRPV4-Mediated Regulation of the Blood Brain Barrier Is Abolished During Inflammation

Blood-brain barrier (BBB) dysfunction is critically involved in determining the extent of several central nervous systems (CNS) pathologies and here in particular neuroinflammatory conditions. Inhibiting BBB breakdown could reduce the level of vasogenic edema and the number of immune cells invading the CNS, thereby counteracting neuronal injury. Transient receptor potential (TRP) channels have an important role as environmental sensors and constitute attractive therapeutic targets that are involved in calcium homeostasis during pathologies of the CNS. Transient receptor potential vanilloid 4 (TRPV4) is a calcium permeable, non-selective cation channel highly expressed in endothelial cells. As it is involved in the regulation of the blood brain barrier permeability and consequently cerebral edema formation, we anticipated a regulatory role of TRPV4 in CNS inflammation and subsequent neuronal damage. Here, we detected an increase in transendothelial resistance in mouse brain microvascular endothelial cells (MbMECs) after treatment with a selective TRPV4 inhibitor. However, this effect was abolished after the addition of IFNγ and TNFα indicating that inflammatory conditions override TRPV4-mediated permeability. Accordingly, we did not observe a protection of Trpv4-deficient mice when compared to wildtype controls in a preclinical model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), and no differences in infarct sizes following transient middle cerebral artery occlusion (tMCAO), the experimental stroke model, which leads to an acute postischemic inflammatory response. Furthermore, Evans Blue injections did not show differences in alterations of the blood brain barrier (BBB) permeability between genotypes in both animal models. Together, TRPV4 does not regulate brain microvascular endothelial permeability under inflammation.

Living on the edge: the role of Atgolgin-84A at the plant ER-Golgi interface

The plant Golgi apparatus is responsible for the processing of proteins received from the endoplasmic reticulum (ER) and their distribution to multiple destinations within the cell. Golgi matrix components, such as golgins, have been identified and suggested to function as putative tethering factors to mediate the physical connections between Golgi bodies and the ER network. Golgins are proteins anchored to the Golgi membrane by the C-terminus either through transmembrane domains or interaction with small regulatory GTPases. The golgin N-terminus contains long coiled-coil domains, which consist of a number of α-helices wrapped around each other to form a structure similar to a rope being made from several strands, reaching into the cytoplasm. In animal cells, golgins are also implicated in specific recognition of cargo at the Golgi.Here, we investigate the plant golgin Atgolgin-84A for its subcellular localization and potential role as a tethering factor at the ER-Golgi interface. For this, fluorescent fusions of Atgolgin-84A and an Atgolgin-84A truncation lacking the coiled-coil domains (Atgolgin-84AΔ1-557) were transiently expressed in tobacco leaf epidermal cells and imaged using high-resolution confocal microscopy. We show that Atgolgin-84A localizes to a pre-cis-Golgi compartment that is also labelled by one of the COPII proteins as well as by the tether protein AtCASP. Upon overexpression of Atgolgin-84A or its deletion mutant, transport between the ER and Golgi bodies is impaired and cargo proteins are redirected to the vacuole. LAY DESCRIPTION: The Golgi apparatus is a specialised compartment found in mammalian and plant cells. It is the post office of the cell and packages proteins into small membrane boxes for transport to their destination in the cell. The plant Golgi apparatus consist of many separate Golgi bodies and is responsible for the processing of proteins received from the endoplasmic reticulum (ER) and their distribution to multiple destinations within the cell. Specialised proteins called golgins have been suggested to tether Golgi bodies and the ER. Here we investigate the plant golgin Atgolgin-84A for its exact within the Golgi body and its potential role as a tethering factor at the ER-Golgi interface. For this, we have fused Atgolgin-84A with a fluorescent protein from jellyfish and we are producing this combination in tobacco leaf cells. This allows us to see the protein using laser microscopy. We show that Atgolgin-84A localises to a compartment between the ER and Golgi that is also labelled by the tether protein AtCASP. When Atgolgin-84A is produced in high amounts in the cell, transport between the ER and Golgi bodies is inhibited and proteins are redirected to the vacuole.

Insights on the Extraction Performance of Alkanediols and Glycerol: Using Juglans regia L. Leaves as a Source of Bioactive Compounds

Glycerol and alkanediols are being studied as alternative solvents to extract phytochemicals from plant material, often as hydrogen bond donors in deep eutectic solvents (DESs). Many of those alcohols are liquid at room temperature, yet studies of their use as extraction solvents are scarce. In this work, glycerol and a series of alkanediols (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, and 1,2-hexanediol) were studied for the extraction of phenolic compounds from Juglans regia L. leaves, a rich source of this class of bioactive compounds. The extraction yield was quantified, and the bioactivity of both extracts and pure solvents was evaluated by measuring the anti-inflammatory and cytotoxic activities. The solvents showing the best combined results were 1,2 and 1,3-propanediol, as their extracts presented a high amount of phenolic compounds, close to the results of ethanol, and similar cytotoxicity against cervical carcinoma cells, with no impact on non-tumor porcine liver cells in the studied concentration range. On the other hand, none of the extracts (and solvents) presented anti-inflammatory activity. Overall, the results obtained in this work contribute to the study of alternative solvents that could potentially be used also as formulation media, highlighting the importance of walnut leaves as a source of bioactive compounds.

Hydroethanolic extract of Juglans regia L. green husks: A source of bioactive phytochemicals

Juglans regia L. (walnut) green husks are an important fraction of waste resulting from the walnut production, thus representing an interesting natural matrix to explore as a source of bioactive compounds. In this work, the hydroethanolic extract of walnut green husks was studied considering the phytochemical composition and the biological activity using different cell model assays, most of them evaluated for the first time for this matrix. From the HPLC-DAD-ESI/MSⁿ analysis, sixteen compounds were identified, being the extract mostly composed of naphthalene derivatives (including tetralone derivatives) and less abundant in phenolic compounds (hydroxycinnamic acids and flavonols). The cytotoxic potential of the extract was assessed against tumour (MCF-7, NCI-H460, HeLa and HepG2) and non-tumour (PLP2) cell lines. Moreover, the antioxidant activity of the extract was evaluated by inhibition of the oxidative haemolysis (OxHLIA) and the formation of thiobarbituric acid reactive substances (TBARS), and the anti-inflammatory potential by the inhibition of the NO production by the RAW264.7 cell culture. The antibacterial effects of the extract were also evaluated against Gram-negative and Gram-positive bacteria. The results obtained represent a stepping stone for the development of future applications using walnut green husks as a source of added value compounds with bioactive potential.

Mapping variation in breast cancer screening: Where to intervene?

Introduction

Mammography screening can reduce breast cancer mortality among women aged 50 years and older. Small geographic areas with lower breast cancer screening uptake may reflect gaps in screening efforts. Our objective was to identify the geographic variations of breast cancer screening uptake among women aged 50-74 years in the Lyon Metropole area, France.

Methods

We used spatial regression models within a generalized additive framework to determine the clusters of census blocks with significantly lower risk of breast cancer screening uptake. Census block-level data on breast cancer screening participation rates were calculated for women aged 50-74 years who did a mammography between 2015-2016 after being invited with a letter by the cancer screening organization. Using smoothed risk maps adjusting for covariates, we estimated the impact of the spatial distribution of deprivation index, part of opportunistic screening on breast cancer screening participation.

Results

Between 2015 and 2016, the participation rate of organized breast cancer screening was 49.9%. As hypothesized, women living in highly deprived census blocks had lower participation rates compared to less deprived. However, women living in rural areas with fewer certified mammography services than in urban areas had the highest participation rate. Spatial analyses identified four clusters, one located in an urban area and three in suburban areas.

Conclusions

Our analysis indicates that depending on the location of the cluster, the influence came from different variables. Knowing the impact of site-specific risk factors is important for implementing an appropriate prevention intervention.

Key messages

Spatial analysis for cancer screening can help to improve health initiatives. This study contributes to a better understanding of the cluster-specific factors that explain geographic disparities.

N-Linked Glycosylation Modulates Golgi-Independent Vacuolar Sorting Mediated by the Plant Specific Insert

In plant cells, the conventional route to the vacuole involves the endoplasmic reticulum, the Golgi and the prevacuolar compartment. However, over the years, unconventional sorting to the vacuole, bypassing the Golgi, has been described, which is the case of the Plant-Specific Insert (PSI) of the aspartic proteinase cardosin A. Interestingly, this Golgi-bypass ability is not a characteristic shared by all PSIs, since two related PSIs showed to have different sensitivity to ER-to-Golgi blockage. Given the high sequence similarity between the PSI domains, we sought to depict the differences in terms of post-translational modifications. In fact, one feature that draws our attention is that one is N-glycosylated and the other one is not. Using site-directed mutagenesis to obtain mutated versions of the two PSIs, with and without the glycosylation motif, we observed that altering the glycosylation pattern interferes with the trafficking of the protein as the non-glycosylated PSI-B, unlike its native glycosylated form, is able to bypass ER-to-Golgi blockage and accumulate in the vacuole. This is also true when the PSI domain is analyzed in the context of the full-length cardosin. Regardless of opening exciting research gaps, the results obtained so far need a more comprehensive study of the mechanisms behind this unconventional direct sorting to the vacuole.

Left Hepatic Lobectomy in the Living Donor-Comparison Between Open vs Laparoscopic Surgery

Laparoscopic hepatic surgery dramatically changed surgical practice in the last decades, improving outcomes in correctly selected patients. The reduction of postoperative pain, lower rate of complication, early return to work activities, and better esthetic result have been well described in several studies. The success of these procedures would inevitably clash in the more complex and delicate field of hepatectomy in the living donor. The 2nd International Consensus of the Conference on Laparoscopic Liver Surgery considers laparoscopic hepatectomy in the donor as an ideal procedure. The aim of this study is to compare the results between conventional and laparoscopic surgery; prospective data and retrospective analysis of 55 cases of live liver donor lobectomy were collected between January 2013 and June 2018. The mean age was 30.4 years in the video laparoscopic technique and 32.1 years in conventional surgery; the majority of donors were male in both groups. The mean time of ischemia was 70.2 minutes (range, 50-120 minutes) in laparoscopic surgery and 80.2 minutes (range, 50-165 minutes) in conventional surgery. The surgical time ranged from 270 to 800 minutes (mean, 452 minutes) in laparoscopic surgery and ranged from 300 to 600 minutes (mean, 424 minutes) in conventional surgery. The mean length of hospital stay was 2.2 days in laparoscopy and 3.97 days in conventional surgery. Laparoscopic left liver lobectomy in the living donor is safe and feasible. There was no significant difference in surgical time; however, the time of hospitalization was lower in patients submitted to laparoscopic technique.

Wild Morchella conica Pers. from different origins: a comparative study of nutritional and bioactive properties

BACKGROUND

Morchella conica Pers. is a species of fungus that belongs to the Morchellaceae family and was studied in order to obtain more information about this species, by comparing Portuguese and Serbian wild samples. Free sugars, fatty acids, tocopherols, organic and phenolic acids were analysed by chromatographic techniques. M. conica methanolic extracts were tested regarding antioxidant and antimicrobial properties. The absence of hepatotoxicity was confirmed in porcine liver primary cells.

RESULTS

The nutrition value varied between the two samples and the Serbian one gave the highest energy contribution and content in sugars, polyunsaturated fatty acids and phenolic compounds, while the Portuguese sample was richer in saturated and monounsaturated fatty acids, tocopherols and organic acids. In general, the Portuguese sample revealed the highest antioxidant potential (except for lipid peroxidation inhibition), while the Serbian one displayed higher antimicrobial activity. None of the samples revealed toxicity towards liver cells.

CONCLUSION

The present study provides new data concerning chemical characterization and bioactivity of Morchella conica Pers.

An integrated pipeline for sample preparation and characterization at the EMBL@PETRA3 synchrotron facilities

The characterization of macromolecular samples at synchrotrons has traditionally been restricted to direct exposure to X-rays, but beamline automation and diversification of the user community has led to the establishment of complementary characterization facilities off-line. The Sample Preparation and Characterization (SPC) facility at the EMBL@PETRA3 synchrotron provides synchrotron users access to a range of biophysical techniques for preliminary or parallel sample characterization, to optimize sample usage at the beamlines. Here we describe a sample pipeline from bench to beamline, to assist successful structural characterization using small angle X-ray scattering (SAXS) or macromolecular X-ray crystallography (MX). The SPC has developed a range of quality control protocols to assess incoming samples and to suggest optimization protocols. A high-throughput crystallization platform has been adapted to reach a broader user community, to include chemists and biologists that are not experts in structural biology. The SPC in combination with the beamline and computational facilities at EMBL Hamburg provide a full package of integrated facilities for structural biology and can serve as model for implementation of such resources for other infrastructures.

Expanding current knowledge on the chemical composition and antioxidant activity of the genus Lactarius

Despite the presence of toxic compounds in inedible mushrooms, the question whether the chemical nutrients and non-nutrients compositions in edible and inedible Lactarius species are similar remains unanswered. To answer this question, Lactarius citriolens Pouzar and Lactarius turpis (Weinm.) Fr., two inedible species, were studied in order to obtain information about their chemical composition and bioactivity. Free sugars, fatty acids, tocopherols, organic and phenolic acids were analysed by chromatographic techniques coupled to different detectors. L. citriolens and L. turpis methanolic extracts were tested regarding antioxidant potential (reducing power, radical scavenging activity and lipid peroxidation inhibition). The composition of macronutrients varied among the two species, but the profiles were similar between them and among other Lactarius species; L. citriolens gave the highest energy contribution, saturated fatty acids and organic acids, while the L. turpis sample was richer in free sugars, mono- and polyunsaturated fatty acids, tocopherols and phenolic compounds. L. turpis methanolic extract showed the highest antioxidant activity. The absence of hepatoxicity of the methanolic extracts was confirmed in porcine liver primary cells (in vitro conditions). The present study provided new information about wild L. citriolens and L. turpis, comparing their chemical composition and antioxidant properties with other Lactarius species, and expanding the knowledge about this genus.

Optimizing buffer conditions to improve crystallizability and SAXS measurement

The Sample Preparation and Characterization (SPC) facility at EMBL Hamburg is situated next to the PETRA3 beamlines for protein crystallography and small angle scattering (SAXS) that are operated by EMBL. The facility is equipped with molecular biology and biophysical instrumentation to carry out purification and characterization of macromolecular samples. It serves a mixed community of local EMBL scientists, beamline visitors and scientists from the European Union research area. Most incoming samples are destined for high-throughput crystallization at the facility or characterization by SAXS. The facility offers standardized quality control reports on each incoming sample, including characterization by mass spectrometry and Thermofluor. Based on this report, local staff can suggest and perform optimization protocols that increase the stability of the sample. For instance, Thermofluor screens(1) were developed that probe the effect of buffers and additives that are commonly used in sample preparation. These systematic screens provide a high-throughput method to identify stabilizing conditions for sample purification, storage and structural characterization. This technique has been also a valuable asset providing a high-throughput method for assessing the crystallizability of proteins by screening for conditions which contribute to the protein sample homogeneity, stability and solubility. The home-made screens have been tested on more than 200 different protein constructs at SPC facility. The aim of the SPC facility is to integrate off-line biophysical techniques with synchrotron beamlines, to offer the European user community a full package for sample characterization. The facility is especially geared towards cell biologists with little experience in structure determination. Expert staff is available to help to plan, perform and interpret biophysical experiments. It is possible for users to book SPC equipment together with their synchrotron beamtime, for protein purification, circular dichroism and isothermal calorimetry. Funded access to the facility is currently provided by the European Community's Seventh Framework Programme Biostruct-X. For further information, please contact spc@embl-hamburg.de.

Advances in nanomedicines for malaria treatment

Malaria is an infectious disease that mainly affects children and pregnant women from tropical countries. The mortality rate of people infected with malaria per year is enormous and became a public health concern. The main factor that has contributed to the success of malaria proliferation is the increased number of drug resistant parasites. To counteract this trend, research has been done in nanotechnology and nanomedicine, for the development of new biocompatible systems capable of incorporating drugs, lowering the resistance progress, contributing for diagnosis, control and treatment of malaria by target delivery. In this review, we discussed the main problems associated with the spread of malaria and the most recent developments in nanomedicine for anti-malarial drug delivery.

Regional differences regarding risk of developing rheumatoid arthritis in Stockholm County, Sweden: results from the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) study

OBJECTIVES

Rheumatoid arthritis (RA) is a complex disease that is associated with genetic and environmental factors. We have investigated geospatial variation in the risk of developing RA within Stockholm County, Sweden, with respect to established environmental risk factors for RA, as well as serologically defined subgroups of RA.

METHOD

Information regarding geographical location for 1432 cases and 2529 controls from the Epidemiological Investigation of Rheumatoid Arthritis (EIRA) study, living in Stockholm County at RA symptom onset, or matched date for controls, was used to estimate geospatial variation in risk. We used generalized additive models (GAMs) to create a risk surface, calculate odds ratios (ORs), and adjust for potential confounding by smoking, education level, and RA within family. We performed a stratified analysis based on the presence/absence of anti-citrullinated peptide antibodies (ACPA).

RESULTS

We found significant spatial variation in the odds of developing RA in Stockholm County. After adjustment for smoking, education level, and family history of RA, this geospatial variation remained. The stratified analysis showed areas with higher ORs for ACPA-positive RA and ACPA-negative RA, after adjusting for smoking, education level, and having a family history of RA. Living in the city of Stockholm was associated with decreased risk of RA.

CONCLUSIONS

The risk of developing RA in Stockholm County is not distributed evenly and there are areas of increased risk that could not be explained by known factors. Further investigations of local exposures or social factors are warranted.

Peritoneal and hepatic hydatid disease causing major bile duct destruction

Echinococcosis is endemic in Mediterranean regions and is found primarily in the liver. Biliary fistula is a common complication, but major biliary duct involvement is very rare, and occurs in 0.47% of patients with hepatic hydatid disease. Cyst rupture causing secondary peritoneal hydatidosis is a rare but serious complication. We report the case of a 27-year-old man with multiple peritoneal and hepatic hydatid cysts. The patient came to our attention with cholestatic jaundice. Imaging exams showed numerous peritoneal cysts and massive hydatid disease of the liver, which involved the hepatic confluence, with destruction of the right hepatic duct and fistula formation to the left hepatic duct. The patient was treated with pre-operative albendazole therapy and radical surgery, which consisted of resection of all peritoneal cysts and extended right hepatectomy with biliary reconstruction. No recurrence was seen on CT investigations on the 12th month following surgery. Radical surgical approach remains the treatment of choice.

Larval aquatic and terrestrial mites infesting parthenogenetic Ischnura hastata (Odonata: Coenagrionidae) from the Azores islands

We report here the prevalence of parasitism by water mites (Arrenurus sp.) and terrestrial mites (Leptus killingtoni) on parthenogenetic Ischnura hastata (Odonata: Coenagrionidae) from the Azores islands. Leptus killingtoni was only found on the island of Pico, and the prevalence of infestation was highly variable among the different ponds studied, ranging from 0 to 41%. Leptus killingtoni was observed on three of the four odonate species from the archipelago: I. hastata, I. pumilio, and Sympetrum fonscolombii, all of them new hosts for this species. Aquatic mites have been found parasitizing I. hastata females on the island of São Miguel. The prevalence of mite parasitism by Arrenurus sp. on I. hastata was very low, ranging from 12% (2003) to 1% (2008), and in most of the studied ponds, no mites were found attached to females. Although I. hastata coexists with a sexual congener species in the Azores (I. pumilio), they are syntopic in only a small fraction of ponds. Therefore, a comparison between I. hastata and I. pumilio was insufficient to test the predictions of the Red Queen Hypothesis, and further research on parasitism rates in both species needs to be done. In any case, the low prevalence of mite parasitism found in the Azores, coupled with the fact that most of the populations in the archipelago are almost free from competitors and predators, could explain the persistence of these I. hastata parthenogenetic populations, despite their low levels of genetic variation.

The Ca2+-dependent protease Calpain A regulates Cactus/I kappaB levels during Drosophila development in response to maternal Dpp signals

Regulation of NF kappaB activity is central to many processes during development and disease. Activation of NF kappaB family members depends on degradation of inhibitory I kappaB proteins. In Drosophila, a nuclear gradient of the NF kappaB/c-rel protein Dorsal subdivides the embryonic dorsal-ventral axis, defining the extent and location of mesodermal and ectodermal territories. Activation of the Toll pathway directs Dorsal nuclear translocation by inducing proteosomal degradation of the I kappaB homologue Cactus. Another mechanism that impacts on Dorsal activation involves the Toll-independent pathway, which regulates constitutive Cactus degradation. We have shown that the BMP protein Decapentaplegic (Dpp) inhibits Cactus degradation independent of Toll. Here we report on a novel element of this pathway: the calcium-dependent protease Calpain A. Calpain A knockdowns increase Cactus levels, shifting the Dorsal gradient and dorsal-ventral patterning. As shown for mammalian I kappaB, this effect requires PEST sequences in the Cactus C-terminus, implying a conserved role for calpains. Alteration of Calpain A or dpp results in similar effects on Dorsal target genes. Epistatic analysis confirms Calpain A activity is regulated by Dpp, indicating that Dpp signals increase Cactus levels through Calpain A inhibition, thereby interfering with Dorsal activation. This mechanism may allow coordination of Toll, BMP and Ca(2+) signals, conferring precision to Dorsal-target expression domains.

Analysis of partner of inscuteable (mPins) expression in the developing mouse eye

PURPOSE

Asymmetric cell division (ACD) is the fundamental mechanism underlying the generation of cellular diversity in invertebrates and vertebrates. During Drosophila neuroblast division, this process involves stabilization of the apical complex and interaction between the Inscuteable (Insc) and Partner of inscuteable (Pins) proteins. Both cell-intrinsic factors and cell-cell interactions seem to contribute to cell fate decisions in the retina. The Pins protein is known to play a major role in the asymmetric segregation of cell fate determinants during development of the central nervous system in general, but its role in asymmetric cell divisions and retinoblast cell fate has never been explored. The primary aim of this study was to determine the spatial distribution and time course of mouse homolog of Drosophila Partner of Inscuteable (mPins) expression in the developing and adult mouse eye.

METHODS

The expression pattern of mPins was studied in the mouse eye from embryonic (E) stage E11.5 until adulthood, by semiquantitative RT-PCR, in situ hybridization, and immunohistochemistry. In addition, variations in mRNA and protein levels for mPins were analyzed in the developing postnatal and adult lens, by semiquantitative RT-PCR, western blot analysis, in situ hybridization, and immunohistochemistry.

RESULTS

We detected mPins mRNA at early stages of mouse embryonic eye development, particularly in the neuroblastic layer. In early postnatal development, mPins mRNA was still detected in the neuroblastic layer, but also began to be detectable in the ganglion cell layer. Thereafter, mPins mRNA was found throughout the retina. This pattern was maintained in differentiated adult retina. Immunohistochemical studies showed that mPins protein was present in the neuroblastic layer and the ganglion cell layer during the early stages of postnatal retinal development. At these stages, mPins protein was colocalized with Numb protein, a marker of the ACD. At later postnatal stages, mPins protein was present in all retinal nuclear layers and in the inner plexiform layer. It continued to be detected in these layers in the differentiated retina; the outer plexiform layer and the photoreceptor inner segments also began to display positive immunostaining for mPins. In the adult retina, mPins was also detected in the retinal pigment epithelium and choroidal melanocytes. Throughout development, mPins protein was detected in nonretinal tissues, including the cornea, ciliary body, and lens. We focused our attention on lens development and showed that mPins protein was first detected at E14.5. The most striking results obtained concerned the lens, in which mPins protein distribution switched from the anterior to the posterior region of the lens during embryonic development. Interestingly, in the postnatal and adult lens, mPins protein was detected in all lens cells and fibers.

CONCLUSIONS

We provide the first demonstration that mPins protein is expressed from embryonic stages until adulthood in the mouse eye. These results suggest that mPins plays important roles in eye development. This work provides preliminary evidence strongly supporting a role for mPins in the asymmetric division of retinoblasts, and in the structure and functions of adult mouse retina. However, the link between the presence of mPins in different ocular compartments and the possible occurrence of asymmetric cell divisions in these compartments remains to be clarified. Further studies are required to elucidate the in vitro and in vivo functions of mPins in the developing and adult human eye.

Differential regulation of Dlg1, Scrib, and Lgl1 expression in a transgenic mouse model of ocular cancer

PURPOSE

Discs large (dlg), scribble (scrib), and lethal giant larvae (lgl) are major suppressor genes in Drosophila melanogaster. They encode proteins that regulate cell polarity and cell proliferation in Drosophila and mammals. However, their basic oncogenic roles have not yet been established in mouse epithelial ocular cancer. We evaluated the potential implication of these proteins in tumorigenesis of adenocarcinomas originating from the retinal pigmented epithelium of the Trp1/Tag transgenic mouse model. We examined the changes in the distribution and levels of these proteins in mouse ocular tissues from the Trp1/Tag mouse model.

METHODS

The expression patterns of theses genes and their corresponding proteins in normal mouse ocular tissues were studied by in situ hibridization and immunohistofluorescence experiments. In addition, variations in mRNA and proteins levels and protein distributions for Dlg1, Scrib, and Lgl1 were analyzed in the ocular tissues from Trp1/Tag transgenic mouse model by reverse transcription polymerase chain reaction (RT-PCR), western blot analysis, and immunohistofluorescence.

RESULTS

We found that mouse Dlg1, Scrib, and Lgl1 are widely distributed in normal ocular tissues, particularly in retinal neurons. We found that the three proteins are mislocalized in retinal layers during ocular carcinogenesis. These mislocalizations were correlated to the early dysplastic stages of ocular tumorigenesis. Additionally, the mislocalization of each protein was associated with its downregulation. Decreased levels of these proteins may be considered as late-stage markers of the disease but also as markers of the invasive stage of this cancerous process. This downregulation may be involved in epithelial-mesenchymal transition in this mouse ocular tumoral model. This would be consistent with the downregulation of E-cadherin and upregulation of N-cadherin expression observed in this model.

CONCLUSIONS

This is the first study to demonstrate the involvement of Dlg1, Scrib, and Lgl1 in a mouse with ocular adenocarcinoma and the simultaneous involvement of these proteins in the same cancer. Our results indicate that both the mislocalization and downregulation of these proteins may be involved together in ocular carcinogenesis.

The RNA-binding protein Musashi-1 is produced in the developing and adult mouse eye

PURPOSE

Musashi-1 (Msi1) is an RNA-binding protein produced in various types of stem cells including neural stem/progenitor cells and astroglial progenitor cells in the vertebrate central nervous system. Other RNA-binding proteins such as Pumilio-1, Pumilio-2, Staufen-1, and Staufen-2 have been characterized as potential markers of several types of stem or progenitor cells. We investigated the involvement of Msi1 in mouse eye development and adult mouse eye functions by analyzing the profile of Msi1 production in all ocular structures during development and adulthood.

METHODS

We studied Msi1 production by in situ hybridization and immunohistochemistry of ocular tissue sections and by semi-quantitative RT-PCR and western blot analysis from the embryonic stage of 12.5 days post coitum (E12.5 dpc) when the first retinal ganglion cells (RGCs) begin to appear to the adult stage when all retinal cell types are present.

RESULTS

Msi1 mRNA was present at all studied stages of eye development. Msi1 protein was detected in the primitive neuroblastic layer (NbL), the ganglion cell layer (GCL), and in all major differentiated neurons of postnatal developing and adult retinae. During postnatal developing stages, faint diffuse Msi1 protein staining is converted to a more specific distribution once mouse retina is fully differentiated. The most striking result of our study concerns the large amounts of Msi1 protein and mRNA in several unexpected sites of adult mouse eyes including the corneal epithelium and endothelium, stromal keratocytes, progenitor cells of the limbus, equatorial lens stem cells, differentiated lens epithelial cells, and differentiating lens fibers. Msi1 was also found in the pigmented and nonpigmented cells of the ciliary processes, the melanocytes of the ciliary body, the retinal pigment epithelium, differentiated retinal neurons, and most probably in the retinal glial cells such as Müller glial cells, astrocytes, and the oligodendocytes surrounding the axons of the optic nerve. Msi1 expression was detected in the outer plexiform layer, the inner plexiform layer, and the nerve fiber layer of fully differentiated adult retina.

CONCLUSIONS

We provide here the first demonstration that the RNA-binding protein, Msi1, is produced in mouse eyes from embryonic stages until adulthood. The relationship between the presence of Msi1 in developing ocular compartments and the possible stem/progenitor cell characteristics of these compartments remains unclear. Finally, the expression of Msi1 in several different cell types in the adult eye is extremely intriguing and should lead to further attempts to unravel the role of Msi1 in cellular and subcellular RNA metabolism and in the control of translational processes in adult eye cells particularly in adult neuronal dendrites, axons, and synapses.

Outpatient dermatology major surgery: a 1-year experience in a Spanish tertiary hospital

INTRODUCTION

The constant increase in the incidence of skin cancer together with the requirement for maximum exploitation of available medical resources has meant that dermatological major surgery on an outpatient basis has greatly increased in recent years.

OBJECTIVE

This article reviews the practice of dermatological surgery in an outpatient setting over a 1-year period. Its purpose is to analyse the number of surgical procedures, the type of cutaneous processes treated and the kind of surgical intervention and anaesthesia used. We also assessed the percentage of cancellations, postsurgical hospital admission and postsurgical complications. Clinicopathological correlation and complete tumour removal were also evaluated.

MATERIAL AND METHODS

Our clinical experience of major surgery of outpatients at the dermatology department of the Hospital Juan Canalejo in A Coruña (Spain), analysing 565 patients in a non-randomized pilot study running from January to December 2003, is presented.

RESULTS

Six hundred and forty-four surgical procedures were performed on a total of 565 patients. The three main cutaneous processes treated were basal cell carcinoma (240), squamous cell carcinoma (117) and melanoma (77). The most frequent type of procedure was direct closure (346), followed by exeresis and flap (133) and partial- or full-thickness skin graft (29), nail apparatus surgery (56) and lip surgery (33). Twelve patients were admitted to hospital after surgery owing to the complexity of their operations or to complications arising during surgery. Five hundred and fifty-three patients were discharged after being kept under observation for a few hours. Seventeen patients (3%) suffered complications following surgery, which consisted of partial implant failure (six cases), infection of the surgical wound (six cases), intense pain (four cases) and haemorrhage (one case). There was a good clinicopathological correlation in 90.78% of non-melanoma skin cancers, of which 92.03% were completely removed.

CONCLUSIONS

Medium and high complexity operations for dermatological processes, traditionally performed on hospitalized patients, can be conducted on an outpatient basis. This allows hospitalization costs and waiting lists to be reduced and affords the possibility of achieving better morbidity rates and medical care than in the standard hospital setting.

Lupus erythematosus tumidus: a series of 26 cases

OBJECTIVE

To study 26 cases of lupus erythematosus tumidus (LET), a subset of chronic cutaneous lupus erythematosus (CCLE), referred to in the literature as a rare entity.

PATIENTS AND METHODS

A retrospective study was conducted of 26 patients diagnosed with LET between 1996 and 2002. The clinical characteristics, histopathologic and laboratory findings, response to treatment, association with other subsets of lupus, course, and diagnostic criteria were analyzed.

RESULTS

The incidence by sex was similar. The mean age of presentation was 49.19 years. The clinical presentation usually involved erythematous, edematous plaques located on the face, chest, back, or extremities, related to sun exposure. A dermal lymphocytic infiltrate with a perivascular disposition and differing degrees of mucin deposition was observed in all cases. Minimal epidermal changes were present in 18 cases, and 11 of these also showed minimal dermal-epidermal changes. Only one case showed dermal-epidermal changes without any epidermal alteration. Direct immunofluorescence test was performed in 15 patients, and 11 were negative. All cases showed a benign course without systemic manifestations. The response to topical steroids or antimalarial treatment was excellent, but a seasonal recurrence was usually observed. Discussion No defined criteria for LET are universally accepted. The main controversies are the acceptance of LET as a separate subset of CCLE, and the histopathologic diagnostic features, mainly the presence or absence of epidermal and dermal-epidermal changes in these lesions.

CONCLUSIONS

No inflexible histologic criteria should be employed for the diagnosis of LET. This subset of lupus erythematosus is characterized by intense photosensitivity, definite clinical lesions, a benign course, the absence of systemic disease, good response to antimalarial treatment, and a tendency to recur. More studies should be performed in order to establish the true incidence of LET because this subset of CCLE is probably underestimated.

Erythroplasia of Queyrat with urethral involvement: treatment with carbon dioxide laser vaporization

BACKGROUND

Erythroplasia of Queyrat is an uncommon carcinoma in situ that usually arises on the mucosa of the glans penis or prepuce as red, shiny, sharply demarcated velvety plaques. The treatment is often difficult and associated with significant recurrence rates, especially in cases with urethral involvement.

OBJECTIVE

To evaluate carbon dioxide laser treatment in a case of erythroplasia of Queyrat with urethral involvement.

MATERIALS AND METHODS

We report a patient with erythroplasia of Queyrat involving the urethra who was treated with carbon dioxide laser vaporization.

RESULTS

Treatment with carbon dioxide laser vaporization resulted in an excellent cosmetic and functional status outcome for the glans penis and urethral lesions.

CONCLUSION

Carbon dioxide laser vaporization is probably the initial elective treatment for erythroplasia of Queyrat with urethral involvement in young immunocompetent patients. A follow-up is necessary, and new sessions of treatment should be quickly performed if recurrence occurs.

Association between IGF-IR gene polymorphisms and productive and reproductive traits in Holstein cows

The association between single-strand conformation polymorphism (SSCP) in the gene of insulin-like growth factor-I receptor (IGF-IR) and age at first calving (AFC), calving interval (CI), lactation length (LL), and milk yield (MY) was studied using 106 graded Holstein females. The polimerase chain reaction (PCR) with specific initiating oligonucleotides, resulted an amplified fragment of 335pb. The population genotypes frequencies were 82.1% and 17.9%, for AA and AB genotypes, respectively. The frequency of A allele was 0.91 and 0.09 of B allele. No association between the identified polymorphism and AFC, CI, and MY was observed. The LL was positively associated (P<0.05) with the absence of B allele. Animals carrying the AA genotype presented a longer lactation period.

Necrobiotic xanthogranuloma associated with lymphoplasmacytic lymphoma. Palliative treatment with carbon dioxide laser

Necrobiotic xanthogranuloma (NXG) with paraproteinemia is a rare non-x histiocytosis with conspicuous lesions mainly located on the periorbital skin. A 68-year-old woman, with a previous history of lymphoplasmacytic lymphoma associated with IgG monoclonal gammopathy over a period of almost 4 years, presented typical lesions of NXG on the periorbital regions and left buttock. Treatment with dioxide carbon laser resulted in great improvement of cutaneous lesions, and no evidence of relapse after a 12-month follow-up. The association of NXG with lymphoplasmacytic lymphoma has not been previously described to our knowledge. The treatment of these lesions represents a true challenge for the clinician and palliative treatment of cutaneous lesions of NXG with CO(2) laser may constitute an alternative treatment in selected cases.

Differentiation and gene flow among island and mainland populations of the true armyworm,Pseudaletia unipuncta(Haworth) (Lepidoptera: Noctuidae)

The genetic structure of populations of the true armyworm, Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae), in the Azores archipelago was studied using polyacrylamide-gel electrophoresis. Four enzyme systems (aldehyde oxidase, esterase, phosphoglucomutase, and phosphoglucose isomerase) were examined in six populations from islands in the Azores (Santa Maria, São Miguel, Terceira, Pico, Faial, Flores) and compared with those from populations from mainland Portugal and Canada. The North American and European populations are not clearly separated from the Azorean ones. Similarly, studies of different enzyme systems (aldehyde oxidase, esterase, malic enzyme, sorbitol dehydrogenase, manose-6-phosphate isomerase, and phosphoglucomutase) over 2 years (1997 and 1998) at different times of the year (spring, summer, and autumn) and at three different altitudes (0, 250, and 500 m above sea level) on three different islands (Santa Maria, São Miguel, and Faial) uncovered no distinct differences. These results, obtained from classically used loci, suggest that there is still some gene flow between sites or that island populations have not been isolated for sufficient time to have diverged from founder populations.

Chromomycosis due to Exophiala jeanselmei in a renal transplant recipient

Chromomycosis is a rare mycotic infection that is more frequent in tropical and subtropical regions. Dematiaceous fungi are the causal agents of this mycosis. Several cases of chromomycosis in organ transplant recipients have been reported. We present a case of chromomycosis by Exophiala jeanselmei in a Spanish male who had received a renal transplant several months previously, and was receiving treatment with tacrolimus, prednisone and mycophenolate mofetil. Very few cases of chromomycosis due to Exophiala have been reported, and this is, to our knowledge, the first European case.

New benzodiazepines alter acetylcholinesterase and ATPDase activities

This study examines the effect of new 1,5 benzodiazepines on acetylcholinesterase (AChE) and ATPDase (apyrase) activities from cerebral cortex of adult rats. Simultaneously, the effects of the classical 1,4-benzodiazepine on these enzymes were also studied for comparative purpose. The compounds 2-trichloromethyl-4-phenyl-3H-1,5-benzodiazepin and 2-trichloromethyl-4(p-methyl-phenyl)-3H- 1,5-benzodiazepin significantly inhibited acetylcholinesterase activity (p < 0.01) when tested in the range of 0.18-0.35 mM. The inhibition caused by these two new benzodiazepines was noncompetitive in nature. Similarly, at concentrations ranging from 0.063 to 0.25 mM, the 1,5 benzodiazepines inhibited ATP and ADP hydrolysis by synaptosomes from cerebral cortex (p < 0.01). However, the inhibition of nucleotide hydrolysis was uncompetitive in nature. Our results suggest that, although diazepam and the new benzodiazepines have chemical differences, they both presented an inhibitory effect on acetylcholinesterase and ATPDase activities.

Temperature and developmental plasticity of muscle phenotype in herring larvae

Myogenesis, the expression of myofibrillar protein isoforms and the development of muscle innervation were investigated in Clyde herring (Clupea harengus L.) in two successive spawning seasons at temperatures ranging from 5 &deg;C to 15 &deg;C. Myotube formation occurred in a rostral to caudal progression at similar somite stages at all temperatures. Superficial mononuclear muscle pioneer fibres were present at the horizontal septum. Myofibrillogenesis was retarded with respect to somite stage at low temperatures; for example, by the 50-somite stage, myofibrils were observed in the muscle pioneers of the first 31 somites at 12 &deg;C, but only the first 20 somites at 5 &deg;C. In the electron microscope, the earliest stages of myofibril assembly were observed in the muscle pioneer cells and in a proportion of the multinucleated myotubes within the same somite. By the end of somitogenesis, the density of myofibrils in the rostral myotomes was much higher at 15 &deg;C than at 5 &deg;C. Embryonic isoforms of myosin light chain 2 (LC2), troponin I and troponin T were identified in the presumptive white muscle using two-dimensional gel electrophoresis. Expression of the embryonic isoforms was gradually switched off during the larval stages. The size range over which embryonic isoforms were present was inversely related to rearing temperature. For example, the adult pattern of myosin LC2 expression was established at 11 mm total length (TL) at 15 &deg;C, but not until 15 mm TL at 5 &deg;C. Acetylcholinesterase staining was apparent at the myosepta in 31-somite stage embryos at 15 &deg;C, but not until approximately the 40-somite stage at 5 &deg;C. The red muscle fibres of larvae were initially innervated only at their myoseptal ends. The temperature at which the red muscle fibres became multiply innervated was inversely related to body size, occurring at 12&shy;14 mm at 12 &deg;C, but not until 16&shy;19 mm at 5 &deg;C. We conclude that the temperature during early development determines the relative timing and degree of expression of the myogenic programme, resulting in significant phenotypic variation in the swimming muscles of the larval stages. Our results highlight a potential mechanism whereby early thermal experience could influence survival and hence the strength of particular year classes of fish.

Temperature and myogenesis in embryos of the Atlantic herring Clupea harengus

The development of axial muscles has been investigated in spring-spawning Atlantic herring (Clupea harengus L.) reared at 5, 8, 12 and 15 &deg;C. In 1994, around 90 % of embryos hatched after 28 days at 5 &deg;C, 16 days at 8 &deg;C, 9 days at 12 &deg;C and 8 days at 15 &deg;C. The somites were formed from cells of the paraxial mesoderm in a rostral to caudal direction, starting at the neural plate stage. Somites were added at rates ranging from one every 3 h at 5 &deg;C to one every 52 min at 15 &deg;C. A small number of myoblasts, located adjacent and lateral to the notochord, elongated to span the somite to form mononuclear myotubes. The majority of muscle fibres were formed by the fusion of 2&shy;5 myoblasts to produce multinucleated myotubes that subsequently differentiated into either superficial or inner fibre types. The timing of myogenesis with respect to somite stage and the initial appearance of the gut, pectoral fin buds and pronephric tubules was found to vary with development temperature. For rostral myotomes, the synthesis of contractile filaments and myofibril assembly were first observed at the 42-, 38- and 27-somite stages at 5, 8 and 12 &deg;C, respectively. The differentiation of myotubes into morphologically recognisable muscle fibre types first occurred at the 62-somite stage at 5 &deg;C, at the 48-somite stage at 8 &deg;C and as early as the 40-somite stage at 12 &deg;C. Cell proliferation experiments with 5-bromo-2'-deoxyuridine showed that another population of myoblasts was activated on the surface of muscle fibres just prior to hatching. Development temperature also affected muscle cellularity; there were 43 % more inner muscle fibres in the myotomes of 1-day-old larvae reared at 12 &deg;C than at 5 &deg;C (P&lt;0.02).