The ER-Golgi-Intermediate compartment : dynamics and cargo sorting studied by time-lapse video microscopy

Membrane trafficking in mammalian cells proceeds through several steps including sorting the correct components to be transported, packaging them into appropriate containers and conveying the carriers to the proper organelles with which they fuse. All these steps are tightly regulated by several machineries like coats, fusion proteins, motors, tethers, Rabs and other regulatory components. The investigation of the molecular mechanisms of these machineries unraveled the trafficking events taking place between different compartments; but these findings did not elucidate how organelles can persist and maintain their integrity in a constantly dynamic environment. Two major controversial models are constantly debated: the stability and the maturation of compartments. The stability model favors the notion that compartments are long-lived stations in which cargo material is sorted from the resident components and transits from one organelle to the other in vesicular carriers. The maturation hypothesis suggests that organelles of the secretory pathway are transient stations that form at the level of the ER; once they leave it, they continuously homo-fuse and recycle back machinery components to the previous station. A particular discordance resides in defining the ER-Golgi-intermediate compartment (ERGIC) features: is it a stable or a maturing organelle? The ERGIC defined by the cycling lectin ERGIC-53 consists of tubulovesicular clusters. Here, I show by live imaging that GFP-ERGIC-53 mainly localizes to long-lived stationary and some short-lived highly mobile elements. Unlike the anterograde marker VSV-G-GFP, GFP-ERGIC-53 does not vectorially move to the Golgi upon exit from the ERGIC, as assessed by a novel quantitative vector field method. Dual color imaging of GFP-ERGIC-53 and a secretory protein (signal-sequence-tagged DsRed) reveals that the stationary elements are sites of repeated sorting of retrograde and anterograde cargo, and are interconnected by highly mobile elements. Based on these results, I conclude that the ERGIC is a membrane compartment in the true sense and not simply a collection of mobile carriers mediating protein traffic from endoplasmic reticulum to Golgi. The finding that the ERGIC is a true compartment opens new perspectives for the dissection of ERGIC functions and the molecular machineries that are recruited

Kaposi sarcoma in an HIV-negative Tunisian patient: A rare cause of metatarsalgia

AbstractBackgroundKaposi sarcoma (KS) is an angioproliferative neoplasm that is commonly associated with human herpes virus-8 (HHV-8) and human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). KS with osseous involvement is a rare occurrence, and is far more common in acquired immunodeficiency syndrome (AIDS)-related KS.Case presentationWe present a 32-year-old Tunisian man, HIV negative, who presented with a 4-year history of atraumatic mechanical metatarsalgia that progressively worsened with a limping gait. Physical examination revealed marked symmetrical forefoot lymphedema and a painful restricted left knee joint movement. Physical examination showed purple-blue plaques and nodules on the feet and ankles. Serologic tests for HIV and syphilis were negative. Plain radiography of the feet revealed numerous small lytic lesions. There were also scattered lytic lesions in the metaphysis of the proximal tibia and fibula. Osteolysis was predominantly left. Magnetic resonance imaging of the feet showed abnormal bone marrow signal of metatarsals and phalanges. Skin lesion biopsy yielded the diagnosis of Kaposi sarcoma. The disease was managed with chemotherapy including vinblastine.ConclusionIn a patient presenting with metatarsalgia without a commonly detected cause, it is mandatory to search for other lesions that may point to a rare diagnosis as KS which is famous for involvement of the metatarsal bone

Impact of season and foliar fertilisers on phenolics of leaves of Chemlali olive cultivar

The olive leaves are known as a source of nutraceuticals due to their richness in phenolics. Numerous studies explored the effect of several factors on leaf phenolics but few studies focused on the impact of foliar fertilizers on leaf phenolics. In this context, our study aimed to explore the effect of season and foliar fertilisers on phenolics in leaves of “Chemlali” olive cultivar. Four foliar fertilisers were sprayed separately at different seasons. Total polyphenol, total flavonoid ortho-diphenol and oleuropein contents were assessed in fresh olive leaves. Our results showed that polyphenols and ortho-diphenols reached their maximum in April, decreased in August and rose again in November. Flavonoid showed an inverted trend and were the most affected by the different foliar fertilisers. Oleuropein content had two peaks in April and November and was not affected by foliar fertilisers. Taking into consideration these results, the optimal periods to collect olive leaves are April and November. Our study brought out evidences about the impact of foliar nutrition on olive leaves

Changes in volatiles of olive tree Olea europaea according to season and foliar fertilization

In the present study, four foliar fertilizers (FF1, FF2, FF3 and FF4) were separately sprayed on Chemlali olive trees at different moments of the vegetative cycle. FF1 (rich in nitrogen) was applied during the vegetation stage (Last January-February) at a dose of 5 L/ha per spray (three sprays per season). FF2 (rich in boron, magnesium and sulphur), FF3 (rich in phosphorus and potassium) and FF4 (rich in phosphorus and calcium) were applied respectively during the stages of flowering (Last March-April), fruit growth (July-August) and ripening (October-November), at a dose of 3 L/ha per spray (three sprays per season for each fertilizer).The volatile fraction was analysed by GC-MS, 46 volatile compounds were identified and their amount were expressed as relative abundance (%). In a general view, the most abundant volatiles in Chemlali olive leaves across the vegetative cycle were (E)-2-hexenal, nonanal, (E)-β-damascenone, 3-ethenyl pyridine and β-caryophyllene. The levels of these main compounds and the general composition of the volatile fraction varied significantly through season.The volatile levels were mainly affected by the two foliar fertilizers enriched with nitrogen and Boron respectively. The most affected volatiles were (E)-2-hexenal, nonanal, 3-ethenyl pyridine, (E,E)-α-farnesene, and (E)-nerolidol. Less impact was noticed after the use of the other foliar fertilizers.Our study is the first investigation bringing data about the variation of leaf volatile profile of Chemlali cultivar across a vegetative cycle and showing the impact of nutrient foliar sprays on olive leaf volatile

Spondylodiscite tuberculeuse : 12 ans d'expérience dans un centre hospitalier en Tunisie

Objectifs : Décrire les particularités épidémiologiques, cliniques et paracliniques des spondylodiscites tuberculeuses et déterminer les facteurs prédictifs d’une évolution défavorable. Patients et Méthode: Etude rétrospective sur une période de 12 ans. Le diagnostic a été porté sur des preuves bactériologiques, anatomopathologiques ou sur un faisceau d’arguments. Résultats : Il s’agissait de 49 patients (26F/23H), âgés en moyenne de 51,84 ans. Le délai moyen de diagnostic était de 6,65 mois. Un facteur prédisposant à l’infection a été relevé chez 38,7% des patients. L’étage lombaire était le plus touché (67,3%). L’imagerie par résonnance magnétique était pathologique dans tous les cas où elle a été effectuée. Le diagnostic de certitude a été porté dans 9 cas sur une preuve histologique. La ponction biopsie disco-vertébrale a permis de confirmer le diagnostic dans 6/36 cas. Tous les patients ont reçu un traitement anti-tuberculeux d’une durée moyenne de 13,59 mois associé à un geste interventionnel dans 8 cas. L’évolution était favorable dans 84,2% des cas. Nous avons identifiés quatre facteurs prédictifs d’une évolution défavorable: une hyperleucocytose initiale ≥11500 éléments/mm3 (p=0,031), la présence d’abcès ou de collection à l’imagerie (p=0,018); un tassement vertébral à l’IRM (p=0,018) et l’existence de déformation osseuse avant correction chirurgicale (p<0,001). Conclusion: La spondylodiscite tuberculeuse devrait être suspectée devant toute rachialgie inflammatoire. Une prise en charge précoce est la clé pour éviter les complications neurologiques et ostéo-articulaires

Femoroacetabular Impingement: Anatomy and Pathogenesis

Femoroacetabular impingement (FAI) is an often unrecognized hip disorder in young adults that can lead to early hip osteoarthritis and a decrease in sports performance. The diagnosis and treatment of this entity have rapidly evolved in recent years. Hip arthroscopy finds its place in the treatment of this conflict, and its indications are more and more frequent. The technical challenge of this operation involves a relatively long learning curve and a good knowledge of the hip anatomy in order to minimize the risk of complications and iatrogenic lesions. In addition to intra-articular structures of the hip joint, the anatomical structures that may be affected by the main and accessory arthroscopic approach are primarily the lateral femorocutaneous nerve, the lateral circumflex femoral artery, the medial circumflex femoral artery, and the circumflex superior iliac artery. A little further, 3–5 cm from the main portals, we must pay attention to the femoral nerve, the sciatic nerve, the superior gluteal nerve, the profunda femoris artery, the superficial femoral artery, and the common femoral artery. The pathogenesis of femoroacetabular impingement is not fully understood. The multifactorial origin is still relevant today. We have divided factors incriminated in the genesis of FAI into three groups

An Access Control Model for Web Databases

International audienceThe majority of today's web-based applications are based on back-end databases to process and store business information. Containing valuable business information, these systems are highly interesting to attackers and special care needs to be taken to prevent them from malicious accesses. In this paper, we propose (RBAC + ), an extension of the NIST RBAC (Role-Based Access Control) standard with the notions of application, application profile and sub-application session to distinguish end users that execute the same application, providing them by only the needed roles and continuously monitoring them throughout a whole session. It is based on business application logic rather than primitive reads and writes to enhance the ability of detecting malicious transactions. Hence, attacks caused by malicious transactions can be detected and canceled timely before they succeed

Higher Performance of QuantiFERON TB Compared to Tuberculin Skin Test in Latent Tuberculosis Infection Prospective Diagnosis

Background: The Tuberculin skin test (TST) has been used for years in the latent tuberculosis infection (LTBI) diagnosis, but it has, well-documented, low sensitivity and specificity. Interferon-ϒ release assays (IGRA) has been reported to be more sensitive and specific than TST. Therefore, this study aimed to evaluate the performance of a commercial IGRA, QuantiFERON®-TB Gold In-Tube (QFT-GIT), comparatively to TST in LTBI diagnosis. Patients and Methods: This study included 238 patients who were candidate for an anti-TNF therapy. The screening for LTBI was performed by both TST and QFT-GIT test for all patients. In order to evaluate the strength of associations, the odds ratios (OR) together with 95% confidence intervals (CI) were calculated. The correlation between QFT-GIT and TST was evaluated using κ statistics. Results: Sixty-three (26.4%) sera were positive for QFT-GIT with a mean level of IFN-ϒ of about 1.18 IU/ml, while 81 (34%) patients were positive for TST. Agreement between QFT-GIT and TST was poor (37 QFT-GIT+/TST- and 55 QFT-GIT-/TST+), κ=0.09 (SD=0.065). The positivity of QFT-GIT was not influenced by BCG vaccination or by immunosuppression. Nevertheless, it was significantly associated to both history of an earlier tuberculosis disease (HETD) and its radiological sequel (RS), p=6E-7 and p=1E-8, respectively. Inversely, the TST results were not correlated to either HETD or RS, but the TST positivity was less frequent in immunosuppressed patients (45.5% vs. 73.9%), p=1E-5, OR (95% CI) = 0.29 [0.17-0.52]. Moreover, the extent of both the immunosuppression period and the time elapsed from the last BCG injection was significantly correlated to a lesser TST positivity, p=3E-12 and p=5E-7, respectively. Among the QFT-GIT-/TST+ patients (n=55) whom received an anti-TNF agent without any prophylactic treatment of LTBI, no tuberculosis was detected with a median follow-up of 78 weeks [56-109]. Conclusion: Our study suggests that the QFT-GIT has a higher performance comparatively to TST in the LTBI screening that is unaffected by either BCG vaccination or immunosuppression. Therefore, IGRAs has to replace TST especially in patients who are under consideration for an anti-TNF therapy

Reparative radiological changes of hip joint after TNF inhibitors in ankylosing spondylitis

Background: Hip involvement in ankylosing spondylitis (AS) is a common extraspinal arthritic manifestation, which is associated to a worse functional outcome. Little data are available on the effectiveness of conservative treatment strategies. The TNF inhibitors have been proven effective on AS activity parameters. Their structural effect on hip disease however, little is studied. Case presentation: We describe four new cases of reparative changes of a damaged hip joint after treatment with TNF inhibitors. The average of age was 32.5 (27- 36) years. There were 3 men and 1 woman. Hip involvement was bilateral in all cases. Etanercept was prescribed in 3 cases and infliximab in 1 case. At baseline, all patients had a painful and limited hip with high disease activity and an important functional impairment. After an average of 5.5 years of treatment with TNF inhibitors, the BASRI hip evaluated in antero-posterior x-rays of the pelvis remained unchanged at 2.4. The average of mean hip joint space was 2.9mm (2.3-3.6). A widening in hip joint space was observed in all cases with less subchondral cysts. Conclusion: TNF inhibitors seem to be effective on hip joint disease in patients with AS

Lipid phosphate phosphatase 3 participates in transport carrier formation and protein trafficking in the early secretory pathway

The inhibition of phosphatidic acid phosphatase (PAP) activity by propanolol indicates that diacylglycerol (DAG) is required for the formation of transport carriers at the Golgi and for retrograde trafficking to the ER. Here we report that the PAP2 family member lipid phosphate phosphatase 3 (LPP3, also known as PAP2b) localizes in compartments of the secretory pathway from ER export sites to the Golgi complex. The depletion of human LPP3: (i) reduces the number of tubules generated from the ER-Golgi intermediate compartment and the Golgi, with those formed from the Golgi being longer in LPP3-silenced cells than in control cells; (ii) impairs the Rab6-dependent retrograde transport of Shiga toxin subunit B from the Golgi to the ER, but not the anterograde transport of VSV-G or ssDsRed; and (iii) induces a high accumulation of Golgi-associated membrane buds. LPP3 depletion also reduces levels of de novo synthesized DAG and the Golgi-associated DAG contents. Remarkably, overexpression of a catalytically inactive form of LPP3 mimics the effects of LPP3 knockdown on Rab6-dependent retrograde transport. We conclude that LPP3 participates in the formation of retrograde transport carriers at the ER-Golgi interface, where it transitorily cycles, and during its route to the plasma membrane