Identification of the SPG15 gene, encoding spastizin, as a frequent cause of complicated autosomal-recessive spastic paraplegia, including Kjellin syndrome

Hereditary spastic paraplegias (HSPs) are genetically and phenotypically heterogeneous disorders. Both "uncomplicated" and "complicated" forms have been described with various modes of inheritance. Sixteen loci for autosomal-recessive "complicated" HSP have been mapped. The SPG15 locus was first reported to account for a rare form of spastic paraplegia variably associated with mental impairment, pigmented maculopathy, dysarthria, cerebellar signs, and distal amyotrophy, sometimes designated as Kjellin syndrome. Here, we report the refinement of SPG15 to a 2.64 Mb genetic interval on chromosome 14q23.3-q24.2 and the identification of ZFYVE26, which encodes a zinc-finger protein with a FYVE domain that we named spastizin, as the cause of SPG15. Six different truncating mutations were found to segregate with the disease in eight families with a phenotype that included variable clinical features of Kjellin syndrome. ZFYVE26 mRNA was widely distributed in human tissues, as well as in rat embryos, suggesting a possible role of this gene during embryonic development. In the adult rodent brain, its expression profile closely resembled that of SPG11, another gene responsible for complicated HSP. In cultured cells, spastizin colocalized partially with markers of endoplasmic reticulum and endosomes, suggesting a role in intracellular trafficking.     

Characterization and properties of biosurfactants produced by a newly isolated strain <Emphasis Type="Italic">Bacillus methylotrophicus</Emphasis> DCS1 and their applications in enhancing solubility of hydrocarbon

Six biosurfactant-producing bacteria were isolated from hydrocarbon contaminated soils in Sfax, Tunisia. Isolates were screened for biosurfactant production by different conventional methods including hemolytic activity, surface tension reduction, drop-collapsing and oil displacement tests. All these screening tests show that all the isolates behave differently. Among the isolated bacteria, DCS1 strain was selected for further studies based on its highest activities and it was identified as Bacillus methylotrophicus DCS1. This strain was found to be a potent producer of biosurfactant when cultivated in mineral-salts medium supplemented with diesel oil (2 %, v/v) as a sole carbon source. Physicochemical properties and stability of biosurfactants synthesized by B. methylotrophicus DCS1 were investigated. The produced biosurfactants DCS1, from Landy medium, possess high surface activity that could lower the surface tension of water to a value of 31 from 72 mN m^?1 and have a critical micelle concentration (CMC) of 100 mg L^?1. Compared with SDS and Tween 80, biosurfactants showed excellent emulsification activities against different hydrocarbon substrates and high solubilization efficiency towards diesel oil. Biosurfactants DCS1 showed good stability in a wide range of temperature, pH and salinity. These results suggested that biosurfactants produced by B. methylotrophicus DCS1 could be an alternative to chemically synthesized surfactants for use in bioremediation processes to enhance the solubility of hydrophobic compounds.     

Inflammatory markers associated with abdominal aortic aneurysm

Purpose

Inflammation with leukocytic infiltration, degradation of extracellular matrix (ECM), and depletion of vascular smooth muscle cells (VSMC) are pathological hallmarks of abdominal aortic aneurysm (AAA). The aim of this study was to further evaluate relationships betweenAAAand inflammatory biomarkers, interleukin- 6 (IL-6), tumour necrosis factor-α (TNF-α), endothelin-1 (ET-1) and soluble urokinase-type plasminogen activator receptor (suPAR), by comparing levels in 65-year-old men with and without AAA at ultrasound screening.We also evaluated whether any biomarker can independently predict AAA at screening, and clarified potential correlations between aortic diameter and blood levels of these biomarkers.

Results

There were significant (p ? 0.05) differences between subjects with and without AAA for the following variables: p-leukocyte count (TLC) (p<0.001), p-homocysteine (p<0.001), p-TNF-α (p = 0.023), p-IL-6 (p<0.001), p-ET-1 (p = 0.002), p-suPAR (p<0.001), ankle brachial index (ABI) (p<0.001), plasma (p)-creatinine (p = 0.049), p-total cholesterol (p<0.001), p-high density lipoprotein (HDL) (p<0.001) and low density lipoprotein (LDL) cholesterol (p = 0.001), smoking habits (p<0.001), and use of antihypertensive (p<0.001) and lipid-lowering (p = 0.001) drugs. When the above variables were stepwise excluded in a logistic regression model, only p-IL-6 (p = 0.002), p-homocysteine (p = 0.015), p-HDL (p = 0.004), ABI in the right (p = 0.005) and left (p = 0.094) leg, smoking habits (p = 0.003), and antihypertensive drug use (p = 0.045), differed between groups. Significant correlations with aortic diameter existed for p-TNF-α (p = 0.028), p-IL-6 (p<0.001), p-ET-1 (p = 0.002) and p-suPAR (p<0.001) in the entire study population, and for p-TNF-α (p = 0.023), p-ET-1 (p = 0.009) and p-suPAR (p = 0.001) among men with AAA.

Conclusions

Several inflammatory biomarkers were significantly elevated and correlated with aortic diameter among 65-year old men with AAA at ultrasound screening. IL-6, homocysteine and use of antihypertensive medication remained elevated in the logistic regression model, together with known risk markers for AAA such as smoking and signs of atherosclerosis.

     

Long-term Exposure to Low Lithium Concentrations Stimulates Proliferation,Modifies Stress Protein Expression Pattern and Enhances Resistance to Oxidative Stress in SH-SY5Y Cells

SH-SY5Y cells, derived from a human neuroblastoma, were submitted to short- or long-term exposures to lithium carbonate concentrations ranging from 0.5 to 8 mM. Short-term exposures (4 days) to concentrations higher than 6 mM were found to reduce cell growth rate while exposure to 8 mM resulted in significant cell mortality. These ranges of concentrations induced an overexpression of (1) the HSP27 stress protein, (2) a 108 kDa protein (P108) recognized by an anti-phospho-HSP27(Ser78) antibody, and probably corresponding to a phosphorylated HSP27 tetramer, (3) a 105 kDa protein (P105), possible glycosylated or phosphorylated form of the GRP94 stress protein and (4) a phosphorylated (inactivated) form of glycogen synthase kinase (GSK3α/β) SH-SY5Y cells, when cultured in the presence of 0.5 mM lithium for 25 weeks, displayed interesting features as compared to controls: (1) higher cell growth rate, (2) increased resistance toward the inhibitory effects of high lithium concentrations on cell proliferation, (3) lower basal level of lipid peroxidation (TBARS) and improved tolerance to oxidative stress induced by high lithium concentrations, (5) reduced expression of monomeric HSP27 versus an increase of corresponding tetrameric protein (P108) and (6) overexpression of a 105 kDa protein (P105). In conclusion, our study suggests that chronic treatment (over several months) by therapeutic relevant lithium concentrations could favour neurogenesis, decrease the vulnerability of neuronal cells to oxidative stress and induce posttranslational changes of molecular chaperones.     

Chicken feathers: a complex substrate for the co-production of α-amylase and proteases by <Emphasis Type="Italic">B. licheniformis</Emphasis> NH1

This study is concerned with the co-production of alkaline proteases and thermostable α-amylase by some feather-degrading Bacillus strains: B. mojavensis A21, B. licheniformis NH1, B. subtilis A26, B. amyloliquefaciens An6 and B. pumilus A1. All strains produced both enzymes, except B. pumilus A1, which did not exhibit amylolytic activity. The best enzyme co-production was obtained by the NH1 strain when chicken feathers were used as nitrogen and carbon sources in the fermentation medium. The higher co-production of both enzymes by B. licheniformis NH1 strain was achieved in the presence of 7.5 g/l chicken feathers and 1 g/l yeast extract. Strong catabolic repression on protease and α-amylase production was observed with glucose. Addition of 0.5% glucose to the feather medium suppressed enzyme production by B. licheniformis NH1. The growth of B. licheniformis NH1 using chicken feathers as nitrogen and carbon sources resulted in its complete degradation after 24 h of incubation at 37°C. However, maximum protease and amylase activities were attained after 30 h and 48 h, respectively. Proteolytic activity profiles of NH1 enzymatic preparation grown on chicken feather or casein-based medium are different. As far as we know, this is the first contribution towards the co-production of α-amylase and proteases using keratinous waste. Strain NH1 shows potential use for biotechnological processes involving keratin hydrolysis and industrial α-amylase and proteases co-production. Thus, the utilization of chicken feathers may result in a cost-effective process suitable for large-scale production.     

Selective constraints, molecular recombination structure and phylogenetic reconstruction of isometric plant RNA viruses of the families Luteoviridae and Tymoviridae

In an effort to enhance the knowledge on molecular evolution of currently the known members of the families Luteoviridae and Tymoviridae, in-depth molecular investigations in the entire genome of 147 accessions retrieved from the international databases, were carried out. Two algorithms (RECCO and RDP version 3.31β) adapted to the mosaic structure of viruses were utilized. The recombination frequency along the sequences was dissected and demonstrated that the three virus genera of the family Luteoviridae comprise numerous members subjected to recombination. It has pointed out that the major viruses swapped a few but long genomic segments. In addition, in Barley yellow dwarf virus, heredity material might be exchanged between two different serotypes. Even more, putative recombination events occurred between two different genera. Based on Fisher’s Exact Test of Neutrality, positive selection acting on protein expression was detected only in the poleroviruses Cereal yellow dwarf virus, Potato leafroll virus and Wheat yellow dwarf virus. In contrast, several components of the family Tymoviridae were highly recombinant. Genomic portion exchange arose in many positions consisting of short fragments. Furthermore, no positive selection was detected. The evolutionary history showed, in the Luteoviridae, that all screened isolates split into three clusters corresponding to the three virus genera forming this family. Moreover, in the serotype PAV of Barley yellow dwarf virus, two major clades corresponding to PAV-USA and PAV-China, were delineated. Similarly, in the Tymoviridae, all analyzed isolates fell into four groups corresponding to the three virus genera composing this family along with the unclassified Tymoviridae. Inferred phylogenies reshuffled the existing classification and showed that Wheat yellow dwarf virus-RPV was genetically closely related to Cereal yellow dwarf virus and the unclassified Tymoviridae Grapevine syrah virus-1 constituted an integral part of the genus Marafivirus.     

Does the dysregulation of matrix metalloproteinases contribute to recurrent implantation failure?

Introduction: The progress in in vitro fertilization (IVF) techniques for infertility management has led to the investigation of embryo implantation site proteins such as Matrix metalloproteinases (MMPs), which may have a key role in embryo-endometrium crosstalk and in the molecular mechanisms of the embryo implantation.

Areas covered: Numerous studies have generated much information concerning the relation between the different proteins at the site of implantation such as cytokines, growth factors, adhesion molecules and MMPs. However, the exact role of the MMPs in embryo implantation and the impact of their dysregulation in recurrent implantation failure have yet to be characterized.

Expert commentary: The proteomic investigation of the MMPs and their molecular pathways may enable scientists and clinicians to correct this dysregulation (via appropriate means of prevention and treatment), better manage embryo transfer during IVF cycles, and thus increase the ongoing pregnancy rate.