Knockout of the folate transporter folt-1 causes germline and somatic defects in C. elegans

<p>Abstract</p> <p>Background</p> <p>The <it>C. elegans </it>gene <it>folt-1 </it>is an ortholog of the human reduced folate carrier gene. The FOLT-1 protein has been shown to transport folate and to be involved in uptake of exogenous folate by worms. A knockout mutation of the gene, <it>folt-1(ok1460)</it>, was shown to cause sterility, and here we investigate the source of the sterility and the effect of the <it>folt-1 </it>knockout on somatic function.</p> <p>Results</p> <p>Our results show that <it>folt-1(ok1460) </it>knockout hermaphrodites have a substantially reduced germline, generate a small number of functional sperm, and only rarely produce a functional oocyte. We found no evidence of increased apoptosis in the germline of <it>folt-1 </it>knockout mutants, suggesting that germline proliferation is defective. While <it>folt-1 </it>knockout males are fertile, their rate of spermatogenesis was severely diminished, and the males were very poor maters. The mating defect is likely due to compromised metabolism and/or other somatic functions, as <it>folt-1 </it>knockout hermaphrodites displayed a shortened lifespan and elongated defecation intervals.</p> <p>Conclusions</p> <p>The FOLT-1 protein function affects both the soma and the germline. <it>folt-1(ok1460) </it>hermaphrodites suffer severely diminished lifespan and germline defects that result in sterility. Germline defects associated with folate deficiency appear widespread in animals, being found in humans, mice, fruit flies, and here, nematodes.</p

Biofilm Engineering Approaches for Improving the Performance of Microbial Fuel Cells and Bioelectrochemical Systems

Microbial fuel cells (MFCs) are emerging as a promising future technology for a wide range of applications in addition to sustainable electricity generation. Electroactive (EA) biofilms produced by microorganisms are the key players in the bioelectrochemical systems involving microorganism mediated electrocatalytic reactions. Therefore, genetically modifying the organism for increased production of EA biofilms and improving the extra electron transfer (EET) mechanisms may attribute to increase in current density of a MFC and an increased COD removal in wastewater treatment plant coupled MFC systems. Extracellular polysaccharides (EPS) produced by the organisms attribute to both biofilm formation and electron transfer. Although cell surface modification, media optimization and operation parameters validation are established as enhancement strategies for a fuel cell performance, engineering the vital genes involved in electroactive biofilm formation is the future hope. Therefore, in this review we critically address the biofilm formation mechanisms in electro active microorganisms, strategies for improving the biofilm formation leading to improved electrocatalytic rates for applications in bioelectrochemical systems

Clinical, pathological and functional characterization of riboflavin-responsive neuropathy.

Brown-Vialetto-Van Laere syndrome represents a phenotypic spectrum of motor, sensory, and cranial nerve neuropathy, often with ataxia, optic atrophy and respiratory problems leading to ventilator-dependence. Loss-of-function mutations in two riboflavin transporter genes, SLC52A2 and SLC52A3, have recently been linked to Brown-Vialetto-Van Laere syndrome. However, the genetic frequency, neuropathology and downstream consequences of riboflavin transporter mutations are unclear. By screening a large cohort of 132 patients with early-onset severe sensory, motor and cranial nerve neuropathy we confirmed the strong genetic link between riboflavin transporter mutations and Brown-Vialetto-Van Laere syndrome, identifying 22 pathogenic mutations in SLC52A2 and SLC52A3, 14 of which were novel. Brain and spinal cord neuropathological examination of two cases with SLC52A3 mutations showed classical symmetrical brainstem lesions resembling pathology seen in mitochondrial disease, including severe neuronal loss in the lower cranial nerve nuclei, anterior horns and corresponding nerves, atrophy of the spinothalamic and spinocerebellar tracts and posterior column-medial lemniscus pathways. Mitochondrial dysfunction has previously been implicated in an array of neurodegenerative disorders. Since riboflavin metabolites are critical components of the mitochondrial electron transport chain, we hypothesized that reduced riboflavin transport would result in impaired mitochondrial activity, and confirmed this using in vitro and in vivo models. Electron transport chain complex I and complex II activity were decreased in SLC52A2 patient fibroblasts, while global knockdown of the single Drosophila melanogaster riboflavin transporter homologue revealed reduced levels of riboflavin, downstream metabolites, and electron transport chain complex I activity. This in turn led to abnormal mitochondrial membrane potential, respiratory chain activity and morphology. Riboflavin transporter knockdown in Drosophila also resulted in severely impaired locomotor activity and reduced lifespan, mirroring patient pathology, and these phenotypes could be partially rescued using a novel esterified derivative of riboflavin. Our findings expand the genetic, clinical and neuropathological features of Brown-Vialetto-Van Laere syndrome, implicate mitochondrial dysfunction as a downstream consequence of riboflavin transporter gene defects, and validate riboflavin esters as a potential therapeutic strategy

Pathogenic UNC13A variants cause a neurodevelopmental syndrome by impairing synaptic function

The UNC13A gene encodes a presynaptic protein that is crucial for setting the strength and dynamics of information transfer between neurons. Here we describe a neurodevelopmental syndrome caused by germline coding or splice-site variants in UNC13A. The syndrome presents with variable degrees of developmental delay and intellectual disability, seizures of different types, tremor and dyskinetic movements and, in some cases, death in early childhood. Using assays with expression of UNC13A variants in mouse hippocampal neurons and in Caenorhabditis elegans, we identify three mechanisms of pathogenicity, including reduction in synaptic strength caused by reduced UNC13A protein expression, increased neurotransmission caused by UNC13A gain-of-function and impaired regulation of neurotransmission by second messenger signalling. Based on a strong genotype-phenotype-functional correlation, we classify three UNC13A syndrome subtypes (types A-C). We conclude that the precise regulation of neurotransmitter release by UNC13A is critical for human nervous system function

β-fructofuranosidase production by 2-deoxyglucose resistant mutants of <i><span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">Aspergillus niger </span></i><span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">in submerged and solid-state fermentation</span>

1032-1037<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">Aspergillus niger <span style="font-size:14.0pt;line-height:115%; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">produces extracellular β-fructofuranosidase under submerged (SmF) and solid state fermentation(SSF) conditions. After UV mutagenesis of conidiospores of A. <i style="mso-bidi-font-style: normal">niger, 2-deoxyglucose (10 g/l) resistant mutants were isolated on Czapek's minimal medium containing glycerol as a carbon source and the mutants were examined for improved production of β-fructofuranosidase in SmF and SSF conditions. One of such mutant DGRA-1 overproduced β-fructofuanosidase in both SmF and SSF conditions. In SmF, the mutant DGRA- 1 showed higher β- fructofuranosidase productivity (110.8 U/1/hr) than the wild type (48.3 U/I/hr). While in SSF the same strain produced 322 U/1/hr of β fructofuranosidase,2 times higher than that of wild type (154.2 U/1/ hr). In SmF, both wildtype and mutants produced relatively low level of β-fructofuranosidase in medium containing sucrose with glucose than from the sucrose medium. However in SSF, the DGRA- 1 mutant grown in sucrose and sucrose + glucose did not show any difference with respect to β-fructofuranosidase production. These results indicate that the catabolite repression of β- fructofuranosidase synthesis is observed in SmF whereas in SSF such regulation was not prominent.</span

Phlorotannins from Brown Algae: inhibition of advanced glycation end products formation in high glucose induced <i style="mso-bidi-font-style:normal">Caenorhabditis elegans</i>

371-379Advanced Glycation End products (AGE) generated in a non enzymatic protein glycation process are frequently associated with diabetes, aging and other chronic diseases. Here, we explored the protective effect of phlorotannins from brown algae Padina pavonica, Sargassum polycystum and Turbinaria ornata against AGEs formation. Phlorotannins were extracted from brown algae with methanol and its purity was analyzed by TLC and RP-HPLC-DAD. Twenty five grams of P. pavonica, S. polycystum, T. ornata yielded 27.6±0.8 µg/ml, 37.7 µg/ml and 37.1±0.74 µg/ml of phloroglucinol equivalent of phlorotannins, respectively. Antioxidant potentials were examined through DPPH assay and their IC50 values were P. pavonica (30.12±0.99 µg), S. polycystum (40.9±1.2 µg) and T. ornata (22.9±1.3 µg), which was comparatively lesser than the control ascorbic acid (46±0.2 µg). Further, anti-AGE activity was examined in vitro by BSA-glucose assay with the extracted phlorotannins of brown algae (P. pavonica, 15.16±0.26 µg/ml; S. polycystum, 35.245±2.3 µg/ml; T. ornata,<i style="mso-bidi-font-style: normal"> 22.7±0.3 µg/ml), which revealed the required concentration to inhibit 50% of albumin glycation (IC50) were lower for extracts than controls (phloroglucinol, 222.33±4.9 µg/ml; thiamine, 263 µg/ml). Furthermore, brown algal extracts containing phlorotannins (100 µl) exhibited protective effects against AGE formation <i style="mso-bidi-font-style: normal">in vivo in C. elegans with induced hyperglycemia.<span style="mso-bidi-font-family: GCFrutiger-Bold" lang="EN-GB"> </span