Mitochondrial Formation Research Articles

Malate dehydrogenase: a story of diverse evolutionary radiation.

Malate dehydrogenase (MDH) is a ubiquitous enzyme involved in cellular respiration across all domains of life. MDH's ubiquity allows it to act as an excellent model for considering the history of life and how the rise of aerobic respiration and eukaryogenesis influenced this evolutionary process. Here, we present the diversity of the MDH family of enzymes across bacteria, archaea, and eukarya, the relationship between MDH and lactate dehydrogenase (LDH) in the formation of a protein superfamily, and the connections between MDH and endosymbiosis in the formation of mitochondria and chloroplasts. The development of novel and powerful DNA sequencing techniques has challenged some of the conventional wisdom underlying MDH evolution and suggests a history dominated by gene duplication, horizontal gene transfer, and cryptic endosymbiosis events and adaptation to a diverse range of environments across all domains of life over evolutionary time. The data also suggest a superfamily of proteins that do not share high levels of sequential similarity but yet retain strong conservation of core function via key amino acid residues and secondary structural components. As DNA sequencing and 'big data' analysis techniques continue to improve in the life sciences, it is likely that the story of MDH will continue to refine as more examples of superfamily diversity are recovered from nature and analyzed.

Mitochondrial membrane potential and oxidative stress interact to regulate Oma1-dependent processing of Opa1 and mitochondrial dynamics.

Mitochondrial form and function are regulated by the opposing forces of mitochondrial dynamics: fission and fusion. Mitochondrial dynamics are highly active and consequential during neuronal ischemia/reperfusion (I/R) injury. Mitochondrial fusion is executed at the mitochondrial inner membrane by Opa1. The balance of long (L-Opa1) and proteolytically cleaved short (S-Opa1) isoforms is critical for efficient fusion. Oma1 is the predominant stress-responsive protease for Opa1 processing. In neuronal cell models, we assessed Oma1 and Opa1 regulation during mitochondrial stress. In an immortalized mouse hippocampal neuron line (HT22), Oma1 was sensitive to mitochondrial membrane potential depolarization (rotenone, FCCP) and hyperpolarization (oligomycin). Further, oxidative stress was sufficient to increase Oma1 activity and necessary for depolarization-induced proteolysis. We generated Oma1 knockout (KO) HT22 cells that displayed normal mitochondrial morphology and fusion capabilities. FCCP-induced mitochondrial fragmentation was exacerbated in Oma1 KO cells. However, Oma1 KO cells were better equipped to perform restorative fusion after fragmentation, presumably due to preserved L-Opa1. We extended our investigations to a combinatorial stress of neuronal oxygen-glucose deprivation and reoxygenation (OGD/R), where we found that Opa1 processing and Oma1 activation were initiated during OGD in an ROS-dependent manner. These findings highlight a novel dependence of Oma1 on oxidative stress in response to depolarization. Further, we demonstrate contrasting fission/fusion roles for Oma1 in the acute response and recovery stages of mitochondrial stress. Collectively, our results add intersectionality and nuance to the previously proposed models of Oma1 activity.

Participation of the transcription factor CREB1 in the regulation of the Mdh2 gene encoding malate dehydrogenase in the liver of rats with alloxan diabetes

The aim of the study was to study the role of transcription factor CREB1 in regulating the expression of the gene encoding the mitochondrial form of malate dehydrogenase (MDH, EC 1.1.1.37) in the liver of rats with experimental diabetes. An increase in the rate of work of NAD-dependent malate dehydrogenase in rat liver cells during the development of experimental diabetes was shown, associated with the activation of the Mdh1 and Mdh2 genes encoding this enzyme. The analysis of the promoters of these genes showed that only in the Mdh2 gene there is a specific binding site with the transcription factor CREB1. It was found that in the liver of rats with pathology, there is an increase in the rate of expression of the gene encoding this transcription factor, which correlates with the expression of the Mdh2 gene. Thus, the data obtained by us confirm the possibility of positive regulation of the rate of the Mdh2 gene by the transcription factor CREB1.

Mitochondria- and ER-associated actin are required for mitochondrial fusion.

Mitochondria play a crucial role in the regulation of cellular metabolism and signalling. Mitochondrial activity is modulated by the processes of mitochondrial fission and fusion, which are required to properly balance respiratory and metabolic functions, transfer material between mitochondria, and remove defective mitochondria. Mitochondrial fission occurs at sites of contact between the endoplasmic reticulum (ER) and mitochondria, and is dependent on the formation of actin filaments that drive mitochondrial constriction and the recruitment and activation of the dynamin-related GTPase fission protein DRP1. The requirement for mitochondria- and ER-associated actin filaments in mitochondrial fission remains unclear, and the role of actin in mitochondrial fusion remains entirely unexplored. Here we show that preventing the formation of actin filaments on either mitochondria or the ER disrupts both mitochondrial fission and fusion. We show that fusion but not fission is dependent on Arp2/3, whereas both fission and fusion are dependent on INF2 formin-dependent actin polymerization. We also show that mitochondria-associated actin marks fusion sites prior to the dynamin family GTPase fusion protein MFN2. Together, our work introduces a novel method for perturbing organelle-associated actin filaments, and demonstrates a previously unknown role for actin in mitochondrial fusion.

High prevalence of m.1555A > G in patients with hearing loss in the Baikal Lake region of Russia as a result of founder effect

Mitochondrial forms account approximately 1–2% of all nonsyndromic cases of hearing loss (HL). One of the most common causative variants of mtDNA is the m.1555A > G variant of the MT-RNR1 gene (OMIM 561000). Currently the detection of the m.1555A > G variant of the MT-RNR1 gene is not included in all research protocols. In this study this variant was screened among 165 patients with HL from the Republic of Buryatia, located in the Baikal Lake region of Russia. In our study, the total contribution of the m.1555A > G variant to the etiology of HL was 12.7% (21/165), while the update global prevalence of this variant is 1.8% (863/47,328). The m.1555A > G variant was notably more prevalent in Buryat (20.2%) than in Russian patients (1.3%). Mitogenome analysis in 14 unrelated Buryat families carrying the m.1555A > G variant revealed a predominant lineage: in 13 families, a cluster affiliated with sub-haplogroup A5b (92.9%) was identified, while one family had the D5a2a1 lineage (7.1%). In a Russian family with the m.1555A > G variant the lineage affiliated with sub-haplogroup F1a1d was found. Considering that more than 90% of Buryat families with the m.1555A > G variant belong to the single maternal lineage cluster we conclude that high prevalence of this variant in patients with HL in the Baikal Lake region can be attributed to a founder effect.

Ascorbate-glutathione cycle in wheat and rice seedlings under anoxia and subsequent reaeration.

The most important part of the plant antioxidant system is the ascorbate-glutathione cycle (AGC), the activity of which is observed upon exposure to a range of stressors, including lack of O2, and oxidative stress occurring immediately after the restoration of oxygen access, hereafter termed reaeration or post-anoxia. The operation of the AGC (enzymes and low-molecular components) in wheat (Triticum aestivum, cv. Leningradka, non-resistant to hypoxia) and rice (Oryza sativa, cv. Liman, resistant) seedlings after 24 h anoxia and 1 h or 24 h reaeration was studied. Significant accumulation of oxidized forms of ascorbate and glutathione was revealed in the non-resistant plant (wheat) after 24 h of anoxia and reaeration, indicating the development of oxidative stress. In the resistant plant (rice), reduced forms of these antioxidants prevailed both in normoxia and under stress, which may indicate their intensive reduction. In wheat, the activities of ascorbate peroxidase and dehydroascorbate reductase in shoots, and monodehydroascorbate reductase and glutathione reductase in roots decreased under anoxia and reaeration. The activity of antioxidant enzymes was maintained in rice under lack of oxygen (ascorbate peroxidase, glutathione reductase) and increased during post-anoxia (AGC reductases). Anoxia stimulated accumulation of mRNA of the organellar ascorbate peroxidase genes OsAPX3, OsAPX5 in shoots, and OsAPX3-5 and OsAPX7 in roots. At post-anoxia, the contribution of the OsAPX1 and OsAPX2 genes encoding the cytosolic forms of the enzyme increased in the whole plant, and so did that of the OsAPX8 gene for the plastid form of the enzyme. The accumulation of mRNA of the genes OsMDAR2 and OsMDAR4 encoding peroxisomal and cytosolic monodehydroascorbate reductase as well as the OsGR2 and OsGR3 for cytosolic and organellar glutathione reductase was activated during reaeration in shoots and roots. In most cases, O2 deficiency activated the genes encoding the peroxisomal, plastid, and mitochondrial forms of the enzymes, and upon reaeration, an enhanced activity of the genes encoding the cytoplasmic forms was observed. Taken together, the inactivation of AGC enzymes was revealed in wheat seedlings during anoxia and subsequent reaeration, which disrupted the effective operation of the cycle and triggered the accumulation of oxidized forms of ascorbate and glutathione. In rice, anoxia led to the maintenance of the activity of AGC enzymes, and reaeration stimulated it, including at the level of gene expression, which ensured the effective operation of AGC.

Challenges Facing Us in DNA Analysis from Human Hair Samples: A Review

Human hair is a valuable tool in criminology, aiding in population studies through statistics and DNA analysis. It's easily identifiable at crime scenes, often clinging to clothing, carpets, and various surfaces, including animal fur, through a process known as secondary transfer. Forensic analysis of hair evidence serves several purposes; it can help establish the possibility of a connection between a suspect and a crime scene or between a suspect and a victim. It can demonstrate that there is no evidence linking the perpetrator to the crime scene or the suspect to the victim. While microscopic hair analysis cannot definitively identify a specific individual as the source of the hair, it does provide a solid basis for association. The wealth of macroscopic and microscopic details available in hair examination can also provide strong evidence for the defense. To understand the challenges of conducting DNA tests on hair, it's essential to study hair structure and composition. DNA in hair is not evenly distributed throughout every part of the hair; it exists in both nuclear and mitochondrial forms.

The regulation of the apoptotic pore-An immunological tightrope walk.

Apoptotic pore formation in mitochondria is the pivotal point for cell death during mitochondrial apoptosis. It is regulated by BCL-2 family proteins in response to various cellular stress triggers and mediates mitochondrial outer membrane permeabilization (MOMP). This allows the release of mitochondrial contents into the cytosol, which triggers rapid cell death and clearance through the activation of caspases. However, under conditions of low caspase activity, the mitochondrial contents released into the cytosol through apoptotic pores serve as inflammatory signals and activate various inflammatory responses. In this chapter, we discuss how the formation of the apoptotic pore is regulated by BCL-2 proteins as well as other cellular or mitochondrial proteins and membrane lipids. Moreover, we highlight the importance of sublethal MOMP in the regulation of mitochondrial-activated inflammation and discuss its physiological consequences in the context of pathogen infection and disease and how it can potentially be exploited therapeutically, for example to improve cancer treatment.

Subcellular expression of CYP2E1 in HepG2 cells impacts response to free oleic and palmitic acid

AimsCytochrome P450 2E1 (CYP2E1) is a mammalian monooxygenase expressed at high levels in the liver that metabolizes low molecular weight pollutants and drugs, as well as endogenous fatty acids and ketones. Although CYP2E1 has been mainly studied in the endoplasmic reticulum (ER, microsomal fraction), it also localizes in significant amounts to the mitochondria, where it has been far less studied. We investigated the effects of CYP2E1 expression in mitochondria, endoplasmic reticulum, or both organelles in transgenic HepG2 cells exposed to free oleic and palmitic acid, including effects on cytotoxicity, lipid storage, respiration, and gene expression. ResultsWe found that HepG2 cells expressing CYP2E1 in both the ER and mitochondria have exacerbated levels of palmitic acid cytotoxicity and inhibited respiration. CYP2E1 expression did not impact lipid accumulation from fatty acid exposures, but mitochondrial CYP2E1 expression promoted lipid droplet depletion during serum starvation. In contrast to HepG2 cells, differentiated HepaRG cells express abundant CYP2E1, but they are not sensitive to palmitic acid cytotoxicity. Oleic acid exposure prompted less cytotoxicity, and CYP2E1 expression in the ER prevented an oleic-acid-induced increase in respiration. HepG2 cells exposed to mixtures of palmitic and oleic acid are protected from palmitic acid cytotoxicity. Additionally, we identified that CYP2E1 was decreased at the gene and protein level in hepatocellular carcinoma. Moreover, patients with tumors that had higher CYP2E1 expression had a better prognosis compared to patients with lower CYP2E1 expression. InnovationThis study has demonstrated that transgenic CYP2E1 subcellular localization plays an important role in sensitivity to cytotoxicity, lipid storage, and respiration in the hepatoma cell line HepG2 exposed to palmitic and oleic acid. HepaRG cells, in contrast, were insensitive to palmitic acid. This work demonstrates the clear importance of CYP2E1 in dictating lipotoxicity and differential roles for the mitochondrial and ER forms of the enzyme. Additionally, our data supports a potentially unique role for CYP2E1 in cancer cells. ConclusionThere lies a role for CYP2E1 in altering lipotoxicity, and since CYP2E1 is known to be upregulated in both liver disease and hepatocellular carcinoma, it is important to better define how the role of CYP2E1 changes during disease progression.

DNAJC30 Gene Variants Are a Frequent Cause of a Rare Disease: Leber Hereditary Optic Neuropathy in Polish Patients.

Leber hereditary optic neuropathy (LHON) is a rare disorder causing a sudden painless loss of visual acuity in one or both eyes, affecting young males in their second to third decade of life. The molecular background of the LHON is up to 90%, genetically defined by a point mutation in mitochondrial DNA. Recently, an autosomal recessive form of LHON (LHONAR1, arLHON) has been discovered, caused by biallelic variants in the DNAJC30 gene. This study provides the results of the DNAJC30 gene analysis in a large group of 46 Polish patients diagnosed with LHON, together with the clinical characterization of the disease. The c.152A>G (p.Tyr51Cys) substitution in the DNAJC30 gene was detected in all the patients as homozygote or compound heterozygote. Moreover, we identified one novel variant, c.293A>G, p.(Tyr98Cys), as well as two ultra-rare DNAJC30 variants: c.293A>C, p.(Tyr98Ser), identified to date only in one individual affected with LHONAR1, and c.130_131delTC (p.Ser44ValfsTer8), previously described only in two patients with Leigh syndrome. The patients presented here represent the largest group of subjects with DNAJC30 gene mutations described to date. Based on our data, the autosomal recessive form of LHON caused by DNAJC30 gene mutations is more frequent than the mitochondrial form in Polish patients. The results of our study suggest that Sanger sequencing of the single-exon DNAJC30 gene should be a method of choice applied to identify a molecular background of clinically confirmed LHON in Polish patients. This approach will help to reduce the costs of molecular testing.

Fundamental role for the creatine kinase pathway in protection from murine colitis

Inflammatory diseases of the digestive tract, including inflammatory bowel disease, cause metabolic stress within mucosal tissue. Creatine is a key energetic regulator. We previously reported a loss of creatine kinases (CKs) and the creatine transporter expression in inflammatory bowel disease patient intestinal biopsy samples and that creatine supplementation was protective in a dextran sulfate sodium (DSS) colitis mouse model. In the present studies, we evaluated the role of CK loss in active inflammation using the DSS colitis model. Mice lacking expression of CK brain type/CK mitochondrial form (CKdKO) showed increased susceptibility to DSS colitis (weight loss, disease activity, permeability, colon length, and histology). In a broad cytokine profiling, CKdKO mice expressed near absent interferon gamma (IFN-γ) levels. We identified losses in IFN-γ production from CD4+ and CD8+ T cells isolated from CKdKO mice. Addback of IFN-γ during DSS treatment resulted in partial protection for CKdKO mice. Extensions of these studies identified basal stabilization of the transcription factor hypoxia-inducible factor in CKdKO splenocytes and pharmacological stabilization of hypoxia-inducible factor resulted in reduced IFN-γ production by control splenocytes. Thus, the loss of IFN-γ production by CD4+ and CD8+ T cells in CKdKO mice resulted in increased colitis susceptibility and indicates that CK is protective in active mucosal inflammation.

94-OR: Myeloid-Specific ERa Deletion Disrupts Mitochondrial Function Driving Iron Accumulation and Cardiometabolic Disease

Sex differences in metabolism and cardiometabolic disease risk are well described. Because estrogen action is thought to underlie female-biased protection of immunometabolism and cardiometabolic health, we selectively deleted the estrogen receptor alpha (ERa, encoded by Esr1) from myeloid cells of mice to understand the impact of estrogen action on macrophage function. Our previous findings in other glucoregulatory cell types point to an important role of ERa in the control of mitochondrial form and function. Mitochondria play a critical role in innate immunity, and disruption of mitochondrial function is linked to the pathogenesis of cardiometabolic disease. In addition to a primary role in energy production, mitochondria are central in the regulation of iron homeostasis, a critical process governing immune cell function. Myeloid-specific Esr1 knockout mice (MACER) showed increased diet-induced glucose intolerance, insulin resistance, adiposity, and atherosclerotic lesion area compared with f/f controls. A key phenotype of MACER mice was marked accumulation of iron in liver, spleen, gonadal white adipose tissue, and bone marrow-derived macrophages compared with f/f controls. Specifically, iron accumulated in mitochondria from macrophages within tissues of MACER mice. Iron accumulation was linked with alteration of mitochondrial inner and outer membrane morphology and mtDNA replication machinery, and associated with increased transferrin receptor (Tfrc) expression and cellular inflammation driven by interleukin-1-β. We utilized chromatin immunoprecipitation approaches to identify novel ERa-regulated chromatin structures and target genes that modulate immunometabolism of macrophages. Our findings indicate that Esr1 is critical in the regulation of mitochondrial metabolism and iron homeostasis in macrophages, and the action of ERa is critical for the protection against inflammation and cardiometabolic-related disease. Disclosure H.Iwasaki: None. B.K.Leyva: None. A.Ma: None. N.L.Yang: None. P.H.Tran: None. Z.Zhou: None. A.L.Hevener: None. Funding National Institutes of Health (DK128957)

Light-Dependent Expression and Promoter Methylation of the Genes Encoding Succinate Dehydrogenase, Fumarase, and NAD-Malate Dehydrogenase in Maize (Zea mays L.) Leaves.

The expression and methylation of promoters of the genes encoding succinate dehydrogenase, fumarase, and NAD-malate dehydrogenase in maize (Zea mays L.) leaves depending on the light regime were studied. The genes encoding the catalytic subunits of succinate dehydrogenase showed suppression of expression upon irradiation by red light, which was abolished by far-red light. This was accompanied by an increase in promoter methylation of the gene Sdh1-2 encoding the flavoprotein subunit A, while methylation was low for Sdh2-3 encoding the iron-sulfur subunit B under all conditions. The expression of Sdh3-1 and Sdh4 encoding the anchoring subunits C and D was not affected by red light. The expression of Fum1 encoding the mitochondrial form of fumarase was regulated by red and far-red light via methylation of its promoter. Only one gene encoding the mitochondrial NAD-malate dehydrogenase gene (mMdh1) was regulated by red and far-red light, while the second gene (mMdh2) did not respond to irradiation, and neither gene was controlled by promoter methylation. It is concluded that the dicarboxylic branch of the tricarboxylic acid cycle is regulated by light via the phytochrome mechanism, and promoter methylation is involved with the flavoprotein subunit of succinate dehydrogenase and the mitochondrial fumarase.

Patient's dermal fibroblasts as disease markers for visceral myopathy.

Visceral myopathy (VSCM) is a rare genetic disease, orphan of pharmacological therapy. VSCM diagnosis is not always straightforward due to symptomatology similarities with mitochondrial or neuronal forms of intestinal pseudo-obstruction. The most prevalent form of VSCM is associates with variants in the gene ACTG2, encoding the protein gamma-2 actin. Overall, VSCM is a mechano-biological disorder, in which different genetic variants lead to similar alterations to the contractile phenotype of enteric smooth muscles, resulting in the emergence of life-threatening symptoms. In this work we analyzed the morpho-mechanical phenotype of human dermal fibroblasts from patients affected with VSCM, demonstrating that they retain a clear signature of the disease when compared with different controls. We evaluated several biophysical traits of fibroblasts, and we show that a measure of cellular traction forces can be used as a non-specific biomarker of the disease. We propose that a simple assay based on traction forces could be designed to provide a valuable support for clinical decision or pre-clinical research.

OVERLOAD-INDUCED EXTRACELLULAR MITOCHONDRIA RELEASING FROM TENDON ORGANOID LEADS TO INFLAMMATION

Tendinopathy is the most frequent musculoskeletal disease that requires medical attention. Mechanical overload has been considered as a key driver of its pathology. However, the underline mechanism on how overload induces tendinopathy and inflammation is unclear. Extracellular mitochondria (EM) are newly identified as cell-to-cell communicators. The aim of this study is to elucidate the role of mitochondria in overload-induced inflammation.We performed three-dimensional uniaxial stretching to mouse tendon organoid in bioreactors. Cyclic strain of uniaxial loadings included underload, normal load, and overload, according to previous work. We then harvested microvesicles including EM, from the bioreactor by differential centrifugation and evaluated their characteristics by flow cytometry and super-resolution confocal microscopy. Raw 264.7 mouse macrophage cell line was used for chemotaxis assay in a Boyden Chamber System with Magnetic-Activated Cell Sorting Technology. EM induced cytokines secretion by macrophages was analyzed by a bead-based multiplex assay panel. N-Acetyl-L-cysteine (NAC) was used as the antioxidant to tendon organoid to regulate mitochondrial fitness.We showed mechanical load induced tendon organoid to release microvesicles including mitochondria. The size of microvesicles is mainly in the range from 220nm to 880nm. More than 75% of microvesicles could be stained by PKH26, confirming they were with lipophilic membrane. Super-resolution confocal microscopy identified two forms of mitochondria, including mitochondria encapsulated in vesicles and free mitochondria. Overload led to the degeneration of the organoid and induced microvesicles release containing most EM. Chemotaxis assay showed that EM from overloaded tendon organoid induced macrophages chemotaxis. In addition, microvesicles extracted from overloaded tendon organoid induced the production of proinflammatory cytokines including IL-6, KC (Keratinocyte-Derived Chemokine) and IL-18. NAC treatment to tendon cells could attenuate overload-induced macrophage chemotaxis.Overload induces EM releasing from tendon cells, which leads to chemotaxis of macrophages toward tendon, resulting in induction of inflammation.

Biallelic pathogenic variants in the mitochondrial form of phosphoenolpyruvate carboxykinase cause peripheral neuropathy.

Phosphoenolpyruvate carboxykinase (PCK) plays a critical role in cytosolic gluconeogenesis, and defects in PCK1 cause a fasting-aggravated metabolic disease with hypoglycemia and lactic acidosis. However, there are two genes encoding PCK, and the role of the mitochondrial resident PCK (encoded by PCK2) is unclear, since gluconeogenesis is cytosolic. We identified three patients in two families with biallelic variants in PCK2. One has compound heterozygous variants (p.Ser23Ter/p.Pro170Leu), and the other two (siblings) have homozygous p.Arg193Ter variation. All three patients have weakness and abnormal gait, an absence of PCK2 protein, and profound reduction in PCK2 activity in fibroblasts, but no obvious metabolic phenotype. Nerve conduction studies showed reduced conduction velocities with temporal dispersion and conduction block compatible with a demyelinating peripheral neuropathy. To validate the association between PCK2 variants and clinical disease, we generated a mouse knockout model of PCK2 deficiency. The animals present abnormal nerve conduction studies and peripheral nerve pathology, corroborating the human phenotype. In total, we conclude that biallelic variants in PCK2 cause a neurogenetic disorder featuring abnormal gait and peripheral neuropathy.

Depletion and Repletion of Biotinyl Enzymes in Liver of Biotin-Deficient Rats: Evidence of a Biotin Storage System

The quantities of biotinyl proteins in liver of young rats were compared with age-matched controls at intervals during depletion and repletion of biotin. Growth rate and the concentrations of biotinyl proteins previously proposed as mitochondrial storage forms of acetyl CoA carboxylase rapidly decreased in response to biotin deprivation, whereas neither the concentration nor activity of cytosolic acetyl CoA carboxylase was affected. Concentrations of carboxylases active within mitochondria (pyruvate carboxylase, propionyl CoA carboxylase and 3-methyl crotonyl CoA carboxylase) decreased only after d 28. When biotin was injected into biotin-deficient rats, concentrations of the carboxylases active within mitochondria were restored to control levels within 3 h, whereas the concentrations of putative mitochondrial storage forms of acetyl CoA carboxylase reached normal levels only after 9 h, indicating that the injected biotin was preferentially used for the synthesis of the carboxylases active within mitochondria rather than acetyl CoA carboxylase. Mitochondrial acetyl CoA carboxylase may serve as a reservoir to maintain a normal concentration of cytosolic acetyl CoA carboxylase in liver of rats deprived of biotin and provide biotin, indirectly, to maintain essentially normal concentrations of the biotinyl enzymes active within mitochondria for several weeks after rats were fed a biotin-deficient diet.

Comprehensive analysis of the complete mitochondrial genome ofMelanoplus differentialis(Acrididae: Melanoplinae) captured in Korea

AbstractIn this study, we determined the complete mitochondrial genome of the invasive insect speciesMelanoplus differentialiscaptured in Korea. The complete mitochondrial genome ofM. differentialisis 15,625 bp long and comprises 13 protein‐coding genes, two ribosomal RNA genes, and 22 transfer RNAs, with a GC ratio of 25.2%. In total, 353 SNPs and 11 INDEL regions (total length 67 bp) were found against the previously sequencedM. differentialismitochondrial genome recorded as public genome data. The number of interspecific variations was greater than the number of intraspecific variations in this insect. Phylogenetic tree analysis showed that the mitochondrial genome clustered theMelanoplusclade with two previously reportedMelanoplussequences. However, the sequences were not divided at the species‐level clade possibly as a consequence of misidentification caused by an error in the public database. Our results extend the molecular database status ofMelanoplusby providing a novel complete mitochondrial genome sequence forM. differentialisthat could serve as reference for further molecular studies.

Evaluation of Thiol-Disulfide Homeostasis with Electrical Status Epilepticus in Slow Sleep (ESES).

Electrical status epilepticus in sleep (ESES) is an epileptic syndrome specific to childhood and has a broad clinical spectrum that included seizures, behavioral/cognitive impairments, and motor neurological symptoms. Antioxidants are seen as promising neuroprotective strategies for the epileptic state by combating the harmful effects of excessive oxidant formation in mitochondria. This study aims to evaluate the thiol-disulfide balance and to determine whether it can be used in the clinical and electrophysiological follow-up of patients with ESES, especially in addition to the electroencephalography (EEG) examination. The study included 30 patients, aged 2-18 years and diagnosed with ESES in the Pediatric Neurology Clinic of the Training and Research Hospital and a control group of 30 healthy children. Total thiol, native thiol, disulfide, and ischemia-modified albumin (IMA) levels were measured, and disulfide-thiol ratios were calculated for both groups. Native thiol and total thiol levels were significantly lower and IMA level and disulfide-native thiol percentage ratio were significantly higher in the ESES patient group than in the control group. Serum thiol-disulfide homeostasis is an accurate marker of oxidative stress in ESES, and standard and automated measures of thiol-disulfide balance as an indicator of oxidative stress showed a shift toward oxidation in ESES patients in this study. The negative correlation between spike-wave index (SWI) and thiol levels, and serum thiol-disulfide levels suggest that they can be used as biomarkers for follow-up of patients with ESES in addition to EEG. IMA can also be used for long-term response to monitoring purposes at ESES.

Formation of protein-mediated bilayer tubes is governed by a snapthrough transition.

Plasma membrane tubes are ubiquitous in cellular membranes and in the membranes of intracellular organelles. They play crucial roles in trafficking, ion transport, and cellular motility. These tubes can be formed due to localized forces acting on the membrane or by the curvature induced by membrane-bound proteins. Here, we present a mathematical framework to model cylindrical tubular protrusions formed by proteins that induce anisotropic spontaneous curvature. Our analysis revealed that the tube radius depends on an effective tension that includes contributions from the bare membrane tension and the protein-induced curvature. We also found that the length of the tube undergoes an abrupt transition from a short, dome-shaped membrane to a long cylinder and this transition is characteristic of a snapthrough instability. Finally, we show that the snapthrough instability depends on the different parameters including coat area, bending modulus, and extent of protein-induced curvature. Our findings have implications for tube formation due to BAR-domain proteins in processes such as endocytosis, t-tubule formation in myocytes, and cristae formation in mitochondria.