Aberrant cardiolipin metabolism is associated with cognitive deficiency and hippocampal alteration in tafazzin knockdown mice

Cardiolipin (CL) is a key mitochondrial phospholipid essential for mitochondrial energy production. CL is remodeled from monolysocardiolipin (MLCL) by the enzyme tafazzin (TAZ). Loss-of-function mutations in the gene which encodes TAZ results in a rare X-linked disorder called Barth Syndrome (BTHS). The mutated TAZ is unable to maintain the physiological CL:MLCL ratio, thus reducing CL levels and affecting mitochondrial function. BTHS is best known as a cardiac disease, but has been acknowledged as a multi-syndrome disorder, including cognitive deficits. Since reduced CL levels has also been reported in numerous neurodegenerative disorders, we examined how TAZ-deficiency impacts cognitive abilities, brain mitochondrial respiration and the function of hippocampal neurons and glia in TAZ knockdown (TAZ kd) mice. We have identified for the first time the profile of changes that occur in brain phospholipid content and composition of TAZ kd mice. The brain of TAZ kd mice exhibited reduced TAZ protein expression, reduced total CL levels and a 19-fold accumulation of MLCL compared to wild-type littermate controls. TAZ kd brain exhibited a markedly distinct profile of CL and MLCL molecular species. In mitochondria, the activity of complex I was significantly elevated in the monomeric and supercomplex forms with TAZ-deficiency. This corresponded with elevated mitochondrial state I respiration and attenuated spare capacity. Furthermore, the production of reactive oxygen species was significantly elevated in TAZ kd brain mitochondria. While motor function remained normal in TAZ kd mice, they showed significant memory deficiency based on novel object recognition test. These results correlated with reduced synaptophysin protein levels and derangement of the neuronal CA1 layer in hippocampus. Finally, TAZ kd mice had elevated activation of brain immune cells, microglia compared to littermate controls. Collectively, our findings demonstrate that TAZ-mediated remodeling of CL contributes significantly to the expansive distribution of CL molecular species in the brain, plays a key role in mitochondria respiratory activity, maintains normal cognitive function, and identifies the hippocampus as a potential therapeutic target for BTHS.     

Investigate of AQP gene expression in the liver of mice after ischemia–reperfusion

Ischemia–reperfusion (IR) injury usually occurs during liver transplantation. Aquaporins (AQPs) are transmembrane channels that facilitate water permeability through cell membranes and are essential for the regulation of water homeostasis. Changes in the AQPs expression have been correlated with several inflammatory diseases. Less is known about AQPs expression in hepatic ischemia reperfusion injury. To clarify the roles of AQPs in IR injury, in this current study we examined the gene expression patterns of AQP1, 8 and 9 in the liver after IR injury. Male balb/c mice were exposed to partial (70%) hepatic ischemia for 65 min and then randomized into five groups of reperfusion [0 h (A), 8 h (B), 1 day (C), 3 days (D), and 7 days (E)]. A surgical group was also selected as the sham group. Serum and liver tissue samples were collected for evaluation of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and liver histopathology. Real time PCR was performed to evaluate the AQPs expression. I/R injury resulted in a significant increase in ALT and AST (p?<?0.05) compared to sham mice in each group. The gene expression of AQPs was significantly increased in the IR group compared with the sham group (p?<?0.05). AQP8 and AQP1 after 8 h (group B) showed the highest gene expression in comparison with other groups, but the highest level of AQP9 gene expression was observed after 1 day (group C). Pathologic changes in the liver after reperfusion were confirmed the IR. In the IR group cytoplasmic vacuolization, inflammatory cell infiltration and focal necrosis were detected. In conclusion, our findings indicated that the damage caused by ischemia–reperfusion in the liver can change the expression of AQP genes, which can interfere with hepatocellular homeostasis and their function. Upregulation of AQP1, 8 and 9 could contribute to the development of hepatocellular swelling after hepatic IR injury.     

Mucoralean fungi for sustainable production of bioethanol and biologically active molecules

Applied Microbiology and Biotechnology - Mucoralean fungi are suitable microorganisms for the sustainable production of food, fodder, and fuels from inexpensive natural resources. Ethanol-producing...     

Absence of a stable intermediate on the folding pathway of protein A.

The B-domain of protein A has one of the simplest protein topologies, a three-helix bundle. Its folding has been studied as a model for elementary steps in the folding of larger proteins. Earlier studies suggested that folding might occur by way of a helical hairpin intermediate. Equilibrium hydrogen exchange measurements indicate that the C-terminal helical hairpin could be a potential folding intermediate. Kinetic refolding experiments were performed using stopped-flow circular dichroism and NMR hydrogen-deuterium exchange pulse labeling. Folding of the entire molecule is essentially complete within the 6 ms dead time of the quench-flow apparatus, indicating that the intermediate, if formed, progresses rapidly to the final folded state. Site-directed mutagenesis of the isoleucine residue at position 16 was used to generate a variant protein containing tryptophan (the 116 W mutant). The formation of the putative folding intermediate was expected to be favored in this mutant at the expense of the native folded form, due to predicted unfavorable steric interactions of the bulky tryptophan side chain in the folded state. The 116 W mutant refolds completely within the dead time of a stopped-flow fluorescence experiment. No partly folded intermediate could be detected by either kinetic or equilibrium measurements. Studies of peptide fragments suggest that the protein A sequence has an intrinsic propensity to form a helix II/helix III hairpin. However, its stability appears to be marginal (of the order of 1/2 kT) and it could not be an obligatory intermediate on a defined folding pathway. These results explicitly demonstrate that the protein A B domain folds extremely rapidly by an apparent two-state mechanism without formation of stable partly folded intermediates. Similar mechanisms may also be involved in the rapid folding of subdomains of larger proteins to form the compact molten globule intermediates that often accumulate during the folding process.     

Nematodes as vectors to introduce Agrobacterium into plant roots

A fast plant promoter test was developed by means of a nematode to transfer Agrobacterium tumefaciens into plant roots. Two-week-old Arabidopsis thaliana (L.) Heynh. plants were transferred to infection medium. Meloidogyne incognita or Heterodera schachtii juveniles were mixed with the Agrobacterium strain that harboured the binary vector, and this mixture was used for plant inoculation. During migration of the nematode and establishment of the feeding site inside the roots, the T-DNA was delivered into the root cells. A few days later, the infected plants could be analysed for expression of the T-DNA reporter gene in and around the nematode feeding sites (NFS), without the need to go first through the whole transformation and regeneration procedure. Depending on the construct, expression of the β-glucuronidase gene in the NFS or along the migration path of the nematode could be seen in the roots of Arabidopsis plants. Furthermore, stably transformed plants could be regenerated from the infected roots.     

Identification and Characterization of two new Fungal Pathogens of Polygonatum odoratum (Angular Solomon's seal) in Italy

Polygonatum odoratum (Mill.) Druce (Angular Solomon's seal) is a well‐known ornamental plant and herbal drug, which is used in traditional medicine. Severe leaf spots were observed in wild Angular Solomon's seal plants in a public park in Trento, Italy. A combination of morphological and molecular characteristics, including sequence data of ITS‐rDNA, large subunit (LSU), beta tubulin (TUB) and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) led to identification of two species, namely Phoma odoratissimi and Colletotrichum dematium s. str., isolated from these leaf spots. Pathogenicity of the isolates was confirmed on wounded leaves of Po. odoratum; indeed, both species induced leaf spot symptoms on inoculated leaves within 10 days of inoculation. This is the first report of leaf spot disease caused by Ph. odoratissimi and C. dematium s. str. on Po. odoratum, which can be considered a new host for both the species examined in this study. In addition, isolation of Ph. odoratissimi represents a new record for the mycobiota of Italy.     

Interplay between SARS-CoV-2-derived miRNAs,immune system,vitamin D pathway and respiratory system

The new coronavirus pandemic started in China in 2019. The intensity of the disease can range from mild to severe, leading to death in many cases. Despite extensive research in this area, the exact molecular nature of virus is not fully recognized; however, according to pieces of evidence, one of the mechanisms of virus pathogenesis is through the function of viral miRNAs. So, we hypothesized that SARS-CoV-2 pathogenesis may be due to targeting important genes in the host with its miRNAs, which involved in the respiratory system, immune pathways and vitamin D pathways, thus possibly contributing to disease progression and virus survival. Potential miRNA precursors and mature miRNA were predicted and confirmed based on the virus genome. The next step was to predict and identify their target genes and perform functional enrichment analysis to recognize the biological processes connected with these genes in the three pathways mentioned above through several comprehensive databases. Finally, cis-acting regulatory elements in 5′ regulatory regions were analysed, and the analysis of available RNAseq data determined the expression level of genes. We revealed that thirty-nine mature miRNAs could theoretically derive from the SARS-CoV-2 genome. Functional enrichment analysis elucidated three highlighted pathways involved in SARS-CoV-2 pathogenesis: vitamin D, immune system and respiratory system. Our finding highlighted genes' involvement in three crucial molecular pathways and may help develop new therapeutic targets related to SARS-CoV-2.