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Bromelain is an effective chemoresponsive proteolytic enzyme derived from pineapple stems. It contains several thiol endopeptidases and is extracted and purified via several methods. It is most commonly used as an anti-inflammatory agent, though scientists have also discovered its potential as an anticancer and antimicrobial agent. It has been reported as having positive effects on the respiratory, digestive, and circulatory systems, and potentially on the immune system. It is a natural remedy for easing arthritis symptoms, including joint pain and stiffness. This review details bromelain’s varied uses in healthcare, its low toxicity, and its relationship to nanoparticles. The door of infinite possibilities will be opened up if further extensive research is carried out on this pineapple-derived enzyme.

Mutations in genes encoding components of the mitochondrial DNA (mtDNA) replication machinery cause mtDNA depletion syndromes (MDSs), which associate ocular features with severe neurological syndromes. Here, we identified heterozygous missense mutations in single-strand binding protein 1 (SSBP1) in 5 unrelated families, leading to the R38Q and R107Q amino acid changes in the mitochondrial single-stranded DNA-binding protein, a crucial protein involved in mtDNA replication. All affected individuals presented optic atrophy, associated with foveopathy in half of the cases. To uncover the structural features underlying SSBP1 mutations, we determined a revised SSBP1 crystal structure. Structural analysis suggested that both mutations affect dimer interactions and presumably distort the DNA-binding region. Using patient fibroblasts, we validated that the R38Q variant destabilizes SSBP1 dimer/tetramer formation, affects mtDNA replication, and induces mtDNA depletion. Our study showing that mutations in SSBP1 cause a form of dominant optic atrophy frequently accompanied with foveopathy brings insights into mtDNA maintenance disorders.

Newly synthesized mitochondrial RNA is concentrated in structures juxtaposed to nucleoids, called RNA granules, that have been implicated in mitochondrial RNA processing and ribosome biogenesis. Here we show that two classical mtDNA replication factors, the mtDNA helicase Twinkle and single-stranded DNA-binding protein mtSSB, contribute to RNA metabolism in mitochondria and to RNA granule biology. Twinkle colocalizes with both mitochondrial RNA granules and nucleoids, and it can serve as bait to greatly enrich established RNA granule proteins, such as G-rich sequence factor 1, GRSF1. Likewise, mtSSB also is not restricted to the nucleoids, and repression of either mtSSB or Twinkle alters mtRNA metabolism. Short-term Twinkle depletion greatly diminishes RNA granules but does not inhibit RNA synthesis or processing. Either mtSSB or GRSF1 depletion results in RNA processing defects, accumulation of mtRNA breakdown products as well as increased levels of dsRNA and RNA:DNA hybrids. In particular, the processing and degradation defects become more pronounced with both proteins depleted. These findings suggest that Twinkle is essential for RNA organization in granules, and that mtSSB is involved in the recently proposed GRSF1-mtRNA degradosome pathway, a route suggested to be particularly aimed at degradation of G-quadruplex prone long non-coding mtRNAs.

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The mitochondrial genome (mtDNA) is assembled into nucleo-protein structures termed nucleoids and maintained differently compared to nuclear DNA, the involved molecular basis remaining poorly understood. In yeast (Saccharomyces cerevisiae), mtDNA is a ∼80 kbp linear molecule and Abf2p, a double HMG-box protein, packages and maintains it. The protein binds DNA in a non-sequence-specific manner, but displays a distinct ‘phased-binding’ at specific DNA sequences containing poly-adenine tracts (A-tracts). We present here two crystal structures of Abf2p in complex with mtDNA-derived fragments bearing A-tracts. Each HMG-box of Abf2p induces a 90° bend in the contacted DNA, causing an overall U-turn. Together with previous data, this suggests that U-turn formation is the universal mechanism underlying mtDNA compaction induced by HMG-box proteins. Combining this structural information with mutational, biophysical and computational analyses, we reveal a unique DNA binding mechanism for Abf2p where a characteristic N-terminal flag and helix are crucial for mtDNA maintenance. Additionally, we provide the molecular basis for A-tract mediated exclusion of Abf2p binding. Due to high prevalence of A-tracts in yeast mtDNA, this has critical relevance for nucleoid architecture. Therefore, an unprecedented A-tract mediated protein positioning mechanism regulates DNA packaging proteins in the mitochondria, and in combination with DNA-bending and U-turn formation, governs mtDNA compaction.

As Allium cepa is one of the most important condiment plants grown and consumed all over the world, various therapeutic and pharmacological effects of A. cepa were reviewed. Onion (Allium cepa) is a high dietary fiber-rich perennial herb that is placed under the family Amaryllidaceae. It contains high concentration of folic acid, vitamin B6, magnesium, calcium, potassium, and phosphorus as well as vitamins and minerals. It is widely used as an antimicrobial agent, but it showed anticancer, antidiabetic, antioxidant, antiplatelet, antihypertensive, and antidepressant effects and neuroprotective, anti-inflammatory, and antiparasitic effects and so on. It is said to have beneficial effects on the digestive, circulatory, and respiratory systems, as well as on the immune system. This review article was devoted to discussing many health benefits and traditional uses of onions in pharmacological perspectives, as well as the safety/toxicological profile. If more detailed research on this perennial herb is conducted, it will open the door to an infinite number of possibilities.