The beginning of life on Earth and its evolution over billions of years continue to intrigue researchers worldwide. The central dogma or the directional flow of genetic information from a deoxyribose nucleic acid (DNA) template to a ribose nucleic acid (RNA) transcript, and finally into a functional protein, is fundamental to cellular structure and functions. DNA functions as the blueprint of the cell and carries genetic information required for the synthesis of functional proteins. Conversely, proteins are required for the synthesis of DNA. Therefore, whether DNA emerged first or protein, continues to remain a matter of debate.
This molecular version of the “chicken and egg” question led to the proposition of an “RNA World.” RNAs in the form of ‘ribozymes’ or RNA enzymes carry genetic information similar to DNA and also possess catalytic functions like proteins. The discovery of ribozymes further fueled the RNA World hypothesis where RNA served dual functions of “genetic information storage” and “catalysis,” facilitating primitive life activities solely by RNA. While modern ribosomes are a complex of RNAs and proteins, ribozymes during early evolutionary stages may have been pieced together through the assembly of individual functional RNA units.
To test this hypothesis, Professor Koji Tamura, along with his team of researchers at the Department of Biological Science and Technology, Tokyo University of Science, conducted a series of experiments to decode the assembly of functional ribozymes. For this, they designed an artificial ribozyme, R3C ligase, to investigate how individual RNA units come together to form a functional structure. Giving further insight into their work published on 17 April 2024, in Life, Prof. Tamura states, “The R3C ligase is a ribozyme that catalyzes the formation of a 3’,5’-phosphodiester linkage between two RNA molecules. We modified the structure by adding specific domains that can interact with various effectors.”
Within ribosomes, which are the site of protein synthesis, RNA units assemble to function as Peptidyl Transferase Center (PTC) in a way such that they form a scaffold for the recruitment of amino acids (individual components of a peptide/protein) attached to tRNAs (featured in Nature magazine (https://www.nature.com/articles/d41586-023-00574-4)). This is an important insight into the evolutionary history of protein synthesis systems, but it is not sufficient to trace the evolutionary pathway based on the RNA World hypothesis.
To explore if the elongation of RNA, achieved by linking individual RNA units together, is regulated allosterically, the researchers altered the structure of the R3C ligase. They did this by incorporating short RNA sequences that bind adenosine triphosphate (ATP), a vital energy carrier molecule in cells, into the ribozyme. The team noted that R3C ligase activity was dependent on the concentration of ATP, with higher activity observed at higher concentrations of ATP. Further, an increase in the melting temperature (Tm value) indicated that the binding of ATP to R3C ligase stabilized the structure, which likely influenced its ligase activity.
Similarly, on fusing an L-histidine-binding RNA sequence to the ribozyme, they noted an increase in ligase activity at increasing concentrations of histidine (a key amino acid). Notably, the increase in activity was specific to increasing concentrations of ATP or histidine; no changes were observed in response to other nucleotide triphosphates or amino acids. These findings suggest that ATP and histidine act as effector molecules that trigger structural conformational changes in the ribozyme, which further influence enzyme stability and activity.
ATP is the central energy carrier of the cell which supports numerous molecular processes, while, histidine is the most common amino acid found in the active site of enzymes, and maintains their acid-base chemistry. Given, the important roles of ATP and histidine in RNA interactions and molecular functions, these results provide novel insights into the role of RNA in early evolution, including the origin of the genetic code. Furthermore, engineered ribozymes such as the one developed in this study hold significant promise in a myriad of applications including targeted drug delivery, therapeutics, nano-biosensors, enzyme engineering, and synthesis of novel enzymes with uses in various industrial processes.
Overall, this study can offer insights into how the transition from the RNA World to the modern “DNA/Protein World” occurred. A fundamental understanding of the RNA World in turn, can enhance their use in real-life applications.
“This study will lead to the elucidation of the process of ‘allostericity-based acquisition of function and cooperativity’ in RNA evolution. The RNA-RNA interactions, RNA-amino acid interactions, and allostericity applied in this research can guide the fabrication of arbitrary RNA nanostructures, with various applications,” concludes Prof. Tamura.
‘No mean feat’ – Stage-win aim for Laurence Pithie at Giro d’Italia debut – Cyclingnews
Laurence Pithie may be only taking on his very first Grand Tour when he lines up in Turin on Saturday to debut at the Giro d’Italia, however such has been the meteoric rise of the Groupama-FDJ rider that he will be doing it with big aims and the support of his team.
The 21-year-old New Zealander, who can hold on through the hills and deliver a fast finish, has already capitalised on his strengths to capture one WorldTour win this season, the Cadel Evans Great Ocean Road Race, and after regularly clinging on to key moves in the Classics he is now looking to taste victory again in Italy.
“Being at the start in Turin for three weeks of competition is a real opportunity, and discovering your first Grand Tour as leader is no mean feat,” said Pithie in a statement from his French team. “I’m arriving on the Italian roads with a lot of expectations, so we’ll take one opportunity after another and give everything we’ve got, every day, to go for this stage win that unites us all.”
The second year WorldTour professional may be untested at a Grand Tour, but the rider who has shown an ability to quickly analyse, learn and adapt has garnered the unequivocal support of his team.
“With a strong, complementary team, we’ll be supporting Laurence Pithie in his aim to win stages, whether flat or hilly,” said Directeur Sportif Frédéric Guesdon in a team statement. “Everyone will play an essential role around our sprinter to maximise our chances of winning, and I expect them to be dedicated to their leader. They’re all very motivated to be at the start in Turin on Saturday.”
The European spring emphasised the prowess on display in Australia in January, with Pithie twice on the podium on stages of Paris-Nice before regularly being in elite company through the toughest Classics. He may not have netted a big Classics result – with seventh at Paris-Roubaix the highest finish – but showed ample evidence of the potential to take victory on the biggest stages in the future. His Groupama-FDJ team are rallying to do what they can to make it sooner, rather than later.
“We know that Laurence is a strong guys who knows how to manage on his own in the final stages, but the adversity will be high and it will be in his interest to rely on us,” said team captain Olivier le Gac.
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The young leader will be surrounded by a young team, with four other Giro first timers and half the squad eligible for the youth category. As well as Le Gac, Pithie will be racing alongside Lewis Askey, Cyril Bathe, Clement Davy, Lorenzo Germani, Fabien Lienhard and Enzo Paleni.
“With the support of this great team, I know that anything is possible,” said Pithie.
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Apple Working To Fix Issue Causing iPhone Alarms To Not Sound – NDTV
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Apple is working on a swift fix to get everyone back on track
A software issue left some iPhone users snoozing through silent alarms, prompting a flurry of frustrated posts on social media. Many rely on their phones as their primary alarm clock, and the unexpected lie-in caused some chaos for early risers. Thankfully, Apple is working on a swift fix to get everyone back on track, BBC reported,
A social media user complained that she had set “like five alarms” and they didn’t go off.
While confirming the issue of silent iPhone alarms, Apple hasn’t pinpointed the cause or offered a workaround to prevent missed wake-up calls. Additionally, the number of affected users and specific iPhone models remain unknown.
The news initially surfaced on NBC’s Today Show, highlighting the plight of early risers. In the absence of an official fix, users can attempt a few solutions:
Double-Check Settings: Ensure alarms are set correctly and the volume is adequate.
Attention Feature Suspect: Some speculate that Apple’s “attention-aware features” might be silencing alarms.
These features, available on iPhone X and later models, automatically adjust alert volume based on user attention. TikTok users suggest these features could mute alarms if users sleep facing the screen.
Apple aims for a swift resolution, but until then, users might need to resort to old-fashioned alarm clocks to ensure timely awakenings.
Broken iPhone alarms are nothing new for iOS, in 2015 Apple released an update to fix its alarms, among other things — and they happen on other devices, too.
BULAWAYO City Council (BCC) has revealed that cholera cases are on the decline after no new cases were recorded in the past three weeks.
BULAWAYO City Council (BCC) has revealed that cholera cases are on the decline after no new cases were recorded in the past three weeks.
All of Zimbabwe’s 63 districts have reported cholera cases, as April 30 this year, 46 cases were hospitalised at Mwenezi (1), Zaka (2), Bikita (1) in Masvingo province, Mutare (14) Chimanimani (1) in Manicaland province and Bindura (3), Mt Darwin (4) in Mashonaland Central.
One case was recorded in Harare province, Sanyati (13), Chegutu (3) in Mashonaland West province while one has also been recorded at Wedza District Hospital in Mashonaland East province and two cases in Kwekwe, Midlands province.
BCC health services director Edwin Sibanda told NewsDay in an interview that there are 13 cumulative cases with 13 cumulative recoveries and zero deaths.
“We have had no cases for more than three weeks. There are zero new confirmed cases, 13 cumulative confirmed cases, 0 new cholera deaths and 13 cumulative recoveries. We have also recorded zero active confirmed cases, zero new suspected cholera cases and 46 cumulative suspected cholera cases,’’ Sibanda said.
He said there were no new Rapid Diagnosis Test, 31 positive cumulative Rapid Diagnosis Test cases with zero pending microscopy culture sensitive results and one cumulative suspected cholera death.
“We advise residents to continue to wash their hands and eat food while it is still hot,’’ he said.
Zimbabwe has been grappling with a cholera outbreak since February 2023, with the number of cases increasing across the country.
Alarming proportions were reached in August 27, 2023, resulting in 3 894 cholera cases and 96 fatalities.
Notably, this pandemic extended its reach to all 10 provinces across the country, with Harare (1 616), Mutare (1 534) and Bulawayo (324) reporting the highest cumulative cases accounting for 89% of the total cases.