Self-immolation Assisted Morphology Transformation of Prebiotic Lipidated-cationic Amino Acids: Electro-droplet Mediated C-C Coupling Reaction to Synthesize Macromolecules.

Compartmentalization protected biomolecules from the fluctuating environments of early Earth. Although contemporary cells mostly use phospholipid-based bilayer membranes, the utility of non-bilayer compartments was not ruled out during the prebiotic and modern eras. In the present study, we demonstrated the prebiotic synthesis of lipidated cationic amino acid-based amphiphiles [lauryl ester of lysine (LysL); ornithine (OrnL); and 2,4-diamino butyric acid (DabL)] using model dry-down reaction. These amphiphiles self-assemble into micellar membranes. However, the OrnL and DabL-based micelles undergo pH-responsive transformation to lipid droplet-like morphologies, a modelcompartment in the prebiotic Earth. These cationic droplets encapsulated prebiotic molecules (isoprene) and assisted electron transfer reaction to synthesize isoprenoid derivatives at primitive Earth conditions. The self-assembly of prebiotic amphiphiles, their transformation to droplet compartments, and droplet-assisted C-C bond formation reaction might have helped the evolution to synthesize various biomolecules required for the origin of life.

ATP-Assisted Protocellular Membrane Formation with Ethanolamine-Based Amphiphiles.

Prebiotic membranes are one of the essential elements of the origin of life because they build compartments to keep genetic materials and metabolic machinery safe. Since modern cell membranes are made up of ethanolamine-based phospholipids, prebiotic membrane formation with ethanolamine-based amphiphiles and phosphates might act as a bridge between the prebiotic and contemporary eras. Here, we report the prebiotic synthesis of O-lauroyl ethanolamine (OLEA), O-lauroyl methyl ethanolamine (OLMEA), and O-lauroyl dimethylethanolamine (OLDMEA) under wet-dry cycles. Turbidimetric, NMR, DLS, fluorescence, microscopy, and glucose encapsulation studies highlighted that OLEA-ATP and OLMEA-ATP form protocellular membranes in a 3:1 ratio, where ATP acts as a template. OLDMEA with a dimethyl group did not form any membrane in the presence of ATP. ADP can also template OLEA to form vesicles in a 2:1 ratio, but the ADP-templated vesicles were smaller. This suggests the critical role of the phosphate backbone in controlling the curvature of supramolecular assembly. The mechanisms of hierarchical assembly and transient dissipative assembly are discussed based on templated-complex formation via electrostatic, hydrophobic, and H-bonding interactions. Our results suggest that N-methylethanolamine-based amphiphiles could be used to form prebiotic vesicles, but the superior H-bonding ability of the ethanolamine moiety likely provides an evolutionary advantage for stable protocell formation during the fluctuating environments of early earth.

Phosphate-Based Amphiphile and Lipidated Lysine Assemble into Superior Protocellular Membranes over Carboxylate and Sulfate-Based Systems: A Potential Missing Link between Prebiotic and the Modern Era?

Amphiphiles are among the most extensively studied building blocks that self-assemble into cell-like compartments. Most literature suggested that the building blocks/amphiphiles of early Earth (fatty acid-based membrane) were much simpler than today's phospholipids. To establish the bridge between the prebiotic fatty acid era and the modern phospholipid era, the investigation and characterization of alternate building blocks that form protocellular membranes are necessary. Herein, we report the potential prebiotic synthesis of alkyl phosphate, alkyl carboxylate, and alkyl sulfate amphiphiles (anionic) using dry-down reactions and demonstrate a more general role of cationic amino acid-based amphiphiles to recruit the anionic amphiphiles via ion-pair, hydrogen bonding, and hydrophobic interactions. The formation and self-assembly of the catanionic (mixed) amphiphilic system to vesicular morphology were characterized by turbidimetric, dynamic light scattering, transmission electron microscopy, fluorescence lifetime imaging microscopy, and glucose encapsulation experiments. Further experiments suggest that the phosphate-based vesicles were more stable than the alkyl sulfate and alkyl carboxylate-based systems. Moreover, the alkyl phosphate system can form vesicles at prebiotically relevant acidic pH (5.0), while alkyl carboxylate mainly forms cluster-type aggregates. An extended supramolecular polymer-type network formation via H-bonding and ion-pair interactions might order the membrane interface and stabilize the phosphate-based vesicles. The results suggest that phosphate-based amphiphiles might be a superior successor to fatty acids as early compartment building blocks. The work highlights the importance of previously unexplored building blocks that participate in protocellular membrane formation to encapsulate important precursors required for the functions of early life.

Molecular-level insights into a tripolyphosphate and pyrophosphate templated membrane assembly.

Templated assembly of small molecules into nano-structural architectures has been used extensively by nature throughout its evolution. These systems have also been studied in artificial systems to design a phosphate templated assembly. However, it is yet to be investigated how the molecules interact among themselves at the molecular level and whether the phosphate templated assembly has any role in the formation of prebiotic protocellular membranes. Here, we report the prebiotic synthesis of choline-based cationic amphiphiles (-N+Me3) and the templated assembly of these amphiphiles with tripolyphosphate (TPP) and pyrophosphate (PPi). SEM, TEM, FLIM, DLS, fluorescence, and encapsulation studies suggest that the number of phosphate units in the phosphate backbone controls the formation and size of the protocell vesicles. Isothermal titration calorimetry, turbidimetric studies, and NMR experiments suggest that the cationic amphiphile forms a 3 : 1 catanionic complex with TPP and a 2 : 1 catanionic complex with PPi. The templated catanionic complex further self-assembles into vesicles, and the structure of the complex guides the size of the assembly. The size-controlling ability of the phosphate backbone might have been utilized in the prebiotic era to support the dynamics and tunability of protocellular membrane compartments.

Self-assembled prebiotic amphiphile-mixture exhibits tunable catalytic properties.

Protocellular surface formation via the self-assembly of amphiphiles, and catalysis by simple peptides/proto-RNA are two important pillars in the evolution of protocells. To hunt for prebiotic self-assembly-supported catalytic reactions, we thought that amino-acid-based amphiphiles might play an important role. In this paper, we investigate the formation of histidine-based and serine-based amphiphiles under mild prebiotic conditions from amino acid : fatty alcohol and amino acid : fatty acid mixtures. The histidine-based amphiphiles were able to catalyze hydrolytic reactions at the self-assembled surface (with a rate increase of ∼1000-fold), and the catalytic ability can be tuned by linkage of the fatty carbon part to histidine (N-acylated vs. O-acylated). Moreover, the presence of cationic serine-based amphiphiles on the surface enhances the catalytic efficiency by another ∼2-fold, whereas the presence of anionic aspartic acid-based amphiphiles reduces the catalytic activity. Ester partitioning into the surface, reactivity, and the accumulation of liberated fatty acid explain the substrate selectivity of the catalytic surface, where the hexyl esters were found to be more hydrolytic than other fatty acyl esters. Di-methylation of the -NH2 of OLH increases the catalytic efficacy by a further ∼2-fold, whereas trimethylation reduces the catalytic ability. The self-assembly, charge-charge repulsion, and the H-bonding to the ester carbonyl are likely to be responsible for the superior (∼2500-fold higher rate than the pre-micellar OLH) catalytic efficiency of O-lauryl dimethyl histidine (OLDMH). Thus, prebiotic amino-acid-based surfaces served as an efficient catalyst that exhibits regulation of catalytic function, substrate selectivity, and further adaptability to perform bio-catalysis.

Lipidated Lysine and Fatty Acids Assemble into Protocellular Membranes to Assist Regioselective Peptide Formation: Correlation to the Natural Selection of Lysine over Nonproteinogenic Lower Analogues.

The self-assembly of prebiotically plausible amphiphiles (fatty acids) to form a bilayer membrane for compartmentalization is an important factor during protocellular evolution. Such fatty acid-based membranes assemble at relatively high concentrations, and they lack robust stability. We have demonstrated that a mixture of lipidated lysine (cationic) and prebiotic fatty acids (decanoic acid, anionic) can form protocellular membranes (amino acid-based membranes) at low concentrations via electrostatic, hydrogen bonding, and hydrophobic interactions. The formation of vesicular membranes was characterized by dynamic light scattering (DLS), pyrene and Nile Red partitioning, cryo-transmission electron microscopy (TEM) images, and glucose encapsulation studies. The lipidated nonproteinogenic analogues of lysine (Lys), such as ornithine (Orn) and 2,4-diaminobutyric acid (Dab), also form membranes with decanoate (DA). Time-dependent turbidimetric and 1H NMR studies suggested that the Lys-based membrane is more stable than the membranes prepared from nonproteinogenic lower analogues. The Lys-based membrane embeds a model acylating agent (aminoacyl-tRNA mimic) and facilitates the colocalization of substrates to support regioselective peptide formation via the α-amine of Lys. These membranes thereby assist peptide formation and control the positioning of the reactants (model acylating agent and -NH2 of amino acids) to initiate biologically relevant reactions during early evolution.

An inquest into regulatory mechanism of caveolin by ischemic preconditioning against orchidectomy-challenged rat heart.

Lower level of testosterone in men is related to major risks of cardiovascular diseases. This risk may increase due to the opening of mitochondrial permeability transition pore (mPTP). The mPTP is also regulated by ischemic preconditioning (IPC) and a membrane protein known as caveolin. The cardioprotective effect of IPC is the most effective methodologies used in testosterone deficiency. Daidzein (DDZ) a caveolin inhibitor shows cardioprotective action. The experiment has been designed to evaluate the pretreated DDZ effect in IPC-mediated cardioprotective action in orchidectomy (OCZ)-challenged rat heart. The experiment was designed on male Wistar rats with/without OCZ. The level of testosterone is decreased by OCZ which reduces general body growth. Isolated heart from normal and OCZ rat was tied up on Langendorff's perfused apparatus and followed by ischemic reperfusion (IR) and IPC cycle. To investigate the cardioprotective effect of DDZ in heart with testosterone deficiency, a total of nine groups, each consisting of six rats (n = 6) were as follows: Sham, IR, IPC, IPC + OCZ, IPC + DDZ, IPC + OCZ + DDZ, IPC + sodium nitrite, IPC + OCZ + sodium nitrite, IPC + OCZ + DDZ + sodium nitrite. Hemodynamic parameters, cellular injury (infarct size, LDH, CKMB and cardiac troponin-T), oxidative stress, mitochondrial function, integrity and immunoblot analysis were assessed for each group. The experimental data showed that DDZ potentiated IPC-mediated increase in the heart rate, left ventricular diastolic pressure, coronary flow; + dp/dtmax, and - dp/dtmax. The pretreated DDZ decreases the action of LDH and CKMB, myocyte size, cardiac collagen content, infarct size and ventricular fibrillation and attenuation in oxidative stress and mitochondrial dysfunction in OCZ-challenged rat heart in all sets of experiments. Sodium nitrite, a producer of nitric oxide (NO), enhanced potentiating effects of DDZ on IPC-mediated cardioprotection in OCZ-challenged rats. These observations show that the downregulation of caveolin through impaired opening of mPTP during reperfusion and caveolin might be a potential adjuvant to IPC against cardiac injury in OCZ-challenged rats.

The microenvironment and pKa perturbation of aminoacyl-tRNA guided the selection of cationic amino acids.

The proteinogenic lysine (Lys) and arginine (Arg) have multiple methylene groups between α-carbon and the terminal charged centre. Why nature did not select ornithine (Orn), 2,4-diamino butyric acid (Dab) and 2,3-diamino propionic acid (Dpr) with fewer methylene groups in the side chain remains an important question! The propensity of aminoacyl-tRNA (aa-tRNA) model substrates towards self-degradation via intramolecular lactamization was studied using UV spectroscopy and 1H-NMR titration, which showed that Lys and Arg remain stable, and Orn and Dab cyclize to lactam. Hydrophobicity-assisted surface mediated model peptide formation highlighted that the microenvironment and pKa perturbation led to poor regioselectivity (α-amine vs. terminal amine) in Dpr and other non-proteinogenic analogues. The α-selectivity became even poorer in the presence of phosphate, making them ill-suited for peptide synthesis. Superior regioselectivity of the Lys aa-tRNA model substrate suggests that the extra methylene bridge helped nature to separate the microenvironments of the α-amine and ε-amine to synthesize the peptide backbone.

Cuticle bearing fossil leaves from Mio-Pliocene period in the Sub Himalayan zone and its phytogeographical and environmental implications.

A variety of fossil leaves were collected from the Siwalik group of India and Nepal. Few of them possessing sufficient cuticle were identified on the basis of morphological and cuticular features (epidermal cells, stomatal density, stomatal index etc). They closely resembled with the extant taxa, Pterospermum acerifolium (Sterculiaceae), Dichapetolum gelonioides (Dichapetalaceae), Paranephelium mocrophyllum, P. xestophyllum (Sapindaceae), Gluto renghos (Anacardiaceae) and Mimusops elengi (Sapotaceae). The habit, habitat and present day distribution of the above modern comparable taxa suggest the prevalence of tropical humid environment during deposition of Siwalik sediments in the Sub-Himalayan zone. The extinction of the above comparable taxa (except Pterospermum acerifolium) from the Sub-Himalayan zone indicates the environmental change after Mio- Pliocene time. The epidermal and stomatal features of the fossil leaves collectively suggest the existence of a broad leaved mesophytic forest at low altitude having comparatively high humidity all along the Himalayan foot hills during 8-12 million years ago.

Modulation of Inula racemosa Hook Extract on Cardioprotection by Ischemic Preconditioning in Hyperlipidaemic Rats.

Objectives: Hyperlipidemia (HL) is a major cause of ischemic heart diseases. The size-limiting effect of ischemic preconditioning (IPC), a cardioprotective phenomenon, is reduced in HL, possibly because of the opening of the mitochondrial permeability transition pore (MPTP). The objective of this study is to see what effect pretreatment with Inula racemosa Hook root extract (IrA) had on IPC-mediated cardioprotection on HL Wistar rat hearts. An isolated rat heart was mounted on the Langendorff heart array, and then ischemia reperfusion (I/R) and IPC cycles were performed. Atractyloside (Atr) is an MPTP opener. Methods: The animals were divided into ten groups, each consisting of six rats (n = 6), to investigate the modulation of I. racemosa Hook extract on cardioprotection by IPC in HL hearts Sham control, I/R Control, IPC control, I/R + HL, I/R + IrA + HL, IPC + HL, IPC + NS + HL, IPC + IrA+ HL, IPC + Atr + oxidative stress, mitochondrial function, integrity, and hemodynamic parameters are evaluated for each group. Results: The present experimental data show that pretreatment with IrA reduced the LDH, CK-MB, size of myocardial infarction, content of cardiac collagen, and ventricular fibrillation in all groups of HL rat hearts. This pretreatment also reduced the oxidative stress and mitochondrial dysfunction. Inhibition of MPTP opening by Atr diminished the effect of IrA on IPC-mediated cardioprotection in HL rats. Conclusion: The study findings indicate that pretreatment with IrA e restores IPC-mediated cardioprotection in HL rats by inhibiting the MPTP opening.

Co-Adjuvancy of Solasodine & CoQ10 Against High Fat Diet-Induced Insulin Resistance Rats Via Modulating IRS-I and PPAR-γ Proteins Expression.

Insulin resistance (IR) is a condition in which target cells become insensitive to normal insulin concentrations in order to deliver glucose. The goal of this study was to see if solasodine combined with coenzyme Q10 could help rats with insulin resistance caused by a high-fat diet (HFD) by regulating the expression of IRS-I and PPAR-γ proteins.One of the six groups (n=6) got a conventional diet for 16 weeks as a control (normal), the HFD was given to the other five groups for 16 weeks, which further classified as-one group as HFD control while others treated with pioglitazone (10 mg/kg), coenzyme Q10 (50 mg/kg), solasodine (50 mg/kg) and combination of solasodine and coenzyme Q10i.e. SDQ10 (total 50 mg/kg) for the last 4 weeks orally once daily. Blood and tissue samples were collected by the end of study period for the biochemical and histological studies. As a result, HFD fed rats exhibited a significant increase in food and energy intake, body mass index, kidney and pancreas weight, fasting glucose, glycosylated haemoglobin, insulin level, liver enzyme ALT and AST and decrease antioxidant activity of superoxide dismutase and catalase. HFD received animals also produced a lower level of p-IRS1 and PPAR-y protein expression in western blot analysis. SDQ10 in combination successfully restored the above-mentioned complexity of insulin resistance caused by aHFD. Besides, increasesthe antioxidant activity of superoxide dismutase and catalase and normalized the architecture of kidney, pancreas and adipose tissue as well astreatment with SDQ10 raised the level of p-IRS1 and PPAR-y protein in liver tissue. As a result, supplementing with solasodine and coenzyme Q10 reversed the effect of the HFD on p-IRS1 and PPAR-y protein in liver tissue while also alleviating insulin resistance symptoms.

Erratum to "Perceptions and practices of COVID-19 protective measures among the general public of North India" [Clin Epidemiol Glob Health 13 (2022) 100927].

[This corrects the article DOI: 10.1016/j.cegh.2021.100927.].

Perceptions and practices of COVID-19 protective measures among the general public of North India.

BACKGROUND: India has a high COVID-19 burden. The Indian government responded to the pandemic by mandating its population to adhere to certain Protective Measures (PMs). Compliance to these PMs depends on their acceptability and adaptability among the general public. AIMS: To explore the perceptions and practices of COVID-19 related PMs among the general public of North India. METHODS: Qualitative study in four administrative districts (Lucknow, Etawah, Patna and Darbhanga) of North India. Two urban and two rural districts were purposefully selected. Audio in-depth interviews (IDIs) were conducted with healthy caregivers of children (2-59 months). Data was managed using Atlast Ti and analyzed using conventional content analysis. RESULTS: From July-Sep 2020, 60 IDIs were conducted; 36.6% (22/60) were females and 26.6% (16/60) had below primary education. Respondents concurred that most people in their society flouted the recommended PMs. The reasons for poor/non-compliance with PMs were: perceived poor susceptibility to illness, perceived less severity of COVID-19 and low perceived benefits of complying with the PMs. Respondents opined that COVID-19 is less prevalent in rural areas and among the educated population. Most respondents were aware of the recommended PMs and opined that these must be followed, however subjective norms, social norms and behavioral intentions negatively impacted compliance. CONCLUSIONS: Since there was poor community perception of susceptibility to COVID-19 as well as poor perceived severity, the community did not understand the benefits of adhering to the recommended PMs. Therefore, future health communication strategies must take these into account to increase the possibility of success.

Soft Malleable Vesicles: versatile carriers for efficient topical delivery of fungal therapeutics.

Fungal infections have become a subject of great concern and the incidence of fungal infections is increasing, presenting an enormous challenge to healthcare professionals. Since most of the fungal infections are occurring over the skin, the treatment option of these infections always involves topical application. However, in topical delivery drug reaches into systemic circulation through different barriers of skin. Nevertheless, due to the low permeability, skin restricts the movement of many drugs. Hence, a delivery system is required, which deliver the medicament into the skin layers or through the skin and into the systemic circulation. Ethosomes or Soft malleable vesicles are the novel lipid vesicular carrier that offer improved skin permeability and efficient delivery due to their structure and composition. They contain high concentration of ethanol, which increases the fluidity of the skin. Therefore, in the present paper, we have explored the utility of ethosomal systems in the topical treatment of fungal infections. Structure, compositions types, mechanism and techniques of preparation of ethosome also discussed in the paper.

Influence of Temperature on Void Collapse in Single Crystal Nickel under Hydrostatic Compression.

Employing atomistic simulations, we investigated the void collapse mechanisms in single crystal Ni during hydrostatic compression and explored how the atomistic mechanisms of void collapse are influenced by temperature. Our results suggest that the emission and associated mutual interactions of dislocation loops around the void is the primary mechanism of void collapse, irrespective of the temperature. The rate of void collapse is almost insensitive to the temperature, and the process is not thermally activated until a high temperature (∼1200-1500 K) is reached. Our simulations reveal that, at elevated temperatures, dislocation motion is assisted by vacancy diffusion and consequently the void is observed to collapse continuously without showing appreciable strain hardening around it. In contrast, at low and ambient temperatures (1 and 300 K), void collapse is delayed after an initial stage of closure due to significant strain hardening around the void. Furthermore, we observe that the dislocation network produced during void collapse remains the sample even after complete void collapse, as was observed in a recent experiment of nickel-base superalloy after hot isostatic pressing.

Caveolins; An Assailant or An Ally of Various Cellular Disorders.

Caveolae have impressive morphological highlights of the cytomembrane of mammalian cells which involve in wide diversity of cellular functions involving signaling pathways and cholesterol hastening. Caveolin proteins possess a 'scaffolding' domain which for caveolin-1 and caveolin-3 appear to act a dominant role in signal regulation through caveolae. Caveolin-1 is treated to be protein in the cytomembrane entrapped with caveolae in endothelial cells and vascular smooth muscle cells which diminish nitric oxide (NO) by fill up the calcium/calmodulin (Ca2+/CaM) confining point of endothelial nitric oxide synthase (eNOS), decrease NO generation produce endothelial dysfunction and atherosclerotic injury development. It is a cholesterol-binding layer protein associated with cell cholesterol transport and also shows cardioprotective action through ischemic preconditioning (IPC) in diabetic and postmenopausal rat heart. Additionally it is ensnared in the procedures of tumorigenesis, prostate disease, and inflammation. The present study in the paper is to explore the structural functionalities of caveolins and their contributory role in CVS disorders and various other diseases.

A headgroup linker perturbs pKavia acyl chain migration: designing base-labile supramolecular assemblies.

Acyl chain transfer, which perturbs the protonation equilibrium of amine and reduces the apparent pKa by 2.0-2.5 units, is used to develop a liposome-based drug delivery system.

Caprine leptospirosis: Hematobiochemical and urinalyses studies.

AIM: The present study was designed to evaluate clinicopathological alterations in naturally occurring leptospirosis in goats of South Gujarat region, Gujarat. MATERIALS AND METHODS: A total 459 blood/serum and 292 urine samples were collected from different districts of South Gujarat region, India. Blood/serum and urine samples were subjected to hematobiochemical analyses and urinalyses. The serum samples were screened for anti-leptospiral antibodies using the microscopic agglutination test (MAT). On the bases of presence or absence of anti-leptospiral antibodies in serum, seropositive and seronegative groups were made. The results were analyzed using standard statistical methods to know pathological changes in the disease. RESULTS: In MAT, out of 459, 116 goats were seropositive, and 343 were seronegative. In hematobiochemical analyses, statistically significant (p<0.01) decrease in values of packed cell volume, hemoglobin (Hb) concentration, mean corpuscular Hb concentration and total protein and increased activity/level of alanine aminotransferase, aspartate aminotransferase and total bilirubin between seropositive and seronegative goats were noted. Urinalyses did not reveal any specific changes. In the dark field microscopy, urine samples were found to be negative for leptospires. CONCLUSION: Hematobiochemical changes noted in seropositive goats were indicative of hepatic damage, and this knowledge would aid in the therapeutic management of the disease.