Structural Studies Research Articles

Structural study of mixed metal oxide catalysts comprising Mg, Ca, and Al used for upgrading biodiesel byproduct glycerol to glycerol carbonate

Glycerol is a by-product in biodiesel production. It is possible to convert glycerol to glycerol carbonate by carbonylation with CO2. In this work, novel mixed metal oxides of Mg-Ca, Mg-Al, and Ca-Al were prepared by co-precipitation method, and used as catalysts for this reaction for the first time. Catalysts were characterized through XRD, BET surface area analyzer, XPS, ICP-OES, SEM, and CO2-TPD analyses. Mg0.75Ca0.25O catalyst showed the highest glycerol conversion of 18.2±0.7%, and glycerol carbonate yield of 12% at initial conditions. Reaction parameters including pressure, temperature, and catalyst loading were optimized, when Mg0.75Ca0.25O catalyst was used, to achieve the highest glycerol carbonate yield. The optimal reaction parameters were pressure of 7 MPa, temperature of 180 ⁰C, and catalyst loading of 8.5%. Glycerol conversion was 25.7% and the glycerol carbonate yield was 16% at optimized condition. Morphology and chemical structure of Mg-Ca catalyst were also investigated.

Efficient Extraction of Wool Keratin Governed by Simultaneous Cation and Anion Effects: From Secondary Structure Studies to High α-Helix Keratin Content

Efficient Extraction of Wool Keratin Governed by Simultaneous Cation and Anion Effects: From Secondary Structure Studies to High α-Helix Keratin Content

Study of the biocompatibility of porous 3D-TiNi implants in vivo

Introduction. Porous TiNi alloys are widely used in medicine as osteoreplacement implants due to their unique properties of superelasticity and biocompatibility, but their clinical use is severely limited by time-consuming manual fabrication and the inability to create precise geometries. Reconstructive surgery for the replacement of bone defects requires biocompatible endoprostheses of individual shape and complex geometry. The use of porous 3D-TiNi implants can be a solution to many problems in traumatology and bone oncology.Aim: To evaluate the possibility of using porous 3D-TiNi implants in osteoplastic surgery based on a study of the structure and biocompatibility of the material under in vivo conditions.Material and Methods. Porous samples in the form of cones and a single implant for maxillofacial surgery were prepared from TiNi powder by selective laser melting. To print an individual implant for maxillofacial surgery, the personal data of the patient at the Oncology Research Institute were used. The macrostructure, elemental and phase composition of porous titanium nickelide samples were investigated using scanning microscopy and X-ray diffraction analysis. The biocompatibility of porous cone-shaped samples was evaluated in vivo using guinea pigs whose condition was analysed by CT scanning.Results. Structural studies of porous titanium nickelide samples showed that selective laser melting can be used to obtain a continuous porous structure with strong contact bridges between particles of a three-phase powder. In vivo testing of the cone-shaped implants showed no local inflammatory changes, rejection or deformation of the hind limb axes of the experimental animals. The basic feasibility of fabricating a custom implant of complex geometry from TiNi powder using selective laser melting according to a patient’s MSCT data was demonstrated.Conclusions. Porous 3D-TiNi implants obtained by selective laser melting showed high biocompatibility under in vivo conditions. An experimental study confirmed the efficacy and ease of use of 3D TiNi implants, their excellent self-fixation in bone tissue, and bone tissue augmentation at the interface with the implant. The macrostructure, chemical and phase composition of the implant material was found to be close to traditional porous TiNi alloys. It was shown that the method of selective laser melting makes it possible to create complex geometric defects in bone tissue from TiNi.

New Insights into Hsp90 Structural Plasticity Revealed by cryoEM

Heat Shock Protein 90 (Hsp90) acts as a crucial molecular chaperone, playing an essential role in activating numerous signaling proteins. The intricate mechanism of Hsp90 involving ATPase-coupled conformational changes and interactions with cochaperone proteins has been elucidated through biochemical and structural analyses, revealing its activation mechanism and its diverse set of “client” proteins. Despite recent advancements, certain aspects of Hsp90’s ATPase-coupled mechanism remain contentious, and the specific nature of the alterations induced by Hsp90 in client proteins remains largely undiscovered. In this review, we explore the current understanding of Hsp90’s structure and function, drawing insights from single-particle cryoEM studies. Structural studies on Hsp90 using cryoEM have provided valuable insights into the structural dynamics and interactions of this molecular chaperone. CryoEM structures have been instrumental in understanding the ATPase-coupled conformational changes that Hsp90 undergoes during its chaperone cycle. We also highlight recent progress in elucidating the structure of the ATP-bound state of the complete dimeric chaperone. Furthermore, we delve into the roles played by the multitude of cochaperones that collaborate with Hsp90, providing a glimpse into their biochemical mechanisms through the newly obtained cryoEM structures of Hsp90 cochaperone complexes.

Ethidium bromide adsorption on pyrophyllite nanoclay: Insights from batch, thermodynamic, kinetic, and recyclability studies and optimization through response surface methodology

The efficient removal of Ethidium Bromide (EB), a toxic yet widely used chemical in biochemical industries and laboratories, is crucial to avoid its detrimental effect on human health, aquatic life, and the environment. One effective method is adsorption onto inert surfaces, but the choice of adsorbents is critical for the success of the removal protocols, primarily because of the limitations such as low adsorption capacity, high cost, limited availability, and a lack of understanding of the adsorption mechanism. In this work, Pyrophyllite Nanoclay (PNC), a naturally abundant aluminosilicate is explored as a promising adsorbent for EB. The adsorption process follows the Freundlich isotherm and displays pseudo-second-order kinetics. Under the optimized condition, PNC demonstrates nearly quantitative adsorption of EB and the maximum adsorption efficiency obtained from experiment was 6.53 mg/g (0.017 mmol/g) at room temperature under optimized condition. Through thermodynamic, kinetic analysis coupled with characterization techniques, the mechanism of adsorption is proposed. The adsorbent proves to be reusable, maintaining its performance over three cycles. The utility of the process is further validated and optimized using Response Surface Methodology (RSM). The present work focuses on the performance of PNC as adsorbent and elucidates distinctive surface adsorption mechanism (in comparison to other nanoclays), thus emphasizing the significance of structural, experimental, mechanistic and validation studies in choosing the right adsorbent for the removal toxic chemicals.

Exploring the coordination chemistry of ruthenium complexes with lysozymes: structural and in-solution studies.

This study presents a comprehensive structural analysis of the adducts formed upon the reaction of two Ru(III) complexes [HIsq][trans-RuIIICl4(dmso)(Isq)] (1) and [H2Ind][trans-RuIIICl4(dmso)(HInd)] (2) (where HInd-indazole, Isq-isoquinoline, analogs of NAMI-A) and two Ru(II) complexes, cis-[RuCl2(dmso)4] (c) and trans-[RuCl2(dmso)4] (t), with hen-egg white lysozyme (HEWL). Additionally, the crystal structure of an adduct of human lysozyme (HL) with ruthenium complex, [H2Ind][trans-RuCl4(dmso)(HInd)] was solved. X-ray crystallographic data analysis revealed that all studied Ru complexes, regardless of coordination surroundings and metal center charge, coordinate to the same amino acids (His15, Arg14, and Asp101) of HEWL, losing most of their original ligands. In the case of the 2-HL adduct, two distinct metalation sites: (i) Arg107, Arg113 and (ii) Gln127, Gln129, were identified. Crystallographic data were supported by studies of the interaction of 1 and 2 with HEWL in an aqueous solution. Hydrolytic stability studies revealed that both complexes 1 and 2 liberate the N-heterocyclic ligand under crystallization-like conditions (pH 4.5) as well as under physiological pH conditions, and this process is not significantly affected by the presence of HEWL. A comparative examination of nine crystal structures of Ru complexes with lysozyme, obtained through soaking and co-crystallization experiments, together with in-solution studies of the interaction between 1 and 2 with HEWL, indicates that the hydrolytic release of the N-heterocyclic ligand is one of the critical factors in the interaction between Ru complexes and lysozyme. This understanding is crucial in shedding light on the tendency of Ru complexes to target diverse metalation sites during the formation and in the final forms of the adducts with proteins.

Structural characterization of methylation-independent PP2A assembly guides alphafold2Multimer prediction of family-wide PP2A complexes

Dysregulation of phosphorylation-dependent signaling is a hallmark of tumorigenesis. Protein phosphatase 2 (PP2A) is an essential regulator of cell growth. One scaffold subunit (A) binds to a catalytic subunit (C) to form a core AC heterodimer, which together with one of many regulatory (B) subunits forms the active trimeric enzyme. The combinatorial number of distinct PP2A complexes is large, which results in diverse substrate specificity and subcellular localization. The detailed mechanism of PP2A assembly and regulation remains elusive and reports about an important role of methylation of the carboxy terminus of PP2A C are conflicting. A better understanding of the molecular underpinnings of PP2A assembly and regulation is critical to dissect PP2A function in physiology and disease. Here, we combined biochemical reconstitution, mass spectrometry, X-ray crystallography and functional assays to characterize the assembly of trimeric PP2A. In vitro studies demonstrated that methylation of the carboxy-terminus of PP2A C was dispensable for PP2A assembly in vitro. To corroborate these findings, we determined the X-ray crystal structure of the unmethylated PP2A Aα-B56ε-Cα trimer complex to 3.1 Å resolution. The experimental structure superimposed well with an Alphafold2Multimer prediction of the PP2A trimer. We then predicted models of all canonical PP2A complexes providing a framework for structural analysis of PP2A. In conclusion, methylation was dispensable for trimeric PP2A assembly and integrative structural biology studies of PP2A offered predictive models for all canonical PP2A complexes.

Metabolite Formation of Pesticide Isoprocarb in Coffee Beans During Short-Term Storage and Condition

Isoprocarb (IPC) is one of the most important carbamate pesticides for white flea control in coffee plants. The prevalence of isoprocarb pesticide residues in coffee, i.e., green coffee beans, is a cause for concern. Green coffee beans were intentionally contaminated with isoprocarb at concentrations >0.01 mg/kg, which was investigated in this research. Quantitative analysis of isoprocarb with the QuEChERS method and qualitative analysis for metabolite formation was characterized using UV-Vis, FTIR, 1H-NMR, GC-MS, and LC-QTOF-MS. Based on the data, the metabolite formed is o-cumenol through the hydrolysis reaction of o-aryl carbamate with the enzyme carboxylesterase. o-cumenol or 2- isopropylphenol as a phenol derivative. To verify the existence of metabolite analytes that are believed to be there in coffee tainted with isoprocarb, more reliable analytical techniques utilizing analytical standards must be developed. Isoprocarb concentrations decreased along the storage time, especially in unsterilized conditions. As a toxic compound, a quantitative structural activity relationship study (QSAR) was initially carried out through a software application for estimating toxicity (TEST) provided by the US Environmental Protection Agency (EPA). For additional information, based on the LC50 and LD50 data confirmed from the TEST application, it was concluded that isoprocarb is more toxic than o-cumenol.

Investigation of the structure and multi-stimuli-responsive behavior of ion-associated salt solvates of binary crystals

Investigation of the intermolecular interactions and crystal packing to understand crystal growth is a prime objective of crystal engineering. Solvent molecules within crystal assist the supramolecular aggregation, however, control over their lattice incorporation remains uncertain. In this work, we report three solvates of an ionic organic salt of a diazo-naphthol sulfonate (1) and 1,10-phenanthroline with one (2), three (3) and four (4) lattice water molecules. Attempts to isolate the dihydrate form were unsuccessful, while the monohydrate of 1 has been crystallised for comparative structural investigations. Structural studies reveal the existence of intriguing sulfonate-diazo intermolecular interactions responsible for centrosymmetric dimerization of the organosulfonate 1, which also persist in 2–4, validating higher preference and robustness of the synthon. Repetitive aggregation of the sulfonate-diazo interaction in 1 leads to the formation of linear π-stacked aggregate, which further aggregates through the lattice water molecules. The structural comparison indicates the preferential formation of the organo-sulfonate dimers in hydrated salts 2–4. Further, sandwich tetramers in 2 and 4 are formed by charge transfer interaction of the organo-sulfonate dimers with pyridinium coformer on either side, which are further associated by the lattice water molecules into disparately packed 3-dimensional supramolecules. The organo-sulfonates in 3 form a similar type of extended π-stacked chains as in 1, which are flanked by pyridinium ions to form hydrogen-bonded tapes, which are helped by the lattice water molecules to grow as segregated stacked layer solid. The characteristic absorption frequency of the diazo functionality is blue-shifted in infrared spectra of the cocrystal forms, indicating the presence of charge transfer interactions. The presence of dynamic solvent and protons in the lattice makes the solid forms multi-stimuli-responsive to exhibit mechano and vapochromic response. These phenomena have been studied in detail with the help of thermal, spectroscopic, and powder-diffraction studies.

The molecular principles underlying diverse functions of the SLC26 family of proteins

Mammalian SLC26 proteins are membrane-based anion transporters that belong to the large SLC26/SulP family, and many of their variants are associated with hereditary diseases. Recent structural studies revealed a strikingly similar homodimeric molecular architecture for several SLC26 members, implying a shared molecular principle. Now a new question emerges as to how these structurally similar proteins execute diverse physiological functions. In this study we sought to identify the common vs. distinct molecular mechanism among the SLC26 proteins using both naturally occurring and artificial missense changes introduced to SLC26A4, SLC26A5, and SLC26A9. We found: (i) the basic residue at the anion binding site is essential for both anion antiport of SLC26A4 and motor functions of SLC26A5, and its conversion to a nonpolar residue is crucial but not sufficient for the fast uncoupled anion transport in SLC26A9; (ii) the conserved polar residues in the N- and C-terminal cytosolic domains are likely involved in dynamic hydrogen-bonding networks and are essential for anion antiport of SLC26A4 but not for motor (SLC26A5) and uncoupled anion transport (SLC26A9) functions; (iii) the hydrophobic interaction between each protomer’s last transmembrane helices, TM14, is not of functional significance in SLC26A9 but crucial for the functions of SLC26A4 and SLC26A5, likely contributing to optimally orient the axis of the relative movements of the core domain with respect to the gate domains within the cell membrane. These findings advance our understanding of the molecular mechanisms underlying the diverse physiological roles of the SLC26 family of proteins.

HIV-1 Integrase Assembles Multiple Species of Stable Synaptic Complex Intasomes That Are Active for Concerted DNA Integration In vitro

Retroviral DNA integration is mediated by nucleoprotein complexes (intasomes) in which a pair of viral DNA ends are bridged by a multimer of integrase (IN). Most of the high-resolution structures of HIV-1 intasomes are based on an HIV-1 IN with an Sso7d protein domain fused to the N-terminus. Sso7d-IN aggregates much less than wild-type IN and has been critical for structural studies of HIV-1 intasomes. Unexpectedly, these structures revealed that the common core architecture that mediates catalysis could be assembled in various ways, giving rise to both tetrameric and dodecameric intasomes, together with other less well-characterized species. This differs from related retroviruses that assemble unique multimeric intasomes, although the number of protomers in the intasome varies between viruses. The question of whether the additional Sso7d domain contributes to the heterogeneity of HIV-1 intasomes is therefore raised. We have addressed this by biochemical and structural studies of intasomes assembled with wild-type HIV-1 IN. Negative stain and cryo-EM reveal a similar range of multimeric intasome species as with Sso7d-IN with the same common core architecture. Stacks of intasomes resulting from domain swapping are also seen with both wild-type and Sso7d-IN intasomes. The propensity to assemble multimeric intasome species is, therefore, an intrinsic property of HIV-1 IN and is not conferred by the presence of the Sso7d domain. The recently solved intasome structures of different retroviral species, which have been reported to be tetrameric, octameric, dodecameric, and hexadecameric, highlight how a common intasome core architecture can be assembled in different ways for catalysis.

A Janus carbaporphyrin pseudo-dimer

Carbaporphyrin dimers, investigated for their distinctive electronic structures and exceptional properties, have predominantly consisted of systems containing identical subunits. This study addresses the associated knowledge gap by focusing on asymmetric carbaporphyrin dimers with Janus-like characteristics. The synthesis of a Janus-type carbaporphyrin pseudo-dimer 5 is presented. It displays antiaromatic characteristics on the fused side and nonaromatic behavior on the unfused side. A newly synthesized tetraphenylene (TPE) linked bis-dibenzihomoporphyrin 8 and a previously reported dibenzo[g,p]chrysene (DBC) linked bis-dicarbacorrole 9 were prepared as controls. Comprehensive analyses, including 1H NMR spectral studies, single crystal X-ray diffraction analyses, and DFT calculations, validate the mixed character of 5. A further feature of the Janus pseudo-dimer 5 is that it may be transformed into a heterometallic complex, with one side coordinating a Cu(III) center and the other stabilizing a BODIPY complex. This disparate regiochemical reactivity underscores the potential of carbaporphyrin dimers as versatile frameworks, with electronic features and site-specific coordination chemistry controlled through asymmetry. These findings position carbaporphyrin dimers as promising candidates for advances in electronic structure studies, coordination chemistry, materials science, and beyond.

Assessing the infestation-induced response on the plant host by the Indian lac insect

Lac, the only natural resin of animal origin is produced by the Indian lac insect- Kerria lacca. It is the by-product of the complex natural interaction between the lac insect and its host plant. Despite several studies on the perspectives of the chemistry of lac and its production, very little work has been carried out to understand the biology of lac and its associated plant taxa. The present work has been designed to understand the preliminary response if any, of the host plant against lac insect infestation. Structural studies and metabolic profiling such as the determination of total phenolics, flavonoids, antioxidants, FTIR, and GC-MS were carried out. The anatomical investigations revealed coagulation/deposition of metabolites in the infested sites. The infested bark showed higher phenolic, flavonoid content, and antioxidant activity in comparison to non-infested bark which was corroborated by Fourier-transform infrared spectroscopy (FTIR) and GC-MS biochemical analysis. This preliminary study will shed some light on understanding the lac plant host's physiological response and the putative mechanism used by the lac insect in overcoming the plant response.

A Study of Occupational Structure in Kerala State Using GIS Techniques

Occupational structure is the distribution or division of working population in different sectors based on occupations. It is one of the key elements in manifestation of population composition of a region. The economy is segregated based on its occupational structure namely, the agriculture sector, industrial or manufacturing sector and service sector. Occupational structure provides clear picture of working and non-working population in an area. The growth and prosperity of a region largely depends on the size of working population and proportion of productive workers engaged in various economic activities. The objective of this study is to find out the shift in occupation from primary sector to other sectors and the rate of change in last two decades from 2001 to 2011 in Kerala state with district as spatial unit. The study is based upon the secondary data collected from Census 2001 and 2011.By using GIS techniques thematic maps were prepared to show the variation in occupational structure in the study area. To find out the changes in occupational structure, percentage of workers engaged in four categories are to be calculated. There is a remarkable shift of workers from agriculture to non-agricultural sector in Kerala.

Geological structure and petroleum systems of the Kazakhstan sector of the Caspian Sea South Mangyshlak sedimentary basin

This article discusses the results of a study of the geologic structure of Mesozoic sediments in the Kazakhstan sector of the Caspian Sea South Mangyshlak sedimentary basin. This paper includes an analysis of existing geological and geophysical data aimed at describing the characteristics of petroleum system elements. The main features of the sedimentation conditions of oil source rocks, reservoirs, and caps have been analyzed. The key hydrocarbon source zones in the territory of the Kazakhstan sector of the Caspian Sea have been determined. The correlation of existing wells to determine regional covers and main trends in reservoir sedimentation has been provided.

Molecular insights into capsular polysaccharide secretion.

Capsular polysaccharides (CPSs) fortify the cell boundaries of many commensal and pathogenic bacteria1. Through the ABC-transporter-dependent biosynthesis pathway, CPSs are synthesized intracellularly on a lipid anchor and secreted across the cell envelope by the KpsMT ABC transporter associated with the KpsE and KpsD subunits1,2. Here we use structural and functional studies to uncover crucial steps of CPS secretion in Gram-negative bacteria. We show that KpsMT has broad substrate specificity and is sufficient for the translocation of CPSs across the inner bacterial membrane, and we determine the cell surface organization and localization of CPSs using super-resolution fluorescence microscopy. Cryo-electron microscopy analyses of the KpsMT-KpsE complex in six different states reveal a KpsE-encaged ABC transporter, rigid-body conformational rearrangements of KpsMT during ATP hydrolysis and recognition of a glycolipid inside a membrane-exposed electropositive canyon. In vivo CPS secretion assays underscore the functional importance of canyon-lining basic residues. Combined, our analyses suggest a molecular model of CPS secretion by ABC transporters.

N-Heterocyclic Carbene to Actinide d-Based π-bonding Correlates with Observed Metal-Carbene Bond Length Shortening Versus Lanthanide Congeners.

Comparison of bonding and electronic structural features between trivalent lanthanide (Ln) and actinide (An) complexes across homologous series' of molecules can provide insights into subtle and overt periodic trends. Of keen interest and debate is the extent to which the valence f- and d-orbitals of trivalent Ln/An ions engage in covalent interactions with different ligand donor functionalities and, crucially, how bonding differences change as both the Ln and An series are traversed. Synthesis and characterization (SC-XRD, NMR, UV-vis-NIR, and computational modeling) of the homologous lanthanide and actinide N-heterocyclic carbene (NHC) complexes [M(C5Me5)2(X)(IMe4)] {X = I, M = La, Ce, Pr, Nd, U, Np, Pu; X = Cl, M = Nd; X = I/Cl, M = Nd, Am; and IMe4 = [C(NMeCMe)2]} reveals consistently shorter An-C vs Ln-C distances that do not substantially converge upon reaching Am3+/Nd3+ comparison. Specifically, the difference of 0.064(6) Å observed in the La/U pair is comparable to the 0.062(4) Å difference observed in the Nd/Am pair. Computational analyses suggest that the cause of this unusual observation is rooted in the presence of π-bonding with the valence d-orbital manifold in actinide complexes that is not present in the lanthanide congeners. This is in contrast to other documented cases of shorter An-ligand vs Ln-ligand distances, which are often attributed to increased 5f vs 4f radial diffusivity leading to differences in 4f and 5f orbital bonding involvement. Moreover, in these traditional observations, as the 5f series is traversed, the 5f manifold contracts such that by americium structural studies often find no statistically significant Am3+vs Nd3+ metal-ligand bond length differences.

Mapping talent pathways: A comparative study of developmental activities and practice structure in Brazilian and Spanish U-18 elite youth male soccer players

The purpose of this study was threefold: (1) to compare the engagement in various types and amounts of soccer activities during childhood and adolescence between Brazilian and Spanish elite youth soccer players; (2) to test what talent development pathway characterizes youth development in elite soccer in Brazil and Spain and (3) to compare the practice structure between elite youth soccer in Brazil and Spain. Participants were 131 U-18 elite male soccer players from Brazil ( n = 68) and Spain ( n = 63) competing in the national league. The Participant History Questionnaire was used to measure the soccer activities undertaken by players. Developmental activities were analyzed for two age periods: childhood (6–12 y/o) and early adolescence (13–15 y/o). In Spain, players started their involvement in practice and competition in soccer earlier compared to Brazilian players ( p < .05). Brazilian players were more involved in structured activities, such as practice in soccer and futsal, and participated in a greater number of sports in childhood and early adolescence ( p < .05). We found a very similar percentual practice structure (individual, pair, drills, group tactics and collective tactics activities) between Spain and Brazil, although Brazilian players accumulated a greater practice volume. It is concluded that Spanish and Brazilian U-18 elite youth male soccer players were differentiated by their milestones in soccer and their engagement in practice activities during childhood and early adolescence. Talent development pathway of male soccer players in Spain was characterized by the early engagement pathway, while the Brazilian system was characterized by the specialized sampling model.

Local Structure and Optical Studies of Mn2+ Doped L-histidine-4-nitrophenolate 4-nitrophenol Single Crystal

Background: The zero-field splitting parameters of Mn2+ doped L-histidine-4- nitrophenolate 4-nitrophenol single crystals are evaluated Methods: The superposition model and perturbation theory are used to obtain zero-field splitting parameters for Mn2+ ion-doped LHPP single crystals. The optical spectra of the system are computed using the crystal field parameters from the superposition model as input into the crystal field analysis program. Results: The evaluated zero field splitting parameters are in good match with the experimental values when local distortion is taken into account. The experimental finding that the Mn2+ ion enters the L-histidine-4-nitrophenolate 4-nitrophenol lattice at the interstitial position is supported by the theoretical result. Conclusion: It is found that the calculated and experimental band positions agree fairly well. Thus, the theoretical study supports the experimental observation.

Hypothalamic involvement in multiple system atrophy: A structural MRI study

ObjectiveTo investigate hypothalamic atrophy and its clinical correlates in multiple system atrophy (MSA) in-vivo. BackgroundMSA is characterized by autonomic dysfunction and parkinsonian/cerebellar manifestations. The hypothalamus regulates autonomic and homeostatic functions and is also involved in memory and learning processes. Methods11 MSA, 18 Parkinson's Disease (PD) and 18 Healthy Controls (HC) were included in this study. A validated and automated hypothalamic segmentation tool was applied to 3D-T1-weighted images acquired on a 3T MRI scanner. MSA hypothalamic volumes were compared to those of PD and HC. Furthermore, the association between hypothalamic volumes and scores of autonomic, depressive, sleep and cognitive manifestations were investigated. ResultsPosterior hypothalamus volume was reduced in MSA compared to controls (t = 2.105, p = 0.041) and PD (t = 2.055, p = 0.046). Total hypothalamus showed a trend towards a reduction in MSA vs controls (t = 1.676, p = 0.101). Reduced posterior hypothalamus volume correlated with worse MoCA scores in the parkinsonian (MSA + PD) group and in each group separately, but not with autonomic, sleep, or depression scores. ConclusionsIn-vivo structural hypothalamic involvement may be present in MSA. Reduced posterior hypothalamus volume, which includes the mammillary bodies and lateral hypothalamus, is associated with worse cognitive functioning. Larger studies on hypothalamic involvement in MSA and its clinical correlates are needed.