Hasil untuk "Biochemistry"

Catherine Kokemuller, Ryan Guldenpfennig, Clare Hsu et al.

Olive extract (OE) has been used in human foods for its nutraceutical effects, making it a product of interest for pet food. However, OE’s effect on palatability has not been examined. The study objective was to evaluate the palatability of dry cat foods with OE applied at differing inclusions within liquid or dry palatants. Twenty-seven volatile compounds were identified by gas chromatography–mass spectrometry for a potentially earthy or fruit-like flavor profile. Liquid palatants were formulated to supply 0 (control), 15, 30, 50, 75, and 150 ppm OE, and dry palatants were formulated to provide 0, 100, 200, 400, and 600 ppm OE when coated onto kibble. Palatability was evaluated using two-day, two-bowl testing of OE-containing versus control rations in adult cats (<i>n</i> = 20) with two-tailed <i>t</i>-tests to determine if OE affected intake ratio (IR). The observed IR of rations with OE were 0.45 to 0.56. The only preference was the 200 ppm treatment (IR = 0.56; <i>p</i> = 0.01) while the other OE rations were not different from the control (<i>p</i> ≥ 0.05). These findings indicate that palatant formulations can supply kibble diets with up to 150 ppm OE for liquid and 600 ppm for dry applications without negatively impacting cat food palatability.

Suzan A. Rahmtalla, Gad Allah Modawe, Abdelmula M. Abdalla et al.

Background: Previous studies suggest a significant relationship between type 2 diabetes mellitus (T2DM) and a lack of zinc. A lack of zinc can negatively impact insulin synthesis, storage, and secretion, leading to insulin resistance and inadequate glycaemic control. Nevertheless, the correlation between serum zinc levels and glycaemic control in T2DM has not been well studied in various populations. Objective: To investigate the relationship between serum zinc levels and glycaemic control, assessed by HbA1c, in individuals diagnosed with type 2 diabetes mellitus. Methods: This case-control study was carried out between April 2018 and July 2019 at Omdurman Teaching Hospital in Khartoum State, Sudan. The study included 100 participants: 50 were T2DM patients, and the other 50 were healthy individuals who served as controls. Serum zinc levels were determined with atomic absorption spectrophotometry, while HbA1c levels were evaluated with the Ichroma system. Data analysis was performed using SPSS, version 25. A comparative analysis was conducted on the groups, with correlation coefficients being calculated to investigate the correlations between age, serum zinc, and HbA1c levels. Results: The diabetics showed notably lower zinc levels in their blood compared to the control group, along with notably elevated HbA1c levels. In diabetic individuals, age correlated positively with HbA1c  and serum zinc levels. Additionally, diabetic patients showed a significant inverse correlation between their serum zinc levels and HbA1c values. Conclusion: This research indicates that individuals with diabetes might exhibit decreased zinc levels in their bloodstream and that a connection could exist between age, zinc levels in the bloodstream, and HbA1c levels in these individuals. The results of this research may impact how diabetes mellitus and zinc deficiency are managed.

Michael C Armstrong, Yannic R Weiß, Lila E Hoachlander-Hobby et al.

Abstract Rho GTPases form plasma membrane-associated patterns that control the cytoskeleton during cell division, morphogenesis, migration, and wound repair. Their patterning involves transitions between inactive cytosolic and active membrane-bound states, regulated by guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs), and guanine nucleotide dissociation inhibitors (GDIs). However, the relationships between these transitions and role of different regulators remain unclear. We developed a novel reconstitution approach to study Rho GTPase patterning with all major GTPase regulators in a biochemically defined system. We show that Rho GTPase dissociation from RhoGDI is rate-limiting for its membrane association. Rho GTPase activation occurs after membrane insertion, which is unaffected by GEF activity. Once activated, Rho GTPases are retained at the membrane through effector interactions, essential for their enrichment at activation sites. Thus, high cytosolic levels of RhoGDI-bound GTPases ensure a constant supply of inactive GTPases for the membrane, where GEF-mediated activation and effector binding stabilize them. These results delineate the route by which Rho GTPase patterns are established and define stage-dependent roles of its regulators.

Jia Xin Tang, Alfredo Cabrera-Orefice, Jana Meisterknecht et al.

The mitochondrial protein COA5 was previously reported as a complex IV assembly factor. Studying a further case of COA5-related mitochondrial disease, the authors delineate an essential role of this protein in the early stage of complex IV assembly. Pathogenic variants in cytochrome c oxidase assembly factor 5 (COA5), a proposed complex IV (CIV) assembly factor, have been shown to cause clinical mitochondrial disease with two siblings affected by neonatal hypertrophic cardiomyopathy manifesting a rare, homozygous COA5 missense variant (NM_001008215.3: c.157G>C, p.Ala53Pro). The most striking observation in the affected individuals was an isolated impairment in the early stage of mitochondrial CIV assembly. In this study, we report an unrelated family in whom we have identified the same COA5 variant with patient-derived fibroblasts and skeletal muscle biopsies replicating an isolated CIV deficiency. A CRISPR/Cas9-edited homozygous COA5 knockout U2OS cell line with a similar biochemical profile was generated to interrogate the functional role of the human COA5 protein. Mitochondrial complexome profiling pinpointed a role of COA5 in early CIV assembly, more specifically, its involvement in the stage between MTCO1 maturation and the incorporation of MTCO2. We therefore propose that the COA5 protein plays an essential role in the biogenesis of MTCO2 and its integration into the early CIV assembly intermediate for downstream assembly of the functional holocomplex.

Ekaterina Petushkova, Makhmadyusuf Khasimov, Ekaterina Mayorova et al.

The purple sulfur bacterium <i>Thiocapsa roseopersicina</i> BBS is interesting from both fundamental and practical points of view. It possesses a thermostable HydSL hydrogenase, which is involved in the reaction of reversible hydrogen activation and a unique reaction of sulfur reduction to hydrogen sulfide. It is a very promising enzyme for enzymatic hydrogenase electrodes. There are speculations that HydSL hydrogenase of purple bacteria is closely related to sulfur metabolism, but confirmation is required. For that, the full genome sequence is necessary. Here, we sequenced and assembled the complete genome of this bacterium. The analysis of the obtained whole genome, through an integrative approach that comprised estimating the Average Nucleotide Identity (ANI) and digital DNA-DNA hybridization (DDH) parameters, allowed for validation of the systematic position of <i>T. roseopersicina</i> as <i>T. bogorovii</i> BBS. For the first time, we have assembled the whole genome of this typical strain of a new bacterial species and carried out its functional description against another purple sulfur bacterium: <i>Allochromatium vinosum</i> DSM 180T. We refined the automatic annotation of the whole genome of the bacteria <i>T. bogorovii</i> BBS and localized the genomic positions of several studied genes, including those involved in sulfur metabolism and genes encoding the enzymes required for the TCA and glyoxylate cycles and other central metabolic pathways. Eleven additional genes coding proteins involved in pigment biosynthesis was found.

Agnij Bhattacharyya, Debadatta Chakrabarty, Anindya Mukherjee et al.

Background: The acceptance of the coronavirus disease 2019 (COVID-19) vaccination by the community was largely affected by information or misinformation spreading through various channels. Hence, in the process of deploying vaccines, it became important to explore the community&apos;s knowledge and attitude toward such intervention. Aims and Objectives: The aim of this study was to assess the knowledge, attitude, and practice toward COVID-19 vaccination among the general population of Kolkata and to compare knowledge, attitude, and practice toward COVID-19 vaccination among different groups based on age, gender, socioeconomic status, educational qualifications, and occupation. Materials and Methods: A descriptive cross-sectional study was carried out with 389 participants among the patients attending general outpatient department of a tertiary care hospital in Kolkata using a pre-tested questionnaire having sections on knowledge, attitude, and practices toward COVID-19 vaccination. Knowledge, attitude, and practice scores were then calculated and compared among different groups based on age, gender, socioeconomic status, educational qualifications, occupation, and history of COVID-19 infection. Results: Knowledge was found to differ significantly with respect to education, occupation, socioeconomic status, and history of COVID-19 infection. Attitude showed no variation to these variables, while practice scores were found to be significantly associated with education, socioeconomic status, and history of COVID-19 infection. The unavailability of slots for vaccination was not the reason for anyone remaining unvaccinated. Financial reasons were one of the factors determining vaccine hesitancy in parts of the world before vaccines were available. This study found that 72.8% of participants found vaccines to be inexpensive. Of the participants not having received even a single dose of vaccine, the most common reason was pregnancy and lactation-related issues. Conclusion: The reason behind such associations can be further explored in bigger multicentric studies. Improvement studies may also be carried out to assess the effectiveness of various channels of communication which may aid in figuring out lacunae and planning of similar vaccination drives in the future. [Natl J Physiol Pharm Pharmacol 2024; 14(1.000): 92-98]

Jisun Lee, Matthew C. Woodruff, Eui Ho Kim et al.

Abstract Since the discovery of messenger RNA (mRNA), there have been tremendous efforts to wield them in the development of therapeutics and vaccines. During the COVID-19 pandemic, two mRNA vaccines were developed and approved in record-breaking time, revolutionizing the vaccine development landscape. Although first-generation COVID-19 mRNA vaccines have demonstrated over 90% efficacy, alongside strong immunogenicity in humoral and cell-mediated immune responses, their durability has lagged compared to long-lived vaccines, such as the yellow fever vaccine. Although worldwide vaccination campaigns have saved lives estimated in the tens of millions, side effects, ranging from mild reactogenicity to rare severe diseases, have been reported. This review provides an overview and mechanistic insights into immune responses and adverse effects documented primarily for COVID-19 mRNA vaccines. Furthermore, we discuss the perspectives of this promising vaccine platform and the challenges in balancing immunogenicity and adverse effects.

Walaa S. Anwar, Fatma M. Abdel-maksoud, Ahmed M. Sayed et al.

Abstract Background Calamus rotang L. (CR) is an Indian shrub. The leaves and other organs of the plant are traditionally used in India for treatment of various diseases. The in vitro antioxidant property of the leaves extract was previously established. Thus, the current study aimed to evaluate the antioxidant and hepatoprotective effects of CR ethyl acetate extract at a dose of 350 mg/kg on CCl4 induced hepatotoxic rats through different mechanisms. Methods Histopathological examination of the treated rats’ group in comparison with positive and negative controls were performed. Quantitative measuring of the proinflammatory cytokines (TNF α), inflammatory regulators (Arginase, PPAR α) and the antiapoptotic protein Bcl-2 in comparison with positive and negative control groups was achieved using immunohistochemical examination. HPLC profiling of the polyphenol contents and molecular docking of the identified compounds against BH3 proapoptotic protein were correspondingly studied to evaluate the potential antiapoptotic property. Results The CR extract greatly protects the liver tissue through the suppression of TNF α, arginase and PPAR α induced by CCl4 as well as its enhancement of the antiapoptotic Bcl-2 protein. Fourteen polyphenols of different classes were identified in CR extract and tested via molecular docking for their potential antiapoptotic activities against BH3 protein. Naringin, rutin, 7-hydroxy flavone, and ellagic acid compounds exhibit the highest affinity and potential inhibition of pro-apoptotic protein BH3 via molecular docking study. Conclusions The ethyl acetate fraction of the leaves of C. rotang is rich in polyphenols that exhibited potent hepatoprotective effect on CCl4 induced hepatotoxic rats through its antioxidant, anti-inflammatory, anti-steatosis and antiapoptotic properties.

Xiaowen Lyu, M. Jordan Rowley, Michael J. Kulik et al.

Abstract Transcription reprogramming during cell differentiation involves targeting enhancers to genes responsible for establishment of cell fates. To understand the contribution of CTCF-mediated chromatin organization to cell lineage commitment, we analyzed 3D chromatin architecture during the differentiation of human embryonic stem cells into pancreatic islet organoids. We find that CTCF loops are formed and disassembled at different stages of the differentiation process by either recruitment of CTCF to new anchor sites or use of pre-existing sites not previously involved in loop formation. Recruitment of CTCF to new sites in the genome involves demethylation of H3K9me3 to H3K9me2, demethylation of DNA, recruitment of pioneer factors, and positioning of nucleosomes flanking the new CTCF sites. Existing CTCF sites not involved in loop formation become functional loop anchors via the establishment of new cohesin loading sites containing NIPBL and YY1 at sites between the new anchors. In both cases, formation of new CTCF loops leads to strengthening of enhancer promoter interactions and increased transcription of genes adjacent to loop anchors. These results suggest an important role for CTCF and cohesin in controlling gene expression during cell differentiation.

Abida Abida, Mikhlid H. Almutairi, Nadia Mushtaq et al.

Charles Brobbey, Shasha Yin, Liu Liu et al.

Abstract Protein arginine methyltransferase 5 (PRMT5) catalyzes mono-methylation and symmetric di-methylation on arginine residues and has emerged as a potential antitumor target with inhibitors being tested in clinical trials. However, it remains unknown how the efficacy of PRMT5 inhibitors is regulated. Here we report that autophagy blockage enhances cellular sensitivity to PRMT5 inhibitor in triple negative breast cancer cells. Genetic ablation or pharmacological inhibition of PRMT5 triggers cytoprotective autophagy. Mechanistically, PRMT5 catalyzes monomethylation of ULK1 at R532 to suppress ULK1 activation, leading to attenuation of autophagy. As a result, ULK1 inhibition blocks PRMT5 deficiency-induced autophagy and sensitizes cells to PRMT5 inhibitor. Our study not only identifies autophagy as an inducible factor that dictates cellular sensitivity to PRMT5 inhibitor, but also unearths a critical molecular mechanism by which PRMT5 regulates autophagy through methylating ULK1, providing a rationale for the combination of PRMT5 and autophagy inhibitors in cancer therapy.

Qianqiao Liu, Beth M. Stadtmueller

Abstract Immunoglobulin (Ig) A functions as monomeric IgA in the serum and Secretory (S) IgA in mucosal secretions. Host IgA Fc receptors (FcαRs), including human FcαR1/CD89, mediate IgA effector functions; however, human pathogen Streptococcus pyogenes has evolved surface-protein virulence factors, including M4, that also engage the CD89-binding site on IgA. Despite human mucosa serving as a reservoir for pathogens, SIgA interactions with CD89 and M4 remain poorly understood. Here we report cryo-EM structures of M4-SIgA and CD89-SIgA complexes, which unexpectedly reveal different SIgA-binding stoichiometry for M4 and CD89. Structural data, supporting experiments, and modeling indicate that copies of SIgA bound to S. pyogenes M4 will adopt similar orientations on the bacterium surface and leave one host FcαR binding site open. Results suggest unappreciated functional consequences associated with SIgA binding to host and bacterial FcαRs relevant to understanding host-microbe co-evolution, IgA effector functions and improving the outcomes of group A Streptococcus infection.

Zhipu Luo, Weijie Gu, Yichao Wang et al.

Heavy-atom soaking has been a major method for experimental phasing, but it has been difficult for membrane proteins, partly owing to the lack of available sites in the scarce soluble domain for non-invasive heavy-metal binding. The lipid cubic phase (LCP) has proven to be a successful method for membrane protein crystallization, but experimental phasing with LCP-grown crystals remains difficult, and so far, only 68 such structures were phased experimentally. Here, the selenourea was tested as a soaking reagent for the single-wavelength anomalous dispersion (SAD) phasing of crystals grown in LCP. Using a single crystal, the structure of the glycerol 3-phosphate acyltransferase (PlsY, ~21 kDa), a very hydrophobic enzyme with 80% membrane-embedded residues, was solved. Remarkably, a total of 15 Se sites were found in the two monomers of PlsY, translating to one selenourea-binding site per every six residues in the accessible extramembrane protein. Structure analysis reveals that surface-exposed selenourea sites are mostly contributed by mainchain amides and carbonyls. This low-specificity binding pattern may explain its high loading ratio. Importantly, both the crystal diffraction quality and the LCP integrity were unaffected by selenourea soaking. Taken together, selenourea presents a promising and generally useful reagent for heavy-atom soaking of membrane protein crystals grown in LCP.

Abraham J.P. Teunissen, Omar B. Abousaway, Jazz Munitz et al.

Summary: Noninvasive immunoimaging holds great potential for studying and stratifying disease as well as therapeutic efficacy. Radiolabeled single-domain antibody fragments (i.e., nanobodies) are appealing probes for immune landscape profiling, as they display high stability, rapid targeting, and excellent specificity, while allowing extremely sensitive nuclear readouts. Here, we present a protocol for radiolabeling an anti-CD11b nanobody and studying its uptake in mice by a combination of positron emission tomography imaging, ex vivo gamma counting, and autoradiography. Our protocol is applicable to nanobodies against other antigens.For complete details on the use and execution of this protocol, please see Priem et al. (2020), Senders et al. (2019), or Rashidian et al. (2017).

Jeffrey M. Rabin, Adam Burgasser, Thomas J. Bussey et al.

Abstract Rate of change concepts from calculus are presented and applied rather differently in college mathematics, physics, biology, and chemistry classes. This is not simply a matter of pedagogical style but reflects real cultural differences between these disciplines. We describe the efforts of our interdisciplinary collaboration to understand and reconcile these differences as we designed and discussed instructional videos for students. We summarize our conversations about terminology, notation, functions, rates, units, and sign conventions across the disciplines. We present some strategies that enabled us to communicate effectively, resolve confusions, and reach shared understandings. Our work has implications for others involved in collaborative interdisciplinary projects and for STEM educators. In theory, there’s no difference between theory and practice. But in practice, there is. – Benjamin Brewster. Also attributed to Yogi Berra.

Elsayed E. I., Mossad W.G., Ismail A.H. et al.

One of the effective recommendation for control of Foot and Mouth disease virus is the proper vaccination by a highly potent vaccine. Such a vaccine should be specific to the circulated field serotype of foot and mouth disease virus inducing rapid, highly protective immunity with a long duration. This research is concerned with using plant extracted oil adjuvants prepared from rapeseed oil mixed with or without Ginseng extracts and from Soybean oil as well with or without Ginseng extracts. Some humoral and cellular immune responses were compared using the different plant-extracted oils and the mineral-based adjuvant called Montanide oil ISA 206 after one dose vaccination of the prepared vaccines at different interval times post vaccinations. Lymphocyte blastogenesis, Interleukin-6, and Interleukin-12 showed higher expression in calves vaccinated by FMDV serotypes (O pan Asia, A Iran O5, and SAT2 / EGY/2012) with plant extract oil containing Ginseng extract comparable to that of plant extracts without Ginseng and Montanide oil ISA 206 adjuvants vaccines. It was found that FMD vaccine adjuvant with ginseng either with rapeseed or Soybean showed a higher post vaccinal cellular immune response than that without ginseng or ISA 206 alone. Estimation of the humoral immune response of vaccinated calves revealed that antibody against FMD virus serotypes O pan Asia, A Iran O5 and SAT2 / EGY/2012 by SNT and ELISA assay induced by the inactivated FMD adjuvant with rapeseed oil and ginseng vaccine and the inactivated FMD adjuvant with soybean oil and ginseng vaccine were higher than those induced by inactivated FMD adjuvant with Montanide oils 206. In contrast, the obtained antibody levels by the inactivated FMD adjuvant with rapeseed oil vaccine and inactivated FMD adjuvant with soybean oil vaccine was lower than those induced by inactivated FMD adjuvant with Montanide oils 206. So, it could be concluded that the use of plant origin oil adjuvant as rapeseed and soybean oil is considered a beneficial and alternative adjuvant to the imported mineral oil as it is much cheaper and induce better post vaccinal immune responses especially when mixed with ginseng extract.

Raghupathy Vengoji, Muzafar A. Macha, Rama Krishna Nimmakayala et al.

Abstract Background Glioblastoma (GBM) is an aggressive brain tumor with universal recurrence and poor prognosis. The recurrence is largely driven by chemoradiation resistant cancer stem cells (CSCs). Epidermal growth factor receptor (EGFR) and its mutant EGFRvIII are amplified in ~ 60% and ~ 30% of GBM patients, respectively; however, therapies targeting EGFR have failed to improve disease outcome. EGFRvIII-mediated cross-activation of tyrosine kinase receptor, cMET, regulates GBM CSC maintenance and promote tumor recurrence. Here, we evaluated the efficacy of pan-EGFR inhibitor afatinib and Temozolomide (TMZ) combination on GBM in vitro and in vivo. Methods We analyzed the effect of afatinib and temozolomide (TMZ) combination on GBM cells U87MG and U251 engineered to express wild type (WT) EGFR, EGFRvIII or EGFRvIII dead kinase, CSCs isolated from U87 and U87EGFRvIII in vitro. The therapeutic utility of the drug combination was investigated on tumor growth and progression using intracranially injected U87EGFRvIII GBM xenografts. Results Afatinib and TMZ combination synergistically inhibited the proliferation, clonogenic survival, motility, invasion and induced senescence of GBM cells compared to monotherapy. Mechanistically, afatinib decreased U87EGFRvIII GBM cell proliferation and motility/invasion by inhibiting EGFRvIII/AKT, EGFRvIII/JAK2/STAT3, and focal adhesion kinase (FAK) signaling pathways respectively. Interestingly, afatinib specifically inhibited EGFRvIII-cMET crosstalk in CSCs, resulting in decreased expression of Nanog and Oct3/4, and in combination with TMZ significantly decreased their self-renewal property in vitro. More interestingly, afatinib and TMZ combination significantly decreased the xenograft growth and progression compared to single drug alone. Conclusion Our study demonstrated significant inhibition of GBM tumorigenicity, CSC maintenance in vitro, and delayed tumor growth and progression in vivo by combination of afatinib and TMZ. Our results warrant evaluation of this drug combination in EGFR and EGFRvIII amplified GBM patients.

J. Drake, R. H. Baltz

B. Vallée

Kwasi M. Connor, Aaron Sung, Nathan S. Garcia et al.

The intertidal mussel Mytilus californianus is a critical foundation species that is exposed to fluctuations in the environment along tidal- and wave-exposure gradients. We investigated feeding and digestion in mussels under laboratory conditions and across environmental gradients in the field. We assessed whether mussels adopt a rate-maximization (higher ingestion and lower assimilation) or a yield-maximization acquisition (lower ingestion and higher assimilation) strategy under laboratory conditions by measuring feeding physiology and digestive enzyme activities. We used digestive enzyme activity to define resource acquisition strategies in laboratory studies, then measured digestive enzyme activities in three microhabitats at the extreme ends of the tidal- and wave-exposure gradients within a stretch of shore (<20 m) projected sea-ward. Our laboratory results indicated that mussels benefit from a high assimilation efficiency when food concentration is low and have a low assimilation efficiency when food concentration is high. Additionally, enzyme activities of carbohydrases amylase, laminarinase and cellulase were elevated when food concentration was high. The protease trypsin, however, did not increase with increasing food concentration. In field conditions, low-shore mussels surprisingly did not have high enzyme activities. Rather, high-shore mussels exhibited higher cellulase activities than low-shore mussels. Similarly, trypsin activity in the high-shore-wave-sheltered microhabitat was higher than that in high-shore-wave-exposed. As expected, mussels experienced increasing thermal stress as a function of reduced submergence from low to high shore and shelter from wave-splash. Our findings suggest that mussels compensate for limited feeding opportunities and thermal stress by modulating digestive enzyme activities.