Environmentally Friendly Approach to Pectin Extraction from Grapefruit Peel: Microwave-Assisted High-Pressure CO2/H2O.

In this research, pectin extraction from grapefruit peel (GPP) was performed using a microwave-assisted high-pressure CO2/H2O (MW-HPCO2) system. The Box-Behnken design of response surface methodology was applied for the optimization of MW-HPCO2 extraction conditions to obtain the highest pectin yield. The effects of temperature, time, and liquid/solid ratio on pectin yield were examined in the range of 100-150 °C, 5-15 min, and 10-20 mL g-1, respectively. Under the optimum extraction conditions (147 °C, 3 min, and 10 mL g-1), pectin was obtained with a yield of 27.53%. The results obtained showed that the extraction temperature and time had a strong effect on the pectin yield, while the effect of the liquid/solid ratio was not significant, and the pectin was effectively extracted from grapefruit peel (GP) using MW-HPCO2. Additionally, the application of GPP in apricot jam showed that MW-HPCO2-GPP can be used as a thickener in the food industry. The yield and physicochemical properties (ash, protein, galacturonic acid, reducing sugar and methoxyl content, degree of esterification, equivalent weight, color, viscosity) of pectin extracted in the optimum conditions of the MW-HPCO2 method were superior to pectin extracted by the traditional method. The results of this study revealed that MW-HPCO2 could be an innovative green and rapid technique for pectin extraction.

Impact of climate change and land cover dynamics on nitrate transport to surface waters.

The study investigated the impact of climate and land cover change on water quality. The novel contribution of the study was to investigate the individual and combined impacts of climate and land cover change on water quality with high spatial and temporal resolution in a basin in Turkey. The global circulation model MPI-ESM-MR was dynamically downscaled to 10-km resolution under the RCP8.5 emission scenario. The Soil and Water Assessment Tool (SWAT) was used to model stream flow and nitrate loads. The land cover model outputs that were produced by the Land Change Modeler (LCM) were used for these simulation studies. Results revealed that decreasing precipitation intensity driven by climate change could significantly reduce nitrate transport to surface waters. In the 2075-2100 period, nitrate-nitrogen (NO3-N) loads transported to surface water decreased by more than 75%. Furthermore, the transition predominantly from forestry to pastoral farming systems increased loads by about 6%. The study results indicated that fine-resolution land use and climate data lead to better model performance. Environmental managers can also benefit greatly from the LCM-based forecast of land use changes and the SWAT model's attribution of changes in water quality to land use changes.

COVID-19 in Children with Chronic Kidney Disease; Does it Differ Much?

BACKGROUND: COVID-19 is known to have a mild course in children, however more data on pediatric chronic kidney disease (CKD) is needed. We aimed to assess the incidence and severity of COVID-19 in pediatric CKD patients. METHODS: A questionnaire including demographics, COVID-19 history, symptoms, and vaccination status was applied to patients with CKD. We also retrospectively reviewed the presentation and outcomes of SARS-CoV-2 infection in this patient group from March 2020 to December 2021. RESULTS: 220 patients were included, 48 were found to have experienced COVID-19. There was no significant difference regarding age, gender, underlying kidney disease, CKD stage, dialysis status, type or number of immunosuppressive medications, and glomerular filtration rate between patients with and without COVID-19. Most were infected by a household member (43.8%) and during outpatient or inpatient care (18.8%). Four (8.3%) were asymptomatic, and 43 (89.6%) had mild infection. Severe COVID-19 was observed in only one patient. Eleven (22.9%) patients with COVID-19 were previously vaccinated. Acute kidney injury was detected in 4 (8.3%); as stage 1 in all. Median follow-up after COVID-19 was 4.6 months. All patients fully recovered, and no renal disease flare or death was observed. CONCLUSIONS: Although the vaccination rate was low in our cohort, the majority of the children with COVID-19 showed a mild course. Along with the vaccination, general precautions seemed to be successful for this population.

Acute kidney injury in children with moderate-severe COVID-19 and multisystem inflammatory syndrome in children: a referral center experience.

BACKGROUND: Data on the characteristics of acute kidney injury (AKI) in pediatric COVID-19 and MIS-C are limited. We aimed to define the frequency, associated factors and early outcome of AKI in moderate, severe or critical COVID-19 and MIS-C; and to present a tertiary referral center experience from Türkiye. METHODS: Hospitalized patients ≤ 18 years of age with confirmed COVID-19 or MIS-C at Ihsan Dogramaci Children's Hospital, Hacettepe University, between March 2020-December 2021 were enrolled. The characteristics of AKI in the COVID-19 group were investigated in moderate, severe and critically ill patients; patients with mild COVID-19 were excluded. RESULTS: The median (Q1-Q3) age in the COVID-19 (n = 66) and MIS-C (n = 111) groups was 10.7 years (3.9-15.2) and 8.7 years (4.5-12.7), respectively. The frequency of AKI was 22.7% (15/66) in COVID-19 and 15.3% (17/111) in MIS-C; all MIS-C patients with AKI and 73.3% (11/15) of COVID-19 patients with AKI had AKI at the time of admission. Multivariate analyses revealed need for vasoactive/inotropic agents [Odds ratio (OR) 19.233, p = 0.002] and presence of vomiting and/or diarrhea (OR 4.465, p = 0.036) as independent risk factors of AKI in COVID-19 patients; and need for vasoactive/inotropic agents (OR 22.542, p = 0.020), procalcitonin and ferritin levels as independent risk factors of AKI in the MIS-C group. Age was correlated with lymphocyte count (r = -0.513, p < 0.001) and troponin level (r = 0.518, p < 0.001) in MIS-C patients. Length of hospital stay was significantly longer in both groups with AKI, compared to those without AKI. Mortality was 9.1% in the COVID-19 group; and was associated with AKI (p = 0.021). There was no mortality in MIS-C patients. AKI recovery at discharge was 63.6% in COVID-19 survivors and 100% in MIS-C patients. CONCLUSIONS: Independent risk factors for AKI were need for vasoactive/inotropic agents and vomiting/diarrhea in moderate, severe or critical COVID-19 patients; and need for vasoactive/inotropic agents and severe inflammation in MIS-C patients. Our findings suggest that inflammation and cardiac dysfunction are associated with AKI in MIS-C patients; and the association with age in this group merits further studies in larger groups. Early outcome is favorable; long-term follow-up for kidney functions is needed.

Martini 3 Coarse-Grained Force Field for Cholesterol.

Cholesterol plays a crucial role in biomembranes by regulating various properties, such as fluidity, rigidity, permeability, and organization of lipid bilayers. The latest version of the Martini model, Martini 3, offers significant improvements in interaction balance, molecular packing, and inclusion of new bead types and sizes. However, the release of the new model resulted in the need to reparameterize many core molecules, including cholesterol. Here, we describe the development and validation of a Martini 3 cholesterol model, addressing issues related to its bonded setup, shape, volume, and hydrophobicity. The proposed model mitigates some limitations of its Martini 2 predecessor while maintaining or improving the overall behavior.

Endovascular Treatment of a Giant Aneurysm of the Aberrant Right Hepatic Artery in a Patient with Osler-Weber-Rendu Syndrome: A Case Report.

Osler-Weber-Rendu syndrome (OWR) is an autosomal dominant disorder characterized by recurrent epistaxis, mucocutaneous or visceral telangiectasias, and arteriovenous malformations in the lungs, liver, brain, and gastrointestinal tract. Hepatic artery aneurysms (HAAs) can also occur in OWR patients. HAAs are the second most common type of visceral artery aneurysm, and mortality rates are high owing to the lack of a tamponade effect. Anatomical variations of the celiacomesenteric vasculature are common, and the most common variation is that of the right hepatic artery originating from the superior mesenteric artery (SMA). We present the endovascular treatment of a patient with OWR and an aberrant right HAA originating from the SMA, with coil embolization and stent grafting. Giant HAAs can be treated endovascularly. However, stent graft placement should be reconsidered because of the need for antithrombotic medication, which may increase the incidence of epistaxis attacks in that patient group.

A single-molecule method for measuring fluorophore labeling yields for the study of membrane protein oligomerization in membranes.

Membrane proteins are often observed as higher-order oligomers, and in some cases in multiple stoichiometric forms, raising the question of whether dynamic oligomerization can be linked to modulation of function. To better understand this potential regulatory mechanism, there is an ongoing effort to quantify equilibrium reactions of membrane protein oligomerization directly in membranes. Single-molecule photobleaching analysis is particularly useful for this as it provides a binary readout of fluorophores attached to protein subunits at dilute conditions. However, any quantification of stoichiometry also critically requires knowing the probability that a subunit is fluorescently labeled. Since labeling uncertainty is often unavoidable, we developed an approach to estimate labeling yields using the photobleaching probability distribution of an intrinsic dimeric control. By iterative fitting of an experimental dimeric photobleaching probability distribution to an expected dimer model, we estimate the fluorophore labeling yields and find agreement with direct measurements of labeling of the purified protein by UV-VIS absorbance before reconstitution. Using this labeling prediction, similar estimation methods are applied to determine the dissociation constant of reactive CLC-ec1 dimerization constructs without prior knowledge of the fluorophore labeling yield. Finally, we estimate the operational range of subunit labeling yields that allows for discrimination of monomer and dimer populations across the reactive range of mole fraction densities. Thus, our study maps out a practical method for quantifying fluorophore labeling directly from single-molecule photobleaching data, improving the ability to quantify reactive membrane protein stoichiometry in membranes.

A rare cause of nephrotic syndrome-sphingosine-1-phosphate lyase (SGPL1) deficiency: 6 cases and a review of the literature.

BACKGROUND: Recently, recessive mutations in SGPL1 (sphingosine-1-phosphate lyase), which encodes the final enzyme of sphingolipid metabolism, have been reported to cause steroid-resistant nephrotic syndrome, adrenal insufficiency, and many other organ/system involvements. We aimed to determine the clinical and genetic characteristics, and outcomes in patients with SGPL1 mutations. METHODS: The study included 6 patients with bi-allelic SGPL1 mutation. Clinical, genetic, and laboratory characteristics, and outcomes of the patients were evaluated retrospectively. We also reviewed previously reported patients with SGPL1 mutations and compared them to the presented patients. RESULTS: The median age at kidney presentation was 5 months. Four patients (67%) were diagnosed before age 1 year. Kidney biopsy showed focal segmental glomerulosclerosis in 2 patients and diffuse mesangial sclerosis in one patient. Steroids were given to 3 patients, but they did not respond. All 6 patients progressed to chronic kidney disease; 5 required kidney replacement therapy (KRT) at a median age of 6 months. Deceased kidney transplantation was performed in one patient. All 6 patients had adrenal insufficiency, of which 5 were diagnosed at age < 6 months. Three patients had hypothyroidism, 2 had ichthyosis, 4 had immunodeficiency, 5 had neurological findings, and 2 had genitourinary system anomalies. Four patients died at a median age of 30.5 months. Two patients are being followed up with KRT. One patient had a novel mutation. CONCLUSIONS: Patients with SGPL1 mutations have a poor prognosis, and many types of extrarenal organ/system involvement beyond adrenal insufficiency can be seen. Genetic diagnosis of such patients is important for treatment, genetic counseling, and screening for comorbid conditions. A higher resolution version of the Graphical abstract is available as Supplementary information.

Structural Determinants and Functional Significance of Dimerization for Osmosensing Transporter ProP in Escherichia coli.

Osmosensing transporter ProP forestalls cellular dehydration by detecting environments with high osmotic pressure and mediating the accumulation of organic osmolytes by bacterial cells. It is composed of 12 transmembrane helices with cytoplasmic N- and C-termini. In Escherichia coli, dimers form when the C-terminal domains of ProP molecules form homodimeric, antiparallel, α-helical coiled coils. No dominant negative effect was detected when inactive and active ProP molecules formed heterodimers in vivo. Purification of ProP in detergent dodecylmaltoside yielded monomers, which were functional after reconstitution in proteoliposomes. With other evidence, this suggests that ProP monomers function independently whether in the monomeric or dimeric state. Amino acid replacements that disrupted or reversed the coiled coil did not prevent in vivo dimerization of ProP detected with a bacterial two-hybrid system. Maleimide labeling detected no osmolality-dependent variation in the reactivities of cysteine residues introduced to transmembrane helix (TM) XII. In contrast, coarse-grained molecular dynamic simulations detected deformation of the lipid around TMs III and VI, on the lipid-exposed protein surface opposite to TM XII. This suggests that the dimer interface of ProP includes the surfaces of TMs III and VI, not of TM XII as previously suggested by crosslinking data. Homology modeling suggested that coiled-coil formation and dimerization via such an interface are not mutually exclusive. In previous work, alterations to the C-terminal coiled coil blocked co-localization of ProP with phospholipid cardiolipin at E. coli cell poles. Thus, dimerization may contribute to ProP targeting, adjust its lipid environment, and hence indirectly modify its osmotic stress response.

Ion behavior in the selectivity filter of HCN1 channels.

Hyperpolarization-activated cyclic-nucleotide gated channels (HCNs) are responsible for the generation of pacemaker currents (If or Ih) in cardiac and neuronal cells. Despite the overall structural similarity to voltage-gated potassium (Kv) channels, HCNs show much lower selectivity for K+ over Na+ ions. This increased permeability to Na+ is critical to their role in membrane depolarization. HCNs can also select between Na+ and Li+ ions. Here, we investigate the unique ion selectivity properties of HCNs using molecular-dynamics simulations. Our simulations suggest that the HCN1 pore is flexible and dilated compared with Kv channels with only one stable ion binding site within the selectivity filter. We also observe that ion coordination and hydration differ within the HCN1 selectivity filter compared with those in Kv and cyclic-nucleotide gated channels. Additionally, the C358T mutation further stabilizes the symmetry of the binding site and provides a more fit space for ion coordination, particularly for Li+.

Neurologic manifestations in children with COVID-19 from a tertiary center in Turkey and literature review.

BACKGROUND: Since December 2019, coronavirus disease 2019 (COVID-19) has become a global pandemic caused by highly transmissible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although respiratory disease and multisystem inflammatory syndrome in children (MIS-C) are main clinical presentations in children, numerous neurological manifestations are being described increasingly. We aimed to investigate new onset neurological symptoms associated with SARS-CoV-2 in pediatric patients in order to establish a possible relationship as well as to understand the underlying pathophysiological mechanisms between SARS-CoV-2 infection and neurological findings. METHODS: We analyzed retrospectively children who had neurologic manifestations temporally associated with SARS-CoV-2 infection at Hacettepe University Ihsan Dogramaci Children's Hospital. We performed a literature search between March 20, 2020 and March 30, 2021. Articles that report children with COVID-19 related neurological manifestations were included. RESULTS: We have observed 15 consecutive cases with new onset neurological manifestations along with confirmed SARS-CoV-2 infection. Age at hospitalization ranged from three months to 17 years. Ten patients had central nervous system involvement, and most common manifestation was encephalopathy (5/10), which is also one of the most common manifestations of the patients mentioned in the relevant 39 articles we reviewed. CONCLUSION: Children with COVID-19 can present with neurologic findings such as encephalopathy, seizures, cerebrovascular events as well as abnormal eye movements. Clinical suspicion and awareness are required to show the association between neurologic manifestations and COVID-19.

Mitigation of portal fibrosis and cholestatic liver disease in ANKS6-deficient livers by macrophage depletion.

Congenital hepatic fibrosis (CHF) is a developmental liver disease that is caused by mutations in genes that encode ciliary proteins and is characterized by bile duct dysplasia and portal fibrosis. Recent work has demonstrated that mutations in ANKS6 can cause CHF due to its role in bile duct development. Here, we report a novel ANKS6 mutation, which was identified in an infant presenting with neonatal jaundice due to underlying biliary abnormalities and liver fibrosis. Molecular analysis revealed that ANKS6 liver pathology is associated with the infiltration of inflammatory macrophages to the periportal fibrotic tissue and ductal epithelium. To further investigate the role of macrophages in CHF pathophysiology, we generated a novel liver-specific Anks6 knockout mouse model. The mutant mice develop biliary abnormalities and rapidly progressing periportal fibrosis reminiscent of human CHF. The development of portal fibrosis in Anks6 KO mice coincided with the accumulation of inflammatory monocytes and macrophages in the mutant liver. Gene expression and flow cytometric analysis demonstrated the preponderance of M1- over M2-like macrophages at the onset of fibrosis. A critical role for macrophages in promoting peribiliary fibrosis was demonstrated by depleting the macrophages with clodronate liposomes which effectively reduced inflammatory gene expression and fibrosis, and ameliorated tissue histology and biliary function in Anks6 KO livers. Together, this study demonstrates that macrophages play an important role in the initiation of liver fibrosis in ANKS6-deficient livers and their therapeutic elimination may provide an avenue to mitigate CHF in patients.

A splice site mutation in the TSEN2 causes a new syndrome with craniofacial and central nervous system malformations, and atypical hemolytic uremic syndrome.

Recessive mutations in the genes encoding the four subunits of the tRNA splicing endonuclease complex (TSEN54, TSEN34, TSEN15, and TSEN2) cause various forms of pontocerebellar hypoplasia, a disorder characterized by hypoplasia of the cerebellum and the pons, microcephaly, dysmorphisms, and other variable clinical features. Here, we report an intronic recessive founder variant in the gene TSEN2 that results in abnormal splicing of the mRNA of this gene, in six individuals from four consanguineous families affected with microcephaly, multiple craniofacial malformations, radiological abnormalities of the central nervous system, and cognitive retardation of variable severity. Remarkably, unlike patients with previously described mutations in the components of the TSEN complex, all the individuals that we report developed atypical hemolytic uremic syndrome (aHUS) with thrombotic microangiopathy, microangiopathic hemolytic anemia, thrombocytopenia, proteinuria, severe hypertension, and end-stage kidney disease (ESKD) early in life. Bulk RNA sequencing of peripheral blood cells of four affected individuals revealed abnormal tRNA transcripts, indicating an alteration of the tRNA biogenesis. Morpholino-mediated skipping of exon 10 of tsen2 in zebrafish produced phenotypes similar to human patients. Thus, we have identified a novel syndrome accompanied by aHUS suggesting the existence of a link between tRNA biology and vascular endothelium homeostasis, which we propose to name with the acronym TRACK syndrome (TSEN2 Related Atypical hemolytic uremic syndrome, Craniofacial malformations, Kidney failure).