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Publication
Journal: Frontiers in Chemistry
April/26/2019
Abstract
The synthesis of oligosaccharides and other carbohydrate derivatives is of relevance for the advancement of glycosciences both at the fundamental and applied level. For many years, glycosyl hydrolases (GHs) have been explored to catalyze the synthesis of glycosidic bonds. In particular, retaining GHs can catalyze a transglycosylation (T) reaction that competes with hydrolysis (H). This has been done either employing controlled conditions in wild type GHs or by engineering new mutants. The goal, which is to increase the T/H ratio, has been achieved with moderate success in several cases despite the fact that the molecular basis for T/H modulation are unclear. Here we have used QM(DFT)/MM calculations to compare the glycosylation, hydrolysis and transglycosylation steps catalyzed by wild type Thermus thermophilus β-glycosidase (family GH1), a retaining glycosyl hydrolase for which a transglycosylation yield of 36% has been determined experimentally. The three transition states have a strong oxocarbenium character and ring conformations between 4H3 and 4E. The atomic charges at the transition states for hydrolysis and transglycosylation are very similar, except for the more negative charge of the oxygen atom of water when compared to that of the acceptor Glc. The glycosylation transition state has a stronger S N 2 character than the deglycosylation ones and the proton transfer is less advanced. At the QM(PBE0/TZVP)/MM level, the TS for transglycosylation has shorter O4GLC-C1FUC (forming bond) distance and longer OE2GLU338-C1FUC (breaking) distance than the hydrolysis one, although the HACC proton is closer to the Glu164 base in the hydrolysis TS. The QM(SCC-DFTB)/MM free energy maxima show the inverted situation, although the hydrolysis TS presents significant structural fluctuations. The 3-OHGLC group of the acceptor Glc (transglycosylation) and WAT432 (neighbor water in hydrolysis) are identified to stabilize the oxocarbenium transition states through interaction with O5FUC and O4FUC. The analysis of interaction suggests that perturbing the Glu392-Fuc interaction could increase the T/H ratio, either by direct mutation of this residue or indirectly as reported experimentally in the Asn390I and Phe401S cases. The molecular understanding of similarities and differences between hydrolysis and transglycosylation steps may be of help in the design of new biocatalysts for glycan synthesis.
Publication
Journal: Bioresource Technology
October/16/2013
Abstract
The study investigated the β-glucosidase-producing microbial communities and the enzymatic dynamics of CMCase and β-glucosidase during the process of cattle manure-rice straw composting. In order to analyze the succession of functional community by PCR-denaturing gradient gel electrophoresis (DGGEs), three sets of PCR primers were designed to amplify the family 1 and 3 β-glucosidase genes from both bacteria and fungi. The results showed in general that the stable functional community composition as well as for the high level enzymatic activities of both cellulase and β-glucosidase occurred during the last phase (days 14-31) of composting. In the process of composting, that functional groups were determined by the stable bands (GH1-F, GH1-H, GH1-G, GH3E-D and GH3E-E) may significantly contribute to the increase of β-glucosidase activities in the later phase. Especially, the bands from the family 1 β-glucosidase genes were appeared before that from the family 3 β-glucosidase genes from fungi, then the former was substituted for the latter gradually in the cooling phase. We found significant correlations between the β-glucosidase activity and the communities of the functional bacteria and fungi. The results indicated that different β-glucosidase-producing microbe release different amounts or activities of β-glucosidase, and that the composition of microbial communities may play a major role in determining overall β-glucosidase activity during the composting process.
Publication
Journal: Canadian Journal of Microbiology
November/15/2017
Abstract
The composting ecosystem is a suitable source for the discovery of novel microorganisms and secondary metabolites. Cellulose degradation is an important part of the global carbon cycle, and β-glucosidases complete the final step of cellulose hydrolysis by converting cellobiose to glucose. This work analyzes the succession of β-glucosidase-producing microbial communities that persist throughout cattle manure - rice straw composting, and evaluates their metabolic activities and community advantage during the various phases of composting. Fungal and bacterial β-glucosidase genes belonging to glycoside hydrolase families 1 and 3 (GH1 and GH3) amplified from DNA were classified and gene abundance levels were analyzed. The major reservoirs of β-glucosidase genes were the fungal phylum Ascomycota and the bacterial phyla Firmicutes, Actinobacteria, Proteobacteria, and Deinococcus-Thermus. This indicates that a diverse microbial community utilizes cellobiose. The succession of dominant bacteria was also detected during composting. Firmicutes was the dominant bacteria in the thermophilic phase of composting; there was a shift to Actinomycetes in the maturing stage. Proteobacteria accounted for the highest proportions during the heating and thermophilic phases of composting. By contrast, the fungal phylum Ascomycota was a minor microbial community constituent in thermophilic phase of composting. Combined with the analysis of the temperature, cellulose degradation rate and the carboxymethyl cellulase and β-glucosidase activities showed that the bacterial GH1 family β-glucosidase genes make greater contribution in cellulose degradation at the later thermophilic stage of composting. In summary, even GH1 bacteria families β-glucosidase genes showing low abundance in DNA may be functionally important in the later thermophilic phase of composting. The results indicate that a complex community of bacteria and fungi expresses β-glucosidases in compost. Several β-glucosidase-producing bacteria and fungi identified in this study may represent potential indicators of composting in cellulose degradation.
Publication
Journal: Life Sciences
December/18/1994
Abstract
The growth hormone (GH) releasing effect of GH-releasing hormone (GHRH) and galanin, a 29-amino acid peptide widely distributed in mammalian CNS, was investigated in cultured rat pituitary tumor cells (GH1) as compared to normal rat somatotrophs. GHRH stimulated dose-dependently GH secretion in normal somatotrophs but did not affect GH secretion in GH1 cells. Galanin (1-10 microM) stimulated GH release in a concentration-dependent manner, but with lower potency as compared to GHRH, in normal rat pituitaries but was inhibitory in rat GH1 cells. The results of this study indicate that while galanin has the ability to stimulate GH release from dispersed pituitary cells of normal rats it has potent direct inhibitory effects on GH release from tumor rat cells.
Publication
Journal: Oncology Research
August/22/1994
Abstract
Bromocriptine, a dopamine agonist, is now an accepted primary therapeutic agent for patients with prolactinomas and other pituitary adenomas. In this study, we demonstrated that bromocriptine inhibited the proliferation of rat somatotrophin-secreting pituitary adenoma (GH1) cells. In addition, the antitumor activity of bromocriptine was inhibited both by actinomycin D and cycloheximide, suggesting that it was dependent upon new RNA and protein synthesis. Interestingly, the results of DNA fragmentation assay and cell cycle analysis clearly demonstrated that bromocriptine induced apoptosis in GH1 cells.
Publication
Journal: Regulatory peptides
September/15/1997
Abstract
Previous studies demonstrated that GHRP-6 has modest GH-releasing activity in primary pituitary cell monolayer cultures. However, the effects of this peptide have always been tested on cells very sensitive to GHRH. We have previously reported that GHRH is unable to stimulate GH secretion in the GH1 rat tumor cell line. The aim of the study was to assess for the first time the effect on GH secretion of the GHRP-6 analog, hexarelin, in the GH1 cells; moreover, we investigated the potential involvement of GHRH in the effects of hexarelin in the GH1 rat cell line. The GHRP-6 analog hexarelin (0.01-1 microM) significantly stimulated GH release in both normal and GH1 rat cells. The greatest GH-releasing effect of hexarelin was observed with the 1 microM dose both in GH1 (155+/-25% vs. control wells) and in normal rat pituitary cells (185+/-23% vs. control wells). GHRH significantly stimulated GH secretion in normal rat somatotrophs (3-fold increase). In this latter cell model, GHRH and hexarelin were demonstrated to have additive stimulatory effects on GH secretion. Conversely, GHRH did not affect hexarelin-stimulated GH release in GH1 cells at any of the doses used. Finally, 8Br-cAMP significantly stimulated GH secretion in both normal rat and GH1 cells. These results provide in vitro evidence that non-GHRH-mediated pathways for GHRP action exist. Moreover, the observation that cells not sensitive to GHRH can be significantly stimulated by hexarelin strongly suggests that GHRPs and GHRH have two distinct sites and modes of action at the pituitary level.
Publication
Journal: Journal of cyclic nucleotide research
June/10/1979
Abstract
Somatostatin inhibits basal and chlorpromazine stimulated adenylyl cyclase activity in homogenates of GH1 rat pituitary tumor cells. The Dtryp8-Dcys14 analogue is more potent than tyrosyl somatostatin as an inhibitor of both basal and chlorpromazine-stimulated adenylyl cyclase. Somatostatin had no effect on sodium fluoride or quanylyl-imidodiphosphate-stimulated cyclase in GH1 cell homogenates or on basal, epinephrine or prostaglandin E1 stimulated cyclase activity in sonicated BHK fibroblasts. These results indicate a specific effect of somatostatin to inhibit pituitary adenylyl cyclase activity.
Publication
Journal: In vitro cellular & developmental biology : journal of the Tissue Culture Association
April/11/1989
Abstract
The growth of GH4C1, GH3, GH1, and GH3C15 rat pituitary tumor cell lines was studied in a serum-free medium (designated TRM-1) formulated with 1:1 (vol/vol) mixture of Ham's F12 nutrient mixture and Dulbecco's modified Eagle's medium (F12-DME) containing 15 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), 50 micrograms/ml gentamicin supplemented with 10 micrograms/ml bovine insulin, 10 micrograms/ml human transferrin (Tf), 10 ng/ml selenous acid, 10 nM 3,5,3'-triiodothyronine (T3), 50 microM ethanolamine (Etn), and 500 micrograms/ml bovine serum albumin. Of the lines evaluated, only the GH1 failed to grow in TRM-1. Passage of the GH4C1 and GH3 lines from serum-containing medium into TRM-1 caused an initial selection resulting in cells that grew progressively at higher rates and finally were maintained indefinitely in TRM-1. These populations showed a requirement for supraphysiologic concentrations of T3 (1.0 to 10 nM). After adaptation of the GH4C1 line in TRM-1 for greater than or equal to 20 generations, removal of components gave a less complex mixture containing 15 mM HEPES, 50 micrograms/ml gentamicin, 10 micrograms/ml Tf, 10 nM T3, and 50 microM Etn (designated TRM-2) that supported serial passage of the cells. Under these conditions, thyroid hormone dependence was lost progressively. When T3 was removed from TRM-2 adapted cells, a third population was selected that no longer required thyroid hormones and was only slightly stimulated by T3. These studies demonstrated that the combination of serum-containing and serum-free conditions can be used to select pituitary cell populations that a) required both serum-factor(s) and T3 for optimum growth, b) required supraphysiologic concentrations of T3 without serum proteins other than Tf and albumin, and c) were completely autonomous in that they proliferated in medium supplemented only with Tf and nutrients without necessity of other serum factor(s) or T3.
Publication
Journal: Molecular and Cellular Endocrinology
April/22/1992
Abstract
Previously, we have studied thyroid hormone-dependent growth of GH1 rat pituitary tumor cells in iron-restricted serum-free defined medium (Sirbasku, D.A., et al. (1991) Biochemistry 30, 295-304, 7466-7477). Proliferation was promoted by triiodothyronine (T3) and any of seven forms of horse serum-derived apotransferrin (apoTf). In this report, we have asked if apoTfs from other species also acted as thyromedins and if other metal ion chelators served this role. To address these issues, three thyromedins were isolated from human serum and identified as apoTf. Fe3+ depletion, and assay in low-Fe medium, gave ED50s of 1.4-1.7 nM. Fe3+ saturation abolished their activities in high-Fe medium. To ask if apoTf was the major thyromedin in human serum, hormone-depleted preparations were iron saturated and shown to no longer support T3-dependent GH1 cell growth. Next, commercially prepared human, rat, horse, dog, rabbit, guinea pig and mouse apoTfs were shown to be as active under iron-restricted conditions as those isolated from human serum. Bovine apoTf and colostrum lactoferrin were greater than 100-fold less active; human milk apo-lactoferrin and apo-ovotransferrins were inactive. Transferrins which displayed thyromedin activity blocked the binding of 125I-rat 2Fe.Tf to GH1 cell receptors while those without thyromedin activity were ineffective. Finally, the metal ion chelators EDTA, citrate and deferoxamine did not show thyromedin activity indicating that apoTfs uniquely were able to promote T3-dependent cell growth in defined culture.
Publication
Journal: Frontiers in Physiology
December/6/2018
Abstract
The Pacific white shrimp (Litopenaeus vannamei), one of the most widely cultured shrimp species in the world, often suffers from cold stress. To understand the molecular mechanism of cold tolerance in Pacific white shrimp, we conducted a proteomic analysis on two contrasting shrimp cultivars, namely, cold-tolerant Guihai2 (GH2) and cold-sensitive Guihai1 (GH1), under normal temperature (28°C), under cold stress (16°C), and during recovery to 28°C. In total, 3,349 proteins were identified, among which 2,736 proteins were quantified. Based on gene ontology annotations, differentially expressed proteins largely belonged to biological processes, cellular components, and molecular functions. KEGG pathway annotations indicated that the main changes were observed in the lysosome, ribosomes, and oxidative phosphorylation. Subcellular localization analysis showed a significant increase in proteins present in cytosol, extracellular regions, and mitochondria. Combining enrichment-based clustering analysis and qRT-PCR analysis, we found that glutathione S-transferase, zinc proteinase, m7GpppX diphosphatase, AP2 transcription complex, and zinc-finger transcription factors played a major role in the cold stress response in Pacific white shrimp. Moreover, structure proteins, including different types of lectin and DAPPUDRAFT, were indispensable for cold stress tolerance of the Pacific white shrimp. Results indicate the molecular mechanisms of the Pacific white shrimp in response to cold stress and provide new insight into breeding new cultivars with increased cold tolerance.
Publication
Journal: Brazilian Dental Journal
December/12/2016
Abstract
Connecting prostheses to the implant abutments has become a concern and achieving a satisfactory retention has been focused in cement-retention prostheses recently. Sandblasting is a method to make a roughened surface for providing more retention. The aim of this study was to compare effects of nano and micro airborne abrasive particles (ABAP) in roughening surface of implant abutments and further retention of cemented copings. Thirty Xive abutments and analogues (4.5 D GH1) were mounted vertically in self-cured acrylic blocks. Full metal Ni-Cr copings with a loop on the top were fabricated with appropriate marginal adaptation for each abutment. All samples were divided into 3 groups: first group (MPS) was sandblasted with 50 µm Al2O3 micro ABAP, second group (NSP) was sandblasted with 80 nm Al2O3 nano ABAP, and the third group (C) was assumed as control. The samples were cemented with provisional cement (Temp Bond) and tensile bond strength of cemented copings was evaluated by a universal testing machine after thermic cycling. The t test for independent samples was used for statistical analysis by SPSS software (version 15) at the significant level of 0.05. Final result showed significant difference among all groups (p<0.001) and MPS manifested the highest mean retention (207.88 ± 45.61 N) with significant difference among other groups (p<0.001). The control group showed the lowest bond strength as predicted (48.95 ± 10.44 N). Using nano or micro ABAP is an efficient way for increasing bond strengths significantly, but it seems that micro ABAP was more effective.
Publication
Journal: Endocrinology
May/1/2018
Abstract
Growth hormone (GH), an endocrine hormone, primarily secreted from the anterior pituitary, stimulates growth, cell reproduction, and regeneration and is a major regulator of postnatal growth. Humans have two GH genes that encode two versions of GH proteins: a pituitary version (GH-N/GH1) and a placental GH-variant (GH-V/GH2), which are expressed in the syncytiotrophoblast and extravillous trophoblast cells of the placenta. During pregnancy, GH-V replaces GH-N in the maternal circulation at mid-late gestation as the major circulating form of GH. This remarkable change in spatial and temporal GH secretion patterns is proposed to play a role in mediating maternal adaptations to pregnancy. GH-V is associated with fetal growth, and its circulating concentrations have been investigated across a range of pregnancy complications. However, progress in this area has been hindered by a lack of readily accessible and reliable assays for measurement of GH-V. This review will discuss the potential roles of GH-V in normal and pathological pregnancies and will touch on the assays used to quantify this hormone.
Publication
Journal: Environmental Toxicology and Chemistry
January/25/2019
Abstract
The San Francisco Bay delta (USA) is experiencing seasonally warmer waters attributable to climate change and receives rainstorm runoff containing pyrethroid pesticides. Chinook salmon (Oncorhynchus tshawytscha) inhabit the affected waterways from hatch through smoltification, and thus juvenile fish may experience both pyrethroid and warmer water exposures. The effects of higher temperatures and pesticide exposure on presmolt Chinook are unknown. To improve understanding of the potential interaction between temperature and pesticide exposure on salmonid development, juvenile alevin and fry were reared in 11, 16.4, and 19 °C freshwater for 11 d and 2 wk, respectively, and exposed to nominal concentrations of 0, 0.15, and 1.5 µg/L bifenthrin for the final 96 h of rearing. Estradiol-17β (E2), testosterone, triiodothyronine, and thyroxine levels were measured in whole-body homogenates using hormone-specific enzyme-linked immunosorbent assays. Brain gonadotropin-releasing hormone receptor (GnRH2), dopamine receptor 2A, and growth hormone 1 (GH1) mRNA levels were measured using quantitative PCR. Results showed significantly decreased survival and condition factors observed with increasing temperature in alevin. Alevin thyroid hormones increased significantly with temperature, but fry thyroid hormones trended toward a decrease at lower temperatures with increasing bifenthrin exposure. There were significant reductions in fry testosterone and E2 at 11 °C with increasing bifenthrin treatments and significant changes in GnRH2 and GH1 gene expression in both alevin and fry, indicating potential disruption of hormonal and signaling pathways. Environ Toxicol Chem 2019;38:852-861. © 2019 SETAC.
Publication
Journal: Experimental Eye Research
November/12/2018
Abstract
The human growth hormone (GH) locus is comprised by two GH (GH1 and GH2) genes and three chorionic somatomammotropin (CSH1, CSH2 and CSH-L) genes. While GH1 is expressed in the pituitary gland, the rest are expressed in the placenta. However, GH1 is also expressed in several extrapituitary tissues, including the eye. So to understand the role of this hormone in the eye we used the baboon (Papio hamadryas), that like humans has a multigenic GH locus; we set up to investigate the expression and regulation of GH locus in adult and fetal baboon ocular tissues. We searched in baboon ocular tissues the expression of GH1, GH2, CSH1/2, Pit1 (pituitary transcription factor 1), GHR (growth hormone receptor), GHRH (growth hormone releasing hormone), GHRHR (growth hormone releasing hormone receptor), SST (somatostatin), SSTR1 (somatostatin receptor 1), SSTR2 (somatostatin receptor 2), SSTR3 (somatostatin receptor 3), SSTR4 (somatostatin receptor 4), and SSTR5 (somatostatin receptor 5) mRNA transcripts and derived proteins, by qPCR and immunofluorescence assays, respectively. The transcripts found were characterized by cDNA cloning and sequencing, having found only the one belonging to GH1 gene, mainly in the retina/choroid tissues. Through immunofluorescence assays the presence of GH1 and GHR proteins was confirmed in several retinal cell layers. Among the possible neuroendocrine regulators that may control local GH1 expression are GHRH and SST, since their mRNAs and proteins were found mainly in the retina/choroid tissues, as well as their corresponding receptors (GHRH and SSTR1-SSTR5). None of the ocular tissues express Pit1, so gene expression of GH1 in baboon eye could be independent of Pit1. We conclude that to understand the regulation of GH in the human eye, the baboon offers a very good experimental model.
Publication
Journal: Hemoglobin
December/12/2016
Abstract
We review and report here the genotypes and phenotypes of 60 novel thalassemia and abnormal hemoglobin (Hb) mutations discovered following the adoption of routine DNA sequencing of both α- and β-globin genes for all UK hemoglobinopathy samples referred for molecular investigation. This screening strategy over the last 10 years has revealed a total of 11 new β chain variants, 15 α chain variants, 19 β-thalassemia (β-thal) mutations and 15 α(+)-thalassemia (α(+)-thal) mutations. The large number of new thalassemia alleles confirms the wide racial heterogeneity of mutations in the UK immigrant population. Eleven of the new variants ran with Hb A on high performance liquid chromatography (HPLC), demonstrating the value of routine sequencing of both α- and β-globin genes for all hemoglobinopathy investigations. The new β chain variants are: Hb Bury [β22(B4)Glu → Asp (HBB: c.69A>> T)], Hb Fulwood [β35(C1)Tyr → His (HBB: c.106T>> C)], Hb Little Venice [β42(CD1)Phe → Cys (HBB: c.128T>> G)], Hb Cork [β57(E1)Asn → Ser (HBB: c.173A>> G), Hb Basingstoke [β118(GH1)Phe → Ser (HBB: c.356T>> C)], Hb Howden [β20(B2)Val → Ala (HBB: c.62T>> C)], Hb Wilton [β41(C7)Phe → Leu (HBB: c.126C>> A)], Hb Belsize Park [β120(GH3)Lys → Asn (HBB: c.363A>> T)], Hb Hampstead Heath [β2(NA2)His → Gln;β26(B8)Glu → Lys (HBB: c.[6C>> G;79G>> A])], Hb Grantham [β85(F1)Phe → Cys (HBB: c.257T>> G)] and Hb Calgary [β64(E8)Gly → Val (HBB: c.194G>> T). The new α chain variants are: Hb Edinburgh [α70(E19)Val → Gly (HBA2: c.212T>> G)], Hb Walsgrave [α116(GH4)Glu → Val (HBA2: c.350A>> T)], Hb Wexham [α117(GH5) and 118(H1) insertion Ser (HBA1: c.354-355insTCA)], Hb Coombe Park [α127(H10)Lys → Glu (HBA2: c.382A>> G)], Hb Oxford [α17(A15)Val → Asp (HBA2: c.53T>> A)], Hb Bridlington [α32(B13)Met → Thr (HBA1: c.98T>> C), Hb Wolverhampton [α81(F2)Ser → Tyr (HBA2: c.9245C>> A)], Hb Little Waltham [α13(A11)Ala → Asp (HBA2: c.41C>> A)], Hb Derby [α61(E10)Lys → Arg (HBA1: c.185A>> G)], Hb Uttoxter [α74(EF3)Tyr → Asp (HBA2: c.223G>> T)], Hb Harehills [α124(H7)Ser → Cys (HBA1: c.374C>> G)], Hb Hekinan II [α27(B8)Glu → Asp (HBA1: c.84G>> T)], Hb Manitoba IV [α102(G9)Ser → Arg (HBA1: c.307A>> C), Hb Witham [α139(HC1)Lys → Arg (HBA2: c.419A>> G) and Hb Farnborough [α9(A7)Asn → Asp (HBA1: c.28A>> G). In addition, 10 more paralogous α-globin chain variants have been discovered. The novel β-thal alleles are: HBB: c.-138C>> G, HBB: c.-121C>> T, HBB: c.-80T>> G, HBB: c.18_19delTG, HBB: c.219_220insT, HBB: c.315 + 2_315 + 13delTGAGTCTATGGG, HBB: c.316-70C>> G, HBB: c.345_346insTGTGCTG, HBB: c.354delC, HBB: c.376-381delCCAGTG, HBB: c.393T>> A, HBB: c.394_395insA, HBB: c.375_376insA, HBB: c.*+95_*+107delTGGATTCTinsC, HBB: c.* + 111_*+112delAA, HBB: c.*+112A>> T, HBB: c.394C>> T, HBB: c.271delG and HBB: c.316-3C>> T. The novel α (+ )-thal alleles are: HBA1: c.95+1G>> C, HBA1: c.315C>> G [Hb Donnington, α104(G11)Cys → Trp], HBA1: c.327delC, HBA1: c.333_345del, HBA1: c.*+96G>> A, HBA2: c.2T>> G, HBA2: c.112delC, HBA2: c.143delA, HBA2: c.143_146delACCT, HBA2: c.156_157insG, HBA2: c.220_223delGTGG, HBA2: c.305T>> C [Hb Bishopstown, α101(G8)Leu → His], HBA2: c.169_170delAA, HBA2: c.1A>> T and HBA2: c.-3delA.
Publication
Journal: Plant Biotechnology Journal
July/10/2020
Abstract
High-temperature bioconversion of lignocellulose into fermentable sugars has drawn attention for efficient production of renewable chemicals and biofuels, because competing microbial activities are inhibited at elevated temperatures and thermostable cell wall degrading enzymes are superior to mesophilic enzymes. Here, we report on the development of a platform to produce four different thermostable cell wall degrading enzymes in the chloroplast of Chlamydomonas reinhardtii. The enzyme blend was composed by the cellobiohydrolase CBM3GH5 from C. saccharolyticus, the β-glucosidase celB from P. furiosus, the endoglucanase B and the endoxylanase XynA from T. neapolitana. In addition, transplastomic microalgae were engineered for expression of phosphite dehydrogenase D from Pseudomonas stutzeri, allowing for growth in non-axenic media by selective phosphite nutrition. The cellulolytic blend composed by the glycoside hydrolase (GH) domains GH1GH1 allowed the conversion of alkaline-treated lignocellulose into glucose with efficiencies ranging from 14% to 17% upon 48h of reaction and an enzyme loading of 0.05% (w/w). Hydrolysates from treated cellulosic materials with extracts of transgenic microalgae boosted both the biogas production by methanogenic bacteria and the mixotrophic growth of the oleaginous microalga Chlorella vulgaris. Notably, microalgal treatment suppressed the detrimental effect of inhibitory by-products released from the alkaline treatment of biomass, thus allowing for efficient assimilation of lignocellulose-derived sugars by C. vulgaris under mixotrophic growth.
Keywords: Chlamydomonas; Chlorella; biofuel; biogas; cell wall degrading enzymes; glycoside hydrolases; phosphite; plant cell wall; transplastomic microalgae.
Publication
Journal: Pituitary
September/6/2020
Abstract
Context: Regional variation in prevalence of genetic mutations in growth hormone deficiency (GHD) is known.
Aim: Study phenotype and prevalence of mutations in GH1, GHRHR, POU1F1, PROP1 genes in GHD cohort.
Methods: One hundred and two patients {Isolated GHD (IGHD): 79; combined pituitary hormone deficiency (CPHD): 23} with orthotopic posterior pituitary were included. Auxologic, hormonal and radiological details were studied. All four genes were analysed in IGHD patients. POU1F1 and PROP1 were studied in CPHD patients.
Results: Of 102, 19.6% were familial cases. Height SDS, mean (SD) was - 5.14 (1.63). Peak GH, median (range) was 0.47 ng/ml (0-6.59), 72.5% patients had anterior pituitary hypoplasia (APH). Twenty mutations (novel: 11) were found in 43.1% patients (n = 44, IGHD-36, CPHD-8). GHRHR mutations (n = 32, p.Glu72* = 24) were more common than GH1 mutations (n = 4) in IGHD cohort. POU1F1 mutations (n = 6) were more common than PROP1 mutations (n = 2) in CPHD cohort. With few exceptions, this prevalence pattern is contrary to most studies in world-literature. No patients with peak GH > 4 ng/ml had mutations, signifying it as negative predictor. While many parameters were significant on univariate analysis, only positive family history and lower median peak GH levels were significant predictors of mutations on multivariate analysis in IGHD patients.
Conclusion: At variance with world literature, we found reverse predominance of GHRHR over GH1 mutations, POU1F1 over PROP1 mutations and predominance of GHRHR p.Glu72* mutations thus re-affirming the regional diversity in GHD genetics. We report positive and negative predictors of mutations in GHD.
Keywords: Combined pituitary hormone deficiency (CPHD); GH1; GHRHR; Isolated growth hormone deficiency (IGHD); POU1FI; PROP1; Regional diversity; Short stature.
Publication
Journal: Hormone and Metabolic Research
April/25/2019
Abstract
The objective of the study is the functional characterization of a novel POU1F1 c.605delC mutation in combined pituitary hormone deficiency (CPHD) and to report the clinical and genetic details of 160 growth hormone deficiency patients. Screening of GH1, GHRHR, POU1F1, PROP1, and HESX1 genes by Sanger sequencing was carried out in 160 trios and 100 controls followed by characterization of the POU1F1 c.605delC mutation by expression studies including site directed mutagenesis, co-transfection, protein degradation, and luciferase assays to compare the wild type and mutant POU1F1. In vitro studies showed that the POU1F1 c.605delC mutation codes for a truncated protein with reduced transactivation capacity on its downstream effectors, viz., growth hormone (GH) and prolactin (PRL) causing severe CPHD. Experiments using different protease inhibitors reveal rescue of the protein upon blockage of the lysosomal pathway that might be useful in novel drug designing using targeted approach thereby maintaining the milieu and preventing/delaying the disease. The study provides an insight into the disease causing mechanism of POU1F1 c.605delC mutation identified in a CPHD child with severe short stature and failure to thrive. It also shows mutation effect on the expression, function and turnover of protein and highlights mechanistic details by which these potent regulators may operate.
Publication
Journal: Molecules
April/13/2019
Abstract
There has been an explosion of probiotic incorporated based product. However, many reports indicated that most of the probiotics have failed to survive in high quantity, which has limited their effectiveness in most functional foods. Thus, to overcome this problem, microencapsulation is considered to be a promising process. In this study, Lactococcus lactis Gh1 was encapsulated via spray-drying with gum Arabic together with Synsepalum dulcificum or commonly known as miracle fruit. It was observed that after spray-drying, high viability (~10⁸ CFU/mL) powders containing L. lactis in combination with S. dulcificum were developed, which was then formulated into yogurt. The tolerance of encapsulated bacterial cells in simulated gastric juice at pH 1.5 was tested in an in-vitro model and the result showed that after 2 h, cell viability remained high at 1.11 × 10⁶ CFU/mL. Incubation of encapsulated cells in the presence of 0.6% (w/v) bile salts showed it was able to survive (~10⁴ CFU/mL) after 2 h. Microencapsulated L. lactis retained a higher viability, at ~10⁷ CFU/mL, when incorporated into yogurt compared to non-microencapsulated cells ~10⁵ CFU/mL. The fortification of microencapsulated and non-microencapsulated L. lactis in yogurts influenced the viable cell counts of yogurt starter cultures, Lactobacillus delbrueckii subs. bulgaricus and Streptococcus thermophilus.
Publication
Journal: Endocrine
April/27/2020
Abstract
Short stature in children is a significant medical problem which, without proper diagnosis and treatment, can lead to long-term consequences for physical and psychological health in adult life. Since human height is a polygenic and highly heritable trait, numerous variants in the genes involved in growth-including the growth hormone (GH1) gene-have been identified as causes of short stature.In this study, we performed for the first time molecular analysis of the GH1 gene in a cohort (n = 186) of Polish children and adolescents with short stature, suffering from growth hormone deficiency (GHD) or idiopathic short stature (ISS), and a control cohort (n = 178).Thirteen SNP variants were identified, including four missense variants, six in 5'UTR, and three in introns. The frequency of minor missense variants was low (<0.02) and similar in the compared cohorts. However, two of these variants, Ala39Val (rs151263636) and Arg42Leu (rs371953554), were found (heterozygote status) in only two GHD patients. These substitutions, according to databases, can potentially be deleterious.Mutations of GH1 causing short stature are very rare in the Polish population, but two potentially causative variants need further studies in a larger cohort of GHD patients.
Publication
Journal: Essays in Biochemistry
June/18/2017
Abstract
Malarial infection continues to impart devastating health problems in the developing world. Treatment of malaria has involved chemotherapy since 168 BC, with the most prevalent and successful forms using plant alkaloids. Perhaps the greatest treatment success against malaria was by chloroquine, a synthetic derivative of the quinines found in the Cinchona tree bark. Chloroquine is able to kill parasites by interfering with haem metabolism in the parasite's digestive vacuole. The widespread use of chloroquine predictably resulted in the development of drug-resistant malaria and the most highly implicated resistance mediators are the transporter proteins P-glycoprotein (P-gp) homologue 1 (P-gh1) and Plasmodium falciparum chloroquine-resistance transporter (PfCRT), which reside on the parasite's digestive vacuole. The presence of PfCRT and P-gh1 on the vacuole membrane is analogous to the two-headed fictional creature known as the "Pushmi-Pullyu". P-gh1 (Pushmi) increases influx of chloroquine into the vacuole, while PfCRT (Pullmi) causes efflux of chloroquine from the vacuole. This review describes how drug-resistant malarial parasites co-ordinate chloroquine distribution through adaptive mutations to promote their survival in the presence of this cytotoxic drug.
Publication
Journal: Food Chemistry
July/25/2020
Abstract
β-Glucosidases play an important role in food industry. Oenococcus oeni are typical lactic acid bacteria that initiate malolactic fermentation of wines. 35 β-glucosidases from O. oeni were selected and their conserved domains and evolutionary relationships were further explored in this study. The homology analysis results indicated that 35 β-glucosidases were basically derived from GH1 and GH3 family. A novel β-glucosidase was successfully expressed and characterized. The recombinant protein, referred to as BGL0224, consisted of a total 480 amino acids with an apparent molecular weight of 55.15 kDa and was classified as GH1 family. It achieved the highest activity at pH 5.0 and 50 °C. The activity and stability were significantly increased when 12% ethanol was supplemented to the enzyme. Using p-NPG as substrate, the Km, Vmax and Kcat of BGL0224 were 0.34 mM, 382.81 U/mg and 351.88 s-1, respectively. In all, BGL0224 has good application prospects in food industry.
Keywords: Biochemistry; Evolution; Heterologous expression; Oenococcus oeni; β-Glucosidase.
Publication
Journal: Frontiers in Plant Science
August/15/2017
Abstract
Glycoside hydrolases Family 1 (GH1) comprises enzymes that can hydrolyze β-O-glycosidic bond from a carbohydrate moiety. The plant GH1 hydrolases participate in a number of developmental processes and stress responses, including cell wall modification, plant hormone activation or deactivation and herbivore resistance. A large number of members has been observed in this family, suggesting their potential redundant functions in various biological processes. In this study, we have used 304 sequences of plant GH1 hydrolases to study the evolution of this gene family in plant lineage. Gene duplication was found to be a common phenomenon in this gene family. Although many members of GH1 hydrolases showed a high degree of similarity in Arabidopsis and rice, they showed substantial tissue specificity and differential responses to various stress treatments. This differential regulation implies each enzyme may play a distinct role in plants. Furthermore, some of salt-responsive Arabidopsis GH1 hydrolases were selected to test their genetic involvement in salt responses. The knockout mutants of AtBGLU1 and AtBGLU19 were observed to be less-sensitive during NaCl treatment in comparison to the wild type seedlings, indicating their participation in salt stress response. In summary, Arabidopsis and rice GH1 glycoside hydrolases showed distinct features in their evolutionary path, transcriptional regulation and genetic functions.
Publication
Journal: Food Chemistry
February/24/2016
Abstract
Genetic transformation of fish is mainly oriented towards the improvement of growth for the benefit of the aquaculture. Actually, Atlantic salmon (Salmo salar) is the species most transformed to achieve growth rates quite large compared to the wild. To anticipate the presence of contaminations with GM salmon in fish markets and the lack of labeling regulations with a mandatory threshold, the proper methods are needed to test the authenticity of the ingredients. A quantitative real-time polymerase chain reaction (QRT-PCR) method was used in this study. Ct values were obtained and validated using 15 processed food containing salmon. The relative and absolute limits of detection were 0.01% and 0.01 ng/μl of genomic DNA, respectively. Results demonstrate that the developed QRT-PCR method is suitable specifically for identification of S. salar in food ingredients based on the salmon growth hormone gene 1 (GH1). The processes used to develop the specific salmon reference gene case study are intended to serve as a model for performing quantification of Aquadvantage® GM salmon on future genetically modified (GM) fish to be commercialized.
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