bluuebunny/crossref_metadata_2025 huggingface dataset:
The study of hybridization processes within genus Sparganium L. Subgenus Xanthosparganium holmb. Based on data of next generation sequencing (NGS)
Authors: Belyakov Evgeniy A. , Machs Eduard M. , Mikhailova Yulia V. , Rodionov Aleksandr V.
Published: January 2020

The study represents the results of research of intragenic polymorphism in transcribed spacer ITS1 of the 35S rRNA genes in representatives of subgenus Xanthosparganium genus Sparganium which were obtained by means of locus-specific next generation sequencing on the platform Illumina MiSeq. It was shown that ribotype variations in studied samples generally correspond to the division of this genus into three sections Erecta (subgenus Sparganium), Natantia and Minima (subgenus Xanthosparganium). High level of intragenic polymorphism was revealed in S. hyperboreum, with ribotypes distributed among several groups. Genome of this species includes ribotypes which are typical for other species in subgenus Xanthosparganium. For two investigated S. glomeratum samples, there were no ribotypes similar to such ribotypes in other species of Natantia section. S. glomeratum has got ribotypes identical with S. hyperboreum of Minima section. This feature may be the evidence of ancient intersectional hybridization of these two species. Characteristics of rDNA in S. glomeratum are in favor of putting this species into Minima section. It was suggested that speciation processes within the genus could be based not only on hybridization but also went on in allopatric way. The fist statement is supported by the presence of similar and identical ribotypes in S. emersum, S. longifolium, S. gramineum and S. hyperboreum, the second as it was mentioned by other researchers, is due to close relationship between North American and Eurasian taxa.
Ecological genetics of Adalia beetles: variability and symbiotic bacteria in european populations of the ten-spot ladybird beetle Adalia decempunctata
Authors: Shaikevich Elena V. , Zakharov Ilya A. , Honek Alois
Published: January 2020

Background. Adalia decempunctata L. (Coleoptera: Coccinellidae) ten-spot ladybird beetle, widespread morphologically variable Palearctic species.
Materials and methods. DNA polymorphism and infection with Wolbachia, Spiroplasma and Rickettsia symbiotic bacteria were investigated.
Results. Eight different haplotypes of the mitochondrial COI gene, seven of which were previously unknown, were found in 92 A. decempunctata individuals from nine European collection places: Prague, Rome, Florence, Hamburg, Paris, Stockholm, Moscow, Feodosia and Yalta. A. decempunctata is less variable in mtDNA compared to A. bipunctata. Symbiotic bacteria Wolbachia and Spiroplasma were not detected. Only Rickettsia infestation was found in A. decempunctata specimens, gathered in Stockholm and Feodosia. Rickettsia from A. decempunctata from Feodosia and Stockholm differ by 0.5% in gltA gene. Rickettsia from A. decempunctata from Feodosia is clustered with Rickettsia from A. bipunctata and Coccinella sp. based on the analysis of the gltA gene.
Conclusion: Three of the eight mtDNA haplotypes are present in the A. decempunctata gene pool from geographically distant habitats. A small amount of nucleotide substitutions between Rickettsia from A. decempunctata and A. bipunctata suggests a single origin of the symbiont in the ladybirds of the genus Adalia, the results do not exclude subsequent horizontal transfers between individuals of both species.
The analysis of the polyamine oxidase genes in the methylotrophic yeast Komagataella phaffii
Authors: Ivanova Alina V. , Sidorin Anton V. , Sambuk Elena V. , Rumyantsev Andrei M.
Published: January 2020

Polyamines are present in all living cells and regulate a wide range of biological processes. In Saccharomyces cerevisiae the polyamine oxidase Fms1p converts spermine to spermidine and 3-aminopropionaldehyde, which is necessary for the synthesis of pantothenic acid and hypusination. This paper shows that S. cerevisiae FMS1 gene orthologs are present in all major representatives of the Saccharomycotina subdivision, but their copy numbers are different. In the Komagataella phaffii (Pichia pastoris) yeast, two polyamine oxidase genes (KpFMS1 and KpFMS2) were identified, and the regulation of their promoters activity was studied.
Organization of the endoplasmic reticulum in cells of effective and ineffective pea nodules (Pisum sativum L.)
Authors: Tsyganova Anna V. , Tsyganov Viktor E.
Published: January 2020

Background. The endoplasmic reticulum (ER) is the largest membrane-bound organelle, which plays an important role in the functioning of a plant cell and participates in its differentiation.
Materials and methods. Using the methods of transmission electron microscopy, the morphological features and dynamics of structural changes in the ER in symbiotic nodules of pea (Pisum sativum L.) wild-type and mutants blocked at different stages of nodule development were studied.
Results. ER developed from a network of individual tubules in meristematic cells, to a developed network of cisterns around the nucleus and plasmalemma, and a network of granular and smooth tubules accompanying infection structures in colonized and infected cells and symbiosomes in infected cells.
Conclusions. A correlation was found between the level of development of the ER network and the degree of bacteroid differentiation.
Micronuclei in blood lumphocytes of existing and former coal miners: evaluation of the effect of anthracosilicosis
Authors: Druzhinin Vladimir G. , Apalko Svetlana V. , Baranova Elizaveta D. , Volobaev Valentin P. , Drobchik Tatiana Yu. , Larionov Aleksey V. , Hill Elena G. , Chasovskikh Elena V.
Published: January 2020

Background. The purpose of this study was to investigate the genotoxic risk in anthracosilicosis patients and in those with occupational exposure to coal dust.
Materials and methods. We studied micronuclei (MN) and other cytogenetic lesions in blood lymphocytes in three groups of men comparable in age: 74 coal miners suffering from anthracosilicosis (AS), 41 healthy miners, and 70 control donors.
Results. A significant increase in the frequency of MN was revealed with a simultaneous decrease in proliferative activity in samples of healthy and sick miners compared with the control. The level of MN in the lymphocytes of patients with AS significantly exceeded the corresponding indicator in the sample of healthy miners (1.22 0.05% versus 1.03 0.07%; p 0.01). The age of the subjects and the status of smoking did not have a significant effect on the frequency of cytogenetic parameters.
Conclusion. AS in miners makes an additional contribution to the formation of DNA damage in lymphocytes. This contribution is probably due to oxidative stress accompanying inflammatory processes in pulmonary fibrosis. The results of the study also indicate the absence of differences in the frequency of MN when comparing subgroups of current and former miners. This means that the genotoxic effects in the lymphocytes of miners are able to persist for a long time after the termination of exposure by adverse factors in coal mining.
The polygenic nature of rheumatoid arthritis
Authors: Kuzhir Tat'yana D.
Published: January 2020

Current advances in the genetic basis of rheumatoid arthritis (RA) were summarized in the review. Influence of gene polymorphisms involved in different cellular processes including cytokine-mediated signal transduction, immune and inflammatory responses to exogenous stimuli was discussed. The principal role of the major histocompatibility complex (MHC) and a shared epitope (SE), as well as contribution of non-HLA genes to susceptibility to RA was considered in terms of patients ethnicity and the serological status for the disease. The GWAS results for revealing candidate genes closely associated with RA risk were systematized as well as some aspects of epigenetics were mentioned. The findings indicated the polygenic nature of this complex disease. This problem was considered taking into account the recent results of mapping traits (eQTLs) with global gene expression. The novel omnigenic conception of heritability of complex traits/diseases was reported.
Effects of the intestinal microbiota on epigenetic mechanisms involved in the development of post-stress neuro-inflammation
Authors: Shalaginova Irina G. , Matskova Liudmila V. , Gunitseva Natalia M. , Vakoliuk Irina A.
Published: January 2020

A number of alleles of polymorphic genes, dysfunctions of the hypothalamic-pituitary-adrenal axis, neurotransmitter disorders, and manifestations of immune dysregulation are associated with vulnerability to stress. Post-stress states of humans and animals are accompanied by signs of neuroinflammation, the causes and mechanisms of which remain to be elucidated. The article discusses epigenetic mechanisms by which the intestinal microbiota might participate in the initiation and maintenance of post-stress inflammation.
An Analysis of Small Retailers' Relationships with Tobacco Companies in 4 US Cities
Authors: D'Angelo Heather , Ayala Guadalupe X. , Gittelsohn Joel , Laska Melissa N. , Sindberg Lesley Schmidt , Horton Lucy , Kharmats Anna Y. , Ribisl Kurt M.
Published: January 2020

Objective: In this study, we examined small food store retailers' perspectives on tobacco company agreements specifying tobacco product display and promotion. Methods: We interviewed owners/managers of small food stores (N = 63) in lower-income neighborhoods in 4 US cities
using open-and closed-ended questions between October 2013 and July 2014. We coded qualitative interview data and calculated descriptive statistics. Results: Most retailers had a formal contract with a tobacco company (87%). Retailers perceived that tobacco products generated low profits,
but were important to attract customers. Nearly 95% with contracts reported receiving an incentive, including marketing materials (86.8%), displays (79%), and free/discounted products (50.9%). Contract requirements included placing branded displays and marketing materials in prime locations
and setting cigarette prices. Retailers in urban, African-American neighborhoods felt pressure to maintain menthol cigarette contracts to stay in business. Conclusion: Contracts with tobacco companies were common among the small food stores in this study, and retailers felt they needed
the contracts to keep prices competitive. Given the reliance of retailers on tobacco industry contracts, states and localities may need to adopt measures to counter their effects, especially the financial incentives that lead to lower cigarette prices and more prominent displays of promotions
and marketing materials.
Awareness and Perceived Risk of Heated Tobacco Products
Authors: Fung Michael D.T. , Diemert Lori M. , Zhang Bo , O'Connor Shawn , Schwartz Robert
Published: January 2020

Objectives: Heated tobacco products (such as IQOS) and e-cigarettes have been introduced and advertised in a variety of ways despite inconclusive evidence regarding their safety and benefit for smoking cessation. In this study, we examine the awareness, use, and perceived risk
of these products among recent smokers. Methods: In 2017, we conducted an online survey of 727 current and recent smokers in Ontario. We asked participants about their awareness, use, and perceived risk of heated tobacco products and e-cigarettes. Results: Among respondents,
10% were aware of heated tobacco products, and 3% had ever used them. Compared to non-ecigarette users, e-cigarette users were more likely to agree with statements that heated tobacco is less harmful than regular cigarettes, e-cigarette use is less harmful than regular cigarettes, and both
products can help smokers stop smoking regular cigarettes. Conclusions: Respondents who used e-cigarettes were more likely to have positive perceptions about heated tobacco and may be more susceptible to the marketing of these products. It is important to monitor the use of multiple
nicotine products to inform policies and programming for these products.
Social Response to the FDA Authorization of Heated Tobacco Products (HTPs)
Authors: Jun Jungmi
Published: January 2020

Objectives: The US Food and Drug Administration (FDA) approved sales of heated tobacco products (HTPs) on April 30, 2019. In this paper, I provide a preliminary analysis of social media conversations regarding HTPs and the FDA authorization in the first 60 days. Methods:
I examined 574 tweets regarding HTPs to assess tweet characteristics and semantic networks of HTPs. Results: Tweets were more likely to be neutral or anti-HTPs than pro-HTPs regardless of the author type (except for tobacco industry) or genre of the post. There was a small gap (6.4%)
between the proportion of pro-HTPs and anti-HTPs among personal tweets. The proportion of pro-HTPs was larger in tweets posted by men (vs women and no sex specified) and from rural areas (vs urban). Nearly one-third of the sample mentioned cigarettes or e-cigarettes, even though the size of
posts making claims on inferiority/superiority of HTPs was small. Conclusions: Social media conversations on risks of HTPs as well as surveillance on young consumer target marketing is occurring, and it will be important to assess the impact of tobacco companies' launch of HTP sales
in the US to assess public perceptions on HTPs. Continuing surveillance of HTP marketing and risk perceptions will inform tobacco regulations.
JUUL and Combusted Cigarettes Comparably Impair Endothelial Function
Authors: Rao Poonam , Liu Jiangtao , Springer Matthew L.
Published: January 2020

Objectives: JUUL and earlier generation electronic cigarettes (e-cigs) are promoted as being less hazardous than cigarettes. JUUL Labs, in particular, claims that switching from smoking to vaping has beneficial impacts; however, the health effects of such products are not well
understood. We investigated whether exposure to JUUL and previous generation e-cig aerosol impairs endothelial function comparably to cigarette smoke. Methods: We exposed rats to aerosol from Virginia Tobacco flavor JUUL, an e-cig tank system using unflavored free-base nicotine e-liquid,
Marlboro Red combustible tobacco cigarettes, or clean air for 10 cycles of 2 second inhalation over 5 minutes. We measured endothelial function pre- and post-exposure. Blood was collected 20 minutes post-exposure for serum nicotine analysis. Results: Aerosol/smoke from JUUL, previous
generation e-cigs, and cigarettes all impaired endothelial function. The extent of impairment ranged from 34% to 58%, although the differences between groups were not statistically significant. Nicotine was highest in serum from the JUUL group; for the other e-cig and cigarette groups, nicotine
levels were lower and comparable to each other.Conclusions: Aerosol from JUUL and previous generation e-cigs impairs endothelial function in rats, comparable to impairment by cigarette smoke.
Erratum: In the paper by Rao et al. (Volume 6, Number 1, January 2020, pp. 30-37(8), DOI: https://doi.org/10.18001/TRS.6.1.4), the graph in Figure 4 erroneously listed Y axis units as ng/dl instead of the correct ng/ml. The pdf for download has been corrected. The authors regret the error.
College Students' Exposure and Engagement with Tobacco-related Social Media
Authors: Clendennen Stephanie L. , Vandewater Elizabeth A. , Loukas Alexandra , Perry Cheryl L. , Wilkinson Anna V.
Published: January 2020

Objectives: In this study, we examine the prevalence and demographic, social, and behavioral characteristics associated with college students' exposure to and engagement with tobaccorelated social media, in a diverse sample from the Marketing and Promotions Across Colleges in
Texas Study (N = 4384). Methods: We used multiple logistic regression to examine cross-sectional associations between characteristics and exposure and engagement. Results: Overall, 30% of students reported past 30-day exposure to tobacco advertising on social media. Exposure
was greatest for e-cigarette advertisements on Facebook. A total of 23% reported engagement. Anti-engagement activities, like posting links to anti-tobacco messaging, were more prevalent than pro-engagement. Racial/ethnic minorities, 2-year college students, dual/poly-users, higher social
media users, students with friends who use tobacco, and students with higher depressive symptoms were significantly more likely to report exposure. Racial/ethnic minorities, sexual/gender minorities, 2-year college students, dual/poly-users, higher social media users, and students with higher
depressive symptoms were more likely to report pro-engagement. Sexual/gender minorities, non-users and dual/poly-users (vs single-product users), higher social media users, students with friends who use tobacco, and students with higher depressive symptoms were more likely to report anti-engagement.
Females were more likely to report hookah advertising exposure and anti-tobacco engagement. Conclusions: We discuss the regulatory and practical implications.
Electronic Nicotine Delivery Systems: Comparative Topography Assessments
Authors: Koszowski Bartosz , Salazar Esther , Thanner Meridith Hill , Pickworth Wallace B. , Paredes Antonio , Schroeder Megan J.
Published: January 2020

Objectives: Due to rapidly emerging electronic nicotine delivery system (ENDS) technologies, increasing use in the US, and the unclear impact on users' health, investigating behavior associated with ad libitum ENDS use is an important research topic. ENDS use behavior
is typically assessed either by direct observation or through smoking topography recording units; however, systematic comparisons between these methods are lacking. Therefore, we sought to compare 2 common methods to quantify ENDS topography. Methods: Current ENDS users (N = 18) used
their own brand ENDS ad libitum in a clinical laboratory. We compared smoking topographybased recording units (desktop Clinical Research Support System; CReSS) and observational video-recordings with frame-by-frame (FxF) analysis methods to quantify ENDS topography. Results:
Although CReSS analyses tended to estimate higher puff count and shorter average puff duration than FxF analyses, estimates of total puff duration were not different. Furthermore, both topography analysis methods showed significant associations with estimated nicotine intake. Conclusions:
Neither the CReSS nor the FxF method is suited perfectly for analyzing ENDS topography. However, because FxF analysis is time-consuming and cumbersome, smoking topography-based recording unit methods may offer a more practical approach to measure ENDS topography; however, researchers must
consider its limitations.
E-cigarette Product Preferences among Adult Smokers: A Discrete Choice Experiment
Authors: Shang Ce , Weaver Scott R. , White Justin S. , Huang Jidong , Nonnemaker James , Cheng Kai-Wen , Chaloupka Frank J.
Published: January 2020

Objectives: In this study, we used a discrete choice experiment (DCE) conducted August-October 2017 to examine electronic nicotine delivery systems (ENDS) product preferences in a national sample of adult smokers (N = 1154) who were also using ENDS or had not ruled out future
use. Methods: The DCE evaluated 5 ENDS attributes: relative harm; effectiveness for helping smokers quit; nicotine strength; flavor; and price. We asked participants to choose among their own cigarettes, 2 ENDS products whose attributes varied across tasks, or none. We analyzed ENDS
preferences using multinomial, nested, and mixed logit regressions. Results: Smokers preferred ENDS that are less harmful than cigarettes, are effective in helping smokers quit, are lower priced, and are not menthol-flavored. The marginal willingness to pay for an ENDS product was $8.40
when less harmful than cigarettes, $4.13 when of unknown effectiveness in helping quitting ($13.90 when effective), and $3.37 when ENDS are not menthol-flavored. Furthermore, the overall flavor preference is driven by tobacco smokers, not by menthol cigarette smokers who
do prefer menthol-flavored ENDS. Conclusions: Policies that affect perceptions of ENDS effectiveness in promoting cessation and their relative harm may alter smokers' ENDS preferences. Regulating flavors and price also may influence adult smokers' ENDS preference.
Intramolecular electron transfer between tryptophan radical and tyrosine in oligoproline-bridged model peptides and hen egg-white lysozyme.
Authors: Wierzchowski K L
Published: January 2020

Long range electron transfer (LRET) across protein matrix underlies all one-electron cellular redox reactions. Elucidation of molecular electron transfer pathways and parametrization of their relative efficiency is one of the most challenging problems in the studies on LRET in proteins. In this paper results of pulse radiolysis investigations on kinetics of LRET accompanying intramolecular radical transformation Trp. --> TyrO. in model peptides built of tryptophan and tyrosine bridged by an oligoproline fragment are reviewed, along with an interpretation of the observed distance dependence of the rate of LRET in terms of conformational properties of the peptides, and partitioning of LRET between electron transfer pathways through space and through peptide backbone. This review on model peptide systems is supplemented with recapitulation of similar studies on the same intramolecular transformation in hen egg-white lysozyme, which allowed to identify Trp./Tyr redox pairs and associated electron transfer pathways involved in LRET in this protein.
Molten globule as an intermediate on the human prostatic phosphatase folding pathway.
Authors: Kuciel R , Mazurkiewicz A
Published: January 2020

Human prostatic acid phosphatase (hPAP, EC.3.1.3.2), a secretory homodimeric protein was denatured in 6 M urea, pH 2.5, and refolded by dilution at pH 7.2 with recovery of the enzymatic activity and dimeric structure. Circular dichroism, intrinsic fluorescence and chromatographic analysis of renaturating protein suggested that the kinetic intermediate of the hPAP folding is a monomer which displays a molten globule state (R. Kuciel, A. Mazurkiewicz & W.S. Ostrowski, 1996, Int. J. Biol. Macromol. 18, 167-175). To confirm these data experiments were performed to estimate the interaction of the renaturating protein with dyes and amphipathic lipid structures. Increased binding of the hydrophobic probe 1-anilinonaphthalene-8-sulfonate and Congo Red to the refolding enzyme supported the existence of molten globule state with the relaxed beta-structure in the renaturating protein. Presence of liposomes, included in the renaturation mixture as a model of acid phospholipid, resulted in perturbations of the human PAP refolding process. Some folding intermediates were bound to phosphatidylserine liposomes or, alternatively, water soluble, inactive aggregates were formed.
Covalent modification and site-directed mutagenesis of an active site tryptophan of human prostatic acid phosphatase.
Authors: Zhang Z , Ostanin K , Van Etten R L
Published: January 2020

Because tryptophans are found as part of the phosphate binding sites in a number of proteins, human prostatic acid phosphatase (hPAP) was examined for the presence and the role of essential tryptophan residues. The pH dependence of the intrinsic fluorescence of hPAP resembled the kinetic pH dependence. Chemical modification by N-bromosuccinimide (NBS) resulted in an inactivation of the enzyme and produced a characteristic reduction of the protein absorbance at 280 nm. Two tryptophans per subunit were modified, and this was accompanied by an apparently complete loss of enzymatic activity. In the presence of the competitive inhibitor L-(+)-tartrate, the loss of enzyme activity was significantly reduced as compared to the rate of tryptophan modification. After labeling the protein with 2,4-dinitrophenylsulfenyl chloride (DNPS-Cl), two tryptic peptides containing DNPS-labeled tryptophans were isolated and the sequences were identified by amino acid sequence analysis and mass spectroscopy. One peptide corresponded to residues 172-176, and included Trp174. The other corresponded to the C-terminal sequence, including Trp336. It was concluded that Trp174 was at the active site of the human enzyme because it was protected by the competitive inhibitor tartrate in the DNPS-Cl modification studies. This is also consistent with the location of a homologous residue in the structure of the rat enzyme. Using site-directed mutagenesis, Trp174 was replaced by Phe or Leu. Both mutants showed altered kinetic properties, including lower Km values with several aromatic substrates, and also exhibited reduced stability towards urea denaturation.
The role of lysine-256 in the structure and function of sheep liver recombinant serine hydroxymethyltransferase.
Authors: Talwar R , Jagath J R , Datta A , Prakash V , Savithri H S , Rao N A
Published: January 2020

The active site lysine residue, K256, involved in Schiff's base linkage with pyridoxal-5'-phosphate (PLP) in sheep liver recombinant serine hydroxymethyltransferase (rSHMT) was changed to glutamine or arginine by site-directed mutagenesis. The purified K256Q and K256R SHMTs had less than 0.1% of catalytic activity with serine and H4folate as substrates compared to rSHMT. The mutant enzymes also failed to exhibit the characteristic visible absorbance spectrum (lambda(max) 425 nm) and did not produce the quinonoid intermediate (lambda(max) 495 nm) upon the addition of glycine and H4folate. The mutant enzymes were unable to catalyze aldol cleavage of beta-phenylserine and transamination of D-alanine. These results suggested that the mutation of the lysine had resulted in the inability of the enzyme to bind to the cofactor. Therefore, the K256Q SHMT was isolated as a dimer and the K256R SHMT as a mixture of dimers and tetramers which were converted to dimers slowly. On the other hand, rSHMT was stable as a tetramer for several months, further confirming the role of PLP in maintenance of oligomeric structure. The mutant enzymes also failed to exhibit the increased thermal stability upon the addition of serine, normally observed with rSHMT. The enhanced thermal stability has been attributed to a change in conformation of the enzyme from open to closed form leading to reaction specificity. The mutant enzymes were unable to undergo this conformational change probably because of the absence of bound cofactor.
Primary structure of porcine spleen ribonuclease: sequence homology.
Authors: Kusano A , Iwama M , Sanda A , Suwa K , Nakaizumi E , Nakatani Y , Ohkawa H , Ohgi K , Irie M
Published: January 2020

The primary structure of porcine spleen RNase (RNase Psp1) was investigated as a mean of assessing the structure-function relationship of base non-specific ribonucleases of animal origin. N-terminal analysis of RNase Psp1 yielded three N-terminal sequences. These peptides were separated by gel-filtration on Superdex 75HR, after reduction and S-carboxymethylation of RNase Psp1. Determination of the amino-acid sequence of these peptides indicated that the RNase Psp1 preparation consisted of three peptides having 20 (RCM RNase Psp1 pep1), 15 (RCM RNase Psp1 pep2), and 164 (RCM RNase Psp1 pro) amino-acid residues, respectively. It possessed two unique segments containing most of the active site amino-acid residues of the RNases of the RNase T2 family. The alignment of these three peptides in RNase Psp1 was determined by comparison with the other enzymes in the RNase T2 family. The overall results showed that RCM RNase Psp1 pep1 and RCM RNase Psp1 pep2 are derived from the N-terminal and C-terminal regions of RNase Psp1, respectively, probably by processing by some protease. The molecular mass of the protein moiety of RNase Psp1 was 23235 Da.
Female hormones act as natural antioxidants--a survey of our research.
Authors: Yagi K
Published: January 2020

The increase in the lipid peroxide level in the serum and liver of female mice after bilateral ovariectomy evidenced antioxidant activities of female hormones. This increase was abolished upon administration of female hormones. Similar increase in the level of lipid peroxide was observed in the serum of women who had undergone bilateral ovariectomy. Injection of 2-hydroxyestradiol suppressed the increase in the lipid peroxide level in the liver of rats receiving whole-body gamma-ray irradiation. Considering that the mechanism of coronary atherosclerosis is ascribed at least in part to the increased level of lipid peroxides, estrogen therapy could be applied to women who had undergone bilateral ovariectomy prior to menopause or to normal women after menopause. 2-Hydroxyestradiol might be applied also to men.
Tumor-specific pyruvate kinase isoenzyme M2 involved in biochemical strategy of energy generation in neoplastic cells.
Authors: Gumińska M , Ignacak J , Kedryna T , Stachurska M B
Published: January 2020

The differences in properties of pyruvate kinase (EC 2.1.7.40) from normal tissues and animal or human tumors are described and their significance for various metabolic abnormalities is reviewed. The tumor variant gamma3 from M2 isoenzyme of pyruvate kinase sensitive to L-cysteine inhibition, when over-expressed, can be used as a marker of tumorigenic transformation. It seems that this variant represents a tumor-specific oncoprotein, involved in a novel metabolic strategy of energy generation during increased cell proliferation.
Selective cobalamin malabsorption and the cobalamin-intrinsic factor receptor.
Authors: Gräsbeck R
Published: January 2020

The disease is characterised by cobalamin (Cbl) deficiency in children 0-5 years old, causing failure to thrive, infections, megaloblastic anaemia, neuropathy, and mild general malabsorption; slight proteinuria is common. Cbl injections produce remission, but Cbl malabsorption and proteinuria persist. About 250 cases have been reported. Dogs also have it. The heredity is autosomal and recessive. The physiological and pathological absorption mechanisms are described: Cbl liberated from food by digestion is first bound to haptocorrin, but in the intestine it is transferred to intrinsic factor. In the ileum the complex attaches to a receptor on the enterocytes; this requires neutral pH and Ca2+. The receptor is a membrane-bound glycoprotein consisting of multiple subunits. The receptor-ligand complex is endocytosed and degraded in lysosomes, and the vitamin is transferred to transcobalamin which carries it to tissues. The same receptor is strongly expressed in the kidneys, but urine also contains its activity which can be assayed for diagnosis. The basic lesion is an error in the ileal receptor. In the affected dogs the synthesised receptor is retained intracellularly. Urine and ileal biopsies from human cases contained little receptor but it had conserved affinity for the ligand. Recently examined Arab patients did not excrete reduced amounts of the receptor. Apparently, the disease has subsets, such as different structural errors in the receptor and possibly faulty transport inside the enterocyte. The cause of the proteinuria is unknown but kidney damage due to severe Cbl deficiency and an error in a multiligand renal receptor are among the possibilities.
The effect of dihydrotestosterone on transcription of prostatic acid phosphatase mRNA in human hyperplastic gland.
Authors: Dulińska J , Laidler P , Ostrowski W S , Mrozicki S , Gałka M
Published: January 2020

The effect of 5alpha-dihydrotestosterone (DHT) on the level of human prostatic acid phosphatase (hPAP) mRNA was studied using tissue slices from various benign prostatic hyperplastic glands. The absence of DHT in the incubation medium led to a gradual, significant decrease of the hPAP mRNA level. Addition of the hormone induced hPAP mRNA in a time- and dose-dependent manner. The maximal 2-4-fold induction by 10(-9) M DHT was observed after 3-5 h of incubation, and then the hPAP mRNA level was 6-20-fold higher than that in a parallel sample incubated without DHT. The results suggest that DHT is necessary to sustain the expression of hPAP in hyperplastic prostates.
2-Methyl-thiazolidine-2,4-dicarboxylic acid protects against paracetamol induced toxicity in human liver derived HepG2 cells.
Authors: Włodek L , Rommelspacher H
Published: January 2020

The effects of 2-methyl-thiazolidine-2,4-dicarboxylic acid (CP) on paracetamol-induced toxicity were investigated and evaluated in a human liver derived HepG2 cell line. Incubation of the cells with CP (2 mM and 10 mM) drastically attenuated the GSH and cysteine depletion caused by toxic concentrations of paracetamol (1 mM and 5 mM). When CP (10 mM) was introduced alone into the medium, the level of malondialdehyde and the reactive oxygen species were maintained at the control levels with a simultaneous increase of non-protein sulfhydryl in the cells. Thus, the results of our work prove that CP is a non-toxic precursor of cysteine and GSH, and successfully prevents paracetamol toxicity in HepG2 cells.
The effect of experimental neoplastic disease on malondialdehyde level and glutathione status in erythrocytes of rats.
Authors: Batko J
Published: January 2020

The level of lipid peroxidation products and the content of glutathione in erythrocytes of rats with Morris 5123 hepatoma at different stages of tumor development were examined. The content of endogenous malondialdehyde (MDA) was increased throughout all periods of tumor development as compared to the results for healthy rats. From the extent of MDA generation under oxidative stress we concluded that erythrocytes of Morris 5123 hepatoma bearing rats were more susceptible to autoxidation than those from control rats. The content of reduced glutathione (GSH) and oxidized glutathione (GSSG) was increased at the early stage of tumor growth. At the advanced stage of the disease both the content of GSH and the GSH/GSSG ratio were decreased while the content of GSSG remained at the elevated level.
Inhibition of mammalian topoisomerase I by 1-nitro-9-aminoacridines. Dependence on thiol activation.
Authors: Ciesielska E , Pastwa E , Szmigiero L
Published: January 2020

The cytotoxic activity, susceptibility to thiol activation and ability of eight 1-nitroacridine derivatives to stabilize the topoisomerase I-DNA cleavable complex, were compared. Among the acridines tested three compounds exhibited high ability to stabilize the cleavable complex. This ability was correlated with susceptibility to thiol activation as well as with cytotoxic activity. Our results suggest that 1-nitroacridine-DNA adducts interfering with topoisomerase I action may contribute to the lethal effects of some 1-nitroacridine derivatives.
Kainate-evoked modulation of gene expression in rat brain.
Authors: Kaminska B , Filipkowski R K , Biedermann I W , Konopka D , Nowicka D , Hetman M , Dabrowski M , Gorecki D C , Lukasiuk K , Szklarczyk A W , Kaczmarek L
Published: January 2020

Kainate is a glutamate analog that produces neuronal excitation resulting in seizures within hours following its intraperitoneal injection into adult rats. Then, at 2-3 days after the treatment, neurodegeneration of apoptotic character can be observed in limbic system. As a consequence, plastic reorganization and glial reactivation phenomena occur. These physiological and pathological responses are reflected by specific changes in gene expression, that can be dissected according to their spatio-temporal patterns. The early phase of gene expression observed in all hippocampal subfields appears to reflect a sudden burst of spiking activity. Changes in mRNA levels restricted to dentate gyrus are suggestive of a link to neuronal plasticity. The late gene expression response implies its correlation either to neuronal cell death or glial reactivation, depending on cellular localization of gene products. Thus analysis of the temporal and spatial gene expression pattern in the hippocampus after kainate treatment may provide clues revealing specific phenomena to which gene expression could be attributed.
New intron-containing human tRNA(Leu) genes.
Authors: Karwowska U , Szweykowska-Kulińska Z
Published: January 2020

Three new human nuclear tRNA(Leu) genes have been isolated and sequenced using the PCR technique. Two of them represent genes containing a CAA anticodon and both contain introns of 22 nucleotides in length but differing in sequence. Intron-containing prolongated anticodon stems can be folded into a secondary structure similar to that of yeast pre-tRNA(Leu). The evolutionary conserved secondary structure suggests the same role of intron sequences in the human and yeast pre-tRNA(Leu) maturation pathway.
Two plant signalling peptides: systemin and ENOD 40.
Authors: Barciszewski J , Legocki A B
Published: January 2020

Recently several new evidences have appeared on biological role of native short peptides. This is an overview on two of them occurring in plants: systemin and ENOD 40.
On the specific pattern of long chain polyprenols in green needles of Pinus mugo Turra.
Authors: Kazimierczak B , Hertel J , Swiezewska E , Chojnacki T , Marczewski A
Published: January 2020

In green needles of Pinus mugo the most abundant polyprenols occur as a mixture of prenologues in which the dominant alcohol is built of 16 isoprene units. The characteristic spectrum of polyprenols (prenol-15, -16 and -17) was the same irrespective of the location of plant and of distinct morphological differences observed in the various selected forms of this species. The constant pattern of the polyprenols spectrum was preserved throughout the 2-year life span of needles, although the level of polyprenols was increased 2-3-fold. The polyprenol pattern in Pinaceae family differs from species to species, thus it may serve as chemotaxonomic criterion within this systematic group.
Phosphorylation of sucrose synthase from maize seedlings.
Authors: Lindblom S , Ek P , Muszyńska G , Ek B , Szczegielniak J , Engström L
Published: January 2020

Two isoforms of sucrose synthase (SS1 and SS2) from maize (Zea mays, var. Mona) seedlings co-purified with a calcium and phospholipid dependent protein kinase. The enzymatic preparation obtained gave a positive reaction with the antibody against mammalian protein kinase C. Maize sucrose synthase was phosphorylated by the endogenous protein kinase. Also, mammalian protein kinases (protein kinase C and protein kinase A) were able to phosphorylate the 86 kDa subunit of sucrose synthase. When excised seedlings were fed [32P]orthophosphate, sucrose synthase was also phosphorylated. Microsequencing of in vivo labelled enzyme has shown phosphorylation of Ser-15 in SS2. The present work provides evidence that maize sucrose synthase is the physiological substrate of the endogenous calcium and phospholipid dependent protein kinase(s).
Characterization of two lipopolysaccharide types isolated from Rhizobium galegae.
Authors: Räsänen L A , Russa R , Urbanik T , Choma A , Mayer H , Lindström K
Published: January 2020

Lipopolysaccharides (LPS) of Rhizobium galegae, a symbiotically nitrogen-fixing species of root-nodule bacteria, were isolated by the phenol-water method from strain HAMBI 1461, the LPS of which resembled enterobacterial smooth type LPS, and from strains HAMBI 1174 and HAMBI 1208, the LPSs of which resembled rough type LPS. The results of PAGE analysis of LPSs, Bio-Gel P2 gel filtration of polysaccharide fractions and the presence of deoxysugars and 4-O-methyl-deoxysugar both in the rough and smooth LPSs suggested that rough LPS contained a short O-antigenic polysaccharide for which we propose the name short O-chain LPS. Accordingly, the smooth LPS is called long O-chain LPS. Despite of the differences in the structure of LPS of R. galegae, all strains were equally effective in nodulating their hosts. The short O-chain LPS of R. galegae showed many features similar to those of phylogenetically related agrobacteria.
An enigma: the role of viral RNA aminoacylation.
Authors: Haenni A L , Chapeville F
Published: January 2020

The first demonstration on the aminoacylation capacity of the RNA genome of a plant virus appeared more than 25 years ago. Shortly thereafter, aminoacylation of the RNA genome of a number of other plant viruses was observed. This led to considerable work on the tRNA-like region of these viral RNAs, and to the first demonstration of the presence of pseudoknots in their folding pattern. In spite of the vast amount of efforts put into trying to understand the reason for the aminoacylation capacity of certain viral RNA genomes, as yet no clear general conclusion emerges. It rather looks as though the reason for aminoacylation may be different for different viruses, and that aminoacylation may operate at different levels in the virus life cycle. Given that certain RNA viruses possess structures which resemble that of tRNAs at their 5'- or 3'-termini, it is most likely that convergent evolution may have dominated the appearance of such structures in the virus world.
A novel restriction endonuclease UnbI, a neoschizomer of Sau96I from an unidentified psychrofilic bacterium from Antarctica is inhibited by phosphate ions.
Authors: Kawalec M , Borsuk P , Piechula S , Stepień P P
Published: January 2020

A novel type II restriction endonuclease UnbI was isolated from an unidentified psychrofilic bacterial strain from Antarctica. UnbI recognizes and cleaves the sequence 5'-GGNCC-3', producing 5 nucleotide long sticky ends. In this respect it differs from its neoschizomer Sau96I and all other restriction enzymes recognizing this sequence. UnbI has a relatively low temperature optimum of 15 degrees C to 20 degrees C and its activity is completely inhibited by inorganic phosphate.
Continuous assay for acid phosphatase using 1-naphthyl phosphate as a substrate.
Authors: Luchter-Wasylewska E
Published: January 2020

The described continuous acid phosphatase assay is based on kinetics of the release of 1-naphthol in the course of the enzyme-catalyzed hydrolysis of 1-naphthyl phosphate, measured at 320 nm in aqueous solution and at 322 nm in sodium-bis(2-ethylhexyl)sulfosuccinate isooctane-water reverse micelles in a broad pH range (1.0-8.2). The method allows precise determination of the initial rate of the reaction and therefore may be used in the steady-state and pre-steady-state studies on the phosphatase-catalyzed reaction. The kinetic parameters (Km and kcat) for human prostatic acid phosphatase in aqueous solution and in reverse micelles, at pH 3.8, 4.5 and 5.7, by the proposed 1-naphthyl phosphate assay have been determined.
Structural and energetic aspects of protein-protein recognition.
Authors: Otlewski J , Apostoluk W
Published: January 2020

Specific recognition between proteins plays a crucial role in a great number of vital processes. In this review different types of protein-protein complexes are analyzed on the basis of their three-dimensional structures which became available in recent years. The complexes which are analyzed include: those resulting from different types of recognition between proteinase and protein inhibitor (canonical inhibitors of serine proteinases, hirudin, inhibitors of cysteine proteinases, carboxypeptidase inhibitor), barnase-barstar, human growth hormone-receptor and antibody-antigen. It seems obvious that specific and strong protein-protein recognition is achieved in many different ways. To further explore this question, the structural information was analyzed together with kinetic and thermodynamic data available for the respective complexes. It appears that the energy and rates of specific recognition of proteins are influenced by many different factors, including: area of interacting surfaces; complementarity of shapes, charges and hydrogen bonds; water structure at the interface; conformational changes; additivity and cooperativity of individual interactions, steric effects and various (conformational, hydration) entropy changes.
Helix-coil transition theories. Are they correct?
Authors: Bierzyński A , Pawłowski K
Published: January 2020

Principles of contemporary theoretical description of alpha-helix formation by polypeptide chains in water solution are shortly presented and critically discussed. The theory treats the unfolded state of a peptide as "random coil"--an ideal conformation quite distant from reality. We suggest that for this reason the helix propagation parameters of amino-acid residues, determined using series of model peptides with different sequential patterns, are not the same. Interpretation of the so called "nucleation parameter" is erroneous. In fact, it is not determined by the helix nucleation process but rather by a specific situation of residues at the helix N- and C-termini, and it strongly depends on solvation of their NH and CO groups, respectively. Consequently, helical segments with terminal sequences dominated by residues with strongly hydrophobic, bulky side chains can be very unstable. We postulate that an unexpectedly high stability of very short, pre-nucleated helices studied by us arises from a "helix end separation effect": separated helix termini are better solvated than when they overlap each other. Because of this effect, helix initiation may be much more difficult than predicted by the theoretical "helix nucleation parameters".
Disulfide bonds in protein folding studies: friends or foes?
Authors: Dadlez M
Published: January 2020

The studies on protein folding pathways utilizing disulfide bonds as reporter groups in several protein model systems are reviewed. Implications for a general mechanism of protein folding are discussed. An updated folding pathway for bovine pancreatic trypsin inhibitor (BPTI) based on recent data is proposed.
Elucidation of neurophysin/bioligand interactions from molecular modeling.
Authors: Kaźmierkiewicz R , Czaplewski C , Ciarkowski J
Published: January 2020

This is a review of our recent modeling work aimed at: (i) development and assessment of techniques for reliable refinement of low-resolution protein structures and (ii) using these techniques, at solving specific problems pertinent to neurophysin-bioligand interactions. Neurophysins I and II (NPI and NPII) serve in the neurosecretory granules of the posterior pituitary as carrier proteins for the neurophyseal hormones oxytocin (OT) and vasopressin (VP), respectively, until the latter are released into blood. NPs are homologous two-domain, sulphur rich small proteins (93-95 residues, 7 disulphide bridges per monomer), capable of being aggregated. The C2 symmetrical NPI2 and NPII2 homodimers, and the (NPI/OT)2 and (NPII/VP)2 heterotetramers, all believed to be the smallest functional units, were modeled using low-resolution structure information, i.e. the C alpha-carbon coordinates of the homologous NPII/dipeptide complex as a template. The all-atom representations of the models were obtained using the SYBYL suite of programs (by Tripos, Inc.). Subsequently, they were relaxed, using a constrained simulated annealing (CSA) protocol, and submitted to about 100 ps molecular dynamics (MD) in water, using the AMBER 4.1 force field. The (NPI/OT)2 and (NPII/VP)2 structures, averaged after the last 20 ps of MD, were remarkably similar to those recently reported either for NPII/dipeptide or NPII/oxytocin complex in the solid state (Chen et al., 1991, Proc. Natl. Acad. Sci., U.S.A. 88, 4240-4244; Rose et al., 1996, Nature Struct. Biol. 3, 163-169). The results indicate that the 3(10) helices (terminating the amino domains) and the carboxyl domains are more mobile than the remainder of the NP monomers. The hormones become anchored by residues 1-3 and 6 to the host, leaving residues 4-5 and 7-9 exposed on the surface and free to move. A cluster of attractive interactions, extending from the ligand binding site, Tyr-24-Ile-26 of unit 1(2), to the inter-monomer interface Val-36 of unit 1(2), Cys-79 and Ile-72 of unit 2(1), is clearly seen. We suggest that both these interactions as well as the increased mobility of the 3(10) helix and the carboxyl domain may contribute to the allosteric communication between the ligand and the unit1-unit2 interface.