High Polymorphism Research Articles

Genetic diversity analysis of indigenous pomegranate (Punica granatum L.) germplasm lines

Pomegranate (Punica granatum L.) is an ancient edible fruit crop well recognized for its immense nutraceutical and medicinal properties. Precise morphological characterization of wild, exotic and commercial (cultivar) varieties and understanding the molecular variability in perennial crops like pomegranate is essential for developing varietal DNA fingerprints, identifying true-to-type of genotypes, to avoid duplication and overcome the problem of clonal admixture. It has become a challenge to identify varieties based solely on observable phenotypic traits due to dynamic environmental factors that influence physical traits and increasing number of varieties. Hence, the implementation of stable molecular markers is the best complementary biotechnological tool, which fulfil the above requirements. In our first objective, we identified 24 polymorphic SSR markers out of 40. These SSRs screened on 13 different varieties of pomegranate. The PIC value ranged from 0.13 to 0.37 (mean 0.25) and heterozygosity percent ranged from 0.14% to 0.50% (mean 0.35%). Highest PIC value and heterozygosity observed in PgSSR78 marker. Similarity coefficient matrix showed the genetic distance between the twenty-four varieties, ranged from 0.58 to 0.99. Maximum similarity was observed between Alah and Khandari. Minimum similarity was found between IC318743 and 1185 followed by Maha and 1185. PgSSR16, PgSSR23, PgSSR49, PgSSR60, PgSSR32, PgSSR40, PgSSR78 markers were found with high PIC value and heterozygosity and these primers could be useful for pomegranate cultivar identification. From this study, microsatellite markers have proven to be very useful marker for developing varietal identification marker at early growth stage due to its high polymorphism, abundance, multi-allelic and co-dominant inheritance

The Potential of Complementary Sex-Determiner Gene Allelic Diversity for Studying the Number of Patrilines within Honeybee Colonies

Polyandry, a fundamental aspect of honeybee biology, influences genetic diversity within bee colonies. The Csd gene, responsible for sex determination, exhibits a high intraspecific polymorphism, making it a promising candidate for studying patrilines. This study investigates the potential of the complementary sex-determiner gene (Csd) as a marker for genetic studies of honeybee colonies, comparing its efficacy with standard microsatellite markers. A worker bee brood from five colonies was genotyped using both Csd and microsatellite markers. The results showed that Csd alleles offer higher variability than microsatellite markers, providing a superior resolution in genotyping. The number of distinct Csd alleles in each colony surpassed microsatellite markers, demonstrating the potential of Csd for detailed genetic analyses. Despite challenges in Csd amplification efficiency, a two-step nested PCR protocol proved effective. Interestingly, Csd genotyping alone identified more patrilines than the set of five microsatellite markers, emphasizing its efficacy. Combining Csd and microsatellite genotyping enhances the resolution of genetic studies in honeybee colonies, offering valuable insights into genetic diversity, reproductive success, and social dynamics. The Csd gene emerges as a promising tool for advancing genetic studies in honeybee populations.

Development of a Gene-Based Soybean-Origin Discrimination Method Using Allele-Specific Polymerase Chain Reaction.

A low soybean self-sufficiency rate in South Korea has caused a high import dependence and considerable price variation between domestic and foreign soybeans, causing the false labeling of foreign soybeans as domestic. Conventional soybean origin discrimination methods prevent a single-grain analysis and rely on the presence or absence of several compounds or concentration differences. This limits the origin discrimination of mixed samples, demonstrating the need for a method that analyzes individual grains. Therefore, we developed a method for origin discrimination using genetic analysis. The whole-genome sequencing data of the Williams 82 reference cultivar and 15 soybean varieties cultivated in South Korea were analyzed to identify the dense variation blocks (dVBs) with a high single-nucleotide polymorphism density. The PCR primers were prepared and validated for the insertion-deletion (InDel) sequences of the dVBs to discriminate each soybean variety. Our method effectively discriminated domestic and foreign soybean varieties, eliminating their false labeling.

Evaluation of DNA extraction methods for molecular traceability in cold pressed, solvent extracted and refined groundnut oils

Groundnut oil (GNO)/ peanut oil is one of the agro-food products with great economic value and hence an attractive target for adulteration and mislabeling. Simple Sequence Repeats (SSR) are markers of choice for DNA fingerprinting studies as they exhibit high polymorphism due to variable number of repeats. Hence, this study was designed to evaluate and optimized a method for DNA isolation from groundnut oil and study the possibility of using the isolated DNA for molecular traceability using SSR markers. Four methods to isolate DNA from groundnut oil were evaluated. All the four methods were modified CTAB protocols, but differed in procedures forextraction, buffer compositions, amount of oil used and DNA carriers. For molecular traceability of oils, extraction and recovery of DNA from edible oil is a key step, especially in refined oils. A method that employed DNA enrichment prior to extraction with CTAB buffer yielded amplifiable DNA from cold pressed GNO, crude hexaneextracted GNO and refined GNO. The optimized method for isolation of DNA from groundnut oil is simple, efficient, less costly and reproducible when compared to chromatography and spectroscopy based techniques.

High production MBL2 polymorphisms protect against COVID-19 complications in critically ill patients: A retrospective cohort study

Mannose-binding lectin (MBL) binds to SARS-CoV-2, inhibits infection of susceptible cells, and activates the complement system via the lectin pathway. In this study, we investigated the association of MBL2 polymorphisms with the risk of hospitalization and clinical worsening in patients with COVID-19. A total of 550 patients with COVID-19 were included (94 non-hospitalized and 456 hospitalized). Polymorphisms in MBL2 exon 1 (codons 52, 54 and 57) and promoter region (−550, −221, and +4) were determined by real-time PCR. MBL and complement proteins were measured by Luminex. A higher frequency of the H/H genotype and the HYPA haplotype was observed in non-hospitalized patients when compared to hospitalized. In addition, critically ill patients carrying haplotypes associated with high MBL levels (HYPA/HYPA + HYPA/LYPA + HYPA/LYQA + LYPA/LYQA + LYPA/LYPA + LYQA/LYQA + LXPA/HYPA + LXPA/LYQA + LXPA/LYPA) were protected against lower oxygen saturation levels (P = 0.02), use of invasive ventilation use (P = 0.02, OR 0.38), and shock (P = 0.01, OR 0.40), independent of other potential confounders adjusted by multivariate analysis. Our results suggest that variants in MBL2 associated with high MBL levels may play a protective role in the clinical course of COVID-19.

Retracted: Correlation between High Myopia Susceptibility and Polymorphisms of RASGRF1 Gene among College Students in Zhejiang.

[This retracts the article DOI: 10.1155/2023/6767410.].

A Multiplex PCR System of Novel Microsatellite Loci for Population Genetic Application in Walnuts.

Multiplex polymerase chain reaction (PCR) of microsatellite loci allows for simultaneous amplification of two or more pairs of primers in a single PCR reaction; hence, it is cost and time effective. However, very few attempts have been reported in non-model species. In this study, by combining a genome-based de novo development and cross-species application approach, a multiplex PCR system comprising 5 PCR reactions of 33 microsatellites consisting of 26 novel genomic and 7 literature-sourced loci was tested for polymorphisms, cross-species transferability, and the ability to assess genetic diversity and population structure of three walnut species (Juglans spp.). We found that the genome-based approach is more efficient than other methods. An allelic ladder was developed for each locus to enhance consistent genotyping among laboratories. The population genetic analysis results showed that all 33 loci were successfully transferred across the three species, showing high polymorphism and a strong genetic structure. Hence, the multiplex PCR system is highly applicable in walnut species. Furthermore, we propose an efficient pipeline to characterize and genotype polymorphic microsatellite loci. The novel toolbox developed here will aid future ecology and evolution studies in walnut and could serve as a model for other plant species.

Comparison of the variability and nitrogen-fixing activity of rhizobia strains isolated from <i>Trifolium Hybridum</i> L. and <i>Galegaorientalis</i> Lam. nodules at different stages of plant vegetation

BACKGROUND: The beginning of the life cycle of a leguminous plant in its natural habitat is usually associated with interaction with nodule bacteria in order to form a nitrogen-fixing symbiosis. In a short period of time, a plant needs to “choose” suitable microsymbionts for itself. Since a wide variety of rhizobial strains is formed in the rhizosphere of legumes, the choice made by the macrosymbiont will further influence its productivity.
 AIM: The purpose of our work was to compare the principles of selection by different plants of their microsymbionts at different stages of plant development.
 MATERIALS AND METHODS: Nodule bacteria Trifolium hybridum L. and Galegaorientalis Lam. were taken into the study. Their genetic diversity was studied by the RAPD method, a phylogenetic analysis of bacteria and their symbiotic nodC and nifH genes was carried out, and their nitrogen-fixing activity was assessed.
 RESULTS: It was found that the rhizobia that form nodules on the roots of the studied leguminous plants at different stages of their vegetation have certain patterns. It was found that the highest polymorphism and specific nitrogen-fixing activity are characteristic of bacteria obtained from nodules formed at the initial stage of vegetation.
 CONCLUSIONS: We assume that the plasticity of the rhizobia genome gives the host plant the ability to more flexibly adjust its nitrogen-fixing apparatus to changes in growing conditions.

Baddeleyite microstructural response to shock metamorphism in three enriched shergottites and implications for U–Pb geochronology

Baddeleyite (monoclinic zirconia; m-ZrO2) occurs as a late-stage accessory mineral in shergottites and has been used to determine U–Pb igneous crystallization ages via in-situ secondary ion mass spectrometry (SIMS). During shergottite ejection from the surface of Mars, baddeleyite develops a range of microstructures primarily due to a series of shock-induced transformations to high pressure and temperature polymorphs. It remains poorly constrained to what extent U–Pb systematics in baddeleyite are sensitive to shock conditions experienced by shergottites. To investigate this, we examined baddeleyite in the enriched shergottites Jiddat al Harasis (JaH) 479, Northwest Africa (NWA) 10299, and NWA 12919, which bridge the gap in shock conditions represented in previous microstructural studies. Electron backscatter diffraction (EBSD) analysis reveals that although some baddeleyite grains retain magmatic microstructures (i.e. homogenous crystallographic orientations and twinning of igneous origin), there is widespread phase transformation to high-pressure orthogonal polymorphs (o-ZrO2) followed by reversion. JaH 479 contains more grains with preserved magmatic microstructures than the other two shergottites, suggesting that it experienced lower bulk shock pressures. Nanometer-scale reverted m-ZrO2 in NWA 10299 and NWA 12919 further points to insufficient post-shock temperatures; this contrasts with JaH 479 where greater variation in local temperature conditions enabled the development of µm-scale domains of reverted m-ZrO2. Individual grains that are separated into two distinct microstructural domains may reflect controls on shock propagation due to relative density contrast among the surrounding phases.SIMS U–Pb baddeleyite analysis yields igneous crystallization ages of 210 ± 9 Ma (JaH 479), 196 ± 11 Ma (NWA 10299), and 188 ± 11 Ma (NWA 12919). At the SIMS resolution, we find no clear evidence for significant Pb loss in the surveyed baddeleyite grains, suggesting that temperatures during the formation of both nm-scale and µm-scale reverted m-ZrO2 in the three shergottites were insufficient to cause significant Pb diffusion. Given the robust baddeleyite U–Pb isotope systematics in the majority of shergottites dated by SIMS methods thus far, we argue that shock conditions experienced by the bulk of shergottites were insufficient to introduce significant U–Pb isotopic mobility, which is limited to grains showing microstructural evidence for extensive post-shock heating and recrystallization. Our findings place new constraints on baddeleyite microstructural response to shock conditions of shergottite ejection and demonstrate that microstructural observations are critical when using baddeleyite as a chronometer in shocked planetary materials.

Phenotypic and genotypic variability among exotic arabica coffee genotypes using morphological and molecular markers (SRAP)

Coffea arabica is said to have low genetic variability, however more information is still needed about the extent of diversity present in the arabica coffee gene pool by evaluating existing genetic resources present in India. The study therefore was conducted to assess the phenotypic and genotypic variability in arabica coffee germplasm accessions. Significant variation was observed among coffee accessions for the traits studied indicating the presence of diversity. Out of 20 traits, per cent ‘A’ grade bean contributed maximum to the diversity (63.29 %). The 41 arabica coffee accessions were grouped into six clusters. The maximum intra-cluster and inter cluster distance (D2 = 737.34) was revealed by cluster V (7 genotypes) and cluster II and VI (D2 = 8544.21), respectively. Principle Component Analysis displayed 79.50% of variability. Observations on Coffee Leaf Rust disease incidence showed that mean disease severity infection was ranged from 1.34 to 32.67%. On the other hand, molecular analysis of 10 SRAP primers established high rate of polymorphism with an average PIC value of 0.74. The UPGMA clustering grouped arabica coffee genotypes into two major clusters. The similarity matrix coefficient was ranged from 0 to 94%. SRAP marker demonstrated high polymorphism rate can be utilized for future crop improvement program in coffee. Study established high phenotypic but low genetic diversity among the arabica coffee accessions based on morphological and molecular markers, respectively and identified high yielding, coffee leaf rust disease resistant accessions which showed possibility of developing improved varieties through breeding.

Enhanced Seebeck Coefficient of Cu-Bi-S Heterogeneous Composite Synthesized via Solvothermal Method

We report on a heterogeneous composite Cu-Bi-S system for thermoelectric applications. This composite was synthesized by an efficient solvothermal method. The dominant phase of Cu3BiS3 showed a weak polymorphic nature at room temperature. The low polymorphic to first-order phase transition was obtained at 391.5 K where the carriers dominated the transport properties. The structure changed from P212121 to modulated intermediate polymorphic continues up to 463 K followed by changes to high polymorph. The ionic conduction switched in the intermediate modulate structure above 408 K. The phase boundary scattering mechanism was attributed to the enhancement of the Seebeck coefficient. The maximum power factor of 2.76 μWm−1K−2 at 443 K persisted in this heterogeneous composite where Cu3BiS3 phase existed as an intermediate polymorph.

Development of a 39 MM-InDel multiplex assay for the forensic application.

Insertion/deletion polymorphisms (InDels) are a category of highly prevalent markers in the human genome, characterized by their distinctive attributes, including short amplicon sizes and low mutation rates, which have shown great potential in forensic applications. Multi-allelic InDel and multi-InDel markers, collectively abbreviated as MM-InDels, were developed to enhance polymorphism by the introduction of novel alleles. Nevertheless, the relatively low mutation rates of InDels, coupled with the founder effect, result in distinct allele frequency distributions among populations. The divergent characteristics of InDels in different populations also pose challenges to the establishment of universally efficient InDel multiplex assays. To enhance the system efficiency of the InDel assay and its applicability across diverse populations, 39 MM-InDels with high polymorphism in five different ancestry superpopulations were selected from the 1000 Genomes Project dataset and combined with an amelogenin gender marker to construct a multiplex assay (named MMIDplex). The combined power of discrimination and the cumulative probability of exclusion of 39 MM-InDels were 1-1.3×10-23 and 1-9.83×10-6 in the Chinese Han population, and larger than 1-10-19 and 1-10-4 in the reference populations, relatively. These results demonstrate that the MMIDplex assay has the potential to obtain sufficient power for individual identification and paternity test in global populations.

Genetic Diversity and Phylogenetic Relationships among Jatropha curcas L. Genotypes from Eastern India

Genetic diversity and relationships among 31 genotypes collected from wide geographical range in eastern India was studied employing Random Amplified Polymorphic DNA (RAPD) markers. 19 markers (identified out of 25) produced 139 band in total. Off these 139 bands, 131 bands were polymorphic exhibiting a high polymorphism of 94.24%. Similarity indices estimated on the basis of RAPD primers ranged widely from 0.44 to 0.83 which suggests that these accessions represent genetically diverse population possibly due to predominance of cross pollination and seed source variability. Genotyping data obtained for RAPD primer across collected accessions were used to generate the UPGMA - based phylogenetic tree which shows two major clusters. The cluster I consisted of 16 genotypes from two states Jharkhand and Odisha (Chotanagpur and Eastern plateau region) while 15 accessions from West Bengal and Bihar (Indo Gangetic plains region) were grouped together in the Cluster II. This clear alignment of accessions into two different clusters as per geographical regions was probably due to different growing conditions in two clusters.

Characterization of heterogeneity in popular rice landrace through field and molecular evaluation

ContextIdentification and purification of the landrace Chittimuthyalu using stability and molecular heterozygosity can be useful for rice diversity. ObjectivesThe present study reports the characterization of 12 genotypic variants of Chittimuthyalu in terms of (i) variation and correlation among agromorphological, grain quality and nutrient traits, viz., Zn and Fe; (ii) stability across years; and (iii) characterization and heterozygosity. MethodsA total of twelve genotypic variants were identified based on field-level agromorphological observations in the Chittimuthyalu landrace. For identification of a stable genotypic variant for grain Zn, genotype by environment (G × E) interaction was analyzed across three years using additive main effects and multiplicative interaction (AMMI) model and genotype main effects plus G × E (GGE) model for multienvironment data analysis along with principal component analysis (PCA). Correspondingly, twenty-five high polymorphism information content (PIC) RM markers were used for the identification of molecular heterozygosity in landrace. ResultsStepwise regression analysis of phenotype revealed the interdependence of zinc in polished rice (ZPR), iron in polished rice (IPR), and single plant yield (SPY) and the positive association of grain Zn with IPR and SPY. Based on GGE and AMMI analyses of the variants, MCM3 was found to be stable across the environments for ZPR. Out of 46% polymorphic RM markers, seven markers (RM10149, RM13347, RM21749, RM13263, RM10361, RM12276 and RM474) were heterozygous. Heterozygous alleles were observed in eight variants (MCM2, MCM3, MCM5, MCM6 MCM7, MCM8, MCM10 and MCM12). The polymorphic information content (PIC) of the markers ranged from 0.58 to 0.88, with an average of 0.64. The percentage of the most common allele frequencies ranged from 4.2 to 95.8 across the markers. RM13347 showed nine markertrait associations with P ≤ 0.05 and R2 ranging from 2.3% to 14.3% with a mean of 7.74%. ConclusionsThe present study has revealed the inherent heterogeneity in landraces in terms of their agromorphological, yield-related and nutritional quality traits. A promising genetic stock (MCM3) was identified as a donor for high grain ZPR and was registered as genetic stock. ImplicationsThe identified genetic stock is being shared with breeders in the breeding programme and farmers for the multiplication of high grain Zn rice.

Genetic diversity, population structure, and DNA fingerprinting of Ailanthus altissima var. erythrocarpa based on EST-SSR markers

Ailanthus altissima var. erythrocarpa is an A. altissima variety with high economic, ecological and ornamental value, but there have been no reports on the development of SSR primers for it. According to the SSR primer information provided by the transcriptome of A. altissima var. erythrocarpa, 120 individuals with different redness levels were used to screen polymorphic primers. Transcriptomic analysis revealed 10,681 SSR loci, of which mononucleotide repeats were dominant (58.3%), followed by dinucleotide and trinucleotide repeats (16.6%, 15.1%) and pentanucleotide repeats (0.2%). Among 140 pairs of randomly selected primers, nineteen pairs of core primers with high polymorphism were obtained. The average number of alleles (Na), average number of effective alleles (Ne), average Shannon’s diversity index (I), average observed heterozygosity (Ho), average expected heterozygosity (He), fixation index (F) and polymorphic information content (PIC) were 11.623, 4.098, 1.626, 0.516, 0.696, 0.232 and 0.671, respectively. Nineteen EST-SSR markers were used to study the genetic diversity and population structure of A. altissima var. erythrocarpa. The phylogenetic tree, PCoA, and structure analysis all divided the tested resources into two categories, clearly showing the genetic variation between individuals. The population showed high genetic diversity, mainly derived from intraspecific variation. Among nineteen pairs of primers, 4 pairs (p33, p15, p46, p92) could effectively distinguish and be used for fingerprinting of the tested materials. This study is of great significance for genetic diversity analysis and molecular-assisted breeding of A. altissima var. erythrocarpa.

Single nucleotide polymorphism rs527236194 of the cytochrome B gene (MT-CYB) is associated with alterations in sperm parameters.

The mitochondrial genome is substantially susceptible to mutations and has high polymorphism due to structural features, location, and lack of recombinant variability, as its inheritance is strictly maternal. All of these events can be accompanied by the accumulation of mitochondrial single nucleotide polymorphisms (mtSNPs) in the sperm. The aim of this research was to analyze the influence of mutations in the MT-CYB gene on sperm quality. We conducted a case‒control study to identify mutations in the mitochondrial cytochrome B (MT-CYB) gene in men with asthenoteratozoospermia (89 cases) and oligoasthenoteratozoospermia (65 cases). The comparison group consisted of 164 fertile men. Somatic cell lysis followed by mtDNA extraction was conducted to analyze three mtDNA polymorphisms, rs28357373 (T15629C (Leu295=), rs527236194 (T15784C (p.Pro346=), rs2853506 (A15218G, p.Thr158Ala). Detection and genotyping of polymorphic loci in the MT-CYB gene was performed using the TaqMan allelic discrimination assay. To verify mutations in the MT-CYB gene, automated Sanger DNA sequencing was used. We found that rs527236194 was associated with asthenoteratozoospermia. rs28357373 in the MT-CYB gene did not show any polymorphism in the analyzed groups, which indicates a rare frequency of the TT genotype in our region. Rs28357373 and rs2853506 are not associated with male sperm abnormalities in the Volga-Ural region. The association of the rs527236194 polymorphic variant with sperm parameter alterations suggests its role in the pathophysiology of male infertility and requires further investigation in larger samples.

Effect of X-rays on Seedling Pigment, Biochemical Profile, and Molecular Variability in Astrophytum spp.

Cacti are important in agricultural economies and one of the most popular horticultural plant groups. The genus Astrophytum is one of the most valuable and desirable cacti for growers and collectors around the world. By selecting the appropriate breeding methods to induce variations in combination with modern biotechnology tools for rapid change detection, it is possible to meet the challenges of the modern world in creating new variability in plants. However, there exists a lack of research concerning the impact of ionizing radiation on cacti. The aim of the study was to assess the effects of X-rays at different doses (0 Gy—control, 15, 20, 25, and 50 Gy) on the dynamics of seed germination in vitro, changes in the color of seedlings, biochemical changes in the content of metabolites and changes at the molecular level in Astrophytum spp. ‘Purple’. A significant effect of X-rays on the induction of genetic variation was observed. Remarkably high polymorphism rates were observed, ranging from 59.09% for primer S12 to a full 100.0% for S3 and S8, as determined by the SCoT (Start-Codon-Targeted) marker. In addition, a large variation in the content of plant pigments (anthocyanins, carotenoids, chlorophyll a, and chlorophyll b) was noted. Additionally, discernible alterations in the color of the tested cactus seedlings, assessed by the RHSCC catalog, were attributed to the impact of ionizing radiation. These findings hold promise for the application of radiomutation breeding in acquiring new cactus cultivars.

Genetic Structure and Diversity of Dalbergia nigra from Brazilian Atlantic Forest Fragments

Dalbergia nigra is a long-living tree endemic to the Atlantic Rain Forest. Due to its high commercial value, this species has been widely exploited for timber production and is now endangered. It is widely known that understanding patterns of genetic structure is paramount for conserving threatened species. We analyzed the genetic diversity of 140 individuals from four different forest fragments in the southern region of Bahia, Brazil, to verify the possible effects of fragmentation on these populations and provide information for conservation initiatives. High polymorphism levels were detected from the genotyping of nine microsatellite loci (mean HE = 0.733). All populations showed high genetic diversity; however, a reduction of genetic diversity was detected in each population (HO < HE). The average fixation index was high and significant (f = 0.167), which could be due to the occurrence of inbreeding, the Wahlund effect, reproductive system, or from null alleles. Genetic differentiation among populations was high (mean θP = 0.118), suggesting strong isolation, a pattern consistent with historically low gene flow. The Bayesian analysis revealed five different genetic groups, among which three groups correspond to three different forest fragments, and two groups showed the genetic subdivision of individuals from the other forest fragment. Based on our results, the suggested conservation strategy for D. nigra populations in the southern region of Bahia, Brazil, involves high environmental investments to protect all sampled forest fragments and individuals. Another strategy would be to collect seeds from all individuals from the sampled fragments and start a new population with human interference in its evolutive history inside a protection unit.

Polymorphism of virulence genes and biofilm associated with in vitro induced resistance to clarithromycin in Helicobacter pylori

BackgroundClarithromycin-containing triple therapy is commonly used to treat Helicobacter pylori infections. Clarithromycin resistance is the leading cause of H. pylori treatment failure. Understanding the specific mutations that occur in H. pylori strains that have evolved antibiotic resistance can help create a more effective and individualised antibiotic treatment plan. However, little is understood about the genetic reprogramming linked to clarithromycin exposure and the emergence of antibiotic resistance in H. pylori. Therefore, this study aims to identify compensatory mutations and biofilm formation associated with the development of clarithromycin resistance in H. pylori. Clarithromycin-sensitive H. pylori clinical isolates were induced to develop clarithromycin resistance through in vitro exposure to incrementally increasing concentration of the antibiotic. The genomes of the origin sensitive isolates (S), isogenic breakpoint (B), and resistant isolates (R) were sequenced. Single nucleotide variations (SNVs), and insertions or deletions (InDels) associated with the development of clarithromycin resistance were identified. Growth and biofilm production were also assessed.ResultsThe S isolates with A2143G mutation in the 23S rRNA gene were successfully induced to be resistant. According to the data, antibiotic exposure may alter the expression of certain genes, including those that code for the Cag4/Cag protein, the vacuolating cytotoxin domain-containing protein, the sel1 repeat family protein, and the rsmh gene, which may increase the risk of developing and enhances virulence in H. pylori. Enhanced biofilm formation was detected among R isolates compared to B and S isolates. Furthermore, high polymorphism was also detected among the genes associated with biofilm production.ConclusionsTherefore, this study suggests that H. pylori may acquire virulence factors while also developing antibiotic resistance due to clarithromycin exposure.

Telomere and subtelomere high polymorphism might contribute to the specificity of homologous recognition and pairing during meiosis in barley in the context of breeding

Barley (Hordeum vulgare) is one of the most popular cereal crops globally. Although it is a diploid species, (2n = 2x = 14) the study of its genome organization is necessary in the framework of plant breeding since barley is often used in crosses with other cereals like wheat to provide them with advantageous characters. We already have an extensive knowledge on different stages of the meiosis, the cell division to generate the gametes in species with sexual reproduction, such as the formation of the synaptonemal complex, recombination, and chromosome segregation. But meiosis really starts with the identification of homologous chromosomes and pairing initiation, and it is still unclear how chromosomes exactly choose a partner to appropriately pair for additional recombination and segregation. In this work we present an exhaustive molecular analysis of both telomeres and subtelomeres of barley chromosome arms 2H-L, 3H-L and 5H-L. As expected, the analysis of multiple features, including transposable elements, repeats, GC content, predicted CpG islands, recombination hotspots, G4 quadruplexes, genes and targeted sequence motifs for key DNA-binding proteins, revealed a high degree of variability both in telomeres and subtelomeres. The molecular basis for the specificity of homologous recognition and pairing occurring in the early chromosomal interactions at the start of meiosis in barley may be provided by these polymorphisms. A more relevant role of telomeres and most distal part of subtelomeres is suggested.