Synthesis and antimicrobial activity of novel 1,4,5-triphenyl-1<Emphasis Type="Italic">H</Emphasis>-imidazol-[1,2,3]-triazole derivatives

Novel 1-phenyl-4-((4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenoxy)methyl)-1H-1,2,3-triazole derivatives were synthesized by click chemistry reaction and screened for antimicrobial activity against grampositive and gram-negative bacterial and fungal species. All the compounds were characterized by ¹H and ¹³C NMR, IR, and mass spectral data. The results of antibacterial study indicated that 1-(4-nitrophenyl)-4-((4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenoxy)methyl)-1H-1,2,3-triazole, 1-(4-(4-((4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenoxy)methyl)-1H-1,2,3-triazol-1-yl)phenyl)ethanone, 1-(2,6-dichloro-4-nitrophenyl)-4-((4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenoxy)methyl)-1H-1,2,3-triazole, and 1-(2-methoxy-4-nitrophenyl)-4-((4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenoxy)methyl)-1H-1,2,3-triazole showed appreciable antibacterial activity while 1-(4-fluorophenyl)-4-((4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenoxy) methyl)-1H-1,2,3-triazole, 1-(2,6-dichloro-4-nitrophenyl)-4-((4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenoxy)methyl)-1H-1,2,3-triazole, and 1-(4-methoxyphenyl)-4-((4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenoxy)methyl)-1H-1,2,3-triazole emerged as the most potential antifungal agents.     

Transformation of betulin diacetate by the Prins reaction

The interaction of betulin diacetate with formaldehyde by the Prins reaction in various media was studied. As a result, 3β,28-di-O-acetyl-30-hydroxymethyl-(20)29-lupene, 3β-acetyl-28-hydroxy-(20)29-lupene, and 3β,28-di-O-acetoxy-19-(5′,6′-dihydro-2′H-pyran-4′-yl)-20,29,30-trinorlupane were obtained.     

Highly enantioselective production of a chiral intermediate of sitagliptin by a novel isolate of <Emphasis Type="Italic">Pseudomonas pseudoalcaligenes</Emphasis>

Objective

To produce (S)-3-hydroxy-1-(3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-4-(2,4,5-trifluorophenyl)butan-1-one (S)-1 from 4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro [1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)-1-(2,4,5-trifluorophenyl)butan-2-one (2) by microbial bioreduction.

Results

A new isolate of Pseudomonas pseudoalcaligenes reduced enantioselectively prochiral ketone 2 to chiral alcohol (S)-1. Whole cells of the bacterium were tolerant towards 20 % (v/v) DMSO and 10 g 2/l. Under the optimal conditions, the preparative-scale bioreduction yielded (S)-1 at 90 % yield and >99 % ee. Cells could be re-used with the yield and ee of product being 45 % and >99 %, respectively, after five cycles.

Conclusion

Bioreduction using whole cells of P. pseudoalcaligenes is an attractive approach to produce (S)-1, as a chiral intermediate of the anti-diabetic drug, sitagliptin.

     

Synthesis of functionalized benzo[<Emphasis Type="Italic">f</Emphasis>]2<Emphasis Type="Italic">H</Emphasis>-chromenes and evaluation of their antimicrobial activities

Knoevenagel cyclocondensations of α-hydroxy naphthaldehyde with β-oxodithioesters and ketene dithioacetals yielded 2H-benzo[f]chromene-2-thiones and 2H-benzo[f]chromen-2-ones, respectively, in high yields. The newly synthesized compounds were evaluated for antifungal and antibacterial activities. Among them, compounds (2-furyl)(3-thioxo-3H-benzo[f]chromen-2-yl)methanone and phenyl(3-oxo-3H-benzo[f]chromen-2-yl)methanone exhibited excellent antifungal activity against tested fungi Curvularia lunata and Fusarium moniliforme. The highest antibacterial activity against the tested bacteria Escherichia coli and Staphylococcus aureus was observed for (4-chlorophenyl)(3-oxo-3H-benzo[f]chromen-2-yl)methanone. The results of antimicrobial screening demonstrate that (2-furyl)(3-thioxo-3H-benzo[f]chromen-2-yl)methanone, phenyl(3-oxo-3H-benzo[f]chromen-2-yl)methanone, and (4-chlorophenyl)(3-oxo-3H-benzo[f]chromen-2-yl)methanone are promising as antimicrobial drugs.     

Antimicrobial activities of some novel thiazoles

2-(4-Phenylthiazol-2(3H)-ylidene)-malononitrile was synthesized by treating 1-phenyl-2-thiocyanatoethanone with malononitrile. Reaction of 2-(4-phenylthiazol-2(3H)-ylidene)-malononitrile with hydrazine hydrate afforded 4-(4-phenylthiazol-2-yl)-1H-pyrazole-3,5-diamine, reaction with benzylidenemalononitrile yielded 2-(5-benzylidene-4-phenyl-5H-thiazol-2-ylidene)-malononitrile, and coupling with benzenediazonium chloride gave 2-(4-phenyl-5-phenylazo-3H-thiazol-2-ylidene)-malononitrile. Diaminopyrazole reacted with enaminonitrile to yield the 3-(4-phenylthiazol-2-yl)pyrazolo[1,5-a]pyrimidine-2,7-diamine. All synthesized compounds showed significant antimicrobial activities with MIC range of 5–750 µg/mL. The results demonstrated a correlation of the hydrophobicity of the compounds with their antimicrobial activity. The most potent antimicrobial compound was 2-(4-phenylthiazol-2(3H)-ylidene)-malononitrile.     

Antimicrobial activities of some synthesized 1-(3-(2-methylphenyl)-4-Oxo-3<Emphasis Type="Italic">H</Emphasis>-quinazolin-2-yl-4-(substituted)thiosemicarbazide derivatives

The substituted thiosemicarbazide moiety was placed at the C-2 position and 2-methylphenyl group at N-3 position of quinazoline ring and obtained compounds were tested for their antitubercular activities and antibacterial activities against selected gram-positive and gram-negative bacteria. The target compounds 1-(3-(2-methylphenyl)-4-oxo-3H-quinazolin-2-yl)-4-(substituted) thiosemicarbazides were obtained by the reaction of 2-hydrazino-3-(2-methylphenyl) quinazolin-4(3H)-one with different dithiocarbamic acid methyl ester derivatives. All synthesized compounds were also screened for their antimicrobial activity against selective gram-positive and gram-negative bacteria by agar dilution method. Among the series, 1-[3-(2-methylphenyl)-4-oxo-3H-quinazolin-2-yl]-4-[4-chlorophenyl]-thiosemicarbazide exhibited the most potent activity against S. typhi, E. coli, and B. subtilis, while 1-[3-(2-methylphenyl)-4-oxo-3H-quinazolin-2-yl]-4-[4-nitrophenyl]-thiosemicarbazide was the most potent against E. coli, B. subtilis, P. aeruginosa, S. typhi, and S. flexneri. These two compounds exhibited the antitubercular activity at the minimum concentration (3 μg/mL) that offered potential for further optimization and development of new antitubercular agents. The obtained results demonstrated promising antimicrobial and antitubercular activities of the synthesized quinazoline compounds which could be used as new scaffolds for improving their antimicrobial activity.     

2-(chromon-3-yl)imidazole derivatives as potential antimicrobial agents: synthesis,biological evaluation and molecular docking studies

A series of novel 2-(chromon-3-yl)-4,5-diphenyl-1H-imidazoles (4a-h) were synthesized by one pot condensation of substituted 3-formylchromones (1a-h), benzil (2) and ammonium acetate (3) in refluxing acetic acid at 110 °C under N2 atmosphere. Allylation of compounds 4a-h with allyl bromide in the presence of fused K₂CO₃ furnished N-allyl-2-(chromon-3-yl)-4,5-diphenyl-1H-imidazoles (6a-h). The synthesized compounds were characterized spectroscopically and evaluated for in vitro antimicrobial activity against various pathogenic bacterial and fungal strains by disc diffusion method. Compounds bearing electron withdrawing substituents such as bromo (4f) showed significant inhibitory activity against S. cerevisiae (MIC 1.4 μg/ml) and 4g containing chloro substituent, displayed more inhibitory potential against C. albicans (MIC 1.5), as compared to the standard drugs. Compounds 6a and 4c exhibit remarkable inhibitory potential against B. subtilis with MIC 0.98 and 1.23, respectively. The time kill assay for active compound 6a was performed by viable cell count (VCC) method to elucidate the microbicidal nature of 2-(chromon-3-yl)imidazoles. A molecular docking study of most active compounds with target ‘lanosterol 14α-demethylase’ (CYP51) was performed to unravel the mode of antifungal action.     

Oligoclonal expansion of TCR <Emphasis Type="Italic">V</Emphasis>δ T cells may be a potential immune biomarker for clinical outcome of acute myeloid leukemia

Background

Recent data have shown that γδ T cells can act as mediators for immune defense against tumors. Our previous study has demonstrated that persisting clonally expanded TRDV4 T cells might be relatively beneficial for the outcome of patients with T cell acute lymphoblastic leukemia after hematopoietic stem cell transplantation (HSCT). However, little is known about the distribution and clonality of the TRDV repertoire in T cell receptor (TCR) of γδ T cells and their effects on the clinical outcome of patients with acute myeloid leukemia (AML). The aim of this study was to assess whether the oligoclonal expansion of TCR Vδ T cells could be used as an immune biomarker for AML outcome.

Findings

γδ T cells were sorted from the peripheral blood of 30 patients with untreated AML and 12 healthy donors. The complementarity-determining region 3 (CDR3) sizes of eight TCR Vδ subfamily genes (TRDV1 to TRDV8) were analyzed in sorted γδ T cells using RT-PCR and GeneScan. The most frequently expressed TRDV subfamilies in the AML patients were TRDV8 (86.67 %) and TRDV2 (83.33 %), and the frequencies for TRDV1, TRDV3, TRDV4, and TRDV6 were significantly lower than those in healthy individuals. The most frequent clonally expanded TRDV subfamilies in the AML patients included TRDV8 (56.67 %) and TRDV4 (40 %). The clonal expansion frequencies of the TRDV2 and TRDV4 T cells were significantly higher than those in healthy individuals, whereas a significantly lower TRDV1 clonal expansion frequency was observed in those with AML. Moreover, the oligoclones of TRDV4 and TRDV8 were independent protective factors for complete remission. Furthermore, the oligoclonal expansion frequencies of TRDV5 and TRDV6 in patients with relapse were significantly higher than those in non-recurrent cases.

Conclusions

To the best of our knowledge, we characterized for the first time a significant alteration in the distribution and clonality of the TRDV subfamily members in γδ T cells sorted from AML patients. Clonally expanded TRDV4 and TRDV8 T cells might contribute to the immune response directed against AML, while oligoclonal TRDV5 and TRDV6 might occur in patients who undergo relapse. While the function of such γδ T cell clones requires further investigation, TRDV γδ T cell clones might be potential immune biomarkers for AML outcome.

     

Steroid compounds from the Far East starfish <Emphasis Type="Italic">Pteraster obscurus</Emphasis> and the ophiura <Emphasis Type="Italic">Asteronyx loveni</Emphasis>

Seven sulfated polyhydroxysteroids were isolated from the Far East starfish Pteraster obscurus and the ophiura (snake star) Asteronyx loveni (collected in the Sea of Okhotsk) and characterized: disodium and sodium salts of (20R)-24-methyl-2β-hydroxycholesta-5,24(28)-diene-3α,21-diyl disulfate, (20R)-5α-cholestane-3β,21-diyl disulfate, (20R)-3β-hydroxy-5α-cholestan-21-yl sulfate, (20R)-cholest-5-ene-3β,21-diyl disulfate, (20R)-2β-hydroxycholest-5-ene-3α,21-diyl disulfate, (20R)-cholest-5-en-3β-yl sulfate, and (20R)-5α-cholestan-3β-yl sulfate. The first four compounds turned out to be new, whereas the others were identical to the known compounds. Structures of the isolated steroids were identified by two-dimensional NMR spectroscopy and other physicochemical methods. The compounds isolated from starfish are structurally similar to typical ophiuroid metabolites, which support the opinion of some taxonomists that starfish and ophiuroids are phylogenetically related classes.     

Synthesis of some new <Emphasis Type="Italic">N</Emphasis>-substituted-<Emphasis Type="Italic">N</Emphasis>-(2,3-Dihydro-[1,4]benzodioxin-6-yl)-4-acetamidobenzenesulfonamides as valuable antibacterial agents

The aim of the research was to investigate the anti-bacterial potential of some N-substituted sulfonamides bearing benzodioxane moiety. The synthesis was started by reaction of N-2,3-dihydrobenzo[1,4]dioxin-6-amine with 4-acetamidobenzene-1-sulfonyl chloride in the presence of 10% aqueous Na₂CO₃ solution to yield N-(2,3-dihydrobenzo[1,4]-dioxin-6-yl)-4-acetamidobenzenesulfonamide, which was further reacted with alkyl/aralkyl halides in DMF and lithium hydride as a base to afford N-substituted-N-(2,3dihydro-[1,4]-benzodioxin-6-yl)-4-acetamidobenzenesulfonamides. All the synthesized compounds were characterized by spectral data (IR, ¹H NMR, EI-MS, and HR-MS). The compounds were tested for antibacterial activity and most of them exhibited potent therapeutic potential against various Gram-negative and Gram-positive strains.     

Synthesis and Protective Activity of β-Glycosides of <Emphasis Type="Italic">N</Emphasis>-Acetylmuramyl-<Emphasis Type="Italic">L</Emphasis>-Alanyl-<Emphasis Type="Italic">D</Emphasis>-Isoglutamine with Alkylalicyclic and Arylaliphatic Aglycons

The following glycosides of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) were synthesized: β-4-tert-butylcyclohexyl MDP, β-2-(adamant-1-yl)ethyl MDP, β-2,2-diphenylethyl MDP, and β-2-(p-biphenyl) ethyl MDP. The starting peracetylated β-N-acetylglucosaminides were prepared by the oxazoline method. They were converted into 4,6-O-isopropylidene-N-acetyl-D-muramic acids, which were coupled with L-Ala-D-Glu(NH₂)OBn. The target glycopeptides were obtained after their deprotection. The stimulation of the anti-infection resistance of mice against Staphylococcus aureus by the MDP glycosides was studied.     

Molecular complexes of ivy triterpene glycosides with β-cyclodextrin

Molecular complexes of triterpene glycosides such as α-hederin (hederagenin 3-O-α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranoside) and hederasaponin C (hederagenin 3-O-α-L-rhamnopyranosyl-(1 → 2)-O-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1 → 4)-O-β-D-glucopyranosyl-(1 → 6)-O-β-D-glucopyranoside) with β-cyclodextrin were synthesized. The complex formation was studied by FTIR spectroscopy. Toxic properties of the molecular complexes were examined.     

A new 2-(4<Emphasis Type="Italic">H</Emphasis>-1,3-benzoxazin-4-on-2-yl)-1,3-tropolone: Synthesis,structure, and antibacterial properties

2-(4H-1,3-Benzoxazin-4-on-2-yl)-4,5,6-trichloro-1,3-tropolone, structural properties of which were studied using ¹H NMR, IR-spectroscopy, mass spectrometry, and quantum chemistry has been obtained for the first time using an acid-catalyzed condensation reaction of 3,4,5,6-tetrachloro-1,2-benzoquinone with 2-methyl-4H-3,1-benzoxazin-4-one. It has been shown that the new tropolone possesses antibacterial activity against hospital-acquired strains of gram-negative (Escherichia coli, Salmonella enterica sv. Enteritidis, Acinetobacter baumannii, and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. The obtained substance is suggested for development of a new antibacterial drug.     

Chromosome number variability in central european members of the<Emphasis Type="Italic">Festuca ovina</Emphasis> and<Emphasis Type="Italic">F. pallens</Emphasis> groups (sect.<Emphasis Type="Italic">Festuca</Emphasis>)

Chromosome numbers for 98 plants ofF. pallens, 19 ofF. psammophila, F. belensis andF. vaginata, and 44 ofF. ovina (originating from Austria, the Czech Republic, Germany, Slovakia and Latvia) are given. In addition to theF. ovina andF. pallens groups, chromosome counts for the following taxa are also reported:F. alpestris (2n=14) reported for the first time in this work,F. amethystina subsp.amethystina (2n=28),F. brevipila (2n=42),F. cinerea (2n=28),F. rupicola subsp.rupicola (2n=42) andF. versicolor subsp.versicolor (2n=14).InF. pallens, two ploidy levels (2n=2x=14+0-1B, 2n=4x=28+0-1B) as well as two natural triploid plants (2n=21+0-1B), were found. In addition to the fourF. pallens types that have been distinguished in Austria, one new tetraploid type (F. pallens “scabrifolia”) from the Czech Republic and Germany is reported and its taxonomy is discussed. The distributions of the Oberösterreich-Niederösterreich and Pannonisches-HügellandF. pallens types outside of Austria are documented.Only the diploid chromosome number (2n=14) was found inF. psammophila andF. vaginata. Chromosome numbers forF. psammophila subsp.muellerstollii andF. belensis (both 2n=14) were determined here for the first time. Two ploidy levels, 2n=14+0-5B corresponding toF. ovina subsp.ovina and 2n=28 corresponding toF. ovina subsp.guestphalica andF. cf.duernsteinensis were confirmed inF. ovina. Differences in chromosome structure (simple and multiple secondary constrictions) betweenF. pallens as opposed toF. psammophila andF. vaginata are discussed. A complete survey of published chromosome counts for Central European species from theF. ovina andF. pallens groups is included.     

Induction of cellular immunity interleukin-12, antiproliferative effect,and related probiotic properties of lactic acid bacteria isolated in Thailand

Lactic acid bacteria (LAB) are widely known as probiotic microorganisms that afford several health benefits for the host. In this study, 15 isolates of LAB from various sources in Thailand were examined for their probiotic properties. Based on their phenotypic and genetic characteristics, they belong to the genera Lactobacillus, Pediococcus, and Weissella. All isolates showed the ability to induce interleukin-12 (IL-12) at different levels. Cell-free supernatant of Lactobacillus acidipiscis SR7-1 and Lactobacillus farraginis SL4-1 showed an antiproliferative effect against Caco-2 cell lines with non-toxicity to normal cell lines (Vero cells), while they had no effect against U937 cell lines. Five strains, including Lactobacillus namurensis KC78-5, L. farraginis SL4-1, Lactobacillus mucosae SL7-2, Lactobacillus salivarius MSMC120-2 and Pediococcus pentosaceus PC73-3 grew at pH 3. All isolates were tolerant at 1% bile. L. farraginis SL4-1, L. mucosae SL7-2 and P. pentosaceus PC73-3 were not statistically different when compared to the negative control in vitro adhesion assay. These results suggest that L. farraginis SL4-1, L. mucosae SL7-2 and P. pentosaceus PC73-3, which meet the general criteria of probiotics, represent very interesting candidates for further study as anti-cancer agents, especially L. farraginis SL4-1, which has an antiproliferative effect against Caco-2 cells and immunomodulatory ability. These results also highlight the need for further study, especially in appropriate in vivo animal models.     

Design and synthesis of an indol derivative as antibacterial agent against <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

Several indole derivatives with antibacterial activity have been prepared using different protocols; however, some require special reagents and conditions. The aim of this study involved the synthesis of some indole derivatives using estrone and OTBS-estrone as chemical tools. The synthesis of the indole derivatives involves reactions such as follows: (1) synthesis of two indol derivatives (4 or 5) by reaction of estrone or OTBS-estrone with phenylhydrazine in medium acid; (2) reaction of 4 or 5 with 6-cloro-1-hexyne in medium basic to form two hexynyl-indol (7 or 8); (3) preparation of indol-propargylic alcohol derivatives (10 or 11) by reaction of benzaldehyde with 7 or 8 in medium basic; (4) synthesis of indol-aldehydes (12 or 13) via oxidation of 10 or 11 with DMSO; (5) synthesis of indeno-indol-carbaldehyde (15 or 16) via alkynylation/cyclization of 12 or 13 with hexyne in presence of copper(II); (6) preparation indeno-indol-carbaldehyde complex (19 or 20) via alkynylation/cyclization of 12 or 13 with 1-(hex-5-yn-1-yl)-2-phenyl-1H-imidazole. The antibacterial effect exerted by the indol-steroid derivatives against Streptococcus pneumoniae and Staphylococcus aureus bacteria was evaluated using dilution method and the minimum inhibitory concentration (MIC). The results showed that only the compound 19 inhibit the growth bacterial of S. aureus. In conclusion, these data indicate that antibacterial activity of 19 can be due mainly to functional groups involved in the chemical structure in comparison with the compounds studied.     

Chemo-enzymatic synthesis of a glycosylated peptide containing a complex <Emphasis Type="Italic">N</Emphasis>-glycan based on unprotected oligosaccharides by using DMT-MM and Endo-M

For chemo-enzymatic synthesis of a glycosylated peptide, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) was used for the synthesis of a N-acetylglucosaminyl peptide and a pseudoglycopeptide by solid-phase peptide synthesis without the requirement of protecting groups on the carbohydrate. We also performed transglycosylation of an N-glycan to the N-acetylglucosaminyl peptide using endo-β-N-acetylglucosaminidase from Mucor hiemalis (Endo-M) to synthesize a glycopeptide containing a complex N-glycan.     

Downregulation of expression of mater genes <Emphasis Type="Italic">SOX9, FOXA2</Emphasis>, and <Emphasis Type="Italic">GATA4</Emphasis> in pancreatic cancer cells stimulated with TGFβ1 epithelial–mesenchymal transition

We show characteristic morphological changes corresponding to epithelial–mesenchymal transition (EMT) program fulfillment in PANC1 cell line stimulated with TGFβ1. Our results support downregulation of E-cadherin protein. We show 5- and 28-fold increase in SNAI1 and SNAI2 expression levels and 25- and 15-fold decrease in CDH1 and KRT8 expression levels, respectively, which confirms the EMT-program fulfillment. We demonstrate downregulation of expression of pancreatic master genes SOX9, FOXA2, and GATA4 (2-, 5-, and 4-fold, respectively) and absence of significant changes in HES1, NR5A2, and GATA6 expression levels in the cells stimulated with TGFβ1. Our results indicate the absence of induction of expression of PTF1A, PDX1, HNF1b, NEUROG3, RPBJL, NKX6.1, and ONECUT1 genes, which are inactive in PANC1 cell line after the EMT stimulated by TGFβ1.     

Karyotypic study of five Lutjanid species using conventional and Ag-NORs banding techniques

The first cytogenetic comparisons of five snapper species from Thailand were presented here. Renal cell samples were taken from blacktail snapper (Lutjanus fulvus), five lined snapper (L. quinquelineatus), dory snapper (L. fulviflamma), brownstripe red snapper (L. vitta), and mangrove red snapper (L. argentimaculatus). The mitotic chromosome preparation was prepared directly from kidney cells. Conventional staining and Ag-NOR banding techniques were applied to stain the chromosomes. The results exhibited that all five snapper species have the diploid chromosome numbers of 2n = 48 and the fundamental numbers (NF) of 48. The presences of large, medium, and small telocentric chromosomes were 22-24-2, 24-20-4, 36-10-2, 28-16-4 and 36-10-2, respectively. The Ag- NORs banding technique provides the pair of nucleolar organizer regions (NORs) at subcentromeric region of the long arm of the respective telocentric chromosome pairs 9, 1, 3, 4 and 9. Their karyotype formulas is as follows: L. fulvus (2n = 48): L ₂₂ ^t + M ₂₄ ^t + S ₂ ^t , L. quinquelineatus (2n = 48): L ₂₄ ^t + M ₂₀ ^t + S ₄ ^t , L. fulviflamma (2n = 48): Lt36 + Mt10 + St2, L. vitta (2n = 48): L ₂₈ ^t + M ₁₆ ^t + S ₄ ^t , and L. argentimaculatus (2n = 48): L ₃₆ ^t + M ₁₀ ^t + S ₂ ^t .     

Genetic Collection of Meiotic Mutants of Rye <Emphasis Type="Italic">Secale cereale</Emphasis> L.

Genetic collection of meiotic mutants of winter rye Secale cereale L. (2n = 14) was created. Mutations were detected in inbred F₂ generations after self-fertilization of the F₁ hybrids, obtained by individual crossing of rye plants (cultivar Vyatka) or weedy rye with plants from autofertile lines. The mutations cause partial or complete plant sterility and are maintained in collection in a heterozygous state. Genetic analysis accompanied by cytogenetic study of meiosis has revealed six mutation types. (1) Nonallelic asynaptic mutations sy1 and sy9 caused the formation of only axial chromosome elements in prophase and anaphase. The synaptonemal complexes (SCs) were absent, the formation of the chromosome “bouquet” was impaired, and all chromosomes were univalent in meiotic metaphase I in 96.8% (sy1) and 67% (sy2) of cells. (2) Weak asynaptic mutation sy3, which hindered complete termination of synapsis in prophase I. Subterminal asynaptic segments were always observed in the SC, and at least one pair of univalents was present in metaphase I, but the number of cells with 14 univalents did not exceed 2%. (3) Mutations sy2, sy6, sy7, sy8, sy10, and sy19, which caused partially nonhomologous synapsis: change in pairing partners and fold-back chromosome synapsis in prophase I. In metaphase I, the number of univalents varied and multivalents were observed. (4) Mutation mei6, which causes the formation of ultrastructural protrusions on the lateral SC elements, gaps and branching of these elements. (5) Allelic mutations mei8 and mei8-10, which caused irregular chromatin condensation along chromosomes in prophase I, sticking and fragmentation of chromosomes in metaphase I. (6) Allelic mutations mei5 and mei10, which caused chromosome hypercondensation, defects of the division spindle formation, and random arrest of cells at different meiotic stages. However, these mutations did not affect the formation of microspore envelopes even around the cells, whose development was blocked at prophase I. Analysis of cytological pictures of meiosis in double rye mutants reveled epistatic interaction in the mutation series sy9 > sy1 > sy3 > sy19, which reflects the order of switching these genes in the course of meiosis. The expression of genes sy2 and sy19 was shown to be controlled by modifier genes. Most meiotic mutations found in rye have analogs in other plant species.