Inheritance Profile of Weathered Chlordane and P,P′-DDTs Accumulation by cucurbita pepo hybrids

Cucurbita pepo ssp pepo (zucchini) accumulates significant levels of persistent organic pollutants in its roots, followed by unexpectedly high contaminant translocation to the stems. Most other plant species, including the closely related C. pepo ssp ovifera (squash), do not have this ability. To investigate the mechanism of contaminant accumulation, two cultivars each of parental zucchini and squash, as well as previously created first filial (F1) hybrids and F1 backcrosses (BC) of those parental cultivars, were grown under field conditions in a soil contaminated with weathered chlordane (2.29 μg/g) and DDX residues (0.30 μg/g; sum of DDT, DDE, DDD). The parental zucchini had stem-to-soil bioconcentration factors (BCF, contaminant ratio of stem to soil) for chlordane and DDX of 6.23 and 3.10; these values were 2.2 and 3.7 times greater than the squash, respectively. Chlordane and DDX translocation factors, the ratio of contaminant content in the stems to that in the root, were 2.1 and 3.2 times greater for zucchini than for squash. The parental zucchini and squash also differed significantly in chlordane component ratios (relative amounts of trans-nonachlor [TN], cis-chlordane [CC], trans-chlordane [TC]) and enantiomer fractions for the chiral CC and TC. Hybridization of the parental squash and zucchini resulted in significant differences in contaminant uptake. For both the three separate component ratios (CR) and two sets of enantiomer fraction (EF) values, subspecies specific differences in the parental generation became statistically equivalent in the F1 hybrid zucchini and squash. When backcrossed (BC) with the original parental plants, the zucchini and squash F1 BC cultivars reverted to the statistically distinct CR and EF patterns. This pattern of trait segregation upon hybridization suggests either single gene or single locus control for persistent organic pollutant (POP) uptake ability by C. pepo ssp pepo.     

Synthesis and Evaluation of Oligonucleotide-Conjugated Pyrrole Polyamide-2′-Deoxyguanosine Hybrids as Novel Gene Expression Control Compounds

DNA oligonucleotide-conjugated pyrrole polyamide-2′-deoxyguanosine hybrids were synthesized and examined as novel gene expression control compounds. The T_m values and circular dichroism spectral analyses showed that the oligonucleotide-conjugated hybrids possess high DNA recognition and a very high binding affinity for DNA that includes the pyrrole polyamide binding sequence.     

Synthesis,DNA-Binding,and Photocleavage Properties of a Serious of Porphyrin-Daunomycin Hybrids

It is widely accepted that the pharmacological activities of anthracyclines antitumor agents express when the quinone-containing chromophore intercalates into base pairs of the duplex DNA. We have successfully synthesized and investigated the DNA-interactions of hybrids composed with quinone chromophore and cationic porphyrin. Herein, a clinic anticancer drug, daunomycin, is introduced to the porphyrin hybrids through different lengths of amide alkyl linkages, and their interactions and cleavage to DNA were studied compared with the previous porphyrin-quinone hybrids. Spectral results and the determined binding affinity constants (K_b) show that the attachment of daunomycin to porphyrin could improve the DNA-binding and photocleaving abilities. The porphyrin-daunomycin hybrids may find useful employment in investigating the ligand-DNA interaction.     

In-Silico molecular docking and simulation studies on novel chalcone and flavone hybrid derivatives with 1, 2, 3-triazole linkage as vital inhibitors of Plasmodium falciparum dihydroorotate dehydrogenase

The structural motifs of chalcones, flavones, and triazoles with varied substitutions have been studied for the antimalarial activity. In this study, 25 novel derivatives of chalcone and flavone hybrid derivatives with 1, 2, 3-triazole linkage are docked with Plasmodium falciparum dihydroorotate dehydrogenase to establish their inhibitory activity against Plasmodium falciparum. The best binding conformation of the ligands at the catalytic site of dihydroorotate dehydrogenase are selected to characterize the best bound ligand using the best consensus score and the number of hydrogen bond interactions. The ligand namely (2E)-3-(4-{[1-(3-chloro-4-fluorophenyl)-1H-1, 2, 3-triazol-4-yl]methoxy}-3-methoxyphenyl-1-(2-hydroxy-4,6-dimethoxyphenyl)prop-2-en-1-one, is one the among the five best docked ligands, which interacts with the protein through nine hydrogen bonds and with a consensus score of five. To refine and confirm the docking study results, the stability of complexes is verified using Molecular Dynamics Simulations, Molecular Mechanics /Poisson–Boltzmann Surface Area free binding energy analysis, and per residue contribution for the binding energy. The study implies that the best docked Plasmodium falciparum dihydroorotate dehydrogenase–ligand complex is having high negative binding energy, most stable, compact, and rigid with nine hydrogen bonds. The study provides insight for the optimization of chalcone and flavone hybrids with 1, 2, 3-triazole linkage as potent inhibitors.     

Self‐selection of photoperiod as a technique for studying endogenous rhythms in fish

Abstract

Drawing on work with passerine birds, investigations on the self‐selection of photoperiod in a constant environment by pumpkinseed sunfish (Lepomis gibbosus) capable of controlling their lighting have been carried out. Each aquarium with lighting equipment was set up in a separate, light‐tight compartment in a quiet, constant‐temperature room. Under one treatment, an overhead fluorescent light could be turned on and off by breaking a photobeam. Under two further treatments, breaking the photobeam turned the light on for three minutes. Fish were fed daily at a regular hour. The latter two treatments, but not the first, resulted in data containing diurnal rhythmic components as analyzed by autocorrelation techniques. The results are discussed in the context of different methods of measuring “internal clock” mechanisms.     

Synthesis and biological evaluation of berberine–thiophenyl hybrids as multi-functional agents: Inhibition of acetylcholinesterase,butyrylcholinesterase, and Aβ aggregation and antioxidant activity

A series of berberine–thiophenyl hybrids were designed, synthesised, and evaluated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and β-amyloid (Aβ) aggregation and as antioxidants. Among these hybrids, compounds 4f and 4i, berberine linked with o-methylthiophenyl and o-chlorothiophenyl by a 2-carbon spacer, were observed to be potent inhibitors of AChE, with IC₅₀ values of 0.077 and 0.042 μM, respectively. Of the tested compounds, 4i was also the most potent inhibitor of BuChE, with an IC₅₀ value of 0.662 μM. Kinetic studies and molecular modelling simulations of the AChE-inhibitor complex indicated that a mixed-competitive binding mode existed for these berberine derivatives. The biological studies also demonstrated that these hybrids displayed interesting activities, including Aβ aggregation inhibition and antioxidant properties.     

Characterization of the genome of <Emphasis Type="Italic">Saccharomyces</Emphasis> yeasts from red berry wines

Using restriction analysis of noncoding rDNA regions, multiplex PCR, and molecular karyotyping, we have examined Saccharomyces strains isolated from red berry wine materials in Russia, Belarus, and Ukraine. According to the molecular analysis, all strains belong to the species S. cerevisiae. A correlation was revealed between microsatellite fingerprints of the strains and the source of their isolation. The strains isolated from juices and from the surface of different berries showed distinct PCR profiles. The genome compositions of interspecific Saccharomyces hybrids of natural and laboratory origin were studied.     

Fertility of females of sturgeon hybrids obtained from species with different levels of ploidy (Acipenser ruthenus and A. dauricus) and their cloning

Main purpose of this work is the identification of females of artificial sturgeon hybrids capable to produce unreduced oocytes. The importance of this task is due to the ability to receive clonal all-female lines. Experiments were performed on the previously obtained reciprocal hybrids of sterlet, Acipenser ruthenus (S) with ~120 chromosomes and kaluga, Acipenser dauricus (K) with ~260 chromosomes. Karyotypes of backcross hybrids of (S × K) female (obtained by crossing sterlet female with kaluga male) and sterlet male included 180 – 190 chromosomes. This means that (S × K) female produced eggs with ~125 chromosomes and its karyotype consisted of ~250 chromosomes. This number was confirmed by a comparative analysis of erythrocyte size in this female and species with different ploidy. Karyotype with ~250 chromosomes can occur in (S x K) female only as a result of fertilization of a diploid sterlet egg (120 chromosomes) with kaluga haploid sperm (~130 chromosomes). Eggs of hybrid fertile (S × K) female, inseminated with inactivated sperm of Amur sturgeon and sterlet, developed into viable gynogenetic offspring, confirmed by the analysis of five microsatellite loci in this progeny, (S x K) female, and males used for UV-inactivated sperm. These data allow us to propose a method for obtaining fertile females of sturgeon hybrids from species with different ploidy. For this, experimentally obtained diploidized eggs from diploid 120-chromosome species must be fertilized by 250–270-chromosome male. Karyotypes of backcross hybrids of (K × S) female (obtained by crossing kaluga female with sterlet male) and sterlet male included ~250 chromosomes and hybrids of this female with kaluga male had ~320 chromosomes. These results proved an ability of hybrid (K × S) female to produce unreduced eggs, resulting in triploid backcrosses. The absence of reduction during egg development is well known in clonal forms (species) of vertebrates, which are of hybrid origin, and in artificially created fish hybrids. However, this has not been reported previously for sturgeons. Insemination of eggs of (K × S) female with UV-inactivated sperm of sterlet and Amur sturgeon led to offspring generation for which the genetic identity to their mother was proved using microsatellite analysis. That is, clonal inheritance was observed. These results suggest the possibility of developing a technology to produce all-female offspring. Artificial production of clonal lines in hybrid vertebrates can be also considered as experimental reproduction of the first stages of reticular speciation in nature.     

Tempo and mode of recurrent polyploidization in the Carassius auratus species complex (Cypriniformes,Cyprinidae)

Polyploidization is an evolutionarily rare but important mechanism in both plants and animals because it increases genetic diversity. Goldfish of the Carassius auratus species complex can be tetraploids, hexaploids and octaploids. Polyploidization events have occurred repeatedly in goldfish, yet the extent of this phenomenon and its phyletic history are poorly understood. We explore the origin, tempo and frequency of polyploidization in Chinese and Japanese goldfish using both mitochondrial (mtDNA) and nuclear DNA sequences from up to 1202 individuals including the outgroup taxon, Cyprinus carpio. Analyses of de novo nuclear gene data resolve two clusters of alleles and the pattern supports the prior hypothesis of an ancient allotetraploidization for Carassius. Alleles shared by tetraploid and hexaploid individuals indicate recent autoploidizations within the C. auratus complex. Sympatric tetraploids and hexaploids share mtDNA haplotypes and these frequently occur independently within six well-supported lineages and sublineages on a small spatial scale. Gene flow estimates (F_st values) indicate that hexaploids differ only slightly from sympatric tetraploids, if at all. In contrast, allopatric populations of tetraploids and hexaploids differ from one another to a far greater extent. Gene flow between sampled localities appears to be limited. Coalescence-based time estimations for hexaploids reveal that the oldest lineage within any sampled locality is around one million years old, which is very young. Sympatric, recurrent autoploidization occurs in all sampled populations of the C. auratus complex. Goldfish experience polyploidization events more frequently than any other vertebrate.     

细菌中RNase HI介导RNA降解的研究进展

在细菌细胞中,为了维持基因组稳定和正常的生命活动,RNase HI通常以降解RNA/DNA杂合链中RNA的方式来防止复制中引物的积累以及转录中R环的形成。RNase HI对底物的识别主要依赖于DNA与RNA结合槽,对底物的催化主要依赖于DEDD基序和位于活性位点附近柔性环中的一个组氨酸。以Mg²⁺为代表的金属离子在催化过程中发挥了至关重要的作用。杂交双链中ssDNA突出部分的类型决定了RNase HI的作用模式：在没有突出或在ssDNA的5′端存在突出部分的情况下,RNase HI作为一种非序列特异性核酸内切酶随机地降解RNA;当ssDNA的3′端存在突出部分时,RNase HI依靠5′核酸外切酶活性对RNA进行连续切割。RNase HI、Rep、DinG和UvrD通过与单链DNA结合蛋白(single-stranded DNA-binding protein, SSB)的C端尾部的6个残基相互作用被招募到复制叉附近,并可能以协作的方式解决复制-转录冲突。RNaseHI的缺失或活性降低将引起DNA结构不稳定、基因突变、转录装置回溯和复制不协调等一系列有害后果。RN...