The role of nutrition on epigenetic modifications and their implications on health

Nutrition plays a key role in many aspects of health and dietary imbalances are major determinants of chronic diseases including cardiovascular disease, obesity, diabetes and cancer. Adequate nutrition is particularly essential during critical periods in early life (both pre- and postnatal). In this regard, there is extensive epidemiologic and experimental data showing that early sub-optimal nutrition can have health consequences several decades later.     

Ferulic acid–carbazole hybrid compounds: Combination of cholinesterase inhibition,antioxidant and neuroprotection as multifunctional anti-Alzheimer agents

In order to search for novel multifunctional anti-Alzheimer agents, a series of ferulic acid–carbazole hybrid compounds were designed and synthesized. Ellman’s assay revealed that the hybrid compounds showed moderate to potent inhibitory activity against the cholinesterases. Particularly, the AChE inhibition potency of compound 5k (IC₅₀ 1.9 μM) was even 5-fold higher than that of galantamine. In addition, the target compounds showed pronounced antioxidant ability and neuroprotective property, especially against the ROS-induced toxicity. Notably, the neuroprotective effect of 5k was obviously superior to that of the mixture of ferulic acid and carbazole, indicating the therapeutic effect of the hybrid compound is better than the combination administration of the corresponding mixture.     

Phylogenetic analyses of primate size evolution: the consequences of sexual selection

We have analysed the relationship between primate mating system, size and size dimorphism by utilizing several phylogenetically based methods. An independent contrast analysis of male and female size (log weight) showed that these are tightly correlated and that size dimorphism is not a simple allometric function of size. We found no relationship between mating system and sexual dimorphism in strepsirhines but a strong relationship in haplorhines. By matched-pairs analysis, where sister groups were matched according to whether the mating system predicted higher or lower intrasexual selection for male size, haplorhine species in more polygynous clades (with a predicted higher sexual selection) were significantly more dimorphic, had larger males, and also, but to a lesser degree, larger females. Both independent contrast and matched-pairs analyses are non-directional and correlational. By using a directional test we investigated how a transition in mating system affects size and dimorphism. Here, each observation is the sum of changes in dimorphism or size in a clade that is defined by a common origin of a mating system. Generally, dimorphism, as well as male and female size, increased after an expected increase in sexual selection, and decreased after an expected decrease in sexual selection. The pattern was, however, not significant for all of the alternative character reconstructions. In clades with an expected increase in sexual selection, male size increased more than female size. This pattern was significant for all character reconstructions. The directional investigation indicates that the magnitude of change in haplorhine dimorphism is larger after an increase in sexual selection than after a decrease, and, for some reconstructions, that the magnitude of size increase is larger than the magnitude of size decrease for both sexes. Possible reasons for these patterns are discussed, as well as their implications as being one possible mechanism behind Cope's rule, i.e. general size increase in many phylogenetic lineages.     

An inordinate fondness for beetles*

The abundance and diversity of insects was the subject of the joint commemorative meeting between the Linnean Society and the Royal Entomological Society of London. This paper gives a brief outline of the foundation and early history of the Entomological Society and its forerunners, and its relations with the Linnean Society at the time. It also shows how the contributions of the founding fellows of the Society, whose interests originated in collecting and insect natural history, laid the foundations of many of the present day fields of entomological research.     

Evidence for rapid limitation of the I element copy number in a genome submitted to several generations of I-R hybrid dysgenesis in Drosophila melanogaster

Summary When Drosophila melanogaster males coming from a class of strains known as inducer are crossed with females from the complementary class (reactive), a quite specific kind of sterility is observed in the F₁ female progeny (denoted SF). The inducer chromosomes differ from the reactive chromosomes by the presence of a transposable element (called the I factor) that is responsible for the induction of this dysgenic symptom. In the germ line of dysgenic females, up to 100% of the reactive chromosomes may be contaminated, i.e. they acquire I factor(s) owing to very frequent replicative transpositions. A contaminated reactive stock was obtained by reconstructing the reactive genotype in the offspring of SF females and its kinetics of invasion by I elements was followed in the successive inbred dysgenic generations. The results show that the mean copy number of I elements increased very quickly up to the level of inducer strains and then stayed in equilibrium even though the dysgenic state was perpetuated by selection for SF sterility at every generation. The possible mechanisms of this copy number limitation are discussed.     

Specificity of the interactions between the Rep proteins and the origins of replication of Staphylococcus aureus plasmids pT181 and pC221

Summary pT181 and pC221 are closely relatedStaphylococcus aureus plasmids with the same genome organization, which is characterized by the overlapping of the origin of replication with the sequence encoding a protein, Rep, essential for plasmid replication. Former results have shown the lack of in vivo cross-complementation between these two plasmids, while in vitro studies have revealed the ability of both Rep proteins to act on either origin. One possible explanation for this difference was based on a previous analysis of the incompatibility expressed by the origin of replication of these plasmids, showing that the origin embedded in therep gene competes for Rep utilization with the origin of a test plasmid and that changes in the sequence of the origin reduce its ability to compete. To avoid this problem, in the present work special hybrids were constructed in which the origin of replication overlapping therep gene was mutationally inactivated, without changing the amino acid sequence of the encoded protein. The level of Rep expression by these hybrids could be varied by taking advantage of what is presently known about the control of Rep synthesis in plasmid pT181. The results of complenentation studies conducted using these hybrids have shown that: (i) at the usual level of expression for a wild-type plasmid each Rep protein can initiate replication strictly from its corresponding origin; (ii) when overproduced, the pT181 RepC protein could also act efficiently on the pC221 origin; a functional pT181 origin present in the same host completely prevented this complementation; (iii) in excess, the RepD protein encoded by pC221 could replicate a plasmid carrying the pT181 origin but could not ensure the hereditary stability of such a plasmid in the absence of another active replication system; (iv) when overproduced both RepC and RepD could act on the origin of replication of three other related plasmids pS194, pC223 and pUB112.     

Inheritance of plastids in interspecific hybrids of blue spruce and white spruce

Summary Chloroplast DNA (cpDNA) was purified from blue spruce (Picea pungens Engelm.) and white spruce [P. glauca (Moench) Voss], and was digested with several different restriction endonucleases. Restriction fragment length polymorphisms (RFLPs) were identified that differentiated the cpDNA of both species. Intraspecific conservation of the RFLPs that differentiated each species was confirmed by examining trees from across the natural range of each species. Ten F₁ hybrids were examined, and the cpDNA from each showed the banding pattern of the paternal species. Cloned Petunia cpDNA containing part of the rbcL gene hybridized to polymorphic bands, while a cloned maize mtDNA probe of the coxII gene failed to hybridize to any band.     

Use of tissue culture to bypass wheat hybrid necrosis

Summary Hybrid necrosis in wheat is a barrier to gene transfer in wheat breeding practice. It is based on two complementary genes, Ne1 and Ne2. Recovery mutants (Re1, Re2 and Re3) which can grow to maturity were recovered from immature embryo cultures of necrotic hybrids between T. aestivum and T. durum. Cytological observation demonstrated that Re1 had 34 chromosomes instead of 35. This indicated that one of the chromosomes carrying the Ne genes was lost. Genetic study suggested that for Re1, the lost chromosome was chromosome 5B of the durum parental line. Re mutants are male sterile but can be maintained through a young ear culture method. Re mutants could be successfully pollinated by either parental line and the BC1 progeny is partially fertile. Re mutants were repeatedly induced in about 1% of the regenerated plants from immature embryo culture. This technique provides a practical way to bypass hybrid necrosis.     

Degradation of 3-chlorobiphenyl by in vivo constructed hybrid pseudomonads

Abstract 3-Chlorobiphenyl-degrading bacteria were obtained from the mating between Pseudomonas putida strain BN10 and Pseudomonas sp. strain B13. Strains such as BN210 resulted from the transfer of the genes coding the enzyme sequence for the degradation of chlorocatechols from B13 into BN10, whereas B13 derivatives such as B131 have acquired the biphenyl degradation sequence from BN10. During growth of the hybrid strains on 3-chlorobiphenyl 90% chloride was released. Activities of phenylcatechol 2,3-dioxygenase, benzoate dioxygenase, catechol 1,2-dioxygenase, chloromuconate cyloisomerase and 4-carboxymethyl-enebut-2-en-4-olide hydrolase were found in 3-chlorobiphenyl-grown cells. The hybrid strains were found to convert some congeners of the Aroclor 1221 mixture such as mono- and dichloro-substituted biphenyls.