Evaluation and validation of candidate endogenous control genes for real-time quantitative PCR studies of breast cancer

Background  

Real-time quantitative PCR (RQ-PCR) forms the basis of many breast cancer biomarker studies and novel prognostic assays, paving the way towards personalised cancer treatments. Normalisation of relative RQ-PCR data is required to control for non-biological variation introduced during sample preparation. Endogenous control (EC) genes, used in this context, should ideally be expressed constitutively and uniformly across treatments in all test samples. Despite widespread recognition that the accuracy of the normalised data is largely dependent on the reliability of the EC, there are no reports of the systematic validation of genes commonly used for this purpose in the analysis of gene expression by RQ-PCR in primary breast cancer tissues. The aim of this study was to identify the most suitable endogenous control genes for RQ-PCR analysis of primary breast tissue from a panel of eleven candidates in current use. Oestrogen receptor alpha (ESR1) was used a target gene to compare the effect of choice of EC on the estimate of gene quantity.     

Structure and Dynamics of the Arboreal Termite Community in New Guinean Coconut Plantations21

Whereas ant mosaics have been widely recognized and described in tropical ecosystems, data on space partitioning among arboreal termite colonies are rudimentary. During a long term field study in New Guinea, the distribution of arboreal termite species in coconut plantations as well as the extent and dynamics of competition between them were investigated. The three dominant species, Mirrocerotermes biroi, Nasutitermes princeps and N. novarumhebridarum, feed on the same items but never exploit the same tree. The resulting distribution pattern is a mosaic with two peculiarities. First, some extended areas around N. princeps colonies appear unexploited, as this species practices interference competition on a wide scale, defending large territories inter- and intra-specifically. Second, interspecific relations are asymmetrical. In some plantations, large colonies of N. princeps expand their territory by destroying colonies of M. biroi, but when the pressure of N. princeps is relaxed, dense populations of colonies of M. biroi can recolonize the trees in a few years’ time. Territorial boundaries may thus change relatively fast. N. novarumhebridarum often colonizes dead trees and interferes less with the other species. These facts are consistent with each species’ reproductive investment strategy. Hypotheses are proposed to explain how the dominant species can coexist, even in long established plantations.     

Change in termite communities along a chronosequence of mango tree orchards in the north of Côte d’Ivoire

Termites constitute the major component of the macrofauna of the soil, and influence the structure of the soil, in tropical regions. This study aimed to estimate their assemblages in a chronosequence of mango tree orchards in the north of Côte d’Ivoire and compare them with those in unmanaged savanna. Using a standardized method of rapid biodiversity estimation, termites were collected in seven age classes of mango tree orchards (class 1: <5 years; class 2: 5–9 years; class 3: 10–14 years; class 4: 15–19 years; class 5: 20–24 years; class 6: 25–29 years; class 7: 30 years and over) and compared with termites collected from the savanna. Results show that the species richness was lowest in the young orchards of class 1 (9 species), and increased with the age of the orchards to reach its maximum in the old orchards of class 7 (28 species); these latter were comparable in richness with the savanna (26 species). The Shannon index (H’) and the evenness (E) follow the same trend as the species richness. The orchards of classes 1 and 2 were more dissimilar to the savanna. In contrast, termites were well represented in the savanna and in the old orchard of classes 6 and 7. Rhinotermitinae and Cubitermitinae subfamilies, absent in the young orchards of classes 1 and 2, were very abundant in the old orchards (classes 6 and 7). Overall, the findings of this study show that only the old mango orchards sustain termite diversity that comes close to that of the savanna. In this region, the cessation of agricultural activities in mango orchards favors the reconstitution of termite communities and presumably the restoration of the ecosystem services provided by termites. Thus it would be possible to combine agriculture and the conservation soil biodiversity.     

Differentiation of worker-derived intercastes and precocious imagoes after queen removal in the Neo-Guinean termite Nasutitermes princeps (Desneux)

Numerous female workers underwent a beginning of sexualization in an experimentally orphaned colony of the Neo-Guinean termite N. princeps (Desneux). This led to the development of intercastes, displaying variable mosaics of worker, nymph, and soldier characteristics. The developmental pathways of these intercastes were studied with the help of multivariate techniques that revealed two main lines, one ending in a new “giant soldier” morph, the other proceeding toward the differentiation of nymphal characters, i.e., wing pads and compound eyes. It is not known whether these individuals might ultimately have become functional. Precocious adults resulting from a shortened nymphal course were also present, and one young replacement queen had already begun laying eggs.     

The potential exploitation of plant viral translational enhancers in biotechnology for increased gene expression

The regulation of gene expression is extremely important for all organisms, not least for viruses that require a maximum rate of production of viral proteins to allow rapid multiplication and spread. Singlestranded positive-sense RNA viruses contain specific nucleotide sequences that can be used to elevate the expression of vital gene products to required high levels. Among plant viruses, translational enhancement has been documented widely, especially over the past few years. Reported candidates include one of the best known and most intensely researched virus, tobacco mosaic virus, members of the potyvirus group, and even a small satellite RNA of tobacco necrosis virus. Enhancement values range from 2–100-fold with different viruses, different reporter genes, and in different systems. Research indicates that an absence of secondary structure alone does not explain translational enhancement and despite attempts to determine the mechanism by which this enhancement occurs very little conclusions can be made as yet. Whatever the mechanism, the presence of these sequences upstream from an open reading frame results in an elevated level of protein production and may feature as important tools for biotechnology in the future.