Is there gold at the top of the beanstalk?

A report on the 3rd International Legume Genetics and Genomics Conference, Brisbane, Australia, 9-13 April 2006.     

Room at the top? Minority mobility and the transition to demographic diversity in the USA

We examine the ramifications of the demographic transition to diversity in the USA through an analysis of changes at the top of the occupational hierarchy, as glimpsed in recent census data. We find evidence that, among the incumbents of better-paid occupations, the percentage of non-Hispanic whites, the historically dominant majority, is sharply declining, while the proportion of immigrant-origin minorities, Asians, both foreign and US born, and US-born Hispanics, is growing. African Americans, or US-born blacks, are not so far sharing much in this growth. However, whites still retain important advantages in terms of occupational placement net of education and in terms of earnings net of occupational placement. We conclude overall that demographic shifts are highly likely to drive further diversification at the top of the US workforce; the question of whether whites can hold on to their advantages in the face of these changes cannot be answered yet.     

‘Recognition units’ at the top of a neuronal hierarchy?

The electric fish, Eigenmannia, is able to discriminate the sign of the frequency difference, Df, between a neighbor's electric organ discharges (EODs) and its own. The fish lowers its EOD frequency for positive Dfs and raises its frequency for negative Dfs to minimize jamming of its electrolocation ability by a neighbor's EODs of similar frequency. This jamming avoidance response (JAR) is controlled by a group of 'sign-selective' neurons in the prepacemaker nucleus (PPN) that is located at the boundary of the midbrain and the diencephalon (Fig. 1). Extracellular recordings from a total of 35 neurons revealed a great similarity between behavioral and neuronal response properties: 1. All neurons fired vigorously for negative Dfs and were almost silent for positive Dfs, regardless of the orientation of the jamming stimulus, and thus discriminated the sign of Df unambiguously (Fig. 2). 2. In accordance with behavioral observations, individual neurons failed to discriminate the sign of Df when the jamming stimulus had the same field geometry as the signal mimicking the animal's own EOD (Fig. 3). 3. Df magnitudes which evoke strongest JARs, usually 4 to 8 Hz, also induced most vigorous responses in sign-selective neurons (Fig. 5). 4. Behavioral and neuronal thresholds for the detection of small jamming signals were similar. Threshold for sign selectivity was reached when the amplitude ratio of the jamming signal to the EOD mimic, measured near the head surface, was 0.001. This value corresponds to a maximal temporal disparity (a necessary cue for performing a correct JAR) of 1 to 2 microseconds for signals received by the two sides of the body in a transverse jamming field (Fig. 7). 5. The effects of two jamming fields, offered orthogonally to each other, may interact nonlinearly at the behavioral as well as at the neuronal level. A positive Df presented in one field may suppress behavioral and neuronal responses to modulations of the sign of Df in the other field (Fig. 8c).     

Unravelling genetics at the top: mountain islands or isolated belts?

Background and Aims

In mountain plant populations, local adaptation has been described as one of the main responses to climate warming, allowing plants to persist under stressful conditions. This is especially the case for marginal populations at their lowest elevation, as they are highly vulnerable. Adequate levels of genetic diversity are required for selection to take place, while high levels of altitudinal gene flow are seen as a major limiting factor potentially precluding local adaptation processes. Thus, a compromise between genetic diversity and gene flow seems necessary to guarantee persistence under oncoming conditions. It is therefore critical to determine if gene flow occurs preferentially between mountains at similar altitudinal belts, promoting local adaptation at the lowest populations, or conversely along altitude within each mountain.

Methods

Microsatellite markers were used to unravel genetic diversity and population structure, inbreeding and gene flow of populations at two nearby altitudinal gradients of Silene ciliata, a Mediterranean high-mountain cushion plant.

Key Results

Genetic diversity and inbreeding coefficients were similar in all populations. Substantial gene flow was found both along altitudinal gradients and horizontally within each elevation belt, although greater values were obtained along altitudinal gradients. Gene flow may be responsible for the homogeneous levels of genetic diversity found among populations. Bayesian cluster analyses also suggested that shifts along altitudinal gradients are the most plausible scenario.

Conclusions

Past population shifts associated with glaciations and interglacial periods in temperate mountains may partially explain current distributions of genetic diversity and population structure. In spite of the predominance of gene flow along the altitudinal gradients, local genetic differentiation of one of the lower populations together with the detection of one outlier locus might support the existence of different selection forces at low altitudes.     

Octreotide in the treatment of malignant thymoma – Case report

Thymomas are the most common mediastinal tumors. Systemic therapy for patients with unresectable or recurrent thymomas is a challenging field in the current oncology research. There is some evidence that somatostatin analogs combined with corticosteroids may have a role in the treatment of advanced malignant thymoma; however, the role of these agents have not been fully evaluated.Case reportA 39-year-old man with metastatic thymoma was administered long-acting depot injection form of octreotide. Octreotide scan before the treatment initiation revealed low uptake. CT control after three months of the treatment revealed marked regression of pleural metastases, while the primary tumor mass remained stable. The treatment response was lasting for 9 months.ConclusionWe describe an interesting case of marked clinical and radiological response of advanced malignant thymoma to the treatment with octreotide in a heavily pre-treated patient, even though octreotide scan revealed low uptake.     

RACK1 research – ships passing in the night?

It should not be surprising that a protein with a name like RACK1 – short for receptor for activated C kinase 1 – is found in a variety of signaling complexes. Its alternative name, the splendidly unmemorable GNB2L1 – short for guanine nucleotide-binding protein subunit beta-2-like 1 – should reinforce this link to signaling complexes. There are currently over 400 publications listed in PubMed mentioning RACK1/GNB2L1 in the abstract, so it is certainly an actively studied protein with much involvement in different aspects of cell regulation being reported. RACK1 binds to the 40S ribosomal subunit, suggesting it links cell regulation and translation. It is also a target of intracellular parasites. And yet does this protein have the profile that it should? And why are there two kinds of RACK1 researcher who do not seem to communicate well?     

Humans at the top of the food web: are coastal benthic communities at Rapa Nui affected by fishing?

Environmental Biology of Fishes - Species overexploitation has simplified food webs worldwide, resulting in the degradation of ecosystems relative to their natural state. Fishes are the most...     

Internal auditory canal metastasis mimicking a vestibular schwannoma at presentation – a case report and review of the literature

Metastasis to the internal auditory canal from breast carcinoma is extremely rare and difficult to diagnose. It radiologically mimics vestibular schwannoma and can occur as a first manifestation of systemic relapse after a long disease-free interval in patients previously treated for early breast cancer. The diagnosis is usually made retrospectively and the optimal management of such metastasis following complete resection remains undefined.     

Economy and environment of Bronze Age settlements – Terramaras – on the Po Plain (Northern Italy): first results from the archaeobotanical research at the Terramara di Montale

The paper presents a synthesis of the on-site archaeobotanical investigations of the Terramara di Montale, one of the most important sites of the Terramara cultural system which characterised the Po Plain in the Middle-Late Bronze Age (1650–1200 b.c.). Samples for pollen analysis and macroremains, including seed/fruit and wood/charcoal records, were collected from stratigraphic sequences and occupation levels during the excavations 1996–2001. The results permitted the reconstruction of the main characteristics of the landscape which at the onset of the Terramara rapidly passed from a natural, more forested landscape with mixed oak wood and conifers to a more open and anthropic landscape characterised by cereal fields, pastures and meadows. People felled oaks and other trees such as Populus/Salix and Fraxinus to make piles or walls for houses. Wood from these species was also recorded as charcoal in the hearths. Palynological and carpological data show that the inhabitants of the Terramara largely founded their economy on cereals (mainly Triticum aestivum/durum, T. dicoccum and Hordeum vulgare). They also grew a few legumes (Vicia faba var. minor, Vicia sp. and Lens culinaris). There was also grazing by domestic animals, mainly ovicaprines but also pigs and cattle, and these were fed exploiting wild plants such as Carpinus. In the paper the four main steps of the history of the Terramara are described (before the Terramara, the onset, the Terramara phase, the decline) during which both human influence and climatic changes were important. At the onset of the Terramara (around 1600 b.c.) a warm and possibly dry phase occurred. The intense use of the territory and a climatic deterioration at around 1300 b.c. might have triggered the decline of the Terramara di Montale.     

Addressing ethical issues in H3Africa research – the views of research ethics committee members

In June 2014, the H3Africa Working Group on Ethics organised a workshop with members of over 40 research ethics committees from across Africa to discuss the ethical challenges raised in H3Africa research, and to receive input on the proposed H3Africa governance framework. Prominent amongst a myriad of ethical issues raised by meeting participants were concerns over consent for future use of samples and data, the role of community engagement in large international collaborative projects, and particular features of the governance of sample sharing. This report describes these concerns in detail and will be informative to researchers wishing to conduct genomic research on diseases pertinent to the African research context.