A molecular understanding of complementary chromatic adaptation

Photosynthetic activity and the composition of the photosynthetic apparatus are strongly regulated by environmental conditions. Some visually dramatic changes in pigmentation of cyanobacterial cells that occur during changing nutrient and light conditions reflect marked alterations in components of the major light-harvesting complex in these organisms, the phycobilisome. As noted well over 100 years ago, the pigment composition of some cyanobacteria is very sensitive to ambient wavelengths of light; this sensitivity reflects molecular changes in polypeptide constituents of the phycobilisome. The levels of different pigmented polypeptides or phycobiliproteins that become associated with the phycobilisome are adjusted to optimize absorption of excitation energy present in the environment. This process, called complementary chromatic adaptation, is controlled by a bilin-binding photoreceptor related to phytochrome of vascular plants; however, many other regulatory elements also play a role in chromatic adaptation. My perspectives and biases on the history and significance of this process are presented in this essay. This revised version was published online in August 2006 with corrections to the Cover Date.     

The enigma of guanacos in the Falkland Islands: the legacy of John Hamilton

Aim To address the biogeographical enigma of why guanacos (Lama guanicoe) are in the Falkland Islands we investigated the following questions: (1) What was the origin of the introduced guanacos? (2) What were the initial population sizes? (3) Why are they found only on one island? and (4) Who was John Hamilton and what role did he play? Location The Falkland Islands are located in the South Atlantic Ocean 600 km east of Patagonia at the southern end of South America. While dominated by East and West Falkland Islands, the archipelago is composed of some 750 islands. Sedge and Staats Islands, two small outlying islands of West Falkland, are the focus of this paper. Methods Historical information was collected from known relevant documents housed at the Falkland Islands Government Archives in Stanley, and personal interviews conducted with past and present residents of West Falklands. Research expeditions were made to Staats Island in 1999, 2002 and 2003 to assess the guanaco population size, distribution and social structure. Results Guanacos were unsuccessfully introduced in 1862 to East Falkland south of Mt Pleasant where Prince Alfred hunted them in 1871. John Hamilton, Scottish immigrant to the Falklands and Patagonia of southern Argentina and Chile, was the driving force in the introduction of guanacos from the region of Rio Gallegos, Argentina during the 1930s. The guanaco was one of several wildlife species he introduced, however, only the guanaco, Patagonia grey fox (Dusicyon griseus) and perhaps the sea otter (Lutra felina) survive. Hamilton's acting agent, Jimmy Miller, imported four shipments totalling 26 guanacos from 1934 to 1939. In 1934 the Falkland Government authorized Miller to introduce guanacos to Sedge Island, all 11 of which disappeared. Whether intentional or accidental, 15 guanacos were taken to Staats Island, an islet of 500 ha on the western edge of the archipelago. Historically, guanacos are unexpected on Staats Island because documentation authorizing their introduction is unknown. Guanaco numbers have fluctuated widely on Staats Island for 65 years primarily due to culling. In 1959 the population was dangerously close to extirpation, but today 400 thrive there. A severely reduced gene pool and genetic bottlenecking were suggested by recent field studies, revealing preliminary evidence of deleterious consequences of inbreeding. Main conclusions John Hamilton, spirited and visionary Scottish immigrant to the Falklands in the early 1880s, was responsible for the introduction of guanacos into the Falkland Islands. While there are some gaps in the historical events, the enigma of how and why guanacos were introduced to a single island in the South Atlantic Ocean is understood. Today, Staats Island, as a closed system, is a rare natural experiment in progress. It offers unique opportunities for addressing advanced questions in ungulate population, behavioural and genetic ecology. The population potentially also represents breeding stock for farming the guanaco's highly valuable wool on other islands. Thus, among his many efforts to practice land stewardship and promote economic diversity through the introduction of Patagonian wildlife, a remaining legacy of John Hamilton to the Falkland Islands is unmistakably the guanacos of Staats Island.     

Strategic analysis in evolutionary genetics and the theory of games

This paper is written in memory of John Maynard Smith. In a brief survey it discusses essential aspects of how game theory in biology relates to its counterpart in economics, the major transition in game theory initiated by Maynard Smith, the discrepancies between genetic and phenotypic models in evolutionary biology, and a balanced way of reconciling these models. In addition, the paper discusses modern problems in understanding games at the genetic level using the examples of conflict between endosymbionts and their hosts, and the molecular interactions between parasites and the mammalian immune system.     

Statistics for disinterested scientists.

This paper presents a brief introduction to some basic statistical tools and techniques with examples applied to biological data. Perhaps after becoming more familiar with statistics and more appreciative of their power in extracting information from data the previously fearful and skeptical researcher may be more inclined to make them an integral part of his research technique and also include them in his publications. For problems of greater difficulty, consultation at the early stages, preferably before undertaking the project, with a good biostatistician is suggested.     

The control of the anteroposterior and dorsoventral axes in embryonic chick limbs constructed of dissociated and reaggregated limb-bud mesoderm

In the 3- to 4-day embryonic avian limb bud, a unique zone of mesodermal tissue is located posteriorly at the junction of bud and body wall. Appropriately grafted to a host limb bud, it induces the formation of a supernumerary limb outgrowth from preaxial tissue and determines that its posterior side will face the graft. It is called the zone of polarizing activity (ZPA).When limb-bud mesoderm is isolated, dissociated, reaggregated centrifugally, jacketed in the mesoderm-free hull of another limb bud, and grown as a graft on a host embryo, the recombinant frequently forms a limb-like structure terminating in digits that fail to show differentiation with respect to the anteroposterior axis. When, however, a bit of ZPA tissue is implanted in the recombinant subjacent to the anterior or posterior margin of the ectoderm, the resulting outgrowth shows a characteristic anteroposterior order of digits that corresponds to the placement of the implant, regardless of its relationship with the anteroposterior axis of the ectoderm or of the host embryo.Dorsoventral differentials have been recognized only in limbs formed from reaggregated leg-bud mesoderm. The direction of the dorsoventral axis always corresponds to the original axis of the ectodermal jacket regardless of the orientation of the recombinant on the host.     

Actions of morphine on prostate gland fructose metabolism

Varying doses of morphine sulfate (10, 20 or 40 mg/kg daily × 10) were observed to suppress metabolic activities in the mouse prostate gland. Prostate gland fructose, an index of androgenic activity, was significantly reduced by these dose regimes of morphine (P < 0.01). Injections of morphine sulfate (20 mg/kg daily × 10) led to an inhibitition in the $\text{in vitro}$ synthesis of both fructose^?14C and sorbitol^?14C from glucose^?14C by the prostate gland, part of which may have been due to decreased uptake of glucose by the gland. The $\text{in vitro}$ assimilation of 2-deoxyglucose^?14C by the prostate was also reduced by morphine treatment. The $\text{in vitro}$ actions of morphine (2 × 10^?3M) on the metabolism of radioactive glucose by the mouse prostate gland likewise revealed a significant reduction in the formation of sorbitol^?14C, but no decrease in fructose^?14C formation. These results indicate that both the $\text{in vitro}$ and $\text{in vivo}$ actions of morphine can inhibit fructose metabolism in the prostate gland.     

Willughby’s angel: the pintailed sandgrouse (Pterocles alchata)

Among paintings of birds thought to have been bought in 1663 in Nuremberg by Francis Willughby, and now housed in Nottingham University library, is the painting of a bird called Jangle de Languedoc. Unlike some of the other drawings, this particular one was never used by Ray in his Ornithology of Francis Willughby (1678), who had difficulty in identifying the bird. We show here that this painting was not bought in Nuremberg, but that it was obtained by Ray from Sir Thomas Crew, during his stay in Montpellier in 1665. Furthermore, had Ray looked at Gessner (Historiae animalium liber III qui est de avium natura. Christophus Froschoverus, Tiguri, 1555), Aldrovandi (Ornithologiae, tomus alter. Bononiae, apud Franciscum de Franciscis Senensem, 1600), Jonston (Historiae naturalis de avibus libri VI. Matthaeus Merianus, Frankfurt, 1650) and mostly at Charleton (Gualteri Charletoni Exercitationes de Differentiis & Nominibus Animalium. Theatro Sheldoniano, Oxford, 1677), he would have been able to identify the bird of the painting as alchata or “angel”, specifically a pintailed sandgrouse, Pterocles alchata.