Showing papers in "Naturwissenschaften in 2003"
TL;DR: QMP is responsible for the ovary-regulating pheromonal capability of queens from European-derived Apis mellifera subspecies and was as effective as queen extracts at ovary regulation.
Abstract: We report results that address a long-standing controversy in honey bee biology, the identity of the queen-produced compounds that inhibit worker honey bee ovary development. As the honey bee is the only organism for which identities have been proposed for any pheromone that regulates reproduction, the resolution of its identity is of broad significance. We examined the effects of synthetic honey bee queen mandibular pheromone (QMP), four newly identified queen retinue pheromone components, and whole-queen extracts on the ovary development of caged worker bees. The newly identified compounds did not inhibit worker ovary development alone, nor did they improve the efficacy of QMP when applied in combination. QMP was as effective as queen extracts at ovary regulation. Caged workers in the QMP and queen extract treatments had better developed ovaries than did workers remaining in queenright colonies. We conclude that QMP is responsible for the ovary-regulating pheromonal capability of queens from European-derived Apis mellifera subspecies.
312 citations
TL;DR: Why the theory of autopoiesis had a difficult time being accepted into the mainstream of life-science research is commented on and how cognition, so defined, permits us to build a bridge between biology and cognitive science is shown.
Abstract: The aim of the paper is to review critically the notion of autopoiesis as presented by Maturana and Varela. In particular, recognizing that there are difficulties in obtaining a complete and clear picture from the primary literature, an effort is made to present a coherent view—also based on many years of personal contact with Francisco Varela. The paper begins with a few historical notes to highlight the cultural background from which the notion of autopoiesis arose. The basic principles of autopoiesis as a theory of cellular life are then described, emphasizing also what autopoiesis is not: not an abstract theory, not a concept of artificial life, not a theory about the origin of life—but rather a pragmatic blueprint of life based on cellular life. It shown how this view leads to a conceptually clear definition of minimal life and to a logical link with related notions, such as self-organization, emergence, biological autonomy, auto-referentiality, and interactions with the environment. The perturbations brought about by the environment are seen as changes selected and triggered by the inner organization of the living. These selective coupling interactions impart meaning to the minimal life and are thus defined by Maturana and Varela with the arguable term of "cognition". This particular view on the mutual interactions between living organism and environment leads these authors to the notion of "enaction", and to the surprising view that autopoiesis and cognition are two complementary, and in a way equivalent, aspects of life. It is then shown how cognition, so defined, permits us to build a bridge between biology and cognitive science. Autopoiesis also allows one to conceive chemical models of minimal cellular life that can be implemented experimentally. The corresponding work on "chemical autopoiesis" is then reviewed. The surprising impact of autopoiesis in the social sciences ("social autopoiesis") is also briefly discussed. This review also comments on why the theory of autopoiesis had, and still has, a difficult time being accepted into the mainstream of life-science research. Finally, it is pointed out that the new interest in system biology and complexity theories may lead to a reappraisal of autopoiesis and related notions, as outlined also by other authors, such as Tibor Ganti and Stuart Kauffmann.
254 citations
TL;DR: Results from recent studies on Macrotermes bellicosus are reviewed that considered the interdependence of ambient temperature, thermoregulation, ventilation and mound architecture, and that question some of the fundamental paradigms of termite mounds.
Abstract: Some of the most sophisticated of all animal-built structures are the mounds of African termites of the subfamily Macrotermitinae, the fungus-growing termites. They have long been studied as fascinating textbook examples of thermoregulation or ventilation of animal buildings. However, little research has been designed to provide critical tests of these paradigms, derived from a very small number of original papers. Here I review results from recent studies on Macrotermes bellicosus that considered the interdependence of ambient temperature, thermoregulation, ventilation and mound architecture, and that question some of the fundamental paradigms of termite mounds. M. bellicosus achieves thermal homeostasis within the mound, but ambient temperature has an influence too. In colonies in comparably cool habitats, mound architecture is adapted to reduce the loss of metabolically produced heat to the environment. While this has no negative consequences in small colonies, it produces a trade-off with gas exchange in large colonies, resulting in suboptimally low nest temperatures and increased CO(2) concentrations. Along with the alteration in mound architecture, the gas exchange/ventilation mechanism also changes. While mounds in the thermally appropriate savannah have a very efficient circular ventilation during the day, the ventilation in the cooler forest is a less efficient upward movement of air, with gas exchange restricted by reduced surface exchange area. These results, together with other recent findings, question entrenched ideas such as the thermosiphon-ventilation mechanism or the assumption that mounds function to dissipate internally produced heat. Models trying to explain the proximate mechanisms of mound building, or building elements, are discussed.
192 citations
TL;DR: This study summarises the present knowledge on unrestrained decomposition of a corpse, combining results gained both in forensic medicine and in geosciences.
Abstract: The unrestrained decomposition of a corpse involves the consecutive processes of autolysis, putrefaction and decay. Ideally, decomposition is completed within the regular resting time (15-25 years) and leads to the entire skeletalisation of the corpse. Adipocere, a greyish fatty substance formed during decomposition, is regarded as a spontaneous inhibition of post-mortem changes; it makes the corpse almost entirely resistant to decomposition and makes it impossible to use the same graves again. This creates problems for local governments with regard to the generally growing demand for burial ground. Apart from corpse-specific characteristics (e.g. sex, age, physique, cause of death), method of burial (e.g. material of the coffin, depth of grave, individual or mass grave, clothing) and time of burial, the conditions of the resting place (geology, topography, soil properties and frequency of use, air, water, and heat budget), in particular, have a special impact on adipocere formation. This study summarises the present knowledge on this phenomenon, combining results gained both in forensic medicine and in geosciences.
167 citations
TL;DR: The development of substitute materials for arsenic applications in the agricultural and forestry industries and controls of arsenic emissions from the coal industry may be possible strategies to significantly decrease arsenic pollution sources and dissipation rates into the environment.
Abstract: Arsenic, a carcinogenic trace element, threat- ens not only the health of millions of humans and other living organisms, but also global sustainability. We present here, for the first time, the global industrial-age cumulative anthropogenic arsenic production and its potential accumulation and risks in the environment. In 2000, the world cumulative industrial-age anthropogenic arsenic production was 4.53 million tonnes. The world- wide coal and petroleum industries accounted for 46% of global annual gross arsenic production, and their overall contribution to industrial-age gross arsenic production was 27% in 2000. Global industrial-age anthropogenic As sources (as As cumulative production) follow the order: As mining production >As generated from coal >As generated from petroleum. The potential industrial-age anthropogenic arsenic input in world arable surface in 2000 was 2.18 mg arsenic kg �1 , which is 1.2 times that in the lithosphere. The development of substitute materials for arsenic applications in the agricultural and forestry industries and controls of arsenic emissions from the coal industry may be possible strategies to significantly decrease arsenic pollution sources and dissipation rates into the environment.
160 citations
TL;DR: A high positive correlation between the molecular activity (ATP min−1) of individual Na+K+ATPase units and the content of DHA in the surrounding membrane bilayer is reported, which represents a fundamental relationship underlying metabolic activity, but may also represent a link between reduced levels of D HA and neurological dysfunction.
Abstract: The omega-3 polyunsaturate, docosahexaenoic acid (DHA), plays a number of biologically important roles, particularly in the nervous system, where it is found in very high concentrations in cell membranes. In infants DHA is required for the growth and functional development of the brain, with a deficiency resulting in a variety of learning and cognitive disorders. During adulthood DHA maintains normal brain function and recent evidence suggests that reduced DHA intake in adults is linked with a number of neurological disorders including schizophrenia and depression. Here we report a high positive correlation between the molecular activity (ATP min(-1)) of individual Na(+)K(+)ATPase units and the content of DHA in the surrounding membrane bilayer. This represents a fundamental relationship underlying metabolic activity, but may also represent a link between reduced levels of DHA and neurological dysfunction, as up to 60% of energy consumption in the brain is linked to the Na(+)K(+)ATPase enzyme.
151 citations
TL;DR: To determine the extent of genetic differences in boldness and shoaling within and between zebrafish (Danio rerio) populations, and to examine the genetic basis of shoaling behaviour in general, a study involved laboratory-raised fish derived from four wild-caught populations.
Abstract: Population differences in anti-predator behaviour have been demonstrated in several species, although less is known about the genetic basis of these traits. To determine the extent of genetic differences in boldness (defined as exploration of a novel object) and shoaling within and between zebrafish (Danio rerio) populations, and to examine the genetic basis of shoaling behaviour in general, we carried out a study that involved laboratory-raised fish derived from four wild-caught populations. Controlling for differences in rearing environment, significant inter-population differences were found in boldness but not shoaling. A larger shoaling experiment was also performed using one of the populations as the basis of a North Carolina type II breeding design (174 fish in total) to estimate heritability of shoaling tendency. A narrow-sense heritability estimate of 0.40 was obtained, with no apparent dominance effects.
147 citations
TL;DR: The most important aspects of biodiversity for conservation are reviewed, particularly primitive cultivars and wild relatives from the centers of origin, diversity, and cultivation.
Abstract: The science of agrobiodiversity has emerged during the last 10 years. We review here the most important aspects of biodiversity for conservation. One of the aims of agrobiodiversity research is to introduce or to re-introduce into present-day agriculture and horticulture more diversity from gene banks, botanical or zoological gardens, and other secondary sources of diversity. To enlarge the basis of agricultural and horticultural resources for human and animal nutrition, a sustainable use of these native and cultivated resources is necessary, including animal and plant genetic resources. The total number of botanical plant species cultivated as agricultural or horticultural crops is estimated at almost 7,000. However, only 30 major crop species "feed the world". Comparable numbers of animal species have been lost. The reduction in crop species and variety diversity, in particular, has led to the establishment of germplasm collections, so called gene banks, or ex situ collections. Six million plant accessions are conserved in gene banks worldwide. All these accessions belong to a very limited number of species. About half of them are advanced cultivars or breeders' lines, and only a third are landraces or old cultivars. Approximately 15% are wild relatives of crop species and weeds. Among other obvious gaps, minor crops and underutilized species are underrepresented in these collections, particularly primitive cultivars and wild relatives from the centers of origin, diversity, and cultivation. To date, only a third of all gene bank accessions have been fully characterized.
121 citations
TL;DR: In this article, it is shown that a partial thermodynamic order can eventually be attained for defined positions and compounds under steady-state conditions of metabolism, and the resulting general theory of the origin of non-statistical isotope distributions in biological systems permits the interpretation and prediction of isotope patterns and provides the scientific basis for the elucidation of biosyntheses and origin assignments of natural compounds.
Abstract: The intermolecular and intramolecular non-statistical distribution of the isotopes of the bio-elements in natural compounds must obviously be controlled by logical principles. However, a critical review of the available isotope patterns of natural compounds indicates that a previously discussed general thermodynamic order and its mechanistic foundation cannot satisfactorily explain all experimental data. In the present contribution it is shown that a partial thermodynamic order can eventually be attained for defined positions and compounds under steady-state conditions of metabolism. However, as biological systems are generally open and irreversible, many other in vivo isotope discriminations are dominated by kinetic isotope effects, even in context with reversible reactions. On the other hand, kinetic isotope effects can only become effective in vivo in combination with metabolic branching and the implied isotope shifts of the products are balanced by their relative yields. In vivo, the influences of thermodynamic and kinetic isotope effects are modulated by interferences of the actual metabolic conditions, such as the nature and kind of precursors, alternative metabolic pathways, metabolite pools and fluxes, and by reaction mechanisms. This is demonstrated by giving examples for the isotopes of hydrogen, carbon, nitrogen, oxygen and sulfur, while simultaneously the particularities of the individual elements are elaborated. The resulting general theory of the origin of non-statistical isotope distributions in biological systems permits the interpretation and prediction of isotope patterns and provides the scientific basis for the elucidation of biosyntheses and origin assignments of natural compounds.
117 citations
TL;DR: The size and coloration of some body characters seem to influence mate choice in many species, but the results suggest that the expression of the two traits may be regulated by different mechanisms.
Abstract: The size and coloration of some body charac- ters seem to influence mate choice in many species. Most animal colours are either structural or based on melanin or carotenoid pigments. It has recently been suggested that carotenoid-based or structural coloration may be a condition-dependent trait, whereas melanin-based color- ation is not; a difference that may be highly relevant when studying the evolution of multiple mating preferences. We tested this hypothesis in the great tit (Parus major). The size of the melanin breast band was not correlated to nutritional condition as estimated by the rate of tail growth (ptilochronology), controlling for locality, age, sex, year and season effects. However, the correlation was significant for the hue of yellow breast (carotenoid-based coloration), and the slopes of the regressions of the two pigments to growth bars differed significantly. These results suggest that the expression of the two traits may be regulated by different mechanisms.
111 citations
TL;DR: The recently reported Jeholornis represents the only known bird with a complete long skeletal tail except for Archaeopteryx, and it is concluded that the common ancestor of birds must have a more primitive tail than that in Archaeoporationx, confirming the side branch position of Archaeoperyx in the early avian evolution.
Abstract: The recently reported Jeholornis represents the only known bird with a complete long skeletal tail except for Archaeopteryx. Two newly discovered specimens referable to Jeholornis provide some important new information about its anatomy. The tail of Jeholornis is much longer than that of Archaeopteryx and comprises a maximum of 27 caudal vertebrae compared with only 23 in Archaeopteryx. More interestingly, the tail feathers are shaped more like those of dromaeosaurs than those of Archaeopteryx. We conclude that the common ancestor of birds must have a more primitive tail than that in Archaeopteryx, confirming the side branch position of Archaeopteryx in the early avian evolution. The synsacrum is composed of six sacrals, representing a transitional stage between Archaeopteryx and more advanced birds. The scapula of Jeholornis has a dorso-laterally exposed glenoid facet, and the coracoid has a supracoracoid foramen. The presence of a pair of fenestrae in the sternum of Jeholornis has further implications for the air-sac system in early birds.
TL;DR: It is argued that the yellow carotenoid coloration of goldfinches may be important in mutual mate choice and, thus, that sexual selection in this species may act upon female ornamentation, as well as the more obvious plumage signals of males.
Abstract: We investigated the mating patterns in 22 breeding pairs of wild American goldfinches (Carduelis tristis) with respect to their body size, condition, and carotenoid-based, yellow plumage colour. Using reflectance spectrometry, we objectively quantified plumage colours across the bird-visible wavelengths, revealing a unexpected UV peak in the reflectance spectrum from yellow feathers. We summarized our colour measurements using a principal components analysis to create a single variable, carotenoid PC1, that represents the intensity of this carotenoid-based yellow colour, a measure of phenotypic quality in this species. We found no evidence of assortative mating with respect to measures of body size or condition but there was positive assortative mating by carotenoid PC1, such that the yellow plumage colours of males and females were significantly correlated within pairs. We argue that the yellow carotenoid coloration of goldfinches may be important in mutual mate choice and, thus, that sexual selection in this species may act upon female ornamentation, as well as the more obvious plumage signals of males. Because assortative mating results in an increase in genetic variance, we suggest that this might be a mechanism that maintains variance in ornamental traits in spite of the variance-eroding effects of sexual selection.
TL;DR: It is shown that the lower temporal arcade was lost only once in diapsid evolution, and that the presence of the arch in "higher" diapsids is secondary, which is indicated by the different ratio between jugal and quadratojugal as well as by ontogeny.
Abstract: The temporal arches of diapsid reptiles have received attention for several decades. In particular, it has been observed that the lower temporal bar at the ventral margin of the cheek is frequently reduced due to the absence of a contact between jugal and quadratojugal. The loss of the arcade was formerly considered to be of high systematic value, but is now often interpreted as being autapomorphic for the respective taxon, and the presence of both arcades is generally regarded as a plesiomorphic feature. Here I show, based on a cladistic analysis as well as on further anatomical evidence, that the lower temporal arcade was lost only once in diapsid evolution, and that the presence of the arch in "higher" diapsids is secondary, which is indicated by the different ratio between jugal and quadratojugal as well as by ontogeny. This result also sheds new light on the understanding of the cheek configuration of enigmatic taxa such as ichthyosaurs and turtles.
TL;DR: Investigation of differences in task specialisation between large and small colonies of the ponerine ant Rhytidoponera metallica found that workers in small colonies have a lower contact rate between nestmates and a greater variability in time between contacts than workers from large colonies.
Abstract: In theory, larger colonies of social insects should have greater colony organisation. While inter-specific comparative studies provide support for this idea, there is little direct intra-specific evidence. We investigated differences in task specialisation between large (>450 workers) and small (<80 workers) colonies of the ponerine ant Rhytidoponera metallica. Observations of individually marked young or old workers revealed greater task specialisation in large colonies. Age polyethism was detected in large but not small colonies. In large colonies, old workers spent significantly more time foraging than young workers did, while young workers spent more time caring for brood. In small colonies, young and old workers spent a similar amount of time foraging and caring for brood. This difference in task allocation patterns in large and small colonies was associated with a difference in contact rates between workers. Workers in small colonies have a lower contact rate between nestmates and a greater variability in time between contacts than workers from large colonies.
TL;DR: It is concluded that experimental and epidemiological research can provide further insights into common denominators of these chronic processes and may offer novel and uniform targets for prevention.
Abstract: This paper reviews abundant evidence suggesting that causes and course of aging and cancers can be considered as being both light- and rhythm-related. We define chronodisruption as a relevant disturbance of orderly biological rhythms over days and seasons and years in man. Light is the primary external mediator and melatonin a primary internal intermediary of such disturbances, which can result in earlier deaths via premature aging and cancers. We conclude that experimental and epidemiological research can provide further insights into common denominators of these chronic processes and may offer novel and uniform targets for prevention.
TL;DR: It is provided the first evidence from primates that age-specific reproductive output among males is not a consequence of age-related changes in body condition, but reflects social and demographic factors.
Abstract: In many mammalian species, male reproductive success appears to climb sharply at young adulthood, form a brief plateau during prime ages, and decline among older animals, a pattern often attributed to reduced physical condition with ageing. However, solid evidence to either substantiate or refute this profile among nonhuman primates is lacking. Here, we combine a decade of genetic analysis of paternity among free-ranging rhesus macaques, Macaca mulatta, with information about body condition in order to evaluate how changes in morphology might govern age-specific reproduction among males. We show that age-specific reproductive success traverses the same life history profile as found in other mammals, but reductions in reproductive output with advanced age were associated with reduced chances of survivorship rather than accompanied by diminished body condition. We demonstrate that variance in male age at onset of reproduction is three times greater than variance in female age at onset of reproduction. We provide the first evidence from primates that age-specific reproductive output among males is not a consequence of age-related changes in body condition, but reflects social and demographic factors.
TL;DR: This work used American foulbrood (caused by the bacterium Paenibacillus larvae) as a model pathogen and found that patrilines within colonies do indeed vary in their resistance to this disease.
Abstract: Explanations for the evolution of multiple mating by social insect (particularly honey bee) queens have been frequently sought. An important hypothesis is that multiple mating is adaptive because it increases intracolonial genetic diversity and thereby reduces the likelihood that parasites or pathogens will catastrophically infect a colony. We tested one assumption of this model: that honey bee worker patrilines should differ in disease resistance. We used American foulbrood (caused by the bacterium Paenibacillus larvae) as a model pathogen. We found that patrilines within colonies do indeed vary in their resistance to this disease.
TL;DR: Among more than 10,000 specimens x-rayed, tumors were only found in Cretaceous hadrosaurs (duck-billed dinosaurs), including hemangiomas and metastatic cancer (previously identified in dinosaurs), desmoplastic fibroma, and osteoblastoma.
Abstract: Occasional reports in isolated fragments of dinosaur bones have suggested that tumors might represent a population phenomenon. Previous study of humans has demonstrated that vertebral radiology is a powerful diagnostic tool for population screening. The epidemiology of tumors in dinosaurs was here investigated by fluoroscopically screening dinosaur vertebrae for evidence of tumors. Computerized tomography (CT) and cross-sections were obtained where appropriate. Among more than 10,000 specimens x-rayed, tumors were only found in Cretaceous hadrosaurs (duck-billed dinosaurs). These included hemangiomas and metastatic cancer (previously identified in dinosaurs), desmoplastic fibroma, and osteoblastoma. The epidemiology of tumors in dinosaurs seems to reflect a familial pattern. A genetic propensity or environmental mutagens are suspected.
TL;DR: Gas chromatography–mass spectrometry analysis of A. glabripennis adults' whole body cuticular extracts indicates that a series of long-chain hydrocarbons comprise the cuticular waxes of both sexes.
Abstract: Field observations of the Asian longhorned beetle (Anoplophora glabripennis) mating behavior in China suggested that a female-produced contact pheromone was almost certainly involved in sex recognition. Gas chromatography–mass spectrometry (GC-MS) analysis of A. glabripennis adults' whole body cuticular extracts indicates that a series of long-chain hydrocarbons comprise the cuticular waxes of both sexes. Although for the most part the GC profiles are similar for the two sexes, five monounsaturated compounds were consistently more abundant in samples from females than in those from males. These compounds were identified as (Z)-9-tricosene, (Z)-9-pentacosene, (Z)-7-pentacosene, (Z)-9-heptacosene, and (Z)-7-heptacosene in the approximate ratio of 1:2:2:8:1, respectively. Antennal and palpi contact to a polypropylene micro-centrifuge tube coated with a synthetic mixture of the five compounds stimulated copulatory behavior in males.
TL;DR: Sexual selection theory is used to develop a logistically simple, yet effective, method for the manipulation of female reproductive behavior for conservation goals, and females showed an unusually strong preference for the familiar-odor male, as indicated by several behavioral measures of mate preference.
Abstract: Here we use sexual selection theory to develop a logistically simple, yet effective, method for the manipulation of female reproductive behavior for conservation goals. Mate choice leading to nonrandom mating patterns can exacerbate the loss of genetic diversity in small populations. On theoretical grounds, females should choose high-quality mates. A prediction stemming from chemical communication theory is that competitive males will be better able to saturate an area with scent marks. If this is true, females should mate preferentially with males whose odors they encounter most frequently. We tested this hypothesis with the pygmy loris, Nycticebus pygmaeus, a threatened and poorly studied nocturnal prosimian. For several weeks females were exposed repeatedly to the urine from a particular male, and were then allowed to choose between a male whose odors were familiar and one whose odors were novel. Females showed an unusually strong preference for the familiar-odor male, as indicated by several behavioral measures of mate preference. Conservation managers can use this method as a tool to obtain reproductive pairings that will maximize genetic compatibility and diversity. For example, unsuccessful males may be given the opportunity to reproduce. In captive populations, studbook managers often select pairs in order to optimize outbreeding, but these selected pairings may not coincide with the preferences of the individual animals involved. Although several authors have made theoretical arguments for manipulating mate choice for conservation, this is a novel test of a proximate mechanism that can be manipulated, cultivating applications rather than mere implications.
TL;DR: It is concluded that members of the Hox family are likely to fulfill essential roles of great functional diversity in hair that require complex transcriptional control mechanisms to ensure proper spatio-temporal patterns of Hox gene expression at homeostatic levels.
Abstract: The evolutionarily conserved Hox gene family of transcriptional regulators has originally been known for specifying positional identities along the longitudinal body axis of bilateral metazoans, including mouse and man It is believed that subsequent to this archaic role, subsets of Hox genes have been co-opted for patterning functions in phylogenetically more recent structures, such as limbs and epithelial appendages Among these, the hair follicle is of particular interest, as it is the only organ undergoing cyclical phases of regression and regeneration during the entire life span of an organism Furthermore, the hair follicle is increasingly capturing the attention of developmental geneticists, as this abundantly available miniature organ mimics key aspects of embryonic patterning and, in addition, presents a model for studying organ renewal The first Hox gene shown to play a universal role in hair follicle development is Hoxc13, as both Hoxc13-deficient and overexpressing mice exhibit severe hair growth and patterning defects Differential gene expression analyses in the skin of these mutants, as well as in vitro DNA binding studies performed with potential targets for HOXC13 transcriptional regulation in human hair, identified genes encoding hair-specific keratins and keratin-associated proteins (KAPs) as major groups of presumptive Hoxc13 downstream effectors in the control of hair growth The Hoxc13 mutant might thus serve as a paradigm for studying hair-specific roles of Hoxc13 and other members of this gene family, whose distinct spatio-temporally restricted expression patterns during hair development and cycling suggest discrete functions in follicular patterning and hair cycle control The main conclusion from a discussion of these potential roles vis-a-vis current expression data in mouse and man, and from the perspective of the results obtained with the Hoxc13 transgenic models, is that members of the Hox family are likely to fulfill essential roles of great functional diversity in hair that require complex transcriptional control mechanisms to ensure proper spatio-temporal patterns of Hox gene expression at homeostatic levels
TL;DR: The results show conclusively that hydrocarbons are produced by oenocytes not only in insects whose oenocyte are localized within the hemocoel, but also in those insects whoseOenocytes are within the abdominal integument, and support a hemolymph pathway for transport and delivery of hydrocarbon to both external and internal tissues.
Abstract: In insects, hydrocarbons waterproof the cuticle, protect the insect from the external environment, and serve as semiochemicals or their metabolic precursors. In the German cockroach, Blattella germanica, hydrocarbons are synthesized by the abdominal integument, but the precise site of biosynthesis is not known. We developed a method for separation of oenocytes from other cells in the abdominal integument using enzymatic dissociation followed by Percoll gradient centrifugation. Radiolabeled propionate was then used to monitor de novo synthesis of hydrocarbons by dissociated cells. Oenocyte-enriched cell suspensions of abdominal sternites synthesized hydrocarbons, whereas suspensions enriched with epidermal cells did not. Our results show conclusively that hydrocarbons are produced by oenocytes not only in insects whose oenocytes are localized within the hemocoel, but also in those insects whose oenocytes are within the abdominal integument. Furthermore, these data support a hemolymph pathway for transport and delivery of hydrocarbons to both external and internal tissues, including the epicuticle, fat body, and ovaries.
TL;DR: Female yellow fever mosquitoes were presented with two millipede secretory compounds and exhibited fewer landings, fed less frequently, and flew more frequently (a possible indication of repellency) in the presence of membranes treated with benzoquinones than with controls.
Abstract: Neotropical monkeys of the genus Cebus anoint themselves by rubbing arthropods and plants against their pelage. A recent study has shown that free-ranging wedge-capped capuchin monkeys (C. olivaceus) in Venezuela self-anoint with a benzoquinone-secreting millipede, an activity by which they are hypothesized to appropriate chemical deterrents of mosquitoes. To evaluate the plausibility of this hypothesis, female yellow fever mosquitoes (Aedes aegypti) were presented with two millipede secretory compounds, 2-methyl-1,4-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone, on nylon-reinforced silicone membranes placed over wells filled with human blood, a highly preferred food. Mosquitoes exhibited fewer landings, fed less frequently, and flew more frequently (a possible indication of repellency) in the presence of membranes treated with benzoquinones than with controls. These compounds also elicit self-anointing in captive male and female tufted (C. apella) and white-faced (C. capucinus) capuchin monkeys.
TL;DR: Burrow pattern was influenced by the time of the year, becoming more reticulated at the peak of the dry season when soil was dry and hard and the soil was deposited in tunnels rather than transported to mounds.
Abstract: Little is known about seasonal changes in burrowing activity and burrow architecture in subterranean African mole-rats (Bathyergidae, Rodentia). The solitary genus Heliophobius is the least known genus of this family. We examined burrow systems of the silvery mole-rat (Heliophobius argenteocinereus) in Malawi in two periods of the dry season. Burrow pattern was influenced by the time of the year, becoming more reticulated at the peak of the dry season when soil was dry and hard. Overall digging activity did not cease during the dry season; yet burrowing strategy changed and the soil was deposited in tunnels rather than transported to mounds. The length of burrow systems was correlated with the body mass of the respective occupants. In spite of their solitary habits--and contrary to the prediction of the aridity food-distribution hypothesis--silvery mole-rats are able to occupy poor habitats with low food supply.
TL;DR: Both Pteropus pumilus and Ptenochirus jagori can not only locate fruits by their odour but can also discriminate between ripe and unripe fruits of the same species by olfaction.
Abstract: Double-choice experiments with three adult males of the little golden-mantled flying fox, Pteropus pumilus, and ten adult greater musky fruit bats, Ptenochirus jagori (both Megachiroptera: Pteropodidae), demonstrate that they are able to discriminate accurately between an empty dish and a dish containing fruits of one of several species by odour alone. Tests were run using fruits of six fruit species for Pteropus pumilus and five fruit species for Ptenochirus jagori. The fruit species used are known to be consumed in the wild by Ptenochirus jagori and are, with two exceptions, species of the natural rain-forest habitat. This is the first study to show that fruit bats are also able to assess the ripeness of a fruit exclusively by its odour. The bats preferred ripe over unripe fruits of the same species. Thus, both Pteropus pumilus and Ptenochirus jagori can not only locate fruits by their odour but can also discriminate between ripe and unripe fruits of the same species by olfaction. The results confirm and expand earlier findings on the role of olfactory cues in the orientation of foraging pteropodids.
TL;DR: It is speculated that as functional genomics teaches us more about the nature of disease, molecular farming will produce many of the protein therapeutics that can remedy it.
Abstract: 'Molecular farming' is the production of valuable recombinant proteins in transgenic organisms on an agricultural scale. While plants have long been used as a source of medicinal compounds, molecular farming represents a novel source of molecular medicines, such as plasma proteins, enzymes, growth factors, vaccines and recombinant antibodies, whose medical benefits are understood at a molecular level. Until recently, the broad use of molecular medicines was limited because of the difficulty in producing these proteins outside animals or animal cell culture. The application of molecular biology and plant biotechnology in the 1990s showed that many molecular medicines or vaccines could be synthesised in plants and this technology is termed 'molecular farming'. It results in pharmaceuticals that are safer, easier to produce and less expensive than those produced in animals or microbial culture. An advantage of molecular farming lies in the ability to perform protein production on a massive scale using hectares of cultivated plants. These plants can then be harvested and transported using the agricultural infrastructure. Thus, molecular farming allows rapid progress from genetic engineering to crop production, and new cash crops producing recombinant proteins are already being commercially exploited. We speculate that as functional genomics teaches us more about the nature of disease, molecular farming will produce many of the protein therapeutics that can remedy it.
TL;DR: It is concluded that females mated to aggressive-playback, high-ranking males pursued mixed mating strategies similar to those of females mating to low-ranking Males, support the idea that male performance in song contests may influence multiple aspects of female reproductive choices.
Abstract: In animals where males engage in signalling interactions, females might evaluate male–male contests to inform their reproductive choices. We used interactive playback to engage territorial male black-capped chickadees (Poecile atricapillus) of known dominance status in countersinging contests with an aggressive or submissive opponent. Previous analysis of these data showed that high-ranking males who received aggressive playback were more likely to be cuckolded. Here we describe the particular reproductive decisions of females whose partners received aggressive versus submissive playback. The proportion of extra-pair young per brood was higher for females paired to high-ranking males that received aggressive playback compared to submissive playback, and similar to levels in broods of females paired to low-ranking males. We found no strong predictors of whether high-ranking subjects lost paternity following aggressive playback. Females usually preferred extra-pair sires with high dominance status. When females had extra-pair fertilizations with low-ranking males, females chose males who had received submissive playback. We conclude that females mated to aggressive-playback, high-ranking males pursued mixed mating strategies similar to those of females mated to low-ranking males. Our results support the idea that male performance in song contests may influence multiple aspects of female reproductive choices.
TL;DR: The current view of how RNAi works in different eukaryotic species and its high potential for functional genomics and in rational drug design is presented.
Abstract: Now that the sequencing of many genomes has been completed, the basic challenges are finding the genes and predicting their functions. Up until now, a large information gap has existed between the knowledge of genome sequence and our knowledge of protein function. The assessment of gene function may be performed using the tools of reverse genetics, including knock-out mice, antisense oligomers, aptamers, and ribozymes. These approaches have been superseded by RNA interference (RNAi), which exhibits much more potency for the investigation of protein function than the techniques listed above. As already known some years ago, RNAi is based on an ancient anti-viral defense mechanism in lower eukaryotes. It is induced by double-stranded RNA and its processing to 21–23 nt small interfering RNAs (siRNAs), which cause the degradation of homologous endogenous mRNA. The way RNAi works has still to be determined, but it already serves as a first-choice approach to generate loss-of-function phenotypes among a broad variety of eukaryotic species, such as nematodes, flies, plants, fungi and mammals. RNAi also represents an extremely powerful tool, becoming a therapeutic approach to curing infectious diseases originated by viral or parasitic invasion. In this review we present the current view of how RNAi works in different eukaryotic species and its high potential for functional genomics and in rational drug design.
TL;DR: The concept of sustainable chemistry is reviewed, which is still in its early development, and the societal aspect of SC is illustrated with the examples of environmental chemistry, green chemistry and the environmental assessment of chemical products.
Abstract: We review here the concept of sustainable chemistry (SC), which is still in its early development. One important element of SC is commonly defined as chemical research aiming at the optimization of chemical processes and products with respect to energy and material consumption, inherent safety, toxicity, environmental degradability, and so on. An increasing number of assessment systems containing quantitative indicators for these aspects are currently being developed. In addition, however, SC should also address the societal aspect of sustainability. With respect to scientific research, the societal aspect is defined here by two requirements: (1) the assumptions, objectives and implications of chemical research and its technical application should be made more transparent to various societal actors; (2) uncertainty and ignorance should be treated more explicitly in the course of scientific research. Meeting these requirements is necessary in order to lift the division between the allegedly disinterested and non-normative scientific research and the value-laden sphere of societal needs, preferences and decision-making situations. This, in turn, is understood here as a contribution to a more sustainable scientific practice. We illustrate the two elements of SC-optimization of products and processes as well as including the societal aspect-with the examples of environmental chemistry, green chemistry and the environmental assessment of chemical products. While considerable progress has been made in these fields, the societal aspect of SC remains to be recognized more fully in all branches of chemical research. One prerequisite for this is the inclusion of SC into chemical education from the very beginning.
TL;DR: This work clarifies the chemical nature of the brachial organ exudate and suggests a possible mode of action underlying the noxious effects of slow loris bites.
Abstract: Bites inflicted on humans by the slow loris (Nycticebus coucang), a prosimian from Indonesia, are painful and elicit anaphylaxis. Toxins from N. coucang are thought to originate in the brachial organ, a naked, gland-laden area of skin situated on the flexor surface of the arm that is licked during grooming. We isolated a major component of the brachial organ secretions from N. coucang, an approximately 18 kDa protein composed of two 70-90 amino-acid chains linked by one or more disulfide bonds. The N-termini of these peptide chains exhibit nearly 70% sequence similarity (37% identity, chain 1; 54% identity, chain 2) with the two chains of Fel d 1, the major allergen from the domestic cat (Felis catus). The extensive sequence similarity between the brachial organ component of N. coucang and the cat allergen suggests that they exhibit immunogenic cross-reactivity. This work clarifies the chemical nature of the brachial organ exudate and suggests a possible mode of action underlying the noxious effects of slow loris bites.