Incorporation of 14CO2, into cardenolide and sapogenin steroids of Digitalis purpurea

The relative rates of biosynthesis of cardenolide and sapogenin steroids of Digitalis purpurea were estimated by their uptake of ¹⁴CO₂. The incorporation of label into both groups, although initially slow, indicated that biosynthesis occurs even at the end of the growing season. The sapogenins were produced more rapidly than the cardenolides at this stage of plant development. Within the group of sapogenins, digitogenin, the trihydroxy compound, was produced at a greater rate than the dihydroxy steroid gitogenin. In the case of the cardenolides, the trihydroxy gitoxigenin was produced at a slower rate than the dihydroxy digitoxigenin.     

Nine decades of fish movement research in southern Africa: a synthesis of research and findings from 1928 to 2014

Unprecedented concern over the biological effects of over-exploitation, together with rapid technological advances in biotelemetry, have provided the impetus for much research, on a global scale, into the movement of marine animals. We reviewed 101 marine and estuarine fish movement studies from southern Africa, published from 1928 to 2014, with the aim of synthesising research trends and findings. Trends showed an increasing emphasis on fish movement research in publications in the sub-tropical and warm-temperate biogeographic regions along the south and east coasts of southern Africa. Although 63 % of publications featured only marine studies, research into fine-scale habitat use in estuaries has been on the increase, concomitant with increasing accessibility of biotelemetry. Overall, 26 families were identified in the surveyed literature with regionally endemic sparids featuring in 32 % of the publications. Ten movement themes were identified in the surveyed literature, including broad-scale movement patterns, which featured in 68 % of studies, followed by fine-scale habitat usage (33 %) and protected areas (26 %). The most prominent phenomenon, emerging from this research, is that of partial migration, which describes the occurrence of resident and migratory behaviour within a coexisting animal population. Substantial progress has also been made in unravelling the complexities of fine-scale habitat usage in marine reserves and in estuaries. While this knowledge has enabled more effective management of South Africa’s multi-user, multi-species fisheries, focus should now be directed at improving our understanding of the commonalities in movement behaviour, the associated driving forces behind this behaviour and the nature of movement across reserve boundaries.     

Meaning in Nature: Organic Manufacture?

The paper examines Marcello Barbieri’s (2007) Introduction to Biosemiotics. Highlighting debate within the biosemiotic community, it focuses on what the volume offers to those who explain human intellect in relation to what Turing called our ‘physical powers.’ In scrutinising the basis of world-modelling, parallels and contrasts are drawn with other work on embodied-embedded cognition. Models dominate biology. Is this a qualitative fact or does it point to biomechanisms? In evaluating the 18 contributions, it is suggested that the answers will shape the field. First, they will decide if biochemistry and explanatory reduction can be synergised by biosemantics. Second, they will show if our intellectual powers arise from biology. Does thinking use—not a language faculty—but what Marko? and colleagues call semiosis by the living? Resolution of such issues, it is suggested, can change how we view cognition. Above all, if the biomechanists win the day, cultural models can be regarded as extending natural meaning. On such a view, biomechanisms prompt us to act and perceive as we model our own natural models. This fits Craik’s vision: intellect gives us the alphanumerical ‘symbols’ that allow thoughts to have objective validity. For the biomechanist, this is explained—not by brains alone—but, rather, by acting under the constraints of historically extended sensoria.     

Causes and consequences of human induced impacts on a ubiquitous estuary-dependent marine fish species

Decreasing populations of common estuary-associated marine fishes are being documented globally and red flags associated with such declines are often ignored due to the high relative abundance of these species when compared to more rare and threatened taxa. The Cape stumpnose Rhabdosargus holubi (Steindachner 1881) is an abundant and widespread southern African sparid that is dependent on estuaries as a primary nursery area. Historical and current information on the species is comprehensive and the accumulated evidence strongly suggests that this ubiquitous fish is under pressure, mainly due to degradation of estuaries and associated catchments, increasing fishing pressures from recreational and subsistence anglers, habitat loss relating to reduced submerged macrophyte areas in many systems, industrial and agricultural pollution, infrastructural developments in and around estuaries, and climate change. In particular, the temporary loss of Lake St Lucia, which accounts for approximately 50% of the estuarine surface area in South Africa, has drastically reduced the nursery area availability for R. holubi on the subcontinent. Overall we present strong evidence to support the hypothesis that present-day stocks of R. holubi are much smaller than those in the pristine state and that urgent management measures need to be considered and implemented to prevent current depleted populations of the species from declining further.     

Regulatory links between imprinted genes: evolutionary predictions and consequences

Genomic imprinting is essential for development and growth and plays diverse roles in physiology and behaviour. Imprinted genes have traditionally been studied in isolation or in clusters with respect to cis-acting modes of gene regulation, both from a mechanistic and evolutionary point of view. Recent studies in mammals, however, reveal that imprinted genes are often co-regulated and are part of a gene network involved in the control of cellular proliferation and differentiation. Moreover, a subset of imprinted genes acts in trans on the expression of other imprinted genes. Numerous studies have modulated levels of imprinted gene expression to explore phenotypic and gene regulatory consequences. Increasingly, the applied genome-wide approaches highlight how perturbation of one imprinted gene may affect other maternally or paternally expressed genes. Here, we discuss these novel findings and consider evolutionary theories that offer a rationale for such intricate interactions among imprinted genes. An evolutionary view of these trans-regulatory effects provides a novel interpretation of the logic of gene networks within species and has implications for the origin of reproductive isolation between species.     

Flight areas of British butterflies: assessing species status and decline

Geographical range size is a key ecological variable, but the consequences of measuring range size in different ways are poorly understood. We use high-resolution population data from British butterflies to demonstrate that conventional distribution maps, widely used by conservation biologists, grossly overestimate the areas occupied by species and grossly underestimate decline. The approximate flight areas occupied by 20 out of 45 colonial British species were estimated to cover a median of only 1.44% of the land surface within occupied regions. Common species were found to be declining faster than conventional distribution maps suggest: common and rare species had no significant difference in their population-level rates of extinction. This, combined with the log-normal form of the range-size frequency distribution, implies that species-level extinction rates may accelerate in the medium to long term. Population-level conservation is a matter of great urgency for all species, not just for the rarest.     

Detecting decline in a formerly widespread species: how common is the common blue butterfly Polyommatus icarus?

Grid square distribution maps have been used widely to measure rates of decline and target conservation resources. However, common species that may have many populations per grid square can decline substantially from within squares without being lost from entire squares. In order to quantify this process, fine scale population and habitat data have been collected for the common blue butterfly Polyommatus icarus in a 35 km² area of fragmented landscape in north Wales. Present day habitat associations, determined from over 2000 transect walks, combined with data on historical and present day habitat distributions reveal that the species has declined by about 74% since 1901. Similar data concerning the species major host plant Lotus corniculatus indicate a decline of 46%. Based on 1 km² grid maps, neither species have been assessed as declining at all. These results suggest that apparently 'common' species may have declined just as much as many of Britain's rare species: using present methods of assessment these declines are undetected.     

Investigating Maturity Onset Diabetes of the Young

Maturity Onset Diabetes of Young (MODY) is a monogenic and autosomal dominant form of diabetes mellitus with onset of the disease often before 25 years of age. It is due to dysfunction of pancreatic ß cells characterised by non-ketotic diabetes and absence of pancreatic auto-antibodies. It is frequently mistaken for type 1 or type 2 diabetes mellitus. Diagnosis of MODY is important as the GCK subtype has better prognosis and may not require any treatment. Subtypes HNF1A and HNF4A are sensitive to sulfonylureas, however diabetes complications are common if not treated early. Moreover, there is genetic implication for the patient and family. Rare MODY subtypes can be associated with pancreatic and renal anomalies as well as exocrine dysfunction of the pancreas. So far there are six widely accepted subtypes of MODY described but the list has grown to nine. Although the majority of diabetes mellitus in youth remains type 1 and the incidence of type 2 is rising, MODY should be considered in patients with non-ketotic diabetes at presentation, and in patients with a strong family history of diabetes mellitus without pancreatic auto-antibodies. Furthermore the diagnosis must be confirmed by molecular studies. With advancement in genomic technology, rapid screening for MODY mutations will become readily available in the future.     

Mikrozephaliesyndrome und geistige Behinderung

Clarification of the cause of mental retardation, which has a prevalence of 2–3%, is a common reason for genetic consultation. On the basis of the cardinal sign of microcephaly, which also has a prevalence of 2–3%, an overview on different conditions with developmental delay/mental retardation is given according to the mode of inheritance. The current version of the Winter–Baraitser Dysmorphology Database lists 558 conditions with the combination of microcephaly and developmental delay/mental retardation. This makes clear that the following overview gives only a limited look at the comprehensive field of clinical genetics/dysmorphology.     

Acidocalcisomen,Mitosomen und Apicoplasten. Neu entdeckte Zellorganellen

Three new, membrane‐bounded organelles were detected in the last decade. Acidocalcisomes which occur in pro‐ and eukaryotes are acidic and store calcium, and further also phosphate, oxygen, magnesium, zink, sodium, potassium, and iron. Furthermore, they are engaged in osmoregulation, pH‐ and Ca²⁺‐homeostasis. Mitosomes are strongly reduced mitochondria of different parasitic protists, which were previously grouped as primarily mitochondria‐free organisms. Apicoplasts are the strongly reduced plastids of the parasitic apicomplexans (formerly sporozoa). They are a target for the development of new drugs, e.g. against the cause of malaria, Plasmodium.