Interspecific variation in thermal denaturation of proteins in the congeneric musselsMytilus trossulus andM. galloprovincialis: evidence from the heat-shock response and protein ubiquitination

The genetic population structure of the precominant zooplankter, the copepod Calanus finmarchicus (Gunnerus), was examined to determine whether genetically distinct populations exist in the Gulf of Maine. C. finmarchicus was sampled in three regions of the Gulf of Maine (Great South Channel, spring 1989; northern Gulf of Maine, winter 1990; Great South Channel and Georges Bank, spring 1990). Copepods from seven locations in the Great South Channel, five in the northern Gulf of Maine and four on or near Georges Bank were assayed for allozyme variation and mitochondrial DNA variation of amplified 16S rRNA and cytochrome b genes. Restriction fragment length polymorphism (RFLP) analyses of both mitochondrial DNA genes revealed no variation among any of the individuals assayed. Analysis of five polymorphic allozyme loci revealed that genetic variation among the three geographic regions was low, and genetic identities were high between all locations (I>0.97). Most of the genetic variation was among locations regardless of region. Chi-square tests were used to examine genetic similarity between specific pairs of locations within and between regions. In the northern Gulf of Maine, genetic homogeneity occurred over larger spatial scales (hundreds of km) than in either the Great South Channel or Georges Bank (tens of km). Only copepods from the Bay of Fundy and Nova Scotian Shelf locations were genetically distinct from Wilkinson Basin copepods at two loci. Copepod populations from the northern locations may have been partially isolated or they may represent immigrant populations (e.g., from the Gulf of St. Lawrence). Several pairs of locations were genetically distinct at one or more loci in the two southern regions. Differences between locations in these regions may represent distinct populations advected into the areas at different times or from different sources (e.g., genetic variation may represent a mixture of genetically distinct northern and southern copepod populations). These results suggest extensive gene flow among populations of C. finmarchicus in the Gulf of Maine with some evidence of genetic population subdivision near the Gulf's northeastern and southern boundaries.     

Main nutrient compounds in food bodies of Mexican <Emphasis Type="Italic">Acacia</Emphasis> ant-plants

Summary. Myrmecophytic plants use obligate ant mutualists as a constitutive indirect defence mechanism. These plants often produce cellular food bodies (FBs) to nourish their resident ants. Lipids, proteins, and even highly specialised compounds such as glycogen have been reported from FBs, but detailed chemical analyses of FB composition have so far been presented only for Southeast Asian Macaranga and Central American Piper myrmecophytes. Here we report the chemical composition of FBs of five myrmecophytic Acacia (Fabaceae) species from Mexico using HPLC (carbohydrates and proteins) and GC-MS (lipids). Feeding experiments revealed no hints on any use of external food sources by the inhabiting Pseudomyrmex ants. These ants obviously rely completely on FBs and extrafloral nectar provided by their hosts. The total content of nutrients in Acacia FBs was 15-25% of FB dry mass, being much lower than in Macaranga or Piper FBs. Proteins were dominating (8-14 % dm) in Acacia FBs and thus were present in higher amounts than in Macaranga FBs, yet in lower amounts than in Piper. Lipids contributed 1-9 % of dry mass, showing a lower proportion than in FBs of Macaranga or Piper. Carbohydrates made up 3-11 % dm, reaching in most Acacia species the same range as observed in Macaranga and in Piper FBs. Water content was 18-24 % of FB fresh mass, and structural tissue obviously made up a much higher proportion in Acacia FBs than in Macaranga or Piper FBs. Both characters might represent an adaptation to producing FBs unprotected at the leaf tips under dry conditions. Acacia FBs contain all amino acids and all fatty acids that are considered essential for insects, and their contents of lipids and proteins are higher than in the leaves from which they are ontogenetically derived. This indicates a putatively adaptive enrichment of nutritionally valuable compounds in structures functioning as ant-food.     

Soil microarthropods (Acari,Collembola) from beach and dune: characteristics and ecosystem context

Soil microarthropods (Acari, Collembola) were analyzed along transects from shore to brown dune in two sandy coastal sites of the North Sea (Jutland, Denmark, and Spiekeroog, East Frisian island, Germany). Predatory mites (Acari: Gamasina) and Collembola were determined to species. The Jutland and the Spiekeroog sites each yielded 22 Gamasina species, 10 of which are common to both areas. Collembola were identified from the Spiekeroog samples only (also 22 species). Largest mite abundances were found in Jutland in primary dunes (419 tsd. ind./m²) and on Spiekeroog in old brown dunes (314 tsd.ind./m²). Compared to the mites, Collembola abundances are low, with maxima of 77 tsd.ind./m² in Jutland (yellow dune) and only 18 tsd. ind./m² on Spiekeroog (old vellow dune). The communities of predatory mites (Gamasina) and Collembola along transects from shore inland to brown dune are quite specific. High similarities are found for the predatory mites between the specific dune sites of the two North Sea areas, particularly for yellow dune. Additionally, preliminary data are presented for the southern Baltic Coast. The findigns are discussed in a broader context. Arguments focus on conservation and biogenic dune stabilization.     

Development of new dunes in the Dutch Delta: nature compensation and ‘building with nature’

A new dune area was constructed by beach and foreshore nourishments along the Delfland Coast in the southwestern Netherlands. The new area is intended to be a compensation for losses of existing high quality dunes in nearby areas, due to the use/construction of Maasvlakte 2, the new harbour extension of Rotterdam opening in 2013. The target habitats for compensation include dry grey dunes and moist dune valley grassland. Due to the habitat type, the nourished material had to have a special character. The nourishment was carried out according to a special design and initial development of the new area had to follow certain pathways. In order to meet the compensation requirements in time. Careful monitoring is done to assess whether development of the new habitat is taking place in the direction of the desired target habitats. This paper reports on the construction of the new area and on the first years of development and monitoring. The monitoring mainly concerns development of the abiotic landscape elements, geomorphology, groundwater and soils. The lessons learned from this area are discussed in the light of the development of other recent young nature areas in the sandy Dutch delta coast. This gives new insights for coastal management in general in the context of building with nature.     

The making of fetal surgery

Fetal diagnosis prompts the question for fetal therapy in highly selected cases. Some conditions are suitable for in utero surgical intervention. This paper reviews historically important steps in the development of fetal surgery. The first invasive fetal intervention in 1963 was an intra-uterine blood transfusion. It took another 20 years to understand the pathophysiology of other candidate fetal conditions and to develop safe anaesthetic and surgical techniques before the team at the University of California at San Francisco performed its first urinary diversion through hysterotomy. This procedure would be abandoned as renal and pulmonary function could be just as effectively salvaged by ultrasound-guided insertion of a bladder shunt. Fetoscopy is another method for direct access to the feto-placental unit. It was historically used for fetal visualisation to guide biopsies or for vascular access but was also abandoned following the introduction of high-resolution ultrasound. Miniaturisation revived fetoscopy in the 1990s, since when it has been successfully used to operate on the placenta and umbilical cord. Today, it is also used in fetuses with congenital diaphragmatic hernia (CDH), in whom lung growth is triggered by percutaneous tracheal occlusion. It can also be used to diagnose and treat urinary obstruction. Many fetal interventions remain investigational but for a number of conditions randomised trials have established the role of in utero surgery, making fetal surgery a clinical reality in a number of fetal therapy programmes. The safety of fetal surgery is such that even non-lethal conditions, such as myelomeningocoele repair, are at this moment considered a potential indication. This, as well as fetal intervention for CDH, is currently being investigated in randomised trials. Copyright © 2010 John Wiley & Sons, Ltd.     

The role of archaeophytes and neophytes in the Dutch coastal dunes

The position of alien plant species in the Dutch coastal dune vegetation is evaluated considering 12 archaeophytes and 20 neophytes (including one moss), all of widespread occurrence in the coastal area of the Netherlands. Almost all archaeophytes have become part of natural vegetation types. Open scrub communities, in particular Hippophae rhamnoides-Sambucus nigra scrub at the leeside of the outer dunes, and calciphilous moss-dominated pioneer vegetation are relatively rich in archaeophytes. Among neophyte vascular species a contrast is apparent between herbaceous and woody species. The majority of herbaceous neophytes are characteristic of man-disturbed habitats and are only infrequently observed in natural vegetation types. However, woody species (as well as the moss Campylopus introflexus) have entered into natural vegetation on a large scale and behave in an invasive way.