Biofilms: the matrix revisited

Microbes often construct and live within surface-associated multicellular communities known as biofilms. The precise structure, chemistry and physiology of the biofilm all vary with the nature of its resident microbes and local environment. However, an important commonality among biofilms is that their structural integrity critically depends upon an extracellular matrix produced by their constituent cells. Extracellular matrices might be as diverse as biofilms, and they contribute significantly to the organization of the community. This review discusses recent advances in our understanding of the extracellular matrix and its role in biofilm biology.     

Macrobenthos of the subtidal Wadden Sea: revisited after 55 years

During the years 1923–1926 Hagmeier & Kändler (1927) sampled the macrofauna of subtidal shallows and channels of the Wadden Sea close to the Island of Sylt (German Bight, North Sea). Reinvestigating this study area in 1980, a substantially altered faunal composition was recorded. An approach is made to quantify the comparison in terms of abundance, species richness and diversity of invertebrate taxa. Human interference is assumed to be responsible for the major changes. Natural oyster beds have been overexploited and the local population ofOstrea edulis has been driven to extinction. Subsequently, mussels(Mytilus edulis) spread in the entire region, promoted by shell fishery. Particularly barnacles and many polychaetes took advantage of the expansion of mussel banks which is substantiated by correlation analysis. Reefs of the colonial polychaeteSabellaria spinulosa stood in the way of shrimp trawling and became destroyed together with the associated fauna. A subtidalZostera marina bed was wiped out in 1934 by a natural epidemic disease but never succeeded in reestablishing itself. The associated fauna disappeared. Large epibenthic predators and scavengers (crabs, snails and starfish) survived all these changes. The total number of species remained approximately at the same level but molluscs experienced losses and polychaetes diversified. Overall abundance increased with a disproportionately large share of a few species(Mytilus edulis, Balanus crenatus, Cerastoderma edule, Scoloplos armiger). The subtidal fauna of the Wadden Sea proved to be vulnerable to human disturbance; thus, the present community can no longer be viewed as the outcome of entirely natural processes.     

Macrobenthic turnover in the subtidal Wadden Sea: The Norderaue revisited after 60 years

The benthic macrofauna of a tidal inlet in the northern Wadden Sea was sampled with grab and dredge in 1924–1926 (Hagmeier & Kändler, 1927), and again in 1985 and 1986. The comparison of surveys from consecutive years, as well as observations from an adjacent area, are employed to separate spurious from real long-term changes. Several epibenthic species of the 1920s became rare or absent in the 1980s. Oyster beds and reefs of the colonial polychaeteSabellaria spinulosa have disappeared completely. On the other hand, mussel beds have extended their range, and the abundance of mobile infauna has increased. The total number of species has remained approximately the same. Compared to surveys from consecutive years, the 60-year interval has doubled the species turnover rate, and has decreased the similarity in relative abundances by one third. The observed losses are best explained by the impact of dredging and trawling on the benthic fauna, while gains seem to indicate coastal eutrophication.     

Unraveling the organization of the internal nuclear matrix: RNA-dependent anchoring of NuMA to a lamin scaffold

Using quantitative immunoelectron microscopy we show here that when the nuclear matrix is isolated from rat hepatocytes in the presence of an inhibitor of RNase activity both lamins and the nuclear mitotic apparatus protein (NuMA) preferentially localize within the electron-dense domains of the internal nuclear matrix (INM). After RNA digestion NuMA undergoes a sharp depletion, while labeling by an antibody against lamins A and C within the electron-transparent regions increases, suggesting that a subset of lamin epitopes is masked by the interaction with RNA. We were able to explain this result by visualizing for the first time a thin web of lamin protofibrils which connects the electron-dense regions. Confirmation of these changes has been obtained by immunoblot analysis and confocal microscopy. As RNA digestion results both in the release of NuMA and in the collapse of the INM, we propose that a fraction of nuclear RNA brings about the association of NuMA islands with a lamin scaffold and that this interaction is required to maintain the latter in a state of high molecular dispersion.     

Genetic variation of Zoarces viviparus: six populations revisited after about 35 years

Totally, 417 eelpouts from six localities were collected in November-December 2007. Among these, 314 were females and from 246 of these females, one offspring was collected. The selected populations were also studied 36-38 years ago with the same technique, horizontal starch gel electrophoresis. The same enzymes were analysed at that time and now, but additional enzymes were analysed in the samples collected now, totally five enzymes representing 10 loci. A strong congruence in the genetic composition was found between the samples collected 36-38 years ago and those collected in 2007. No effect of pollutants in the environment was seen on the genetic variation by means of isozymes, but deformed offspring was observed and furthermore at one locality a high frequency of not pregnant females in the sample was observed.     

Kabat database and its applications: 30 years after the first variability plot

The Kabat Database was initially started in 1970 to determine the combining site of antibodies based on the available amino acid sequences at that time. Bence Jones proteins, mostly from human, were aligned, using the now-known Kabat numbering system, and a quantitative measure, variability, was calculated for every position. Three peaks, at positions 24-34, 50-56 and 89-97, were identified and proposed to form the complementarity determining regions (CDR) of light chains. Subsequently, antibody heavy chain amino acid sequences were also aligned using a different numbering system, since the locations of their CDRs (31-35B, 50-65 and 95-102) are different from those of the light chains. CDRL1 starts right after the first invariant Cys 23 of light chains, while CDRH1 is eight amino acid residues away from the first invariant Cys 22 of heavy chains. During the past 30 years, the Kabat database has grown to include nucleotide sequences, sequences of T cell receptors for antigens (TCR), major histocompatibility complex (MHC) class I and II molecules and other proteins of immunological interest. It has been used extensively by immunologists to derive useful structural and functional information from the primary sequences of these proteins. An overall view of the Kabat Database and its various applications are summarized here. The Kabat Database is freely available at http://immuno.bme.nwu.edu     

NuMA is a component of an insoluble matrix at mitotic spindle poles

NuMA associates with microtubule motors during mitosis to perform an essential role in organizing microtubule minus ends at spindle poles. Using immunogold electron microscopy, we show that NuMA is a component of an electron-dense material concentrated at both mitotic spindle poles in PtK1 cells and the core of microtubule asters formed through a centrosome-independent mechanism in cell-free mitotic extracts. This NuMA-containing material is distinct from the peri-centriolar material and forms a matrix that appears to anchor microtubule ends at the spindle pole. In stark contrast to conventional microtubule-associated proteins whose solubility is directly dependent on microtubules, we find that once NuMA is incorporated into this matrix either in vivo or in vitro, it becomes insoluble and this insolubility is no longer dependent on microtubules. NuMA is essential for the formation of this insoluble matrix at the core of mitotic asters assembled in vitro because the matrix is absent from mitotic asters assembled in a cell-free mitotic extract that is specifically depleted of NuMA. These physical properties are consistent with NuMA being a component of the putative mitotic spindle matrix in vertebrate cells. Furthermore, given that NuMA is essential for spindle pole organization in vertebrate systems, it is likely that this insoluble matrix plays an essential structural function in anchoring and/or stabilizing microtubule minus ends at spindle poles in mitotic cells.     

Reconstruction of a posttraumatic ear defect using tissue expansion: 30 years after Neumann

A two-stage method suitable for reconstructing the lower part of the auricle and using an advancement-rotation flap of expanded cervical and postauricular skin is described. Expander shape and capacity should be selected after careful consideration of available donor sites and the amount of additional tissue required for reconstruction.     

Science in China: 30 years on

Three decades after introducing market reforms and opening up to the rest of the world, China has become a major economic power. As the country prepares to show the world its sporting might, its competitiveness in life sciences may still need a boost.     

Attachment point theory revisited: the fouling response to a microtextured matrix

This paper examines attachment point theory in detail by testing the fouling attachment of several fouling groups to a microtextured matrix. Static bioassays were conducted on polycarbonate plates with nine equal regions, comprising eight scales of microtexture (4-512 microm) and one untextured region. The microtextures examined were continuous sinusoidal ridges and troughs of defined height and width. Attachment over the microtextured plates was examined for the diatom Amphora sp., the green alga Ulva rigida, the red alga Centroceras clavulatum, the serpulid tube worm Hydroides elegans and the bryozoan Bugula neritina. It was found that the size of the microtexture in relation to the size of the settling propagules/larvae was important in the selection of attachment sites. Attachment was generally lower when the microtexture wavelength was slightly smaller than the width of the settling propagules/larvae and increased when the wavelength was wider than their width. The effect of attachment points was weak for small motile microfoulers (Amphora sp. and U. rigida) (7 microm), strong for large macrofouling larvae (H. elegans and B. neritina) (129-321 microm) and non-existent for the non-motile algal spores (C. clavulatum) (37 microm). This study reinforces the potential of using attachment points to develop surfaces with increased fouling resistance or, alternatively, surfaces which promote the attachment of selected target sizes of motile propagules or larvae.     

NPY and stress 30 years later: the peripheral view

Almost 30 years ago, neuropeptide Y (NPY) was discovered as a sympathetic co-transmitter and one of the most evolutionarily conserved peptides abundantly present all over the body. Soon afterward, NPY's multiple receptors were characterized and cloned, and the peptide's role in stress was first documented. NPY has proven to be pivotal for maintaining many stress responses. Most notably, NPY is known for activating long-lasting vasoconstriction in many vascular beds, including coronary arteries. More recently, NPY was found to play a role in stress-induced accretion of adipose tissue which many times can lead to detrimental metabolic changes. It is however due to its prominent actions in the brain, one of which is its powerful ability to stimulate appetite as well as its anxiolytic activities that NPY became a peptide of importance in neuroscience. In contrast, its actions in the rest of the body, including its role as a stress mediator, remained, surprisingly underappreciated and not well understood. Our research has focused on that other, "peripheral" side of NPY. In this review, we will discuss those actions of NPY on the cardiovascular system and metabolism, as they relate to adaptation to stress, and attempt to both distinguish NPY's effects from and integrate them with the effects of the classical stress mediators, glucocorticoids, and catecholamines. To limit the bias of someone (ZZ) who has viewed the world of stress through the eyes of NPY for over 20 years, fresh insight (DH) has been solicited to more objectively assess NPY's contributions to stress-related diseases and the body's ability to adapt to stress.     

The isolated hepatocyte preparation: 30 years on

A method for the preparation of intact rat hepatocytes in high yield was first described in 1969. The procedure involved digestion of hepatic tissue by perfusion of the liver with crude collagenase; later, purified collagenase without other enzymic additions was shown to be ineffective. Recently it has been discovered that the combination of purified collagenase plus elastase is superior to crude collagenase in that it consistently provides high yields of undamaged hepatocytes. The isolated hepatocyte preparation has proved particularly useful for the study of mechanisms responsible for long-range interactions within the cell. These can be studied over prolonged time courses and in the presence of graded concentrations of specific inhibitors. Studies of this kind have demonstrated a close relationship between cytoplasmic metabolic flows and mitochondrial forces and have also revealed that the cytoplasmic and mitochondrial free NAD-linked redox potentials are maintained by energy-dependent reactions.     

The Empire Strikes Back: 30 years on

The Empire Strikes Back was a landmark text in the formation and transformation of ethnic and racial studies in Britain. With issues of race, migration, nation and inequality starkly back on the current political and public agenda, this review article reflects on the continued significance of the book's insights and challenges for contemporary race politics in the UK.     

Making a difference: 30 years of TDR

When the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) was established in the mid-1970s, it represented an innovative institutional formula in terms of its structure and the manner in which scientists were convened from both developed and developing countries to address some of the world's most neglected parasitic diseases. A review of TDR's historical record sheds light not only on some important milestones in tropical-disease research, but also on how future challenges could be approached and hopefully surmounted.