Rat monoclonal antibodies to rabbit and human serum low-density lipoprotein.

A total of 16 hybrid myeloma clones secreting monoclonal antibodies (McAb) to rabbit or human serum low-density lipoprotein (LDL) were derived from the fusion of spleen cells from LOU or DA rats immunized with rabbit or human LDL and the rat myeloma lines Y3 Ag1.2.3 or YB2/0. Anti-(rabbit LDL) McAb showed limited reactivity with LDL from human, rhesus-monkey, rat and mouse serum. Six out of seven anti-(human LDL) McAb reacted with rhesus-monkey LDL, and only one showed partial cross-reaction with rabbit LDL. Binding-competition experiments indicated that the epitopes recognized by the anti-(rabbit LDL) IgG could be grouped into two major clusters: McAb in the first cluster reacted either with apo-(lipoprotein B-100) (apoB-100) and apo-(lipoprotein B-74) (apoB-74) or with apoB-100 but not with apo-(lipoprotein B-48) (apoB-48), the lower-Mr form of apoB of intestinal origin; the McAb in the second cluster all reacted with apoB-48 in addition to apoB-100 or apoB-100 and apoB-74. The six anti-(human LDL) IgG bound to separate epitopes on LDL. Further data on the epitope specificity of these McAb were obtained by antibody blotting after partial proteolysis of apoB-100 with trypsin or staphylococcal V8 proteinase, and the data confirmed the results obtained with the binding-competition experiments. One McAb to rabbit LDL inhibited the binding of LDL to the fibroblast LDL receptor (50% inhibition at a McAb/LDL molar ratio of 10). A similar result was produced by two other McAb at higher concentrations of antibody.     

Ecology and conservation of the crowned lemur, Lemur coronatus, at Ankarana, n. Madagascar. With notes on Sanford's lemur, other sympatrics and subfossil lemurs

Forests of Ankarana limestone massif in northern Madagascar support one of the largest and least disturbed populations of Crowned Lemurs, Lemur coronatus. This paper reports a preliminary study of the ecology of this species in the Ankarana Special Reserve conducted at the end of the dry season in 1986, with additional information collected a year later. Crowned Lemurs occur in very high densities in the semi-deciduous canopy forest and this probably represents a dry season refuge for the species. They also use more open habitats, including sparsely vegetated limestone and degraded forest. Sanford's Lemur, Lemur fulvus sanfordi, also inhabits the Ankarana forests but is most abundant in degraded habitats. Crowned and Sanford's Lemurs had similar patterns of activity, which included nocturnal travelling and feeding bouts. Crowned Lemurs proved to be unusual among Lemur species in displaying low spatial troop cohesion and a lack of obvious troop hierarchy. Stronglyoides-like enteric helminths infested about one third of Crowned Lemurs but were apparently not causing disease. Crowned Lemurs fall prey to the Fosa, Cryptoprocta ferox, and the young possibly also to the largest raptors. A total of seven living lemur species (including the very rare Propithecus diadema perrieri and Daubentonia madagascariensis) were confirmed at Ankarana by the authors, and three further species have been reported by other observers. In addition to these ten extant lemurs, four subfossil species have been discovered: three of them (Hapalemur simus, Palaeopropithecus and Mesopropithecus) by the authors. The possibility that all 14 lemurs were once sympatric is discussed. For the present, the lemurs of Ankarana are protected from hunting by local taboo. Nevertheless they are under severe threat from habitat destruction, despite Ankarana's Special Reserve status. Given the very restricted distributions of Crowned and Sanford's Lemurs, both must be considered as threatened with extinction.     

A study of growth form in genets of Trifolium repens L. as affected by intra- and interplant contacts

Summary The stolon apices of genets of Trifolium repens were mapped in the field, and the distance moved by each apex eight days after mapping was measured. The spatial distribution of the apices was investigated using the Voronoi polygon construct. The spacing of apices was shown to differ between genets, and to be influenced by the proximity of neighbouring genets. The rate of extension of stolons was positively correlated with polygon area. The differences observed were interpreted in terms of differences in the positions of genets along the phalanx-guerilla continuum of growth forms. Mechanisms which may promote the intermingling of genets are discussed.     

Immobilization of Heavy Metals in Soil Using Natural and Waste Materials for Vegetation Establishment on Contaminated Sites

Contaminated land is increasingly becoming an important issue worldwide. Many contaminants are persistent in soil for a large number of years. With the increase in public awareness regarding the consequences of contaminated soil, many researchers are concentrating on developing cost-effective and socially acceptable soil remediation technologies. Soils of many sites, which have been left derelict after industrial decline, harbor a broad suite of metal and organic contaminants. Land where such contaminants are deemed to pose a significant risk to receptors is considered contaminated under modern guidance. Remediation to break identified pollutant linkages would precede reclamation and plant establishment. One approach to break the pollutant receptor linkage is to utilize materials that effectively create soil conditions that immobilize contaminants whilst providing essential plant growth properties in terms of nutrition and water holding capacity. Materials that may achieve this include: 1) composts derived from materials such as sewage sludges and other municipal sources; 2) natural or synthetic zeolites; or 3) industrial by-products such as red-mud or other iron-rich materials such as iron grit or iron oxyhydroxides. Remediation techniques that utilize such materials may be cost-effective compared to more traditional methods and may effectively divert materials from the waste stream and could thereby make a dual contribution to sustainable development.     

Streptomyces as symbionts: an emerging and widespread theme?

Streptomyces bacteria are ubiquitous in soil, conferring the characteristic earthy smell, and they have an important ecological role in the turnover of organic material. More recently, a new picture has begun to emerge in which streptomycetes are not in all cases simply free-living soil bacteria but have also evolved to live in symbiosis with plants, fungi and animals. Furthermore, much of the chemical diversity of secondary metabolites produced by Streptomyces species has most likely evolved as a direct result of their interactions with other organisms. Here we review what is currently known about the role of streptomycetes as symbionts with fungi, plants and animals. These interactions can be parasitic, as is the case for scab-causing streptomycetes, which infect plants, and the Streptomyces species Streptomyces somaliensis and Streptomyces sudanensis that infect humans. However, in most cases they are beneficial and growth promoting, as is the case with many insects, plants and marine animals that use streptomycete-produced antibiotics to protect themselves against infection. This is an exciting and newly emerging field of research that will become increasingly important as the search for new antibiotics switches to unusual and under-explored environments.     

Consequences of fisheries-induced evolution for population productivity and recovery potential

Fisheries-induced evolution has become a major branch of the research on anthropogenic and contemporary evolution. Within the conservation context, fisheries-induced evolution has been hypothesized to negatively affect the persistence and recovery potential of depleted populations, but this has not been explicitly investigated. Here, we investigate how fisheries-induced evolution of Atlantic cod (Gadus morhua L.) life histories affects per capita population growth rate, a parameter negatively correlated with extinction risk. We simulate the evolutionary and ecological dynamics of a cod population for a 100 year period of size-selective harvesting, followed thereafter by 300 years of recovery. To evaluate the relative importance of harvest-induced evolution, we either allowed life histories to evolve during and after the fishing period, or we assumed that fisheries-induced evolution was absent. Population growth rates did not differ appreciably between the evolutionary and non-evolutionary simulation scenarios, despite the emergence of rather pronounced differences in life histories. The underlying reason was that in the absence of fishing the cumulative lifetime reproductive outputs were very similar among differing life histories. The results suggest that fisheries-induced evolution might not always have as clear-cut an effect on population growth rate as previously anticipated.     

Role of partial protein unfolding in alcohol‐induced protein aggregation

Proteins aggregate in response to various stresses including changes in solvent conditions. Addition of alcohols has been recently shown to induce aggregation of disease‐related as well as nondisease‐related proteins. Here we probed the biophysical mechanisms underlying alcohol‐induced protein aggregation, in particular the role of partial protein unfolding in aggregation. We have studied aggregation mechanisms due to benzyl alcohol which is used in numerous biochemical and biotechnological applications. We chose cytochrome c as a model protein, for the reason that various optical and structural probes are available to monitor its global and partial unfolding reactions. Benzyl alcohol induced the aggregation of cytochrome c in isothermal conditions and decreased the temperature at which the protein aggregates. However, benzyl alcohol did not perturb the overall native conformation of cytochrome c. Instead, it caused partial unfolding of a local protein region around the methionine residue at position 80. Site‐specific optical probes, two‐dimensional NMR titrations, and hydrogen exchange all support this conclusion. The protein aggregation temperature varied linearly with the melting temperature of the Met80 region. Stabilizing the Met80 region by heme iron reduction drastically decreased protein aggregation, which confirmed that the local unfolding of this region causes protein aggregation. These results indicate that a possible mechanism by which alcohols induce protein aggregation is through partial rather than complete unfolding of native proteins. Proteins 2010. © Wiley‐Liss, Inc.