The impact of commercially available purinergic ligands on purinergic signalling research

Due to the extremely wide-spread expression of purinergic receptors, purinergic signalling has been implicated in numerous physiological and pathophysiological areas. To better understand the involvement of purinergic receptors in such areas, the researcher’s requirement for diverse and varied purinergic receptor ligands has greatly increased. This has generated increased commercial opportunities for life science suppliers, and ultimately, has led to a rapid expansion in the number of commercially available purinergic receptor ligands. The wide-spread availability of ligands to researchers has greatly benefited the scientific community, nurturing the rapid and continued expansion of the purinergic signalling field.

     

The Evolution of Human Probiotics: Challenges and Prospects

Probiotics and Antimicrobial Proteins - In recent years, the intestinal microbiota has been found to greatly influence a number of biological processes important for human health and longevity....     

Ultrafine structure of the integument of the tick Hyalomma asiaticum P. Sch. et E. Schl. in starvation and feeding]

Integument fine structure of H. asiaticum nymphs during their feeding and starvation has been studied. In hungry nymphs hypoderma has an ultrastructure typical for hypodermal cells of arthropods in the intermoulting period and is characterized by a poor development of granular endoplasmic reticulum, small number of mitochondrial and absence of Golgi complexes. The apical surface of the cells is covered with short irregularly scattered microvilli. The cuticle consists of the procuticle, which has a homogenous fine-granular structure, and four-layered epicuticle. During the feeding period hypodermal cells greatly increase in volume and the elements of granular endoplasmic reticulum and metachondria increase in number. Golgi complexes and a variety of apical vesicles have been observed. The number of microvilli on the apical surface increases that is accompanied by a cuticle growth. Procuticle, which is being formed within this period, has a lamellar structure.     

Quantification of cytotoxic hemocytes of Mytilus edulis using a cytotoxicity assay in agar

When a thin layer of agar containing a mixture of erythrocytes and Mytilus hemocytes is prepared on slides, the occurrence of plaques of lysed target cells can be observed around a limited number of hemocytes. These hemocytes remain completely intact cells and are viable as evidenced by their ability to phagocytose target cells and/or to form pseudopods. The number of hemocytes releasing cytotoxic molecules has been shown to vary greatly between different animals. The same holds true for the total number of circulating hemocytes, although no correlation exists between the number of hemocytes in the circulation and the percentage of cytotoxic blood cells.     

Mature egg number influences the behavior of femaleBattus philenor butterflies

Although oviposition behavior of butterflies has been studied extensively, physiological parameters that may affect various aspects of female behavior have been overlooked almost completely. The number of mature eggs carried by a female Battus philenorgreatly affects her behavior at any particular time. Females with many eggs search significantly more for host plants than females with fewer eggs, which tend to rest more. Parameters affecting the number of mature eggs are also studied.     

Cellular models for disease exploring and drug screening

The biopharmaceutical industry has been greatly promoted by the application of drug and disease models, including both animal and cellular models. In particular, the emergence of induced pluripotent stem cells (iPSC) makes it possible to create a large number of disease-specific cells in vitro. This review introduces the most widely applied models and their specialties.     

水稻产量数量性状的遗传调控机制研究进展

粒重、每穗粒数和每株穗数是决定水稻产量的三大要素,也是水稻育种改良的重点．这些性状都是遗传复杂的数量性状．近十年来,水稻数量性状遗传学领域取得了突破性的进展,成功克隆了一批控制水稻产量性状的数量性状位点（QTL）．本文将简要介绍产量性状相关QTL的功能与作用机制．这些研究成果不仅有助于揭示产量性状形成的遗传基础,也将有力推动水稻分子设计育种的进程．     

Transiently beneficial insertions could maintain mobile DNA sequences in variable environments

The maintenance of mobile DNA sequences in clonal organisms has been seen as a paradox. If selfish mobile sequences spread through genomes only by overreplication in transposition, then sexuality is necessary for their spread through populations. The persistence of bacterial transposable elements without obvious dominant selectable markers has previously been explained by horizontal transfer. However, advantageous insertions of mobile DNAs are known in bacteria. Here we model maintenance of an otherwise selfish mobile DNA element in a clonal species in which selection for null mutations occurs during one of two temporally alternating environments. Large areas of parameter space permit maintenance of mobile DNAs where, without selection, they would have gone extinct. Horizontal transfer diminishes, rather than enhances, mean copy number. In finite populations, effective population sizes are greatly reduced by selective sweeps, and mean copy number can be increased as the reduced variance in copy number results in reduced selection.     

The method of pollination with a pollen mixture to obtain interspecific hybrids of plum and cherry

The obtaining of blackthorn×plum hybrids is greatly facilitated by using a pollen mixture of different plum varieties (as compared with pollination by each plum variety separately). This also holds for the backcross to the plum, where the plum is the pollen parent. The cross sand cherry×plum only succeeded when plum pollen was mixed with myrobalan pollen. A number of triple interspecific hybrids has been obtained.     

Socioeconomic inequalities in health in The Netherlands: impact of a five year research programme.

The attention paid to the socioeconomic inequalities in health in the Netherlands has increased greatly in recent years. A national research programme was started in 1989, and among other things, this has increased the yearly number of publications on socioeconomic inequalities in health by about 25%. The programme has increased awareness of inequalities among researchers and policy makers as well as improved the information available on health inequalities and the reasons for them. Cross party agreement on the need to reduce these inequalities has led to a consensus based approach which contrasts with the heavily politicised debate in countries such as the United Kingdom.     

Effect of absolute and relative changes of hematocrit on erythropoiesis in mice

The serial changes of peripheral reticulocytes and marrow erythroid progenitor cells (CFU-e) in mice were monitored under the conditions of absolute or relative changes in red cell mass to study the regulatory mechanism of erythropoiesis. A decreased number of marrow CFU-e and peripheral reticulocytes was observed in the mice with relative polycythemia induced by dehydration as well as in the mice with absolute polycythemia induced by hypertransfusion. On the other hand, a transient increase in the number of marrow CFU-e followed by a gradual increase in the number of peripheral reticulocytes was seen after a considerable amount of exsanguination. Similar stimulatory effects on marrow CFU-e were also observed either by rehydrating the dehydrated mice or by overhydrating the untreated mice to relatively decrease the level of hematocrit. The results suggested that in addition to factors relating to the balance between oxygen supply and requirement, which has been well known, erythropoiesis is greatly affected by hematocrit.     

Colon polyps: a damaged developmental system and a precursor to cancer.

The observation that the attenuated form of adenomatous polyposis coli (AAPC) has a different mutational spectrum in both the adenomatous polyp and the carcinoma than the classical form of APC has led to the hypothesis that AAPC alleles retain some residual APC activity associated with a greatly reduced number of polyps. It is suggested that further progression to carcinoma may be dependent upon either loss of the AAPC allele (loss of heterozygosity), followed by an APC mutation in the wild-type allele, or the occurrence of APC mutations within both the AAPC and wild-type alleles.     

Progress in Irish lower palaeozoic palynology

Knowledge of Lower Palaeozoic palynomorphs in Ireland has improved greatly during the last decade, and acritarchs of most epochs from Vendian to Wenlock, together with Ordovician and Silurian chitinozoa and Silurian miospores, are now known. The present state of knowledge is summarised in terms of a number of distinctive palynological assemblages.     

A new method for RAPD primers selection based on primer bias in nucleotide sequence data

Sequence analysis has proved that decamer nucleotides, used as primers of RAPD (random amplified polymorphic DNA), differ with each other greatly in number of annealing sites in the Arabidopsis thaliana genome. It is called the 'primer bias' by the authors. The biased primers produce a highly variable number of amplicons by polymerase chain reaction (PCR). The number of amplicons is proved to correlate with the number of annealing sites. Therefore, a statistical method is proposed for selecting efficient primers based on the primer bias in the genomic sequence. The method was tested by experiment in A. thaliana genome, and the results demonstrate that the method outperforms routine methods and can substantially increase the efficiency of RAPD methodologies. We also proved that the expressed sequence tags (ESTs) show a highly coincident bias pattern with that of the whole genomic sequence, and can therefore be used to assess efficiencies of primers for species whose genomic sequence data are currently unknown.     

Preparation for disaster

Standardization of county medical society plans for dealing with casualties in disasters would greatly facilitate integration with the state Civil Defense organization. Without such plans there can be no hope of coping with the great number of casualties that would come should this area be attacked. The plan of the Alameda-Contra Costa County Medical Association herein described, has been tested in actual emergency and has been found effective.     

PREPARATION FOR DISASTER—What the Individual Medical Society Can Do

Standardization of county medical society plans for dealing with casualties in disasters would greatly facilitate integration with the state Civil Defense organization.Without such plans there can be no hope of coping with the great number of casualties that would come should this area be attacked.The plan of the Alameda-Contra Costa County Medical Association herein described, has been tested in actual emergency and has been found effective.     

Species invasions exceed extinctions on islands worldwide: a comparative study of plants and birds

Species richness is decreasing at a global scale. At subglobal scales, that is, within any defined area less extensive than the globe, species richness will increase when the number of nonnative species becoming naturalized is greater than the number of native species becoming extinct. Determining whether this has occurred is usually difficult because detailed records of species extinctions and naturalizations are rare; these records often exist, however, for oceanic islands. Here we show that species richness on oceanic islands has remained relatively unchanged for land birds, with the number of naturalizations being roughly equal to the number of extinctions, and has increased dramatically for vascular plants, with the number of naturalizations greatly exceeding the number of extinctions. In fact, for plants, the net number of species on islands has approximately doubled. We show further that these patterns are robust to differences in the history of human occupation of these islands and to the possibility of undocumented species extinctions. These results suggest that species richness may be increasing at subglobal scales for many groups and that future research should address what consequences this may have on ecological processes.     

A quantitative analysis of germ cells and the histone variants in the testes of vitamin A-deficient rats and during subsequent repletion with vitamin A

A quantitative analysis of the different types of germ cells present in the seminiferous tubules of vitamin A-deficient-retinoate maintained rats revealed that the number of pachytene spermatocytes and spermatogonia was greatly reduced in the deficient rats. Spermatids were virtually absent in the deficient tubules which contained mostly spermatogonia and preleptotene spermatocytes along with the Sertoli cells. There was no change in the number of Sertoli cells present in the tubules of deficient rats as compared to that of normal rats. Following supplementation of retinyl acetate to vitamin A-deficient-retinoate maintained rats, there was an immediate thinning of the germinal epithelium resulting from the sloughing off of the damaged spermatocytes which were beyond repair. However, after 12 days of vitamin A supplementation fresh batch of pachytene spermatocytes started appearing while by day 16 round spermatids could be seen. Analysis of the acid soluble proteins from nuclei on different types of Polyacrylamide gel electrophoretic systems has revealed that the levels of the testis specific histone variants Hlt, TH2A and TH2B, synthesized predominantly in the pachytene spermatocytes were greatly reduced in the testes of retinoate maintained rats. Following supplementation of retinyl acetate for either 4 days or 8 days the levels of these histone variants further decreased which correlated with the decrease in the number of pachytene spermatocytes. However, by day 12 of supplementation onwards, their levels started increasing and reached near normal levels by day 24 of vitamin A-supplementation     

Transgenic animals with altered high-density lipoprotein composition and functions

Our understanding of HDL metabolism in vivo has greatly advanced from studies with transgenic animals. Interactions between HDL apolipoproteins, transfer proteins, lipolytic enzymes and receptors modulate HDL size, particle number and fractional catabolic rate. The protective effect of HDL on atherosclerosis depends on the combined actions of HDL proteins and the metabolism of apo B-lipoproteins.