Calcium and calcium receptor CAS promote Arabidopsis thaliana de-etiolation.

As a second messenger, the free cytosolic calcium ion (Ca(2+)) plays important roles in many biochemical and physiological processes including photosynthesis in plants. In this study, we investigated morphological changes, chlorophyll accumulation and chloroplast development during early photomorphogenesis in etiolated seedlings of both Arabidopsis thaliana wild type (WT) and those with the antisense of CAS, a calcium sensor (CASas). Seedlings were grown at high, medium and low Ca(2+) concentrations to identify the roles of Ca(2+) and CAS in de-etiolation and chloroplast development. The results demonstrated that Ca(2+) and CAS are correlated with de-etiolation of A. thaliana after light exposure. High Ca(2+) significantly increased chlorophyll content and improved chloroplast development in both A. thaliana WT and CASas etiolated seedlings during de-etiolation. The analysis by western blot and real-time fluorescent quantitative polymerase chain reaction indicated that the expression levels of CAS mRNA and protein were upregulated by white light and external Ca(2+) significantly. Etiolated CASas plants showed much lower chlorophyll content and delay of chloroplast development as compared with WT plants, indicating that CAS functions in de-etiolation. All together, we concluded that the de-etiolation in A. thaliana was promoted by the high Ca(2+) concentration and CAS expression to a certain extent.

Effects of calcium on seed germination, seedling growth and photosynthesis of six forest tree species under simulated acid rain.

We selected six tree species, Pinus massoniana Lamb., Cryptomeria fortunei Hooibr. ex Otto et Dietr., Cunninghamia lanceolata (Lamb.) Hook., Liquidambar formosana Hance, Pinus armandii Franch. and Castanopsis chinensis Hance, which are widely distributed as dominant species in the forest of southern China where acid deposition is becoming more and more serious in recent years. We investigated the effects and potential interactions between simulated acid rain (SiAR) and three calcium (Ca) levels on seed germination, radicle length, seedling growth, chlorophyll content, photosynthesis and Ca content in leaves of these six species. We found that the six species showed different responses to SiAR and different Ca levels. Pinus armandii and C. chinensis were very tolerant to SiAR, whereas the others were more sensitive. The results of significant SiAR × Ca interactions on different physiological parameters of the six species demonstrate that additional Ca had a dramatic rescue effect on the seed germination and seedling growth for the sensitive species under SiAR. Altogether, we conclude that the negative effects of SiAR on seed germination, seedling growth and photosynthesis of the four sensitive species could be ameliorated by Ca addition. In contrast, the physiological processes of the two tolerant species were much less affected by both SiAR and Ca treatments. This conclusion implies that the degree of forest decline caused by long-term acid deposition may be attributed not only to the sensitivity of tree species to acid deposition, but also to the Ca level in the soil.

Evaluation of the ultrasensitive human immunodeficiency virus type 1 (HIV-1) p24 antigen assay performed on dried blood spots for diagnosis of HIV-1 infection in infants.

The diagnostic accuracy of the modified p24 antigen assay performed on pediatric dried blood spots was evaluated. Samples analyzed within 6 weeks of collection yielded no false-positive results (specificity, 100%) and few false-negative results (sensitivity, 96.5% to 98.3%). Laboratory services with limited resources should assess this option for routine infant diagnosis.

Low risk of contamination with automated and manual excision of dried blood spots for HIV DNA PCR testing in the routine laboratory.

In low resource settings the inability to diagnose HIV in infants early presents a major obstacle to providing care for HIV-infected children. Dried blood spot samples offer a solution to the scarcity of skills available for venesecting young infants but pose challenges to laboratories because their processing requirements are distinct from that of the liquid blood samples widely used for viral detection assays. Different methods of excising 287 paired HIV-positive and HIV-negative dried blood spot samples (n=574) for testing by the Roche Amplicor HIV-1 DNA assay version 1.5 were assessed. A manual punch in conjunction with three different cleaning protocols (n=372) and an automated punch (BSD 1000 GenePunch) using a single cleaning protocol (n=202) was assessed for the risk of cross contamination between samples. A single false positive result obtained using the automated punch may have been attributable to contamination during the excision step of the assay. Excision of dried blood spot samples is associated with a very low risk of cross contamination regardless of the instrument or cleaning intervention used. The process of excising dried blood spot samples should not compromise the results of HIV viral detection assays performed on dried blood spots in routine laboratories which is encouraging for increasing access to an accurate diagnosis of HIV in infants.

Evaluation of dried whole blood spots obtained by heel or finger stick as an alternative to venous blood for diagnosis of human immunodeficiency virus type 1 infection in vertically exposed infants in the routine diagnostic laboratory.

The diagnostic accuracy of the Roche Amplicor human immunodeficiency virus type 1 DNA PCR assay (version 1.5) on DNA extracted from pediatric heel prick dried blood spots using Roche MagNA Pure nucleic acid purification technology was evaluated. The methodologies transfer successfully from the labor-intensive research laboratory to the high-throughput automated routine laboratory.

Ultrasensitive human immunodeficiency virus type 1 p24 antigen assay modified for use on dried whole-blood spots as a reliable, affordable test for infant diagnosis.

The ultrasensitive human immunodeficiency virus (HIV) p24 antigen assay was modified for use on pediatric dried whole-blood spots on Whatman no. 1 filter paper. The modified assay was found to be reliable and accurate, making it an affordable tool for pediatric HIV diagnosis in developing countries.

Tissue engineering: TGF-beta superfamily members and delivery systems in bone regeneration.

The induction of bone formation requires three parameters that interact in a highly regulated process: soluble osteoinductive signals, capable responding cells, and a supporting matrix substratum or insoluble signal. The use of recombinant and naturally derived bone morphogenetic proteins and transforming growth factor beta(s) (TGF-beta(s)) has increased our understanding of the functions of these morphogens during the induction of endochondral bone formation. In addition, growing understanding of the cellular interactions of living tissues with synthetic biomaterials has led to the in vivo induction of bone formation using porous biomimetic matrices as an alternative to the use of autografts for bone regeneration. This review outlines the basis of bone tissue engineering by members of the TGF-beta superfamily, focusing on their delivery systems and the intrinsic induction of bone formation by specific biomimetic matrices with a defined geometry.