Volume changes accompanying the complex formation of polyadenylic and polyuridylic acids

The complex formation of polyadenylic acid (poly A) and polyuridylic acid (poly U) in 0.1M NaCl solution containing 0.01M sodium cacodylate was followed by dilatometric measurements at various mixing ratios of poly A and poly U. The volume changes, ΔV, accompanying the formation of poly A. poly U and poly A.2poly U were + l.5 and + 2.5 ml per mole of the nucleotide residue, respectively. This increase in volume was probably due to the increased counterion binding when the single-stranded polynucleotides were converted into the double- and triple-stranded helices, since depletion of charged species from the solvent proper would lessen the effect of electrostriction, thus resulting in a positive ΔV. The conversion of a single-stranded poly A to a double-stranded helix in acidic solution led to a ΔV of + 3.8 ml per mole of the nucleotide residue. This increase in volume was attributed to the charge neutralization as a result of protonation of the adenine bases.     

Development of an efficient,genotype independent plant regeneration and transformation protocol using cotyledonary nodes in safflower (<Emphasis Type="Italic">Carthamus tinctorius</Emphasis> L.)

Safflower is an important oilseed crop with a nutritionally desirable oil composition comprising low levels of saturated fatty acids and high levels of unsaturated fatty acids. In this study, a robust, genotype-independent plant regeneration protocol was developed for geographically diverse safflower genotypes, including one accession each from America, Australia, Egypt, Germany, Kazakhstan and three important Indian genotypes (Sharda, Bhima and PBNS-12). Use of cotyledonary nodes as explants resulted in genotype-independent regeneration on BAP (6-Benzylaminopurine), NAA (Naphthalene acetic acid) and ascorbic acid supplemented MS medium. Histological analysis revealed that multiple shoot apical meristems originated independently from peripheral cortical regions of explants. We developed a highly efficient in vitro micrografting method which enabled successful rooting of 85–90 % of regenerated shoots. An efficient genetic transformation system was also established for three Indian genotypes viz., Sharda, Bhima and PBNS-12 using the Agrobacterium strain, LBA4404 and phosphinothricin as the selection agent. This is the first report on use of phosphinothricin-based selection and cotyledonary nodes as explants for Agrobacterium-mediated transformation of safflower. Use of vacuum infiltration-assisted Agrobacterium infection and inclusion of a pre-culture step significantly increased transformation frequencies in all the three genotypes as seen by GUS assays on transformed calli. Genomic integration and transgene expression were confirmed by PCR, Southern hybridization and GUS assays. Most transgenic plants (90 %) exhibited a normal phenotype when grown under controlled conditions and produced viable seeds. This protocol would be useful for introduction of desirable traits in diverse genotypes of safflower.     

Genetic and Genomic Resources of Small Millets

Small millets are very promising agricultural entity to ensure global food security. They gained remarkable importance in agriculture due to their resilience to climatic changes and increasing demand for nutritious food and feed. The genetic variability in the core and mini-core germplasm of small millets was characterized for nutritional composition and capacity to tolerate abiotic stresses that can be infused in breeding programs. Other than the foxtail millet, availability of genomic information in small millets is far below the mark for use in marker-assisted breeding and other genetic improvement programs. The genome sequence of foxtail millet has recently triggered a plethora of post-genomic analysis and envisaged foxtail millet as a model organism for the C₄ grasses and bioenergy research. Recent developments in the next-generation sequencing technologies enabled us, with the simultaneous discovery of high-throughput markers and multiplexed genotyping of germplasm, to speedup marker-assisted breeding. In this context, an in-depth analysis of the wealth of diverse germplasm resources and future perspectives of integrating genomics in genome-wide marker-trait association and breeding in small millets is worthy.     

Growth and physiochemical responses of <Emphasis Type="Italic">Camelina sativa</Emphasis> L. under UV-C stress

A study was conducted to estimate the effect of UV-C (200–280 nm) radiation stress on growth and physiochemical responses of Camelina sativa L. cv. Calina (EC643910; a potential bio-fuel crop) for its possible mass multiplication at high-altitude under high radiations. The germination percentage in terms of radicle protrusion and opening of cotyledonary leaves significantly decreased 13.98 and 27.8 %, respectively, as compared to control. However, no significant change was observed in growth parameters including root and shoot lengths and fresh biomass. The relative membrane leakage rate and lipid peroxidation as a malondialdehyde contents significantly increased with the value of ~99 % and 0.17 mM g^?1 FW, respectively, under UV-C stress. Also, the proline, glycine betaine and total soluble sugars contents increased by ~330, ~440, ~144 %, respectively, as compared to control. Among non-enzymatic antioxidants, the ascorbic acid and total phenol contents significantly increased by ~284 and ~537 %, respectively, as compared to control. Likewise, the activity of antioxidant enzyme, ascorbate peroxidase, guaiacol peroxidase and catalase increased under UV-C stress with the value of 1.03, 0.05 and 0.06 µmol mg protein^?1 min^?1, respectively. In addition, the chlorophyll a, b and total (a + b) contents decreased by ~180, ~151 and ~147 %, respectively, as compared to control. In contrast, the total carotenoids and anthocyanin contents increased by ~160 and ~184 %, respectively. Our findings suggest the adaptive growth and physiochemical responses of C. sativa under UV-C stress. Therefore, it may be recommended for large-scale cultivation at high-altitude under intense natural radiations for future bio-fuel production.     

Assessment of photosynthetic potential of indoor plants under cold stress

Photosynthetic parameters including net photosynthetic rate (P_N), transpiration rate (E), water-use efficiency (WUE), and stomatal conductance (g_s) were studied in indoor C₃ plants Philodendron domesticum (Pd), Dracaena fragans (Df), Peperomia obtussifolia (Po), Chlorophytum comosum (Cc), and in a CAM plant, Sansevieria trifasciata (St), exposed to various low temperatures (0, 5, 10, 15, 20, and 25°C). All studied plants survived up to 0°C, but only St and Cc endured, while other plants wilted, when the temperature increased back to room temperature (25°C). The P_N declined rapidly with the decrease of temperature in all studied plants. St showed the maximum P_N of 11.9 μmol m^?2 s^?1 at 25°C followed by Cc, Po, Pd, and Df. E also followed a trend almost similar to that of P_N. St showed minimum E (0.1 mmol m^?2 s^?1) as compared to other studied C₃ plants at 25°C. The E decreased up to ≈4-fold at 5 and 0°C. Furthermore, a considerable decline in WUE was observed under cold stress in all C₃ plants, while St showed maximum WUE. Similarly, the g_s also declined gradually with the decrease in the temperature in all plants. Among C₃ plants, Pd and Po showed the maximum g_s of 0.07 mol m^?2 s^?1 at 25°C followed by Df and Cc. However, St showed the minimum g_s that further decreased up to ～4-fold at 0°C. In addition, the content of photosynthetic pigments [chlorophyll a, b, (a+b), and carotenoids] was varying in all studied plants at 0°C. Our findings clearly indicated the best photosynthetic potential of St compared to other studied plants. This species might be recommended for improving air quality in high-altitude closed environments.     

Mucosal T lymphocyte numbers are selectively reduced in integrin alpha E (CD103)-deficient mice.

The mucosal lymphocyte integrin alpha E(CD103)beta 7 is thought to be important for intraepithelial lymphocyte (IEL) localization or function. We cloned the murine integrin gene encoding alpha E, localized it to chromosome 11, and generated integrin alpha E-deficient mice. In alpha E-/- mice, intestinal and vaginal IEL numbers were reduced, consistent with the known binding of alpha E beta 7 to E-cadherin expressed on epithelial cells. However, it was surprising that lamina propria T lymphocyte numbers were diminished, as E-cadherin is not expressed in the lamina propria. In contrast, peribronchial, intrapulmonary, Peyer's patch, and splenic T lymphocyte numbers were not reduced in alpha E-deficient mice. Thus, alpha E beta 7 was important for generating or maintaining the gut and vaginal T lymphocytes located diffusely within the epithelium or lamina propria but not for generating the gut-associated organized lymphoid tissues. Finally, the impact of alpha E deficiency upon intestinal IEL numbers was greater at 3-4 wk of life than in younger animals, and affected the TCR alpha beta+ CD8+ T cells more than the gamma delta T cells or the TCR alpha beta+ CD4+CD8- population. These findings suggest that alpha E beta 7 is involved in the expansion/recruitment of TCR alpha beta+ CD8+ IEL following microbial colonization. Integrin alpha E-deficient mice will provide an important tool for studying the role of alpha E beta 7 and of alpha E beta 7-expressing mucosal T lymphocytes in vivo.     

Tracing the development of learned song preferences in the female zebra finch brain with functional magnetic resonance imaging

In sexually dimorphic zebra finches (Taeniopygia guttata), only males learn to sing their father's song, whereas females learn to recognize the songs of their father or mate but cannot sing themselves. Memory of learned songs is behaviorally expressed in females by preferring familiar songs over unfamiliar ones. Auditory association regions such as the caudomedial mesopallium (CMM; or caudal mesopallium) have been shown to be key nodes in a network that supports preferences for learned songs in adult females. However, much less is known about how song preferences develop during the sensitive period of learning in juvenile female zebra finches. In this study, we used blood-oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to trace the development of a memory-based preference for the father's song in female zebra finches. Using BOLD fMRI, we found that only in adult female zebra finches with a preference for learned song over novel conspecific song, neural selectivity for the father's song was localized in the thalamus (dorsolateral nucleus of the medial thalamus; part of the anterior forebrain pathway, AFP) and in CMM. These brain regions also showed a selective response in juvenile female zebra finches, although activation was less prominent. These data reveal that neural responses in CMM, and perhaps also in the AFP, are shaped during development to support behavioral preferences for learned songs.     

使用多态异型酶标记物估计野鲮的遗传变异性

本文首次分析了野鲮鱼 (Labeodyocheilus)等位酶的变异情况。通过对 17个酶系统的研究 ,发现 2 8个可以稳定检测的位点 ,其中 8个位点具有多态性。使用这 8个等位酶位点 ,分析了取自不同河流 ,即Satluj、Yamuna和Tons河的样本的遗传多样性情况。结果显示 ,不同样本间存在显著的遗传异质性 ,各位点的表观杂合度介于 0 0 392 (Yamuna河 )与 0 0 4 87(Tons河 )之间。因此 ,本研究所筛选出的多态性等位酶位点为研究该野鲮鱼的种群遗传结构奠定了基础