Because of the effect of photoperiod on physiological and biochemical processes in fish, this study aimed to evaluate the effect of manipulated photoperiod on growth, feed conversion and survival of wild carp, Cyprinus carpio. Fish received six photoperiod regimes (light:dark cycle) including: natural photoperiod (control), 24L:0D, 16L:8D, 12L:12D, 8L:16D and 0L:24D by the three replications. Regulated photoperiods as a 16L:8D or 12L:12D light/dark cycle significantly improved growth rate and food conversion ratio of wild carp.
Enigmatic morphological features of the formation and fate of “dark” (hyper-basophilic, hyper-argyrophilic and hyper-electrondense) neurons suggest that the mechanical work causing their dramatic shrinkage (whole-cell ultrastructural compaction) is done by a previously “unknown” ultrastructural component residing in the spaces between their “known” (i.e. visible in the conventional transmission electron microscopy) ultrastructural constituents. Embedment-free section electron microscopy revealed in these spaces the existence of a continuous network of gel microdomains, which is embedded in a continuous network of fluid-filled lacunae. We gathered experimental facts suggesting that this gel network is capable of a volume-reducing phase-transition (an established physico-chemical phenomenon), which could be the motor of the whole-cell ultrastructural compaction. The present paper revisits our relevant observations and speculates how such a continuous whole-cell gel network can do both whole-cell and compartmentalized mechanical work.
In aquatic macrophyte ecology, species abundance is usually estimated by cover values expressed on the ordinal scale. Recently, there has been increasing demand for three-dimensional estimates of plant abundance. To extend ordinal cover data into three dimensions, a new formula is proposed which considers the vertical developmental types of plants. In this, a constant k is used with three different values reflecting three groups of macrophytes, namely the “free floating leaved”; “rooted, floating leaved” and “submersed leaved” species. By using the new formula, inappropriate conversion and evaluation of ordinal abundance data occurring frequently in the literature may also be avoided.
Authors:N. Bukhari, Iram Siddique, K. Perveen, I. Siddiqui, and M. Alwahibi
Synthetic seed technology is an alternative to traditional micropropagation for production and delivery of cloned plantlets. Synthetic seeds were produced by encapsulating nodal segments of C. angustifolia in calcium alginate gel. 3% (w/v) sodium alginate and 100 mM CaCl2 · 2H2O were found most suitable for encapsulation of nodal segments. Synthetic seeds cultured on half strength Murashige and Skoog medium supplemented with thidiazuron (5.0 μM) + indole-3-acetic acid (1.0 μM) produced maximum number of shoots (10.9 ± 0.78) after 8 weeks of culture exhibiting (78%) in vitro conversion response. Encapsulated nodal segments demonstrated successful regeneration after different period (1–6 weeks) of cold storage at 4 °C. The synthetic seeds stored at 4 °C for a period of 4 weeks resulted in maximum conversion frequency (93%) after 8 weeks when placed back to regeneration medium. The isolated shoots when cultured on half strength Murashige and Skoog medium supplemented with 1.0 μM indole-3-butyric acid (IBA), produced healthy roots and plantlets with well-developed shoot and roots were successfully hardened off in plastic pots containing sterile soilrite inside the growth chamber and gradually transferred to greenhouse where they grew well with 85% survival rate. Growth performance of 2 months old in vitro-raised plant was compared with in vivo seedlings of the same age. Changes in the content of photosynthetic pigments, net photosynthetic rate (PN), superoxide dismutase and catalase activity in C. angustifolia indicated the adaptation of micropropagated plants to ex vitro conditions.
Authors:Joanna Smól, M. Astriab, Beata DUDZIŃSKA-MADEJ, and T. Twardowski
Gene expression is regulated at the critical steps: a regulatory event occurs at the step which has a criti- cal effect and is responsible for the limiting rate. Enzyme activity can be regulated at several different levels: transcriptional, translational or post-translational. In this review we describe (and illustrate with experimental data) plant stress which induces regulatory mechanisms at the translational and post-trans- lational levels. We found evidence for autorepression regulatory system of ferritin biosynthesis. Based on the knowl- edge of the molecular mechanism of regulation, we believe that ferritin protects the environment against heavy metal ions and supplements biological system(s) with iron. The quinolizidine alkaloids™ (QA) biosynthesis is lysine decarboxylase (LDC)-dependent. The avail- able pool of LDC limits the conversion of lysine to cadaverine. The amount of LDC depends on tran- scriptional and translational efficiency. However, in the light of the presented data, we have evidence for a post-translational regulatory system, i.e. the activation of LDC from low to high activity enzyme through the conversion from higher to lower molecular weight form. The plant protection system is very efficient. Understanding of the defence systems such as plant response to stress, should provide us with a possibility of applying this knowledge in practice and find- ing novel applications.
Authors:E. Skrzypek, M. Warchoł, I. Czyczyło-Mysza, I. Marcińska, A. Nowakowska, K. Dziurka, K. Juzoń, and A. Noga
Oat haploid embryos were obtained by wide crossing with maize. The effect of light intensity during the growing period of donor plants (450 and 800 µmol m−2 s−1) and in vitro cultures (20, 40, 70 and 110 µmol m−2 s−1) was examined for the induction and development of oat DH lines. Oat florets (26008) from 32 genotypes were pollinated with maize and treated with 2,4-dichlorophenoxyacetic acid. All the tested genotypes formed more haploid embryos when donor plants were grown in a greenhouse (9.4%) compared to a growth chamber (6.1%). The light intensity of 110 µmol m−2 s−1 during in vitro culture resulted in the highest percentage of embryo germination (38.9%), conversion into plants (36.4%) and DH line production (9.2%) when compared with lower light intensities (20, 40 and 70 µmol m−2 s−1). The results show that the growth conditions of the donor plant and light intensity during in vitro culture can affect the development of haploid embryos. This fact may have an impact on oat breeding programs using oat × maize crosses.
Authors:R. Singh, L. Ram, R.K. Singh, and D. Singh Jakhar
Maize protein quality is deficit in essential amino acids, lysine and tryptophan. These constraints of o2 (opaque2) are corrected in genetically improved, hard endosperm QPM (Quality Protein Maize). An integrated strategy of phenotypic selection for endosperm modifiers and molecular marker-assisted foreground and background selection has been used in present study. The QPM donors were, CML 161, DMRQPM 58, CML 176 and CML 141 whereas, normal maize inbreds were CM 212, V338, V361, V336, V341, V351, CM 141 and V335. The inbreds were subjected to parental polymorphism survey between non-QPM and QPM using CIMMYT based three SSR markers, viz. phi057, umc1066 and phi112. Two markers, viz. phi057 and umc1066 exhibited co-dominant reactions, while phi112 was dominant in nature. Finally, two combinations V335 × CML 141 and V351 × CML 141 were considered for conversion program. Foreground selection was exercised using o2 specific marker umc1066 in BC1 and BC2 generations, while background as well as foreground selection was exercised in BC2F3 generation to recover the genome of recurrent parent up to extent of 80 to 100% with the help of SSR markers distributed across the whole maize genome. The tryptophan concentration in endosperm protein was significantly enhanced and the converted maize lines had almost twice the amount of lysine and tryptophan than normal maize inbreds.
Authors:C. Battisti, L. Luiselli, B. Frank, and E. Lorenzetti
Breeding bird assemblages and species present in two ‘archipelagos” of wood fragments, included in fragmented landscape of Central Italy, were studied in springs 2002 and 2003 with line transect method (1: Cornicolan hills study area: 20 fragments; 2: Anzio-Nettuno study area: 13 fragments). An area effect was shown in diversity/dominance analyses carried out by species rank/frequency diagrams obtained for the wood fragment assemblages of two ‘archipelagos’. Smaller fragments showed a lower species richness, a higher relative frequencies of first dominant species and a higher value of angular coefficient of assemblage lines. When fragment area decreases, the assemblage tendency lines in diversity/dominance diagrams show a higher slope (i.e., higher angular coefficient). Simpson dominance index was inversely correlated to fragment area: smaller fragments concentrate dominance in less species compared to larger ones. This approach suggests that the reduction in area of wood fragments could be comparable to a stress on breeding bird assemblages induced by anthropogenic habitat conversion and fragmentation, here considered as a disturbance at landscape level.
Authors:Munisch Wadwa, Robert Klopfleisch, Jan Buer, and Astrid M. Westendorf
The endocytotic c-type lectin receptor DEC-205 is highly expressed on immature dendritic cells. In previous studies, it was shown that antigen-targeting to DEC-205 is a useful tool for the induction of antigen-specific Foxp3+ regulatory T cells and thereby can prevent inflammatory processes. However, whether this approach is sufficient to mediate tolerance in mucosal tissues like the gut is unknown. In this study, we established a new mouse model in which the adoptive transfer of naive hemagglutinin (HA)-specific CD4+Foxp3− T cells into VILLIN-HA transgenic mice leads to severe colitis. To analyze if antigen-targeting to DEC-205 could protect against inflammation of the gut, VILLIN-HA transgenic mice were injected with an antibody–antigen complex consisting of the immunogenic HA110–120 peptide coupled to an α-DEC-205 antibody (DEC-HA) before adoptive T cell transfer. DEC-HAtreated mice showed significantly less signs of intestinal inflammation as was demonstrated by reduced loss of body weight and histopathology in the gut. Strikingly, abrogated intestinal inflammation was mediated via the conversion of naive HA-specific CD4+Foxp3− T cells into HA-specific CD4+Foxp3+ regulatory T cells. In this study, we provide evidence that antigen-targeting to DEC-205 can be utilized for the induction of tolerance in mucosal organs that are confronted with large numbers of exogenous antigens.