Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves

The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –¹⁴CO₂ fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes.     

Toll-like receptor deficiency worsens inflammation and lymphedema after lymphatic injury

Mechanisms regulating lymphedema pathogenesis remain unknown. Recently, we have shown that lymphatic fluid stasis increases endogenous danger signal expression, and these molecules influence lymphatic repair (Zampbell JC, et al. Am J Physiol Cell Physiol 300: C1107-C1121, 2011). Endogenous danger signals activate Toll-like receptors (TLR) 2, 4, and 9 and induce homeostatic or harmful responses, depending on physiological context. The purpose of this study was to determine the role of TLRs in regulating tissue responses to lymphatic fluid stasis. A surgical model of lymphedema was used in which wild-type or TLR2, 4, or 9 knockout (KO) mice underwent tail lymphatic excision. Six weeks postoperatively, TLR KOs demonstrated markedly increased tail edema compared with wild-type animals (50-200% increase; P < 0.01), and this effect was most pronounced in TLR4 KOs (P < 0.01). TLR deficiency resulted in decreased interstitial and lymphatic transport, abnormal lymphatic architecture, and fewer capillary lymphatics (40-50% decrease; P < 0.001). Lymphedematous tissues of TLR KOs demonstrated increased leukocyte infiltration (P < 0.001 for TLR4 KOs), including higher numbers of infiltrating CD3+ cells (P < 0.05, TLR4 and TLR9 KO), yet decreased infiltrating F4/80+ macrophages (P < 0.05, all groups). Furthermore, analysis of isolated macrophages revealed twofold reductions in VEGF-C (P < 0.01) and LYVE-1 (P < 0.05) mRNA from TLR2-deficient animals. Finally, TLR deficiency was associated with increased collagen type I deposition and increased transforming growth factor-β1 expression (P < 0.01, TLR4 and TLR9 KO), contributing to dermal fibrosis. In conclusion, TLR deficiency worsens tissue responses to lymphatic fluid stasis and is associated with decreased lymphangiogenesis, increased fibrosis, and reduced macrophage infiltration. These findings suggest a role for innate immune responses, including TLR signaling, in lymphatic repair and lymphedema pathogenesis.     

Fractional modeling dynamics of HIV and CD4<Superscript>+</Superscript> T-cells during primary infection

In this paper, we introduce fractional-order into a model of HIV-1 infection of CD4⁺ T cells. We study the effect of the changing the average number of viral particles N with different sets of initial conditions on the dynamics of the presented model. Generalized Euler method (GEM) will be used to find a numerical solution of the HIV-1 infection fractional order model.     

Evolution of sexual size dimorphism in grouse and allies (Aves: Phasianidae) in relation to mating competition,fecundity demands and resource division

Sexual size dimorphism (SSD) is often assumed to be driven by three major selective processes: (1) sexual selection influencing male size and thus mating success, (2) fecundity selection acting on females and (3) inter‐sexual resource division favouring different size in males and females to reduce competition for resources. Sexual selection should be particularly strong in species that exhibit lek polygyny, since male mating success is highly skewed in such species. We investigated whether these three selective processes are related to SSD evolution in grouse and allies (Phasianidae). Male‐biased SSD increased with body size (Rensch’s rule) and lekking species exhibited more male‐biased SSD than nonlekking ones. Directional phylogenetic analyses indicated that lekking evolved before SSD, but conclusions were highly dependent on the body size traits and chosen model values. There was no relationship between SSD and male display agility, nor did resource division influence SSD. Although clutch mass increased with female body size it was not related to the degree of SSD. Taken together, the results are most consistent with the hypothesis that lekking behaviour led to the evolution of male‐biased SSD in Phasianidae.     

Recent divergence,intercontinental dispersal and shared polymorphism are shaping the genetic structure of amphi‐Atlantic peatmoss populations

Several lines of evidence suggest that recent long‐distance dispersal may have been important in the evolution of intercontinental distribution ranges of bryophytes. However, the absolute rate of intercontinental migration and its relative role in the development of certain distribution ranges is still poorly understood. To this end, the genetic structure of intercontinental populations of six peatmoss species showing an amphi‐Atlantic distribution was investigated using microsatellite markers. Methods relying on the coalescent were applied (im and migrate ) to understand the evolution of this distribution pattern in peatmosses. Intercontinental populations of the six peatmoss species were weakly albeit significantly differentiated (average F_ST = 0.104). This suggests that the North Atlantic Ocean is acting as a barrier to gene flow even in bryophytes adapted to long‐range dispersal. The im analysis suggested a relatively recent split of intercontinental populations dating back to the last two glacial periods (9000–289 000 years ago). In contrast to previous hypotheses, analyses indicated that both ongoing migration and ancestral polymorphism are important in explaining the intercontinental genetic similarity of peatmoss populations, but their relative contribution varies with species. Migration rates were significantly asymmetric towards America suggesting differential extinction of genotypes on the two continents or invasion of the American continent by European lineages. These results indicate that low genetic divergence of amphi‐Atlantic populations is a general pattern across numerous flowering plants and bryophytes. However, in bryophytes, ongoing intercontinental gene flow and retained shared ancestral polymorphism must both be considered to explain the genetic similarity of intercontinental populations.