Selective phagocytosis of gram-positive bacteria and interleukin 1-like factor production by a subpopulation of large granular lymphocytes

There has been a consensus that a large granular lymphocyte (LGL) population with natural killer (NK) function is nonadherent and nonphagocytic. However, a significant proportion of the nonadherent cells purified by the two-step depletion of adherent cells with a plastic surface and nylon wool columns engulfed Sta. aureus into their cytoplasm. These cells were morphologically identified as LGL in light and electron microscopies. Two-color immunofluorescence tests, furthermore, demonstrated that Leu-11+ LGL, Leu-11+7-, and Leu-11+7+, but not Leu-11-7+, phagocytosed Sta. aureus. Among the particles tested here, only Gram(+) bacteria were preferentially phagocytosed, whereas Gram(-) bacteria, other large-sized microbes (e.g., baker's yeast and Candida albicans), latex, silica, and carbonyl iron were not. LGL exhibited a substantial level of bactericidal activity against Sta. aureus, although the level was one third of that mediated by monocytes. When Gram(+) bacteria were incubated with nonadherent cells for 18 hr, significant amounts of interleukin 1 (IL 1)-like factors (or IL 1 itself) as well as interferon were detected in the supernatants. On the other hand, this incubation did not induce interleukin 2 (IL 2). The IL 1-like factor producer cells were demonstrated to be the low-density lymphocytes on Percoll separation and to have the Leu-11+ phenotype. The phagocytosis was suggested to be an important stimulus in producing IL 1-like factors from LGL. Thus, the treatment of cells with cytochalasin B, a microfilament disrupting agent, completely abrogated both phagocytosis and IL 1-like factor production. Some cell wall components of Gram(+) bacteria might be important to a recognition process of the phagocytosis, since the protoplasts of Sta. aureus, when prepared by the treatment of bacteria with lysostaphin, were no longer phagocytosed by LGL. The present results therefore identify an additional unique characteristic similar to, but not identical with, the myelomonocytic nature of Leu-11+ LGL.     

Na+ dependence of phenacetin absorption

Phenacetin in solution at different concentrations of Na+ was orally administered to dogs. Phenacetin absorption is increased by the Na+: a positive correlation was noted between the Na+ concentration in the medium and the plasma levels of phenacetin. Ouabain antagonizes the effect of Na+ on phenacetin absorption.     

Impaired carotenogenesis can affect organization and functionality of etioplast membranes

The effects of impaired carotenogenesis on plastid membrane organization, functionality and stability were studied in etiolated barley plants grown at 20 and 30°C. The plants were treated with norflurazon or amitrole, two herbicides affecting phytoene desaturation and lycopene cyclization, respectively. At 20°C, the amitrole-treated etioplasts, which accumulated lycopene in their inner membranes, exhibited disorganized prolamellar bodies, containing a prevalent form of non-phototransformable protochlorophyllide (Pchlide). They also showed a certain difficulty in reducing the phototransformable pigment to chlorophyllide when exposed to light, and were unable to reform the active ternary complex [protochlorophyllide–oxidoreductase (POR)–Pchlide–NADPH] when placed back in darkness. No ultrastructural alterations were found in norflurazon-treated etioplasts, with carotenogenesis inhibited at the phytoene desaturation step. In these latter organelles, Pchlide, whose forms were comparable with those of the control etioplasts, was photoreduced quickly after illumination and the ternary complex was reformed during a subsequent dark period. Thus, the impaired carotenogenesis leading to the accumulation of lycopene showed greater interference with the etioplast membrane arrangement and functionality than did the earlier interruption of the biosynthetic pathway at the phytoene level. This might be due to the different interactions of the distinct carotenoid precursors with other membrane components. However, in etioplasts of norflurazon-treated plants, a rise in growth temperature caused a partial demolition of prolamellar bodies, showing a lowered thermostability of the carotenoid-deficient membranes. This latter effect strengthens the concept that a correct and complete carotenogenesis pathway, leading to the synthesis of polar carotenoids (i.e. xanthophylls), is required for the maintenance of stable plastid membranes.     

Further surveys of Pseliodinium vaubanii Sournia (Pirrophyta) in the Adriatic sea

Abstract

The presence, in the North Adriatic sea and in the Chioggia and Marano lagoons, of Pseliodinium vaubanii a rare dinoflagellate species, is reported. Our results showed that Pseliodinium vaubanii is a very frequent and abundant species in these environments.     

RS‐1 enhances CRISPR‐mediated targeted knock‐in in bovine embryos

Targeted knock‐in (KI) can be achieved in embryos by clustered regularly interspaced short palindromic repeats (CRISPR)‐assisted homology directed repair (HDR). However, HDR efficiency is constrained by the competition of nonhomologous end joining. The objective of this study was to explore whether CRISPR‐assisted targeted KI rates can be improved in bovine embryos by exposure to the HDR enhancer RS‐1. In vitro produced zygotes were injected with CRISPR components (300 ng/µl Cas9 messenger RNA and 100 ng/µl single guide RNA against a noncoding region) and a single‐stranded DNA (ssDNA) repair template (100 ng/µl). ssDNA template contained a 6 bp XbaI site insert, allowing targeted KI detection by restriction analysis, flanked by 50 bp homology arms. Following microinjection, zygotes were exposed to 0, 3.75, or 7.5 µM RS‐1 for 24 hr. No differences were noted between groups in terms of development or genome edition rates. However, targeted KI rates were doubled in the group exposed to 7.5 µM RS‐1 compared to the others (52.8% vs. 25% and 23.1%, for 7.5, 0, and 3.75 µM, respectively). In conclusion, transient exposure to 7.5 µM RS‐1 enhances targeted KI rates resulting in approximately half of the embryos containing the intended mutation, hence allowing direct KI generation in embryos.     

Enhancement of salt tolerance in corn using Azospirillum brasilense: an approach on antioxidant systems

Journal of Plant Research - Salinity has become one of the major factors limiting agricultural production. In this regard, different cost-effective management strategies such as the use of plant...     

Developing of a model to predict lying behavior of dairy cows on silvopastoral system during the winter season

International Journal of Biometeorology - Lying behavior is an important indicator of the cows’ welfare and health. In this study, we evaluate the effect of the physical environment on dairy...     

Phytoplankton and chemico-physical parameters of the Scardovari Lagoon (Po Delta,North Adriatic Sea) during 1991 and 1992

Abstract

During research directed towards the employment of the biological resources of the North Adriatic lagoons, from January 1991 to December 1992, in both tidal phases, a survey was carried out on the phytoplankton and the chemico-physical parameters of the Scardovari lagoon. Data analyses allowed two different areas to be distinguished: one inner, which was generally characterized by high phytoplanktonic densities (St. 3–4), the other outer, which was more influced by marine load (St. 1–2). Photosynthetic picoplankton was dominant in terms of cell number in most samples. Phytoplanktonic fraction >2 μm was represented mainly by diatoms, which showed the higher species number. During the sample observation, some dinoflagellates, considered toxic or potentially toxic, were found. Their presence was important because of their effect on the bivalve mollusc cultures.