An unexpected noncarpellate epigynous flower from the Jurassic of China.

The origin of angiosperms has been a long-standing botanical debate. The great diversity of angiosperms in the Early Cretaceous makes the Jurassic a promising period in which to anticipate the origins of the angiosperms. Here, based on observations of 264 specimens of 198 individual flowers preserved on 34 slabs in various states and orientations, from the South Xiangshan Formation (Early Jurassic) of China, we describe a fossil flower, gen.

Subcellular distribution and toxicity of cadmium in Potamogeton crispus L.

The submerged macrophyte Potamogeton crispus L. was subjected to varying doses of cadmium (0, 20, 40, 60 and 80 μM) for 7 d, and the plants were analyzed for subcellular distribution of Cd, accumulation of mineral nutrients, photosynthesis, oxidative stress, protein content, and ultrastructural distribution of calcium (Ca). Leaf fractionation by differential centrifugation indicated that 48-69% of Cd was accumulated in the cell wall.

Palaeontological evidence of membrane relationship in step-by-step membrane fusion.

Studies on membrane fusion in living cells indicate that initiation of membrane fusion is a transient and hard to capture process. Despite previous research, membrane behaviour at this point is still poorly understood. Recent palaeobotanical research has revealed snapshots of membrane fusion in a 15-million-year-old fossil pinaceous cone.

Atomic force microscope observation on ultrastructures in plant cells.

AFM is being applied in increasingly wide research fields and extracting more biochemical/biophysical information that is beyond the capability of traditional SEM and TEM. Due to its inherent features, AFM is rarely used to observe the subcellular details within cells. Although subcellular features were recently observed on thin sections of plant tissues using AFM, this method might introduce unexpected artifacts during sample processing.

[Effects of Ni2+ on physiological characteristics and submicroscopic structure of Salvinia natans leaves].

Influence of 0, 5, 10, 15, 20 mg/L Ni2+ on growth, mineral nutrition, chlorophyll, carotenoid, soluble protein, soluble sugar, superoxide (O2*-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents as well as the activities of superoxide dismutase (SOD), guaiacolperoxidase (POD), and catalase (CAT) were studied in the leaves of Salvinia natans plants on 10 days after treatment. With the increase of the Ni2+ concentrations, exposure of the plants revealed that, (1) the addition of Ni2+ affected the absorption of mineral nutrients, it mainly increased the absorption of Ca2+, Na+, Zn2+, Fe3+ and Mg2+, while reduced that of Mn2+, Mo2+, P and K+. (2) The content of chlorophyll, carotenoid, soluble protein and soluble sugar content as well as activities of SOD and CAT decreased gradually.

[Toxic effects of Hg2+, Cd2+ and Cu2+ on cell membrane system of Cabomba caroliniana A. Gray].

By the observation with electron- and confocal laser scanning microscopy and the determination of physiological and biochemical reactions, the toxic effects of Hg2+, Cd2+ and Cu2+ on the cell membrane system of Cabomba caroliniana A. Gray were investigated. The results showed that under the actions of the three heavy metal ions, the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) in C.

Paleontological evidence for membrane fusion between a unit membrane and a half-unit membrane.

Membrane fusion is of fundamental importance for many biological processes and has been a topic of intensive research in past decades with several models being proposed for it. Fossils had previously not been considered relevant to studies on membrane fusion. But here two different membrane fusion patterns are reported in the same well-preserved fossil plant from the Miocene (15-20 million years old) at Clarkia, Idaho, US.

[Changes in selectin in early stage of lung injury induced by endotoxic shock in macaque].

Objective: To investigate the change in selectin and its effect on lung injury induced by endotoxic [lipopolysaccharide (LPS)] shock in macaque.

Methods: Eleven macaques were randomly divided into two groups: control group (n=5) and LPS group (n=6). The animals of the control group received injection of 1 ml/kg normal saline, and the animals of the LPS group received a dose of 2.

Morphology of spiroplasmas in the Chinese mitten crab Eriocheir sinensis associated with tremor disease.

The structure of spiroplasmas in the Chinese mitten crab associated with tremor disease was studied by transmission electron microscopy techniques, including both negative staining and ultrasectioning. A spiral structure, which is a typical form of spiroplasmas, could be detected and the observations showed for the first time the presence of spiroplasmas in the cells of the crab. Propagation of spiroplasmas within the cells presented various forms that could be sorted into three morphological types: rounded, regular helical, and pleiomorphic or intermediate forms.

[Toxic effects of Cd2+ pollution on the biochemical and physiological characters and ultrastructure of Alternanthera philoxeroides].

By imitating different concentration Cd2+ polluted water environment, this paper dealt with the changes of some biochemical and physiological characters and the damage of ultrastructure in leaves of Alternanthera philoxeroides. The result showed that SOD and POD activity first increased in the low concentration pollution and then decreased with the concentration of pollution raised. The content of chlorophyll, chlorophyll a/b value, CAT activity and the content of soluble protein all declined continually.

Study on experimental infections of Spiroplasma from the Chinese mitten crab in crayfish, mice and embryonated chickens.

Tremor disease (TD) of the Chinese mitten crab Eriocheir sinensi has become a serious disease in the Chinese freshwater culture industry in recent years. The agent, belonging to Spiroplasma, was purified from yolk and allantoic fluids of chicken embryos and was then inoculated into the body of crayfish, the abdominal cavity of ICR mice and the allantoid of chicken embryos, respectively. Thirty-eight days after the inoculation, the mice and crayfish were dissected and their tissues sampled and observed with both the light and electron microscope.