The lipid-binding SEC14 domain

Protein-lipid interactions are important for protein targeting, signal transduction, lipid transport, lipid biosynthesis, lipid metabolism, and the maintenance of cellular compartments and membranes. Specific lipid-binding protein domains, such as PH, FYVE, PX, PHD, C2 and SEC14 homology domains, mediate interactions between proteins and specific phospholipids. Here we review the published literature, plus some of our most recent unpublished findings, regarding the biology of the SEC14 domain, also known as CRAL_TRIO domain.     

Structural differences between <Emphasis Type="Italic">Fusarium</Emphasis> strains investigated by FT-IR spectroscopy

The structural characteristics of Fusarium have received attention from both pure and applied scientists. Because many genes and physiological mechanisms are involved in the development of a particular structure type, this research is complicated. For revealing the structure of macromolecule in these fungal cells, FT-IR spectroscopy combined with multivariate statistical analysis was performed to characterize the structure of protein and polysaccharide of spores and mycelia obtained from different culture medium. The second derivative FT-IR spectra exhibited strain-specific infrared characteristics in the protein secondary structure sensitive amide I region. The region between 750 and 950 cm⁻¹ assigned to α-and β-glucans was investigated for studied samples. Principal components analysis (PCA) allowed us to separate mycelia into two clusters according to different growth medium, indicating that spectra of strains may have been greatly affected by cultivation conditions. Published in Russian in Biokhimiya, 2007, Vol. 72, No. 1, pp. 72–79.     

Relationships Between Population Growth and Population Density in Monocultures of Larix leptolepis

One year-old Japanese larch (Larix leptolepis) seedlings were planted in a nursery from 1984 to 1986 at four density levels with four replicates in order to investigate the relationships between plant growth and density of survivors. As the results shown, self-thinning occurred severely in populations growing at high densities. The rate of the self-thinning followed a trajectory defined by the 3/2 power law. The relationship between mean dry weight per tree and population density at a given stage of growth followed the reciprocal equation and power equation at early experimental stages, but changed gradually to follow the 3/2 power law as plants grew further. Shch a change was mainly caused by the constant basal area per ms and decreased growth of tree height along a gradient of the density. The relationship between tree height (h) and density (p) also be discussed and in the 3/2 power law system it could be described by an equation consisting of h=αp（-1/2） where α is a constant.     

Change of thermal stability of colicin E7 triggered by acidic pH suggests the existence of unfolded intermediate during the membrane-translocation phase

Purified colicin E7 was analyzed by CD spectrum and gel filtration chromatography in a mimicking membrane-translocation phase. It was found that the CD spectra of colicin E7 at pH 7 and pH 2.5 were similar. Although the melting temperature of the protein shifted from 54.5°C to 34°C at low pH, the thermal denaturation curves of colicin E7 at different pH conditions still fit a two-state model. These experimental results imply that a minor structural change, triggered by acidic pH, for instance, may reduce the energy required for protein melting. In contrast to the minor change in secondary structure at different pH conditions, we observed that, in vitro, all monomeric colicin E7s converted into multimer-like conformations after recovering from the partial unfolding process. This multimeric form of colicin can only be dissociated by formamide and guanidine hydrochloride, indicating that this protein complex is indeed formed by aggregation of the monomeric colicins. Most interestingly, the aggregated colicins still perform in vivo bacteriocidal activity. We suggest that in a partial unfolding state the colicin is prepared for binding to the specific targets for translocation through the membrane. However, in the absence of specific targets in vitro these unfold intermediates may therefore aggregate into the multimeric form of colicins. Proteins 32:17–25, 1998. © 1998 Wiley-Liss, Inc.     

Phosphorus-31 nuclear magnetic resonance spectroscopy of human retinoblastoma cells: correlations with metabolic indices

The ³¹P nuclear magnetic resonance spectrum of cultured human Y-79 retinoblastoma cells was obtained at 121 MHz on intact cells trapped in agarose threads. The spectrum was dominated by monoester peaks, which varied in relative concentration from preparation to preparation. Resonances from phosphocreatine, phosphodiesters and diphosphodiesters also exhibited variability relative to ATP. The main monoester was identified as phosphorylcholine by ³¹P-NMR of perchloric acid extracts. It was determined that the changes in monoester concentration correlated with feeding pattern. Phosphorus spectra of cells 1,2 and 3 days post feeding showed a 40% decrese in the relative concentration of phosphorylcholine concentration over the 3 day period. Phosphocreatine, phosphodiesters and diphosphodiesters increased relative to ATP during the same period. Growth curve experiments and oxygen consumption measurements indicated that the decrease in phosphorylcholine correlated with a decrease in cellular growth and oxygen consumption. We conclude that monoester concentration may be a useful indicator of nutritional status in these cells and possibly in intact tumors.     

The utility of internally transcribed spacer 2 DNA sequences of the nuclear ribosomal gene for distinguishing sibling species of Trichogramma

The usefulness of the internally transcribed spacer 2 (ITS2) of the nuclear ribosomal gene complex is tested for providing taxonomic characters to identify Trichogramma species. The ITS2 sequences of a group of sibling species of the T. deion/T. pretiosum complexes were determined. A simple and precise identification key to the species of these assemblages was constructed using as taxonomic characters the size of the ITS2 and the difference in restriction length polymorphism of species with similarly sized ITS2. Individual wasps can be identified by amplification of their ITS2 with general primers, determining the size of the PCR product using standard agarose electrophoresis, followed in some species by a DNA-digestion with a restriction enzyme. Because this system works well for a number of closely related species we are hopeful that similar PCR-based identification can be extended to all species of the genus once their ITS2 sequences have been determined. The advantage of this identification system over the morphology-based system is that non-specialists are able to quickly and cheaply identify individual specimens. In addition, species specific primers were tested for the two most common species of these groups (i.e. T. pretiosum and T. deion). These primers can be used either as a direct identification tool or as a method to confirm the identification using the general key. The phylogeny of this group of wasps was also analyzed based on the ITS2 sequence.     

人体半导体激光外照射的疗效及其作用机理研究：血浆肽类神经递质 …

本工作应用半导体激光（６５０ｎｍ,１５－２０ｍＷ,ＣＷ）穴位照射人体双侧“扶突”穴后,同步观察其在血浆肽类神经递质上的变化以及其在血液黏度,免疫功能,抗氧化体系等方面的影响及其相关性。结果发现β－Ｅｐ有非常显著性的下降（Ｐ＜０．０２）,患者的ＮＫ细胞活性,在照射后即有所显著性地提高（Ｐ＜０．０５）。患者的超氧化物歧化酶（ＳＯＤ）亦有同步增加（Ｐ＜０．０５）。此外在血液流变学方面,发现血粘度指标中有     

记忆增强肽促进大鼠海马内CREB磷酸化

五肽ＺＮＣ（ＣＰＲ（ｐＢＧｌｕ－Ａｓｎ－Ｃｙｔ－Ｐｒｏ－Ａｒｇ－ＯＨ）是精氨酸加压素（ＡＶＰ）在脑内的天然酶解产物,具有促进学习记忆的中枢效应。为了进一步阐明其作用的分子机制,以整体大鼠海马及离体大鼠海马切片为对象,研究了ＺＮＣ（Ｃ）ＰＲ对ｃＡＭＰ反应元件结合蛋白（ＣＲＥＢ）磷酸化的作用。发现ＺＮＣ（Ｃ）ＰＲ及其类似物ＮＬＰＲ能诱导大鼠海马内ＣＲＥＢ磷酸２化,该作用能被其拮抗剂ＺＤＣ（Ｃ）ＰＲ、Ｇ     

Erebosis,a new cell death mechanism during homeostatic turnover of gut enterocytes

Many adult tissues are composed of differentiated cells and stem cells, each working in a coordinated manner to maintain tissue homeostasis during physiological cell turnover. Old differentiated cells are believed to typically die by apoptosis. Here, we discovered a previously uncharacterized, new phenomenon, which we name erebosis based on the ancient Greek word erebos (“complete darkness”), in the gut enterocytes of adult Drosophila. Cells that undergo erebosis lose cytoskeleton, cell adhesion, organelles and fluorescent proteins, but accumulate Angiotensin-converting enzyme (Ance). Their nuclei become flat and occasionally difficult to detect. Erebotic cells do not have characteristic features of apoptosis, necrosis, or autophagic cell death. Inhibition of apoptosis prevents neither the gut cell turnover nor erebosis. We hypothesize that erebosis is a cell death mechanism for the enterocyte flux to mediate tissue homeostasis in the gut.

It has been believed that gut enterocytes continuously die through apoptosis. However, this study shows that gut enterocytes die through a novel cell death mechanism, named erebosis. Erobotic cells lack the characteristic features of apoptotic, necrotic or autophagic cell death; instead they lose their cytoskeleton, cell adhesion and organelles, and their nuclei become flat and indistinct.