A specific microassay for evaluating hepatic LDH activity in co-cultures of hepatocytes with other cells

This study describes the development of a simple, rapid and reproducible microassay for determining the intracellular LDH activity of rat hepatocytes present in a co-culture system with other cells. The procedure involves treatment of cellular homogenates with an anti-LDH antiserum that specifically inhibits the LDH activity of rat hepatocytes. The assay is performed in 96-well plates and LDH activity can be measured directly in the same wells using a colorimetric method. The difference in LDH activity values measured before and after antiserum incubation reflects the LDH content of the hepatocytes in the sample. The advantages of this method are the small number of cells required, a reduction in sample handling and the possibility of differentiating LDH activity in hepatic and non-hepatic cells. The possible applications of this technique as a parameter for biochemical data and as a test for cytotoxicity studies in co-cultures are also discussed.     

Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes,Plant Organs and Senegalese Sample Locations

The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 – 55.8%) and non‐terpenic oxygenated compounds (34.5 – 63.1%). The main components were (E)‐β‐ocimene (12.1 – 39%), octyl acetate (11.6 – 21.8%) and decanol (9.7 – 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil.     

C-banding polymorphism and the analysis of nucleolar activity in Dasypyrum villosum (L.) Candargy,its added chromosomes to hexaploid wheat and the amphiploid Triticum dicoccum — D. villosum

Summary C-banding patterns and nucleolar activity were analyzed in Dasypyrum villosum, its added chromosomes to hexaploid wheat and the hexaploid amphiploid Triticum dicoccum-D. villosum. Two different populations of the allogamous species D. villosum (2n= 14, VV) from Greece and Italy were analyzed showing a similar polymorphism for C-banding pattern. Six of the seven addition lines were identified by their characteristic C-banding pattern. No polymorphism between both members of each added alien chromosome was found. Furthermore, nucleolar activity and competition were studied by using silver staining procedure. In D. villosum only one chromosome pair, A, was found to be responsible for organizing nucleoli. The results obtained in the amphiploid and in the addition lines demonstrate that nucleolar activity is restricted to SAT-chromosomes 1B and 6B of wheat, while those of D. villosum remain inactive.     

大丁草属植物的化学成分和药理活性研究

本文概述了大丁草属植物的化学成分和药理活性研究。着重介绍了其中所含的香豆素类化合物的化学结构特点、光谱特征及生物活性。     

昆虫抗菌肽及其基因工程研究进展

昆虫抗菌肽是昆虫免疫后存在于血淋巴中的一类活性肽,具有广谱的抗菌、抗病毒、抑制肿瘤的生物活性,具有很高的应用潜力。本文主要介绍昆虫抗菌肽的类型、生理活性、基因的克隆与表达及转基因工程研究进展。 Insect Antibacterial Peptides and Its Progress in Advance on Genetic Engineering GONG Xia,YUE Guo-wei,SHI Yong-hui Laboratory for Animal Nutrition Research,College of Food Science,Southern Yangtze University,Wuxi 214036,China Abstract:Insect antibacterial peptides produced are kinds of bioactive peptides in hameolymph hen insect has been immunized.These peptides have the wide range of antibacterial,antiviral spectrum and inhibiting growth of tumor cell.The types of antibacterial peptides and its physiological activities,cloning and expression of the genes and transgenetic research are summarized.Its application on medicine and gene engineering are prospected. Key words：insect antibacterial peptides; physiological activity; gene     

Reproductive cycle of the European clam Ruditapes decussatus from Óbidos Lagoon,Leiria, Portugal

ABSTRACT

In Portugal, the European clam (Ruditapes decussatus) is an important commercial resource. Óbidos Lagoon is a strong candidate as a cultivation area to increase European clam exploitation. However, the reproductive biology of this population has not been described. In this work, the reproductive cycle of R. decussatus was characterized by determining gonadal development stages, gonad index, condition index, and biochemical composition. The relationship between reproduction and environmental parameters (sea surface temperature, chlorophyll a, and particulate organic matter) was assessed. Ruditapes decussatus had an annual reproductive cycle. The gametogenic cycle started in late winter, and the ripe stage in spring was followed by spawning that began at the end of spring/early summer and extended until early autumn. The subsequent period of sexual rest occurred during the winter. Condition index showed seasonal variations related to food availability (chlorophyll a). The European clams in Óbidos Lagoon recovered rapidly after their reproductive period, most likely owing to the availability of food. This study will help to improve sustainable management of this wild stock and is important for future aquaculture development of this species.     

Nematocidal activity of 6-O-octanoyl- and 6-O-octyl-d-allose against larvae of Caenorhabditis elegans

ABSTRACT

The nematocidal activities of the fatty acid esters of d-allose were examined using the larvae of C. elegans. Among the fatty acid esters, 6-O-octanoyl-d-allose (3) showed significant activity. 6-O-octanoyl-d-glucose (5) showed no activity, indicating that the D-allose moiety is essential for the nematocidal activity of 3. A nonhydrolyzable alkoxy analog 6-O-octyl-d-allose (6) also showed activity equivalent to that of 3.     

Effect of monogalactosyldiacylglycerol on the interaction between photosystem II core complex and its antenna complexes in liposomes of thylakoid lipids

The non-bilayer lipid monogalactosyldiacylglycerol (MGDG) is the most abundant type of lipid in the thylakoid membrane and plays an important role in regulating the structure and function of photosynthetic membrane proteins. In this study, we have reconstituted the isolated major light-harvesting complexes of photosystem II (PSII) (LHCIIb) and a preparation consisting of PSII core complexes and minor LHCII of PSII (PSIICC) into liposomes that consisted of digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG), with or without MGDG. Transmission electron microscopy and freeze-fracture studies showed unilamellar proteoliposomes, and demonstrated that most of the MGDG is incorporated into bilayer structures. The impact of MGDG on the functional interaction between LHCIIb and PSIICC was investigated by low temperature (77 K) fluorescence emission spectra and the photochemical activity of PSII. The additional incorporation of LHCIIb into liposomes containing PSIICC markedly increased oxygen evolution of PSIICC. Excitation at 480 nm of chlorophyll (Chl) b in LHCIIb stimulated a characteristic fluorescence emission of the Chl a in PSII (684.2 nm), rather than that of the Chl a in LHCIIb (680 nm) in the LHCIIb–PSIICC proteoliposomes, which indicated that the energy was transferred from LHCIIb to PSIICC in liposome membranes. Increasing the percentage of MGDG in the PSIICC–LHCIIb proteoliposomes enhanced the photochemical activity of PSII, due to a more efficient energy transfer from LHCIIb to PSIICC and, thus, an enlarged antenna cross section of PSII.     

Delineation of the calcineurin-interacting region of cyclophilin B

The immunosuppressant drug cyclosporin A (CsA) inhibits T-cell function by blocking the phosphatase activity of calcineurin. This effect is mediated by formation of a complex between the drug and cyclophilin (CyP), which creates a composite surface able to make high-affinity contacts with calcineurin. In vitro, the CyPB/CsA complex is more effective in inhibiting calcineurin than the CyPA/CsA and CyPC/CsA complexes, pointing to fine structural differences in the calcineurin-binding region. To delineate the calcineurin-binding region of CyPB, we mutated several amino acids, located in two loops corresponding to CyPA regions known to be involved, as follows: R76A, G77H, D155R, and D158R. Compared to wild-type CyPB, the G77H, D155R, and D158R mutants had intact isomerase and CsA-binding activities, indicating that no major conformational changes had taken place. When complexed to CsA, they all displayed only reduced affinity for calcineurin and much decreased inhibition of calcineurin phosphatase activity. These results strongly suggest that the three amino acids G77, D155, and D158 are directly involved in the interaction of CyPB/CsA with calcineurin, in agreement with their exposed position. The G77, D155, and D158 residues are not maintained in CyPA and might therefore account for the higher affinity of the CyPB/CsA complex for calcineurin.