Characterization of microsomal and mitochondrial phospholipase D activities and cloning of a phospholipase D alpha cDNA from strawberry fruits.

Phospholipase D alpha (PLD, EC 3.1.4.4)) is a key enzyme involved in membrane deterioration that occurs during fruit ripening and senescence. The biochemical and molecular characteristics of PLD was studied in strawberry (Fragaria ananassa Duch) fruits, which are non-climacteric fruits. PLD activity was primarily associated with the mitochondrial and microsomal fractions and showed increased activity during development. Optimal pH levels of activity were observed at 5.5 and 6.5 for mitochondrial PLD and at 5 and 7 for microsomal PLD. Calcium enhanced microsomal PLD activity at 1-40 microM levels. PLD activity followed Michaelis-Menten kinetics. Lineweaver-Burk analysis gave Km values in the range of 114 and 277 microM using dipalmitoylphosphatidylcholine (DPPC) as substrate for mitochondrial and microsomal PLD, respectively. The Vmax value for the microsomal PLD was nearly 12-fold higher than that of mitochondrial PLD. A 2874 bp full-length cDNA for PLD alpha was amplified from strawberry fruit mRNA using RT-PCR and 5'- and 3'-RACE encoding an 810 amino acid-polypeptide. The predicted strawberry PLD sequence showed the characteristic C2 domain and the phospholipase domains conferring calcium sensitivity and the enzyme activity, respectively. The strawberry PLD alpha showed a high degree of similarity to other PLD alphas from plants. The implications of PLD regulation during ripening of fruits are discussed.     

Verlauf der Körperwärme von Frettchen (Putorius furo L.) während der Trächtigkeit bei verschiedener Aussentemperatur

Zusammenfassung In fünf Fällen von Trächtigkeit bei Frettchen, die unter konstant 10, 20 und 35° gehalten wurden, konnte die Rektaltemperatur in 2 cm Tiefe von Tag zu Tag gemessen werden. Zusammenfassend läßt sich heute folgendes sagen:Man kann nach dem Verhalten der Körpertemperatur zwei Abschnitte der Trächtigkeit unterscheiden. Im ersten hält sich die Rektaltemperatur im Durchschnitt über dem Mittel des nichtträchtigen Zustandes (0,25 bis 0,41°), im zweiten sinkt sie unter dasselbe (um 0,11–0,41°). Im ganzen genommen zeigt die durchschnittliche Rektaltemperatur während der Trächtigkeit keinen nennenswerten Unterschied gegenüber der im nichtträchtigen Zustand.Der Abfall wird ziemlich genau um die Mitte der Tragdauer bemerkbar. Er ist am stärksten bei hoher Außentemperatur (im Mittel rund 0,7° bei 35°), am geringsten vermutlich bei tiefer (rund 0,2°- bei 10°). Übereinstimmend damit fand sich die größte Schwankungsbreite (2,7°) der Rektaltemperatur (während der Trächtigkeit) bei hoher Außentemperatur.In der vorletzten Trächtigkeitswoche ist ein leichter Anstieg der Körpertemperatur zu erkennen (im Mittel 0,06–0,52°); er hält bis etwa 3 Tage vor der Geburt an.Darauf folgt abermals eine deutliche Senkung der Körpertemperatur bis auf eine vorher kaum erreichte Tiefe.Während des mehrtägigen Wiederanstiegs findet die Austreibung statt. Dieser Anstieg dürfte bis nahe an die obere physiologische Grenze der Körpertemperatur führen und kann — offenbar ohne Beziehung zur Außentemperatur — Sprunghöhen bis zu 3,2° erreichen.Ein Auszug dieser Arbeit erschien unter dem Titel: Mitteilungen aus der Biol. Versuchsanstalt usw. Nr. 180 im Akad. Anzeiger Wien, Nr. 26, vom 10. Dez. 1931.     

Phosphorus supply drives rapid turnover of membrane phospholipids in the diatom Thalassiosira pseudonana

In low-phosphorus (P) marine systems, phytoplankton replace membrane phospholipids with non-phosphorus lipids, but it is not known how rapidly this substitution occurs. Here, when cells of the model diatom Thalassiosira pseudonana were transferred from P-replete medium to P-free medium, the phospholipid content of the cells rapidly declined within 48 h from 45±0.9 to 21±4.5% of the total membrane lipids; the difference was made up by non-phosphorus lipids. Conversely, when P-limited T. pseudonana were resupplied with P, cells reduced the percentage of their total membrane lipids contributed by a non-phosphorus lipid from 43±1.5 to 7.3±0.9% within 24 h, whereas the contribution by phospholipids rose from 2.2±0.1 to 44±3%. This dynamic phospholipid reservoir contained sufficient P to synthesize multiple haploid genomes, suggesting that phospholipid turnover could be an important P source for cells. Field observations of phytoplankton lipid content may thus reflect short-term changes in P supply and cellular physiology, rather than simply long-term adjustment to the environment.     

CHANGES IN CHEMICAL, SENSORY AND RHEOLOGICAL CHARACTERISTICS OF MANCHEGO CHEESES DURING RIPENING

Manchego cheese is a high-fat pressed ewe's-milk cheese made in Castilla-La Mancha (Spain) and produced by enzymatic coagulation. The minimum ripening time before marketing required by the Regulatory Board of the Manchego Cheese Appellation of Origin is 60 days.
This paper describes the physicochemical, proteolysis, sensory and texture characteristics of Manchego cheese, and the degree of homogeneity of cheeses made under the Manchego Appellation of Origin. The data gathered in this study indicate that sensory and instrumental analysis are useful tools for detecting changes in Manchego cheese during ripening. These changes were first detected by the instrumental analysis (2 months). The panelists detected differences after 4 months' ripening in all the factories. With physicochemical analysis, on the other hand, longer ripening times (6–8 months) are required before such changes become appreciated.     

Targeting HER2: A report on the in vitro and in vivo pre-clinical data supporting trastuzumab as a radioimmunoconjugate for clinical trials

The potential of the HER2-targeting antibody trastuzumab as a radioimmunoconjugate useful for both imaging and therapy was investigated. Conjugation of trastuzumab with the acyclic bifunctional chelator CHX-A″-DTPA yielded a chelate:protein ratio of 3.4 ± 0.3; the immunoreactivity of the antibody unaffected. Radiolabeling was efficient, routinely yielding a product with high specific activity. Tumor targeting was evaluated in mice bearing subcutaneous (s.c.) xenografts of colorectal, pancreatic, ovarian and prostate carcinomas. High uptake of the radioimmunoconjugate, injected intravenously (i.v.), was observed in each of the models and the highest tumor %ID/g (51.18 ± 13.58) was obtained with the ovarian (SKOV-3) tumor xenograft. Specificity was demonstrated by the absence of uptake of ¹¹¹In-trastuzumab by melanoma (A375) s.c. xenografts and ¹¹¹In-HuIgG by s.c. LS-174T xenografts. Minimal uptake of i.v. injected ¹¹¹In-trastuzumab in normal organs was confirmed in non-tumor-bearing mice. The in vivo behavior of ¹¹¹In-trastuzumab in mice bearing intraperitoneal (i.p.) LS-174T tumors resulted in a tumor %ID/g of 130.85 ± 273.34 at 24 h. Visualization of tumor, s.c. and i.p. xenografts was achieved by γ-scintigraphy and PET imaging. Blood pool was evident as expected but cleared over time. The blood pharmacokinetics of i.v. and i.p. injected ¹¹¹In-trastuzumab was determined in mice with and without tumors. The data from these in vitro and in vivo studies supported advancement of radiolabeled trastuzumab into two clinical studies, a Phase 0 imaging study in the Molecular Imaging Program of the National Cancer Institute and a Phase 1 radioimmunotherapy study at the University of Alabama.Key words: monoclonal antibody, HER2, trastuzumab, radioimmunodiagnosis, radioimmunotherapy     

A high level interface to SCOP and ASTRAL implemented in Python

Background  

Benchmarking algorithms in structural bioinformatics often involves the construction of datasets of proteins with given sequence and structural properties. The SCOP database is a manually curated structural classification which groups together proteins on the basis of structural similarity. The ASTRAL compendium provides non redundant subsets of SCOP domains on the basis of sequence similarity such that no two domains in a given subset share more than a defined degree of sequence similarity. Taken together these two resources provide a 'ground truth' for assessing structural bioinformatics algorithms. We present a small and easy to use API written in python to enable construction of datasets from these resources.     

FREE CHOICE PROFILING OF CHILEAN GOAT CHEESE

Different goat cheeses from Chile were studied by Free-Choice Profile (FCP) analysis. Generalized Procrustes Analysis (GPA) applied to FCP data permitted differentiation between samples and informed on the attributes responsible for the observed differences. Appearance was a dominant factor in discriminating samples and to a lesser degree textural variables were also correlated with GPA dimensions. In acceptability the fresh cheeses were significantly preferred over the ripened ones.     

莱茵衣藻Nfr-4突变株中类胡萝卜素含量的变化及其对藻生长的影响

文章对相同条件下培养的莱茵衣藻野生型CC-137和八氢番茄红素脱氢酶(phytoene desaturase,PDS)基因突变株Nfr-4的生长进行分析;并用反相高效液相色谱分析总有色类胡萝卜素以及叶绿素含量变化,结果表明两者生长的差异明显;Nfr-4突变株的单细胞叶绿素和总有色类胡萝卜素含量高于野生型CC-137的。     

Phloem flow and sugar transport in Ricinus communis L. is inhibited under anoxic conditions of shoot or roots

Anoxic conditions should hamper the transport of sugar in the phloem, as this is an active process. The canopy is a carbohydrate source and the roots are carbohydrate sinks. By fumigating the shoot with N₂ or flooding the rhizosphere, anoxic conditions in the source or sink, respectively, were induced. Volume flow, velocity, conducting area and stationary water of the phloem were assessed by non‐invasive magnetic resonance imaging (MRI) flowmetry. Carbohydrates and δ¹³C in leaves, roots and phloem saps were determined. Following flooding, volume flow and conducting area of the phloem declined and sugar concentrations in leaves and in phloem saps slightly increased. Oligosaccharides appeared in phloem saps and after 3 d, carbon transport was reduced to 77%. Additionally, the xylem flow declined and showed finally no daily rhythm. Anoxia of the shoot resulted within minutes in a reduction of volume flow, conductive area and sucrose in the phloem sap decreased. Sugar transport dropped to below 40% by the end of the N₂ treatment. However, volume flow and phloem sap sugar tended to recover during the N₂ treatment. Both anoxia treatments hampered sugar transport. The flow velocity remained about constant, although phloem sap sugar concentration changed during treatments. Apparently, stored starch was remobilized under anoxia.