ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375608

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

A survey of 128 biotechnology core facilities has provided data on the finances, services, space requirements, and personnel. An average facility had four full‐time personnel and 7.5 major instrument systems, and occupied 969 sq. ft. Average total income was $244,000/year, but annual user fee income was only $125,000. Typically, facilities required substantial institutional support or grants. Cost recovery (user fee income divided by total income) averaged 49%. During the last 5 years user fee income, total income, and cost recovery have increased. In‐house charges for protein sequencing and peptide synthesis increased approximately 30%, while oligonucleotide synthesis charges decreased by 74%. The costs (charges corrected for subsidy from non‐user fee income) for most services did not significantly change, except that oligonucleotide synthesis costs decreased by 25% in 1992. DNA synthesis had the highest throughput per month (116 samples), followed by amino acid analysis (86 samples) and DNA sequencing (67 samples). Other services averaged from 5 to 60 samples. DNA synthesis and purification were the services used by the greatest number of principal investigators. A number of services including DNA sequencing, mass spectrometry, capillary electrophoresis, RNA synthesis, electroblotting, and carbohydrate analysis have been introduced in the last 3 years. Although these services are characterized by high levels of methods development and non‐user runs, they are offered by twice the percentage of facilities as in 1989, and are increasingly contributing to facility income.—Ivanetich, K. M., Niece, R. L., Rohde, M., Fowler, E., Hayes, T. K. Biotechnology core facilities: trends and update.FASEB J.7: 1109‐1114; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375609

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

Invertebrates comprise about 95% of animal species, yet most studies of extracellular matrices have centered on vertebrates. Comparative studies of invertebrates will enhance comprehension of evolutionary processes and appreciation of the diversity of extracellular matrices. Moreover, new functions and new structures will be revealed over a wide range of organismic needs. Another important perspective is that several invertebrate species have provided insight into developmental processes, and those processes often have direct relevance to vertebrate development. Thus, studies of fruit flies, nematodes, and sea urchins have revealed common features of cell biology, embryonic development, and matrix properties that pertain throughout the animal kingdom. The advantages of invertebrates are their rapid rates of embryonic development, their amenability to genetic manipulation, availability of innumerable mutants, and their ease of study in the laboratory. Extracellular matrices themselves are readily compared. Invertebrates display a wide diversity of such matrices, at the levels of both tissue architecture and molecular anatomy. Knowledge of that diversity leads to an appreciation of evolutionary variety and eventually to comprehension of the organization of extracellular matrices and of the properties of their constituent macromolecules. The expanding knowledge of unique matrix molecules from invertebrates also has economic potential and is beginning to provide new materials for biotechnology.—Har‐El, R., Tanzer, M. L. Evolution of the extracellular matrix in invertebrates.FASEB J.7: 1115‐1123; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375610

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

Nitric oxide is synthesized in mammalian cells froml‐arginine or from pharmaceutical drugs. It forms paramagnetic complexes with some metalloproteins, inhibiting key enzymes in DNA synthesis, mitochondrial respiration, iron metabolism, etc. This article reviews how electron paramagnetic resonance spectroscopy helps to detect unambiguously such specific molecular targets for NO in mammalian whole cells and organelles. EPR has also been used for the detection of spin adducts of free NO by spin‐trapping methods.—Henry, Y., Lepoivre, M., Drapier, J.‐C., Ducrocq, C., Boucher, J.‐L., Guissani, A. EPR characterization of molecular targets for NO in mammalian cells and organelles.FASEB J.7: 1124‐1134; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8397130

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

Reactive free radical species (R∗) are associated with several forms of tissue damage and disease, and also with the process of aging. Protection is thought to be available in the form of endogenous compounds that react with and thereby “scavenge” the R∗. Because many R∗are reactive forms of oxygen, an effective scavenger is often referred to as an antioxidant. To be an effective antioxidant physiologically, a substance must have certain chemical and biological properties: it must be present in adequate amounts in the body; it must react with a variety of R∗; it must be suitable for compartmentation; it must be readily available; it might be suitable for regeneration; it must be conserved by the kidneys; and it must have tolerable toxicity. Several water‐soluble candidates are mentioned, with most having no more than one or two of the attributes listed. Ascorbic acid is discussed in detail, and an analysis is made of whether it has the properties mentioned.—Rose, R. C., Bode, A. M. Biology of free radical scavengers: an evaluation of ascorbate.FASEB J.7: 1135‐1142; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375611

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

A mechanism that selectively cools the brain during hyperthermia is a well‐accepted fact in animals. Selective brain cooling (SBC) during hyperthermia has also been proposed in humans, but this suggestion has met with considerable debate. Several authors have rejected the idea of human SBC for the following reasons:1) SBC is illogical because this mechanism removes the error signal activating the defense against hyperthermia;2) unlike other animals, humans do not pant and thus do not possess a powerful heat sink at a short distance from the brain;3) humans do not have a carotidrete, the countercurrent heat exchanger between the arterial and venous bloods flowing in and out of the brain;4) the high and constant arterial blood flow of the brain is sufficient to cool the brain under all conditions; and5) the relatively low tympanic temperature (Tty) recorded in hyperthermic humans is not a sign of SBC, but rather is the sign of contamination of Ttyby a low head skin temperature. These arguments are reviewed and rejected and results of several recent experiments are summarized. Finally, recent experimental articles that contradict the existence of human SBC or the validity of Ttyare discussed and their conclusions refuted. This review points to overwhelming evidence in favor of human SBC.—Cabanac, M. Selective brain cooling in humans: “fancy” or fact?FASEB J.7: 1143‐1147; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375612

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

Humans, compared to other species, have exceptional capability for dissipation of heat from the entire skin surface. We can secrete more than two liters per hour of sweat, indefinitely. The corresponding potential for evaporative cooling is near a thousand watts, sufficient to compensate for the extreme high levels of heat production during exercise. Also, the blood vessels of our skin have exceptional capability to dilate and deliver heat to the body surface. These are our special adaptations for thermal stress. They allow prolonged heavy exercise with modest elevations in the temperature of the fluid that cools all the internal organs, not just the brain‐arterial blood. The vascular architecture of the human head is radically different from that of animals that exhibit SBC. These species have special adaptations that reflect their dependence on respiratory evaporation, particularly the limitation imposed on capability to dispose of heat produced during exercise. The increase in blood temperature in an intense sprint would heat the well‐perfused brain rapidly. But the heat exchange over the large surface area of contact between a venous plexus cooled by respiratory evaporation and the meshwork of arterial vessels in the carotid rete precools blood bound for the brain. Specialized cooling of the brain (SBC) has not been demonstrated by direct measurements in humans. Changes in tympanic temperature (Tty) are taken as evidence for SBC. This continues an unfortunate tradition of exaggeration of the significance of Tty. In the only direct measurements available, brain temperature was unaffected by fanning the face although Tty did fall. What may appear to be a remnant of the carotid rete heat exchanger in humans is the intimate association between a short segment of the internal carotid artery and the plexus of veins in the cavernous sinus. Fortunately, the brain need not rely for its cooling on countercurrent heat exchange across this small surface area of contact. In humans, SBC stands for skin: the body cooler—we use our entire skin surface for heat dissipation.—Brengelmann, G. L. Specialized brain cooling in humans?FASEB J.7: 1148‐11.53; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375613

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

To increase our understanding of the molecular basis for antibody specificity and for the cross‐reactivity of anti‐peptide antibodies with native proteins it is important to study the three‐dimensional structure of antibody complexes with their peptide antigens. For this purpose it may not be necessary to solve the structure of the whole antibody complex but rather to concentrate on elucidating the combining site structure, the interactions of the antibody with its antigen and the bound peptide conformation. We have developed an NMR methodology based on two‐dimensional difference spectrum measurements which extract the information concerning antibody‐peptide interactions and intramolecular interactions in the bound ligand from the crowded and unresolved spectrum of the Fab complex. These measurements yield restraints on interproton distances in the complex which are used to dock the peptide into calculated models for the antibodies' combining sites. Comparison of the interactions of three antibodies against a cholera toxin peptide (CTP3), which differ in their cross‐reactivity with the toxin, yields information about the size and conformation of antigenic determinants recognized by antibodies, the structure of their combining sites and relationships between antibodies' primary structure, and their interactions with peptide antigens.—Anglister, J., Scherf, T., Zilber, B., Levy, R., Zvi, A., Hiller, R., Feigelson, D. Two‐dimensional NMR investigations of the interactions of antibodies with peptide antigens.FASEB J.7: 1154‐1162; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375614

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

New software for microcomputers enables predictive, quantitative models of genetic systems to be produced that can account for the elements of time, scale, and feedback control of hierarchical systems. The flow of genetic information during protein synthesis can be addressed by treating each intermediate as a kinetic element in a linked series of reactions. When the rate of transcription changes, the time required to achieve a new level of the encoded protein is expected to be a function of the conversion rates or half‐lives of all intermediates. Kinetic modeling may be used to make predictions and integrate primary data concerning rates of transcription, nuclear mRNA dynamics, nucleocytoplasmic transport, translational control, and other processes that govern the rate of synthesis for specific proteins.—Hargrove, J. L., Microcomputer‐assisted kinetic modeling of mammalian gene expression.FASEB J.7: 1163‐1170; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375615

出版商:Wiley    

年代:1993

数据来源: WILEY

摘要:

Neither the physiological function of sigma (σ) receptors nor the cellular mechanism responsible for the pharmacological effects ofσreceptor ligands is known. We now report thatσreceptor ligands noncompetitively inhibit nicotine‐stimulated catecholamine release from bovine adrenal chromaffin cells in a concentration‐dependent and reversible manner. The rank order of potency of ligands to inhibit nicotine‐stimulated catecholamine release is significantly correlated (P<0.005) with that observed in radioligand binding assays selective for theσ1receptor subtype. This naltrexone‐insensitive effect is paralleled by an inhibition of nicotine‐stimulated increases in [Ca2+]i. Sigma ligands were without effect on catecholamine release or [Ca2+]iin the absence of nicotine. In addition, nicotine accelerated the association of theσreceptor selective radioligand, [3H](+)pentazocine, to adrenal medullary homogenates while having no effect on the rate of ligand dissociation, consistent with aσligand binding site closely associated with and allosterically modulated by the nicotinic acetylcholine receptor. Thus, the actions of agonists at the nicotinic acetylcholine receptor in bovine chromaffin cells are modulated byσ1receptor selective ligands.—Paul, I. A., Basile, A. S., Rojas, E., Youdim, M. B. H., De Costa, B., Skolnick, P., Pollard, H. B., Kuijpers, G. A. J. Sigma receptors modulate nicotinic receptor function in adrenal chromaffin cells.FASEB J.7: 1171‐1178; 1993.

ISSN:0892-6638    

DOI:10.1096/fasebj.7.12.8375616

出版商:Wiley    

年代:1993

数据来源: WILEY