The relationships among physical,geometrical and mechanical properties of bone,with a note on the properties of nonhuman primate bone

Since bone reacts to imposed loads by formation and resorption of tissue, analysis of tissue distribution within a bone provides evidence of the adaptation of that bone to a given mechanical function. Definition of these structure-function relationships permits the physical anthropologist to clarify the wide variety of behavioral/morphological adaptations to specific ecological niches in extant primates. From this information, behavior and locomotor function can ultimately be inferred in fossil primates. This paper reviews research which shows the relationships between the physical, geometrical and mechanical properties of bone, so that researchers who are investigating the properties of bone are aware of the numerous interpretations which may be made about structure and function from basic data. In addition, this paper is an attempt to apprise investigators working with primates that comparative data on the properties of primate bone are available, though sparse.     

Effect of the methodology on peptide amino acid concentrations in blood and plasma of sheep

Different methodologies for the measurement of peptide amino acid (PAA) in blood and plasma were compared in sheep. Preparation of blood and plasma samples consisted of a deproteinization, either chemical with sulfosalicylic acid (0.04 g for 1 ml of sample) or physical by ultrafiltration (10,000‐MW cut‐off filters), with or without a subsequent ultrafiltration through a 3,000‐MW cut‐off filter. Peptide concentrations were determined by quantification of amino acid concentrations before and after acid hydrolysis of samples. Free amino acid concentrations were similar by all the method used (about 2.5 and 2.7mM, for blood and plasma respectively). Peptide concentrations were higher with chemical deproteinization (10.6 and 4.2 mM, for blood and plasma respectively) than with physical deproteinization (5.7 and 3.3 mM, for blood and plasma respectively). When the deproteinized samples were further treated to remove material of molecular weight above than 3 kDa, peptide concentrations were significantly reduced, which indicates inefficiencies in the ability of the deproteinizing procedures in removing all the proteinaceous materials. Concentration of small PAA (< 3kDa) in blood was about 1.5‐fold that in plasma, mainly due to peptide Gly and Glu derived from the hydrolysis of the erythrocyte glutathione. The choice of a methodology for quantifying circulating peptides is discussed.     

Effect of the Methodology on Circulating Peptides Determination and Consequences on Net Flux Measurements Across the Gastrointestinal Tract of Sheep

Two methodologies for the measurement of peptide amino acids (PAA) in blood were compared to evaluate their effects on the measurement of the net flux of peptides across the gastrointestinal tract of sheep. These methods consisted of a chemical deproteinization of blood samples with sulfosalicylic acid (1.6M, 0.1 ml for 1 ml of sample) or perchloric acid (1M, 1 ml for 1 ml of sample) followed by ultrafiltration through a 3,000-Da cut-off filter (SSA+UF3kD) or gel filtration through a Sephadex G-15 column (1,500-Da cut-off filter; PCA+G-15), respectively, prior to PAA analysis. Peptide concentrations as determined by amino acid concentrations before and after hydrolysis of samples were slightly greater with the SSA+UF3kD (991 µM) than with the PCA+G-15 (605 µM) methodology. However, both methodologies gave similar net portal-drained viscera flux data in sheep fed on alfalfa pellets with histidine as the only significant uptake of peptide amino acid.     

蛇毒蛋白原核表达包涵体复性研究进展

外源基因在大肠杆菌中表达后常形成不溶性的无活性包涵体。包涵体的形成已经成为研究和应用活性蛋白质生产的主要障碍。然而,在合适的条件下,包涵体经过溶解、纯化、复性过程后可在体外重新折叠成有活性的蛋白质。迄今,已对蝰科、眼镜蛇科11种毒蛇的18个基因(包括金属蛋白酶、PLA₂、β-银环蛇毒素、心脏素素、丝氨酸蛋白酶、神经生长因子、C-型凝集素等)成功进行了原核表达,采用稀释复性、透析复性和层析复性三种方法成功进行了包涵体复性。着重就蛇毒蛋白原核表达后包涵体复性所用的方法予以综述。     

A [P]NAD-based method to identify and quantitate long residence time enoyl-acyl carrier protein reductase inhibitors

The classical methods for quantifying drug–target residence time (t_R) use loss or regain of enzyme activity in progress curve kinetic assays. However, such methods become imprecise at very long residence times, mitigating the use of alternative strategies. Using the NAD(P)H-dependent FabI enoyl-acyl carrier protein (enoyl-ACP) reductase as a model system, we developed a Penefsky column-based method for direct measurement of t_R, where the off-rate of the drug was determined with radiolabeled [adenylate-³²P]NAD(P⁺) cofactor. In total, 23 FabI inhibitors were analyzed, and a mathematical model was used to estimate limits to the t_R values of each inhibitor based on percentage drug–target complex recovery following gel filtration. In general, this method showed good agreement with the classical steady-state kinetic methods for compounds with t_R values of 10 to 100 min. In addition, we were able to identify seven long t_R inhibitors (100–1500 min) and to accurately determine their t_R values. The method was then used to measure t_R as a function of temperature, an analysis not previously possible using the standard kinetic approach due to decreased NAD(P)H stability at elevated temperatures. In general, a 4-fold difference in t_R was observed when the temperature was increased from 25 to 37 °C.     

Evaluation of instream habitat enhancement options using fish habitat simulations: case-studies in the river Pas (Spain)

In the northern coast of Spain there are rivers with Atlantic salmon populations. In the upper reaches of one of these streams, river Pas, the effectiveness of habitat enhancement measures was evaluated, under different instream flow conditions. By means of the Instream Flow Incremental Methodology and using a two dimensional hydraulic model (River2D, Steffler P (2000) Software River2D. Two Dimensional Depth Averaged Finite Element Hydrodynamic Model. University of Alberta, Canada), the potential value of stream habitat for different salmon development stages requirements was measured by Weighted Useable Area (WUA). This habitat evaluation was carried out for the unmodified stream reach, which represent the control or natural conditions. Habitat improvement measures (alternate deflectors and low dams) were simulated in the original riverbed topography. Over this modified base, habitat was estimated running River2D again. By comparing the salmon habitat evaluations in the control conditions with those obtained under those improvement conditions we have been able to assess the effectiveness of each one, and the instream flow environment at which maximum improvement is reached. The maximum habitat improvement was obtained around 10 m³/s for the adult salmon, and for the fry and parr it was around 6 m³/s. However, the habitat simulation results show that with both improvement measures, under a natural flow regime the mean annual habitat increases around 1% of the WUA in relation to the control conditions, which is not a significant improvement. A similar small WUA increase was obtained when changing the bed topography, considering geomorphological adjustments due to the new erosion and sedimentation areas caused by the presence of these structures. Therefore, these types of habitat improvement measures are not recommended in these stream reaches.     

响应面法优化洋葱假单胞菌产脂肪酶液体发酵工艺

用响应面法对洋葱假单胞菌G-63液体发酵产脂肪酶条件进行了优化。首先运用单因子试验筛选出麦芽糖和豆粉水解液为最适碳源和氮源。在此基础上,通过Plackett-Burman设计试验,对影响产酶条件的11个相关因子进行评估并筛选出具有显著效应的3个因子:橄榄油、豆饼粉水解液以及初始pH值。在用最陡爬坡实验逼近以上3个因子的最大响应区域后,采用响应面分析法,确定出橄榄油、豆粉水解液的最佳浓度和最佳初始pH值分别为4.337%,1.956%和8.38。优化后液体发酵培养基中脂肪酶活力提高到44.39 U/mL,比初始酶活13.45 U/mL提高了3.3倍。     

The anthropological value of minor variants of the dental crown

The incidences of 31 minor variants of the dental crown were scored from dental casts of samples taken from six European populations. Although several variants showed significant sex bias in one or other sample, only one (pits instead of furrow on premolar₂) consistently favoured one sex. Associations between the variants were sought. Although few consistent associations were demonstrated, there was a possible tendency for extra cusps to occur together throughout the dentition. Distance statistics calculated between the samples were compatible with the expected genetical relationships of the samples, but only modern samples could be used since variants were destroyed by attrition in archeological samples. Before such distances can be considered reliable, it is necessary to know:

• i the extent to which environmental factors such as diet influence variant expression.
• ii whether or not variant bearing teeth are selectively destroyed by caries, which in civilised populations render a high proportion of most dentitions unscoreable.

     

Linked effects of dam-released floods and water temperature on spawning of the Clanwilliam yellowfish Barbus capensis

In South Africa, modified flow regimes designed to maintain ecosystem functioning at some pre-determined level are recommended for all rivers involved in major water-resource developments. One component of such flow regimes of special interest in the winter-rainfall region of the country is the small pulses of higher flow that occur in the dry season (November–April), here called freshes. Research was carried out in the Olifants River, in the winter-rainfall region of South Africa, on the link between freshes and spawning of an endemic, vulnerable cyprinid, the Clanwilliam yellowfish Barbus capensis. Experimental releases from Clanwilliam Dam on the Olifants River in a previous year showed that a greater than usual spawning success, assessed by larval recruitment levels, was correlated with hypolimnetic freshes released during the species' breeding season (October–January). In the study reported on here, a hypolimnetic fresh of the same size, duration and timing as those linked with successful spawning failed to induce spawning. Differences in the thermal regime of water releases appeared to be responsible. Two warm (19–21 °C), epilimnetic freshes of 15 hours duration were then released, and correlated with fish moving onto the spawn beds and exhibiting pre-spawning behaviour. However, the fish moved downstream away from the spawn beds when cold (16–18 °C) hypolimnetic baseflows were released for 15 hours between the two epilimnetic freshes and continually after the second one. The presence of free embryos and larval B. capensis indicated, from their developmental stages, that spawning had probably occurred before the experimental releases began, when warm (21–23 °C) epilimnetic water was spilling over the dam, and had halted once spillage stopped and hypolimnetic releases began. Indeed, the presence of dead and deformed young suggested that the cold water may have had a detrimental affect on those spawned during the earlier warmer spell. A summary table details the conditions, including the hydraulic characteristics of the spawn beds, believed to induce spawning and support early life stages of B. capensis. It is concluded that freshes released from Clanwilliam Dam at the appropriate time (October–January) should be able to increase spawning success of B. capensis, but only if the water temperature at the spawn site is at or above 19 °C and stable or rising. However, successful spawning will not necessarily lead to high recruitment if water temperatures are not then maintained at appropriate levels for some time for development of the embryos and larvae. This implies that additional epilimnetic releases will be required following critical trigger flows.     

植物蛋白电泳分析的方法学研究及技术改进

本文在采用多种方法进行植物蛋白质电泳分析的基础之上,对植物蛋白进行了电泳分析的方法学研究,论述了多种电泳技术的理论概要、关键步骤、实验要领及我们的一些改进。