Production of a biologically active novel goldfish growth hormone in Escherichia coli

Goldfish pituitary contains two types of growth hormones. One with five cysteine residues (type-I) similar to other Cyprinid GHs, and the other with four Cys residues (type-II) similar to those of other fish and tertapod species. Recombinant goldfish type II GH (gfGH-II) was produced in Escherichia coli using the pRSETB expression vector. The gfGH-II was produced fused to a leader sequence, which sequestered into inclusion bodies after expression. The inclusion bodies were solubilized using sodium hydroxide and the fusion protein purified by chelating affinity chromatography. Subsequently, gfGH-II was cleaved and analyzed by Western blotting, using a specific antiserum. For comparison we also produced recombinant common carp GH (cGH) which has 95% similarity to gfGH-II, and tested their growth promoting activity in goldfish. Both forms of GH significantly increased the growth rate of goldfish (P<0.05), although cGH was found to have a somewhat higher potency than gfGH-II.     

The effects of socioeconomic status on endochondral and appositional bone growth,and acquisition of cortical bone in children from 19th century Birmingham,England

Endochondral growth, appositional growth, and acquisition of cortical bone thickness in the femur are investigated in subadult skeletons (N = 43, dental age range birth to 12 years) from the 19^th‐century AD burial site of St. Martin's churchyard, Birmingham, England. Endochondral growth is monitored using diaphyseal femoral length. Appositional growth is monitored using radiographic midshaft mediolateral width and acquisition of cortical bone using combined mediolateral cortical thickness measured at the midshaft from radiographs. The methodology involves plotting these variables against dental age. Growth is compared in children of differing socioeconomic status. Higher and lower status individuals are identified in the assemblage by their burial in brick vaults in the case of the former and in earth‐cut graves in the case of the latter. The relationships between bone dimensions and dental age are described using a polynomial regression procedure, and analysis of regression residuals is used to evaluate differences in bone dimension‐for‐dental age between the two status groups. Results show that lower socioeconomic status individuals had lower cortical thickness‐for‐dental age than those of higher status. This was interpreted as likely reflecting poorer nutrition in the children of lower socioeconomic backgrounds. There was no patterning with respect to socioeconomic status in femur diaphyseal length or midshaft width. The results support the idea that, for skeletal populations, growth in cortical thickness may be a more sensitive indicator of adverse conditions in childhood than growth in bone length or width. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.     

Modulation of EGF binding and action by succinylated concanavalin A in fibroblast cell cultures

The role of the binding of succinylated concanavalin A to tissue culture cells in influencing epidermal growth factor (EGF)-mediated cell proliferation has been studied. Succinylated concanavalin A dramatically reduces the stimulation of 3T6 cells by EGF in Dulbecco's modified Eagle's medium (DME) containing insulin and vitamin B₁₂ as additional growth factors, but no serum. Furthermore, binding studies using ¹²⁵I-labeled EGF have shown that the binding of EGF to the cell surface is reduced upon addition of succinylated concanavalin A.     

HETEROCHRONY WITHIN SPECIES: CRANIOFACIAL GROWTH IN GIANT,STANDARD, AND DWARF RABBITS

Change in developmental timing is one source of heritable variation upon which selection can act. However, the amount of variation possible in ontogenetic trajectories is often unknown. We used three different-sized conspecific breeds of domestic rabbits to investigate the extent of variation in growth trajectories of craniofacial morphology. The growth and adult morphology of several structures (one soft tissue and 15 skeletal) were quantified and analyzed. We took two views of radiographs at close time intervals throughout ontogeny, from one week of age through adult size. Measurements from the radiographs were analyzed using a Gompertz growth model. Between-breed differences in model parameters were tested using one-way ANOVA. Few significant differences existed between the white and giant rabbits, but several differences were found between the white and dwarf breeds. Similarly, comparisons of adult morphology showed that white and giant rabbits are the same shape, while dwarf rabbits have shorter and broader snouts than white rabbits. The variation in size among breeds appeared to be due to differences in the length of time spent growing at rates near the maximum growth rate. While no one parameter of this model quantifies this pattern, differences in duration of maximum growth rate can be seen in the first derivative of the growth trajectory. Small changes in the model's parameters that measure rate and timing of growth have large morphological consequences, indicating that heterochronic changes are important sources of variation.     

A nonlinear structured population model of tumor growth with quiescence

A nonlinear structured cell population model of tumor growth is considered. The model distinguishes between two types of cells within the tumor: proliferating and quiescent. Within each class the behavior of individual cells depends on cell size, whereas the probabilities of becoming quiescent and returning to the proliferative cycle are in addition controlled by total tumor size. The asymptotic behavior of solutions of the full nonlinear model, as well as some linear special cases, is investigated using spectral theory of positive simigroup of operators. Supported in part by the National Science Foundation under Grant No. DMS-8722947     

Diurnal patterns of stem extension growth in peach (Prunus persica): Temperature and fluctuations in water status determine growth rate

Field measurements of stem extension growth rate in peach ( Prunus persica [L.] Batsch) exhibited a consistent diurnal pattern. Stem extension rate was lowest in the early morning and increased throughout the day. In the late afternoon, 2–3-fold increases in extension rate occurred and were sustained for 2 to 4 h. After this growth surge, rates precipitously declined and remained low during the night. The temperature response of stem growth rate at constant water potential was determined using potted trees in a dark growth chamber. Under such conditions, stem growth rate was strongly dependent on air temperature. In the field, the observed stem growth rate deviated from that predicted on the basis of temperature. These deviations were proportional to the rate of change in stem water potential. A model was constructed to predict diurnal patterns of stem extension rate using temperature and water potential data. The model was tested using data from undisturbed trees and from trees in which water potential was artificially manipulated. Growth patterns predicted by the model were in general agreement with observed rates.     

植物生长物质在水稻生长发育研究中的应用

概述了主要植物生长物质在水稻生长发育中的作用机理及应用情况,对使用植物生长物质存在的问题进行了讨论和展望．     

Characterization of a variety of neutralizing anti-heparin-binding epidermal growth factor-like growth factor monoclonal antibodies by different immunization methods

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family. The accumulated evidence on the tumor-progressing roles of HB-EGF has suggested that HB-EGF-targeted cancer therapy is expected to be promising. However, the generation of neutralizing anti-HB-EGF monoclonal antibodies (mAbs) has proved difficult. To overcome this difficulty, we performed a hybridoma approach using mice from different genetic backgrounds, as well as different types of HB-EGF immunogens. To increase the number of hybridoma clones to screen, we used an electrofusion system to generate hybridomas and a fluorometric microvolume assay technology to screen anti-HB-EGF mAbs. We succeeded in obtaining neutralizing anti-HB-EGF mAbs, primarily from BALB/c and CD1 mice, and these were classified into 7 epitope bins based on their competitive binding to the soluble form of HB-EGF (sHB-EGF). The mAbs showed several epitope bin-dependent characteristics, including neutralizing and binding activity to human sHB-EGF, cross-reactivity to mouse/rat sHB-EGF and binding activity to the precursor form of HB-EGF. The neutralizing activity was also validated in colony formation assays. Interestingly, we found that the populations of mAb bins and the production rates of the neutralizing mAbs were strikingly different by mouse strain and by immunogen type. We succeeded in generating a variety of neutralizing anti-HB-EGF mAbs, including potent sHB-EGF neutralizers that may have potential as therapeutic agents for treating HB-EGF-dependent cancers. Our results also suggest that immunization approaches using different mouse strains and immunogen types affect the biological activity of individual neutralizing antibodies.     

Characterization of a variety of neutralizing anti-heparin-binding epidermal growth factor-like growth factor monoclonal antibodies by different immunization methods

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family. The accumulated evidence on the tumor-progressing roles of HB-EGF has suggested that HB-EGF-targeted cancer therapy is expected to be promising. However, the generation of neutralizing anti-HB-EGF monoclonal antibodies (mAbs) has proved difficult. To overcome this difficulty, we performed a hybridoma approach using mice from different genetic backgrounds, as well as different types of HB-EGF immunogens. To increase the number of hybridoma clones to screen, we used an electrofusion system to generate hybridomas and a fluorometric microvolume assay technology to screen anti-HB-EGF mAbs. We succeeded in obtaining neutralizing anti-HB-EGF mAbs, primarily from BALB/c and CD1 mice, and these were classified into 7 epitope bins based on their competitive binding to the soluble form of HB-EGF (sHB-EGF). The mAbs showed several epitope bin-dependent characteristics, including neutralizing and binding activity to human sHB-EGF, cross-reactivity to mouse/rat sHB-EGF and binding activity to the precursor form of HB-EGF. The neutralizing activity was also validated in colony formation assays. Interestingly, we found that the populations of mAb bins and the production rates of the neutralizing mAbs were strikingly different by mouse strain and by immunogen type. We succeeded in generating a variety of neutralizing anti-HB-EGF mAbs, including potent sHB-EGF neutralizers that may have potential as therapeutic agents for treating HB-EGF-dependent cancers. Our results also suggest that immunization approaches using different mouse strains and immunogen types affect the biological activity of individual neutralizing antibodies.     

军标菌株生活史中各阶段生长发育时间的研究

为了更好地研究军标菌在其应用中的实验周期问题 ,采用插片培养法和载片培养法对军标中 5株实验菌的生活史中各阶段生长发育所需时间进行了研究。结果表明 ,5株菌的各时期生长发育所需时间有所不同。整个生活史最长的 4940min ,如AS 3 .42 5 4。最短的 3 888min ,如AS 3 .3 95 0。孢子萌发阶段所需时间也各不相同 ,最长的需 1 5 2 0min ,如AS 3 .3 885。最短的需 640min ,如AS 3 .3 95 0。这一研究为军标中霉菌试验周期 ,即 2 8d过长而且完全可缩短试验周期的观点 ,提供了有力的证据。     

SYNCHRONOUS GROWTH OF CHLAMYDOMONAS REINHARDTII (CHLOROPHYCEAE): A REVIEW OF OPTIMAL CONDITIONS1

Chlamydomonas reinhardtii Dangeard was synchronized at optimal growth conditions under a 12:4 LD regime at 35 C and 20,000 lx with serial dilution to a standard starting cell density of (1.4 ± 0.2) × 10⁶ cells/ml. Synchronous growth and division were characterized by measuring cell number, cell volume and size distribution, dry weight, protein, carbon, nitrogen, chlorophyll, carotenoids, nucleic acids, nuclear and cytoplasmic division during the vegetative life cycle. The main properties of the present system are: Exponential growth with high productivity, high degrees of synchrony and reproducibility during repeated life cycles. The degree of synchrony of this light-dark synchronization system was evaluated and compared with those described in the literature using probit analysis of the time course of DNA synthesis, nuclear and cytoplasmic division and sporulation (increase in cell number). The results showed that the degree of synchrony is highest for cells grown under optimal conditions.     

Neurite growth-inhibitory activity in the adult rat cerebral cortical gray matter

Axon growth-promoting and -inhibitory molecules are likely to work in concert to promote and guide axons in vivo. In adult mammals, inhibitory molecules associated with myelin in the white matter of the central nervous system (CNS) play an important role in the failure of long-distance axon regeneration. The presence of neurite growth-inhibitory molecules in the adult rat gray matter has not been extensively studied. In this article we describe work on the characterization of neurite growth-inhibitory activity in the adult rat cerebral cortical gray matter using various biochemical and cell culture approaches. We show using a neuronal cell line (NG108–-15 cells) that neurite growth-inhibitory activity is present in membrane preparations of the cortical gray matter. Purified gray matter membranes also induce growth cone collapse of cultured embryonic rat dorsal root ganglion neurons. The inhibitory activity in the membrane preparations is extractable with 3-[(3-cholamidoprophyl)-dimethylammonio]-1-propane-sulfonate, but does not appear to be depleted by various lectins. Western blots and enzyme treatments showed that the inhibitory effect of the gray-matter preparations is not likely to be mediated by myelin-associated inhibitors or chondroitin sulfate proteoglycans. However, tenascin was detected in these samples and may contribute to some of the inhibitory activity. Selective separation of the inhibitory molecules can be achieved by ion-exchange chromatography, which also suggests the presence of multiple inhibitors in cortical gray matter membranes. © 1997 John Wiley & Sons, Inc. J Neurobiol 32 : 671–683, 1997     

Production and reception of growth factors in placenta during physiological pregnancy and the pregnancy, complicated with gestosis

30 women with physiological pregnancy and 28 women with gestosis were examined. The content of epidermal growth factor (EGF), vascular-endothelial growth factor (VEGF) and their receptors were studied in the early chorion obtained after abortion and in the full-term placenta using the ELISA method. The process of normal gestation was characterized by the increase of the placental production both of the EGF and VEGF. During the pregnancy complicated with gestosis and miscarriage in the first trimester the content of EGF and its receptor was lower compared to the physiological values. For VEGF and its receptor opposite changes were found: the increase of quantity of the growth factor and the decrease of its receptor. In the case of gestosis and term of pregnancy the content of the both growth factors and their receptors was lower than in corresponding controls. The changes in production of the angiogenic growth factors and their receptors in the placenta may have the pathogenic importance in the development of gestosis.     

Single-Step Purification and Biological Activity of Human Nerve Growth Factor Produced from Insect Cells

Human nerve growth factor (NGF) was cloned and engineered for expression in a baculovirus-infected Spodoptera frugiperda (SF-9) insect cell system. Culture supernatants contained 2-3 mg/L of recombinant human NGF. The human NGF produced by this system was purified to apparent homogeneity with a single-step affinity chromatography procedure using a high-affinity monoclonal antibody originally raised against murine NGF. The purification procedure yielded 1-2 mg of pure, human NGF per liter of culture supernatant; i.e., approximately 60% recovery of the human NGF originally released into the culture medium. Although the gene transfected into the SF-9 cells coded for pro-NGF, the NGF recovered after purification was greater than 95% fully processed, mature protein. The KD for the affinity of the pure, recombinant human NGF for NGF receptor in PC12 membranes is 0.20 +/- 0.05 nM. Activation of neurite outgrowth in PC12 cells occurs with ED50 values of 85 +/- 20 pM and 9.6 +/- 1.5 pM for a 3-day primary response and a 1-day secondary response, respectively. The pure, recombinant human NGF also stimulates a significant increase in dopamine content of PC12 cells with an ED50 of 5.8 +/- 2.7 pM. These binding and biological activation properties are consistent with values observed using murine NGF purified from submaxillary glands.     

水动力条件下藻类动态模拟

藻类动态变化是其内部生理特征和外部驱动因素综合作用的结果。除了藻类自身生理因素及光、温度、营养盐等因素,水动力作用使底泥发生再悬浮所造成的营养盐的内源释放对藻类的影响也非常重要。1999年5月8日~6月24日在太湖湖泊生态系统研究站大型生态实验槽中进行了模拟水动力条件下的太湖藻类动态实验,并应用国外先进的PHREEQC软件从生物化学和生态动力学角度建立了藻类生态动力学模型。模型不仅考虑了氮循环及磷循环,还考虑了水动力条件引起的内源释放问题,根据2003年4月26~4月30日在河海大学环形水槽所做的底泥释放实验结果建立了水流和各形态氮磷营养盐释放的定量化关系。由于目前太湖的野外监测资料存在较明显的时空不一致性,模型参数率定的精度受到了较大影响。从室内模拟实验出发,通过对生态槽实验结果的模拟,确定和验证了模型的各参数值,计算结果显示模拟值能较好地拟合实验测量值,表明所建藻类生态动力学模型能较好地描述藻类及各种营养盐的动态变化,这对揭示藻类“水华”暴发机理有一定的意义。     

Examining the fungal and bacterial niche overlap using selective inhibitors in soil

It is important to know the contributions of bacteria and fungi to decomposition in connection with both the structure of the food web and the functioning of the ecosystem. However, the extent of the competition between these groups of organisms is largely unknown. The bacterial influence on fungal growth in a soil system was studied by applying three different bacterial inhibitors – bronopol, tylosin and oxytetracycline – in a series of increasing concentrations, and comparing the resulting bacterial and fungal growth rates measured using leucine and acetate-in-ergosterol incorporation, respectively. Direct measurements of growth showed that fungi increased after adding inhibitors; the level of increase in fungal growth corresponded to that of the decrease in bacterial growth, irrespective of the bacterial inhibitor used. Similar antagonistic effects of the bacteria on fungal growth were also found after adding the bacterial inhibitors together with additional substrate (alfalfa or straw plant material). The resulting responses in bacterial and fungal growth indirectly indicated that the negative interaction between fungi and bacteria was mostly attributable to exploitation competition. The results of this study also emphasize the increased sensitivity of using growth-related, instead of biomass-based, measurements when studying bacterial and fungal interactions in soil.     

Age-dependent quantitative trait loci affecting growth traits in Scottish Blackface sheep

To dissect age-dependent quantitative trait loci (QTL) associated with growth and to examine changes in QTL effects over time, the Gompertz growth model was fitted to longitudinal live weight data on 788 Scottish Blackface lambs from nine half-sib families. QTL were mapped for model parameters and weekly live weights and growth rates using microsatellite markers on chromosomes 1, 2, 3, 5, 14, 18, 20 and 21. QTL significance (using α = 0.05 chromosome-wide significance thresholds, unless otherwise stated) varied with age, and those for growth rate occurred earlier than equivalent QTL for live weight. A chromosome 20 QTL for growth rate was significant from 4 to 9 weeks (maximum significance at 6 weeks) and for maximum growth rate. For live weight, this QTL was significant from 8 to 16 weeks (maximum significance at 12 weeks). A nominally significant chromosome 14 QTL was detected for growth rates from birth to week 2 in the same families and location as an 8-week weight QTL. In addition, at the same position on chromosome 14, a QTL was significant for growth rate for 17–28 weeks (maximum significance at 24 weeks). A chromosome 3 QTL was significant for weights at early ages (birth to week 4) and a growth rate QTL on chromosome 18 was significant from 8 to 12 weeks. Fitting growth curves allowed the combination of information from multiple measurements into a few biologically meaningful variables, and the detection of growth QTL that were not observed from analyses of raw weight data. These QTL describe distinct parts of an animal's growth curve trajectory, possibly enabling manipulation of this trajectory.     

Mass production of human epidermal growth factor using fed-batch cultures of recombinant Escherichia coli

Fed-batch cultures of recombinant E. coli HB101 harboring expression plasmid pTRLBT1 or pTREBT1, with acetate concentration monitoring, are investigated to obtain high cell density and large amounts of human epidermal growth factor (hEGF). The expression plasmid pTRlBT1 contains a synthetic hEGF gene attached downstream of the N-terminal fragment of the trp L gene preceded by the trp promoter. The expression plasmid pTREBT1 contains the same coding sequence attached downstream of the N-terminal fragment of the trp E gene preceded by the trp promoter, trp L gene, and attenuator region. E. coli harboring pTREBT1 produces 0.56 mg/L hEGE and immediately degrades it. On the other hand E. coli harboring pTRLBT1 produces 6.8 mg/L hEGF and does not decompose it. Prominent inclusion bodies are observed in E. coli cells harboring pTRLBT1 using an election microscope. To Cultivate E. coli harboring pTRLBT1, a fed-batch culture system, divided into a cell growth step and an hEGF production step, is carried out. The cells grow smoothly without acetate-induced inhibition. Cell concentration and hEGF quantity reach the high values of 21 g/L and 60 mg/L, respectively.     

Statistical model of variable allometric growth: otolith growth in Micropogonias furnieri(Actinopterygii, Sciaenidae)

The main objective of this study was to develop a statistical model for accurate estimates of relative growth. The method was based on identifying patterns of the residuals obtained from the Huxley's allometric equation. Three different approaches were applied: (1) growth with variable proportionality and constant allometry coefficient, (2) growth with constant proportionality and variable allometry coefficient and (3) distinct growth phases in which proportionality and allometry coefficients remained constant. The proposed statistical models were applied to the relationship of the otolith size and fish size of whitemouth croaker Micropogonias furnieri . The best fit was obtained when using approach (3). A change in the growth parameters was associated with the attainment of sexual maturity.