Effects of Heavy Metal Stress on the Growth Curves of Two Sepcies of Bacteria

[Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were cultured under heavy metal stress including Cu2＋,Hg2＋,Pb2＋,Cd2＋ and Cr6＋ in different concentrations. Then the growth curves of the bacteria were determined to investigate the effects of exogenous heavy metals on the growth of the two kinds of bacteria. [Result] The proliferation of the two bacteria was inhibited at high concentrations of Hg2＋ and Cd2＋ respectively,and G＋ is more sensitive to them than G-; when the heavy metal concentration was 50 mg/L,the toxicity of the five kinds of heavy metals on the two bacteria was Hg2＋Cd2＋Cu2＋Cr6＋≈Pb2＋. [Conclusion] The research will provide a basis to explore the effects of heavy metal on environment and ecological system.

Study on Growth and Development Rules and Growth Curve Fitting of Minghua Black Minks

Growth curves of Minghua black minks at 0-180 days old were fitted and analyzed by using two growth models Logistic and Gompertz. The results showed that the growth curves of Minghua black minks could be fitted very well by Logistic model and Gompertz model （the degree of fitting FF≥0.99）, but Gompertz model was better at fitting and predicting their weight.

ASSESSMENT OF LOCAL INFLUENCE IN A GROWTH CURVE MODEL WITH RAO'S SIMPLE COVARIANCE STRUCTURE

The present paper deals with the problem of assessing the local influence in a growth curve model with Rao's simple covariance structure. Based on the likelihood displacement,the curvature measure is employed to evaluate the effects of some minor perturbations on the statistical inference, thus leading to the large curvature direction, which is the most critical diagnostic statistic in the context of the local influence analysis. As an application, the common covariance-weighted perturbation scheme is thoroughly considered.

ADMISSIBILITY OF LINEAR ESTIMATORS IN A GROWTH CURVE MODEL SUBJECT TO AN INCOMPLETE ELLIPSOIDAL RESTRICTION

This article considers the admissibility of the linear estimators for the regression coefficients in the growth curve model subject to an incomplete ellipsoidal restriction. The necessary and sufficient conditions for linear estimators to be admissible in classes of the homogeneous and non-homogeneous linear estimators, respectively, are obtained under the quadratic loss function. They are generalizations of some existing results in literature.

ADMISSIBILITY IN THE GENERAL GROWTH CURVE MODEL WITH RESPECT TO RESTRICTED PARAMETER SETS UNDER MATRIX LOSS FUNCTION

In this paper, we study the issue of admissibility in the growth curve model with respect to restricted parameter sets under matrix loss function. We obtain some neces- sary and sufficient conditions that the linear estimators of KBL are admissible in the class of homogeneous linear estimators and in the class of non-homogeneous linear estimators under the growth curve model with respect to restricted parameter sets, respectively.

Stimulated Growth of Aerobic Microbes Using Calcium Peroxide

With continuous and slow oxygen-release characteristic, calcium peroxide （CaO2） has been a new source of supplying oxygen for aerobic microbes in bioremediation of contaminated groundwater. Batch experiments were conducted to evaluate the oxygen-release rate of CaO2reacting with water, the regulation of high pH, as well as the growth of mixed aerobic microbes in the medium containing CaO2, The results show that the oxygen-release process of CaO2 comprises three phases. In the first phase, dissolved oxygen levels of water increased sharply, and average oxygen-release rates increased as the adding weight of CaO2 increased, However, the rates almost kept invariable in the latter phases and were approximately 0.48; and 0. 084 mg O2·h^-1, respectively. As the necessary components of medium, potassium dihydrogen phosphate （KH2PO4 ） and amrnoniurn sulphate （（NH4）2SO4） at a certain ratio could regulate pH caused by CaO2 from 12, 1 to the range of 6.5 -8.5, which is helpful for microbial growth, In addition, diauxic growth curve observed in the medium containing CaO2 suggested that the growth of mixed aerobic microbes could be stimulated by the addition of CaO2.

BAYESIAN LOCAL INFLUENCE ASSESSMENTS IN A GROWTH CURVE MODEL WITH GENERAL COVARIANCE STRUCTURE

The objective of this paper is to present a Bayesian approach based on Kullback- Leibler divergence for assessing local influence in a growth curve model with general co- variance structure. Under certain prior distribution assumption, the Kullback-Leibler di- vergence is used to measure the influence of some minor perturbation on the posterior distribution of unknown parameter. This leads to the diagnostic statistic for detecting which response is locally influential. As an application, the common covariance-weighted perturbation scheme is thoroughly considered.

Stochastic simulation of growth curves of Acidithiobacillus ferrooxidans

To reveal the low growth rate of Acidithiobacillus ferrooxidans, a stochastic growth model was proposed to analyze growth curves of these bacteria in a batch culture. An algorithm was applied to simulate the bacteria population during lag and exponential phase. The results show that the model moderately fits the experimental data. Further, the mean growth constant （K） of growth curves is obtained by fitting the logarithm of the simulating population data versus the generation numbers with the different initial population number （N0） and initial mean activity of population （A0）. When No is 300 and 700 respectively, the discrepancy of K value is only 0.91%, however, A0 is 0.34 and 0.38 respectively, the discrepancy of K value is 19.53%. It suggests that the effect of A0 on the lag phase exceeds No, though both parameters could shorten the lag phase by increasing their values.

Comparative Study on Analysis and Fitting of Pudong Chicken Growth Curve

The objective of this paper was to study the growth and development laws of Pudong chicken. The growth curve of Pudong chicken （cock and hen） from 0 to 20 weeks was analyzed and fitted with three models（Gompertz, Logistic and Bertalanffy）. It was concluded that the growth curves were appropriately fitted with three models, and fitness degree （R2）in growth data of Pudong chicken were all above 0.992. The Bertalanffy model was the most effective with the highest R2 for cock （R^2=0.995） and hen （R^2=0.999）, respectively. With further analysis of fitted parameters for Logis- tic model of cock, 0-3 weeks＇ fitted values were significantly greater than measured values and 4-8 weeks＇ fitted values were lower than measured values. Compared with Logistic model, the values calculated by Gompertz model and Bertalanffy model were more coincident with the practical measuring values. For hens, 0-3 weeks＇ fitted values of Logistic model were significantly greater than measured values and 0-2 weeks＇ fitted values of Gompertz model were slightly greater than measured values, while the values calculated by Bertalanffy model best matched the observed values from actual measure. The results showed that Bertalanffy model used to estimate the growth weight of Pudong chicken was the best while Logistic model was the worst. So the fitness and analysis of growth curves of Pudong chicken are valid, which may be adopted to predict growth and development laws of Pudong chicken and provide reliable data for precise feeding and breeding.

Establishment, Growth kinetics, and Susceptibility to AcMNPV of Heat Tolerant Lepidopteran Cell Lines

Lepidopteran heat-tolerant (ht) cell lines have been obtained with sf-9, sf-21 and several Bombyx cells. They have a distinct karyotype, membrane lipid composition, morphology and growth kinetics from the parental cell lines. In this paper, we report the development of ht cell lines from other insect species and examination of their growth characteristics and virus susceptibility. Adaptation of cell lines sf-9, BTI-TN-5B1-4 (High5) and BTI-TN-MG1 (MG1) to 33℃ and 35℃ was carried out by shifting the culture temperature between 28℃ and higher temperatures by a gradual stepwise increase in temperature. The process of adaption to a higher culture temperature was accomplished over a period of 2 months. The cell lines with the temperature adaption were designated as sf9-ht33, sf9-ht35, High5-ht33, High5-ht35, MG1-ht33, MG1-ht35. These cell lines have been subcultured over 70 passages. Adaption to high temperatures was confirmed by a constant population doubling time with individual cell lines. The population doubling time of heat adapted cell lines were 1-4 h less than these of parental cell lines. Cell shapes did not show obvious change, however, the cell size of sf9-ht cells was enlarged and those of High5 and MG1 ht cells were reduced after heat adaption. When the cell lines were infected with Autographa californica nuclear polyhedrosis virus (AcMNPV) at 28℃, 33℃, 35℃ and 37℃, production of budded virus and occlusion bodies in each cell line was optimum at its own adapted temperature.

Growth Curves Analysis of Five Meat Rabbit Breeds

The growth curves of five meat rabbit breeds are fitted in form of Gompertz model.The results are shown as follows:the goodness of fit is higher than 99 50%;considering the body weight at one hundred day?the maximum weight(A)?the instantaneous relative growth rate(K)?the turning weight(W )?the turning age (t )?the early average daily gain (KW ) selection,the Checkered Giant(GG) and the New Zealand White (NN) are better than other meat breeds,the slauthter age should be at the age of 90 day.

The Influence of Different Single Radiation Dose on Delayed Growth of Transplanted Tumor in Athymic Mouse

OBJECTIVE To reveal the biological effects and effective dosage in radiotherapy model which applies high single-dose irradiation by animal experiment. METHODS We inoculated subcutaneouly human pancreatic carcinoma cell line （MIA PaCa-2） in the lateral of the right lower extremity of the athymic mouse to grow transplantation tumor. While the median diameter of transplantation tumor reached 10 mm approximately, the animals were randomly divided into 7 groups （6 animals per group） and irradiation by different dose in one fixed with consciousness for fraction （0, 2, 5, 10, 17, 25, 35 Gy）. All were kept on to be bred for observation of the change in gross tumor volume, calculation of delayed growth time and delayed growth curve. RESULTS With increased dose per fraction, cutaneous reaction on the neoplasma surface of the animal, which was mainly moist yellow effusion was more and more severe. When dosage is less than 10 Gy, all animals showed similar effects, that＇s the delayed tumor growth was not obvious. Tumors receiving more than 10 Gy in one fraction showed very good biological effect and the delayed tumor growth was obviously related to dosage. The difference in delayed tumor growth between the 2 groups was statistically significant. The delayed tumor growth time in 10, 17, 25 Gy group was respectively 3 weeks, 6 weeks and more. CONCLUSION The biological effect of the model which applies high single-dose irradiation （more than 10 Gy in one fraction） was very good. The effect of delayed tumor growth was obviously related to the dosage after transplantation tumor was radiated. Because of its higher dose per fraction and biological effects, the model of high single-dose irradiation can get better clinical effects.

Growth Modeling of Charolais and Serrana Soriana Native Spanish Beef Cattle

The alternative productions, increasingly importance, are based on the rational utilization of the resources, on agreement with the environment and the use of autochthonous breeds that many cases are found in danger of disappearance, due to the tact that their suckling is not economically profitable. A way of predicting and knowing the growth of the animals is using mathematical models. This work presented the results of the estimate of the growth according to the Gompertz-Laird model of males of the atttochthonous breed Serrana Soriana and Charolais. The weight to the birth of the breed calfs Charolais （45.14 kg）, was superior to those of Serrana Soriana （40.13 kg）, and presented a greater relative growth （9.9%） before the inflection point of the growth curve： furthermore it ~as also superior to the maximum decline relative after this point （6%）, Serrana Soriana reached 7 days after the maximum growth point but with a smaller weight （315.05 kg vs 384.76 kg）. It was calculated a weight to the maturity of 1 ,（176.91） kg for Charolais and 856.40 kg for Serrana Soriana.

Admissibility of Linear Estimators in the Growth Curve Model with Respect to Inequality Restriction

For the growth curve model with respect to inequality restriction： Y = XBZ ＋ε,ε（0, σ2V I）, trNB ≥0, this paper gives some necessary and sufficient conditions for the linear estimator of KBL to be admissible in the class of homogeneous linear estimators LH and nonhomogeneous linear estimators LI, respectively, under the quadratic loss function tr（d（Y） - KBL）＇（d（Y） - KBL）.

AIC-Based Selection of Growth Models: The Case of Piglets from Organic Farming

The selection and comparison of different growth models for describing weight gain of piglets raised in organic farming is investigated by using the Akaike’s Information Criterion (AIC). In total, 49,699 data points of 5188 piglets recorded between 2007 and 2013 were considered. From the day of birth, up to 40 days (i.e. until weaning) the model of von Bertalanffy was favored by the AIC. This model is with 60.32% more likely to truly reflect reality than any other of the analyzed models. Up to 105 days, the two-linear model was favored by the AIC (probability 99.75%). The intersection point of the two-linear model was calculated by 53.8 days, which fitted well to the actual change in the food situations.

Study on Antibacterial Activity of 2-Methyl-3-(methylthio)Pyrazine Against Three Strains of Spoilage Bacteria

Previous studies have shown that glycine and proline are pharmacophores that display antibacterial activity.In the present study,glycine and proline were derivated to diketopiperazine compounds by chemical synthesis method,and their antibacterial activities were evaluated by three strains of spoilage bacteria,Escherichia coli,Pseudomonas aeruginosa and Shewanella putrefaciens,and the relationship of their antibacterial activities and structures was also investigated.Uv-vis spectrophotometry was used to determine the growth curves of three kinds of active indicator bacteria.Minimum inhibitory concentration(MIC)was determined by micro broth dilution method.The results showed that 2-methyl-3-(methylthio)pyrazine had significant antibacterial activity against three strains of the bacteria,and its MIC was 1.25%.It indicates 2-methyl-3-(methylthio)pyrazine has the potential to be developed as a kind of preservative in future.

Callus Induction and Cell Suspension Culture of Eggplant(Solanum melongena L.)

[Objective] The aim of this article is to establish a cell suspension culture system for eggplant. [Method] Using orthogonal design, appropriate media were screened for callus induction, subculture and cell suspension culture. [Result] The appropriate medium for callus induction was MS supplemented with 0.2 mg/L 6-BA and 0.2 mg/L NAA; the appropriate subculture medium was MS supplemented with0.2 mg/L 6-BA, 0.2 mg/L NAA, and 0.1 mg/L KT; the suitable medium for cell suspension culture was liquid MS medium supplemented with 0.4 mg/L NAA and 0.2mg/L. Cell growth curve was similar to ＂S＂ shape in the above suspension medium.The cell growth included four phases, the initial phase（1-3 d）, the logarithmic phase（3-7 d）, the steady phase（7-8 d）, and the decline phase（8-11 d）. With the increasing culture time, the number of suspension cells increased, and it reached the maximum value at the 7thd, about 3.8 ×105cells/ml. Then the number of cells began to decline rapidly. The cell vigor was the highest at the initial phase. Suspension cells grew best in the liquid MS medium supplemented with NAA（0.4 mg/L）and 6-BA（0.2 mg/L）. The mitotic index reached the maximum, about 4.1% in the above medium, which suggested that this medium was suitable for cell suspension culture of eggplant. [Conclusion] Cell suspension culture system of eggplant provides a significant method for eggplant biotechnology. Genetic transformation and mutants screening can be carried out with this system.

Variation Law of Pericarp Tenderness of Super Sweet Corn Kernel

To investigate the variation law of pericarp tenderness in growth progress of super sweet corn kernel, the values of pericarp tenderness of 10 super sweet corn inbreeds were measured during kernel growth, and the variations under differ- ent conditions were analyzed. The results showed that there existed gradient differ- ences in pericarp tenderness among the 10 materials, of which PE10 had the best pericarp tenderness, T105 took medial place, and $33205 performed worst in peri- carp tenderness. Pericarp tenderness values of these 3 inbreeds increased curvedly from 12 to 24 days after pollination, in the spring （Wuhan, Hubei） and winter （Ling- shui, Hainan） of 2014. Moreover, the average pericarp tenderness at different time points presented the same decreasing order of $33205, T105, PE10, which was not altered by enviroment. With the growth of kernel, for one material, the difference of pericarp tenderness under different environments presented a law of increment, re- duction, uniformity. As for optimum-picking time, there was four days difference be- tween the spring in Wuhan and winter in Lingshui. However, there was no obvious difference in pericarp tenderness on the optimum picking time, which indicated that growing environment could affect the variation ratio of pericarp tenderness, but it still depended on the nature of materials.

A promising resilience parameter for breeding:the use of weight and feed trajectories in growing pigs

Background Increasing resilience is a priority in modern pig breeding.Recent research shows that general resilience can be quantified via variability in longitudinal data.The collection of such longitudinal data on weight,feed intake and feeding behaviour in pigs has been facilitated by the development of technologies such as automated feeding stations.The goal of this study was to investigate resilience traits,which were estimated as deviations from longitudinal weight,feed intake and feeding behaviour data during the finishing phase.A dataset with 324,207 records between the age of 95 and 155 days on 5,939 Pietrain pigs with known pedigree and genomic information was used.We provided guidelines for a rigid quality control of longitudinal body weight data,as we found that outliers can significantly affect results.Gompertz growth curve analysis,linear modelling and trajectory analyses were used for quantifying resilience traits.Results To our knowledge,this is the first study comparing resilience traits from longitudinal body weight,feed intake and feeding behaviour data in pigs.We demonstrated that the resilience traits are lowly to moderately heritable for deviations in body weight(h2=2.9%–20.2%),in feed intake(9.4%–23.3%)and in feeding behaviour(16.2%–28.3%).Additionally,these traits have good predictive abilities in cross-validation analyses.Deviations in individual body weight and feed intake trajectories are highly correlated(rg=0.78)with low to moderate favourable genetic correlations with feed conversion ratio(rg=0.39–0.49).Lastly,we showed that some resilience traits,such as the natural logarithm of variances of observed versus predicted body weights(lnvarweight),are more robust to lower observation frequencies and are repeatable over three different time periods of the finishing phase.Conclusions Our results will help future studies investigating resilience traits and resilience-related traits.Moreover,our study provides first results on standardization of quality control and efficient data sampling from automated feeding station data.Our findings will be valuable for breeding organizations as they offer evidence that pigs’general resilience can be selected on with good accuracy.Moreover,this methodology might be extended to other species to quantify resilience based on longitudinal data.

Nitraria sibirica cell suspension culture:establishment,characterization and application

Nitraria sibirica Pall. is a shrub that grows in saline-alkali soil and has traditional medicinal value and potential commercial value. The objectives of this study include induction and multiplication of callus, establishment of a suspension cell line, and isolation of protoplasts from cell suspensions. Murashige and Skoog (MS) medium was used for callus induction from mature seeds of N. sibirica. Seed-derived calluses were further multiplied on MS medium augmented with 0.5 mg L-1 6-benzylaminopurine (6-BA) and 1.0 mg L-1 2,4-dichlorophenoxy (2,4-D) acetic acid. Suspension cultures of N. sibirica were initiated by transferring friable calli to the same liquid multiplication medium. Characterization of the suspension culture was assessed based on fresh mass, dry mass, cell viability and pH value of the culture. A typical growth curve was observed after inoculating 1.5 g of callus in 40 mL liquid medium, including a lag phase, an exponential growth phase, a stationary phase, and a negative acceleration phase. The effect of factors such as pre-plasmolysis, enzyme combination, enzymolysis time and mannitol concentration, on the isolation of cell-derived protoplasts were evaluated to determine the usefulness of suspension cultures. The maximum yield (9.79 x 10(6) cells/g) and highest viability (79.97%) of protoplast were reached when approximately 1 g of cell suspension (cultured for 6 days) was inoculated for 12 h in cell and protoplast washing solution made of 0.8 mol L-1 mannitol mixture solution, cellulose onozuka R-10 2% (w/v), hemicellulose 0.2%, macerozyme R-10 1%, and pectolyase Y-23 0.5%. Protoplast yield was significantly influenced by pre-plasmolysis and cellulose onozuka R-10 (P < 0.05).