Implications of the pH and temperature of diluted, cooled boar semen on fresh and frozen-thawed sperm motility characteristics

Boar semen is typically collected, diluted and cooled for AI use over numerous days, or frozen immediately after shipping to capable laboratories. The storage temperature and pH of the diluted, cooled boar semen could influence the fertility of boar sperm. Therefore, the purpose of this study was to determine the effects of pH and storage temperature on fresh and frozen-thawed boar sperm motility end points. Semen samples (n = 199) were collected, diluted, cooled and shipped overnight to the National Animal Germplasm Program laboratory for freezing and analysis from four boar stud facilities. The temperature, pH and motility characteristics, determined using computer automated semen analysis, were measured at arrival. Samples were then cryopreserved and post-thaw motility determined. The commercial stud was a significant source of variation for mean semen temperature and pH, as well as total and progressive motility, and numerous other sperm motility characteristics. Based on multiple regression analysis, pH was not a significant source of variation for fresh or frozen-thawed boar sperm motility end points. However, significant models were derived which demonstrated that storage temperature, boar, and the commercial stud influenced sperm motility end points and the potential success for surviving cryopreservation. We inferred that maintaining cooled boar semen at approximately 16 °C during storage will result in higher fresh and frozen-thawed boar sperm quality, which should result in greater fertility.     

The influence of pH and temperature on ethylene production by mycorrhizal fungi of pine

The production of ethylene by six mycorrhizal fungi of pine (Pinus sylvestris L.) grown in media with and without methionine at temperatures of 20° C and 26° C and at pH 4.0, 6.0 or 7.0 was studied. The fungi produced more ethylene at 26° C than at 20° C, and more ethylene in media containing methionine than in media without this precursor. The fungi studied synthesized the highest amounts of ethylene at 26° C and pH 6.O.     

Effects of pH and temperature on myocardial calcium-activation in Pterygoplichthys (catfish)

Fish are chronically exposed to a wide range of temperatures and acidic environments. Fish hearts have to therefore adapt to these changes in order to maintain contractility. Myofibrillar responsiveness to Ca²⁺ is exquisitely sensitive to both temperature and pH in mammalian myocardium. To evaluate myofilament calcium-activation, we chemically skinned ventricular myocardium from catfish (Pterygoplichthys). A decrease in pH from 7.5 to 6.8, irrespective of temperature change, shifted the calcium-force curve towards higher calcium concentrations without affecting maximal Ca²⁺-activated force. The contractile elements are therefore sensitive to changes in pH. In intact muscle preparations the active twitch force was decreased with increasing temperature (10–22 °C). However, the sensitivity of the myofilaments to Ca²⁺ was independent of temperature. These data suggest a possible role of the sarcoplasmic reticulum (SR) in mediating the effects of temperature. The response of intact muscle preparations to changes in temperature is therefore not likely due to temperature-dependent changes in myofilament calcium responsiveness. Accepted: 11 May 1998     

The role of visible faecal material as a vehicle for generic Escherichia coli,coliform, and other enterobacteria contaminating poultry carcasses during slaughtering

AIMS: A comparison of Enterobacteriaceae, coliform and Escherichia coli counts in chicken carcasses with and without visible faecal contamination was conducted to evaluate the role of contamination as a vehicle for generic E. coli, coliform and other enterobacteria contaminating broiler chicken carcasses when processed under routine commercial operations. METHODS AND RESULTS: Samples were removed from the processing line immediately after evisceration, inside-outside shower and chilling for microbiological analysis. After evisceration, mean counts were significantly different only for E. coli (P < or = 0.05) in chicken carcasses with and without visible faecal contamination. While the spray wash practice was not efficient enough for complete removal of the visible contamination from carcasses, leading to microbiological reduction percentages lower than expected, 25 ppm chlorinated water chilling did reduce the contamination level considerably in all samples. CONCLUSIONS: Carcasses with and without visible faecal contamination harboured E. coli and other potentially hazardous enterobacteria. E. coli was the predominant strain isolated in all samples, Enterobacter cloacae being next most frequent. SIGNIFICANCE AND IMPACT OF THE STUDY: The zero tolerance of visible faecal contamination requirement alone is not sufficient to assure safety and to improve the microbial quality of carcasses.     

光照、温度和pH对雨生红球藻光合特性的影响

采用测定光合放氧速率和荧光动力学的方法,研究分析了光照强度、温度和pH对雨生红球藻Haematococcus pluvialis CG-11绿色游动细胞阶段光合作用特性的影响。结果表明,H. pluvialis CG-11光合作用的饱和光强为109.1 μmol/m2·s,最大光合放氧速率为75.9 μmol O2/mg Chla·h;适宜的生长温度范围在25－30℃之间,温度在25℃时光合速率最大;pH在7.5－8.0范围内,光合效率较高,在pH为7.5时放氧速率最大,为75.5 μmol O2/mg Chla·h。在实验pH条件下,H. pluvialis CG-11叶绿素荧光动力学参数呈现出相似的趋势,在6.0－7.5范围内,Fv/ Fm、Fv/ F0、ΦPSⅡ和ETR值随pH升高而增大,pH为7.5时达到最大值,pH超过7.5时,Fv/ Fm和Fv/ F0值明显下降,而ΦPSⅡ和ETR的下降趋势不明显。     

The effects of pH and temperature on the kinetic properties of skeletal muscle lactate dehydrogenase from anuran amphibians

Summary Muscle LDH activities were measured in two anuran amphibians with different behaviour and ecology, Rana perezi and Bufo calamita. Both pyruvate reduction and lactate oxidation were measured at temperatures of 15, 20 and 30°C, and at pH 7.0, 7.4, and 8.0. Pyruvate and lactate muscle concentrations were determined in individuals at rest and after exercise. R. perezi muscle used anaerobic glycolysis during 3 min of exhaustive exercise, with rising pyruvate and lactate concentrations. Enforced walking for 30 min caused high variability in lactate concentration in B. calamita muscle. Temperature and pH changes affected apparent Km values for pyruvate. When these factors varied simultaneously, enzyme affinity tended not to change. Thus, the thermodynamic effect on pyruvate reduction activity is high, especially at physiological substrate concentrations. In contrast, lactate oxidation activity tended to stabilize when temperature and pH varied jointly. Inhibition by substrate, pyruvate or lactate, seemed to have no importance in vivo.During exercise there was a rise in pyruvate concentration, and a probable decrease in pH, which increased pyruvate reduction reaction and decreased lactate oxidation, contributing to lactate accumulation in Rana perezi muscle. B. calamita muscle did not show pyruvate increase after exercise and its LDH was less dependent on pH at physiological concentrations. Pyruvate reduction rate did not therefore increase. R. perezi muscle enzyme had features of anaerobic LDH while B. calamita LDH muscle was more similar to mammalian heart enzyme, with differences in accordance with the different behaviour of these anurans.Abbreviations LDH lactate dehydrogenase     

温度、相对湿度和pH对蜜蜂球囊菌孢子萌发的影响

研究了温度、相对湿度和pH对蜜蜂球囊菌(Ascosphaeraapis)孢子萌发3个阶段(活化、膨大、产生萌发管)的影响．结果表明,孢子活化和膨大在15～40和(25～40)±0．5℃范围内受温度的影响不明显(P＞0．05);萌发管仅发生在25～37±0．5℃,最适温度位于(31～35)±0．5℃．相对湿度越大,越有利于孢子萌发,而相对湿度低于80％对孢子萌发极为不利．孢子萌发的3个阶段在pH为5～7．8时几乎不受pH变化的影响,而在pH值较低影响很大．可见,A．apis是一种高度专一的蜜蜂幼虫病原体．     

Estimates of Frankia growth under various pH and temperature regimes

Summary The growth of Frankia isolates was monitored by dry weight, total protein and total ATP measurements under different temperature and pH regimes. Significant correlations (P<0.01) were found among all growth measures which meant that similar general conclusions were reached irrespective of the study method involved. The assessment of protein was the method of choice for regular assessments of Frankia growth due to its facility and relatively high sensitivity. The optimum temperature for growth of isolate LDAgp1 and AvcI1 was about 30°C while for CpI1 it lay between 30° and 35°C. No growth was observed at 40°C but some growth was observed at 10°C with isolate CpI1 and LDAgp1 over an extended growth period of 39 days. The range of pH favouring growth lay between 6 and 8. The optimum for LDAgp1 lay between 6.5 and 7, that for AvcI1 and CpI1 is close to 6.5. The pH response was medium dependent. Increases in biomass were observed for some isolates at 4.6 and above 8.0 on some media.     

The combined effect of temperature and pH on embryonic development of obscure puffer Takifugu obscurus and its ecological implications

Rising temperature and decreasing pH caused by climate change may affect the development of fish. The objective of this study was to determine the combined effects of temperature (19, 22, 25, 28 °C) and pH (5, 6, 7, 8) on incubation time, total hatch rate, abnormal rate, and viability of newly hatched larvae 24 h post-hatch of obscure puffer Takifugu obscurus fertilized eggs. The results showed that incubation time was significantly shortened with increase in temperature and delayed at low pH. Significant interaction was detected between temperature and pH on incubation time. Both temperature and pH significantly affected the total hatch rate, abnormal rate, and the viability of newly hatched larvae, but no significant interaction was detected. Such results indicated that fluctuations in temperature and decreasing pH in waters during the spawning season of this anadromous species may have substantially negative impacts on its population recruitment and persistence.     

Sperm motility in fishes. I. Effects of temperature and pH: a review

Sperm motility is a key factor in allowing us to determine semen quality and fertilizing capacity. Motility in semen is mainly controlled by K+ in salmonids, and probably also in sturgeons, and by osmotic pressure in other freshwater and seawater fish species, but other factors, such as concentration of surrounding metabolites and ions (Ca2+, Mg2+, etc.), pH and temperature also influence motility characteristics. In the present study, we have mainly reviewed and summarized the effects of temperature and pH on the motility of spermatozoa in three fish species: salmonids, cyprinids and sturgeons. Data in the literature show that motility, fertilizing ability and velocity of spermatozoa, as well as the duration of the motility period, depend on the temperature of the assay medium and also of that of the brood fish holding tank. In contrast, the pH of the swimming medium, and thus the intracellular pH of spermatozoa, has less influence on sperm motility parameters in cyprinids, salmonids and sturgeons.     

The prevalence of Salmonella spp. in bovine faecal,rumen and carcass samples at a commercial abattoir

AIMS: To determine the prevalence, serotype and antibiotic resistance profile of Salmonella isolates in cattle and on carcasses at a commercial Irish abattoir. METHODS AND RESULTS: Faecal, rumen and carcass samples were collected from a beef abattoir over a 12-month period and examined for the presence of Salmonella spp. Isolates were serotyped, phage typed (when serotype was found to be S. Typhimurium) and tested for susceptibility to a panel of antibiotics. Salmonella was isolated from 2% of faecal, 2% of rumen and 7.6% of carcass samples. Salmonella was most frequently isolated from samples taken during the period August to October. S. Dublin was isolated from 72% of positive samples. S. Agona and S. Typhimurium definitive type (DT)104 were each isolated from 14% of positive samples. All S. Typhimurium DT104 isolates were resistant to ampicillin, chloramphenicol, streptomycin, sulphafurazole and tetracycline (ACSSuT). On occasion, from a single animal, the same serotype was isolated from more than one sample (i.e. faeces and rumen; faeces and carcass; rumen and carcass; faeces, rumen and carcass). CONCLUSIONS: Salmonella is present in cattle at slaughter and on beef carcasses at an Irish abattoir, with a higher frequency of occurrence during the period August to October. Most isolates from the study are not commonly associated with human clinical infection, with the exception of S. Typhimurium DT104 (R-type ACSSuT). SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides epidemiological data that is necessary for the understanding of beef as a source of human Salmonella infection.     

温度、pH对圆背角无齿蚌滤水率的影响

圆背角无齿蚌（Anodonta woodianapa cifica）是我国重要的经济贝类,广泛分布于各大水系;营底栖生活,通过滤水作用摄食水中的浮游生物和有机碎屑;其肉多壳薄,是优良的动物饵料;在水体生态系统的物质循环和能量流动及水质净化中起着十分重要的作用。     

Effect of substrate concentration,inorganic nitrogen,O2 concentration,temperature and pH on dehydrogenase activity in soil

Summary Dehydrogenase activity was measured in a sandy loam soil under a variety of incubation conditions using the reduction of 2-(p-iodophenyl-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to iodonitrotetrazolium formazan (INT-formazan). There was a high positive correlation between dehydrogenase activity and substrate concentration, incubation temperature, and soil pH. Dehydrogenase activity also displayed a high negative correlation with O₂ concentrations. Ammonium sulfate at concentrations from 40 to 120 g/g soil had no significant effect on dehydrogenase activity. However, at concentrations of 160 and 200 g/g, dehydrogenase activity was significantly reduced. Potassium nitrate at concentrations ranging from 40 to 200 g/g had no significant effect on soil dehydrogenase activity, whereas sodium nitrite significantly inhibited activity at concentrations of 120 and 160 g/g soil.     

Interactions of temperature and pH on the regulatory properties of pyruvate kinase from organs of a marine mollusc

The effects of low temperature assay (5 °C) on the properties of the aerobic (low phosphate) vs. anoxic (high phosphate) forms of pyruvate kinase (PK) from foot muscle and gill of the whelk Busycon canaliculatum (L.) were assessed at two pH values, pH 7.00 and 7.25, and compared to control conditions of 20 °C and pH 7.00 (all assayed in imidazole buffer). When pH was held constant at 7.00, the decrease in assay temperature to 5 °C had large effects on the measured kinetic parameters of all PK forms, as compared to 20 °C and pH 7.00. However, when assay pH was allowed to rise, from 7.00 to 7.25, with the temperature decrease to 5 °C there were fewer alterations of kinetic parameters and quantitatively smaller changes to enzyme properties. It appears, then, that when pH rises with decreasing temperature following alphastat predictions, kinetic properties of PK are largely conserved. Low temperature, at either pH value, had several significant effects on PK properties. For example, low temperature raised the S_0.5 for phosphoenolpyruvate of PK-anoxic from gill by 3–6 fold and decreased the I₅₀ Mg · ATP for PK-anoxic from foot by the same amount. Arrhenius plots of PK activity for the gill PK forms showed a distinct break at 10 °C; > 10 °C Q₁₀ was 2.5 whereas < 10 °C Q₁₀ was 8.4. Temperature-dependent changes in all cases affected enzyme properties in a manner that would restrict enzyme function at low temperature.     

pH Condition in temperature shift cultivation enhances cell longevity and specific hMab productivity in CHO culture

Controlling cell proliferation during cell culturing is an effective way to improve the production yield in mammalian cell culture. We examined the effect of temperature shifts (TS) under pH control conditions in Chinese hamster ovary cells. When we shifted the culture temperature from 37 °C to 31 °C before a stationary phase at pH 6.8 (TS/pH 6.8), cell viability remained high, and the final human monoclonal antibody (hMab) concentration increased to 2.3 times that in the culture remaining at 37 °C. However, there were no significant effects on the cell viability or production yield with the same TS at pH 7.0 (TS/pH 7.0). The average specific hMab productivity and mRNA level of TS/pH 7.0 were the same as that of TS/pH 6.8. The control of cell growth by the TS or the addition of rapamycin was effective in the maintenance of cell viability, but there was no significant increase of the average specific hMab productivity in the culture where cell proliferation was controlled with rapamycin. The hMab mRNA concentration decreased to 55%–65% at a 37 °C culture with the addition of actinomycin D. In contrast, actinomycin D did not affect the mRNA level in the TS culture. This result suggested that the increase in the mRNA level in the TS condition was caused by an increase in mRNA stability. In this study, we show that TS can produce two unrelated effects: a prolongation of cell longevity and an improvement in mRNA stability.     

温度光照pH对雨生血球藻CG-11绿色营养细胞生长的影响

采用BBM培养基,以雨生血球藻Haematococcus pluvialis CG-11为研究材料,进行环境因子对雨生血球藻绿色营养细胞生长影响的实验。温度梯度为16℃、20℃、24℃、28℃;光照梯度为30μmoL photons m^-2·s^-1、60μmoL photons m^-2·s^-1、90μmoL photons m^-2·s^-1、120μmoL photons m^-2·s^-1。初始pH值为6.0、7.0、8.0、9.0,进行单因子试验,测定各组的藻密度及色素含量。结果显示,雨生血球藻H.pluvialis CG-11生长的最适温度范围20～24℃,光照90μmol photons m^-2·s^-1,初始pH8.0。     

Further studies on bovine serum amylase - the effect of gel buffer pH

This paper describes the effect of gel buffer pH on the resolution of bovine serum amylase (Amylase I) isozymes in starch gel and the consequences for the understanding of the genetics of this locus. The two main findings are: (1) the existence of a satellite isozyme E to isozyme C which at pH 7.3 has the same mobility as the B isozyme but which at pH 8.0 migrates slower than B, and (2) the finding of three alleles AmI A, AmI B and AmI C in British cattle populations previously reported as having only AmI B and AmI C .     

温度、pH 对剑状矛蚌滤水率的影响

测定了剑状矛蚌(Lanceolaria gladiola)在不同温度和不同pH条件下的滤水率.结果表明,在不同温度(10～28℃)条件下,剑状矛蚌的滤水率均随温度升高而上升,达到最大值后呈下降趋势,其中滤水率最大值出现在24℃时,大、中、小个体组剑状矛蚌滤水率最大值分别为0.826 L/h、0.768 L/h和0.65...     

温度、水分和施氮量对温室土壤pH及电导率的耦合作用

选取5年棚龄温室土壤样品进行培养试验,研究温度(T)、水分(W)、施氮量(N)及其耦合效应对温室土壤pH及电导率（EC）的影响.结果表明：随着培养时间延长,温室土壤pH逐渐下降,下降速率可用一级反应模型进行定量描述,其速率常数受各因素的影响表现为N>W>W×N>T×W. EC在培养的第1周内快速上升到最大值后略有下降,并在培养后期逐渐趋于稳态值（EC_sty）,EC_sty受N、W、T×W、T及W×N的影响,其中N、W、T×W和T的影响达到极显著水平,W×N的影响达到显著水平;通过减小施氮量及适当亏水灌溉可有效延缓温室土壤酸化和EC升高.建立了pH下降速率常数及EC_sty回归模型,可对不同环境及水肥条件下土壤酸化及EC变化进行预测.     

Modelling frost resistance of Scots pine seedlings using temperature,daylength and pH of cell effusate

The annual course of frost resistance (LT₅₀) and the pH of the cell effusate in needles of two-year-old Scots pine seedlings were monitored in a field experiment in Oulu, Northern Finland (65° N, 25° E) during 1995. The aim of the work was to to develop model to predict the annual variation in frost resistance by pH of the cell effusate and meteorological data. The seedlings were covered with a fibre cloth shelter which transmitted sufficient light for them to experience the photoperiod, but prevented the accumulation of snow over them. The shelter above the seedlings was removed at the beginning of May and erected again at the end of September. The seedlings were watered only for the time when the shelter was removed, and received fertilizer only during the previous summer (1994).Frost resistance was only -5° C during the growing season but more than -100° C during the winter rest period. It was about -10° C at the end of August, increased to -55° C in the next three weeks, and reached -100° C at the beginning of October. The pH of the cell effusate was lowest during the growing season and highest in winter, the difference being about one and half pH unit. Needles exposed to -196° C showed pH from 4.0 in summer to 5.5 in winter, while pH of the non-frozen needles varied from 5.0 to 6.5, respectively. Seasonal variation in frost resistance was explained by a regression model well (R² = 0.9) when day length, minimum air temperature and pH were entered as variables.