Effects of long-term storage on the stability of OpMNPV DNA contained in TM Biocontrol-1

Orgyia pseudotsugata multicapsid nucleopolyhedrovirus (OpMNPV) DNA was extracted from samples representing 10 lots of TM Biocontrol-1 stored at -10 degrees C for 5-15 years and digested with the restriction enzymes BglII, PstI, and SalI. DNA from the OpMNPV virus strain (MEM-75-STANDARD) used to produce the TM Biocontrol-1 lots was also extracted and digested. No restriction fragment length polymorphisms were observed in any of the samples and there was no evidence of DNA degradation. This indicates that long-term cold storage of TM Biocontrol-1 had no adverse effect on the quality of the OpMNPV DNA. In addition to the expected >23 kb OpMNPV DNA, extracts from lots 4a, 5b, and 6 contained 10 additional nucleic acid segments, ranging in size from 0.9 to 4.2 kb. The electrophoretic profile of these segments was characteristic of O. pseudotsugata cypovirus (OpCPV). RNase A/DNase I treatment showed that the nucleic acid contaminants were composed of RNA, suggesting that lots 4a, 5b, and 6 contained OpCPV as well as OpMNPV. Bioassay results have shown that there is a decrease in efficacy of stored TM-biocontrol-1, but this did not appear to be directly correlated with the length of time in storage.     

Production of polyhedrin monoclonal antibodies for distinguishing two Orgyia pseudotsugata baculoviruses.

Monoclonal antibodies were produced to polyhedrins from Orgyia pseudotsugata multicapsid nuclear polyhedrosis virus (OpMNPV) and single-capsid nuclear polyhedrosis virus (OpSNPV). Although the polyhedrins are closely related, antibodies were selected which allowed differentiation between the two viruses. In an indirect enzyme-linked immunosorbent assay, purified OpMNPV and OpSNPV polyhedrins could be detected by specific monoclonal antibodies at concentrations as low as 2 and 5 ng/ml, respectively. The antibodies were also capable of identifying their homologous polyhedrin in extracts of infected insects. These antibodies would be useful for monitoring production of the viral insecticide, TM Biocontrol-1, which by license must contain only OpMNPV, and to confirm that insect mortality after aerial spraying with this insecticide is attributable to OpMNPV infection.     

Beagle狗肾细胞及用于制备乙脑活疫苗的研究

Ｂｅａｇｌｅ乳狗（５－１０日龄）肾块用热消化法制成细胞批放液氮保存,检定合格后做下列试验：（１）复苏培养长满单层后更换维持液,其细胞能维持４天以上,克服了常规消化培养细胞维持时间短（３６小时）的缺陷。（２）传代１４－２株病毒时,１代病毒的滴度即达６．０４－６．２４ＬｏｇＰＦＵ／ｍｌ,１代后的各代（至１１代）病毒滴度无明显提高。（３）该细胞接种１４－２株病毒时不产生明显的破坏性病变（ＣＰＥ）,在收毒前采取冻溶１次比冻溶前的病毒滴度提高０．２７－０．５ＬｏｇＰＦＵ／ｍｌ。以ＢＤＫ细胞传１代的１４－２株病毒作生产毒种,收毒前冻溶１次等工艺法制备五批疫苗,全面检定结果均符合《乙脑活疫苗规程》的质量标准。其中病毒滴度为６．０９－６．２４ＬｏｇＰＦＵ／ｍｌ;免疫效价（ＩＤ５０＝ｍｌ）为１．９－４．０×１０－５,与相同滴度的原毒株１４－２ＰＨＫ苗对照无明显差异（ｔ＝０．９６８Ｐ＞０．０５）,表明其免疫原性与原毒株相似。     

草地螟阿格姬蜂的滞育诱导和滞育茧的低温贮藏

为了阐明环境因子对草地螟阿格姬蜂Agrypon flexorium (Thunberg)滞育诱导作用, 测定了5个光周期和4个温度处理对阿格姬蜂的滞育诱导和该蜂感受光周期的敏感虫态以及不同时间段低温贮藏对滞育虫茧的影响。结果表明： 在17~23℃、 光照时间10~14 h范围内, 随着温度的降低和光照时间的缩短, 滞育率明显提高。高温能抵消短光照对滞育诱导的影响, 在26℃下, 短光照不能诱导滞育。因此, 低温和短光照是诱导草地螟阿格姬蜂滞育的主要因子。草地螟阿格姬蜂感受滞育信号的敏感虫态为卵和1龄幼虫。卵和1龄幼虫感受滞育信号以后, 需要在滞育环境中发育到老熟幼虫才能全部进入滞育。将室内诱导的滞育茧在4℃左右环境条件下冷藏80 d, 成蜂的羽化率和寄生能力与没有冷藏的非滞育茧差异不显著, 冷藏120 d, 滞育茧仍有71.7%可以正常羽化。结果说明,可在17℃,光周期8L∶16D条件下对寄生后3 d内的草地螟Loxostege sticticalis幼虫进行滞育诱导, 滞育后的虫茧最佳贮藏时间为80 d, 不宜超过120 d。本研究为室内扩繁、 防止蜂源退化、 控制寄生蜂发育时间以便适时释放提供了参考依据。     

The influence of temperature and length of time of storage of frog mucus samples

Frozen, stored mucus has been extensively used for transport studies but there is no clear evidence of the influence that the temperature and length of time of storage may have on the results. We stored frog mucus samples at -20 and -80 degrees C and analysed them on days zero, 2, 10, 30 and 90. At each temperature, a sample was thawed, studied and refrozen on each of the study days, at the same time that one sample was thawed only on the study day. Displacement in a simulated cough machine and on the frog palate, as well as contact angle measurements, were determined for the mucus samples on each study day. Mucus cytologic analyses on each of the study days were done with special regard to neutrophil counts and cell integrity. Friedman analysis of variance did not show any difference between the different periods of storage and the two temperatures for any of the parameters studied. The medians for the relative transport velocity on the frog palate varied between 0.88 and 1.03, for the contact angle between 21 and 28 degrees, and for the displacement in the simulated cough machine between 58 and 95 mm over the 90 days of the experiment. There were no cytologic alterations compatible with cell degeneration. We conclude that the storage of frog mucus either at -20 or -80 degrees C for periods up to 90 days does not lead to any significant differences in mucus transportability.     

Low pH formulation of whole IgG antivenom: impact on quality, safety, neutralizing potency and viral inactivation

Low pH treatment improves the tolerance to intravenous infusion, the stability, and the viral safety of various therapeutic immunoglobulins G preparations, but has never been evaluated for horse plasma-derived antivenoms. We have studied the impact of low pH formulation on the quality, safety, stability, potency and viral inactivation of a whole IgG antivenom used to treat viperid snake bite envenoming. Horse plasma-derived whole immunoglobulins purified by caprylic acid were incubated for 24 h at low pH in the presence of 4% sorbitol, then sterile-filtered and stored liquid at 2-8°C. Appearance, aggregates, purity, safety tests in mice, venom antibody titre, and neutralization potency tests were controlled. Low pH treatment did not affect the physico-chemical characteristics, safety and potency of antivenom for at least 6 months of storage, but a major increase in aggregates was observed. In vitro antibody titre and in vivo neutralizing potency were maintained. There were ≥ 5.5 log inactivation of Herpes Simplex Virus-1, an enveloped virus, but no significant inactivation of the non-enveloped Poliovirus type 3. Low pH treatment appears feasible to improve the viral safety of antivenoms without affecting the neutralization potency. The possibility to formulate antivenoms at low pH requires further investigations to avoid formation of aggregates.     

Insecticidal properties and microbial contaminants in a Spodoptera exigua multiple nucleopolyhedrovirus (Baculoviridae) formulation stored at different temperatures

The Spodoptera exigua (Hübner) multiple nucleopolyhedrovirus (SeMNPV) is currently being tested as a biological insecticide for use in greenhouse crops in southern Spain. We performed a study in which semipurified SeMNPV occlusion bodies (OBs) were formulated in phosphate-buffered saline, pH 6.5, with 5% (vol:vol) glycerol and 0.15% (wt:vol) sorbic acid, and they were stored at -20, 4, or 25 degrees C during 18 mo. Initial aerobic counts (+/-SE) averaged 1.4 (+/-0.17) x 10(7) colony-forming units/ml after 17-h incubation at 37 degrees C. Aerobic counts of microorganisms that contaminated OB formulations stored at 250C decreased markedly over the period of the study, whereas only small decreases were observed in counts from OBs stored at 4 or -20 degrees C. The principal microbial contaminants of OB suspensions were Enterococcus spp., Enterobacteriaceae, and yeasts. Potential human pathogens (Salmonella, Shigella, and Vibrio species) were not detected, and populations of Staphylococcus aureus and Bacillus cereus were extremely low. Compared with newly formulated OBs, the estimated LD50 values of OBs stored at 25 degrees C increased by >16,666-fold over the 18 mo of storage, whereas LD50 values were not greatly affected by storage at 4 or -20 degrees C. Significant changes over time in OB concentrations were only observed in the 25 degrees C treatment. Complete degradation of viral DNA was observed at 25 degrees C but not in refrigerated or frozen OBs. We conclude that OB formulation with bacteriostatic or antioxidant additives, together with storage and distribution in refrigerated conditions, will likely result in an SeMNPV biopesticide shelf life that exceeds 18 mo.     

Storage effects on genomic DNA in rolled and mature coca leaves

Rolled and mature leaf tissue was harvested from Erythroxylum coca var. coca Lam. (coca) to determine a method for storage that would maintain DNA with high quality and content up to 50 days. Harvesting coca leaf tissue under Andean field conditions often requires storage from 3 to 10 days before extraction where tissue integrity is lost. All samples of rolled and mature coca leaf tissue were harvested and separately stored fresh in RNAlater for 50 days at 4 degrees, -20 degrees, and 23 degrees C, while similar samples were air-dried for 72 h at 23 degrees C or oven-dried for 72 h at 40 degrees C after storage, before extraction. Triplicate samples of each tissue type were extracted for DNA at 10-day intervals and showed that DNA integrity and content were preserved in leaf tissue stored at 4 degrees and -20 degrees C for 50 days. Rolled and mature leaf tissue stored at 4 degrees, -20 degrees, and 23 degrees C showed insignificant degradation of DNA after 10 days, and by day 50, only leaf tissue stored at 4 degrees and -20 degrees C had not significantly degraded. All air- and oven-dried leaf tissue extracts showed degradation upon drying (day 0) and continuous degradation up to day 50, despite storage conditions. Amplified fragment length polymorphism analysis of DNA from rolled and mature leaf tissue of coca stored at 4 degrees and -20 degrees C for 0, 10, and 50 days showed that DNA integrity and content were preserved. We recommend that freshly harvested rolled or mature coca leaf tissue be stored at 4 degrees, -20 degrees, and 23 degrees C for 10 days after harvest, and if a longer storage is required, then store at 4 degrees or -20 degrees C.     

Changes of viability and composition of the Escherichia coli flora in faecal samples during long time storage

Long-time storage of faecal samples is necessary for investigations of intestinal microfloras. The aim of the present study was to evaluate how the viability and the composition of the Escherichia coli flora are affected in faecal samples during different storage conditions. Four fresh faecal samples (two from calves and two from infants) were divided into sub-samples and stored in four different ways: with and without addition of glycerol broth at -20 degrees C and at -70 degrees C. The viability and the phenotypic diversity of the E. coli flora in the sub-samples were evaluated after repeated thawings and after storage during 1 year. The samples stored for 1 year without thawing were also kept at room temperature for 5 days and subsequently analysed. According to phenotyping (PhP analysis) of 32 isolates per sample on day 0, all four samples contained two dominating strains of E. coli each, and between one and eight less common strains. Samples that were stored at -70 degrees C in glycerol broth showed equal or even higher bacterial numbers as the original samples, even after repeated thawings, whereas samples stored at -20 degrees C showed a considerably lower survival rate, also with addition of glycerol. Sub-samples containing glycerol broth that were kept at room temperature after storage for 1 year showed a clear increase in the number of viable cells as well as in diversity. The diversities in each sub-sample showed a tendency to decrease after several thawings as well as after storage. Generally, the E. coli populations in samples stored at -20 degrees C were less similar to the population of the original sample than that in samples stored at -70 degrees C. Samples that had been mixed with glycerol broth had an E. coli flora more similar to that in the original sample than those without glycerol broth. Furthermore, the sub-samples that were kept at room temperature after storage for 1 year generally were more similar to the original samples than if they were processed directly. We conclude that for long time storage of faecal samples, storage at -70 degrees C is preferable. If samples have to be thawed repeatedly, addition of glycerol is preferable both for samples stored at -70 degrees C and for samples stored at -20 degrees C. Our data also have indicated that when E. coli isolates from faecal samples are selected for, e.g. analysis of virulence factors, it is necessary to pick several isolates per sample in order to obtain at least one isolate representing the dominating strain(s).     

Growth of enterotoxigenic Staphylococcus aureus in povi masima, a traditional Pacific island food

AIMS: To obtain preliminary data on the microbiology and hurdles to pathogen growth in the traditional Pacific Island food, povi masima, which is essentially beef brisket cured in brine. METHODS AND RESULTS: Six containers of povi masima were prepared and two were inoculated with five enterotoxigenic strains of Staphyloccocus aureus. The povi masima were divided into two lots each containing two uninoculated control and an inoculated container. Lot 1 was incubated at room temperature (20 degrees C) and lot 2 under refrigeration (4-5 degrees C) for up to 98 days. During storage, samples were removed and tested for aerobic plate count, coagulase-producing Staphylococci, Clostridium perfringens, staphylococcal enterotoxin and various chemical parameters of the food. Coagulase-producing Staphylococci and aerobic plate counts grew to high levels in both the inoculated and uninoculated lots stored at room temperature, but enterotoxin was only detected at one time point in these lots and this may represent a false positive result. The concentration of NaCl in the meat increased with time as concentrations equilibrated, and nitrite was rapidly lost in those lots stored at room temperature. Storage at 4-5 degrees C prevented proliferation of coagulase-producing Staphylococci. CONCLUSIONS: For safe curing and storage, this food should be kept under refrigeration as this prevented growth of staphylococci. Optimum storage would also be achieved with improved attempts to ensure equal distribution of NaCl prior to storage. SIGNIFICANCE AND IMPACT OF THE STUDY: Under conditions traditionally used to cure and store this food, enterotoxigenic staphylococci can grow to numbers where toxigenesis might occur, especially during the early stages of curing where the salt has not diffused from the brine into the meat.     

Relationship between dead cells and DNA fragmentation in bovine embryos produced in vitro and stored at 4 degrees C.

DNA fragmentation and its relationship with dead cells were examined in bovine blastocysts produced in vitro and stored at 4 degrees C for 1-5 days. Survival and development to the hatching and hatched blastocyst stage decreased with increasing storage time. Both were significantly lower at 72 hr than at 48 hr. None of the embryos stored for 120 hr developed to the hatching or hatched blastocyst stage. The proportion of dead cells per embryo increased progressively as the time of storage increased, until 69% of embryonic cells were dead after 120 hr of storage. There was no significant difference between the proportions of DNA fragmentation per embryo stored for 0 and 24 hr (12% vs 16%). However, the proportion of DNA fragmentation in embryos stored for longer than 48 hr was significantly greater than that in embryos stored for less than 24 hr. There were no significant differences among those stored for longer than 48 hr (28-33%). These results suggest that the reduced developmental competence of bovine embryos stored at 4 degrees C is characterized by necrotic change rather than apoptotic change.     

蓝花丹开花生物学观测及花粉储存研究

对四川引种栽培的蓝花丹（Plumbago auriculata Lam.）花粉与柱头形态、花部特征及开花物候进行了系统观测,并对其花粉的采集时间与储存温度进行了初步研究。结果显示：（1）两种类型花粉和柱头形态均具有较大差异,短花柱型（S型）花粉的极轴长P值和赤道轴长E值均显著大于长花柱型（L型）花粉,L型柱头则明显长于S型,且两种花粉的纹饰和柱头的瘤状突起物形态也明显不同;（2）蓝花丹具有较高的开花同步性指数（为0.89）,但相对开花强度不高,属于中等强度;（3）蓝花丹两种花型在花蕾半开放时采收花粉,其活力最高,L型花粉活力可达85.24%±4.22%,S型可达87.74%±2.95%;（4）L型与S型花粉分别于25℃干燥0.5 h和1 h后再低温储存,其活力保持更好;（5）干燥后的花粉在-86℃条件下保存效果最好,储存30 d后L型花粉活力高达66.51%±0.85%、S型达69.07%±1.57%。本研究表明蓝花丹二型植株在生殖资源分配上存在明显差异,这种差异一方面导致花粉大小和形态及其所需干燥时间的不同,另一方面导致二型花柱头表现出明显不同的特征,这些差异性的结构是否参与了蓝花丹自交不亲和反应的识别过程,还有待进一步研究。此外,较低的开花强度会造成虫媒传粉困难,这可能是蓝花丹自然结实率极低的重要因素之一。     

假酸浆种子发芽特性研究

在不同温度、不同贮藏时间和方法下,对来源于印度尼西亚的假酸浆种子发芽特性进行研究。结果表明:不同温度对假酸浆种子萌发的影响差异极显著,在15/25℃变温条件下种子发芽率最高,为84.3%,发芽快且整齐;假酸浆种子采收后立即播种其发芽率非常低,室温下贮藏6～9个月时在25℃恒温或15/25℃变温条件下均有较高发芽率,说明假酸浆种子有休眠性,通过延长贮藏时间能打破休眠,促进种子发芽;但室温贮藏15个月后,种子活力下降非常明显。低温冷藏在一定条件下能提高假酸浆种子萌发能力,能延长种子寿命。     

Genetically stable regeneration of apple plants from slow growth

Shoot-tips of apple cultivar `Gala' were stored in vitrousing a low temperature slow-growth culture method. All shoot-tips survived 1-year storage, with a significant height increment over that period. Eight `Gala' single-bud sibling lines were established for genetic analysis. Although cytological examination detected chromosomal variation in plants recovered from slow growth culture, the ploidy remained genetically stable relative to the before-storage cultures. An amplified fragment length polymorphism (AFLP) assay was performed to detect DNA sequence variation. No differences in the DNA fragment patterns were observed using 20 primer combinations between the before-storage and the stored samples. In addition, a methylation sensitive amplified polymorphism (MSAP) assay was performed to investigate the DNA methylation status in both the before-storage and stored samples. It was found that the slow-growth storage resulted in a significant DNA methylation change in the stored shoots compared with the before-storage samples.     

Validation of fluorescent in situ hybridization combined with flow cytometry for assessing interindividual variation in the composition of human fecal microflora during long-term storage of samples

This work was conducted to assess the accuracy of in situ hybridization to show differences in human microflora composition between volunteers and to optimize the storage of fecal samples to allow delayed analysis of gut microflora composition in humans. Fecal samples from 25 healthy subjects (14 women, 11 men aged 24-51) were collected. The samples were fixed in 4% Paraformaldehyde (PFA) solution at 4 degrees C overnight and stored at -70 degrees C. Twenty samples were analysed to quantify the variation due to interindividual differences in the composition of fecal microflora. The five remaining samples were stored either after PFA fixation or directly frozen at -70 degrees C and were monitored on a 12-month period. The fecal microflora was analysed by in situ hybridization combined with flow cytometry detection. Ribosomal RNA-targeted probes were used to assess the relative proportions of four phylogenetic groups: Clostridium coccoides-Eubacterium rectale (Erec 482), Bacteroides (Bac 303), Faecalibacterium prausnitzii (Fprau 645) and Bifidobacterium (Bif 164). Our results demonstrated that the method used is adapted to detect significant differences in fecal microflora composition in humans. Moreover, samples stored in PFA solution demonstrated a stable composition even after 8 months of storage. Conversely, frozen samples were less stable as the Bifidobacterium and C. coccoides-E. rectale groups showed significant differences after 2 months of storage. In conclusion, the fecal microflora composition can be analysed up to 8 months after 4% PFA fixation and storage at -70 degrees C. It represents an extended time compared with the 2-month period currently recommended. This will give more flexibility for applying this technology in epidemiological studies including a large number of samples.     

Efficacy of reconstituted and stored botulinum toxin type A: an electrophysiologic and visual study in the auricular muscle of the rabbit

Once botulinum toxin type A is reconstituted, the manufacturer recommends that it be used in approximately 4 hours. As a result, a significant amount of this costly drug is often discarded because it is not completely used in the recommended period. The purpose of the present study was to compare fresh versus stored reconstituted botulinum toxin type A for (1) initial potency, (2) duration of action, and (3) bacterial colonization.Using a rabbit model, 20 New Zealand White rabbits were divided into four groups (I to IV). All rabbits had an injection of 2.5 U of reconstituted botulinum toxin into the right anterior auricular muscle. The first group was injected with botulinum toxin type A that was freshly reconstituted and served as the control. The second, third, and fourth groups were injected with botulinum toxin type A that had been reconstituted and stored for 2, 6, and 12 weeks, respectively, in a conventional freezer. Each rabbit had daily visual evaluation of the ear, with the position of auricle being graded from I to III. In addition, each rabbit had a nerve conduction study performed on the right anterior auricular muscle before injection and every 2 weeks after injection. Amplitude was chosen as the principal variable in the data analysis because it is the best predictor of physiologic changes at the muscle motor unit level. The endpoint of the study was defined as the time at which the nerve conduction studies and the visual inspections returned to baseline, preinjection levels. Botulinum toxin type A was also cultured before injection into each group.Overall, the nerve conduction data revealed a trend with a faster recovery (return to baseline) with the stored botulinum toxin. Groups IV and III returned to baseline first, followed by groups II and I. However, there was no significant difference among the groups at 2 and 4 weeks after injection, indicating that initial potency was unchanged. The differences between the groups became significant (p < 0.05) at 6 weeks and onward, suggesting that the duration was affected. Group I (fresh botulinum toxin) and group II (toxin stored for 2 weeks) had comparable outcomes and were not significantly different at any time period. Under visual inspection, the mean recovery time for each group was as follows: group IV, 5.4 weeks; group III, 7.0 weeks; group II, 6.75 weeks; and group I, 7.80 weeks. The results showed significance (p < 0.05) beginning after 3 weeks among some groups. Again, there was an overall quicker trend to return to baseline with the longer storage of the botulinum toxin (groups III and IV). These results support the authors' conduction study data, which suggest that the initial potency is not affected but the duration of action is. Again, groups I and II had comparable results. Microbiology cultures showed no growth of either aerobic or anaerobic bacteria at 7 days.In conclusion, using the rabbit model, it seems that reconstituted and stored botulinum toxin type A has the same initial potency but the duration of action is affected sometime after 2 weeks of storage. No bacterial contamination was associated with storing unpreserved reconstituted botulinum toxin type A for up to 12 weeks.     

新鲜土壤样品储存温度和时间对不同形态氮素的影响

土壤氮素形态及含量具有重要的生态学研究意义,而土壤样品的储存对土壤氮素含量的准确测定有很大影响.为了选择合理的土壤样品储存方法,本研究以福建省建瓯市万木林保护区罗浮栲林土壤为研究对象,测定在不同温度(25、4和-20 ℃)、不同储存时间(0、7和30 d)下土壤铵态氮、硝态氮、总氮、可溶性有机氮、氨基酸氮含量和微生物生物量氮,以及冷冻后常温培养过程中的氮素含量.结果表明: 在7 d的储存时间内,除氨基酸氮以外,常温培养样品下其余的氮素含量均有所增加;与新鲜样品相比,冷藏、冷冻样品的所有氮素含量之间均无显著性差异,且氮素含量变化较常温培养下更加稳定.因低温储存样品有刺激氮矿化的效果,在30 d储存时间内,与新鲜样品相比,除可溶性有机氮外,冷藏、冷冻样品的所有氮素含量均显著升高;两种冷储存方法之间无显著差异.因此,新鲜样品带回实验室后应及时处理;如需要冷储藏,时间不要超过半个月.如果需要较长的储存时间,则需将样品放置于更低的温度(-40或-80 ℃).在对储存土壤样品进行培养试验之前,需要进行预培养处理.在预培养过程中,除硝态氮含量呈现先下降再迅速升高的趋势外,其余氮素均随着培养时间逐渐趋近于新鲜土壤样品含量,在培养一周左右恢复到与新鲜土壤样品氮含量最为接近的状态.结合已有研究,对野外取样和风干样品需要5～14 d的预培养,冷储存样品预培养时间不应少于一周.     

弗里熊蜂蜜罐中糖液成分分析

【目的】熊蜂是众多植物的重要传粉昆虫,以采集并贮藏花蜜和花粉为主要食物。本研究旨在探究熊蜂的营养需求及明确其对采集的食物是否存在酿制过程。【方法】利用白砂糖溶液(糖浓度50%)饲喂弗里熊蜂Bombus friseanus蜂群,收集并检测其贮藏在蜜罐中1~7 d的糖液,作为处理组样品;同时将上述白砂糖溶液置于灭菌离心管中,排除熊蜂取食,作为对照组样品,测定贮藏期间处理组和对照组糖液的pH值、糖浓度、糖组分及α-淀粉酶和转化酶活性。【结果】弗里熊蜂B. friseanus贮藏在蜜中1~7d的糖液pH值平均为3.74±0.13,显著低于对照组(6.55±0.15);糖浓度与贮藏时间显著正相关,贮藏6d后糖浓度显著高于贮藏1~3 d时的;糖液组分更加丰富,除蔗糖外利用HPLC还检出果糖、葡萄糖、麦芽糖和海藻糖,贮藏4~5 d的糖液中己糖含量极显著高于贮藏1~3 d和6~7 d时的,己糖和麦芽糖含量分别与蔗糖含量极显著负相关,总糖中果糖和麦芽糖含量与贮藏时间极显著负相关,葡萄糖、蔗糖和海藻糖的含量分别与贮藏时间极显著正相关。贮藏6 d的糖液中α-淀粉酶活性显著高于其他时间,其他贮藏时间样品间α-淀粉酶活性差异不显著,而所有样本的转化酶活性在21.17~38.05 U/g FW之间,随贮藏时间的延长差异不显著。【结论】弗里熊蜂B. friseanus采集人工饲喂的糖溶液贮藏在蜜罐中,经其加工后发生了物理和生物化学变化,揭示熊蜂存在酿蜜能力。本研究的结果为熊蜂生物学及繁育研究提供了参考。     

The quality standardization of a national vaccine against yellow fever

One of the commercial lots of yellow fever vaccine has been attested as the National Branch Standard (NBS) of yellow fever vaccine. This NBS has been studied in all tests required by the regulations for standard vaccines. The NBS has been found to meet the necessary requirements in all its characteristics. The study of the thermostability of the NBS at temperatures of 4-10 degrees C, 20-22 degrees C, 37 degrees C during storage for 24 hours to 1 year has revealed the rapid loss of the infectious capacity of the virus at the above temperatures and its high stability during storage at -20 degrees C. Thus, the NBS has been found to retain the required level of immunizing potency for 3 months at a temperature of 4-10 degrees C, for 1 month at 20-22 degrees C and for 2 weeks (the term of observation) at 37 degrees C. The heat resistance of the NBS of yellow fever vaccine corresponds to the WHO requirements. The newly developed NBS has been used as the standard preparation for controlling 27 lots of commercial yellow fever vaccine.     

Storage deterioration of maize having pre-harvest infection with Aspergillus flavus

Deteriorative changes during storage of two different lots of field-contaminated (by Aspergillus flavus ), equally matured and freshly harvested (from two different fields) maize grains of the same cultivar (Ganga) and genotype, and stored under the same natural atmospheric conditions prevailing in the store-house, were studied and compared. It was found that the rate and extent or grain deterioration were much less in lot-2 than in lot-1 which had relatively high pre-harvest internal fungal ( A. flavus ) load. However, the deteriorative changes of both the lots could be reduced when the initial A. flavus infection was completely eliminated. Furthermore, of these already contaminated lots, the kernels selected as free of such infection at harvest also suffered less deterioration during storage.