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PubMedDate not supplied

Incubation of poliomyelitis as calculated from the time of entry into the central nervous system via the peripheral nerve pathways.

A new theory of how poliovirus reaches the central nervous system (CNS)--that it enters at many peripheral nerve endings with passage along nerve pathways to the CNS, with limited dispersal in the CNS--is used in making predictions of incubation periods, and these are compared with data from the literature and with predictions from other theories. The virus transit speed along the nerve of 2.4 mm/h has been used in calculating the incubation time. The calculated incubation time for Cutter vaccinees is similar to the actual times reported, and the calculated minimal and maximal incubation times in humans are similar to the published ranges. Incubation times in different animals and for different paralyses are explained. The pathology of lesions in humans and the consequent paralyses are compatible with the model. Tonsillectomy-associated poliomyelitis is reviewed and discussed in relation to possible entry of virus from peripheral nerve endings in muscle. Increased lymphocyte concentrations in the muscle may account for continuing susceptibility after tonsillectomy. Severe paralysis following exercise is explained as an effect of increased blood supply to nerves in the CNS that has already been invaded by virus. In developing countries, the phenomenon of paralysis in the injected muscle a few hours after injection in febrile children may occur in a similar fashion. The entry of poliovirus from many sites at nerve endings in muscles is consistent with clinical, experimental, and pathologic data and provides an explanation of the incubation times and related phenomena of poliomyelitis.

Animals↗

PubMed1998

Correlation between intracellular cAMP content, kinematic parameters and hyperactivation of human spermatozoa after incubation with pentoxifylline.

Various compounds have been used in the attempt to improve sperm motility, including pentoxifylline (PF), a methylxanthine derivative. It has been postulated that PF, being a phosphodiesterase inhibitor, increases sperm kinematic parameters and the number of spermatozoa exhibiting hyperactivated motility by raising the intracellular content of cAMP, a molecule involved in the generation of sperm energy. However, it has not been clarified whether the biological effects of PF on sperm motility correlate with its ability to increase intracellular cAMP levels. To examine this relationship, the kinematic parameters, hyperactivation, and intracellular cAMP content were evaluated in motile spermatozoa, obtained by discontinuous Percoll gradient and swim-up from 21 normozoospermic semen samples, incubated without and with PF for 0, 1, 2, and 4 h. PF increased beat cross frequency after 1 and 2 h of incubation, curvilinear velocity and lateral head displacement (ALH) after 4 h, and hyperactivation after 1, 2, and 4 h, and decreased linearity (LIN) after 1 h of incubation. The intracellular cAMP content of spermatozoa incubated with PF increased at all time-points examined. Both intracellular cAMP content and increase in hyperactivation in response to PF decreased with the length of incubation. In the absence of PF, cAMP content was unchanged and was correlated significantly only with ALH and the percentage of spermatozoa with hyperactivated motility. Following incubation with PF, cAMP content correlated with hyperactivation and all sperm kinematic parameters, with the exception of LIN and straightness. These findings suggest that the beneficial effects of PF on sperm kinematic parameters and hyperactivation are related to its ability to increase intracellular cAMP content.

Cyclic AMP↗

PubMed1995

The distribution of incubation periods of infectious disease. 1949.

1. Characteristics of the distribution of incubation periods of a number of infectious diseases, as reported in the literature, have been reviewed. 2. The usual frequency curve of incubation time takes the form of a logarithmic normal curve. This appears to be equally true of diseases with very short and very long incubation periods. 3. The measure of variation in incubation periods used in this study, termed the dispersion factor, is the antilogarithm of the logarithmic standard deviation. Dispersion factors for most of the diseases studied range from 1.2 to 1.5 and are independent of mean length of incubation. 4. Some epidemiological uses for a knowledge of the distribution of incubation time are discussed.

Communicable Diseases↗

PubMed1986

Importance of the use of short and long sperm pre-incubation periods in assessing the fertilizing capacity of human spermatozoa by hamster test.

The fertilizing capacity of semen samples of seven fertile men was studied in vitro using zona-free hamster ova (hamster test). Spermatozoa of each sample were pre-incubated 4 or 24 h before ova were inseminated for 3 h. An extended insemination for an additional 3 h was also performed after the shorter pre-incubation. The overall ovum penetration rate changed from 0 to 100% (mean 52%) after short (4 h) sperm pre-incubation and from 10 to 100% (mean 55%) after long (24 h) pre-incubation. Taking into account the combination of short and long pre-incubation periods, all donors reached a penetration rate of 67 to 100%. The results indicate that both short and long pre-incubation periods must be employed when the hamster test is used diagnostically to assess the fertilizing capacity of human spermatozoa.

Animals↗

PubMed2001

Effect of hatch on the distribution for failure of an embryo to survive incubation.

The objectives of this paper were to validate an improved model to describe failure to hatch by using data obtained from two hatches of a line of chickens and to examine the effect of hatch on the distribution for time of failure of an embryo to survive incubation. Breakout analysis of 11,254 eggs that failed to hatch was used to characterize the distribution for time of failure to survive and the probability of failure to hatch. The distribution for time of failure to survive was modeled by a diphasic Weibull distribution, corresponding to the two phases of increased embryonic mortality during incubation. Distribution parameters for time of failure to survive were estimated by maximum likelihood and minimum Hellinger distance. Goodness-of-fit statistics validated the appropriateness of the diphasic Weibull distribution. Overall, the proportion of infertility was 0.213, and the proportion of embryonic mortality by the end of incubation was 0.086. Among embryos that suffered mortality during incubation, the proportion that died during Phase 1 was 0.77; therefore, 0.23 died during Phase 2. For Phase 1, mean time of mortality was 2.6 d, and standard deviation was 3.3 d. For Phase 2, mean time was 17.4 d, and standard deviation was 2.0 d. Time of mortality was distributed differently in the two hatches; this difference occurred mostly during Phase 1. Failure rates of the two hatches were different during the first 3 d of incubation. The model is useful to assess probability of failure to hatch and the distribution for time of failure to survive during incubation.

Animals↗

PubMed2001

Incubation temperature affects plasma insulin-like growth factors in embryos from selected lines of turkeys.

An experiment was conducted to test the hypothesis that incubator temperature may affect circulating insulin-like growth factors (IGF-I and IGF-II). In prior studies, growth of turkey embryos was altered by increasing incubator temperatures. Interestingly, the embryonic growth of a growth-selected line (F) was reduced, whereas embryos from an egg-production-selected line (E) did not alter embryonic growth but altered organogenesis. Growth of the F and E lines was altered experimentally in the current study by increasing incubator temperature from 36.8 to 37.2 C during the last 3 d of incubation. Embryonic blood samples were taken and analyzed for glucose, glucagon, IGF-I, and IGF-II concentrations. Increased incubator temperature elevated embryonic plasma glucose concentrations of all treatments compared to controls, which was accompanied by increased plasma glucagon concentration only in the E line embryos. Line and treatment interacted to affect IGF-I and IGF-II concentrations of embryo and hatchlings. Line E embryos increased IGF-I in response to the higher temperature, but controls did not; F embryos altered IGF-II in response to treatment, but controls did not. Alterations in IGF-I in E corresponded to growth responses, whereas IGF-II in F corresponded to metabolic responses. We concluded that changes in turkey embryo growth rates to incubator temperature involved changes in IGF-I. Additionally, IGF-II and glucagon are involved in intermediary metabolism during higher temperature exposure.

Animals↗

PubMed2003

Effects of storage time on incubating egg gas pressure, thyroid hormones, and corticosterone levels in embryos and on their hatching parameters.

Incubating eggs (1,800 total) produced by a commercial flock of Cobb broiler breeders were used to determine the effects of storage duration (3 and 18 d) on gas partial pressure, thyroid hormones, and hatching parameters. Partial pressure of oxygen (pO2) and carbon dioxide (pCO2) were measured on d 18 and at internal pipping (IP) during incubation. Blood samples were collected for determination of triiodothyronine (T3), thyroxine (T4), and corticosterone concentrations in the embryos at IP and in newly hatched chicks. From 464 to 510 h of incubation, eggs were checked individually every 2 h to determine the timing and duration of IP, external pipping (EP), and total hatching time. At 18 d of incubation and at IP, pCO2 was greater in air cell of eggs stored for 3 d compared to those stored for 18 d (P < 0.05), but pO2 was greater in eggs stored for 18 d. At IP, T3 and corticosterone levels were higher in plasma of the embryos of eggs stored for 3 d compared to those stored for 18 d, but it was the reverse in newly hatched chicks (P < 0.05). Embryos from eggs stored for 18 d required more time to complete IP compared to embryos of eggs stored for only 3 d (P < 0.05), whereas the duration of EP was not affected by storage. The overall longer incubation was, however, not only due to prolonged IP but also to later occurrence of IP. It was concluded that prolonged IP as a result of long storage may be related to the late increase in corticosterone level, which may be a necessary stimulus for higher T3/T4 ratio, late increase in pCO2 level, and decrease in pO2. The effect of long storage was a delay in hatching and a continuous increase in T3 due to higher corticosterone levels between IP and hatching, which may be an indication of the more stressful event of hatching of embryos from eggs stored longer. Differences in pCO2, pO2, T3, T4, and corticosterone levels in the incubating eggs may be manifestations of these changes culminating in altered hatching parameters and consequently differences in chick quality and growth potentials.

Animals↗

PubMed1989

Plasma prolactin levels in incubating turkey hens during pipping of the eggs and after introduction of poults into the nest.

Plasma levels of prolactin (Prl) associated with incubation and maternal behavior were compared in turkey hens allowed to incubate 10 fertile eggs (Group I, n = 9) or 10 infertile eggs (Group II, n = 7) in open nest boxes. At the end of the day that the first egg hatched, all unhatched eggs were removed from Group I hens and each hen was given 10 poults. At the end of the following day, infertile eggs were removed from Group II hens and each hen was given 10 poults. Although pipping of the eggs changed the incubation behavior of Group I hens, it had no effect on plasma Prl. Subsequent hatch of the eggs and/or presence of poults resulted, within 24 h, in a sharp fall in Prl levels, abandonment of the nests, and a shift to maternal behavior. Visual and auditory exposure to Group I poults had no effect on plasma Prl or incubation behavior of Group II hens incubating infertile eggs in adjacent pens. However, within 24 h after the infertile eggs were exchanged for newly hatched poults, Prl levels in Group II hens declined sharply and the hens abandoned the nests and showed maternal behavior similar to that observed in Group I hens. No significant relationships were found in either group between plasma Prl levels and quality of incubation or maternal behavior.

Animals↗

PubMed1996

Association of oviduct-specific glycoproteins with human and baboon (Papio anubis) ovarian oocytes and enhancement of human sperm binding to human hemizonae following in vitro incubation.

The objectives of this study were 1) to determine whether or not human and baboon oviduct-specific glycoproteins (human OGP, baboon OGP) would associate with ovarian oocytes during in vitro incubation in a manner similar to that detected in vivo for oviductal oocytes and 2) to determine whether the association of OGP with ovarian oocytes influenced sperm binding. In vitro association of OGP with ovarian oocytes was assessed by indirect immunofluorescence assay using a polyclonal antibody prepared against human or baboon OGP. Human and baboon ovarian oocytes incubated in culture media containing OGP showed association of OGP with the zona pellucida (ZP) as detected by bright fluorescence. A similar pattern of fluorescence was observed in baboon oviductal oocytes (positive control). No fluorescence of the ZP was detected from ovarian oocytes incubated with culture medium alone. The pattern of fluorescence for ovarian oocytes incubated with OGP and serum albumin, the major oviductal fluid protein, was similar to that for oocytes incubated with OGP alone. A modified hemizona assay was used to assess whether association of human OGP with human ovarian oocytes influenced sperm binding. The number of sperm bound to hemizonae in the presence of human OGP was significantly greater (p < 0.01) than the number bound to hemizonae in the control culture medium. Addition of antibodies specific for human OGP to the incubation medium 1 h prior to addition of gametes blocked the enhancement of sperm binding seen in the presence of human OGP alone. Finally, human hemizona assays conducted in the presence of baboon OGP resulted in a significant decrease (p < 0.05) in the number of sperm bound per zona compared with that in culture medium alone despite high homology between human and baboon OGP. These results 1) suggest that human OGP associates with ovulated oocytes in vivo; 2) support the hypothesis that association of OGP with the ZP may play a role in fertilization, possibly through enhancing the binding of sperm to the ZP within the oviduct; and 3) suggest that a homologous system (i.e., gametes and oviductal glycoprotein from the same species) is necessary for study of the function of oviductal glycoproteins.

Animals↗

PubMed1997

Reduction of sperm cholesterol:phospholipid ratio is a possible mechanism for enhancement of human sperm binding to the zona pellucida following incubation with phosphatidylcholine liposomes.

TEST (TES (N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid) and Tris) yolk buffer (TYB) has recently been shown to improve the binding capacity of spermatozoa to zona pellucidae. The present study had two objectives: 1) to elucidate which component(s) of TYB dominates this effect and 2) to define the responsible mechanism. Sperm samples obtained from subfertile men were incubated for 2 h in either TYB or media containing egg yolk lipoproteins or phospholipids. After incubation, sperm binding was tested by the hemizona assay. Yolk lipoprotein-treated spermatozoa bound hemizonae with efficiency equal to that of the spermatozoa incubated in control medium. Conversely, incubation of spermatozoa in media containing either TYB, yolk-phospholipids, or pure phosphatidylcholine (PC) resulted in a 2- to 3-fold increased binding capacity (p < 0.01). A close correlation was found between the effect of yolk-phospholipids and TYB on the binding capacity of the same sperm samples, compared to spermatozoa incubated in control medium. Incubation of spermatozoa in yolk phospholipid medium caused a dose-dependent increase of sperm binding capacity (p < 0.05). Treatment of sperm samples with 1 mg/ml or more of purified PC preparation also resulted in a reduction of the sperm cholesterol:phospholipid molar ratio. Significant correlations between the effects of the treatments on sperm cholesterol: phospholipid molar ratio and sperm binding were obtained with yolk-phospholipids (r = -0.55) or 1 mg/ml purified PC (r = -0.61). We conclude that 1) the enhanced binding capacity of human spermatozoa following TYB treatment is probably due to yolk-phospholipids, mainly egg yolk PC; and 2) it appears that the enhanced binding capacity of human spermatozoa following treatment with egg yolk-containing media may be a result of the reduction of the cholesterol:phospholipid molar ratio in the sperm cells.

Acrosome↗

PubMed1999

Incubation temperature influences sex-steroid levels in juvenile red-eared slider turtles, Trachemys scripta, a species with temperature-dependent sex determination.

Incubation temperature determines gonadal sex in the red-eared slider turtle, Trachemys scripta. However, little is known about the long-term effects of incubation temperature on traits other than gonadal sex in this species. To investigate the hypothesis that incubation temperature (independent of gonadal sex) influences sex steroid levels after hatching, we incubated eggs of the red-eared slider turtle at three temperatures (26, 28.6, and 31 degrees C). We then measured plasma levels of dihydrotestosterone, estradiol, progesterone, and testosterone in 6-wk-old males from 26 degrees C and 28.6 degrees C eggs, and in 6-wk-old females from 28.6 degrees C and 31 degrees C eggs. We found that dihydrotestosterone levels were not influenced by incubation temperature or gonadal sex. However, progesterone levels were significantly higher in males from 26 degrees C eggs than in males from 28.6 degrees C eggs. In contrast, testosterone levels did not differ between males from 26 degrees C versus males from 28.6 degrees C eggs, but they were significantly higher in females from 28.6 degrees C than in females from 31 degrees C eggs. Progesterone and testosterone levels did not differ between males and females from 28.6 degrees C eggs. Temperature also influenced estradiol levels in both sexes, but the effects were enigmatic. We conclude that incubation temperature has lasting effects on sex steroid levels even after hatching.

Animals↗

PubMed2002

The incubation period of kuru.

BACKGROUND: Kuru is a transmissible spongiform encephalopathy that was identified in Papua New Guinea in the late 1950s. Several thousand cases of the disease occurred during a period of several decades. Epidemiologic investigations implicated ritual endocannibalistic funeral feasts as the likely route through which the infectious agent was spread. METHODS: We estimated the incubation period distribution of kuru using a back-calculation model and explored the relation among sex, age at infection, and incubation period. Key assumptions in the model were that the number of new kuru infections in a year was proportional to the number of kuru cases dying that year, and that the epidemic arose from a single case of sporadic Creutzfeldt-Jakob Disease occurring around 1900. RESULTS: The mean incubation period of kuru was estimated at between 10.3 and 13.2 years. Point estimates of the 90th percentile ranged from 21.1 to 27.0 years. The incubation period in females was estimated to be shorter than that in males. The shortest incubation periods were estimated in adult women, who may have been exposed to the largest doses of infectious material. CONCLUSIONS: Our findings suggest that the relatively young age of cases of variant Creutzfeldt-Jakob disease probably reflects increased levels of exposure in young people, rather than age-dependency in the incubation period.

Adolescent↗

PubMed1999

Prolonged survival of corneal allografts incubated in alloantibody fragments.

BACKGROUND: In this study, we determined the binding characteristics of F(ab')2 alloantibody fragments to corneal antigens and assessed the capacity of these antibody fragments to protect corneal allografts from immune attack. METHODS: Goat anti-rabbit alloantibodies were pepsin-digested and labeled with 125I, and the time course of association and dissociation of the F(ab')2 fragments was determined. Corneal allografts were incubated in unlabeled F(ab')2 fragments and transplanted into allogeneic recipients, and the graft survival times were recorded. RESULTS: Binding of radiolabeled F(ab')2 fragments to rabbit cornea cells reached a maximum at 12 hr. At 32 degrees C (rabbit corneal temperature), the radiolabel eluted rapidly from the cornea, reaching baseline at 72 hr. At 4 degrees C (corneal graft storage temperature), significant amounts remained associated with the cornea at 96 hr. Mean survival time for grafts incubated in F(ab')2 anti-rabbit fragments was significantly greater than that of grafts incubated in nonimmune F(ab')2 fragments. Three of the corneal allografts incubated in goat F(ab')2 anti-rabbit fragments survived for 100 days, whereas the longest surviving control allograft incubated in goat F(ab')2 nonimmune fragments was rejected on day 24. Preincubation of corneas in unlabeled, immune F(ab')2 fragments followed by incubation in radiolabeled, immune F(ab')2 fragments suggested that antigen masking was not a factor in the prolongation of graft survival. CONCLUSION: Based on the binding and release kinetics and the graft survival times, it appears that the protective effect of immune F(ab')2 fragments extends well beyond the binding interval of the antibody fragments to corneal cell membranes.

Animals↗

PubMed2001

The costs of egg production and incubation in great tits (Parus major).

The costs of egg production and incubation may have a crucial effect on avian reproductive decisions, such as clutch size and the timing of reproduction. We carried out a brood-size enlargement experiment on the great tit (Parus major), in which the birds had to lay and incubate extra eggs (full costs), only incubate extra eggs (free eggs) or did not pay any extra cost (free chicks) in obtaining a larger brood. We used female fitness (half the recruits produced plus female survival) as a fitness measure because it is the female which pays the costs of egg production and incubation, and because clutch size is under female control. Female fitness decreased with increasing costs (fitness of free chicks females is higher than that of free eggs females which is higher than that of full costs females). These fitness differences were due to differences in female survival rather than in the number of recruits produced. This is the first time that the costs of egg production and incubation have been estimated using such a complete fitness measure, including, as our measure does, the local survival to the following year of both the female and her offspring. Our results emphasize that reproductive decisions cannot be understood without taking egg production and incubation costs into account.

Animals↗

PubMed2003

Differential investment and costs during avian incubation determined by individual quality: an experimental study of the common eider (Somateria mollissima).

Individuals of different quality may have different investment strategies, shaping responses to experimental manipulations, thereby rendering the detection of such patterns difficult. However, previous clutch-size manipulation studies have infrequently incorporated individual differences in quality. To examine costs of incubation and reproductive investment in relation to changes in clutch size, we enlarged and reduced natural clutch sizes of four and five eggs by one egg early in the incubation period in female common eiders (Somateria mollissima), a sea duck with an anorectic incubation period. Females that had produced four eggs (lower quality) responded to clutch reductions by deserting the nest more frequently but did not increase incubation effort in response to clutch enlargement, at the cost of reduced hatch success of eggs. Among birds with an original clutch size of five (higher quality), reducing and enlarging clutch size reduced and increased relative body mass loss respectively without affecting hatch success. In common eiders many females abandon their own ducklings to the care of other females. Enlarging five-egg clutches led to increased brood care rate despite the higher effort spent incubating these clutches, indicating that the higher fitness value of a large brood is increasing adult brood investment. This study shows that the ability to respond to clutch-size manipulations depends on original clutch size, reflecting differences in female quality. Females of low quality were reluctant to increase investment at the cost of lower hatch success, whereas females of higher quality apparently have a larger capacity both to increase incubation effort and brood care investment.

Animals↗

PubMed2006

Fitness cost of incubation in great tits (Parus major) is related to clutch size.

Life-history theory predicts that parents produce the number of offspring that maximizes their fitness. In birds, natural selection on parental decisions regarding clutch size may act during egg laying, incubation or nestling phase. To study the fitness consequences of clutch size during the incubation phase, we manipulated the clutch sizes during this phase only in three breeding seasons and measured the fitness consequences on the short and the long term. Clutch enlargement did not affect the offspring fitness of the manipulated first clutches, but fledging probability of the subsequent clutch in the same season was reduced. Parents incubating enlarged first clutches provided adequate care for the offspring of their first clutches during the nestling phase, but paid the price when caring for the offspring of their second clutch. Parents that incubated enlarged first clutches had lower local survival in the 2 years when the population had a relatively high production of second clutches, but not in the third year when there was a very low production of second clutches. During these 2 years, the costs of incubation were strong enough to change positive selection, as established by brood size manipulations in this study population, into stabilizing selection through the negative effect of incubation on parental fitness.

Animals↗

PubMed1967

Allagochrome II. Effects of Light and Substrate on Allagochrome and Chlorogenic Acid Levels of Incubated Sunflower Leaf Discs.

Sunflower leaf discs incubated in the light on carbohydrate substrates exhibit several-fold increases in amounts of extractable allagochrome and chlorogenic acid. These changes are linear with time, and oxygen is required. The light effect saturates at approximately 600 muW/cm(2) "white" light, roughly the compensation point for photosynthesis. Red light is as effective as white light. Incubation in the dark, or in far red light, produces negligible changes in allagochrome and chlorogenic acid content.Sucrose (0.2 m) has been used as the standard substrate. At this concentration, glucose and fructose are slightly more effective. The optimum temperature range for incubation is 20 to 30 degrees . Allagochrome and chlorogenic acid values of both light and dark incubated samples decrease between 30 and 50 degrees , approaching zero at 50 degrees . Net light effects decrease to zero between 40 and 50 degrees .Of the inhibitors tested, 2,4-dinitrophenol, hydroxylamine and salicylaldoxime have no effect on light enhanced allagochrome and chlorogenic acid values except at high concentrations (which are generally deleterious to leaf tissues and cause decreased values for both dark and light incubated samples). Net light effects are completely inhibited, without changes in values of dark incubated discs, by azide (0.1 to 1 mm) and dichlorophenyldimethylurea (1 to 10 mum).Leaf tissues from the xantha mutant of Helianthus annuus do not exhibit a light effect. The absence of light effects in nonphotosynthetic leaf tissue and the inhibiting effects of photosynthetic poisons suggest that the photosynthetic apparatus is somehow involved.An hypothesis for light regulated metabolism via phenolic synthesis is discussed.

Journal Article↗

PubMed1992

Interactive effects of solutes, potassium sorbate and incubation temperature on growth, heat resistance and tolerance to freezing of Zygosaccharomyces rouxii.

The interactive effects of solutes, potassium sorbate and incubation temperature on growth, heat resistance and tolerance to freezing of Zygosaccharomyces rouxii were investigated. Growth rates in media supplemented with glucose, sucrose or NaCl to aw 0.93 were more rapid than in unsupplemented media (aw 0.99). Although growth in unsupplemented medium was lower at 35 degrees C, incubation at 21 degrees C or 35 degrees C had little effect on growth in media supplemented with glucose and sucrose. The addition of 300 micrograms potassium sorbate/ml to media resulted in reduced growth rates, particularly at 35 degrees C. Heat resistance of Z. rouxii was substantially greater in cultures previously incubated at 35 degrees C than in cultures incubated at 21 degrees C in media both with and without 300 micrograms potassium sorbate/ml. Zygosaccharomyces rouxii was tolerant to freezing at -18 degrees C for up to 120 d in all test media supplemented with glucose, sucrose or NaCl. The addition of 300 micrograms potassium sorbate/ml to sucrose-supplemented media resulted in increased resistance to freezing in cultures previously incubated at 21 degrees C. Sensitivity to freezing increased when cultures were incubated at 21 degrees C in media not supplemented with solutes. Glucose and sucrose provided the best protection against inactivation by heating and freezing, regardless of the presence of potassium sorbate in growth media.

Adaptation, Biological↗