Stages Of Hibernation Research Articles

Expression of TLR2/4 on Epididymal Spermatozoa of the Chinese Soft-Shelled Turtle Pelodiscus sinensis During the Hibernation Season.

Spermatozoa are known to be stored in the epididymis of the Chinese soft-shelled turtle Pelodiscus sinensis for long periods during hibernation, but the mechanism that underlies the sperm storage is poorly understood. This study was carried out to confirm the presence of TLR2/4 (Toll-like receptor 2/4) in epididymal spermatozoa during the hibernation season and to analyze whether TLRs play a role in sperm storage. The structure and ultrastructure of a spermatozoon during the hibernation stage were investigated using light- and transmission electron-microscopy. RT-PCR was used to analyze mRNA expression, while protein expression was determined via Western blot. TLR2/4 mRNA and proteins were detected in spermatozoa. Immunofluorescence staining was used to confirm TLR2/4 localization in the spermatozoon, and TLR2/4 were localized in the midpiece and the posterior segment of the head of the spermatozoon, which corresponded to the cytoplasmic droplets (CDs) of the turtle spermatozoon. As TLRs play critical roles in detecting and responding to invading pathogens, this study provided molecular evidence that TLR2/4 might contribute to sperm storage in the epididymides. Anat Rec, 299:1578-1584, 2016. © 2016 Wiley Periodicals, Inc.

Yearly occurrence of maely bug Nipaecoccus viridis on citrus trees in Abu-Graib in Baghdad- Iraq

A study was conducted in orchard at Abu-Ghraib county located within Baghdad province for a full year starting from the beginning of June 2014 to the end of June 2015. Three peaks appeared, the first peak was in the first week of July as reached 77.5 insect/tree and the degree of the upper and lower temperature and relative humidity were 44 C°, 27.3C° and 22%, respectively. While the second peak was in the second week of October reached 141 insect/tree when the degree of the upper and lower temperature and relative humidity were 39.2 C°, 17.9 C° and 41%, respectively. Then the mealy bug (Nipaecoccus viridis) numbers decreased until the insect has entered the hibernation stage in early January of 2015 which continued for three months till April, after that mealybug begun to spread and reached its highest peak in the second week of July which was 21.4 insect/tree when the degree of the upper and lower temperature and relative humidity were 42 C°, 25 C° and 21%, respectively. Then, numbers of mealybug declined and fluctuated till the end of July. The environmental studies which study of factors affecting the increase in the population of the pest and bio-number occupies privileged position between studies because they represent the main pillars in integrated pest management programs.

Cytological study on Sertoli cells and their interactions with germ cells during annual reproductive cycle in turtle.

Sertoli cells (SCs) play a central role in the development of germ cells within functional testes and exhibit varying morphology during spermatogenesis. This present study investigated the seasonal morphological changes in SCs in the reproductive cycle of Pelodiscus sinensis by light microscopy, transmission electron microscopy (TEM), and immunohistochemistry. During hibernation period with the quiescent of spermatogenesis, several autophagosomes were observed inside the SCs, the processes of which retracted. In early spermatogenesis, when the germ cells started to proliferate, the SCs contained numerous lipid droplets instead of autophagosomes. In late spermatogenesis, the SCs processes became very thin and contacted several round/elongated spermatids in pockets. At this time, abundant endoplasmic reticulum and numerous mitochondria were present in the SCs. The organization of the tight junctions and the adherens junctions between the SCs and germ cells also changed during the reproductive cycle. Moreover, SCs were involved in the formation of cytoplasmic bridges, phagophores, and exosome secretions during spermatogenesis. Tubulobulbar complexes (TBC) were also developed by SCs around the nucleus of the spermatid at the time of spermiation. Strong, positive expression of vimentin was noted on the SCs during late spermatogenesis compared with the hibernation stage and the early stage of spermatogenesis. These data provide clear cytological evidence about the seasonal changes in SCs, corresponding with their different roles in germ cells within the Chinese soft‐shelled turtle Pelodiscus sinensis.

Serum Biochemical Reference Values for Adult and Non-adult Chinese Alligators during the Deep and Late Hibernation Periods

Background: The Chinese alligator (Alligator sinensis) is a critically endangered species. Due to the rapid growth of the captive population, the susceptibility to disease during the recovery period after winter hibernation, especially in young alligators, have detrimentally affected Chinese alligator populations. Serum biochemistry, which relates to metabolism, nutritional status and disease, is enormously helpful in evaluating physical conditions in reptile. Many studies have reported the serum biochemical reference values of various reptilian species, including several crocodilians. However, reference values for Chinese alligators have not yet been reported. For captive Chinese alligators, hibernation is a crucial period because winter management has a direct influence on the survival rate of juveniles and the reproduction rate of adults. The main object of the present study refore was to measure the serum biochemical values of captive Chinese alligators during hibernation.Materials, Methods & Results: As such, this study investigates the serum biochemistry as a factor of age and hibernation stage. During the deep and late hibernation periods blood samples were drawn from 30 healthy captive Chinese alligators (adults, sub-adults, and juveniles) at the Anhui Research Center of Chinese Alligator Reproduction (ARCCAR). Serum biochemical measurements were performed using an automated biochemical analyzer and compared based on the age group and hibernation stage via two-way ANOVA. During late hibernation, serum lactate dehydrogenase, alkaline phosphatase, and aspartate aminotransferase activity increased in all age groups in comparison to that in deep hibernation, while the concentration of calcium decreased. Meanwhile, the concentration of serum phosphorus, uric acid, total protein, and globulin in sub-adults and juveniles considerably increased in comparison to that in deep hibernation, while cholesterol and albumin declined. However, in adults only slight changes were noted. Based on comprehensive statistical analysis, our results indicate that sub-adults and juveniles are at risk of developing renal disease during artificial hibernation.Discussion: Chinese alligators, especially sub-adults and juveniles, are particularly vulnerable to disease when they wake from hibernation. They often display symptoms such as depression, anorexia, lethargy, sluggish movement, slow, incremental weight gain, progressive muscle wasting, and even death. The high rate of morbidity in non-adult Chinese alligators may be associated with the high density of UA and other changes in multiple biochemical markers that occur during late hibernation. These altered serum biochemical profiles may indicate kidney damage. One of the most common diseases among reptiles is nephropathy, the symptoms of which are non-specific and tend to agree with those observed post-hibernation. In summary, this study has reported the serum biochemical values of Chinese alligators of varying ages in the deep and late hibernation phases. Based on statistical analyses, interesting differences between the serum biochemical values of adults and non-adults during the deep and late hibernation have been found. The observed changes suggest that, under an artificial hibernation environment, the kidneys of sub-adults and juveniles may become impaired. We believe that the data reported in this study will provide clinical guidance to facilitate more appropriate artificial wintering conditions for Chinese alligators, and assist the breeding and management of these reptiles, as well as disease prevention, during hibernation and recovery.

Changes in the Golgi Apparatus of Neocortical and Hippocampal Neurons in the Hibernating Hamster.

Hibernating animals have been used as models to study several aspects of the plastic changes that occur in the metabolism and physiology of neurons. These models are also of interest in the study of Alzheimer's disease because the microtubule-associated protein tau is hyperphosphorylated during the hibernation state known as torpor, similar to the pretangle stage of Alzheimer's disease. Hibernating animals undergo torpor periods with drops in body temperature and metabolic rate, and a virtual cessation of neural activity. These processes are accompanied by morphological and neurochemical changes in neurons, which reverse a few hours after coming out of the torpor state. Since tau has been implicated in the structural regulation of the neuronal Golgi apparatus (GA) we have used Western Blot and immunocytochemistry to analyze whether the GA is modified in cortical neurons of the Syrian hamster at different hibernation stages. The results show that, during the hibernation cycle, the GA undergo important structural changes along with differential modifications in expression levels and distribution patterns of Golgi structural proteins. These changes were accompanied by significant transitory reductions in the volume and surface area of the GA elements during torpor and arousal stages as compared with euthermic animals.

Expression of TLR2/4 in the sperm-storing oviduct of the Chinese soft-shelled turtle Pelodiscus sinensis during hibernation season.

The initiation of innate immunology system could play an important role in the aspect of protection for sperms long-term storage when the sperms got into oviduct of turtles and come into contact with epithelium. The exploration of TLR2/4 distribution and expression in oviduct during hibernation could help make the storage mechanism understandable. The objective of this study was to examine the gene and protein expression profiles in Chinese soft-shelled turtle during hibernation from November to April in the next year. The protein distribution of TLR2/4 was investigated in the magnum, isthmus, uterus, and vagina of the turtle oviduct using immunohistochemistry, and the gene expression of TLR2/4 was analyzed using quantitative real-time PCR (qRT-PCR). The results showed positive TLR2 protein expression primarily in the epithelium of the oviduct. TLR4 immunoreactivity was widely observed in almost every part of the oviduct, particularly in the epithelium and secretory gland membrane. Analysis of protein, mRNA expression revealed the decreased expression of TLR2/4 in the magnum compared with the isthmus, uterus, and vagina during hibernation. The protein and mRNA expression of TLR2 in the magnum, isthmus, uterus, and vagina was decreased in April compared with that in November. TLR4 protein and mRNA expression in the magnum, isthmus, uterus and vagina was decreased in November compared with that in April. These results indicated that TLR2/4 expression might protect the sperm from microbial infections. In contrast to the function of TLR2, which protects sperm during the early stages of hibernation, TLR4 might play a role in later stages of storage. The present study is the first to report the functions of TLR2/4 in reptiles.

Opposing activity changes in AMP deaminase and AMP-activated protein kinase in the hibernating ground squirrel.

Hibernating animals develop fatty liver when active in summertime and undergo a switch to a fat oxidation state in the winter. We hypothesized that this switch might be determined by AMP and the dominance of opposing effects: metabolism through AMP deaminase (AMPD2) (summer) and activation of AMP-activated protein kinase (AMPK) (winter). Liver samples were obtained from 13-lined ground squirrels at different times during the year, including summer and multiples stages of winter hibernation, and fat synthesis and β-fatty acid oxidation were evaluated. Changes in fat metabolism were correlated with changes in AMPD2 activity and intrahepatic uric acid (downstream product of AMPD2), as well as changes in AMPK and intrahepatic β-hydroxybutyrate (a marker of fat oxidation). Hepatic fat accumulation occurred during the summer with relatively increased enzymes associated with fat synthesis (FAS, ACL and ACC) and decreased enoyl CoA hydratase (ECH1) and carnitine palmitoyltransferase 1A (CPT1A), rate limiting enzymes of fat oxidation. In summer, AMPD2 activity and intrahepatic uric acid levels were high and hepatic AMPK activity was low. In contrast, the active phosphorylated form of AMPK and β-hydroxybutyrate both increased during winter hibernation. Therefore, changes in AMPD2 and AMPK activity were paralleled with changes in fat synthesis and fat oxidation rates during the summer-winter cycle. These data illuminate the opposing forces of metabolism of AMP by AMPD2 and its availability to activate AMPK as a switch that governs fat metabolism in the liver of hibernating ground squirrel.

Hematology of three age groups of captive Chinese alligator during deep and late hibernation

As the numbers and density of the farmed Chinese alligator (Alligator sinensis) increase, diseases are more common. Death often occurs during the recovery period from hibernation and this phenomenon is particularly prominent in juveniles. A practical way is therefore needed to monitor the health of the alligator. Research on hematology can provide an early warning and a rapid diagnosis of a disease and will help decrease mortality during recovery from hibernation. The aim of this study was to determine the hematologic values of the Chinese alligator at different stages of hibernation. We collected 30 blood samples from each of three age groups (adults, sub-adults, juveniles) during deep and late hibernation. We obtained counts of red blood cells, thrombocytes, and total and different white blood cells using manual methods. The thrombocyte numbers in the three groups decreased significantly during late compared with deep hibernation. The white blood cell counts for the sub-adults and juveniles increased significantly during late hibernation, whereas this did not occur in the adults. The immunity of the sub-adults and juveniles clearly increased during late hibernation. The results suggest that, for breeding programs, environmental stress may be the cause of the higher mortality in the juveniles during recovery from hibernation.

Life‐history traits and climatic responsiveness in noctuid moths

Emergence phenology has been shown to advance considerably in the past decades in many lepidopterans. Noctuid moths (Noctuidae) constitute a species‐rich family of lepidopterans with a large diversity of life history traits presumably driving climatic responsiveness. In our study we aim to assess the role of life‐history and ecological traits in climatic responsiveness of noctuid moths, whilst controlling for phylogenetic dependence. We used a long‐term dataset of European noctuid moths collected from a light‐trap in northeastern Hungary. As the study site is located at the intersection of several biogeographical zones harbouring a large number of noctuid moth species, our dataset provides a unique possibility to investigate the moths’ climatic sensitivity. To estimate the role of life‐history traits and ecological factors in driving lepidopterans’ response to climatic trends, we employed three proxies related to the species’ ecology (habitat affinity, food plant specialization and food type) and two robust types of life‐history traits (migration strategy and hibernation form). The degree of temporal shifts of various measures of emergence phenology was related to hibernation stage, food type and migration strategy. Large‐scale phylogenetic relatedness exerted little constraint in all models fitted on each measure of phenology. Our results imply that noctuid moths overwintering as adults exhibited greater degrees of phenological shifts than species hibernating as larvae or pupae. It implies that moths hibernating as adults are forced to suspend activity in our climate and the prolongation of autumn activity might be the result of increased plasticity in flight periods.

Maternal effects influence phenotypes and survival during early life stages in an aquatic turtle

Summary Offspring phenotypic variation can be substantially influenced by non‐genetic factors such as maternal effects, which ultimately can influence organismal fitness. For oviparous organisms that lack parental care, oviposition‐site choice and egg size are maternal effects that can greatly affect offspring traits. Yet, few studies examine the consequences of these traits in the wild. We manipulated the contents of natural painted turtle nests such that offspring spent two life stages (incubation and hibernation) in either maternally selected nest sites or randomly selected nest sites and quantified treatment differences in environmental parameters and offspring phenotypes. Additionally, we tracked the fates of individual eggs and hatchlings, which allowed us to quantify the strength and form of selection acting on egg size during incubation and, for the first time, body size during hibernation. Maternally selected nest sites were warmer and produced offspring that were longer and hatched earlier than their siblings emerging from cooler, randomly selected nests. Treatments did not affect any measured traits during hibernation. We detected no selection on egg size during the incubation stage, but significant linear selection favouring larger hatchlings during hibernation. Our results suggest that nest‐site choice allows mothers to partially control the environment of their incubating eggs, but is less effective at controlling hatchling environments during hibernation. Additionally, we provide novel support for the ‘bigger‐is‐better’ hypothesis in turtles by showing a positive relationship between size and survival during the hibernation stage.

THE EFFECTS OF HIBERNATION AND CAPTIVITY ON GLUCOSE METABOLISM AND THYROID HORMONES IN AMERICAN BLACK BEAR (URSUS AMERICANUS)

American black bears (Ursus americanus) have been shown to become transiently insulin resistant and hypothyroid during winter, but no studies have investigated these changes in long-term captive bears or in bears which remain awake year-round. Wild, captive hibernating, and captive nonhibernating bears were evaluated at times corresponding to three of their major physiologic stages: fall (hyperphagic stage), winter (hibernation stage), and summer (normal activity stage). Combined insulin and glucose tolerance tests and thyroid hormone profiles were performed on all bears during each stage. All three groups of bears had evidence of insulin resistance during the winter, as compared to the summer or fall, based on glucose tolerance curves. Analysis of thyroid hormone concentration varied and distinct patterns or similarities were not apparent. While obesity in captive American black bears is multifactorial, the finding that, regardless of their ability to hibernate, captive bears retain similar physiology to their wild counterparts indicates that captive bears' complex physiologic changes need to be addressed in their management.

Morphofunctional changes in the small intestine epithelium of the frog Rana temporaria in the course of hibernation

The structure and function of small intestine epithelium have been studied in overwintering frogs at various stages of hibernation. Experiments on the in vitro absorption of arginine vasotocin (AVT) have shown that the epithelium ability for absorption of this nonapeptide without hydrolysis persists during hibernation. However, there is a decline in AVT absorption observed in January–February and later on (as compared with that in October–December) which is most pronounced in March–April. Changes in the epithelial structure appear by midwinter and are growing towards spring. In April–May, enterocyte height decreased by 33%, microvilli length by 40%, and number of mitochondria by 57% relative to the values at the beginning of hibernation. The absence of signs of breakdown attests to the adaptive nature of the observed changes. The dynamics of the studied parameters reveals morphological and functional plasticity of small intestinal epithelium in Rana temporaria over the hibernation period.

Tissue Distribution of S‐(2‐Succino)cysteine (2SC), a Biomarker of Mitochondrial Stress in Obesity and Diabetes

S-(2-succino)cysteine (2SC) is a chemical modification of proteins produced by reaction of fumarate with thiol groups in protein, a process known as succination. We propose to use the name S-(2-succino)cysteine (instead of S-(2-succinyl)cysteine) from this point on. This is to distinguish protein succination (in which fumarate forms a thioether linkage with cysteine residues) from succinylation (in which an ester, thioester or amide bond would be formed). Succination of proteins is increased in muscle of type 1 diabetic rats and in adipose tissue in type 2 diabetic mice. The increase in 2SC is a direct result of tissue accumulation of fumarate in response to nutrient excess and resultant mitochondrial stress in diabetes. In this study, we examine the breadth of succination of tissue proteins in the db/db type 2 model of diabetes. We also determined the extent of succination in epididymal adipocytes of type 1 (Akita, streptozotocin (STZ)) and type 2 (ob/ob, db/db) diabetic mice, in diet-induced obese (DIO) mice, and in the adipose tissue of ground squirrels in various stages of hibernation. While succination was not increased in most tissues (brain, heart, kidney, liver, skeletal muscle) in the db/db model of diabetes, it was increased in all adipose beds of type 2 diabetic and DIO mice in comparison to their controls. Succination was not increased in adipocytes of type 1 diabetic mice. Adipose tissue from hibernating (HIB) 13-lined ground squirrels was also studied to determine if obesity in the absence of hyperglycemia affected succination of proteins. There were no differences in succination of proteins in brown or white adipose tissue over the torpor-arousal cycle. We conclude that 2SC is a biomarker of nutrient excess and mitochondrial stress in adipose tissue, increasing under the hyperglycemic and insulin resistant conditions associated with type 2 diabetes and obesity.

Renal Protection From Prolonged Cold Ischemia and Warm Reperfusion in Hibernating Squirrels

We have previously shown that cold ischemia (CI) results in massive increases in caspase-3 activity, tubular apoptosis, and brush border injury (BBI) in mouse kidneys. During hibernation, the 13-lined ground squirrel (GS) cycles through repeated CI during torpor, followed by warm ischemia/reperfusion (WI) during interbout arousal (IBA). We sought to determine whether CI and WI during hibernation caused caspase-3 activation, tubular apoptosis, acute tubular necrosis, or BBI, and reduced renal function. We also determined whether protection was dependent on the stage of hibernation. Radiotelemeters were implanted in 1-year-old GS, and core body temperature was remotely monitored. GS kidneys at various stages of hibernation were subjected to ex vivo CI. Tubular apoptosis was not detected and caspase-3-like activity was not different between hibernating and summer kidneys. Despite prolonged CI followed by WI and reperfusion, acute tubular necrosis and apoptosis did not occur in hibernating kidneys. BBI was absent in torpid kidneys but significantly increased in IBA kidneys and associated with an increase in caspase-3-like activity, suggesting that IBA kidneys are more susceptible to injury than summer or torpid kidneys. Renal function and urine concentrating ability diminished during torpor but returned during IBA. Despite BBI, IBA kidneys clear serum creatinine and concentrate urine. Kidneys from both summer and hibernating animals tolerated ex vivo CI, confirming that protection from apoptotic and necrotic cell death is independent of the stage of hibernation. An understanding of how renal protection occurs during hibernation may help in understanding the pathophysiology of delayed graft function.

Structure of the 100S Ribosome in the Hibernation Stage Revealed by Electron Cryomicroscopy

In the stationary growth phase of bacteria, protein biosynthesis on ribosomes is suppressed, and the ribosomes are preserved in the cell by the formation of the 100S ribosome. The 100S ribosome is a dimer of the 70S ribosome and is formed by the binding of the ribosome modulation factor and the hibernation promoting factor. However, the binding mode between the two 70S ribosomes and the mechanism of complex formation are still poorly understood. Here, we report the structure of the 100S ribosome by electron cryomicroscopy and single-particle image analysis. The 100S ribosome purified from the cell in the stationary growth phase is composed of two transfer RNA-free 70S ribosomes, has two-fold symmetry, and is formed through interactions between their 30S subunits, where interactions between small subunit proteins, S2, S3 and S5, appear to be critical for the dimerization.

Genomic analysis of miRNAs in an extreme mammalian hibernator, the Arctic ground squirrel

MicroRNAs (miRNAs) are 19- to 25-nucleotide-long small and noncoding RNAs now well-known for their regulatory roles in gene expression through posttranscriptional and translational controls. Mammalian hibernation is a physiological process involving profound changes in set-points for food consumption, body mass and growth, body temperature, and metabolic rate in which miRNAs may play important regulatory roles. In an initial study, we analyzed miRNAs in the liver of an extreme hibernating species, the Arctic ground squirrel (Spermophilus parryii), using massively parallel Illumina sequencing technology. We identified >200 ground squirrel miRNAs, including 18 novel miRNAs specific to ground squirrel and mir-506 that is fast evolving in the ground squirrel lineage. Comparing animals sampled after at least 8 days of continuous torpor (late torpid), within 5 h of a spontaneous arousal episode (early aroused), and 1-2 mo after hibernation had ended (nonhibernating), we identified differentially expressed miRNAs during hibernation, which are also compared with the results from two other miRNA profiling methods: Agilent miRNA microarray and real-time PCR. Among the most significant miRNAs, miR-320 and miR-378 were significantly underexpressed during both stages of hibernation compared with nonhibernating animals, whereas miR-486 and miR-451 were overexpressed in late torpor but returned in early arousal to the levels similar to those in nonhibernating animals. Analyses of their putative target genes suggest that these miRNAs could play an important role in suppressing tumor progression and cell growth during hibernation. High-throughput sequencing data and microarray data have been submitted to GEO database with accession: GSE19808.

Shotgun Proteomics Analysis of Hibernating Arctic Ground Squirrels

Mammalian hibernation involves complex mechanisms of metabolic reprogramming and tissue protection. Previous gene expression studies of hibernation have mainly focused on changes at the mRNA level. Large scale proteomics studies on hibernation have lagged behind largely because of the lack of an adequate protein database specific for hibernating species. We constructed a ground squirrel protein database for protein identification and used a label-free shotgun proteomics approach to analyze protein expression throughout the torpor-arousal cycle during hibernation in arctic ground squirrels (Urocitellus parryii). We identified more than 3,000 unique proteins from livers of arctic ground squirrels. Among them, 517 proteins showed significant differential expression comparing animals sampled after at least 8 days of continuous torpor (late torpid), within 5 h of a spontaneous arousal episode (early aroused), and 1-2 months after hibernation had ended (non-hibernating). Consistent with changes at the mRNA level shown in a previous study on the same tissue samples, proteins involved in glycolysis and fatty acid synthesis were significantly underexpressed at the protein level in both late torpid and early aroused animals compared with non-hibernating animals, whereas proteins involved in fatty acid catabolism were significantly overexpressed. On the other hand, when we compared late torpid and early aroused animals, there were discrepancies between mRNA and protein levels for a large number of genes. Proteins involved in protein translation and degradation, mRNA processing, and oxidative phosphorylation were significantly overexpressed in early aroused animals compared with late torpid animals, whereas no significant changes at the mRNA levels between these stages had been observed. Our results suggest that there is substantial post-transcriptional regulation of proteins during torpor-arousal cycles of hibernation.

Activities of Escherichia coli ribosomes in IF3 and RMF change to prepare 100S ribosome formation on entering the stationary growth phase

The canonical ribosome cycle in bacteria consists of initiation, elongation, termination, and recycling stages. After the recycling stage, initiation factor 3 (IF3) stabilizes ribosomal dissociation by binding to 30S subunits for the next round of translation. On the other hand, during the stationary growth phase, it has been elucidated that Escherichia coli ribosomes are dimerized (100S ribosome formation) by binding ribosome modulation factor (RMF) and hibernation promoting factor (HPF), leading to a hibernation stage. This indicates that 100S ribosomes are formed after these factors are scrambled for ribosomes concomitantly with transition from the log phase to the stationary phase. In this study, to elucidate the ribosomal events before 100S ribosome formation, the relationships between protein factors (RMF and HPF) involved in 100S ribosome formation and IF3 involved in initiation complex formation were examined. As a result of in vitro assays, it was found that ribosomal dissociation activity by IF3 fell, and that ribosomal dimerization activity by RMF and HPF was elevated more when using stationary-phase ribosomes than when using log-phase ribosomes. This suggests that ribosomes change into forms which are hard to bind with IF3 and easy to form 100S ribosomes by RMF and HPF concomitantly with transition from the log phase to the stationary phase.

동면 중 한국산 다람쥐 신장의 복합당질 변화

한국산 다람쥐를 단계적으로 <TEX>$6^{\circ}C$</TEX> 온도로 낮추어 인위적 동면을 유도하였다. 동면은 3개월부터 유도되었으며 9개월간 사육하였다. 동면중 급격한 생리적 변화에 따른 형태 및 복합당질의 변화를 관찰하였다. 형태적으로 동면초기 응축된 사구체 구조와 발견되는 것외 동면중에도 유사한 신장 구조를 나타내었다. Lectin조직화학에 대한 반응은 크게 동면초기에 일시적으로 증가하는 반응군, 동면진행에 따라 증가하는 반응군 및 감소하는 반응군으로 대별할 수 있다. 동면초기에 일시적으로 증가하는 반응은 근위곡요세관의 Con A, 원위곡요세관의 PNA, Con A, 집합관의 DBA, sWGA가 현저하였다. 동면이 진행됨에 따라 현저히 증가하는 반응은 원위곡요세관의 SBA반응이었으며, 감소하는 반응은 모든 세관의 sWGA반응이었다. 유사한 형태적 구조를 가지나 다양한 lectin반응의 변화는 동면중 나타나는 급격한 신장 생리 변화와 연관성이 있는 것으로 유추되며, 이러한 반응성은 동면 중 신장 기능 변화에 대한 마크로 유용할 것이다. Though relatively little is known of the physiology involved, there is reduced kidney activity during hibernation. In this experimental study, male Korean chipmunks (Tamias sibiricus barberi) were maintained in cold conditions (<TEX>$6^{\circ}C$</TEX>) for 9 months, in an attempt to mimic conditions occurring during seasonal hibernation. The examination was made to determine changes of glycoconjugates on the kidney after hibernation by lectin histochemistry. The changes of lectin affinities in the kidney categorize into three groups: a) increase ones only in the early hibernation stage b) increase ones during hibernation and c) decrease ones during hibernation. The transient increase of Con A affinity in the proximal convoluted tubules were demonstrated only in the early cold-treated stage, and PNA and Con A in the distal convoluted tubules and DBA and sWGA in the collecting tubules. SBA affinity tended to increase with hibernation in the proximal convoluted tubules, but sWGA affinities were significantly decreased in the all tubule examined with hibernation. The present results suggest that the glycosylation pattern of the kidney undergoes profound changes during hibernation, and is probably associated with transiently reduced renal function.

Changes in serum sex steroid levels throughout the reproductive cycle of Bufo arenarum females

The changes in the serum levels of the sexual steroids estradiol-17β (E 2), testosterone (T), dihydrotestosterone (DHT), and progesterone (P) in Bufo arenarum females were determined by radioimmunoassay (RIA) during 3 consecutive cycles (1999–2001). The serum concentrations of T and DHT, which showed a close parallelism during the annual reproductive cycle, exhibited the highest levels during the preovulatory period, when oogenesis is advanced, while lowest serum levels of these hormones were found during the ovulatory period. The data obtained for E 2 showed a pattern contrary to that determined for androgens. The maximum E 2 concentrations detected in the early postovulatory period might be associated with vitellogenesis and follicular growth. Lowest E 2 concentrations were reached during the period in which B. arenarum undergoes its final hibernation stage. Serum P showed a peak during the preovulatoy period, related to the induction of nuclear maturation in full grown oocytes. A strong decrease in the levels of the circulating hormones was observed after ovariectomy. Our results showed that, out of the four hormones examined, T and DHT were the best indicators of ovarian and oviductal stage, as shown by the strong positive correlation found between androgen levels and organ weight, while E 2 showed a weak negative correlation with ovarian and oviductal weight.