香樟叶肉含晶细胞季节变化研究

为探讨香樟(Cinnamomum camphora)叶肉含晶细胞超微结构的季节变化,阐明香樟叶肉中草酸钙晶体在春夏秋冬的变化规律。该研究以多年生香樟(C. camphora)叶片为材料,分别于春夏秋冬四个季节露地取样,制作超薄切片,用透射电子显微镜(TEM)观察叶肉含晶细胞超微结构的变化。结果表明:春季时香樟叶肉中只有少数细胞有草酸钙晶体,数量较少,晶体结构多为柱状晶、方晶; 夏季时香樟叶肉细胞中随机分布于液泡的草酸钙晶体明显比春季的数量多、体积大、形态丰富,晶体多为柱状晶、方晶、针晶、簇晶; 秋季时香樟叶肉细胞草酸钙晶体和夏季的类似,数量较多,形态多样,以方晶和柱状晶针晶为主,伴有晶簇; 冬季时香樟叶肉含晶细胞晶体形态为柱状晶、方晶、针晶,数量比夏季和秋季的数量略有减少。该研究结果表明在一年四季中香樟叶肉细胞液泡中均有草酸钙晶体结构存在。     

Thyroid function, pituitary structure and serum lipids in Great Lakes coho salmon, Oncorhynchus kisutch Walbaum, 'jacks' compared with sexually immature spring salmon

Whereas spring salmon, Oncorhynchus kisutch , from Lake Ontario had no overt thyroid goiters, comparable Lake Erie spring salmon had a 44% goitre incidence. Goitre incidence in sexually precocious 'jacks' from Lakes Ontario and Michigan was 43–45% and 100% in 'jacks' from Lake Erie.
All fish displayed thyroid hyperplasia. The degree of hyperplasia (as indicated by thyroid follicle colloid content, thyroid follicle size and shape and thyroid follicle epithelial cell size) in Lake Ontario fish tended to be greater in the 'jacks' than in the spring fish; the reverse was true in Lake Erie fish. Serum total L-thyroxine (T4) concentrations in Lake Ontario spring fish were higher than in any other group. There were no differences in serum T, levels between the groups of 'jacks', nor were serum T, levels in 'jacks' and spring salmon from Lake Ontario significantly different. Serum total triiodo-thyronine (T) concentrations in Lake Ontario spring salmon were significantly higher than in all other groups and that in Lake Erie spring salmon greater than in all groups of 'jacks'. Serum T, levels in Lake Ontario 'jacks' were higher than in Lake Erie 'jacks'. Serum free fatty acid (FFA) and cholesterol levels showed significant interlake differences with lower levels present in Lake Erie salmon. Lake Erie 'jacks' appeared to have fewer and less well vacuolated pituitary gonadotropic basophils than 'jacks' from Lakes Michigan and Ontario. Putative thyrotrop cells appeared to be more numerous and more active in the Lake Erie spring salmon compared with Lake Ontario spring salmon. Prolactin, corticotrop and melanotrop cells appeared less active in spring salmon than in the 'jacks'.     

Pathogenic and Nonpathogenic Acanthamoeba spp. in Thermally Polluted Discharges and Surface Waters1

During spring and autumn, the total number of amoebae and the number of Acanthamoeba species able to grow at 37°C were determined in six thermally polluted factory discharges and the surrounding surface waters. The isolated Acanthamoeba strains were studied for growth in axenic medium, cytopathic effect in Vero cell cultures, and virulence in mice. Although more amoebae were isolated in autumn, the number of Acanthamoeba species was lower than in spring, when the percent of pathogenic strains among the isolates was highest. Higher concentrations of amoebae were found in warm discharges, and more virulent strains occurred in thermal discharges than in surface waters.     

Influence exerced by the season on the modifications of lipid metabolism induced by an increase of the ambiant temperature in the rat]

A fast increase of 10 degrees C (from 24 degrees C up to 34 degrees C) of the ambient temperature alters the male rat lipid metabolism differently if the experiment takes place in autumn or in spring. Generally to this change of temperature, the rat seems to react more in spring than in autumn.     

Ultrastructural characteristics of the thyroid C cells in the summer,autumn and winter states of the hedgehog (Erinaceus europaeus L.), with some reference to other mammalian species

Summary Thyroid glands from spring, summer, autumn and winter states of the hedeghog Erinaceus europaeus L., were fixed by perfusion with glutaraldehyde. After secondary fixation with OsO₄ and embedding in araldite the thyroid C cells were examined in the electron microscope. The fine structural characteristics of the spring and summer C cells were essentially similar to those of a variety of non-hibernating mammals. High synthetic activity in autumn was succeeded by a high secretion and exhaustion phase in hibernation. The changes observed closely resembled those observed by other workers in four different species of bat and were considered to be generally in accord with current opinions on the function of the thyroid (and ultimobranchial) C cells.

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Zusammenfassung Die parafollikulären C-Zellen in der Schilddrüse des winterschlafenden europäischen Igels (Erinaceus europaeus L.) wurden bei Frühjahrs-, Sommer-, Herbst- und Wintertieren elektronenmikroskopisch untersucht. Bei Frühjahrs- und Sommertieren gleicht ihre Feinstruktur weitgehend dem Feinbau parafollikulärer Zellen einer Reihe von Säugetieren, die keinen Winterschlaf halten. Im Herbst wurde eine Phase starker synthetischer Aktivität beobachtet, der eine winterliche Phase der Erschöpfung und Entleerung der spezifischen Granula folgt. Diese Befunde entsprechen weitgehend den Beobachtungen anderer Autoren an vier winterschlafenden Fledermausarten und stimmen mit den gegenwärtigen Ansichten über die Funktion der C-Zellen der Ultimobranchialkörper und der Schilddrüse überein.

     

Seasonal patterns in feeding ecology of three small fishes in the Biandantang Lake, China

Feeding ecology of three small fish species, Hypseleotris swinhonis, Ctenogobius giurinus and Pseudorasbora parva was studied seasonally in the Biandantang Lake, a small, shallow lake in central China. Gut length, adjusted for total body length, was significantly higher in spring than in other seasons for all the three species. Seasonal changes in gut length were not associated with changes in food quality. Weight of fore-gut contents, adjusted for body weight, was significantly higher in winter and spring than in summer and autumn in H. swinhonis and C. giurinus , and significantly higher in autumn than in spring and summer for P. parva. Percentage of empty fore-guts was highest in summer and lowest in spring for H. swinhonis and C. giurinus , and highest in winter and lowest in autumn for P. parva. Diet of the three small fishes showed apparent seasonal changes, and these changes reflected partly the seasonal fluctuations of food resources in environment. Diet breadth was high in winter and low in autumn for H. swinhonis , high in winter and low in spring and summer for C. giurinus , and high in autumn and low in spring for P. parva. Diet overlaps between pairs of species were biologically significant in most cases, except between H. swinhonis and P. parva in summer and autumn and between C. giurinus and P. parva in autumn.     

Sexual size dimorphism, sex ratio and the relationship between seasonality and water quality in four species of Gordiida (Nematomorpha) from Catamarca, Argentina

A total of 687 adult nematomorphs of four species of Gordiida: Chordodes brasiliensis (393 specimens), Noteochorododes cymatium (47 specimens), N. talensis (162 specimens) and Pseudochordodes dugesi (85 specimens) were collected during a period of 1 year from El Simbolar stream, Argentina. Free-living worms were abundant during autumn and spring, but their number decreased during winter and summer. Males were shorter and significantly more abundant than females. The presence of N. cymatium, N. talensis and P. dugesi was correlated with water temperature and these species were most abundant in winter and spring. The presence of C. brasiliensis was correlated with flow rate and pH; this species was more abundant in autumn and winter. These four species are sympatric.     

2021-2022年春、秋季嵊泗列岛浮游植物群落状况及长期变化特征

为更好地了解嵊泗列岛海域在人类活动和气候变暖影响下的生态现状以及变化特征,于2020年秋季和2021年春季在该海域进行了浮游植物的拖网与水样采集及环境要素分析。水采样品中共检出浮游植物6门54属105种。其中,硅藻33属68种,甲藻14属30种,蓝藻、金藻和隐藻各2属2种,绿藻1属1种。春、秋季浮游植物主要优势种为骨条藻(Skeletonema spp.),并在秋季占据绝对优势(Y=0.975)。春季平均细胞丰度[(7.17±7.78)个/mL]明显低于秋季[(77.23±73.44)个/mL]。春季Shannon-Wiener多样性指数和Pielou均匀度指数均高于秋季。Spearman相关分析表明,浮游植物丰度与水温和透明度呈显著正相关,与盐度呈显著负相关。冗余分析显示,浮游植物群落组成与水温、营养盐密切相关。网采样品中共检出浮游植物4门46属94种,硅藻占比最大;春、秋季平均细胞丰度分别为838.17×10³和19406.43×10³个/m³。与水样相比,骨条藻仍为主要优势种,且优势度更高;网采获得的秋季多样性指数和均匀度指数(分别为0.23和0.05)低于水采(分别为0.38和0.10)。将本次网采结果与1990年、2007年调查资料对比发现,嵊泗列岛春、秋季浮游植物群落组成发生了明显改变:丰度明显升高,硅甲藻占比无明显变化,暖水种种类数明显增加,骨条藻优势地位增强,多样性指数和均匀度指数下降。这可能与变暖与富营养化加剧相关。近30年来,溶解无机氮在春季无显著变化,但在秋季显著升高;活性磷酸盐浓度在春、秋季均显著降低;氮磷比在春、秋季均显著升高。浮游植物的变化特征较好地指示了嵊泗列岛海域在富营养化和气候变暖下的生态环境变化。     

Towards a new understanding of migration timing: slower spring than autumn migration in geese reflects different decision rules for stopover use and departure

According to migration theory and several empirical studies, long‐distance migrants are more time‐limited during spring migration and should therefore migrate faster in spring than in autumn. Competition for the best breeding sites is supposed to be the main driver, but timing of migration is often also influenced by environmental factors such as food availability and wind conditions. Using GPS tags, we tracked 65 greater white‐fronted geese Anser albifrons migrating between western Europe and the Russian Arctic during spring and autumn migration over six different years. Contrary to theory, our birds took considerably longer for spring migration (83 days) than autumn migration (42 days). This difference in duration was mainly determined by time spent at stopovers. Timing and space use during migration suggest that the birds were using different strategies in the two seasons: In spring they spread out in a wide front to acquire extra energy stores in many successive stopover sites (to fuel capital breeding), which is in accordance with previous results that white‐fronted geese follow the green wave of spring growth. In autumn they filled up their stores close to the breeding grounds and waited for supportive wind conditions to quickly move to their wintering grounds. Selection for supportive winds was stronger in autumn, when general wind conditions were less favourable than in spring, leading to similar flight speeds in the two seasons. In combination with less stopover time in autumn this led to faster autumn than spring migration. White‐fronted geese thus differ from theory that spring migration is faster than autumn migration. We expect our findings of different decision rules between the two migratory seasons to apply more generally, in particular in large birds in which capital breeding is common, and in birds that meet other environmental conditions along their migration route in autumn than in spring.     

SEASONAL CHANGE IN THE DISTRIBUTION OF CELL SIZE OF COCCONEIS SCUTELLUM VAR. ORNATA (BACILLARIOPHYCEAE) IN RELATION TO GROWTH AND SEXUAL REPRODUCTION1

Growth and sexual reproduction of the marine littoral diatom Cocconeis scutellum Ehrenb. var. ornata Grun. were investigated at 30 different combinations of temperature (5, 10, 14, 18, 22° C), irradiance (20, 60, 100 μE·m^?2·s^?1) and daylength (14:10 and 10:14 h LD cycle). Growth occurred at all combinations. The optimal growth was observed at 14–18° C, long daylength and highest-to-moderate irradiance, and at 18° C, short daylength and highest irradiance. Sexual reproduction on the other hand occurred between 5 and 18° C, and the optimal condition was 10–14° C and short daylength. Annual cyclic, and sesonal changes in the distribution of cell size (valve length) were observed in a field population. These changes were characterized by an annual minimum in mean cell size in autumn, an annual maximum in winter, a slight decrease from the mean in spring–middle summer, a rapid decrease from the mean in late summer–early autumn, and appearance of bimodal distribution of cell size in winter. These changes were caused by sexual reproduction in autumn, rapid growth in late summer–early autumn and slow growth in other seasons, and poor viability of small cells near the lower end of the size range.     

Seasonal variability of macroinvertebrate assemblages in two regions of South Africa: implications for aquatic bioassessment

Seasonal variability of macroinvertebrate assemblages was examined in two regions of South Africa: Western Cape and Mpumalanga. Sampling was undertaken at reference sites using the rapid bioassessment method SASS4 (South African Scoring System, Version 4). This study examined the influence of sampling season on the occurrence of taxa, macroinvertebrate assemblages and SASS scores. In the Western Cape a few taxa were more common at certain times of the year, and multivariate analysis of macroinvertebrate assemblages showed that assemblages grouped by season. The number of taxa and the Average Score per Taxon (ASPT) were significantly different among seasons in the Western Cape, with fewer taxa recorded in winter compared to summer, and significantly higher ASPT values recorded in winter and spring than summer and autumn. Whereas more taxa were recorded in autumn than in spring, a higher proportion of sensitive and high-scoring taxa were recorded in spring. In Mpumalanga macroinvertebrate assemblages did not group by season, and differences in SASS scores were not significant, although more taxa were recorded in winter than in spring or autumn, and ASPTs were slightly higher in winter than in spring. Results are discussed in relation to ecological reference conditions and the interpretation of bioassessment data.     

Marine phytoplankton at the Weddell Sea ice edge: Seasonal changes at the specific level

Summary The Antarctic ice edge acts as a dynamic frontal system on the phytoplankton in the water column. Austral spring and autumn cruises to the Weddell Sea ice edge provided the opportunity to compare phytoplankton at the beginning of biological spring and at the end of biological autumn. The USCGC icebreakers Westwind (1983) and Glacier (1986) went into the sea ice, and the RV Melville (1983 and 1986) completed the transects in the adjacent open ocean. Field samples were observed alive on board ship to record different lifestages near the ice edge. In both seasons cell numbers were low under the ice, and single cells or short chains were the common growth habit. In spring in the open ocean, long chains of vegetative cells with large vacuoles and gelatinous colonies of diatoms and of prymnesiophytes dominated; in autumn in the open ocean close to the accreting ice edge, short chains, single cells, and resting spores were mostly packed with storage products. Enlarged cell diameters and auxospores also occurred near the ice cover in the autumn. Species from the following genera are included: the diatoms Leptocylindrus, Stellarima, Thalassiosira, Eucampia, Corethron, and Chaetoceros, the prymnesiophyte Phaeocystis, and the chrysophyte Distephanus.     

The formation of proventriculus block, alimentary activity and mortality of flea Amphipsylla primaris primaris infected with Yersinia pestis

The results of experiments held in 1982-1983 in Tuva plague natural focus with flea Amphipsylla primaris primaris (Jordan et Rothschild, 1915) from natural populations, whish were inflected and fed on specific host--flat-headed vole (Alticola strelzovi), are analyzed. The initial infectivity of the insects in autumn was higher than in spring: 90 and 50 % respectively. Accumulation of the agent in aggregated form in the organism of A. p. primaris, estimated by the quantity of fleas with and partial blocks, was more active in imago of both sexes in autumn than in spring, while sucking flea were observed in spring more often than in autumn. Irrespective of season, the part of males with visible accumulations of Y. pestis was more, and their alimentary activity was higher than that of females. Fleas died much more quickly in spring. Part of the males with proventriculus block exceeded that of females in spring experiment. Females with alimentary canal obstruction prevailed in autumn. Thus, sex of the insect and season of the experiment conducting influenced on all studied indices. Besides that, Y pestis ability for the proventriculus block formation in fleas during different seasons can change by the opposite way depending on sex of the ectoparasites.     

Migratory Masked Shrikes,Lanius nubicus staging at the desert edge: phenology,and sex- and age-related differences in body mass

Migratory Masked Shrikes (Lanius nubicus) were mist-netted during the spring and autumn migrations at Eilat, Israel. Nearly four times more shrikes were trapped during spring than in autumn. This could be explained by either the species assorting to loop migration, or a higher capture rate owing to poor body condition after crossing the Sahara in spring. In spring, no differences in phenology were observed between the sex- and age-groups. In contrast, in autumn juvenile males arrived significantly later than the rest of the population. Significant differences in wing chord length were found between the four sex and age classes (adult male, adult female, juvenile male, juvenile female) both in spring and autumn. However, significant differences in body mass were found only in autumn. In spring, in both sexes, wing length and body mass changed significantly with date of arrival. Masked Shrike in spring were lighter than in autumn. The results suggest that migration over desert is energetically costly and Eilat is a very important staging place for migratory Masked Shrikes.     

Seasonal variation in lipid and fatty acid composition of ice algae from the Barents Sea

The fatty acid compositions of neutral lipid, glycolipid and phospholipid fractions from ice algae sampled from the Barents Sea in spring and autumn were examined for seasonal differences. The ice-algal assemblages were dominated by diatoms. In spring, Nitzschia frigida was the most common species whereas resting stages of Thalassiosira bioculata and Actinocyclus cf curvatulus predominated in autumn. With the exception of one spring sample, neutral lipids predominated over glycolipids and phospholipids in all algal samples. The lipid fractions displayed characteristic fatty acid compositions. In the spring samples the major fatty acids of the neutral lipid fraction were 16:0, 16:1(n-7) and 20:5(n-3) whilst the glycolipid fraction was characterised by higher levels of 20:5(n-3) and C16 polyunsaturated fatty acids, particularly 16:4(n-1). Phospholipids contained higher levels of 22:6(n-3) than the other two lipid fractions although 20:5(n-3) was still the major polyunsaturated fatty acid. In the autumn samples, the neutral lipid fraction contained higher proportions of saturated fatty acids and 16:1(n-7) than the two polar lipid fractions and 22:6(n-3) was most abundant in phospholipids. As with the spring samples, 20:5(n-3) was the major polyunsaturated fatty acid in all lipid fractions of the autumn algae. Overall, the fatty acid compositions of the lipid fractions from spring and autumn algal samples were similar and are consistent with diatoms being the predominant group in the ice algae studied. The high level of neutral lipids observed in both spring and autumn samples suggests that the production of neutral lipids is characteristic of ice algae regardless of season. Nevertheless, some species-specific differences in lipid production may exist since the neutral lipid content of autumn samples containing mainly A. curvatulus was substantially higher than those in which T. bioculata predominated. Received: 26 September 1997 / Accepted: 12 January 1998     

The effect of microhabitats on the leaf litter decomposition and on the distribution of soil animals

Earthworm burrows as microhabitats for other soil fauna were studied in a hornbeam-oak mixed forest in Hungary. Comparative chemical analysis and feeding experiments were carried out to find out whether the leaves in the burrows of large-bodied earthworms are more decomposed than those from the surrounding areas. The total organic matter content, the C/N ratio, the stability coefficient and the percentage of tannins and lipids indicate that the chemical breakdown of the litter material is more advanced in the burrows than on the other parts of the forest floor especially in autumn. No consistent differences were observed in the amounts of other organic components. Feeding experiments showed that three species of the fauna preferred the leaves pulled into the burrows to those from the surrounding areas and the preference was greater in autumn than in spring.
It is suggested that the high density of some soil animals in the burrows in autumn is due to the more palatable food there; in summer the microclimate of the burrows is favoured, whereas spring can be considered as a transition period.     

Seasonally Dependent Effect of Ectopic Pituitary Grafts on 24-Hour Rhythms in Serum Prolactin and Gonadotropins in Rats

To assess to what extent the presence of an ectopic pituitary differentially affected circulating prolactin (PRL) and gonadotropin levels at different times of the year, rats kept under 12h light, 12h dark (12:12 LD) photoperi-ods and receiving a pituitary graft or a sham operation in summer or winter were examined 3 months later. In both male and female sham-operated rats, a circadian variation in serum PRL levels was found, with an acrophase varying from 21:53h to 00:54h and the mesor and amplitude higher in spring than autumn in males and higher in autumn than in spring in females. After grafting a pituitary, changes in serum PRL related to time of day were no longer observed. In pituitary-grafted male rats killed during spring, serum PRL levels were higher than controls at only a few time points throughout the 24h cycle, whereas in rats killed during autumn, there were no significant differences in PRL levels between grafted and control rats. Pituitary-grafted female rats killed during spring showed serum PRL levels significantly higher than those of sham-operated rats, while in female rats killed in autumn, PRL levels of pituitary-grafted and sham-operated rats did not differ. Significant variations of luteinizing hormone (LH) related to time of day were found in sham-operated male rats only, with acrophases at 23:52h and 00:24h for spring and autumn, respectively, and the mesor and amplitude of the rhythm significantly higher in autumn. Pituitary transplants suppressed 24h variations in circulating LH and depressed its levels during the two seasons examined. As far as follicle-stimulating hormone (FSH), pituitary grafts decreased circulating levels, with the extent of decrease higher during autumn than in spring. The results indicate that some endocrine consequences of the grafting of an ectopic pituitary are dependent on time of year.     

Seasonally Dependent Effect of Ectopic Pituitary Grafts on 24-Hour Rhythms in Serum Prolactin and Gonadotropins in Rats

To assess to what extent the presence of an ectopic pituitary differentially affected circulating prolactin (PRL) and gonadotropin levels at different times of the year, rats kept under 12h light, 12h dark (12:12 LD) photoperi-ods and receiving a pituitary graft or a sham operation in summer or winter were examined 3 months later. In both male and female sham-operated rats, a circadian variation in serum PRL levels was found, with an acrophase varying from 21:53h to 00:54h and the mesor and amplitude higher in spring than autumn in males and higher in autumn than in spring in females. After grafting a pituitary, changes in serum PRL related to time of day were no longer observed. In pituitary-grafted male rats killed during spring, serum PRL levels were higher than controls at only a few time points throughout the 24h cycle, whereas in rats killed during autumn, there were no significant differences in PRL levels between grafted and control rats. Pituitary-grafted female rats killed during spring showed serum PRL levels significantly higher than those of sham-operated rats, while in female rats killed in autumn, PRL levels of pituitary-grafted and sham-operated rats did not differ. Significant variations of luteinizing hormone (LH) related to time of day were found in sham-operated male rats only, with acrophases at 23:52h and 00:24h for spring and autumn, respectively, and the mesor and amplitude of the rhythm significantly higher in autumn. Pituitary transplants suppressed 24h variations in circulating LH and depressed its levels during the two seasons examined. As far as follicle-stimulating hormone (FSH), pituitary grafts decreased circulating levels, with the extent of decrease higher during autumn than in spring. The results indicate that some endocrine consequences of the grafting of an ectopic pituitary are dependent on time of year.     

Correlation between the morpho-cytohistochemistry of the outer mantle epithelium of Anodonta cygnea with seasonal variations and following pollutant exposure

Seasonal and experimental conditions induce morphological and cytochemical variations in the outer mantle epithelium (OME) of the freshwater bivalve Anodonta cygnea, probably influencing the shell calcification mechanism. In this study, OME samples were taken from untreated animals in autumn, winter, spring and summer as well as from animals exposed to divalent metals (cadmium, chromium, lead, copper and zinc) and pesticides (setoxidim and dimethoate) and observed by light microscopy. The present results showed that OME cells have larger cell volumes and increased amounts of secreted macromolecules during spring and summer than in autumn and winter. This correlates with higher shell calcification rates in spring and summer and lower shell calcification rates in autumn and winter. The experiments showed that incubation with pollutants for 8 months dramatically reduced the cellular volume so that the density of cytoplasmic material appeared higher that in the control samples. The pronounced changes in OME cells suggest a significant decrease in secretory activity following exposure to toxic agents and this has implications for the shell calcification process.     

Immunohistochemical evidence for the overexpression of protein kinase C in proliferative diseases of human thyroid.

We report immunohistochemical evidence for the overexpression of protein kinase C in various proliferative diseases of human thyroid. Immunohistochemical characterization of various surgically removed thyroid tissues, viz., cancer tissues: papillary carcinoma and follicular carcinoma; adenoma tissues: tubular, trabecular and colloid adenomas; adenomatous goiter; and normal thyroid was done using the monospecific monoclonal antibodies MC-1a, MC-2a and MC-3a, each of which is specific for types I, II and III isozymes of protein kinase C, respectively. For protein kinase C type II, a remarkable difference in staining intensity was noted between the cancerous and normal tissues. The cytoplasm of papillary and follicular carcinoma cells stained more intensely than that of normal thyroid cells. In the benign tumor and adenomatous goiter tissues, stronger staining was noted in the papilliform-proliferating portion and cubic epithelial cells. In the normal thyroid tissues, epithelial cells of greater height were more strongly stained than simple squamous epithelial cells. These results indicated that protein kinase C type II isozyme is expressed in larger amounts in cancerous and proliferative tissues of the human thyroid.