Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Aquaporins: water channel proteins of the cell membrane

Aquaporins (AQP) are integral membrane proteins that serve as channels in the transfer of water, and in some cases, small solutes across the membrane. They are conserved in bacteria, plants, and animals. Structural analyses of the molecules have revealed the presence of a pore in the center of each aquaporin molecule. In mammalian cells, more than 10 isoforms (AQP0-AQP10) have been identified so far. They are differentially expressed in many types of cells and tissues in the body. AQP0 is abundant in the lens. AQP1 is found in the blood vessels, kidney proximal tubules, eye, and ear. AQP2 is expressed in the kidney collecting ducts, where it shuttles between the intracellular storage sites and the plasma membrane under the control of antidiuretic hormone (ADH). Mutations of AQP2 result in diabetes insipidus. AQP3 is present in the kidney collecting ducts, epidermis, urinary, respiratory, and digestive tracts. AQP3 in organs other than the kidney may be involved in the supply of water to them. AQP4 is present in the brain astrocytes, eye, ear, skeletal muscle, stomach parietal cells, and kidney collecting ducts. AQP5 is in the secretory cells such as salivary, lacrimal, and sweat glands. AQP5 is also expressed in the ear and eye. AQP6 is localized intracellular vesicles in the kidney collecting duct cells. AQP7 is expressed in the adipocytes, testis, and kidney. AQP8 is expressed in the kidney, testis, and liver. AQP9 is present in the liver and leukocytes. AQP10 is expressed in the intestine. The diverse and characteristic distribution of aquaporins in the body suggests their important and specific roles in each organ.     

The effects of artificial enrichment upon the planktonic and benthic communities in a mesotrophic to hypertrophic loch series in lowland Scotland

Phytoplankton, submerged macrophytes, zoobenthos and zooplankton communities were studied concurrently in three lochs which progressively increased in trophic state. The phytoplankton showed a change in dominance from Bacillariophyceae (Pennales) and Desmidaceae in the mesotrophic Loch of the Lowes to Bacillariophyceae (Pennales) and Cyanobacteria in eutrophic Balgavies Loch and to Bacillariophyceae (Centrales) and Chlorophyceae in hypertrophic Forfar Loch. The Nygaard Compound phytoplankton quotient rose from 1.2 in the Lowes to 12 in Forfar. There was a decrease in number of species of submerged macrophytes, and in depth of colonisation from 5 m in the Lowes to 2 m in Forfar which was proportional to the decrease in mean transparency. Macrophyte biomass, however, increased in proportion to the concentration of total phosphorus in the lochs. There was a decrease in species of littoral zoobenthos, but an increase in density of profundal benthos from the Lowes to Forfar. Zooplankton also showed an increase in density with enrichment, accompanied by changes in dominance. Calanoida were dominant in the Lowes; Cladocera in Balgavies and Cyclopoda in Forfar. The importance of these differences in understanding the effects of progressive enrichment and to the management of the lochs is discussed.     

Meta-analytical study of productive and nutritional interactions of mycotoxins in growing pigs

A meta-analysis was carried out in order to study the association of mycotoxins with performance and organ weights in growing pigs. A total of 85 articles published between 1968 and 2010 were used, totaling 1012 treatments and 13 196 animals. The meta-analysis followed three sequential analyses: graphical, correlation and variance–covariance. The presence of mycotoxins in diets was seen to reduce the feed intake by 18% and the weight gain in 21% compared with the control group. Deoxynivalenol and aflatoxins were the mycotoxins with the greatest impact on the feed intake and growth of pigs, reducing by 26% and 16% in the feed intake and by 26% and 22% in the weight gain. The mycotoxin concentration in diets and the animal age at challenge were the variables that more improved the coefficient of determination in equations for estimating the effect of mycotoxins on weight gain. The mycotoxin effect on growth proved to be greater in younger animals. In addition, the residual analysis showed that the greater part of the variation in weight gain was explained by the variation in feed intake (87%). The protein and methionine levels in diets could influence the feed intake and the weight gain in challenged animals. The weight gain in challenged pigs showed a positive correlation with the methionine level in diets (0.68). The mycotoxin effect on growth was greater in males compared with the effect on females. The reduction in weight gain was of 15% in the female group and 19% in the male group. Mycotoxin presence in pig diets has interfered in the relative weight of the liver, the kidneys and the heart. Mycotoxins have an influence on performance and organ weight in pigs. However, the magnitude of the effects varies with the type and concentration of mycotoxin, sex and the animal age, as well as nutritional factors.     

Effect of pollution on phytoplankton in the Ashar Canal,a highly polluted canal of the Shatt al-Arab Estuary at Basrah,Iraq

The effect of pollution on the phytoplankton in the Ashar Canal was studied during March and June 1976. Higher temperatures were recorded in June. The canal water was more turbid than that of the adjoining Shatt al-Arab estuary due to high algal populations and sewage disposal. The chlorosity values were remarkably high in the canal, due to sewage disposal. The flood waters in June lowered the chlorosity in both estuary and canal. Sewage disposal into the canal decreased its dissolved oxygen content. The lower oxygen values in the estuary in June were accompanied with higher temperatures. The pH values were generally higher in the estuary and were also higher in June than in March.Eighty-six algal taxa were recorded, 45 of which were diatoms. The phytoplankton in the estuary was more abundant in March, due to the increase in currents and turbidity in June. The Chlorophyta, Conjugatophyta, Myxophyta and Bacillariophyta in the estuary showed reverse seasonal trends from those of the total phytoplankton. These algal seemed to flourish during periods of high temperatures. The dense blue-green algae recorded in June is attributed to the high temperature and dissolved organic matter. The Chrysophyta recorded high populations in the estuary in March and were totally absent in June. Lower temperatures and high transparency in March might have led to their relative abundance.The total phytoplankton in the Ashar Canal followed two different seasonal trends, one resembling and the other differing from those in the estuary. The disposal of domestic sewage and agricultural wastes in the canal seemed to lead to such adverse seasonal variations. The diatoms only dominated the phytoplankton at one station in both months. The sewage and agricultural wastes disposal seemed to favour the abundance of the other phyla than the diatoms. Increased organic load in the canal has led to a considerable increase in the Myxophyta in June. Blooms of Chlamydomonas sp. and Euglena acus increased the phytoplankton densities in March at stations II and IV, respectively. Benthic or periphytic algae were found in the phytoplankton populations. Raised salinity seemed to restrict the distribution of the planktonic diatom Bacillaria paradoxa. Among the noticeable widespread planktonic algae in the study area are Dinobryon sertularia, Pediastrum duplex and P. simplex.     

Effect of alternating magnetic field on the composition and level of lipids in radish seedlings

The effects of alternating magnetic field (AMF) with the frequency of 50 Hz on the dynamics of unfolding of cotyledon leaves, the composition and level of polar and neutral lipids and their component fatty acids (FA) were studied in 5-day-old radish seedlings (Raphanus sativus L. var. radicula D.L., cv. Rozovo-krasnyi s belym konchikom) grown in the light and in the dark. AMF weakened the inhibitory effect of light on unfolding of cotyledon leaves. In the light, the total content of lipids, as well as the level of polar and neutral lipids, in the seedlings in AMF was greater than in control material. In polar lipids, the total amount of glyco-and phospholipids increased; in neutral lipids, the level of triacylglycerols rose. The ratio between phospholipids and sterols (PhL/S) increased. In the dark, the total content of lipids and the level of neutral lipids in the seedlings in AMF were lower than in control material, and the ratio PhL/S decreased. In control material, there were no differences in the relative total content of unsaturated FA in the light and in the dark, whereas the level of linolenic acid was higher in the light than in the dark. AMF induced a decrease in the content of linolenic acid in the light and a rise in the dark; the level of erucic acid in the light decreased. The ratio between unsaturated and saturated FA decreased both in the light and in the dark. It was concluded that AMF with the frequency of 50 Hz was an adjusting agent considerably changing the content of lipids in the radish seedlings in the light and in the dark.     

Nitrification and seasonal changes in bacterial populations in the rhizosphere ofSuaeda andArthrocnemum species growing in saline soils

Summary The nitrification rate in the rhizosphere of Suaeda and Arthrocnemum plants growing in saline soils, as affected by microbial populations, temperature, pH, and organic matter, was examined in the field throughout the year. The genera Nitrosomonas and Nitrobacter were most common in the rhizosphere soil. The bacterial counts in the rhizosphere of both plants fluctuated during the study period, reaching peak values during February–March and in August. The nitrate concentration in the rhizosphere soil could be related with the observed increase in the numbers of ammonium-oxidizers and nitrite-oxidizers in the latter part of the study period. The pH of the rhizosphere soils did not have any influence on the nitrification rate at the values measured. The rhizosphere organic content varied between 1.8 and 4% (w/w), showing the continuous availability of organic matter in the soil. The seasonal changes in bacterial populations in the rhizospheres of both plants was described as the result of the combination of several factors.     

Feral sheep and cattle and royal albatrosses on Campbell Island; population trends and habitat changes

Abstract

Sheep farming on Campbell Island began in 1895 and ended in 1931. The sheep population peaked at 8500 in 1910; only 1000 feral sheep were counted in 1961, but by 1969 there were 3000. The island was divided with a fence in 1970 and the sheep on the northern half were shot. Sheep continued to increase south of the fence, from 2088 in 1969 to 2521 in 1971 and, after a decline to 2400 in 1976, to 2861 in 1977. Breeding pairs of royal albatrosses numbered 2278 in 1958, 4344 in 1969, 5336 in 1976, and 4906 in 1977 - the first time the breeding population of this normally biennial breeder had been counted in two consecutive years. The number of feral cattle decreased from 20 in 1971 to 11 in 1977. These population trends are discussed in the context of changes to the flora in grazed and stock-free areas.     

CARBOHYDRASES IN THE DIGESTIVE SYSTEM OF THE SPINED SOLDIER BUG,Podisus maculiventris (SAY) (HEMIPTERA: PENTATOMIDAE)

The spined soldier bug, Podisus maculiventris, is a generalist predator of insects and has been used in biological control. However, information on the digestion of food in this insect is lacking. Therefore, we have studied the digestive system in P. maculiventris, and further characterized carbohydrases in the digestive tract. The midgut of all developmental stages was composed of anterior, median, and posterior regions. The volumes of the anterior midgut decreased and the median midgut increased in older instars and adults, suggesting a more important role of the median midgut in food digestion. However, carbohydrase activities were predominant in the anterior midgut. In comparing the specific activity of carbohydrases, α‐amylase activity was more in the salivary glands (with two distinct activity bands in zymograms), and glucosidase and galactosidase activities were more in the midgut. Salivary α‐amylases were detected in the prey hemolymph, demonstrating the role of these enzymes in extra‐oral digestion. However, the catalytic efficiency of midgut α‐amylase activity was approximately twofold more than that of the salivary gland enzymes, and was more efficient in digesting soluble starch than glycogen. Midgut α‐amylases were developmentally regulated, as one isoform was found in first instar compared to three isoforms in fifth instar nymphs. Starvation significantly affected carbohydrase activities in the midgut, and acarbose inhibited α‐amylases from both the salivary glands and midgut in vitro and in vivo. The structural diversity and developmental regulation of carbohydrases in the digestive system of P. maculiventris demonstrate the importance of these enzymes in extra‐oral and intra‐tract digestion, and may explain the capability of the hemipteran to utilize diverse food sources.     

Histological comparison between wheat embryos developing in vitro from isolated zygotes and those developing in vivo

There is currently great interest shown in understanding the process of embryogenesis and, due to the relative inaccessibility of these structures in planta, extended studies are carried out in various in vitro systems. The culture of isolated zygotes in particular provides an excellent platform to study the process of in planta embryogenesis. However, very few comparisons have been made between zygotic embryos grown entirely in cultures and those grown in vivo. The present study analyses the differences and similarities between the in vitro and in vivo development of wheat zygotic embryos at the level of morphology and histology. The study was possible thanks to an efficient culture system and an appropriate method of preparing isolated wheat zygotes for microscopy. The in vitro embryos were fixed, embedded and sectioned in the two-celled, globular, club-shaped and fully differentiated stages. Embryos developing in vitro closely followed the morphology of their in planta counterparts and their cell types and tissues were also similar, demonstrating the applicability of the present culture system for studying the process of zygotic embryogenesis. However, some important differences were also detected in the case of in vitro development: the disturbance of or lack of initial polarity led to changes in the division symmetry of the zygotes and subsequently to the formation of uniform cells in the globular structures. Presumably, differences between the in vitro and in planta environments resulted in a lower level of differentiation and maturation in in vitro embryos and in abundant starch and protein accumulation in the scutellum.     

Carbohydrate metabolism in Musa paradisiaca

Considerable variations exist in the content of glucose, fructose, sucrose, starch and protein and in the activities of enzymes involved in carbohydrate metabolism between different parts of the banana plant (Musa paradisiaca). Sucrose synthetase is present in the highest concentration in rootstock and fruit pulp, and sucrose phosphate synthetase in the pseudostem. The highest ratio of the activity of sucrose phosphate synthetase to sucrose synthetase is found in leaves. Acid invertase is present in leaves, leaf-sheath and fruit pulp and is not demonstrable in rootstock and pseudostem. Neutral invertase activity is high in pseudostem and leaf-sheath. Starch phosphorylase is largely concentrated in fruit pulp and rootstock. The maximum activity of ATP:d-phosphoglucose (ADPG) pyrophosphorylase is found in rootstock. β-Amylase is not demonstrable in rootstock and is largely concentrated in leaf-sheath. Hexokinase is most active in rootstock and the lowest in leaves. Acid phosphatase and alkaline phosphatase activity is highest in fruit pulp and pseudostem. Glucosephosphate isomerase is most active in the rootstock and lowest in the leaves.     

Histopathological lesions of molluscs in the harbour of Norderney,Lower Saxony,North Sea (Germany)

During a combined research project at several stations along the Lower Saxony coast (German North Sea) antifouling biocides were analysed in water, sediment and biota. Pathological alterations in blue mussel, Pacific oyster and periwinkle found in the harbour of Norderney and a reference station are presented here and discussed on the background of chemical analyses. The molluscan species from the reference station Borkum East flat did not show any pathological effects in central organs, except those provoked by an infestation in the gastro-intestinal tract by the copepod Mytilicola intestinalis and trematode larvae. In most animals, the metacercaria were found in the interstitial tissue without any inflammatory reaction. In a minor number of specimens, an inflammatory reaction in the mucosa and sub-mucosa of the intestine occurred in association with Mytilicola infestation. These reactions may be evoked through mechanical irritation of the gut epithelium, metabolic products of the parasites or invading bacteria. In contrast to the observed pathological changes of mussels, oysters and periwinkles in Norderney harbour were not found to be associated with parasitic infestation. The most prominent pathological alterations were observed in the digestive system and in the gonad. In the gastro-intestinal tract inflammatory reactions, atrophy and necrosis of tubules in the mid gut gland were most pronounced in spring at the beginning of the pleasure boat season in the Pacific oyster and to a minor degree in the blue mussel and the periwinkle. The latter displayed additional inflammatory and necrotic processes in the gills. Especially in the gonad, an elevated resorption rate of gametes was present in the Pacific oyster and in the periwinkle. In addition, impact of organotin compounds was reflected in an intersex index of up to 1.4 in Littorina littorea in coincidence with masculinization of the reproductive organs.     

The Effects of NaCl Treatment on Water Relations, Growth, and ABA Content in Barley Cultivars Differing in Drought Tolerance

Changes in transpiration and stomatal conductance and other characteristics of water relations, growth rate, and ABA content have been followed in short- and long-term experiments in two barley cultivars (cv. Michaelovsky and cv. Prairie) with contrasting drought resistance characteristics. The aim of this work was to reveal the importance of stomatal behavior in salt tolerance and also the involvement of ABA in its control. Salinity stress brought about a reduction in stomatal conductance in both cultivars, but the effect was initially more pronounced in the drought-tolerant cv. Prairie than in the drought-sensitive cv. Michaelovsky. The difference between the two cultivars changed with time, and later on transpiration and stomatal conductance became higher in Prairie than in Michaelovsky. In both the short and the long term, the extent of stomatal closure due to salinity correlated with the level of ABA accumulation in the leaves of the plants. Fast stomatal closure was likely to be responsible for growth resumption after an initial arrest by salt treatment and for the maintenance of extension growth later on, thus enabling its higher rate in Prairie than in Michaelovsky plants. Leaves of Prairie accumulated less toxic chloride ions, which may be the result of a lower transpiration rate observed during the first phase of salt treatment. A subsequent increase in stomatal conductance observed in Prairie is likely to ameliorate their gas exchange and maintain photosynthesis and growth. Thus, differences between the cultivars in the stomatal response to salinity changed with time, which may be why there are discrepancies in the attempts to relate stomatal conductance to salt tolerance observed in literature.     

The role of vole populations in prevalence of the parasite (Echinococcus multilocularis) in foxes

Effects of population fluctuation of the gray-sided vole(Clethrionomys rufocanus) on the prevalence (infection rates) of the parasiteEchinococcus multilocularis in red fox(Vulpes vulpes) populations was investigated from 1985 to 1992 in eastern Hokkaido (Abashiri, Nemuro, and Kushiro area), Japan. This parasite needs two hosts to complete its life cycle; the gray-sided vole as its intermediate host and the red fox as its final host. We found that: (1) Infection rates in foxes depended on the current-year abundance of voles in all three study areas, particularly in Abashiri. (2) In addition to this direct density-dependence, delayed density-dependence between the infection rate and the prior-year abundance of voles was detected in Nemuro and in Kushiro. (3) The regional differences in density-dependence pattern were related to regional differences in the winter food habits of red foxes: in Abashiri the proportion of voles in the fox’s diet greatly decreases in winter, while the proportion remains high in winter in Nemuro and in Kushiro, probably because of shallower snowpack. These results suggest that infection rates in foxes in Abashiri were less influenced by the prior-year prevalence, since the infection cycle might be interrupted in winter, when voles became less important in fox’s diet. In contrast, the state of the prevalence may carry over from year to year in Nemuro and in Kushiro, because red foxes continue to eat a considerable amount of voles throughout year. The regionally contrasted results for the relationship between infection rate in foxes and vole abundance were parallel to the regional difference in fluctuation pattern of vole populations, which are highly variable in Abashiri area, but less variable in Kushiro-Nemuro area. Drastic change in vole populations appears to affect the host-parasite system.     

A role for ecdysteroids in the phase polymorphism of the desert locust

Abstract. Locusts show density-dependent continuous phase polymorphism; they appear in two forms or phases, gregarious and solitary, and there is a continuous range of intermediates between the extreme phases. Although earlier studies showed that there are no major phase-dependent differences in the titres of ecdysteroid in the haemolymph of desert locusts, Schistocerca gregaria , recent studies showed some minor differences in the timing of the main peak of ecdysteroids. In crowded penultimate- and last-instar hoppers, peak titres were lower but longer-lasting, whereas in isolated hoppers they were higher but of shorter duration. The major component of the haemolymph peak of ecdysteroid was 20-hydroxyecdysone in both isolated and crowded hoppers, but differences were found in the relative amounts of two minor components (makisterone A-like compound and highly polar products). In S. gregaria adults, the regression of the prothoracic glands was irregular and subject to high individual variations, but phase-dependent differences in the rate of regression were significant, and the adult glands did not produce physiologically significant amounts of ecdysteroids. Peak titres of ecdysteroid in the haemolymph were higher in isolated than in crowded adults. Similar to larvae, adults of the solitary phase contain more ecdysone in the haemolymph than those of the gregarious phase. Moreover, the phase characteristic titres of ecdysteroid in the adult stage can be shifted from one phase to another phase in response to appropriate changes in density. In contrast, the maximum amount of ecdysteroids in both ovaries and eggs was significantly higher in the gregarious than in the solitary phase. The amounts, and to some extent the types of ecdysteroids, were the only difference between ovaries and eggs from solitary and gregarious locusts. In addition, in newly hatched larvae, the amount of ecdysteroid was more than five times higher in gregarious than in solitary phase.     

Chlorophyll distribution in the stems and trunk of beech trees

The distribution of chlorophyll was examined in cross-sections of 2- and 6-year-old stems as well as in the bark of the stump trunk of beech trees, utilising chlorophyll autofluorescence. The investigations were conducted using a confocal microscope. The tests carried out on 2 – 6-year old stems showed a large presence of chlorophyll in the bark, in primary and secondary rays as well as in the pith, but smaller amounts in wood parenchyma cells. There was no chlorophyll in the cork, sclerenchyma: in wood in vessels, tracheids and fibers. A reduction in the chlorophyll content in 6-year-old stems was not observed. In the bark of the trunk, chlorophyll was found in large amounts directly under the cork and in vestigial amounts in the primary phloem.     

Hypothalamic metabolism of neurotransmitters (serotonin,norepinephrine, dopamine) and NPY,and gonadal and adrenal activities,during the early postnatal period in the rat

It is noteworthy that in the rat the early postnatal life is marked by an activation of both the corticostimulating function of the adenohypophysis in neonates of both sexes and of the gonadostimulating function mainly in males. In order to specify if such neuroendocrine variations are temporally correlated with changes in the hypothalamic metabolism of neurotransmitters, the hypothalamic metabolism of serotonin (5 HT), norepinephrine (NE), and dopamine (DA) and the hypothalamic content of neuropeptide Y (NPY) have been investigated in newborn rats of both sexes, delivered at term by cesarean section, as well as changes in the activity of both the hypothalamo-pituitary adrenal axis (HPA) and the hypothalamo-pituitary gonadal axis (HPG). Experimental data suggested that 1) in males a rise in hypothalamic metabolism of 5 HT, NE and DA occurs during the first two hours after delivery, whereas in females, only the metabolism of NE increases. Moreover, the postnatal metabolism of NE was higher in females than in littermate males; 2) NPY content of the hypothalamus, which was at birth significantly higher in males than in females, dropped in the former but not in the latter; 3) in newborn males, an early surge of plasma testosterone occurs, suggesting postnatal activation of the HPG axis; on the other hand, in females, a late and slight increase in plasma estradiol is observed; 4) in early postnatal life, a sex-independent rise in plasma ACTH and adrenal and plasma corticosterone levels suggest a comparable activation of the HPA axis in newborns of both sexes. In conclusion, the early postnatal activation of the corticostimulating function in neonates of both sexes and that of the gonadostimulating function, mainly in males, could be temporally correlated with a rise in the hypothalamic metabolism of two neurotransmitters, 5 HT and NE, and of NPY content. According to our data, a sex-dependent metabolsim of neurotransmitters in the hypothalamus is already apparent in early postnatal life.     

Diurnal and seasonal fluctuations in wood ant (Formica polyctena) nest temperature in two geographically distant populations along a south – north gradient

Temperature changes were recorded continuously in eleven nests of Formica polyctena located in Southern Finland and the Czech Republic. Nest temperatures were recorded in the Czech site from 2003 to 2005 and in Finland during 2004 – 2005. Seasonal changes in nest temperature were very similar in both locations. During summer, the ants maintained a relatively high and constant temperature in their nest in both locations. Summer nest temperatures in Finland were higher than those in Czech during 2004 –2005 but did not differ from those in Czech during 2003– 2004. This indicated that the geographical differences were less important than difference between seasons. Nest temperature peaked in June. During summer, daily temperature fluctuations were significantly lower in Finland than in Czechia probably due to shorter nights in Finland. Apparent differences in daily temperature patterns were found in nests with different moisture in both locations. In dry nests, temperature peaked in the evening and decreased overnight, whereas the apparent increase was delayed to the night in wet nests. The spring increase in temperature in wet nests was much steeper that that in the dry ones when whole spring period is considered. During one day, temperatures fluctuated much more in dry nests than in wet ones. These differences seem to be caused by differences in thermal capacity between dry and wet nests. Received 24 July 2006; revised 19 February 2007; accepted 19 May 2007.     

Seasonal changes in intra- and interorgan occurrence of rodlet cells in freshwater bream

Significant seasonal differences in intra- and interorgan prevalence, abundance and distribution of rodlet cells (RC) were observed in freshwater bream caught in May and August 1997 from a PCB-polluted lake, Lake Kernaala, Finland. In May, the majority of RCs in liver were seen in blood vessel endothelium, while in August most cells were located in the epithelium of the intrahepatic biliary ducts. In kidney, a significant increase in RCs in the columnar epithelium of the collecting ducts was observed from May to August. RCs in spleen were extremely rare in May, but were seen frequently in the endothelium of the splenic blood vessels in August. In gill and intestine, RCs were found in every tissue sample studied, with no statistical differences in their abundance or distribution between seasons. No RCs were seen in gonads. Total numbers of RCs increased dramatically from May to August in kidney and in spleen. The frequency of RCs corresponded strongly with the current phase of parasitic infections in liver, kidney, and spleen. It is concluded that RCs play a role in host defence mechanisms in fish, displaying induced expression at the times of peak parasitic prevalences.     

Sex differences in otoacoustic emissions measured in rhesus monkeys (Macaca mulatta)

Click-evoked otoacoustic emissions (CEOAEs) and distortion-product OAEs (DPOAEs) were measured in about 60 rhesus monkeys. CEOAE strength was substantially greater in females than in males, just as in humans. DPOAE strength was generally slightly stronger in females, just as in humans. In males, CEOAEs were weaker (more masculine) in the fall breeding season and in winter than in the summer. In females, CEOAEs were slightly stronger (more feminine) in the fall, when sex steroids are elevated in females (and males), than in the summer when rhesus monkeys are reproductively quiescent. Thus, the sex differences in CEOAEs were greater in the fall than in the summer. We presume that the seasonal fluctuations in OAEs reflect activational hormonal effects, while the basic sex differences in OAEs likely reflect organizational effects of prenatal androgen exposure. Some monkeys of both sexes had been treated with additional testosterone or the anti-androgen flutamide during prenatal development. In accord with expectations, prenatal androgen treatment weakened CEOAEs in females, and prenatal flutamide treatment strengthened CEOAEs in males. For DPOAEs, the differences between treated and untreated groups were mostly small and often inconsistent. Taken as a whole, the data from both rhesus monkeys and humans suggest that the linear, reflection-based mechanism of OAE production that underlies CEOAEs is more sensitive to prenatal androgenic processes than is the nonlinear distortion mechanism that underlies DPOAEs.