The use of PIT telemetry to study movements of ammocoetes and metamorphosing sea lampreys in river beds

Passive integrated transponder (PIT) tags were surgically implanted in 118 sea lamprey Petromyzon marinus ammocoetes which were left to recover in the laboratory for 2 months. During this period 55 individuals started to metamorphose. In the late summer of 2002 the tagged animals were released in a small tributary of the River Mondego, Portugal, and were regularly monitored for a period of 2 months using a portable PIT tag reader. The distribution of the released animals changed from an initial uniform pattern to a random distribution, and then to an aggregated pattern. At the end of the first week 60% of the tagged sea lampreys had already left the study area, indicating their dynamic behaviour. Ammocoetes were more active than metamorphosing sea lampreys, and downstream movements were more frequent when compared to the upstream ones, which were usually a short distance. In order to determine the influence of the dark‐light cycle in the diel activity rhythms, 10 tagged sea lamprey ammocoetes were released in a tank (2000 l capacity) and their position monitored twice a day, for a period of 1 month. Ammocoetes locomotor activity appeared to be conditioned by circadian rhythms, and they were particularly active during darkness.     

A survey of angiosperm species to detect hypodermal Gasparian bands. II. Roots with a multiseriate hypodermis or epidermis

PETERSON, C. A. & PERUMALLA, C. J., 1990. A survey of angiosperm species to detect hypodermal Casparian bands. II. Roots with a multiseriate hypodermis or epidermis.
Roots of 25 species which had either a multiseriate hypodermis or a multiseriate epidermis were tested for the presence of a hypodermal Casparian band. All species save one were in the Liliopsida and six were orchids with both soil and aerial roots. Lignosuberized hypodermal Casparian bands were present in all species tested; those with a biseriate hypodermis had bands in both layers and of those with a multiseriate hypodermis, the three species which were tested had bands in every layer. Although Casparian bands can often be recognized by the presence of sinuous walls in longitudinal views of uniseriate hypodermal layers, these sinuosities were not evident in multiseriate hypodermal layers containing Casparian bands. The lack of air spaces, once thought to be a characteristic feature of the hypodermis, did not hold true for some members of the Liliopsida. All walls of the hypodermis were suberized, indicating that suberin lamellae were probably present in addition to Casparian bands. We recommend using the term 'exodermis' to refer to a hypodermis which has a Casparian band. Epidermal walls of non-orchid roots were suberized whereas those of orchids were lignified. Regardless of their type of modification, all epidermal walls were permeable to the apoplastic dye, Cellufluor.     

Microsurgery on bovine embryos at the morula stage to produce monozygotic twin calves

Mature Brangus donor cows were superovulated with follicle stim-ulating hormone administered twice daily in intramuscular injections. On day 6.5 to 7 post-estrus, embryos were collected non-surgically using a phosphate-buffered saline medium. A total of 37 ova was collected, of which 28 were advanced morulae and early blastocysts. Twenty of these embryos were selected for micromanipulation with a radial-type Leitz micromanipulator. While the embryos were in a holding medium containing 10% fetal calf serum, three glass microinstruments were used to open the zona pellucida, remove the mass of blastomeres and bisect the embryo on a vertical plane. Halved embryos were inserted into bovine zonae and placed either as single half-embryos or twin half-embryos in 0.25 ml French straws with fresh holding medium. The micromanipulated embryos (demi-embryos) were then non-surgically transplanted, either as a single demi-embryo or as a twin demi-embryo pair, into the uterine horn of day 6.5 to 8 recipient beef females ipsilateral to the existing corpus luteum. Of the 14 micromanipulated embryos that were transplanted to recipients, pregnancy rates were 16.6% for the single demi-embryos and 62.5% for the twin demi-embryos. No pregnancies resulted from bisected blastocysts.     

An Australian trial of ThinPrep: a new cytopreparatory technique

To evaluate the sensitivity and suitability of ThinPrep, a new slide preparation technique, 2026 paired cervical cytology slides were examined. After conventional Papanicolaou smears were prepared, the sampling instruments were rinsed in a fluid fixative. ThinPrep slides were then prepared in the laboratory from the surplus cells in the fixative. Compared with the Pap smears, ThinPrep slides were easier and quicker to screen, were inconclusive less often, and had similar rates for detecting abnormalities and infection. There were more unsatisfactory ThinPrep slides and more ThinPrep slides lacked endocervical cells. Both of these shortcomings were found to be linked to the choice of sampling implements. This study, in which a variety of sampling instruments was used, fails to confirm some of the previous claims made for the new technique.     

Inviting trouble: Introduced pasture species in northern Australia

Abstract I surveyed the history of exotic pasture introductions in northern Australia to compare the rate of introduction of useful species with that of weeds. Between 1947 and 1985, 463 exotic grasses and legumes in at least 2033 accessions were intentionally introduced into the region, the grasses predominantly from Africa, and the legumes from Central and South America. Of these, only 21 (5%) came to be recommended as useful, while 60 (13%) became listed as weeds. Seventeen of the useful plants were in fact also weeds, leaving only 4 species (<1%) that were useful without causing weed problems. They were far outnumbered by the 43 species (9%) that were weeds but had no recorded use. Of the 60 weeds, 21 were weeds of cropping, 20 were weeds of conservation and 19 were weeds of both sectors. Thirteen were listed as major crop weeds. Growth rate, maximum height, seed size, and continent of origin were unrelated to weediness. Good predictors of weediness were whether a plant was useful, a good performer in trials, or persisted at a field site. In addition, grasses were more likely, and legumes less likely, to be weedy than expected. It is argued that a new form of assessment is required before an exotic plant species is released into the Australian environment as a pasture plant. This would recognize that a successful introduction is almost certain to become a weed in some situations, and would attempt to assess the net national benefit of the proposed introduction.     

Strain differences in three measures of ethanol intoxication in mice: the screen,dowel and grip strength tests

Mice from 8 to 21 inbred strains were tested for sensitivity to ethanol intoxication using a range of doses and three different measures: the screen test, the dowel test and a test of grip strength. Strains differed under nearly all conditions. For the dowel test, two dowel widths were employed, and mice were tested immediately or 30 min after ethanol. For the dowel and screen tests, low doses failed to affect some strains, and the highest doses failed to discriminate among mice, maximally affecting nearly all. For grip strength, a single ethanol dose was used, and mice of all strains were affected. Pharmacokinetic differences among strains were significant, but these could not account for strain differences in intoxication. For doses and test conditions in the middle range, there were only modest correlations among strain means within a test. In addition, genotypic correlations across tests were modest to quite low. These results suggest that different specific versions of a test reflect the influence of different genes, and that genetic influences on different tests were also distinct.     

Survival of small and large littermate blastocysts in swine after synchronous and asynchronous transfer procedures

Thirty-two crossbred sows were assigned to synchronous and asynchronous embryo transfer procedures to determine if, within a litter, small blastocysts were as viable as large blastocysts. Synchronous embryo transfers were established when donors and recipients displayed the onset of estrus (Day 0) within 6 h of each other. Asynchronous transfers were established when recipients displayed the onset of estrus 18 to 24 h after that of donors. An equal number (four or five) of the smallest and largest diameter blastocysts, from a Day 7 donor, were transferred to separate uterine horns of a Day 7 (synchronous) or a Day 6 (asynchronous) recipient. Each recipient's uterine horns were ligated at the external bifurcation to prevent transuterine embryonic migration. The percentage of blastocysts surviving was determined 300 h (12.5 d) after donors exhibited estrus. Small as well as large Day 7 blastocysts survived following asynchronos transfer to a Day 6 recipient. However, fewer (P<0.01) small blastocysts survived synchronous transfer than large blastocysts. These data suggested that small blastocysts were lost due to asynchrony with the uterine environment; however, when transferred to a less advanced environment, small blastocysts were equally viable as large blastocysts.     

The formation and execution of sequential plans in pigeons (Columba livia)

The ability to formulate and execute plans is a hallmark of human behaviour. Here we present evidence of planning in pigeons. Subjects were trained to respond to three geometric shapes in a prescribed order. Probe trials were then introduced in which, following a response to the first item, the on screen positions of the second and third item were exchanged. If subjects were planning a sequence of responses at the outset of a trial, we would expect reaction time to the second item to increase, reflecting the updating of a predetermined response plan. This is exactly what was found. Subjects also responded correctly on trials in which, following a response to the first item, stimuli were covered by opaque white squares. Together these results suggest pigeons are able to plan one step ahead on the simultaneous chaining paradigm.     

Influence of budget and reinforcement location on risk-sensitive preference

Little is known about the effect that procedural variables have on risk-sensitive preference. This study assessed the effect of procedural variables on pigeons' choice between a fixed and variable amount of reinforcement (amount risk) and, in a separate condition, between a fixed and variable delay until reinforcement (delay risk). Experiment 1 investigated the impact of water reinforcement and risk dimension when pigeons were in a restrictive budget, where access to water was less than that necessary to maintain current body weight, and a condition where the pigeons had ample access to water. Pigeons exhibited a greater tendency to prefer the variable alternative for delay risk than for amount risk in both restrictive and ample budgets. Varying water budget had no effect on risk preference. Experiment 2 investigated the influence of water reinforcer location while in a restrictive budget, in which reinforcers were delivered to a single location, two distinct locations, or a randomly selected location. With amount risk, pigeons were risk averse when reinforcers were delivered in separate or random locations and were indifferent to risk when delivered to a single location. With delay risk, pigeons were generally risk prone with no effect from reinforcement location. The finding that pigeons were risk averse when reinforcers were delivered to separate locations and were indifferent to risk when delivered to a single location offers a methodological explanation to the inconsistent findings in the literature with amount risk.     

Drinking tools of wild chimpanzees at Bossou

Use of drinking tools by wild chimpanzees (Pan troglodytes) and the context in which the tools were used were studied at Bossou, Republic of Guinea, West Africa. During the middle to late dry season and early wet season liquids are available occasionally in the holes of trees. Chimpanzees drank water or sap using a leaf (or fiber) as a sponge or spoon. When the chimpanzees were on the ground, they tended to use one of a few kinds of soft, hairless leaves, if they were available nearby. Females, particularly juveniles and adolescents, were thought to be the main users of the drinking tool. In a few episodes, a tool set was used to procure liquid. Once a chimpanzee used a stick to push a leaf sponge into a water hole and to pull it out from the hole. In addition, three chimpanzees used a pestle to squeeze sap from an oil-palm tree before using a fiber sponge. © 1995 Wiley-Liss, Inc.     

The interaction of the causative agent of melioidosis with the host's alveolar macrophages]

Studies were carried out on guinea pigs and albino rats, intranasally infected with P. pseudomallei C-141. The cells of bronchovesicular exudate were obtained from animals 1, 4 and 24 hours after infection. Electron microscopy was applied to study the process of interaction of the agent and alveolar macrophages. Bacteria were shown to form a capsule which permitted avoiding phagocytosis, when entering the host respiratory system. Microbes that failed to form a capsule were absorbed by macrophages and enclosed in a phagosome. Then some bacteria were destroyed by the lysosomal enzymes, the other synthesized a capsule, which protected them against the effect of phagolysosome content. There were also such microbes which escaped from a phagosome prior to fusion with lysosomes and parasitized in phagocytic cytoplasma forming a capsule there. By the end of the first 24 hours of observation the intact encapsulated microbe species were found to prevail in the host cells.     

老年急性脑梗死患者血清CRP, FG, LP(a)变化研究

目的:探讨老年急性脑梗死患者检测血清C反应蛋白(CRP)、纤维蛋白原(FG)及脂蛋白(a)(LP(a))的变化及意义。方法:选择2013年12月-2014年12月在我院就诊的年龄≥60岁的急性脑梗死患者90例作为实验组,根据中国脑卒中患者临床神经功能缺损程度评分标准(NDS),分为轻型、中型和重型;根据病灶直径及Adama分型法分为腔隙性脑梗死、小梗死和大梗死,另外选择90例健康老人为对照组。测定所有受试者血清中的CRP、FG及LP(a)的水平,并比较它们在实验组与对照组、实验组不同严重程度和不同病变类型的患者中的差异。结果:实验组血清CRP、FG和LP(a)的水平高于对照组,且差异具有统计学意义(P0.05);重型患者血清CRP、FG和LP(a)水平明显高于中型患者,中型患者显著高于轻型患者,且差异均有统计学意义(P0.05);大梗死患者血清CRP、FG和LP(a)水平明显高于小梗死患者,小梗死患者显著高于腔隙性梗死患者,且差异均有统计意义(P0.05)。结论:血清CRP、FG和LP(a)水平异常升高与老年急性脑梗死的发生发展密切相关。     

Changes in apoptotic rate and cell viability in three fish epidermis cultures after exposure to nonylphenol and to a wastewater sample containing low concentrations of nonylphenol

Three types of epidermal cultures of fish were used for toxicological investigations, a primary cell culture and a tissue culture prepared from the rainbow trout Oncorhynchus mykiss Walbaum and the cell line EPC, derived from a skin tumour of the carp Cyprinus carpio L. Two studies were carried out to compare the different culture systems. In the first cultures were incubated with nonylphenol and in the second set of experiments the cell cultures were exposed to a wastewater sample containing low concentrations of nonylphenol (NP). Both cell cultures were similarly sensitive to nonylphenol with respect to the endpoints cell viability (LC₅₀     

Morphological and electrophysiological changes produced by electrical stimulation in cultured neuroblastoma cells.

Electric fields, which were equivalent to those generated by medical devices, were applied to cultured neuroblastoma cells (mouse and human) to test for morphological damage and to establish damage thresholds. Each of two methods of applying fields permitted flow of electrical current and minimized exposure of cells to electrode-breakdown products. One method consisted of a pair of parallel wires in a Petri dish by which current was delivered within a fixed volume of flowing tissue-culture media. With the other method, the cells were held in a confined geometrical chamber and current was applied via agar bridges. Under a given set of stimulation parameters, damage was found to be variable from cell to cell. By changing the strength of the electric field (frequency and duration of stimulation held constant), thresholds of several V/cm were found above which cell damage could be reliably produced. Depending on the intensity of the field, damage took the form of cell lysis or damage to neurites. Intracellular recordings from the mouse neuroblastoma cells revealed a correlation between a decline in resting transmembrane potential and stimulus intensity. Human neuroblastoma cells were less susceptible to damage than were the mouse neuroblastoma cells, given the same strength of applied electric fields.     

The Sense of Effort and two Models of Single-Joint Motor Control

Two sets of experiments were carried out. In the first set, human subjects were asked to make the same effort with the elbow flexors at different joint angles under isometric conditions. In some experiments, the subjects were standing with the arm in a vertical (parasagittal) plane; in others, they were seated with the arm in a horizontal (transverse) plane. When muscular torque at a given effort level (ordinate) was plotted as a function of elbow joint angle (abscissa), the resulting isoeffort torque-angle profiles tended to be flat or negatively sloping over a range from 45° to 135°, and they were often nonmonotonic. Increases in effort up to near-maximal levels caused the isoeffort torque-angle profiles to shift upward with little alteration in shape. In the second set of experiments, seated subjects with the arm horizontal resisted baseline torques produced by a motor that acted to extend the elbow joint. Unexpected increases and decreases in torque were superimposed on the baseline torque. The subjects either were instructed to intervene and return the elbow to the initial (90°) position, or were told, “Do not intervene voluntarily; let the motor move your arm.” Effort was reported both under baseline conditions and after the changes in torque. It was found that changes in effort were a function of the changes in torque opposed by the elbow flexors, and were similar whether the subject had repositioned the arm or allowed it to be moved by the motor. In the latter case, the arm came to rest after displacements that were a function of the size and direction of the torque change. For individual subjects, the largest angular displacements ranged from ° 10° to °20° for changes in torque of ° 10 N.m. There was no evidence for any angular dependence of the effort judgments at a given torque over this angular range. Depending on whether effort is primarily an efferent perception proportional to voluntary motor activity or also has a significant afferent (involuntary) component, different models of motor control are supported by these data.     

Necropsy survey of gastric ulcers in a population of aged donkeys: prevalence, lesion description and risk factors

There is no information about the prevalence of gastric ulceration in donkeys or potential risk factors for its presence in donkeys. The donkey is a stoic, hardy animal that has not previously been thought to suffer from this disease. However, gastric ulceration was found to be a problem in a population of non-working UK donkeys resident at the Donkey Sanctuary and its prevalence was estimated by examining necropsy data over a 2-year period during 2005 to 2006. Associations with clinical and management factors were determined. In total, 426 donkeys were examined at necropsy to determine the presence of gastric ulceration. Lesions were described and scored according to a four-point scale. Management and clinical data from these donkeys were analysed to identify potential risk factors for the presence of gastric ulceration. Terminal blood samples were also studied to determine whether animals were exhibiting hyperlipaemia prior to death. Results showed that 41% (n = 174) of the donkeys studied had evidence of gastric ulceration at necropsy. Most (49%) of the ulcers were of a medium size (area of 2 cm2 - <10 cm2) and the most common site for ulcers was the margo plicatus. Of the donkeys examined, 18% had hyperlipaemia prior to or death or euthanasia and this was a risk factor for donkeys developing gastric ulceration; 62% of hyperlipaemia cases also displayed gastric ulceration (P < 0.001). Kidney disease was a potential risk factor (P = 0.02), with 74% of these animals having gastric ulceration. Donkeys that died or were euthanased due to respiratory disease were at a decreased risk of developing ulceration (P = 0.01) Donkeys fed a carbohydrate-based diet were more likely (P < 0.001) to have gastric ulceration than those fed a fibre-only diet, with 55% having gastric ulceration compared with 33% in the fibre-only group. This study has shown that gastric ulceration is commonly observed in donkeys at necropsy and may be extensive.     

The conservation value of paddock trees for birds in a variegated landscape in southern New South Wales. 1. Species composition and site occupancy patterns

The use of paddock trees by birds was assessed in a grazinglandscape in southern New South Wales, Australia. Seventy paddock treesites were surveyed for 20 min each in the morning, and 36sites were surveyed again at midday in March 2000. During this time, thepresence and abundance of birds was recorded. Several site and landscapevariables were measured at each site. These included tree species, atree size index, a measure of the crown cover density around the site,and proximity to the nearest woodland patch. During formal surveys, 31bird species, including several woodland species, were observed usingpaddock trees. Data from bird surveys in woodland patches that wereobtained in a separate study in November 1999 were used to comparewhether there was a relationship between the abundance of a given birdspecies in woodland patches and paddock trees. Many birds commonlydetected in woodland patches were also common in paddock trees. However,some birds with special habitat requirements were absent from paddocktrees although they were common in woodland patches. Site occupancypatterns were modelled for several guilds of birds using logisticregression. Foliage-foraging birds were more likely to occupy clumps oftrees and sites with a high tree size index. Nectarivores appeared to bemore likely to be detected at sites more than 200 m fromwoodland, although this result was marginally non-significant(P = 0.08). The probability of detecting granivoreswas higher at sites with a low tree size index. Open country specieswere most likely to occupy large trees and sites that were located morethan 200 m from the nearest woodland patch. The value ofpaddock trees may have been underestimated in the past because a widevariety of bird species use paddock trees on a regular basis. Ensuringthe continued survival of paddock trees should be an important aspect offuture conservation and revegetation efforts.     

Isolation of individual egg cells and zygotes in Alstroemeria followed by manual selection with a microcapillary-connected micropump

AIMS: To develop a procedure for isolating living egg cells and zygotes from Alstroemeria ovules. SCOPE: An attempt was made to isolate egg cells and zygotes from the ovules of Alstroemeria aurea. The ovules were histologically observed using a clearing procedure which revealed the localization and sizes of the embryo sacs and egg apparatus within the ovules. For the isolation of egg cells, ovules were cut into sections with a surgical blade and treated with an enzyme solution. Subsequently, these ovule sections were dissected using a glass needle under an inverted microscope. Egg cells successfully isolated by this procedure were collected using microcapillaries connected to a micropump. For zygote isolation, ovules were excised from ovaries 24 h after self-pollination. By treating excised ovules with an enzyme solution and subsequently dissecting them using a glass needle, zygotes were successfully isolated from the ovules and collected with a microcapillary. The isolated zygotes were associated with pollen tubes and one of the synergids. Egg cells and zygotes were viable for up to 2 h following isolation, as determined by fluorescein diacetate staining. CONCLUSIONS: The procedures for isolating egg cells and zygotes in Alstroemeria were established, and each egg cell and zygote was captured with a microcapillary.