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1.
龙茹  李玉花  徐启江 《生命科学》2007,19(2):127-131
microRNAs(miRNAs)是生物体内源长度约为20—23个核苷酸的非编码小RNA,通过与靶mRNA的互补配对而在转录后水平上对基因的表达进行负调控,导致mRNA的降解或翻译抑制。到目前为止,已报道有几千种miRNA存在于动物、植物、真菌等多细胞真核生物中,进化上高度保守。在植物和动物中,miRNA虽然都是通过与其靶基因的相互作用来调节基因表达,进而调控生物体的生长发育,但miRNA执行这种调控作用的机理却不尽相同。同时miRNA在动植物体内的形成过程也存在很多的不同之处。本文综述了动植物miRNA的生物合成、作用机理、生物功能等方面的研究进展。  相似文献   

2.
I sketch briefly some of the more influential theories concerned with the moral status of nonhuman animals, highlighting their biological/physiological aspects. I then survey the most prominent empirical research on the physiological and cognitive capacities of nonhuman animals, focusing primarily on sentience, but looking also at a few other morally relevant capacities such as self-awareness, memory, and mindreading. Lastly, I discuss two examples of current animal welfare policy, namely, animals used in industrialized food production and in scientific research. I argue that even the most progressive current welfare policies lag behind, are ignorant of, or arbitrarily disregard the science on sentience and cognition.  相似文献   

3.
In the past decade, the development of new DNA, RNA, and protein technologies has greatly incremented the knowledge about the organization and expression of mitochondrial DNA. The complete base sequence of mitochondrial DNA of several animals is known and many data are rapidly accumulating on the mitochondrial genomes of other systems. Here we discuss the results so far obtained that disclosed unexpected features of mitochondrial genetics. Furthermore, mitochondrial DNA has become established as a powerful tool for evolutionary studies in animals. Evidences are presented demonstrating that the evolution of mitochondrial DNA has proceeded in different ways in the various taxonomic groups. Data on heteroplasmic animals, which demonstrate the rapid evolution of mitochondrial DNA, are also presented.  相似文献   

4.
Summary The purpose of this study is to collaborate with clinicians who are involved in the treatment of certain types of cancer with BCG. Different massive doses of BCG were inoculated by various routes in small animals and three types of toxicity were studied: acute, chronic, and subacute toxicity. It is shown that BCG is not toxic mainly on the basis of mortality and weight variations of animals. Surprisingly, it was found that small animals could survive several doses of 2000 mg/kg of weight, by the subcutaneous route.  相似文献   

5.
The effects of a progesterone antagonist, lilopristone (ZK 98.734), on induction of menstruation, inhibition of implantation or pregnancy, and termination of early and mid-pregnancy were studied in bonnet monkeys. In the regularly menstruating animals, administration of lilopristone (25 mg/day, s.c.) during the mid-luteal phase (Days 20-22 of the menstrual cycle) induced menstruation within 2-4 days after the initiation of treatment. A premature drop in circulating progesterone levels was also observed. The luteolytic effect of lilopristone was prevented by exogenous treatment with hCG; however, the animals showed premature menstruation, in spite of high progesterone levels (above 4 ng/ml). Treatment around the time of implantation (between Days 8 and 12 after the mid-cycle peak in estradiol levels) in mated animals provided 100% pregnancy protection. Treatment of pregnant animals on Days 30-32 of the menstrual cycle, i.e. about Day 20 after the estradiol peak, induced abortion in 8 of 10 animals. A significant (p less than 0.05) decrease in serum progesterone levels was observed on Day 3 after the initiation of treatment. However, the decrease was slower (slope: -0.36, r: 0.96) compared to that observed in nonpregnant animals (slope: -0.72, r: 0.95). In the other two animals, pregnancy was not affected. However, when the treatment was delayed until about Day 50 after the estradiol peak, all four animals aborted. This study suggests that lilopristone is a progesterone antagonist with a potential to induce menstruation, inhibit nidation, and terminate pregnancy. The antifertility effects are mediated through blocking progesterone action at the endometrium as well as decreasing progesterone bioavailability, which appears to be due to its effects on gonadotropin release.  相似文献   

6.
Bats are commonly found all over the world and provide significant ecosystem services. These animals are facing serious threats due to various anthropogenic activities, including hunting. Additionally, bats are often not particularly well liked due to their non-aesthetic characteristics. A positive attitude to these animals is essential to protect them through appropriate conservation measures involving public intervention. Current high school students are the conservationists of the future, and the extent of support for bat conservation received from this and future generations is dependent upon their attitude toward these animals. It is therefore important to assess their perceptions of bats so that appropriate awareness programs can be devised, and negative attitudes (if any) rectified. The present study aimed to understand this aspect in order to provide inputs for shaping positive attitudes toward bat conservation. The study was undertaken in Barak Valley, Assam, India, where 65 bat colonies had already been recorded. A total of 3,059 high school students from 36 schools situated in their vicinity were questioned using a close-ended questionnaire to determine their perceptions. The responses received were divided among three categories: familiarity with bats, opinion on bats, and attitudes toward conservation, and were ranked on a scale of 10, based on selected aspects. Most students were awarded a score of four, indicating an average knowledge and opinion of bats. These findings suggest that awareness programs are urgently needed in schools to improve the general knowledge of and attitudes toward bats, and to inspire the next generation of bat conservationists.  相似文献   

7.
Recognition of unacceptable cruelty to animals in pasttimes such as bull-baiting, dates in Britain from the early 19th century. The Society for the Prevention of Cruelty to Animals was founded in 1824. Several bills to curb cruelty were discussed in Parliament, and the Cruel and Improper Treatment of Cattle Act was passed in 1822. Other Acts have followed over the years. Cruelty in the form of painful scientific experiments, including dissection of living, conscious animals, vivisection, was proscribed by the Cruelty to Animals Act 1876. That Act required anyone wishing to experiment with animals to obtain a licence from the Secretary of State. Conditions for issue of licences were strict and remain so to this day. The Act is still valid, and is enforced by the Home Office, with its medical and veterinary Inspectors. The Cruelty to Animals Act 1876 allows experiments on animals under strictly controlled conditions. Experiments must have the clear objective of improving the welfare of man and/or animals. Benefits from experiments carried out under the Act have been enormous, covering every aspect of diagnosis, treatment, and prophylaxis in human and veterinary medicine. Coincidentally, the welfare of laboratory animals has also been greatly improved. There has always been some opposition to the use of animals in biomedical research. The subject is emotive but, by and large, discussion has been rational and within the law. In recent years, however, the morality of using experimental animals has been examined more closely. The possibility of replacing them by alternative methods has been investigated. Where these alternatives are applicable, they are used and further research on them continues. The questioning of animal experiments has emphasized the need to look constantly at animal welfare to ensure humane treatment of all animals, especially those restricted in a laboratory or on a farm. Attention has been drawn in this work to our existing laws protecting animals, but new legislation is being demanded, not only by some lay welfare groups but also by scientists. Hence, it has become very important to discuss various ways of ensuring animal welfare, including by legislation, especially with those knowledgeable in laboratory animal science and animal experiments.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

8.
In July and August 1995, the authors interviewed elderly Malagasy with knowledge of the traditions and natural history of their home areas, centered on the villages of Belo-sur-mer, Antsira, and Ambararata, on the southwest coast of Madagascar.
Several individuals related personal experiences in which they claim to have seen and heard animals that do not match any known extant animal of Madagascar. Two of the mystery animals, known locally as the kilopilopitsofy and kidoky, were described in terms similar to creatures detailed in historical accounts and folklore recorded in Madagascar between the mid-1600s and the end of the nineteenth century. The former of these has been compared by some authors to the dwarf hippopotamus and the latter to a giant lemur, animals generally inferred from radiocarbon dating of last known occurrences to have gone extinct early in the present millennium or perhaps a few centuries later.
Stories by these same informants concerning extant animals demonstrate their accurate knowledge of the fauna. Magical powers are ascribed to some animals, such as the bokyboky, a viverrid (Mungotictis) that occurs in the region. Radiocarbon dates obtained recently on some of the extinct megafauna, showing that some extirpated taxa may have survived until recent centuries, confirm that ethnographic sources of information on these species should not automatically be dismissed as irrelevant or unreliable. [Madagascar, extinctions, megafauna, hippopotamus, lemur]  相似文献   

9.
Daphnia pulex were raised under nine light intensities (0, 1.7, 3.5, 7, 14, 28, 55, and 110 ft-c), polarized light (6.6 ft-c), and four wavelength ranges.Light intensity significantly affected the relationship between filtering rate and body size of unacclimated animals. The b values were lowest at 7 and 14 ft-c and they increased above 7 ft-c as light intensity increased. There were significant differences among b values and adjusted means for unacclimated animals. Acclimation to their respective conditions resulted in some significant differences between b values and adjusted means. For acclimated animals there were no significant differences among b values but there were some differences among adjusted means. The filtering rates of unacclimated and acclimated animals were lower at 14 ft-c while 1.7 and 3.5 ft-c were generally stimulatory and the effect was more pronounced in larger animals. Light intensities above 28 ft-c tended to suppress the filtering rate of small unacclimated animals and stimulate filtering rate in larger unacclimated animals. After acclimation, intensities above 7 ft-c did not affect the filtering rate of either small or large animals.The effect of polarized light on filtering rate was inseparable from the effect of light intensity, however, acclimation to polarized light resulted in a significantly higher b value.There were no significant effects of wavelength among b values for unacclimated animals and the adjusted mean for blue wavelengths was significantly higher than for violet wavelengths. There were no significant differences among b values or adjusted means for acclimated animals. Acclimation to their respective wavelengths did result in some significant differences between b values and adjusted means. Except for the effects of blue wavelengths on unacclimated animals and red wavelengths on acclimated animals, the effects of wavelengths are inseparable from the effects of light intensity.This paper is part of a Ph.D. Thesis submitted to the Faculty of Graduate School of The University of Kansas.Supported in part by a NSF Summer Traineeship and a grant from the Research Corporation to St. Olaf College, Northfield, Minnesota 55057.  相似文献   

10.
At the beginning of 2005, the European Commission published its fourth report on the statistics of the number of animals used for experimental and other scientific purposes. A total of 10.7 million animals were used within the Member States of the European Union (EU) in 2002, an increase of almost a million animals since the 1999 report. France, Germany and the UK continue to be the largest users of animals for scientific purposes, and mice, rats, fish and birds remain the most commonly-used animals. For the first time, all 15 Member States used the standardised EU tables, as had been agreed in 1998. This has made it easier to identify areas on which Three Rs initiatives should be focused. Nevertheless, the reporting system still has a number of serious deficiencies. In particular, there are insufficient data on the numbers of animals that are kept or bred for research purposes, the numbers of transgenic animals, and the severity of procedures that are applied.  相似文献   

11.
The history of the aye-aye in captivity outside Madagascar is briefly reviewed. Maintenance conditions of the 3 animals currently housed at the Paris Zoo are described. In addition to providing information on the diet and feeding behaviour of the animals, details of enclosure size, humidity level, temperature, cage furniture and light cycle are provided. Preliminary behavioural observations on mother-infant relationships, grooming, nest building and play are also included.  相似文献   

12.
Primates are known for their use of the hand in many activities including food grasping. Yet, most studies concentrate on the type of grip used. Moreover, kinematic studies remain limited to a few investigations of the distal elements in constrained conditions in humans and macaques. In order to improve our understanding of the prehension movement in primates, we analyse here the behavioural strategies (e.g., types of grip, body postures) as well as the 3D kinematics of the whole forelimb and the trunk during the prehension of small static food items in five primate species in unconstrained conditions. All species preferred the quadrupedal posture except lemurs, which used a typical crouched posture. Grasp type differed among species, with smaller animals (capuchins and lemurs) using a whole-hand grip and larger animals (humans, gorillas, chimpanzees) using predominantly a precision grip. Larger animals had lower relative wrist velocities and spent a larger proportion of the movement decelerating. Humans grasped food items with planar motions involving small joint rotations, more similar to the smaller animals than to gorillas and chimpanzees, which used greater rotations of both the shoulder and forearm. In conclusion, the features characterising human food prehension are present in other primates, yet differences exist in joint motions. These results provide a good basis to suggest hypotheses concerning the factors involved in driving the evolution of grasping abilities in primates.  相似文献   

13.
In this general, strongly pro-animal, and somewhat utopian and personal essay, I argue that we owe aquatic animals respect and moral consideration just as we owe respect and moral consideration to all other animal beings, regardless of the taxonomic group to which they belong. In many ways it is more difficult to convince some people of our ethical obligations to numerous aquatic animals because we do not identify or empathize with them as we do with animals with whom we are more familiar or to whom we are more closely related, including those species (usually terrestrial) to whom we refer as charismatic megafauna. Many of my examples come from animals that are more well studied but they can be used as models for aquatic animals. I follow Darwinian notions of evolutionary continuity to argue that if we feel pain, then so too do many other animals, including those that live in aquatic environs. Recent scientific data ('science sense') show clearly that many aquatic organisms, much to some people's surprise, likely suffer at our hands and feel their own sorts of pain. Throughout I discuss how cognitive ethology (the study of animal minds) is the unifying science for understanding the subjective, emotional, empathic, and moral lives of animals because it is essential to know what animals do, think, and feel as they go about their daily routines. Lastly, I argue that when we are uncertain if we are inflicting pain due to our incessant, annoying, and frequently unnecessary intrusions into the lives of other animals as we go about 'redecorating nature' (removing animals or moving them from place to place), we should err on the side of the animals and stop engaging in activities that cause pain and suffering.  相似文献   

14.
Occurrence, fate, and biodegradation of estrogens in sewage and manure   总被引:10,自引:0,他引:10  
The estrogens estrone (E1), 17α-estradiol (E2α), 17β-estradiol (E2β), and estriol (E3) are natural sex hormones produced by humans and animals. In addition, there are some synthetic estrogens, such as 17α-ethinylestradiol (EE2), used for contraception purposes. These compounds are able to produce endocrine disruption in living organisms at nanogram-per-liter levels. In both humans and animals, estrogens are excreted in urine and feces, reaching the natural environment through discharge from sewage treatment plants (STP) and manure disposal units. In STPs, hormone removal depends on the type of treatment process and on different parameters such as the hydraulic and sludge retention times. Thus, hormone elimination rates vary from 0% to 90% in different STPs. Animals are also an important source of estrogens in the environment. Indeed, animals produce high concentrations of hormones which will end up in manure which is typically spread on land. Hence, waste-borne animal hormones may transfer these pollutants to the soil. The purpose of this review is to highlight the significance for both health and the environment of pollution by estrogens and critically review the existing knowledge on their fate and removal in different treatment processes. Relevant information on the microbial degradation of hormones and metabolic pathways is also included.  相似文献   

15.
The suffering of nonhuman animals has become a noted factor in deciding public policy and legislative change. Yet, despite this growing concern, skepticism toward such suffering is still surprisingly common. This paper analyzes the merits of the skeptical approach, both in its moderate and extreme forms. In the first part it is claimed that the type of criterion for verification concerning the mental states of other animals posed by skepticism is overly (and, in the case of extreme skepticism, illogically) demanding. Resting on Wittgenstein and Husserl, it is argued that skepticism relies on a misguided epistemology and, thus, that key questions posed by it face the risk of absurdity. In the second part of the paper it is suggested that, instead of skepticism, empathy together with intersubjectivity be adopted. Edith Stein’s take on empathy, along with contemporary findings, are explored, and the claim is made that it is only via these two methods of understanding that the suffering of nonhuman animals can be perceived.  相似文献   

16.
Summary Species of the amphipod genus Paraceradocus found near the Antarctic Peninsula were observed in aquaria. The animals live under stones in burrows in sediment which they excavate with their gnathopods. During burrowing the animal regularly turns backwards in a somersault-like movement. Paraceradocus feeds on detritus, which is manipulated by the gnathopods and the antennes. The gnathopods are also used for grooming. A dense brush of setae at the medial surface of the carpi of the gnathopods I is used to clean off fine particles from the antennes. These particles are transferred to the maxillipeds and are ingested. The rear appendages are mainly cleaned by the gnathopods II. Young animals sitting between the gnathopods of the adult participate in feeding.  相似文献   

17.
L. Sømme 《Cryobiology》1981,18(2):212-220
Because of their dominant role in the fauna of alpine, Arctic and Antarctic locations Collembola and mites are of particular interest regarding adaptations to low temperatures. No freezing-tolerant species have been found in these groups of terrestrial arthropods, and it appears that all species depend entirely on supercooling to survive the lower temperatures of their habitats. While summer animals have high supercooling points, an increase in supercooling ability occurs during autumn and early winter, and can be explained as a two-step process. Initially gut content has to be eliminated to avoid heterogeneous nucleation at high subzero temperatures due to foreign nucleating agents. Second, supercooling is further enhanced through accumulation of glycerol or other lowmolecular cryoprotective substances. Further studies are needed on the ability of such animals to avoid inoculative freezing in their microhabitats.  相似文献   

18.

Objective

Hemorrhagic shock accompanied by injury represents a major physiologic stress. Fasted animals are often used to study hemorrhagic shock (with injury). A fasted state is not guaranteed in the general human population. The objective of this study was to determine if fed animals would exhibit a different metabolic profile in response to hemorrhagic shock with trauma when compared to fasted animals.

Methods

Proton (1H) NMR spectroscopy was used to determine concentrations of metabolites from four different compartments (liver, muscle, serum, urine) taken at defined time points throughout shock/injury and resuscitation. PLS-DA was performed and VIP lists established for baseline, shock and resuscitation (10 metabolites for each compartment at each time interval) on metabolomics data from surviving animals.

Results

Fed status prior to the occurrence of hemorrhagic shock with injury alters the metabolic course of this trauma and potentially affects mortality. The death rate for CPF animals is higher than FS animals (47 vs 28%). The majority of deaths occur post-resuscitation suggesting reperfusion injury. The metabolomics response to shock reflects priorities evident at baseline. FS animals raise the baseline degree of proteolysis to provide additional amino acids for energy production while CPF animals rely on both glucose and, to a lesser extent, amino acids. During early resuscitation levels of metabolites associated with energy production drop, suggesting diminished demand.

Conclusions

Feeding status prior to the occurrence of hemorrhagic shock with injury alters the metabolic course of this trauma and potentially affects mortality. The response to shock reflects metabolic priorities at baseline.  相似文献   

19.
Miniaturisation of somatic cells in animals is limited, for reasons ranging from the accommodation of organelles to surface-to-volume ratio. Consequently, muscle and nerve cells vary in diameters by about two orders of magnitude, in animals covering 12 orders of magnitude in body mass. Small animals thus have to control their behaviour with few muscle fibres and neurons. Hexapod leg muscles, for instance, may consist of a single to a few 100 fibres, and they are controlled by one to, rarely, 19 motoneurons. A typical mammal has thousands of fibres per muscle supplied by hundreds of motoneurons for comparable behavioural performances. Arthopods—crustaceans, hexapods, spiders, and their kin—are on average much smaller than vertebrates, and they possess inhibitory motoneurons for a motor control strategy that allows a broad performance spectrum despite necessarily small cell numbers. This arthropod motor control strategy is reviewed from functional and evolutionary perspectives and its components are described with a focus on inhibitory motoneurons. Inhibitory motoneurons are particularly interesting for a number of reasons: evolutionary and phylogenetic comparison of functional specialisations, evolutionary and developmental origin and diversification, and muscle fibre recruitment strategies.  相似文献   

20.
The intricate causal relationships between disease in man and disease in animals first began to be elucidated in the mid-19th century. Although the connections between animal and human disease are now generally understood, individuals as well as societies remain slow to act on this knowledge. This paper examines the gradual recognition of these disease connections and explores the parallel theme of man's reluctance to appreciate the implications of these connections. It identifies factors that have inhibited the realization of the links between disease in man and animals, and discusses several milestones in the scientific elucidation of these links. Beginning with emerging concerns over the relationship between bovine and human tuberculosis in the 1860s, it follows the discovery of insect vectors, animal reservoirs, and the links between animals, influenza, and man. Despite warnings of the potential significance for human disease of patterns of changes in the relationship with animals and the natural world, scientists have continued to treat human and animal health as largely independent disciplines, while historians too have neglected this important aspect of human disease.  相似文献   

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