Brain peptides: what, where, and why?

Within the past decade, a large number of peptides have been described within the vertebrate central nervous system. Some of these peptides were previously known to be present in nonneural vertebrate tissues, as well as in lower species, in which they may serve as primitive elements of intercellular communication prior to the development of neuronal or endocrine systems. In vertebrates, these peptides are thought to have neurotransmitter or neuromodulatory roles and appear to be involved in the regulation of a number of homeostatic systems, although the mechanisms of their actions are still unclear.     

Microsomal hydroxylase induction in liver cell culture by phenobarbital, polycyclic hydrocarbons, and p,p'-DDT

Aryl hydrocarbon hydroxylase induction by phenobarbital, polycyclic hydrocarbons, and the insecticide, 2.2-bis(p-chlorophenyl)-1,1,1-trichloroethane (p,p'-DDT), occurs in rat fetal liver cell cultures. The maximum net rate at which the hydroxylase activity accumulates is about the same when phenobarbital, 3-methlcholanthrene, or benz[a]anthracene is in the growth medium at optimum concentrations. An additive effect is obtained when either phenobarbital or p.p'-DDT is present with a polycyclic hydrocarbon in the growth medium, but not when the cells are treated with phenobarbital plus p.p'-DDT or with the combination of two polycyclic hydrocarbons.     

Sleep disorders: disorders of arousal? Enuresis, somnambulism, and nightmares occur in confusional states of arousal, not in "dreaming sleep"

In summary, the classical sleep disorders of nocturnal enuresis, somnambulism, the nightmare, and the sleep terror occur preferentially during arousal from slow-wave sleep and are virtually never associated with the rapid-eye-movement dreaming state. Original data are reported here which indicate that physiological differences from normal subjects, of a type predisposing the individual to a particular attack pattern, are present throughout the night. The episode, at least in the case of enuresis, appears to be simply a reinforcement of these differences to a clinically overt level. A number of features are common to all four sleep disorders. These had been shown previously to be attributable to the arousal itself. New data obtained by means of evoked potential techniques suggest that these common symptoms of the confusional period that follows non-REM sleep are related to alterations of cerebral reactivity, at least of the visual system. The symptoms which distinguish the individual attack types (that is, micturition, prolonged confusional fugues, overt terror) appear to be based upon physiological changes present throughout sleep which are markedly accentuated during arousal from slow-wave sleep. These changes may in some way be related to diurnal psychic conflicts. But, to date, it has proved impossible to demonstrate potentially causal psychological activity, dreaming or other forms of mental activity, or even a psychological void in sleep just preceding the attacks. The presence of all-night or even daytime predisposing physiological changes and the difficulty in obtaining any solid evidence of a preceding psychological cause explain, no doubt, why the results of efforts to cure the disorders at the moment of their occurrence (for example, by conditioning procedures in nocturnal enuresis) have been far from satisfactory. I stress the points that the attacks are best considered disorders of arousal and that the slow-wave sleep arousal episode which sets the stage for these attacks is a normal cyclic event. Indeed it is the most intense recurrent arousal that an individual regularly experiences. The most fruitful possibilities for future research would appear to be more detailed studies of those physiological changes that predispose individuals to certain types of attacks when they undergo intense arousal or stress; the reversal of these changes by psychological or pharmacological means; and more refined investigations of the physiological and psychological characteristics of the process of cyclic arousal from non-REM sleep.     

Porotic hyperostosis, anemias, malarias, and marshes in the prehistoric Eastern Mediterranean

Porotic hyperostosis, formerly called osteoporosis symmetrica, is an overgrowth of the spongy marrow space of the skull. In children, other bones may also be affected. The disease is a consequence of one of the thalassemias or sicklemia. These anemias are balanced polymorphisms which are apparently maintained by falciparum malaria. Falciparum malaria spread over the anopheline belts of the Old World in coincidence with porotic hyperostosis, but did not penetrate the New World. Here some other parasitism or deficiency anemia must have been the cause of porotic hyperostosis in ancient times. In Anatolia, Greece, and Cyprus from the seventh to second millennia B.C., porotic hyperostosis occurred frequently in early farmers who lived in marshy areas, but rarely in inhabitants of dry or rocky areas or in latest Paleolithic hunters. As shown by skeletal samples from Greece, the frequency of the disease decreased as farming methods improved. However, from Hellenistic to Romantic times it again increased together with increases in the incidence of malaria and in poorer farming. There are correlations between porotic hyperostosis and adult stature and fertility. The mutations producing falciparum malaria therefore must antedate seventh millenium B.C. and I think may have an Eastern Mediterranean origin.     

高粱舟蛾生物学特性的研究

高粱舟蛾Dinara combusta(Walker)，又称高梁社蛾，是一种暴食性食叶害虫，主要危害玉米，高粱，甘蔗等，在河北省以危害夏玉米最生，由于该虫 正值夏玉米灌浆期，主要取食中部果穗上下1－2片叶，故对产量蚊蝇衅大，研究表明，该虫在全省1年发生1代，以蛹在土中越 ，翌年6月中下旬开始羽化，7月中下我为幼虫发生盛期，越冬虫源，气候，天敌及食物因子对其种群数量消长影响较大。     

Gender, livestock assets, resource management, and food security: Lessons from the SR-CRSP

North Sumatra and West Java in Indonesia, the Andes of Bolivia and Peru, Western Province, the Coast and Machakos in Kenya, were Small Ruminant Collaborative Research Support Program (SR-CRSP) sites in which the role of small ruminants was studied and where technological interventions were designed. In all cases the target groups were poor rural households that could maintain sheep, goats, or South American camelids. The objective was to increase the welfare of families through the use of small ruminant technologies. Access to and control of resources, and intrahousehold dynamics were analyzed to understand if, how, and when, technological interventions help achieve this objective. The way in which the studied villages integrate into the market, the specific role that livestock and other productive enterprises play in the household economy, the risks faced by families in rural areas condition the role of livestock and other resource management technologies. As an asset, small and large stock are gendered, but this is qualified by the alternatives that household members have. Small ruminants under the domain of women, either through production or marketing, are shown to contribute to in-kind consumption or, as liquid assets, to household welfare purchases, in the case of Andean agropastoral households and households in Kenya. Women are also managers of the grazing areas, which are often fallow fields. The research experiences show the relationship between gender, resource management, and the ability to build livestock assets and security, in different houehold production systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

宁波黄山松木包装中程氏伞滑刃线虫记述

    宁波出入境检验检疫局植检实验室在对本地热处理企业线虫处理效果进行监测时,从一批采自余姚四明山林场的黄山松(Pinus taiwanensi)木包装中截获一种伞滑刃属线虫.对该线虫进行培养、形态学观察、测量以及分子研究,鉴定为程氏伞滑刃线虫(Bursaphelenchus chengi Li, Trinh, Waeyenberge &; Moens, 2008).该线虫属abietinus组,侧区有2条侧线,雄虫交合刺成对,强壮,长约18 ～22 μm,末端约1/3处强烈向腹面弯曲.雌虫尾端略向腹面弯曲,末端钝圆或尖,有时有不规则的尾尖突.该线虫与树皮象伞滑刃线虫(B. hylobianum)、安东尼伞滑刃线虫(B. antoniae)在形态上十分接近,但ITS-RFLP图谱以及序列分析结果有明显差异.目前仅南京口岸曾从来自我国台湾的木质包装中截获该线虫.     

Carbonic anhydrase interaction with DDT, DDE, and dieldrin

The active site of various carbonic anhydrases is not blocked by DDT. DDE, or dieldrin. Impairment of catalytic efficiency can only be documented in opalescent test solutions in which the insecticides are present in excess of their solubility limit. These slowly forming precipitates occlude enzyme from solution and furnish a physical explanation of the supposed inhibition. The amounts occluded depend, among other things, on the conformational and topographical characteristics of the particular carbonic anhydrase molecules.     

Segregation of form, color, movement, and depth: anatomy, physiology, and perception

Anatomical and physiological observations in monkeys indicate that the primate visual system consists of several separate and independent subdivisions that analyze different aspects of the same retinal image: cells in cortical visual areas 1 and 2 and higher visual areas are segregated into three interdigitating subdivisions that differ in their selectivity for color, stereopsis, movement, and orientation. The pathways selective for form and color seem to be derived mainly from the parvocellular geniculate subdivisions, the depth- and movement-selective components from the magnocellular. At lower levels, in the retina and in the geniculate, cells in these two subdivisions differ in their color selectivity, contrast sensitivity, temporal properties, and spatial resolution. These major differences in the properties of cells at lower levels in each of the subdivisions led to the prediction that different visual functions, such as color, depth, movement, and form perception, should exhibit corresponding differences. Human perceptual experiments are remarkably consistent with these predictions. Moreover, perceptual experiments can be designed to ask which subdivisions of the system are responsible for particular visual abilities, such as figure/ground discrimination or perception of depth from perspective or relative movement--functions that might be difficult to deduce from single-cell response properties.     

City size effects, trends, and policies

As cities increase in size, so do wage rates for the same work. There is evidence that the wage differential is persistent and stable over time, which suggests that the differential does not arise from a lack of adjustment that is in process of correction. Indeed, there is an inverse relation between size and growth rate. Large metropolitan areas with high wage rates have been losing population in recent years, which is hardly a sign that their higher wage rates are temporary inducements to workers to move into those cities. It is much more plausible that the differential is a more-orless permanent money payment that compensates urban residents for costs they bear as population size increases. This argument does not deny that there are nonwage benefits as well as costs of city size, that city size effects may vary between individuals and groups, or that there may be scope for improved policy on population distribution. Nonetheless, the benefits of size seem to be outweighed by the costs; all types and groups of people generally can and do move about until alternative locations are less attractive than their current location; and solutions to population distribution problems will often emerge as byproducts to the solutions of more basic problems.     

Dendrites, viscous fingers, and the theory of pattern formation

There has emerged recently a new theoretical picture of the way in which patterns are formed in dendritic crystal growth and in the closely analogous phenomenon of viscous fingering in fluids. Some interesting questions that arise in connection with this theory include: How broad is its range of validity? How do we understand dynamic stability in systems of this kind? What is the origin of sidebranches? Can weak noise, or even microscopic thermal fluctuations, play a role in determining the macroscopic features of these systems?     

Helix geometry, hydration, and G.A mismatch in a B-DNA decamer

The DNA double helix is not a regular, featureless barberpole molecule. Different base sequences have their own special signature, in the way that they influence groove width, helical twist, bending, and mechanical rigidity or resistance to bending. These special features probably help other molecules such as repressors to read and recognize one base sequence in preference to another. Single crystal x-ray structure analysis is beginning to show us the various structures possible in the B-DNA family. The DNA decamer C-C-A-A-G-A-T-T-G-G appears to be a better model for mixed-sequence B-DNA than was the earlier C-G-C-G-A-A-T-T-C-G-C-G, which is more akin to regions of poly(dA).poly(dT). The G.A mismatch base pairs at the center of the decamer are in the anti-anti conformation about their bonds from base to sugar, in agreement with nuclear magnetic resonance evidence on this and other sequences, and in contrast to the anti-syn geometry reported for G.A pairs in C-G-C-G-A-A-T-T-A-G-C-G. The ordered spine of hydration seen earlier in the narrow-grooved dodecamer has its counterpart, in this wide-grooved decamer, in two strings of water molecules lining the walls of the minor groove, bridging from purine N3 or pyrimidine O2, to the following sugar O4'. The same strings of hydration are present in the phosphorothioate analog of G-C-G-C-G-C. Unlike the spine, which is broken up by the intrusion of amine groups at guanines, these water strings are found in general, mixed-sequence DNA because they can pass by unimpeded to either side of a guanine N2 amine. The spine and strings are perceived as two extremes of a general pattern of hydration of the minor groove, which probably is the dominant factor in making B-DNA the preferred form at high hydration.     

Virus-like antigen, antibody, and antigen-antibody complexes in hepatitis measured by complement fixation

Complement fixation techniques are described for measuring a virus-like antigen associated with viral hepatitis. Antigen was found in the blood of 98 percent of 130 patients, with the serum form of hepatitis, from whom multiple samples were obtained. Antibodies arising during hepatitis are usually combined with antigen and cause anticomplementary activity in the serum, which is reversible with excess antigen or antibody. Tests for antigen and specific anticomplementary activity can be used diagnostically and to screen blood donors for hepatitis carriers.     

Replamineform: a new process for preparing porous ceramic, metal, and polymer prosthetic materials

The replamineform process (meaning replicated life forms) is a technique for duplicating the microstructure of carbonate skeletal components in ceramic, metal, or polymer materials. The special pore structures of marine invertebrate skeletal materials such as echinoid spines and corals, which are difficult or impossible to create artificially, can thus be copied in useful materials. Of immediate interest is the possibility of using these replicated microstructures in the fabrication of orthopedic prosthetic devices. By means of this technique, prosthetic materials having a controlled pore microstructure for optimum strength and tissue ingrowth may be obtained.     

Landscape development, forest fires, and wilderness management

Both the landforms and the vegetation of the earth develop to states that are maintained in dynamic equilibrium. Short-term equilibrium of a hillslope or river valley results from intersection between erosional and depositional tendencies, controlled by gravitational force and the efficiency of the transporting medium. Long-term equilibrium of major landforms depends on crustal uplift and the resistance of the rock to weathering. In most parts of the world landscape evolves toward a peneplain, but the reduction rate approaches zero as the cycle progresses, and the counteracting force of crustal uplift intercedes before the end form is reached. Davis described this theoretical model in elegant terms. Leopold and Hack have provided a new and quantitative understanding of short-range geomorphic interactions that tend to discredit the Davisian model in the eyes of many. However, the substitute models of quasi-equilibrium or dynamic equilibrium merely describe short-range situations in which this or that Davisian stage is maintained despite uplift or downwasting. Given crustal stability and an unchanging climate, landforms would presumably still evolve through Davisian stages. However, the Davis model cannot be tested, for despite tremendous inventions in geochronology and impressive advances in stratigraphic knowledge, we cannot yet establish the rates or even the fact of crustal uplift in most areas. We are left with an unresolvable problem, for the sedimentary records of erosional history are largely inaccessible, undatable, and indecipherable, at least in the detail necessary to describe long-term evolution of the landscape. We know more about the evolution and maintenance of vegetation assemblages than about landform evolution, for even long-term vegetation sequences are within the scope of radiocarbon dating, and the biostratigraphic record is detailed. Even here, however, distinctions between short-term and long-term situations must be made, so that Clements' grand scheme of vegetational climax-created soon after Davis's model of landform development-can be evaluated in terms of modern knowledge. Disillusion with the climax model paralleled disillusion with Davis's model in the 1950's, but the climax model can be tested, because the record of vegetational history is accessible, datable, and decipherable. In the short term of a few decades, successional vegetation stages occur in variety of situations, as confirmed by observation or by techniques such as tree-ring analysis. The successional vegetation stages are reactions to nutrients, weather, competition, and consumption. Such succession implies long-term disequilibrium, or at least unidirectional development. The long-term controlling factor in Clements' model of vegetation development is climate. With climatic stability the succession will proceed to a climax. In the Appalachian Mountains, geomorphic, microclimatic, and edaphic conditions limit climax development, producing a polyclimax, which is generally sustained by the dominance of these factors. Death and regeneration of single forest trees is controlled mostly by windstorms. The distributional pattern may be locally transected by lightning fires, major windstorms, or washouts. However, the long-term stability of Appalachian forests is demonstrated by pollen stratigraphy. Although we can infer the long-term stability of Appalachian forests, the trends and mechanics of short-term vegetational succession are not fully understood, because lack of sizable areas of virgin forest limits investigations of natural conditions. In this respect, the eastern United States is already much like western Europe, where climatic and disturbance factors in vegetational history cannot be disentangled. In the Great Lakes region, a large area of virgin forest exists in the BWCA of northeastern Minnesota. Here short- and long-term studies show that for at least 9000 years the principal stabilizing factor has been the frequent occurrence of fire. Major fires occur so often that the vegetation pattern is a record of fire history. All elements in the forest mosaic are in various stages of postfire succession, with only a few approaching climax. Fire interrupts the successful sequence toward climax. Geomorphic and edaphic factors in vegetational distribution are largely submerged by the fire regime, except for bog and other lowland vegetation. Fire recycles nutrients and renews succession. Nevertheless, despite the fire regime, the resulting long-term equilibrium of the forest mosaic, characterized by severe and irregular fluctuations of individual elements, reflects regional climate. In the BWCA and the western mountains, large virgin forests can be preserved for study and wilderness recreation. These wilderness areas must be managed to return them to the natural equilibrium which has been disturbed by 50 to 70 years of fire suppression. The goal should be to maintain virgin forests as primeval wilderness. This can be done by management that permits fire and other natural processes to determine the forest mosaic. Mechanized tree-felling and other human disturbances should be kept to an absolute minimum. Natural landforms also should be preserved for study and for certain nondestructive recreational activities. It is somewhat late for the Colorado River and other rivers of the West, because natural balances are upset by drainagebasin disturbances. Modification of plant cover on hillslopes changes infiltration and erosion rates and thus the stream discharge and sediment load, so the stream balance is altered from primeval conditions. Scenic Rivers legislation should thus be used to restore certain river systems and their drainage basins. Mountain meadows, badlands, desert plains, and patterned permafrost terrain are extremely fragile and sensitive. Intricate stream and weathering processes leave patterns easily obliterated by mechanized vehicles. Tire tracks can last for decades or centuries. The mineral patina or lichen cover on desert or alpine rocks are records of long stability, and slight differences in their development record the relative ages of landforms, to the year in the case of lichens. Delicate color differences in a talus slope or desert fan show long-term effects just as does the arboreal vegetation mosaic in another climatic setting. Preservation of virgin wilderness for study is viewed by some as a selfish goal of scientists, to be achieved at the expense of commercial and recreational development. However, scientific study and nonmechanized recreational uses are compatible in wilderness areas. Furthermore, the public does appreciate intellectual stimulation from natural history, as witnessed by massive support for conservation, the Wilderness Act, and a dozen magazines like National Geographic. Finally, no knowledgeable American today is unaware that ecological insights are necessary to preserve the national heritage. Western dust bowls, deforested slopes, gullied fields, silted rivers, strip mine waste-lands, and the like might have been avoided had long-term problems been balanced against short-term profits. Many economic questions cannot be answered intelligently without detailed knowledge of extensive virgin ecosystems. Long-term values are enhanced by those uses of natural resources that are compatible with the preservation of natural ecosystems. Esthetically, virgin wilderness produced by nature is comparable to an original work of art produced by man. One deserves preservation as much as the other, and a copy of nature has as little value to the scientist or discerning layman as a reproduction of a painting has to an art scholar or an art collector. Nature deserves its own display, not just in tiny refuges but in major landscapes. Man is only one of literally countless species on the earth. Man developed for a million years in a world ecosystem that he is now in danger of destroying for short-term benefits. For his long-term survival and as an expression of his rationality and morality, he should nurture natural ecosystems. Some people believe that human love of nature is self-protective. For many it is the basis of natural religion. The opposition of many Americans to the Alaska pipeline is a manifestation of almost religious feeling; most never expect to see the Alaskan wilderness, but they are heartened to realize that it exists and is protected. The same can be said of those who contribute to save the redwoods in California. Here cost analysis fails to account for the enormous value people place on nature and on the idea of nature as contrasted to the private gain of a few developers. Americans admire European preservation of works of art. Europeans admire American foresight in setting aside national parks. However, the distribution of protected natural areas in America is uneven and inadequate, and vast areas continue to be developed or badly managed despite widespread new knowledge about long-term human interest in wilderness preservation. Darwin turned nature study into the study of natural history. He could observe natural features in vast undisturbed areas with no thought that human interference had been a factor in their development. Today such natural landscapes have practically vanished. Those that remain should be preserved as extensively as possible, and managed with scientific knowledge of the natural processes that brought them to being. At the present accelerating rate of exploitation, massive disturbance, and unscientific management, soon no natural areas will be left for research or wilderness recreation. Some say that scientific curiosity and the ability for recreation define man. This is reason enough for wilderness preservation. However, a more ominous conclusion that the survival of man may depend on what can be learned from the study of extensive natural ecosystems.     

Mass spectrometry of large, fragile, and involatile molecules

Desorption ionization makes it possible to obtain mass spectra of molecules whose vaporization by heating may lead to thermal degradation. Several methods are in use, but in general desorption is achieved by particle or photon bombardment of the sample and the mass spectra obtained by different methods are fundamentally similar. Desorption ionization techniques have been used to obtain mass spectra of biomolecules, including peptides, antibiotics, and oligosaccharides, for which normal mass spectral methods have been of limited power. Several examples are given of recent applications of these new techniques, and prospects for their further evolution are discussed.     

Aleuts, sea otters, and alternate stable-state communities

Reexamination of stratified faunal components of a prehistoric Aleut midden excavated on Amchitka Island, Alaska, indicates that Aleut prey items changed dramatically during 2500 years of aboriginal occupation. Recent ecological studies in the Aleutian Islands have shown the concurrent existence of two alternate stable nearshore communities, one dominated by macroalgae, the other by epibenthic herbivores, which are respectively maintained by the presence or absence of dense sea otter populations. Thus, rather than cultural shifts in food preference, the changes in Aleut prey were probably the result of local overexploitation of sea otters by aboriginal Aleuts.     

Self-stimulation of the brain; its use to study local effects of hunger,sex, and drugs

My conclusions are these: (i) The cells which mediate primary rewarding effects are located in a midline system running from the midbrain through the hypothalamus and midline thalamus and into the subcortical and cortical groups of the rhinencephalon. (ii) The cell groups which mediate primary rewarding effects are different from those which mediate primary punishing effects. (iii) Despite this relative independence, there are, undoubtedly, relationships of mutual inhibition existing between these two systems. Rewards do, among other things, tend to reduce sensitivity to pain, and punishments do tend to reduce rewarding effects. (iv) These primary reward systems of the brain are subdivided into specific drive-reward subsystems mediating the specific drives such as hunger and sex. (v) Because there are also subsystems of this set of rewarding structures sensitive to different chemical effects, it is reasonable to hope that eventually it will be possible to control the reward systems pharmacologically in cases where behavior disorders seem to result from deficits or surfeits of positive motivation.