Wood, bark and stem anatomy of New World species of Gnetum

Quantitative and qualitative data are presented for 11 collections of six species. The wide range of character states for the species is presented in the form of a key to emphasize their potential systematic correlations. Distinctive among these are phcllem characteristics. Fibre-tracheids are newly reported for lianoid Gnetum species. Cells previously thought to be like companion cells in secondary phloem are shown to be uniseriate rays, counterparts to uniseriate xylem rays. Laticifers are abundant in most of the species, and are newly described for secondary tissues of Gnetum. Presence of tyloses in laticifers of two species is apparently a new report for vascular plants. Tori are present in two New World Gnetum species, adding to the report in African species. Perforation plates are simple except near or in primary xylem, where they are simple or foraminate. Torus presence and foraminate perforation plate presence are features more reminiscent of Ephedra and other gymnosperms than of angiosperms. The bark of Gnetum is also very similar to that of Ephedra.     

Ecology of nematophagous fungi: vertical distribution in a deciduous woodland

Summary The distribution of nematophagous fungi in soil collected from a deciduous woodland is compared to various biotic and abiotic soil factors. The microfungi are isolated at all depths down to a maximum of 35 cm. Predators forming constricting rings, adhesive branches and adhesive knobs are restricted to the upper litter and humus layers. The net forming predators and endoparasites are isolated at all depths, although they are significantly more abundant in the lower mineral rich soils. A much greater species diversity of nematophagous fungi is recorded in the upper organic zones.Preliminary soil analysis indicates thatCephalosporium balanoides is independent of all soil variables, while predators able to form traps spontaneously are restricted to the organic soils which are rich in nematodes. Non-spontaneous trap forming predators, which are excellent saprophytes, are isolated from the deeper soils which are low in nutrients. The ecological significance of these results is discussed.     

Zebra stripes and tiger stripes: the spatial frequency distribution of the pattern compared to that of the background is significant in display and crypsis

Some striped animals are camouflaged in their natural environment, whereas others are conspicuous. Mammals are known to have spatial frequency analysers in their visual mechanism, and it is suggested that the spatial characteristics of a striped pattern are different in camouflaged and conspicuous animals. Fourier analysis of the stripes of the zebra shows spatial frequencies in the pattern that are unlikely to be present so strongly in their natural background scene. A similar analysis of the camouflaging stripes of a tiger show that the distribution of spatial frequencies are similar to that in the background scene.     

Sandstone rockhouses of the eastern United States,with particular reference to the ecology and evolution of the endemic plant taxa

Rockhouses are semicircular recesses extending far back under cliff overhangs that are large enough to provide shelter for humans. The largest sandstone rockhouses in the eastern United States are at the heads of gorges, and they are in stream valleys cut during the Pleistocene; most are formed in Mississippian and Pennsylvanian-age rocks. Compared to the surrounding environment, the interior of rockhouses is shaded, is warmer during winter and cooler during summer, and has lower evaporation rates and higher humidities. Water enters rockhouses primarily by groundwater seepage and by dripping from the ceiling. Soil consists mostly of sand with low pH, but high levels of some nutrients are associated with saltpeter earth and with ecofactual and artifactual remains left by human occupants during prehistoric time. Most plant taxa in sandstone rockhouses in eastern United States are native C₃ phanerophytes or hemicryptophytes, and similarities in species composition among rockhouses are low. Eleven plant taxa belonging to eight families of flowering plants and ferns are endemic or nearly endemic to sandstone rockhouses in eastern United States. Three endemics are restricted to the gorges of a single river, and only one taxon ranges far north of the Wisconsinan Glacial Boundary. The endemic ferns are Tertiary relicts derived from tropical taxa. The majority of endemic flowering plants are derived from temperate taxa that grow in habitats in the vicinity of rockhouses; their relative age ranges from Late Tertiary to the Recent. All the endemic taxa are perennial; two ferns occur as independent gametophytes. The endemic taxa of rockhouses are threatened primarily by disturbances associated with recreation.     

Schistosoma mansoni: a comparison of male and female muscle physiology

Surface electrical activity and membrane potentials recorded from male and female Schistosoma mansoni are similar. Surface electrical activity and responses to electrical stimulation are slightly higher in females. Contractures induced by praziquantel, 60 mM K+, ouabain or 5 degrees C are slightly less in females but responses to putative neurotransmitters (5-HT, dopamine and carbachol) are the same in both sexes. Females are more susceptible to the removal of Ca2+ and to the increase of Mg2+ in the medium. These differences may be due to anatomical differences in the sexes or to the recording methods used.     

桂西北典型喀斯特区生态服务价值的环境响应及其空间尺度特征

Study on ecosystem service values (ESVs) is the bridge of understanding ecosystem and economic decision-making. To investigate the response of ESVs to ambient environment and their spatial scales is an urgent work in the process of ecological restoration and sustainable development in southwest China. Based on the previous research results, the remote images, and weather data of 31 years (1975-2005), the response of ESVs to ambient environment and their spatial scales in a typical karst area of northwest Guangxi, China were evaluated with the method of empirical mode decomposition (EMD) in this paper. The results showed that ESVs had obvious variations with changes in elevation, rocky types and soil types, and had corresponding characteristics of spatial scales. The ESVs in middle and low elevation areas were higher, but they decreased due to human activities such as deforestation. The ESVs in peak-cluster depression areas were lower, and they would increase as influenced by policies such as returning farmland to forestland. The ESVs were influenced by rocky types, showing lower values but an increasing trend in the typical karst regions while higher values but a decreasing trend in non-karst regions. The average ESVs in the west part of the study region, which is not only the main nature reserve for rare wildlife species in Guangxi, but also one of the best preserved natural vegetation regions in China, were more than 15,000 RMB Yuan ha-1,. Comparatively, the ESVs were less than 10,000 Yuan ha-1 in the middle part of the region attributed to low vegetation coverage, serious peak-cluster depression and karst rocky desertification. After about 20 years, that is from 1985 to 2005, the ecosystem conditions had been improved and the ESVs had increased in the middle and eastern part of this study region. On the contrary, in most western part, which was dominated by subtropical evergreen broad-leaved forest, they had been worsened, and the balance values of ESVs were negative. As for the relationships of ESVs with rocky types and soil types, lime soil and red soil were the two main soil types that contributed to ESVs (The total contribution was above 60%, and it is 63.77%,64.37%,64.56%,64.91% respectively in the four years of 1985, 1990, 2000 and 2005.). The variance contribution of intrinsic mode function (IMF) and trend (R) showed that there were obvious special sales for ESVs in this study area, and the main spatial scales were about 2.7 km, 5.5 km, and 11.6 km. The variance contribution ratio was 12.29%, 11.26%, 11.49% respectively, and the trend (R) was high (17.74%). In conclusion, this study indicated that ecosystem conditions in the typical karst area were improved owing to the application of rocky desertification control policies, such as ecological migration and returning farmland to forestland. Besides, the main spatial scales of ESVs in the study area were the interactions of terrain, physiognomy, land use / land cover and human activities.     

Physiologic inhibitors of blood coagulation. 2. Alpha 2-macroglobulin, alpha-antitrypsin and the C1 inhibitor of complement

Three physiological inhibitors of blood coagulation - alpha-2-macroglobulin, alpha-1-antitrypsin, and C-1-inhibitor of complement - are dealt with in a brief survey. The point is that these are proteins of the organism with a defence character which are also able to inhibit an extraordinarily broad spectrum of proteases. Some recent findings about their molecular structure, manner of response, and inhibitory spectrum are represented. Comparisons are made to corresponding proteins in mammals, in alpha-2-macroglobulin and even in lower vertebrates. Moreover, the inherited deficiency of these three inhibitors are represented with respect to human diseases and changes of their blood level in the course of various diseases are referred to.     

中国缩颜蚜蝇族种类记述及地理分布(双翅目:食蚜蝇科)

本文记述了我国双翅目食蚜蝇科缩颜蚜蝇族6属23种,其中有5新种2新纪录属13新纪录种,列出了属、种检索表,并对新种进行了形态描述,同时,对此族的地理分布、区系及起源进行了初步探讨。     

The family Erinaceidae: a synthesis of its taxonomy, phylogeny, ecology and zoogeography

All species and higher taxa of Recent Erinaceidae are diagnosed, the character-states most useful in classification are tabulated and the most probable phylogenies presented. Four African species are included in the genus Atelerix. The desert-adapted Paraechinus is believed to be more closely related to Atelerix than to the convergent Hemiechinus. The ranges of all species are mapped, with emphasis upon areas of parapatry and sympatry. Marginal localities are listed if they are not derived from previously published maps. All nominal fossil species that have been allocated to Recent genera are listed. Ecological data relevant to the interpretations of species boundaries, e.g. relating to diet and habitat, are summarized, and the factors likely to determine the species boundaries are reviewed.     

Bioinformatics classification and functional analysis of PhoH homologs

PhoH protein is a putative ATPase belonging to the phosphate regulon in Escherichia coli. EC-PhoH homologs are present in different organisms, but it is not clear if they are functionally related, besides nothing is known about their regulation. To distinguish true functional orthologs of EC-PhoH in different classes of bacteria and to identify their functional role in bacterial metabolic network we performed phylogenetic analysis of these proteins and comparative study of position and regulation of the related genes. Three groups of proteins were identified. Proteins of the first group (BS-PhoH orthologs) are present in most of bacteria and are proposed to be functionally linked to phospholipid metabolism and RNA modification. Proteins of the second group (BS-YlaK orthologs) are present in most of aerobes and Actinobacterial YlaK orthologs are shown to be members of a fatty acid beta-oxidation regulons. EC-PhoH orthologs are classified in a third group, specific for Enterobacteria. Functional role of PhoH homologs in the lipid and RNA metabolism and proposed interrelation of PhoH paralogs in one organism are discussed.     

Cell surface proteins and malignant transformation

Many of the altered properties of malignant cells are thought to involve alterations in cell surface functions. In order to understand these alterations it is necessary to know more about the molecular structure of the surface. Methods for analyzing surface proteins are discussed and their application to normal and transformed tissue culture cells are reviewed. A number of surface proteins are observed to be altered by transformation. Most of the alterations are reductions in amounts of particular species, although a few proteins do increase. Evidence concerning the reasons for these alterations and the possible functions of some of the molecules is reviewed. Working hypotheses arising from these data are presented and prospects for understanding the physiological changes in terms of molecular effects are discussed. Particular emphasis is placed on the idea that surface molecules are associated in specific-non-covalent complexes which are important for their functions.     

Cellular lipid dynamics

During the past years, the notion of microdomains at the surface of cellular membranes has been developed. These are constituted by lipid rafts which involve sphingoglycolipids and cholesterol. To these rafts are associated proteins which have a lipid anchor or are transmembrane proteins. These lipid rafts target specific proteins at the plasma membrane surface and can remain associated with them. They are present in surface receptors and endocytosis occurs upon binding of the specific ligands. Thus these rafts participate to major aspects of cellular dynamics. These rafts are complex structures, insoluble in non-ionic detergents. According to the detergent used, many types of rafts can be isolated. Any alteration of cholesterol, sphingoglycolipids, or abnormalities of the proteins themselves, can lead to abnormal targeting at the membrane surface. It is possible that specific sphingoglycolipids are necessary to target specific proteins at the membrane surface. This may explain the complexity of the sphingoglycolipid molecules, both in relation to their oligosaccharide and to their ceramide structures. There is both a cellular and a tissue specificity of these constituents. Complex sphingoglycolipids are involved in cellular differentiation, cellular polarization, and modified in relation to cancer. Virus and bacteria can be linked to the sphingoglycolipids of these microdomains and alter cellular signaling and function. Sphingoglycolipids are involved in autoimmune diseases as antibody targets and in neurolipidoses which are genetic diseases involving their catabolism. The dynamics of the lipid rafts, in relation to cholesterol, can be altered in Niemann-Pick's disease type C and in Alzheimer's disease. Thus these microdomains are involved in many aspects related to normal and pathological cellular dynamics.     

ELECTRON MICROSCOPIC STUDIES OF MITOSIS IN AMEBAE : II. The Giant Ameba Pelomyxa carolinensis

Dividing nuclei from the giant ameba Pelomyxa carolinensis were fixed in osmium tetroxide solutions buffered with veronal acetate to pH 8.0. If divalent cations (0.002 M calcium, magnesium, or strontium as chlorides) were added to the fixation solution, fibrils that are 14 mµ in diameter and have a dense cortex are observed in the spindle. If the divalent ions were omitted, oriented particles of smaller size are present and fibrils are not obvious. The stages of mitosis were observed and spindle components compared. Fibrils fixed in the presence of calcium ions are not so well defined in early metaphase as later, but otherwise have the same diameter in the late metaphase, anaphase, and early telophase. Fibrils are surrounded by clouds of fine material except in early telophase, when they are formed into tight bundles lying in the cytoplasm unattached to nuclei. Metaphase and anaphase fibrils fixed without calcium ions are less well defined and are not observably different from each other. The observations are consistent with the concept that spindle fibrils are composed of polymerized, oriented protein molecules that are in equilibrium with and bathed in non-oriented molecules of the same protein. Partially formed spindle fibrils and ribosome-like particles were observed in the mixoplasm when the nuclear envelope had only small discontinuities. Remnants of the envelope are visible throughout division and are probably incorporated into the new envelope in the telophase. Ribosome-like particles are numerous in the metaphase and anaphase spindle but are not seen in the telophase nucleus, once the envelope is reestablished, or in the interphase nucleus.     

Filariae of rodents useful for the experimental study of human onchocerciasis

In order to obtain skin and ocular lesions comparable to those which are found in human onchocerciasis, it is not necessary to use members of the genus Onchocerca which are found in large animals and difficult to use. Other Filariae with biological features comparable to Onchocerca volvulus can be used in which microfilariae are localized in capillaries and can escape from the walls and produce lesions similar to those in onchocerciasis. The life cycles of several filariae of rodents have been worked out and they are proposed as experimental models as the tick vectors and the rodent hosts are easily maintained in the laboratory.     

宁波北仑植物资源及珍稀保护植物研究

宁波市北仑区蕴藏着丰富的植物资源,据调查有野生维管植物158科454属712种,在这些植物中,有药用植物276种、用材树种95种、观赏植物87种、纤维植物60种、防护植物55种、薪炭植物52种、油脂植物48种、饲料植物42种、野生水果38种、芳香植物30种、淀粉植物25种、蜜源植物24种、野菜植物18种等,大多具有开发和可持续利用的价值;此外,北仑还有国家野生重点保护植物4科5属5种、古树名木15科17属17种,这些植物对开发建设中的北仑来说,是极其宝贵的自然资源.因此,为使北仑区的植物资源得到可持续的利用,对其开发利用和保护提出了建议.     

Are plants really larger in their introduced ranges?

The "rule" that individuals of nonindigenous plant species are larger where they are introduced than where they are native is not borne out in detailed comparisons of European species introduced to California or the Carolinas and species from California and the Carolinas introduced to Europe. On average, individuals of California species are taller in California than in Europe, while individuals of species native to Europe do not differ between Europe and California. Similarly, individuals of species from the Carolinas are, on average, taller in the Carolinas than in Europe, while individuals of European species are the same height in Europe and the Carolinas or, depending on the nature of the statistical analysis, taller in Europe. Results for herbaceous species only are substantially the same. Although there is no general tendency for species to be taller in their introduced ranges, many species are, in fact, taller in some regions where they are introduced than in their native ranges. Absence of natural enemies in the introduced range is one hypothesis for such observations, but other hypotheses are possible, and the specific reasons for height differences must be sought case by case. The absence of a general tendency casts doubt on the biological control strategy of introducing sequences of phytophages, none of which delivers a knockout blow to a weed, with the expectation that each successive phytophage will force the plant to devote more resources to defense and fewer to traits such as increased size that make it more competitive.     

江苏宜兴森林自然保护区种子植物区系特点及植被性质

对江苏宜兴森林自然保护区及周边地区的种子植物区系成分进行统计分析,归为４大类１５个分布类型。属的成分以温带比例最高（６１％）,东部成分亦较明显（２５％）,中西部成分极少,几无本地特有成分,属较典型的华东植物区系地区。对该地区现存植物进行计算分析,结合栽培植物及古植被资料,得出以青冈〔Ｃｙｃｌｏｂａｌａｎｏｐｓｉｓｇｌａｕｃａ（Ｔｈｕｎｂ．）Ｏｅｒｓｔ．〕、石栎〔Ｌｉｔｈｏｃａｒｐａｇｌａｂｅｒ（Ｔｈｕｎｂ．）Ｎａｋａｉ〕等为建群种的中亚热带常绿阔叶林是本地区的地带性植被。自然保护区建立（１９８１）以后植被恢复明显,许多样地已接近自然植被。