Pollen morphology of the genus Cornukaempferia （Zingiberaceae） in Thailand

Cornukaempferia is a recently described genus of Zingiberaceae which only occurs in Thailand as a rare genus with limited geographical distribution. Only three species have been described so far, including a recently described new species, C. larsenii. These three species are morphologically very similar and additional data on other biological aspects are useful for the elucidation of their relationship. Pollen morphology of all three species of genus Cornukaempferia has been studied by light microscopy and scanning electron microscopy. The pollen grains are monad, spherical, inaperturate. The exine sculpture is echinate with psilate between the spines for C. aurantiflora and C. longipetiolata, or echinate with regulate between the spines for C. larsenii. This observation helps support the taxonomic status of C. larsenii.     

TOXOPLASMOSIS—The Protean Manifestations of the Condition and Their Significance in Pregnancy and in Newborn Infants

Toxoplasmosis is a relatively common and generally mild parasitic infection which can, however, produce fatal and crippling complications under certain conditions — particularly when a human fetus or a newborn infant is infected. In this instance, the infection is the result of a spread of the acquired disease which may occur in the mother in the last six months of pregnancy. Although the infection of adults can be dangerous and fatalities have been reported, the danger to the nervous system, eyes and other structures of the newborn infant can be devastating—blindness, brain damage and mental deficiency, particularly as the result of an obstruction to the flow of circulating cerebrospinal fluid within the brain.This report covers a number of differing features of the disease which have been described separately by other authors in specialty journals and in the foreign literature. If present, these signs should suggest toxoplasmosis, particularly in pregnancy, in the newborn infant and in still-born infants.Early diagnosis is of paramount interest in view of the poor response which may be obtained in the treatment of subacute and chronic phases of the illness. Difficulties in diagnosis stem from the manifestations of toxoplasmosis which closely resemble the symptoms of other infectious diseases.The clinical laboratory diagnosis is made by the isolation of the organism or by the demonstration of immune protein in the patient''s serum.     

Nucleases of the Metallo-β-lactamase Family and Their Role in DNA and RNA Metabolism

ABSTRACT

Proteins of the metallo-β-lactamase family with either demonstrated or predicted nuclease activity have been identified in a number of organisms ranging from bacteria to humans and has been shown to be important constituents of cellular metabolism. Nucleases of this family are believed to utilize a zinc-dependent mechanism in catalysis and function as 5′ to 3′ exonucleases and or endonucleases in such processes as 3′ end processing of RNA precursors, DNA repair, V(D)J recombination, and telomere maintenance. Examples of metallo-β-lactamase nucleases include CPSF-73, a known component of the cleavage/polyadenylation machinery, which functions as the endonuclease in 3′ end formation of both polyadenylated and histone mRNAs, and Artemis that opens DNA hairpins during V(D)J recombination. Mutations in two metallo-β-lactamase nucleases have been implicated in human diseases: tRNase Z required for 3′ processing of tRNA precursors has been linked to the familial form of prostate cancer, whereas inactivation of Artemis causes severe combined immunodeficiency (SCID). There is also a group of as yet uncharacterized proteins of this family in bacteria and archaea that based on sequence similarity to CPSF-73 are predicted to function as nucleases in RNA metabolism. This article reviews the cellular roles of nucleases of the metallo-β-lactamase family and the recent advances in studying these proteins.     

Studies of Mycorrhizal Fungi of Chinese Orchids and Their Role in Orchid Conservation in China—A Review

China has over 1,200 species of native orchids in nearly 173 genera. About one fourth of native species are of horticultural merit. Some species are of Chinese medicinal value. In fact, the demand on orchid species with high Chinese medicinal values such as Gastrodia elata, Dendrobium offcinale, along with demands on species of cultural importance, such as those in the genus of Cymbidium, is a major factor causing wild populations to diminish and in some cases, drive wild populations to the brink of extinction. These market demands have also driven studies on the role of mycorrhizal fungi in orchid seed germination, seedling and adult growth, and reproduction. Most of these mycorrhizal studies of Chinese orchids, however, are published in Chinese, some in medical journals, and thus overlooked by the mainstream orchid mycorrhizal publications. Yet some of these studies contained interesting discoveries on the nature of the mycorrhizal relationships between orchids and fungi. We present a review of some of these neglected publications. The most important discovery comes from the mycorrhizal studies on G. elata, in which the researchers concluded that those fungi species required to stimulate seed germination are different from those that facilitate the growth of G. elata beyond seedling stages. In addition, presence of the mycorrhizal fungi associated with vegetative growth of post-seedling G. elata hindered the germination of seeds. These phenomena were unreported prior to these studies. Furthermore, orchid mycorrhizal studies in China differ from the mainstream orchid studies in that many epiphytic species (in the genus of Dendrobium, as medicinal herbs) were investigated as well as terrestrial orchids (mostly in the genus Cymbidium, as traditional horticultural species). The different responses between epiphytic and terrestrial orchid seeds to fungi derived from roots suggest that epiphytic orchids may have a more general mycorrhizal relationship with fungi than do terrestrial orchid species during the seed germination stage. To date, orchid mycorrhizal research in China has had a strongly commercial purpose. We suggest that this continuing research on orchid mycorrhizal relationships are a solid foundation for further research that includes more rare and endangered taxa, and more in-situ studies to assist conservation and restoration of the endangered orchids. Knowledge on the identities and roles of mycorrhizal fungi of orchids holds one of the keys to successful restoration and sustainable use of Chinese orchids.     

Pollen Morphology of Parnassia L. （Parnassiaceae） and Its Systematic Implications

The pollen morphology of 28 species of Parnassia L. was investigated with light microscopy and scanning electron microscopy (SEM). The shape of pollen grains in this genus varies from subspheroidal to prolate in equatorial view and is three-lobed circular in the polar view. Pollen grains are usually radially symmetrical, isopolar, tricolporate or syntricolporate, with reticulate sculpture. The pollen characteristics among species are fairly similar to each other. Morphological information regarding the pollen grains shows that Parnassia is a natural genus. Based on exine ornamentation observed under SEM, three types of pollen grains were recognized: (i) type I, with foveolate-reticulate sculpture; (ii) type II, with a finely reticulate sculpture; and (iii) type III, with a coarsely reticulate sculpture. Most sections of this genus have one type of sculpture of pollen morphology, but Sect. Nectarotrilobos has three types of sculpture and Sect.Saxifragastrum has two types of sculpture. All three types of sculpture can be found in Southwest China,with species with the longest (Parnassia delavayi Franch.) and shortest (Parnassiafaberi Oliv.) colpi,implying that Southwest China is the center of diversification of the genus.     

The pseudoplanktonic crinoid Traumatocrinus from the Late Triassic of Southwest China — Morphology,ontogeny, and taphonomy

The morphology of the pseudoplanktonic crinoid Traumatocrinus from the early Late Triassic (Carnian) Xiaowa Formation of Guanling County (South China, Guizhou Province) is described based on articulated and disarticulated material. Juvenile individuals of less than 10 mm crown height with 20 isotomously branching arms prove the encrinid ancestry of the family Traumatocrinidae. However, even the smallest individuals have five large interradials. Endotomous branching commences at crowns of slightly more than 10 mm at the outer arms of the rays. All brachial articulations are ligamentary (granosyzygies). The assignment of the Chinese material to one of the nominal species of Traumatocrinus is still left open. The diagnosis of the genus Traumatocrinus is emended. Traumatocrinus lived attached to driftwood and was widespread across the Palaeo-Tethys. In contrast to its benthic encrinid ancestors, Traumatocrinus fixed its distal column with countless anastomosing radicular cirri to its substrate, preferentially to the ends of the driftwood logs. Depending on the state of the hypothesized mutable collagene tissue, the columns are preserved in straight positions or curved like a rope. Crowns are preserved in star position with radially splayed arms or in lateral bell position with the cup disrupted in interbrachial position. As usual in black shales, the exposed upper sides of the crinoids are in a more or less progressive state of decomposition whereas the embedded lower sides are intact.     

Trend Patterns of Vegetative Coverage and Their Underlying Causes in the Deserts of Northwest China over 1982 – 2008

We identified the spatiotemporal patterns of the Normalized Difference Vegetation Index (NDVI) for the years 1982–2008 in the desert areas of Northwest China and quantified the impacts of climate and non-climate factors on NDVI changes. The results indicate that although the mean NDVI has improved in 24.7% of the study region; 16.3% among the region has been stagnating in recent years and only 8.4% had a significantly increasing trend. Additionally, 45.3% of the region has maintained a stable trend over the study period and 30.0% has declined. A multiple regression model suggests that a wetter climate (quantified by the Palmer Drought Severity Index, PDSI) is associated with higher NDVI in most areas (18.1% of significance) but these historical changes in PDSI only caused an average improvement of approximately 0.4% over the study region. Contrasting the regression results under different trend patterns, no significant differences in PDSI impacts were detected among the four trend patterns. Therefore, we conclude that climate is not the primary driver for vegetative coverage in Northwest China. Future studies will be required to identify the impacts of specific non-climatic factors on vegetative coverage based on high-resolution data, which will be beneficial in creating an effective strategy to combat the recent desertification trend in China.     

Morphology and distribution of Müller cells in the retina of the toad Bufo marinus

We have previously shown that an antibody against neuron-specific enolase (NSE) selectively labels Müller cells (MCs) in the anuran retina (Wilhelm et al. 1992). In the present study the light- and electron-microscopic morphology of MCs and their distribution were described in the retina of the toad, Bufo marinus, using the above antibody. The somata of MCs were located in the proximal part of the inner nuclear layer and were interconnected with each other by their processes. The MCs were uniformly distributed across the retina with an average density of 1500 cells/mm². Processes of MCs encircled the somata of photoreceptor cells isolating them from each other by glial sheath, except for those of the double cones. Some of the photoreceptor pedicles remained free of glial sheath. Electron-microscopic observations confirmed that MC processes provide an extensive scaffolding across the neural retina. At the outer border of the ganglion cell layer these processes formed a non-continuous sheath. The MC processes traversed through the ganglion cell layer and spread beneath it between the neuronal somata and the underlying optic axons. These processes formed a continuous inner limiting membrane separating the optic fibre layer from the vitreous tissue. Neither astrocytic nor oligodendrocytic elements were found in the optic fibre layer. The significance of the uniform MC distribution and the functional implications of the observed pattern of MC scaffolding are discussed.     

Singing the Popular Songs? Nightingales Share More Song Types with Their Breeding Population in Their Second Season than in Their First

Signals used in communication often change throughout an individual’s life course. For example, in many song bird species, males modify their song especially between their first and second breeding season. To address one possible reason of such modification, we investigated whether common nightingales Luscinia megarhynchos adjust their song type repertoires to sing the song types commonly occurring in their breeding population. We analysed nocturnal singing of six nightingales in their first and second breeding season and compared their repertoire composition and usage to the ‘typical’ repertoire and usage on the breeding ground (represented by seven reference birds). Songs that were maintained between the first and second season by the six focal birds occurred in most of the repertoires of the seven reference birds and were sung often. In contrast, song types that were dropped from the repertoires occurred less often in the reference birds’ repertoires and were sung less often. Furthermore, in the first year, each focal nightingale’s repertoire was less similar to the reference birds’ repertoires than in the second year. Thus, nightingales adjusted their singing towards the songs popular in the breeding grounds by keeping song types that were common and frequently sung by other individuals in their breeding area and by disposing of infrequently performed ones. This resulted in increased similarity with the population’s repertoire from the first to the second year. We discuss possible ontogenetic processes that may lead to such an adjustment and suggest an improved ability to match song types as possible adaptive value.     

Types of phytomass — and leaf area index profiles in grassland vegetation

Various types of grasslands in the Netherlands were catagorized by their structure: phytomass and leaf area were measured in arbitrarily chosen vegetation layers with width intervals of 2.5, 5, 10 or 20 cm, depending on the height of the sward. Data were standardized for fixed width of layers (layer width set), and for equal numbers of layers of varying width (layer number set). Data were clustered by Ward's method as well as ordinated by Principal Components Analysis (PCA). The cluster method revealed 6 groups; those of the layer number sets could be contrasted in their vertical built-up of leaf area index (LAI) — and phytomass profiles and could be characterized ecologically. The ordinations confirmed the findings of the cluster analyses. In our data grassland structure varied mainly along a gradient from constant and sufficient to strongly varying soil water supply during the growing season, and a gradient in soil nutrients from rich to poor. Sites with constant water supply appeared more often nutrient-rich and those with a varying water supply more often poor in nutrients.Nomenclature of syntaxa follows Westhoff & Den Held (1969).Acknowledgements: Financial support for this study was obtained from the Foundation for Fundamental Biological Research (BION) under grant nr. 14.75.18. We thank R. K. Peet and M. P. Austin for their useful comments.Dedicated to Prof. H. F. Linskens (Nijmegen) on the occasion of his 65th birthday.     

BRAIN-DAMAGED CHILDREN—The Problem of Relations in the Family Group

Children with minimal brain damage show a characteristic pattern of behavior.Often there are no physical signs of abnormality, but the diagnosis can be made from the history, electroencephalographic tracings, psychologic tests and repeated observations.The behavior is a composite of the effects of the brain damage and the response of the child to his environment. The behavior of the brain-damaged child is frequently so frustrating to parents that attitudes of rejection, withdrawal or excessive punitive measures occur.In the present study, when drugs were given and the child''s behavior improved, the parents were better able to understand the needs of the child and create a better home environment in which there was less frustration and emotional pressure.     

THE INSECTICIDES—Their Hazard in Industry and in the Home Part I—Chemistry and Pharmacology

Chemical, pharmacologic and toxicologic properties of the chlorinated hydrocarbon and organic phosphate insecticides have been reviewed. The chlorinated group present problems if there is either acute or chronic exposure, whereas the problems associated with the organic phosphates develop only in event of acute exposure.Chlorinated hydrocarbon insecticides accumulate in body fat depots and cause both liver and kidney damage while being metabolized and excreted. Organic phosphates destroy cholinesterase and produce effects related to overstimulation of the cholinergic branch of the autonomic nervous system. Barbiturates control the convulsions produced by the chlorinated hydrocarbon insecticides. Atropine blocks most of the effects of the organic phosphate insecticides. These compounds may be grouped in the following order of decreasing toxicity: TEPP, HETP, parathion, OMPA, ENP, aldrin, chlorophenothane, toxaphene, gamma benzene hexachloride, malathon and chlordane.