FERN SECTION IN CUlZHOU BOTANICAL GARDEN

With the devcioprnent of economics and owing to certain factors of plants themselves,some ferns arc in a dangcrous situation. It is necessary to set up a fern section or fernaripm in Guizhou as a gene pool mainly for subtropical ferns, which can not be replaced by the hcrbariurn or natural preserve. A fern section in Guizhou Botanical Garden has been established, It's composed of a 3-are fern garden,a grccnhouse and a shed. 300 taxa of rems and fern aUics from Guizhou and East, South,North east, and South west patts in China have bccn gathered in recent 5 years. Another 3-year project supported by the National Natural Science Foundation of China (NSFC) is carded on for morc fern introduction. It will be not only for thc conservation of the rare and/or endangered pteridophytes, but as a base for fern researching, teaching, scientific propagating and exploiting.Practice shows that Guiyang, the capital of' Guizhou, is one of the ideal places for fern introduction and conscrvation in China.     

Uptake of aflatoxin B1 by the skin of rats

Zusammenfassung Nachweis der Absorption von Aflatoxin B₁ durch die Rattenhaut. Die toxische Leberwirkung nach der Hautbepinselung entsprach den von anderen Autoren gefundenen Verhältnissen bei peroraler oder intraperitonealer Verabreichung.     

Changes observed in the FSH and LH cells of the adenohypophysis ofPresbytis entellus entellus following cadmium induced testicular necrosis

Zusammenfassung Da Kadmium schwere Schädigungen im Hoden hervorrufen kann, wurde die Adenohypophyse bei 14 männlichenPresbytis entellus entellus nach testikulärer Nekrose untersucht. Die verschiedenen Zellen der Adenohypophyse zeigen unterschiedliche Reaktionen, zum Teil mit Vakuolen und Granulationen. Nach Ablauf eines Jahres wird eine Erholung solcher Zellen beobachtet mit gleichzeitiger Regeneration des Hodenepithels und der Zwischenzellen.

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This work was supported by a grant from the Ford Foundation.     

An extreme distortion of the Van Allen belt arising from the 'Hallowe'en' solar storm in 2003

The Earth's radiation belts--also known as the Van Allen belts--contain high-energy electrons trapped on magnetic field lines. The centre of the outer belt is usually 20,000-25,000 km from Earth. The region between the belts is normally devoid of particles, and is accordingly favoured as a location for spacecraft operation because of the benign environment. Here we report that the outer Van Allen belt was compressed dramatically by a solar storm known as the 'Hallowe'en storm' of 2003. From 1 to 10 November, the outer belt had its centre only approximately 10,000 km from Earth's equatorial surface, and the plasmasphere was similarly displaced inwards. The region between the belts became the location of high particle radiation intensity. This remarkable deformation of the entire magnetosphere implies surprisingly powerful acceleration and loss processes deep within the magnetosphere.     

A universal scaling relation in high-temperature superconductors

Since the discovery of superconductivity at elevated temperatures in the copper oxide materials there has been a considerable effort to find universal trends and correlations amongst physical quantities, as a clue to the origin of the superconductivity. One of the earliest patterns that emerged was the linear scaling of the superfluid density (rho(s)) with the superconducting transition temperature (T(c)), which marks the onset of phase coherence. This is referred to as the Uemura relation, and it works reasonably well for the underdoped materials. It does not, however, describe optimally doped (where T(c) is a maximum) or overdoped materials. Similarly, an attempt to scale the superfluid density with the d.c. conductivity (sigma(dc)) was only partially successful. Here we report a simple scaling relation (rho(s) proportional, variant sigma(dc)T(c), with sigma(dc) measured at approximately T(c)) that holds for all tested high-T(c) materials. It holds regardless of doping level, nature of dopant (electrons versus holes), crystal structure and type of disorder, and direction (parallel or perpendicular to the copper-oxygen planes).     

Cytochrome c release and endoplasmic reticulum stress are involved in caspase-dependent apoptosis induced by G418

G418 is used extensively in transfection experiments to select eukaryotic cells that have acquired neomycin resistance genes, but the mechanism is still elusive. To investigate this, we treated normal rat kidney cells with G418 for 3 days and found that the cells presented typical apoptotic features such as cell shrinkage, nuclear fragmentation, and caspase-3 activation. However, there was no low-molecular DNA ladder. The pan caspase inhibitor z-VAD-fmk completely inhibited this type of apoptosis, suggesting a caspase-dependent mechanism. Caspase cascades in apoptosis induced by G418 were initiated by at least two pathways: the release of cytochrome c from mitochondria, which was observed under confocal microscopy, and endoplasmic reticulum stress, demonstrated by the increase in Ca²⁺ concentration and the cleavage of m-calpain and procaspase-12. Both pathways activated caspase-9. Inhibition of caspase-9 activity by z-LEHD-fmk prevented most of the cells from apoptosis, and E-64d, an inhibitor of calpain accentuated this block. The cleavage of casapse-9 and caspase-12 was blocked only by simultaneous application of z-VAD-fmk and E-64d, but not by either alone. E-64d did not prevent the release of cytochrome c. These results indicated that these two pathways were independent of each other. Received 1 April 2004; received after revision 21 April 2004; accepted 26 May 2004     

Animal virus replication and RNAi-mediated antiviral silencing in Caenorhabditis elegans

The worm Caenorhabditis elegans is a model system for studying many aspects of biology, including host responses to bacterial pathogens, but it is not known to support replication of any virus. Plants and insects encode multiple Dicer enzymes that recognize distinct precursors of small RNAs and may act cooperatively. However, it is not known whether the single Dicer of worms and mammals is able to initiate the small RNA-guided RNA interference (RNAi) antiviral immunity as occurs in plants and insects. Here we show complete replication of the Flock house virus (FHV) bipartite, plus-strand RNA genome in C. elegans. We show that FHV replication in C. elegans triggers potent antiviral silencing that requires RDE-1, an Argonaute protein essential for RNAi mediated by small interfering RNAs (siRNAs) but not by microRNAs. This immunity system is capable of rapid virus clearance in the absence of FHV B2 protein, which acts as a broad-spectrum RNAi inhibitor upstream of rde-1 by targeting the siRNA precursor. This work establishes a C. elegans model for genetic studies of animal virus-host interactions and indicates that mammals might use a siRNA pathway as an antiviral response.     

Metallothionein expression in the central nervous system of multiple sclerosis patients

Multiple sclerosis (MS) is a major chronic demyelinating and inflammatory disease of the central nervous system (CNS) in which oxidative stress likely plays a pathogenic role in the development of myelin and neuronal damage. Metallothioneins (MTs) are antioxidant proteins induced in the CNS by tissue injury, stress and some neurodegenerative diseases, which have been postulated to play a neuroprotective role. In fact, MT-I+II-deficient mice are more susceptible to developing experimental autoimmune encephalomyelitis (EAE), and treatment of Lewis rats with Zn-MT-II reduces EAE severity. We show here that, as in EAE, MT-I+II proteins were expressed in brain lesions of MS patients. Cells expressing MT-I+II were mainly astrocytes and activated monocytes/macrophages. Interestingly, the levels of MT-I+II were slightly increased in the inactive MS lesions in comparison with the active lesions, suggesting that MTs may be important in disease remission.