Plasmodium durae Herman from the introduced common peafowl in northern Nigeria

Plasmodium (Giovannolaia) durae Herman was originally described from Kenya, the type host being the common turkey, Meleagris gallopavo Linnaeus. There are no field records of this association outside of Africa, where the parasite, herein reported from another introduced and domesticated bird (the common peafowl, Pavo cristatus Linnaeus), was recently listed from 2 native Phasianidae of the genus Francolinus. The justification for the present identification is submitted against background data concerning malaria parasites from turkeys and other Galliformes in Africa and elsewhere, and restraint is urged in describing yet more "new species" of avian Plasmodium belonging to morphologically close taxa within Novyella and Giovannolaia. A near relative of P. durae, Plasmodium dissanaikei de Jong, is transferred from the former subgenus to the latter one.     

西双版纳野生绿孔雀种群数量及分布现状调查

绿孔雀（Ｐａｖｏｍｕｔｉｃｕｓ）在世界共３个亚种,其中Ｐ．ｍｕｔｉｃｕｓｉｍｐｅｒａｔｏｒ主要分布于我国云南、缅甸东部、泰国和印度等地［１～３］。三十多年前,在西双版纳的大部分地区均有该种的分布,是有名的“孔雀之乡”［４］。随着人类经济活动的影响,云...     

绿孔雀在中国的分在现状调查

绿孔雀在中国现仅见于云南西部、中部和南部,通过１９９１年至１９９３年的调查,绿孔雀现存数量较多的地区有云南省瑞丽县、陇川县、昌宁县、永德县、新平县、普洱县、墨江县、景东县、楚雄市、双柏县、南华县。过去有分布记录现已绝迹或濒临绝迹的地区有盈江县、沪水县、腾冲县、蒙自县、河口县。永仁县的中和、直左为新近发现的分布点,据当地群众反映,在维西县的叶枝,德钦县的拖顶和奔子栏也发现绿孔雀。由于栖息地生境的破坏,导致绿孔雀现存种群形成小家族群点状隔离分布。据估计,中国现存野生种群数量约为８００～１１００只。     

Genetic Polymorphisms in Plasmodium vivax Dihydrofolate Reductase and Dihydropteroate Synthase in Isolates from the Philippines,Bangladesh, and Nepal

Genetic polymorphisms of pvdhfr and pvdhps genes of Plasmodium vivax were investigated in 83 blood samples collected from patients in the Philippines, Bangladesh, and Nepal. The SNP-haplotypes of the pvdhfr gene at the amino acid positions 13, 33, 57, 58, 61, 117, and 173, and that of the pvdhps gene at the positions 383 and 553 were analyzed by nested PCR-RFLP. Results suggest diverse polymorphic patterns of pvdhfr alone as well as the combination patterns with pvdhps mutant alleles in P. vivax isolates collected from the 3 endemic countries in Asia. All samples carried mutant combination alleles of pvdhfr and pvdhps. The most prevalent combination alleles found in samples from the Philippines and Bangladesh were triple mutant pvdhfr combined with single mutant pvdhps allele and triple mutant pvdhfr combined with double wild-type pvdhps alleles, respectively. Those collected from Nepal were quadruple mutant pvdhfr combined with double wild-type pvdhps alleles. New alternative antifolate drugs which are effective against sulfadoxine-pyrimethamine (SP)-resistant P. vivax are required.     

Common reed produces starch granules at the shoot base in response to salt stress

Common reed (Phragmites australis) is a well known salt-tolerant plant and it is suggested that reeds recover Na(+) in the xylem sap of the shoot base (basal part of the shoot), store it temporarily in the shoot base, release it into the phloem sap, and then retranslocate it to the roots. To investigate whether Na(+) is retained in the shoot base of reeds, confocal laser scanning microscope (CLSM) observations were conducted using an intracellular Na(+)-specific fluorescent probe. The CLSM observations revealed that reeds produced a large number of the starch granules at the shoot base when salt-stressed, and that the fluorescence indicating the location of intracellular free Na(+) was observed in the same position as the starch granules. The Na content of starch granules was considerably greater than that of the shoot base, whereas the potassium (K) contents of the granules was only slightly greater than that of the shoot base. Reeds produced Na(+)-binding starch granules in the parenchyma cells of the shoot base when salt-stressed; these starch granules may decrease intracellular free Na(+). It is proposed that the site-specific production of Na(+)-binding starch granules constitutes a novel salt tolerance mechanism.     

Identification of Biochemically Distinct Properties of the Small Ubiquitin-related Modifier (SUMO) Conjugation Pathway in Plasmodium falciparum

Small ubiquitin-related modifiers (SUMOs) are post-translationally conjugated to other proteins and are thereby essential regulators of a wide range of cellular processes. Sumoylation, and enzymes of the sumoylation pathway, are conserved in the malaria causing parasite, Plasmodium falciparum. However, the specific functions of sumoylation in P. falciparum, and the degree of functional conservation between enzymes of the human and P. falciparum sumoylation pathways, have not been characterized. Here, we demonstrate that sumoylation levels peak during midstages of the intra-erythrocyte developmental cycle, concomitant with hemoglobin consumption and elevated oxidative stress. In vitro studies revealed that P. falciparum E1- and E2-conjugating enzymes interact effectively to recognize and modify RanGAP1, a model mammalian SUMO substrate. However, in heterologous reactions, P. falciparum E1 and E2 enzymes failed to interact with cognate human E2 and E1 partners, respectively, to modify RanGAP1. Structural analysis, binding studies, and functional assays revealed divergent amino acid residues within the E1-E2 binding interface that define organism-specific enzyme interactions. Our studies identify sumoylation as a potentially important regulator of oxidative stress response during the P. falciparum intra-erythrocyte developmental cycle, and define E1 and E2 interactions as a promising target for development of parasite-specific inhibitors of sumoylation and parasite replication.     

The serine repeat antigen (SERA) gene family phylogeny in Plasmodium: the impact of GC content and reconciliation of gene and species trees

Plasmodium falciparum is the parasite responsible for the most acute form of malaria in humans. Recently, the serine repeat antigen (SERA) in P. falciparum has attracted attention as a potential vaccine and drug target, and it has been shown to be a member of a large gene family. To clarify the relationships among the numerous P. falciparum SERAs and to identify orthologs to SERA5 and SERA6 in Plasmodium species affecting rodents, gene trees were inferred from nucleotide and amino acid sequence data for 33 putative SERA homologs in seven different species. (A distance method for nucleotide sequences that is specifically designed to accommodate differing GC content yielded results that were largely compatible with the amino acid tree. Standard-distance and maximum-likelihood methods for nucleotide sequences, on the other hand, yielded gene trees that differed in important respects.) To infer the pattern of duplication, speciation, and gene loss events in the SERA gene family history, the resulting gene trees were then "reconciled" with two competing Plasmodium species tree topologies that have been identified by previous phylogenetic studies. Parsimony of reconciliation was used as a criterion for selecting a gene tree/species tree pair and provided (1) support for one of the two species trees and for the core topology of the amino acid-derived gene tree, (2) a basis for critiquing fine detail in a poorly resolved region of the gene tree, (3) a set of predicted "missing genes" in some species, (4) clarification of the relationship among the P. falciparum SERA, and (5) some information about SERA5 and SERA6 orthologs in the rodent malaria parasites. Parsimony of reconciliation and a second criterion--implied mutational pattern at two key active sites in the SERA proteins-were also seen to be useful supplements to standard "bootstrap" analysis for inferred topologies.     

Preparation and characterization of subcellular fractions from the intestinal mucosa of the Northern pike (Esox lucius), with special emphasis on enzymes involved in xenobiotic metabolism

The present study was designed to prepare and characterize subcellular fractions from the intestinal mucosa of the Northern pike (Esox lucius), with special emphasis on the preparation of a microsomal fraction suitable for studying xenobiotic metabolism. The purity of the different fractions obtained by differential centrifugation, as well as the recovery of different organelles, was determined using both enzyme markers and morphological examination with the electron microscope. The subcellular distributions of several enzymes involved in drug metabolism (NADPH-cytochrome c reductase, NADH-ferricyanide reductase, epoxide hydrolase activity towards both cis- and trans-stilbene oxide as substrates, and glutathione transferase) were also examined. The subcellular distributions obtained here for drug-metabolizing and marker enzymes closely resembled those reported for rat and pike liver. The microsomal fraction obtained contained about 50% of the total endoplasmic reticulum. This fraction was relatively free of nuclei, mitochondria, Golgi, peroxisomes and cytosol, but relatively heavily contaminated with lysosomes and fragments of the plasma membrane. Within the limitations discussed, the subfractions prepared here are suitable for further characterization of drug-metabolizing systems in the intestinal mucosa of the Northern pike, as well as for other studies with this tissue.     

Isolation of Bacillus thuringiensis subsp. israelensis from diseased field-collected larvae of the saturniid moth, Hylesia metabus, in French Guiana

Abstract An isolate of Bacillus thuringiensis subsp. israelensis (BTI) was obtained from field-collected larvae of the saturniid moth, Hylesia metabus . This isolate was shown to belong to serotype H 14, and to produce a spherical parasporal body identical to that of the type strain of BTI. With an LC₅₀ of 0.764 μg cm⁻², this isolate was more toxic to H. metabus than the HD-1 strain of B. thuringiensis subsp. kurstaki (HD-1). These results demonstrate that BTI can be active against lepidopterous insects, a wider spectrum of activity than previously realized.     

Johnius (johnieops) philippinus, a new sciaenid from the philippines, with a synopsis of species included in the subgenusjohnieops

A new sciaenid,Johnius (Johnieops) philippinus, is described from the Davao Gulf, Mindanao Island Philippines. It differs from all known species of the subgenus in the combination of 29–32 dorsal fin soft rays, 5–6 scales above and 10–13 scales below the lateral line, 10–12 lower gill rakers, a broadly rounded anterior snout margin (from dorsal aspect), large eyes (28–35% HL), a narrow interorbital space (23–28% HL) and well-developed pleural ribs on 11th vertebra. A synopsis of species included in the subgenusJohnieops is provided.     

A comparison of the influence of sterols on the specific activity of the H+-ATPases in isolated plasma membrane vesicles from oat, rye and rice shoots

Plasma membrane vesicles were extracted from the shoots of 10-day-old oat, rye and rice plants and incubated with either cholesterol, stigmasterol or a mixture of sitosterol ⁺ campesterol (60:40). After ascertaining that the sterol composition of the vesicles had been altered by this treatment, the specific hydrolytic activity of the membrane-bound H⁺-ATPase (EC 3. 6. 1. 35) was measured. The results indicated that, although all sterols were taken up, cholesterol was best integrated into the plasma membrane of the species tested. After treatment, ATPase activity was altered in oat and rice, but not in rye. The results are discussed in the context of sterol/lipid and sterol/protein interactions in the plasma membrane.     

Natural acidophilous Quercus and Pinus forests in the northern Vosges,France, from a geographical perspective

Abstract. A phytosociological study of forests on Vosges sandstone in the basins of Pays de Bitche (Bitcherland) resulted in the identification of three plant communities: Luzulo-Quercetum, Leucobryo-Pinetum, and Vaccinio uliginosi-Pinetum. The Luzulo-Quercetum is an association with a typically sub-continental distribution; the two communities with Pinus sylvestris are clearly more continental. The Luzulo-Quercetum oak forest represents a climatic climax and the pine forests are considered edaphic climaxes linked to very dry soils (Leucobryo-Pinetum) or peaty soils (Vaccinio uliginosi-Pinetum). These three associations determine a forest sequence that is typical of sub-continental areas in which Quercus petraea dominates in the climatic climax. In more continental areas, it is gradually replaced by Pinus sylvestris. Thus, the forest sequence in Pays de Bitche represents a remarkable subcontinental link in the transition from Atlantic oak forests to continental pine forests.     

β-oxidation enzymes and the carnitine-dependent oxidation of palmitate and palmitoyl CoA in mitochondria from avocado

Two sites for the β-oxidation of fatty acids in avocado (Persea americana L.) mesocarp exist. One site is the microbody, the other the mitochondrion. It is apparent that the mitochondrial membrane barrier, which remains intact after sucrose density gradient centrifugation, prevents rapid access of acyl CoA substrates to matrix β-oxidation sites. Thus, intact mitochondria showed little β-oxidation enzyme activity. Rupturing of the mitochondrial membrane allowed rapid access of the acyl CoA substrates to matrix sites. Consequently, in ruptured mitochondria, high O₂-oxidation enzyme activities were measured. O₂ uptake studies further distinguished the two organellar sites of β-oxidation. During palmitoyl CoA oxidation, O₂ uptake was reduced by catalase and increased by KCN in the microbodies, whilst mitochondrial O₂ uptake was unaffected by catalase and reduced by KCN. This reflected the differing fates of FADH₂, produced during the first β-oxidation step, in the two organelles. In addition, only the mitochondrial β-oxidation of fatty acids was carnitine-dependent.     

A proposal for the metal geometry in yeast superoxide dismutase based on results from EXAFS spectroscopy

Extended x-ray absorption fine structure (EXAFS) spectra have been recorded at the Cu edge and Zn edge in native yeast superoxide dismutase and at the Cu edge and Cd edge in the yeast superoxide dismutase derivative, where Zn has been substituted with Cd. Two different metal ligand distances in the range 1.9-2.0 A and 2.3-2.4 are determined for the Cu and Zn metals. For Cd in the Zn site two different metal ligand distances about 2.2 A and 2.6 A, respectively, were found. The striking feature is the similarity between the amplitude and radii determined for both the Cu and Zn sites. The increased distances for Cd can be explained by the increased ionic radius of Cd relative to Cu and Zn. Based on these EXAFS results and other relevant knowledge about the metal geometries, we propose that histidine 61 (63) positioned between the Cu and Zn metals are in one subunit bound to Zn and in the other to Cu. This model explains the recently observed difference between the two metal sites in each subunit.     

A study on the renaturation of membrane proteins after solubilization in SDS or following polyacrylamide gel electrophoresis in SDS,with special reference to a phosphatase from acholeplasma laidlawii

It may be easier to renature SDS-denatured hydrophobic proteins than to renature SDS-denatured water-soluble proteins. This paper presents some support for this hypothesis in the form of literature reports and an experiment of our own with an intrinsic membrane protein (a phosphatase from Acholeplasma laidlawii), that could be completely renatured, to judge from the restored activity, which was equal to (or higher than) that of the untreated enzyme. If this hypothesis is correct it might be possible to devise general methods to reverse the SDS denaturation of hydrophobic membrane proteins. This would be a breakthrough in the purification of at least some membrane proteins, because the high-resolving polyacrylamide gel electrophoresis in SDS could then be used to prepare membrane proteins in a native state. The method used for the renaturation of the SDS-denatured, entirely inactive, phosphatase comprised removal of SDS with the aid of conventional dialysis against a buffer containing the neutral, very efficient and non ultraviolet light-absorbing detergent G3707. For renaturation of the enzyme following an SDS-electrophoresis in polyacrylamide the gel was immersed in the same buffer for several hours; by staining for phosphatase the enzyme could easily be localized in the gel in the form of a yellow band, coinciding with a protein zone.     

Sequence variation in CYP51A from the Y strain of Trypanosoma cruzi alters its sensitivity to inhibition

CYP51 (sterol 14α-demethylase) is an efficient target for clinical and agricultural antifungals and an emerging target for treatment of Chagas disease, the infection that is caused by multiple strains of a protozoan pathogen Trypanosoma cruzi. Here, we analyze CYP51A from the Y strain T. cruzi. In this protein, proline 355, a residue highly conserved across the CYP51 family, is replaced with serine. The purified enzyme retains its catalytic activity, yet has been found less susceptible to inhibition. These biochemical data are consistent with cellular experiments, both in insect and human stages of the pathogen. Comparative structural analysis of CYP51 complexes with VNI and two derivatives suggests that broad-spectrum CYP51 inhibitors are likely to be preferable as antichagasic drug candidates.