Variations in the migratory history of the tropical catadromous eels Anguilla bicolor bicolor and A. bicolor pacifica in south-east Asian waters

Fish movements between aquatic habitats of different salinity ranges (fresh, estuarine, marine) by the tropical catadromous eels Anguilla bicolor bicolor and A. bicolor pacifica were examined by analysing the otolith strontium and calcium concentrations of yellow (immature) and silver (mature) stage eels collected in south-east Asian (Indonesia, Malaysia and Vietnam) waters. The ratios suggest that all migratory-type eels, including freshwater, brackish water and marine residents, pass the river mouth. However, the habitat preference was different among the sites (countries). In Indonesia and Vietnam, most A. bicolor bicolor and A. bicolor pacifica were either marine or brackish water residents in this study. Alternatively, most A. bicolor bicolor were freshwater residents in Malaysia; such a typical catadromous migration pattern in these eels has not been found in previous studies. The wide range of otolith Sr:Ca in both subspecies indicates that the habitat use of these tropical eels was opportunistic among fresh, brackish and marine waters during their growth phases following recruitment to coastal areas. The geographical variability of migratory histories suggests that habitat use might be determined by the inter and intraspecific competition and environmental conditions at each site.     

The leucocyte enzyme cytochemistry of the Indian eel, Anguilla bicolor bicolor McClelland

Activity of peroxidase, alkaline phosphatase, acid phosphatase, α-naphthyl acetate esterase and naphthol-AS-D chloroacetate esterase in the leucocytes of the Indian eel, Anguilla bicolor bicolor McClelland, was studied. But for some minor differences, the enzyme pattern of the leucocytes, especially neutrophil peroxidase, of the Indian eel closely resembled that of the New Zealand eels, suggesting that the Indian eel is phylogenetically more closely allied to the New Zealand eels than to the European eel.     

Relationship between roving behaviour and the diet and client composition of the cleaner fish Labroides bicolor

Diet analyses and observations of cleaning behaviour of two cleaner fishes revealed that Labroides bicolor fed more on client mucus, but Labroides dimidiatus fed more on ectoparasites, and that L. bicolor interacted with fewer species (36 species) compared with L. dimidiatus (44 species). The client species which contributed most to the dissimilarity between cleaner species were the dusky farmerfish Stegastes nigricans and bicolor chromis Chromis margaritifer damselfishes, which L. dimidiatus interacted with more often than L. bicolor, and the striated Ctenochaetus striatus and brown Acanthurus nigrofuscus surgeonfishes, which L. bicolor interacted with more; L. bicolor interacted with all parrotfishes (Scaridae) more. These results confirm the importance of repeated interactions and partner choice in determining the nature of interactions in mutualisms.     

Morphological and allozyme studies of small terrestrial snails (Opeas sp., Subulina sp. and Huttonella bicolor) collected from Peninsular Malaysia

Shell morphological characters and allozyme electrophoresis were used to study the relationships among six geographical populations of land snails collected from Peninsular Malaysia. Allozyme electrophoresis was used to study the genetic variations to complement the morphological features studied that included shell lengths, numbers of whorls and shell colour. Ten loci coding for six enzymes (MDH, LAP, ALP, PGM, G6PDH and EST) could be reliably scored in samples from the six populations studied. The dendrogram showed two major clusters with one cluster comprising Subulinidae populations from Perak, Selangor, Johor, Terengganu and Pahang while the other cluster included only the Streptaxidae Huttonella bicolor (red) population. The Subulinidae populations were grouped into two subclusters: one subcluster included the Subulina sp. populations from Perak, Selangor an Johor while the other subcluster included the Opeas sp. populations from Terengganu and Pahang. Morphological features can identify the different families and therefore they can complement the allozyme genetic studies on the land snail populations. Like other reports in the literature, our results also underline the importance of a genetic approach in conjunction with a morphological approach, for discriminating land snail species. The present results suggest that small land snails, which were similar in colour but different in sizes, were not of the same family/genus.     

Age and growth of Anguilla bicolor bicolor leptocephali in the eastern Indian Ocean

A sampling survey for leptocephali was conducted in the eastern Indian Ocean to the west of Sumatra from 5 to 20 June 2003 in an overlapping area with the historical survey in September to November 1929 during the Danish Round the World Expedition. The age and larval growth rate of 34 Anguilla bicolor bicolor collected in 2003 were estimated using their otolith microstructure to obtain new information about the early life history of this sub-species. The total lengths and ages of these leptocephali were 44·1–55·5 mm and 114–158 days, respectively. Their hatching dates ranged from 3 January to 20 February 2003. Combining these age data and the estimated age of leptocephali collected by others in the same area, this sub-species was estimated to have a wide range of spawning periods. Individual growth rates of the leptocephali in 2003 ranged from 0·32 to 0·39 mm day⁻¹ with a mean ± s . d . of 0·35 ± 0·02 mm day⁻¹. These values were lower than the growth rates of leptocephali of other tropical eels such as Anguilla celebesensis or Anguilla borneensis , suggesting that A. b. bicolor from the eastern Indian Ocean have a longer leptocephalus period of oceanic migration.     

Population dynamics of mangrove Avicennia bicolor on the Pacific coast of Costa Rica

Deterministic and stochastic class structured population models were used to simulate the life cycle of Avicennia bicolor of the Pacific coast of Costa Rica. The models were based on an extensive data set collected during a 6 year period in a 0.52 ha plot of monospecific A. bicolor. This data set included density, growth, mortality and transition rates of seedlings, saplings and trees of eight different diameter classes, as well as propagule production for the reproductive tree classes. Model simulations carried out over a 100 year period indicated a stable size class structure of the forest. Sensitivity analysis showed a significantly greater sensitivity of the model population to simulated changes in the mortality of seedlings, in comparison with the mortality of saplings and trees. An increase of 1% in the mortality of seedlings, for example, was sufficient to cause significant changes in the density of individual size classes. In contrast, neither a 10% increase in the mortality of saplings and trees nor a 20% decrease in the propagule production of fecund trees significantly affected the overall forest structure.     

The behaviour of laying workers and the morphology and viability of their eggs in Melipona bicolor bicolor

Abstract. As in many other stingless bees, Melipona bicolor bicolor Lepeletier (Apidae: Meliponinae) workers lay two morphologically distinct types of eggs: slender ones that have a typical patterned chorion, and larger ones that lack this pattern. In this paper we report on the relation between egg morphology and the behaviour of the workers that lay such eggs. In most cases, the laying of each of these egg types is accompanied by a unique sequence of behaviours. After a worker has laid the unpatterned type of egg, she generally leaves the cell, giving the queen the possibility of eating this egg. In the case of the patterned egg type, the worker usually closes the cell immediately after her egg laying. When worker egg laying occurs right after a series of regurgitations, it stops the queen from ovipositing. When, instead, a worker lays an egg after queen oviposition, the cell contains two eggs. This study also revealed cases in which workers laid slender, patterned eggs without closing the cell, and other cases where workers laid large, spherical, unpatterned eggs and instantly closed the cell. Experiments in which worker eggs, destined to be eaten by the queen, were protected by covering the cell artificially with a piece of wax showed that some of these eggs developed into larvae, although they were occasionally relatively small. The occurrence of a range of combinations of egg-laying behaviours and egg morphologies in M. b. bicolor workers is discussed from the perspective of worker egg laying in other stingless bees.     

Advanced sexual maturation before marine migration of Anguilla bicolor bicolor and Anguilla marmorata at Réunion Island

Maturing sub-adults of two species of anguillid eels (a female Anguilla bicolor bicolor and a male Anguilla marmorata ) were collected for the first time at Réunion Island, western Indian Ocean. Both were silver eels, i.e. maturing eels at the onset of their spawning migration, and characterized by advanced sexual maturation that has been only observed in Anguilla dieffenbachii from New Zealand.     

高粱遗传转化研究进展

高粱（Sorghum bicolor）是一种重要的多用途作物, 其遗传转化研究对于高粱的分子育种和分子遗传学基础研究都具有重要意义。该文对高粱遗传转化的方法、标记基因、遗传转化的启动子和受体系统进行了综述, 并提出了今后高粱遗传转化应当集中研究的问题。     

Monitoring the persistence of Laccaria bicolor as an ectomycorrhizal symbiont of nursery-grown Douglas fir by PCR of the rDNA intergenic spacer

The large-scale inoculation of selected beneficial ectomycorrhizal fungi in forest nurseries has generated renewed interest in the ecology of these symbiotic fungi. However, information on the dissemination and persistence of introduced symbionts is scarce due to the limitation of the current identification methods. To identify ectomycorrhizal fungi on single root tips, we investigated the polymorphism of the PCR-amplified ribosomal DNA intergenic spacer (IGS) from a wide range of ectomycorrhizal fungi. To investigate the reliability of this molecular approach in large-scale surveys, the dissemination and persistence on Douglas fir seedlings of the introduced Laccaria bicolor S238N were assessed in a forest nursery in the Massif Central (France). Several hundred ectomycorrhizas and fruiting bodies were sampled from plots where control and L. bicolor inoculated-Douglas fir seedlings were grown for 1.5 years. PCR typing of mycorrhizas indicated that trees inoculated with L. bicolor S238N remained exclusively colonized by that isolate (or sexually derived isolates) for the entire test period. In contrast, control seedlings were infected by indigenous isolates of Laccaria laccata and Thelephora terrestris. The molecular evidence for the persistence of the introduced mycobiont despite the competition from indigenous isolates of the same species provides further illustration of the potential of exotic species for large-scale microbial application.     

二色补血草的耐盐性研究

通过NaCl胁迫发芽试验、盆栽浇灌NaCl盐水试验、不同含盐量土壤的种植试验,研究二色补血草（Limoniumbicolor）3个时期的耐盐能力。结果表明：高浓度NaCl对二色补血草种子的萌发有明显的抑制作用,种子的发芽率与盐浓度之间呈显著的负相关,种子萌发时盐胁迫的适宜值、临界值、极限值分别是0.49%、1.30%、2.11%;盆栽试验结果表明,二色补血草在2.0%以下的NaCl盐水胁迫下没有表现明显的盐害症状,只表现高浓度NaCl胁迫下,生长量低于低浓度处理的,当处理浓度达到2.4%时,多数植株濒临死亡;不同含盐量土壤的种植试验结果表明,在自然条件下,二色补血草成株耐盐临界值为1.7%～1.8%。试验结果说明二色补血草具有较强的耐盐能力,适合在滩涂盐碱地推广种植。     

Genetic recombination in Sorghum bicolor x S. macrospermum interspecific hybrids

Sorghum has been improved by public and private breeding programs utilizing germplasm mostly from within the species Sorghum bicolor. Until recently, cross-incompatibilities have prevented hybridization of S. bicolor with most other species within the genus Sorghum. Utilizing germplasm homozygous for the iap allele, hybrids were readily produced between S. bicolor (2n = 20; AAB1B1) and S. macrospermum (2n = 40; WWXXYYZZ). These hybrids were intermediate to the parents in chromosome number (2n = 30) and overall morphology. Meiosis in both parents was regular; S. bicolor had 10 bivalents per pollen mother cell (PMC) and S. macrospermum had an average of 19.96 bivalents per PMC. Six hybrids were studied cytologically and meiosis was irregular, with the chromosomes associating primarily as univalents and bivalents. There was an average of 3.54 bivalents per PMC, with a range of 0-8 bivalents, most of which were rods (98%). Using FISH (fluorescent in situ hybridization), moderate levels (2.6 II per PMC) of allosyndetic recombination were observed. Genomic relationships were sufficient to assign S. macrospermum the genomic formula AAB1B1YYZZ (Y and Z remain unknown). Allosyndetic recombination in the interspecific hybrids indicates that introgression through genetic recombination should be possible if viable backcrosses can be recovered.     

Chorismate mutase isoenzymes from Sorghum bicolor: immunological characterization

Highly purified fractions of chorismate mutase 1 and 2 from etiolated seedlings of Sorghum bicolor were used as the antigen for antibody production in BALB/c mice. Tests for antigen-antibody complex formation were made by immunodiffusion, immunoprecipitation, and enzyme-linked immunosorbent assay (ELISA). These tests indicated the presence of specific antibodies for each isoenzyme in their antisera. However, in the same tests, no cross-reaction was found between chorismate mutase 1 and 2 and their antisera. This indicates no immunological similarity between the two isoenzymes of chorismate mutase from sorghum.     

Transformation of the mycorrhizal fungus Laccaria bicolor using Agrobacterium tumefaciens

Most boreal and temperate forest trees form a mutualistic symbiosis with soil borne fungi called ectomycorrhiza (ECM). In this association both partners benefit due to nutrient exchange at the symbiotic interface. Laccaria bicolor is the first mycorrhizal fungus with its genome sequenced thus making possible for the first time to analyze genome scale gene expression profiles of a mutualistic fungus. However, in order to be able to take full advantage of the genome sequence, reverse genetic tools are needed. Among them a high throughput transformation system is crucial. Herein we present a detailed protocol for genetic transformation of L. bicolor by means of Agrobacterium tumefaciens with emphasis on critical steps affecting the success and efficiency of the approach.     

两色绿刺蛾幼虫空间分布型

应用聚集度指标法、回归分析法、零频率方法对两色绿刺蛾幼虫在毛竹林间的分布型进行测定。结果表明,两色绿刺蛾幼虫在竹林中呈聚集分布,分布的基本成分为个体群。用零频率方法分析得,两色绿刺蛾幼虫种群类型为聚集度零频率制约型,并确定了林间调查的理论抽样数和简单序贯抽样分析表。     

二色补血草叶片泌盐结构的扫描电镜观察

对二色补血草盐泉结构进行比较研究,发现二色补血草叶下表皮具有花型盐腺,这些盐腺是由基细胞和帽细胞构成,植物体靠盐腺的泌盐孔和基细胞破碎释盐,表明二色补血草具有演化较高级的双重泌盐结构,是二色补血草能在盐碱地生长而不受盐害的主要原因。     

Medical virology in Malaysia

Virology is a branch of biological science dealing with the study of viruses, and medical virology focuses on the study and control of diseases due to viruses that is of medical importance. The development of medical virology in Malaysia has its beginning in the Institute for Medical Research (IMR), following the establishment of the Division of Medical Zoology and Virus Research in the institute on 23 March 1953. The second institution in the country to establish diagnostic and research work in medical virology was Department of Medical Microbiology, Faculty of Medicine, University Malaya. This was followed by University Kebangsaan Malaysia, University Sains Malaysia and University of Sarawak Malaysia. The National Public Health Laboratory (NPHL) is the latest institution to establish a laboratory in 2003 for virus isolation and services to support country surveillance and outbreak investigation of infectious diseases due to viruses. In the field of medical virology, Malaysia contributed substantially in the areas of virus diagnostic services, development and research ranging from survey and documentation on the existence and prevalence of viruses causing diseases in Malaysia, clinical presentation and epidemiological features of virus diseases, evaluation of new diagnostic tests to pathogenesis of viral diseases. Malaysia contributed to the discoveries of at least 12 new viruses in the world. ASEAN plus Three (China, Japan, Republic of Korea) Emerging Infectious Programme was established to overcome the challenges and impact of emerging and re-emerging infectious diseases in this region. Malaysia as the co-ordinator of the laboratory component of the programme, contributed to strengthen the regional laboratory capability, capacity, laboratory-based surveillance and networking. The future of medical virology in Malaysia in terms of integration of diagnostic, reference and research to support the country's need will be enhanced and strengthened with the on-going development of the National Centre for Disease Control and Prevention (CDC Malaysia) which also incorporates a futuristic Special Diagnostic and Reference Laboratory.