The internet-based fungal pathogen database: a proposed model

ABSTRACT A better understanding of the phenotypic and genetic diversity of significant agricultural pathogens and how their populations change in the field is critical for designing successful, long-term disease management strategies. Although efforts to determine the genetic diversity of plant pathogens have substantially increased in recent years, mainly due to the availability of various molecular tools, complementary efforts to archive and integrate the resulting data have been very limited. As a consequence, it is often difficult to compare the available data from various laboratories because the data have been generated by diverse tools, often preventing any direct comparisons, and are saved in a format that is unsuitable for comparative studies. The establishment of an internet-based database that cross-links the digitized genotypic and phenotypic information of individual pathogens at both the species and population levels may allow us to effectively address these problems by coordinating the generation of data and its subsequent archiving. We discuss the needs, benefits, and potential structure of such a database.     

Comparison of horse mackerel and tilapia surimi gel based on rheological and <Superscript>1</Superscript>H NMR relaxation properties

ABSTRACT:   Horse mackerel and tilapia surimi were subjected to six different heat and pressure treatments in order to compare gelation characteristics of easy- and difficult-setting gels, that is, temperature dependence, by observing rheological properties and microscopic molecular mobility. The stress–relaxation and proton spin–spin relaxation time (¹H T ₂) of water were measured for all treated gels. Horse mackerel gel demonstrated higher elasticity, large distribution of the stress–relaxation process, and smaller water ¹H T ₂ than tilapia in both heat and pressure treatments. The water ¹H T ₂ was steeply increased in the pressure treatment at around 294 MPa for both fishes. In contrast, the ¹H T ₂ rarely changed in the heat treatment in spite of the considerable change in rheological properties. From the experimental results, it is considered that the gelation of horse mackerel (easy setting) surimi is induced by highly unfolding and re-aggregation of protein, which contributes to the formation of a strong network structure compared with tilapia in both heat and pressure treatments, and that pressure treatments hardly improve the gel strength of tilapia (difficult setting) surimi. The water ¹H T ₂ measurement was used effectively in order to study gelation characteristics of easy- and difficult-setting fish through observing its molecular dynamics.     

The potential of mixed culture of genetically improved farmed tilapia (Oreochromis niloticus) and freshwater giant prawn (Macrobrachium rosenbergii) in periphyton-based systems

The production performance of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) in periphyton‐based systems were studied in farmers' ponds at Mymensingh, Bangladesh. Fifteen ponds (200–300 m² area and 1.0–1.5 m in depth) were used to compare five stocking ratios in triplicate: 100% GIFT, 75% GIFT plus 25% prawn, 50% GIFT plus 50% prawn, 25% GIFT plus 75% prawn and 100% prawn. Ponds were stocked at a total density of 20 000 GIFT and/or prawn ha^?1. Bamboo poles (mean diameter 6.2 cm and 5.5 pole m^?2) were posted in pond bottoms vertically as periphyton substrate. Periphyton biomass in terms of dry matter (DM), ash‐free DM and chlorophyll a were significantly higher in ponds stocked with prawn alone than in ponds with different combinations of GIFT and prawn. Survival of GIFT was significantly lower in ponds stocked with 100% GIFT (monoculture) whereas, that of prawn was significantly higher in its monoculture ponds indicating detrimental effects of GIFT on prawn's survival. Individual weight gains for both species were significantly higher in polyculture than in monoculture. The highest total fish and prawn yield (1623 kg GIFT and 30 kg prawn ha^?1) over 125–140 days culture period was recorded in ponds with 75% GIFT and 25% prawn followed by 100% GIFT alone (1549 kg ha^?1), 50% GIFT plus 50% prawn (1114 kg GIFT and 68 kg prawn ha^?1), 25% GIFT plus 75% prawn (574 kg GIFT and 129 kg prawn ha^?1) and 100% prawn alone (157 kg ha^?1). This combination also gave the highest economic return. Therefore, a stocking ratio of 75% GIFT plus 25% prawn at a total density of 20 000 ha^?1 appeared to be the best stocking ratio in terms of fish production as well as economics for a periphyton‐based polyculture system.     

Congenital Defects in Indigenous Cattle of Bangladesh

Tropical Animal Health and Production -     

Anestrus and “Repeat Breeding” Problems of Indigenous Cattle in Bangladesh

Tropical Animal Health and Production -     

二倍体与四倍体刺槐组培苗形态和生理性状比较

为了比较二倍体与四倍体刺槐组培苗不同无性系之间的差异,本研究分别测定二倍体刺槐组培苗和人工诱导四倍体刺槐组培苗的形态及生理指标,并进行相关分析。结果表明,多数四倍体刺槐无性系的长势、抗逆性优于二倍体;二倍体与四倍体刺槐不同无性系以及不同形态、生理指标之间存在丰富的变异,其中四倍体刺槐的变异更为丰富;各测定指标之间存在较为复杂的相关关系,在选择育种时,需综合考虑。根据试验结果,结合育种目标,可选育出优良四倍体刺槐无性系,丰富刺槐种质资源,增加遗传多样性。本研究为刺槐倍性育种工作提供了理论依据和科学参考。     

Effects of dwarfing genes on yield and yield components under irrigated and rainfed conditions in wheat (Triticum aestivum L.)

Summary Near-isogenic tall (no dwarfing gene), semidwarf (Rht1 or Rht2) and dwarf (Rht1 + Rht2 or Rht3) spring wheat lines were evaluated for yield and yield components under irrigated and rainfed conditions. Under irrigated conditions, the dwarf and the semidwarf lines exhibited a significant yield advantage over the tall lines. Under rainfed conditions, the semidwarf lines outyielded the tall as well as the dwarf lines. Percent yield reduction in response to drought stress was highest with the dwarfs and lowest with the tall lines. Dry matter production of the tall lines and that of the semidwarf lines did not differ significantly and both produced significantly more dry matter than the dwarf lines under irrigated as well as rainfed conditions. Plant height and kernel weight decreased with increasing degree of dwarfness while number of kernels per spikelet, harvest index and days to heading increased under both moisture regimes. The dwarfing genes did not have any significant influence on number of tillers/m² and spikelets per spike in either moisture regime.     

Quantitative and qualitative studies on bacterial flora of hybrid tilapia (Oreochromis niloticus × O. aureus) cultured in earthen ponds in Saudi Arabia

The bacterial flora of the rearing pond water and sediment as well as the gills and intestine of healthy hybrid tilapia cultured in Saudi Arabia was estimated quantitatively and qualitatively, the isolates being identified at genus or species level. Total viable counts of bacteria (measured as colony‐forming units, cfu) were in the range 5.6 ± 0.8 × 10³ to 2.4 ± 1.2 × 10⁴ cfu mL^?1 in pond water; 9.3 ± 1.1 × 10⁶ to 1.9 ± 1.5 × 10⁸ cfu g^?1 in sediment; 7.1 ± 0.7 × 10⁵ to 8.7 ± 1.1 × 10⁶ cfu g^?1 in the gills of tilapia; and 3.4 ± 1.8 × 10⁶ to 5.8 ± 0.4 × 10⁷ cfu g^?1 in the intestine of tilapia. In total, 15 bacterial genera and 18 species were identified. Pond water and sediment bacteria reflected the bacterial composition in the gills and intestine of tilapia. In contrast to gill bacteria, more diversification was observed in intestinal bacteria. Corynebacterium urealyticum, Shewanella putrefaciens and Aeromonas hydrophila predominated in all samples. In pond water, C. urealyticurn, S. putrefaciens, A. hydrophila, Flavobacterium sp. and Pseudomonas sp. were the most predominant bacterial species (prevalence > 10%), whereas A. hydrophila, C. urealyticum, S. putrefaciens and Escherichia coli were predominant in pond sediment, and C. urealyticum, S. putrefaciens and A. hydrophila were predominant in both the gills and intestine of tilapia.