MORBILLIVIRUS INFECTION IN BOTTLENOSE DOLPHINS: EVIDENCE FOR RECURRENT EPIZOOTICS IN THE WESTERN ATLANTIC AND GULF OF MEXICO

Morbillivirus infection is widespread among odontocetes of the western Atlantic and Gulf of Mexico. Serologic evidence of infection in bottlenose dolphins, Tursiops truncatus , was first detected during an epizootic along the mid-Atlantic coast in 1987. Here, we report recurrent epizootics in the coastal dolphin population since at least the early 1980s based on serological surveys and regional stranding frequencies. The first observed epizootic of this series occurred in the Indian and Banana Rivers in 1982 and was followed by others on the mid-Atlantic coast in 1987–1988 and in the Gulf of Mexico between 1992 and 1994. This temporal pattern of infection is likely facilitated by the population size and its fragmentation into relatively discrete coastal communities. Introduction of morbillivirus into a community with a sufficient number of naive hosts may precipitate an epizootic, depending on the potential for transmission within the group. Propagation of an epizootic along the coast is probably determined by frequency of contact between adjacent communities and seasonal migrations.
Morbillivirus antibodies were also detected in serum from offshore bottlenose dolphins. The sero-prevalence in the latter may be higher than in coastal dolphins because of their close association with enzootically infected pilot whales ( Globicephala spp.). Occasional contact between offshore and coastal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities.     

Projection pattern of sensory neurons in the central nervous system of a homeotic mutation of the moth Manduca sexta

Octopod (Octo) is a mutation of the moth Manduca sexta, which transforms the first abdominal segment (A1) in the anterior direction. Mutant animals are characterized by the appearance of homeotic thoracic-like legs on A1. We exploited this mutation to determine what rules might be used in specifying the fates of sensory neurons located on the body surface of larval Manduca. Mechanical stimulation of homeotic leg sensilla did not cause reflexive movements of the homeotic legs, but elicited responses similar to those observed following stimulation of ventral A1 body wall hairs. Intracellular recordings demonstrated that several of the motoneurons in the A1 ganglion received inputs from the homeotic sensory hairs. The responses of these motoneurons to stimulation of homeotic sensilla resembled their responses to stimulation of ventral body wall sensilla. Cobalt fills revealed that the mutation transformed the segmental projection pattern of only the sensory neurons located on the ventral surface of A1, resulting in a greater number with intersegmental projection patterns typical of sensory neurons found on the thoracic body wall. Many of the sensory neurons on the homeotic legs had intersegmental projection patterns typical of abdominal sensory neurons: an anteriorly directed projection terminating in the third thoracic ganglion (T3). Once this projection reached T3, however, it mimicked the projections of the thoracic leg sensory neurons. These results demonstrate that the same rules are not used in the establishment of the intersegmental and leg-specific projection patterns. Segmental identity influences the intersegmental projection pattern of the sensory neurons of Manduca, whereas the leg-specific projections are consistent with a role for positional information in determining their pattern. © 1995 John Wiley & Sons, Inc.     

武汉东湖水生植被及其恢复途径探讨

１９９２～１９９３年对武汉东湖三个主要湖区（郭郑湖、汤林湖和牛巢湖）水生植被的调查表明,该湖区共有水生植物３２种,优势种为大茨藻、狐尾藻、苦草和菱。金鱼藻呈不断扩大的趋势。植被类型可分为１１个群丛,植被面积约为０．６５ｋｍ￣２,总生物量为１２３６．３９ｔ（湿重）,植被带状分布仅见于汤林湖北部和其他部分湖汊。汤林湖和牛巢湖水生植被正处于自然恢复演替阶段。     

毛喉萜对人胃癌细胞BGC－823中蛋白激酶C及其亚类的影响

以人胃癌细胞ＢＧＣ－８２３为模型,研究了毛喉萜（ｆｏｒｓｋｏｌｉｎ）对胃癌细胞中蛋白激酶Ｃ活性及其亚类基因表达的作用,同时也观察了毛喉萜对癌基因ｃ－ｊｕｎ及抑癌基因ｐ５３表达的影响．结果表明,２×１０~（－５）ｍｏｌ／Ｌ毛喉萜处理ＢＧＣ－８２３细胞７２ｈ,细胞质、膜和细胞核ＰＫＣ活性下降,ＰＫＣ亚类β,γ基因表达被抑制,癌基因ｃ－ｊｕｎ的表达也明显降低,而抑癌基因ｐ５３表达升高,上述变化可能是毛喉萜抑制胃癌细胞增殖等生理效应的重要分子事件。     

Impact of grazing on vegetation dynamics in former ricefields

Abstract. In the Rhône delta, Juncus gerardi and Scirpus maritimus are often the dominant species in abandoned rice fields which are artificially flooded in early spring to improve forage production. Under these conditions they occur either in mixed communities, or form monospecific stands. Monitoring the vegetation dynamics in quadrats located in six abandoned rice fields artificially flooded from November to April confirmed the important role of grazing. In ungrazed plots, communities dominated by Scirpus maritimus mixed with Juncus gerardi developed fast. After 42 months of management Scirpus maritimus had established in nearly all quadrats and continued to expand, whereas Juncus gerardi had started to decline. In grazed plots Juncus gerardi alone dominated and continued to increase in cover up to the 42nd month. Scirpus maritimus established at low densities mainly in quadrats where Juncus gerardi was initially absent. Introduction of seeds of Scirpus maritimus in communities of Juncus gerardi under controlled conditions demonstrated the existence of the phenomenon of preemption. The increase in cover of Juncus gerardi suggests that the preemption of Juncus gerardi over Scirpus maritimus plays a more pronounced role in the field in the presence of grazing.     

Localisation of substance P-like immunoreactivity in the ciliary ganglia of monkey (Macaca fascicularis) and cat: a light- and electron-microscopic study

The present study describes substance P-like immunoreactivity in the ciliary ganglia of monkey (Macaca fascicularis) and cat. About 60% of neurons in the monkey ciliary ganglion and 40% in the cat ciliary ganglion were substance P-like immunoreactive, ranging from faint to moderate staining. Substance P-like immunoreactivity was located in cell bodies, dendritic profiles and axons. In the monkey, substance P-like immunoreactive pericellular arborisations were associated with about 0.5%–3% of the ganglion cells, which were either negatively, faintly or moderately stained. An electron-microscopic study demonstrated the presence of either substance P-like immunoreactive positive or negative axon terminals synapsing or closely associated with positive dendritic profiles in both the monkey and cat ciliary ganglia. The results suggest that substance P plays an important role in the ciliary ganglion, perhaps as a modulator or transmitter.     

Fly pollination of Linum lewish (Linaceae)

This study examines the reproductive biology of Linum lewisii Pursh. (Linaceae), a polyphilic species visited by small bees and generalist flies in montane Colorado. L. lewisii plants growing at different sites experience large temporal and spatial variations in pollinator visits. Their ability to attract both dipteran and hymenopteran pollinators allows pollination under varying conditions as pollinator pool composition changes. Although L. lewisii is self-compatible, hand-pollination studies indicate that insects are required for seed production. The relative effectiveness of fly and bee pollinators is assessed in terms of per-visit pollen deposition. Insect visitation patterns are combined with per-visit effectiveness data to evaluate the relative importance of different pollinator groups. Overall, bees tend to be more effective than flies in depositing pollen. However, in many instances flies appear to be responsible for more pollen deposition due to their higher visitation rates.     

The effect of ferredoxin(BED) overexpression on benzene dioxygenase activity in Pseudomonas putida ML2.

The benzene dioxygenase from Pseudomonas putida ML2 is a multicomponent complex comprising a flavoprotein reductase, a ferredoxin, and a terminal iron-sulfur protein (ISP). The catalytic activity of the isolated complex shows a nonlinear relationship with protein concentration in cell extracts, with the limiting factor for activity in vitro being ferredoxin(BED). The relative levels of the three components were analyzed by using 125I-labelled antibodies, and the functional molar ratio of ISP(BED), ferredoxin(BED), and reductase(BED) was shown to be 1:0.9:0.8, respectively. The concentration of ferredoxin(BED) was confirmed by quantitative electron paramagnetic resonance spectroscopy of the 2Fe-2S centers in ferredoxin(BED) and ISP(BED) of whole cells. These results demonstrate that the ferredoxin(BED) component is a limiting factor in dioxygenase activity in vitro. To determine if it is a limiting factor in vivo, a plasmid (pJRM606) overproducing ferredoxin(BED) was introduced into P. putida ML2. The benzene dioxygenase activity of this strain, measured in cell extracts, was fivefold greater than in the wild type, and the activity was linear with protein concentration in cell extracts above 2 mg/ml. Western blotting (immunoblotting) and electron paramagnetic resonance spectroscopic analysis confirmed an elevated level of ferredoxin(BED) protein and active redox centers in the recombinant strain. However, in these cells, the increased level of ferredoxin(BED) had no effect on the overall rate of benzene oxidation by whole cells. Thus, we conclude that ferredoxin(BED) is not limiting at the high intracellular concentration (0.48 mM) found in cells.