Introductions, spread and colonization of new localities by fish helminth and crustacean parasites in the British Isles: a perspective and appraisal

Most parasites are disseminated by movements of infected hosts. The increasing extent and rapidity of anthropochore fish movements are causing increased concern related to awareness of their potential and known capacity for disseminating parasites. This paper puts these data in perspective by examining examples of actual and potential translocations of fish helminthes and crustaceans by anthropochore movements offish into and throughout the British Isles, and by distinguishing the processes of dissemination and invasiveness from those of colonization and establishment. An investigation of the British fish and helminth parasite fauna suggests that: (1) the range of many species is not well known, many are local in distribution and appearances beyond the range may reflect detection and patchiness, not translocation; (2) taxonomic problems in many groups hinder detection and determination of range; (3) most parasites possess the attributes of good colonizers so the natural expansion and contraction of ranges are often not noticed or recognized as such and the importance of parasite introductions by natural movements of fish or avian hosts is generally underestimated; (4) invasions are far commoner than colonizations, since conditions for establishment may be very restricted and transmission windows very narrow in time and space; (5) successful colonizations and translocations tend to be documented and attract attention whereas invasions resulting in failed colonizations are seldom observed and more seldom documented, thus biasing our perception. Given the extensive history of fish introductions to, and translocations within, the British Isles it is surprising how few fish helminths and crustaceans have invaded the country successfully (16 species: 11·4%) and how many still show restricted distributions. The majority (68·7%) of introduced helminths are associated with fish having ornamental varieties. Barriers of colonization are more effective than those to invasion and it is clear that most translocations and invasions fail. It is right to be concerned about the dangers, but it is also important to put anthropochore factors in perspective.     

Patterns in the composition and richness of helminth communities in brown trout, Salmo trutta, in a group of reservoirs

Helminth community composition and richness were studied in brown trout, Salmo trutta , in 10 reservoirs of broadly similar age and characteristics situated close to each other in a well-defined region of south-west England. Communities were compared using cluster and ordination analyses, and possible correlations between helminth richness and a number of environmental variables were investigated. The hypothesis that the helminth communities should show high degrees of similarity and that large differences between reservoirs and a high degree of clustering would be unrecognizable was refuted. Levels of community similarity were low and comparable to those determined for helminths in salmonids in natural lakes. Trout in some reservoirs exhibited very distinctive helminth faunas and clustering of reservoirs was apparent. No single factor, including reservoir size and presence of piscivorous birds, had a predominant influence on community richness or composition but rather a multiplicity of local factors was believed to influence these parameters. The results indicate that local factors promoting distinctiveness have a greater influence on the composition and richness of fish helminth communities in lakes and reservoirs than do regional factors promoting similarity.     

Observations of the biology and parasites of postsmolt Atlantic salmon, Salmo salar, from the Norwegian sea

The main food items of postsmolt Atlantic salmon caught in the Norwegian sea during summer 1991 were Parathemisto spp. and herring ( Chipca harengus ). The most prevalent parasite species were Chloromyxion sp., Apatemon sp., H. adunction, A simplex and I. salmonis .     

Caprine blood groups. 1. The B system

Twelve of 24 monospecific caprine reagents produced by absorption of alloimmune antisera identified a complex blood group system of goats which was designated B, based on the results of a small comparison test with ovine reagents. The frequencies of the 12 B factors differed significantly among the Australian Angora, Texan Angora, Cashmere, and Dairy goat breeds. Three of the antigens detected by the reagents were shown to be related as linear subtypes, designated Ba₁, Ba₂, and Ba₃, and inherited as alleles. The segregations of B factors in 80 sire groups involving 1086 offspring demonstrated that groups of B factors (phenogroups) segregated as products of allelic genes. This work was supported by a grant from the Australian Stud Book, Alison Road, Randwick, New South Wales 2031, Australia.     

Effects of body and head positions on bilateral difference in tympanic temperatures

We have examined the nonparallel changes in tampanic membrane temperatures (T _ty) from the two ears in response to various changes in body and head positions. Upon assuming a lateral recumbent position, the T _ty on the lower side increased while that on the upper side decreased. Pressure application over a wide area of the lateral chest only caused inconsistent and obscure asymmetric changes in T _ty. A lateral flexion of the head with the subject sitting upright and a rotation of the head to the side in a supine position induced an increase in the T _ty on the lower side compared to that on the upper side. The temperature and blood flow of the forehead often decreased on the lower side and increased on the upper side, although such responses were not always concomitant with the asymmetric changes in T _ty. A dorsal flexion of the head with the subject in a reclining position caused a slight increase in the T _ty, whereas raising the head upright induced a slight decrease in them. Two additional experiments were carried out with single photon emission computed tomography using ^99mTc-hexamethylpropyleneamine oxime as tracer, and a slight, relative decrease in counts was noted in the right hemisphere during rotation of the head to the right. These results would strongly suggest that unilateral increases and decreases in T _ty could have been caused by one-sided decreases and increases, respectively, in blood flow to the brain and/or the tympanic membrane, induced by a vasomotor reflex involving vestibular stimulation.     

Severe hypoxia decreases oxygen uptake relative to intensity during submaximal graded exercise

The effect of severe acute hypoxia (fractional concentration of inspired oxygen equalled 0.104) was studied in nine male subjects performing an incremental exercise test. For power outputs over 125 W, all the subjects in a state of hypoxia showed a decrease in oxygen consumption ( O₂) relative to exercise intensity compared with normoxia (P < 0.05). This would suggest an increased anaerobic metabolism as an energy source during hypoxic exercise. During submaximal exercise, for a given O₂, higher blood lactate concentrations were found in hypoxia than in normoxia (P < 0.05). In consequence, the onset of blood lactate accumulation (OBLA) was shifted to a lower O₂ ( O₂ 1.77 l·min^–1 in hypoxia vs 3.10 l·min^–1 in normoxia). Lactate concentration increases relative to minute ventilation ( _E) responses were significantly higher during hypoxia than in normoxia (P < 0.05). At OBLA, _E during hypoxia was 25% lower than in the normoxic test. This study would suggest that in hypoxia subjects are able to use an increased anaerobic metabolism to maintain exercise performance.     

Localization of neuropeptide Y and atrial natriuretic peptide in the endothelial cells of human umibilical blood vessels

The localization of neuropeptide Y (NPY) and atrial natriuretic peptide (ANP) in the endothelial cells of human umbilical blood vessels was studied using the pre-embedding peroxidase-antiperoxidase (PAP) technique for electron microscopy and avidin-biotin-complex (ABC) immunostaining for endothelial cells cultured from umbilical vein. Subpopulations of NPY- and ANP-immunoreactive endothelial cells were present in term umbilical vein and artery. The umbilical vein contained more positive cells than the artery. The percentage of NPY- and ANP-immunoreactive umbilical vein cells in culture was 32% and 44%, respectively, out of a total of 3013 cells examined. The possibility that these potent vasoactive substances located in the endothelial cells of the non-innervated umbilical vessels are involved in the local regulation of blood flow is discussed.     

Source of an egg kairomone for Trissolcus basalis, a parasitoid of Nezara viridula

Abstract. The eggs of the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae), are successfully attacked by Trissolcus basalis (Woll.) (Hymenoptera: Scelionidae) and are recognized as hosts by a secretion applied to the egg chorion. This secretion is produced by the follicular cells in the proximal region of the ovariole of the female pentatomid and functions as an adhesive for attaching the eggs to the oviposition substrate. The adhesive and kairomone activity could be partially removed with water. This water extract elicited host recognition behaviour in T. basalis when applied to glass beads which stuck together as the extract dried. The adhesive and kairomonal activity was removed completely with acetone since acetone-washed host eggs were not recognized by T. basalis. Application of the acetone extract to glass beads stimulated ovipositional probes by T. basalis. The adhesive appeared to be composed of a mucopolysaccharide–protein complex.     

Cytotoxic cell function and phenotypic analysis of peripheral blood mononuclear cells in cancer patients treated with low-dose interleukin-2 and mitomycin C

We previously found that the ability of peripheral blood mononuclear cells (PBM) of cancer patients to generate lymphokine-activated killer (LAK) cells became remarkably augmented after mitomycin C administration. On the basis of the clinical finding, we designed a treatment regimen comprised of 12 mg/m² mitomycin C i. v. on day 1 and 700 U/m² recombinant interleukin-2 (IL-2) i.v. every 12 h from day 4 through day 8. Of 25 patients with advanced carcinoma, 9 had a partial response and 3 had a minor response. Cytotoxic cell function, including natural killer activity, lymphokine-activated killer (LAK) activity, and the ability to generate LAK cells, and lymphocyte subsets in PBM was measured 1 day before and after either the first or second course of this therapy. The relationship between these parameters and the clinical antitumor response to this treatment was examined. Although the cytotoxic activities were significantly augmented after either the first or second treatment course, no positive correlation was observed between the changes in these cytotoxic activities and the clinical response to this therapy, when patients who either showed a partial response or whose disease remission was partial or minor were defined as responders. Further, phenotypic analysis showed a significant increase in CD2⁺, CD3⁺ CD4⁺ and CD4⁺Leu8^– cells after the firs course, and CD25⁺ cells after either the first or second course of this treatment. The precentages of CD2⁺ and CD25⁺ cells were significantly elevated only in responders but not in nonresponders, suggesting the increase in these subsets was related to clinical response.     

激光诱导家蚕孤雌生殖的研究——Ⅴ.突变体蛹血酯酶同工酶的分析

试验用聚丙烯酰胺凝胶电泳,对激光诱导家蚕孤雌生殖新育成的突变体Lamp_1和Lamp_2蛹血EST同工酶进行了分析。结果说明这两个突变体是新突变体,客观存在的酶谱特征不同于未用激光照射的CK蚕种。