Correlation of rotifer associations in a chain of lakes fed by reclaimed sewage

The quantitative composition of the rotifer fauna of seven interconnected lakes located in southern California was studied in a preliminary investigation. The lakes are fed by reclaimed sewage, and the water quality increases rapidly from the first lake, barely able to support life, to a series of lovely lakes stocked with fish and utilized for recreation. The Shannon index of rotifer population diversity showed an appropriate increase. Up to 24 – 28 different rotifer taxa in each lake provided a rich community dominated by Brachionids, Keratella and Trichocerca. The diversity and quantity of the rotifer association then declined again in the last lake. Comparison of the lakes using the Bray and Curtis index of similarity and cluster analysis supported the picture of a lake-chain evolution, a biotic development showing a maximum curve.     

Histofluorescent labelling of catecholaminergic structures in rotifers (Aschelminthes)

Summary 1. Catecholaminergic structures in the male Brachionus plicatilis were investigated, using aqueous dansylpropranolol as fluorescent label of neurotransmitter receptors. 2. All major organs of the male are innervated by catecholaminergic systems, that may also be involved in the regulation of copulatory behavior. 3. Cryostat-sectioned preparations of the female B. plicatilis were also investigated. They provided additional information to findings on whole animals reported in our previous paper (Keshmirian and Nogrady 1987a).     

An outbreak of adenovirus type 7 infection in children in Montreal

Thirteen infants and children with adenovirus type 7 infection proved by virus isolation are described. High fever, cough and dyspnea were the most frequent findings; in infants under 1 year of age wheezing was common. Four patients required artificial ventilation. Lobar collapse, consolidation and hyperinflation were frequent radiologic findings. None of the symptoms responded to antibiotic therapy or bronchodilator drugs. Three patients died (mortality rate of 23%). Pathologic findings were compatible with adenovirus type 7 pneumonia, and were characterized by a necrotizing bronchitis and bronchiolitis, patchy alveolar fibrinopurulent exudate and hyaline membrane formation. Some intra-alveolar epithelial cells showed strikingly abnormal nuclei and rare typical halo-outlined intranuclear inclusions were seen. Only one of eight survivors had evidence of significant chronic chest disease.     

Some new and rare warmwater rotifers

Two new rotifer species, Lecane (Monostyla) aliger n.sp. and Proales pugio n.sp. are described from the Bahama Islands, Florida and California, and their autecology outlined. Some other rare rotifers are discussed which also prefer subtropical conditions. They are: Epiphanes clavulata, Epiphanes brachionus spinosus, Lecane crepida and Proalides tentaculatus tentaculatus. The existence of subtropical rotifer associations is discussed and supported by ecological data.     

Succession of planktonic rotifer populations in some lakes of the Eastern Rift Valley,Kenya

The quantitative succession of the spring and summer rotifer plankton and its biomass in six lakes of the Eastern Rift Valley of Kenya is discussed. The lakes can be divided into two groups: the low conductivity slightly alkaline lakes Naivasha, Oloidien and the Winam Gulf of Lake Victoria; and the high conductivity, highly alkaline-saline lakes Nakuru, Elmenteita and Bogoria. The former three show a qualitatively rich, typical warmwater rotifer association dominated by Brachionids and Filinia. The saline soda lakes are dominated by several populations of Brachionus dimidiatus, which can reach enormous numbers. The taxonomy and biometry of this species was subjected to statistical analysis. Some interesting and rare species are described: Anuraeopsis coelata, Lepadella triptera f. deconincki, Trichocerca gracilis and T. mus.The chemical limnology of the lakes is discussed and compared with other soda lakes in Central Africa, Europe and North America.     

Canadian rotifers II. Parc Mont Tremblant,Quebec

Nine lakes in Mont Tremblant Provincial Park were investigated during summer and fall. Data on lake morphometry and water chemistry are tabulated. Most lakes were oligotrophic, some were dystrophic bog lakes. They contain a rich rotifer fauna and some very rare species, which are described in detail.     

Rotifers from five high arctic ponds (Cape Herschel,Ellesmere Island,N.W.T.)

Five small ponds on Cape Herschel, Ellesmere Island, N.W.T. (latitude 78° 37 N; 74° 42 W) were investigated, and their rotifer fauna discussed. Although the number of individuals is very low, the rotifer assemblage is remarkably rich (33 species), especially considering the harsh environmental conditions, and the short ice-free period of only six weeks. The shallow ponds are all alkaline, and the rotifer species are either cosmopolitan, or very rare. Proales kostei n. sp. is described.on leave from Concordia University, Montreal, Quebecon leave from Concordia University, Montreal, Quebec     

Histofluorescent labelling of catecholaminergic structures in rotifers (Aschelminthes) in whole animals

1. Catecholaminergic neuronal structures were investigated in the rotifers Brachionus plicatilis, Asplanchna priodonta and Asplanchna herricki, using three different aqueous histofluorescent methods. 2. The adrenergic receptors were labelled using the dansyl analog of propranolol, a beta-adrenergic blocker. Catecholamine neurotransmitters were visualized by derivatizing with glyoxylic acid and formaldehyde respectively. 3. Although all three methods lead to similar results, dansyl-propranolol gave the most rapid and strong fluorescence. 4. The results reveal a complex and highly developed catecholaminergic neuronal system in all adult organs and sensory structures. While developed embryos in the egg show strong fluorescence, immature eggs do not.     

Histofluorescent labelling of catecholaminergic structures in rotifers (Aschelminthes). II. Males of Brachionus plicatilis and structures from sectioned females

1. Catecholaminergic structures in the male Brachionus plicatilis were investigated, using aqueous dansylpropranolol as fluorescent label of neurotransmitter receptors. 2. All major organs of the male are innervated by catecholaminergic systems, that may also be involved in the regulation of copulatory behavior. 3. Cryostat-sectioned preparations of the female B. plicatilis were also investigated. They provided additional information to findings on whole animals reported in our previous paper (Keshmirian and Nogrady 1987 a).     

Neuropharmacology of rotifer feeding,oviposition, and anesthesia

Effect of acetylcholine and anticholinergic drugs on feeding, oviposition, and anesthesia in rotifers was investigated. Neurotransmitter as well as antagonist drugs inhibited feeding in Brachionus calyciflorus in a dose-dependent manner. Most antagonist drugs caused an oscillating tachyphylaxis (drug habituation): the drug effect wore off and returned several times within an hour. Acetylcholine inhibited oviposition in Philodina acuticornis, and this effect was antagonized by all groups of anticholinergic drugs. The strongest antagonism was caused by neuromuscular blockers, and thus the cause of oviposition inhibition may be a cloacal sphincter spasm. Acetylcholinesterase inhibitory insecticides also antagonize the acetylcholine effect. Acetylcholine potentiates the anesthetic activity of ionizing local anesthetics (procaine, lidocaine) as well as that of atropine and the beta-adrenergic blocker propranolol. Muscarinic antagonists (atropine, benactyzine) and propranolol caused foot paralysis in B. calyciflorus, which is also potentiated by acetycholine. Further details of these results are given by Nogrady and Keshmirian (1986a, b).