摘要:

This paper reviews the concept of the ≪pheromone≫ as applied to behavioural studies on mammals with particular emphasis on rodents and primates. It is concluded that although the olfactory sense is very important in many representatives of these orders, the term pheromone is often used too uncritically in such species.

ISSN:0373-4137    

DOI:10.1080/11250008709355598

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

With an improved technique, evidence has been obtained of the absence of nonrandom variations of the chromosome number in the cells of male gonads of earthworms of polyploid forms, and it has been ascertained that the diploid form ofEisenia nordenskioldihas 18 chromosomes.

ISSN:0373-4137    

DOI:10.1080/11250008709355599

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Cellogel electrophoresis has been used to study isocitrate dehydrogenase (IDH), malate dehydrogenase (MDH), malic enzyme (ME), and alcohol dehydrogenase (ADH), in the housefly. Two forms of MDH (MDH, and MDH2) have been separated. These show properties similar to those ascribed to supernatant and mitochondrial MDH enzymes in other organisms. In the housefly zymograms of the mitochondrial fraction show MDH2activity only. Allelic variants of MDH1differing in thermostability and resistance top‐hydroxymercuribenzoate have been revealed by qualitative analysis. MDH2is invariant. These findings indicate that the two forms are isozymes under independent genetic control.

ISSN:0373-4137    

DOI:10.1080/11250008709355600

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The ultrastrucrure of conjugated spermatozoa of some dytiscid beetles was examined in ultrathin sections and freeze‐fracture replicas. Whereas spermatozoa ofMelanodytes pustulatusare conjugated pairwise, those ofColymbetes fuscusare conjugated in larger groups. Other members of the same subfamily (Colymbetinae) may have single or multiple spermatozoa. Features seen in the ultrathin section that were found to characterize spermatozoa from this subfamily include the hooded structure of the sperm nucleus, the absence of a ‘paraflagellar body’, a prominent mass of homogeneous appearance that seems to act as a cementing material when conjugation occurs, and the feature that the sperm nucleus turns its convex side toward the cementing material. In these respects the Colimbetinae spermatozoa seem to differ from those of the Dytiscinae subfamily.

ISSN:0373-4137    

DOI:10.1080/11250008709355601

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Spermiogenesis inCaiman crocodyluswas examined by electron microscopy. The acrosomal complex, the perforatorium and the growing axoneme of young spermatids are described. During the nuclear elongation of intermediate spermatids, two ≪manchettes≫ of microtubules were observed in addition to the acrosomal complex, perforatorium growth and chromatin condensation. At the onset of spermatid elongation, there is a set of microtubules around the nucleus and, at the end of elongation, a second set of microtubules parallel to the main axis of the cell appears. Both circular and longitudinal manchettes were observed together. In the neck‐region a striated structure of electron‐dense material is found on one side of the distal centriole. The descent of the mitochondria into che middle‐piece of the tail occurs only in the last stage of differentiation. The mitochondria are small, their cristae are irregularly arranged and the centres of the mitochondria consist of an electrondense material. Unlike most other reptilian sperm, the ring‐shaped sheath is not present in the middle‐piece. From the comparative data we conclude that the sperm of this alligator is more similar to the turtle spermatozoa than to spermatozoa of other reptiles.

ISSN:0373-4137    

DOI:10.1080/11250008709355602

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Liver mitochondria were obtained from twenty‐two male specimens ofTestudo graeca,on a monthly basis. Both mitochondrial function and ultrastructure showed a clear seasonal cycle. The results are discussed with particular reference to mechanisms controlling the circannual activity‐cycle of tortoises.

ISSN:0373-4137    

DOI:10.1080/11250008709355603

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The hemolytic activity of the coelomic fluid ofParacentrotus lividusagainst vertebrate erythrocytes was investigated. It was found that this activity corresponds to a thermo‐labile, calcinum‐dependent protein. The chemico‐physical and biological properties of this protein are compared to those of the counterparts in other echinoderm hemolytic systems. No immunological cross‐reaction could be demonstrated betweenP. lividusandHolothuria poliihemolysin.

ISSN:0373-4137    

DOI:10.1080/11250008709355604

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The appearance and distribution of acetylcholinesterase (AChE) activity in the nervous parenchyma and intracerebral capillaries inRana esculentatadpoles were studied. Histochemical data showed that at the onset of metamorphosis (stage 34), AChE activity was low and limited to a few scattered neurons. At the capillary level, AChE was found only in a few short tracts of the basal membrane. In the following stages AChE activity increased because neurons synthetized greater amounts of the enzyme and because the number of AChE‐synthetizing neurons had increased. The amount of the enzyme in the intracerebral capillaries progressively increased up to stage 50, at which point the whole basal membrane was AChE‐positive.

ISSN:0373-4137    

DOI:10.1080/11250008709355605

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Life cycle, phenology and age structure have been studied in threeDolichopodapopulations belonging to theloetitiae‐geniculataspecies complex. One of these populations inhabits a natural limestone cave (Valmarino Cave, VAL), the other two live in artificial tufa caves (Tuscolo, TUS; Tunnel of Veio, VEI).

ISSN:0373-4137    

DOI:10.1080/11250008709355606

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Populations of the water frog,Rana esculentacomplex, in peninsular Italy and Sicily are composed of two distinct forms termed ≪Southern Italian hybrid≫ and ≪Southern Italian non‐hybrid≫. The presence and the relative percentages of the two forms vary from site to site. Morphological and biochemical features of five frog populations of peninsular Italy (Colfiorito, Lesina, Castelvolturno, Monticchio and Cecita) and of one frog population of Sicily (Adrano) revealed only non‐hybrid individuals on peninsular Italy, and both hybrid and non‐hybrid specimens at Adrano. These data integrate previous observations on Italian water frogs and help define the local composition of these anuran populations.

ISSN:0373-4137    

DOI:10.1080/11250008709355607

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor