Heterochromatin and cytogenetic polymorphisms in Cebus apella (Cebidae,Platyrrhini)

Cytogenetic studies have been carried out in 39 specimens of C. apella of different origins. Three different morphologies, one affecting the long arm of chromosome 4 and two affecting pair 17, have been detected. In each case, they can be related by paracentric inversions. Heterochromatin polymorphisms affecting terminal or interstitial C+ regions have also been observed. The length of the terminal heterochromatic region in the long arms of chromosome 11 is variable in C. apella sp., in C. a. paraguayanus and absent in the C. a. nigritus specimens studied. Interstitial C + bands can be observed in the long arms of the biarmed chromosomes 4 and 6, and in the long arms of the acrocentric pairs 12, 13, 17, 18, 19, 20, and 21. Interstitial C + bands in the long arms of chromosomes 4, 12, 17, and 19 are present in all animals studied, although their size is variable, especially in the case of chromosomes 17 and 19. © 1995 Wiley-Liss, Inc.     

Gelled diet for screwworm (Diptera: Calliphoridae) mass production

A rearing system based on a diet gelled with Water-Lock G-400, a synthetic superabsorbent (poly(2-propenamide-co-2-propenoic acid, sodium salt)) (WL), was compared with the standard rearing system (liquid diet suspended in acetate fibers) for the mass production of screwworms, Cochliomyia hominivorax (Coquerel). The WL rearing system yielded 2% heavier pupae, 32% higher egg to pupa survival, and required 54% less diet and 88% less labor than the standard rearing system. Other advantages of the WL system include reduced susceptibility to suboptimal environmental conditions and labor practices and characteristics conducive to centralization and mechanization of rearing procedures.     

Role of loud calls in brown howlers,Alouatta fusca

The loud calls of brown howler monkeys were studied during a year at the Santa Genebra Reserve, in southeastern Brazil. The study group emitted roars and barks on a total of 47 occasions, the majority of which (92%) were restricted to intergroup visual encounters. Loud calls were also elicited by the roars of distant groups (6%) and during intragroup agonistic interactions (2%). Intergroup visual encounters (n = 42) occurred predominantly in seldom used quadrats of the study group home range. In these instances, the loud calls were produced chiefly by the adult male alone (69% of cases), while the study group's two adult females joined the male in the remaining cases. Intergroup physical aggression, such as chase and displacement, was observed during 15 encounters (35% of cases). A dawn chorus does not occur in Santa Genebra—the loud calls were heard most frequently in mid-morning and again during mid-afternoon—and they were more abundant during the dry season, when the availability of food (new leaves) in the forest was lower. The data presented here provide some support for the hypothesis that roars of howler adult males are used in assessment of opponents, providing an alternative to energetically expensive chases and fights. However, given the relatively high rate of physical aggression observed during intergroup encounters, a result probably related to the high density of howlers and the consequent high frequency of intergroup encounters observed in this forest (0.7/day), ritualized aggression, in the form of loud calling, is apparently often insufficient to settle disputes. © 1995 Wiley-Liss, Inc.     

Effects of intermittent aeration periods on a structured-bed reactor continuously fed on the post-treatment of sewage anaerobic effluent

Bioprocess and Biosystems Engineering - This study assessed the simultaneous nitrification and denitrification processes and remaining organic matter removal from anaerobic reactor effluent...     

Ultrastructural changes in the renal filtration barrier during hibernation of the common dormouse (Eliomys quercinus L.)

We have studied kidney samples of 16 garden dormouses (Eliomys quercinus L.) divided into two groups, 8 hibernating and 8 non-hibernating. Hibernation produces structural modifications in the glomerular ultrafilter: (1) the endothelial pores decrease in number and size; (2) the podocytic food processes increase in number and the slit pores decrease in size; (3) in the basement membrane there are no structural morphological modifications. In short, we could say that the permeability of the glomerular ultrafilter decreases during hibernation. This fact helps to understand the decrease in the rate of urine formation that takes place in the presence of a low body temperature and a metabolic depression.