The 24-, 48- and 96-h LC50 of nitrite and the effects on reactive oxygen intermediates (ROIs) in haemocytes and muscle, superoxide dismutase (SOD) activity, catalase (CAT) activity, glutathione peroxidase (GPX) activity, in muscle of Macrobrachium nipponense exposed to ambient nitrite were investigated. The 24-, 48- and 96-h LC50 values of nitrite at pH 8.0 were 46, 26 and 13.3 mg l-1. A significantly increased ROIs value was found in prawn (P<0.05) exposed to nitrite shock and increased with increased ambient nitrite concentration. Exposure to a sublethal concentration of nitrite for 24 h, increased ROIs by 97% compared with that of prawn exposed to control nitrite concentration, whereas SOD, CAT and GPX activity decreased 67%, 80.6% and 82.7%, respectively. The results showed that an imbalance between prooxidant forces and antioxidant defenses is one of the toxicity mechanisms of nitrite on prawn.

This paper deals with the developmental process of thermoregulation. From an ecologicalp oint of view, it establishes a mathematical model for postnatal development of thermoregulation, and proposes a new index of homeothermy ability. The model is used to predict homenthermy ability at any time of postnatal development for root vole and other species.

Using induction of Fos as an index, we studied cellular activation patterns in the accessory olfactory bulb (AOB) and main olfactory bulb (MOB) of Mandarin voles (Microtus mandarinus (Milne-Edwards, 1871)) following their exposure to beddings soiled by different sexes. Male and female Mandarin voles that were exposed to beddings soiled by the opposite sex produced significantly more Fos-immunoreactive (Fos-ir) neurons in the anterior portion of the AOB and significantly fewer Fos-ir neurons in the posterior portion of the AOB than voles exposed to beddings soiled by the same sex. Furthermore, male and female Mandarin voles exposed to bedding soiled by different sex produced different numbers of Fos-ir cells in MOB. Mandarin voles exposed to beddings soiled by the opposite sex produced significantly more Fos-ir neurons in MOB than voles exposed to beddings soiled by the same sex. Our results establish that Mandarin voles of each sex showed different cellular activation patterns in AOB and MOB following exposures to sex-specific beddings. We suggest that both AOB and MOB were involved in sexual activities induced by chemosensory signals. Resume: En utilisant comme indice l’induction de Fos, nous avons etudie les patrons d’activation cellulaire du bulbe olfactif accessoire (AOB) et du bulbe olfactif principal (MOB) chez des campagnols mandarins (Microtus mandarinus (Milne-Edwards, 1871)) apres une exposition a la litiere souillee des deux sexes. Apres une exposition a la litiere souillee du sexe oppose, les campagnols mandarins males et femelles produisent significativement plus de neurones Fos-positifs dans la portion ante´rieure de leur AOB et significativement moins de neurones Fos-positifs dans la portion poste´rieure que les campagnols exposes a la litiere souillee d’animaux du meme sexe. De plus, les campagnols mandarins males et femelles exposes a la litiere souillee du sexe oppose produisent des nombres differents de cellules Fos-positives dans leur MOB. Les campagnols mandarins exposes a la litiere souillee du sexe oppose produisent significativement plus de neurons Fos-positifs dans leur MOB que les campagnols exposes a la litiere souillee du meme sexe. Nos resultats demontrent que les campagnols mandarins des deux sexes possedent des patrons d’activation cellulaire differents dans leur AOB et leur MOB apres une exposition a la litiere d’un sexe en particulier. Nous croyons que tant le AOB que le MOB sont impliques dans les activites sexuelles induites par les signaux chimiques sensibles.

We examined the effects of temperature and photoperiod on metabolic thermogenesis and the thermogenic characteristics of brown adipose tissue in plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus), the dominant species of small mammals in the alpine meadow ecosystems on the Qinghai-Tibetan Plateau. Pikas and voles were acclimated in the following groups: (1) Long day-warm temperature (16L:8D, 23

l. Oxygen consumption and body temperatures of 32 juvenile root voles (Microtus oeconomus) of different ages (in days) were measured at ambient temperatures (Ta) of 10, 20 and 30