Ultrasonic vocalizations of adult male Foxp2‐mutant mice: behavioral contexts of arousal and emotion

Adult mouse ultrasonic vocalizations (USVs) occur in multiple behavioral and stimulus contexts associated with various levels of arousal, emotion and social interaction. Here, in three experiments of increasing stimulus intensity (water; female urine; male interacting with adult female), we tested the hypothesis that USVs of adult males express the strength of arousal and emotion via different USV parameters (18 parameters analyzed). Furthermore, we analyzed two mouse lines with heterozygous Foxp2 mutations (R552H missense, S321X nonsense), known to produce severe speech and language disorders in humans. These experiments allowed us to test whether intact Foxp2 function is necessary for developing full adult USV repertoires, and whether mutations of this gene influence instinctive vocal expressions based on arousal and emotion. The results suggest that USV calling rate characterizes the arousal level, while sound pressure and spectrotemporal call complexity (overtones/harmonics, type of frequency jumps) may provide indices of levels of positive emotion. The presence of Foxp2 mutations did not qualitatively affect the USVs; all USV types that were found in wild‐type animals also occurred in heterozygous mutants. However, mice with Foxp2 mutations displayed quantitative differences in USVs as compared to wild‐types, and these changes were context dependent. Compared to wild‐type animals, heterozygous mutants emitted mainly longer and louder USVs at higher minimum frequencies with a higher occurrence rate of overtones/harmonics and complex frequency jump types. We discuss possible hypotheses about Foxp2 influence on emotional vocal expressions, which can be investigated in future experiments using selective knockdown of Foxp2 in specific brain circuits.     

A human monoclonal antibody against small envelope protein of hepatitis B virus with potent neutralization effect

Hepatitis B virus (HBV) produces large (L), middle (M), and small (S) envelope proteins, alternatively referred to as hepatitis B surface antigen (HBsAg). Currently, yeast-derived S protein serves as the preventive vaccine, while hepatitis B immune globulin (HBIG) concentrated from pooled plasma of vaccine recipients is employed for post-exposure prophylaxis. However, only a small proportion of the antibodies in HBIG are HBV specific. In the present study, a human monoclonal anti-S antibody (G12) was developed, produced under GLP conditions, and subjected to a panel of functional assays. In vitro results demonstrated high affinity of G12 for the S protein (K_D = 7.56 nM). It reacted with envelope proteins of all 7 HBV genotypes tested (A-F, H) by immunofluorescent staining, and more than 97% of HBsAg-positive patient serum samples by enzyme-linked immunosorbent assay. G12 recognized a conformational epitope, although the exact sequence remains unknown. Strikingly, G12 was at least 1,000-fold more potent than HBIG in neutralizing HBV infectivity in both HepaRG cell line and HepG2 cells reconstituted with the HBV receptor. In a transgenic mouse model of HBV persistence, a single peritoneal injection of G12 markedly diminished serum HBsAg titers in all 7 mice, which was sustained for the observation period of 144 d in mice with low pre-treatment levels. While the therapeutic potential of G12 warrants further investigation using a large number of animals, G12 is a potent neutralizing human monoclonal antibody and a promising candidate to replace or supplement HBIG in the prevention of HBV infection.     

Intrauterine trophoblast migration: A comparative view of humans and rodents

ABSTRACT

Trophoblast migration and invasion through the decidua and maternal uterine spiral arteries are crucial events in placentation. During this process, invasive trophoblast replace vascular endothelial cells as the uterine arteries are remodeled to form more permissive vessels that facilitate adequate blood flow to the growing fetus. Placentation failures resulting from either extensive or shallow trophoblastic invasion can cause pregnancy complications such as preeclampsia, intrauterine growth restriction, placenta creta, gestational trophoblastic disease and even maternal or fetal death. Consequently, the use of experimental animal models such as rats and mice has led to great progress in recent years with regards to the identification of mechanisms and factors that control trophoblast migration kinetics. This review aims to perform a comparative analysis of placentation and the mechanisms and factors that coordinate intrauterine trophoblast migration in humans, rats and mice under physiological and pathological conditions.     

Temporal synthesis of mitochondrial proteins from mouse epididymal spermatozoa

Mitochondria from ejaculated bovine spermatozoa contain a group of polypeptides ranging in molecular weights from 13,000 to 35,000 not found in other bovine or murine testicular mitochondria [Hecht and Bradley, 1981]. These proteins are present in the mitochondria isolated from both epididymal and ejaculated spermatozoa. To establish when during epididymal transport, spermiogenesis, and/or meiosis these proteins are synthesized, the synthesis intervals for the mitochondrial proteins from cauda epididymal spermatozoa were established following intratesticular injection of (³⁵S)methionine. Mice were killed every third day over a 33-day period and cauda epididymal spermatozoa were fractionated into mitochondrial and head components. Radioactivity in each fraction was monitored by liquid scintillation counting. Maximal incorporation was observed during spermiogenesis, although substantial amounts of protein were synthesized during meiosis. Analysis of the mitochondrial polypeptides by gel electrophoresis revealed that many polypeptides such as the cysteine-rich structural protein of the mitochondrial capsule were synthesized over prolonged intervals of spermiogenesis and meiosis rather than in a brief specific time period. These results suggest that spermatozoal mitochondria are produced by a sequential substitution of new proteins into the differentiating mitochondria rather than the abrupt appearance of a new class of mitochondria during spermatogenesis.     

The process of population increase and patterns of resource utilization of two spider mites,Oligonychus ununguis (Jacobi) andPanonychus citri (McGregor), under experimental conditions (Acari: Tetranychidae)

Summary Pattern of population growth and characteristics of habitat utilization and of migration by two species of spider mites were studied under experimental conditions. The population growth ofOligonychus ununguis (Jacobi) on a chestnut occurred only on a single mite-release leaf over a long period, and few individuals moved away. Most of the 2nd progeny generation females of this species emigrated from the mite-release leaf as well as the sapling by means of ballooning threads. During this growth period, population density on the mite-release leaf levelled off, whereas that on the sapling increased. In contrast, the foundress ofPanonychus citri (McGregor) on citrus actively moved over several neighbouring leaves, and until the 2nd progeny generation females emerged, individuals were distributed over all the sapling leaves by means of walking. Emigration from the sapling was not observed until the 2nd progeny females emerged, and after that the mites emigrated by means of ballooning threads. The population density ofP. citri on the sapling levelled off and was rather decreased on the mite-release leaf at the time of mite emigration. Comparing the changing pattern of the relative degree of aggregation (m ^*/m) measured in two different units between these two species, the pattern ofm ^*/m in 1 cm² on the mite release leaf inO. ununguis resembled that of the unit of leaves on the sapling inP. citri. This result as well as behavioural observations indicate that migration ofO. ununguis is the movement from leaf to leaf and that ofP. citri from sapling to sapling. It is, therefore, concluded that the boundary of the microhabitat is a single leaf forO. ununguis but sapling or foliage forP. citri. This work was presented in Annual Meeting of Jap. Soc. Appl. Ent. Zool., 1981 in Okayama.     

Social behavior of early emerging males of a Japanese paper wasp,Polistes chinensis antennalis (Hymenoptera: Vespidae)

Summary Five cases of the early emergence of males in a Japanese paper wasp,Polistes chinensis antennalis, in which male emerged together with the first group of workers, were described. In one case of the five where the queen disappeared before the emergence of male, worker(s) produced female offspring. The frequency of the nests where the early emergence of male was observed was 16.7% (5/30 nests). In two colonies, worker(s) and/or queen chased off males. But in an orphan nest where worker(s) produced female offspring, the dominance order among workers which was similar to that of colony without male was observed. The significance of the early emergence of male in the social evolution of wasps was discussed.     

A brachylaimid trematode from marsupial mice with observations on its life cycle

A species of digenetic trematode, Brachylaime antechini (Family Brachylaimidae), is described from adult worms recovered from the intestine and rectum of two species of marsupial mice, Antechinus stuartii(10 of 56 infected) and Antechinus swainsonii (2 of 5 infected). On experimental evidence unencysted metacercariae from the kidney of a terrestrial gastropod, Strangesta capillacea, are considered to be larval stages of Brachylaime antechini. Miracidia, sporocysts and cercariae have not been recovered, but circumstantial evidence suggests that Strangesta capillacea fulfils the role of first intermediate host. Brachylaime antechini most closely resembles Brachylaime chiapensis, a parasite of deer mice in Mexico.     

Biochemical Correlates of Myelination in Brain and Spinal Cord of Mice Heterozygous for the Jimpy Gene

Brain and spinal cord of female mice heterozygous for the jimpy gene were analyzed during development for activity of ceramide galactosyl transferase (CGT) and for levels of myelin basic protein (MBP). CGT activity was low at 13-14 days in brains of heterozygous jimpy females but showed normal levels by 31-36 days, in agreement with our earlier study of this enzyme. In cord, CGT activity was normal or slightly above normal at all ages studied, from 13-14 days into adulthood. In both brain and cord, decreased levels of MBP were observed at 13 days; by 100 days, amounts of MBP approached normal levels. Proven female carriers of the jimpy gene also showed normal levels of CGT activity, MBP, and isolated myelin at 200-250 days of age in both brain and cord. These biochemical findings agree with previous morphologic measurements in cord demonstrating deficits in myelin at early ages but compensation by 100 days. Our results show that compensation occurs earlier in cord than in brain and that levels of MBP show a closer correlation than CGT activity with amounts of myelin, as measured by either morphometric analysis or direct isolation.