Fertility interactions in Drosophila: Theoretical model and experimental tests

The results of 11 experiments with Drosophila species show that fertility is not a reducible property: the fertility of a mating pair cannot be predicted from the average fertility of the two genotypes involved. We propose a model of fertility selection that does not assume additivity (or multiplicativity) but assumes random mating and that the genotypic frequencies are in Hardy-Weinberg equilibrium. Numerical simulations show that removal of the assumption of Hardy-Weinberg frequencies does not significantly change the equilibrium frequencies predicted by the model.     

Growth and production of O+ bream (Abramis brama), O+ roach (Rutilus rutilus) and O+ carp (Cyprinus carpio) in 10 drainable 0.1 Ha ponds

In ten 0.1 ha drainable ponds O⁺ cyprinids were stocked to assess their impact on the aquatic community. Bream and roach were stocked in early June, 1986, and carp in early July, 1986. The ponds were drained mid November, 1986. The relationship between the fish community and its food resource was estimated in terms of production and consumption with use of the data on growth and mortality of the fish. The average gross production of the fish species in the ten ponds (48.4 kg during the experiment) was dominated by the carp (58.5%). A minimum estimate of the food consumption of the O⁺ cyprinids is 760 kJ.m^–2. The average production of bream and roach was much lower than that of carp due to a higher mortality and a more specialized feeding pattern. The gross productions of carp, bream and roach in the ten ponds were not significantly related, although stomach analysis showed diet overlap between the carp and the bream.     

从我国成人手足口病患者疱液中首次分离出肠道病毒71型

本文报道了从我国手足口病(HFMD)患者疱液中肠道病毒71(E71)型H株的分离和鉴定。该株病毒可在原代人胚肺(HEL)细胞、MA104细胞、BSC细胞中生长繁殖,导致典型的肠道病毒CPE出现。将H株接种乳鼠后出现肢体麻痹、第6天开始死亡。电镜下可见感染H株的BSC细胞胞浆中出现大量的结晶状排列的成熟病毒颗粒,直径约25nm。患者双份血清中有对H株4倍增高的中和抗体存在。采用100抗体单位的抗Cox A5、7、9、16、E70、E71抗体和50抗体单位的LBM组合血清A-H以及抗E71BrCr株MeAb P27对H株进行中和试验时,H株可被抗E71血清和MeAb P27所中和。抗E71抗体对H株的最低有效中和作用为1.6抗体单位,MeAb P27对H株的有效中和作用是64抗体单位。其它血清则无此中和作用。然而,在鉴定过程中发现,高滴度的抗Cox A16抗体(200抗体单位以上)也显出有中和H株的作用,提示我们所分离的H株含有与Cox A16的型间共同抗原。     

Type I protein kinase C isozyme in the visual-information-processing pathway of monkey brain

Previously using PKC isozyme-specific antibodies for immunoblot analysis, we demonstrated the heterogeneous distribution of PKC isozymes in various regions of monkey and rat brains and that type I PKC was most abundant in cerebellum, hippocampus, amygdala, and cerebral cortex (Huang et al.: J Biol Chem 262:15714-15720, 1987). Using these antibodies, we have also demonstrated that type I, II, and III PKC are products of PKC genes gamma, beta, and alpha, respectively (Huang et al.: Biochem Biophys Res Commun 149:946-952, 1987). By immunocytochemical analysis, type I PKC-specific antibody showed strong reactivity in various types of neuron in hippocampal formation, amygdala, cerebellum, and neocortex. In hippocampal formation, granule cells of dentate gyrus and pyramidal cells of hippocampus were heavily stained. By immunoblot analysis, relative levels of PKC isozymes in several areas of monkey cerebral cortex involved in the visual information processing and storage were determined. Both type II and III PKCs appeared to be evenly distributed and at moderate levels, type I PKC formed a gradient of increasing concentration rostral along the cerebral cortex of occipital to temporal and then to the limbic areas. Neurobehavioral studies have demonstrated that the neocortical and limbic areas of the anterior and medial temporal regions participate more directly than the striate, prestriate, and posterior temporal regions in the storage of visual representations and that both hippocampus and amygdala are important in the memory formation. As type I PKC is present at high levels in hippocampus, amygdala, and anterior temporal lobe, we predict that the type I protein kinase C may participate in the plastic changes important for mnemonic function.     

Climate and vegetation in China II. Distribution of main vegetation types and thermal climate

The authors examined relationships between Kira's warmth index (WI) and four other important thermal indices: the sums of daily mean temperatures above 5°C and 10°C, Thornthwaite's potential evapotranspiration (PE) and Holdridge's annual biotemperature. The thermal records of 671 meteorological stations evenly located all over China were used to make these comparisons. Close correlations were found within the four relationships, and accordingly WI was used to analyse the thermal distributions of the main vegetation types. Vegetation types around the 671 stations were read from a vegetation map with a scale of 1/4000000. Vegetation types at 269 stations corresponded to the natural or seminatural vegetation, and 29 vegetation types were distinguished by arranging the 269 data into the same or similar types. The geographical distribution of these 29 types and the corresponding main climatic features were described. The relations between WI and distribution of these vegetation types were discussed in detail. As a result, WI values (°C month) corresponding to the vegetation zones could be summarized as follows: (1) arctic or alpine vegetation zone: 0–15; (2) boreal or subalpine vegetation zone: 15-(50–55); (3) cool-temperate vegetation zone: (50–55)–(80–90); (4) warm-temperate vegetation zone: (80–90)–(170–180). These values almost coincided with Kira's values. Chinese postgraduate student in Japan sent by the Chinese Government.     

The evolution of male-female dimorphism: Older than sex?

This contribution considers the evolution of a dimorphism with respect to cell fusion characteristics in a population of primitive cells. These cells reproduce exclusively asexually. The evolution towards asymmetric fusion behaviour of cells is driven by selection promoting horizontal transfer of an endosymbiontic replicator. It is concluded that evolution of asymmetric cell fusion in this scenario is more likely than evolution of sexual differentiation in a sexually reproducing population. Pre-existing dimorphism with respect to cell fusion may thus have been the basis for the establishment of sexual differentiation at the level of gamete fusion, and this in turn is fundamental to the evolution of two different sexes, male and female.     

Activity dependent characteristics of fast and slow muscle: biochemical and histochemical considerations

The effects of denervation and hindlimb suspension induced disuse on concentrations of ATP, phosphocreatine (PC), and fiber type profile were investigated in slow twitch soleus and fast twitch extensor digitorum longus (EDL) muscles. The results show that the soleus and EDL muscles differ in their dependency on loadbearing as a stimulus for maintaining normal energy metabolism and the biochemical and morphological characteristics of muscle fibers. As determined by R-P methodology, suspension reduced ATP and PC concentrations of the soleus to 26% and 56%, respectively, while, in EDL only, PC is reduced to 71% of control with no change in ATP. Both muscles, however, show identical losses in ATP and PC following denervation. The energy charge, an indicator of Pi availability in muscle was reduced significantly in both denervated muscles to 82% and 85% in soleus and EDL, respectively. No significant reduction of the energy charge was seen in the muscles from suspended rats. Thus, in parallel with the indirect regulation through muscle loadbearing, the nerve can effectively modulate the levels of high-energy phosphates more directly by some regulatory mechanisms independent of muscle type. Denervation and suspension disuse increased the proportion of type 2 fibers in the soleus with a concomitant decrease in type 1 fibers and a relative rise in the number of very small diameter fibers. The EDL showed only variation in fiber size.     

Virulence of Salmonella enteritidis phage type 4 is related to the possession of a 38 MDa plasmid

Nine strains of Salmonella enteritidis phage type 4 were examined for virulence in BALB/c mice. The possession of a 38 MDa plasmid was necessary for full virulence. Strains carrying this plasmid had LD50 values of less than 20 bacteria whilst plasmid-free strains had LD50 values of greater than 10(6) bacteria when challenged intraperitoneally. Pathogenesis of disease involved the widespread distribution of bacteria throughout the tissues. Possession of the 38 MDa plasmid could not be linked with the ability of strains to express novel outer membrane proteins, to produce toxins affecting Vero, Y1, HeLa, Henle or HEp-2 cells, or to invade HEp-2 cells. Furthermore, the 38 MDa plasmid did not encode an aerobactin-mediated iron uptake system or the production of a haemolysin. Strains of S. enteritidis PT4 isolated in 1967, 1978 or 1979 and possessing the 38 MDa plasmid showed the same virulence properties as the current plasmid-carrying strains. This suggests that the enhanced virulence of the current strains for poultry is unlikely to be the result of changes in the 38 MDa plasmid.     

Food habits and prey selection of three species of groupers from the genus Cephalopholis (Serranidae: Teleostei)

Synopsis This paper describes a study performed in the Gulf of Aqaba on food selectivity and hunting behaviour of three species of sympatric fish from the genusCephalopholis. These fishes occur in the shallow-water coral habitats of the Red Sea and feed on fishes and invertebrates. Of these,C. argus andC. miniata prefer selected fish species (95 and 86% of their diet respectively), whereasC. hemistiktos consumes more invertebrates (36%) and is less selective with respect to fish species. All three species employ various techniques to catch their prey and in situations where their elected food is absent they readily switch to substitute prey species.     

Feeding habits of Japanese butterfyfishes (Chaetodontidae)

Synopsis Stomach content data from 32 species of Japanese butterflyfishes of the family Chaetodontidae were used to classify them into feeding groups and to determine their important food resources. Four major feeding groups were distinguished: (1) obligative coral feeders which prey exclusively or mostly on Scleractinian corals, (2) facultative coral feeders that take both corals and other benthic organisms, (3) noncoralline invertebrate feeders which consume benthic invertebrates other than corals, and (4) zooplankton feeders. Ten species representing 31% of the butterflyfishes belong to the first category. The second and third categories include 13 (41%) and 8 (25%) species, respectively. The fourth category is represented by only one species which picks individual zooplankters, especially calanoid copepods, in midwater above the reefs. Facultative coral feeders consumed varying quantities of scleractinians (from 2 to 74% of food volume), along with a variety of benthic organisms including algae, alcyonarians, sea anemones, sedentary polychaetes, sponges, hydroids, etc. Noncoralline invertebrate feeders, on the other hand, tend to have low diversified diets, predominated by one prey item such as sea anemones, zoanthideans, polychaetes, or colonial ascidians. These dietary data suggest that scleractinian corals are the most important food resource for the Japanese butterflyfishes, and next important are sea anemones, sedentary polychaetes, alcyonarians, and algae.