The reproductive biology of female Père David's deer (Elaphurus davidianus)

Data for this study came from breeding records of 27 Père David's (Elaphurus davidianus) hinds maintained in large pastures and from estrous records of four hand-reared nulliparous hinds. The mean estrous cycle length ranged from 17.5 to 19.6 days. Standing estrus resembled that of other cervids, except that a low, moaning vocalization was given in response to contact, and activity (as measured by pedometers) did not increase. Mean gestation length was 183.38 ± SD 6.11 days (n = 21), and nearly all females conceived in the second and third years. The median interbirth interval was 362 days. The median birth date was April 8, and 80% of the births occurred over a 9.5-week period. Multiparous hinds gave birth an average of 20.5 days earlier in the season than primiparous hinds. There was no dimorphism in birth weight. The results are discussed in light of comparative data for other species.     

The role of litter in an old-field community: impact of litter quantity in different seasons on plant species richness and abundance

Summary We studied the effect of removing and adding plant litter in different seasons on biomass, density, and species richness in a Solidago dominated old-field community in New Jersey, USA. We removed all the naturally accumulated plant litter in November (658 g/m²) and in May (856 g/m²) and doubled the amount of litter in November and May in replicated plots (1 m²). An equal number of plots were left as controls. Litter removal and addition had little impact on total plant biomass or individual species biomass in the growing season following the manipulations. Litter removal, however, significantly increased plant densities but this varied depending upon the season of litter removal, species, and life history type. Specifically, the fall litter removal had a much greater impact than the spring litter removal suggesting that litter has its greatest impact after plant senescence in the fall and prior to major periods of early plant growth in spring. Annual species showed the greatest response, especially early in the growing season. Both spring and fall litter removal significantly increased species richness throughout the study. Litter additions in both spring and fall reduced both plant densities and species richness in June, but these differences disappeared near the end of the growing season in September. We concluded than in productive communities where litter accumulation may be substantial, litter may promote low species richness and plant density. This explanation does not invoke resource competition for the decline in species richness. Finally, we hypothesize that there may be broad thresholds of litter accumulation in different community types that may act to either increase or decrease plant yield and diversity.     

Variability of the opisthaptoral hard parts ofGyrodactylus callariatis Malmberg, 1957 (Monogenea: Gyrodactylidae) from Atlantic codGadus morhua L. in the Oslo Fjord,Norway

The present study describes the variability of the opisthaptoral hard parts ofGyrodactylus callariatis Malmberg, 1957 infesting juvenile Atlantic codGadus morhua L. in the Oslo Fjord, Norway. Samples were taken monthly or bimonthly from January 1993 to July 1994. The length of the 14 characters measured varied considerably throughout the period, and showed a significant regression on the water temperature: as the water temperature increased the length of the hard parts decreased andvice versa. There were no significant differences in the size of the hard parts between young worms (without penis) and older worms (with penis). Some of the characters (especially the anchor shaft) from parasites located on the skin and fins were significantly longer than those of parasites located in the oral cavity, pharynx and gills. Generally, the variation in the shape of the hard parts was small; the anchor root, ventral bar membrane and ventral bar processes were the most variable parts. The shape of the hard parts did not vary as a consequence of seasonal changes in the water temperature, age of the worms or site on the host.     

Functional dissection of a bean chalcone synthase gene promoter in transgenic tobacco plants reveals sequence motifs essential for floral expression

Expression of chalcone synthase (CHS), the first enzyme in the flavonoid branch of the phenylpropanoid biosynthetic pathway in plants, is induced by developmental cues and environmental stimuli. We used plant transformation technology to delineate the functional structure of the French bean CHS15 gene promoter during plant development. In the absence of an efficient transformation procedure for bean, Nicotiana tabacum was used as the model plant. CHS15 promoter activity, evaluated by measurements of -d-glucuronidase (GUS) activity, revealed a tissue-specific pattern of expression similar to that reported for CHS genes in bean. GUS activity was observed in flowers and root tips. Floral expression was confined to the pigmented part of petals and was induced in a transient fashion. Fine mapping of promoter cis-elements was accomplished using a set of promoter mutants generated by unidirectional deletions or by site-directed mutagenesis. Maximal floral and root-specific expression was found to require sequence elements located on both sides of the TATA-box. Two adjacent sequence motifs, the G-box (CACGTG) and H-box (CCTACC(N)₇CT) located near the TATA-box, were both essential for floral expression, and were also found to be important for root-specific expression. The CHS15 promoter is regulated by a complex interplay between different cis-elements and their cognate factors. The conservation of both the G-box and H-box in different CHS promoters emphasizes their importance as regulatory motifs.     

Photoaffinity labelling of a cytokinin-binding integral membrane protein in plant mitochondria

Two target polypeptides were detected by photoaffinity labelling of purified mung bean mitochondria using tritiated 2-azido-N⁶-benzylaminopurine. SDS-PAGE and fluorography of total mitochondrial proteins after the photoaffinity reaction showed a labelled 32 kDa polypeptide (intensely labelled) and a 57 kDa polypeptide (less intensely labelled). The latter was assumed to be the and/or subunit of F₁ATPase since it was the most abundant polpeptide in gels stained with Coomassie Blue. Partial purification of F₁ATPase demonstrated that the 32 kDa polypeptide was not a component of the ATPase complex. Fractionation experiments showed that the 32 kDa protein was integrally associated with mitochondrial membranes and could be enriched by simple washing and detergent extraction procedures.     

Alnus rubra nodulation capacity of soil under five species from harvested forest sites in coastal British Columbia

Nodulation of Alnus rubra seedlings after inoculation with soil from under A. rubra, Betula papyrifera. Rubus lacianutus, R. spectabilis, and R.ursinus on 2 recently harvested sites was compared. Nodulation capacity was low compared to other published reports, ranging from 0 to 18.9 infective units cm^-3 of soil and was significantly affected by the site and plant species. Nodulation capacity of soil under alder was significantly higher than under all other species except R. spectabilis, regardless of site. The lowest nodulation capacity was found in soil under B. papyrifera.Joint appointment with Dept. of Soil Science, Faculty of Agricultural Sciences     

The nervous system of Tricladida. I. Neuroanatomy ofProcerodes littoralis (Maricola,Procerodidae): An immunocytochemical study

The organization of the nervous system ofProcerodes littoralis (Tricladida, Maricola, Procerodidae) was studied by immunocytochemistry, using antibodies to authentic flatworm neuropeptide F (NPF) (Moniezia expansa). Compared to earlier investigations of the neuroanatomy of tricladid flatworms, the pattern of NPF immunoreactivity inProcerodes littoralis reveals differences in the following respects: 1. Shape and structure of the brain. 2. Number and composition of longitudinal nerve cords. 3. Shape of branches of, and transverse connections between, main ventral nerve cords. 4. Composition of the pharyngeal nervous system. The rich innervation by NPF immunoreactive (IR) fibres and cells of the subepithelial muscle layer, the pharynx musculature and the musculature of the male copulatory apparatus indicates a neurotransmitter or neuromodulatory influence on muscular activity.     

Hand dominance and bilateral asymmetry in the structure of the second metacarpal

Bilateral asymmetry in the structure of the second metacarpal was examined in relation to functional hand dominance in a large, clinically nonselected, healthy population sample from the Baltimore Longitudinal Study of Aging. Bilateral bone measurements were made from anteroposterior hand radiographs of a total of 992 individuals, 609 males and 383 females, with an age range of 19–94 years. Hand dominance was determined on the basis of personal impression. Total width and medullary width at the midshaft of the second metacarpal were measured to 0.05 mm using a Helios caliper. These two measurements were used to derive cortical thickness, cortical bone area, periosteal (total) area, medullary area, percent cortical area, and the second moment of area in the mediolateral plane. In both right and left-handed individuals, statistically significant side differences were found in the calculated bone areas and the second moment of area, with the dominant hand being larger. Cortical thickness did not show significant side-related differences for either handedness. These results show that functional handedness leads to periosteal and endosteal expansion of the second metacarpal cortex on the dominant side, increasing bone strength without increasing cortical thickness. This is the first time this pattern of asymmetry has been reported in left-handers as well as right-handers. Our results argue for the primacy of environmental (mechanical) effects in determining bilateral asymmetry of limb bone structural properties. © 1994 Wiley-Liss, Inc.