Blood flow to the placenta and lower body in the growth-retarded guinea pig fetus

Blood flow to the placenta and lower body of control and growth retarded (IUGR) guinea pig fetuses was measured between 60-64 days of pregnancy by the microsphere technique. Further information about the hepatic blood supply and its interlobular distribution was obtained by injecting microspheres into the umbilical vein and a branch of the portal vein. Liver weight was reduced by 60% in IUGR fetuses from 5.0 +/- 0.2 to 2.0 +/- 0.1 g, compared to a decrease in body weight of 50% from 91.6 +/- 3.0 to 45.4 +/- 2.6 g. In addition, there was a proportionately greater reduction in the size of the right liver lobe. Umbilical blood flow was 10.8 +/- 1.0 ml min-1 in control fetuses and 4.9 +/- 1.2 ml.min-1 in IUGR fetuses, whilst blood flow in the portal vein was reduced from 1.4 +/- 0.1 to 0.8 +/- 0.3 ml min-1 and that in the hepatic artery from 0.6 +/- 0.1 to 0.3 +/- 0.1 ml.min-1. Since ductus venosus flow was absent or negligible, the umbilical venous return accounted for greater than 80% of the hepatic blood supply in both control and IUGR fetuses. Blood flows were, however, unequally distributed between the liver lobes. The right lobe was supplied mainly by the portal vein in IUGR fetuses as well as the controls, and received less than 6% of the umbilical venous return. No significant change occurred in total liver perfusion, which was 2.8 +/- 0.2 ml min-1 per g in control fetuses and 2.6 +/- 0.4 ml min-1 per g in IUGR fetuses. It is therefore suggested that a high rate of liver metabolism is maintained in IUGR, but by a smaller tissue mass, and that the rate of umbilical blood flow may be one factor determining the size of the liver. The relatively greater reduction in size of the right lobe in IUGR is probably the result of poor oxygenation of the portal venous blood.     

Perinatal Steroid Treatments Alter Alloparental and Affiliative Behavior in Prairie Voles

This experiment was designed to examine the hypothesis that perinatal manipulation of gonadal or adrenal steroids can alter the subsequent expression of juvenile parental (alloparenting) and affiliative behavior in prairie voles (Microtus ochrogaster). Corticosterone (PRECORT), testosterone (PRE-TP), or oil injections (PRESES) were given on Prenatal Days 12–20 or on Postnatal Days 1–6 (CORT6, TP6, or SES6, respectively). Alloparenting was reduced significantly in females in the CORT6 group and in males in the TP6 group. Sibling affiliative preferences were increased significantly in PRE-TP females and stranger preferences were increased in TP6 and CORT6 females. The results suggest timing is a critical factor determining whether hormones have a facilitative or inhibitory effect on alloparental and affiliative behavior in prairie voles. In this species, corticosterone and testosterone have similar organizational effects on affiliative behavior in females. Alloparental behavior is inhibited by postnatal corticosterone administration in females and by postnatal testosterone administration in males, whereas prenatal steroid administration had no significant effect on alloparenting in either gender.     

The nucleotide sequence of a linear plasmid of Borrelia burgdorferi reveals similarities to those of circular plasmids of other prokaryotes.

A linear plasmid of Borrelia burgdorferi had 16,927 bp, a G+C content of 23.1%, a relative deficiency of CpG dinucleotides, and open reading frames A to O. The OrfC and OrfE proteins were similar to hypothetical proteins encoded by circular plasmids of B. burgdorferi. The OrfM and OrfN proteins were similar to replication proteins of circular plasmids of other bacteria.     

Characterisation of the anti-bladder-cancer monoclonal antibody BLCA-8: Identification of its antigen as a neutral glycolipid

A monoclonal antibody, BLCA-8, was raised against the human bladder cancer cell line, UCRU-BL-17CL. By flow cytometry and immunoperoxidase staining, this antibody was found to possess high specificity for bladder tumours, some reactivity with fetal tissues, and no reactivity with normal bladder, or any normal or malignant tissue. This high specificity and the stability of the antigen to the urinary environment suggest that BLCA-8 may have potential for use as an anti-bladder-cancer therapeutic agent. By thin-layer chromatography and autoradiography, BLCA-8 was found to bind four components within the neutral lipid fraction of a bladder cancer cell line, UCRU-BL-17/23. These components hadR _F values of 0.22, 0.16/0.15 (doublet), 0.12 and 0.08, and migrated below globoside, indicating the presence of more than four sugars. By enzyme-linked immunosorbant assay and thin-layer chromatography it was found that the binding of BLCA-8 to the lipid extract was increased by both mild alkaline hydrolysis and enzymatic treatments, indicating that adjacent phospholipids and glycolipids interfere with the accessibility of the antibody-binding site. Full biochemical characterisation of the BLCA-8 antigen is currently underway.     

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.     

Genetic variation in soybean photosynthetic electron transport capacity is related to plastocyanin concentration in the chloroplast

Fifteen ancestral genotypes of United States soybean cultivars were screened for differences in photosynthetic electron transport capacity using isolated thylakoid membranes. Plants were grown in controlled environment chambers under high or low irradiance conditions. Thylakoid membranes were isolated from mature leaves. Photosynthetic electron transport was assayed as uncoupled Hill activity using 2,6-dichlorophenolindophenol (DCIP). Soybean electron transport activity was dependent on genotype and growth irradiance and ranged from 6 to 91 mmol DCIP reduced [mol chlorophyll]^–1 s^–1. Soybean plastocyanin pool size ranged from 0.1 to 1.3 mol plastocyanin [mol Photosystem I]^–1. In contrast, barley and spinach electron transport activities were 140 and 170 mmol DCIP reduced [mol chlorophyll]^–1 s^–1, respectively, with plastocyanin pool sizes of 3 to 4 mol plastocyanin [mol Photosystem I]^–1. No significant differences in the concentrations of Photosystem II, plastoquinone, cytochrome b₆f complexes, or Photosystem I were observed. Thus, genetic differences in electron transport activity were correlated with plastocyanin pool size. The results suggested that plastocyanin pool size can vary significantly and may limit photosynthetic electron transport capacity in certain species such as soybean. Soybean plastocyanin consisted of two isoforms with apparent molecular masses of 14 and 11 kDa, whereas barley and spinach plastocyanins each consisted of single polypeptides of 8 and 12 kDa, respectively.Abbreviations DAP days after planting - DCIP 2,6-dichlorophenolindophenol - LiDS lithium dodecyl sulfate - PPFD photosynthetic photon flux density (mol photons m^–2 s^–1) - PS I Photosystem I - PS II Photosystem II - P700 reaction center of Photosystem I The US Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

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.