The relationship of the oestrogen and progestin receptors in the abnormal uterus of the adult anovulatory rat. Effects of neonatal treatment with testosterone propionate or clomiphene citrate.

The neonatal administration of testosterone propionate to Wistar rats resulted in anovulatory adults in persistent vaginal oestrus. Clomiphene citrate had a similar effect. In both groups of adults, hyperplasia of the uterine epithelium and occasional metaplasia was observed. The uterine nuclear and cytosol oestrogen and progestin receptors of these anovulatory rats were found to have affinities for their respective ligands similar to those of normal females. The nuclear oestrogen receptor comprised occupied and unoccupied components, as in normal females. The content of the nuclear oestrogen receptor was comparable with that of females in the late dioestrous or pro-oestrous phase. This content was higher in the clomiphene-treated group. Despite the relatively high nuclear oestrogen receptor content the content of progestin receptors, a putative index of the oestrogenic response, was lower in the treated rats than in normal adult females throughout the cycle. Administration of oestradiol to both treatment groups resulted in depletion of cytosol oestrogen receptor content 1 h later, which, however, was not reflected by an increase in the content of nuclear oestrogen receptors. There was no measurable increase in progesterone receptor content in treated rats after daily administration of oestrogen (5 microgram/rat) for 3 days. These changes in sex-hormone-receptor interactions involving an impairment of the normal oestrogenic response may be associated with the abnormal differentiation of the uterus in these sterile, anovulatory animals.     

Formaldehyde incorporation by a new methylotroph (L3)

A number of bacterial strains have been isolated and investigated in our search for a promising organism in the production of single-cell protein from methanol. Strain L3 among these isolates was identified as an obligate methylotroph which grew only on methanol and formaldehyde as the sole sources of carbon and energy. The organism also grew well in batch and chemostat mixed-substrate cultures containing methanol, formaldehyde, and formate. Although formate was not utilized as a sole carbon and energy source, it was readily taken up and oxidized by either formaldehyde- or methanol-grown cells. The organism incorporated carbon by means of the ribulose monophosphate pathway when growing on either methanol, formaldehyde, or various mixtures of C1 compounds. Its C1-oxidation enzymes included phenazine methosulfate-linked methanol and formaldehyde dehydrogenase and a nicotinamide adenine dinucleotide-linked formate dehydrogenase. Identical inhibition by formaldehyde of the first two dehydrogenases suggested that they are actually the same enzyme. The organism had a rapid growth rate, a high cell yield in the chemostat, a high protein content, and a favorable amino acid distribution for use as a source of single-cell protein. Of special interest was the ability of the organism to utilize formaldehyde via the ribulose monophosphate cycle.     

Immunohistochemical distribution of MAM-3 and MAM-6 antigens in developing salivary glands of the human fetus

Summary The immunohistochemical expression of MAM-3 and MAM-6 antigens was studied in developing human fetal salivary gland removed at autopsy of 22 normal fetuses of varying maturity (10–40 weeks of gestation). The onset of functional maturation in the fetal gland was seen at 21 weeks of gestational maturity. The acini and ducts then underwent distinct alterations in antigen expression with growth and maturation until the late developmental stage (33–40 weeks of gestation) when they resemble the adult salivary gland. The role of maturing duct cells in histogenesis of salivary gland tumours is discussed.     

尖吻蝮咬伤与心脏损害：附20例分析

本文报告尖吻蝮咬伤并心脏受累20例。经中西医结合治愈19例(95％),死亡1例(5％),并对其发病机理及治疗进行了讨论。     

The binding of rat uterine cytosol oestrogen receptors to oligodeoxythymidylate--cellulose. Its relationship to a stable form of receptor complex with separate ligand- and oligonucleotide-binding sites.

The interaction of rat uterine cytosol oestrogen-receptor complexes with the synthetic acceptor oligo(dT)--cellulose was studied. Differences in the stability of receptor complexes and their ability to bind to oligo(dT)--cellulose on storage at 4 degrees C or when exposed to increased temperatures indicated heterogeneity of steroid- and oligonucleotide-binding sites. Dilution, dialysis and (NH4)2SO4 precipitation increased the interaction of receptor complexes with oligo(dT)--cellulose (a step termed activation). This increase may be the result of the removal of low-molecular-weight cytosol components which inhibit receptor activation, dimerization to the 5 S form, which binds to oligo(dT)--cellulose, or interaction of 5 S receptor with the oligonucleotide. Cytosol oestradiol--receptor complexes exhibited biphasic dissociation kinetics. All these manipulations resulted in an increase in the proportion of the slow-dissociating component equivalent to the increase in receptor binding to oligo(dT)--cellulose. In contrast, addition of 10mM-sodium molybdate to cytosol decreased both oligo(dT)--cellulose binding and the proportion of receptor with slow dissociation kinetics. The inclusion of proteinase inhibitors did not affect interactions of receptor with oligo(dT)--cellulose nor the dissociation kinetics. These results suggest that oligo(dT)--cellulose binding may serve to quantify the proportion of cytosol receptor in an active form capable of nuclear interaction and to help to ascertain whether a receptor system is fully functional. This binding procedure could prove useful in the evaluation of oestrogen responsivity under normal and pathological conditions.     

Relationship between rate of gluconeogenesis and content of nicotinamide adenine dinucleotide in renal cortex

Gluconeogenesis in rat renal cortex was measured using tissue slices incubated with or without appropriate substrates. Immediately after incubation the tissue slices were snap-frozen and the content of oxidized nicotinamide adenine dinucleotide (NAD⁺) was determined. Incubation with 10 mM α-ketoglutarate or L-glutamate led to enhanced glucose production and an increase in tissue content of NAD⁺. Quinolinate and 3-mercaptopicolinate inhibited the rate of gluconeogenesis from L-glutamate and α-ketoglutarate respectively, and decreased the tissue levels of NAD⁺. The enhanced rate of gluconeogenesis was associated with an increase of NAD⁺ in the cytosol fraction (10⁵ × g supernatant) but not in the particulate fraction (10⁵ × g pellet) of renal cortex homogenate. Present results indicate that NAD⁺ content changes in parallel with the rate of gluconeogenesis in renal cortical tissue.     

Role of surface exclusion genes in lethal zygosis in Escherichia coli K12 mating

Summary We find that diaminopimelic acid in the recipient membrane is released into the medium during bacterial matings, indicating that membrane damage was inflicted on the recipient by the donor, probably for forming a channel for DNA transfer. When the damage is extensive, as in matings with an excess of Hfr bacteria, the F^- bacteria are killed (lethal zygosis). The transfer of a large amount of DNA in Hfr matings appears to enhance the killing. In analogous F⁺xF^- (Nal^r) matings, on the other hand, killing of F^- bacteria does not occur unless F plasmid transfer is inhibited by a substance like nalidixic acid. The F^- bacteria are killed, suggesting that F plasmids contain genes that express immunity to lethal zygosis in the recipient. For example, bacteria containing surface exclusion-deficient mutants of F plasmids, such as traS ^- and traT ^-, induce lethal zygosis in F^- bacteria and are susceptible to it. Various tra ^- polar mutants that abolish surface exclusion are also susceptible to lethal zygosis when mated with Hfr bacteria. Kinetic experiments indicate that in F⁺ (wild type) x F^- matings, immunity to lethal zygosis is expressed in the F^- recipient within 1/4 division time, whereas a complete expression of surface exclusion requires more than 1 division time. Thus, a complete change in all receptor sites seems to be required for the expression of surface exclusion.     

Rab17 Regulates Membrane Trafficking through Apical Recycling Endosomes in Polarized Epithelial Cells

A key feature of polarized epithelial cells is the ability to maintain the specific biochemical composition of the apical and basolateral plasma membrane domains while selectively allowing transport of proteins and lipids from one pole to the opposite by transcytosis. The small GTPase, rab17, a member of the rab family of regulators of intracellular transport, is specifically induced during cell polarization in the developing kidney. We here examined its intracellular distribution and function in both nonpolarized and polarized cells. By confocal immunofluorescence microscopy, rab17 colocalized with internalized transferrin in the perinuclear recycling endosome of BHK-21 cells. In polarized Eph4 cells, rab17 associated with the apical recycling endosome that has been implicated in recycling and transcytosis. The localization of rab17, therefore, strengthens the proposed homology between this compartment and the recycling endosome of nonpolarized cells. Basolateral to apical transport of two membrane-bound markers, the transferrin receptor and the FcLR 5-27 chimeric receptor, was specifically increased in Eph4 cells expressing rab17 mutants defective in either GTP binding or hydrolysis. Furthermore, the mutant proteins stimulated apical recycling of FcLR 5-27. These results support a role for rab17 in regulating traffic through the apical recycling endosome, suggesting a function in polarized sorting in epithelial cells.     

Green fluorescent protein-tagged Edwardsiella tarda reveals portal of entry in fish

The application of green fluorescent protein (GFP) to identify the portal(s) of entry of bacterial pathogens in animal hosts was studied using the fish pathogen Edwardsiella tarda and blue gourami, Trichogaster trichopterus. An immersion challenge model was utilized to mimic natural infection conditions in fish. Gastrointestinal tract, gills and the body surface of fish were found to be the sites of entry of virulent E. tarda (PPD130/91) by histological and infection kinetics studies. On the other hand, avirulent E. tarda (PPD125/87) was mainly found in the gastrointestinal tract, and the bacterial population in tissue declined over a period of 7 days.