Ovarian follicular activity and hormonal profile during estrous cycle in cows: the development of 2 versus 3 waves

Most estrous cycles in cows consist of 2 or 3 waves of follicular activity. Waves of ovarian follicular development comprise the growth of dominant follicles some of which become ovulatory and the others are anovulatory. Ovarian follicular activity in cows during estrous cycle was studied with a special reference to follicular waves and the circulating concentrations of estradiol and progesterone. Transrectal ultrasound examination was carried out during 14 interovulatory intervals in 7 cows. Ovarian follicular activity was recorded together with assessment of serum estradiol and progesterone concentrations. Three-wave versus two-wave interovulatory intervals was observed in 71.4% of cows. The 3-wave interovulatory intervals differed from 2-wave intervals in: 1) earlier emergence of the dominant follicles, 2) longer in length, and 3) shorter interval from emergence to ovulation. There was a progressive increase in follicular size and estradiol production during growth phase of each wave. A drop in estradiol concentration was observed during the static phase of dominant anovulatory follicles. The size of the ovulatory follicle was always greater and produced higher estradiol compared with the anovulatory follicle. In conclusion, there was a predominance of 3-wave follicular activity that was associated with an increase in length of interovulatory intervals. A dominant anovulatory follicle during its static phase may initiate the emergence of a subsequent wave. Follicular size and estradiol concentration may have an important role in controlling follicular development and in determining whether an estrous cycle will have 2 or 3-waves.     

Insulin-like growth factor I receptor is downregulated after alveolarization in an apoptotic fibroblast subset

After alveolar formation, >20% of interstitial lung fibroblasts undergo apoptosis, a process that is of critical importance for normal lung maturation. The immature lung contains two morphologically distinct fibroblast populations, lipid-filled interstitial fibroblasts (LIF) and non-LIF (NLIF), which differ with respect to contractile protein content, proliferative capacity, and expression of mRNAs for fibronectin and types I and III collagen, but not tropoelastin. After alveolarization, apoptosis occurs in only one fibroblast population, the LIF. Using flow cytometry to analyze fibroblasts stained with a lipophilic, fluorescent dye, we identified a subset, designated LIF(-), that contained fewer lipid droplets. Unlike LIF that retain lipid, LIF(+), the LIF(-) do not undergo apoptosis after alveolarization. In LIF(+), apoptosis was correlated with downregulation of insulin-like growth factor I receptor (IGF-IR) mRNA and cell surface protein expression. Treatment with anti-IGF-IR decreased total lung fibroblast survival (P = 0.05) as did treatment with the phosphatidylinositol 3-kinase inhibitor LY-294002 and the ras-raf-mitogen-activated protein kinase inhibitor PD-98059 (P < 0.002), which block IGF-I/insulin receptor survival pathways. These observations implicate downregulation of IGF-IR expression in fibroblast apoptosis after alveolar formation.     

Recombinant pICln Forms Highly Cation-selective Channels when Reconstituted into Artificial and Biological Membranes

pI_Cln has been proposed to be the swelling-activated anion channel responsible for I_{Cl, swell}, or a channel regulator. We tested the anion channel hypothesis by reconstituting recombinant pI_Cln into artificial and biological membranes. Single channels were observed when pI_Cln was reconstituted into planar lipid bilayers. In the presence of symmetrical 300 mM KCl, the channels had a high open probability and a slope conductance of 48 pS, and were outwardly rectifying. Reduction of trans KCl to 50 mM shifted the reversal potential by −31.2 ± 0.06 mV, demonstrating that the channel is at least seven times more selective for cations than for anions. Consistent with this finding, channel conductance was unaffected by substitution of Cl⁻ with glutamate, but was undetectable when K⁺ was replaced by N-methyl-d-glucamine. Reconstitution of pI_Cln into liposomes increased ⁸⁶Rb⁺ uptake by three- to fourfold, but had no effect on ³⁶Cl⁻ uptake. Phosphorylation of pI_Cln with casein kinase II or mutation of G54, G56, and G58 to alanine decreased channel open probability and ⁸⁶Rb⁺ uptake. When added to the external medium bathing Sf9 cells, pI_Cln inserted into the plasma membrane and increased cell cation permeability. Taken together, these observations demonstrate that channel activity is due to pI_Cln and not minor contaminant proteins. However, these findings do not support the hypothesis that pI_Cln is the anion-selective I_{Cl, swell} channel. The observed cation channel activity may reflect an as yet to be defined physiological function of pI_Cln, or may be a consequence of in vitro reconstitution of purified, recombinant protein.     

Glucosylated N-acetyllactosamine O-antigen chain in the lipopolysaccharide from Helicobacter pylori strain UA861

The O-antigen chain from the lipopolysaccharide of Helicobacter pylori strain UA861 was determined to be composed of an elongated type 2 N - acetyllactosamine backbone, -[-->3)-beta-D-Gal-(1-->4)-beta-D-GlcNAc-(1- ]n-->, with approximately half of the GlcNAc units carrying a terminal alpha-d-Glc residue at the O -6 position. The O-chain of H.pylori UA861 was terminated by a N -acetyllactosamine [beta-D-Gal-(1-->4)-beta-D- GlcNAc] (LacNAc) epitope and did not express terminal Lewis X or Lewis Y blood-group determinants as previously found in other H.pylori strains. The absence of terminal Lewis X and Lewis Y blood-group epitopes and the replacement of Fuc by Glc as a side chain in the O- chain of H.pylori UA861 represents yet another type of lipopolysaccharide structure from H.pylori species. These structural differences in H.pylori lipopolysaccharide molecules carry implications with regard to possible different pathogenic events between strains and respective hosts.      

Evaluating the impact of biodiversity offsetting on native vegetation

Biodiversity offsetting is a globally influential policy mechanism for reconciling trade-offs between development and biodiversity loss. However, there is little robust evidence of its effectiveness. We evaluated the outcomes of a jurisdictional offsetting policy (Victoria, Australia). Offsets under Victoria's Native Vegetation Framework (2002–2013) aimed to prevent loss and degradation of remnant vegetation, and generate gains in vegetation extent and quality. We categorised offsets into those with near-complete baseline woody vegetation cover (“avoided loss”, 2702 ha) and with incomplete cover (“regeneration”, 501 ha), and evaluated impacts on woody vegetation extent from 2008 to 2018. We used two approaches to estimate the counterfactual. First, we used statistical matching on biophysical covariates: a common approach in conservation impact evaluation, but which risks ignoring potentially important psychosocial confounders. Second, we compared changes in offsets with changes in sites that were not offsets for the study duration but were later enrolled as offsets, to partially account for self-selection bias (where landholders enrolling land may have shared characteristics affecting how they manage land). Matching on biophysical covariates, we estimated that regeneration offsets increased woody vegetation extent by 1.9%–3.6%/year more than non-offset sites (138–180 ha from 2008 to 2018) but this effect weakened with the second approach (0.3%–1.9%/year more than non-offset sites; 19–97 ha from 2008 to 2018) and disappeared when a single outlier land parcel was removed. Neither approach detected any impact of avoided loss offsets. We cannot conclusively demonstrate whether the policy goal of ‘net gain’ (NG) was achieved because of data limitations. However, given our evidence that the majority of increases in woody vegetation extent were not additional (would have happened without the scheme), a NG outcome seems unlikely. The results highlight the importance of considering self-selection bias in the design and evaluation of regulatory biodiversity offsetting policy, and the challenges of conducting robust impact evaluations of jurisdictional biodiversity offsetting policies.     

Interactions between stochastic and deterministic processes in stream fish community assembly

Synopsis Numerous studies have attempted to determine whether stream fish communities are structured primarily by deterministic or stochastic processes. Previous work has assumed that stream fish communities will show either persistence about an equilibrium because of strong density-dependent processes or random variation in structure as a result of environmental stochasticity. In a 10-year study of a California stream, fish community structure changed under the influence of storm-induced high discharge events that impacted recruitment. Species' relative abundances were altered as pre-recruitment stream discharges differentially influenced year-class strength among species with contrasting life histories. Simulation of stream fish community assembly under flow-driven recruitment variation indicates that community structure will vary depending on how particular high-flow events affect species' relative abundances and ongoing density-dependent processes, including competition and predation. Results suggest that stream fish communities are likely to show alternate states rather than a single persistent equilibrium. However, community assembly will not be random but will depend on situation-specific interactions between density-independent and density-dependent processes.     

A method for measuring relative changes in guanosine 3'':5''-cyclic monophosphate in mouse neuroblastoma cells on muscarinic cholinergic stimulation.

A convenient, inexpensive assay was developed for measuring relative changes in cyclic GMP in whole mouse neuroblastoma cells (clone NIE 115) based on labelling the cellular GTP pool with [8(-3)H]guanine. The time course of cell labelling and the distribution of radioactivity among possible products were studied; GTP is the only major labelled species. Radioactive cyclic GMP produced from the radioactive GTP on cell stimulation is isolated by column chromatography nad its identity has been rigorously established by paper chromatography and ion-exchange chromatography. The assay was used to study the time course of the cyclic GMP changes that occur after stimulation of neuroblastoma cells with carbamoylcholine and the dependence of the cyclic GMP changes on the carbamoylcholine concentration. The assay gives results comparable with those obtained by using a radioimmunoassay for cyclic GMP and should be applicable to other whole-cell and tissue-slice systems.     

Equilibrium-dialysis studies of the interaction between cholic acid and 100000g-supernatant preparations from the rat liver.

1. The binding of cholic acid to 100000g supernatants from rat livers was investigated by equilibrium dialysis and gel-exculsion chromatography. 2. Supernatants were found to contain at least two classes of binding site for cholic acid. 3. These recptor molecules are probably proteins since incubation with proteolytic enzymes resulted in complete loss of cholic acid binding. 4. Supernatants were added to columns of Sephadex G-75, and two groups of fractions were shown to bind cholic acid. One of these contained low-affinity binding sites and the other contained both low- and high-affinity binding sites. 5. Feeding cholestyramine had no effect on cholic acid binding. 6. Increased cholic acid binding occurred after injection of phenobarbitone. There was an increase in the amount of the low-affinity component but no change in the high-affinity component. 7. The dissociation constants of the binding of cholic acid suggest that the binding proteins may be involved in bile acid transport.     

The effect of sodium channel activators on muscarinic receptors of neuroblastoma cells

Incubation of neuroblastoma NIE 115 cells with veratrine leads to an apparent reduction in the number of muscarinic acetylcholine receptors assayed by [3H]scopolamine methyl chloride binding. No true down-regulation of the receptors occurs but a component of veratrine with muscarinic receptor affinity, which is not veratridine, enters the intracellular water space during the incubation period and competes with [3H]scopolamine methyl chloride for the muscarinic binding sites in subsequent ligand binding assays unless it is carefully washed away. Treatment of cells with the agonist carbamoylcholine does, however, lead to a true downregulation of muscarinic receptors.     

First record of lily thrips, Liothrips vaneeckei Priesner, in Australia (Thysanoptera: Phlaeothripidae)

The first Australian record of the lily thrips, Liothrips vaneeckei Priesner, is reported from a bulb farm in Warragul South, Victoria. It is an occasional pest of Lilium bulbs, both in the field and in storage, particularly in the USA and several European countries, and is also infrequently found in considerable numbers on the corms of orchids.