Non‐pollinating cheater wasps benefit from seasonally poor performance of the mutualistic pollinating wasps at the northern limit of the range of Ficus microcarpa

1. Species interactions in tightly bound ecological mutualisms often feature highly specialised species' roles in which competitive exclusion may preclude multi‐species coexistence. Among the 800 fig (Ficus) species, it was originally considered that each was pollinated by their own wasp (Agaonidae). However, recent investigations show that this ‘one‐to‐one’ rule often breaks down, as fig species regularly host multiple agaonids but in ways suggesting that competitive processes still mediate biodiversity outcomes. 2. A phenological survey was conducted of the fig–fig wasp pair, Ficus microcarpa and its associated pollinating wasp, alongside its sister species, the cheating wasp, in Xishuangbanna, China. 3. Reproductive output underwent extreme seasonal variation. Seed and pollinator production fell markedly during cooler, drier months, although high levels of fig production continued. However, this resource was predominantly utilised by the cheater species, which offers no pollination services. Pollinators and cheaters rarely co‐occur, suggesting that temporal coexistence is constrained by competition for access to figs. 4. The overall findings indicate periodic rearrangements of mutualism dynamics, probably resulting from a strongly seasonal environment. Sympatric co‐occurrence may result from a window of opportunity for a functionally divergent agaonid, potentially due to constraints on the main pollinator in adapting to variable year‐round conditions that prevent competitive exclusion.     

Development and Validation of a UPLC-MS/MS Method to Monitor Cephapirin Excretion in Dairy Cows following Intramammary Infusion

Cephapirin, a cephalosporin antibiotic, is used by the majority of dairy farms in the US. Fecal and urinary excretion of cephapirin could introduce this compound into the environment when manure is land applied as fertilizer, and may cause development of bacterial resistance to antibiotics critical for human health. The environmental loading of cephapirin by the livestock industry remains un-assessed, largely due to a lack of appropriate analytical methods. Therefore, this study aimed to develop and validate a cephapirin quantification method to capture the temporal pattern of cephapirin excretion in dairy cows following intramammary infusion. The method includes an extraction with phosphate buffer and methanol, solid-phase extraction (SPE) clean-up, and quantification using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The LOQ values of the developed method were 4.02 µg kg⁻¹ and 0.96 µg L⁻¹ for feces and urine, respectively. This robust method recovered >60% and >80% cephapirin from spiked blank fecal and urine samples, respectively, with acceptable intra- and inter-day variation (<10%). Using this method, we detected trace amounts (µg kg⁻¹) of cephapirin in dairy cow feces, and cephapirin in urine was detected at very high concentrations (133 to 480 µg L⁻¹). Cephapirin was primarily excreted via urine and its urinary excretion was influenced by day (P = 0.03). Peak excretion (2.69 mg) was on day 1 following intramammary infusion and decreased sharply thereafter (0.19, 0.19, 0.08, and 0.17 mg on day 2, 3, 4, and 5, respectively) reflecting a quadratic pattern of excretion (Quadratic: P = 0.03). The described method for quantification of cephapirin in bovine feces and urine is sensitive, accurate, and robust and allowed to monitor the pattern of cephapirin excretion in dairy cows. This data will help develop manure segregation and treatment methods to minimize the risk of antibiotic loading to the environment from dairy farms.     

Mechanism of endotoxin-induced reduction in the number of beta-adrenergic receptors in dog livers: role of phospholipase A

The role of phospholipase A on the endotoxin-induced reduction in the number of beta-adrenergic receptors in dog liver plasma membranes was investigated. The results show that digestion of control liver plasma membranes with exogenous phospholipase A2 (0.2 unit/200 micrograms protein) decreased the specific binding of (-)-[3H]dihydroalprenolol by 37.3% (P less than 0.01) and reduced the number of receptor sites by 31.7% (P less than 0.05). These decreases in the specific binding and the number of beta-adrenergic receptors were completely reversible by the addition of phosphatidylcholine (0.2 mM). Endotoxin administration (2 hr postendotoxin) decreased the specific binding by 36% (P less than 0.05) and reduced the number of beta-adrenergic receptors by 33% (P less than 0.05), and these decreases were completely reversible by the addition of 0.2 mM phosphatidylcholine. Digestion of control liver membranes with exogenous phospholipase A2 decreased phosphatidylcholine and phosphatidylethanolamine levels by 50.6 and 51.2%, respectively, but increased lysophosphatidylcholine and lysophosphatidylethanolamine levels by 12- and 8.4-fold, respectively. Endotoxin administration decreased phosphatidylcholine and phosphatidylethanolamine contents by 21.4 and 23.8%, respectively, but increased lysophosphatidylcholine and lysophosphatidylethanolamine contents by 2.1- and 1.4-fold, respectively. In addition, endotoxin administration increased endogenous phospholipase A activity by 73.5%. Based on these results, it is suggested that the decreases in the specific binding and the number of beta-adrenergic receptors in dog livers during endotoxic shock are a result of phospholipase A activation.     

Relationship of physical fitness, hormone replacement therapy, and hemostatic risk factors in postmenopausal women.

This cross-sectional study evaluated the relationship of physical fitness, hormone replacement therapy (HRT), and hemostatic profiles at rest and after an acute bout of maximal exercise in 48 healthy postmenopausal women. Subjects were categorized by fitness and HRT user status into four groups: unfit nonusers, fit nonusers, unfit users, and fit users. Fibrinolytic variables tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) activity, and antigen and prothrombin fragment 1 + 2, a molecular marker of in vivo thrombin generation, were measured before and after maximal exercise. Fibrinogen was also measured at rest. Higher tPA and lower PAI-1 activities (P <0.05) were seen in HRT users and fit groups. tPA and PAI-1 antigens were lower in HRT and fit groups (P <0.05) but not after correction for body mass index. Prothrombin fragment 1 + 2 was lower in the fit groups regardless of HRT status (P <0.05). Fibrinogen was similar in all groups. Favorable hemostatic profiles were observed in physically fit compared with unfit women, especially in HRT nonusers. Thus fitness is more strongly related to these hemostatic risk factors compared with HRT since HRT did not affect these hemostatic variables in fit postmenopausal women.     

Site-Specific Structural Variations Accompanying Tubular Assembly of the HIV-1 Capsid Protein

The 231-residue capsid (CA) protein of human immunodeficiency virus type 1 (HIV-1) spontaneously self-assembles into tubes with a hexagonal lattice that is believed to mimic the surface lattice of conical capsid cores within intact virions. We report the results of solid-state nuclear magnetic resonance (NMR) measurements on HIV-1 CA tubes that provide new information regarding changes in molecular structure that accompany CA self-assembly, local dynamics within CA tubes, and possible mechanisms for the generation of lattice curvature. This information is contained in site-specific assignments of signals in two- and three-dimensional solid-state NMR spectra, conformation-dependent ¹⁵N and ¹³C NMR chemical shifts, detection of highly dynamic residues under solution NMR conditions, measurements of local variations in transverse spin relaxation rates of amide ¹H nuclei, and quantitative measurements of site-specific ¹⁵N–¹⁵N dipole–dipole couplings. Our data show that most of the CA sequence is conformationally ordered and relatively rigid in tubular assemblies and that structures of the N-terminal domain (NTD) and the C-terminal domain (CTD) observed in solution are largely retained. However, specific segments, including the N-terminal β-hairpin, the cyclophilin A binding loop, the inter-domain linker, segments involved in intermolecular NTD–CTD interactions, and the C-terminal tail, have substantial static or dynamical disorder in tubular assemblies. Other segments, including the 3₁₀-helical segment in CTD, undergo clear conformational changes. Structural variations associated with curvature of the CA lattice appear to be localized in the inter-domain linker and intermolecular NTD–CTD interface, while structural variations within NTD hexamers, around local 3-fold symmetry axes, and in CTD–CTD dimerization interfaces are less significant.     

Nonthermal Plasma‐Induced Degradation of Morin and Enhancement of Biological Activities

In the present study, non‐thermal dielectric barrier discharge (DBD) plasma of induced structural changes of morin resulted in the isolation of one previously undescribed benzofuranone derivative, along with two known compounds. The chemical structures of these degradation products were elucidated by UV, NMR and FAB‐MS spectroscopic analyses. The isolated three compounds showed potent antioxidative activities in two different tests, with IC₅₀ values in the range of 12.9–41.8 μm in the 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS⁺) radical scavenging activity, 19.0–71.9 μm for hydroxyl radical scavenging activity test. Furthermore, the new methoxylated benzofuranone exhibited enhancement of inhibitory effects against pancreatic lipase with an IC₅₀ value of 90.7±1.6 μm , when compared to the parent morin. These results suggested that the degradation products isolated from plasma exposed morin might be beneficial for prevention of obesity and related diseases.     

A divergent lineage among Octopus minor (Sasaki, 1920) populations in the Northwest Pacific supported by DNA barcoding

Octopus minor (Sasaki, 1920) is an important economic fishery resource in China. In order to explore the stock information and the phylogeographic status of O. minor, mitochondrial DNA cytochrome c oxidase subunit I (COI, 565?bp) and 16S rRNA (493?bp) genes were amplified from 11 different sampling locations. Genetic diversity evaluated by haplotypic and nucleotidic diversity implied high diversity in Lianjiang, and relatively low diversity in Rongcheng, which suggests that effective measures to protect the O. minor resource in this area are urgently required. Private haplotypes and remarkable higher pairwise Φ_ST in Yilan are responsible for the deep genetic divergence between Yilan and the 10 other populations. Haplotypes networks and two clusters’ topological structure also support the distinct subgroups (lineages A and lineages B), which apparently possess smaller genetic variation than mean interspecies distance. Taiwan island and its strait may act as a natural barrier that restricts the gene flow from the mainland. Deep genetic divergence between mainland and Taiwanese east coasts suggests different genetic stock, indicating that different management strategies are required.     

Spectral composition of shade light in coastal-zone oak forests in SE Bulgaria,and relationships with leaf area index: a first overview

Major knowledge gaps exist with respect to light-quality regimes in the coastal-zone Strandzha Quercus frainetto (Q.f.) forest region adjoining the southern Bulgarian Black Sea. This paper presents preliminary results that help narrow these gaps. In conjunction with leaf area index (LAI) field campaigns we undertook measurements with an array of 7 broad-band (ca 40 nm) sensors covering the range 0.40–0.94 μm, plus 1 sensor for UVB (0.297 μm peak) and 1 for photosynthetically active radiation (PAR). Measurements focused on inside-forest shade conditions at sites 0 to ca 15 km from the Black Sea and at altitudes up to ca 120 m above sea level. Some of the sites were also studied using a high-resolution spectroradiometer. A sequential measuring strategy was necessary. This involves potentially large uncertainties, here addressed through estimations of the variability around the sinusoidal course of daylight. Light-quality regimes were found to be in general support of earlier studies of deciduous forests. Our data from the broad-band sensors and from the spectroradiometer are mutually supportive. They indicate a stronger red-shift below Q.f. canopies than below canopies in enclaves dominated by Fagus orientalis and Pinus sylvestris. Transmission in the range 0.50–0.55 μm increases beneath the three types of canopies, most pronounced in the Q.f. case. Analysis of relationships between the inside-forest to open-field irradiance ratio and LAI supports the use of Beer’s Law. We found a fairly strong relationship between the red (0.66 μm) to far-red (0.73 μm) irradiance ratios (R/FR) and LAI for the Q.f. forest. In quantitative terms, the result is new for this Q.f. region, and suggests further research to explore whether a two-sensor approach (0.66 and 0.73 μm) might offer possibilities for further low-cost mapping of the spatio-temporal patterns of R/FR and LAI in Strandzha. Such mapping would assist in further studies of the region’s forest biogeochemistry and vitality.