The effectiveness of flower strips and hedgerows on pest control,pollination services and crop yield: a quantitative synthesis

Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control (18 studies) and pollination services (17 studies) in adjacent crops in North America, Europe and New Zealand. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimise floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future.     

Improved productivity of <Emphasis Type="Italic">β</Emphasis>-fructofuranosidase by a derepressed mutant of <Emphasis Type="Italic">Aspergillus niger</Emphasis> from conventional and non-conventional substrates

Summary Wild-type cultures of Aspergillus niger produced a basal level of β-fructofuranosidase on glucose of 1 IU l⁻¹ h⁻¹. In contrast, a catabolite-derepressed mutant strain of the same organism produced a markedly higher level (25 IU l⁻¹ h⁻¹) of this enzyme when grown on the same carbon source. Wheat bran induced both the wild type (252 IU l⁻¹ h⁻¹) and the mutant strain (516 IU l⁻¹ h⁻¹) to produce 252- to 516-fold higher levels of this enzyme than was observed with the wild-type grown on glucose and was the best carbon source. When corn steep liquor served as a nitrogen source, the wild-type organism showed a higher activity of enzyme on monosaccharides and disaccharides comparable to that produced by corncobs in the basal medium and that mutant was a potentially improved (> 2-fold) organism for the production of β-fructofuranosidase on all carbon sources. Enhanced substrate consumption and product formation kinetic parameters suggest that the mutant organism may be exploited for bulk production of this useful enzyme.     

Neuroprotective role of hydralazine in rat spinal cord injury‐attenuation of acrolein‐mediated damage

Acrolein, an α,β‐unsaturated aldehyde and a reactive product of lipid peroxidation, has been suggested as a key factor in neural post‐traumatic secondary injury in spinal cord injury (SCI), mainly based on in vitro and ex vivo evidence. Here, we demonstrate an increase of acrolein up to 300%; the elevation lasted at least 2 weeks in a rat SCI model. More importantly, hydralazine, a known acrolein scavenger can provide neuroprotection when applied systemically. Besides effectively reducing acrolein, hydralazine treatment also resulted in significant amelioration of tissue damage, motor deficits, and neuropathic pain. This effect was further supported by demonstrating the ability of hydralazine to reach spinal cord tissue at a therapeutic level following intraperitoneal application. This suggests that hydralazine is an effective neuroprotective agent not only in vitro, but in a live animal model of SCI as well. Finally, the role of acrolein in SCI was further validated by the fact that acrolein injection into the spinal cord caused significant SCI‐like tissue damage and motor deficits. Taken together, available evidence strongly suggests a critical causal role of acrolein in the pathogenesis of spinal cord trauma. Since acrolein has been linked to a variety of illness and conditions, we believe that acrolein‐scavenging measures have the potential to be expanded significantly ensuring a broad impact on human health.

     

Human DDX6 effects miRNA-mediated gene silencing via direct binding to CNOT1

MicroRNAs (miRNAs) play critical roles in a variety of biological processes through widespread effects on protein synthesis. Upon association with the miRNA-induced silencing complex (miRISC), miRNAs repress target mRNA translation and accelerate mRNA decay. Degradation of the mRNA is initiated by shortening of the poly(A) tail by the CCR4–NOT deadenylase complex followed by the removal of the 5′ cap structure and exonucleolytic decay of the mRNA. Here, we report a direct interaction between the large scaffolding subunit of CCR4–NOT, CNOT1, with the translational repressor and decapping activator protein, DDX6. DDX6 binds to a conserved CNOT1 subdomain in a manner resembling the interaction of the translation initiation factor eIF4A with eIF4G. Importantly, mutations that disrupt the DDX6–CNOT1 interaction impair miRISC-mediated gene silencing in human cells. Thus, CNOT1 facilitates recruitment of DDX6 to miRNA-targeted mRNAs, placing DDX6 as a downstream effector in the miRNA silencing pathway.     

Protective effects of L-pGlu-(2-propyl)-L-His-L-ProNH2, a newer thyrotropin releasing hormone analog in in vitro and in vivo models of cerebral ischemia

In the present study, the newly synthesized TRH analog (l-pGlu-(2-propyl)-l-His-l-ProNH₂; NP-647) was evaluated for its effects in in vitro (oxygen glucose deprivation (OGD)-, glutamate- and H₂O₂-induced injury in PC-12 cells) and in vivo (transient global ischemia) models of cerebral ischemic injury. PC-12 cells were subjected to oxygen and glucose deprivation for 6 h. Exposure of NP-647 was given before and during OGD. In glutamate and H₂O₂ induced injury, exposure of NP-647 was given 1, 6 and 24 h prior to exposure of glutamate and H₂O₂ exposure. NP-647, per se found to be non-toxic in 1-100 μM concentrations. NP-647 showed protection against OGD at the 1 and 10 μM. The concentration-dependent protection was observed in H₂O₂- and glutamate-induced cellular injury. In in vivo studies, NP-647 treatment showed protection of hippocampal (CA1) neuronal damage in transient global ischemia in mice and subsequent improvement in memory retention was observed using passive avoidance retention test. Moreover, administration of NP-647 resulted in decrease in inflammatory cytokines TNF-α and IL-6 as well as lipid peroxidation. These results suggest potential of NP-647 in the treatment of cerebral ischemia and its neuroprotective effect may be attributed to reduction of excitotoxicity, oxidative stress and inflammation.     

Deciphering the binding of carbendazim (fungicide) with human serum albumin: A multi-spectroscopic and molecular modelling studies

Carbendazim is a benzimidazole fungicide used to control the fungal invasion. However, its exposure might lead to potential health problems. The present study evaluates the interaction of carbendazim (CAR) with human serum albumin (HSA) which is an important drug carrier protein and plays a very crucial role in the transportation of small molecules. A number of biophysical techniques were employed to investigate the binding of CAR with HSA. The increased UV-absorption of HSA on titrating with CAR suggests the formation of HSA–CAR complex and it could be due to the exposure of aromatic residues. The fluorescence study confirmed that CAR quenches the fluorescence of HSA and showed the static mode of quenching. CAR (50 µM) quenches around 56.14% of the HSA fluorescence. The quenching constant, binding constant, number of binding site and free energy change was calculated by fluorescence quenching experiment. Competitive displacement assay showed Sudlow’s site I as the primary binding site of CAR on HSA. The synchronous fluorescence study revealed the perturbation in the microenvironment around tyrosine and tryptophan residues upon binding of CAR to HSA. The circular dichroism results suggested that the binding of CAR to HSA altered its secondary structure. Molecular docking experiment demonstrated the binding of CAR to Sudlow’s site I of HSA. Docking studies suggested that the hydrogen bonding, van der Waals and pi-alkyl are playing role in the interaction of CAR with HSA. The study confirmed the conformational changes within HSA upon binding of CAR.     

Membrane proteomic signatures of karyotypically normal and abnormal human embryonic stem cell lines and derivatives

Cultured human embryonic stem cells (hESCs) and derived derivatives contain heterogeneous cell populations with varying degrees of differentiation and karyotypic stability. The inability to isolate homogenous population presents a challenge toward cell-based applications and therapies. A proteomics approach was utilized to discover novel membrane proteins able to distinguish between the hESC lines BG01, WA09, and abBG02 (trisomy 12, 14, 17 and an extra copy of the X chromosome), along with WA09-derived human neural progenitor (hNP) cells. Membrane protein signatures were developed using sucrose-gradient isolation, 1-D gel electrophoresis followed by in-gel digestion and analysis by reverse phase chromatography coupled to ion trap-FT-ICR. At a ≤1.0% false discovery rate, 1918 proteins were identified; 775 were annotated as membrane proteins and 720 predicted to contain transmembrane spanning regions. Flow cytometry was used to validate cell surface expression of selected proteins. Junctional adhesion molecule 1 expression was shared by BG01, BG02 and abBG02 hESC lines. Dysferlin expression was specific to the WA09 hESC line and not the derived neural or mesenchymal progenitors. Ciliary neurotrophic factor receptor distinguished WA09-derived human neural progenitor cells from the parent hESC population, and WA09-derived mesenchymal progenitor cells. This study expands the current membrane protein data set for hESCs.     

The GacA global regulator of Vibrio fischeri is required for normal host tissue responses that limit subsequent bacterial colonization

Harmful and beneficial bacterium-host interactions induce similar host-tissue changes that lead to contrasting outcomes of association. A life-long association between Vibrio fischeri and the light organ of its host Euprymna scolopes begins when the squid collects bacteria from the surrounding seawater using mucus secreted from ciliated epithelial appendages. Following colonization, the bacterium causes changes in host tissue including cessation of mucus shedding, and apoptosis and regression of the appendages that may limit additional bacterial interactions. We evaluated whether delivery of morphogenic signals is influenced by GacA, a virulence regulator in pathogens, which also influences squid-colonization by V. fischeri. Low-level colonization by a GacA mutant led to regression of the ciliated appendages. However, the GacA mutant did not induce cessation of mucus shedding, nor did it trigger apoptosis in the appendages, a phenotype that normally correlates with their regression. Because apoptosis is triggered by lipopolysaccharide, we examined the GacA mutant and determined that it had an altered lipopolysaccharide profile as well as an increased sensitivity to detergents. GacA-mutant-colonized animals were highly susceptible to invasion by secondary colonizers, suggesting that the GacA mutant's inability to signal the full programme of light-organ responses permitted the prolonged recruitment of additional symbionts.     

Tissue strain amplification at the osteocyte lacuna: a microstructural finite element analysis

A parametric finite element model of an osteocyte lacuna was developed to predict the microstructural response of the lacuna to imposed macroscopic strains. The model is composed of an osteocyte lacuna, a region of perilacunar tissue, canaliculi, and the surrounding bone tissue. A total of 45 different simulations were modeled with varying canalicular diameters, perilacunar tissue material moduli, and perilacunar tissue thicknesses. Maximum strain increased with a decrease in perilacunar tissue modulus and decreased with an increase in perilacunar tissue modulus, regardless of the thickness of the perilacunar region. An increase in the predicted maximum strain was observed with an increase in canalicular diameter from 0.362 to 0.421 microm. In response to the macroscopic application of strain, canalicular diameters increased 0.8% to over 1.0% depending on the perilacunar tissue modulus. Strain magnification factors of over 3 were predicted. However, varying the size of the perilacunar tissue region had no effect on the predicted perilacunar tissue strain. These results indicate that the application of average macroscopic strains similar to strain levels measured in vivo can result in significantly greater perilacunar tissue strains and canaliculi deformations. A decrease in the perilacunar tissue modulus amplifies the perilacunar tissue strain and canaliculi deformation while an increase in the local perilacunar tissue modulus attenuates this effect.     

Change in climatically suitable breeding distributions reduces hybridization potential between Vermivora warblers

Aim

Climate change is affecting the distribution of species and subsequent biotic interactions, including hybridization potential. The imperiled Golden-winged Warbler (GWWA) competes and hybridizes with the Blue-winged Warbler (BWWA), which may threaten the persistence of GWWA due to introgression. We examined how climate change is likely to alter the breeding distributions and potential for hybridization between GWWA and BWWA.

Location

North America.

Methods

We used GWWA and BWWA occurrence data to model climatically suitable conditions under historical and future climate scenarios. Models were parameterized with 13 bioclimatic variables and 3 topographic variables. Using ensemble modeling, we estimated historical and modern distributions, as well as a projected distribution under six future climate scenarios. We quantified breeding distribution area, the position of and amount of overlap between GWWA and BWWA distributions under each climate scenario. We summarized the top explanatory variables in our model to predict environmental parameters of the distributions under future climate scenarios relative to historical climate.

Results

GWWA and BWWA distributions are projected to substantially change under future climate scenarios. GWWA are projected to undergo the greatest change; the area of climatically suitable breeding season conditions is expected to shift north to northwest; and range contraction is predicted in five out of six future climate scenarios. Climatically suitable conditions for BWWA decreased in four of the six future climate scenarios, while the distribution is projected to shift east. A reduction in overlapping distributions for GWWA and BWWA is projected under all six future climate scenarios.

Main Conclusions

Climate change is expected to substantially alter the area of climatically suitable conditions for GWWA and BWWA, with the southern portion of the current breeding ranges likely to become climatically unsuitable. However, interactions between BWWA and GWWA are expected to decline with the decrease in overlapping habitat, which may reduce the risk of genetic introgression.