Non-parallel changes in songbird migration timing are not explained by changes in stopover duration
Shifts in the timing of animal migration are widespread and well-documented; however, the mechanism underlying these changes is largely unknown. In this study, we test the hypothesis that systematic changes in stopover duration—the time that individuals spend resting and refueling at a site—are driving shifts in songbird migration timing. Specifically, we predicted that increases in stopover duration at our study site could generate increases in passage duration—the number of days that a study site is occupied by a particular species—by changing the temporal breadth of observations and vise versa. We analyzed an uninterrupted 46-year bird banding dataset from Massachusetts, USA using quantile regression, which allowed us to detect changes in early-and late-arriving birds, as well as changes in passage duration. We found that median spring migration had advanced by 1.04 days per decade; that these advances had strengthened over the last 13 years; and that early-and late-arriving birds were advancing in parallel, leading to negligible changes in the duration of spring passage at our site (+0.07 days per decade). In contrast, changes in fall migration were less consistent. Across species, we found that median fall migration had delayed by 0.80 days per decade, and that changes were stronger in late-arriving birds, leading to an average increase in passage duration of 0.45 days per decade. Trends in stopover duration, however, were weak and negative and, as a result, could not explain any changes in passage duration. We discuss, and provide some evidence, that changes in population age-structure, cryptic geographic variation, or shifts in resource availability are consistent with increases in fall passage duration. Moreover, we demonstrate the importance of evaluating changes across the entire phenological distribution, rather than just the mean, and stress this as an important consideration for future studies.
Dorian et al. (2020) Non-parallel changes in songbird migration timing are not explained by changes in stopover duration. PeerJ 8:e8975 https://doi.org/10.7717/peerj.8975
Recent advances in biochar application for water and wastewater treatment: a review
In the past decade, researchers have carried out a massive amount of research on the application of biochar for contaminants removal from aqueous solutions. As an emerging sorbent with great potential, biochar has shown significant advantages such as the broad sources of feedstocks, easy preparation process, and favorable surface and structural properties. This review provides an overview of recent advances in biochar application in water and wastewater treatment, including a brief discussion of the involved sorption mechanisms of contaminants removal, as well as the biochar modification methods. Furthermore, environmental concerns of biochar that need to be paid attention to and future research directions are put forward to promote the further application of biochar in practical water and wastewater treatment.
Environmental Contamination and Remediation
Wang et al. (2020) Recent advances in biochar application for water and wastewater treatment: a review. PeerJ 8:e9164 https://doi.org/10.7717/peerj.9164
The ability of oriental magpies (Pica serica) to solve baited multiple-string problems
Background Baited multiple-string problems are commonly used in avian laboratory studies to evaluate complex cognition. Several bird species possess the ability to use a string pull for obtaining food. Methods We initially tested and trained 11 magpies to determine whether the oriental magpie (Pica sericia) possesses the ability to solve baited multiple-string problems. Eight of the birds obtained the bait by pulling, and were selected for formal multiple-string tasks in the second stage. Second stage tests were divided into seven tasks based on string configurations. Results Only two magpies were able to solve two tasks: one solved the task of parallel strings, and the other solved the task of slanted strings with the bait farther from the middle point between the two strings and selected the short string in the task of long-short strings. When faced with more difficult tasks (i.e., the task of slanted strings with the bait closer to the middle point between the two strings, the task with two crossing strings, and the task of continuity and discontinuity), the birds initially observed the tasks and chose instead to adopt simpler strategies based on the proximity principle, side bias strategies and trial-and-error learning. Our results indicate that the oriental magpie had a partial understanding of the principle of multiple-string problems but adopted simpler strategies.
Wang et al. (2020) The ability of oriental magpies (Pica serica) to solve baited multiple-string problems. PeerJ 8:e9200 https://doi.org/10.7717/peerj.9200
The association of EGF rs2237051 variant, serum EGF levels and generalized aggressive periodontitis: a preliminary study
Background Epidermal growth factor (EGF) is a pro-inflammatory small peptide that stimulates cell growth, proliferation and differentiation through binding to its receptor. EGF rs2237051 and serum EGF levels have been demonstrated to be related with a variety of diseases, including several tumors and inflammatory diseases. Therefore, this study aims to investigate the association of the EGF rs2237051 variant and serum EGF levels in Chinese patients with generalized aggressive periodontitis (GAgP). Material and Methods A case-control study was conducted among 216 patients with GAgP and 138 healthy controls. The clinical parameters of plaque index, probing depth, attachment loss and bleeding index were recorded. The EGF rs2237051 polymorphism was genotyped using time-of-flight mass spectrometry, and serum EGF levels were determined. Logistic and linear regression models were used to investigate the association between the genotypes of EGF rs2237051, serum EGF levels and GAgP risk. Results The AA genotype of EGF rs2237051 showed higher risk for GAgP than the combined genotypes GG and AG (adjusted OR = 1.65, 95% CI [1.06–2.57]). Increased serum EGF levels were associated with GAgP (adjusted OR = 1.18, 95% CI [1.14–1.22]). Moreover, the serum EGF level for the AA genotype was significantly higher than that for the AG/GG genotypes in patients with GAgP (adjusted β = 4.70, 95% CI [2.09–7.31]). Conclusion We demonstrated that EGF rs2237051 variant and the increased level of serum EGF were associated with the risk of GAgP, the serum EGF was up-regulated in patients with GAgP. It was indicated that serum EGF might be a biomarker of GAgP and EGF rs2237051 may be related to the genetic background of GAgP.
Wang et al. (2020) The association of EGF rs2237051 variant, serum EGF levels and generalized aggressive periodontitis: a preliminary study. PeerJ 8:e9212 https://doi.org/10.7717/peerj.9212
The case for extended lifespan in cooperatively breeding mammals: a re-appraisal
Recent comparative studies have suggested that cooperative breeding is associated with increases in maximum lifespan among mammals, replicating a pattern also seen in birds and insects. In this study, we re-examine the case for increased lifespan in mammalian cooperative breeders by analysing a large dataset of maximum longevity records. We did not find any consistent, strong evidence that cooperative breeders have longer lifespans than other mammals after having controlled for variation in body mass, mode of life and data quality. The only possible exception to this general trend is found in the African mole-rats (the Bathyergid family), where all members are relatively long-lived, but where the social, cooperatively breeding species appear to be much longer-lived than the solitary species. However, solitary mole-rat species have rarely been kept in captivity or followed longitudinally in the wild and so it seems likely that their maximum lifespan has been underestimated when compared to the highly researched social species. Although few subterranean mammals have received much attention in a captive or wild setting, current data instead supports a causal role of subterranean living on lifespan extension in mammals.
Thorley (2020) The case for extended lifespan in cooperatively breeding mammals: a re-appraisal. PeerJ 8:e9214 https://doi.org/10.7717/peerj.9214
Plasma antioxidants and oxidative stress status in obese women: correlation with cardiopulmonary response
Introduction A high body fat coupled with low cardiopulmonary fitness and an increase in oxidative stress has been connoted as contributing factors in developing cardiovascular comorbidities. This study aimed to investigate the correlation between antioxidants and oxidative stress status with cardiopulmonary responses in women of different body mass index (BMI). Subjects and Methods Eighty female adults were recruited and divided into three groups; normal weight (n = 23), overweight (n = 28) and obese (n = 29), according to their BMI. Blood samples were obtained prior to cardiopulmonary exercise testing. Plasma samples were separated by centrifugation and analysed for enzymatic antioxidant activity including catalase, glutathione peroxidase and superoxide dismutase. Non-enzymatic antioxidant activities were assessed using 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging and ferric reducing ability of plasma (FRAP) assays. To evaluate the oxidative stress status of subjects, levels of reactive oxygen species and malondialdehyde, the by-product of lipid peroxidation, were measured. Cardiopulmonary responses were analysed using cardiopulmonary exercise testing (CPET) which involved 15 various parameters such as peak oxygen consumption, metabolic equivalents and respiratory exchange ratio. Results The obese group had significantly lower ABTS radical scavenging and FRAP activities than the normal weight group. A higher catalase activity was observed in the obese group than the normal weight group. Spearman’s correlation showed an inverse relationship between catalase and peak oxygen consumption, while partial correlation analysis showed inverse correlations between superoxide dismutase and respiratory frequency, ABTS activity and oxygen pulse, and between ABTS activity and cardiac output. Conclusion Our results demonstrate a lower cardiovascular fitness and antioxidant capacity in obese women; the higher catalase activity may be a compensatory mechanism. The negative correlations found between these two parameters may indicate the potential effect of antioxidants on the cardiopulmonary system and deserve further analysis in a larger population. Nevertheless, this study provides the basis for future studies to further explore the relationships between redox status and cardiopulmonary responses. This can potentially be used to predict future risk of developing diseases associated with oxidative stress, especially pulmonary and cardiovascular diseases.
Adenan et al. (2020) Plasma antioxidants and oxidative stress status in obese women: correlation with cardiopulmonary response. PeerJ 8:e9230 https://doi.org/10.7717/peerj.9230
Expression and protease characterization of a conserved protein YgjD in Vibrio harveyi
The glycopeptidase GCP and its homologue proteins are conserved and essential for survival of bacteria. The ygjD gene (Glycopeptidase homologue) was cloned from Vibrio harveyi strain SF-1. The gene consisted of 1,017 bp, which encodes a 338 amino acid polypeptide. The nucleotide sequence similarity of the ygjD gene with that of V. harveyi FDAARGOS 107 was 95%. The ygjD gene also showed similarities of 68%, 67% and 50% with those of Salmonella enterica, Escherichia coli and Bacillus cereus. The ygjD gene was expressed in E. coli BL21 (DE3) and the recombinant YgjD was purified by Ni2+ affinity chromatography column. The purified YgjD showed a specific 37 kDa band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and exhibited protease activities of 59,000 units/mg, 53,700 units/mg and 8,100 units/mg, respectively, on N-Acetyl-L-tyrosine ethyl ester monohydrate (ATEE), N-Benzoyl-L-tyrosine ethyl ester (BTEE) and N-Benzoyl-DL-arginine-4-nitroanilide hydrochloride (BAPNA) substrates. When the conserved amino acids of His111, Glu113 and His115 in the YgjD were replaced with alanine, respectively, the protease activities of the mutants were partly decreased. The two conserved His111 and His115 of YgjD were mutated and the protein lost the protease activity, which implied that the two amino acid played very important roles in maintaining its protease activity. The addition of the purified YgjD to the culture medium of V. harveyi strain SF-1 can effectively promote the bacteria growth. These results indicated that the protease activities may be involved in the survival of bacteria.
Zhang et al. (2020) Expression and protease characterization of a conserved protein YgjD in Vibrio harveyi. PeerJ 8:e9061 https://doi.org/10.7717/peerj.9061
The influence of surrounding land cover on wetland habitat conditions: a case study of inland wetlands in South Korea
Wetland ecosystems have been globally degraded and lost due to rapid urbanization and climate change. An assessment of national scale inventory, including wetland types and conditions, is urgently required to understand the big picture of endangered wetlands, such as where they are and how they look like. We analyzed the spatial patterns of each inland wetland type (brackish wetland was included) in South Korea and the relative importance of land cover categories on wetland conditions. The wetlands were grouped into four dominant types (riverine, lake, mountain, and human-made) according to their topography. Riverine wetlands constituted the largest area (71.3%). The relative ratio of wetlands in a well-conserved condition (i.e., “A” rank) was highest in riverine wetlands (23.8%), followed by mountain wetlands (22.1%). The higher proportion of grasslands was related to a better condition ranking, but the increasing bareland area had a negative impact on wetland conditions. We also found that wetlands located near wetland protected areas tend to be in a better condition compared to remote sites. Our results further support the importance of the condition of surrounding areas for wetland conservation.
Im et al. (2020) The influence of surrounding land cover on wetland habitat conditions: a case study of inland wetlands in South Korea. PeerJ 8:e9101 https://doi.org/10.7717/peerj.9101
Mitochondrial DNA variation in the Italian Heavy Draught Horse
Background In the last decades, Italy as well as other developed countries have registered a decrease in the population size of many local horse breeds. The continuous crossbreeding has determined the dilution of genetic heritage of several native breeds. The Italian Heavy Draught Horse (IHD) is the only autochthonous Italian coldblooded horse among these breeds; therefore, it represents a resource to be preserved. In 1927, the first generation of this breed was officially created by crossing different Heavy Draught horses with local mares and recorded in a Studbook. Methodology To provide the first comprehensive overview of the genetic diversity of Italian Heavy Draught horses from Central Italy, we produced and phylogenetically analysed 52 mitochondrial DNA (mtDNA) control-region sequences. Furthermore, we evaluated data available from GenBank (N = 568) to have a more complete scenario and to understand the relationships with other European Heavy Draught horse breeds. Results Among the IHD samples that were analysed, we identified ten of the 17 haplogroups described in modern horses. Most of these sequences fell into L, G, and M lineages, thus showing the overall mtDNA legacy of the ancestral mares that were probably used at the initial stages of breeding selections a long time ago. The high mitochondrial haplotype diversity (Hd = 0.969) found in our samples reflected the multiple maternal origins of the horses. Our results highlighted a considerable percentage of haplotypes shared especially with Bardigiano and Hungarian Heavy Draught breeds. Furthermore, both the presence of four unique haplotypes detected in our samples and their absence among all equine mitochondrial published data demonstrate a mitochondrial peculiarity that needs to be further investigated and preserved with careful breeding practices.
Lancioni et al. (2020) Mitochondrial DNA variation in the Italian Heavy Draught Horse. PeerJ 8:e8996 https://doi.org/10.7717/peerj.8996
A new genus of sinogaleaspids (Galeaspida, stem-Gnathostomata) from the Silurian Period in Jiangxi, China
Galeaspids are an endemic clade of jawless stem-gnathostomes known as ostracoderms. Their existence illuminates how specific characteristics developed in jawed vertebrates. Sinogaleaspids are of particular interest among the galeaspids but their monophyly is controversial because little is known about Sinogaleaspis xikengensis. Newly discovered sinogaleaspids from the Lower Silurian of Jiangxi, China provide a wealth of data and diagnostic features used to establish the new genus, Rumporostralis gen. nov., for Sinogaleaspis xikengensis. A morphological study showed that the sensory canal system of sinogaleaspids had mosaic features similar to those of three known galeaspids. There are 3–8 pairs of transverse canals in the Sinogaleaspidae, which suggests that the sensory canal system of galeaspid probably had a grid distribution with transverse canals arranged throughout the cephalic division. Phylogenetic analysis of Galeaspida supports the monophyly of the Sinogaleaspidae, consisting of Sinogaleaspis, Rumporostralis, and Anjiaspis. However, Shuyu and Meishanaspis form another monophyletic group, Shuyuidae fam. nov., which is outside all other eugaleaspidiforms. We propose a cladistically-based classification of Galeaspida based on our analysis.
Shan et al. (2020) A new genus of sinogaleaspids (Galeaspida, stem-Gnathostomata) from the Silurian Period in Jiangxi, China. PeerJ 8:e9008 https://doi.org/10.7717/peerj.9008