Partitioning the biodiversity effects on productivity into density and size components

Plant density and size — two factors that represent plant survival and growth — are key determinants of yield but have rarely been analysed explicitly in the context of biodiversity–productivity relationships. Here, we derive equations to partition the net, complementarity and selection effects of biodiversity into additive components that reflect diversity-induced changes in plant density and size. Applications of the new method to empirical datasets reveal contrasting ways in which plant density and size regulate yield in species mixtures. In an annual plant diversity experiment, overyielding is largely explained by selection effects associated with increased size of highly productive plant species. In a tree diversity experiment, the cause of overyielding shifts from enhanced growth in tree size to reduced mortality by complementary use of canopy space during stand development. These results highlight the capability of the new method to resolve crucial, yet understudied, demographic links between biodiversity and productivity.     

Human appropriation of net primary production as driver of change in landscape-scale vertebrate richness

Aim

Land use is the most pervasive driver of biodiversity loss. Predicting its impact on species richness (SR) is often based on indicators of habitat loss. However, the degradation of habitats, especially through land-use intensification, also affects species. Here, we evaluate whether an integrative metric of land-use intensity, the human appropriation of net primary production, is correlated with the decline of SR in used landscapes across the globe.

Location

Global.

Time period

Present.

Major taxa studied

Birds, mammals and amphibians.

Methods

Based on species range maps (spatial resolution: 20 km × 20 km) and an area-of-habitat approach, we calibrated a “species–energy model” by correlating the SR of three groups of vertebrates with net primary production and biogeographical covariables in “wilderness” areas (i.e., those where available energy is assumed to be still at pristine levels). We used this model to project the difference between pristine SR and the SR corresponding to the energy remaining in used landscapes (i.e., SR loss expected owing to human energy extraction outside wilderness areas). We validated the projected species loss by comparison with the realized and impending loss reconstructed from habitat conversion and documented by national Red Lists.

Results

Species–energy models largely explained landscape-scale variation of mapped SR in wilderness areas (adjusted R²-values: 0.79–0.93). Model-based projections of SR loss were lower, on average, than reconstructed and documented ones, but the spatial patterns were correlated significantly, with stronger correlation in mammals (Pearson's r = 0.68) than in amphibians (r = 0.60) and birds (r = 0.57).

Main conclusions

Our results suggest that the human appropriation of net primary production is a useful indicator of heterotrophic species loss in used landscapes, hence we recommend its inclusion in models based on species–area relationships to improve predictions of land-use-driven biodiversity loss.     

Relationships between mutans streptococci and perceived treatment need of primary root-caries lesions.

A total of 447 primary root-caries lesions from 169 dental patients was studied to determine the relationships between mutans streptococci and the perceived treatment need of primary root-caries lesions. Samples of this altered dentine for microbiological culture were obtained. Lesions were classified into 5 treatment categories; soft and restore, leathery and restore, leathery and debride of caries, leathery and treat chemotherapeutically, and hard, to receive no treatment. The total numbers of mutans streptococci decreased significantly with decreased treatment need. The percentage of mutans streptococci from lesions requiring no treatment was significantly less than from lesions requiring treatment. The frequency of isolation of mutans streptococci was significantly greater from lesions requiring more treatment. Significantly more lesions containing > 10² mutans streptococci were distributed in the groups with a greater perceived treatment need or with larger dimensions occlusogingivally and/or mesio-distally or bucco-lingually or with a closer proximity to the gingival margin.     

The challenge of estimating kelp production in a turbid marine environment

Coastal kelp forests produce substantial marine carbon due to high annual net primary production (NPP) rates, but upscaling of NPP estimates over time and space remains difficult. We investigated the impact of variable underwater photosynthetically active radiation (PAR) and photosynthetic parameters on photosynthetic oxygen production of Laminaria hyperborea, the dominant NE-Atlantic kelp species, throughout summer 2014. Collection depth of kelp had no effect on chlorophyll a content, pointing to a high photoacclimation potential of L. hyperborea towards incident light. However, chlorophyll a and photosynthesis versus irradiance parameters differed significantly along the blade gradient when normalized to fresh mass, potentially introducing large uncertainties in NPP upscaling to whole thalli. Therefore, we recommend a normalization to kelp tissue area, which is stable over the blade gradient. Continuous PAR measurements revealed a highly variable underwater light climate at our study site (Helgoland, North Sea) in summer 2014, reflected by PAR attenuation coefficients (K_d) between 0.28 and 0.87 m⁻¹. Our data highlight the importance of continuous underwater light measurements or representative average values using a weighted K_d to account for large PAR variability in NPP calculations. Strong winds in August increased turbidity, resulting in a negative carbon balance at depths >3–4 m over several weeks, considerably impacting kelp productivity. Estimated daily summer NPP over all four depths was 1.48 ± 0.97 g C · m⁻² seafloor · d⁻¹ for the Helgolandic kelp forest, which is in the range of other kelp forests along European coastlines.     

PDGF-AA activates AKT and ERK signaling for testicular interstitial Leydig cell growth via primary cilia

Testes control the development of male reproductive system. The testicular interstitial Leydig cells (Leydig cells) synthesize testosterone for promoting spermatogenesis and secondary sexual characteristics. Type A platelet-derived growth factor (PDGF-AA) is one of the most important growth factors in regulating Leydig cell growth and function. Knockout of PDGF-AA or its congenital receptor PDGFR-α leads to poor testicular development caused by reducing Leydig cell numbers, supporting PDGF-AA/PDGFR-α signaling regulates Leydig cell development. Primary cilium is a cellular antenna that functions as an integrative platform to transduce extracellular signaling for proper development and differentiation. Several receptors including PDGFR-α are observed on primary cilia for initiating signaling cascades in distinct cell types. Here we showed that PDGF-AA/PDGFR-α signaling promoted Leydig cells growth, migration, and invasion via primary cilia. Upon PDGF-AA treatment, AKT and ERK signaling were activated to regulate these cellular events. Interestingly, active AKT and ERK were detected around the base of primary cilia. Depletion of ciliary genes (IFT88 and CEP164) alleviated PDGF-AA-activated AKT and ERK, thus reducing Leydig cell growth, migration, and invasion. Thus, our study not only reveals the function of PDGF-AA/PDGFR-α signaling in maintaining testicular physiology but also uncovers the role of primary cilium and downstream signaling in regulating Leydig cell development.     

Proteomic fingerprinting enables quantitative biodiversity assessments of species and ontogenetic stages in Calanus congeners (Copepoda,Crustacea) from the Arctic Ocean

Species identification is pivotal in biodiversity assessments and proteomic fingerprinting by MALDI-TOF mass spectrometry has already been shown to reliably identify calanoid copepods to species level. However, MALDI-TOF data may contain more information beyond mere species identification. In this study, we investigated different ontogenetic stages (copepodids C1–C6 females) of three co-occurring Calanus species from the Arctic Fram Strait, which cannot be identified to species level based on morphological characters alone. Differentiation of the three species based on mass spectrometry data was without any error. In addition, a clear stage-specific signal was detected in all species, supported by clustering approaches as well as machine learning using Random Forest. More complex mass spectra in later ontogenetic stages as well as relative intensities of certain mass peaks were found as the main drivers of stage distinction in these species. Through a dilution series, we were able to show that this did not result from the higher amount of biomass that was used in tissue processing of the larger stages. Finally, the data were tested in a simulation for application in a real biodiversity assessment by using Random Forest for stage classification of specimens absent from the training data. This resulted in a successful stage-identification rate of almost 90%, making proteomic fingerprinting a promising tool to investigate polewards shifts of Atlantic Calanus species and, in general, to assess stage compositions in biodiversity assessments of Calanoida, which can be notoriously difficult using conventional identification methods.     

高频重复经颅磁刺激联合Brunnstrom分期训练对脑卒中恢复期患者康复效果的影响

摘要 目的：探讨高频重复经颅磁刺激（rTMS）联合Brunnstrom分期训练对脑卒中恢复期患者康复效果的影响。方法：根据随机数字表法将新疆医科大学第一附属医院2020年1月~2022年2月期间收治的脑卒中恢复期患者80例分为对照组（40例,Brunnstrom分期训练）和研究组（40例,高频rTMS联合Brunnstrom分期训练）。对比两组疗效、美国国立卫生研究院卒中量表（NIHSS）评分、功能独立性量表（FIM）评分、生活质量评分、血清神经因子指标[髓鞘碱性蛋白（MBP）、神经元特异性烯醇化酶（NSE）、神经生长因子-1（NGF-1）]。结果：研究组的临床总有效率（92.50%）明显高于对照组（70.00%）（P<0.05）。治疗4周后,研究组MBP、NSE低于对照组,NGF-1高于对照组（P<0.05）。与对照组比较,治疗4周后,研究组NIHSS评分降低,FIM评分升高（P<0.05）。治疗4周后,研究组心理/躯体/物质/社会功能评分较对照组高（P<0.05）。结论：高频rTMS联合Brunnstrom分期训练有助于提高脑卒中恢复期患者的康复效果,同时还可调节血清神经指标,提高生活质量。     

淋巴细胞及其亚群、NK细胞与儿童原发性免疫性血小板减少症复发的相关性研究

摘要 目的：为探讨淋巴细胞及其亚群、NK细胞与儿童原发性免疫性血小板减少症（ITP）复发的关系,评估其预测价值,为临床评估患者预后提供理论支持。方法：回顾性分析2017年12月-2021年12月于新疆医科大学第一附属医院儿科中心初发首诊为原发性免疫性血小板减少症的165例患儿,根据是否复发分为复发组与无复发组,评估ITP复发的影响因素,利用ROC曲线评估淋巴细胞计数绝对值对儿童ITP复发的预测价值,运用Kaplan-Meier法绘制与淋巴细胞计数绝对值相关的儿童ITP无复发生存曲线。结果：共纳入165名ITP患儿,复发率24.8%。淋巴细胞计数绝对值对儿童ITP无复发的ROC曲线下面积为0.704,95%CI为0.613-0.795（P＜0.05）,最佳截断值为3.21×10⁹/L。儿童ITP是否复发与年龄、淋巴细胞计数、出血评分、ESR有关,两组比较差异有统计学意义（P<0.05）。儿童ITP是否复发与CD3⁺CD19^-细胞计数、CD3⁺CD4⁺细胞计数、CD3⁺CD8⁺细胞计数、CD4⁺/CD8⁺细胞比例、NK细胞计数有关,两组比较差异有统计学意义（P<0.05）。结论：淋巴细胞计数绝对值可作为评估儿童ITP复发的预测指标,儿童ITP复发与初始T淋巴细胞亚群、NK细胞计数具有一定相关性。     

血清PGRN、SFRP1、CCL26与支气管哮喘急性发作期患者肺功能和气道炎症的相关性研究

摘要 目的：探讨支气管哮喘（BA）急性发作期患者血清颗粒蛋白前体（PGRN）、分泌型卷曲相关蛋白1（SFRP1）、C-C基序趋化因子配体26（CCL26）与肺功能和气道炎症的相关性。方法：选取2021年1月～2022年6月我院收治的118例BA急性发作期患者作为急性发作期组,根据病情分级将BA急性发作期患者分为轻度亚组55例、中度亚组43例、重度亚组20例,另选取同期77例BA临床控制期患者（临床控制期组）和60例体检健康志愿者（对照组）分别作为对照。采用Pearson相关性分析BA急性发作期患者血清PGRN、SFRP1、CCL26水平与肺功能和气道炎症指标的相关性。结果：对照组、临床控制期组、急性发作期组血清PGRN水平和第1秒用力呼气容积占预计值百分比（FEV₁%pred）、峰值呼气流速（PEF）依次降低,SFRP1、CCL26水平和呼出气一氧化氮（FeNO）、外周血嗜酸性粒细胞（EOS）计数依次升高（P＜0.05）。轻度亚组、中度亚组、重度亚组血清PGRN水平和FEV₁%pred、PEF依次降低,SFRP1、CCL26水平和FeNO、外周血EOS计数依次升高（P＜0.05）。Pearson相关性分析显示,BA急性发作期患者血清PGRN水平与FEV₁%pred、PEF呈正相关,与FeNO、外周血EOS计数呈负相关（P＜0.05）,SFRP1、CCL26与FEV₁%pred、PEF呈负相关,与FeNO、外周血EOS计数呈正相关（P＜0.05）。结论：BA急性发作期患者血清PGRN水平降低,SFRP1、CCL26水平升高,与病情严重程度、肺功能和气道炎症有关,可能成为BA急性发作期患者新的治疗靶点。