Gram-negative bacterial 3-hydroxy fatty acids (3-OH-FAs) 20 biomarkers are widespread in a variety of environments including both marine 21 and terrestrial sediments (including speleothems). In this study we analysed 22 the hydroxylated membrane lipids of 26 soil samples from an altitudinal 23 transect of Shennongjia Mountain (Mt.) in central China to study the 24 environmental factors controlling the relative distribution of 3-OH-FAs. Our 25 results show that both the ratio of the summed iso and anteiso to the total 26 amount of normal 3-OH-FAs (RIAN), and the ratio of summed iso and anteiso 27 to the total amount of all 3-OH-FAs (Branched Index) were primarily related to 28 the pH of soil (R 2 = 0.70 and 0.70, respectively). Additionally, the anteiso to 29 normal 3-hydroxy fatty acids ratio of the C15 and C17 homologues (RAN15 and 30 RAN17) shows a significant negative correlation with mean annual air 31 temperature (MAAT) (R 2 =0.51 and 0.48, respectively). When comparing the 3-32 OH-FA based indices with established glycerol dialkyl glycerol tetraether 33 (GDGT) based indices from the same soil samples, the RIAN and Branched 34 Index show strong linear correlations with the cyclisation ratio of branched 35 tetraethers (CBT) (R 2 = 0.77 and 0.74, respectively), and the RAN15 and RAN17 36 show negative correlations with the MBT/CBT-MAAT (MBT, methylation index 37 of branched tetraethers) (R 2 = 0.61 and 0.36, respectively). Our new field-based 38 correlations demonstrate the physiological response of Gram-negative bacterial 39 cell membranes to the external environment and suggest that 3-hydroxy fatty 40 3 acids can be applied in palaeoenvironmental studies to estimate past MAAT 41 and soil pH.

In this study, we designed a microcosm experiment to explore the composition of the bacterial community in the rhizosphere of maize and bulk soil by sequencing the V3-V4 region of the 16S rRNA gene on the Illumina system. 978–1239 OTUs (cut off level of 3%) were found in rhizosphere and bulk soil samples. Rhizosphere shared features with the bulk soil, such as predominance of Acidobacteria, Proteobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Gemmatimonadetes and TM7. At genus level, many of the dominant rhizosphere genera (Chitinophaga, Nitrospira, Flavobacterium, etc.) displayed different patterns of temporal changes in the rhizosphere as opposed to the bulk soil, showing rhizosphere has more impact on soil microorganisms. Besides, we found that significant growth-related dynamic changes in bacterial community structure were mainly associated with phylum Bacteroidetes, Proteobacteria and Actinobacteria (mainly genera Burkholderia, Flavisolibacter and Pseudomonas), indicating that different growth stages affected the bacterial community composition in maize soil. Furthermore, some unique genera in especial Plant-Growth Promoting Rhizobacteria (PGPR) such as Nonomuraea, Thiobacillus and Bradyrhizobium etc., which were beneficial for the plant growth appeared to be more abundant in the rhizosphere than bulk soil, indicating that the selectivity of root to rhizosphere microbial is an important mechanism leading to the differences in the bacteria community structure between rhizosphere and bulk soil.

To achieve a sufficient understanding of the spatial dynamics of terrestrial climate variability, new proxies and networks of data that cover thousands of years and run up to the present day are needed. Here we show the first Gram-negative bacterial 3-hydroxy fatty acid (3-OH-FA) based temperature and hydrological records from any palaeoclimate archive globally. The data, covering the last 9 ka before present (BP), are generated from an individual stalagmite, collected from Heshang Cave, located on a tributary of the Yangtze River, central China (30°27′N, 110°25′E; 294 m). Our results indicate a clear early-to-middle Holocene Climatic Optimum (8.0-6.0 ka BP) followed by a long-term monotonic cooling and increasing variability over the last 0.9 ka BP. The hydrological record shows two relatively long wet periods (8.8-5.9 ka BP and 3.0-0 ka BP) and one relative dry period (5.9-3.0 ka BP) in central China. We show that 3-OH-FA biomarkers hold promise as independent tools for palaeoclimate reconstruction, with the potential to deconvolve temperature and hydrological signals from an individual stalagmite.

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1. A total of 320-d-old Ross broilers were used in a 6-week study to investigate the effects of feeding lower energy and protein diets from d 8 to 14 on growth performance, blood profiles, and gene expression of leptin and myostatin. 2. Broilers were randomly allotted to 4 treatments, each treatment applied to 4 pens with 20 birds in each. During first week, all the birds were fed on a common starter diet (13.4 MJ ME/kg, 230 g/kg CP and 11.0 g/kg lysine). The birds were then subjected to their respective treatment diets from d 8 to 14. Treatment diets comprised two ME levels, 13.4 and 12.0 MJ/kg, each with two levels of CP, 230 and 184 g/kg. This was followed by feeding common starter and finisher diets for the last 4 weeks. 3. Dietary protein reduction resulted in poor performance and feed efficiency while energy reduction resulted in poor feed efficiency between d 8 and 14. From d 14 to 42 birds previously fed diets lower in energy and protein showed similar body weight gain and feed intake to well-fed birds. Moreover from d 8 to 14, birds fed on energy and protein-reduced diets had lower nutrient metabolisability coefficients. 4. The blood urea nitrogen (BUN) and relative weights of heart and breast muscle were lower in birds fed protein-reduced diets while energy reduction resulted in lower plasma glucose, abdominal fat and intestinal weight at d 14. At d 42, birds fed on the protein-reduced diets had lower BUN, breast muscle weight and small intestine length, while feeding on the energy-reduced diets resulted in lower abdominal fat. 5. Upregulated myostatin mRNA expression in breast muscle and downregulation of leptin mRNA expression in abdominal fat were observed in birds fed on protein and energy-reduced diets, respectively. 6. In conclusion, early nutrient reduction affected growth performance and produced lesser abdominal fat in broilers. Moreover, early energy and/or protein reduction could change muscle and fat metabolism by regulating the expressions of myostatin and leptin.