Sexually dimorphic control of affective state processing and empathic behaviors.

Recognizing the affective states of social counterparts and responding appropriately fosters successful social interactions. However, little is known about how the affective states are expressed and perceived and how they influence social decisions. Here, we show that male and female mice emit distinct olfactory cues after experiencing distress. These cues activate distinct neural circuits in the piriform cortex (PiC) and evoke sexually dimorphic empathic behaviors in observers. Specifically, the PiC → PrL pathway is activated in female observers, inducing a social preference for the distressed counterpart. Conversely, the PiC → MeA pathway is activated in male observers, evoking excessive self-grooming behaviors. These pathways originate from non-overlapping PiC neuron populations with distinct gene expression signatures regulated by transcription factors and sex hormones. Our study unveils how internal states of social counterparts are processed through sexually dimorphic mechanisms at the molecular, cellular, and circuit levels and offers insights into the neural mechanisms underpinning sex differences in higher brain functions.

Distinct Circuits From the Central Lateral Amygdala to the Ventral Part of the Bed Nucleus of Stria Terminalis Regulate Different Fear Memory.

BACKGROUND: The ability to differentiate stimuli that predict fear is critical for survival; however, the underlying molecular and circuit mechanisms remain poorly understood. METHODS: We combined transgenic mice, in vivo transsynaptic circuit-dissecting anatomical approaches, optogenetics, pharmacological methods, and electrophysiological recording to investigate the involvement of specific extended amygdala circuits in different fear memory. RESULTS: We identified the projections from central lateral amygdala (CeL) protein kinase C δ (PKCδ)-positive neurons and somatostatin (SST)-positive neurons to GABAergic (gamma-aminobutyric acidergic) and glutamatergic neurons in the ventral part of the bed nucleus of stria terminalis (vBNST). Prolonged optogenetic activation or inhibition of the PKCδCeL-vBNST pathway specifically reduced context fear memory, whereas the SSTCeL-vBNST pathway mainly reduced tone fear memory. Intriguingly, optogenetic manipulation of vBNST neurons that received the projection from PKCδCeL neurons exerted bidirectional regulation of context fear, whereas manipulation of vBNST neurons that received the projection from SSTCeL neurons could bidirectionally regulate both context and tone fear memory. We subsequently demonstrated the presence of δ and κ opioid receptor protein expression within the CeL-vBNST circuits, potentially accounting for the discrepancy between prolonged activation of GABAergic circuits and inhibition of downstream vBNST neurons. Finally, administration of an opioid receptor antagonist cocktail on the PKCδCeL-vBNST or SSTCeL-vBNST pathway successfully restored context or tone fear memory reduction induced by prolonged activation of the circuits. CONCLUSIONS: Together, these findings establish a functional role for distinct CeL-vBNST circuits in the differential regulation and appropriate maintenance of fear.

Gerhardtia tomentosa and Ossicaulis borealis (Agaricales, Lyophyllaceae)-Two new species from northeast China.

Background: Gerhardtia and Ossicaulis are two genera within the family Lyophyllaceae, which show an apparently poor species diversity worldwide. During the field investigation on wild macrofungi, six interesting collections within Gerhardtia and Ossicaulis genera are discovered in the northeastern China. Methods: To identify whether these collections of Gerhardtia and Ossicaulis are novel species, we performed phylogenetic analyzes using the following DNA regions: the internal transcribed spacer (ITS) region and the large subunit nuclear ribosomal RNA (nrLSU) region. Moreover, a traditional morphological method also be conducted based on both the macro-morphological and micro-morphological features. Results: The results indicated that these collections tested formed two independent lineages in each genus with a high support. In addition, they can easily be separated from all other taxa of the two genera in morphology. Based on the combination of morphological and molecular data, Gerhardtia tomentosa and Ossicaulis borealis, are confirmed as two new species to science. Discussions: This study provided a theoretical basis is for the two lyophylloid genera and indicated that the biodiversity resources of northeastern China might be underestimated.

Maternal and neonatal blood vitamin D status and neurodevelopment at 24 months of age: a prospective birth cohort study.

BACKGROUND: This study aimed to explore the relationship of 25-hydroxyvitamin D [25(OH)D] in three trimesters and at birth with neurodevelopment at 24 months of age. METHODS: From 2013 to 2016, pregnant women from the Shanghai Birth Cohort in China were recruited for the study. Altogether, 649 mother-infant pairs were included. Serum 25(OH)D was measured with mass spectrometry in three trimesters, and cord blood was divided into deficiency (< 20 and < 12 ng/mL, respectively), insufficiency (20-30 and 12-20 ng/mL, respectively), and sufficiency (≥ 30 and ≥ 20 ng/mL, respectively). Bayley-III scale was used to assess cognitive, language, motor, social-emotional, and adaptive behavior development at 24 months of age. The Bayley-III scores were grouped into quartiles, and scores within the lowest quartile were defined as suboptimal development. RESULTS: After adjusting for confounding factors, cord blood 25(OH)D in the sufficient group was positively correlated with cognitive [ß = 11.43, 95% confidence interval (CI) = 5.65-17.22], language (ß = 6.01, 95% CI = 1.67-10.3), and motor scores (ß = 6.43, 95% CI = 1.73-11.1); cord blood 25(OH)D in the insufficient group was also positively correlated with cognitive scores (ß = 9.42, 95% CI = 3.74-15.11). Additionally, sufficient vitamin D status in the four periods and persistent 25(OH)D ≥ 30 ng/mL throughout pregnancy were associated with a lower risk of suboptimal cognitive development in adjusted models, although the effects were attenuated after applying the false discovery rate adjustment. CONCLUSIONS: Cord blood 25(OH)D ≥ 12 ng/mL has a significant positive association with cognitive, language, and motor development at 24 months of age. Sufficient vitamin D status in pregnancy might be a protective factor for suboptimal neurocognition development at 24 months of age.

Somatostatin-Positive Neurons in the Rostral Zona Incerta Modulate Innate Fear-Induced Defensive Response in Mice.

Defensive behaviors induced by innate fear or Pavlovian fear conditioning are crucial for animals to avoid threats and ensure survival. The zona incerta (ZI) has been demonstrated to play important roles in fear learning and fear memory, as well as modulating auditory-induced innate defensive behavior. However, whether the neuronal subtypes in the ZI and specific circuits can mediate the innate fear response is largely unknown. Here, we found that somatostatin (SST)-positive neurons in the rostral ZI of mice were activated by a visual innate fear stimulus. Optogenetic inhibition of SST-positive neurons in the rostral ZI resulted in reduced flight responses to an overhead looming stimulus. Optogenetic activation of SST-positive neurons in the rostral ZI induced fear-like defensive behavior including increased immobility and bradycardia. In addition, we demonstrated that manipulation of the GABAergic projections from SST-positive neurons in the rostral ZI to the downstream nucleus reuniens (Re) mediated fear-like defensive behavior. Retrograde trans-synaptic tracing also revealed looming stimulus-activated neurons in the superior colliculus (SC) that projected to the Re-projecting SST-positive neurons in the rostral ZI (SC-ZIrSST-Re pathway). Together, our study elucidates the function of SST-positive neurons in the rostral ZI and the SC-ZIrSST-Re tri-synaptic circuit in mediating the innate fear response.

Distinct serotonergic pathways to the amygdala underlie separate behavioral features of anxiety.

Anxiety-like behaviors in mice include social avoidance and avoidance of bright spaces. Whether these features are distinctly regulated is unclear. We demonstrate that in mice, social and anxiogenic stimuli, respectively, increase and decrease serotonin (5-HT) levels in basal amygdala (BA). In dorsal raphe nucleus (DRN), 5-HT∩vGluT3 neurons projecting to BA parvalbumin (DRN5-HT∩vGluT3-BAPV) and pyramidal (DRN5-HT∩vGluT3-BAPyr) neurons have distinct intrinsic properties and gene expression and respond to anxiogenic and social stimuli, respectively. Activation of DRN5-HT∩vGluT3→BAPV inhibits 5-HT release via GABAB receptors on serotonergic terminals in BA, inducing social avoidance and avoidance of bright spaces. Activation of DRN5-HT∩vGluT3→BA neurons inhibits two subsets of BAPyr neurons via 5-HT1A receptors (HTR1A) and 5-HT1B receptors (HTR1B). Pharmacological inhibition of HTR1A and HTR1B in BA induces avoidance of bright spaces and social avoidance, respectively. These findings highlight the functional significance of heterogenic inputs from DRN to BA subpopulations in the regulation of separate anxiety-related behaviors.

Melanoleuca subgriseoflava and M. substridula-two new Melanoleuca species (Agaricales, Basidiomycota) described from China.

Two new Melanoleuca species, Melanoleuca subgriseoflava and M. substridula, are originally reported and described in China based on both morphological and molecular methods. Melanoleuca subgriseoflava, collected in Liaoning province, is mainly characterized by its greyish-brown to yellowish-grey pileus, creamy to light orange lamellae, greyish-yellow context, round and warted basidiospores and fusiform hymenial cystidia. Melanoleuca substridula, discovered in Sichuan province, is mainly characterized by its light brown to dark brown pileus, whitish lamellae, light brown to greyish-brown stipe, round and warted basidiospores and lack of any forms of cystidia. The phylogenetic relationships as well as divergence-time estimation were analyzed using the combined data set (ITS-nrLSU-RPB2), and the results showed that the two Melanoleuca species formed two distinct lineages. Based on the combination of morphological and molecular data, M. subgriseoflava and M. substridula are confirmed as two new species to science. A theoretical basis is provided for the species diversity of Melanoleuca.

Transcriptome analysis of genes associated with autolysis of Coprinus comatus.

Coprinus comatus, widely known as "Jituigu", is an important commodity and food in China. The yield of C. comatus, however, is substantially reduced by the autolysis of the fruiting bodies after harvest. To gain insight into the molecular mechanism underlying this autolysis, we divided the growth of C. comatus fruiting bodies into four stages: infant stage (I), mature stage (M), discolored stage (D), and autolysis stage (A). We then subjected these stages to de novo transcriptomic analysis using high-throughput Illumina sequencing. A total of 12,946 unigenes were annotated and analyzed with the Gene Ontology (GO), Clusters of Orthologous Groups of proteins (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG). We analyzed the differentially expressed genes (DEGs) between stages I and M, M and D, and D and A. Because the changes from M to D are thought to be related to autolysis, we focused on the DEGs between these two stages. We found that the pathways related to metabolic activity began to vary in the transition from M to D, including pathways named as autophagy-yeast, peroxisome, and starch and sucrose metabolism. This study also speculates the possible process of the autolysis of Coprinus comatus. In addition, 20 genes of interest were analyzed by quantitative real-time PCR to verify their expression profiles at the four developmental stages. This study, which is the first to describe the transcriptome of C. comatus, provides a foundation for future studies concerning the molecular basis of the autolysis of its fruiting bodies.

A Deep Mesencephalic Nucleus Circuit Regulates Licking Behavior.

Licking behavior is important for water intake. The deep mesencephalic nucleus (DpMe) has been implicated in instinctive behaviors. However, whether the DpMe is involved in licking behavior and the precise neural circuit behind this behavior remains unknown. Here, we found that the activity of the DpMe decreased during water intake. Inhibition of vesicular glutamate transporter 2-positive (VGLUT2+) neurons in the DpMe resulted in increased water intake. Somatostatin-expressing (SST+), but not protein kinase C-δ-expressing (PKC-δ+), GABAergic neurons in the central amygdala (CeA) preferentially innervated DpMe VGLUT2+ neurons. The SST+ neurons in the CeA projecting to the DpMe were activated at the onset of licking behavior. Activation of these CeA SST+ GABAergic neurons, but not PKC-δ+ GABAergic neurons, projecting to the DpMe was sufficient to induce licking behavior and promote water intake. These findings redefine the roles of the DpMe and reveal a novel CeASST-DpMeVGLUT2 circuit that regulates licking behavior and promotes water intake.

Three new Melanoleuca species (Agaricales, Basidiomycota) from north-eastern China, supported by morphological and molecular data.

Three new Melanoleuca species, M. chifengense, M. griseoflava and M. pallidorosea, were discovered in the northeast of China. Melanoleuca chifengense is morphologically characterised by its grey to yellowish-grey pileus, decurrent lamellae, grey to yellowish-brown stipe, yellowish-grey context, ellipsoid basidiospores with irregular warts and lack of hymenial cystidia. Melanoleuca griseoflava is mainly characterised by its greyish-brown pileus, adnexed to adnate lamellae, greyish-yellow context, fusiform cystidia and almost reticulate basidiospores. Melanoleuca pallidorosea is characterised by its pinkish-white pileus, white and decurrent lamellae, ellipsoid basidiospores with round and scattered warts and lack of hymenial cystidia. The phylogenetic relationship of the three species was determined by the analyses of the ITS region and the combined data matrix (ITS-nrLSU-RPB2), respectively. The results showed that the three species formed three independent lineages. Based on the combination of both morphological and molecular data, M. chifengense, M. griseoflava and M. pallidorosea were confirmed to be new species. The morphological similarities of the three new species is also discussed.

Nano-realgar suppresses lung cancer stem cell growth by repressing metabolic reprogramming.

BACKGROUND: Recent studies in cancer biology suggest that metabolic glucose reprogramming is a potential target for cancer treatment. However, little is known about drug intervention in the glucose metabolism of cancer stem cells (CSCs) and its related underlying mechanisms. METHODS: The crude realgar powder was Nano-grinded to meets the requirements of Nano-pharmaceutical preparations, and Nano-realgar solution (NRS) was prepared for subsequent experiments. Isolation and characterization of lung cancer stem cells (LCSCs) was performed by magnetic cell sorting (MACS) and immunocytochemistry, respectively. Cell viability and intracellular glucose concentration were detected by MTT assay and glucose oxidase (GOD) kit. Protein expressions related to metabolic reprogramming was detected by ELISA assay. Determination of the expression of HIF-1α and PI3K/Akt/mTOR pathways was carried out by RT-PCR and western blotting analysis. A subcutaneous tumor model in BALB/c-nu mice was successfully established to evaluate the effects of Nano-realgar on tumor growth and histological structure, and the expression of HIF-1α in tumor tissues was measured by immunofluorescence. RESULTS: Nano-realgar inhibits cell viability and induces glucose metabolism in LCSCs, and inhibits protein expression related to metabolic reprogramming in a time- and dose-dependent manner. Nano-realgar downregulated the expression of HIF-1α and PI3K/Akt/mTOR pathways in vitro and in vivo. Nano-realgar inhibits tumor growth and changes the histological structure of tumors through in vivo experiments and consequently inhibits the constitutive activation of HIF-1α signaling. CONCLUSIONS: These results reveal that Nano-realgar inhibits tumor growth in vitro and in vivo by repressing metabolic reprogramming. This inhibitory effect potentially related to the downregulation HIF-1α expression via PI3K/Akt/mTOR pathway.

Potential mechanisms underlying the ameliorative effect of Lactobacillus paracasei FZU103 on the lipid metabolism in hyperlipidemic mice fed a high-fat diet.

Lactobacillus paracasei FZU103, a probiotic previously isolated from the traditional brewing process of Hongqu rice wine, may have the beneficial effect of improving the disorder of lipid metabolism. This study aimed to determine the beneficial effects of L. paracasei FZU103 on improving hepatic lipid accumulation associated with hyperlipidemia. Results indicated that L. paracasei FZU103 intervention significantly inhibited the abnormal growth of body weight and epididymal white adipose tissue (eWAT), prevented the hypertrophy of epididymal adipocytes, ameliorated the biochemical parameters of serum and liver related to lipid metabolism in HFD-fed mice. Histological analysis also showed that the excessive accumulation oflipid dropletsin the livers induced by HFD-feeding was greatly alleviated by L. paracasei FZU103 intervention. In addition, L. paracasei FZU103 also promoted the excretion of bile acids (BAs) through feces. Metagenomic analysis revealed that oral supplementation with L. paracasei FZU103 significantly increased the relative abundance of Ruminococcus, Alistipes, Pseudoflavonifractor and Helicobacter, but decreased the levels of Blautia, Staphylococcos and Tannerella in HFD-fed mice. The relationships between lipid metabolic parameters and intestinal microbial phylotypes were also revealed by correlation heatmap and network. Furthermore, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS)-based liver metabolomics demonstrated that L. paracasei FZU103 had a significant regulatory effect on the metabolic pathways of glycerophospholipid metabolism, fatty acid degradation, fatty acid elongation, unsaturated fatty acids biosynthesis, riboflavin metabolism, glycerolipid metabolism, primary bile acid biosynthesis, arachidonic acid metabolism, etc. Additionally, L. paracasei FZU103 intervention regulated expression of hepatic genes involved in lipid metabolism and bile acid homeostasis, and promoted fecal excretion of intestinal BAs. These findings present new evidence supporting that L. paracasei FZU103 has the potential to improve lipid metabolism, and could be used as a potential functional food for the prevention of hyperlipidemia.

The association of serum vitamin K2 levels with Parkinson's disease: from basic case-control study to big data mining analysis.

Although it is known that inflammation is involved in Parkinson's disease (PD) pathogenesis and vitamin K2 (VK2) has anti-inflammatory effects, to date few studies have been reported on the relationship between VK2 and PD development. Herein we presented a case-control study involving 93 PD patients and 95 healthy controls. Overall, the serum VK2 level of PD patients (3.49 ± 1.68 ng/ml) was significantly lower than that of healthy controls (5.77 ± 2.71 ng/ml). When the PD patients were stratified by disease progression, we observed that the serum VK2 level of late stage patients was further decreased to 3.15 ± 1.18 ng/ml while the serum VK2 level of early stage patients was 3.92 ± 2.09 ng/ml. Furthermore, the curve analysis showed that the serum VK2 level decreased gradually with the increment of PD Hoehn-Yahr (H-Y) stage. We also confirmed the dysregulated inflammatory responses and coagulation cascades in PD patients by public dataset, which are associated to the decreased VK2 level. In summary, we found the serum VK2 level in PD patients is lower than that in healthy controls. The decrease of VK2 level may be related to the occurrence and progression of PD by loosening the regulation of inflammatory responses and coagulation cascades signal.

Whole-Brain Map of Long-Range Monosynaptic Inputs to Different Cell Types in the Amygdala of the Mouse.

The amygdala, which is involved in various behaviors and emotions, is reported to connect with the whole brain. However, the long-range inputs of distinct cell types have not yet been defined. Here, we used a retrograde trans-synaptic rabies virus to generate a whole-brain map of inputs to the main cell types in the mouse amygdala. We identified 37 individual regions that projected to neurons expressing vesicular glutamate transporter 2, 78 regions to parvalbumin-expressing neurons, 104 regions to neurons expressing protein kinase C-δ, and 89 regions to somatostatin-expressing neurons. The amygdala received massive projections from the isocortex and striatum. Several nuclei, such as the caudate-putamen and the CA1 field of the hippocampus, exhibited input preferences to different cell types in the amygdala. Notably, we identified several novel input areas, including the substantia innominata and zona incerta. These findings provide anatomical evidence to help understand the precise connections and diverse functions of the amygdala.

MeCP2 in cholinergic interneurons of nucleus accumbens regulates fear learning.

Methyl-CpG-binding protein 2 (MeCP2) encoded by the MECP2 gene is a transcriptional regulator whose mutations cause Rett syndrome (RTT). Mecp2-deficient mice show fear regulation impairment; however, the cellular and molecular mechanisms underlying this abnormal behavior are largely uncharacterized. Here, we showed that Mecp2 gene deficiency in cholinergic interneurons of the nucleus accumbens (NAc) dramatically impaired fear learning. We further found that spontaneous activity of cholinergic interneurons in Mecp2-deficient mice decreased, mediated by enhanced inhibitory transmission via α2-containing GABAA receptors. With MeCP2 restoration, opto- and chemo-genetic activation, and RNA interference in ChAT-expressing interneurons of the NAc, impaired fear retrieval was rescued. Taken together, these results reveal a previously unknown role of MeCP2 in NAc cholinergic interneurons in fear regulation, suggesting that modulation of neurons in the NAc may ameliorate fear-related disorders.

The protective mechanism of Lactobacillus plantarum FZU3013 against non-alcoholic fatty liver associated with hyperlipidemia in mice fed a high-fat diet.

Lactobacillus plantarum FZU3013, a probiotic previously isolated from the traditional brewing process of Hongqu rice wine, may have the beneficial effect of improving the disorders of lipid metabolism. This study aimed to investigate the role of L. plantarum FZU3013 in improving non-alcoholic fatty liver (NAFL) associated with hyperlipidemia in mice fed a high-fat diet. The results indicated that L. plantarum FZU3013 intervention significantly reduced the HFD-induced body weight gain and the abnormal levels of serum total triglycerides (TG), total cholesterol (TC) and low-density lipoprotein (LDL-C), and inhibited the excessive accumulation of liver lipids. In addition, L. plantarum FZU3013 also promoted the excretion of bile acids through feces. Metagenomic and multivariate statistical analysis revealed that L. plantarum FZU3013 made significant structural changes in the intestinal microbiome of the mice fed with HFD, in particular by modulating the relative abundance of some function related microbial phylotypes. Furthermore, ultra-performance liquid chromatography with quadruple-time of flight mass spectrometry (UPLC-QTOF/MS)-based liver metabolomics demonstrated that L. plantarum FZU3013 had a significant regulatory effect on the composition of liver metabolites in hyperlipidemic mice, especially on the levels of some important biomarkers involved in the pathways of glycerophospholipid metabolism, fatty acid degradation, fatty acid elongation, glycerolipid metabolism, primary bile acid biosynthesis, arachidonic acid metabolism, etc. Moreover, L. plantarum FZU3013 regulated the mRNA expression levels of the genes responsible for liver lipid and cholesterol metabolism. L. plantarum FZU3013 intervention increased the hepatic mRNA levels of cholesterol 7α-hydroxylase (CYP7A1) and the bile salt export pump (BSEP), suggesting enhanced bile acid synthesis and excretion from the liver. These findings present new evidence supporting that L. plantarum FZU3013 has the potential to improve lipid metabolism disorders through modulating specific intestinal microbial phylotypes and regulating hepatic lipid metabolism related genes, therefore it could be used as a potential functional food for the prevention of NAFL and hyperlipidemia.

Publisher Correction: Cannabinoid CB1 receptors in the amygdalar cholecystokinin glutamatergic afferents to nucleus accumbens modulate depressive-like behavior.

In the version of this article originally published, there were several errors in Fig. 4. In Fig. 4a, the title read '3D repeated optical inhibition after CSDS.' It should have read '3-day repeated optical inhibition after CSDS.' In Fig. 4c, two labels that should have been aligned with the time axis appeared in the wrong place in the figure. The ticks labeled 'SI' and 'Fiber implant' should have also been labeled with '10' and '14,' respectively. Additionally, in Fig. 4j, a label that should have been aligned with the time axis appeared in the wrong place in the figure. The tick labeled 'Fiber implant' should have also been labeled with '14.' The errors have been corrected in the print, PDF and HTML versions of the manuscript.

Cannabinoid CB1 receptors in the amygdalar cholecystokinin glutamatergic afferents to nucleus accumbens modulate depressive-like behavior.

Major depressive disorder is a devastating psychiatric disease that afflicts up to 17% of the world's population. Postmortem brain analyses and imaging studies of patients with depression have implicated basal lateral amygdala (BLA) dysfunction in the pathophysiology of depression. However, the circuit and molecular mechanisms through which BLA neurons modulate depressive behavior are largely uncharacterized. Here, in mice, we identified that BLA cholecystokinin (CCK) glutamatergic neurons mediated negative reinforcement via D2 medium spiny neurons (MSNs) in the nucleus accumbens (NAc) and that chronic social defeat selectively potentiated excitatory transmission of the CCKBLA-D2NAc circuit in susceptible mice via reduction of presynaptic cannabinoid type-1 receptor (CB1R). Knockdown of CB1R in the CCKBLA-D2NAc circuit elevated synaptic activity and promoted stress susceptibility. Notably, selective inhibition of the CCKBLA-D2NAc circuit or administration of synthetic cannabinoids in the NAc was sufficient to produce antidepressant-like effects. Overall, our studies reveal the circuit and molecular mechanisms of depression.

Genetic diversity of Lepista nuda (Agaricales, Basidiomycota) in Northeast China as indicated by SRAP and ISSR markers.

Lepista nuda is a popular wild edible mushroom that grows in China. In this study, we used ISSR and SRAP molecular markers to analyze the genetic diversity of 72 samples of L. nuda from eight populations in Northeast China. In total, six ISSR primers and five pairs of SRAP primers that produced clear and polymorphic banding profiles were selected for assessing L. nuda genetic diversity. The results revealed a high level of genetic variation among the 72 samples (94.4% polymorphism) but a low degree of gene flow among the populations. Among L. nuda populations, genetic distance was not correlated significantly with geographic distance. The antioxidant activity of the samples from each population was also tested and the result showed that all the selected samples had more than 60% DPPH scavenging activities. Nonetheless, the antioxidant activity diversity is not coincident with both the genetic diversity and the geographic distribution. The results indicate that ISSR and SRAP molecular markers are useful for studying the genetic diversity of L. nuda. The results also suggest that L. nuda populations in Northeast China require protection.

Three new species of Calocybe (Agaricales, Basidiomycota) from northeastern China are supported by morphological and molecular data.

Three new species, Calocybe aurantiaca, C. convexa, and C. decolorata, are described based on collections made in Shenyang City, Liaoning Province, China. The main characters of C. aurantiaca are its orange-yellow sporocarps and small and smooth basidiospores. Calocybe convexa is characterized by its orange-buff pileus, very small basidiospores, and tortuous stipe, whereas C. decolorata is mainly characterized by its gills that turn blue when bruised. The sequences of nuc rDNA ITS1-5.8S-ITS2 (ITS) and the 28S D1-D5 region of the Calocybe species were analyzed, and the results indicated that the three new species belonged to the genus Calocybe and differed from other species of Calocybe. The morphological similarities of the new species to other Calocybe species and the classification system within the genus Calocybe based on molecular data are also discussed. A key is provided for the Calocybe species as reported from China in order to facilitate future studies of the genus.