Primates need to detect and recognize camouflaged animals in natural environments. Camouflage-breaking movements are often the only visual cue available to accomplish this. Specifically, sudden movements are often detected before full recognition of the camouflaged animal is made, suggesting that initial processing of motion precedes the recognition of motion-defined contours or shapes. What are the neuronal mechanisms underlying this initial processing of camouflaged motion in the primate visual brain? We investigated this question using intrinsic-signal optical imaging of macaque V1, V2 and V4, along with computer simulations of the neural population responses. We found that camouflaged motion at low speed was processed as a direction signal by both direction- and orientation-selective neurons, whereas at high-speed camouflaged motion was encoded as a motion-streak signal primarily by orientation-selective neurons. No population responses were found to be invariant to the camouflage contours. These results suggest that the initial processing of camouflaged motion at low and high speeds is encoded as direction and motion-streak signals in primate early visual cortices. These processes are consistent with a spatio-temporal filter mechanism that provides for fast processing of motion signals, prior to full recognition of camouflage-breaking animals. 相似文献
Three new compounds (1, 6, 9), with six known compounds (2–5, 7–8) were obtained from water-soluble extract of Cimicifuga dahurica (Turcz.) Maxim. by bioactivity-guided isolation. Their structures were elucidated by chemical and spectral analysis, including 1D, 2D NMR data and HRESIMS. H2O2-induced neurotoxicity on PC12 cells model were conducted to evaluate the neuro-protective capability of these compounds. The piscidic acid derivatives compounds 4–7 showed marked neuro-protective effect at certain concentration. 相似文献
The balance of osteoblasts and marrow adipocytes from bone marrow mesenchymal stem cells (BM-MSCs) maintains bone health. Under aging or other pathological stimuli, BM-MSCs will preferentially differentiate into marrow adipocytes and reduce osteoblasts, leading to osteoporosis. Long non-coding RNA differentiation antagonizing non-protein coding RNA (DANCR) participates in the osteogenic differentiation of human BM-MSCs, but the mechanism by which DANCR regulates the osteogenic differentiation of human BM-MSCs has not been fully explained. We observed that DANCR and prospero homeobox 1 (PROX1) were downregulated during osteogenic differentiation of human BM-MSCs, while miR-1301-3p had an opposite trend. DANCR overexpression decreased the levels of alkaline phosphatase, RUNX2, osteocalcin, Osterix in BM-MSCs after osteogenic induction, but DANCR silencing had the opposite result. Moreover, DANCR sponged miR-1301-3p to regulate PROX1 expression. miR-1301-3p overexpression reversed the suppressive role of DANCR elevation on the osteogenic differentiation of human BM-MSCs. Also, PROX1 elevation abolished the promoting role of miR-1301-3p overexpression on the osteogenic differentiation of human BM-MSCs. In conclusion, DANCR suppressed the osteogenic differentiation of human BM-MSCs through the miR-1301-3p/PROX1 axis, offering a novel mechanism by which DANCR is responsible for the osteogenic differentiation of human BM-MSCs.
Notch signaling determines and reinforces cell fate in bilaterally symmetric multicellular eukaryotes. Despite the involvement of Notch in many key developmental systems, human mutations in Notch signaling components have mainly been described in disorders with vascular and bone effects. Here, we report five heterozygous NOTCH1 variants in unrelated individuals with Adams-Oliver syndrome (AOS), a rare disease with major features of aplasia cutis of the scalp and terminal transverse limb defects. Using whole-genome sequencing in a cohort of 11 families lacking mutations in the four genes with known roles in AOS pathology (ARHGAP31, RBPJ, DOCK6, and EOGT), we found a heterozygous de novo 85 kb deletion spanning the NOTCH1 5′ region and three coding variants (c.1285T>C [p.Cys429Arg], c.4487G>A [p.Cys1496Tyr], and c.5965G>A [p.Asp1989Asn]), two of which are de novo, in four unrelated probands. In a fifth family, we identified a heterozygous canonical splice-site variant (c.743−1 G>T) in an affected father and daughter. These variants were not present in 5,077 in-house control genomes or in public databases. In keeping with the prominent developmental role described for Notch1 in mouse vasculature, we observed cardiac and multiple vascular defects in four of the five families. We propose that the limb and scalp defects might also be due to a vasculopathy in NOTCH1-related AOS. Our results suggest that mutations in NOTCH1 are the most common cause of AOS and add to a growing list of human diseases that have a vascular and/or bony component and are caused by alterations in the Notch signaling pathway. 相似文献
The Hani terrace paddyfield in Yunnan Province, China is categorized as a ‘constructed wetland’ under the Lamsar Convention
classification. The Hani terrace paddyfield ranges from an altitude of 144 to 2000 m above sea level (ASL) in the southern
slopes of the Ailao Mountains, angling down at a range of 15° to 75°. In this study, we investigated the ecosystem of the
terrace paddyfields in the Mengpin and Quanfuzhuang administrative villages located at the center of the cultural heritage
conservation district in the Hani terrace paddyfield. The Hani terrace paddyfield ecosystem structure is “forest-village-terrace
paddyfield-river” in the order of descending altitude. Soil and water samples were sequentially taken from forests, villages
and the terrace paddyfields to be able to study the vertical characteristics of Hani's terrace paddyfields. PO4-P and NH3-N in water were measured to test for water contamination. Seven soil nutrient factors were tested, including organic material
(OM), char and nitrogen ratio (C/N), pH, total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), and available
potassium (AK). Soil quality was also evaluated using the characteristics of the soil nutrient factors. Vertical changes in
the landscape, wetland types, wetland plants, hydrology and soil nutrients were characterized. Results showed that: (1) Hani's
terrace paddyfield can be divided into five types of wetlands; the rice varieties and cultivation patterns vary in each type
of wetland. (2) Hani's terrace paddyfield has a great capacity for water conservation and a strong ability to purify contaminants.
The impoundage of Hani's terrace paddyfield is about 5050 m3/hm2. Contaminants in the terrace paddyfield soils decrease exponentially with the decline in altitude. (3) Comparison of soil
quality in five different land use types indicates decreasing soil quality from forest to terrace land to terrace paddyfield
to water source. Except for headwater soil, single factors such as OM, TN and TP, and the comprehensive soil quality in individual
sampling zones tend to increase with altitude elevation. Comprehensive soil quality in the Quanfuzhuang sampling zone is better
than in the Mengpin sampling zone. Finally, a comparison of Hani's terrace paddyfield with plain paddyfields and natural wetlands
highlighted the vertical characteristics of Hani's terrace paddyfield.
__________
Translated from Acta Ecologica Sinica, 2006, 26(7): 2115–2124 [译自: 生态学报] 相似文献
The Hani terrace paddyfield in Yunnan Province,China is categorized as a 'constructed wetland' under the Lamsar Convention classification.The Hani terrace paddyfield ranges from an altitude of 144 to 2000 m above sea level (ASL) in the southern slopes of the Ailao Mountains,angling down at a range of 15°to 75°.In this study,we investigated the ecosystem of the terrace paddyfields in the Mengpin and Quanfuzhuang administrative villages located at the center of the cultural heritage conservation district in the Hani terrace paddy-field.The Hani terrace paddyfield ecosystem structure is "forest-village-terrace paddyfield-river" in the order of descending altitude.Soil and water samples were sequen-tially taken from forests,villages and the terrace paddy-fields to be able to study the vertical characteristics of Hani's terrace paddyfields.PO4-P and NH3-N in water were measured to test for water contamination.Seven soil nutrient factors were tested,including organic material (OM),char and nitrogen ratio (C/N),pH,total nitrogen (TN),total phosphorus (TP),available phosphorus (AP),and available potassium (AK).Soil quality was also eval-uated using the characteristics of the soil nutrient factors.Vertical changes in the landscape,wetland types,wetland plants,hydrology and soil nutrients were characterized.Results showed that:(1) Hani's terrace paddyfield can be divided into five types of wetlands; the rice varieties and cultivation patterns vary in each type of wetland.(2) Hani's terrace paddyfield has a great capacity for water conservation and a strong ability to purify contaminants.The impoundage of Hani's terrace paddyfield is about 5050 m3/hm2.Contaminants in the terrace paddyfield soils decrease exponentially with the decline in altitude.(3) Comparison of soil quality in five different land use types indicates decreasing soil quality from forest to ter-race land to terrace paddyfield to water source.Except for headwater soil,single factors such as OM,TN and TP,and the comprehensive soil quality in individual sampling zones tend to increase with altitude elevation.Comprehensive soil quality in the Quanfuzhuang sam-pling zone is better than in the Mengpin sampling zone.Finally,a comparison of Hani's terrace paddyfield with plain paddyfields and natural wetlands highlighted the vertical characteristics of Hani's terrace paddyfield. 相似文献
Brazzein is a small, intensely sweet protein. As a probe of the functional properties of its solvent-exposed loop, two residues (Arg-Ile) were inserted between Leu18 and Ala19 of brazzein. Psychophysical testing demonstrated that this mutant is totally tasteless. NMR chemical shift mapping of differences between this mutant and brazzein indicated that residues affected by the insertion are localized to the mutated loop, the region of the single alpha-helix, and around the Cys16-Cys37 disulfide bond. Residues unaffected by this mutation included those near the C-terminus and in the loop connecting the alpha-helix and the second beta-strand. In particular, several residues of brazzein previously shown to be essential for its sweetness (His31, Arg33, Glu41, Arg43, Asp50, and Tyr54) exhibited negligible chemical shift changes. Moreover, the pH dependence of the chemical shifts of His31, Glu41, Asp50, and Tyr54 were unaltered by the insertion. The insertion led to large chemical shift and pKa perturbation of Glu36, a residue shown previously to be important for brazzein's sweetness. These results serve to refine the known sweetness determinants of brazzein and lend further support to the idea that the protein interacts with a sweet-taste receptor through a multi-site interaction mechanism, as has been postulated for brazzein and other sweet proteins (monellin and thaumatin). 相似文献