α-bisabolol β-D-fucopyranoside as a potential modulator of β-amyloid peptide induced neurotoxicity: An in vitro & in silico study

Alzheimer’s disease (AD) is a multifaceted neurodegenerative disorder affecting the elderly people. For the AD treatment, there is inefficiency in the existing medication, as these drugs reduce only the symptoms of the disease. Since multiple pathological proteins are involved in the development of AD, searching for a single molecule targeting multiple AD proteins will be a new strategy for the management of AD. In view of this, the present study was designed to synthesize and evaluate the multifunctional neuroprotective ability of the sesquiterpene glycoside α-bisabolol β-D-fucopyranoside (ABFP) against multiple targets like acetylcholinesterase, oxidative stress and β-amyloid peptide aggregation induced cytotoxicity. In silico computational docking and simulation studies of ABFP with acetylcholinesterase (AChE) showed that it can interact with Asp74 and Thr75 residues of the enzyme. The in vitro studies showed that the compound possess significant ability to inhibit the AChE enzyme apart from exhibiting antioxidant, anti-aggregation and disaggregation properties. In addition, molecular dynamics simulation studies proved that the interacting residue between Aβ peptide and ABFP was found to be involved in Leu34 and Ile31. Furthermore, the compound was able to protect the Neuro2 a cells against Aβ_25-35 peptide induced toxicity. Overall, the present study evidently proved ABFP as a neuroprotective agent, which might act as a multi-target compound for the treatment of Alzheimer’s disease.     

A deuterohemin peptide protects a transgenic Caenorhabditis elegans model of Alzheimer’s disease by inhibiting Aβ1–42 aggregation

Alzheimer’s disease (AD) is a progressive neurodegenerative brain disease and is the most common cause of dementia in the elderly. The main hallmark of AD is the deposition of insoluble amyloid (Aβ) outside the neuron, leading to amyloid plaques and neurofibrillary tangles in the brain. Deuterohemin-Ala-His-Thr-Val-Glu-Lys (DhHP-6), a novel porphyrin-peptide, has both microperoxidase activity and cell permeability. In the present study, DhHP-6 efficiently inhibited the aggregation of Aβ and reduced the β-sheet percentage of Aβ from 89.1% to 78.3%. DhHP-6 has a stronger affinity (K_D = 100 ± 12 μM) for binding with Aβ at Phe⁴, Arg⁵, Val¹⁸, Glu¹¹ and Glu²². In addition, DhHP-6 (100 μM) significantly prolonged lifespan, alleviated paralysis and reduced Aβ plaque formation in the Aβ_1–42 transgenic Caenorhabditis elegans CL4176 model of AD. Our results demonstrate that DhHP-6 is a potential drug candidate that efficiently protects a transgenic C. elegans model of Alzheimer’s disease by inhibiting Aβ aggregation.     

Occurrence of Hylonycteris underwoodi (Chiroptera,Phyllostomidae) and Thyroptera tricolor (Chiroptera,Thyropteridae) in Honduras

The geographic distributions of Hylonycteris underwoodi and Thyroptera tricolor in Honduras have been established with specimens collected more than 50 years ago. Here, we describe the occurrence of these bat species captured in the historic city of Ciudad Blanca, Gracias a Dios in northeastern Honduras.     

Longevity and life history of cave bears – a review and novel data from tooth cementum and relative emergence of permanent dentition

Abstract

Longevity and other life history variables are key to understanding evolutionary processes and the biology of extinct animals. For the past 20 years, the lifespan of cave bears received an increased interest. Studies focusing on incremental lines of tooth cementum resulted in detailed mortality patterns from different localities. In this review, we summarise literature on age estimation as well as mortality of different European cave bear localities and present novel data on longevity from 94 teeth originating from 20 European localities. Additionally, the relative tooth emergence pattern of the permanent dentition is investigated under the Schultz’s rule framework of possible life history implications. For this, the known sequences of extant bear species are compared with the one of cave bears. Our results suggest that the typical duration of the life of cave bears was 19 years but data from literature show that in rare cases ages of up to 30–32 years were achieved. Additionally, we present the oldest known age for the Middle Pleistocene cave bear Ursus deningeri, 29 years. The tooth eruption pattern of cave bears exhibits a heterochronic shift that implies, under the assumption of Schulz’ rule, a slightly faster life history than closely related species.     

Synthetic biology and metabolic engineering of actinomycetes for natural product discovery

Actinomycetes are one of the most valuable sources of natural products with industrial and medicinal importance. After more than half a century of exploitation, it has become increasingly challenging to find novel natural products with useful properties as the same known compounds are often repeatedly re-discovered when using traditional approaches. Modern genome mining approaches have led to the discovery of new biosynthetic gene clusters, thus indicating that actinomycetes still harbor a huge unexploited potential to produce novel natural products. In recent years, innovative synthetic biology and metabolic engineering tools have greatly accelerated the discovery of new natural products and the engineering of actinomycetes. In the first part of this review, we outline the successful application of metabolic engineering to optimize natural product production, focusing on the use of multi-omics data, genome-scale metabolic models, rational approaches to balance precursor pools, and the engineering of regulatory genes and regulatory elements. In the second part, we summarize the recent advances of synthetic biology for actinomycetal metabolic engineering including cluster assembly, cloning and expression, CRISPR/Cas9 technologies, and chassis strain development for natural product overproduction and discovery. Finally, we describe new advances in reprogramming biosynthetic pathways through polyketide synthase and non-ribosomal peptide synthetase engineering. These new developments are expected to revitalize discovery and development of new natural products with medicinal and other industrial applications.     

Population biology and breeding cycle of the burrowing shrimp Callichirus seilacheri (Decapoda,Callianassidae) from the eastern tropical Pacific

Year-round continuous reproduction in tropical regions is an established paradigm in marine ecology. In this study, we tested this paradigm using the ghost shrimp Callichirus seilacheri from the tropical eastern Pacific as a model species. We also examined size-frequency distribution, sex ratio, and recruitment cycle to contribute to the biological knowledge of this species. To this end, a total of 456 individuals of C. seilacheri were collected during 12 months of sampling. Population structure was symmetrical for both sexes, and the overall sex ratio did not differ from evenness. Males outnumbered females in smaller size classes, though, revealing a potential sex-dependent mortality in small individuals. The breeding pattern followed the well-marked seasonal regime of the region, with ovigerous females registered during the rainy season. While natural variation in the seawater temperature had no influence on reproduction of this species, changes in water salinity possibly triggered the appearance of egg-bearing females in the population. Recruitment occurred throughout the year but was more intense during the dry season, following the appearance of ovigerous females. The adaptability of the life cycle of C. seilacheri to the seasonal climate provides further evidence that reproduction in tropical species is not always continuous.     

Tindaria kretensis n. sp., a new deep water protobranch (Bivalvia) from the Early Pliocene of Crete (Southern Greece)

Tindaria kretensis n. sp., a minute deep-water protobranch, is described from Early Pliocene marls cropping out in the Voutes section, northern Crete Island. This is one of the few fossil records of Tindaria from the Mediterranean area, the first well documented for the Neogene. Tindaria is an almost cosmopolitan deep-water genus, absent from the modern Mediterranean. Its occurrence in the Early Pliocene is in agreement with what is known about the past psychrospheric conditions in the Mediterranean.     

同域分布的黑麂和小麂的时空生态位分化

生态位分化是解释物种共存的重要理论。Schonenr认为空间维度对生态位差异形成的影响程度最高,营养维度次之,时间维度则最后被启动。为验证这一假说,我们于2018年12月至2019年11月,在浙江清凉峰国家级自然保护区龙塘山区域采用公里网格法布设52台红外相机,对同域分布且食性相似的黑麂和小麂种群进行监测,计算平均拍摄率,分析不同季节黑麂和小麂对不同植被类型、海拔、坡位、水源距离的选择差异,并运用核密度估计法分析二者日活动节律及重叠程度。结果显示,(1)黑麂和小麂对空间生态位的选择出现分化：黑麂偏好针阔混交林,主要栖息于1 301～1 500 m的高海拔地区,回避下坡位和谷地,在距离水源较近的区域内活动频繁;小麂则偏好落叶阔叶林,主要栖息于901～1 100 m的中海拔地区,偏好中坡位,回避谷地,对水源距离没有明显的选择倾向。(2)黑麂和小麂均为晨昏性活动的昼行性动物,二者全年日活动节律重叠程度较高(Δ4=0.86),仅冬季较低(Δ1=0.65)。上述结果支持Schonenr的假说：首先,空间维度对物种生态位分化的影响大于时间维度,龙塘山区域黑麂和小麂主要通过选择不同的栖息地来增加空间...