50 research outputs found
Possible Fruit Protein Effects on Primate Communities in Madagascar and the Neotropics
The ecological factors contributing to the evolution of tropical vertebrate communities are still poorly understood. Primate communities of the tropical Americas have fewer folivorous but more frugivorous genera than tropical regions of the Old World and especially many more frugivorous genera than Madagascar. Reasons for this phenomenon are largely unexplored. We developed the hypothesis that Neotropical fruits have higher protein concentrations than fruits from Madagascar and that the higher representation of frugivorous genera in the Neotropics is linked to high protein concentrations in fruits. Low fruit protein concentrations in Madagascar would restrict the evolution of frugivores in Malagasy communities.We reviewed the literature for nitrogen concentrations in fruits from the Neotropics and from Madagascar, and analyzed fruits from an additional six sites in the Neotropics and six sites in Madagascar. Fruits from the Neotropical sites contain significantly more nitrogen than fruits from the Madagascar sites. Nitrogen concentrations in New World fruits are above the concentrations to satisfy nitrogen requirements of primates, while they are at the lower end or below the concentrations to cover primate protein needs in Madagascar.Fruits at most sites in the Neotropics contain enough protein to satisfy the protein needs of primates. Thus, selection pressure to develop new adaptations for foods that are difficult to digest (such as leaves) may have been lower in the Neotropics than in Madagascar. The low nitrogen concentrations in fruits from Madagascar may contribute to the almost complete absence of frugivorous primate species on this island
Genome-wide Analyses Identify KIF5A as a Novel ALS Gene
To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.Peer reviewe
Mammal responses to global changes in human activity vary by trophic group and landscape
Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in human–wildlife interactions along gradients of human influence.Peer reviewe
Association of Variants in the SPTLC1 Gene With Juvenile Amyotrophic Lateral Sclerosis
Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.Objective: To identify the genetic variants associated with juvenile ALS.Design, Setting, and Participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism.Main Outcomes and Measures: De novo variants present only in the index case and not in unaffected family members.Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway.Conclusions and Relevance: These data broaden the phenotype associated with SPTLC1 and suggest that patients presenting with juvenile ALS should be screened for variants in this gene.</p
Genome-wide structural variant analysis identifies risk loci for non-Alzheimer’s dementias
We characterized the role of structural variants, a largely unexplored type of genetic variation, in two non-Alzheimer’s dementias, namely Lewy body dementia (LBD) and frontotemporal dementia (FTD)/amyotrophic lateral sclerosis (ALS). To do this, we applied an advanced structural variant calling pipeline (GATK-SV) to short-read whole-genome sequence data from 5,213 European-ancestry cases and 4,132 controls. We discovered, replicated, and validated a deletion in TPCN1 as a novel risk locus for LBD and detected the known structural variants at the C9orf72 and MAPT loci as associated with FTD/ALS. We also identified rare pathogenic structural variants in both LBD and FTD/ALS. Finally, we assembled a catalog of structural variants that can be mined for new insights into the pathogenesis of these understudied forms of dementia
Blockchain technology adoption for improved environmental supply chain performance
Due to the complexity of building supply chain resilience (SCR) towards long-term environmental sustainability amendments, the use of emerging technologies such as Blockchain Technology (BCT) can be adopted as an innovative tool to enhance the sustainability and resilience of supply chains, especially in uncertain environments. Drawing on the Knowledge-Based View (KBV) and Dynamic Capability View (DCV), this research aims to demonstrate how the adoption of BCT can enhance the environmental supply chain performance (SCP). A total of 603 valid surveys were collected from respondents from manufacturing and service organizations in Egypt. The collected data were analyzed using structural equation modelling, and results revealed that BCT adoption alone had a negative direct impact on environmental SCP. However, when this relationship was mediated by SCR and sequentially mediated by customer integration and green customer information sharing, the results were positive. This research presents insights on how organizations can adapt to dynamic business environments, and, in addition, it extends the theories of KBV and DCV in an empirical contribution by filling the gap in understanding regarding how environmental SCP can be enhanced through the adoption of BCT
Enzymatic and binding effects of atrial natriuretic factor in glomeruli and nephrons
Enzymatic and binding effects of atrial natriuretic factor in glomeruli and nephrons. Atrial natriuretic factor (ANF) has been suggested to exert a tubular effect on the mammalian nephron, perhaps in part by interacting with other hormones. In the present study, the effect of ANF was examined on glomeruli (Gm) and different renal tubule segments including medullary (MAL) and cortical thick ascending limb (CAL) and cortical (CCT), outer medullary (OMCT) and inner medullary collecting tubules (IMCT). This effect of ANF was assessed by alteration in adenylate cyclase and cGMP in the various nephron segments in the presence and absence of arginine vasopressin (AVP), parathyroid hormone (PTH) and calcitonin (SCT). An effect of ANF (10-8 m) was not demonstrated on adenylate cyclase (fmol cAMP formed/30 min/µg protein) in Gm, CAL, MAL, CCT, OMCT or IMCT. Nor did ANF (10-8 m) interfere with the effect of PTH (5 IU/ml) on the Gm (PTH 35.1 ± 3.7 vs. PTH + ANF 32.5 ± 1.8, NS), CAL (PTH 50.5 ± 10.9 vs. PTH + ANF 46.2 ± 1.4, NS) or AVP (10-8 m) on the CCT (AVP 40.8 ± 6.6 vs. AVP + ANF 33.0 ±3.1, NS), OMCT (AVP 56.0 ±11.8 vs. AVP + ANF 42.1 ± 6.7, NS), IMCT (AVP 66.5 ± 4.6 vs. AVP + ANF 53.5 ± 7.0, NS) or MAL (AVP 15.5 ± 1.6 vs. AVP + ANF 14.0 ± 2.6, NS). ANF also did not affect SCT (1.5 × 10-8 M)-induced adenylate cyclase on CCT (SCT 69.8 ± 11.3 vs. SCT + ANF 79.9 ± 7.2, NS). ANF (10-8 M), however, significantly increased cGMP in the Gm (6.4 ± 1.7 to 121.3 ± 32.4 fmol/µg protein, P < 0.001) and IMCT (0.63 ± 0.16 to 1.46 ± 0.29 fmol/µg protein, P < 0.05). However, no effect of ANF on cGMP was observed in the CAL, CCT, OMCT, and MAL even at 10-7 M ANF. PTH (5 IU/ml) did not alter either basal or ANF-stimulated cGMP in the Gm. Also, specific ANF binding was studied in the microdissected IMCT. Kd was 6.08 × 10-9 M and Bmax was 8.07 × 10-11 M. These results suggest that ANF does not exert a direct effect on the cellular action of AVP, PTH or SCT, but may exert a significant physiological role in the Gm and IMCT by increasing cGMP