Plasma Catechols in Familial Dysautonomia: A Long-term Follow-up Study

This study tested whether familial dysautonomia (FD) involves progressive loss of noradrenergic nerves. Plasma levels of catechols, including dihydroxyphenylglycol (DHPG), norepinephrine (NE), dopamine (DA), and DOPA, were measured in 7 adult patients with FD and 50 healthy control subjects. FD patients were re-tested after a mean follow-up period of 13 years. Compared to controls, FD patients had low plasma levels of DHPG (P < 0.001), high DOPA and DA levels (P = 0.01, P = 0.0002), and high NE:DHPG (P < 0.0001), DA:NE (P = 0.0003), and DOPA:DHPG (P < 0.0001) ratios. At follow-up there were no changes in plasma levels of individual catechols; however, there were further increases in DOPA:DHPG ratios (mean 24 ± 7%, P = 0.01). In FD, plasma catechol profiles are sufficiently stable, at least over a decade, to be used as a biomarker of disease involvement. An increasing DOPA:DHPG ratio suggests slight but consistent, progressive loss of noradrenergic neurons.     

Isolation of high quality RNA from seeds and tubers of the Mexican yam bean (Pachyrhizus erosus)

Pachyrhizus erosus is a tuberous legume native to Central America that has great potential for development as a food crop. It produces both protein rich grain and starch filled tubers. There are two major limitations to its dietary use, the high levels of rotenone found in the grains and the low starch content of the tubers, both of which must be addressed, for development of the crop. The low variability of the existing gene pool of the genus limits the use of conventional plant breeding to address these problems. Genetic engineering technology is, therefore, being adopted. For this purpose, an efficient means of RNA isolation from yam bean tissues was developed. The quality of RNA obtained by this method was tested byin vitro translation and was sufficient for use in RT-PCR.     

Purification and primary structure of pro-aldosterone secretion inhibitory factor from bovine adrenal chromaffin cells

This report documents the purification and the complete primary structure of bovine aldosterone secretion inhibitory factor precursor (pro-ASIF). ASIF-(1-103) contains at position 69-103 of its carboxy-terminal end the formely identified 35-amino acid biologically active form, hence confirming the endogenous character of ASIF in the adrenal medulla. Compared to atrial natriuretic factor (ANF)-related peptide precursors, bovine ASIF displays 65% homology at the carboxy-terminal while the remaining amino-terminal part shows much more variability. Bovine pro-ASIF exhibits 73% homology with porcine pro-brain natriuretic peptide (BNP), a situation reminiscent of the relationship of pro-ANF in various species. When ANF- and BNP-related COOH-termini of bovine, porcine, human, rat, and chicken are compared, it appears that bovine ASIF and porcine BNP are closely related and belong to the same family which however appears to be much more heterogenous than the ANF-related family. These results strongly suggest that bovine ASIF is encoded by a precursor gene similar to the gene of BNP but different from the one encoding ANF.     

Inhibition of Janus Kinase 1 synergizes docetaxel sensitivity in prostate cancer cells

Prostate cancer (PCa) is the second most common malignancy and is the fifth leading cause of cancer mortality among men globally. Docetaxel-based therapy remains the first-line treatment for metastatic castration-resistant prostate cancer. However, dose-limiting toxicity including neutropenia, myelosuppression and neurotoxicity is the major reason for docetaxel dose reductions and fewer cycles administered, despite a recent study showing a clear survival benefit with increased total number of docetaxel cycles in PCa patients. Although previous studies have attempted to improve the efficacy and reduce docetaxel toxicity through drug combination, no drug has yet demonstrated improved overall survival in clinical trial, highlighting the challenges of improving the activity of docetaxel monotherapy in PCa. Herein, we identified 15 lethality hits for which inhibition could enhance docetaxel sensitivity in PCa cells via a high-throughput kinome-wide loss-of-function screen. Further drug-gene interactions analyses identified Janus kinase 1 (JAK1) as a viable druggable target with existing experimental inhibitors and FDA-approved drugs. We demonstrated that depletion of endogenous JAK1 enhanced docetaxel-induced apoptosis in PCa cells. Furthermore, inhibition of JAK1/2 by baricitinib and ruxolitinib synergizes docetaxel sensitivity in both androgen receptor (AR)–negative DU145 and PC3 cells, but not in the AR-positive LNCaP cells. In contrast, no synergistic effects were observed in cells treated with JAK2-specific inhibitor, fedratinib, suggesting that the synergistic effects are mainly mediated through JAK1 inhibition. In conclusion, the combination therapy with JAK1 inhibitors and docetaxel could be a useful therapeutic strategy in the treatment of prostate cancers.     

Matrix metalloproteinase-12 inhibitors: synthesis,structure-activity relationships and intestinal absorption of novel sugar-based biphenylsulfonamide carboxylates

MMP-12 is a validated target in pulmonary and cardiovascular diseases. The principal obstacles to clinical development of MMP-12 inhibitors are an inadequate selectivity for the target enzyme and a poor water solubility, with consequent poor oral bioavailability. We recently reported a new class of sugar-based arylsulfonamide carboxylates with a nanomolar activity for MMP-12, a good selectivity and an improved water solubility. In this study, we designed and synthesized new derivatives to characterize the structure-activity relationship (SAR) within this class of glycoconjugate inhibitors. All the new derivatives were tested on human recombinant MMP-12 and MMP-9 in order to evaluate their affinity and the selectivity for the target enzyme. Among them, the four most promising compounds were selected to assess their intestinal permeability using an ex vivo everted gut sac model. Given the high polarity and structural similarity to glucose, compound 3 was demonstrated to cross the intestinal membrane by using the facilitative GLUT2 transport.     

Structural characterization of the human Nogo-A functional domains. Solution structure of Nogo-40, a Nogo-66 receptor antagonist enhancing injured spinal cord regeneration.

The recent discovery of the Nogo family of myelin inhibitors and the Nogo-66 receptor opens up a very promising avenue for the development of therapeutic agents for treating spinal cord injury. Nogo-A, the largest member of the Nogo family, is a multidomain protein containing at least two regions responsible for inhibiting central nervous system (CNS) regeneration. So far, no structural information is available for Nogo-A or any of its structural domains. We have subcloned and expressed two Nogo-A fragments, namely the 182 residue Nogo-A(567-748) and the 66 residue Nogo-66 in Escherichia coli. CD and NMR characterization indicated that Nogo-A(567-748) was only partially structured while Nogo-66 was highly insoluble. Nogo-40, a truncated form of Nogo-66, has been previously shown to be a Nogo-66 receptor antagonist that is able to enhance CNS neuronal regeneration. Detailed NMR examinations revealed that a Nogo-40 peptide had intrinsic helix-forming propensity, even in an aqueous environment. The NMR structure of Nogo-40 was therefore determined in the presence of the helix-stabilizing solvent trifluoroethanol. The solution structure of Nogo-40 revealed two well-defined helices linked by an unstructured loop, representing the first structure of Nogo-66 receptor binding ligands. Our results provide the first structural insights into Nogo-A functional domains and may have implications in further designs of peptide mimetics that would enhance CNS neuronal regeneration.     

Herbivory on Acacia seedlings in an East African savanna

Trees critically affect the functioning of savanna ecosystems through their effects on nutrient cycling, water availability, and patterns of space use by wildlife. Therefore, whatever factors influence successful recruitment of tree seedlings are important filters controlling savanna ecosystem function. In African savannas, large mammals have been considered the most important agents of mortality for adult trees, but their impacts on tree seedlings are not well‐known. Similarly, the effects of rodents and invertebrates as seedling predators are largely unstudied in Africa. To assess the relative roles of large mammals, rodents, and invertebrates as predators of Acacia seedlings in an African savanna, we conducted two experiments in which we exposed Acacia drepanolobium seedlings to different guilds of herbivores. In the first experiment, seedlings exposed to rodent and invertebrate herbivores did not suffer greater damage than did seedlings exposed only to invertebrates, suggesting that invertebrates caused most of the damage to the seedlings. In the second experiment, 63% of seedlings exposed to all herbivores (large mammals, rodents, and invertebrates) suffered major damage or mortality in 14 days. Seedlings exposed to only rodents and invertebrates, however, suffered damage at a faster rate than did seedlings exposed to rodents, invertebrates, and large mammals, suggesting that small herbivores (rodents and invertebrates) might be compensating for the removal of large herbivores. Certain specific types of damage, such as cotyledon removal, were significantly more common in areas from which large mammals had been excluded, suggesting that the invertebrate herbivore community may differ between areas with and without large mammals. Overall, invertebrates caused the greatest damage to seedlings while rodents had relatively little effect and no seedlings were consumed or trampled by large mammals. Our results indicate that invertebrates can have a pronounced influence on seedling survival for a dominant savanna tree, which in turn may influence tree recruitment and ecosystem function.     

The complete nucleotide sequence of the mitochondrial genome of Tetraodon nigroviridis.

The fresh water pufferfish Tetraodon nigroviridis is a model organism for studying evolution of genome and gene functions, but its mitochondrial genome (mtDNA) sequence is still not available. We determined the complete nucleotide sequence of its mtDNA using shotgun sequencing. The T. nigroviridis mtDNA was 16,462 bp, and contained 13 protein coding genes, 22 tRNAs, 2 rRNAs and a major non-coding region. The gene order was identical to the common type of vertebrate mtDNA, whereas the G + C content in the sense strand was 46.9%, much higher than most other fish species. One hundred and three SNPs were detected in the control region of the mtDNA of 35 individuals, a majority of SNPs were detected in the 5' end of the control region. A phylogenetic study including 21 fish species was performed on concatenated amino acid sequences of 12 protein coding genes, and revealed that the T. nigroviridis was clustered with Fugu rubripes into a group. The complete mtDNA sequence and SNPs in its control region will be useful in studying fish evolution, in differentiating different Tetraodon species and in analyzing genetic diversity within T. nigroviridis.     

Viral Coat Protein Peptides with Limited Sequence Homology Bind Similar Domains of Alfalfa Mosaic Virus and Tobacco Streak Virus RNAs

An unusual and distinguishing feature of alfalfa mosaic virus (AMV) and ilarviruses such as tobacco streak virus (TSV) is that the viral coat protein is required to activate the early stages of viral RNA replication, a phenomenon known as genome activation. AMV-TSV coat protein homology is limited; however, they are functionally interchangeable in activating virus replication. For example, TSV coat protein will activate AMV RNA replication and vice versa. Although AMV and TSV coat proteins have little obvious amino acid homology, we recently reported that they share an N-terminal RNA binding consensus sequence (Ansel-McKinney et al., EMBO J. 15:5077–5084, 1996). Here, we biochemically compare the binding of chemically synthesized peptides that include the consensus RNA binding sequence and lysine-rich (AMV) or arginine-rich (TSV) environment to 3′-terminal TSV and AMV RNA fragments. The arginine-rich TSV coat protein peptide binds viral RNA with lower affinity than the lysine-rich AMV coat protein peptides; however, the ribose moieties protected from hydroxyl radical attack by the two different peptides are localized in the same area of the predicted RNA structures. When included in an infectious inoculum, both AMV and TSV 3′-terminal RNA fragments inhibited AMV RNA replication, while variant RNAs unable to bind coat protein did not affect replication significantly. The data suggest that RNA binding and genome activation functions may reside in the consensus RNA binding sequence that is apparently unique to AMV and ilarvirus coat proteins.     

Impacts of ungulates on the demography and diversity of small mammals in central Kenya

The impacts of ungulates on small mammals in an East African savanna habitat were investigated by monitoring the population and community responses of small mammals on replicated 4-ha plots from which ungulates had been excluded. The dominant small mammal in this habitat is the pouched mouse, Saccostomusmearnsi, a medium-sized murid rodent. Eight other small mammal species, including Arvicanthis sp., Mus sp., Mastomys sp., Dendromus sp., Crocidura sp., and, rarely, Tatera sp., Aethomys sp., and Acomys sp., were also captured. The dominant ungulates are elephant (Loxodonta africana), giraffe (Giraffa camelopardalis), Grevy's and common zebra (Equus grevyi and E. burchelli), buffalo (Syncerus cafer), eland (Taurotragus oryx), Grant's gazelle (Gazella granti), and domestic cattle. Within 1 year, S. mearnsi populations had responded dramatically to the exclusion of large mammals by a two-fold increase in density, a difference that was maintained through pronounced seasonal fluctuations in the second year. Though individual pouched mice showed no significant differences in their use of space with and without ungulates, male S. mearnsi maintained significantly higher body weights in the absence of ungulates, indicating that habitat quality had increased. One other species, Mastomys sp., also increased in the absence of ungulates. Overall, the small mammal community maintained relatively constant species diversity on the plots to which ungulates did not have access. On the plots to which ungulates did have access, on the other hand, there was a rapid 75% decrease in diversity in the control plots during one trapping session. Ungulates are most likely affecting small mammals through their effects on food quality, since there were no detectable differences in their exposure to predators, as determined by vegetative cover, in the absence of ungulates. These results demonstrate that ungulates can have strong and rapid impacts on small mammal abundance and diversity in East African savannas, an interaction which has not previously been given serious consideration. Received: 28 December 1997 / Accepted: 11 May 1998