A potential rhodium cancer therapy: Studies of a cytotoxic organorhodium(I) complex that binds DNA

Described is a novel organorhodium(I) complex that is cytotoxic to the colon cancer cell line HCT116 and alters cell migration, DNA replication, and DNA condensation. Most importantly, the mechanism observed is not seen for the parent organorhodium dimer complex [{RhCl(COD)}₂], RhCl₃, or the free ligand/proligands (COD and 1-ⁿbutyl-3-methylimidazolium chloride). Thus, the activity of this organorhodium complex is attributable to its unique structure.     

The Determinants of Traditional Medicine Use in Northern Tanzania: A Mixed-Methods Study

Introduction

Traditional medicines are an important part of healthcare in sub-Saharan Africa, and building successful disease treatment programs that are sensitive to traditional medicine practices will require an understanding of their current use and roles, including from a biomedical perspective. Therefore, we conducted a mixed-method study in Northern Tanzania in order to characterize the extent of and reasons for the use of traditional medicines among the general population so that we can better inform public health efforts in the region.

Methods

Between December 2013 and June 2014 in Kilimanjaro, Tanzania, we conducted 5 focus group discussions and 27 in-depth interviews of key informants. The data from these sessions were analyzed using an inductive framework method with cultural insider-outsider coding. From these results, we developed a structured survey designed to test different aspects of traditional medicine use and administered it to a random sample of 655 adults from the community. The results were triangulated to explore converging and diverging themes.

Results

Most structured survey participants (68%) reported knowing someone who frequently used traditional medicines, and the majority (56%) reported using them themselves in the previous year. The most common uses were for symptomatic ailments (42%), chronic diseases (15%), reproductive problems (11%), and malaria/febrile illnesses (11%). We identified five major determinants for traditional medicine use in Northern Tanzania: biomedical healthcare delivery, credibility of traditional practices, strong cultural identities, individual health status, and disease understanding.

Conclusions

In order to better formulate effective local disease management programs that are sensitive to TM practices, we described the determinants of TM use. Additionally, we found TM use to be high in Northern Tanzania and that its use is not limited to lower-income areas or rural settings. After symptomatic ailments, chronic diseases were reported as the most common reason for TM use which may be particularly important in Northern Tanzania where non-communicable diseases are a rapidly growing burden.     

A charge reversal differentiates (p)ppGpp synthesis by monofunctional and bifunctional Rel proteins

A major regulatory mechanism evolved by microorganisms to combat stress is the regulation mediated by (p)ppGpp (the stringent response molecule), synthesized and hydrolyzed by Rel proteins. These are divided into bifunctional and monofunctional proteins based on the presence or absence of the hydrolysis activity. Although these proteins require Mg(2+) for (p)ppGpp synthesis, high Mg(2+) was shown to inhibit this reaction in bifunctional Rel proteins from Mycobacterium tuberculosis and Streptococcus equisimilis. This is not a characteristic feature in enzymes that use a dual metal ion mechanism, such as DNA polymerases that are known to carry out a similar pyrophosphate transfer reaction. Comparison of polymerase Polbeta and Rel(Seq) structures that share a common fold led to the proposal that the latter would follow a single metal ion mechanism. Surprisingly, in contrast to bifunctional Rel, we did not find inhibition of guanosine 5'-triphosphate, 3'-diphosphate (pppGpp) synthesis at higher Mg(2+) in the monofunctional RelA from Escherichia coli. We show that a charge reversal in a conserved motif in the synthesis domains explains this contrast; an RXKD motif in the bifunctional proteins is reversed to an EXDD motif. The differential response of these proteins to Mg(2+) could also be noticed in fluorescent nucleotide binding and circular dichroism experiments. In mutants where the motifs were reversed, the differential effect could also be reversed. We infer that although a catalytic Mg(2+) is common to both bifunctional and monofunctional proteins, the latter would utilize an additional metal binding site formed by EXDD. This work, for the first time, brings out differences in (p)ppGpp synthesis by the two classes of Rel proteins.     

Dysferlin and the plasma membrane repair in muscular dystrophy

Muscular dystrophy covers a group of genetically determined disorders that cause progressive weakness and wasting of the skeletal muscles. Dysferlin was identified as a gene mutated in limb-girdle muscular dystrophy (type 2B) and Miyoshi myopathy. The discovery of dysferlin revealed a new family of proteins, known as the ferlin family, which includes four different genes. Recent work suggests the function of dysferlin in membrane repair and demonstrates that defective membrane repair is a novel mechanism of muscle degeneration. These findings reveal the importance of a basic cellular function in skeletal muscle and a new class of muscular dystrophy where the defect lies in the maintenance, not the structure, of the plasma membrane. Here, we discuss the current knowledge of dysferlin function in the repair of the plasma membrane of the skeletal muscle cells.     

hiPSC-derived hepatocytes closely mimic the lipid profile of primary hepatocytes: A future personalised cell model for studying the lipid metabolism of the liver

Hepatocyte-like cells (HLCs) differentiated from human-induced pluripotent stem cells offer an alternative platform to primary human hepatocytes (PHHs) for studying the lipid metabolism of the liver. However, despite their great potential, the lipid profile of HLCs has not yet been characterized. Here, we comprehensively studied the lipid profile and fatty acid (FA) metabolism of HLCs and compared them with the current standard hepatocyte models: HepG2 cells and PHHs. We differentiated HLCs by five commonly used methods from three cell lines and thoroughly characterized them by gene and protein expression. HLCs generated by each method were assessed for their functionality and the ability to synthesize, elongate, and desaturate FAs. In addition, lipid and FA profiles of HLCs were investigated by both mass spectrometry and gas chromatography and then compared with the profiles of PHHs and HepG2 cells. HLCs resembled PHHs by expressing hepatic markers: secreting albumin, lipoprotein particles, and urea, and demonstrating similarities in their lipid and FA profile. Unlike HepG2 cells, HLCs contained low levels of lysophospholipids similar to the content of PHHs. Furthermore, HLCs were able to efficiently use the exogenous FAs available in their medium and simultaneously modify simple lipids into more complex ones to fulfill their needs. In addition, we propose that increasing the polyunsaturated FA supply of the culture medium may positively affect the lipid profile and functionality of HLCs. In conclusion, our data showed that HLCs provide a functional and relevant model to investigate human lipid homeostasis at both molecular and cellular levels.     

Heterologous expression of <Emphasis Type="Italic">PDH47</Emphasis> confers drought tolerance in <Emphasis Type="Italic">indica</Emphasis> rice

Jerusalem artichoke (Helianthus tuberosus L.) cultivars are conserved in genebanks for use in breeding and horticultural research programs. Jerusalem artichoke collections are particularly vulnerable to environmental and biological threats because they are often maintained in the field. These field collections could be securely conserved in genebanks if improved cryopreservation methods were available. This work used four Jersualem artichoke cultivars (‘Shudi’, ‘M6’, ‘Stampede’, and ‘Relikt’) to improve upon an existing procedure. Four steps were optimized and the resulting procedure is as follows: preculture excised shoot tips (2–3 mm) in liquid MS medium supplemented with 0.4 M sucrose for 3 days, osmoprotect shoot tips in loading solution for 30 min, dehydrate with plant vitrification solution 2 for 15 min before rapid cooling in liquid nitrogen, store in liquid nitrogen, rapidly rewarm in MS liquid medium containing 1.2 M sucrose, and recover on MS medium supplemented with 0.1 mg L^?1 GA₃ for 3–5 days in the dark and then on the same medium for 4–6 weeks in the light (14 h light/10 h dark). After cryopreservation, Jerusalem artichoke cultivar ‘Shudi’ had the highest survival (93%) and regrowth (83%) percentages. Cultivars ‘M6’, ‘Stampede’, and ‘Relikt’ achieved survival and regrowth percentages ranging from 44 to 72%, and 37–53%, respectively. No genetic changes, as assessed by using simple sequence repeat markers, were detected in plants regenerated after LN exposure in Jerusalem artichoke cultivar ‘Shudi’. Differential scanning calorimetry analyses were used to investigate the thermal activities of the tissues during the cryopreservation process and it was determined that loading with 2.0 M sucrose and 0.4 M sucrose dehydrated the shoot tips prior to treatment with PVS2. Histological observations revealed that the optimized droplet vitrification protocol caused minimal cellular damage within the meristem cells of the shoot tips.     

L-carnitine increases liver alpha-tocopherol and lowers liver and plasma triglycerides in aging ovariectomized rats

The objective of this study was to determine whether dietary L-carnitine can influence the status of alpha-tocopherol, retinol and selected lipid parameters in aging ovariectomized rats, an animal model for the menopausal state. Fourteen Fisher-344 female rats 18 months old were acclimated for 4 weeks and ovarectomized. Seven rats per treatment were assigned to either a control group fed ad libitum AIN-93M diet or a carnitine group fed the same diet supplemented with L-carnitine. After an 8-week feeding period, blood and selected tissues were taken for analyses. No differences were noted in food intake, body weight, or organ weights due to L-carnitine. Dietary carnitine significantly increased liver alpha-tocopherol and tended to increase plasma alpha-tocopherol (P<.09). No changes in alpha-tocopherol were observed in other tissues including the brain, lungs and retroperitoneal fat. Retinol levels in plasma and tissues were not affected by supplemental L-carnitine. Significant decreases in liver and plasma triglyceride (TG) levels were noted, suggesting increased utilization of fatty acids. No differences were observed in the fatty acid profile of tissues. The results provide evidence that dietary supplementation of L-carnitine enhances the alpha-tocopherol status and improves the utilization of fat leading to lowering of the liver and plasma levels of TG in aging ovariectomized rats. Whether supplemental L-carnitine may be of benefit to postmenopausal women in lowering plasma TG and improving the antioxidant status remains to be studied.