Water deficit induces chlorophyll degradation via the ‘PAO/phyllobilin’ pathway in leaves of homoio‐ (Craterostigma pumilum) and poikilochlorophyllous (Xerophyta viscosa) resurrection plants

Angiosperm resurrection plants exhibit poikilo‐ or homoiochlorophylly as a response to water deficit. Both strategies are generally considered as effective mechanisms to reduce oxidative stress associated with photosynthetic activity under water deficiency. The mechanism of water deficit‐induced chlorophyll (Chl) degradation in resurrection plants is unknown but has previously been suggested to occur as a result of non‐enzymatic photooxidation. We investigated Chl degradation during dehydration in both poikilochlorophyllous (Xerophyta viscosa) and homoiochlorophyllous (Craterostigma pumilum) species. We demonstrate an increase in the abundance of PHEOPHORBIDE a OXYGENASE (PAO), a key enzyme of Chl breakdown, together with an accumulation of phyllobilins, that is, products of PAO‐dependent Chl breakdown, in both species. Phyllobilins and PAO levels diminished again in leaves from rehydrated plants. We conclude that water deficit‐induced poikilochlorophylly occurs via the well‐characterized PAO/phyllobilin pathway of Chl breakdown and that this mechanism also appears conserved in a resurrection species displaying homoiochlorophylly. The roles of the PAO/phyllobilin pathway during different plant developmental processes that involve Chl breakdown, such as leaf senescence and desiccation, fruit ripening and seed maturation, are discussed.     

NPQ(T): a chlorophyll fluorescence parameter for rapid estimation and imaging of non‐photochemical quenching of excitons in photosystem‐II‐associated antenna complexes

In photosynthesis, light energy is absorbed by light‐harvesting complexes and used to drive photochemistry. However, a fraction of absorbed light is lost to non‐photochemical quenching (NPQ) that reflects several important photosynthetic processes to dissipate excess energy. Currently, estimates of NPQ and its individual components (q_E, q_I, q_Z and q_T) are measured from pulse‐amplitude‐modulation (PAM) measurements of chlorophyll fluorescence yield and require measurements of the maximal yield of fluorescence in fully dark‐adapted material (F_m), when NPQ is assumed to be negligible. Unfortunately, this approach requires extensive dark acclimation, often precluding widespread or high‐throughput use, particularly under field conditions or in imaging applications, while introducing artefacts when F_m is measured in the presence of residual photodamaged centres. To address these limitations, we derived and characterized a new set of parameters, NPQ_(T), and its components that can be (1) measured in a few seconds, allowing for high‐throughput and field applications; (2) does not require full relaxation of quenching processes and thus can be applied to photoinhibited materials; (3) can distinguish between NPQ and chloroplast movements; and (4) can be used to image NPQ in plants with large leaf movements. We discuss the applications benefits and caveats of both approaches.     

Comparative efficacy of gypsy moth (Lepidoptera: Erebidae) entomopathogens on transgenic blight‐tolerant and wild‐type American,Chinese, and hybrid chestnuts (Fagales: Fagaceae)

American chestnut (Castanea dentata [Marsh.] Borkh.) was once the dominant hardwood species in Eastern North America before an exotic fungal pathogen, Cryphonectria parasitica (Murrill) Barr, functionally eliminated it across its range. One promising approach toward restoring American chestnut to natural forests is development of blight‐tolerant trees using genetic transformation. However, transformation and related processes can result in unexpected and unintended phenotypic changes, potentially altering ecological interactions. To assess unintended tritrophic impacts of transgenic American chestnut on plant–herbivore interactions, gypsy moth (Lymantria dispar L.) caterpillars were fed leaf disks excised from two transgenic events, Darling 54 and Darling 58, and four control American chestnut lines. Leaf disks were previously treated with an LD₅₀ dose of either the species‐specific Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) or the generalist pathogen Bacillus thuringiensis subsp. kurstaki (Btk). Mortality was quantified and compared to water blank controls. Tree genotype had a strong effect on the efficacies of both pathogens. Larval mortality from Btk‐treated foliage from only one transgenic event, Darling 54, differed from its isogenic progenitor, Ellis 1, but was similar to an unrelated wild‐type American chestnut control. LdMNPV efficacy was unaffected by genetic transformation. Results suggest that although genetic modification of trees may affect interactions with other nontarget organisms, this may be due to insertion effects, and variation among different genotypes (whether transgenic or wild‐type) imparts a greater change in response than transgene presence.     

Characterization of a type of β‐bend ribbon spiral generated by the repeating (Xaa–Yaa–Aib–Pro) motif: The solution structure of harzianin HC IX,a 14‐residue peptaibol forming voltage‐dependent ion channels

The three‐dimensional solution structure of harzianin HC IX, a peptaibol antibiotic isolated from the fungus Trichoderma harzianum, was determined using CD, homonuclear, and heteronuclear two‐dimensional nmr spectroscopy combined with molecular modeling. This 14‐residue peptide, Ac Aib¹ Asn² Leu³ Aib⁴ Pro⁵ Ala⁶ Ile⁷ Aib⁸ Pro⁹ Iva¹⁰ Leu¹¹ Aib¹² Pro¹³ Leuol¹⁴ (Aib, α‐aminoisobutyric acid; Iva, isovaline; Leuol, leucinol), is a main representative of a short‐sequence peptaibol class characterized by an acetylated N‐terminus, a C‐terminal amino alcohol, and the presence of three Aib‐L ‐Pro motifs at positions 4–5, 8–9, and 12–13, separated by two dipeptide units. In spite of a lower number of residues, compared to the 18/20‐residue peptaibols such as alamethicin, harzianin HC IX exhibits remarkable membrane‐perturbing properties. It interacts with phospholipid bilayers, increasing their permeability and forming voltage‐gated ion channels through a mechanism slightly differing from that proposed for alamethicin. Sequence‐specific ¹H‐ and ¹³C‐nmr assignments and conformational nmr parameters (³J_NHCαH coupling constants, quantitative nuclear Overhauser enhancement data, temperature coefficients of amide and carbonyl groups, NH–ND exchange rates) were obtained in methanol solution. Sixty structures were calculated based on 98 interproton distance restraints and 6 Φ dihedral angle restraints, using high temperature restrained molecular dynamics and energy minimization. Thirty‐seven out of the sixty generated structures were consistent with the nmr data and were convergent. The peptide backbone consists in a ribbon of overlapping β‐turns twisted into a continuous spiral from Asn² to Leuol¹⁴ and forming a 26 Å long helix‐like structure. This structure is slightly amphipathic, with the three Aib–Pro motifs aligned on the less hydrophobic face of the spiral where the Asn² side chain is also present, while the more hydrophobic bulky side chains of leucines, isoleucine, isovaline, and leucinol are located on the concave side. The repetitive (Xaa–Yaa–Aib–Pro) tetrapeptide subunit, making up the peptide sequence, is characterized by four sets of (Φ,Ψ) torsional angles, with the following mean values: Φ_i = −90°, Ψ_i = −27°; Φ_i+1 = −98°, Ψ_i+1 = −17°; Φ_i+2 = −49°, Ψ_i+2 = −50°; Φ_i+3 = −78°, Ψ_i+3 = +3°. We term this particular structure, specifically occurring in the case of (Xaa–Yaa–Aib–Pro)_n sequences, the (Xaa–Yaa–Aib–Pro)‐β‐bend ribbon spiral. It is stabilized by 4 → 1 intramolecular hydrogen bonds and differs from both the canonical 3₁₀‐helix made of a succession of type III β‐turns and from the β‐bend ribbon spiral that has been described in the case of (Aib–Pro)n peptide segments. © 1999 John Wiley & Sons, Inc. Biopoly 50: 71–85, 1999     

Functional characteristics of green alga Scenedesmus obliquus (Chlorophyceae): 276–6 wild type and its two photosystems deficient mutants cultured under photoautotrophic,mixotrophic and heterotrophic conditions

Functional features of Scenedesmus obliquus: wild type 276–6 strain (WT) and its two mutants reported as photosystem I‐deficient (mutant 56.80) and photosystem II‐deficient (mutant 57.80) were characterized. Algae were cultured aseptically under continuous light or in darkness on mineral bold basal medium (BBM), yeast extract‐enriched BBM and yeast extract to evaluate the physiology of algal cells under photoautotrophic, mixotrophic and heterotrophic conditions. Growth, superoxide dismutase activity and photosynthetic parameters, including polyphasic fluorescence rise during the first seconds of chlorophyll a illumination (OJIP), were analyzed to find relationships between the photosynthetic/respiratory activity of the cells, occurrence of oxidative stress and trophic conditions applied to PSs‐deficient algae. Despite the highest superoxide dismutase activity, indicating the presence of oxidative stress, mixotrophic conditions appeared to be optimal for S. obliquus WT and mutant strains kept in non‐aerated cultures. OJIP analysis indicated that in mutant 56.80 part of photosystem (PS) I was functional and in mutant 57.80 residual PS II activity was found.     

Wild type and mutants of the HET‐s(218–289) prion show different flexibility at fibrillar ends: A simulation study

The C‐terminal segment (residues 218–289) of the HET‐s protein of the filamentous fungus Podosporina anserina is a prion‐forming domain. The structural model of the HET‐s(218–289) amyloid fibril based on solid‐state nuclear magnetic resonance (NMR) restraints shows a β solenoid topology which is comprised of a β‐sheet core and interconnecting loops. For the single‐point mutants Phe286Ala and Trp287Ala, slower aggregation rates in vitro and loss of prionic infectivity have been reported recently. Here we have used molecular dynamics to compare the flexibility of the mutants and wild type. The simulations, initiated from a trimeric aggregate extracted from the NMR structural model, show structural stability on a 100‐ns time scale for wild type and mutants. Analysis of the fluctuations along the simulations reveals that the mutants are less flexible than the wild type in the C‐terminal segment at only one of the two external monomers. Analysis of interaction energy and buried accessible surface indicates that residue Phe286 in particular is stabilized in the Trp287Ala mutant. The simulation results provide an atomistic explanation of the suggestion (based on indirect experimental evidence) that flexibility at the protofibril end(s) is required for fibril elongation. Moreover, they provide further evidence that the growth of the HET‐s amyloid fibril is directional. Proteins 2014; 82:399–404. © 2013 Wiley Periodicals, Inc.     

Structural and luminescence properties of Y2‐xGeMoO8:REx (RE = Eu,Tb) phosphors

Y_2‐xGeMoO₈:RE_x (RE = Eu, Tb) phosphors were synthesized using a facile sol–gel method. The morphology and structure of the phosphors were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD); while their luminescent properties were investigated by photoluminescence (PL) spectrometry. Our results reveal that all of these Y_2‐xGeMoO₈:RE_x (RE = Eu, Tb) phosphors adopted the tetragonal phase, belonging to Scheelite (CaWO₄) structure. The obtained YGeMoO₈:Eu phosphors exhibit a strong emission in the red light range which can be assigned to the ⁵D₀ → ⁷F₂ transition of Eu³⁺ when it is excited at 459 nm. Under 392 and 489 nm excitation, the YGeMoO₈:Tb phosphors present predominant green emission (⁵D₄ → ⁷F₅) at 540 nm. The highest emission of the phosphors can be achieved by adjusting the doping concentration to be 0.25 for Eu³⁺ and 0.15 for Tb³⁺, respectively. The promising luminescence properties of these materials indicate that they can be potentially applied to white‐light‐emitting diodes. Copyright © 2013 John Wiley & Sons, Ltd.     

Time to abandon the loss of dispersal ability hypothesis in island plants: A comment on García‐Verdugo,Mairal, Monroy,Sajeva and Caujapé‐Castells (2017)

García‐Verdugo et al. (2017) recently tested the loss of dispersal ability hypothesis in a wind‐dispersed shrub from Southern Europe. Although the hypothesis has guided research for over 150 years, García‐Verdugo et al. (2017) results failed to substantiate its central prediction—the loss of seed dispersal potential in island populations. Here, I highlight several additional limitations of the hypothesis. First, García‐Verdugo et al. (2017) results are not unusual. Empirical support for the hypothesis is equivocal. Second, when reduced dispersal potential is documented, it may often evolve as a passive by‐product of selection for large seeds, for reasons that are wholly unrelated to their dispersal. Third, the hypothesis does not readily apply to all plant dispersal modes, particularly plants that produce fleshy fruits. These issues advocate a fresh approach to the study of how selection shapes the evolution of dispersal potential on islands.     

Conventional and microwave‐assisted SPPS approach: a comparative synthesis of PTHrP(1–34)NH2

Attracted by the possibility to optimize time and yield of the synthesis of difficult peptide sequences by MW irradiation, we compared Fmoc/tBu MW‐assisted SPPS of 1–34 N‐terminal fragment of parathyroid hormone‐related peptide (PTHrP) with its conventional SPPS carried out at RT. MWs were applied in both coupling and deprotection steps of SPPS protocol. During the stepwise elongation of the resin‐bound peptide, monitoring was conducted by performing MW‐assisted mini‐cleavages and analyzing them by UPLC‐ESI‐MS. Identification of some deletion sequences was helpful to recognize critical couplings and as such helped to guide the introduction of MW irradiations to these stages. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.     

Folding and membrane insertion of amyloid‐beta (25–35) peptide and its mutants: Implications for aggregation and neurotoxicity

The mechanisms of interfacial folding and membrane insertion of the Alzheimer's amyloid‐β fragment Aβ(25–35) and its less toxic mutant, N27A‐Aβ(25–35) and more toxic mutant, M35A‐Aβ(25–35), are investigated using replica–exchange molecular dynamics in an implicit water‐membrane environment. This study simulates the processes of interfacial folding and membrane insertion in a spontaneous fashion to identify their general mechanisms. Aβ(25–35) and N27A‐Aβ(25–35) peptides share similar mechanisms: the peptides are first located in the membrane hydrophilic region where their C‐terminal residues form helical structures. The peptides attempt to insert themselves into the membrane hydrophobic region using the C‐terminal or central hydrophobic residues. A small portion of peptides can successfully enter the membrane's hydrophobic core, led by their C‐terminal residues, through the formation of continuous helical structures. No detectable amount of M35A‐Aβ(25–35) peptides appeared to enter the membrane's hydrophobic core. The three studied peptides share a similar helical structure for their C‐terminal five residues, and these residues mainly buried within the membrane's hydrophobic region. In contrast, their N‐terminal properties are markedly different. With respect to the Aβ(25–35), the N27A‐Aβ(25–35) forms a more structured helix and is buried deeper within the membrane, which may result in a lower degree of aggregation and a lower neurotoxicity; in contrast, the less structured and more water‐exposed M35A‐Aβ(25–35) is prone to aggregation and has a higher neurotoxicity. Understanding the mechanisms of Aβ peptide interfacial folding and membrane insertion will provide new insights into the mechanisms of neurodegradation and may give structure‐based clues for rational drug design preventing amyloid associated diseases. Proteins 2010. © 2010 Wiley‐Liss, Inc.     

MMP‐3 (–1171 5A/6A; Lys45Glu) variants affect serum levels of matrix metalloproteinase (MMP)‐3 and correlate with severity of COPD: A study of MMP‐3, MMP‐7 and MMP‐12 in a Tunisian population

Background

The present study aimed to examine the role of matrix metalloproteinase (MMP)‐3 [(–1171) 5A/6A; Lys45Glu (A/G)], MMP‐7 [(–181) A/G] and MMP‐12 [(–82) A/G; Asn357Ser (A/G)] variants in the development and severity of chronic obstructive pulmonary disease (COPD) in Tunisians.

Methods

Plethysmography was performed in all participants to measure forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC parameters. Genotyping of MMP‐3, MMP‐7 and MMP‐12 polymorphisms was carried out in 138 patients with COPD and 216 healthy controls using a polymerase chain reaction–restriction fragment length polymorphism. Serum levels of MMPs and cytokines (interleukin‐6, tumor necrosis factor‐α) were determined by an enzyme‐linked immunosorbent assay.

Results

No significant correlations were observed between genetic variations in MMP‐3, MMP‐7 and MMP‐12 and the risk of development of COPD. Additionally, no impact of MMP‐7 (–181) A/G and MMP‐12 [(–82) A/G; Asn357Ser (A/G)] polymorphisms was observed on the respective protein levels and clinical parameters of the disease. Interestingly, both MMP‐3 (–1171) 5A/6A and Lys45Glu (A/G) variants were associated with respiratory function, as well as with serum levels of MMP‐3 in COPD patients. A relationship was found between the (–1171) 6A and 45Glu (G) alleles of the MMP‐3 gene and enhanced airflow limitation among COPD patients. Additionally, carriers of the 6A6A and 45 GG genotypes present higher MMP‐3 levels than noncarriers.

Conclusions

MMP‐3 (–1171) 5A/6A and Lys45Glu (A/G) polymorphisms were associated with the decline of lung function among COPD patients. These results could be linked to the upregulation of MMP‐3 in serum from COPD patients carrying the (–1171) 6A and 45 G homozygous genotypes.     

Nitrogen and carbon contents and δ15N and δ13C signatures in six bryophyte species: assessment of long‐term deposition changes (1980–2010) in Spanish beech forests

In this study we used recent (2010) and herbarium material (1980) of six bryophyte species to assess long‐term atmospheric deposition in natural forested areas in northern Spain. For this purpose, tissue nitrogen and carbon content, as well as δ¹³C and δ¹⁵N signatures of samples of Hypnum cupressiforme, Polytrichastrum formosum, Leucobryum juniperoideum, Rhytidiadelphus loreus, Homalothecium lutescens and Diplophyllum albicans were analysed and comparisons made between years and species. In addition, the usefulness of each of the six species was evaluated. The range of values observed was similar to that in other studies carried out in rural areas. Significantly lower values were found in 2010 for N (H. cupressiforme), δ¹⁵N (R. loreus and D. albicans), C (R. loreus) and δ¹³C (all except L. juniperoideum). Our natural areas are thus now less influenced by atmospheric pollutants than they were, most probably due to changes in some traditional local activities. Differences were observed between species for all the four parameters studied, so different species must not be analysed together. Finally, R. loreus and H. lutescens seem to be good bioindicators, sensitive even with a few samples, although further studies are needed to corroborate their usefulness.     

Species diversity of the deep‐water gulper sharks (Squaliformes: Centrophoridae: Centrophorus) in North Atlantic waters – current status and taxonomic issues

The gulper sharks (genus Centrophorus) are a group of deep‐water benthopelagic sharks with a worldwide distribution. The alpha taxonomy of the group has historically been problematic and the number of species included in the genus has varied considerably over the years and is still under debate. Gulper sharks are routinely caught in mid‐ and deep‐water fisheries worldwide and some have shown a considerable decline in abundance in the last few decades. Clear and consistent species discrimination of Centrophorus is essential for an efficient and sustainable management of these fisheries resources. Our study used molecular cytochrome oxidase subunit I (COI) and 16S ribosomal RNA gene sequences and morphometric data to re‐evaluate the diversity of Centrophorus in North Atlantic waters, including the Gulf of Mexico, the Caribbean, and the Mediterranean Seas. Molecular data separated North Atlantic Centrophorus into five well‐supported groups whereas morphometric data separated these same five groups and suggested three additional groups for which no molecular data were available. Four of the five groups identified in the North Atlantic also occur in the Indian and/or Pacific Oceans, thus extending the reported range of some species considerably. A species identification key for North Atlantic Centrophorus is provided based on our findings. © 2014 The Linnean Society of London     

Mitochondrial phylogeography and subspecies of the wide‐ranging sub‐Saharan leopard tortoise Stigmochelys pardalis (Testudines: Testudinidae) – a case study for the pitfalls of pseudogenes and GenBank sequences

The leopard tortoise (Stigmochelys pardalis) is the most widely distributed sub‐Saharan tortoise species, with a range extending from the Horn of Africa all over eastern Africa to the Republic of South Africa, Namibia and southernmost Angola. Using 1938 bp of mitochondrial DNA (cyt b gene, partial ND4 gene plus adjacent tRNA genes) from a nearly range‐wide sampling, we examined its phylogeographic structure and compared our findings with previously published GenBank sequences. We identified seven major clades that are largely parapatrically distributed. A few records of distinct haplotypes at the same locality or in close proximity could be the result of translocation of tortoises by man. The greatest diversity occurs in the south of the species’ range, with five out of the seven clades. Testing for isolation‐by‐distance suggests that the observed phylogeographic structure is the result of restricted geographical gene flow and not of historical vicariance. This is in sharp contrast to wide‐ranging thermophilic reptiles from the western Palaearctic, whose phylogeographic structure was significantly shaped by Pleistocene range interruptions, but also by earlier dispersal and vicariant events. Most cyt b sequences of S. pardalis from GenBank turned out to be nuclear pseudogenes, or to be of chimerical origin from such pseudogenes and authentic mitochondrial sequences, which argues for caution regarding uncritical usage of GenBank sequences. The recent revalidation of the two subspecies of S. pardalis was based on such a chimerical sequence that was erroneously identified with the subspecies S. p. babcocki. Furthermore, according to our data, the distribution of mitochondrial clades does match neither the traditional subspecies ranges nor the pronounced geographical size variation of leopard tortoises. We conclude that there is no rationale for recognizing subspecies within S. pardalis.     

Signals of range expansions and contractions of vascular plants in the high Alps: observations (1994–2004) at the GLORIA* master site Schrankogel,Tyrol, Austria

High mountain ecosystems are defined by low temperatures and are therefore considered to react sensitively to climate warming. Responding to observed changes in plant species richness on high peaks of the European Alps, an extensive setup of 1 m × 1 m permanent plots was established at the alpine‐nival ecotone (between 2900 and 3450 m) on Mount Schrankogel, a GLORIA master site in the central Tyrolean Alps, Austria, in 1994. Recording was repeated in a representative selection of 362 quadrats in 2004. Ten years after the first recording, we observed an average change in vascular plant species richness from 11.4 to 12.7 species per plot, an increase of 11.8% (or of at least 10.6% at a 95% confidence level). The increase in species richness involved 23 species (about 43% of all taxa found at the ecotone), comprising both alpine and nival species and was pronouncedly higher in plots with subnival/nival vegetation than in plots with alpine grassland vegetation. Only three species showed a decrease in plot occupancy: one was an annual species, one was rare, and one a common nival plant that decreased in one part of the area but increased in the uppermost part. Species cover changed in relation to altitudinal preferences of species, showing significant declines of all subnival to nival plants, whereas alpine pioneer species increased in cover. Recent climate warming in the Alps, which has been twice as high as the global average, is considered to be the primary driver of the observed differential changes in species cover. Our results indicate an ongoing range contraction of subnival to nival species at their rear (i.e. lower) edge and a concurrent expansion of alpine pioneer species at their leading edge. Although this was expected from predictive distribution models and different temperature‐related habitat preferences of alpine and nival species, we provide first evidence on – most likely – warming‐induced species declines in the high European Alps. The projected acceleration of climate warming raises concerns that this phenomenon could become the major threat to biodiversity in high mountains.     

Effects of fermented aloe vera mixed diet on larval growth of Protaetia brevitarsis seulensis (Kolbe) (coleopteran:Cetoniidae) and protective effects of its extract against CCl4‐induced hepatotoxicity in Sprague–Dawley rats

The present study was conducted to evaluate the efficacy of fermented aloe vera mixed diet on larval growth of Protaetia brevitarsis seulensis (Kolbe) (coleopteran: Cetoniidae) and protective effects of extract of larvae of P. brevitarsis seulensis fed fermented aloe vera mixed diet against Carbon tetrachloride (CCl₄)‐induced hepatotoxicity in Sprague–Dawley rats. To determine whether different diets can affect the larval growth of P. brevitarsis seulensis, six different diets were investigated in the experiment, and the results exhibited that 15% fermented aloe vera with 85% fermented oakwood sawdust was the best diet for larval growth of this insect, followed by 9% fermented aloe vera with 91% fermented oakwood sawdust. Adult male Sprague–Dawley rats (n= 30) were separated into five groups of six each, as follows: control group; CCl₄ group; CCl₄ plus larval extract group (without fermented aloe vera); CCl₄ plus 9% and 15% larval extract groups (with fermented aloe vera). All extract groups were fed with 30 mg/kg extracts of fermented oakwood sawdust only and fermented oakwood sawdust plus 9% and 15% fermented aloe vera, respectively, once every consecutive day, with administration of CCl₄ (1.5 mL/kg, 20% CCl₄ in olive oil) twice a week for 3 weeks. Administration of CCl₄ increased the serum alanine aminotransferase, aspartate aminotranseferase and thiobarbituric acid reactive substance levels in rats and reduced levels of glutathione in the liver. Treatment with extract of larval‐fed fermented aloe vera mixed diet significantly alleviated these changes to nearly normal levels. The histopathological changes induced by CCl₄ were also significantly attenuated by extract of larval‐fed fermented aloe vera mixed diet treatment. The results suggest that the beneficial effect of fermented aloe vera mixed diet on larval growth may be to stimulate the larval life cycle, and 15% larval‐fed fermented aloe vera mixed diet exhibits potent hepatoprotective effects on CCl₄‐induced liver injury in rats, likely due to increased glutathione contents and the inhibition of lipid peroxidation.     

Porcine proximal tubular cells (LLC‐PK1) are able to tolerate high levels of lithium chloride in vitro: assessment of the influence of 1–20 mM LiCl on cell death and alterations in cell biology and biochemistry

Lithium, a prophylactic drug for the treatment of bipolar disorder, is prescribed with caution due to its side effects, including renal damage. In this study porcine LLC‐PK₁ renal tubular cells were used to establish the direct toxicity of lithium on proximal cells and gain insights into the molecular mechanisms involved. In the presence of LiCl, cell proliferation exhibited insignificant decreases in a concentration‐dependent manner, but once confluent, constant cell numbers were observed. Cell cycle studies indicated a small dose‐dependant accumulation of cells in the G₂/M stage after 24 h, as well as an increase in cells in the G₀/G₁ phase after treatment with 1–10 mM LiCl, but not at 20 mM LiCl. No evidence of apoptosis was observed based on cell morphology or DNA fragmentation studies, or evidence of protein expression changes for Bax, Bcl‐2, and p53 proteins using immunocytochemistry. In addition caspases 3, 8 and 9 activity remained unaltered between control and lithium‐treated cultures. To conclude, exposure to high concentrations of lithium did not result in overt toxic effects to LLC‐PK₁ renal cells, although LiCl did alter some aspects of cell behaviour, which could potentially influence function over time.