Intracellular positioning of isoforms explains an unusually large adenylate kinase gene family in the parasite Trypanosoma brucei

Adenylate kinases occur classically as cytoplasmic and mitochondrial enzymes, but the expression of seven adenylate kinases in the flagellated protozoan parasite Trypanosoma brucei (order, Kinetoplastida; family, Trypanosomatidae) easily exceeds the number of isoforms previously observed within a single cell and raises questions as to their location and function. We show that a requirement to target adenylate kinase into glycosomes, which are unique kinetoplastid-specific microbodies of the peroxisome class in which many reactions of carbohydrate metabolism are compartmentalized, and two different flagellar structures as well as cytoplasm and mitochondrion explains the expansion of this gene family in trypanosomes. The three isoforms that are selectively built into either the flagellar axoneme or the extra-axonemal paraflagellar rod, which is essential for motility, all contain long N-terminal extensions. Biochemical analysis of the only short form trypanosome adenylate kinase revealed that this enzyme catalyzes phosphotransfer of gamma-phosphate from ATP to AMP, CMP, and UMP acceptors; its high activity and specificity toward CMP is likely to reflect an adaptation to very low intracellular cytidine nucleotide pools. Analysis of some of the phosphotransfer network using RNA interference suggests considerable complexity within the homeostasis of cellular energetics. The anchoring of specific adenylate kinases within two distinct flagellar structures provides a paradigm for metabolic organization and efficiency in other flagellates.     

Sterically locked synthetic bilin derivatives and phytochrome Agp1 from Agrobacterium tumefaciens form photoinsensitive Pr- and Pfr-like adducts

Phytochrome photoreceptors undergo reversible photoconversion between the red-absorbing form, Pr, and the far-red-absorbing form, Pfr. The first step in the conversion from Pr to Pfr is a Z to E isomerization around the C15=C16 double bond of the bilin chromophore. We prepared four synthetic biliverdin (BV) derivatives in which rings C and D are sterically locked by cyclizing with an additional carbon chain. In these chromophores, which are termed 15Za, 15Zs, 15Ea, and 15Es, the C15=C16 double bond is in either the Z or E configuration and the C14-C15 single bond in either the syn or anti conformation. The chromophores were assembled with Agrobacterium phytochrome Agp1, which incorporates BV as natural chromophore. All locked BV derivatives bound covalently to the protein and formed adducts with characteristic spectral properties. The 15Za adduct was spectrally similar to the Pr form and the 15Ea adduct similar to the Pfr form of the BV adduct. Thus, the chromophore of Agp1 adopts a C15=C16 Z configuration and a C14-C15 anti conformation in the Pr form and a C15=C16 E configuration and a C14-C15 anti conformation in the Pfr form. Both the 15Zs and the 15Es adducts absorbed only in the blue region of the visible spectra. All chromophore adducts were analyzed by size exclusion chromatography and histidine kinase activity to probe for protein conformation. In either case, the 15Za adduct behaved like the Pr and the 15Ea adduct like the Pfr form of Agp1. Replacing the natural chromophore by a locked 15Ea derivative can thus bring phytochrome holoprotein in the Pfr form in darkness. In this way, physiological action of Pfr can be studied in vivo and separated from Pr/Pfr cycling and other light effects.     

Hydroxylation of progesterone by some<Emphasis Type="Italic">Trichoderma</Emphasis> species

Thirty-three isolates belonging to six species of the genus Trichoderma were tested for the ability to hydroxylate progesterone to 11alpha-, 11beta-, 11alpha,17alpha- and 6beta, 17alpha-derivatives, and epicortisol. T. aureoviride, T. harzianum, T. polysporum and T. pseudokoningii produced 11alpha-hydroxyprogesterone. T. harzianum and T. hamatum can form only the 11beta-isomer. T. koningii and T. hamatum produced 11alpha-, 11beta-, 11alpha,17alpha- and 6beta,11alpha-hydroxy derivatives. 11alpha, 11beta, 6beta,11alpha- and 11alpha,17alpha-hydroxyprogesterones and epicortisol are produced by T. aureoviride and T. pseudokoningii. Cortisol was produced only when the medium was fortified by 10 g/L peptone. This is the first record of conversion of progesterone to mono-, di- and trihydroxyprogesterones by these Trichoderma species.     

Alterations in blood pressure due to chronic exposure to natural sour gas leakage containing sulfur compounds

In order to show the alteration of blood pressure in subjects chronically exposed to natural gas containing sulfur compounds, the present study was done. The blood pressure of 94 (43 males, 51 females) of healthy individuals living in the polluted area of Masjid-i-Sulaiman (Khozestan province, southwest of Iran) was measured. The non-parametric Sign test was applied in order to detect differences between the study subjects and the normal mean values according to the sex and age of subjects. Statistical analysis showed that the systolic blood pressure significantly decreased (Z=-2.74; P=0.0031) while the diastolic blood pressure (Z=+2.11; P=0.0174) and heart rate (Z=+3.62; P<0.001) significantly increased in individuals living in the contaminated areas compared with those of normal mean values. The systolic and diastolic blood pressure decreased and increased, respectively, in individuals chronically exposed to natural sour gas containing sulfur compounds.     

Effects of ocean acidification on the growth and biochemical composition of a green alga (Ulva fasciata) and its associated microbiota

In marine ecosystems, fluctuations in surface-seawater carbon dioxide (CO₂), significantly influence the whole metabolism of marine algae, especially during the early stages of macroalgal development. In this study, the response of the green alga Ulva fasciata for elevating ocean acidification was investigated using four levels of pCO₂ ~ 280, 550, 750 and 1050 µatm. Maximum growth rate (6.6% day⁻¹), protein (32.43 %DW) and pigment (2.9 mg/g) accumulation were observed at pCO₂-550 with an increase of ~2-fold compared to control. On the other hand, lipid and carbohydrate contents recorded their maximum production (4.23 and 46.96 %DW, respectively) at pCO₂-750 while control showed 3.70 and 42.37 %DW, respectively. SDS-PAGE showed the presence of unique bands in response to pCO_2, especially at 550 µatm. Dominant associated bacteria was shifted from Halomonas hydrothermalis of control to Vibrio toranzoniae at pCO₂-1050. These findings suggest that ocean acidification at 550 µatm might impose noticeable effects on growth, protein, pigments, and protein profile of U. fasciata, which could be a good source for fish farming. While, pCO₂-750 was recommended for energetic purpose, due to its high lipid and carbohydrate contents.     

Vibrational characteristics of bone fracture and fracture repair: application to excised rat femur

BACKGROUND: The vibrational characteristics of any object are directly dependent on the physical properties of that object. Therefore, changing the physical properties of an object will cause the object to adopt changed natural frequencies. A fracture in a bone results in the loss of mechanical stability of the bone. This change in mechanical properties of a bone should result in a change of the resonant frequencies of that bone. A vibrational method for bone evaluation has been introduced. METHOD OF APPROACH: This method uses the radiation force of focused amplitude-modulated ultrasound to exert a vibrating force directly, and remotely, on a bone. The vibration frequency is varied in the range of interest to induce resonances in the bone. The resulting bone motion is recorded and the resonance frequencies are determined. Experiments are conducted on excised rat femurs and resonance frequencies of intact, fractured, and bonded (simulating healed) bones are measured. RESULTS: The experiments demonstrate that changes in the resonance frequency are indicative of bone fracture and healing, i.e., the fractured bone exhibits a lower resonance frequency than the intact bone, and the resonance frequency of the bonded bone approaches that of the intact bone. CONCLUSION: It is concluded that the proposed radiation force method may be used as a remote and noninvasive tool for monitoring bone fracture and healing process, and the use of focused ultrasound enables one to selectively evaluate individual bones.     

Clinical response to chemotherapy in locally advanced breast cancer was not associated with several polymorphisms in detoxification enzymes and DNA repair genes

The main aim of the present study was to investigate the association between several genetic polymorphisms (in glutathione S-transferase members and DNA repair genes) and clinical response to chemotherapy in locally advanced breast cancer. A sequential series of 101 patients were prospectively included in this study. Clinical assessment of treatment was accomplished by comparing initial tumor size with preoperative tumor size using revised RECIST guideline (version 1.1). Clinical response was regarded as a response or no response. There was no difference between non-responders and responders for the prevalence of genotypes of the study polymorphisms.     

Activation of the pyrin inflammasome by intracellular Burkholderia cenocepacia

Burkholderia cenocepacia is an opportunistic pathogen that causes chronic infection and induces progressive respiratory inflammation in cystic fibrosis patients. Recognition of bacteria by mononuclear cells generally results in the activation of caspase-1 and processing of IL-1β, a major proinflammatory cytokine. In this study, we report that human pyrin is required to detect intracellular B. cenocepacia leading to IL-1β processing and release. This inflammatory response involves the host adapter molecule ASC and the bacterial type VI secretion system (T6SS). Human monocytes and THP-1 cells stably expressing either small interfering RNA against pyrin or YFP-pyrin and ASC (YFP-ASC) were infected with B. cenocepacia and analyzed for inflammasome activation. B. cenocepacia efficiently activates the inflammasome and IL-1β release in monocytes and THP-1. Suppression of pyrin levels in monocytes and THP-1 cells reduced caspase-1 activation and IL-1β release in response to B. cenocepacia challenge. In contrast, overexpression of pyrin or ASC induced a robust IL-1β response to B. cenocepacia, which correlated with enhanced host cell death. Inflammasome activation was significantly reduced in cells infected with T6SS-defective mutants of B. cenocepacia, suggesting that the inflammatory reaction is likely induced by an as yet uncharacterized effector(s) of the T6SS. Together, we show for the first time, to our knowledge, that in human mononuclear cells infected with B. cenocepacia, pyrin associates with caspase-1 and ASC forming an inflammasome that upregulates mononuclear cell IL-1β processing and release.     

Impact of DNA repair genes polymorphism (XPD and XRCC1) on the risk of breast cancer in Egyptian female patients

The genes involved in DNA repair system play a crucial role in the protection against mutations. It has been hypothesized that functional deficiencies in highly conserved DNA repair processes resulting from polymorphic variation may increase genetic susceptibility to breast cancer (BC). The aim of the present study was to evaluate the association of genetic polymorphisms in 2 DNA repair genes, XPD (Asp312Asn) and XRCC1 (A399G), with BC susceptibility. We further investigated the potential combined effect of these DNA repair variants on BC risk. Both XPD (xeroderma pigmentosum group D) and XRCC1 (X-ray repair cross-complementing group 1) polymorphisms were characterized in 100 BC Egyptian females and 100 healthy women who had no history of any malignancy by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) method and PCR with confronting two-pair primers (PCR-CTPP), using DNA from peripheral blood in a case control study. Our results revealed that the frequencies of AA genotype of XPD codon 312 polymorphism were significantly higher in the BC patients than in the normal individuals (P ≤ 0.003), and did not observe any association between the XRCC1 Arg399Gln polymorphism and risk of developing BC. Also, no association between both XPD Asp312Asn and XRCC1 A399G polymorphisms and the clinical characteristics of disease. Finally, the combination of AA(XPD) + AG(XRCC1) were significantly associated with BC risk. Our results suggested that, XPD gene is an important candidate gene for susceptibility to BC. Also, gene–gene interaction between XPD(AA) + XRCC1(AG) polymorphism may be associated with increased risk of BC in Egyptian women.