AGRONOMY

Comparison of five allopatric fruit fly parasitoid populations (Psyttalia species) (Hymenoptera: Braconidae) from coffee fields using morphometric and molecular methods

Billah, M. K.; Kimani-Njogu, S. W.; Wharton, R. A.; Woolley, J. B.; Masiga, D.

Morphometric studies of five allopatric parasitoid populations (genus Psyttalia Walker) from coffee plantations in Cameroon (Nkolbisson), Ghana (Tafo) and Kenya (Rurima, Ruiru and Shimba Hills) and one non-coffee population (from Muhaka, Kenya) were compared with individuals of Psyttalia concolor (Szepligeti), a species released in several biological control programmes in the Mediterranean Region since the 20th Century. Analyses of wing vein measurements showed the second submarginal cell of the fore wing and its adjoining veins had the heaviest principal component weights and served as the main contributing variables in the diagnostic differentiation of the populations. Two populations (Rurima and Ruiru) were found to be the closest to each other and with the strongest phenetic affinity toward P. concolor (and forming one cluster). Populations from Shimba Hills (of unknown identity), Nkolbisson (P. perproximus (Silvestri)) and Tafo formed a second cluster and were separated from P. concolor. Comparison using amplified fragment length polymorphism (AFLP) also showed the Shimba, Nkolbisson and Tafo populations forming a cluster in a dendrogram generated from their genetic distances, with the Shimba and Tafo populations placed as the most closely related species. Based on consistent morphological similarities, morphometric and ecological data coupled with the genetic evidence from AFLP data, the Shimba population is suggested as belonging to the P. perproximus group and, thus, represents a new occurrence record in Kenya. Our results also support earlier conclusion from cross mating data that populations from Rurima and Ruiru belong to the Psyttalia concolor species-group.

Source :  Bull.Entomol.Res. 2008 vol.98 (1), pp 63 - 75

Epicarp characterization of coffee fruits by atomic force microscopy

Cardona, Y. P.; Oliveros, C. E.; Arias, D. F.; Alvarez, F.; Devia, A.

The superficial characterization of epicarp of the coffee fruits was made in two states of development: mature and green. The roughness of the area, and also the line for the parameters of roughness average (Ra) and quadratic root average of the roughness (Rq), were found by means of atomic force microscopy (AFM). In addition, the densities and dimensions of the coffee cells were found. The Ra range of the
mature fruit was found to be between 0.03 and 0.19mum, and for the green fruit it was between 0.23 and 0.38mum. The Rq range of the mature fruit was found to be between 0.05 and 0.24mum, and for the green fruit it was between 0.29 and 0.49mum. These values delimit ranges of roughness for each state of development analyzed, and there is a difference among them without appearing interpolation of the data. It was determined that the cells have ellipsoidal form with an average area of 194.62mum2, and the density average is 4.206cell/mm2.

Source : J Food Eng 2008 vol.86 (2), pp 167 - 171

BIOCHEMISTRY / BIOTECHNOLOGY

The storage of green coffee (Coffea arabica): decrease of viability and changes of potential aroma precursors

Selmar, D.; Bytof, G.; Knopp, S. E.

When green coffee is stored for a prolonged time the coffee quality decreases distinctively. Apart from well-known 'off-notes' that arise from undesired oxidations of lipids, a typical 'flattening' of the cup quality is detectable. In order to elucidate the biological causes for this phenomenon, differentially processed coffees (wet, dry, semi-dry processing), were stored under standard conditions for 2 years and analysed comprehensively. METHODS: Wet-processed coffee was stored either as parchment coffee, where the endocarp remained around the beans or as hulled beans. Viability of coffee seeds was estimated using the tetrazolium-test of seed viability. Changes in concentration of free amino acids and soluble carbohydrates were analysed by HPLC. KEY RESULTS: Whereas all other coffees lost viability within the first 6 months of storage, coffee beans stored within the parchment remained viable for >1 year. Glucose and fructose decreased slightly in the course of storage and glutamine content declined significantly. However, the changes observed in sugar and amino acid content were not correlated with the viability of the coffee beans. Consequently, neither typical metabolic reactions occurring within living cells nor characteristic post-mortem reactions could be responsible for the observed changes. As a result of post-mortem reactions in re-imbibed seeds, a characteristic bluish-green colour developed, putatively due to the oxidation of chlorogenic acids and subsequent reactions with primary amino compounds. This coloration might be an appropriate marker to substantiate if coffee seeds had been stored for an expanded time and putative quality losses were not relevant so far.

CONCLUSIONS: It is suggested that loss of viability is relevant for the aroma flattening. As neither metabolic nor post-mortem reactions were responsible for the observed changes, it is concluded that Maillard reactions that occur during storage might be the cause of the decrease in potential aroma precursors.

Source : Ann Bot (Lond) 2008 vol.101 (1), pp 31 - 38

CHEMISTRY / SENSORICS

Determination of caffeine and sympathomimetic alkaloids in weight loss supplements by high-performance liquid chromatography

Evans, R. L.; Siitonen, P. H.

Reversed-phase high-performance liquid chromatography utilizing photodiode array detection is used for the simultaneous determination of caffeine and nine alkaloids from Citrus aurantium (CA) and ephedra (EA) contained in dietary weight loss products. Since the Food and Drug Administration (FDA) ban of EA, manufacturers have substituted CA in their weight loss formulations, usually combined with high levels of caffeine. The alkaloids contained in CA have some physiological effects similar to those of the EA alkaloids and are, therefore, cause for concern. Caffeine has been shown to potentiate the toxicity of the EA alkaloids. Recently, a federal judge overturned the absolute ban and allowed marketing of low levels (< 10 mg/day) of total EA alkaloids. To support an absolute ban, the FDA is now compelled to perform dose-dependent toxicology studies to determine the toxic dose(s) of EA. The toxicity of the CA compounds is largely unknown, especially in combination with caffeine. The described method enables quantitation over a wide range of product formulations. Recoveries range from 91 % to 100% from a variety of fortified plant matrices.

Source :  J Chromatogr Sci  2008 vol.46 (1), pp 61 - 67

Calorimetric and spatial characterization of polymorphic transitions in caffeine using quasi-isothermal MTDSC and localized thermomechanical analysis

Manduva, R.; Kett, V. L.; Banks, S. R.; Wood, J.; Reading, M.; Craig, D. Q.

We describe a novel integrated approach to the study of polymorphic transformation that includes quasi-isothermal modulated temperature differential scanning calorimetry (QI-MTDSC) and microthermal analysis (MTA), with a view to studying the thermal, kinetic and spatial characteristics of the process. Form II and I caffeine was prepared and conventional DSC and hot stage microscopy performed. The Form II to I transition at circa 413 K was associated with a change in crystal habit to needle shaped crystals. QI-MTDSC was used to measure the heat capacity of the system as a function of temperature, while MTA was able to spatially differentiate between the two polymorphs in compressed systems. We present a novel extension of the reduced temperature method whereby we apply it for the first time to linear rising temperature data corresponding to the transition; the analysis suggests a close approximation to Arrhenius behavior. We also describe a heat transfer model that allows calculation of the thermal gradients within a hermetically sealed pan for the first time. The combined approach has therefore allowed the characterization of the thermodynamics and kinetics of the transformation process as well as spatial identification of the distribution of the transformation in compressed systems.

Source :  J Pharm Sci 2008 vol.97 (3), pp 1285 - 1300

COFFEE & HEALTH

Coffee consumption, serum gamma-glutamyltransferase and risk of type II diabetes

Bidel, S.; Silventoinen, K.; Hu, G.; Lee, D. H.; Kaprio, J.; Tuomilehto, J.

Objectives:To study the joint association of coffee consumption and serum gamma-glutamyltransferase (GGT) levels on the risk of developing type II diabetes. Design, setting and subjects:A total of 21 826 Finnish men and women who were 35-74 years of age and without any history of diabetes at baseline (years 1982, 1987, 1992 and 1997) were included in the present analyses. They were prospectively followed up for onset of type II diabetes (n=862 cases), death or until the end of the year 2002. Coffee consumption, serum GGT and other study parameters were determined at baseline using standardized measurements. Analyses were stratified by the serum GGT level classified into two classes using the 75th sex-specific percentiles as the cut point.Results:Coffee consumption was significantly and inversely associated with incident diabetes among both men and women. Serum GGT modified the association between coffee consumption and incident diabetes. Subjects in the high category of coffee consumption with the GGT level >/=75th percentile showed a significant inverse association for women, and for both sexes combined. The association was not significant in subjects with the GGT level </=75th percentile. There was a significant interaction effect of GGT and coffee consumption on risk of type II diabetes in data of women (P=0.05) and in both sexes combined (P=0.02). Conclusions:Habitual coffee consumption is associated with lower incidence of type II diabetes particularly in those with higher baseline serum GGT levels.

Source : Eur.J.Clin.Nutr. 2008 vol.62 (2), pp 178 - 185

Psychological effects of dietary components of tea: caffeine and L-theanine

Bryan, J.

This review summarizes the literature on the association between two dietary components of tea, caffeine and L-theanine, and the psychological outcomes of consumption; it also identifies areas for future research. The studies reviewed suggest that caffeinated tea, when ingested at regular intervals, may maintain alertness, focused attention, and accuracy and may modulate the more acute effects of higher doses of caffeine. These findings concur with the neurochemical effects of L-theanine on the brain. L-theanine may interact with caffeine to enhance performance in terms of attention switching and the ability to ignore distraction; this is likely to be reflective of higher-level cognitive activity and may be sensitive to the detrimental effects of overstimulation. Further research should investigate the interactive effects of caffeine, L-theanine, and task complexity, utilize a range of ecologically valid psychological outcomes, and assess the neuroprotective effects of L-theanine using epidemiological or longer-term intervention studies among individuals at risk of neurodegenerative disease.

Source : Nutr Rev 2008 vol.66 (2), pp 82-90

Interaction of caffeine with regadenoson-induced hyperemic myocardial blood flow as measured by positron emission tomography: a randomized, double-blind, placebo-controlled crossover trial

Gaemperli, O.; Schepis, T.; Koepfli, P.; Siegrist, P. T.; Fleischman, S.; Nguyen, P.; Olmsted, A.; Wang, W.; Lieu, H.; Kaufmann, P. A.

No abstract available

Source : J Am Coll Cardiol 2008 vol.51 (3),  pp 328 - 329

The effects of l-theanine, caffeine and their combination on cognition and mood

Haskell, C. F.; Kennedy, D. O.; Milne, A. L.; Wesnes, K. A.; Scholey, A. B.

l-Theanine is an amino acid found naturally in tea. Despite the common consumption of l-theanine, predominantly in combination with caffeine in the form of tea, only one study to date has examined the cognitive effects of this substance alone, and none have examined its effects when combined with caffeine. The present randomised, placebo-controlled, double-blind, balanced crossover study investigated the acute cognitive and mood effects of l-theanine (250mg), and caffeine (150mg), in isolation and in combination. Salivary caffeine levels were co-monitored. l-Theanine increased 'headache' ratings and decreased correct serial seven subtractions. Caffeine led to faster digit vigilance reaction time, improved Rapid Visual Information Processing (RVIP) accuracy and attenuated increases in self-reported 'mental fatigue'. In addition to improving RVIP accuracy and 'mental fatigue' ratings, the combination also led to faster simple reaction time, faster numeric working memory reaction time and improved sentence verification accuracy. 'Headache' and 'tired' ratings were reduced and 'alert' ratings increased. There was also a significant positive caffeinexl-theanine interaction on delayed word recognition reaction time. These results suggest that beverages containing l-theanine and caffeine may have a different pharmacological profile to those containing caffeine alone.

Source :  Biol Psychol 2008 vol.77 (2), pp 113 - 122

Induction of cancer chemopreventive enzymes by coffee is mediated by transcription factor Nrf2. Evidence that the coffee-specific diterpenes cafestol and kahweol confer protection against acrolein

Higgins, L. G.; Cavin, C.; Itoh, K.; Yamamoto, M.; Hayes, J. D.

Mice fed diets containing 3% or 6% coffee for 5 days had increased levels of mRNA for NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferase class Alpha 1 (GSTA1) of between 4- and 20-fold in the liver and small intestine. Mice fed 6% coffee also had increased amounts of mRNA for UDP-glucuronosyl transferase 1 A6 (UGT1 A6) and the glutamate cysteine ligase catalytic (GCLC) subunit of between 3- and 10-fold in the small intestine. Up-regulation of these mRNAs was significantly greater in mice possessing Nrf2 (NF-E2 p45 subunit-related factor 2) than those lacking the transcription factor. Basal levels of mRNAs for NQO1, GSTA1, UGT1A6 and GCLC were lower in tissues from nrf2(-/-) mice than from nrf2(+/+) mice, but modest induction occurred in the mutant animals. Treatment of mouse embryonic fibroblasts (MEFs) from nrf2(+/+) mice with either coffee or the coffee-specific diterpenes cafestol and kahweol (C+K) increased NQO1 mRNA up to 9-fold. MEFs from nrf2(-/-) mice expressed less NQO1 mRNA than did wild-type MEFs, but NQO1 was induced modestly by coffee or C+K in the mutant fibroblasts. Transfection of MEFs with nqo1-luciferase reporter constructs showed that induction by C+K was mediated primarily by Nrf2 and required the presence of an antioxidant response element in the 5'- upstream region of the gene. Luciferase reporter activity did not increase following treatment of MEFs with 100 mumol/l furan, suggesting that this ring structure within C+K is insufficient for gene induction. Priming of nrf2(+/+) MEFs, but not nrf2(-/-) MEFs, with C+K conferred 2-fold resistance towards acrolein.

Source : Toxicol Appl Pharmacol 2008 vol.226 (3), pp 328 - 337

Caffeine increases ambulatory glucose and postprandial responses in coffee drinkers with type 2 diabetes

Lane, J. D.; Feinglos, M. N.; Surwit, R. S.

No abstract available

Source : Diabetes Care 2008 vol.31 Iss(2), pp 221 - 222

Maternal smoking, alcohol consumption, and caffeine consumption during pregnancy in relation to a son\'s

Mongraw-Chaffin, M. L.; Cohn, B. A.; Cohen, R. D.; Christianson, R. E.

The Child Health and Development Studies is a > or =40-year follow-up of 20,754 pregnancies occurring between 1959 and 1967 in California. There were 84 cases of undescended testes at birth persisting to at least age 2 years among 7,574 liveborn sons whose mothers were interviewed in early pregnancy. Cases were matched to three controls on birth year and race. Compared with mothers of controls, mothers of cryptorchid boys consumed more caffeine during pregnancy (odds ratio = 1.4, 95% confidence interval: 1. 1, 1.9 for an interquartile range equivalent to three cups of coffee per day) but were not more likely to smoke or drink alcohol when all behaviors were considered together. Other maternal and perinatal risk factors were not significantly associated with persistent cryptorchidism and did not confound the association with caffeine.

Source :  Am J Epidemiol 2008 vol.167 (3), pp 257 - 261

Timing of blood pressure measurement related to caffeine consumption

Mort, J. R.; Kruse, H. R.

OBJECTIVE: To determine whether patients should wait 30 minutes after caffeine consumption to have their blood pressure measured. DATA SOURCES: Literature was obtained by searching MEDLINE (1980- September 2007), International Pharmaceutical Abstracts (1980-September 2007), and the Cochrane Database of Systematic Reviews (1994-September 2007). Search terms included caffeine and blood pressure. Literature was also obtained from citations in relevant articles. STUDY SELECTION AND DATA EXTRACTION: Articles that examined caffeine's acute effect on blood pressure were reviewed, with additional focus on caffeine tolerance and hypertensive status. DATA SYNTHESIS: Caffeine appears to affect blood pressure through adenosine receptor inhibition and an increased release of select neurotransmitters. Caffeine levels peak 30-120 minutes after oral intake and caffeine's half-life is 3-6 hours. The effect of caffeine on blood pressure has been examined for decades, with variable results depending on factors such as population examined (eg, hypertensive status, physical stressors, age) and study design (eg, acute effects, chronic ingestion, retrospective epidemiologic review). Caffeine tolerance diminishes the acute effect of caffeine on blood pressure, and hypertensive individuals are more susceptible to blood pressure changes. Reviews of caffeine's acute effect on blood pressure indicate changes of 3-15 mm Hg systolic and 4-13 mm Hg diastolic. Typically, blood pressure changes occur within 30 minutes, peak in 1-2 hours, and may persist for more than 4 hours.

CONCLUSIONS: Having a patient abstain from caffeine for 30 minutes prior to blood pressure monitoring is not adequate to avoid caffeine's potential effects. An alternative approach to blood pressure monitoring would be to ask the patient about recent caffeine consumption and interpret the blood pressure reading based on this information. In addition, healthcare practitioners should provide education regarding caffeine's effects.

Source : Ann Pharmacother 2008 vol.42 (1), pp 105 - 110

Comparison of the effects of inorganic phosphate on caffeine-induced Ca2+ release in fast- and slow-twitch mammalian skeletal muscle

Posterino, G. S.; Dunn, S. L.

We compared the effects of 50 mM P(i) on caffeine-induced Ca(2+) release in mechanically skinned fast-twitch (FT) and slow-twitch (ST) skeletal muscle fibers of the rat. The time integral (area) of the caffeine response was reduced by approximately 57% (FT) and approximately 27% (ST) after 30 s of exposure to 50 mM P(i) in either the presence or absence of creatine phosphate (to buffer ADP). Differences in the sarcoplasmic reticulum (SR) Ca(2+) content between FT and ST fibers [ approximately 40% vs. 100% SR Ca(2+) content (pCa 6.7), respectively] did not contribute to the different effects of P(i) observed; underloading the SR of ST fibers so that the SR Ca(2+) content approximated that of FT fibers resulted in an even smaller ( approximately 21 %), but not significant, reduction in caffeine-induced Ca(2+) release by P(i). These observed differences between FT and ST fibers could arise from fiber-type differences in the
ability of the SR to accumulate Ca(2+)-P(i) precipitate. To test this, fibers were Ca(2+) loaded in the presence of 50 mM P(i). In FT fibers, the maximum SR Ca(2+) content (pCa 6.7) was subsequently increased by up to 13 times of that achieved when loading for 2 min in the absence of P(i). In ST fibers, the SR Ca(2+) content was only doubled. These data show that Ca(2+) release in ST fibers was less affected by P(i) than FT fibers, and this may be due to a reduced capacity of ST SR to accumulate Ca(2+)-P(i) precipitate. This may account, in part, for the fatigue-resistant nature of ST fibers.

Source :  Am J Physiol Cell Physiol 2008 vol.294 (1), pp C97 - C105

Combined effects of smoking, coffee, and NSAIDs on Parkinson\'s disease risk

Powers, K. M.; Kay, D. M.; Factor, S. A.; Zabetian, C. P.; Higgins, D. S.; Samii, A.; Nutt, J. G.; Griffith, A.; Leis, B.; Roberts, J. W.; Martinez, E. D.; Montimurro, J. S.; Checkoway, H.; Payami, H.

Inverse associations of Parkinson's disease (PD) with cigarette smoking, coffee drinking, and nonsteroidal anti-inflammatory drug (NSAID) use have been reported individually, but their joint effects have not been examined. To quantify associations with PD for the individual, two-way and three-way combinations of these factors, a case-control association study with 1,186 PD patients and 928 controls was conducted. The study setting was the NeuroGenetics Research Consortium. Subjects completed a structured questionnaire regarding smoking, coffee, and NSAID consumption. Odds ratios were calculated using unconditional logistic regression. Smoking, coffee, and over the counter NSAID use as individual factors exhibited significantly reduced risks of 20% to 30%. The two-way and three-way combinations were associated with risk reduction of 37% to 49%, and 62%, respectively. Smoking and coffee exhibited significant inverse risk trends with increasing cumulative exposures, suggesting dose-response relations. With respect to the combination of all three exposures, persons who were at the highest exposure strata for smoking and coffee and used NSAIDs had an estimated 87% reduction in risk (OR = 0. 13, 95% CI = 0.06-0.29). Whether this finding reflects true biologic protection needs to be investigated.

Source : Mov Disord 2008 vol.23 (1), pp 88 - 95

Caffeine inhibits UV-mediated NF-kappaB activation in A2058 melanoma cells: an ATM-PKCdelta-p38 MAPK-dependent mechanism

Ravi, D.; Muniyappa, H.; Das, K. C.

Mammalian ultraviolet (UV) radiation response is a gene induction cascade activated by several transcription factors, including NF-kappaB. Although NF-kappaB is induced by UV radiation, the signal transduction mechanism remains relatively unclear. In the present study, we show that UV-induced NF-kappaB activation is mediated by the activation of Ataxia telangiecia mutated (ATM) and protein kinase C (PKC). We also show that caffeine specifically inhibits UV-mediated NF-kappaB activation, but not TNFalpha-mediated NF-kappaB activation. In addition, our study shows that ATM, but not ATM-Rad3- related (ATR) or DNA-dependent protein kinase (DNA-PK) is involved in UV-induced NF-kappaB activation. Because SB203580 (a p38 MAPK inhibitor), or Calphostin C or rottlerin (PKC inhibitors) was able to inhibit UV-mediated NF-kappaB activation, we evaluated whether caffeine could inhibit p38 MAPK or PKC activity. Caffeine or rottlerin inhibited UV-induced phosphorylation of p38 MAPK, but not anisomycin-induced phosphorylation of p38 MAPK, suggesting that p38 MAPK is downstream of PKC. Additionally, caffeine could effectively inhibit UV-induced increases in PKC activity. Taken together, our study demonstrates that caffeine is a potent inhibitor of UV-induced NF-kappaB activation. Additionally, this inhibition occurs due to the inhibitory action of caffeine on ATM and PKC, resulting in the inhibition of p38 MAPK activation.

Source : Mol Cell Biochem 2008 vol.308 (1-2), pp 193 - 200

Caffeine regulates alternative splicing in a subset of cancer-associated genes: a role for SC35

Shi, J.; Hu, Z.; Pabon, K.; Scotto, K. W.

Alternative splicing of pre-mRNA contributes significantly to human proteomic complexity, playing a key role in development, gene expression and, when aberrant, human disease onset. Many of the factors involved in alternative splicing have been identified, but little is known about their regulation. Here we report that caffeine regulates alternative splicing of a subset of cancer-associated genes, including the tumor suppressor KLF6. This regulation is at the level of splice site selection, occurs rapidly and reversibly, and is concentration dependent. We have recapitulated caffeine-induced alternative splicing of KLF6 using a cell-based minigene assay and identified a "caffeine response element" within the KLF6 intronic sequence. Significantly, a chimeric minigene splicing assay demonstrated that this caffeine response element is functional in a heterologous context; similar elements exist within close proximity to caffeine-regulated exons of other genes in the subset. Furthermore, the SR splicing factor, SC35, was shown to be required for induction of the alternatively spliced KLF6 transcript. Importantly, SC35 is markedly induced by caffeine, and overexpression of SC35 is sufficient to mimic the effect of caffeine on KLF6 alternative splicing. Taken together, our data implicate SC35 as a key player in caffeine-mediated splicing regulation. This novel effect of caffeine provides a valuable tool for dissecting the regulation of alternative splicing of a large gene subset and may have implications with respect to splice variants associated with disease states.

Source : Mol Cell Biol 2008 vol.28 (2), pp 883 - 895

Caffeine - a valuable tool in excitation-contraction coupling research

Stephenson, D. G.

Topic : action of caffeine on the activation of skeletal muscle.

Source : J Physiol 2008 vol.586 (Pt 3),  pp 695 - 696 (full Paper)