A Hollow TFG Condensate Spatially Compartmentalizes the Early Secretory Pathway.

In the early secretory pathway, endoplasmic reticulum (ER) and Golgi membranes form a nearly spherical interface. In this ribosome-excluding zone, bidirectional transport of cargo coincides with a spatial segregation of anterograde and retrograde carriers by an unknown mechanism. We show that at physiological conditions, Trk-fused gene (TFG) self-organizes to form a hollow, anisotropic condensate that matches the dimensions of the ER-Golgi interface. Regularly spaced hydrophobic residues in TFG control the condensation mechanism and result in a porous condensate surface. We find that TFG condensates act as a molecular sieve, enabling molecules corresponding to the size of anterograde coats (COPII) to access the condensate interior while restricting retrograde coats (COPI). We propose that a hollow TFG condensate structures the ER-Golgi interface to create a diffusion-limited space for bidirectional transport. We further propose that TFG condensates optimize membrane flux by insulating secretory carriers in their lumen from retrograde carriers outside TFG cages.

Does task shifting in tuberculosis microscopy services to non-certified technicians in Afghanistan affect quality?

SETTING: Tuberculosis microscopy centres in 30 provinces in Afghanistan. OBJECTIVE: To compare the quality of sputum smear examinations in microscopy centres with microscopists who are fully certified as laboratory technicians with those performed in centres with technicians who do not have such certification (high school graduates). DESIGN: Cross-sectional record review of sputum smear microscopy slides examined by technicians and cross-checked by trained assessors as part of routine external quality assurance between July and September 2009. RESULTS: Of 129 non-certified technicians, 118 (91%) were stationed in rural health centres compared with 217/257 (84%) certified technicians. From 386 microscopy centres, 7313 slides were cross-checked. Of 257 microscopy centres with certified technicians, 42 (16%) had at least one slide with a major error compared to 23 (18%) of 129 microscopy centres staffed with non-certified technicians. The difference was not statistically significant (OR 1.11, 95%CI 0.64-1.94). The number of slides showing major errors was also similar between the centres with both certified and non-certified technicians. CONCLUSION: This study confirms the deployment of non-certified microscopy technicians to peripheral health centres throughout the country and that their performance with sputum smear microscopy is similar to that of certified technicians with 3 years of training.

Contexte : Centres d'examens microscopiques de la tuberculose dans 30 provinces d'Afghanistan.Objectif : Comparer la qualité des examens de frottis de crachats entre les centres où les microscopistes sont des techniciens de laboratoire diplômés et ceux où ils ne le sont pas (titulaires du bac).Schéma : Etude transversale des registres des examens microscopiques des lames de frottis de crachats examinés par les techniciens et vérifiés par des examinateurs formés à l'assurance de qualité externe de routine entre juillet et septembre 2009.Résultats : Sur 129 techniciens non diplômés, 118 (91%) étaient affectés dans des centres de santé ruraux comparés à 217 (84%) sur 257 techniciens diplômés. Sur 386 centres de microscopie, 7313 lames ont été vérifiées. Sur 257 centres de microscopie pourvus de techniciens diplômés, 42 (16%) avaient au moins une lame comportant une erreur grave contre 23 (18%) dans 129 centres de microscopie pourvus de techniciens non diplômés ­ la différence n'était pas significative (OR 1,11 ; IC95% 0,64­1,94). Le nombre de lames comportant des erreurs graves était également similaire parmi les centres pourvus des deux types de techniciens.Conclusion : Cette étude confirme le déploiement de techniciens en microscopie non diplômés dans les centres de santé périphériques à travers tout le pays et montre que leur performance en matière d'examens de frottis de crachats est similaire à celle des techniciens diplômés après 3 années de formation.

Marco de referencia: Los centros de microscopia de la tuberculosis (TB) en 30 provincias de Afganistán.Objetivo: Comparar la calidad del examen microscópico del esputo entre los diferentes centros con microscopistas debidamente acreditados como técnicos de laboratorio y los centros con técnicos que no cuentan con esta acreditación (bachilleres).Método: Se llevó a cabo un estudio transversal mediante el análisis de los registros de las baciloscopias examinadas por los técnicos y una nueva verificación por asesores capacitados, en el marco del sistema ordinario de garantía externa de la calidad, entre julio y septiembre del 2009.Resultados: De los 129 técnicos no acreditados, 118 (91%) operaban en centros de salud rurales, en comparación con 217 (84%) de los 257 técnicos acreditados. Se verificaron de nuevo 7313 baciloscopias de los 386 centros de microscopia. De los 257 centros que contaban con técnicos certificados, en 42 (16%) se observó como mínimo un frotis con un error grave de lectura, en comparación con 23 casos (18%) en los 129 centros con personal no acreditado; esta diferencia no fue estadísticamente significativa (OR 1,11; IC95% 0,64­1,94). El número de baciloscopias que presentaron errores graves también fue análogo en los centros con personal técnico de ambos tipos.Conclusión: Los resultados del presente estudio confirman el despliegue de técnicos en microscopia no certificados hacia los centros periféricos en todo el país, cuyo desempeño es equivalente al desempeño de los técnicos que reciben la acreditación tras 3 años de capacitación.

The pattern of cryptosporidiosis in experimentally immune deficient albino rats.

Thirty clean laboratory bred male albino rats were divided into two groups. G1, twenty rats received corticosteroids (SC. injection of 1.5 mg dexamethasone, twice per week) for eight weeks for immuno-suppression, while G2, ten rats served as controls. Both groups were separately caged under controlled laboratory observation and given normal diet. After the 8th week, both groups were allowed to acquire Cryptosporidium parvum infection by feeding on infective source. Another week more, all animals were subjected to stool examination and were then sacrificed. Rats of G1 showed oocysts in 13/16, but none in rats of G2. Scrapping of the intestinal mucosa from both rats of G1 and G2 were prepared for microscopic examination, after stained in modified Kinyoun acid-fast (light microscope), and Auramine (fluorescent microscope). Cryptosporidium oocysts were demonstrated in 13/16 (81.3%) of G1 and 3/10 (30%) of G2. So, cryptosporidiosis as an opportunistic parasite threats in immune deficiency.

Acetates and benzoates of alkyl catechols and evaluation of their antibacterial activity.

Potential biologically active alkyl catechol esters were prepared and their antibacterial activity was determined against 12 Gram-positive and 16 Gram-negative bacteria. Esterification (acetylation and benzoylation) of mono-, di- and tetra- substituted alkyl catechols afforded the di-acetyl and di-benzoyl derivatives in each case. In the primary screening it was observed that the substitution of hydroxyl group in alkyl catechol with an acyl group generally resulted in a decrease of antibacterial activity. A number of acetyl and benzoyl derivatives inhibited the growth of Salmonella typhi. In case of Gram-positive bacteria only di-O-benzoyl-3,5,6,-tetra-(3-hexyl) catechol (26) showed a significant activity.

Chemistry and biological activity of a tryptamine and beta-carboline series of bases.

Twenty-six derivatives of harmaline and tetrahydroharmine were prepared and characterized by UV, IR, MS, and NMR spectroscopy. They were tested for their antimicrobial, antiplatelet aggregation and cytotoxic activity. Their effect on central nervous system was also studied.

A comparative study of unpassaged and animal passaged cultures of Listeria monocytogenes in rabbits.

Variants of a parent culture of Listeria monocytogenes were prepared by passaging it several times through rabbits. The resulting isolates (V1 to V6) were investigated and compared with the parent culture with particular emphasis on their phenotypic characters and their pathogenicity for rabbits. The variants maintained the morphological, cultural, biochemical and serological features of the parent strain. Although no significant decrease was noted in the total extracellular protein produced, 10 mg/ml of a 6-day culture broth grown at 34 degrees C for V6 as compared to 12.3 mg/ml for the parent culture, the phosphocholine-specific phospholipase C (PC-PLC) activity diminished with passaging. Pathogenicity for rabbits, as determined by viable count of the organism per gram of the infected organ, increased at each passage. Animals infected with V6 revealed a mean of 2.2 x 10(9) CFU/g of spleen as compared to the parent culture which had a count of 5.0 x 10(6) CFU/g. These observations indicate a lack of direct correlation between in vitro production of PC-PLC and virulence of L. monocytogenes for rabbits.

In vitro studies of the antibacterial and antifungal activity of oxine and its derivatives.

Twenty-one derivatives of 8-hydroxyquinoline (oxine, 8H, CAS 148-24-3) were prepared and characterized by UV, IR, MS and NMR spectroscopy. Four of these derivatives, N-butyl, 8-butyloxyquinolinium bromide (HBD), 8-pentyloxyquinoline (HPEM), N-pentyl, 8-pentyloxyquinolinium bromide (HPED) and N-benzyl, 8-benzyloxy quinolinium chloride (HBED) are new and reported for the first time. The antimicrobial activity of these compounds was carried out in vitro against 11 Gram positive and 18 Gram negative bacteria, and 18 fungi including 9 dermatophytes, 7 other filamentous fungi and 2 Candida species. Three compounds namely, HPRD, HPED and HBED were found to possess significant antibacterial activity in order of HPED > HPRD > HBED, whereas 4 were found to possess significant antifungal activity in order of 8H > HT > HPEM > 8B.

The effect of pH and temperature on haemolysin production by Listeria species.

The ability of three strains of Listeria monocytogenes NCTC 7973, serovar 1/2a, NCTC 5124m serovar 4a, C-274 serovar 4b and one strain of L. seeligeri (SLCC 3954) to grow in TPB (Tryptose phosphate agar) at pH values between 5-9 and produce haemolysin has been investigated at two incubation temperatures. The minimum and maximum pH values at which haemolysin was detected were 5 and 9 respectively, at 20 degrees and 32 degrees C.

Synthesis of alkyl catechols and evaluation of their antibacterial and cyfotoxic activity.

A series of potential biologically active mono-, di- and tetra- alkyl catechols were prepared through Friedel- Crafts alkylation of catechol, and evaluated for their antibacterial and cytotoxic activity. The mono-substituted alkyl derivatives showed maximum antibacterial activity in vitro which increased with the increasing length of the alkyl chains. Primary screening results indicated that all the monoalkyl derivatives except 4- (2-octyl) catechol inhibited the growth of B. bronchoseptica and maximum zones of inhibition were observed in case of monohexyl catechols (both n- and 2-hexyl) and monobenzyl derivative. In case of Gram-negative organisms growth of Kl. pneumoniae and A. calcoaceticus was inhibited by several derivatives. Mono-3-octyl-, monononyl- and monobenzyl catechols markedly inhibited the growth of Kl. pneumoniae. Mono-2-heptyl catechol inhibited the growth of six Gram-negative bacteria. Minimum inhibitory concentration of six most active compounds of the series was determined against Gram-positive and Gram-negative organisms; it ranged from < 100 mug/ml to l0 mug/ml. The antibacterial activity of catechol was not significant. Cytotoxicity test done by brine shrimp assays showed that the order of cytotoxicity decreases in going from mono- to tetra- alkyl catechols, and among the mono- alkyl products, a decrease in order of cytotoxicity was noted in going from mono-methyl catechol (LD(50) = 59) to monopentyl catechol (LD(50) = 173) after which the order of cytotoxicity gradually increased upto the largest alkyl substituent tested i.e. monononyl catechol (LD(50) = 114). Methyl and ethyl catechol, which were almost inactive in respect of their antibacterial activity possessed prononounced cytotoxicity as compared to higher homologues. Catechol itself did not show significant cytotoxicity (LD(50) = 393.27).

In vitro antibacterial studies of some newly synthesized phenacyl-thiosemicarbazones.

Four different phenacyl-thiosemicarbazone compounds were studied for their antibacterial activity against seventeen different species/strains. Of the four compounds under study, O-methoxy- phenacyl-thiosemicarbazone was found to be highly active against almost all the cultures under study. The other compounds were also found to possess antibacterial spectrum, but in very high concentrations for some of the cultures.