The effects of lesioning both the superior colliculus and the substantia nigra of cats on turning behavior

In twenty two adult cats, distributed in four groups, stainless steel electrodes were implanted in the superior colliculus and the substantia nigra of both sides in order: 1) to find the current intensity threshold values necessary to evoke turning behavior, and record their variations after lesion of the cited structures; 2) to study the effects of lesioning two of these structures, specifically related to the direction of turning behavior, and 3) to assess the time-course of recovery from postural asymmetry after damaging two structures involved in rotation behavior, located either in the same or in the opposite side, as well as the importance of performing these lesions simultaneously or at different periods. Three main results were observed: 1) a large proportion of lesioned cats showed an increase in threshold values necessary to evoke rotation of the implanted structures located either in the same or in the opposite side; 2) the lesions induced in a significant number of cats a transient postural asymmetry. After lesioning the superior colliculus, the direction of turning was towards the damaged hemisphere. Apomorphine injected fourteen days later demonstrated the existence of an occult asymmetry, and the direction of turning was maintained. In the substantia nigra lesioned animals, the direction of turning, was towards the non-lesioned side. Apomorphine reversed the direction of turning; 3) the cats showed a remarkable capacity to recover from the postural asymmetry produced by the lesion. This experimental series further support the hypothesis of a close functional relationship between structures of both cerebral hemispheres related to turning behavior.     

Release of bound immunoglobulin from SSPE brain by acid elution.

SSPE brain homogenate extracted at pH 7.4 yields immunoglobulin with a 4- to 5-fold greater hemagglutination inhibition activity per microgram of IgG than serum from the same patient. Serial washing of the homogenate results in a low level steady-state release of IgG. Elution of the washed sediment with pH 2.5, 0.1 M glycine buffer results in a 2- to 3-fold increase in recovery of hemagglutination inhibition activity with a greater hemagglutination inhibition activity per milligram of IgG than the IgG recovered by phosphate-saline extraction at pH 7.4.     

Rab11‐Family of Interacting Protein 2 associates with chlamydial inclusions through its Rab‐binding domain and promotes bacterial multiplication

Chlamydia trachomatis, an obligate intracellular pathogen, survives within host cells in a special compartment named ‘inclusion’ and takes advantage of host vesicular transport pathways for its growth and replication. Rab GTPases are key regulatory proteins of intracellular trafficking. Several Rabs, among them Rab11 and Rab14, are implicated in chlamydial development. FIP2, a member of the Rab11‐Family of Interacting Proteins, presents at the C‐terminus a Rab‐binding domain that interacts with both Rab11 and Rab14. In this study, we determined and characterized the recruitment of endogenous and GFP‐tagged FIP2 to the chlamydial inclusions. The recruitment of FIP2 is specific since other members of the Rab11‐Family of Interacting Proteins do not associate with the chlamydial inclusions. The Rab‐binding domain of FIP2 is essential for its association. Our results indicate that FIP2 binds to Rab11 at the chlamydial inclusion membrane through its Rab‐binding domain. The presence of FIP2 at the chlamydial inclusion favours the recruitment of Rab14. Furthermore, our results show that FIP2 promotes inclusion development and bacterial replication. In agreement, the silencing of FIP2 decreases the bacterial progeny. C. trachomatis likely recruits FIP2 to hijack host intracellular trafficking to redirect vesicles full of nutrients towards the inclusion.     

Adiposity, physical activity, and physical fitness among children from Aragón, Spain

Objective: The main purpose of this study was to determine the relationship between physical activity (PA) levels and adiposity. The secondary purpose was to assess the effect of physical fitness and living area on adiposity. Research Methods and Procedures: A cross‐sectional study was carried out in a regional representative sample of 1068 children 7 to 12 years of age. Anthropometric and physical fitness values (including BMI, aerobic capacity, strength levels, velocity assessment, and flexibility) were measured in all children. Results: The prevalence of being overweight and obese in the entire sample was 31% and 6%, respectively. No difference between urban and rural children was found. The proportion of boys who were classified as overweight and obese was similar in physically active and sedentary (non‐physically active) groups. However, physically active girls tended to show lower obesity prevalence compared with their sedentary counterparts (p = 0.06). In girls, the sum of the 6 skinfolds thickness (SSF) measurements was lower in the physically active group when compared with the non‐physically active group (p < 0.05); however, this effect was not observed in boys. Multiple regression analysis revealed that the level of physical activity (PA) had a significant effect on BMI and SSF in boys but not in girls, while maximal oxygen uptake (Vo _2max) was significantly related to adiposity in both sexes. Discussion: Regular participation in at least 2 hours per week of sports activities on top of the compulsory education program is associated with better physical fitness and lower whole body adiposity. In the children included in our study, among all physical fitness variables, Vo _2max showed the strongest relationship with BMI and fat mass assessed by means of skinfold measurements.     

A review of the world marine gastropod fishery: evolution of catches, management and the Chilean experience

Marine mollusks are among the most importantinvertebrate fisheries in the world. The mainclasses of mollusk fished are Cephalopoda,Bivalvia and Gastropoda. Marine gastropodsrepresent approximately 2% of the mollusksfished in the world. Several species ofgastropods, such as Haliotis spp., Strombus spp., Busycon spp. and Concholepas concholepas, have high economicvalue in international markets and playimportant social roles in small-scale artisanalfisheries. In the past 25 years wild-stockcatches of marine gastropods have increasedfrom 75,000 mt in 1979 to 103,000 mt in 1996.During the same period the countries involvedin gastropod landings rose from 23 to 47.Gastropods are fished mainly in: (1) theAmerican continent, dominated by the extractionof the muricid ``loco', C. concholepas, inChile and Peru; strombid conchs, Strombusspp., in the Caribbean, and abalone, Haliotis spp., in California and the west coastof the Baja California peninsula; (2) Asia andOceania, with the dominate abalone fishery,mainly in Australia and New Zealand, and thehorned turban snail, Turbo truncatus, inJapan and Korea; (3) in Africa and Europe, thedominate species extracted are Haliotismidae, heavily fished in South Africa, and thecommon periwinkle, Littorina littorea,and the whelk Buccinum undatum, which areextracted in Europe. This review summarizes the fishery of abalonespecies in California and the west coast of theBaja California peninsula. We highlightoverfishing situations and the utilization ofadaptive management tools, such as those inoperation in Baja California, where small-scalefisher associations (cooperatives) havereceived exclusive access rights to abaloneextraction within specific fishing zones, since1936. We also review the abalone fishery inAustralia, and the use of IndividualTransferable Quotas (ITQs) and Total AllowableCommercial Catches (TACC), which have been inuse since the mid-1980's. We describe thegastropod fisheries in Chile, mainly C. concholepas, highlighting their economic andsocial importance. We provide information onthe evolution of catches and exports anddiscuss the development of novel managementadaptive tools, such as the implementation ofthe Benthic Regime for Extraction andProcessing (BREP), the introduction ofNon-Transferable Individual Quotas (NTIQs) andterritorial users rights for benthic fisheries,such as the Management and Exploitation Areas(MEAS). Finally, we present and discuss thenecessary steps for the sustainable managementof marine gastropods and other benthic resources.     

Loss of Prolyl Carboxypeptidase in Two-Kidney,One-Clip Goldblatt Hypertensive Mice

It is well documented that angiotensin (Ang) II contributes to kidney disease progression. The protease prolyl carboxypeptidase (PRCP) is highly expressed in the kidney and may be renoprotective by degrading Ang II to Ang-(1-7). The aim of the study was to investigate whether renal PRCP protein expression and activity are altered in two-kidney, one-clip (2K1C) Goldblatt hypertensive mice. Left renal artery was constricted by using 0.12 mm silver clips. Blood pressure was measured using telemetry over the eleven weeks of study period and revealed an immediate increase in 2K1C animals during the first week of clip placement which was followed by a gradual decrease to baseline blood pressure. Similarly, urinary albumin excretion was significantly increased one week after 2K1C and returned to baseline levels during the following weeks. At 2 weeks and at the end of the study, renal pathologies were exacerbated in the 2K1C model as revealed by a significant increase in mesangial expansion and renal fibrosis. Renal PRCP expression and activity were significantly reduced in clipped kidneys. Immunofluorescence revealed the loss of renal tubular PRCP but not glomerular PRCP. In contrast, expression of prolyl endopeptidase, another enzyme capable of converting Ang II into Ang-(1-7), was not affected, while angiotensin converting enzyme was elevated in unclipped kidneys and renin was increased in clipped kidneys. Results suggest that PRCP is suppressed in 2K1C and that this downregulation may attenuate renoprotective effects via impaired Ang II degradation by PRCP.     

Exposure to sub-inhibitory concentrations of cefotaxime enhances the systemic colonization of Salmonella Typhimurium in BALB/c mice

It has been proposed that sub-inhibitory concentrations of antibiotics play a role in virulence modulation. In this study, we evaluated the ability of Salmonella enterica serovar Typhimurium (hereafter S. Typhimurium) to colonize systemically BALB/c mice after exposure to a sub-inhibitory concentration of cefotaxime (CTX). In vivo competition assays showed a fivefold increase in systemic colonization of CTX-exposed bacteria when compared to untreated bacteria. To identify the molecular mechanisms involved in this phenomenon, we carried out a high-throughput genetic screen. A transposon library of S. Typhimurium mutants was subjected to negative selection in the presence of a sub-inhibitory concentration of CTX and genes related to anaerobic metabolism, biosynthesis of purines, pyrimidines, amino acids and other metabolites were identified as needed to survive in this condition. In addition, an impaired ability for oxygen consumption was observed when bacteria were cultured in the presence of a sub-inhibitory concentration of CTX. Altogether, our data indicate that exposure to sub-lethal concentrations of CTX increases the systemic colonization of S. Typhimurium in BALB/c mice in part by the establishment of a fitness alteration conducive to anaerobic metabolism.     

Escherichia coli Heat-Stable Enterotoxin Mediates Na+/H+ Exchanger 4 Inhibition Involving cAMP in T84 Human Intestinal Epithelial Cells

The enterotoxigenic Escherichia coli strains lead to diarrhoea in humans due to heat-labile and heat-stable (STa) enterotoxins. STa increases Cl^-release in intestinal cells, including the human colonic carcinoma T₈₄ cell line, involving increased cGMP and membrane alkalization due to reduced Na⁺/H⁺ exchangers (NHEs) activity. Since NHEs modulate intracellular pH (pH_i), and NHE1, NHE2, and NHE4 are expressed in T₈₄ cells, we characterized the STa role as modulator of these exchangers. pH_i was assayed by the NH₄Cl pulse technique and measured by fluorescence microscopy in BCECF–preloaded cells. pH_i recovery rate (dpHi/dt) was determined in the absence or presence of 0.25 μmol/L STa (30 minutes), 25 μmol/L HOE-694 (concentration inhibiting NHE1 and NHE2), 500 μmol/L sodium nitroprusside (SNP, spontaneous nitric oxide donor), 100 μmol/L dibutyryl cyclic GMP (db-cGMP), 100 nmol/L H89 (protein kinase A inhibitor), or 10 μmol/L forskolin (adenylyl cyclase activator). cGMP and cAMP were measured in cell extracts by radioimmunoassay, and buffering capacity (ßi) and H⁺ efflux (J _H ⁺) was determined. NHE4 protein abundance was determined by western blotting. STa and HOE-694 caused comparable reduction in dpHi/dt and J _H ⁺ (~63%), without altering basal pH_i (range 7.144–7.172). STa did not alter ßi value in a range of 1.6 pH_i units. The dpHi/dt and J _H ⁺ was almost abolished (~94% inhibition) by STa + HOE-694. STa effect was unaltered by db-cGMP or SNP. However, STa and forskolin increased cAMP level. STa–decreased dpHi/dt and J _H ⁺ was mimicked by forskolin, and STa + HOE-694 effect was abolished by H89. Thus, incubation of T₈₄ cells with STa results in reduced NHE4 activity leading to a lower capacity of pH_i recovery requiring cAMP, but not cGMP. STa effect results in a causal phenomenon (STa/increased cAMP/increased PKA activity/reduced NHE4 activity) ending with intracellular acidification that could have consequences in the gastrointestinal cells function promoting human diarrhoea.