Contribution to the taxonomy of the Ectocarpales (Phaeophyceae) from the coast of Karachi, Pakistan

BEGUM, M. & KHATOON, N., 1992. Contribution to the taxonomy of the Ectocarpales (Phaeophyceae) from the coast of Karachi (Pakistan). The taxomony and ecology of five species belonging to the order Ectocarpales, representing three genera– Ectocarpus with one species, Hincksia with three species and Nemacystus with one species–are studied and reported as new records for the coast of Karachi, Pakistan.     

The reproductive cycle in the population of Saccostrea cuccullatta (Born) from the coast of Karachi,Pakistan

Periphytic diatom communities on clay tile and sterilized rock substrates were compared with those on natural substrates. Clay tiles yielded diatom communities with the least variability between replicate samples, and the greatest similarity to the natural substrate assemblage. The advantages of utilizing introduced substrate communities and problems encountered with their simulation of the natural substrate community are discussed.     

Screening for anticoagulant activity in marine algae from the Northwest Mexican Pacific coast

Disorders in blood coagulation can lead to an increased risk of bleeding (hemorrhage) or clotting (thrombosis). These illnesses have increased over the last decades and no useful new substances have been discovered to remediate them. In search of new compounds from marine natural resources, macroalgae from the Northwest Mexican Pacific coast were investigated in order to detect anticoagulant activity. Egregia menziesii, Ulva neumatoidea, Porphyra perforata, Silvetia compressa, and Codium fragile were collected from Ensenada coasts. Collected materials were cleaned, dried, milled, and stored until use. Proximate chemical composition and sulfate content were determined in dried powder. Hot and cold aqueous extracts were obtained from the dried algae in order to isolate polysaccharides and similar compounds. Methanol-soluble compounds were separated by means of Soxhlet extraction. Organic and aqueous extracts were screened for anticoagulant activity in both intrinsic and extrinsic pathways of clot formation. Clotting activity was studied by standardized plasma coagulation tests (activated partial thromboplastin time (aPTT) and prothrombin time (PT)). Heparin, a sulfated glycosaminoglycan widely used in anticoagulant therapy, was used as reference. Effects were defined either as aPTT index (Sample aPTT/Control aPTT ratio) or PT index (Sample PT/Control PT ratio). Some of the fractions showed anticoagulant activity over intrinsic pathways, whereas they were found to be coagulants on the extrinsic pathway. The highest aPTT index was 1.8 for U. nematoidea (1 μg mL⁻¹). Hot aqueous extracts from E. menziesii (1 μg mL⁻¹) showed the highest potency, with an aPTT index of 1.4. Sulfate content and anticoagulant activity were not correlated.     

Sublittoral ecology of marine algae on the North Wales coast

Summary 1. Diving work carried out between April 1964 and July 1966 on the North Wales coast (Anglesey) showed that the west coast stations A and B could be divided into four distinct sublittoral regions, the east coast station showed a more irregular distribution of the flora.2. The four distinct regions were: TheLaminaria forest, the rock below theLaminaria zone, the bed of loose stones supporting algae in summer, and the bed of sand supportingLaminaria saccharina.3. The distribution of algae at station C was more dependant upon the local topography of the boulders making up the sea bed.4. There was a difference between the fruiting periods of algae growing at a great depth and in the shallow water.

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Sublitorale Ökologie mariner Algen an der Küste von Nord-Wales

Kurzfassung Über die sublitorale Pflanzenwelt bei Anglesey und Caernarvonshire ist relativ wenig bekannt. Das Ziel unserer im Oktober 1964 begonnenen Taucharbeiten war daher, die Kenntnisse über Artengefüge, Verbreitung und vegetative sowie reproduktive Jahreszyklen zu vertiefen. Die Wirkungen von Temperatur, Licht, Wellenexposition und Sporenverbreitung wurden untersucht und zu den gefundenen Verbreitungswerten in Beziehung gesetzt. Es zeigte sich, daß die Westküsten A und B in 4 verschiedene Sublitoralregionen unterteilt werden könne, während an den Ostküstenstationen eine einheitlichere Verbreitung vorherrschte. Die 4 unterscheidbaren Westküstenregionen waren der Laminarienwald, der Felsbereich unterhalb der Laminarien, das Bett loser Steine und das Sandbett mitLaminaria saccharina. Bei Station C hängt die Algenverbreitung mehr von der lokalen Topographie ab. Die Fortpflanzungszeiten der Algen erwiesen sich als abhängig von der Wassertiefe am Standort.

     

Contribution to the taxonomy and ecology of the Azorean benthic marine algae

Algal zonation patterns were studied in two sites (Caloura, south coast and Ribeirinha, north coast) of the island of Sao Miguel, Azores. At each site two stations were studied and the transects revealed the occurrence of two distinct and well established algal zones. In the first zone, daily immersed and emersed by the tide, the algae were growing in a dense and short tangle forming a mat, referred to as algal turf. In the second zone, which was wet most of the time, the algae were larger and frondose. A list of the species of benthic marine algae occurring on the algal turf of each station is given. Of the total of 47 species found, eight are new for the Azores and another 13 species are recorded for the first time for Sao Miguel. Gigartina acicularis (Roth) Lamouroux and articulate coralline algae (Corallina oficinalis Linnaeus and Jania spp.) were the more common species. Seasonal variation of the algal turf was studied and related to mean monthly values of air and sea water temperatures, insolation and hours of light. The zonation patterns and composition of algal species were compared with those from other open rocky shores.     

Antibacterial substances from marine algae isolated from Jeddah coast of Red sea,Saudi Arabia

Marine algae are known to produce a wide variety of bioactive secondary metabolites and several compounds have been derived from them for prospective development of novel drugs by the pharmaceutical industries. However algae of the Red sea have not been adequately explored for their potential as a source of bioactive substances. In this context Ulva reticulata, Caulerpa occidentalis, Cladophora socialis, Dictyota ciliolata, and Gracilaria dendroides isolated from Red sea coastal waters of Jeddah, Saudi Arabia, were evaluated for their potential for bioactivity. Extracts of the algae selected for the study were prepared using ethanol, chloroform, petroleum ether and water, and assayed for antibacterial activity against Escherichia coli ATCC 25322, Pseudomonas aeruginosa ATCC 27853, Stapylococcus aureus ATCC 29213, and Enterococcus faecalis ATCC 29212. It was found that chloroform was most effective followed by ethanol, petroleum ether and water for the preparation of algal extract with significant antibacterial activities, respectively. Results also indicated that the extracts of red alga G. dendroides were more efficient against the tested bacterial strains followed by green alga U. reticulata, and brown algae D. ciliolata. Chemical analyses showed that G. dendroides recorded the highest percentages of the total fats and total proteins, followed by U. reticulata, and D. ciliolate. Among the bioflavonoids determined Rutin, Quercetin and Kaempherol were present in high percentages in G. dendroides, U. reticulata, and D. ciliolate. Estimation of saturated and unsaturated fatty acids revealed that palmitic acid was present in highest percentage in all the algal species analyzed. Amino acid analyses indicated the presence of free amino acids in moderate contents in all the species of algae. The results indicated scope for utilizing these algae as a source of antibacterial substances.     

Pathways to Care: Duration of Untreated Psychosis from Karachi,Pakistan

Background

Substantial amount of time is lost before initiation of treatment in Schizophrenia. The delay in treatment is labelled as Duration of Untreated Psychosis (DUP). Most of these estimates come from western countries, where health systems are relatively better developed. There is dearth of information on pathway to care from developing countries.

Methods and Results

Patients with ICD-10 based diagnosis of Schizophrenia were enrolled by convenient method of sampling. The pathway to care was explored through a semi-structured questionnaire. Onset, course and symptoms of psychosis were assessed using Interview for the Retrospective Assessment of the Onset of Schizophrenia (IRAOS). Ethical approval of the project was taken from The Aga Khan University, Ethics Review Committee. Of the enrolled 93 subjects, 55 (59%) were males and 38 (41%) were females. In our sample, 1.56 mean (median, 2) attempts were made prior to successful help seeking. The duration of untreated psychosis was 14.8 months (St. Deviation; 29.4). DUP was 16.8 months (St. Deviation; 34.9) for males and 11.8 months (St. Deviation; 18.9) for females. In the pathway to care, psychiatrists featured prominently as initial care providers. In the first attempt at help-seeking, 43% patients were initially taken to psychiatrists. After the initial consultation, 45% were prescribed psychotropic medication while 7% were hospitalized. Only 9% subjects were given the diagnosis of schizophrenia initially. When participants were inquired about the reasons for delay, 29% reported financial difficulties as the barrier to care. Positive symptoms of psychosis were present in 57% subjects while negative symptoms were present in 30% subjects. There was a statistically significant difference (Chi-square; 7.928, df: 1, Sig 0.005) between DUP and the positive and negative symptoms category.

Conclusion

In the absence of well developed primary care health system in Pakistan, majority of patients present to psychiatrists as a first contact. DUP, as a measurement of help seeking behaviour, tends to be shorter with positive symptoms of Schizophrenia. Substantial amount of time is lost due to non recognition of disease and subsequently, inadequate treatment. Secondary prevention strategies should focus on families, which play an important role in the treatment-seeking process of psychotic patients.     

Photosynthetic acclimation to solar UV radiation of marine red algae from the warm-temperate coast of southern Spain: A review

A review is presented of the physiological mechanisms developed bybenthic macroalgae to cope with deleterious wavelengths, particularly UVradiation. Photoinhibition of photosynthesis, is a photoprotectivemechanism in various species studied in southern Spain. Incubations inoutdoor systems and transplantation experiments under natural radiationallowed to led to understanding of some the photoprotective strategies usedby red algae. Under conditions of enhanced UV-B radiation, algae inshallow sites show marked photoinhibition and rapid recovery ofphotosynthesis (dynamic photoinhibition), whereas algae from deeperlocations can suffer photodamage (chronic photoinhibition). Theexpression of this photoprotective strategy by intertidal species representsan efficient physiological adaptation to tolerate deleterious irradiance, whenlow tides coincide with the onset of solar radiation. Subtidal species canbe also exposed to high doses of UV radiation. This is particularly evidentin clear, Mediterranean waters, where light (including UV-B) can reach to10 m depth. The implications of photoacclimation processes formacroalgal ecology in warm-temperate littorals and the possibleconsequences for outdoor cultivation are outlined in terms of environmentalUV variability.     

Prevalence of Chlamydia trachomatis infections in Karachi, Pakistan.

An epidemiological study was carried out to determine the prevalence of Chlamydia infections in adult females by enzyme immunoassay and microscopic examination of Giemsa-stained smears. Endocervical swabs were collected from 126 females attending OB/GYN ward at Abbasi Shaheed Hospital, Karachi. 13.5% of 126 females tested were positive by enzyme immunoassay and only 5.6% were positive by the Giemsa-staining method. The infection rate among pregnant and nonpregnant women with urinogenital problems were 11.8% and 14.7%, respectively. The majority of females complained of excessive cervical discharge and pain in the lower abdomen. A high prevalence of infection in normal pregnant women (18.2%) indicates the asymptomatic nature of this infection.     

The mutagenicity of natural products from marine algae.

5 polyhalogenated hydrocarbon natural products isolated from the marine red alga Plocamium spp. were tested for mutagenicity in the Ames reversion assay. All 5 of the compounds induced revertants in Salmonella typhimurium strains TA100 and TA1535, indicating the mutational events involved base substitutions. One of the compounds, designated cross-conjugated ketone, was shown to be almost 200 times more effective as a mutagen than was ethyl methanesulfonate.     

Antibiotic activity of lectins from marine algae against marine vibrios

Saline and aqueous ethanol extracts of marine algae and the lectins from two red algal species were assayed for their antibiotic activity against marine vibrios. Experimental studies were also carried out on the influence of environmental factors on such activity, using batch cultures. The results indicated that many of the saline extracts of the algal species were active and that the activity was selective against those vibrios assayed. The algal extracts were active against Vibrio pelagius and the fish pathogen V. vulnificus, but inactive against V. neresis. Algal lectins from Eucheuma serra (ESA) and Galaxaura marginata (GMA) strongly inhibited V. vulnificus but were inactive against the other two vibrios. The antibacterial activity of algal extracts was inhibited by pretreatment with various sugars and glycoprotein. Extracts of the two red algae, E. serra and Pterocladia capillacea, in saline and aqueous ethanol, inhibited markedly the growth rate of V. vulnificus at very low concentrations. Culture results indicated that metabolites active against V. vulnificus were invariably produced in P. capillacea over a wide range of temperature, light intensity, and nutritional conditions. Enhanced antibacterial activity occurred when P. capillacea was grown under higher irradiance, severe nutrient stress and moderate temperature (20 °C), reflecting the specific antibiotic characteristics of this alga. The strong antibiotic activity of lectins towards fish pathogenic bacteria reveals one of the important roles played by algal lectins, as well as the potential high economic value of those marine algae assayed for aquaculture and for biomedical purposes.     

Phylogenetic analysis of HDV isolates from HBsAg positive patients in Karachi, Pakistan

ABSTRACT: BACKGROUND: In spite of a high occurrence of Hepatitis Delta in the province of Sindh in Pakistan, no genetic study of Hepatitis Delta virus (HDV) isolates from this region was carried out. The aim of this study is to analyze the genetic proximity within local HDV strains, and relationship with other clades of HDV, using phylogenetic analysis. RESULTS: Phylogenetic analysis of nucleotide sequences of the Hepatitis Delta Antigen (HDAg) R0 region obtained in this study, showed considerable diversity among the local strains with a potential subgroup formation within clade I. The multiple sequence alignment of predicted amino acids within clade I showed many uncommon amino acid substitutions within some conserved regions that are crucial for replication and assembly of HDV. CONCLUSIONS: The studied strains showed a range of genetic diversity within HDV clade I. There is clustering of sequences into more than one group, along with formation of potential subgroup within clade I. Clustering shows the genetic closeness of strains and indicates a common origin of spread of HDV infection. Further phylogeny-based studies may provide more information about subgroup formation within clade I and may be used as an effective tool in checking and/or preventing the spread of hepatitis D virus infection in this region.