Haiti The First Republican Country In Latin America History Essay

History » Haiti The First Republican Country In Latin America History Essay

Haiti is the first republican country in Latin America. It gained its independence in 1804 and it has the world’s first black led government. Though Haiti has a rich historical background, it is counted as one of the least developed countries in the world and it is heavily obliged to the World Bank.

Haitian geography is very diverse. From mountain ranges to coastal plains, all exist in harmony in this Caribbean island. Many selection of flora and fauna are originated there. But due to the rushed trend of modern urbanization many species have perished.

Haiti is situated near the northern boundary where the Caribbean tectonic plate shifts towards east by about 20mm per year in relation to the North American plate. This places Haiti in a very risky position, as it means that Haiti is very vulnerable to quakes, cyclones and other dire weather conditions due to the tectonic plate movements.

The worst quake to hit Haiti in about 200 hundred years was on January 12th 2010. It was of magnitude 7.0 followed by 12 aftershocks, each of magnitude greater than 5.0. It caused about 230,000 deaths, 300,000 injuries and about another 1,000,000 left homeless.

Communication methods, air, land, and sea transport facilities, hospitals, and electrical networks had been destroyed by the quake, which hampered rescue and aid efforts.

Many of the world’s countries pitched in to help Haiti back to its feet. A telethon was held and it raised about US$58 million.

With the increasing frequency of earthquakes, tsunamis and other natural disasters, Haiti was yet another unfortunate bearer of tragedy when an earthquake shook the very souls of the poorest nation in the Western Hemisphere. Fortunately, support from all the ends of the Earth has come to surpass this unavoidable and unimaginable event. This report intends to give an overview of Haiti, the earthquake and the aftermath.

Haiti was the first independent country in Latin America. It is the second largest island in the Greater Antilles and is situated in the western part of Hispaniola.  Haiti gained its independence after a slave rebellion in 1804 and it is the first black led republican country in the world.  Haiti is the poorest country in the Western Hemisphere, and is ranked 149th of 182 countries on the Human Development Index.  About 225,000 Haitian children are working as unpaid household help, which is considered as a form of modern slavery.  It was considered and the qualified as one of the countries which are heavily in debated to the IMF and the World Bank.  

Haiti has a very diverse topography and consists mainly of mountain areas.  As a result of its varied environment, there are very special native flora and fauna which are not found elsewhere. Along with the mountainous terrains are also many small coastal and valleys.  Haiti used to be a very tropically lush and forest covered country until urbanization took over.  As humans began cutting forests to make homes, many rare species of flora and fauna were endangered and farmlands destroyed. Forests were also lost as a result of erosion which was caused due to logging, which is done to get charcoal, the most important source of fuel to the country.  

The Island of Hispaniola, shared by Haiti and the Dominican Republic, is seismically active and has a history of destructive earthquakes.  Haiti is located near the northern boundary where the Caribbean tectonic plate shifts eastwards by about 20mm per year in relation to the North American plate.  The strike-slip fault system in the region has two branches in Haiti, the Septentrional-Oriente fault in the north and the Enriquillo-Plaintain Garden fault in the south; both its location and focal mechanism suggest that the January 2010 quake was caused by a rupture of the Enriquillo-Plaintain Garden fault, which had been locked for 250 years, gathering stress.  A magnitude 8.0 earthquake struck the Dominican Republic and shook Haiti on 4 August 1946, producing a tsunami that killed 1,790 people and injured many others.  The Australian government's travel advisory site had previously expressed concerns that Haitian emergency services would be unable to cope in the event of a major disaster, and the country is considered "economically vulnerable" by the Food and Agriculture Organization. It is no stranger to natural disasters; in addition to earthquakes, it has been struck frequently by cyclones, which have caused flooding and widespread damage.  

January 12th 2010, the 6th worst earthquake recorded in history with a magnitude of 7.0, hit less than ten miles from the capital of Port-au-Prince, Haiti. The preliminary earthquake was followed by twelve aftershocks greater than magnitude 5.0.  The Haitian Government reported that between 217,000 and 230,000 people had been recovered as dead, approximately 300,000 injured, and over 1,000,000 left homeless. They also projected that 250,000 residences and 30,000 commercial buildings had collapsed or were brutally damaged,  from shantytown homes to national landmarks,  including the Presidential Palace, the National Assembly building and the Port-au-Prince Cathedral.  Amongst those perished were Archbishop of Port-au-Prince Joseph Serge Miot and opposition leader Micha Gaillard. The headquarters of the United Nations Stabilization Mission in Haiti (MINUSTAH), situated in the capital also collapsed killing the Mission's Chief, Hédi Annabi.  

Numerous countries took action to appeals for humanitarian aid, transferring funds and sending rescue and medical teams, engineers and support personnel. Communication systems, air, sea, and land transport services, hospitals, and electrical networks had been damaged by the quake, which hindered rescue and aid work; uncertainty over who was in charge, air traffic overcrowding, and issues with prioritization of flights additionally complicated early relief efforts.  Port-au-Prince's morgues were rapidly inundated; tens of thousands of bodies were buried in mass graves.  As rescues slowed down, supplies, medical care and sanitation became the main concern. Holdups in aid circulation led to angry demands from aid workers and survivors, and various pillaging and periodic violence were observed.  

Amid the extensive destruction and damage all over Port-au-Prince and elsewhere, essential infrastructure required to respond to the disaster was severely destroyed or damaged. There was substantial damage to communications infrastructure.  The public telephone system was not accessible, and two of Haiti's leading cellular phone providers, Digicel and Comcel Haiti both complained that their services had been affected by the quake. According to Reporters Sans Frontières (RSF), the majority of the radio stations went off the air and merely 20 of the 50 stations in Port-au-Prince were back on air a week following the quake.  

In the evenings following the quake, countless people slept in the streets, on pavements, in cars, or in temporary shanty towns either because their homes had been ruined, or they feared remaining structures would not endure aftershocks.  Building standards are low in Haiti and the country has no building codes. Engineers have affirmed that it is doubtful many buildings would have stood through any sort of disaster.  Structures are regularly raised anywhere they can fit; a number of buildings were constructed on hills with inadequate foundations or steel works. A spokesperson for Catholic Relief Services has projected that about two million Haitians lived as squatters on territory they did not own.  The nation also suffered from deficiencies of fuel and potable water even prior to the quake.  

On January 22nd, a charity telethon called Haiti Now: A Global Benefit for Earthquake Relief was held and was the most broadly circulated telethon in history.  Plans for the telethon were advertised by MTV Networks three days after the 2010 Haiti quake hit.  Money raised by the telethon and from the sales of its video and album, which were immediately accessible on iTunes, were spread to seven charities doing aid work in Haiti. By January 23rd, the telethon had raised over US$58 million.  

Assisting refugee immigration into Canada was discussed by Canadian Prime Minister Stephen Harper, and in the United States, Haitian refugees were given Temporary Protected Status which allows approximately 100,000 illegal immigrant Haitians in the country to live legally for 18 months. President Barack Obama declared that former presidents Bill Clinton who is also the UN special envoy to Haiti, and George W. Bush would help raise money for Haiti's restoration. Secretary of State Hillary Clinton visited Haiti on January 16th to inspect the damage and confirmed that US$48 million had been raised by now in the United States to help Haiti recuperate.  After the conference with Secretary Clinton, President Préval said that the highest precedence in Haiti's revival were founding a functioning government, clearing roads, and clearing the streets of corpses to ensure sanitary conditions.  

Although the recent natural disaster was a tragic punishment to an already impoverished nation, the subsequent worldwide support in rebuilding Haiti could be viewed as a blessing in disguise. While Haiti was the poorest nation in the Western Hemisphere, with all the new investments and attention, it could very well become one of the hot-spots for international travel and tourism. The worldwide efforts made for these wonderful people will no doubt improve more aspects of everyone’s lives, though indirectly. Fortunately, Haiti was not overtaken by war and intentional killing for anyone’s gain. This makes for a peaceful reconciliation with their future. Haiti will soon be the physical paradise to match its people’s kindness.

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The First Case In Phytopathogenic Bacteria Ralstonia Solancearum Biology Essay

Biology » The First Case In Phytopathogenic Bacteria Ralstonia Solancearum Biology Essay

Filamentous phages belong to the genus Inovirus, members of which infect almost exclusively Gram-negative bacteria. The virions of these phages are slender filaments usually about 6 nm in diameter and 800–2000 nm long, comprising a helical capsid of several thousand copies of the major coat protein (pVIII) surrounding a single-stranded circular DNA genome about of 5–8 kb, encoding around 10 genes (Marvin, 1998). These phages usually use type IV pili as receptors to infect bacterial cells (Marvin, 1998).

Infection of bacteriophage to the host cells causes many change in morphology, physiology and genetics. Webbs et al. (2004) found that Pseudomonas aeruginosa, a human lung pathogen, to be form small colony variant (SCV) caused by Pf4 phage infection. Infection of Pf5 phage was reported to be increase the virulence of P. aeruginosa (). Moreover, virulence factor of pathogenic bacterias have been shown to be encoded by prophage (Brussow et al., 2004). CTX phage was reported to be increase the virulence of host bacteria, Vibrio cholera, by promoting CT toxin that affect to the development cholera disease (Davis and Waldor, 2003). Indeed, the define exotoxin from pathogenic bacteria, Shiga toxin by Escherichia coli (Johannes and Römer, 2010); botulism toxin by; diptheria toxin by , have been show to be expressed from phage-encoded gene.

In Phytopathogenic bacteria, phages have been reporting to infects and affects the virulence of host bacteria. Filamentous phage Xf and Xf2 were reported to infect Xanthomonas campestris pv oryzae NP5850 and caused increasing virulence due to overproduction of extracellular polysaccharides (Kamiunten and Wakitomo, 1982). Moreover, Tseng et al. (1990) reported that filamentous phage Lf which infect X. campestris pv campestri increased virulence by promoting EPS production.

Recently, Yamada et al. (2007) have been succeed to isolate various bacteriophage that infect phytopathogen, Ralstonia solanacearum. Moreover, Kawasaki et al. (2008) characterized the genome of two kind of Ff-like phage (inoviridae),RSS1 and RSM1, were have host genome integration activity. Askora et al. (2009) also found a Ff-like phage, RSM3 and RSM4, that are enhance bacterial cell aggregation and reduce the bacterial host virulence. However, detailed information of cell aggregation and reducing virulence is unclear.

R. solanacearum, a widely distributed soil-borne pathogen belonging to the ß subdivision of Proteobacteria, causes a lethal wilting disease of more than 200 plants species including economically important crops (Hayward, 2000). During infection, bacterial express virulence and pathogenicity factors resulting in typical wilting symptoms. Virulence and pathogenicity of R. solanacearum was known controlled by T2SS and T3SS (Poueymiro and Genin, 2009). As virulence factors, R. solanacearum produce consortium of plant cell wall-degrading enzymes (CWDEs), which are secreted via the type II secretion system (T2SS), such as ß-1,4-endoglucanase (Egl), endopolygalacturonase (PehA), exopolygalacuturonases (PehB and PehC), ß -1,4-cellobiohydrolase (CbhA) and a pectin methyl esterase (Pme) (Denny et al., 1990; González and Allen 2003; Huang and Allen 2000; Tans-Kersten et al., 1998). Moreover, secretion of protein (T3Es) via Type III Secretion System (T3SS) was known as important factor of bacteria pathogenicity. Loss of these secretions causes the loss ability to infect host-plant (Genin et al., 2005). During pathogen infection into plant host, plant will enhance and alter some physiological chance to challenge pathogen infection such as expression of pathogenesis-related gene that encode pathogenesis related protein (PR-protein). Hase et al. (2006) showed that Tomato pathogen infection, Pythium oligandrum, was shown high expression of PR-2b, PR-3b and PR-5b gene of plant which related to the expression of PR-protein. Moreover, Aime et al. (2008) compared infection tomato plant with virulence and avirulent strain of Fusaium oxysporum which showed high accumulation of 5 PR-protein in root and leaves of tomato inoculated with virulent strain compared with avirulent strain.

In this study, we showed an evidance of avirulent formation of R. solanacearum after infection by filamentous phage RSM3.This study was conducted both in bacterial cell and in the interaction of host-pathogen.

To observe the culture color, a single colony of Twenty four house cultures in CPG Agar of Ralstonia solanacearum was picked-up and transfer to CPG broth and was incubated in 28OC with shaking 250-300 rpm until 3 days. Changing of culture color was recorded every day. Culture characteristic on CPG agar was determined by streak plate of OD600 1.0 of 24 hours bacterial culture. To obtain a single colony size, a twenty four hours culture was recovered by centrifugation and was washed two times with ddH2O and was adjusted OD600 of 0.1 and was streaked onto CPG and MM agar. Observation was done after 48 hour of incubation in 28OC.

Twenty four hours cultures in CPG of R. solanacearum was adjusted to OD600 of 0.01 as initial OD with CPG Broth. The culture was incubated in 28OC with shaking 250-300 rpm and was measured the OD600 every 1 hour grown for 1 day at 28OC. Curve of bacterial growth was calculated using absorbance on OD600 and time of incubation. To observe the change of characteristic of liquid culture, bacteria was cultured in liquid CPG for 3 days and observed for color change of liquid CPG medium.

Aggregation assay was performed from Bacterial cell from Twenty four hours cultures in CPG bya harvested cells by centrifugation at 15,000 x rpm for 2 min at 4°C, washed three times with ddH2O and adjusted the OD660 of 1.0 with 1 x PBS pH 7.0. Suspension was incubated without agitation in 28OC. absorbance at 660 nm of upper suspension (100 µL) was measured after 0, 0.5, 1, 2, 4, and 6 h of incubation. Percentage of aggregation curves were then constructed following the formula (Eboigbodin et al, 2005).

% Aggregation= OD0- ODtOD0 x 100

where OD0 is the optical density at 660 nm of bacteria immediately after resuspended with 1 x PBS and ODt is the optical density after particular time.

Cultures of R. solanacearum were grown for 1 day at 28OC in CPG broth. Bacterial cells were obtain by centrifugation at 15.000 rpm, 4OC, for 2 minutes and were washed with ddH2O two times. Pellet was resuspended with ddH2O and was adjusted the OD600 to 1.0. Fifty microliter of suspension was dropped into test media for each assay (MM for twitiching motility, SWM for swimming motility and SRM for swarming motility). Motility was observed by measuring the diameter of dropped-culture up to 6 days.

To test the movement in tomato stem, GFP-expressing strain was used in the experiment. Both strains, MAFF106603 contain pRSS12 and its infected cell by FRSM3 was grown in CPG media for 24 hours. Bacterial cells were obtain by centrifugation at 15.000 rpm, 4OC, for 2 minutes and were washed with ddH2O two times. Pellet was resuspended with ddH2O and was adjusted the OD600 to 1.0. One microliter of suspension was injected into tomato stem between cotyledon and the first leaf and incubated at 28OC. After 1 week incubation, plant stem was cut 20 µm in thickness with microtome and then observed using a Leica MZ16 microscope with GFP3 filter.

Total endoglucanase activity was quantified by measuring the reduction sugar (Nelson, 1944) released during incubation at 50OC for 4 hours with 4 mg/ml of carboxyl metylcellulose in 120 mM phosphate buffer (pH 7.0) In soluble material was removed by low speed centrifugation before absorbency readings were taken on 540 nm. One unit of enzyme activity was defined as releasing 1 nmole/minute of glucose.

Cultures of R. solanacearum were grown for 3 days at 28OC in EG broth (Denny et al., 1990). To recover EPS, culture supernatants were adjusted to 0.1 M NaCl and 4 volume of acetone were added. After incubating overnight at 4OC, precipitated material was recovered by centrifugation (15.000 rpm, 10 minutes, 4OC), dissolved in 200 µl of ddH2O, heated at 65OC for 10 minutes and centrifuged for 5 minutes to remove in soluble material. The concentration of hexosamine in culture supernatants was estimated with a modified Elson and Morgan reaction. Appropriately diluted samples (0.45 ml) were mixed with 0.15 ml of concentrated HCl, hydrolyzed at boiled water (110OC) for 30 minutes in sealed tube and the colorimetric assay performed. The results were read at OD530, the background due to residual media components substraced, and the hexosamine concentration determined from N-acetyl D-glucosamine standard curve. N-acetyl D-glucosamine standards were subjected to the entire analysis procedure beginning with hydrolysis step.

Cells of R. solanacearum strains were streaked heavily on minimal medium plates (Clough et al., 1994) and incubated for about 22-24 hours. The colonies were washed off in a small volume of 10 mM Tris-HCL buffer pH 8, and the cell suspension was forced five times through a 25-gauge hypodermic needle. Bacterial cells were removed by centrifugation with a R12A2 rotor in a Hitachi himac CR21E centrifuge at 8,000× rpm for 20 min at 4°C. The bacterial surface appendages were collected by ultracentrifugation with a R12A2 rotor in a Hitachi himac CR21E centrifuge at 136,000×g for 60min. Precipitated exostructure were subjected to Tris-Tricine PAGE according to Schagger and von Jagow (1987).

All strains, R. solanacearum MAFF106603 and its infected cell by FRSM3, were grown in Minimal Medium (MM) at 28OC for 24 hours. The new sub culture were made by adjusting the OD600 to 0.02-0.03 in new MM and continued growing to reach OD600 of 0.1.

Total RNA was prepared from 3 ml of the exponential phase culture with RNeasy Mini columns (Qiagen), and was eluted in 60 µl of DEPC-treated water. The total RNA was treated with Recombinant DNase I (Takara) to remove any genomic DNA contamination by incubation with 10 U of RNase-free DNase I for 30 min at 37°C. The DNaseI was inactivated by phenol/chloroform extraction method. To confirm the presence of DNA contaminant, a 30 PCR cycles was performed using a gene specific primer (Table 1.) with DNA genome of MAFF106603 as a positive control.

The cDNA of target genes was synthezed by using M-MLV Reverse Transcriptase RNase H- (ReverTra Ace, Toyobo, Osaka). Specific primers were designed using the Primer3 (v.0.4.0) software (http://frodo.wi.mit.edu/primer3/#PRIMER_MAX_TEMPLATE_MISPRIMING) and were checked for gene specificity using DDBJ/Blast (v.2.2.18). Breafly, 20 µl of Reaction Mixture (5 µl of 0.1-1 µg total RNA, 1 µl of 5 pmoles of gene spesific primer, 4 µl of 5X ReverTra Ace Buffer, 2 µl of 10 mM dNTPs, 1 µl of 100 units ReverTra Ace and 7 µl of DEPC-treated water) was incubated for 60 minutes at 42OC and was inactivated by incubation at 99OC for 5 minutes. Negative control reactions to eliminate the possibility that residual DNA was amplified were performed in the same way, except that the RT was omitted from the reaction mixtures.

Real-time PCR was performed using a Line Gene Fluorescence quantitative detection system (BioFlux, Tokyo) with cDNAs prepared from R. solanacearum MAFF106603 strains. A PCR mixture containing SYBR-green (SYBR premix ExTaq, Takara Shuzo, Kyoto) was used. PCR reactions in a final volume of 10 µl reaction mixture containing 5 µl PCR mixture, 1 µl diluted cDNA and 0.5 µM each primer (Table 1.) were carried out under the following conditions: 3 min at 95°C and 45 cycles at 95°C for 10 s, 62°C for 10 s, and 72°C for 15 s. At the end of the program, the specificity of the primer set was confirmed by melting curve analysis (65-95°C with a heating rate of 0.5°C/min). The copy numbers of spesific target gene and 16s rRNA were estimated by comparing the results of real-time PCR with several dilutions (102, 103, 104, 105 copies/µl) of each gene. The mRNA level of 16s rRNA was used to normalize the expression ratio of each gene.

Table 1. Primers used in real-time qRT-PCR study

Target

Forward primer 5'–3'

Reverse primer 5'–3'

Size (bp)

egl

CAG CGC GAC CTA CTA CAA GA

299

hrpB

TTC TCG ATG ATG TAG CGA TAG G

238

phcB

CTA CCA GAT CGT CGT CAA TGA A

172

pehC

AGT CAA ACG ATT GCC TGA ACT A

227

16srRNA

CTA GAG TGT GTC AGA GGG AGG TAG A

349

Note. Bolded characters of oligo primer sequence refers to the Primer used in cDNA synthesis.

Table 2. The tested genes and their putative functions

Gene

Function

egl

Endoglucanase, enzyme which involved in degradation of plant cell wall glucans. (Roberts et al. 1988)

hrpB

Regulator the expression of T3SS biosynthesis genes, and probably >60 effector substrates, and T3SS-dependent export pathway (Occhialini et al., 2005).

phcB

Requiring for production of an extracellular factor (EF), identified as the fatty acid derivative 3-hydroxypalmitic acid methyl ester (3-OH PAME), which function as autoinducer (quorum sensing signal) in R. solanacearum (Flavier et al., 1997a, Flavier et al., 1997b)

pehC

Exopolygalacturonase (Gonzalez and Allen., 2003).

16srRNA

Encode 16S ribosomal RNA.

Virulence assay and HR test

Tomato plants were cultivated in 5-cm pots filled with a soil–peat mixture. Plants (4 leaves) were selected for inoculation. Twenty four hours bacterial culture was centrifuged at 15.000 rpm, 4OC, for 2 minutes and were washed with ddH2O two times. Pellet was resuspended with d ddH2O and was adjusted the OD600 to 1.0. One microliter of suspension was injected into 6 weeks old tomato stem between cotyledon and the first leaf and incubated at 28OC. As a control, distilled water was injected in the same manner. Disease index was observed following Poueymiro et al. (2009) up to 1 week after inoculation with scale ranging from 0 to 4, according to the percentage of wilted plants (0= no wilt; 1 = 1 to 25%; 2= 26-50%; 3=51-75%; 4=>75%).

HR-eliciting ability was tested by infiltrating a serial dilution of R. solanacearum strain solution into the intercellular space of tobacco leaves (Nicotiana tabacum) (Kim et al., 1997). Plants were incubated in 25OC and hypersensitive response was observed 24-48 hours after infiltration.

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